1
|
Triana Y, Ogata G, Tomisaki M, Irkham, Einaga Y. Blood Oxygen Sensor Using a Boron-Doped Diamond Electrode. Anal Chem 2022; 94:3948-3955. [PMID: 35192326 DOI: 10.1021/acs.analchem.1c04999] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The electrochemical behavior of oxygen (O2) in blood was studied using boron-doped diamond (BDD) electrodes. Cyclic voltammogram of O2 in a 0.1 M phosphate buffer solution solution containing 1 × 10-6 M of bovine hemoglobin exhibits a reduction peak at -1.4 V (vs Ag/AgCl). Moreover, the scan rate dependence was investigated to study the reduction reaction mechanism, which was attributable to the reduction of O2 to H2O2 via two electrons. A linear calibration curve was observed in the concentration range of 86.88-314.63 mg L-1 (R2 = 0.99) with a detection limit of 1.0 mg L-1 (S/B = 3). The analytical performance was better than those with glassy carbon or platinum electrodes as the working electrode. In addition, an application to bovine blood was performed. The O2 concentration in the blood measured on the BDD electrodes was compared to that measured using an OxyLite Pro fiber-optic oxygen sensor device. Both methods gave similar values of the O2 concentration in the range of ∼40 to 150 mmHg. This result confirms that BDD electrodes could potentially be used to detect the O2 concentration in blood.
Collapse
Affiliation(s)
- Yunita Triana
- Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Yokohama 2238522, Japan.,Department of Materials and Metallurgical Engineering, Institut Teknologi Kalimantan, Balikpapan 76127, Indonesia
| | - Genki Ogata
- Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Yokohama 2238522, Japan
| | - Mai Tomisaki
- Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Yokohama 2238522, Japan
| | - Irkham
- Department of Chemistry, Universitas Padjadjaran, Sumedang 45363, Indonesia
| | - Yasuaki Einaga
- Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Yokohama 2238522, Japan
| |
Collapse
|
2
|
Shih CM, Lo HC, Hsieh MC, Chen JH. Functional quantitative susceptibility mapping (fQSM) of rat brain during flashing light stimulation. Neuroimage 2021; 233:117924. [PMID: 33753240 DOI: 10.1016/j.neuroimage.2021.117924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 10/21/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) based on the blood oxygenation level-dependent (BOLD) contrast has become an indispensable tool in neuroscience. However, the BOLD signal is nonlocal, lacking quantitative measurement of oxygenation fluctuation. This preclinical study aimed to introduced functional quantitative susceptibility mapping (fQSM) to complement BOLD-fMRI to quantitatively assess the local susceptibility and venous oxygen saturation (SvO2). Rats were subjected to a 5 Hz flashing light and the different inhaled oxygenation levels (30% and 100%) were used to observe the venous susceptibility to quantify SvO2. Phase information was extracted to produce QSM, and the activation responses of magnitude (conventional BOLD) and the QSM time-series were analyzed. During light stimulation, the susceptibility change of fQSM was four times larger than the BOLD signal change in both inhalation oxygenation conditions. Moreover, the responses in the fQSM map were more restricted to the visual pathway, such as the lateral geniculate nucleus and superior colliculus, compared with the relatively diffuse distributions in the BOLD map. Also, the calibrated SvO2 was approximately 84% (88%) when the task was on, 83% (87%) when the task was off during 30% (and during 100%) oxygen inhalation. This is the first fQSM study in a small animal model and increases our understanding of fQSM in the brains of small animals. This study demonstrated the feasibility, sensitivity, and specificity of fQSM using light stimulus, as fQSM provides quantitative clues as well as localized information, complementing the defects of BOLD-fMRI. In addition to neural activity, fQSM also assesses SvO2 as supplementary information while BOLD-fMRI dose not. Accordingly, the fQSM technique could be a useful quantitative tool for functional studies, such as longitudinal follow up of neurodegenerative diseases, functional recovery after brain surgery, and negative BOLD studies.
