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He Z, Lefebvre PM, Soullié P, Doguet M, Ambarki K, Chen B, Odille F. Phantom evaluation of electrical conductivity mapping by MRI: Comparison to vector network analyzer measurements and spatial resolution assessment. Magn Reson Med 2024; 91:2374-2390. [PMID: 38225861 DOI: 10.1002/mrm.30009] [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: 11/10/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 01/17/2024]
Abstract
PURPOSE To evaluate the performance of various MR electrical properties tomography (MR-EPT) methods at 3 T in terms of absolute quantification and spatial resolution limit for electrical conductivity. METHODS Absolute quantification as well as spatial resolution performance were evaluated on homogeneous phantoms and a phantom with holes of different sizes, respectively. Ground-truth conductivities were measured with an open-ended coaxial probe connected to a vector network analyzer (VNA). Four widely used MR-EPT reconstruction methods were investigated: phase-based Helmholtz (PB), phase-based convection-reaction (PB-cr), image-based (IB), and generalized-image-based (GIB). These methods were compared using the same complex images from a 1 mm-isotropic UTE sequence. Alternative transceive phase acquisition sequences were also compared in PB and PB-cr. RESULTS In large homogeneous phantoms, all methods showed a strong correlation with ground truth conductivities (r > 0.99); however, GIB was the best in terms of accuracy, spatial uniformity, and robustness to boundary artifacts. In the resolution phantom, the normalized root-mean-squared error of all methods grew rapidly (>0.40) when the hole size was below 10 mm, with simplified methods (PB and IB), or below 5 mm, with generalized methods (PB-cr and GIB). CONCLUSION VNA measurements are essential to assess the accuracy of MR-EPT. In this study, all tested MR-EPT methods correlated strongly with the VNA measurements. The UTE sequence is recommended for MR-EPT, with the GIB method providing good accuracy for structures down to 5 mm. Structures below 5 mm may still be detected in the conductivity maps, but with significantly lower accuracy.
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Affiliation(s)
- Zhongzheng He
- IADI U1254, INSERM and Université de Lorraine, Nancy, France
| | | | - Paul Soullié
- IADI U1254, INSERM and Université de Lorraine, Nancy, France
| | - Martin Doguet
- IADI U1254, INSERM and Université de Lorraine, Nancy, France
- BioSerenity, Paris, France
| | | | - Bailiang Chen
- IADI U1254, INSERM and Université de Lorraine, Nancy, France
- CIC-IT 1433, INSERM, Université de Lorraine and CHRU Nancy, Nancy, France
| | - Freddy Odille
- IADI U1254, INSERM and Université de Lorraine, Nancy, France
- CIC-IT 1433, INSERM, Université de Lorraine and CHRU Nancy, Nancy, France
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Marin-Castrillon DM, Geronzi L, Boucher A, Lin S, Morgant MC, Cochet A, Rochette M, Leclerc S, Ambarki K, Jin N, Aho LS, Lalande A, Bouchot O, Presles B. Segmentation of the aorta in systolic phase from 4D flow MRI: multi-atlas vs. deep learning. MAGMA 2023; 36:687-700. [PMID: 36800143 DOI: 10.1007/s10334-023-01066-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 07/15/2022] [Revised: 11/26/2022] [Accepted: 01/24/2023] [Indexed: 02/18/2023]
Abstract
OBJECTIVE In the management of the aortic aneurysm, 4D flow magnetic resonance Imaging provides valuable information for the computation of new biomarkers using computational fluid dynamics (CFD). However, accurate segmentation of the aorta is required. Thus, our objective is to evaluate the performance of two automatic segmentation methods on the calculation of aortic wall pressure. METHODS Automatic segmentation of the aorta was performed with methods based on deep learning and multi-atlas using the systolic phase in the 4D flow MRI magnitude image of 36 patients. Using mesh morphing, isotopological meshes were generated, and CFD was performed to calculate the aortic wall pressure. Node-to-node comparisons of the pressure results were made to identify the most robust automatic method respect to the pressures obtained with a manually segmented model. RESULTS Deep learning approach presented the best segmentation performance with a mean Dice similarity coefficient and a mean Hausdorff distance (HD) equal to 0.92+/- 0.02 and 21.02+/- 24.20 mm, respectively. At the global level HD is affected by the performance in the abdominal aorta. Locally, this distance decreases to 9.41+/- 3.45 and 5.82+/- 6.23 for the ascending and descending thoracic aorta, respectively. Moreover, with respect to the pressures from the manual segmentations, the differences in the pressures computed from deep learning were lower than those computed from multi-atlas method. CONCLUSION To reduce biases in the calculation of aortic wall pressure, accurate segmentation is needed, particularly in regions with high blood flow velocities. Thus, the deep learning segmen-tation method should be preferred.
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Affiliation(s)
| | | | - Arnaud Boucher
- Imaging and Artificial Vision Research Laboratory, University of Burgundy, Dijon, France
| | - Siyu Lin
- Imaging and Artificial Vision Research Laboratory, University of Burgundy, Dijon, France
| | - Marie-Catherine Morgant
- Imaging and Artificial Vision Research Laboratory, University of Burgundy, Dijon, France
- Department of cardiovascular and thoracic surgery, University Hospital of Dijon, Dijon, France
| | - Alexandre Cochet
- Imaging and Artificial Vision Research Laboratory, University of Burgundy, Dijon, France
- Medical Imaging Department, University Hospital of Dijon, Dijon, France
| | | | - Sarah Leclerc
- Imaging and Artificial Vision Research Laboratory, University of Burgundy, Dijon, France
| | | | - Ning Jin
- Siemens Medical Solutions, Nancy, France
| | - Ludwig Serge Aho
- Department of Epidemiology and Hygiene, University Hospital of Dijon, Dijon, France
| | - Alain Lalande
- Imaging and Artificial Vision Research Laboratory, University of Burgundy, Dijon, France
- Medical Imaging Department, University Hospital of Dijon, Dijon, France
| | - Olivier Bouchot
- Imaging and Artificial Vision Research Laboratory, University of Burgundy, Dijon, France
- Department of cardiovascular and thoracic surgery, University Hospital of Dijon, Dijon, France
| | - Benoit Presles
- Imaging and Artificial Vision Research Laboratory, University of Burgundy, Dijon, France.
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Wary P, Hossu G, Ambarki K, Nickel D, Arberet S, Oster J, Orry X, Laurent V. Deep learning HASTE sequence compared with T2-weighted BLADE sequence for liver MRI at 3 Tesla: a qualitative and quantitative prospective study. Eur Radiol 2023; 33:6817-6827. [PMID: 37188883 DOI: 10.1007/s00330-023-09693-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 08/21/2022] [Revised: 02/26/2023] [Accepted: 03/11/2023] [Indexed: 05/17/2023]
Abstract
OBJECTIVES To qualitatively and quantitatively compare a single breath-hold fast half-Fourier single-shot turbo spin echo sequence with deep learning reconstruction (DL HASTE) with T2-weighted BLADE sequence for liver MRI at 3 T. METHODS From December 2020 to January 2021, patients with liver MRI were prospectively included. For qualitative analysis, sequence quality, presence of artifacts, conspicuity, and presumed nature of the smallest lesion were assessed using the chi-squared and McNemar tests. For quantitative analysis, number of liver lesions, size of the smallest lesion, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in both sequences were assessed using the paired Wilcoxon signed-rank test. Intraclass correlation coefficients (ICCs) and kappa coefficients were used to assess agreement between the two readers. RESULTS One hundred and twelve patients were evaluated. Overall image quality (p = .006), artifacts (p < .001), and conspicuity of the smallest lesion (p = .001) were significantly better for the DL HASTE sequence than for the T2-weighted BLADE sequence. Significantly more liver lesions were detected with the DL HASTE sequence (356 lesions) than with the T2-weighted BLADE sequence (320 lesions; p < .001). CNR was significantly higher for the DL HASTE sequence (p < .001). SNR was higher for the T2-weighted BLADE sequence (p < .001). Interreader agreement was moderate to excellent depending on the sequence. Of the 41 supernumerary lesions visible only on the DL HASTE sequence, 38 (93%) were true-positives. CONCLUSION The DL HASTE sequence can be used to improve image quality and contrast and reduces artifacts, allowing the detection of more liver lesions than with the T2-weighted BLADE sequence. CLINICAL RELEVANCE STATEMENT The DL HASTE sequence is superior to the T2-weighted BLADE sequence for the detection of focal liver lesions and can be used in daily practice as a standard sequence. KEY POINTS • The half-Fourier acquisition single-shot turbo spin echo sequence with deep learning reconstruction (DL HASTE sequence) has better overall image quality, reduced artifacts (particularly motion artifacts), and improved contrast, allowing the detection of more liver lesions than with the T2-weighted BLADE sequence. • The acquisition time of the DL HASTE sequence is at least eight times faster (21 s) than that of the T2-weighted BLADE sequence (3-5 min). • The DL HASTE sequence could replace the conventional T2-weighted BLADE sequence to meet the growing indication for hepatic MRI in clinical practice, given its diagnostic and time-saving performance.
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Affiliation(s)
- Pierre Wary
- Department of Adult Radiology, CHRU de Nancy, 5 Rue du Morvan, 54500, Vandoeuvre-lès-Nancy, France.
| | - Gabriela Hossu
- Clinical Investigation Center Technological Innovation of Nancy, Inserm, CHRU de Nancy, Vandoeuvre-lès-Nancy, France
- Adaptive Diagnostic and Interventional Imaging, Inserm, CHRU de Nancy, Vandoeuvre-lès-Nancy, France
| | - Khalid Ambarki
- Siemens Healthcare, Siemens Healthcare SAS, Saint Denis, France
| | - Dominik Nickel
- Siemens Healthcare GmbH, MR Application Predevelopment, Erlangen, Germany
| | - Simon Arberet
- Siemens Healthineers, Digital Technology & Innovation, Princeton, NJ, USA
| | - Julien Oster
- Clinical Investigation Center Technological Innovation of Nancy, Inserm, CHRU de Nancy, Vandoeuvre-lès-Nancy, France
- Adaptive Diagnostic and Interventional Imaging, Inserm, CHRU de Nancy, Vandoeuvre-lès-Nancy, France
| | - Xavier Orry
- Department of Adult Radiology, CHRU de Nancy, 5 Rue du Morvan, 54500, Vandoeuvre-lès-Nancy, France
| | - Valérie Laurent
- Department of Adult Radiology, CHRU de Nancy, 5 Rue du Morvan, 54500, Vandoeuvre-lès-Nancy, France
- Adaptive Diagnostic and Interventional Imaging, Inserm, CHRU de Nancy, Vandoeuvre-lès-Nancy, France
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Marin-Castrillon DM, Lalande A, Leclerc S, Ambarki K, Morgant MC, Cochet A, Lin S, Bouchot O, Boucher A, Presles B. 4D segmentation of the thoracic aorta from 4D flow MRI using deep learning. Magn Reson Imaging 2023; 99:20-25. [PMID: 36621555 DOI: 10.1016/j.mri.2022.12.021] [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] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 12/24/2022] [Accepted: 12/31/2022] [Indexed: 01/07/2023]
Abstract
BACKGROUND 4D flow MRI allows the analysis of hemodynamic changes in the aorta caused by pathologies such as thoracic aortic aneurysms (TAA). For personalized management of TAA, new biomarkers are required to analyze the effect of fluid structure iteration which can be obtained from 4D flow MRI. However, the generation of these biomarkers requires prior 4D segmentation of the aorta. OBJECTIVE To develop an automatic deep learning model to segment the aorta in 4D from 4D flow MRI. METHODS Segmentation is addressed with a U-Net based segmentation model that treats each 4D flow MRI frame as an independent sample. Performance is measured with respect to Dice score (DS) and Hausdorff distance (HD). In addition, the maximum and minimum surface areas at the level of the ascending aorta are measured and compared with those obtained from cine-MRI. RESULTS The segmentation performance was 0.90 ± 0.02 for the DS and the mean HD was 9.58 ± 4.36 mm. A correlation coefficient of r = 0.85 was obtained for the maximum surface and r = 0.86 for the minimum surface between the 4D flow MRI and cine-MRI. CONCLUSION The proposed automatic approach of 4D aortic segmentation from 4D flow MRI seems to be accurate enough to contribute to the wider use of this imaging technique in the analysis of pathologies such as TAA.
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Affiliation(s)
| | - Alain Lalande
- Imaging and Artificial Vision Laboratory, EA 7535, University of Burgundy, Dijon 21000, France; Medical Imaging Department, University Hospital of Dijon, Dijon 21000, France
| | - Sarah Leclerc
- Imaging and Artificial Vision Laboratory, EA 7535, University of Burgundy, Dijon 21000, France
| | | | - Marie-Catherine Morgant
- Imaging and Artificial Vision Laboratory, EA 7535, University of Burgundy, Dijon 21000, France; Department of cardiovascular and thoracic surgery, University Hospital of Dijon, Dijon 21000, France
| | - Alexandre Cochet
- Imaging and Artificial Vision Laboratory, EA 7535, University of Burgundy, Dijon 21000, France; Medical Imaging Department, University Hospital of Dijon, Dijon 21000, France
| | - Siyu Lin
- Imaging and Artificial Vision Laboratory, EA 7535, University of Burgundy, Dijon 21000, France
| | - Olivier Bouchot
- Imaging and Artificial Vision Laboratory, EA 7535, University of Burgundy, Dijon 21000, France; Department of cardiovascular and thoracic surgery, University Hospital of Dijon, Dijon 21000, France
| | - Arnaud Boucher
- Imaging and Artificial Vision Laboratory, EA 7535, University of Burgundy, Dijon 21000, France
| | - Benoit Presles
- Imaging and Artificial Vision Laboratory, EA 7535, University of Burgundy, Dijon 21000, France.
