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Comparison of magnetic resonance angiography techniques to brain digital subtraction arteriography in the setting of mechanical thrombectomy: A non-inferiority study. Rev Neurol (Paris) 2022; 178:539-545. [DOI: 10.1016/j.neurol.2021.12.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 12/01/2021] [Accepted: 12/06/2021] [Indexed: 11/23/2022]
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Bo T, Kawana Y, Soejima I, Amano E, Komatsuzaki T, Oyama J, Machida A. Pulse-gated noncontrast thoracic magnetic resonance angiography for acute aortic dissection with transient ischemic attack: A case report. eNeurologicalSci 2021; 23:100329. [PMID: 33681485 PMCID: PMC7910496 DOI: 10.1016/j.ensci.2021.100329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/03/2021] [Accepted: 02/18/2021] [Indexed: 11/30/2022] Open
Abstract
Aortic dissection is a rare cause of an acute ischemic stroke or transient ischemic attack (TIA). Aortic dissection is particularly challenging in stroke patients who are eligible for thrombolysis secondary to the diagnostic difficulty within a narrow time window (4.5 h) and have a risk of developing life-threatening hemorrhagic complications following thrombolysis. Computed tomographic angiography (CTA) has been the mainstay of imaging when evaluating acute aortic syndrome. However, it cannot be routinely performed for pregnant patients and those with renal failure or iodine-contrast media allergy. We report a case of a 72-year-old woman who developed transient right-hand paralysis without any chest symptoms. Brain magnetic resonance imaging (MRI) showed no recent infarction; however, the brachiocephalic trunk was not well visualized on carotid magnetic resonance angiography (MRA). Subsequent thoracic pulse-gated noncontrast three-dimensional balanced steady-state free precession MRA (bSSFP-MRA) detected a Stanford type A acute aortic dissection (TAAAD). This was confirmed by CTA, leading to the diagnosis of TIA due to Stanford TAAAD. Pulse-gated noncontrast thoracic bSSFP-MRA was acquired a few minutes after a series of brain MRI scans. This imaging modality is expected to be used as a screening platform to rule out Stanford TAAAD during the hyperacute phase of stroke. CTA has been the mainstay of imaging when evaluating acute aortic syndrome. bSSFP-MRA can detect Stanford type A acute aortic dissection. Pulse-gated noncontrast thoracic bSSFP-MRA can screen for Stanford TAAAD.
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Affiliation(s)
- Takeshi Bo
- Department of Neurology, Tsuchiura Kyodo General Hospital, Japan
| | - Yasuhito Kawana
- Department of Neurology, Tsuchiura Kyodo General Hospital, Japan
| | - Itsuki Soejima
- Department of Neurology, Tsuchiura Kyodo General Hospital, Japan
| | - Eiichiro Amano
- Department of Neurology, Tsuchiura Kyodo General Hospital, Japan
| | | | - Jun Oyama
- Department of Diagnostic Radiology and Nuclear Medicine, Tokyo Medical and Dental University, Japan
| | - Akira Machida
- Department of Neurology, Tsuchiura Kyodo General Hospital, Japan
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Accelerated Time-Resolved Contrast-Enhanced Magnetic Resonance Angiography of Dural Arteriovenous Fistulas Using Highly Constrained Reconstruction of Sparse Cerebrovascular Data Sets. Invest Radiol 2017; 51:365-71. [PMID: 26488372 DOI: 10.1097/rli.0000000000000212] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Time-resolved contrast-enhanced magnetic resonance angiography (MRA) is commonly used to noninvasively characterize vascular malformations. However, the spatial and temporal resolution of current methods often compromises the clinical value of the examinations. Constrained reconstruction is a temporal spatial correlation strategy that exploits the relative sparsity of vessels in space to dramatically reduce the amount of data required to generate fast high-resolution time-resolved contrast-enhanced MRA studies. In this report, we use a novel temporal spatial acceleration method termed HYPRFlow to diagnose and classify dural arteriovenous fistulas (DAVFs). Our hypothesis is that HYPRFlow images are of adequate diagnostic image quality to delineate the arterial and venous components of DAVFs and allow correct classification using the Cognard system. SUBJECTS AND METHODS Eight patients with known DAVFs underwent HYPRFlow imaging with isotropic resolution of 0.68 mm and temporal resolution of 0.75 second and 3-dimensional time-of-flight (3DTOF) MRA. The 3DTOF images and HYPRFlow images were evaluated by 2 readers and scored for arterial anatomic image quality. Digital subtraction angiography (DSA) was available for comparison in 7 subjects, and for these patients, each DAVF was classified according to the Cognard system using HYPRFlow and DSA examinations. Digital subtraction angiography was considered the reference examination or criterion standard. RESULTS HYPRFlow imaging classification was concordant with DSA in all but 1 case. There was no difference in the arterial image quality scores between HYPRFlow and 3DTOF MRA (95% confidence interval). Arterial-to-venous separation was rated excellent (n = 3), good (n = 4), or poor (n = 1), and arteriovenous shunting was easily appreciated. Undersampling artifacts were reduced by using a low pass filter and did not interfere with the diagnostic quality of the examinations. CONCLUSIONS HYPRFlow is a novel acquisition and reconstruction technique that exploits the relative sparsity of intracranial vessels in space to increase temporal and spatial resolution and provides accurate delineation of DAVF vasculature.