Collapse
Affiliation(s)
- Chia-Ming Shih
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 106, Taiwan; Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University, Taipei 106, Taiwan; Molecular Imaging Center, National Taiwan University, Taipei 106, Taiwan
| | - Hsin-Chih Lo
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 106, Taiwan; Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University, Taipei 106, Taiwan; Molecular Imaging Center, National Taiwan University, Taipei 106, Taiwan
| | - Meng-Chi Hsieh
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 106, Taiwan; Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University, Taipei 106, Taiwan; Molecular Imaging Center, National Taiwan University, Taipei 106, Taiwan
| | - Jyh-Horng Chen
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 106, Taiwan; Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University, Taipei 106, Taiwan; Molecular Imaging Center, National Taiwan University, Taipei 106, Taiwan.
| |
Collapse
|
3
|
Yang DM, Arai TJ, Campbell JW, Gerberich JL, Zhou H, Mason RP. Oxygen-sensitive MRI assessment of tumor response to hypoxic gas breathing challenge. NMR IN BIOMEDICINE 2019; 32:e4101. [PMID: 31062902 PMCID: PMC6581571 DOI: 10.1002/nbm.4101] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 02/16/2019] [Accepted: 03/08/2019] [Indexed: 06/09/2023]
Abstract
Oxygen-sensitive MRI has been extensively used to investigate tumor oxygenation based on the response (R2 * and/or R1 ) to a gas breathing challenge. Most studies have reported response to hyperoxic gas indicating potential biomarkers of hypoxia. Few studies have examined hypoxic gas breathing and we have now evaluated acute dynamic changes in rat breast tumors. Rats bearing syngeneic subcutaneous (n = 15) or orthotopic (n = 7) 13762NF breast tumors were exposed to a 16% O2 gas breathing challenge and monitored using blood oxygen level dependent (BOLD) R2 * and tissue oxygen level dependent (TOLD) T1 -weighted measurements at 4.7 T. As a control, we used a traditional hyperoxic gas breathing challenge with 100% O2 on a subset of the subcutaneous tumor bearing rats (n = 6). Tumor subregions identified as responsive on the basis of R2 * dynamics coincided with the viable tumor area as judged by subsequent H&E staining. As expected, R2 * decreased and T1 -weighted signal increased in response to 100% O2 breathing challenge. Meanwhile, 16% O2 breathing elicited an increase in R2 *, but divergent response (increase or decrease) in T1 -weighted signal. The T1 -weighted signal increase may signify a dominating BOLD effect triggered by 16% O2 in the relatively more hypoxic tumors, whereby the influence of increased paramagnetic deoxyhemoglobin outweighs decreased pO2 . The results emphasize the importance of combined BOLD and TOLD measurements for the correct interpretation of tumor oxygenation properties.
Collapse
Affiliation(s)
- Donghan M Yang
- Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Tatsuya J Arai
- Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - James W Campbell
- Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, USA
| | | | - Heling Zhou
- Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Ralph P Mason
- Department of Radiology, UT Southwestern Medical Center, Dallas, Texas, USA
| |
Collapse
|
4
|
Niazi M, Karaman M, Das S, Zhou XJ, Yushkevich P, Cai K. Quantitative MRI of Perivascular Spaces at 3T for Early Diagnosis of Mild Cognitive Impairment. AJNR Am J Neuroradiol 2018; 39:1622-1628. [PMID: 30093484 DOI: 10.3174/ajnr.a5734] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 06/02/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The limitations inherent in the current methods of diagnosing mild cognitive impairment have constrained the use of early therapeutic interventions to delay the progression of mild cognitive impairment to dementia. This study evaluated whether quantifying enlarged perivascular spaces observed on MR imaging can help differentiate those with mild cognitive impairment from cognitively healthy controls and, thus, have an application in the diagnosis of mild cognitive impairment. MATERIALS AND METHODS We automated the identification of enlarged perivascular spaces in brain MR Images using a custom quantitative program designed with Matlab. We then quantified the densities of enlarged perivascular spaces for patients with mild cognitive impairment (n = 14) and age-matched cognitively healthy controls (n = 15) and compared them to determine whether the density of enlarged perivascular spaces can serve as an imaging surrogate for mild cognitive impairment diagnosis. RESULTS Quantified as a percentage of volume fraction (v/v%), densities of enlarged perivascular spaces were calculated to be 2.82 ± 0.40 v/v% for controls and 4.17 ± 0.57 v/v% for the mild cognitive impairment group in the subcortical brain (P < .001), and 2.74 ± 0.57 v/v% for the controls and 3.90 ± 0.62 v/v% for the mild cognitive impairment cohort in the basal ganglia (P < .001). Maximum intensity projections exhibited a visually conspicuous difference in the distributions of enlarged perivascular spaces for a patient with mild cognitive impairment and a control patient. By means of receiver operating characteristic curve analysis, we determined the sensitivity and specificity of using enlarged perivascular spaces as a differentiating biomarker between mild cognitive impairment and controls to be 92.86% and 93.33%, respectively. CONCLUSIONS The density of enlarged perivascular spaces was found to be significantly higher in those with mild cognitive impairment compared with age-matched healthy control subjects. The density of enlarged perivascular spaces, therefore, may be a useful imaging biomarker for the diagnosis of mild cognitive impairment.
