Published ahead of print on July 17, 2008
doi: 10.3174/ajnr.A1189
Comparison of Multidetector CT Angiography and MR Imaging of Cervical Artery Dissection
A.T. Vertinskya,
N.E. Schwartzb,
N.J. Fischbeinc,
J. Rosenbergc,
G.W. Albersb and
G. Zaharchukc
a Department of Radiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
b Department of Neurology and Neurological Sciences, Stanford Stroke Center, Stanford University Medical Center, Stanford, Calif
c Department of Radiology, Stanford University, Stanford, Calif
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Fig 1. CT/CTA imaging of multivessel dissection (right ICA and VA) provides more detailed information than MR imaging/MRA about vessel morphology. Conventional cerebral angiographic images of the right ICA (A) and right VA (B). Curved planar reformat images from the CTA study of the right ICA (C) and right VA (D). Both demonstrate vessel wall irregularity, mild luminal narrowing, and pseudoaneurysm of the right ICA (arrows). E, Corresponding MIP image from contrast-enhanced MRA shows both dissections (arrows), but with less clear depiction than that on CTA. F, Axial T1-weighted fat-suppressed image demonstrates a crescent sign consistent with intramural hematoma around both the right ICA and VA (arrows).
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Fig 2. CT/CTA and MR imaging/MRA of a left ICA dissection provide similar information about vessel morphology, but MR imaging is deemed superior for making the diagnosis, particularly because of detection of acute stroke. A, Axial T1-weighted fat-suppressed image demonstrates a crescent sign around the left ICA (arrow). B, CTA curved planar reformat shows irregularity and thickening of the left ICA wall with calcified plaque. These findings are not specific for dissection and could be due to atherosclerosis. C, Contrast-enhanced MRA MIP reformat demonstrates the similar appearance of the irregular left ICA. D and E, Noncontrast CT (D) does not show the acute infarct, which is clearly identified in the left middle cerebral artery–anterior cerebral artery watershed territory on DWI (E).
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Fig 3. CT/CTA and MR imaging/MRA provide different advantages in this case of right ICA dissection, but diagnosis is made with equal confidence on both techniques. A and B, Noncontrast CT image (A) shows mild hypoattenuation involving the right basal ganglia (arrow), confirmed as an acute stroke with DWI (B). C, Axial source image from CTA shows expansion of the outer wall of the right ICA consistent with wall thickening as well as narrowing of the vessel lumen (arrow). D, Axial T1-weighted fat-suppressed MR image demonstrates a crescent sign (arrow) around the right ICA.
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Fig 4. Example of a long-segment high-grade stenosis (string sign) identified on CTA, which appeared occluded on MR imaging/MRA. A and B, Curved planar reformatted images of the left ICA demonstrate flamelike tapering of the proximal vessel with wall thickening and long-segment high-grade stenosis (arrow). C, Axial plane from CTA shows the tiny residual lumen of the vessel (arrow). D, Contrast-enhanced MRA acquired on the same day demonstrates apparent occlusion just distal to the carotid bifurcation (arrow). E, T1-weighted fat-suppressed axial image demonstrates methemoglobin in the left ICA wall. F and G, Axial source images from 2D time-of-flight MR angiography show the T1 shinethrough of the methemoglobin, but the absence of flow-related enhancement in the left distal cervical ICA.
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Fig 5. Right vertebral artery dissection with a pseudoaneurysm seen on CTA, which is not visualized on MR imaging/MRA. A, Curved planar reformatted image from CTA of the distal right vertebral artery demonstrates irregularity (arrow) as well as a small distal pseudoaneurysm. B, An axial CTA source image shows contrast within the true lumen and the pseudoaneurysm anteriorly (arrow). C, Contrast-enhanced MRA demonstrates the irregularity associated with the dissection, but not the pseudoaneurysm. D, 2D time-of-flight MRA depicts the narrowed true lumen but does not show the pseudoaneurysm, presumably due to saturation of slow-flowing blood.
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