Case Notes
History
51 year old female presenting with an acute left facial droop, left side weakness, and mental status change. Patient was able to be seen in the ER within 1 to 1.5 hours after the onset of symptoms.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”);
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).
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”);
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 HeadRt. parapharyngeal space is abnormal with enlarged high cervical ICA with hyperdensity consistent with an acute high cervical ICA dissection.
Apparent recent, but not hyperacute Rt. parietal subcortical ischemic event.
CT Perfusion
Reduced arterial circulation rate in the Rt. cerebral intradural ICA watershed perfusion zone in the usual centrum semiovale. There is evidence of good pial collateral resulting in normal cortical CBV. Distinct site of actual infarction (low CBV) is not detected. The right ICA dissection was evident on the included post contrast head CTA.
CTA of the Neck
There is a relatively long segment dissection of the Rt. ICA. The mural thrombus is hypodense consistent with recent thrombotic event. The length of the mural lesion is consistent with dissection rather than atherosclerotic or inflammatory causes of stenosis. There is luminal irregularity, but no clear intimal dehiscence nor pseudoaneurysm at this time.
The dissection produces a high-grade stenosis at the vertical segment of the petrous carotid segment. There is persistent antegrade blood Q, but the the ICA is partially collapsed indicative of significant Q limiting stenosis.
The circle of Willis is incomplete with hypoplastic P-com’s.
There are early changes of FMD affecting the left high cervical ICA.