Collapse
Affiliation(s)
- M Niazi
- From the Department of Radiology (M.N., X.J.Z., K.C.).,Chicago College of Osteopathic Medicine (M.N.), Midwestern University, Downers Grove, Illinois
| | - M Karaman
- Center for MR Research (M.K., X.J.Z., K.C.), College of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - S Das
- Department of Radiology (S.D., P.Y.), School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - X J Zhou
- From the Department of Radiology (M.N., X.J.Z., K.C.).,Center for MR Research (M.K., X.J.Z., K.C.), College of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - P Yushkevich
- Department of Radiology (S.D., P.Y.), School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - K Cai
- From the Department of Radiology (M.N., X.J.Z., K.C.) .,Center for MR Research (M.K., X.J.Z., K.C.), College of Medicine, University of Illinois at Chicago, Chicago, Illinois
| |
Collapse
|
5
|
Hsieh M, Kuo L, Huang Y, Chen J. Investigating hyperoxic effects in the rat brain using quantitative susceptibility mapping based on MRI phase. Magn Reson Med 2016; 77:592-602. [DOI: 10.1002/mrm.26139] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 12/25/2015] [Accepted: 01/05/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Meng‐Chi Hsieh
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan UniversityTaipei 106 Taiwan
- Molecular Imaging Center, National Taiwan UniversityTaipei 106 Taiwan
- Department of Electrical EngineeringNational Taiwan UniversityTaipei 106 Taiwan
| | - Li‐Wei Kuo
- Institute of Biomedical Engineering and Nanomedicine, National Health Research InstitutesMiaoli County 350 Taiwan
| | - Yun‐An Huang
- Department of Electrical EngineeringNational Taiwan UniversityTaipei 106 Taiwan
| | - Jyh‐Horng Chen
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan UniversityTaipei 106 Taiwan
- Molecular Imaging Center, National Taiwan UniversityTaipei 106 Taiwan
- Department of Electrical EngineeringNational Taiwan UniversityTaipei 106 Taiwan
| |
Collapse
|
6
|
Cai K, Tain R, Das S, Damen FC, Sui Y, Valyi-Nagy T, Elliott MA, Zhou XJ. The feasibility of quantitative MRI of perivascular spaces at 7T. J Neurosci Methods 2015; 256:151-6. [PMID: 26358620 DOI: 10.1016/j.jneumeth.2015.09.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 08/05/2015] [Accepted: 09/01/2015] [Indexed: 01/05/2023]
Abstract
BACKGROUND Dilated brain perivascular spaces (PVSs) are found to be associated with many conditions, including aging, dementia, and Alzheimer's disease (AD). Conventionally, PVS assessment is mainly based on subjective observations of the number, size and shape of PVSs in MR images collected at clinical field strengths (≤3T). This study tests the feasibility of imaging and quantifying brain PVS with an ultra-high 7T whole-body MRI scanner. NEW METHOD 3D high resolution T2-weighted brain images from healthy subjects (n=3) and AD patients (n=5) were acquired on a 7T whole-body MRI scanner. To automatically segment the small hyperintensive fluid-filling PVS structures, we also developed a quantitative program based on algorithms for spatial gradient, component connectivity, edge-detection, k-means clustering, etc., producing quantitative results of white matter PVS volume densities. RESULTS The 3D maps of automatically segmented PVS show an apparent increase in PVS density in AD patients compared to age-matched healthy controls due to the PVS dilation (8.0±2.1 v/v% in AD vs. 4.9±1.3 v/v% in controls, p<0.05). COMPARISON WITH EXISTING METHOD We demonstrated that 7T provides sufficient SNR and resolution for quantitatively measuring PVSs in deep white matter that is challenging with clinical MRI systems (≤3T). Compared to the conventional visual counting and rating for the PVS assessment, the quantitation method we developed is automatic and objective. CONCLUSIONS Quantitative PVS MRI at 7T may serve as a non-invasive and endogenous imaging biomarker for diseases with PVS dilation.