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Verclytte S, Gnanih R, Verdun S, Feiweier T, Clifford B, Ambarki K, Pasquini M, Ding J. Ultrafast MRI using deep learning echoplanar imaging for a comprehensive assessment of acute ischemic stroke. Eur Radiol 2023; 33:3715-3725. [PMID: 36928567 DOI: 10.1007/s00330-023-09508-0] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 12/09/2022] [Accepted: 01/30/2023] [Indexed: 03/18/2023]
Abstract
OBJECTIVES Acute ischemic stroke (AIS) is an emergency requiring both fast and informative MR sequences. We aimed to assess the performance of an artificial intelligence-enhanced ultrafast (UF) protocol, compared to the reference protocol, in the AIS management. METHODS We included patients admitted in the emergency department for suspected AIS. Each patient underwent a 3-T MR protocol, including reference acquisitions of T2-FLAIR, DWI, and SWI (duration: 7 min 54 s) and their accelerated multishot EPI counterparts for T2-FLAIR and T2*, complemented by a single-shot EPI DWI (duration: 1 min 54 s). Two blinded neuroradiologists reviewed each dataset, assessing DWI (detection, location, number of acute lesions), FLAIR (vascular hyperintensities, visibility of acute lesions), and SWI/T2* (hemorrhagic transformation, thrombus). We compared the agreement between the diagnoses obtained with both protocols using kappa coefficients. RESULTS A total of 173 patients were included consecutively, of whom 80 with an AIS in DWI. We found an almost perfect agreement between the UF and reference protocols regarding the detection, distribution, number of AIS in DWI (κ = 0.98, 0.98, and 0.87 respectively), the presence of vascular hyperintensities, and the presence of a parenchymal hyperintensity in the AIS region in FLAIR (κ = 0.93 and 0.89 respectively). Agreement was substantial in T2*/SWI for thrombus detection, and fair for hemorrhagic transformation detection (κ = 0.64 and 0.38 respectively). Differential diagnoses were similarly detected by both protocols (κ = 1). CONCLUSIONS Our AI-enhanced ultrafast MRI protocol allowed an effective detection and characterization of both AIS and differential diagnoses in less than 2 min. KEY POINTS • The AI-enhanced ultrafast MRI protocol allowed an effective detection of acute stroke. • Characterization of stroke features with the UF protocol was equivalent to the reference sequences. • Differential diagnoses were detected similarly by the UF and reference protocols.
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Affiliation(s)
- Sebastien Verclytte
- Imaging Department, Lille Catholic Hospitals, Lille Catholic University, F-59000, Lille, France.
| | - Robin Gnanih
- Imaging Department, Lille Catholic Hospitals, Lille Catholic University, F-59000, Lille, France
| | - Stephane Verdun
- Biostatistics Department - Delegation for Clinical Research and Innovation, Lille Catholic Hospitals, Lille Catholic University, F-59000, Lille, France
| | | | | | | | - Marta Pasquini
- Department of Neurology, Lille Catholic Hospitals, Lille Catholic University, F-59000, Lille, France
| | - Juliette Ding
- Imaging Department, Lille Catholic Hospitals, Lille Catholic University, F-59000, Lille, France
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De Landro M, Giraudeau C, Verde J, Ambarki K, Korganbayev S, Wolf A, Odeen H, Saccomandi P. Characterization of susceptibility artifacts in magnetic resonance thermometry images during laser interstitial thermal therapy: dimension analysis and temperature error estimation. Phys Med Biol 2023; 68. [PMID: 36791467 DOI: 10.1088/1361-6560/acbc62] [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] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 02/15/2023] [Indexed: 02/17/2023]
Abstract
OBJECTIVE Laser interstitial thermal therapy (LITT) is a minimally invasive procedure used to treat a lesion through light irradiation and consequent temperature increase. Magnetic Resonance Thermometry Imaging (MRTI) provides a multidimensional measurement of the temperature inside the target thus enabling accurate monitoring of the zone of damage during the procedure. In proton resonance frequency shift-based thermometry, artifacts in the images may strongly interfere with the estimated temperature maps. In our work, after noticing the formation of the dipolar-behavior artifact linkable to magnetic susceptibility changes during in vivo LITT, an investigation of susceptibility artifacts in tissue-mimicking phantoms was implemented. APPROACH The artifact was characterized: (i) by measuring the area and total volume of error regions and their evolution during the treatment; and (ii) by comparison with temperature reference provided by three temperature sensing needles. Lastly, a strategy to avoid artifacts formation was devised by using the temperature-sensing needles to implement a temperature-controlled LITT. MAIN RESULTS The artifact appearance was associated with gas bubble formation and with unwanted treatment effects producing magnetic susceptibility changes when 2 W laser power was set. The analysis of the artifact's dimension demonstrated that in the sagittal plane the dipolar-shape artifact may consistently spread following the temperature trend until reaching a volume 8 times bigger than the ablated one. Also, the artifact shape is quite symmetric with respect to the laser tip. An absolute temperature error showing a negative Gaussian profile in the area of susceptibility artifact with values up to 64.4 °C was estimated. Conversely, a maximum error of 2.8 °C is measured in the area not-affected by artifacts and far from the applicator tip. Finally, by regulating laser power, susceptibility artifacts formation was avoided, and appreciable thermal damage was induced. SIGNIFICANCE Such findings may help in improving the MRTI-based guidance of thermal therapies.
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Affiliation(s)
- Martina De Landro
- Politecnico di Milano, Via Giuseppe La Masa, 1, Milano, 20156, ITALY
| | - Céline Giraudeau
- Institute of Image-Guided Surgery, Place de l'hopital, Strasbourg, 67091, FRANCE
| | - Juan Verde
- Institute of Image-Guided Surgery, Place de l'hopital, Strasbourg, 67091, FRANCE
| | - Khalid Ambarki
- Siemens Healthcare SAS, Saint-Danis, Saint-Danis, 93200, FRANCE
| | - Sanzhar Korganbayev
- Politecnico di Milano, Via Giuseppe La Masa, 1, Milano, Lombardia, 20156, ITALY
| | - Alexey Wolf
- Laboratory of Fiber Optics, Institute of Automation and Electrometry of the SB RAS, Academician Koptyug Ave., Novosibirsk, 630099, RUSSIAN FEDERATION
| | - Henrik Odeen
- Department of Radiology and Imaging Science, University of Utah Health, Salt Lake City, Salt Lake City, Utah, 84132-0002, UNITED STATES
| | - Paola Saccomandi
- Dipartimento di Meccanica , Politecnico di Milano Dipartimento di Meccanica, Via Giuseppe La Masa, 1, Milano, 20156, ITALY
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Avila F, Caron B, Hossu G, Ambarki K, Kannengiesser S, Odille F, Felblinger J, Danese S, Choukour M, Laurent V, Peyrin-Biroulet L. Magnetic Resonance Elastography for Assessing Fibrosis in Patients with Crohn's Disease: A Pilot Study. Dig Dis Sci 2022; 67:4518-4524. [PMID: 34802092 DOI: 10.1007/s10620-021-07311-9] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 11/01/2021] [Indexed: 02/08/2023]
Abstract
BACKGROUND Patients with Crohn's disease can develop intestinal strictures, containing various degrees of inflammation and fibrosis. Differentiation of the main component of a stricturing lesion is the key for defining the therapeutic management. AIMS We assessed for the first time the accuracy of magnetic resonance elastography in detecting intestinal fibrosis and predicting clinical course in patients with Crohn's disease. METHODS This was a prospective study of adult patients with Crohn's disease and magnetic resonance imaging examination, including magnetic resonance elastography, between April 2019 and February 2020. The association between the bowel stiffness value and the degree of fibrosis was evaluated. The relationship between the stiffness value and the occurrence of clinical events was also investigated. RESULTS A total of 69 patients were included. The stiffness value measured by magnetic resonance elastography was correlated with the degree of fibrosis (p < 0.001). A bowel stiffness ≥ 3.57 kPa predicted the occurrence of clinical events with an area under the curve of 0.82 (95% CI 0.71-0.93). Bowel stiffness ≥ 3.57 kPa was associated with an increased risk of clinical events (p < 0.0001). CONCLUSION In Crohn's disease, magnetic resonance elastography is a reliable tool for detecting intestinal fibrosis and predicting a worse disease outcome.
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Affiliation(s)
- François Avila
- Department of Radiology, University Hospital of Nancy, Vandœuvre-lès-Nancy, France
| | - Bénédicte Caron
- Department of Gastroenterology and NGERE, U1256 INSERM, University Hospital of Nancy, Vandoeuvre-lès-Nancy, France
| | - Gabriela Hossu
- CIC 1433 Innovation Technologique, INSERM, Université de Lorraine, , CHRU Nancy, Nancy, France.,IADI, U12454, INSERM, Université de Lorraine, CHRU Nancy, Nancy, France
| | | | | | - Freddy Odille
- CIC 1433 Innovation Technologique, INSERM, Université de Lorraine, , CHRU Nancy, Nancy, France.,IADI, U12454, INSERM, Université de Lorraine, CHRU Nancy, Nancy, France
| | - Jacques Felblinger
- CIC 1433 Innovation Technologique, INSERM, Université de Lorraine, , CHRU Nancy, Nancy, France.,IADI, U12454, INSERM, Université de Lorraine, CHRU Nancy, Nancy, France
| | - Silvio Danese
- Gastroenterology and Endoscopy, IRCCS Ospedale San Raffaele and University Vita-Salute San Raffaele, Milano, Italy
| | - Myriam Choukour
- Department of Gastroenterology and NGERE, U1256 INSERM, University Hospital of Nancy, Vandoeuvre-lès-Nancy, France
| | - Valérie Laurent
- Department of Radiology, University Hospital of Nancy, Vandœuvre-lès-Nancy, France.,IADI, U12454, INSERM, Université de Lorraine, CHRU Nancy, Nancy, France
| | - Laurent Peyrin-Biroulet
- Department of Gastroenterology and NGERE, U1256 INSERM, University Hospital of Nancy, Vandoeuvre-lès-Nancy, France.
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De Landro M, Pietra FL, Pagotto SM, Porta L, Staiano I, Giraudeau C, Verde J, Ambarki K, Bianchi L, Korganbayev S, Odeen H, Gallix B, Saccomandi P. Analysis of cavitation artifacts in Magnetic Resonance Imaging Thermometry during laser ablation monitoring. Annu Int Conf IEEE Eng Med Biol Soc 2022; 2022:5008-5011. [PMID: 36085902 DOI: 10.1109/embc48229.2022.9871675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Magnetic Resonance Thermometry Imaging (MRTI) holds great potential in laser ablation (LA) monitoring. It provides the real-time multidimensional visualization of the treatment effect inside the body, thus enabling accurate intraoperative prediction of the thermal damage induced. Despite its great potential., thermal maps obtained with MRTI may be affected by numerous artifacts. Among the sources of error producing artifacts in the images., the cavitation phenomena which could occur in the tissue during LA induces dipole-structured artifacts. In this work., an analysis of the cavitation artifacts occurring during LA in a gelatin phantom in terms of symmetry in space and symmetry of temperature values was performed. Results of 2 Wand 4 W laser power were compared finding higher symmetry for the 2 W case in terms of both dimensions of artifact-lobes and difference in temperature values extracted in specular pixels in the image. This preliminary investigation of artifact features may provide a step forward in the identification of the best strategy to correct and avoid artifact occurrence during thermal therapy monitoring. Clinical Relevance- This work presents an analysis of cavitation artifacts in MRTI from LA which must be corrected to avoid error in the prediction of thermal damage during LA monitoring.
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Mulé S, Kharrat R, Zerbib P, Massire A, Nickel MD, Ambarki K, Reizine E, Baranes L, Zegai B, Pigneur F, Kobeiter H, Luciani A. Fast T2-weighted liver MRI: Image quality and solid focal lesions conspicuity using a deep learning accelerated single breath-hold HASTE fat-suppressed sequence. Diagn Interv Imaging 2022; 103:479-485. [PMID: 35597761 DOI: 10.1016/j.diii.2022.05.001] [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] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 04/27/2022] [Accepted: 05/02/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE Acceleration of MRI acquisitions and especially of T2-weighted sequences is essential to reduce the duration of MRI examinations but also kinetic artifacts in liver imaging. The purpose of this study was to compare the acquisition time and the image quality of a single-shot fat-suppressed turbo spin-echo (TSE) T2-weighted sequence with deep learning reconstruction (HASTEDL) with that of a fat-suppressed T2-weighted BLADE TSE sequence in patients with focal liver lesions. MATERIALS AND METHODS Ninety-five patients (52 men, 43 women; mean age: 61 ± 14 [SD]; age range: 28-87 years) with 42 focal liver lesions (17 hepatocellular carcinomas, 10 sarcoidosis lesions, 9 myeloma lesions, 3 liver metastases and 3 focal nodular hyperplasias) who underwent liver MRI at 1.5 T including HASTEDL and BLADE sequences were retrospectively included. Overall image quality, noise level in the liver, lesion conspicuity and sharpness of liver lesion contours were assessed by two independent readers. Liver signal-to-noise ratio (SNR) and lesion contrast-to-noise ratio (CNR) were measured and compared between the two sequences, as well as the mean duration of the sequences (Student t-test or Wilcoxon test for paired data). RESULTS Median overall quality on HASTEDL images (3; IQR: 3, 3) was significantly greater than that on BLADE images (2; IQR: 1, 3) (P < 0.001). Median noise level in the liver on HASTEDL images (0; IQR: 0, 0.5) was significantly lower than that on BLADE images (1; IQR: 1, 2) (P < 0.001). On HASTEDL images, mean liver SNR (107.3 ± 39.7 [SD]) and mean focal liver lesion CNR (87.0 ± 76.6 [SD]) were significantly greater than those on BLADE images (67.1 ± 23.8 [SD], P < 0.001 and 48.6 ± 43.9 [SD], P = 0.027, respectively). Acquisition time was significantly shorter with the HASTEDL sequence (18 ± [0] s; range: 18-18 s) compared to BLADE sequence (152 ± 47 [SD] s; range: 87-263 s) (P < 0.001). CONCLUSION By comparison with the BLADE sequence, HASTEDL sequence significantly reduces acquisition time while improving image quality, liver SNR and focal liver lesions CNR.
