DX: Acute-hyperacute stroke of the right MCA, M2 territory

Ok here's the conclusion of the case of an elderly patient with history of sudden loss of conciousness and seizures with a low Glasgow coma scale. This happened 3 hours ago according to a relative that came with patient.

As you all noticed it was divided in two parts. The first one was a complete CT brain scan with no IV contrast. The second part was a single axial brain slice of a Diffusion Weighted Image (DWI) sequence. The whole point of dividing in two parts was to compare subtle CT findings. As I wrote in the previous post, the indication of the DWI study was because of "ambiguity" of those findings.

Here are the CT findings (click in image to enlarge):

a.

In picture (a) we see a bright hyperdense round image in topography of M1 MCA just after leaving the Willis circle. This is what is called a "hyperdense MCA sign" or simply MCA dot sign; it manifests because there's an increased amount of intraluminal blood pressure due to an acute distal trombus. This sign has high specificity but with poor sensibility. It may also seen in the presence of a high hematocrit level or MCA calcification but in both are usually bilateral.

b.

Picture (b.) shows loss of differentiation of white and gray matter in the right insular lobe. There is also associated effacement of sulci and diffuse hypodensity. This is called the "insular ribbon sign". Also a sign seen in acute infarcts.

c.

As it shows in (c.) there is a hipodensity or attenuation of right lenticulostriate nucleus with loss of differentiation of gray and white matter that extends to cortical and subcortical regions of temporal lobe with involment of sulci and gyri due to subtle citotoxic edema.

This are all early CT signs of acute ischemia in the territory of  right MCA. But as the signs are barley noticeable, they asked for a more specific diagnostic tool, so I suggested a DWI sequence on MR. Neurosurgeon agreed.

DWI as I explained in a commentary on an article posted some weeks ago, has a high sensitivity to acute and hyperacute brain ischemia because shows restricted diffusion to water particles in areas where there is no blood perfusion and it's manifested with a high intensity signal.

Here is the comparison between CT and DWI. As you see, DWI is more elocuent.

So, early ischemic CT signs can be useful when there is no MR, or when antithrombotic therapy has to be introduced as quick as possible. It needs a bit of a detailed image analysis and a good correlation with clinical data. Remember, time is brain.


Here are some great articles that can be helpful:








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