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Laviña B. Brain Vascular Imaging Techniques. Int J Mol Sci 2016; 18:ijms18010070. [PMID: 28042833 PMCID: PMC5297705 DOI: 10.3390/ijms18010070] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/13/2016] [Accepted: 12/26/2016] [Indexed: 12/13/2022] Open
Abstract
Recent major improvements in a number of imaging techniques now allow for the study of the brain in ways that could not be considered previously. Researchers today have well-developed tools to specifically examine the dynamic nature of the blood vessels in the brain during development and adulthood; as well as to observe the vascular responses in disease situations in vivo. This review offers a concise summary and brief historical reference of different imaging techniques and how these tools can be applied to study the brain vasculature and the blood-brain barrier integrity in both healthy and disease states. Moreover, it offers an overview on available transgenic animal models to study vascular biology and a description of useful online brain atlases.
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Affiliation(s)
- Bàrbara Laviña
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, 75185 Uppsala, Sweden.
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Al-Jehani H, Yamani M, Orz Y, Shiekh B. Familial Intracranial Aneurysms in Saudi Arabia: What Do We Need To Do? SAUDI JOURNAL OF MEDICINE & MEDICAL SCIENCES 2016; 4:149-153. [PMID: 30787721 PMCID: PMC6298339 DOI: 10.4103/1658-631x.188252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Aneurysmal subarachnoid hemorrhage (SAH) is a devastating event with significant morbidity and mortality. The incidence of SAH might be influenced by environmental factors but genetic predisposition is evolving as an important effector in the risk of development of intracranial aneurysms and rupture of aneurysms. This requires strategies for effective screening of family members at risk of developing such a phenotype, in order to deliver preventive treatment to these target lesions. We discuss the potential for implementing these strategies in the Saudi Arabian health system and the future implications on our care for such a vulnerable group of subjects.
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Affiliation(s)
- Hosam Al-Jehani
- Department of Neurosurgery, King Fahd University Hospital, University of Dammam, Al-Khobar, Saudi Arabia.,Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University Health Centre, Montreal, Canada
| | - Mahmoud Yamani
- Department of Neurosurgery, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Yasser Orz
- Department of Neurosurgery, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Bassem Shiekh
- Department of Surgery, Taibah University, Al-Madina Al-Monawrrah, Saudi Arabia
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Balaji R. Time-resolved MR angiography in wake-up stroke: an innovative application of a proven technique. Acad Radiol 2015; 22:411-2. [PMID: 25753592 DOI: 10.1016/j.acra.2015.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 01/22/2015] [Accepted: 01/22/2015] [Indexed: 10/23/2022]
Affiliation(s)
- Ravikanth Balaji
- Department Of Radiology, Apollo Specialty Hospital, #320, Padma Towers, Mount Road, CHENNAI, Tamil Nadu 600035, INDIA.
