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Sharrack N, Biglands JD, Broadbent DA, Kellman P, Chow K, Greenwood JP, Levelt E, Plein S, Buckley DL. The impact of water exchange on estimates of myocardial extracellular volume calculated using contrast enhanced T 1 measurements: A preliminary analysis in patients with severe aortic stenosis. Magn Reson Med 2024; 91:1637-1644. [PMID: 38041477 PMCID: PMC10872615 DOI: 10.1002/mrm.29956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/06/2023] [Accepted: 11/14/2023] [Indexed: 12/03/2023]
Abstract
PURPOSE Guidelines recommend measuring myocardial extracellular volume (ECV) using T1 -mapping before and 10-30 min after contrast agent administration. Data are then analyzed using a linear model (LM), which assumes fast water exchange (WX) between the ECV and cardiomyocytes. We investigated whether limited WX influences ECV measurements in patients with severe aortic stenosis (AS). METHODS Twenty-five patients with severe AS and 5 healthy controls were recruited. T1 measurements were made on a 3 T Siemens system using a multiparametric saturation-recovery single-shot acquisition (a) before contrast; (b) 4 min post 0.05 mmol/kg gadobutrol; and (c) 4 min, (d) 10 min, and (e) 30 min after an additional gadobutrol dose (0.1 mmol/kg). Three LM-based ECV estimates, made using paired T1 measurements (a and b), (a and d), and (a and e), were compared to ECV estimates made using all 5 T1 measurements and a two-site exchange model (2SXM) accounting for WX. RESULTS Median (range) ECV estimated using the 2SXM model was 25% (21%-39%) for patients and 26% (22%-29%) for controls. ECV estimated in patients using the LM at 10 min following a cumulative contrast dose of 0.15 mmol/kg was 21% (17%-32%) and increased significantly to 22% (19%-35%) at 30 min (p = 0.0001). ECV estimated using the LM was highest following low dose gadobutrol, 25% (19%-38%). CONCLUSION Current guidelines on contrast agent dose for ECV measurements may lead to underestimated ECV in patients with severe AS because of limited WX. Use of a lower contrast agent dose may mitigate this effect.
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Affiliation(s)
- Noor Sharrack
- Biomedical Imaging, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - John D Biglands
- Biomedical Imaging, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
- Department of Medical Physics & Engineering, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - David A Broadbent
- Biomedical Imaging, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
- Department of Medical Physics & Engineering, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Peter Kellman
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Kelvin Chow
- Cardiovascular MR R&D, Siemens Medical Solutions USA, Inc., Chicago, Illinois, USA
| | - John P Greenwood
- Biomedical Imaging, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - Eylem Levelt
- Biomedical Imaging, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - Sven Plein
- Biomedical Imaging, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - David L Buckley
- Biomedical Imaging, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
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Shin HG, Li X, Heo HY, Knutsson L, Szczepankiewicz F, Nilsson M, van Zijl PCM. Compartmental anisotropy of filtered exchange imaging (FEXI) in human white matter: What is happening in FEXI? Magn Reson Med 2024. [PMID: 38525601 DOI: 10.1002/mrm.30086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 01/30/2024] [Accepted: 02/28/2024] [Indexed: 03/26/2024]
Abstract
PURPOSE To investigate the effects of compartmental anisotropy on filtered exchange imaging (FEXI) in white matter (WM). THEORY AND METHODS FEXI signals were measured using multiple combinations of diffusion filter and detection directions in five healthy volunteers. Additional filters, including a trace-weighted diffusion filter with trapezoidal gradients, a spherical b-tensor encoded diffusion filter, and a T2 filter, were tested with trace-weighted diffusion detection. RESULTS A large range of apparent exchange rates (AXR) and both positive and negative filter efficiencies (σ) were found depending on the mutual orientation of the filter and detection gradients relative to WM fiber orientation. The data demonstrated that the fast-diffusion compartment suppressed by diffusional filtering is not exclusively extra-cellular, but also intra-cellular. While not comprehensive, a simple two-compartment diffusion tensor model with water exchange was able to account qualitatively for the trends in positive and negative filtering efficiencies, while standard model imaging (SMI) without exchange could not. This two-compartment diffusion tensor model also demonstrated smaller AXR variances across subjects. When employing trace-weighted diffusion detection, AXR values were on the order of the R1 (=1/T1) of water at 3T for crossing fibers, while being less than R1 for parallel fibers. CONCLUSION Orientation-dependent AXR and σ values were observed when using multi-orientation filter and detection gradients in FEXI, indicating that WM FEXI models need to account for compartmental anisotropy. When using trace-weighted detection, AXR values were on the order of or less than R1, complicating the interpretation of FEXI results in WM in terms of biological exchange properties. These findings may contribute toward better understanding of FEXI results in WM.
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Affiliation(s)
- Hyeong-Geol Shin
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Xu Li
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hye-Young Heo
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Linda Knutsson
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Medical Radiation Physics, Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Filip Szczepankiewicz
- Department of Medical Radiation Physics, Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Markus Nilsson
- Department of Radiology, Clinical Sciences Lund, Lund University, Lund, Sweden
- Department of Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden
| | - Peter C M van Zijl
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Jensen JH. Diffusional kurtosis time dependence and the water exchange rate for the multi-compartment Kärger model. Magn Reson Med 2024; 91:1122-1135. [PMID: 37957820 PMCID: PMC11027117 DOI: 10.1002/mrm.29926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/02/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023]
Abstract
PURPOSE To demonstrate an analytic formula giving the time dependence of the diffusional kurtosis for the Kärger model (KM) with an arbitrary number of exchanging compartments and its application in estimating the mean KM water exchange rate. THEORY AND METHODS The general formula for the kurtosis is derived from a power series solution for the multi-compartment KM. A lower bound on the exchange rate is established from the observation that the kurtosis is always a logarithmically convex function of time. Both the kurtosis time dependence and the lower bound are illustrated with numerical calculations. The lower bound is also applied to previously published data for the time dependence of the kurtosis in both brain and tumors. RESULTS The kurtosis for the multi-compartment KM is given by a sum in which each term is associated with an eigenvector of the exchange rate matrix. The lower bound is determined from the most negative value for the logarithmic derivative of the kurtosis with respect to time. In the cerebral cortex, the lower bound is found to vary from 15 to 76 s-1 , depending on the experimental details, while for the tumors considered, it varies from 2 to 4 s-1 . CONCLUSION The time dependence of the kurtosis for the multi-compartment KM has a simple analytic solution that allows a lower bound for the mean KM water exchange rate to be determined directly from experiment. This may be useful in tissues with complex microstructure that is difficult to model explicitly.
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Affiliation(s)
- Jens H. Jensen
- Center for Biomedical Imaging, Medical University of South Carolina, Charleston, South Carolina
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina
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Pérez-Anta I, Rubio E, López-Serrano FR, Garcés D, Andrés-Abellán M, Picazo M, Chebbi W, Arquero R, García-Morote FA. Transpiration Dynamics of Esparto Grass ( Macrochloa tenacissima (L.) Kunth) in a Semi-Arid Mediterranean Climate: Unraveling the Impacts of Pine Competition. Plants (Basel) 2024; 13:661. [PMID: 38475507 DOI: 10.3390/plants13050661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/23/2024] [Accepted: 02/24/2024] [Indexed: 03/14/2024]
Abstract
Macrochloa tenacissima (M. tenacissima), or esparto, is a perennial tussock grass that coexists with Pinus halepensis (P. halepensis) in semi-arid Mediterranean woodlands. This research was carried out to explore diurnal transpiration at leaf level in esparto grass under different levels of pine-esparto competition and in contrasting environmental soil water conditions. The measurement period spanned from the summer of 2020 to the spring of 2021. The relationship between transpiration and competition was conducted in open and closed P. halepensis stands, and the type of leaf (green, senescent) and the maturity of the esparto grass were taken into account. We observed a higher control of transpiration in green leaves, and the correlations between the transpiration and pine competition were noted exclusively in this type of leaf. Our results demonstrated a significant impact of pine competitors (closed stands) on the transpiration of esparto grass, particularly during seasons characterized by scenarios of high water demand: the summer drought period and the commencement of the growing and flowering period (spring). Furthermore, our findings revealed a greater response to transpiration in mature bushes compared to young ones under severe water stress, indicating a higher adaptation to drought by esparto as it ages. Although our results confirmed that PAR increased transpiration in all seasons and in both stands, which is attributable to the heliophilia of esparto grass, the site effects on transpiration could also be attributable to competition for water, especially during periods of drought. These results may have important implications for the dynamics and management of these semi-arid mixed woodlands, as well as the planning of reforestation programs aimed at restoring esparto grass formations.
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Affiliation(s)
- Iván Pérez-Anta
- Environment and Forest Resources Group, Renewable Energy Research Institute, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - Eva Rubio
- Applied Physics Department, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - Francisco Ramón López-Serrano
- Environment and Forest Resources Group, Renewable Energy Research Institute, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
- Higher Technical School of Agricultural and Forest Engineering, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - Diego Garcés
- Environment and Forest Resources Group, Renewable Energy Research Institute, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - Manuela Andrés-Abellán
- Environment and Forest Resources Group, Renewable Energy Research Institute, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
- Higher Technical School of Agricultural and Forest Engineering, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - Marta Picazo
- Environment and Forest Resources Group, Renewable Energy Research Institute, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - Wafa Chebbi
- Environment and Forest Resources Group, Renewable Energy Research Institute, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - Rocío Arquero
- Environment and Forest Resources Group, Renewable Energy Research Institute, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - Francisco Antonio García-Morote
- Environment and Forest Resources Group, Renewable Energy Research Institute, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
- Higher Technical School of Agricultural and Forest Engineering, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
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Chen Z, Lai JHC, Xu J, Zhang H, Huang J, Chan KWY. The effect of aquaporin-4 inhibition on cerebrospinal fluid-tissue water exchange in mouse brain detected by magnetization transfer indirect spin labeling MRI. NMR Biomed 2024:e5093. [PMID: 38163739 DOI: 10.1002/nbm.5093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 11/19/2023] [Accepted: 11/27/2023] [Indexed: 01/03/2024]
Abstract
The fluid transport of cerebrospinal fluid (CSF) and interstitial fluid in surrounding tissues plays an important role in the drainage pathway that facilitates waste clearance from the brain. This pathway is known as the glymphatic or perivascular system, and its functions are dependent on aquaporin-4 (AQP4). Recently, magnetization transfer indirect spin labeling (MISL) magnetic resonance imaging (MRI) has been proposed as a noninvasive and noncontrast-enhanced method for detecting water exchange between CSF and brain tissue. In this study, we first optimized the MISL sequence at preclinical 3 T MRI, and then studied the correlation of MISL in CSF with magnetization transfer (MT) in brain tissue, as well as the altered water exchange under AQP4 inhibition, using C57BL/6 mice. Results showed a strong correlation of MISL signal with MT signal. With the AQP4 inhibitor, we observed a significant decrease in MISL value (P < 0.05), suggesting that the hampered AQP4 activity led to decreased water exchange between CSF and brain tissue or the impairment of the glymphatic function. Overall, our findings demonstrate the potential application of MISL in assessing brain water exchange at 3 T MRI and its potential clinical translation.
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Affiliation(s)
- Zilin Chen
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Joseph H C Lai
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Jiadi Xu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hao Zhang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Jianpan Huang
- Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong, China
| | - Kannie W Y Chan
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China
- Tung Biomedical Sciences Centre (TBSC), Hong Kong, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
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Liu P, Wu J, He C, Wang W. ENDOANGEL versus water exchange for the detection of colorectal adenomas. Therap Adv Gastroenterol 2023; 16:17562848231218570. [PMID: 38116388 PMCID: PMC10729641 DOI: 10.1177/17562848231218570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 11/10/2023] [Indexed: 12/21/2023] Open
Abstract
Background Recently, the ENDOANGEL (EN) system, a computer-assisted detection technique, and water exchange (WE) assisted colonoscopy have both been shown to increase the colorectal adenoma detection rate (ADR). Objectives The aim of this study was to compare the ADR between EN- and WE-assisted colonoscopy. Design This was a retrospective study. Methods Data from patients who underwent either EN- or WE-assisted colonoscopy between October 2021 and August 2022 were analysed consecutively. The primary outcome measure was the ADR. Results The ADR was found to be similar between the EN and WE groups, with 80 out of 199 (40.2%) patients in the EN group compared to 78 out of 174 (44.8%) patients in the WE group [1.21; 95% confidence interval (CI), 0.80-1.83]. In the analysis using stabilized inverse probability treatment weighting after adjustment for confounding factors, both colonoscopy methods had similar performance in terms of ADR (1.41; 95% CI, 0.88-2.27). Conclusion EN was found to be comparable to WE in terms of ADR during colonoscopy, and both methods may be effectively used in clinical practice.
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Affiliation(s)
- Pengwei Liu
- Department of Gastroenterology, Yijishan Hospital of Wannan Medical College, Wuhu, China
| | - Jie Wu
- Department of Gastroenterology, Yijishan Hospital of Wannan Medical College, Wuhu, China
| | - Chiyi He
- Department of Gastroenterology, Yijishan Hospital of Wannan Medical College, No. 2 Zheshan West Road, Wuhu 241001, China
| | - Wei Wang
- Department of Gastroenterology, Yijishan Hospital of Wannan Medical College, No. 2 Zheshan West Road, Wuhu 241001, China
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Wang Z, Wang B, Li Z, Han G, Meng C, Jiao B, Guo K, Hsu YC, Sun Y, Liu Y, Bai R. The Consistence of Dynamic Contrast-Enhanced MRI and Filter-Exchange Imaging in Measuring Water Exchange Across the Blood-Brain Barrier in High-Grade Glioma. J Magn Reson Imaging 2023; 58:1850-1860. [PMID: 37021659 DOI: 10.1002/jmri.28729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 03/28/2023] [Accepted: 03/28/2023] [Indexed: 04/07/2023] Open
Abstract
BACKGROUND Water exchange across blood-brain barrier (BBB) (WEXBBB ) is an emerging biomarker of BBB dysfunction with potential applications in many brain diseases. Several MRI methods have been proposed to measure WEXBBB , but evidence remains scarce whether different methods can produce comparable WEXBBB . PURPOSE To explore whether dynamic contrast-enhanced (DCE)-MRI and vascular water exchange imaging (VEXI) could produce comparable WEXBBB in high-grade glioma (HGG) patients. STUDY TYPE Prospective cross-sectional. SUBJECTS 13 HGG patients (58.4 ± 9.4 years, 9 females, 4 WHO III and 9 WHO IV). FIELD STRENGTH/SEQUENCE A 3 T, spoiled gradient-recalled-echo DCE-MRI and VEXI containing two pulsed-gradient spin-echo blocks separated by a mixing block. ASSESSMENTS The enhanced tumor and contralateral normal-appearing white matter (cNAWM) volume-of-interests (VOIs) were drew by two neuroradiologists. And whole-brain NAWM and normal-appearing gray matter (NAGM) without tumor-affected regions were segmented by automated segmentation algorithm in FSL. STATISTICAL TESTS Student's t-test was used to evaluate parameters difference between cNAWM and tumor, NAGM and NAWM, respectively. The correlation between vascular water efflux rate constant (kbo ) from DCE-MRI and apparent exchange rate across BBB (AXRBBB ) from VEXI was evaluated by Pearson correlation. P < 0.05 was considered statistically significant. RESULTS Compared with cNAWM, both kbo and AXRBBB were significantly reduced in tumor (kbo = 3.50 ± 1.18 sec-1 vs. 1.03 ± 0.75 sec-1 ; AXRBBB = 3.54 ± 1.11 sec-1 vs. 1.94 ± 1.04 sec-1 ). Both kbo and AXRBBB showed significantly higher values in NAWM than NAGM (kbo = 3.50 ± 0.59 sec-1 vs. 2.10 ± 0.56 sec-1 ; AXRBBB = 3.35 ± 0.77 sec-1 vs. 2.07 ± 0.52 sec-1 ). The VOI-averaged kbo and AXRBBB were also linearly correlated in tumor, NAWM, and NAGM (r = 0.59). DATA CONCLUSION DCE-MRI and VEXI showed comparable and correlated WEXBBB in HGG patients, suggesting that the consistence and reliability of these two MRI methods in measuring WEXBBB . EVIDENCE LEVEL 2. TECHNICAL EFFICACY Stage 1.
