Case Notes
History
81 year old female presenting with acute onset mental status change, dizziness, nausea, and gait imbalance.Exam
CTA of the Neck
This part of the CTA is performed after the second bolus of contrast, and therefore has dense contrast in both the arteries and the veins related to recirculation plus twice the contrast load. The CTA neck is performed in conjunction with the delayed post contrast head CTA for assessment of the CT-density in the parenchymal venocapillary pool.
Purpose
1. Define sites of any and all arterial thromboses or flow-limiting, high-grade stenosis, or tandem stenoses with lesser degrees of luminal narrowing, but are included within the same arterial circuit;
2. Characterize the features of the stenotic/occluded arterial segment (NASCET, assess length of stenosis/occlusion, intimal dehiscence, atherosclerotic vs inflammatory basis, etc.);
3. Determine whether there is effective collateral around any occluded segment;
4. Assess the presence of effective EC-IC collateral in cases of extradural ICA occlusion.
This part of the CTA is performed after the second bolus of contrast, and therefore has dense contrast in both the arteries and the veins related to recirculation plus twice the contrast load. The CTA neck is performed in conjunction with the delayed post contrast head CTA for assessment of the CT-density in the parenchymal venocapillary pool.
Purpose
1. Define sites of any and all arterial thromboses or flow-limiting, high-grade stenosis, or tandem stenoses with lesser degrees of luminal narrowing, but are included within the same arterial circuit;
2. Characterize the features of the stenotic/occluded arterial segment (NASCET, assess length of stenosis/occlusion, intimal dehiscence, atherosclerotic vs inflammatory basis, etc.);
3. Determine whether there is effective collateral around any occluded segment;
4. Assess the presence of effective EC-IC collateral in cases of extradural ICA occlusion.
Prior Study
CT Head1. Hyperdense thrombus is evident in the distal basilar artery extending into the left P1 PCA segment.
2. Multiple recent strokes (readily apparent cytogenic edema sites) involving Lt. PICA and both P4 segments of the PCA were evident on noncontrast CT placing these ischemic events outside the hyperacute treatment timeline on the right and within the timeline on the left. There is an evolving older left PICA stroke. There is parenchymal hypdensity in the deep cerebellar watershed zones, which could be recent ischemia or chronic age-related ischemic demyelination. It is likely there has been recent thrombus in the intradural vertebral artery initially occluding the left PICA, which has then undergone clot lysis with distal secondary embolization to downstream arteries.
CT Perfusion
1. Known acute thrombus in distal basilar artery
2. Focal completed stroke is evident in Lt. PICA perfusion area and early stroke in the Lt. mesial occipital P4-PCA perfusion zone. Reperfusion (increased CBV & CBF) is evident in the Lt. occipital Ischemic zone.