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Le Bras A, Raoult H, Ferré JC, Ronzière T, Gauvrit JY. Optimal MRI sequence for identifying occlusion location in acute stroke: which value of time-resolved contrast-enhanced MRA? AJNR Am J Neuroradiol 2015; 36:1081-8. [PMID: 25767186 DOI: 10.3174/ajnr.a4264] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 12/21/2014] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Identifying occlusion location is crucial for determining the optimal therapeutic strategy during the acute phase of ischemic stroke. The purpose of this study was to assess the diagnostic efficacy of MR imaging, including conventional sequences plus time-resolved contrast-enhanced MRA in comparison with DSA for identifying arterial occlusion location. MATERIALS AND METHODS Thirty-two patients with 34 occlusion levels referred for thrombectomy during acute cerebral stroke events were consecutively included from August 2010 to December 2012. Before thrombectomy, we performed 3T MR imaging, including conventional 3D-TOF and gradient-echo T2 sequences, along with time-resolved contrast-enhanced MRA of the extra- and intracranial arteries. The 3D-TOF, gradient-echo T2, and time-resolved contrast-enhanced MRA results were consensually assessed by 2 neuroradiologists and compared with prethrombectomy DSA results in terms of occlusion location. The Wilcoxon test was used for statistical analysis to compare MR imaging sequences with DSA, and the κ coefficient was used to determine intermodality agreement. RESULTS The occlusion level on the 3D-TOF and gradient-echo T2 images differed significantly from that of DSA (P < .001 and P = .002, respectively), while no significant difference was observed between DSA and time-resolved contrast-enhanced MRA (P = .125). κ coefficients for intermodality agreement with DSA (95% CI, percentage agreement) were 0.43 (0.3%-0.6; 62%), 0.32 (0.2%-0.5; 56%), and 0.81 (0.6%-1.0; 88%) for 3D-TOF, gradient-echo T2, and time-resolved contrast-enhanced MRA, respectively. CONCLUSIONS The time-resolved contrast-enhanced MRA sequence proved reliable for identifying occlusion location in acute stroke with performance superior to that of 3D-TOF and gradient-echo T2 sequences.
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Affiliation(s)
- A Le Bras
- From the Departments of Neuroradiology (A.L.B., H.R., J.-C.F., J.-Y.G.)
| | - H Raoult
- From the Departments of Neuroradiology (A.L.B., H.R., J.-C.F., J.-Y.G.) Unité VISAGE U746 INSERM-INRIA, IRISA UMR CNRS 6074 (H.R., J.-C.F., J.-Y.G.), University of Rennes, Rennes, France
| | - J-C Ferré
- From the Departments of Neuroradiology (A.L.B., H.R., J.-C.F., J.-Y.G.) Unité VISAGE U746 INSERM-INRIA, IRISA UMR CNRS 6074 (H.R., J.-C.F., J.-Y.G.), University of Rennes, Rennes, France
| | - T Ronzière
- Neurology (T.R.), Centre Hospitalier Universitaire Rennes, Rennes, France
| | - J-Y Gauvrit
- From the Departments of Neuroradiology (A.L.B., H.R., J.-C.F., J.-Y.G.) Unité VISAGE U746 INSERM-INRIA, IRISA UMR CNRS 6074 (H.R., J.-C.F., J.-Y.G.), University of Rennes, Rennes, France
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Stalder AF, Schmidt M, Quick HH, Schlamann M, Maderwald S, Schmitt P, Wang Q, Nadar MS, Zenge MO. Highly undersampled contrast-enhanced MRA with iterative reconstruction: Integration in a clinical setting. Magn Reson Med 2014; 74:1652-60. [PMID: 25522299 DOI: 10.1002/mrm.25565] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 10/17/2014] [Accepted: 11/17/2014] [Indexed: 11/06/2022]
Abstract
PURPOSE To integrate, optimize, and evaluate a three-dimensional (3D) contrast-enhanced sparse MRA technique with iterative reconstruction on a standard clinical MR system. METHODS Data were acquired using a highly undersampled Cartesian spiral phyllotaxis sampling pattern and reconstructed directly on the MR system with an iterative SENSE technique. Undersampling, regularization, and number of iterations of the reconstruction were optimized and validated based on phantom experiments and patient data. Sparse MRA of the whole head (field of view: 265 × 232 × 179 mm(3) ) was investigated in 10 patient examinations. RESULTS High-quality images with 30-fold undersampling, resulting in 0.7 mm isotropic resolution within 10 s acquisition, were obtained. After optimization of the regularization factor and of the number of iterations of the reconstruction, it was possible to reconstruct images with excellent quality within six minutes per 3D volume. Initial results of sparse contrast-enhanced MRA (CEMRA) in 10 patients demonstrated high-quality whole-head first-pass MRA for both the arterial and venous contrast phases. CONCLUSION While sparse MRI techniques have not yet reached clinical routine, this study demonstrates the technical feasibility of high-quality sparse CEMRA of the whole head in a clinical setting. Sparse CEMRA has the potential to become a viable alternative where conventional CEMRA is too slow or does not provide sufficient spatial resolution.