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Affiliation(s)
- Zejun Wang
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Run Shaw Hospital and Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Bao Wang
- Department of Radiology, Qilu Hospital of Shandong University, Jinan, China
| | - Zhaoqing Li
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Run Shaw Hospital and Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Guangxu Han
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Run Shaw Hospital and Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Cheng Meng
- Department of Neurosurgery, Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Bingjie Jiao
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Run Shaw Hospital and Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Kaiyue Guo
- Department of Neurosurgery, Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Yi-Cheng Hsu
- MR Collaboration, Siemens Healthcare, Shanghai, China
| | - Yi Sun
- MR Collaboration, Siemens Healthcare, Shanghai, China
| | - Yingchao Liu
- Department of Neurosurgery, Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Ruiliang Bai
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Run Shaw Hospital and Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
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Powell E, Dickie BR, Ohene Y, Maskery M, Parker GJM, Parkes LM. Blood-brain barrier water exchange measurements using contrast-enhanced ASL. NMR Biomed 2023; 36:e5009. [PMID: 37666494 PMCID: PMC10909569 DOI: 10.1002/nbm.5009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 05/17/2023] [Accepted: 06/30/2023] [Indexed: 09/06/2023]
Abstract
A technique for quantifying regional blood-brain barrier (BBB) water exchange rates using contrast-enhanced arterial spin labelling (CE-ASL) is presented and evaluated in simulations and in vivo. The two-compartment ASL model describes the water exchange rate from blood to tissue,k b , but to estimatek b in practice it is necessary to separate the intra- and extravascular signals. This is challenging in standard ASL data owing to the small difference inT 1 values. Here, a gadolinium-based contrast agent is used to increase thisT 1 difference and enable the signal components to be disentangled. The optimal post-contrast bloodT 1 (T 1 , b post ) at 3 T was determined in a sensitivity analysis, and the accuracy and precision of the method quantified using Monte Carlo simulations. Proof-of-concept data were acquired in six healthy volunteers (five female, age range 24-46 years). The sensitivity analysis identified the optimalT 1 , b post at 3 T as 0.8 s. Simulations showed thatk b could be estimated in individual cortical regions with a relative error ϵ < 1 % and coefficient of variation CoV = 30 %; however, a high dependence on bloodT 1 was also observed. In volunteer data, mean parameter values in grey matter were: arterial transit timet A = 1 . 15 ± 0 . 49 s, cerebral blood flow f = 58 . 0 ± 14 . 3 mL blood/min/100 mL tissue and water exchange ratek b = 2 . 32 ± 2 . 49 s-1 . CE-ASL can provide regional BBB water exchange rate estimates; however, the clinical utility of the technique is dependent on the achievable accuracy of measuredT 1 values.
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Affiliation(s)
- Elizabeth Powell
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical EngineeringUniversity College LondonLondonUK
| | - Ben R. Dickie
- Division of Informatics, Imaging and Data Sciences, School of Health Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
- Geoffrey Jefferson Brain Research CentreUniversity of Manchester, Manchester Academic Health Science CentreManchesterUK
| | - Yolanda Ohene
- Geoffrey Jefferson Brain Research CentreUniversity of Manchester, Manchester Academic Health Science CentreManchesterUK
- Division of Psychology, Communication and Human Neuroscience, School of Health Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
| | - Mark Maskery
- Department of NeurologyLancashire Teaching Hospitals NHS Foundation TrustPrestonUK
| | - Geoff J. M. Parker
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical EngineeringUniversity College LondonLondonUK
- Queen Square MS Centre, Institute of NeurologyUniversity College LondonLondonUK
- Bioxydyn LimitedManchesterUnited Kingdom
| | - Laura M. Parkes
- Geoffrey Jefferson Brain Research CentreUniversity of Manchester, Manchester Academic Health Science CentreManchesterUK
- Division of Psychology, Communication and Human Neuroscience, School of Health Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
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9
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Carniato F, Ricci M, Tei L, Garello F, Furlan C, Terreno E, Ravera E, Parigi G, Luchinat C, Botta M. Novel Nanogels Loaded with Mn(II) Chelates as Effective and Biologically Stable MRI Probes. Small 2023; 19:e2302868. [PMID: 37345577 DOI: 10.1002/smll.202302868] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/01/2023] [Indexed: 06/23/2023]
Abstract
Here it is described nanogels (NG) based on a chitosan matrix, which are covalently stabilized by a bisamide derivative of Mn-t-CDTA (t-CDTA = trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid). the Mn(II) complex acts both as a contrast medium and as a cross-linking agent. These nanogels are proposed as an alternative to the less stable paramagnetic nanogels obtained by electrostatic interactions between the polymeric matrix and paramagnetic Gd(III) chelates. The present novel nanogels show: i) relaxivity values seven times higher than that of typical monohydrated Mn(II) chelates at the clinical fields, thanks to the combination of a restricted mobility of the complex with a fast exchange of the metal-bound water molecule; ii) high stability of the formulation over time at pH 5 and under physiological conditions, thus excluding metal leaking or particles aggregation; iii) good extravasation and accumulation, with a maximum contrast achieved at 24 h post-injection in mice bearing subcutaneous breast cancer tumor; iv) high T1 contrast (1 T) in the tumor 24 h post-injection. These improved properties pave the way for the use of these paramagnetic nanogels as promising magnetic resonance imaging (MRI) probes for in vitro and in vivo preclinical applications.
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Affiliation(s)
- Fabio Carniato
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel 11, Alessandria, 15121, Italy
| | - Marco Ricci
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel 11, Alessandria, 15121, Italy
| | - Lorenzo Tei
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel 11, Alessandria, 15121, Italy
| | - Francesca Garello
- Molecular Imaging Centre, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, 10126, Italy
| | - Chiara Furlan
- Molecular Imaging Centre, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, 10126, Italy
| | - Enzo Terreno
- Molecular Imaging Centre, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, 10126, Italy
| | - Enrico Ravera
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino, 50019, Italy
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino, 50019, Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino, 50019, Italy
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino, 50019, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino, 50019, Italy
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino, 50019, Italy
- Giotto Biotech S.r.l., Sesto Fiorentino, 50019, Italy
| | - Mauro Botta
- Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel 11, Alessandria, 15121, Italy
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10
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Arnaert S, Vandebroek V, Persyn D, Cool M, Lambrecht G, Desmet G, Deboever G. A survey among Flemish gastroenterologists about endoscopic sedation practices in colorectal cancer screening. Acta Gastroenterol Belg 2023; 86:527-532. [PMID: 38240547 DOI: 10.51821/86.4.12145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Background & study aims The sedation levels and methods used for colonoscopy in colorectal cancer screening programs vary from country to country and from continent to continent. Little is known in the literature about how frequently the different sedation levels are used in colorectal cancer screening colonoscopies. We made a survey among all Flemish gastroenterologists (GI) to determine how frequently they use the different sedation modalities in this target population and to determine the motives of the GI to opt for one or another sedation modality. Patient and methods An online survey was sent to all 329 Flemish GI by e-mail. A reminder e-mail was sent one month later. Participants could indicate how frequently (by percentage) they used the different sedation methods (no sedation, minimal sedation, conscious sedation, deep sedation) and which sedative medication they administered. In addition, they were asked to indicate their main motives for choosing a specific sedation method. Descriptive statistics were used. Results 112 out of 329 GI answered the questionnaire (response rate 34%). Anesthesia monitored care is the most frequently used sedation modality, followed by conscious sedation. Patient preference is the main motive for most GI to use each sedation modality. Conclusions Anesthesia monitored care is currently the most frequently used sedation regimen to perform a colonoscopy in the FIT positive population or in the colorectal cancer screening program in Flanders. The motives given by the GI for choosing one or another sedation modality are not always congruent with current scientific evidence or guidelines.
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Affiliation(s)
- S Arnaert
- Department of gastroenterology, AZ Damiaan, Oostende, Belgium
| | - V Vandebroek
- Department of gastroenterology, AZ Damiaan, Oostende, Belgium
| | - D Persyn
- Department of gastroenterology, AZ Damiaan, Oostende, Belgium
| | - M Cool
- Department of gastroenterology, AZ Damiaan, Oostende, Belgium
| | - G Lambrecht
- Department of gastroenterology, AZ Damiaan, Oostende, Belgium
| | - G Desmet
- Department of pneumology, AZ Damiaan, Oostende, Belgium
| | - G Deboever
- Department of gastroenterology, AZ Damiaan, Oostende, Belgium
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11
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Powell E, Ohene Y, Battiston M, Dickie BR, Parkes LM, Parker GJM. Blood-brain barrier water exchange measurements using FEXI: Impact of modeling paradigm and relaxation time effects. Magn Reson Med 2023; 90:34-50. [PMID: 36892973 PMCID: PMC10962589 DOI: 10.1002/mrm.29616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/25/2023] [Accepted: 01/25/2023] [Indexed: 03/10/2023]
Abstract
PURPOSE To evaluate potential modeling paradigms and the impact of relaxation time effects on human blood-brain barrier (BBB) water exchange measurements using FEXI (BBB-FEXI), and to quantify the accuracy, precision, and repeatability of BBB-FEXI exchange rate estimates at 3 T $$ \mathrm{T} $$ . METHODS Three modeling paradigms were evaluated: (i) the apparent exchange rate (AXR) model; (ii) a two-compartment model (2 CM $$ 2\mathrm{CM} $$ ) explicitly representing intra- and extravascular signal components, and (iii) a two-compartment model additionally accounting for finite compartmentalT 1 $$ {\mathrm{T}}_1 $$ andT 2 $$ {\mathrm{T}}_2 $$ relaxation times (2 CM r $$ 2{\mathrm{CM}}_r $$ ). Each model had three free parameters. Simulations quantified biases introduced by the assumption of infinite relaxation times in the AXR and2 CM $$ 2\mathrm{CM} $$ models, as well as the accuracy and precision of all three models. The scan-rescan repeatability of all paradigms was quantified for the first time in vivo in 10 healthy volunteers (age range 23-52 years; five female). RESULTS The assumption of infinite relaxation times yielded exchange rate errors in simulations up to 42%/14% in the AXR/2 CM $$ 2\mathrm{CM} $$ models, respectively. Accuracy was highest in the compartmental models; precision was best in the AXR model. Scan-rescan repeatability in vivo was good for all models, with negligible bias and repeatability coefficients in grey matter ofRC AXR = 0 . 43 $$ {\mathrm{RC}}_{\mathrm{AXR}}=0.43 $$ s - 1 $$ {\mathrm{s}}^{-1} $$ ,RC 2 CM = 0 . 51 $$ {\mathrm{RC}}_{2\mathrm{CM}}=0.51 $$ s - 1 $$ {\mathrm{s}}^{-1} $$ , andRC 2 CM r = 0 . 61 $$ {\mathrm{RC}}_{2{\mathrm{CM}}_r}=0.61 $$ s - 1 $$ {\mathrm{s}}^{-1} $$ . CONCLUSION Compartmental modelling of BBB-FEXI signals can provide accurate and repeatable measurements of BBB water exchange; however, relaxation time and partial volume effects may cause model-dependent biases.
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Affiliation(s)
- Elizabeth Powell
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical EngineeringUniversity College LondonLondonUK
| | - Yolanda Ohene
- Division of Psychology, Communication and Human Neuroscience, School of Health Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
- Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science CentreUniversity of ManchesterManchesterUK
| | - Marco Battiston
- Queen Square MS CentreUCL Institute of Neurology, University College LondonLondonUK
| | - Ben R. Dickie
- Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science CentreUniversity of ManchesterManchesterUK
- Division of Informatics, Imaging and Data SciencesSchool of Health Sciences, Faculty of Biology, Medicine and Health, University of ManchesterManchesterUK
| | - Laura M. Parkes
- Division of Psychology, Communication and Human Neuroscience, School of Health Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
- Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science CentreUniversity of ManchesterManchesterUK
| | - Geoff J. M. Parker
- Centre for Medical Image Computing, Department of Medical Physics and Biomedical EngineeringUniversity College LondonLondonUK
- Queen Square MS CentreUCL Institute of Neurology, University College LondonLondonUK
- Bioxydyn LimitedManchesterUK
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12
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Zhang Y, Wang Y, Li Z, Wang Z, Cheng J, Bai X, Hsu YC, Sun Y, Li S, Shi J, Sui B, Bai R. Vascular-water-exchange MRI (VEXI) enables the detection of subtle AXR alterations in Alzheimer's disease without MRI contrast agent, which may relate to BBB integrity. Neuroimage 2023; 270:119951. [PMID: 36805091 DOI: 10.1016/j.neuroimage.2023.119951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 02/21/2023] Open
Abstract
Blood-brain barrier (BBB) impairment is an important pathophysiological process in Alzheimer's disease (AD) and a potential biomarker for early diagnosis of AD. However, most current neuroimaging methods assessing BBB function need the injection of exogenous contrast agents (or tracers), which limits the application of these methods in a large population. In this study, we aim to explore the feasibility of vascular water exchange MRI (VEXI), a diffusion-MRI-based method proposed to assess the BBB permeability to water molecules without using a contrast agent, in the detection of the BBB breakdown in AD. We tested VEXI on a 3T MRI scanner on three groups: AD patients (AD group), mild cognitive impairment (MCI) patients due to AD (MCI group), and the age-matched normal cognition subjects (NC group). Interestingly, we find that the apparent water exchange across the BBB (AXRBBB) measured by VEXI shows higher values in MCI compared with NC, and this higher AXRBBB happens specifically in the hippocampus. This increase in AXRBBB value gets larger and extends to more brain regions (medial orbital frontal cortex and thalamus) from MCI group to the AD group. Furthermore, we find that the AXRBBB values of these three regions is correlated significantly with the impairment of respective cognitive domains independent of age, sex and education. These results suggest VEXI is a promising method to assess the BBB breakdown in AD.
