Wk 1, Case 3 - Review

CT PERFUSION STROKE PROTOCOL W/WO IV CONTRAST, CTA NECK W/WO IV CONTRAST

INDICATION: stroke, word finding difficulties, confused, expressive aphasia
TECHNIQUE: Multiple-row detector helical CT examination of the head without intravenous contrast. Postintravenous contrast images were obtained through the head per standard CTA/CT Perfusion protocol. Multiplanar reformatted, MIP, and volume rendered images were generated from the CT dataset.
COMPARISON: None available
FINDINGS:
CT HEAD WITHOUT CONTRAST:
Loss of gray-white differentiation with focal low-attenuation in the left insular cortex, left frontal operculum with additional involvement of the left putamen and external capsule compatible with a left MCA infarct. No CT evidence for acute intracranial hemorrhage. Remainder of the gray-white differentiation is grossly preserved.
Orbital contents are unremarkable. Paranasal sinuses are clear. Calvarium is intact. There is a small osteoma of the inner table of the right frontal bone. No mastoid effusions.

CT PERFUSION: Rapid CT perfusion software demonstrates a focal area of decreased cerebral blood volume with slightly greater area of time to maximum within the left frontal lobe and insular cortex corresponding to the acute infarct. Reported mismatch
volume is 2 mL with Tmax greater than 6 seconds volume of 6 cc and CBF less than 30% volume of 4 cc.

The Siemens perfusion imaging demonstrates slightly greater elevated time to maximum, mean transit time and time to drain within the left anterior corona radiata that does not demonstrate decreased cerebral blood volume which may indicate at risk ischemic tissue. Otherwise a relatively matched defect is seen. Remainder of the vascular territories demonstrate symmetric perfusion.

CTA:
Severe 4 mm short segment critical narrowing of a proximal left M2 anterior branch (Key Image 2).

There appears to be robust opacification distally of this segment with relative symmetric vascularity within the MCA branches bilaterally. There is also occlusion of one superiorly oriented early sylvian branch seen best on Key Image 3.


As seen best on Key Image 4 there is a clot identified in the upward vertically oriented sylvian segment of one anterior left middle cerebral artery branch. A more medial branch shows gradual tapering.



Slightly smaller caliber of the left petro cavernous ICA compared to the contralateral side. There is early venous filling within the right cavernous sinus which slightly limits evaluation.

Trifurcated anterior cerebral artery anatomical variation. The vessels appear widely patent. The right MCA branches are patent. The bilateral posterior cerebral arteries as well as the basilar artery and intracranial vertebral arteries are patent. No significant flow-limiting stenosis or aneurysm is seen.

There is a very subtle luminal irregularity left distal cervical ICA. The bilateral common carotid and cervical internal carotid arteries are otherwise widely patent. The extracranial vertebral arteries are patent. Suboptimal evaluation at the origin of the left T1 segment from venous contamination.

NON-VASCULAR:
Enhancing 1.2 x 1.0 cm exophytic right thyroid gland nodule posteriorly. Visualized lung apices are clear. Remainder of the soft tissues of the head and neck are normal. Osseous structures are intact.


IMPRESSION:

Loss of gray-white differentiation and focal attenuation in the left insular cortex and left frontal operculum compatible with acute left MCA infarct. Critical narrowing short segment narrowing of a proximal left M2 branch with robust opacification distally and symmetric MCA vascularity. In addition there is a focal area of nonopacification in one anterior left sylvian branch measuring 5.5 mm compatible with a thrombus. A more medial and anterior branch shows gradual tapering suggestive of occlusion. Both of these are best seen on Key Image 4.

Rapid perfusion imaging demonstrates a relatively matched defect with a small mismatch volume = 2 mL compatible with small focal area of at risk ischemic tissue in the left anterior corona radiata on the Siemens data.

Circle of Willis and major branches are otherwise widely patent. Patent cervical carotid and intracranial vertebral arteries. Subtle luminal irregularity of the left distal cervical ICA, consider fibromuscular dysplasia.

Enhancing 1.2 cm exophytic right thyroid gland nodule. Further evaluation with ultrasound is suggested.