Spontaneous Middle Cerebral Artery Dissection Demonstrated by High-Resolution T1-Weighted 3D Image

Case Report A 39-year-old, right-handed man was admitted to our hospital because of sudden onset of right hemiparesis and aphasia. His medical history included atopic dermatitis, and included no episodes of trauma. He was alert on admission; however, his speech and comprehension were impaired, and was assessed a National Institutes of Health Stroke Scale score of 15. Brain computed tomography showed obscuration of the lentiform nucleus on the left side. Computed tomography angiography (CTA) demonstrated an occlusion of the left MCA at the horizontal segment. Laboratory examination yielded unremarkable results. Administration of intravenous recombinant tissue plasminogen activator (IV rtPA) was started at 164 min after symptom onset (alteplase, 0.6 mg/ kg). However, no neurological improvement was observed. Transcranial color-coded flow velocity measurements demonstrated reperfusion of the left MCA just after IV rt-PA administration, and 1.5T MRI detected an acute infarction in the left putamen, insular cortex, and corona radiata ( fig. 1 a). Magnetic resonance angiography results could not be evaluated because of motion artifacts. On day 4, CTA showed dilatation of the left MCA ( fig. 1 b) and the double lumen sign ( fig. 1 c), on the basis of which spontaneous MCAD was strongly suggested. However, atherothrombic occlusion, while unlikely given the circumstances, could not be completely ruled out at the time, since the fat-saturated T1-weighted imaging [4] needed to make an unambiguous diagnosis of MCAD was not performed. On day 17, fast spoiled gradient-echo images Spontaneous cervicocephalic arterial dissection is an uncommon cause of stroke [1] . Segments of the middle cerebral artery (MCA) are rarely involved, and the incidence of MCA dissection (MCAD) is reported to be 4% of the spontaneous cervicocephalic arterial dissections in Japan [2] . A previous report suggests that magnetic resonance imaging (MRI) may be useful for detecting intracranial vertebrobasilar artery dissection [3] , although the applicability in MCAD patients is unknown. Here, we report a patient who had MCAD with characteristic lesions, which was demonstrated by high-resolution T1-weighted 3D images obtained using a 3-tesla MRI (3T MRI) system. Published online: October 12, 2013