Neuroradiology Case of the Week

Case 24

Manoj Ketkar, MD, Francisco Garcia-Morales, MD, S. Ekholm, MD, PhD,
and P-L Westesson, MD, PhD, DDS

Clinical Presentation: An 83-year-old female presented with right-sided weakness. CT scan of head was requested for the clinical suspicion of an acute stroke.

Radiological Findings: A diffuse area of low attenuation is noted in the left frontal parietal lobes and the distribution of the MCA. There is minimal effacement of the overlying cortical sulci, consistent with acute cerebellar swelling. No evidence of hemorrhage is identified (Fig. 1A & B).

Figure 1A	Figure 1B
Figure 1 A & B: Axial non-contrast CT scan of the head shows an area of low attenuation in the left MCA territory with effacement of the cortical sulci, consistent with an acute infarct.

Diagnosis: An acute left MCA territory infarct.

Discussion:
   Stroke is essentially the clinical diagnosis. The role of immediate CT scan in management of acute cerebral infarction is twofold:

1. To diagnose or exclude intracerebral hemorrhage.
2. Identify the presence of underlying structure lesions such as tumor, vascular malformations or subdural hematomas that can mimic stroke clinically.

   Although almost 60% of CT scans obtained within the first few hours of cerebral infarction are normal several early signs of acute stroke can often be identified in stroke less than 4-6 hours old. These signs include hyperattenuating artery usually the middle cerebral artery, the so-called dense MCA sign. Obscuration of lentiform nucleus, gray-white interface loss along the lateral insula, the so-called insular ribbon sign, and effacement of gray- white junction around the cortex.
   Within 1-3 days an increasing mass effect is noted in the region of the infarct with a wedge-shaped area of low density involving both gray and white matter. Hemorrhagic transformation may occur particularly in the basal ganglia region and cortex [1].

References:

1. Osborn A. Diagnostic Neuroradiology. CV Mosby, St. Louis, MO, 1944, pp. 344-347.