Loss of insular ribbon sign

Case contributed by A/Professor Christen Barras

Presentation

Acute onset left hemiparesis, sub-3 hours post ictus.

Patient Data

Age: 85
Gender: Female
CT

CT Brain

Noncontrast images were obtained. Despite this patient's sub 3 hour presentation following symptom onset, known renal failure precluded CTP/CTA.

Loss of right insular cortical grey-white matter differentiation (insular ribbon) in keeping with acute ischemia within the territory of the right middle cerebral artery. No hyperdense MCA or sub-branch thereof is identified. Basal ganglia delimitation is preserved. No intracranial haemorrhage. No hydrocephalus or midline shift.

Elsewhere, extensive periventricular and deep white matter hypoattenuation is consistent with advanced chronic small vessel ischaemic change.

Incidental note made of bilateral cavernous ICA calcification. Dense calvarium, without evidence of fracture or focal suspicious abnormality.

Conclusion:

Loss of right insular cortical grey-white matter differentiation (insular ribbon) in keeping with acute right MCA territory infarct.

Findings discussed with Stroke team at time of scanning.

MRI

MRI Brain: DWI/ADC

MRI Brain:

DWI sequence with ADC calculation was performed, as a limited post-stroke examination. Correlation is made with CT brain which identified hyperacute right MCA territory ischemia.

Serpiginous right insular cortical diffusion restriction with ADC depression, consistent with acute ischemia, and correlating with clinical signs and CT appearance. In addition, multiple foci of diffusion restriction extend multifocally over cortical frontoparietal gyri, all within right middle cerebral artery territory.

Conclusion:

Multifocal cortical right MCA territory infarction, most prominently involving the right insular cortex, corresponding to CT appearance and clinical signs.

Case Discussion

This case illustrates a common and sometimes subtle finding on CT for stroke protocol: the loss of the insular ribbon

The insular cortex is more susceptible to ischaemia following MCA occlusion than other portions of the MCA territory because it has the least potential for collateral supply from the anterior cerebral and posterior cerebral arteries.

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Case information

rID: 33961
Case created: 30th Jan 2015
Last edited: 11th Mar 2017
Inclusion in quiz mode: Included

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