Superb microvascular imaging is useful for diagnosis and follow‐up of common carotid artery dissection

A 71-year-old woman presented with sudden right-sided neck pain, impaired consciousness, and left hemiplegia. Neurological examination revealed impaired consciousness, right deviation, dysarthria, complete left hemiplegia, and left sensory disturbance. Diffusion-weighted magnetic resonance (MRI) indicated acute infarctions in the right middle cerebral artery area, and MR angiography showed no right internal carotid artery (Figure 1A,B). Computed tomography angiography revealed a tapered occlusion of the right common carotid artery (CCA) (Figure 1C,D). Carotid ultrasonography (CUS) did not show a thrombus (Figure 1E). On day 7, B-mode and color Doppler CUS showed no flow in the CCA (Figure 1F,G). Monochrome superb microvascular imaging (SMI) (Canon Medical Systems®) demonstrated an intramural thrombus in the pseudolumen (Figure 1H), and color-coded SMI showed low blood flow of the true lumen (Figure 1I). On day 13, T1-weighted black-blood MR imaging showed an intramural thrombus (Figure 1J). Hence, a diagnosis of right idiopathic CCA dissection was made. On day 14, color-coded SMI indicated recanalization flow in the true lumen (Figure 1K). Idiopathic CCA dissection is rare1, 2 but can be diagnosed using CUS. SMI can evaluate low blood flow3, 4 and is useful for diagnosing and following up CCA dissection. The named authors have no conflict of interest, financial or otherwise.