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Affiliation(s)
- Yifan Zhang
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Yue Wang
- National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Zhaoqing Li
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Zejun Wang
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Juange Cheng
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xiaoyan Bai
- Tiantan Neuroimaging Center of Excellence, China National Clinical Research Center for Neurological Diseases, Beijing, China; Department of Radiology, Beijing Tiantan Hospital, Capital Medical University, Beijing Neurosurgical Institute, Beijing, China
| | - Yi-Cheng Hsu
- MR Collaboration, Siemens Healthcare, Shanghai, China
| | - Yi Sun
- MR Collaboration, Siemens Healthcare, Shanghai, China
| | - Shiping Li
- National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Jiong Shi
- National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China.
| | - Binbin Sui
- National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
| | - Ruiliang Bai
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China; Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China; MOE Frontier Science Center for Brain Science and Brain-machine Integration, School of Brain Science and Brain Medicine, Zhejiang University.
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13
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Lin Z, Jiang D, Liu P, Ge Y, Moghekar A, Lu H. Blood-brain barrier permeability in response to caffeine challenge. Magn Reson Med 2022; 88:2259-2266. [PMID: 35754146 PMCID: PMC9420773 DOI: 10.1002/mrm.29355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/17/2022] [Accepted: 05/22/2022] [Indexed: 01/22/2023]
Abstract
PURPOSE Caffeine is known to alter brain perfusion by acting as an adenosine antagonist, but its effect on blood-brain barrier (BBB) permeability is not fully elucidated. This study aimed to dynamically monitor BBB permeability to water after a single dose of caffeine tablet using a non-contrast MRI technique. METHODS Ten young healthy volunteers who were not regular coffee drinkers were studied. The experiment began with a pre-caffeine measurement, followed by four measurements at the post-caffeine stage. Water-extraction-with-phase-contrast-arterial-spin-tagging (WEPCAST) MRI was used to assess the time dependence of BBB permeability to water following the ingestion of 200 mg caffeine. Other cerebral physiological parameters including cerebral blood flow (CBF), venous oxygenation (Yv ), and cerebral metabolic rate of oxygen (CMRO2 ) were also examined. The relationships between cerebral physiological parameters and time were studied with mixed-effect models. RESULTS It was found that, after caffeine ingestion, CBF and Yv showed a time-dependent decrease (p < 0.001), while CMRO2 did not change significantly. The fraction of arterial water crossing the BBB (E) showed a significant increase (p < 0.001). In contrast, the permeability-surface-area product (PS), i.e., BBB permeability to water, remained constant (p = 0.94). Additionally, it was observed that changes in physiological parameters were non-linear with regard to time and occurred at as early as 9 min after caffeine tablet ingestion. CONCLUSION These results suggest an unchanged BBB permeability despite alterations in perfusion during a vasoconstrictive caffeine challenge.
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Affiliation(s)
- Zixuan Lin
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Dengrong Jiang
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peiying Liu
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yulin Ge
- Department of Radiology, New York University, NY, USA
| | - Abhay Moghekar
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hanzhang Lu
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
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Lyons T, Kekedjian C, Glaser P, Ohlin CA, van Eldik R, Rodriguez O, Albanese C, Van Keuren E, Stoll SL. Molecular Parameters Promoting High Relaxivity in Cluster-Nanocarrier Magnetic Resonance Imaging Contrast Agents. ACS Appl Mater Interfaces 2022; 14:10.1021/acsami.2c12584. [PMID: 36283049 PMCID: PMC10502962 DOI: 10.1021/acsami.2c12584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We have investigated the mechanism of relaxivity for two magnetic resonance imaging contrast agents that both employ a cluster-nanocarrier design. The first system termed Mn8Fe4-coPS comprises the cluster Mn8Fe4O12(L)16(H2O)4 or Mn8Fe4 (1) (L = carboxylate) co-polymerized with polystyrene to form ∼75 nm nanobeads. The second system termed Mn3Bpy-PAm used the cluster Mn3(O2CCH3)6(Bpy)2 or Mn3Bpy (2) where Bpy = 2,2'-bipyridine, entrapped in ∼180 nm polyacrylamide nanobeads. Here, we investigate the rate of water exchange of the two clusters, and corresponding cluster-nanocarriers, in order to elucidate the mechanism of relaxivity in the cluster-nanocarrier. Swift-Connick analysis of O-17 NMR was used to determine the water exchange rates of the clusters and cluster-nanocarriers. We found distinct differences in the water exchange rate between Mn8Fe4 and Mn8Fe4-coPS, and we utilized these differences to elucidate the nanobead structure. Using the transverse relaxivity from O-17 NMR line widths, we were able to determine the hydration state of the Mn3Bpy (2) cluster as well as Mn3Bpy-PAm. Using these hydration states in the Swift-Connick analysis of O-17 NMR, we found the water exchange rate to be extremely close in value for the cluster Mn3Bpy and cluster-nanocarrier Mn3Bpy-PAm.
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Affiliation(s)
- Trevor Lyons
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C.20057, United States
| | - Chloe Kekedjian
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C.20057, United States
| | - Priscilla Glaser
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C.20057, United States
| | - C André Ohlin
- Department of Chemistry, Umeå University, Umeå907 36, Sweden
| | - Rudi van Eldik
- Faculty of Chemistry, Nicolaus Copernicus University, Torun87 100, Poland
- Inorganic Chemistry, Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Egerlandstrasse 1, Erlangen91058, Germany
| | - Olga Rodriguez
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, D.C.20057, United States
| | - Christopher Albanese
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, D.C.20057, United States
- Department of Radiology, Georgetown University Medical Center, Washington, D.C.20057, United States
| | - Edward Van Keuren
- Department of Physics, and Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets NW, Washington, D.C.20057, United States
| | - Sarah L Stoll
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C.20057, United States
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15
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Pan C, Guo Z, Luo M. A Simulation Experiment on Quality Dynamics of Reclaimed Water under Different Flow Exchanges. Int J Environ Res Public Health 2022; 19:13091. [PMID: 36293677 PMCID: PMC9603255 DOI: 10.3390/ijerph192013091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
Reclaimed water plays an important role in maintaining urban aquatic ecosystems, especially in areas with water shortages. However, there is little information on water quality dynamics and its driving mechanism in reclaimed water bodies. The simulated experiments were conducted to investigate the effect of flow exchange on water quality dynamics and soil microbial diversity for 100% reclaimed water and mixed water (50% reclaimed and 50% stream water), and the exchange periods ranged from 2 to 40 days. The results showed that the degradation coefficients (K) of CODMn and NH3-N were 0.015 d-1 and 0.001 d-1 for the mixed water, while their K values were negative for the reclaimed water. The flow exchange had little effect on water quality dynamics for the mixed water, which may be attributed to the relatively low concentration of TP in this reclaimed water. A small or great exchange period led to a relatively high fluctuation in K during the experimental period and corresponded to a worse soil microbial diversity. These results indicate that it is not recommended to fill an isolated urban lake with 100% reclaimed water and that a suitable flow exchange period of 5~10 days could help self-purify the water quality.
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16
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Leung FW, Cadoni S, Koo M, Yen AW, Siau K, Hsieh YH, Ishaq S, Cheng CL, Ramirez FC, Bak AW, Karnes W, Bayupurnama P, Leung JW, de Groen PC. A survey of colonoscopists with and without in-depth knowledge of water-aided colonoscopy. J Gastroenterol Hepatol 2022; 37:1785-1791. [PMID: 35613903 DOI: 10.1111/jgh.15896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 05/10/2022] [Accepted: 05/14/2022] [Indexed: 12/09/2022]
Abstract
BACKGROUND AND AIM Endoscopy featured water-aided colonoscopy (WAC) as novel in the Innovation Forum in 2011. Gastrointestinal Endoscopy published a modified Delphi consensus review (MDCR) that supports WAC for clinical practice in 2021. We tested the hypothesis that experience was an important predictor of WAC use, either as water immersion (WI), water exchange (WE), or a combination of WI and WE. METHODS A questionnaire was sent by email to the MDCR authors with an in-depth knowledge of WAC. They responded and also invited colleagues and trainees without in-depth knowledge to respond. Logistic regression analysis was used with the reasons for WAC use treated as the primary outcome. Reports related to WAC post MDCR were identified. RESULTS Of 100 respondents, > 80% indicated willingness to adopt and modify practice to accommodate WAC. Higher adenoma detection rate (ADR) incentivized WE use. Procedure time slots ≤ 30 and > 30 min significantly predicted WI and WE use, respectively. Co-authors of the MDCR were significantly more likely to perform WAC (odds ratio [OR] = 7.5, P = 0.037). Unfamiliarity with (OR = 0.11, P = 0.02) and absence of good experience (OR = 0.019, P = 0.002) were associated with colonoscopists less likely to perform WAC. Reports related to WAC post MDCR revealed overall and right colon WE outcomes continued to improve. Network meta-analyses showed that WE was superior to Cap and Endocuff. On-demand sedation with WE shortened nursing recovery time. CONCLUSIONS An important predictor of WAC use was experience. Superior outcomes continued to be reported with WE.
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Affiliation(s)
- Felix W Leung
- Sepulveda Ambulatory Care Center, VAGLAHS; David Geffen School of Medicine at UCLA, Medicine, North Hills, California, USA
| | - Sergio Cadoni
- Digestive Endoscopy Unit, CTO Hospital, Iglesias, Italy
| | - Malcolm Koo
- Graduate Institution of Long-term Care, Tzu Chi University of Science and Technology, Hualien, Taiwan
| | - Andrew W Yen
- Sacramento Veterans Affairs Medical Center, VANCHCS, Division of Gastroenterology, University of California Davis School of Medicine, Sacramento, California, USA
| | - Keith Siau
- Department of Gastroenterology, Dudley Group Hospitals NHS Foundation Trust, Dudley, UK
| | - Yu-Hsi Hsieh
- School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Sauid Ishaq
- The Dudley Group of Hospitals NHS Trust, Visiting Professor of Medicine and Gastroenterology, Birmingham City University, Birmingham, UK
| | - Chi-Liang Cheng
- Division of Gastroenterology, Department of Internal Medicine, Evergreen General Hospital, Taoyuan, Taiwan
| | - Francisco C Ramirez
- Division of Gastroenterology and Hepatology, Mayo Clinic, Scottsdale, Arizona, USA
| | - Adrian W Bak
- Division of Gastroenterology, Department of Medicine, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - William Karnes
- Digestive Health Institute, University of California Irvine Medical Center, Irvine, California, USA
| | - Putut Bayupurnama
- Division of Gastroenterology and Hepatology, Internal Medicine Department, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Dr. Sardjito General Hospital, Yogyakarta, Indonesia
| | - Joseph W Leung
- Sacramento Veterans Affairs Medical Center, VANCHCS, Division of Gastroenterology, University of California Davis School of Medicine, Sacramento, California, USA
| | - Piet C de Groen
- Division of Gastroenterology, Hepatology and Nutrition, University of Minnesota, Minneapolis, Minnesota, USA
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Hsieh YH, Koo M, Tseng CW. Factors associated with prolonged cecal insertion time in patients undergoing water exchange colonoscopy. J Gastroenterol Hepatol 2022; 37:1326-1332. [PMID: 35451117 DOI: 10.1111/jgh.15869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 03/02/2022] [Accepted: 04/09/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND AND AIM Water exchange is superior to air insufflation in reducing discomfort and increasing adenoma detection during colonoscopy. However, prolonged cecal insertion time is a drawback. This study aims to investigate the factors affecting cecal insertion during water exchange colonoscopy. METHODS We pooled data from five randomized clinical trials that included patients undergoing water exchange colonoscopy. Logistic analysis was performed to determine the independent factors associated with prolonged cecal insertion time (> 15 min). RESULTS The cohort included 912 patients (493 men and 419 women) with a median age of 57 years (interquartile range, 49-64 years). The median cecal insertion time was 13.5 min (interquartile range, 10.9-17.0 min). Multivariate logistic regression analysis indicated that female sex, body mass index < 25 kg/m2 , a history of constipation, no sedation, less experienced endoscopist, Boston Bowel Preparation Scale score ≤ 6, infused water volume during insertion ≥ 1000 mL, and scope length at the cecum ≥ 85 cm were associated with prolonged cecal insertion time. With increasing volume of infused water (1000-2000 mL), the median cecal insertion time increased gradually from 11.4 to 23.0 min (P < 0.001). CONCLUSIONS The current study identified independent factors associated with prolonged cecal insertion time during water exchange colonoscopy. Several factors are modifiable to achieve a shorter insertion time, including better bowel preparation, the use of sedation, more experienced endoscopist, infusing less water during insertion, and maintaining a shorter scope length.
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Affiliation(s)
- Yu-Hsi Hsieh
- Division of Gastroenterology, Department of Internal Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.,School of Medicine, Tzu Chi University, Hualien City, Taiwan
| | - Malcolm Koo
- Graduate Institution of Long-term Care, Tzu Chi University of Science and Technology, Hualien, Taiwan.,Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Chih-Wei Tseng
- Division of Gastroenterology, Department of Internal Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.,School of Medicine, Tzu Chi University, Hualien City, Taiwan
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Wimmler MC, Vovides AG, Peters R, Walther M, Nadezhdina N, Berger U. Root grafts matter for inter-tree water exchange - a quantification of water translocation between root grafted mangrove trees using field data and model based indication. Ann Bot 2022; 130:mcac074. [PMID: 35686514 PMCID: PMC9486923 DOI: 10.1093/aob/mcac074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND AIMS Trees interconnected through functional root grafts can exchange resources, but the effect of exchange on trees remains under debate. A mechanistic understanding of resources exchange via functional root grafts will help understand their ecological implications for tree water exchange for individual trees, groups of trees, and forest stands. METHODS To identify the main patterns qualitatively describing the movement of sap between grafted trees, we reviewed available literature on root grafting in woody plants that focus on tree allometry and resource translocation via root grafts. We then extended the BETTINA model, which simulates mangrove (Avicennia germinans) tree growth on the individual tree scale, in order to synthesize the available empirical information. Using allometric data from a field study in mangrove stands, we simulated potential water exchange and analyzed movement patterns between grafted trees. KEY RESULTS In the simulations, relative water exchange ranged between -9.17 and 20.3 %, and was driven by gradients of water potential, i.e. differences in tree size and water availability. Moreover, the exchange of water through root grafts alters the water balance of trees and their feedback with the soil: grafted trees that receive water from their neighbors reduce their water uptake. CONCLUSIONS Our individual-tree modelling study is a first theoretical attempt to quantify root graft-mediated water exchange between trees. Our findings indicate that functional root grafts represent a vector of hydraulic redistribution, helping to maintain the water balance of grafted trees. This non-invasive approach can serve as a fundament for designing empirical studies to better understand the role of grafted root interaction networks on a broader scale.
