Acute M1 occlusion with ischemic penumbra (CT perfusion)

Case contributed by Craig Hacking


Sudden onset right hemiparesis and facial droop. Onset of symptoms 60 min before scan.

Patient Data

Age: 75 years
Gender: Female

Grey-white matter differentiation is maintained. Hyperdensity in the proximal aspect of the M1 segment of the left MCA. No hemorrhage, mass effect or midline shift. The ventricles and basal cisterns are normal.

Filling defect of approximately 4 mm within the M1 segment of the left MCA. Distal vessel flow is preserved. Good collateral flow.

Patent dural venous sinuses.

Large area of increased MTT, TTD and TTP with decreased CBF but preserved CBV in the left MCA territory representing penumbra. Small posterior focus of decreased CBF and decreased CBV representing core infarct.  

Acute left MCA territory cerebral infarction secondary to an occlusive thrombus within the M1 segment of the left MCA. Predominately penumbra within the left MCA territory, with a small proportion of core infarct.

The patient proceeded immediately to the neurointerventional angiographic suite for mechanical thrombectomy.

Mechanical thrombectomy


Left M1 occlusion. Mechanical thrombectomy performed 120 minutes after onset. Successful first pass, post thrombectomy TICI 3.

Symptoms completely resolved in recovery bay.

Case Discussion

Good example of a M1 occlusion in a slow progressor with good collaterals. The CT perfusion color maps show predominantly penumbra in the left MCA territory.

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