Fig. 5

Left internal carotid artery (ICA) dissection with acute watershed infarct in a 42-year-old man with sudden onset of speech disturbance. a MR angiography, single partition at the level of the skull base showing dissection of the left ICA, which is characteristically enlarged with high-signal-intensity methaemoglobin (arrowheads) representing the intramural thrombus and a small eccentric lumen (arrow). b MR angiography, coronal MIP: narrowing of the ICA in its vertical segment just below the skull base (arrow). c DWI, axial image: acute watershed infarct in the left centrum semiovale. d SWI minIP: improved visualisation of the veins of the left cerebral hemisphere, which is related to increased oxygen extraction in the ischaemic penumbra and corresponds to the hypoperfusion deficit shown by the mean transit time (MTT) map. e Perfusion MRI, MTT map, showing delayed transit time in the left middle cerebral artery (MCA) territory. f Intra-arterial digital subtraction angiography (DSA), left carotid angiogram, confirming the ICA stenosis (arrow). g Intra-arterial DSA: the patient was treated using stent placement, which resulted in partial restoration of the vessel lumen. h Perfusion MRI, MTT map 24 h after stent placement: complete resolution of the perfusion deficit. i SWI minIP, normalisation of the venous drainage of the left hemisphere