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Affiliation(s)
| | | | - Harald H Quick
- Erwin L. Hahn Institute for MR Imaging, University of Duisburg-Essen, Germany.,High Field and Hybrid MR Imaging, University Hospital Essen, Germany
| | - Marc Schlamann
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Germany
| | - Stefan Maderwald
- Erwin L. Hahn Institute for MR Imaging, University of Duisburg-Essen, Germany
| | | | - Qiu Wang
- Siemens Corporate Technology, Princeton, New Jersey, USA
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Abstract
Neuroimaging is essential to stroke diagnosis and management. To date, the non-contrast CT has served as our main diagnostic tool. Although brain parenchymal changes visible on CT do provide valuable prognostic information, they provide limited insight into the potential for tissue salvage in response to reperfusion therapy, such as thrombolysis. Newer advanced CT and MRI based imaging techniques have increased the detection sensitivity for hyperacute and chronic parenchymal changes, including ischemia and hemorrhage, permit visualization of blood vessels and cerebral blood flow. This review outlines the basic principles underlying acquisition and interpretation of these newer imaging modalities in the setting of acute stroke. The utility of advanced brain parenchymal and blood flow imaging in the context of acute stroke patient management is also discussed. Part II in this series is a discussion of how these techniques can be used to rationally select appropriate patients for thrombolysis based on pathophysiological data.
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Abstract
Neuroimaging has expanded beyond its traditional diagnostic role and become a critical tool in the evaluation and management of stroke. The objectives of imaging include prompt accurate diagnosis, treatment triage, prognosis prediction, and secondary preventative precautions. While capitalizing on the latest treatment options and expanding upon the "time is brain" doctrine, the ultimate goal of imaging is to maximize the number of treated patients and improve the outcome of one the most costly and morbid disease. A broad overview of comprehensive multimodal stroke imaging is presented here to affirm its utilization.
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Affiliation(s)
- Elizabeth Tong
- Neuroradiology Division, Department of Radiology, University of Virginia, Charlottesville, Virginia
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Nael K, Meshksar A, Ellingson B, Pirastehfar M, Salamon N, Finn P, Liebeskind DS, Villablanca JP. Combined low-dose contrast-enhanced MR angiography and perfusion for acute ischemic stroke at 3T: A more efficient stroke protocol. AJNR Am J Neuroradiol 2014; 35:1078-84. [PMID: 24503557 DOI: 10.3174/ajnr.a3848] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE There is need to improve image acquisition speed for MR imaging in evaluation of patients with acute ischemic stroke. The purpose of this study was to evaluate the feasibility of a 3T MR stroke protocol that combines low-dose contrast-enhanced MRA and dynamic susceptibility contrast perfusion, without additional contrast. METHODS Thirty patients with acute stroke who underwent 3T MR imaging followed by DSA were retrospectively enrolled. TOF-MRA of the neck and brain and 3D contrast-enhanced MRA of the craniocervical arteries were obtained. A total of 0.1 mmol/kg of gadolinium was used for both contrast-enhanced MRA (0.05 mmol/kg) and dynamic susceptibility contrast perfusion (0.05 mmol/kg) (referred to as half-dose). An age-matched control stroke population underwent TOF-MRA and full-dose (0.1 mmol/kg) dynamic susceptibility contrast perfusion. The cervicocranial arteries were divided into 25 segments. Degree of arterial stenosis on contrast-enhanced MRA and TOF-MRA was compared with DSA. Time-to-maximum maps (>6 seconds) were evaluated for image quality and hypoperfusion. Quantitative analysis of arterial input function curves, SNR, and maximum T2* effects were compared between half- and full-dose groups. RESULTS The intermodality agreements (k) for arterial stenosis were 0.89 for DSA/contrast-enhanced MRA and 0.63 for DSA/TOF-MRA. Detection specificity of >50% arterial stenosis was lower for TOF-MRA (89%) versus contrast-enhanced MRA (97%) as the result of overestimation of 10% (39/410) of segments by TOF-MRA. The DWI-perfusion mismatch was identified in both groups with high interobserver agreement (r = 1). There was no significant difference between full width at half maximum of the arterial input function curves (P = .14) or the SNR values (0.6) between the half-dose and full-dose groups. CONCLUSIONS In patients with acute stroke, combined low-dose contrast-enhanced MRA and dynamic susceptibility contrast perfusion at 3T is feasible and results in significant scan time and contrast dose reductions.
