Case Notes
History
79 year old female with sudden onset symptoms including Rt. facial droop, Rt. side weakness; the patient was nonverbal nor following commands; there is known history of secondary diabetes with hyperlipidemia.Exam
CTA of the Head: this part of the stroke protocol CTA is performed after the 1st bolus of contrast and is referred to as the initial post contrast head CTA exam. Since there is no recirculation of contrast, it has the advantage of identifying stenoses and short segment occlusions without obscuration by pial collateral. On the other hand, it may underfilling patent, more distal, arteries, which, of course, also reduces the CT-density in the venocapillary pool within brain parenchyma. Thus, the initial post contrast head CTA tends to overestimate the depth of injury in the apparent stroke-zone.
Purpose
1. To define sites of afferent supratentorial arterial thrombosis or flow-limiting high-grade stenosis or lesser but tandem stenoses, or stenosis plus incomplete circle of Willis with isolated arterial circuit;
2. To define sites of afferent infratentorial arterial thrombosis or flow-limiting high-grade stenosis;
3. To determine features of vessel wall and intimal status;
4. To assess presence of tandem stenosis or stenosis plus incompetent circle of Willis;
5. In case of ICA stenosis/occlusion is there effective EC-IC collateral;
6. Is there a watershed stroke zone affecting the usual anastomotic arterial boundary zones;
7. in case of afferent primary stem arterial block (occlusion or high-grade stenosis) combined with an incomplete circle of Willis, is there a shift of the expected watershed zone changing the usual end-of the-line pattern of oligemia to an unexpected position (i.e. a “shifted watershed zone”); V10.
8. To assess status of retrograde pial collateral and asses for any pial collateral gap between proximal thrombus & retrograde pial collateral;
9. To assess for delayed venous egress (need to prove on post contrast CT head whether it is just delayed or is actually persistently reduced or absent).
Purpose
1. To define sites of afferent supratentorial arterial thrombosis or flow-limiting high-grade stenosis or lesser but tandem stenoses, or stenosis plus incomplete circle of Willis with isolated arterial circuit;
2. To define sites of afferent infratentorial arterial thrombosis or flow-limiting high-grade stenosis;
3. To determine features of vessel wall and intimal status;
4. To assess presence of tandem stenosis or stenosis plus incompetent circle of Willis;
5. In case of ICA stenosis/occlusion is there effective EC-IC collateral;
6. Is there a watershed stroke zone affecting the usual anastomotic arterial boundary zones;
7. in case of afferent primary stem arterial block (occlusion or high-grade stenosis) combined with an incomplete circle of Willis, is there a shift of the expected watershed zone changing the usual end-of the-line pattern of oligemia to an unexpected position (i.e. a “shifted watershed zone”); V10.
8. To assess status of retrograde pial collateral and asses for any pial collateral gap between proximal thrombus & retrograde pial collateral;
9. To assess for delayed venous egress (need to prove on post contrast CT head whether it is just delayed or is actually persistently reduced or absent).
Prior Study
CT Head1. Acute thrombus is present in the proximal Lt. M1 & M2 segments of the MCA.
2. Early stroke findings are evident in the rostral portions of the Lt. lateral lenticulostriate perforator, the Lt. orbitofrontal, and the Lt. MCA arterial perfusion zones.
3. The stroke timeline in all the affected areas are similar, and all are likely to have occurred within the stroke treatment window.
CT Perfusion
1. There is prolongation of the TTP & reduced CBV/CBF in the superior division Lt. MCA are consistent with post ischemic parenchymal injury. There is focal, marked, reduction (likely within the dense ischemic core) within the perfusion zones of the Lt. lateral lenticulostriate perforators and the rostral left M3 anterior insular territory. There is post ischemic change likely affecting white matter deep to Broca’s area, premotor cortex and primary motor cortex (especially in facial portion). These areas of involvement appear to match the included clinical symptoms.
2. There is partial reduction of CBV and CBF are evident in the lateral orbitofrontal artery territory and in the lateral cortex (superior division MCA) imply ischemic penumbra, but is protected to some degree by pial collateralization.
CTA Neck
1. Rt. proximal ICA stenosis in the 50-60% range, but on side opposite the stroke. This stenosis plus hypoplastic P-coms are likely to reduce circle of Willis collateral availability to the Lt MCA region, especially in the context of a known hyperacute Lt M1/2 thrombosis.
2. Suspicious nodule in the left thyroid.