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Affiliation(s)
- Sébastien Mulé
- Service d'Imagerie Médicale, AP-HP, Hôpitaux Universitaires Henri Mondor, Créteil 94000, France; Faculté de Santé, Université Paris Est Créteil, Créteil 94000, France; INSERM IMRB, U 955, Equipe 18, Créteil 94000, France.
| | - Rym Kharrat
- Service d'Imagerie Médicale, AP-HP, Hôpitaux Universitaires Henri Mondor, Créteil 94000, France
| | - Pierre Zerbib
- Service d'Imagerie Médicale, AP-HP, Hôpitaux Universitaires Henri Mondor, Créteil 94000, France
| | | | | | | | - Edouard Reizine
- Service d'Imagerie Médicale, AP-HP, Hôpitaux Universitaires Henri Mondor, Créteil 94000, France; Faculté de Santé, Université Paris Est Créteil, Créteil 94000, France; INSERM IMRB, U 955, Equipe 18, Créteil 94000, France
| | - Laurence Baranes
- Service d'Imagerie Médicale, AP-HP, Hôpitaux Universitaires Henri Mondor, Créteil 94000, France
| | - Benhalima Zegai
- Service d'Imagerie Médicale, AP-HP, Hôpitaux Universitaires Henri Mondor, Créteil 94000, France
| | - Frederic Pigneur
- Service d'Imagerie Médicale, AP-HP, Hôpitaux Universitaires Henri Mondor, Créteil 94000, France
| | - Hicham Kobeiter
- Service d'Imagerie Médicale, AP-HP, Hôpitaux Universitaires Henri Mondor, Créteil 94000, France; Faculté de Santé, Université Paris Est Créteil, Créteil 94000, France
| | - Alain Luciani
- Service d'Imagerie Médicale, AP-HP, Hôpitaux Universitaires Henri Mondor, Créteil 94000, France; Faculté de Santé, Université Paris Est Créteil, Créteil 94000, France; INSERM IMRB, U 955, Equipe 18, Créteil 94000, France
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10
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Lersy F, Bund C, Anheim M, Mondino M, Noblet V, Lazzara S, Phillipps C, Collange O, Oulehri W, Mertes PM, Helms J, Merdji H, Schenck M, Schneider F, Pottecher J, Giraudeau C, Chammas A, Ardellier FD, Baloglu S, Ambarki K, Namer IJ, Kremer S. Evolution of Neuroimaging Findings in Severe COVID-19 Patients with Initial Neurological Impairment: An Observational Study. Viruses 2022; 14:949. [PMID: 35632691 PMCID: PMC9145920 DOI: 10.3390/v14050949] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/26/2022] [Accepted: 04/26/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Cerebral complications related to the COVID-19 were documented by brain MRIs during the acute phase. The purpose of the present study was to describe the evolution of these neuroimaging findings (MRI and FDG-PET/CT) and describe the neurocognitive outcomes of these patients. METHODS During the first wave of the COVID-19 outbreak between 1 March and 31 May 2020, 112 consecutive COVID-19 patients with neurologic manifestations underwent a brain MRI at Strasbourg University hospitals. After recovery, during follow-up, of these 112 patients, 31 (initially hospitalized in intensive care units) underwent additional imaging studies (at least one brain MRI). RESULTS Twenty-three men (74%) and eight women (26%) with a mean age of 61 years (range: 18-79) were included. Leptomeningeal enhancement, diffuse brain microhemorrhages, acute ischemic strokes, suspicion of cerebral vasculitis, and acute inflammatory demyelinating lesions were described on the initial brain MRIs. During follow-up, the evolution of the leptomeningeal enhancement was discordant, and the cerebral microhemorrhages were stable. We observed normalization of the vessel walls in all patients suspected of cerebral vasculitis. Four patients (13%) demonstrated new complications during follow-up (ischemic strokes, hypoglossal neuritis, marked increase in the white matter FLAIR hyperintensities with presumed vascular origin, and one suspected case of cerebral vasculitis). Concerning the grey matter volumetry, we observed a loss of volume of 3.2% during an average period of approximately five months. During follow-up, the more frequent FDG-PET/CT findings were hypometabolism in temporal and insular regions. CONCLUSION A minority of initially severe COVID-19 patients demonstrated new complications on their brain MRIs during follow-up after recovery.
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Affiliation(s)
- François Lersy
- Service d’Imagerie 2, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (F.L.); (A.C.); (F.-D.A.); (S.B.)
| | - Caroline Bund
- ICANS, Service de Médecine Nucléaire, 67000 Strasbourg, France; (C.B.); (I.J.N.)
- Engineering Science, Computer Science and Imaging Laboratory (ICube), Integrative Multimodal Imaging in Healthcare, University of Strasbourg-CNRS, UMR 7357, CEDEX, 67000 Strasbourg, France; (M.M.); (V.N.); (S.L.)
| | - Mathieu Anheim
- Service de Neurologie, Hôpitaux Universitaires de Strasbourg, 1 Avenue Molière, CEDEX, 67200 Strasbourg, France; (M.A.); (C.P.)
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM-U964/CNRS-UMR7104/Université de Strasbourg, 67400 Illkirch, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), UR 3072, Université de Strasbourg, 67000 Strasbourg, France;
| | - Mary Mondino
- Engineering Science, Computer Science and Imaging Laboratory (ICube), Integrative Multimodal Imaging in Healthcare, University of Strasbourg-CNRS, UMR 7357, CEDEX, 67000 Strasbourg, France; (M.M.); (V.N.); (S.L.)
| | - Vincent Noblet
- Engineering Science, Computer Science and Imaging Laboratory (ICube), Integrative Multimodal Imaging in Healthcare, University of Strasbourg-CNRS, UMR 7357, CEDEX, 67000 Strasbourg, France; (M.M.); (V.N.); (S.L.)
| | - Shirley Lazzara
- Engineering Science, Computer Science and Imaging Laboratory (ICube), Integrative Multimodal Imaging in Healthcare, University of Strasbourg-CNRS, UMR 7357, CEDEX, 67000 Strasbourg, France; (M.M.); (V.N.); (S.L.)
| | - Clelie Phillipps
- Service de Neurologie, Hôpitaux Universitaires de Strasbourg, 1 Avenue Molière, CEDEX, 67200 Strasbourg, France; (M.A.); (C.P.)
| | - Olivier Collange
- Service d’Anesthésie-Réanimation, Nouvel Hôpital Civil, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (O.C.); (W.O.); (P.-M.M.)
| | - Walid Oulehri
- Service d’Anesthésie-Réanimation, Nouvel Hôpital Civil, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (O.C.); (W.O.); (P.-M.M.)
| | - Paul-Michel Mertes
- Service d’Anesthésie-Réanimation, Nouvel Hôpital Civil, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (O.C.); (W.O.); (P.-M.M.)
| | - Julie Helms
- Service de Médecine Intensive-Réanimation, Nouvel Hôpital Civil, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (J.H.); (H.M.)
- INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative Nanomedicine (RNM), CRBS (Centre de Recherche en Biomédecine de Strasbourg), FMTS (Fédération de Médecine Translationnelle de Strasbourg), Faculty of Medicine, University of Strasbourg, 67000 Strasbourg, France
| | - Hamid Merdji
- Service de Médecine Intensive-Réanimation, Nouvel Hôpital Civil, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (J.H.); (H.M.)
| | - Maleka Schenck
- Service de Médecine Intensive Réanimation, Hôpitaux Universitaires de Strasbourg, Hautepierre, 67000 Strasbourg, France; (M.S.); (F.S.)
| | - Francis Schneider
- Service de Médecine Intensive Réanimation, Hôpitaux Universitaires de Strasbourg, Hautepierre, 67000 Strasbourg, France; (M.S.); (F.S.)
| | - Julien Pottecher
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), UR 3072, Université de Strasbourg, 67000 Strasbourg, France;
- Service d’Anesthésie-Réanimation et Médecine Péri-Opératoire, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France
| | - Céline Giraudeau
- Department of Radiology, IHU Strasbourg, 67000 Strasbourg, France;
| | - Agathe Chammas
- Service d’Imagerie 2, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (F.L.); (A.C.); (F.-D.A.); (S.B.)
| | - François-Daniel Ardellier
- Service d’Imagerie 2, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (F.L.); (A.C.); (F.-D.A.); (S.B.)
- Engineering Science, Computer Science and Imaging Laboratory (ICube), Integrative Multimodal Imaging in Healthcare, University of Strasbourg-CNRS, UMR 7357, CEDEX, 67000 Strasbourg, France; (M.M.); (V.N.); (S.L.)
| | - Seyyid Baloglu
- Service d’Imagerie 2, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (F.L.); (A.C.); (F.-D.A.); (S.B.)
| | - Khalid Ambarki
- Siemens Healthcare, Siemens Healthcare SAS, 67200 Saint Denis, France;
| | - Izzie Jacques Namer
- ICANS, Service de Médecine Nucléaire, 67000 Strasbourg, France; (C.B.); (I.J.N.)
- Engineering Science, Computer Science and Imaging Laboratory (ICube), Integrative Multimodal Imaging in Healthcare, University of Strasbourg-CNRS, UMR 7357, CEDEX, 67000 Strasbourg, France; (M.M.); (V.N.); (S.L.)
| | - Stéphane Kremer
- Service d’Imagerie 2, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (F.L.); (A.C.); (F.-D.A.); (S.B.)
- Engineering Science, Computer Science and Imaging Laboratory (ICube), Integrative Multimodal Imaging in Healthcare, University of Strasbourg-CNRS, UMR 7357, CEDEX, 67000 Strasbourg, France; (M.M.); (V.N.); (S.L.)
- Department of Radiology, IHU Strasbourg, 67000 Strasbourg, France;
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11
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Ding J, Gnanih R, Mackowiak A, Clifford B, Feiweier T, Colas L, Lacoste M, Ambarki K, Verclytte S. Evaluation de séquences ultra-rapides d'irm dans la prise en charge en urgence de l'avc en phase aigüe. J Neuroradiol 2022. [DOI: 10.1016/j.neurad.2022.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Zavard G, Catanzariti JF, Lacoste M, Ambarki K, Verdun S, Catala M, Thevenon A, TIFFREAU V, Verclytte S. Etude medulloscol: evaluation du flux du liquide cerebrospinal par imagerie par resonance magnetique nucleaire dans la scoliose idiopathique de l'adolescence. J Neuroradiol 2022. [DOI: 10.1016/j.neurad.2022.01.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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13
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Kristiansen M, Lindén C, Qvarlander S, Wåhlin A, Ambarki K, Hallberg P, Eklund A, Jóhannesson G. Feasibility of MRI to assess differences in ophthalmic artery blood flow rate in normal tension glaucoma and healthy controls. Acta Ophthalmol 2021; 99:e679-e685. [PMID: 33210819 PMCID: PMC8451810 DOI: 10.1111/aos.14673] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 10/05/2020] [Accepted: 10/14/2020] [Indexed: 11/30/2022]
Abstract
Purpose To examine feasibility of phase‐contrast magnetic resonance imaging (PCMRI) and to assess blood flow rate in the ophthalmic artery (OA) in patients with normal tension glaucoma (NTG) compared with healthy controls. Methods Sixteen patients with treated NTG and 16 age‐ and sex‐matched healthy controls underwent PCMRI using a 3‐Tesla scanner and ophthalmological examinations. OA blood flow rate was measured using a 2D PCMRI sequence with a spatial resolution of 0.35 mm2. Results The blood flow rate in the NTG group was 9.6 ± 3.9 ml/min [mean ± SD] compared with 11.9 ± 4.8 ml/min in the control group. Resistance Index (RI) and Pulsatility Index (PI) were 0.73 ± 0.08 and 1.36 ± 0.29, respectively, in the NTG group and 0.68 ± 0.13 and 1.22 ± 0.40, respectively, in the healthy group. The mean visual field index (VFI) was 46% ± 25 for the worse NTG eyes. The measured differences observed between the NTG group and the control group in blood flow rate (p = 0.12), RI (p = 0.18) and PI (p = 0.27) were non‐significant. Conclusions This case–control study, using PCMRI, showed a slight, but non‐significant, reduction in OA blood flow rate in the NTG patients compared with the healthy controls. These results indicate that blood flow may be of importance in the pathogenesis of NTG. Considering that only a limited portion of the total OA blood flow supplies the ocular system and the large inter‐individual differences, a larger study or more advanced PCMRI technique might give the answer.
