VADs may often encroach on the arterial lumen, narrowing it and drawing one's attention to the area of abnormality. In our center, CT angiography (CTA) has become the primary technique for evaluation of suspected acute neurologic vascular disorders. Additionally, it has the ability to further evaluate patients for a variety of clinical conditions associated with VAD, including stroke, subarachnoid hemorrhage, and cervical spine abnormalities. 5 The relative advantage of cross-sectional imaging over conventional angiography is that it may better demonstrate extraluminal abnormalities. This may consist of MR imaging, MR angiography (MRA), and/or multisection helical CT angiography. In our center and many others, noninvasive imaging for suspected dissections has complemented or even replaced conventional angiography. 2- 4 Stenosis is by far the most common finding resulting in luminal narrowing by subintimal hematoma formation. 1 This can demonstrate the typical angiographic findings of an intimal flap: irregularity and/or stenosis of the vessel, the string sign (arising as a result of a dissection that extends circumferentially around the lumen over a long segment), the double lumen sign, pseudoaneurysm formation, or complete occlusion. Conventional angiography has long been considered the gold standard for imaging of vertebral artery dissections. The imaging findings of acute vertebral artery dissection (VAD) are well known. We caution against using only luminal-opacifying techniques such as contrast-enhanced MRA or conventional angiography to exclude VAD because they are limited in the evaluation of mural hematoma. In our center, this clinically occult VAD would influence management, with patients usually treated with antiplatelet agents. Our study confirms that in cases of the “suboccipital rind” sign, the lumen appears normal in caliber, with wall thickening as the only imaging sign of VAD. 001).ĬONCLUSIONS: Cross-sectional vascular imaging is often performed with multisection helical CTA for a variety of concerns, some without neurologic symptoms. There was a significant difference in the ratio of lumen diameter/lumen+wall diameter in dissected segments compared with controls ( P <. The average wall thickness of the dissection group was 2.96 mm greater than that for the control group ( P <. RESULTS: There was no evidence of luminal tapering or narrowing in the dissected VAs compared with controls ( P =. The VA luminal diameter, the wall thickness (total diameter−luminal diameter), and the ratio of luminal diameter/total diameter were measured along 5 adjacent V3 segments and were compared between the 2 groups. A control group of 50 patients was randomly recruited from a group of patients undergoing CTA. MATERIALS AND METHODS: Our imaging data base was reviewed for cases of acute VAD and the presence of a “suboccipital rind” sign. The purpose of our study was to review the CTA imaging characteristics of patients with VAD in the V3 portion compared with normal controls. We highlight the importance of recognizing this finding, the “suboccipital rind” sign, in the V3 portion, a segment commonly affected in VAD. This type of dissection is easily overlooked if only lumen-opacifying studies such as contrast MR angiography (MRA) or conventional angiography are performed. The arterial lumen at the dissection site was normal in caliber. We describe cases of acute vertebral artery dissection (VAD) in which the only abnormality on CTA was a characteristic thickening of the wall of the V3 portion of the vertebral artery (VA).
With thin-section multisection CTA, the resolution of vessel wall imaging has improved. BACKGROUND AND PURPOSE: CT angiography (CTA) is widely used and may be the only vascular imaging technique ordered for emergent evaluation of neurovascular disease.
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