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Affiliation(s)
- Marie-Christin Wimmler
- Faculty of Environmental Sciences, Department of Forest Sciences, Chair of Forest Biometrics and Systems Analysis, Technische Universität Dresden, 01062 Dresden, Germany
| | - Alejandra G Vovides
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow, UK
| | - Ronny Peters
- Faculty of Environmental Sciences, Department of Forest Sciences, Chair of Forest Biometrics and Systems Analysis, Technische Universität Dresden, 01062 Dresden, Germany
| | - Marc Walther
- Faculty of Environmental Sciences, Department of Forest Sciences, Chair of Forest Biometrics and Systems Analysis, Technische Universität Dresden, 01062 Dresden, Germany
| | - Nadezhda Nadezhdina
- Institute of Forest Botany, Dendrology and Geobiocenology, Mendel University in Brno, Brno, Czech Republic
| | - Uta Berger
- Faculty of Environmental Sciences, Department of Forest Sciences, Chair of Forest Biometrics and Systems Analysis, Technische Universität Dresden, 01062 Dresden, Germany
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Hsieh YH, Koo M, Tseng CW. Comparison of Procedural Sequences in Sedated Same-Day Bidirectional Endoscopy with Water-Exchange Colonoscopy: A Randomized Controlled Trial. J Clin Med 2022; 11. [PMID: 35268456 DOI: 10.3390/jcm11051365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/21/2022] [Accepted: 02/28/2022] [Indexed: 11/25/2022] Open
Abstract
Background: Previous studies have favored esophagogastroduodenoscopy (EGD) followed by colonoscopy as the optimal sequence in bidirectional endoscopy (BDE) with air insufflation. However, the optimal sequence in same-day BDE with WE colonoscopy is unclear. Methods: A total of 200 patients undergoing BDE with propofol sedation from May 2018 to January 2021 were randomized to either the EGD-first group (n = 100) or the colonoscopy-first group (n = 100). Results: The EGD-first group required a longer cecal-intubation time (median 16.0 min vs. 13.7 min, p < 0.001) and a lower Boston Bowel Preparation Scale score (8.5 vs. 9, p = 0.030) compared with the colonoscopy-first group. However, the EGD-first group needed a significantly lower dose of propofol (200 mg vs. 250 mg, p < 0.001) and a shorter recovery time (7 min vs. 13.5 min, p < 0.001), resulting in a shorter turnover time of the endoscopy room (39.5 min vs. 42.6 min, p = 0.004). There were no differences in the sedation-related adverse events, patients’ satisfaction scores, adenoma-detection rates, or the outcomes of EGD between the two groups. Conclusions: During propofol-sedated BDE, EGD followed by WE colonoscopy was more efficient with a shorter turnover time despite a longer cecal-intubation time (NCT03638713).
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Csupász T, Szücs D, Kálmán FK, Hollóczki O, Fekete A, Szikra D, Tóth É, Tóth I, Tircsó G. A New Oxygen Containing Pyclen-Type Ligand as a Manganese(II) Binder for MRI and 52Mn PET Applications: Equilibrium, Kinetic, Relaxometric, Structural and Radiochemical Studies. Molecules 2022; 27:molecules27020371. [PMID: 35056686 PMCID: PMC8778187 DOI: 10.3390/molecules27020371] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 11/16/2022]
Abstract
A new pyclen-3,9-diacetate derivative ligand (H23,9-OPC2A) was synthesized possessing an etheric O-atom opposite to the pyridine ring, to improve the dissociation kinetics of its Mn(II) complex (pyclen = 3,6,9,15-tetraazabicyclo(9.3.1)pentadeca-1(15),11,13-triene). The new ligand is less basic than the N-containing analogue (H23,9-PC2A) due to the non-protonable O-atom. In spite of its lower basicity, the conditional stability of the [Mn(3,9-OPC2A)] (pMn = −log(Mn(II)), cL = cMn(II) = 0.01 mM. pH = 7.4) remains unaffected (pMn = 8.69), compared to the [Mn(3,9-PC2A)] (pMn = 8.64). The [Mn(3,9-OPC2A)] possesses one water molecule, having a lower exchange rate with bulk solvents (kex298 = 5.3 ± 0.4 × 107 s−1) than [Mn(3,9-PC2A)] (kex298 = 1.26 × 108 s−1). These mild differences are rationalized by density-functional theory (DFT) calculations. The acid assisted dissociation of [Mn(3,9-OPC2A)] is considerably slower (k1 = 2.81 ± 0.07 M−1 s−1) than that of the complexes of diacetates or bisamides of various 12-membered macrocycles and the parent H23,9-PC2A. The [Mn(3,9-OPC2A)] is inert in rat/human serum as confirmed by 52Mn labeling (nM range), as well as by relaxometry (mM range). However, a 600-fold excess of EDTA (pH = 7.4) or a mixture of essential metal ions, propagated some transchelation/transmetalation in 7 days. The H23,9-OPC2A is labeled efficiently with 52Mn at elevated temperatures, yet at 37 °C the parent H23,9-PC2A performs slightly better. Ultimately, the H23,9-OPC2A shows advantageous features for further ligand designs for bifunctional chelators.
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Affiliation(s)
- Tibor Csupász
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (T.C.); (D.S.); (F.K.K.); (O.H.); (I.T.)
- Doctoral School of Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary
| | - Dániel Szücs
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (T.C.); (D.S.); (F.K.K.); (O.H.); (I.T.)
- Doctoral School of Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary
- Department of Medical Imaging, Division of Nuclear Medicine, Faculty of Medicine, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (A.F.); (D.S.)
| | - Ferenc Krisztián Kálmán
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (T.C.); (D.S.); (F.K.K.); (O.H.); (I.T.)
| | - Oldamur Hollóczki
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (T.C.); (D.S.); (F.K.K.); (O.H.); (I.T.)
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4+6, D-53115 Bonn, Germany
| | - Anikó Fekete
- Department of Medical Imaging, Division of Nuclear Medicine, Faculty of Medicine, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (A.F.); (D.S.)
| | - Dezső Szikra
- Department of Medical Imaging, Division of Nuclear Medicine, Faculty of Medicine, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (A.F.); (D.S.)
| | - Éva Tóth
- Centre de Biophysique Moléculaire, CNRS, Rue Charles Sadron, CEDEX 2, 45071 Orléans, France;
| | - Imre Tóth
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (T.C.); (D.S.); (F.K.K.); (O.H.); (I.T.)
| | - Gyula Tircsó
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (T.C.); (D.S.); (F.K.K.); (O.H.); (I.T.)
- Correspondence: ; Tel.: +36-52-512-900 (ext. 22374)
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Gold BT, Shao X, Sudduth TL, Jicha GA, Wilcock DM, Seago ER, Wang DJ. Water exchange rate across the blood-brain barrier is associated with CSF amyloid-β 42 in healthy older adults. Alzheimers Dement 2021; 17:2020-2029. [PMID: 33949773 PMCID: PMC8717840 DOI: 10.1002/alz.12357] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 03/19/2021] [Accepted: 04/07/2021] [Indexed: 01/21/2023]
Abstract
INTRODUCTION We tested if water exchange across the blood-brain barrier (BBB), estimated with a noninvasive magnetic resonance imaging (MRI) technique, is associated with cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) and neuropsychological function. METHODS Forty cognitively normal older adults (67-86 years old) were scanned with diffusion-prepared, arterial spin labeling (DP-ASL), which estimates water exchange rate across the BBB (kw ). Participants also underwent CSF draw and neuropsychological testing. Multiple linear regression models were run with kw as a predictor of CSF concentrations and neuropsychological scores. RESULTS In multiple brain regions, BBB kw was positively associated with CSF amyloid beta (Aβ)42 concentration levels. BBB kw was only moderately associated with neuropsychological performance. DISCUSSION Our results suggest that low water exchange rate across the BBB is associated with low CSF Aβ42 concentration. These findings suggest that kw may be a promising noninvasive indicator of BBB Aβ clearance functions, a possibility which should be further tested in future research.
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Affiliation(s)
- Brian T. Gold
- Department of NeuroscienceSanders‐Brown Center on AgingLexingtonKentuckyUSA
- Sanders‐Brown Center on AgingLexingtonKentuckyUSA
- Magnetic Resonance Imaging and Spectroscopy CenterCollege of MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Xingfeng Shao
- Laboratory of FMRI Technology (LOFT)Mark & Mary Stevens Neuroimaging and Informatics InstituteKeck School of MedicineUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | | | - Gregory A. Jicha
- Sanders‐Brown Center on AgingLexingtonKentuckyUSA
- Department of NeurologySanders‐Brown Center on AgingLexingtonKentuckyUSA
| | - Donna M. Wilcock
- Sanders‐Brown Center on AgingLexingtonKentuckyUSA
- Department of PhysiologySanders‐Brown Center on AgingLexingtonKentuckyUSA
| | - Elayna R. Seago
- Department of NeuroscienceSanders‐Brown Center on AgingLexingtonKentuckyUSA
| | - Danny J.J. Wang
- Laboratory of FMRI Technology (LOFT)Mark & Mary Stevens Neuroimaging and Informatics InstituteKeck School of MedicineUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
- Department of NeurologyKeck School of MedicineUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
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Lin Z, Lance E, McIntyre T, Li Y, Liu P, Lim C, Fan H, Tekes A, Cannon A, Casella JF, Lu H. Imaging Blood-Brain Barrier Permeability Through MRI in Pediatric Sickle Cell Disease: A Feasibility Study. J Magn Reson Imaging 2021; 55:1551-1558. [PMID: 34676938 PMCID: PMC9018466 DOI: 10.1002/jmri.27965] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 10/08/2021] [Accepted: 10/14/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Blood-brain barrier (BBB) disruption may lead to endothelium dysfunction and inflammation in sickle cell disease (SCD). However, abnormalities of BBB in SCD, especially in pediatric patients for whom contrast agent administration less than optimal, have not been fully characterized. PURPOSE To examine BBB permeability to water in a group of pediatric SCD participants using a non-invasive magnetic resonance imaging technique. We hypothesized that SCD participants will have increased BBB permeability. STUDY TYPE Prospective cross-sectional. POPULATION Twenty-six pediatric participants (10 ± 1 years, 15F/11M) were enrolled, including 21 SCD participants and 5 sickle cell trait (SCT) participants, who were siblings of SCD patients. FIELD STRENGTH/SEQUENCE 3 T. Water extraction with phase-contrast arterial spin tagging with echo-planer imaging, phase-contrast and T1 -weighted magnetization-prepared rapid acquisition of gradient echo. ASSESSMENT Water extraction fraction (E), BBB permeability-surface area product (PS), cerebral blood flow, hematological measures (hemoglobin, hematocrit, hemoglobin S), neuropsychological scores (including domains of intellectual ability, attention and executive function, academic achievement and adaptive function, and a composite score). Regions of interest were drawn by Z.L. (6 years of experience). STATISTICAL TESTS Wilcoxon rank sum test and chi-square test for group comparison of demographics. Multiple linear regression analysis of PS with diagnostic category (SCD or SCT), hematological measures, and neuropsychological scores. A two-tailed P value of 0.05 or less was considered statistically significant. RESULTS Compared with SCT participants, SCD participants had a significantly higher BBB permeability to water (SCD: 207.0 ± 33.3 mL/100 g/minute, SCT: 171.2 ± 27.2 mL/100 g/minute). SCD participants with typically more severe phenotypes also had a significantly leakier BBB than those with typically milder phenotypes (severe: 217.3 ± 31.7 mL/100 g/minute, mild: 193.3 ± 31.8 mL/100 g/minute). Furthermore, more severe BBB disruption was associated with worse hematological symptoms, including lower hemoglobin concentrations (β = -8.84, 95% confidence interval [CI] [-14.69, -3.00]), lower hematocrits (β = -2.96, 95% CI [-4.84, -1.08]), and higher hemoglobin S fraction (β = 0.77, 95% CI [0.014, 1.53]). DATA CONCLUSION These findings support a potential role for BBB dysfunction in SCD pathogenesis of ischemic injury. LEVEL OF EVIDENCE 2 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Zixuan Lin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Eboni Lance
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, Maryland, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Tiffany McIntyre
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Yang Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peiying Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Chantelle Lim
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hongli Fan
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Aylin Tekes
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Alicia Cannon
- Department of Neuropsychology, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - James F Casella
- Department of Pediatrics, Division of Hematology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hanzhang Lu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
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Hsieh YH, Tang CP, Tseng CW, Lin TL, Leung FW. Computer-Aided Detection False Positives in Colonoscopy. Diagnostics (Basel) 2021; 11:1113. [PMID: 34207226 DOI: 10.3390/diagnostics11061113] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/08/2021] [Accepted: 06/14/2021] [Indexed: 12/24/2022] Open
Abstract
Randomized control trials and meta-analyses comparing colonoscopies with and without computer-aided detection (CADe) assistance showed significant increases in adenoma detection rates (ADRs) with CADe. A major limitation of CADe is its false positives (FPs), ranked 3rd in importance among 59 research questions in a modified Delphi consensus review. The definition of FPs varies. One commonly used definition defines an FP as an activation of the CADe system, irrespective of the number of frames or duration of time, not due to any polypoid or nonpolypoid lesions. Although only 0.07 to 0.2 FPs were observed per colonoscopy, video analysis studies using FPs as the primary outcome showed much higher numbers of 26 to 27 per colonoscopy. Most FPs were of short duration (91% < 0.5 s). A higher number of FPs was also associated with suboptimal bowel preparation. The appearance of FPs can lead to user fatigue. The polypectomy of FPs results in increased procedure time and added use of resources. Re-training the CADe algorithms is one way to reduce FPs but is not practical in the clinical setting during colonoscopy. Water exchange (WE) is an emerging method that the colonoscopist can use to provide salvage cleaning during insertion. We discuss the potential of WE for reducing FPs as well as the augmentation of ADRs through CADe.
