CT Temporal Bone Without IV Contrast There is no relevant literature regarding the use of CT temporal bone without IV contrast in the evaluation of suspected VBI. CTA Head and Neck With IV Contrast CTA allows for the evaluation of the course and luminal caliber of the studied arteries. CTA can also detect luminal filling defects, which may include thrombus, embolus, atherosclerotic plaque, dissection flap, or vascular web. In cases of vertebral artery dissection confirmed by conventional angiography, CTA has the highest reported sensitivity (100%), followed by MRA (77%) and Doppler US (71%), in a systematic review of 75 observational studies. Because symptomatic dissection may involve any portion of the vertebral artery, from the origin at the aortic arch branch vessels to the basilar artery, the entirety of the vessel should be included for evaluation [14]. MRA Head and Neck With IV Contrast MRA allows for evaluation of the course and luminal caliber of the arteries. MRA can also detect luminal filling defects, which may include thrombus, embolus, atherosclerotic plaque, dissection flap, or vascular web. MRA of the head and neck can be performed without IV contrast, with IV contrast, or as a combination of without and with IV contrast. Although 3-D time-of-flight MRA of the head is typically diagnostic without the use of IV gadolinium- based contrast agents, MRA of the neck is often best performed with contrast for better evaluation of the vessels with increased spatial resolution and decreased flow-related artifacts. In a study comparing the diagnostic performance of contrast-enhanced MRA of the neck to digital subtraction angiography in evaluation of vertebral artery origin stenosis, the sensitivity, specificity, and accuracy of MRA were shown to be as high as 97%, 98%, and 93%, respectively, in 49 patients [69]. However, MRA has not demonstrated significant differences in the degree of arterial stenosis between symptomatic patients with VBI and asymptomatic controls [13].
Dizziness and Ataxia. CT Temporal Bone Without IV Contrast There is no relevant literature regarding the use of CT temporal bone without IV contrast in the evaluation of suspected VBI. CTA Head and Neck With IV Contrast CTA allows for the evaluation of the course and luminal caliber of the studied arteries. CTA can also detect luminal filling defects, which may include thrombus, embolus, atherosclerotic plaque, dissection flap, or vascular web. In cases of vertebral artery dissection confirmed by conventional angiography, CTA has the highest reported sensitivity (100%), followed by MRA (77%) and Doppler US (71%), in a systematic review of 75 observational studies. Because symptomatic dissection may involve any portion of the vertebral artery, from the origin at the aortic arch branch vessels to the basilar artery, the entirety of the vessel should be included for evaluation [14]. MRA Head and Neck With IV Contrast MRA allows for evaluation of the course and luminal caliber of the arteries. MRA can also detect luminal filling defects, which may include thrombus, embolus, atherosclerotic plaque, dissection flap, or vascular web. MRA of the head and neck can be performed without IV contrast, with IV contrast, or as a combination of without and with IV contrast. Although 3-D time-of-flight MRA of the head is typically diagnostic without the use of IV gadolinium- based contrast agents, MRA of the neck is often best performed with contrast for better evaluation of the vessels with increased spatial resolution and decreased flow-related artifacts. In a study comparing the diagnostic performance of contrast-enhanced MRA of the neck to digital subtraction angiography in evaluation of vertebral artery origin stenosis, the sensitivity, specificity, and accuracy of MRA were shown to be as high as 97%, 98%, and 93%, respectively, in 49 patients [69]. However, MRA has not demonstrated significant differences in the degree of arterial stenosis between symptomatic patients with VBI and asymptomatic controls [13].