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Affiliation(s)
- Martin Kristiansen
- Department of Clinical Sciences Ophthalmology Umeå University Umeå Sweden
| | - Christina Lindén
- Department of Clinical Sciences Ophthalmology Umeå University Umeå Sweden
| | - Sara Qvarlander
- Department of Radiation Sciences Biomedical Engineering Umeå University Umeå Sweden
- Centre for Biomedical Engineering and Physics Umeå University Umeå Sweden
| | - Anders Wåhlin
- Department of Radiation Sciences Biomedical Engineering Umeå University Umeå Sweden
- Centre for Biomedical Engineering and Physics Umeå University Umeå Sweden
- Umeå Center for Functional Brain Imaging Umeå University Umeå Sweden
| | - Khalid Ambarki
- Department of Radiation Sciences Biomedical Engineering Umeå University Umeå Sweden
- Centre for Biomedical Engineering and Physics Umeå University Umeå Sweden
| | - Per Hallberg
- Centre for Biomedical Engineering and Physics Umeå University Umeå Sweden
- Dept. of Applied Physics and Electronics Umeå University Umeå Sweden
| | - Anders Eklund
- Department of Radiation Sciences Biomedical Engineering Umeå University Umeå Sweden
- Centre for Biomedical Engineering and Physics Umeå University Umeå Sweden
| | - Gauti Jóhannesson
- Department of Clinical Sciences Ophthalmology Umeå University Umeå Sweden
- Wallenberg Center for Molecular Medicine Umeå University Umeå Sweden
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Blaise H, Remen T, Ambarki K, Weiland E, Kuehn B, Orry X, Laurent V. Comparison of respiratory-triggered 3D MR cholangiopancreatography and breath-hold compressed-sensing 3D MR cholangiopancreatography at 1.5 T and 3 T and impact of individual factors on image quality. Eur J Radiol 2021; 142:109873. [PMID: 34371309 DOI: 10.1016/j.ejrad.2021.109873] [Citation(s) in RCA: 3] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 07/02/2021] [Accepted: 07/20/2021] [Indexed: 12/20/2022]
Abstract
PURPOSE To evaluate the image quality of an accelerated compressed-sensing single-breath-hold 3D magnetic resonance cholangiopancreatography (BH-CS-MRCP) prototype sequence compared to the standard 3D sequence with respiratory triggering (STD-MRCP) at 1.5 T and 3 T. To assess the individual factors that can affect image quality. METHOD This is a retrospective analysis. Both sequences (BH-CS-MRCP and STD-MRCP) were performed in 200 patients at 1.5 T and 200 patients at 3 T. Overall image quality and the visualization of the bilio-pancreatic ducts were rated on a 5-point scale. Image sharpness and background suppression were rated on a 4-point scale. A double reading was performed in 50 patients to assess the inter-observer reproducibility. Individual characteristics studied were gender, age, BMI, ascites, abdominal surface and breath-hold quality. RESULTS At 1.5 T, BH-CS-MRCP was inferior to STD-MRCP in terms of overall quality (p = 0.0046), background suppression (p < 0.0001), visualization of the cystic duct (p < 0.0001), the right bile duct (p = 0.0008), the left bile duct (p = 0.0152), and the main pancreatic duct (p < 0.0001). However, BH-CS-MRCP was sharper than STD-MRCP (p = 0.028). At 3 T, BH-CS-MRCP was superior to STD-MRCP for overall quality (p < 0.0001), sharpness (p < 0.0001), and visualization of the bilio-pancreatic ducts (p < 0.0001). Background signal was conversely better suppressed in STD-MRCP (p < 0.0001). At 1.5 T, the volume of ascites was inversely correlated with image quality for BH-CS-MRCP while BMI was inversely correlated with image quality for STD-MRCP. Breath-hold quality was correlated with image quality for BH-CS-MRCP at 1.5 T and 3 T. CONCLUSION BH-CS-MRCP is feasible in clinical routine at 1.5 and 3 T, yielding significantly better perceived image quality at 3 T but not at 1.5 T. BH-CS-MRCP appears to be influenced by ascites whereas STD-MRCP is influenced by BMI at 1.5 T. This study was approved by the Ethics Review Board for Research in Medical Imaging (IRB: CRM-2003-065).
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Affiliation(s)
- Hélène Blaise
- Brabois Imaging Department, Nancy University Hospital, Université de Lorraine, Allée du Morvan 54500 Vandœuvre-lès-Nancy, France.
| | - Thomas Remen
- Unity of Methodology and Data Management, Nancy University Hospital, Vandœuvre-Lès-Nancy, France
| | | | | | | | - Xavier Orry
- Brabois Imaging Department, Nancy University Hospital, Université de Lorraine, Allée du Morvan 54500 Vandœuvre-lès-Nancy, France
| | - Valérie Laurent
- Brabois Imaging Department, Nancy University Hospital, Université de Lorraine, Allée du Morvan 54500 Vandœuvre-lès-Nancy, France
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Pelissier M, Ambarki K, Salleron J, Henrot P. Maximum slope using ultrafast breast DCE-MRI at 1.5 Tesla: a potential tool for predicting breast lesion aggressiveness. Eur Radiol 2021; 31:9556-9566. [PMID: 34117556 DOI: 10.1007/s00330-021-08089-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 01/23/2021] [Revised: 04/09/2021] [Accepted: 05/21/2021] [Indexed: 01/01/2023]
Abstract
OBJECTIVES We evaluated the relationship between the maximum slope (MS) based on ultrafast breast DCE-MRI sequences, and the clinical parameters and routine prognostic factors of breast cancer. METHODS 210 lesions were retrospectively evaluated: 150 malignant (30 each of luminal A invasive carcinoma, luminal B invasive carcinoma, HER2 overexpression (HER2), triple negative (TN), invasive lobular carcinoma (ILC)), and 60 benign. For each lesion, the MS was obtained with an ultrafast sequence and semi-quantitative curves were classified into three types with a conventional DCE sequence. The correlation between MS and age, body mass index (BMI), menopause, and routine prognostic factors were analyzed. RESULTS A MS cut-off at 6.5%/s could discriminate benign from malignant lesions, with sensitivity and specificity of 84% and 90%, respectively, whereas analysis of semi-quantitative curves showed sensitivity and specificity of 89.3% and 55%, respectively. In multivariate analysis, MS values decreased with BMI increasing (p = 0.035), postmenopausal status (p < 0.001), and positive ER status (p < 0.001) and increased with tumor size (p < 0.001). The MS was significantly lower for the pooled luminal A + ILC group than for the pooled luminal B + HER2 + TN group featuring tumors with poorer prognoses (p < 0.001). With a threshold of 11%/s, the sensitivity and specificity to identify invasive carcinoma subtypes with poorer prognoses were 71% and 68%, respectively. CONCLUSION The MS allows better tumor characterization and identifies factors of poor prognosis for breast cancer. KEY POINTS • Maximum slope calculated from ultrafast breast DCE-MRI differentiates benign from malignant breast lesions better than semi-quantitative curves of conventional DCE-MRI. • Maximum slope calculated from ultrafast breast DCE-MRI identifies breast cancers with poor prognoses. • In the case of multiple lesions, the most aggressive may be identified and targeted by measuring the maximum slope.
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Affiliation(s)
- Margaux Pelissier
- Department of Radiology, Institut de Cancérologie de Lorraine, 6 avenue de Bourgogne, 54 519, Vandoeuvre-les-Nancy, France
| | - Khalid Ambarki
- Siemens Healthcare GmbH, Siemens Healthcare SAS, Saint Denis, France
| | - Julia Salleron
- Department of Biostatistics, Institut de Cancérologie de Lorraine, 6 avenue de Bourgogne, 54 519, Vandoeuvre-les-Nancy, France
| | - Philippe Henrot
- Department of Radiology, Institut de Cancérologie de Lorraine, 6 avenue de Bourgogne, 54 519, Vandoeuvre-les-Nancy, France.
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Chatelin S, Pop R, Giraudeau C, Ambarki K, Jin N, Séverac F, Breton E, Vappou J. Influence of portal vein occlusion on portal flow and liver elasticity in an animal model. NMR Biomed 2021; 34:e4498. [PMID: 33634498 DOI: 10.1002/nbm.4498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 09/02/2020] [Accepted: 02/11/2021] [Indexed: 06/12/2023]
Abstract
Hepatic fibrosis causes an increase in liver stiffness, a parameter measured by elastography and widely used as a diagnosis method. The concomitant presence of portal vein thrombosis (PVT) implies a change in hepatic portal inflow that could also affect liver elasticity. The main objective of this study is to determine the extent to which the presence of portal occlusion can affect the mechanical properties of the liver and potentially lead to misdiagnosis of fibrosis and hepatic cirrhosis by elastography. Portal vein occlusion was generated by insertion and inflation of a balloon catheter in the portal vein of four swines. The portal flow parameters peak flow (PF) and peak velocity magnitude (PVM) and liver mechanical properties (shear modulus) were then investigated using 4D-flow MRI and MR elastography, respectively, for progressive obstructions of the portal vein. Experimental results indicate that the reduction of the intrahepatic venous blood flow (PF/PVM decreases of 29.3%/8.5%, 51.0%/32.3% and 83.3%/53.6%, respectively) measured with 50%, 80% and 100% obstruction of the portal vein section results in a decrease of liver stiffness by 0.8% ± 0.1%, 7.7% ± 0.4% and 12.3% ± 0.9%, respectively. While this vascular mechanism does not have sufficient influence on the elasticity of the liver to modify the diagnosis of severe fibrosis or cirrhosis (F4 METAVIR grade), it may be sufficient to attenuate the increase in stiffness due to moderate fibrosis (F2-F3 METAVIR grades) and consequently lead to false-negative diagnoses with elastography in the presence of PVT.
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Affiliation(s)
- Simon Chatelin
- ICube, CNRS UMR 7357, University of Strasbourg, Strasbourg, France
| | - Raoul Pop
- IHU-Strasbourg, Institute for Image-Guided Surgery, Strasbourg, France
- Interventional Neuroradiology Department, University Hospital of Strasbourg, Strasbourg, France
| | - Céline Giraudeau
- IHU-Strasbourg, Institute for Image-Guided Surgery, Strasbourg, France
| | | | - Ning Jin
- Siemens Medical Solutions USA, Inc., Chicago, Illinois, USA
| | - François Séverac
- ICube, CNRS UMR 7357, University of Strasbourg, Strasbourg, France
- Public Healthcare Department, University Hospitals Strasbourg, Strasbourg, France
| | - Elodie Breton
- ICube, CNRS UMR 7357, University of Strasbourg, Strasbourg, France
| | - Jonathan Vappou
- ICube, CNRS UMR 7357, University of Strasbourg, Strasbourg, France
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Zarrinkoob L, Wåhlin A, Ambarki K, Eklund A, Malm J. Quantification and mapping of cerebral hemodynamics before and after carotid endarterectomy, using four-dimensional flow magnetic resonance imaging. J Vasc Surg 2021; 74:910-920.e1. [PMID: 33812036 DOI: 10.1016/j.jvs.2021.01.074] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [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: 10/13/2020] [Accepted: 01/26/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Carotid stenosis can profoundly affect cerebral hemodynamics, which cannot simply be inferred from the degree of stenosis. We quantified and mapped the distribution of the blood flow rate (BFR) in the cerebral arteries before and after carotid endarterectomy using four-dimensional (4D) phase-contrast (PC) magnetic resonance imaging (MRI). METHODS Nineteen patients (age, 71 ± 6 years; 2 women) with symptomatic carotid stenosis (≥50%) undergoing carotid endarterectomy (CEA) were investigated using 4D PC-MRI before and after surgery. The BFR was measured in 17 cerebral arteries and the ophthalmic arteries. Collateral recruitment through the anterior and posterior communicating arteries, ophthalmic arteries, and leptomeningeal arteries was quantified. BFR laterality was significantly different between the paired contralateral and ipsilateral arteries. Subgroups were defined according to the presence of collateral recruitment. RESULTS The total cerebral blood flow had increased by 15% (P < .01) after CEA. Before CEA, laterality was seen in the internal carotid artery, anterior cerebral artery, and middle cerebral artery (MCA). On the ipsilateral side, an increased BFR was found after CEA in the internal carotid artery (246 ± 62 mL/min vs 135 ± 80 mL/min; P < .001), anterior cerebral artery (87 ± mL/min vs 38 ± 58 mL/min; P < .01), and MCA (149 ± 43 mL/min vs 119 ± 34 mL/min; P < .01), resulting in a postoperative BFR distribution without signs of laterality. In the nine patients with preoperatively recruited collaterals, BFR laterality was found in the MCA before, but not after, CEA (P < .01). This laterality was not found in the 10 patients without collateral recruitment (P = .2). The degree of stenosis did not differ between the groups with and without collateral recruitment (P = .85). CONCLUSIONS Using 4D PC-MRI, we have presented a comprehensive and noninvasive method to evaluate the cerebral hemodynamics due to carotid stenosis before and after CEA. MCA laterality, seen in the patients with collateral recruitment before CEA, pointed toward a hemodynamic disturbance in MCA territory for those patients. This methodologic advancement provides an insight into the pathophysiology of cerebral hemodynamics in patients with carotid stenosis.