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Abstract
We developed a Monte Carlo simulator for diffusion-weighted imaging sequences which displays the motion of water molecules and computes the dynamic phase dispersion due to the applied motion probing gradients. This simulator can be used to validate the analytical equations of diffusion models and understand their limitations due to their approximations. Here, we introduce the software and some specific use cases. The software can be downloaded from the following website: https://www.nirs.qst.go.jp/amr_diag.
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Affiliation(s)
- Yasuhiko Tachibana
- Applied MRI Research, Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences
| | - Tanguy Duval
- NeuroPoly Lab, Institute of Biomedical Engineering
| | - Takayuki Obata
- Applied MRI Research, Department of Molecular Imaging and Theranostics, National Institute of Radiological Sciences
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Kálmán FK, Nagy V, Uzal-Varela R, Pérez-Lourido P, Esteban-Gómez D, Garda Z, Pota K, Mezei R, Pallier A, Tóth É, Platas-Iglesias C, Tircsó G. Expanding the Ligand Classes Used for Mn(II) Complexation: Oxa-aza Macrocycles Make the Difference. Molecules 2021; 26:molecules26061524. [PMID: 33802241 PMCID: PMC7998310 DOI: 10.3390/molecules26061524] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 02/27/2021] [Accepted: 02/28/2021] [Indexed: 12/16/2022] Open
Abstract
We report two macrocyclic ligands based on a 1,7-diaza-12-crown-4 platform functionalized with acetate (tO2DO2A2−) or piperidineacetamide (tO2DO2AMPip) pendant arms and a detailed characterization of the corresponding Mn(II) complexes. The X−ray structure of [Mn(tO2DO2A)(H2O)]·2H2O shows that the metal ion is coordinated by six donor atoms of the macrocyclic ligand and one water molecule, to result in seven-coordination. The Cu(II) analogue presents a distorted octahedral coordination environment. The protonation constants of the ligands and the stability constants of the complexes formed with Mn(II) and other biologically relevant metal ions (Mg(II), Ca(II), Cu(II) and Zn(II)) were determined using potentiometric titrations (I = 0.15 M NaCl, T = 25 °C). The conditional stabilities of Mn(II) complexes at pH 7.4 are comparable to those reported for the cyclen-based tDO2A2− ligand. The dissociation of the Mn(II) chelates were investigated by evaluating the rate constants of metal exchange reactions with Cu(II) under acidic conditions (I = 0.15 M NaCl, T = 25 °C). Dissociation of the [Mn(tO2DO2A)(H2O)] complex occurs through both proton− and metal−assisted pathways, while the [Mn(tO2DO2AMPip)(H2O)] analogue dissociates through spontaneous and proton-assisted mechanisms. The Mn(II) complex of tO2DO2A2− is remarkably inert with respect to its dissociation, while the amide analogue is significantly more labile. The presence of a water molecule coordinated to Mn(II) imparts relatively high relaxivities to the complexes. The parameters determining this key property were investigated using 17O NMR (Nuclear Magnetic Resonance) transverse relaxation rates and 1H nuclear magnetic relaxation dispersion (NMRD) profiles.
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Affiliation(s)
- Ferenc K. Kálmán
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary; (F.K.K.); (V.N.); (Z.G.); (R.M.)
| | - Viktória Nagy
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary; (F.K.K.); (V.N.); (Z.G.); (R.M.)
| | - Rocío Uzal-Varela
- Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Spain; (R.U.-V.); (D.E.-G.)
| | - Paulo Pérez-Lourido
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidade de Vigo, As Lagoas, Marcosende, 36310 Pontevedra, Spain;
| | - David Esteban-Gómez
- Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Spain; (R.U.-V.); (D.E.-G.)
| | - Zoltán Garda
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary; (F.K.K.); (V.N.); (Z.G.); (R.M.)
| | - Kristof Pota
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 West Bowie Street, Fort Worth, TX 76109, USA;
| | - Roland Mezei
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary; (F.K.K.); (V.N.); (Z.G.); (R.M.)
| | - Agnès Pallier
- Centre de Biophysique Moléculaire, CNRS, UPR 4301, Rue Charles-Sadron, CEDEX 2, 45071 Orléans, France;
| | - Éva Tóth
- Centre de Biophysique Moléculaire, CNRS, UPR 4301, Rue Charles-Sadron, CEDEX 2, 45071 Orléans, France;
- Correspondence: (É.T.); (C.P.-I.); (G.T.); Tel.: +33-2-38-25-76-25 (É.T.); +34-881-5597 (C.P.-I.); +36-52-512-900 (ext. 22374) (G.T.)
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Spain; (R.U.-V.); (D.E.-G.)
- Correspondence: (É.T.); (C.P.-I.); (G.T.); Tel.: +33-2-38-25-76-25 (É.T.); +34-881-5597 (C.P.-I.); +36-52-512-900 (ext. 22374) (G.T.)
| | - Gyula Tircsó
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary; (F.K.K.); (V.N.); (Z.G.); (R.M.)
- Correspondence: (É.T.); (C.P.-I.); (G.T.); Tel.: +33-2-38-25-76-25 (É.T.); +34-881-5597 (C.P.-I.); +36-52-512-900 (ext. 22374) (G.T.)
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Wang G, Angelovski G. Macrocyclic Chelates Bridged by a Diaza-Crown Ether: Towards Multinuclear Bimodal Molecular Imaging Probes. Molecules 2020; 25:E5019. [PMID: 33138207 DOI: 10.3390/molecules25215019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 12/02/2022] Open
Abstract
Bridged polymacrocyclic ligands featured by structurally different cages offer the possibility of coordinating multiple trivalent lanthanide ions, giving rise to the exploitation of their different physicochemical properties, e.g., multimodal detection for molecular imaging purposes. Intrigued by the complementary properties of optical and MR-based image capturing modalities, we report the synthesis and characterization of the polymetallic Ln(III)-based chelate comprised of two DOTA-amide-based ligands (DOTA—1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) bridged via 1,10-diaza-18-crown-6 (DA18C6) motif. The DOTA-amide moieties and the DA18C6 were used to chelate two Eu(III) ions and one Tb(III) ion, respectively, resulting in a multinuclear heterometallic complex Eu2LTb. The bimetallic complex without Tb(III), Eu2L, displayed a strong paramagnetic chemical exchange saturation transfer (paraCEST) effect. Notably, the luminescence spectra of Eu2LTb featured mixed emission including the characteristic bands of Eu(III) and Tb(III). The advantageous features of the complex Eu2LTb opens new possibilities for the future design of bimodal probes and their potential applicability in CEST MR and optical imaging.
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Yen AW, Leung JW, Wilson MD, Leung FW. Underwater versus conventional endoscopic resection of nondiminutive nonpedunculated colorectal lesions: a prospective randomized controlled trial (with video). Gastrointest Endosc 2020; 91:643-654.e2. [PMID: 31628954 PMCID: PMC7039760 DOI: 10.1016/j.gie.2019.09.039] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 09/27/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND AND AIMS Incomplete resection of colorectal neoplasia decreases the efficacy of colonoscopy. Conventional resection (CR) of polyps, performed in a gas-distended colon, is the current standard, but incomplete resection rates of approximately 2% to 30% for nondiminutive (>5 mm), nonpedunculated lesions are reported. Underwater resection (UR) is a novel technique. The aim of this study was to determine the incomplete resection rates of colorectal lesions removed by UR versus CR. METHODS In a randomized controlled trial, patients with small (6-9 mm) and large (≥10 mm) nonpedunculated lesions were assigned to CR (gas-distended lumen) or UR (water-filled, gas-excluded lumen). Small lesions in both arms were removed with a dedicated cold snare. For CR, large lesions were removed with a hot snare after submucosal injection. For UR, large lesions were removed with a hot snare without submucosal injection. Four-quadrant biopsy samples around the resection sites were used to evaluate for incomplete resection. RESULTS Four hundred sixty-two eligible polyps (248 UR vs 214 CR) from 255 patients were removed. Incomplete resection rates for UR and CR were low and did not differ (2% vs 1.9%, P = .91). UR was performed significantly faster for lesions ≥10 mm in size (10-19 mm, 2.9 minutes vs 5.6 minutes, P < .0001); ≥20 mm, 7.3 minutes vs 9.5 minutes, P = .015). CONCLUSIONS Low incomplete resection rates are achievable with UR and CR. UR is effective and safe with the advantage of faster resection and potential cost savings for removal of larger (≥10 mm) lesions by avoiding submucosal injection. As an added approach, UR has potential to improve the cost-effectiveness of colonoscopy by increasing efficiency and reducing cost while maintaining quality. (Clinical trial registration number: NCT02889679.).
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Affiliation(s)
- Andrew W. Yen
- Sacramento Veterans Affairs Medical Center, VA Northern California Health Care System, Division of Gastroenterology, Mather, CA 95655,University of California Davis School of Medicine, Sacramento, CA 95817
| | - Joseph W. Leung
- Sacramento Veterans Affairs Medical Center, VA Northern California Health Care System, Division of Gastroenterology, Mather, CA 95655,University of California Davis School of Medicine, Sacramento, CA 95817
| | - Machelle D. Wilson
- Clinical and Translational Science Center, Department of Public Health Sciences, Division of Biostatistics, University of California Davis, Sacramento CA 95817
| | - Felix W. Leung
- Sepulveda Ambulatory Care Center, VA Greater Los Angeles Healthcare System, Division of Gastroenterology, North Hills, CA 91343,David Geffen School of Medicine at UCLA, Los Angeles, CA 90095
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Aziz M, Sharma S, Fatima R, Lee-Smith W, Sodeman T, Nawras A, Adler DG. How to increase proximal adenoma detection rate: a meta-analysis comparing water exchange, water immersion and air/CO 2 insufflation methods for colonoscopy. Ann Gastroenterol 2020; 33:178-186. [PMID: 32127739 PMCID: PMC7049237 DOI: 10.20524/aog.2020.0459] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 12/30/2019] [Indexed: 12/12/2022] Open
Abstract
Background Recent meta-analyses have demonstrated a higher adenoma detection rate using the water exchange method (WE), compared to water immersion (WI) and air/CO2 insufflation (ACI). Proximal adenomas have a high miss rate owing to their location and appearance. We performed a systematic review and meta-analysis of studies comparing the WE and WI methods to the ACI method, with a primary focus on proximal adenoma detection rate. Methods The following databases were searched for our systematic review: Medline, Embase, Cochrane Library, CINAHL, and Web of Sciences. We included both randomized controlled trials and cohort studies. The primary outcome was proximal adenoma detection rate, and secondary outcomes were right adenoma detection rate and cecal intubation rate. Results A total of 12 studies (17 arms) with 5660 patients (2260 ACI, 2281 WE, and 1119 WI) were included. A higher proximal adenoma detection rate (risk ratio [RR] 1.30, 95% confidence interval [CI] 1.11-1.53; P=0.001) and right adenoma detection rate (RR 1.43, 95%CI 1.19-1.71; P≤0.001; I2=0%) were noted for the WE group compared to the ACI group. The WI group did not demonstrate a better detection rate of proximal or right adenomas. Conclusions The water exchange method for colonoscopy holds promise and should be encouraged in the clinical setting to increase proximal and right adenoma detection rates. This will in turn decrease the incidence of colorectal cancer.
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Affiliation(s)
- Muhammad Aziz
- Department of Internal Medicine, University of Toledo Medical Center, Toledo, Ohio (Muhammad Aziz, Sachit Sharma, Rawish Fatima)
| | - Sachit Sharma
- Department of Internal Medicine, University of Toledo Medical Center, Toledo, Ohio (Muhammad Aziz, Sachit Sharma, Rawish Fatima)
| | - Rawish Fatima
- Department of Internal Medicine, University of Toledo Medical Center, Toledo, Ohio (Muhammad Aziz, Sachit Sharma, Rawish Fatima)
| | - Wade Lee-Smith
- Department of Internal Medicine, University of Toledo Libraries, Toledo, Ohio (Wade Lee-Smith)
| | - Thomas Sodeman
- Department of Gastroenterology, University of Toledo Medical Center, Toledo, Ohio (Thomas Sodeman, Ali Nawras)
| | - Ali Nawras
- Department of Gastroenterology, University of Toledo Medical Center, Toledo, Ohio (Thomas Sodeman, Ali Nawras)
| | - Douglas G Adler
- Department of Gastroenterology, University of Utah, Salt Lake City, Utah (Douglas G. Adler), USA
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29
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Hsieh YH, Tseng CW, Koo M, Leung FW. Feasibility of sedation on demand in Taiwan using water exchange and air insufflation: A randomized controlled trial. J Gastroenterol Hepatol 2020; 35:256-262. [PMID: 31420895 DOI: 10.1111/jgh.14839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/08/2019] [Accepted: 08/12/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIM Completion of colonoscopy without sedation eliminates sedation cost and complications. Reported in the United States and Europe, on-demand sedation is not routine practice in Taiwan. Water exchange (WE), characterized by infusion and nearly complete removal of infused water during insertion, reduces insertion pain compared to air insufflation (AI) during colonoscopy. We evaluated the feasibility of on-demand sedation in Taiwan. In a randomized controlled trial of WE vs AI colonoscopy, we also aimed to determine if WE augmented the implementation by reducing insertion pain and decreasing sedation requirement. METHODS This prospective patient-blinded study randomized patients to AI or WE (75 patients/group) to aid insertion. The primary outcome was the proportion of patients completing without sedation. RESULTS In the AI and WE groups, 76.0% and 93.3% (P = 0.006) completed without need for sedation, respectively. The WE group had lower insertion pain score (mean [SD]) (4.0 [2.9] vs 2.1 [2.6], P < 0.001), lower doses of propofol (25.7 [52.7] mg vs 9.1 [35.6] mg, P = 0.012), and less time in the recovery room (3.4 [7.4] vs 1.5 [5.5], P = 0.027) than the AI group. Patient satisfaction scores and willingness to repeat if needed in the future were similar. CONCLUSION On-demand sedation was feasible in Taiwan. The completion rate without sedation was high in patients (76.0% with standard AI) open to the option (no prior intent to receive the standard of full or minimal sedation). WE augmented the implementation by reducing insertion pain and decreasing sedation requirement without adversely affecting patient satisfaction or willingness to repeat.
