Brain

Discussion

47-year-old female with a history of right middle cerebral artery (MCA, M1) stenosis and multiple stroke episodes was treated with IV thrombolysis and thrombectomy for another stroke episode in right MCA territory. Evaluation with spectral CT 24 hours later.

Differentiation of intracranial hemorrhage from contrast extravasation/staining after thrombectomy in acute stroke patients.

Axial images

Follow-up CT without contrast 24 hours after IV thrombolysis and thrombectomy demonstrated hyperdensity within right sylvian fissure and right-sided sulcal hyperdensities. Persistence of right sylvian fissure hyperdensity on virtual non-contrast images and lack of demonstration of iodine on iodine overlay images suggested hemorrhage rather than contrast extravasation in right sylvian fissure. Contrarily, right-sided sulcal hyperdensities were not visible on virtual non-contrast images, and iodine overlay images demonstrated iodine content in this area suggesting extravasated contrast rather than hemorrhage. These findings suggested a mixture of hemorrhage and contrast extravasation. Follow-up MRI FLAIR images 3 days later demonstrated persisting hyperintensity within right sylvian fissure confirming hemorrhage and lack of right sulcal hyperintensities confirmed early washout of extravasated contrast media.

On follow-up CT images of stroke patients after thrombectomy, hyperdensities caused by intracranial hemorrhage or contrast extravasation could be difficult to differentiate. Spectral CT could allow distinguishing intracranial hemorrhage from contrast staining with virtual non-contrast and iodine overlay images. This might eliminate the need for waiting for follow-up imaging to make the differentiation.

Conventional CT axial image: hyperdensity in the right sylvian fissure (arrow).

Virtual non-contrast axial image: demonstration of hyperdensity (arrow) on virtual non-contrast images suggesting hemorrhage rather than contrast extravasation.

Iodine overlay axial image: lack of increased iodine content (arrow) in right sylvian fissure suggesting hemorrhage rather than contrast extravasation.

Conventional CT axial image: sulcal hyperdensity in right frontal region (arrow).

Virtual non-contrast axial image: lack of corresponding sulcal hyperdensity (arrow) on virtual non-contrast images suggesting contrast extravasation.

Iodine overlay axial image: demonstration of corresponding sulcal iodine content (arrow) suggesting contrast extravasation rather than hemorrhage.

Follow-up MRI 3 days later, axial FLAIR images: (a) persisting hyperintensity (arrow) within right sylvian fissure corresponding to hemorrhage. (b) Absence of sulcal hyperintensities confirming washout of contrast media.

History Benefits or pitfalls of dual-energy CT