Collapse
Affiliation(s)
- Kejia Cai
- Department of Radiology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA; Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
| | - Rongwen Tain
- Department of Radiology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA; Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Sandhitsu Das
- Department of Radiology, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Frederick C Damen
- Department of Radiology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA; Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Yi Sui
- Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA; Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Tibor Valyi-Nagy
- Department of Neuropathology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Mark A Elliott
- Department of Radiology, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Xiaohong J Zhou
- Department of Radiology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA; Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| |
Collapse
|
7
|
Cai K, Xu HN, Singh A, Moon L, Haris M, Reddy R, Li LZ. Breast cancer redox heterogeneity detectable with chemical exchange saturation transfer (CEST) MRI. Mol Imaging Biol 2015; 16:670-9. [PMID: 24811957 DOI: 10.1007/s11307-014-0739-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
PURPOSE Tissue redox state is an important mediator of various biological processes in health and diseases such as cancer. Previously, we discovered that the mitochondrial redox state of ex vivo tissues detected by redox scanning (an optical imaging method) revealed interesting tumor redox state heterogeneity that could differentiate tumor aggressiveness. Because the noninvasive chemical exchange saturation transfer (CEST) MRI can probe the proton transfer and generate contrasts from endogenous metabolites, we aim to investigate if the in vivo CEST contrast is sensitive to proton transfer of the redox reactions so as to reveal the tissue redox states in breast cancer animal models. PROCEDURES CEST MRI has been employed to characterize tumor metabolic heterogeneity and correlated with the redox states measured by the redox scanning in two human breast cancer mouse xenograft models, MDA-MB-231 and MCF-7. The possible biological mechanism on the correlation between the two imaging modalities was further investigated by phantom studies where the reductants and the oxidants of the representative redox reactions were measured. RESULTS The CEST contrast is found linearly correlated with NADH concentration and the NADH redox ratio with high statistical significance, where NADH is the reduced form of nicotinamide adenine dinucleotide. The phantom studies showed that the reductants of the redox reactions have more CEST contrast than the corresponding oxidants, indicating that higher CEST effect corresponds to the more reduced redox state. CONCLUSIONS This preliminary study suggests that CEST MRI, once calibrated, might provide a novel noninvasive imaging surrogate for the tissue redox state and a possible diagnostic biomarker for breast cancer in the clinic.
Collapse
Affiliation(s)
- Kejia Cai
- Department of Radiology, University of Illinois College of Medicine, Chicago, IL, USA,
| | | | | | | | | | | | | |
Collapse
|
8
|
Abstract
In view of the trend towards personalized treatment strategies for (cancer) patients, there is an increasing need to noninvasively determine individual patient characteristics. Such information enables physicians to administer to patients accurate therapy with appropriate timing. For the noninvasive visualization of disease-related features, imaging biomarkers are expected to play a crucial role. Next to the chemical development of imaging probes, this requires preclinical studies in animal tumour models. These studies provide proof-of-concept of imaging biomarkers and help determine the pharmacokinetics and target specificity of relevant imaging probes, features that provide the fundamentals for translation to the clinic. In this review we describe biological processes derived from the “hallmarks of cancer” that may serve as imaging biomarkers for diagnostic, prognostic and treatment response monitoring that are currently being studied in the preclinical setting. A number of these biomarkers are also being used for the initial preclinical assessment of new intervention strategies. Uniquely, noninvasive imaging approaches allow longitudinal assessment of changes in biological processes, providing information on the safety, pharmacokinetic profiles and target specificity of new drugs, and on the antitumour effectiveness of therapeutic interventions. Preclinical biomarker imaging can help guide translation to optimize clinical biomarker imaging and personalize (combination) therapies.