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Affiliation(s)
- Yu-Hsi Hsieh
- Division of Gastroenterology, Department of Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.,School of Medicine, Buddhist Tzu Chi University, Hualien, Taiwan
| | - Chih-Wei Tseng
- Division of Gastroenterology, Department of Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.,School of Medicine, Buddhist Tzu Chi University, Hualien, Taiwan
| | - Malcolm Koo
- Graduate Institute of Long-term Care, Tzu Chi University of Science and Technology, Hualien, Taiwan.,Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Felix W Leung
- Veterans Affairs Greater Los Angeles Healthcare System, Sepulveda Ambulatory Care Center, North Hill, California, USA.,David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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Abstract
Introduction: Among the Gastrointestinal (GI) Endoscopy Editorial Board top 10 topics in advances in endoscopy in 2018, water exchange colonoscopy and artificial intelligence were both considered important advances. Artificial intelligence holds the potential to increase and water exchange significantly increases adenoma detection.Areas covered: The authors searched MEDLINE (1998-2019) using the following medical subject terms: water-aided, water-assisted and water exchange colonoscopy, adenoma, artificial intelligence, deep learning, computer-assisted detection, and neural networks. Additional related studies were manually searched from the reference lists of publications. Only fully published journal articles in English were reviewed. The latest date of the search was Aug10, 2019. Artificial intelligence, machine learning, and deep learning contribute to the promise of real-time computer-aided detection diagnosis. By emphasizing near-complete suction of infused water during insertion, water exchange provides salvage cleaning and decreases cleaning-related multi-tasking distractions during withdrawal, increasing adenoma detection. The review will address how artificial intelligence and water exchange can complement each other in improving adenoma detection during colonoscopy.Expert opinion: In 5 years, research on artificial intelligence will likely achieve real-time application and evaluation of factors contributing to quality colonoscopy. Better understanding and more widespread use of water exchange will be possible.
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Affiliation(s)
- Yu-Hsi Hsieh
- Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.,School of Medicine, Tzu Chi University, Hualien City, Taiwan
| | - Felix W Leung
- Sepulveda Ambulatory Care Center, Veterans Affairs Greater Los Angeles Healthcare System, North Hills, CA, USA.,David Geffen School of Medicine, at University of California at Los Angeles, Los Angeles, CA, USA
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Zhang J, Kim SG. Estimation of cellular-interstitial water exchange in dynamic contrast enhanced MRI using two flip angles. NMR Biomed 2019; 32:e4135. [PMID: 31348580 PMCID: PMC6817382 DOI: 10.1002/nbm.4135] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 06/11/2019] [Accepted: 06/17/2019] [Indexed: 05/10/2023]
Abstract
PURPOSE To investigate the feasibility of using multiple flip angles in dynamic contrast enhanced (DCE) MRI to reduce the uncertainty in estimation of intracellular water lifetime (τi ). METHODS Numerical simulation studies were conducted to assess the uncertainty in estimation of τi using dynamic contrast enhanced MRI with one or two flip angles. In vivo experiments with a murine brain tumor model were conducted at 7T using two flip angles. The in vivo data were used to compare τi estimation using the single-flip-angle (SFA) protocol with that using the double-flip-angle (DFA) protocol. Data analysis was conducted using the two-compartment exchange model combined with the three-site-two-exchange model for water exchange. RESULTS In the numerical simulation studies with a range of contrast kinetic parameters and signal-to-noise ratio = 20, the median bias of τi estimation decreased from 72 ms with SFA to 65 ms with DFA, and the corresponding median inter-quartile range reduced from 523 ms to 156 ms. In the in vivo studies, τi estimation with SFA was not successful in most voxels in the tumors, as the estimated τi values reached the upper limit of the parameter range (2 s). In contrast, the estimated τi values with DFA were mostly between 0.2 and 1.5 s and homogeneously distributed spatially across the tumor. The τi estimation with DFA was less sensitive to arterial input function scaling but more sensitive to pre-contrast T1 than the other contrast kinetic parameters. CONCLUSION This study results demonstrate the feasibility of using multiple flip angles to encode the post-contrast time-intensity curve with different weighting of water exchange effect to reduce the uncertainty in τi estimation.
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Affiliation(s)
- Jin Zhang
- Center for Biomedical Imaging (CBI), Center for Advanced Imaging Innovation and Research (CAIR), Department of Radiology, New York University School of Medicine, New York, NY, United States
| | - Sungheon Gene Kim
- Center for Biomedical Imaging (CBI), Center for Advanced Imaging Innovation and Research (CAIR), Department of Radiology, New York University School of Medicine, New York, NY, United States
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32
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Smith EN, McCullagh JSO, Ratcliffe RG, Kruger NJ. Limitations of Deuterium-Labelled Substrates for Quantifying NADPH Metabolism in Heterotrophic Arabidopsis Cell Cultures. Metabolites 2019; 9:E205. [PMID: 31569392 DOI: 10.3390/metabo9100205] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 09/19/2019] [Accepted: 09/26/2019] [Indexed: 01/21/2023] Open
Abstract
NADPH is the primary source of cellular reductant for biosynthesis, and strategies for increasing productivity via metabolic engineering need to take account of the requirement for reducing power. In plants, while the oxidative pentose phosphate pathway is the most direct route for NADPH production in heterotrophic tissues, there is increasing evidence that other pathways make significant contributions to redox balance. Deuterium-based isotopic labelling strategies have recently been developed to quantify the relative production of NADPH from different pathways in mammalian cells, but the application of these methods to plants has not been critically evaluated. In this study, LC-MS was used to measure deuterium incorporation into metabolites extracted from heterotrophic Arabidopsis cell cultures grown on [1-2H]glucose or D2O. The results show that a high rate of flavin-enzyme-catalysed water exchange obscures labelling of NADPH from deuterated substrates and that this exchange cannot be accurately accounted for due to exchange between triose- and hexose-phosphates. In addition, the duplication of NADPH generating reactions between subcellular compartments can confound analysis based on whole cell extracts. Understanding how the structure of the metabolic network affects the applicability of deuterium labelling methods is a prerequisite for development of more effective flux determination strategies, ensuring data are both quantitative and representative of endogenous biological processes.
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Abstract
The goal of diagnostic colonoscopy is to achieve procedural completion while maximising effectiveness, patient acceptance and safety. In recent years, international interest in water-assisted colonoscopy (WAC) has been steadily gathering pace. A plethora of high-quality randomised controlled trials and meta-analyses now offer incontrovertible evidence into the benefits of WAC, both for the endoscopist and the patient. Despite this, uptake of WAC within the UK has been limited, with the lack of educational resources representing a significant barrier. This practical step-by-step guide is aimed at both existing practitioners and trainees, with a view to promoting familiarity with WAC and potentially for incorporation into daily practice which may ultimately have a positive effect on quality of colonoscopy and patient experience.
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Affiliation(s)
- Keith Siau
- Department of Gastroenterology, Dudley Group Hospitals NHS Foundation Trust, Dudley, UK
- Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Iosif Beintaris
- Department of Gastroenterology, North Tees and Hartlepool NHS Foundation Trust, Stockton-on-Tees, UK
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34
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Leung JW, Yen AW, Jia H, Opada C, Melnik A, Atkins J, Feller C, Wilson MD, Leung FW. A prospective RCT comparing combined chromoendoscopy with water exchange (CWE) vs water exchange (WE) vs air insufflation (AI) in adenoma detection in screening colonoscopy. United European Gastroenterol J 2019; 7:477-487. [PMID: 31065365 DOI: 10.1177/2050640619832196] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 01/22/2019] [Indexed: 12/15/2022] Open
Abstract
Background A low adenoma detection rate (ADR) increases risks of interval cancers (ICs). Proximal colon flat polyps, e.g. serrated lesions (SLs), are difficult to find. Missed proximal colon flat lesions likely contribute to IC. Aims We compared chromoendoscopy with water exchange (CWE), water exchange (WE) and air insufflation (AI) in detecting adenomas in screening colonoscopy. Methods After split-dose preparation, 480 veterans were randomized to AI, WE and CWE. Results Primary outcome of proximal ADR (55.6% vs 53.4% vs 52.2%, respectively) were similar in all groups. Adenoma per colonoscopy (APC) and adenoma per positive colonoscopy (APPC) were comparable. Detection rate of proximal colon SLs was significantly higher for CWE and WE than AI (26.3%, 23.6% and 11.3%, respectively, p = 0.002). Limitations: single operator; SLs only surrogate markers of but not IC. Conclusions When an endoscopist achieves high-quality AI examinations with overall ADR twice (61.6%) the recommended standard (30%), use of WE and CWE does not produce further improvement in proximal or overall ADR. Comparable APC and APPC confirm equivalent withdrawal inspection techniques. WE alone is sufficient to significantly improve detection of proximal SLs. The impact of increased detection of proximal SLs by WE on prevention of IC deserves to be studied. This study is registered at ClinicalTrial.gov (NCT#01607255).
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Affiliation(s)
- J W Leung
- Section of Gastroenterology, Sacramento Veteran Affairs Medical Center, Veteran Affairs Northern California Health Care System (VANCHCS), Mather, CA, USA.,Division of Gastroenterology and Hepatology, University of California, Davis School of Medicine, Sacramento, CA, USA
| | - A W Yen
- Section of Gastroenterology, Sacramento Veteran Affairs Medical Center, Veteran Affairs Northern California Health Care System (VANCHCS), Mather, CA, USA
| | - H Jia
- Department of Gastroenterology, Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - C Opada
- Section of Gastroenterology, Sacramento Veteran Affairs Medical Center, Veteran Affairs Northern California Health Care System (VANCHCS), Mather, CA, USA
| | - A Melnik
- Section of Gastroenterology, Sacramento Veteran Affairs Medical Center, Veteran Affairs Northern California Health Care System (VANCHCS), Mather, CA, USA
| | - J Atkins
- Section of Gastroenterology, Sacramento Veteran Affairs Medical Center, Veteran Affairs Northern California Health Care System (VANCHCS), Mather, CA, USA
| | - C Feller
- Section of Gastroenterology, Sacramento Veteran Affairs Medical Center, Veteran Affairs Northern California Health Care System (VANCHCS), Mather, CA, USA
| | - M D Wilson
- Clinical and Translational Science Center, Department of Public Health Sciences, Division of Biostatistics, University of California, Davis, Sacramento, CA, USA
| | - F W Leung
- Sepulveda Ambulatory Care Center, Veteran Affairs Greater Los Angeles Healthcare System (VAGLAHS) and David Geffen School of Medicine at UCLA, North Hills, CA, USA
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35
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Fang D, Mei T, Röll A, Hölscher D. Water Transfer Between Bamboo Culms in the Period of Sprouting. Front Plant Sci 2019; 10:786. [PMID: 31249586 PMCID: PMC6582707 DOI: 10.3389/fpls.2019.00786] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 05/29/2019] [Indexed: 05/14/2023]
Abstract
Bamboo culms are connected to neighboring culms via rhizomes, which enable resource exchange between culms. We assessed water transfer between established and neighboring, freshly sprouted culms by thermal dissipation probes (TDP) inserted into culms and the connecting rhizome. During the early phase of sprouting, highest sap flux densities in freshly sprouted culms were observed at night, whereas neighboring established culms had high sap flux densities during daytime. After leaf flushing on freshly sprouted culms, the nighttime peaks disappeared and culms switched to the diurnal sap flux patterns with daytime maxima as observed in established culms. TDP in rhizomes indicated water flowing from the established to the freshly sprouted culms. When the established culms of a clump were cut, freshly sprouted culms without leaves reduced sap flux densities rates by 79%. Our findings thus suggest that bamboos exchange water via rhizomes and that nighttime fluxes are highly important for the support of freshly sprouted culms. The (water) resource support may facilitate the very fast growth of the bamboo shoots, and enable the colonizing of new places.
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Affiliation(s)
- Dongming Fang
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin’an, China
- Tropical Silviculture and Forest Ecology, University of Göttingen, Göttingen, Germany
- *Correspondence: Dongming Fang,
| | - Tingting Mei
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin’an, China
- Tropical Silviculture and Forest Ecology, University of Göttingen, Göttingen, Germany
| | - Alexander Röll
- Tropical Silviculture and Forest Ecology, University of Göttingen, Göttingen, Germany
| | - Dirk Hölscher
- Tropical Silviculture and Forest Ecology, University of Göttingen, Göttingen, Germany
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Hsieh YH, Koo M, Tseng CW, Yang HW, Leung FW. Reduction of multitasking distractions underlies the higher adenoma detection rate of water exchange compared to air insufflation - blinded analysis of withdrawal phase videos. United European Gastroenterol J 2018; 7:230-238. [PMID: 31080608 DOI: 10.1177/2050640618817105] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 11/09/2018] [Indexed: 01/15/2023] Open
Abstract
Background Experts have hypothesized that a reduction of multitasking distractions and improved bowel cleanliness can explain why insertion water exchange enhances adenoma detection rate. Objective The purpose of this study was to test the role of both distractions during withdrawal and bowel cleanliness in enhancing adenoma detection rate using coded video records of colonoscopy. Methods The withdrawal phase of videos of 299 consecutive colonoscopies from two randomized controlled trials comparing water exchange versus air insufflation at a regional hospital in Taiwan were coded. The primary outcome was distractions; activities that preclude full attention being paid to inspection of the mucosa for polyps. A single blinded reviewer collected the data. Results There were significant agreements in inter-rater reliability indexes. Compared to air insufflation, water exchange had significantly fewer distractions; higher diagnostic yield (intervention time and number), adenoma detection rate, and Boston Bowel Preparation Scale score. Water exchange had a higher withdrawal technique score (predominantly adequacy of cleaning). The association between increased adenoma detection rate and water exchange was mediated by the number of distractions and withdrawal time, but not the Boston Bowel Preparation Scale score. Conclusion The speculation by experts that a reduction of multitasking distractions underlies the significantly higher adenoma detection rate of water exchange is supported by the current study. Increased bowel cleanliness did not contribute to the increased adenoma detection rate by use of water exchange.