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Affiliation(s)
- K Nael
- From the Department of Medical Imaging (K.N., A.M.), University of Arizona, Tucson, Arizona
| | - A Meshksar
- From the Department of Medical Imaging (K.N., A.M.), University of Arizona, Tucson, Arizona
| | - B Ellingson
- Department of Radiological Sciences (B.E., M.P., N.S., P.F., J.P.V.)
| | - M Pirastehfar
- Department of Radiological Sciences (B.E., M.P., N.S., P.F., J.P.V.)
| | - N Salamon
- Department of Radiological Sciences (B.E., M.P., N.S., P.F., J.P.V.)
| | - P Finn
- Department of Radiological Sciences (B.E., M.P., N.S., P.F., J.P.V.)
| | - D S Liebeskind
- Department of Neurology, Stroke Center (D.S.L.), University of California, Los Angeles, Los Angeles, California
| | - J P Villablanca
- Department of Radiological Sciences (B.E., M.P., N.S., P.F., J.P.V.)
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12
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Ferré JC, Raoult H, Breil S, Carsin-Nicol B, Ronzière T, Gauvrit JY. Supra-aortic arteries: three-dimensional time-resolved k-t BLAST contrast-enhanced MRA using a nondedicated body coil at 3 tesla in acute ischemic stroke. J Magn Reson Imaging 2013; 40:1056-63. [PMID: 24222649 DOI: 10.1002/jmri.24466] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 09/14/2013] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To assess the image quality and diagnostic performance achieved by using supra-aortic 3D-TR-CE-k-t BLAST MRA and a nondedicated body coil as compared with conventional CE-MRA in patients with acute ischemic stroke. MATERIALS AND METHODS In this prospective study, 36 consecutive patients with a suspected acute ischemic stroke underwent both k-t BLAST MRA and conventional CE-MRA. Image quality was assessed using visual and quantitative criteria and the techniques were compared. Both techniques were compared for degree of visual and quantitative measurement of carotid stenosis. RESULTS Delineation of vessel lumen and overall diagnostic confidence were significantly better with CE-MRA, respectively 3.4 ± 0.5 and 3.3 ± 0.6 (mean score ± SD), than with k-t BLAST MRA, respectively 2.8 ± 0.4 and 2.9 ± 0.5 (P < 0.02). SNR and CNR were significantly higher for k-t BLAST MRA, respectively 33.5 ± 19.3 and 27.9 ± 19.3, than for CE-MRA, respectively 25.7 ± 10 and 20.4 ± 8.4 (P < 0.03). Intertechnique agreement was good for carotid stenosis characterization (κ = .763). For the 14 relevant stenosis, stenosis measurements were highly correlated between techniques (0.96; P < 0.0001). The Bland-Altman plot showed a low bias in assessment of the degree of stenosis (mean bias 2.1% ± 7.7). CONCLUSION k-t BLAST MRA using a nondedicated coil offering and dynamic information was a effective diagnostic tool for detection and characterization of carotid stenosis.
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Affiliation(s)
- Jean-Christophe Ferré
- CHU Rennes, Department of Neuroradiology, University Hospital of Rennes, Rennes, France
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Macintosh BJ, Graham SJ. Magnetic resonance imaging to visualize stroke and characterize stroke recovery: a review. Front Neurol 2013; 4:60. [PMID: 23750149 PMCID: PMC3664317 DOI: 10.3389/fneur.2013.00060] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/09/2013] [Indexed: 11/21/2022] Open
Abstract
The global burden of stroke continues to grow. Although stroke prevention strategies (e.g., medications, diet, and exercise) can contribute to risk reduction, options for acute interventions (e.g., thrombolytic therapy for ischemic stroke) are limited to the minority of patients. The remaining patients are often left with profound neurological disabilities that substantially impact quality of life, economic productivity, and increase caregiver burden. In the last decade, however, the future outlook for such patients has been tempered by movement toward the view that the brain is capable of reorganizing after injury. Many now view brain recovery after stroke as an area of scientific research with large potential for therapeutic advances, far into the future (Broderick and William, 2004). As a probe of brain anatomy, function and physiology, magnetic resonance imaging (MRI) is a non-invasive and highly versatile modality that promises to play a particularly important role in such research. Here we provide a basic review of MRI physical principles and applications for assessing stroke, looking toward the future role MRI may play in improving stroke rehabilitation methods and stroke recovery.