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Affiliation(s)
- Laleh Zarrinkoob
- Division of Neuroscience, Department of Clinical Sciences, Umeå University, Umeå, Sweden; Department of Surgical and Perioperative Sciences, Umeå University, Umeå, Sweden.
| | - Anders Wåhlin
- Department of Radiation Sciences, Umeå University, Umeå, Sweden; Centre for Biomedical Engineering and Physics, Umeå University, Umeå, Sweden; Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
| | - Khalid Ambarki
- Department of Radiation Sciences, Umeå University, Umeå, Sweden; Centre for Biomedical Engineering and Physics, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden; Centre for Biomedical Engineering and Physics, Umeå University, Umeå, Sweden
| | - Jan Malm
- Division of Neuroscience, Department of Clinical Sciences, Umeå University, Umeå, Sweden
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Jóhannesson G, Qvarlander S, Wåhlin A, Ambarki K, Hallberg P, Eklund A, Lindén C. Intraocular Pressure Decrease Does Not Affect Blood Flow Rate of Ophthalmic Artery in Ocular Hypertension. Invest Ophthalmol Vis Sci 2020; 61:17. [PMID: 33074299 PMCID: PMC7585392 DOI: 10.1167/iovs.61.12.17] [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] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Purpose To investigate if decrease of IOP affects the volumetric blood flow rate in the ophthalmic artery (OA) in patients with previously untreated ocular hypertension. Methods Subjects with untreated ocular hypertension (n = 30; mean age 67 ± 8 years; 14 females) underwent ophthalmologic examination and a 3-Tesla magnetic resonance imaging investigation. The magnetic resonance imaging included three-dimensional high-resolution phase-contrast magnetic resonance imaging to measure the OA blood flow rate. The subjects received latanoprost once daily in the eye with higher pressure, the untreated eye served as control. The same measurements were repeated approximately 1 week later. Results The mean OA blood flow rate before and after treatment was 12.4 ± 4.4 and 12.4 ± 4.6 mL/min in the treated eye (mean ± SD; P = 0.92) and 13.5 ± 5.2 and 13.4 ± 4.1 mL/min in the control eye (P = 0.92). There was no significant difference between the treated and control eye regarding blood flow rate before (P = 0.13) or after treatment (P = 0.18), or change in blood flow rate after treatment (0.1 ± 3.1 vs. -0.1 ± 4.0 mL/min, P = 0.84). Latanoprost decreased the IOP by 7.2 ± 3.1 mm Hg in the treated eye (P < 0.01). Conclusions The results indicate that a significant lowering of IOP does not affect the blood flow rate of the OA in ocular hypertension subjects. The ability to maintain blood supply to the eye independent of the IOP could be a protective mechanism in preserving vision in subjects with ocular hypertension.
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Affiliation(s)
- Gauti Jóhannesson
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden.,Wallenberg Center for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Sara Qvarlander
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden.,Centre for Biomedical Engineering and Physics, Umeå University, Umeå Sweden
| | - Anders Wåhlin
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden.,Centre for Biomedical Engineering and Physics, Umeå University, Umeå Sweden.,Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
| | - Khalid Ambarki
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Per Hallberg
- Centre for Biomedical Engineering and Physics, Umeå University, Umeå Sweden.,Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden.,Centre for Biomedical Engineering and Physics, Umeå University, Umeå Sweden
| | - Christina Lindén
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden
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Soullié P, Missoffe A, Ambarki K, Felblinger J, Odille F. MR electrical properties imaging using a generalized image-based method. Magn Reson Med 2020; 85:762-776. [PMID: 32783236 DOI: 10.1002/mrm.28458] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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: 02/18/2020] [Revised: 07/08/2020] [Accepted: 07/10/2020] [Indexed: 11/12/2022]
Abstract
PURPOSE To develop a fast and easy-to-use electrical properties tomography (EPT) method based on a single MR scan, avoiding both the need of a B1 -map and transceive phase assumption, and that is robust against noise. THEORY Derived from Maxwell's equations, conductivity, and permittivity are reconstructed from a new partial differential equation involving the product of the RF fields and its derivatives. This also allows us to clarify and revisit the relevance of common assumptions of MREPT. METHODS Our new governing equation is solved using a 3D finite-difference scheme and compared to previous frameworks. The benefits of our method over selected existing MREPT methods are demonstrated for different simulation models, as well as for both an inhomogeneous agar phantom gel and in vivo brain data at 3T. RESULTS Simulation and experimental results are illustrated to highlight the merits of the proposed method over existing methods. We show the validity of our algorithm in versatile configurations, with many transition regions notably. Complex admittivity maps are also provided as a complementary MR contrast. CONCLUSION Because it avoids time-consuming RF field mapping and generalizes the use of standard MR image for electrical properties reconstruction, this contribution is promising as a new step forward for clinical applications.
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Affiliation(s)
- Paul Soullié
- IADI, INSERM U1254, Université de Lorraine, Nancy, France
| | | | | | - Jacques Felblinger
- IADI, INSERM U1254, Université de Lorraine, Nancy, France.,CIC-IT 1433, INSERM, Université de Lorraine and CHRU de Nancy, Nancy, France
| | - Freddy Odille
- IADI, INSERM U1254, Université de Lorraine, Nancy, France.,CIC-IT 1433, INSERM, Université de Lorraine and CHRU de Nancy, Nancy, France
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20
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Zarrinkoob L, Wåhlin A, Ambarki K, Birgander R, Eklund A, Malm J. Blood Flow Lateralization and Collateral Compensatory Mechanisms in Patients With Carotid Artery Stenosis. Stroke 2020; 50:1081-1088. [PMID: 30943887 PMCID: PMC6485302 DOI: 10.1161/strokeaha.119.024757] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [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] [Indexed: 01/14/2023]
Abstract
Background and Purpose- Four-dimensional phase-contrast magnetic resonance imaging enables quantification of blood flow rate (BFR; mL/min) in multiple cerebral arteries simultaneously, making it a promising technique for hemodynamic investigation in patients with stroke. The aim of this study was to quantify the hemodynamic disturbance and the compensatory pattern of collateral flow in patients with symptomatic carotid stenosis. Methods- Thirty-eight patients (mean, 72 years; 27 men) with symptomatic carotid stenosis (≥50%) or occlusion were investigated using 4-dimensional phase-contrast magnetic resonance imaging. For each patient, BFR was measured in 19 arteries/locations. The ipsilateral side to the symptomatic carotid stenosis was compared with the contralateral side. Results- Internal carotid artery BFR was lower on the ipsilateral side (134±87 versus 261±95 mL/min; P<0.001). BFR in anterior cerebral artery (A1 segment) was lower on ipsilateral side (35±58 versus 119±72 mL/min; P<0.001). Anterior cerebral artery territory bilaterally was primarily supplied by contralateral internal carotid artery. The ipsilateral internal carotid artery mainly supplied the ipsilateral middle cerebral artery (MCA) territory. MCA was also supplied by a reversed BFR found in the ophthalmic and the posterior communicating artery routes on the ipsilateral side (-5±28 versus 10±28 mL/min, P=0.001, and -2±12 versus 6±6 mL/min, P=0.03, respectively). Despite these compensations, BFR in MCA was lower on the ipsilateral side, and this laterality was more pronounced in patients with severe carotid stenosis (≥70%). Although comparing ipsilateral MCA BFR between stenosis groups (<70% and ≥70%), there was no difference ( P=0.95). Conclusions- With a novel approach using 4-dimensional phase-contrast magnetic resonance imaging, we could simultaneously quantify and rank the importance of collateral routes in patients with carotid stenosis. An important observation was that contralateral internal carotid artery mainly secured the bilateral anterior cerebral artery territory. Because of the collateral recruitment, compromised BFR in MCA is not necessarily related to the degree of carotid stenosis. These findings highlight the importance of simultaneous investigation of the hemodynamics of the entire cerebral arterial tree.
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Affiliation(s)
- Laleh Zarrinkoob
- From the Department of Pharmacology and Clinical Neuroscience, Umeå, Sweden (L.Z., J.M.).,Department of Surgical and Perioperative Sciences, Umeå, Sweden (L.Z.)
| | - Anders Wåhlin
- Department of Radiation Science, Umeå, Sweden (A.W., K.A., R.B., A.E.).,Centre for Biomedical Engineering and Physics, Umeå, Sweden (A.W., K.A., A.E.).,Umeå Center for Functional Brain Imaging, Sweden (A.W., A.E.)
| | - Khalid Ambarki
- Department of Radiation Science, Umeå, Sweden (A.W., K.A., R.B., A.E.).,Centre for Biomedical Engineering and Physics, Umeå, Sweden (A.W., K.A., A.E.)
| | - Richard Birgander
- Department of Radiation Science, Umeå, Sweden (A.W., K.A., R.B., A.E.)
| | - Anders Eklund
- Department of Radiation Science, Umeå, Sweden (A.W., K.A., R.B., A.E.).,Centre for Biomedical Engineering and Physics, Umeå, Sweden (A.W., K.A., A.E.).,Umeå Center for Functional Brain Imaging, Sweden (A.W., A.E.)
| | - Jan Malm
- From the Department of Pharmacology and Clinical Neuroscience, Umeå, Sweden (L.Z., J.M.)
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21
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Edsbagge M, Andreasson U, Ambarki K, Wikkelsø C, Eklund A, Blennow K, Zetterberg H, Tullberg M. Alzheimer's Disease-Associated Cerebrospinal Fluid (CSF) Biomarkers do not Correlate with CSF Volumes or CSF Production Rate. J Alzheimers Dis 2018; 58:821-828. [PMID: 28505972 DOI: 10.3233/jad-161257] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Neuropathologically, Alzheimer's disease (AD) is characterized by accumulation of a 42 amino acid peptide called amyloid-β (Aβ42) in extracellular senile plaques together with intraneuronal inclusions of hyperphosphorylated tau protein in neurofibrillary tangles and neuronal degeneration. These changes are reflected in the cerebrospinal fluid (CSF), the volumes and production rates of which vary considerably between individuals, by reduced concentration of Aβ42, increased concentration of phosphorylated tau (P-tau) protein, and increased concentration of total tau (T-tau) protein, respectively. OBJECTIVE To examine the outstanding question if CSF concentrations of AD associated biomarkers are influenced by variations in CSF volumes, CSF production rate, and intracranial pressure in healthy individuals. METHODS CSF concentrations of Aβ42, P-tau, and T-tau, as well as a number of other AD-related CSF biomarkers were analyzed together with intracranial subarachnoid, ventricular, and spinal CSF volumes, as assessed by magnetic resonance imaging volumetric measurements, and CSF production rate in 19 cognitively normal healthy subjects (mean age 70.6, SD 3.6 years). RESULTS Negative correlations were seen between the concentrations of three CSF biomarkers (albumin ratio, Aβ38, and Aβ40), and ventricular CSF volume, but apart from this finding, no significant correlations were observed. CONCLUSION These results speak against inter-individual variations in CSF volume and production rate as important confounds in the AD biomarker research field.
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Affiliation(s)
- Mikael Edsbagge
- Department of Clinical Neuroscience, Hydrocephalus Research Unit, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Ulf Andreasson
- Department of Psychiatry and Neurochemistry, Clinical Neurochemistry Laboratory,Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Khalid Ambarki
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Carsten Wikkelsø
- Department of Clinical Neuroscience, Hydrocephalus Research Unit, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Clinical Neurochemistry Laboratory,Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Clinical Neurochemistry Laboratory,Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,UCL Institute of Neurology, Queen Square, London, UK
| | - Mats Tullberg
- Department of Clinical Neuroscience, Hydrocephalus Research Unit, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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22
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Qvarlander S, Ambarki K, Wåhlin A, Jacobsson J, Birgander R, Malm J, Eklund A. Cerebrospinal fluid and blood flow patterns in idiopathic normal pressure hydrocephalus. Acta Neurol Scand 2017; 135:576-584. [PMID: 27388230 DOI: 10.1111/ane.12636] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2016] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Increased aqueduct cerebrospinal fluid (CSF) flow pulsatility and, recently, a reversed CSF flow in the aqueduct have been suggested as hallmarks of idiopathic normal pressure hydrocephalus (INPH). However, these findings have not been adequately confirmed. Our objective was to investigate the flow of blood and CSF in INPH, as compared to healthy elderly, in order to clarify which flow parameters are related to the INPH pathophysiology. MATERIALS AND METHODS Sixteen INPH patients (73 years) and 35 healthy subjects (72 years) underwent phase-contrast magnetic resonance imaging (MRI). Measurements included aqueduct and cervical CSF flow, total arterial inflow (tCBF; i.e. carotid + vertebral arteries), and internal jugular vein flow. Flow pulsatility, net flow, and flow delays were compared (multiple linear regression, correcting for sex and age). RESULTS Aqueduct stroke volume was higher in INPH than healthy (148±95 vs 90±50 mL, P<.05). Net aqueduct CSF flow was similar in magnitude and direction. The cervical CSF stroke volume was lower (P<.05). The internal carotid artery net flow was lower in INPH (P<.05), although tCBF was not. No differences were found in internal jugular vein flow or flow delays. CONCLUSIONS The typical flow of blood and CSF in INPH was mainly characterized by increased CSF pulsatility in the aqueduct and reduced cervical CSF pulsatility. The direction of mean net aqueduct CSF flow was from the third to the fourth ventricle. Our findings may reflect the altered distribution of intracranial CSF volume in INPH, although the causality of these relationships is unclear.