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Affiliation(s)
- Yu-Hsi Hsieh
- Division of Gastroenterology, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.,School of Medicine, Buddhist Tzu Chi University, Hualien, Taiwan
| | - Malcolm Koo
- Graduate Institute of Long-term Care, Tzu Chi University of Science and Technology, Hualien, Taiwan.,Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
| | - Chih-Wei Tseng
- Division of Gastroenterology, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.,School of Medicine, Buddhist Tzu Chi University, Hualien, Taiwan
| | - Hsiu-Wen Yang
- Division of Gastroenterology, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan
| | - Felix W Leung
- Sepulveda Ambulatory Care Center, Veterans Affairs Greater Los Angeles Healthcare System, North Hill, USA.,David Geffen School of Medicine at UCLA, Los Angeles, USA
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37
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Abstract
BACKGROUND/AIMS To compare water exchange (WE) method with conventional air insufflation (AI) method for colonoscopy, evaluating the technical quality, screening efficacy, and patients' acceptance. MATERIALS AND METHODS Electronic databases were systematically searched for randomized controlled trials comparing WE colonoscopy with AI colonoscopy. The pooled data of procedure-associated and patient-related outcomes were assessed, using the weighted mean difference (WMD) with 95% confidence interval (CI) for continuous variables and relative risk (RR) with 95% CI for dichotomous variables, respectively. RESULTS A total of 13 studies involving 7056 patients were included. The cecum intubation rate was similar between WE and AI methods (RR = 1.01, 95% CI = 0.99-1.02,P = 0.37); however, a significantly longer cecum intubation time was shown in WE group (WMD = 1.56, 95% CI = 0.75-2.37,P = 0.002). Compared with AI, WE was associated with a higher risk of adenoma detection rate (ADR) (RR = 1.28, 95% CI = 1.18-1.38,P < 0.00001) and polyp detection rate (PDR) (RR = 1.30, 95% CI = 1.21-1.39,P < 0.00001). Patients in WE group experienced significantly less maximum pain score (WMD = -1.99, 95% CI = -2.68 to -1.30,P < 0.00001) and less requested on-demand sedation (RR = 0.58, 95% CI = 0.44-0.77,P = 0.0002). Likewise, they also experienced less abdominal compression (RR = 0.62, 95% CI = 0.51-0.74,P < 0.00001) and reposition (RR = 0.74, 95% CI = 0.63-0.86,P = 0.0001). Moreover, patients' willingness to repeat colonoscopy was significantly greater for WE (RR = 1.14, 95% CI = 1.07-1.21,P < 0.0001). CONCLUSION This meta-analysis confirmed that WE method could significantly increase ADR/PDR and improve patients' acceptance of colonoscopy, while reducing the degree of pain and minimize the need for on-demand sedation and adjunct maneuvers, despite requiring more cecal intubation time.
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Affiliation(s)
- Yang Liu
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Qing-Ke Huang
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Xiu-Li Dong
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Piao-Piao Jin
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
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Bai R, Springer CS, Plenz D, Basser PJ. Brain active transmembrane water cycling measured by MR is associated with neuronal activity. Magn Reson Med 2018; 81:1280-1295. [PMID: 30194797 DOI: 10.1002/mrm.27473] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 07/04/2018] [Accepted: 07/09/2018] [Indexed: 02/02/2023]
Abstract
PURPOSE fMRI is widely used to study brain activity. Unfortunately, conventional fMRI methods assess neuronal activity only indirectly, through hemodynamic coupling. Here, we show that active, steady-state transmembrane water cycling (AWC) could serve as a basis for a potential fMRI mechanism for direct neuronal activity detection. METHODS AWC and neuronal actitivity in rat organotypic cortical cultures were simultaneously measured with a hybrid MR-fluorescence system. Perfusion with a paramagnetic MRI contrast agent, Gadoteridol, allows NMR determination of the kinetics of transcytolemmal water exchange. Changes in intracellular calcium concentration, [Cai 2+ ] were used as a proxy of neuronal activity and were monitored by fluorescence imaging. RESULTS When we alter neuronal activity by titrating with extracellular [K+ ] near the normal value, we see an AWC response resembling Na+ -K+ -ATPase (NKA) Michaelis-Menten behavior. When we treat with the voltage-gated sodium channel inhibitor, or with an excitatory postsynaptic inhibitor cocktail, we see AWC decrease by up to 71%. AWC was found also to be positively correlated with the basal level of spontaneous activity, which varies in different cultures. CONCLUSIONS These results suggest that AWC is associated with neuronal activity and NKA activity is a major contributor in coupling AWC to neuronal activity. Although AWC comprises steady-state, homeostatic transmembrane water exchange, our analysis also yields a simultaneous measure of the average cell volume, which reports any slower net transmembrane water transport.
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Affiliation(s)
- Ruiliang Bai
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China.,Section on Quantitative Imaging and Tissue Sciences, DIBGI, NICHD, National Institutes of Health, Bethesda, Maryland
| | - Charles S Springer
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, Oregon
| | - Dietmar Plenz
- Section on Critical Brain Dynamics, LSN, NIMH, National Institutes of Health, Bethesda, Maryland
| | - Peter J Basser
- Section on Quantitative Imaging and Tissue Sciences, DIBGI, NICHD, National Institutes of Health, Bethesda, Maryland
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Abstract
Background/Aims Recently, water exchange (WE) instead of water immersion (WI) for colonoscopy has been proposed to decrease pain and improve adenoma detection rate (ADR). This systematic review and meta-analysis is conducted to assess whether WE is superior to WI based on the published randomized controlled trials (RCTs). Materials and Methods We searched studies from PubMed, Cochrane Central Register of Controlled Trials, EMBASE, and MEDLINE. Only RCTs were eligible for our study. The pooled risk ratios (RRs), pooled mean difference (MD), and pooled 95% confidence intervals (CIs) were calculated by using the fixed-effects model or random-effects model based on heterogeneity. Results Five RCTs consisting of 2229 colonoscopies were included in this study. WE was associated with a significantly higher ADR than WI (RR = 1.18; CI = 1.05-1.32; P = 0.004), especially in right colon (RR = 1.31; CI = 1.07-1.61; P = 0.01). Compared with WI, WE was confirmed with lower pain score, higher Boston Bowel Preparation Scale score, but more infused water during insertion. There was no statistical difference between WE and WI in cecal intubation rate and the number of patients who had willingness to repeat the examination. Furthermore, both total procedure time and cecal intubation time in WE were significantly longer than that in WI (MD = 2.66; CI = 1.42-3.90; P < 0.0001; vs MD = 4.58; CI = 4.01-5.15; P < 0.0001). Conclusions This meta-analysis supports the hypothesis that WE is superior to WI in improving ADR, attenuating insertion pain and providing better bowel cleansing, but inferior in time and consumption of infused water consumption during insertion.
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Affiliation(s)
- Zhihao Chen
- Department of Endoscopy, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, People's Republic of China
| | - Zhengqi Li
- Department of Endoscopy, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, People's Republic of China
| | - Xinying Yu
- Department of Endoscopy, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, People's Republic of China
| | - Guiqi Wang
- Department of Endoscopy, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, People's Republic of China
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Shi X, Tian D, Ye X, Wu Q, Pan Y, Yang Z, Fan D. Is water exchange superior to water immersion in detecting adenomas during colonoscopies? Results from a Bayesian network meta-analysis. Oncotarget 2018; 9:30679-30693. [PMID: 30093978 PMCID: PMC6078142 DOI: 10.18632/oncotarget.25504] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 05/08/2018] [Indexed: 12/13/2022] Open
Abstract
AIM Water-assisted colonoscopy (water exchange [WE] and water immersion [WI]) has been shown to improve the adenoma detection rate. However, few studies have compared these two methods head-to-head. Thus, we conducted a network meta-analysis to integrate both direct and indirect evidence comparing the effectiveness of these two procedures. METHOD We searched PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials for original papers and abstracts published up to March 2018. Randomized controlled trials (RCTs) reporting data in accordance with the eligibility criteria were included in this study. We performed a Bayesian random effects network meta-analysis with mixed comparisons. RESULTS Twenty-nine studies (n = 11464 patients) including 6 direct and 23 indirect comparisons were included in this network meta-analysis. There was a statistically significant difference in the efficacy of adenoma detection when WE was compared with WI (risk ratio [RR]: 1.2, 95% credible interval [CrI]: 1.1-1.3), air insufflation (AI; RR: 1.3, 95% CrI: 1.1-1.4), and carbon dioxide (CO2) insufflation (RR: 1.2, 95% CrI: 1.1-1.5). The different methods were ranked in order from the most to least effective in adenoma detection as follows: WE, WI, AI, and CO2. Moreover, although there were no significant differences in pain scores, willingness to repeat, caecal intubation rate, or total procedure time between WI and WE colonoscopy, WE required a longer caecal intubation time than WI. CONCLUSION This network meta-analysis supposes that WE may be superior to WI in detecting adenomas during colonoscopies without affecting other technical features or patient acceptance.
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Affiliation(s)
- Xin Shi
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi’an, China
| | - Dan Tian
- Office of Educational Administration, Fourth Military Medical University, Xi’an, China
| | - Xiaofei Ye
- Department of Health Statistics, Second Military Medical University, Shanghai, China
| | - Qiong Wu
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi’an, China
| | - Yanglin Pan
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi’an, China
| | - Zhiping Yang
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi’an, China
| | - Daiming Fan
- State Key Laboratory of Cancer Biology, National Clinical Research Center for Digestive Diseases and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi’an, China
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Zhang W, Martinelli J, Peters JA, van Hengst JM, Bouwmeester H, Kramer E, Bonnet CS, Szeremeta F, Tóth É, Djanashvili K. Surface PEG Grafting Density Determines Magnetic Relaxation Properties of Gd-Loaded Porous Nanoparticles for MR Imaging Applications. ACS Appl Mater Interfaces 2017; 9:23458-23465. [PMID: 28657291 PMCID: PMC5520100 DOI: 10.1021/acsami.7b05912] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 06/28/2017] [Indexed: 06/01/2023]
Abstract
Surface PEGylation of nanoparticles designed for biomedical applications is a common and straightforward way to stabilize the materials for in vivo administration and to increase their circulation time. This strategy becomes less trivial when MRI active porous nanomaterials are concerned as their function relies on water/proton-exchange between the pores and bulk water. Here we present a comprehensive study on the effects of PEGylation on the relaxometric properties of nanozeolite LTL (dimensions of 20 × 40 nm) ion-exchanged with paramagnetic GdIII ions. We evidence that as long as the surface grafting density of the PEG chains does not exceed the "mushroom" regime (conjugation of up to 6.2 wt % of PEG), Gd-LTL retains a remarkable longitudinal relaxivity (38 s-1 mM-1 at 7 T and 25 °C) as well as the pH-dependence of the longitudinal and transverse relaxation times. At higher PEG content, the more compact PEG layer (brush regime) limits proton/water diffusion and exchange between the interior of LTL and the bulk, with detrimental consequences on relaxivity. Furthermore, PEGylation of Gd-LTL dramatically decreases the leakage of toxic GdIII ions in biological media and in the presence of competing anions, which together with minimal cytotoxicity renders these materials promising probes for MRI applications.
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Affiliation(s)
- Wuyuan Zhang
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Jonathan Martinelli
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Joop A. Peters
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Jacob M.A. van Hengst
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Hans Bouwmeester
- RIKILT Wageningen Research, Akkermaalsbos 2, 6708WB Wageningen, The Netherlands
- Division
of Toxicology, Wageningen University, Stippeneng 4, 6708WE Wageningen, The Netherlands
| | - Evelien Kramer
- RIKILT Wageningen Research, Akkermaalsbos 2, 6708WB Wageningen, The Netherlands
| | - Célia S. Bonnet
- Centre de Biophysique Moléculaire, CNRS, Rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - Frédéric Szeremeta
- Centre de Biophysique Moléculaire, CNRS, Rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - Éva Tóth
- Centre de Biophysique Moléculaire, CNRS, Rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - Kristina Djanashvili
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
- Centre de Biophysique Moléculaire, CNRS, Rue Charles Sadron, 45071 Orléans Cedex 2, France
- Le Studium, Loire Valley Institute
for Advanced Studies, 1 Rue Dupanloup, 45000 Orléans, France
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Wilson GJ, Springer CS, Bastawrous S, Maki JH. Human whole blood 1 H 2 O transverse relaxation with gadolinium-based contrast reagents: Magnetic susceptibility and transmembrane water exchange. Magn Reson Med 2016; 77:2015-2027. [PMID: 27297589 DOI: 10.1002/mrm.26284] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/31/2016] [Accepted: 04/29/2016] [Indexed: 02/02/2023]
Abstract
PURPOSE To characterize transverse relaxation in oxygenated whole blood with extracellular gadolinium-based contrast reagents by experiment and simulation. METHODS Experimental measurements of transverse 1 H2 O relaxation from oxygenated whole human blood and plasma were made at 1.5 and 3.0 Tesla. Spin-echo refocused and free-induction decays are reported for blood and plasma samples containing four different contrast reagents (gadobenate, gadoteridol, gadofosveset, and gadobutrol), each present at concentrations ranging from 1 to 18 mM (i.e., mmol (contrast reagent (CR))/L (blood)). Monte Carlo simulations were conducted to ascertain the molecular mechanisms underlying relaxation. These consisted of random walks of water molecules in a large ensemble of randomly oriented erythrocytes. Bulk magnetic susceptibility (BMS) differences between the extra- and intracellular compartments were taken into account. All key parameters for these simulations were taken from independent published measurements: they include no adjustable variables. RESULTS Transverse relaxation is much more rapid in whole blood than in plasma, and the large majority of this dephasing is reversible by spin echo. Agreement between the experimental data and simulated results is remarkably good. CONCLUSION Extracellular field inhomogeneities alone make very small contributions, whereas the orientation-dependent BMS intracellular resonance frequencies lead to the majority of transverse dephasing. Equilibrium exchange of water molecules between the intra- and extracellular compartments plays a significant role in transverse dephasing. Magn Reson Med 77:2015-2027, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
| | - Charles S Springer
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, Oregon, USA
| | - Sarah Bastawrous
- Radiology, University of Washington, Seattle, Washington, USA.,Radiology, Puget Sound VA Healthcare System, Seattle, Washington, USA
| | - Jeffrey H Maki
- Radiology, University of Washington, Seattle, Washington, USA
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Lasič S, Oredsson S, Partridge SC, Saal LH, Topgaard D, Nilsson M, Bryskhe K. Apparent exchange rate for breast cancer characterization. NMR Biomed 2016; 29:631-9. [PMID: 26929050 PMCID: PMC4833667 DOI: 10.1002/nbm.3504] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 01/27/2016] [Accepted: 01/27/2016] [Indexed: 05/05/2023]
Abstract
Although diffusion MRI has shown promise for the characterization of breast cancer, it has low specificity to malignant subtypes. Higher specificity might be achieved if the effects of cell morphology and molecular exchange across cell membranes could be disentangled. The quantification of exchange might thus allow the differentiation of different types of breast cancer cells. Based on differences in diffusion rates between the intra- and extracellular compartments, filter exchange spectroscopy/imaging (FEXSY/FEXI) provides non-invasive quantification of the apparent exchange rate (AXR) of water between the two compartments. To test the feasibility of FEXSY for the differentiation of different breast cancer cells, we performed experiments on several breast epithelial cell lines in vitro. Furthermore, we performed the first in vivo FEXI measurement of water exchange in human breast. In cell suspensions, pulsed gradient spin-echo experiments with large b values and variable pulse duration allow the characterization of the intracellular compartment, whereas FEXSY provides a quantification of AXR. These experiments are very sensitive to the physiological state of cells and can be used to establish reliable protocols for the culture and harvesting of cells. Our results suggest that different breast cancer subtypes can be distinguished on the basis of their AXR values in cell suspensions. Time-resolved measurements allow the monitoring of the physiological state of cells in suspensions over the time-scale of hours, and reveal an abrupt disintegration of the intracellular compartment. In vivo, exchange can be detected in a tumor, whereas, in normal tissue, the exchange rate is outside the range experimentally accessible for FEXI. At present, low signal-to-noise ratio and limited scan time allows the quantification of AXR only in a region of interest of relatively large tumors.
