Case Notes
History
76 year old male presenting with acute slurred speech, left sided weakness, and left facial droop.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 arterial block, plus an incomplete circle of Willis, is there a potential end-of the-line type of watershed stroke;
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 arterial block, plus an incomplete circle of Willis, is there a potential end-of the-line type of watershed stroke;
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. Hyperacute thrombus in M1 and M2 segments of the Rt. MCA
2. The post-ischemic stroke changes affect the Rt. orbitofrontal artery, the rostral lateral lenticulate perforators, and the anterior portion of the intrasylvian MCA superior-division branch perfusion zones; these involved areas are likely beyond the IV treatment window.
3. The posterior M3 sylvian arterial perfusions zone may have some post ischemic changes, but likely are at least partially spared by pial collateral. The same is true for most of the lateral cortex.
CT Perfusion
CT perfusion evidence of prolonged filling rate (prolonged TTP/MTT) affecting mainly the Rt. lateral orbitofrontal perfusion zone with lesser post ischemic changes in the Rt. lateral basal ganglia (lateral lenticulostriate perforator perfusion zone) and the anterior insular M3 perfusion zones. However, the CBV is only minimally reduced in most areas and is only partially reduced in the right orbitofrontal artery perfusion zone indicating at least reasonable retrograde pial collateralization in most of the area included in the prolonged TTP zone.
CTA Neck
1. Abnormal Rt. cervical carotid with 70% stenosis at carotid bifurcation/proximal ICA area with distal luminal partial collapse. The Rt. ICA lumen becomes very small after the calcified nodular plaque at the posterior genu, and finally terminates before the subclinoidal segment. The Rt. ICA lumen is reconstituted just after the dural ring.
2. Other major cervical arteries have age-related changes without flow-limiting stenoses.