Post contrast head CT
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As a result of participation in this activity, participants should be able to:
- Provide improved patient care.
- Greater knowledge of the imaging characteristics of the patient's disease.
- Understand a better approach to interpretation of studies.
Faculty Disclosure
Mehmet Albayram, MD, Ivan Davis, MD, Mariam Hanna, MD, Anthony Mancuso, MD, Ronald Quisling, MD, Dhanashree Rajderkar, MD, Priya Sharma, MD, Roberta Slater, MD and Joann Stamm, MBA have disclosed that they have no relevant financial relationships. No one else is a position to control content have any financial relationship to disclose.
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Conflict of interest information for the CME Advisory Committee members can be found on the following website: https://cme.ufl.edu/disclosure/.
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CA0386-Post contrast head CT
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CA0386-Post contrast head CT
Case ReportExam
Prior Study
1. Hyperacute very focal intraluminal thrombus in a single mid insular M3 branch off the superior division Lt. MCA; stroke-age would likely be hyperacute.
CT Perfusion
1. Focal area of minimally reduced CBV and CT density within the venocapillary pool in the mid left insula. This matches the territory of the acute branch thrombus on the noncontrast head CT.
2. The wider area of both prolonged TTP/MTT (compared to the CT) suggests that there is additional thrombus in the more proximal M3 trunk that is not currently hyperdense on CT.
CTA of the Neck
Negative CTA of the neck without evidence of a source for left cerebral embolization.
CTA of the Head (using initial post contrast exam)
1. There is partial occlusion of the posterior trunk superior MCA division (non hyperdense) resulting in slower filling of arteries to the the posterior insula and distal M4 branches in the parietal and retrosylvian cortex. This matches the prolonged TTP/MTT and the hyperemic response to slow flow on the CT perfusion.
2. There is a single hyperdense artery to the central sulcus, which is hyperdense and does not fill in its’ initial segment. Retrograde pial collateral fills the distal part of this artery leaving a 1cm. area of pial collateral gap. This oligemic area includes the mid insula and adjacent intrasylvian cortex which corresponds to the lower motor cortex including the tongue region, which in this patient has produced dysarthria.
3. Since CTA reveals a more proximal non hyperdense segment of thrombus in the posterior superior division trunk, it is possible that the hyperacute (hyperdense) single arterial thrombus may be the result of clot lysis and secondary embolization.
Findings
Post contrast head CT for venocapillary pool analysis
The delayed CTA demonstrates better filling of all posterior trunk superior division branches leaving only a small pial collateral gap in the mid insula and possibly the adjacent intrasylvian operculum. There is dilatation of the arteries in the posterior superior division trunk and there is some leak of contrast in the high convexity MCA perfusion zone. These findings are likely related to post ischemic arteriopathy and dysautoregulation.
Likewise, the CT density within the venocapillary pool is normal in most of the affected area (of prolonged TTP), except for a small area of persistently reduced parenchymal venocapillary pool density in the mid insula, which of course is the lower extent of the motor cortex. Based on the patients’ symptom of dysarthria, we know the ischemic area likely includes the tongue part of the motor cortex.
Cerebral venous egress is within normal limits
Impression
2. The CT density in the venocapillary pool on the delayed CTA is slightly increased above normal and there is minimal arterial dilatation in most of the distribution of the arteries included in the posterior trunk of the left MCA. Since there is also some contrast leak the findings are consistent with post ischemic dysautoregulation. This perfusion zone is included in the area of slow flow on the TTP (CT perfusion) as well; nevertheless it indicates good collateralization in all areas except the insular part of the artery to the central sulcus perfusion zone.
3. The occlusion of the proximal part of the artery to the central sulcus has partial pial collateral leaving an area of persistent small pial collateral gap and focal area of reduced CT density in the venocapillary pool in the mid-insula and adjacent intrasylvian operculum. This area has persistent oligemia and is a likely site of stroke, but depth and duration of the ischemic event is indeterminate. The affected area does include the tongue primary motor areas accounting for the dysarthria symptom.
4. Negative neck CTA for any embolic source.
Recommendations
Consider MR to evaluate for tissue ischemia that is not revealed on the CT perfusion or CT venocapillary pool and to evaluate status of intramedullary veins
