Hyperacute Venous Stroke: CT Venocapillary Analysis

History

Recent neurologic changes, often not focal.

Exam

Post contrast CT for analysis of CT density in the venocapillary pool

CTA may be the exam obtained instead of CTV. In this case the CT perfusion, the head and neck CTA's are all obtained in the arterial phase. However, the 2 minute delayed post contrast CT will have venous data and can be used for venous evaluation. It won't however, be available with subtraction.

CVT (in our protocol) of the head (and usually the neck) are obtained after a single bolus of contrast where the timing of image acquisition is delayed to emphasize venous opacification. The post contrast CVT is equivalent to the 2 minute delayed post contrast head CT done during CTA exams. Both exams assess tissue level perfusion based on the CT density within theparenchymal venocapillary pool. The one problem with CTV is the inherently prolonged time interval between acquisition of the noncontrast images (used for subtraction) and the venous phase is longer increasing the potential of patient motion degrading the subtracted images.

Purpose

1. To identify any site of reduced CT density in any area of the venocapillary pool to confirm site of significant oligemia.

2. To determine if there is opacification of the dural sinuses indicating patency. Note: luminal thrombosis is only confirmed when the dural sinus is viewed in cross-section. Thus, nearly always need to apply multiplanar reformations. Also note, the sites of luminal thrombosis are often segmental in different sites within different sinuses. These segmental dural thrombosis are bridged by dural sinus wall and venous lacunae collaterals. Hence, the next purpose #3.

3. To identify evidence of opacification of the dural sinus wall plus lack of luminal opacification to dural wall collateralization. Dural wall collateral typically enlarges the overall size of the dural sinus.

4. To determine the state of venous egress (i.e. pattern of how the blood gets out of the head) has been altered, or even reversed in direction.

5. To identify pial venous collateral veins, which usually increase size, characteristic serpiginous appearance, and altered filling pattern (they drain toward unexpected major vein sites). Flow direction is often reversed (vein gets larger at its’s source rather than when it approaches a dural sinus.

6. Identify sites of intraluminal thrombus, which will correspond to the vein course.

7. Idenitfy sites of hemorrhagic conversion, which usually eminate from the junction of the vein thrombus with the pial venous collateral (corresponding to the site of venous reperfusion).

Prior Study

CT Head
CT Perfusion
CTA/MRA Neck and/or Head

Findings

CTA Venocapillary Analysis

The delayed post contrast head CT demonstrates exaggerated (increased) CT density within venocapillary pool compared to the contralateral side, reflecting vasodilatation. [Yes/No]

The delayed post contrast head CT demonstrates significantly reduced CT density within the venocapillary pool in the affected area consistent with venous infarction. [Yes/No]

The delayed post contrast head CT demonstrates evidence of intraluminal filling defects, or evidence of venous congestion, or venous collateral with tortuosity and reversal of drainage pattern. [Yes/No]

There is leak of constrast consistent with loss of blood brain barrier (BBB). [Yes/No]

There is prominence of any of the pial/dural anastomotic sites (i.e. vertex venous lacunae, tenorial confluences, or cavernous sinus/retropharyngeal venous plexus). [Yes/No]