Case Notes
History
72 year old male with transient left sided weakness; history of diffuse vascular disease; evaluate for arterial stenosis.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
Non-Contrast Head CTThere is a probable left high-cervical ICA acute intraluminal thrombus.
There are expected age related changes and a chronic post-ischemic lacunar infarct in the mesial Lt. thalamus.
No hyperacute post ischemic changes are evident.
CT Perfusion
There are changes consistent with Lt. ICA afferent obstruction (occlusion or high-grade stenosis) which slows the left hemispheric blood flow but has not significantly reduced in the CBV or CBF in either the left ACA or MCA or mesial P4 perfusion zones.
There is reduced perfusion in the left MCA-PCA watershed zone with reduced CBV/CBF/MTT.
There is delayed filling rate in the Lt. PICA perfusion zone, but the increased CBV indicates there is functional pial collateralization.