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Affiliation(s)
- S. Qvarlander
- Department of Radiation Sciences; Umeå University; Umeå Sweden
- Centre for Biomedical Engineering and Physics; Umeå University; Umeå Sweden
| | - K. Ambarki
- Department of Radiation Sciences; Umeå University; Umeå Sweden
- Centre for Biomedical Engineering and Physics; Umeå University; Umeå Sweden
| | - A. Wåhlin
- Department of Radiation Sciences; Umeå University; Umeå Sweden
- Umeå Centre for Functional Brain Imaging; Umeå University; Umeå Sweden
| | - J. Jacobsson
- Department of Pharmacology and Clinical Neuroscience; Umeå University; Umeå Sweden
| | - R. Birgander
- Department of Radiation Sciences; Umeå University; Umeå Sweden
| | - J. Malm
- Department of Pharmacology and Clinical Neuroscience; Umeå University; Umeå Sweden
| | - A. Eklund
- Department of Radiation Sciences; Umeå University; Umeå Sweden
- Centre for Biomedical Engineering and Physics; Umeå University; Umeå Sweden
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23
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Vågberg M, Ambarki K, Lindqvist T, Birgander R, Svenningsson A. Brain parenchymal fraction in an age-stratified healthy population – determined by MRI using manual segmentation and three automated segmentation methods. J Neuroradiol 2016; 43:384-391. [DOI: 10.1016/j.neurad.2016.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/10/2016] [Accepted: 08/30/2016] [Indexed: 01/18/2023]
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Zarrinkoob L, Ambarki K, Wåhlin A, Birgander R, Carlberg B, Eklund A, Malm J. Aging alters the dampening of pulsatile blood flow in cerebral arteries. J Cereb Blood Flow Metab 2016; 36:1519-27. [PMID: 26823470 PMCID: PMC5012521 DOI: 10.1177/0271678x16629486] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [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: 10/25/2015] [Accepted: 12/28/2015] [Indexed: 01/13/2023]
Abstract
Excessive pulsatile flow caused by aortic stiffness is thought to be a contributing factor for several cerebrovascular diseases. The main purpose of this study was to describe the dampening of the pulsatile flow from the proximal to the distal cerebral arteries, the effect of aging and sex, and its correlation to aortic stiffness. Forty-five healthy elderly (mean age 71 years) and 49 healthy young (mean age 25 years) were included. Phase-contrast magnetic resonance imaging was used for measuring blood flow pulsatility index and dampening factor (proximal artery pulsatility index/distal artery pulsatility index) in 21 cerebral and extra-cerebral arteries. Aortic stiffness was measured as aortic pulse wave velocity. Cerebral arterial pulsatility index increased due to aging and this was more pronounced in distal segments of cerebral arteries. There was no difference in pulsatility index between women and men. Dampening of pulsatility index was observed in all cerebral arteries in both age groups but was significantly higher in young subjects than in elderly. Pulse wave velocity was not correlated with cerebral arterial pulsatility index. The increased pulsatile flow in elderly together with reduced dampening supports the pulse wave encephalopathy theory, since it implies that a higher pulsatile flow is reaching distal arterial segments in older subjects.
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Affiliation(s)
- Laleh Zarrinkoob
- Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden
| | - Khalid Ambarki
- Department of Radiation Sciences, Umeå University, Umeå, Sweden Centre for Biomedical Engineering and Physics, Umeå University, Umeå, Sweden
| | - Anders Wåhlin
- Department of Radiation Sciences, Umeå University, Umeå, Sweden Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
| | | | - Bo Carlberg
- Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden Centre for Biomedical Engineering and Physics, Umeå University, Umeå, Sweden
| | - Jan Malm
- Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden
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25
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Eklund A, Jóhannesson G, Johansson E, Holmlund P, Qvarlander S, Ambarki K, Wåhlin A, Koskinen LOD, Malm J. The pressure difference between eye and brain changes with posture. Ann Neurol 2016; 80:269-76. [DOI: 10.1002/ana.24713] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/27/2016] [Accepted: 06/27/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Anders Eklund
- Department of Radiation Sciences; Umeå University; Umeå Sweden
- Center for Biomedical Engineering and Physics; Umeå University; Umeå Sweden
| | - Gauti Jóhannesson
- Department of Clinical Science; Ophthalmology, Umeå University; Umeå Sweden
| | - Elias Johansson
- Department of Pharmacology and Clinical Neuroscience; Umeå University; Umeå Sweden
| | - Petter Holmlund
- Department of Radiation Sciences; Umeå University; Umeå Sweden
| | - Sara Qvarlander
- Department of Radiation Sciences; Umeå University; Umeå Sweden
| | - Khalid Ambarki
- Department of Radiation Sciences; Umeå University; Umeå Sweden
| | - Anders Wåhlin
- Department of Radiation Sciences; Umeå University; Umeå Sweden
- Umeå Center for Functional Brain Imaging; Umeå University; Umeå Sweden
| | - Lars-Owe D. Koskinen
- Department of Pharmacology and Clinical Neuroscience; Umeå University; Umeå Sweden
| | - Jan Malm
- Department of Pharmacology and Clinical Neuroscience; Umeå University; Umeå Sweden
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26
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Marshall-Goebel K, Ambarki K, Eklund A, Malm J, Mulder E, Gerlach D, Bershad E, Rittweger J. Effects of short-term exposure to head-down tilt on cerebral hemodynamics: a prospective evaluation of a spaceflight analog using phase-contrast MRI. J Appl Physiol (1985) 2016; 120:1466-73. [PMID: 27013606 PMCID: PMC4909835 DOI: 10.1152/japplphysiol.00841.2015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 03/21/2016] [Indexed: 11/22/2022] Open
Abstract
Alterations in cerebral hemodynamics in microgravity are hypothesized to occur during spaceflight and could be linked to the Visual Impairment and Intracranial Pressure syndrome. Head-down tilt (HDT) is frequently used as a ground-based analog to simulate cephalad fluid shifts in microgravity; however, its effects on cerebral hemodynamics have not been well studied with MRI techniques. Here, we evaluate the effects of 1) various HDT angles on cerebral arterial and venous hemodynamics; and 2) exposure to 1% CO2 during an intermediate HDT angle (-12°) as an additional space-related environmental factor. Blood flow, cross-sectional area (CSA), and blood flow velocity were measured with phase-contrast MRI in the internal jugular veins, as well as the vertebral and internal carotid arteries. Nine healthy male subjects were measured at baseline (supine, 0°) and after 4.5 h of HDT at -6°, -12° (with and without 1% CO2), and -18°. We found a decrease in total arterial blood flow from baseline during all angles of HDT. On the venous side, CSA increased with HDT, and outflow decreased during -12° HDT (P = 0.039). Moreover, the addition of 1% CO2 to -12° HDT caused an increase in total arterial blood flow (P = 0.016) and jugular venous outflow (P < 0.001) compared with -12° HDT with ambient atmosphere. Overall, the results indicate decreased cerebral blood flow during HDT, which may have implications for microgravity-induced cerebral hemodynamic changes.
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Affiliation(s)
- Karina Marshall-Goebel
- Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany; Faculty of Medicine, University of Cologne, Cologne, Germany;
| | - Khalid Ambarki
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden; Centre of Biomedical Engineering and Physics, Umeå University, Umeå, Sweden
| | - Jan Malm
- Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden
| | - Edwin Mulder
- Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
| | - Darius Gerlach
- Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
| | - Eric Bershad
- Department of Neurology, Baylor College of Medicine, Houston, Texas; and
| | - Jörn Rittweger
- Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany; Department of Pediatric and Adolescent Medicine, University of Cologne, Cologne, Germany
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27
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Johansson E, Ambarki K, Birgander R, Bahrami N, Eklund A, Malm J. Cerebral microbleeds in idiopathic normal pressure hydrocephalus. Fluids Barriers CNS 2016; 13:4. [PMID: 26860218 PMCID: PMC4748449 DOI: 10.1186/s12987-016-0028-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 02/03/2016] [Indexed: 11/25/2022] Open
Abstract
Background A vascular disease could be involved in pathophysiology of normal pressure hydrocephalus (INPH). If so, there should be an association between INPH and cerebral microbleeds (CMB). This study aims to analyze if CMB are associated with INPH. Methods In this case-control study we included 14 patients with INPH (mean age 76 years, 60 % female) and 41 healthy controls (HeCo; mean age 71 years, 60 % female). All were investigated with magnetic resonance imaging (MRI) using a T2*-sequence. The MRI exams were reviewed by two neuroradiologists for the presence of CMBs; the prevalence of findings of two or more CMBs was compared between INPH group and control group. After investigation, INPH patients underwent shunt surgery. Results Two or more CMB were detected more frequently in the INPH group compared to HeCo (n = 6, 43 % vs. n = 4, 10 %; p = 0.01). Among the participants where MRI revealed CMB, the number of CMB was higher among the INPH patients than the HeCo (median 8; IQR 2-34 vs. median 1; IQR 1–2; p = 0.005). Conclusions This study supports a vascular component to the pathophysiology of INPH.
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Affiliation(s)
- Elias Johansson
- Department of Pharmacology and Clinical Neuroscience, Norrlands Universitetssjukhus, Umeå University, S-901 85, Umeå, Sweden.
| | - Khalid Ambarki
- Department of Radiation Sciences, Umeå University, Umeå, Sweden. .,Centre for Biomedical Engineering and Physics, Umeå University, Umeå, Sweden.
| | | | - Nazila Bahrami
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden. .,Centre for Biomedical Engineering and Physics, Umeå University, Umeå, Sweden.
| | - Jan Malm
- Department of Pharmacology and Clinical Neuroscience, Norrlands Universitetssjukhus, Umeå University, S-901 85, Umeå, Sweden.
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28
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Dunås T, Wåhlin A, Ambarki K, Zarrinkoob L, Birgander R, Malm J, Eklund A. Automatic labeling of cerebral arteries in magnetic resonance angiography. MAGMA 2015; 29:39-47. [PMID: 26646523 DOI: 10.1007/s10334-015-0512-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [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: 08/18/2015] [Revised: 11/04/2015] [Accepted: 11/10/2015] [Indexed: 12/25/2022]
Abstract
OBJECTIVES In order to introduce 4D flow magnetic resonance imaging (MRI) as a standard clinical instrument for studying the cerebrovascular system, new and faster postprocessing tools are necessary. The objective of this study was to construct and evaluate a method for automatic identification of individual cerebral arteries in a 4D flow MRI angiogram. MATERIALS AND METHODS Forty-six elderly individuals were investigated with 4D flow MRI. Fourteen main cerebral arteries were manually labeled and used to create a probabilistic atlas. An automatic atlas-based artery identification method (AAIM) was developed based on vascular-branch extraction and the atlas was used for identification. The method was evaluated by comparing automatic with manual identification in 4D flow MRI angiograms from 67 additional elderly individuals. RESULTS Overall accuracy was 93%, and internal carotid artery and middle cerebral artery labeling was 100% accurate. Smaller and more distal arteries had lower accuracy; for posterior communicating arteries and vertebral arteries, accuracy was 70 and 89%, respectively. CONCLUSION The AAIM enabled fast and fully automatic labeling of the main cerebral arteries. AAIM functionality provides the basis for creating an automatic and powerful method to analyze arterial cerebral blood flow in clinical routine.
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Affiliation(s)
- Tora Dunås
- Department of Radiation Sciences, Umeå University, S-901 87, Umeå, Sweden.
| | - Anders Wåhlin
- Department of Radiation Sciences, Umeå University, S-901 87, Umeå, Sweden
- Umeå Center for Functional Brain Imaging, Umeå University, S-901 87, Umeå, Sweden
| | - Khalid Ambarki
- Department of Radiation Sciences, Umeå University, S-901 87, Umeå, Sweden
- Centre for Biomedical Engineering and Physics, Umeå University, S-901 87, Umeå, Sweden
| | - Laleh Zarrinkoob
- Department of Clinical Neuroscience, Umeå University, S-901 87, Umeå, Sweden
| | - Richard Birgander
- Department of Radiation Sciences, Umeå University, S-901 87, Umeå, Sweden
| | - Jan Malm
- Department of Clinical Neuroscience, Umeå University, S-901 87, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, S-901 87, Umeå, Sweden
- Umeå Center for Functional Brain Imaging, Umeå University, S-901 87, Umeå, Sweden
- Centre for Biomedical Engineering and Physics, Umeå University, S-901 87, Umeå, Sweden
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Ambarki K, Wåhlin A, Zarrinkoob L, Wirestam R, Petr J, Malm J, Eklund A. Accuracy of Parenchymal Cerebral Blood Flow Measurements Using Pseudocontinuous Arterial Spin-Labeling in Healthy Volunteers. AJNR Am J Neuroradiol 2015; 36:1816-21. [PMID: 26251434 DOI: 10.3174/ajnr.a4367] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 02/16/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The arterial spin-labeling method for CBF assessment is widely available, but its accuracy is not fully established. We investigated the accuracy of a whole-brain arterial spin-labeling technique for assessing the mean parenchymal CBF and the effect of aging in healthy volunteers. Phase-contrast MR imaging was used as the reference method. MATERIALS AND METHODS Ninety-two healthy volunteers were included: 49 young (age range, 20-30 years) and 43 elderly (age range, 65-80 years). Arterial spin-labeling parenchymal CBF values were averaged over the whole brain to quantify the mean pCBF(ASL) value. Total CBF was assessed with phase-contrast MR imaging as the sum of flows in the internal carotid and vertebral arteries, and subsequent division by brain volume returned the pCBF(PCMRI) value. Accuracy was considered as good as that of the reference method if the systematic difference was less than 5 mL/min/100 g of brain tissue and if the 95% confidence intervals were equal to or better than ±10 mL/min/100 g. RESULTS pCBF(ASL) correlated to pCBF(PCMRI) (r = 0.73; P < .001). Significant differences were observed between the pCBF(ASL) and pCBF(PCMRI) values in the young (P = .001) and the elderly (P < .001) volunteers. The systematic differences (mean ± 2 standard deviations) were -4 ± 14 mL/min/100 g in the young subjects and 6 ± 12 mL/min/100 g in the elderly subjects. Young subjects showed higher values than the elderly subjects for pCBF(PCMRI) (young, 57 ± 8 mL/min/100 g; elderly, 54 ± 7 mL/min/100 g; P = .05) and pCBF(ASL) (young, 61 ± 10 mL/min/100 g; elderly, 48 ± 10 mL/min/100 g; P < .001). CONCLUSIONS The limits of agreement were too wide for the arterial spin-labeling method to be considered satisfactorily accurate, whereas the systematic overestimation in the young subjects and underestimation in the elderly subjects were close to acceptable. The age-related decrease in parenchymal CBF was augmented in arterial spin-labeling compared with phase-contrast MR imaging.
