Most examinations require a T1-weighted vessel wall sequence before and after intravenous gadolinium contrast. Low-velocity flow can cause intravascular signal loss on time-of-flight MRA, so in patients who have pronounced luminal narrowing or dilation, it is helpful to add a gadolinium-bolus MRA to accurately define the contour of the lumen (ie, the boundary between the lumen and wall). Time-of-flight MRA is mainly used to characterize luminal abnormality and act as a localizer for subsequent vessel wall sequences. Ongoing advances in MR imaging technology, including higher magnetic field strength, 2 may enable further increases in spatial resolution and image quality. Most experienced centers are using isotropic voxel dimensions in the 0.4- to 0.7-mm range for 3D acquisitions. At 3T with a 3D sequence, a voxel size of 0.5 mm isotropic is a reasonable starting point ( Fig 1 B), and it is possible to cover the circle of Willis and second-/third-order branches in 7–10 minutes. At 3T with a 2D sequence, a voxel size of 2.0 × 0.4 × 0.4 mm provides a reasonable balance between spatial resolution and signal-to-noise ratio, with a scan duration of approximately 5–7 minutes for a 2- to 4-cm-thick section of tissue ( Fig 1 A). The higher signal-to-noise ratio at 3T than at 1.5T is advantageous for intracranial VW-MR imaging and, in many cases, necessary. In addition, vessel wall disease often results in wall thickening, which increases its conspicuity. However, it is possible to image the intracranial arterial wall because the wall generates detectable MR imaging signal and one can suppress the MR imaging signal arising from neighboring blood and CSF within the voxel. The normal middle cerebral artery and basilar artery wall thickness is 0.2–0.3 mm, which is approximately one-tenth of the luminal diameter 1 and smaller than the VW-MR imaging voxel dimensions currently achievable. ![]() ![]() The principal technical requirements for intracranial VW-MR imaging are the following: 1) high spatial resolution, 2) multiplanar 2D acquisitions or 3D acquisitions, 3) multiple tissue weightings, and 4) suppression of signal in luminal blood and CSF. The technical sections that follow provide general recommendations on the development of an intracranial VW-MR imaging protocol, and we are also launching a dynamic document (via the American Society of Neuroradiology Web site) through which experienced centers can describe their MR imaging systems and the specific pulse sequences and scan parameters that they have found useful. Selection of sequences and scan parameters for VW-MR imaging is highly dependent on the particular scanner hardware and software available at a center. ![]() Until such sequences are widely available, it is possible to adjust the scan parameters of existing sequences and obtain vessel wall images of sufficient quality for clinical use. Find out the real cause of your pain at M1 Imaging! M1 Imaging Center: We See You Like No One Else Does.The American Society of Neuroradiology Vessel Wall Imaging Study Group is working with MR imaging vendors to promote the development and dissemination of commercial pulse sequences that are optimized for intracranial VW-MR imaging. You can’t get the right treatment if you can’t see the whole picture. High-field coils for Targeted Joint Imaging.Traumatic Brain Injury + Susceptibility Weighted Imaging.Open MRI with 70 cm wide bore that allows up to 550 lbs.NeuroQuant software for quantitative MRI measurement that leads to the most reliable, objective reads.Led by a renowned board-certified musculoskeletal and neuroradiologist and an entrepreneurial health administrator with decades of collective experience in the field, M1 Imaging provides the best MRI diagnostics in Michigan. M1 Imaging works with referring physicians including orthopedic surgeons, pain management and rehabilitation doctors, neurologists, neurosurgeons and chiropractors, as well as case managers, sports teams and others interested in achieving the best in medical imaging we also directly serve patients, who are their own best advocates. You receive the right diagnosis from the start, leading to proper treatment you deserve to truly heal. ![]() More accurate imaging and expert radiology readings give a clearer picture of your health and what you need to recover.Īt M1 Imaging Center, with several convenient locations near major highways, including Warren and Berkley, serving all Metro Detroit, and our newest Grand Rapids location serving all of West Michigan, we utilize the latest technology to discover the true cause of pain. M1 Imaging focuses solely on providing the best medical imaging in Michigan in the comfort of a private, non-hospital setting with expert diagnostics to increase the quality and outcomes of patient care.
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