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Affiliation(s)
| | | | - Savannah C Partridge
- Department of Radiology, University of Washington, Seattle Cancer Care Alliance, Seattle, Western Australia, USA
| | - Lao H Saal
- Division of Oncology and Pathology, Department of Clinical Sciences, Lund University Cancer Center, Lund, Sweden
| | - Daniel Topgaard
- Center for Chemistry and Chemical Engineering, Lund University
| | - Markus Nilsson
- Lund University Bioimaging Center, Lund University, Lund, Sweden
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Asai S, Fujimoto N, Tanoue K, Akamine E, Nakao E, Hashimoto K, Ichinona T, Nambara M, Sassa S, Yanagi H, Hirooka N, Mori T, Ogawa M, Ogawa A. Water immersion colonoscopy facilitates straight passage of the colonoscope through the sigmoid colon without loop formation: randomized controlled trial. Dig Endosc 2015; 27:345-53. [PMID: 25413483 DOI: 10.1111/den.12406] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 11/17/2014] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIM One of the major causes of pain during colonoscopy is looping of the instrument during insertion through the sigmoid colon, which causes discomfort by stretching the mesentery. There are many studies in colonoscope techniques, but they have not been assessed objectively with respect to colonoscope passage through the sigmoid colon without loop formation. The aim of the present study was to determine whether cap-fitted colonoscopy and water immersion increase the success rate of insertion through the sigmoid without loop formation. METHODS A total of 1005 patients were randomized to standard colonoscopy, cap-fitted colonoscopy or water immersion technique. All examinations were carried out under a magnetic endoscope imaging device. Main outcome was the success rate of insertion without loop formation. RESULTS Success rate of insertion without loop formation was 37.5%, 40.0%, and 53.8% in the standard, cap, and water groups, respectively (standard vs water P = 0.00014, cap vs water P = 0.00186). There were no significant differences among the groups regarding cecal intubation rate, cecal intubation time and number of polyps ≥5 mm per patient. CONCLUSIONS Water immersion increases the success rate of insertion through the sigmoid colon without loop formation. This practical technique, requiring only preparation of a cap and water, is useful without compromising cecal intubation rate, cecal intubation time, or polyp detection rate.
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Affiliation(s)
- Satoshi Asai
- Department of Gastroenterology, Tane General Hospital, Osaka, Japan
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Abstract
PURPOSE The aim of this study was to assess the uncertainty in estimation of MR tracer kinetic parameters and water exchange rates in T1-weighted dynamic contrast enhanced (DCE) MRI. METHODS Simulated DCE-MRI data were used to assess four kinetic models; general kinetic model with a vascular compartment (GKM2), GKM2 combined with water exchange (SSM2), adiabatic approximation of the tissue homogeneity model (ATH), and ATH combined with water exchange (ATHX). RESULTS In GKM2 and SSM2, increase in transfer constant (K(trans)) led to underestimation of vascular volume fraction (vb), and increase in vb led to overestimation of K(trans). Such coupling between K(trans) and vb was not observed in ATH and ATHX. The precision of estimated intracellular water lifetime (τi) was substantially improved in both SSM2 and ATHX when K(trans) > 0.3 min(-1). K(trans) and vb from ATHX model had significantly smaller errors than those from ATH model (P < 0.05). CONCLUSION The results of this study demonstrated the feasibility of measuring τi from DCE-MRI data albeit low precision. While the inclusion of water exchange improved the accuracy of K(trans), vb, and the interstitial volume fraction estimation (ve), it lowered the precision of other kinetic model parameters within the conditions investigated in this study.
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Affiliation(s)
- Jin Zhang
- Center for Biomedical Imaging, Department of Radiology, New York University, School of Medicine, New York, USA
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46
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van den Boer C, Vas Nunes JH, Muller SH, van der Noort V, van den Brekel MWM, Hilgers FJM. Water Uptake Performance of Hygroscopic Heat and Moisture Exchangers after 24-Hour Tracheostoma Application. Otolaryngol Head Neck Surg 2014; 150:999-1004. [PMID: 24682715 DOI: 10.1177/0194599814527420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 02/19/2014] [Indexed: 11/16/2022]
Abstract
OBJECTIVE After total laryngectomy, patients suffer from pulmonary complaints due to the shortcut of the upper airways that results in decreased warming and humidification of inspired air. Laryngectomized patients are advised to use a heat and moisture exchanger (HME) to optimize the inspired air. According to manufacturers' guidelines, these medical devices should be replaced every 24 hours. The aim of this study is to determine whether HMEs still function after 24-hour tracheostoma application. STUDY DESIGN Assessment of residual water uptake capacity of used HMEs by measuring the difference between wet and dry core weight. SETTING Tertiary comprehensive cancer center. SUBJECTS AND METHODS Three hygroscopic HME types were tested after use by laryngectomized patients in long-term follow-up. Water uptake of 41 used devices (including 10 prematurely replaced devices) was compared with that of control (unused) devices of the same type and with a control device with a relatively low performance. RESULTS After 24 hours, the mean water uptake of the 3 device types had decreased compared with that of the control devices. For only one type was this difference significant. None of the used HMEs had a water uptake lower than that of the low-performing control device. CONCLUSION The water uptake capacity of hygroscopic HEMs is clinically acceptable although no longer optimal after 24-hour tracheostoma application. From a functional point of view, the guideline for daily device replacement is therefore justified.
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Affiliation(s)
- Cindy van den Boer
- Department of Head and Neck Oncology and Surgery, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Amsterdam, The Netherlands
| | - Jonathan H Vas Nunes
- Department of Head and Neck Oncology and Surgery, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Amsterdam, The Netherlands
| | - Sara H Muller
- Department of Clinical Physics and Instrumentation, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Amsterdam, The Netherlands
| | - Vincent van der Noort
- Department of Biometrics, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Amsterdam, The Netherlands
| | - Michiel W M van den Brekel
- Department of Head and Neck Oncology and Surgery, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Amsterdam, The Netherlands Institute of Phonetic Sciences (ACLC), University of Amsterdam, The Netherlands Department of Oral-Maxillofacial Surgery, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Frans J M Hilgers
- Department of Head and Neck Oncology and Surgery, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Amsterdam, The Netherlands Institute of Phonetic Sciences (ACLC), University of Amsterdam, The Netherlands
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47
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Zhang J, Kim S. Uncertainty in MR tracer kinetic parameters and water exchange rates estimated from T1-weighted dynamic contrast enhanced MRI. Magn Reson Med 2013; 72:534-45. [PMID: 24006341 DOI: 10.1002/mrm.24927] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 07/24/2013] [Accepted: 07/29/2013] [Indexed: 01/02/2023]
Abstract
PURPOSE The aim of this study was to assess the uncertainty in estimation of MR tracer kinetic parameters and water exchange rates in T1-weighted dynamic contrast enhanced (DCE) MRI. METHODS Simulated DCE-MRI data were used to assess four kinetic models; general kinetic model with a vascular compartment (GKM2), GKM2 combined with water exchange (SSM2), adiabatic approximation of the tissue homogeneity model (ATH), and ATH combined with water exchange (ATHX). RESULTS In GKM2 and SSM2, increase in transfer constant (K(trans)) led to underestimation of vascular volume fraction (vb), and increase in vb led to overestimation of K(trans). Such coupling between K(trans) and vb was not observed in ATH and ATHX. The precision of estimated intracellular water lifetime (τi) was substantially improved in both SSM2 and ATHX when K(trans) > 0.3 min(-1). K(trans) and vb from ATHX model had significantly smaller errors than those from ATH model (P < 0.05). CONCLUSION The results of this study demonstrated the feasibility of measuring τi from DCE-MRI data albeit low precision. While the inclusion of water exchange improved the accuracy of K(trans), vb, and the interstitial volume fraction estimation (ve), it lowered the precision of other kinetic model parameters within the conditions investigated in this study.
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Affiliation(s)
- Jin Zhang
- Center for Biomedical Imaging, Department of Radiology, New York University, School of Medicine, New York, USA
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Huang S, Kim JK, Atochin DN, Farrar CT, Huang PL, Suh JY, Kwon SJ, Shim WH, Cho H, Cho G, Kim YR. Cerebral blood volume affects blood-brain barrier integrity in an acute transient stroke model. J Cereb Blood Flow Metab 2013; 33:898-905. [PMID: 23462571 DOI: 10.1038/jcbfm.2013.27] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Insufficient vascular reserve after an ischemic stroke may induce biochemical cascades that subsequently deteriorate the blood-brain barrier (BBB) function. However, the direct relationship between poor cerebral blood volume (CBV) restoration and BBB disruption has not been examined in acute stroke. To quantify BBB integrity at acute stages of transient stroke, in particular for cases in which extravasation of the standard contrast agent (Gd-DTPA) is not observed, we adopted the water exchange index (WEI), a novel magnetic resonance image-derived parameter to estimate the water permeability across the BBB. The apparent diffusion coefficient (ADC) and R2 relaxation rate constant were also measured for outlining the tissue abnormality, while fractional CBV and WEI were quantified for assessing vascular alterations. The significantly decreased ADC and R2 in the ischemic cortices did not correlate with the changes in CBV or WEI. In contrast, a strong negative correlation between the ipsilesional WEI and CBV was found, in which stroke mice were clustered into two groups: (1) high WEI and low CBV and (2) normal WEI and CBV. The low CBV observed for mice with a disrupted BBB, characterized by a high WEI, indicates the importance of CBV restoration for maintaining BBB stability in acute stroke.
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Huang S, Farrar CT, Dai G, Kwon SJ, Bogdanov AA, Rosen BR, Kim YR. Dynamic monitoring of blood-brain barrier integrity using water exchange index (WEI) during mannitol and CO2 challenges in mouse brain. NMR Biomed 2013; 26:376-85. [PMID: 23055278 PMCID: PMC4029920 DOI: 10.1002/nbm.2871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2012] [Revised: 07/16/2012] [Accepted: 08/27/2012] [Indexed: 05/13/2023]
Abstract
The integrity of the blood-brain barrier (BBB) is critical to normal brain function. Traditional techniques for the assessment of BBB disruption rely heavily on the spatiotemporal analysis of extravasating contrast agents. However, such methods based on the leakage of relatively large molecules are not suitable for the detection of subtle BBB impairment or for the performance of repeated measurements in a short time frame. Quantification of the water exchange rate constant (WER) across the BBB using strictly intravascular contrast agents could provide a much more sensitive method for the quantification of the BBB integrity. To estimate WER, we have recently devised a powerful new method using a water exchange index (WEI) biomarker and demonstrated BBB disruption in an acute stroke model. Here, we confirm that WEI is sensitive to even very subtle changes in the integrity of the BBB caused by: (i) systemic hypercapnia and (ii) low doses of a hyperosmolar solution. In addition, we have examined the sensitivity and accuracy of WEI as a biomarker of WER using computer simulation. In particular, the dependence of the WEI-WER relation on changes in vascular blood volume, T1 relaxation of cellular magnetization and transcytolemmal water exchange was explored. Simulated WEI was found to vary linearly with WER for typically encountered exchange rate constants (1-4 Hz), regardless of the blood volume. However, for very high WER (>5 Hz), WEI became progressively more insensitive to increasing WER. The incorporation of transcytolemmal water exchange, using a three-compartment tissue model, helped to extend the linear WEI regime to slightly higher WER, but had no significant effect for most physiologically important WERs (WER < 4 Hz). Variation in cellular T1 had no effect on WEI. Using both theoretical and experimental approaches, our study validates the utility of the WEI biomarker for the monitoring of BBB integrity.
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Affiliation(s)
- Shuning Huang
- Health Science and Technology (HST), Massachusetts Institute of Technology, Cambridge, MA 02139
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129
| | - Christian T. Farrar
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129
| | - Guangping Dai
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129
| | - Seon Joo Kwon
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129
| | | | - Bruce R. Rosen
- Health Science and Technology (HST), Massachusetts Institute of Technology, Cambridge, MA 02139
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129
| | - Young R. Kim
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129
- Corresponding author: Young Ro Kim Assistant Professor, Harvard Medical School Harvard-MIT (HST) Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital-East Bldg. 149, 13th Street Charlestown, MA 02129 Fax: 617-726-7422
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50
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Polasek M, Caravan P. Is macrocycle a synonym for kinetic inertness in Gd(III) Complexes? Effect of coordinating and noncoordinating substituents on inertness and relaxivity of Gd(III) chelates with DO3A-like ligands. Inorg Chem 2013; 52:4084-96. [PMID: 23517079 PMCID: PMC3640422 DOI: 10.1021/ic400227k] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gadolinium chelates with octadentate ligands are widely used as contrast agents for magnetic resonance imaging (MRI), with macrocyclic ligands based on DO3A being preferred for the high kinetic inertness of their Gd chelates. A major challenge in the design of new bifunctional MRI probes is the need to control the rotational motion of the chelate, which greatly affects its relaxivity. In this work we explored facile alkylation of a secondary amine in macrocyclic DO3A-like ligands to create a short, achiral linkage to limit the undesired internal motion of chelates within larger molecular constructs. The acetate moiety on the trans nitrogen was also replaced with either a bidentate (ethoxyacetate, L1 or methyl picolinate, L2) or bulky monodentate (methyl phosphonate, L3) donor arm to give octa- or heptadentate ligands, respectively. The resultant Gd(III) complexes were all monohydrated (q = 1) and exhibited water residency times that spanned 2 orders of magnitude (τM = 2190 ± 170, 3500 ± 90, and 12.7 ± 3.8 ns at 37 °C for GdL1, GdL2, and GdL3, respectively). Alkylation of the secondary amine with a noncoordinating biphenyl moiety resulted in coordinatively saturated q = 0 complexes of octadentate ligands L1 and L2. Relaxivities were limited by slow water exchange and/or lack of water coligand. All complexes showed decreased inertness compared to [Gd(DO3A)] despite higher ligand denticity, and inertness was further decreased upon N-alkylation. These results demonstrate that high kinetic inertness and in vivo safety of Gd chelates with macrocyclic ligands should not be generalized.
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Affiliation(s)
- Miloslav Polasek
- The Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, MA 02129
| | - Peter Caravan
- The Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, MA 02129
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