Collapse
|
9
|
Huang CH, Chen CCV, Siow TY, Hsu SHS, Hsu YH, Jaw FS, Chang C. High-resolution structural and functional assessments of cerebral microvasculature using 3D Gas ΔR2*-mMRA. PLoS One 2013; 8:e78186. [PMID: 24223773 PMCID: PMC3817180 DOI: 10.1371/journal.pone.0078186] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Accepted: 09/09/2013] [Indexed: 11/19/2022] Open
Abstract
The ability to evaluate the cerebral microvascular structure and function is crucial for investigating pathological processes in brain disorders. Previous angiographic methods based on blood oxygen level-dependent (BOLD) contrast offer appropriate visualization of the cerebral vasculature, but these methods remain to be optimized in order to extract more comprehensive information. This study aimed to integrate the advantages of BOLD MRI in both structural and functional vascular assessments. The BOLD contrast was manipulated by a carbogen challenge, and signal changes in gradient-echo images were computed to generate ΔR2* maps. Simultaneously, a functional index representing the regional cerebral blood volume was derived by normalizing the ΔR2* values of a given region to those of vein-filled voxels of the sinus. This method is named 3D gas ΔR2*-mMRA (microscopic MRA). The advantages of using 3D gas ΔR2*-mMRA to observe the microvasculature include the ability to distinguish air-tissue interfaces, a high vessel-to-tissue contrast, and not being affected by damage to the blood-brain barrier. A stroke model was used to demonstrate the ability of 3D gas ΔR2*-mMRA to provide information about poststroke revascularization at 3 days after reperfusion. However, this technique has some limitations that cannot be overcome and hence should be considered when it is applied, such as magnifying vessel sizes and predominantly revealing venous vessels.
Collapse
Affiliation(s)
- Chien-Hsiang Huang
- Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
- Institute of Biomedical Sciences, Academic Sinica, Taipei, Taiwan
| | | | - Tiing-Yee Siow
- Institute of Biomedical Sciences, Academic Sinica, Taipei, Taiwan
| | | | - Yi-Hua Hsu
- Institute of Biomedical Sciences, Academic Sinica, Taipei, Taiwan
| | - Fu-Shan Jaw
- Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
| | - Chen Chang
- Institute of Biomedical Sciences, Academic Sinica, Taipei, Taiwan
| |
Collapse
|
10
|
Ehling J, Lammers T, Kiessling F. Non-invasive imaging for studying anti-angiogenic therapy effects. Thromb Haemost 2013; 109:375-90. [PMID: 23407722 DOI: 10.1160/th12-10-0721] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 12/28/2012] [Indexed: 12/14/2022]
Abstract
Noninvasive imaging plays an emerging role in preclinical and clinical cancer research and has high potential to improve clinical translation of new drugs. This article summarises and discusses tools and methods to image tumour angiogenesis and monitor anti-angiogenic therapy effects. In this context, micro-computed tomography (µCT) is recommended to visualise and quantify the micro-architecture of functional tumour vessels. Contrast-enhanced ultrasound (US) and magnetic resonance imaging (MRI) are favourable tools to assess functional vascular parameters, such as perfusion and relative blood volume. These functional parameters have been shown to indicate anti-angiogenic therapy response at an early stage, before changes in tumour size appear. For tumour characterisation, the imaging of the molecular characteristics of tumour blood vessels, such as receptor expression, might have an even higher diagnostic potential and has been shown to be highly suitable for therapy monitoring as well. In this context, US using targeted microbubbles is currently evaluated in clinical trials as an important tool for the molecular characterisation of the angiogenic endothelium. Other modalities, being preferably used for molecular imaging of vessels and their surrounding stroma, are photoacoustic imaging (PAI), near-infrared fluorescence optical imaging (OI), MRI, positron emission tomography (PET) and single photon emission computed tomography (SPECT). The latter two are particularly useful if very high sensitivity is needed, and/or if the molecular target is difficult to access. Carefully considering the pros and cons of different imaging modalities in a multimodal imaging setup enables a comprehensive longitudinal assessment of the (micro)morphology, function and molecular regulation of tumour vessels.
Collapse
Affiliation(s)
- Josef Ehling
- Department of Experimental Molecular Imaging, Medical Faculty and Helmholtz Institute for Biomedical Engineering, Pauwelsstraße 30, 52074 Aachen, Germany
| | | | | |
Collapse
|