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Affiliation(s)
- Bradley J Macintosh
- Physical Sciences Platform, Sunnybrook Research Institute Toronto, ON, Canada ; Heart and Stroke Foundation Centre for Stroke Recovery, Sunnybrook Research Institute Toronto, ON, Canada ; Department of Medical Biophysics, University of Toronto Toronto, ON, Canada
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Campeau NG, Huston J. Vascular disorders--magnetic resonance angiography: brain vessels. Neuroimaging Clin N Am 2012; 22:207-33, x. [PMID: 22548929 DOI: 10.1016/j.nic.2012.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Magnetic resonance angiography (MRA) of the brain obtained at 3 T imaging has made a significant clinical impact. MRA benefits from acquisition at higher magnetic field strength because of higher available signal-to-noise ratio and improved relative background suppression due to magnetic field strength-related T1 lengthening. Parallel imaging techniques are ideally suited for high-field MRA. Many of the developments that have made 3 T MRA of the brain successful can be regarded as enabling technologies that are essential for further development of 7 T MRA, which brings additional challenges.
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Affiliation(s)
- Norbert G Campeau
- Division of Neuroradiology, Mayo Clinic, West 2 Mayo Building, 200 First Street Southwest, Rochester, MN 55905, USA.
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Latchaw RE, Alberts MJ, Lev MH, Connors JJ, Harbaugh RE, Higashida RT, Hobson R, Kidwell CS, Koroshetz WJ, Mathews V, Villablanca P, Warach S, Walters B. Recommendations for imaging of acute ischemic stroke: a scientific statement from the American Heart Association. Stroke 2009; 40:3646-78. [PMID: 19797189 DOI: 10.1161/strokeaha.108.192616] [Citation(s) in RCA: 291] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Diagnosis and neurosurgical treatment of intracranial vascular occlusive syndromes. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2009; 11:212-20. [PMID: 19433016 DOI: 10.1007/s11936-009-0022-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Intracranial atherosclerosis represents the most prevalent form of intracranial vascular occlusive disease in the adult population and is a major contributor to ischemic stroke. The most reliable method for diagnosing intracranial stenosis relies on conventional catheter angiography; MRI and CT imaging and transcranial Doppler currently are valuable screening tools, and ongoing advances in these modalities may render angiography nonessential for accurate diagnosis in the future. Given the potential for hemodynamic compromise from intracranial occlusive disease, a variety of imaging modalities may be used to assess the adequacy of cerebral perfusion, relying on direct measurements of oxygen extraction fraction or the response to vasodilatory stimuli to determine hemodynamic status. The modalities are well established for assessing the anterior circulation but have proven less useful for the posterior circulation, in which direct measurements of large vessel flow using quantitative magnetic resonance angiography may be more valuable. Surgical and endovascular interventions for treating intracranial stenosis are not, as of yet, proven therapies for routine management. Extracranial-intracranial bypass surgery and endovascular angioplasty and stenting are being investigated in randomized trials to evaluate their efficacy in treating intracranial vascular occlusive disease.
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Lee WK, Mossop PJ, Little AF, Fitt GJ, Vrazas JI, Hoang JK, Hennessy OF. Infected (mycotic) aneurysms: spectrum of imaging appearances and management. Radiographics 2009; 28:1853-68. [PMID: 19001644 DOI: 10.1148/rg.287085054] [Citation(s) in RCA: 202] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Infected aneurysms are uncommon. The aorta, peripheral arteries, cerebral arteries, and visceral arteries are involved in descending order of frequency. Staphylococcus and Streptococcus species are the most common causative pathogens. Early clinical diagnosis of infected aneurysms is challenging owing to their protean manifestations. Clinically apparent infected aneurysms are often at an advanced stage of development or are associated with complications, such as rupture. Nontreatment or delayed treatment of infected aneurysms often has a poor outcome, with high morbidity and mortality from fulminant sepsis or hemorrhage. Current state-of-the-art imaging modalities, such as multidetector computed tomography and magnetic resonance imaging, have replaced conventional angiography as minimally invasive techniques for detection of infected aneurysms in clinically suspected cases, as well as characterization of infected aneurysms and vascular mapping for treatment planning in confirmed cases. Doppler ultrasonography allows noninvasive assessment for infected aneurysms in the peripheral arteries. Imaging features of infected aneurysms include a lobulated vascular mass, an indistinct irregular arterial wall, perianeurysmal edema, and a perianeurysmal soft-tissue mass. Perianeurysmal gas, aneurysmal thrombosis, aneurysmal wall calcification, and disrupted arterial calcification at the site of the infected aneurysm are uncommon findings. Imaging-guided endovascular stent-graft repair and embolotherapy can be performed in select cases instead of open surgery. Familiarity with the imaging appearances of infected aneurysms should alert the radiologist to the diagnosis and permit timely treatment, which may include endovascular techniques.