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Affiliation(s)
- K Ambarki
- From the Department of Radiation Sciences (K.A., A.W., A.E.) Centre for Biomedical Engineering and Physics (K.A., A.E.)
| | - A Wåhlin
- From the Department of Radiation Sciences (K.A., A.W., A.E.) Center for Functional Brain Imaging (A.W., A.E.)
| | - L Zarrinkoob
- Department of Clinical Neuroscience (L.Z., J.M.), Umeå University, Umeå, Sweden
| | - R Wirestam
- Department of Medical Radiation Physics (R.W.), Lund University, Lund, Sweden
| | - J Petr
- PET Center (J.P.), Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - J Malm
- Department of Clinical Neuroscience (L.Z., J.M.), Umeå University, Umeå, Sweden
| | - A Eklund
- From the Department of Radiation Sciences (K.A., A.W., A.E.) Centre for Biomedical Engineering and Physics (K.A., A.E.) Center for Functional Brain Imaging (A.W., A.E.)
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Jóhannesson G, Hallberg P, Ambarki K, Eklund A, Lindén C. Age-dependency of ocular parameters: a cross sectional study of young and elderly healthy subjects. Graefes Arch Clin Exp Ophthalmol 2015; 253:1979-83. [DOI: 10.1007/s00417-015-3129-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 06/28/2015] [Accepted: 07/28/2015] [Indexed: 10/23/2022] Open
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Schrauben E, Wåhlin A, Ambarki K, Spaak E, Malm J, Wieben O, Eklund A. Fast 4D flow MRI intracranial segmentation and quantification in tortuous arteries. J Magn Reson Imaging 2015; 42:1458-64. [PMID: 25847621 DOI: 10.1002/jmri.24900] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [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: 01/04/2015] [Accepted: 03/13/2015] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To describe, validate, and implement a centerline processing scheme (CPS) for semiautomated segmentation and quantification in carotid siphons of healthy subjects. 4D flow MRI enables blood flow measurement in all major cerebral arteries with one scan. Clinical translational hurdles are time demanding postprocessing and user-dependence induced variability during analysis. MATERIALS AND METHODS A CPS for 4D flow data was developed to automatically separate cerebral artery trees. Flow parameters were quantified at planes along the centerline oriented perpendicular to the vessel path. At 3T, validation against 2D phase-contrast (PC) magnetic resonance imaging (MRI) and 4D flow manual processing was performed on an intracranial flow phantom for constant flow, while pulsatile flow validation was performed in the internal carotid artery (ICA) of 10 healthy volunteers. The CPS and 4D manual processing times were measured and compared. Flow and area measurements were also demonstrated along the length of the ICA siphon. RESULTS Phantom measurements for area and flow were highly correlated between the CPS and 2D measurements (area: R = 0.95, flow: R = 0.94), while in vivo waveforms were highly correlated (R = 0.93). Processing time was reduced by a factor of 4.6 compared with manual processing. Whole ICA measurements revealed a significantly decreased area in the most distal segment of the carotid siphon (P = 0.0017), with flow unchanged (P = 0.84). CONCLUSION This study exhibits fast semiautomated analysis of intracranial 4D flow MRI. Internal consistency was shown through flow conservation along the tortuous ICA siphon, which is typically difficult to assess.
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Affiliation(s)
- Eric Schrauben
- Department of Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, USA.,Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Anders Wåhlin
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.,Umeå Center for Functional Brain Imaging (UFBI), Umeå University, Umeå, Sweden.,Department of Radiology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Khalid Ambarki
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.,Center for Biomedical Engineering and Physics, Umeå University, Umeå, Sweden
| | - Erik Spaak
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Jan Malm
- Department of Clinical Neuroscience, Umeå University, Umeå, Sweden
| | - Oliver Wieben
- Department of Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, USA.,Department of Radiology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.,Center for Biomedical Engineering and Physics, Umeå University, Umeå, Sweden
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Wåhlin A, Ambarki K, Birgander R, Malm J, Eklund A. Intracranial pulsatility is associated with regional brain volume in elderly individuals. Neurobiol Aging 2013; 35:365-72. [PMID: 24080175 DOI: 10.1016/j.neurobiolaging.2013.08.026] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [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: 04/24/2013] [Revised: 08/16/2013] [Accepted: 08/23/2013] [Indexed: 10/26/2022]
Abstract
Excessive intracranial pulsatility is thought to damage the cerebral microcirculation, causing cognitive decline in elderly individuals. We investigated relationships between brain structure and measures related to intracranial pulsatility among healthy elderly. Thirty-seven stroke-free, non-demented individuals (62-82 years of age) were included. We assessed brain structure, invasively measured cerebrospinal fluid (CSF) pulse pressure, and magnetic resonance-quantified arterial and CSF flow pulsatility, as well as arterial pulse pressure. Using both multivariate partial least squares and ordinary regression analyses, we identified a significant pattern of negative relationships between the volume of several brain regions and measures of intracranial pulsatility. The strongest relationships concerned the temporal lobe cortex and hippocampus. These findings were also coherent with observations of positive relationships between intracranial pulsatility and ventricular volume. In conclusion, elderly subjects with high intracranial pulsatility display smaller brain volume and larger ventricles, supporting the notion that excessive cerebral arterial pulsatility harms the brain. This calls for research investigating altered intracranial cardiac-related pulsatile stress as a potential risk factor that may cause or worsen the prognosis in subjects developing cognitive impairment and dementia.
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Affiliation(s)
- Anders Wåhlin
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.
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Wåhlin A, Ambarki K, Birgander R, Wieben O, Johnson KM, Malm J, Eklund A. Measuring pulsatile flow in cerebral arteries using 4D phase-contrast MR imaging. AJNR Am J Neuroradiol 2013; 34:1740-5. [PMID: 23493888 DOI: 10.3174/ajnr.a3442] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE 4D PCMRI can be used to quantify pulsatile hemodynamics in multiple cerebral arteries. The aim of this study was to compare 4D PCMRI and 2D PCMRI for assessments of pulsatile hemodynamics in major cerebral arteries. MATERIALS AND METHODS We scanned the internal carotid artery, the anterior cerebral artery, the basilar artery, and the middle cerebral artery in 10 subjects with a single 4D and multiple 2D PCMRI acquisitions by use of a 3T system and a 32-channel head coil. We assessed the agreement regarding net flow and the volume of arterial pulsatility (ΔV) for all vessels. RESULTS 2D and 4D PCMRI produced highly correlated results, with r = 0.86 and r = 0.95 for ΔV and net flow, respectively (n = 69 vessels). These values increased to r = 0.93 and r = 0.97, respectively, during investigation of a subset of measurements with <5% variation in heart rate between the 4D and 2D acquisition (n = 31 vessels). Significant differences were found for ICA and MCA net flow (P = .004 and P < .001, respectively) and MCA ΔV (P = .006). However, these differences were attenuated and no longer significant when the subset with stable heart rate (n = 31 vessels) was analyzed. CONCLUSIONS 4D PCMRI provides a powerful methodology to measure pulsatility of the larger cerebral arteries from a single acquisition. A large part of differences between measurements was attributed to physiologic variations. The results were consistent with 2D PCMRI.
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Affiliation(s)
- A Wåhlin
- Department of Radiation Sciences
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Ambarki K, Israelsson H, Wåhlin A, Birgander R, Eklund A, Malm J. Brain ventricular size in healthy elderly: comparison between Evans index and volume measurement. Neurosurgery 2013; 67:94-9; discussion 99. [PMID: 20559096 DOI: 10.1227/01.neu.0000370939.30003.d1] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND A precise definition of ventricular enlargement is important in the diagnosis of hydrocephalus as well as in assessing central atrophy. The Evans index (EI), a linear ratio between the maximal frontal horn width and the cranium diameter, has been extensively used as an indirect marker of ventricular volume (VV). With modern imaging techniques, brain volume can be directly measured. OBJECTIVE To determine reference values of intracranial volumes in healthy elderly individuals and to correlate volumes with the EI. METHODS Magnetic resonance imaging (3 T) was performed in 46 healthy white elderly subjects (mean age+/-standard deviation, 71+/-6 years) and in 20 patients (74+/-7 years) with large ventricles according to visual inspection. VV, relative VV (RVV), and EI were assessed. Ventricular dilation was defined using VV and EI by a value above the 95th percentile range for healthy elderly individuals. RESULTS In healthy elderly subjects, we found VV=37+/-18 mL, RVV=2.47+/-1.17%, and EI=0.281+/-0.027. Including the patients, there was a strong correlation between EI and VV (R=0.94) as well as between EI and RVV (R=0.95). However, because of a wide 95% prediction interval (VV: +/-45 mL; RVV: +/-2.54%), EI did not give a sufficiently good estimate of VV and RVV. CONCLUSION VV (or RVV) and the EI reflect different properties. The exclusive use of EI in clinical studies as a marker of enlarged ventricles should be questioned. We suggest that the definition of dilated ventricles in white elderly individuals be defined as VV>77 mL or RVV>4.96 %. Future studies should compare intracranial volumes with clinical characteristics and prognosis.
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Affiliation(s)
- Khalid Ambarki
- Department of Biomedical Engineering, Umeå University, Umeå, Sweden.
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Ambarki K, Hallberg P, Jóhannesson G, Lindén C, Zarrinkoob L, Wåhlin A, Birgander R, Malm J, Eklund A. Blood flow of ophthalmic artery in healthy individuals determined by phase-contrast magnetic resonance imaging. Invest Ophthalmol Vis Sci 2013; 54:2738-45. [PMID: 23518769 DOI: 10.1167/iovs.13-11737] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Recent development of magnetic resonance imaging (MRI) offers new possibilities to assess ocular blood flow. This prospective study evaluates the feasibility of phase-contrast MRI (PCMRI) to measure flow rate in the ophthalmic artery (OA) and establish reference values in healthy young (HY) and elderly (HE) subjects. METHODS Fifty HY subjects (28 females, 21-30 years of age) and 44 HE (23 females, 64-80 years of age) were scanned on a 3-Tesla MR system. The PCMRI sequence had a spatial resolution of 0.35 mm per pixel, with the measurement plan placed perpendicularly to the OA. Mean flow rate (Qmean), resistive index (RI), and arterial volume pulsatility of OA (ΔVmax) were measured from the flow rate curve. Accuracy of PCMRI measures was investigated using a vessel-phantom mimicking the diameter and the flow rate range of the human OA. RESULTS Flow rate could be assessed in 97% of the OAs. Phantom investigations showed good agreement between the reference and PCMRI measurements with an error of <7%. No statistical difference was found in Qmean between HY and HE individuals (HY: mean ± SD = 10.37 ± 4.45 mL/min; HE: 10.81 ± 5.15 mL/min, P = 0.655). The mean of ΔVmax (HY: 18.70 ± 7.24 μL; HE: 26.27 ± 12.59 μL, P < 0.001) and RI (HY: 0.62 ± 0.08; HE: 0.67 ± 0.1, P = 0.012) were significantly different between HY and HE. CONCLUSIONS This study demonstrated that the flow rate of OA can be quantified using PCMRI. There was an age difference in the pulsatility parameters; however, the mean flow rate appeared independent of age. The primary difference in flow curves between HE and HY was in the relaxation phase of the systolic peak.
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Ambarki K, Lindqvist T, Wåhlin A, Petterson E, Warntjes MJB, Birgander R, Malm J, Eklund A. Evaluation of automatic measurement of the intracranial volume based on quantitative MR imaging. AJNR Am J Neuroradiol 2012; 33:1951-6. [PMID: 22555574 DOI: 10.3174/ajnr.a3067] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Brain size is commonly described in relation to ICV, whereby accurate assessment of this quantity is fundamental. Recently, an optimized MR sequence (QRAPMASTER) was developed for simultaneous quantification of T1, T2, and proton density. ICV can be measured automatically within minutes from QRAPMASTER outputs and a dedicated software, SyMRI. Automatic estimations of ICV were evaluated against the manual segmentation. MATERIALS AND METHODS In 19 healthy subjects, manual segmentation of ICV was performed by 2 neuroradiologists (Obs1, Obs2) by using QBrain software and conventional T2-weighted images. The automatic segmentation from the QRAPMASTER output was performed by using SyMRI. Manual corrections of the automatic segmentation were performed (corrected-automatic) by Obs1 and Obs2, who were blinded from each other. Finally, the repeatability of the automatic method was evaluated in 6 additional healthy subjects, each having 6 repeated QRAPMASTER scans. The time required to measure ICV was recorded. RESULTS No significant difference was found between reference and automatic (and corrected-automatic) ICV (P > .25). The mean difference between the reference and automatic measurement was -4.84 ± 19.57 mL (or 0.31 ± 1.35%). Mean differences between the reference and the corrected-automatic measurements were -0.47 ± 17.95 mL (-0.01 ± 1.24%) and -1.26 ± 17.68 mL (-0.06 ± 1.22%) for Obs1 and Obs2, respectively. The repeatability errors of the automatic and the corrected-automatic method were <1%. The automatic method required 1 minute 11 seconds (SD = 12 seconds) of processing. Adding manual corrections required another 1 minute 32 seconds (SD = 38 seconds). CONCLUSIONS Automatic and corrected-automatic quantification of ICV showed good agreement with the reference method. SyMRI software provided a fast and reproducible measure of ICV.
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Affiliation(s)
- K Ambarki
- Department of Radiation Science, Umeå University, Umeå, Sweden.