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Affiliation(s)
- Wai-Kit Lee
- Department of Medical Imaging, St Vincent's Hospital, University of Melbourne, Fitzroy, Victoria, Australia.
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Intra-individual Crossover Comparison of Gadobenate Dimeglumine and Gadopentetate Dimeglumine for Contrast-Enhanced Magnetic Resonance Angiography of the Supraaortic Vessels at 3 Tesla. Invest Radiol 2008; 43:695-702. [DOI: 10.1097/rli.0b013e31817d1505] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Lohan DG, Krishnam M, Tomasian A, Saleh R, Finn JP. Time-Resolved MR Angiography of the Thorax. Magn Reson Imaging Clin N Am 2008; 16:235-48, viii. [DOI: 10.1016/j.mric.2008.02.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Buis DR, Lagerwaard FJ, Dirven CMF, Barkhof F, Knol DL, van den Berg R, Slotman BJ, Vandertop WP. Delineation of brain AVMs on MR-Angiography for the purpose of stereotactic radiosurgery. Int J Radiat Oncol Biol Phys 2007; 67:308-16. [PMID: 17189079 DOI: 10.1016/j.ijrobp.2006.08.075] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Revised: 07/31/2006] [Accepted: 08/29/2006] [Indexed: 10/23/2022]
Abstract
PURPOSE To assess the dosimetric consequences of brain arteriovenous malformation (bAVM) delineation on magnetic resonance angiography (MRA) for the purpose of stereotactic radiosurgery. METHODS AND MATERIALS Three observers contoured a bAVM in 20 patients, using digital subtraction angiography (V(DSA)) and three-dimensional time-of-flight MRA (V(MRA)). Displacement between contours was calculated. Agreement and differences between observers and imaging modalities were assessed. A standardized treatment plan with dynamic conformal arcs was generated and dosimetric coverage of all contours and the volume of normal brain tissue within the high dose region was determined. RESULTS The generalized reliability coefficient was "fair" for target volume (0.79), but "poor" for displacement (0.35). V(MRA) was larger than V(DSA) (5.0 vs. 4.0 mL, p = 0.001). No difference in displacement was found (2.8 vs. 2.5 mm, p = 0.156). Dosimetric coverage of V(MRA) was 62.9% (95% CI, 56.9-68.8) when V(DSA) was used as planning target volume, and coverage of V(DSA) was 83.5% (95% CI, 78.1-88.8) when V(MRA) was used for planning (p < 0.001). The mean volume of normal brain within the 80% isodose was larger when the bAVM was delineated on MRA (0.7 vs. 1.0 mL (p = 0.02) for targets < or =3 mL and 3.7 vs. 7.0 mL (p = 0.01) for targets >3 mL). CONCLUSIONS Brain arteriovenous malformations delineated on MRA are larger and more randomly displaced. However, for bAVMs < or =3 mL, the difference in volume of normal brain tissue within the high-dose region does not seem to be clinically relevant. Therefore, MRA-images might be used as the sole imaging modality for the radiosurgical treatment of bAVMs < or =3 mL when the bAVM is located in a noneloquent position.
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Affiliation(s)
- Dennis R Buis
- Department of Neurosurgery, VU University Medical Center, Amsterdam, The Netherlands.
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Abstract
Stroke is a devastating disease with a complex pathophysiology. It is a major cause of death and disability in North America. To fully characterize its extent and effects, one requires numerous specialized anatomical and functional MR techniques, specifically diffusion-weighted imaging, MR angiography, and perfusion-weighted imaging. The advent of 3.0 T clinical scanners has the potential to provide higher quality information in potentially less time compared with 1.5 T stroke-specific MR imaging protocols. This article gives a brief overview of stroke, presents the principles and clinical applications of the relevant MR techniques required for diagnostic stroke imaging at high field, and discusses the advantages, challenges, and limitations of 3.0 T imaging as they relate to stroke.
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