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Vågberg M, Lindqvist T, Ambarki K, Warntjes JBM, Sundström P, Birgander R, Svenningsson A. Automated determination of brain parenchymal fraction in multiple sclerosis. AJNR Am J Neuroradiol 2012; 34:498-504. [PMID: 22976234 DOI: 10.3174/ajnr.a3262] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND AND PURPOSE Brain atrophy is a manifestation of tissue damage in MS. Reduction in brain parenchymal fraction is an accepted marker of brain atrophy. In this study, the approach of synthetic tissue mapping was applied, in which brain parenchymal fraction was automatically calculated based on absolute quantification of the tissue relaxation rates R1 and R2 and the proton attenuation. MATERIALS AND METHODS The BPF values of 99 patients with MS and 35 control subjects were determined by using SyMap and tested in relationship to clinical variables. A subset of 5 patients with MS and 5 control subjects were also analyzed with a manual segmentation technique as a reference. Reproducibility of SyMap was assessed in a separate group of 6 healthy subjects, each scanned 6 consecutive times. RESULTS Patients with MS had significantly lower BPF (0.852 ± 0.0041, mean ± SE) compared with control subjects (0.890 ± 0.0040). Significant linear relationships between BPF and age, disease duration, and Expanded Disability Status Scale scores were observed (P < .001). A strong correlation existed between SyMap and the reference method (r = 0.96; P < .001) with no significant difference in mean BPF. Coefficient of variation of repeated SyMap BPF measurements was 0.45%. Scan time was <6 minutes, and postprocessing time was <2 minutes. CONCLUSIONS SyMap is a valid and reproducible method for determining BPF in MS within a clinically acceptable scan time and postprocessing time. Results are highly congruent with those described using other methods and show high agreement with the manual reference method.
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Affiliation(s)
- M Vågberg
- Department of Pharmacology and Clinical Neuroscience, Section of Neuroscience, Umeå University, Umeå, Sweden.
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Abstract
OBJECTIVES Dilated ventricles and gait disturbances are common in the elderly, and these are also features of the treatable syndrome idiopathic normal pressure hydrocephalus (INPH). Many studies report an association between hypertension, vascular disease and INPH. The objective of this study was to study the frequency of ventriculomegaly, with or without hydrocephalic symptoms, in patients who had suffered from a transitory ischaemic attack (TIA). METHODS Gait, Romberg sign, tandem standing and one-leg stance were consecutively evaluated in elderly > 24 h after a TIA. Ventricular size, white matter lesions and atrophy were assessed on computed tomography scans. Exclusion criteria were conditions possibly influencing the balance tests. RESULTS eventy-six patients with TIA out of 105 were included. Ventriculomegaly [Evans Index (EI) > 0.30] was observed in 19.7% and very large ventricles (EI > 0.33) in 7.9%. Ventriculomegaly was found in 58% of the patients with a previous 'history of balance or gait disturbance', but only in 12% of those without any prior disturbance (chi-square test; P = 0.0009). Three out of 76 patients with TIA (3.9%) fulfilled both radiological and clinical criteria for 'possible INPH'. CONCLUSION Ventriculomegaly is a common finding in elderly. One out of 20 patients with TIA may suffer from INPH, existing before and independent of the TIA diagnosis. Therefore, patients presenting with ventriculomegaly and gait/balance disturbances not attributable to other causes should be referred to a hydrocephalus centre or a neurologist with special interest in INPH.
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Affiliation(s)
- H Israelsson
- Department of Clinical Neuroscience, Umeå University, Sweden.
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Wåhlin A, Ambarki K, Hauksson J, Birgander R, Malm J, Eklund A. Phase contrast MRI quantification of pulsatile volumes of brain arteries, veins, and cerebrospinal fluids compartments: repeatability and physiological interactions. J Magn Reson Imaging 2011; 35:1055-62. [PMID: 22170792 DOI: 10.1002/jmri.23527] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Accepted: 11/08/2011] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To study measurement repeatability and physiological determinants on measurement stability for phase contrast MRI (PC-MRI) measurements of cyclic volume changes (ΔV) of brain arteries, veins, and cerebrospinal fluid (CSF) compartments. MATERIALS AND METHODS Total cerebral blood flow (tCBF), total internal jugular flow (tJBF) and spinal CSF flow at C2-C3 level and CSF in the aqueduct was measured using five repetitions in 20 healthy subjects. After subtracting net flow, waveforms were integrated to calculate ΔV of arterial, venous, and cerebrospinal fluid compartments. The intraclass correlation coefficient (ICC) was used to measure repeatability. Systematic errors were investigated by a series of phantom measurements. RESULTS For ΔV calculated from tCBF, tJBF and both CSF waveforms, the ICC was ≥0.85. ΔV from the tCBF waveform decreased linearly between repetitions (P = 0.012). Summed CSF and venous volume being shifted out from the cranium was correlated with ΔV calculated from the tCBF waveform (r = 0.75; P < 0.001). Systematic errors increased at resolutions <4 pixels per diameter. CONCLUSION Repeatability of ΔV calculated from tCBF, tJBF, and CSF waveforms allows useful interpretations. The subject's time in the MR system and imaging resolution should be considered when interpreting volume changes. Summed CSF and venous volume changes was associated with arterial volume changes.
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Affiliation(s)
- Anders Wåhlin
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.
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Behrens A, Lenfeldt N, Ambarki K, Malm J, Eklund A, Koskinen LO. Intracranial Pressure and Pulsatility Index. Neurosurgery 2011; 69:E1033-4; author reply E1034. [DOI: 10.1227/neu.0b013e31822999b7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Sundstrom P, Wahlin A, Ambarki K. Venous and Cerebrospinal Fluid Flow in Multiple Sclerosis: A Case-Control Study. J Vasc Surg 2011. [DOI: 10.1016/j.jvs.2010.12.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Behrens A, Lenfeldt N, Ambarki K, Malm J, Eklund A, Koskinen LO. Transcranial Doppler pulsatility index: not an accurate method to assess intracranial pressure. Neurosurgery 2010; 66:1050-7. [PMID: 20495421 DOI: 10.1227/01.neu.0000369519.35932.f2] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Transcranial Doppler sonography (TCD) assessment of intracranial blood flow velocity has been suggested to accurately determine intracranial pressure (ICP). OBJECTIVE We attempted to validate this method in patients with communicating cerebrospinal fluid systems using predetermined pressure levels. METHODS Ten patients underwent a lumbar infusion test, applying 4 to 5 preset ICP levels. On each level, the pulsatility index (PI) in the middle cerebral artery was determined by measuring the blood flow velocity using TCD. ICP was simultaneously measured with an intraparenchymal sensor. ICP and PI were compared using correlation analysis. For further understanding of the ICP-PI relationship, a mathematical model of the intracranial dynamics was simulated using a computer. RESULTS The ICP-PI regression equation was based on data from 8 patients. For 2 patients, no audible Doppler signal was obtained. The equation was ICP = 23*PI + 14 (R = 0.22, P < .01, N = 35). The 95% confidence interval for a mean ICP of 20 mm Hg was -3.8 to 43.8 mm Hg. Individually, the regression coefficients varied from 42 to 90 and the offsets from -32 to +3. The mathematical simulations suggest that variations in vessel compliance, autoregulation, and arterial pressure have a serious effect on the ICP-PI relationship. CONCLUSIONS The in vivo results show that PI is not a reliable predictor of ICP. Mathematical simulations indicate that this is caused by variations in physiological parameters.
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Affiliation(s)
- Anders Behrens
- Department of Clinical Neuroscience, Umeå University, Umeå, Sweden.
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Behrens A, Lenfeldt N, Ambarki K, Malm J, Eklund A, Koskinen LO. In Reply. Neurosurgery 2010; 67:E1864. [PMID: 27759663 DOI: 10.1227/neu.0b013e3181fdbf39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Abstract
BACKGROUND AND PURPOSE Automatic assessment of brain volumes is needed in research and clinical practice. Manual tracing is still the criterion standard but is time-consuming. It is important to validate the automatic tools to avoid the problems of clinical studies drawing conclusions on the basis of brain volumes estimated with methodologic errors. The objective of this study was to evaluate a new commercially available fully automatic software for MR imaging of brain volume assessment. Automatic and expert manual brain volumes were compared. MATERIALS AND METHODS MR imaging (3T, axial T2 and FLAIR) was performed in 41 healthy elderly volunteers (mean age, 70 ± 6 years) and 20 patients with hydrocephalus (mean age, 73 ± 7 years). The software Q(Brain) was used to manually and automatically measure the following brain volumes: ICV, BTV, VV, and WMHV. The manual method has been previously validated and was used as the reference. Agreement between the manual and automatic methods was evaluated by using linear regression and Bland-Altman plots. RESULTS There were significant differences between the automatic and manual methods regarding all volumes. The mean differences were ICV = 49 ± 93 mL (mean ± 2SD, n = 61), BTV = 11 ± 70 mL, VV = -6 ± 10 mL, and WMHV = 2.4 ± 9 mL. The automatic calculations of brain volumes took approximately 2 minutes per investigation. CONCLUSIONS The automatic tool is promising and provides rapid assessment of brain volumes. However, the software needs improvement before it is incorporated into research or daily use. Manual segmentation remains the reference method.
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Affiliation(s)
- K Ambarki
- Department of Biomedical Engineering and Informatics, Umeå University, Sweden.
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Sundström P, Wåhlin A, Ambarki K, Birgander R, Eklund A, Malm J. Venous and cerebrospinal fluid flow in multiple sclerosis: a case-control study. Ann Neurol 2010; 68:255-9. [PMID: 20695018 DOI: 10.1002/ana.22132] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The prevailing view on multiple sclerosis etiopathogenesis has been challenged by the suggested new entity chronic cerebrospinal venous insufficiency. To test this hypothesis, we studied 21 relapsing-remitting multiple sclerosis cases and 20 healthy controls with phase-contrast magnetic resonance imaging. In addition, in multiple sclerosis cases we performed contrast-enhanced magnetic resonance angiography. We found no differences regarding internal jugular venous outflow, aqueductal cerebrospinal fluid flow, or the presence of internal jugular blood reflux. Three of 21 cases had internal jugular vein stenoses. In conclusion, we found no evidence confirming the suggested vascular multiple sclerosis hypothesis.
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Affiliation(s)
- Peter Sundström
- Department of Clinical Neuroscience, Umeå University, Sweden
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Abstract
BACKGROUND AND PURPOSE The PVI(CC) of the craniospinal compartment defines the shape of the pressure-volume curve and determines the damping of cyclic arterial pulsations. Despite no reports of direct measurements of the PVI(CC) among healthy elderly, it is believed that a change away from adequate accommodation of cardiac-related pulsations may be a pathophysiologic mechanism seen in neurodegenerative disorders such as Alzheimer disease and idiopathic normal pressure hydrocephalus. In this study, blood and CSF flow measurements are combined with lumbar CSF infusion measurements to assess the craniospinal PVI(CC) and its distribution of cranial and spinal compartments in healthy elderly. MATERIALS AND METHODS Thirty-seven healthy elderly were included (60-82 years of age). The cyclic arterial volume change and the resulting shift of CSF to the spinal compartment were quantified by PC-MR imaging. In addition, each subject underwent a lumbar CSF infusion test in which the magnitude of cardiac-related pulsations in intracranial pressure was quantified. Finally, the PVI was calculated by using a mathematic model. RESULTS After excluding 2 extreme values, the craniospinal PVI(CC) was calculated to a mean of 9.8 ± 2.7 mL and the estimated average 95% confidence interval of individual measurements was ± 9%. The average intracranial and spinal contributions to the overall compliance were 65% and 35% respectively (n = 35). CONCLUSIONS Combining lumbar CSF infusion and PC-MR imaging proved feasible and robust for assessment of the craniospinal PVI(CC). This study produced normative values and showed that the major compensatory contribution was located intracranially.
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Affiliation(s)
- A Wåhlin
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.
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Ambarki K, Birgander R, Wåhlin A, Eklund A, Malm J. O.017 Ventricular size in healthy elderly and idiopathic normal pressure hydrocephalus: Should we use Evans index? Clin Neurol Neurosurg 2008. [DOI: 10.1016/s0303-8467(08)70022-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Wåhlin A, Ambarki K, Birgander R, Malm J, Eklund A. O.009 Volume changes inside the craniospinal system during the cardiac cycle. Clin Neurol Neurosurg 2008. [DOI: 10.1016/s0303-8467(08)70014-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Wåhlin A, Ambarki K, Garpebring A, Hauksson J, Birgander R, Malm J, Eklund A. O.020 Can we measure blood and CSF flows adequately using phase contrast MRI? Clin Neurol Neurosurg 2008. [DOI: 10.1016/s0303-8467(08)70025-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ambarki K, Baledent O, Kongolo G, Bouzerar R, Fall S, Meyer ME. A new lumped-parameter model of cerebrospinal hydrodynamics during the cardiac cycle in healthy volunteers. IEEE Trans Biomed Eng 2007; 54:483-91. [PMID: 17355060 DOI: 10.1109/tbme.2006.890492] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Our knowledge of cerebrospinal fluid (CSF) hydrodynamics has been considerably improved with the recent introduction of phase-contrast magnetic resonance imaging (phase-contrast MRI), which can provide CSF and blood flow measurements throughout the cardiac cycle. Key temporal and amplitude parameters can be calculated at different sites to elucidate the role played by the various CSF compartments during vascular brain expansion. Most of the models reported in the literature do not take into account CSF oscillation during the cardiac cycle and its kinetic energy impact on the brain. We propose a new lumped-parameter compartmental model of CSF and blood flows in healthy subjects during the cardiac cycle. The system was divided into five submodels representing arterial blood, venous blood, ventricular CSF, cranial subarachnoid space, and spinal subarachnoid space. These submodels are connected by resistances and compliances. The model developed was used to reproduce certain functional characteristics observed in seven healthy volunteers, such as the distribution (amplitude and phase shift) of arterial, venous, and CSF flows. The results show a good agreement between measured and simulated intracranial CSF and blood flows.
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Affiliation(s)
- Khalid Ambarki
- Department of Imaging and Biophysics, Teaching Hospitals, Jules Verne University of Picardie, Amiens 80054, France.
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