Case Notes
History
59 year old male with COPD who developed tachycardia requiring therapy. Two days later he developed Rt. sided weakness, pupillary dysfunction, and slurred speech. Shortly thereafter, he became somnolent and unresponsive.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 basilar and left intradural vertebral artery thromboses with multicentric both arterial and watershed strokes involving multiple posterior fossa arteries, as described above.
2. There is early mass effect including compression of the 4th ventricle, effacement of prepontine cisterns, and clear evidence of early upward transtentorial herniation.
3. Focal lesion within the deep central left cerebellum is likely a site of hemorrhagic conversion with very acute hematoma.
CT Perfusion
1. The TTP, CBF, & CBV changes consistent with completed infarctions in both SCA’s, the left AICA, the left PICA, the right cerebellar watershed zones, and possibly the left pons.
2. Absent MTT signal (out of scale sign) indicates virtually no transcapillary blood flow to generate MTT data. This is can occur with either sequestered infarction, or hemorrhagic transformation, or both. Differentiation between these two stroke complications is best exhibited on the MR susceptibility sequence.
3. CTA head (included with our CT perfusion protocol) demonstrates patency of the left intradural vertebral artery and of the caudal basilar artery at this time, despite the CT-hyperdensity seen on the noncontrast CT head .
4. There is an old infarct with an encephalomalacic defect in the left temporal lobe (PCA-P3 segment perfusion zone).
CT Neck
1. Diffuse atherosclerotic vascular disease is evident in the aorta with ulcerative plaque formation.
2. There is focal left ICA stenosis of 50% and a focal right ICA stenosis of 60%.
3. The proximal left vertebral artery is occluded at its’ origin, but is reconstituted at the C5 level from cervical soft tissue collaterals. The high cervical and intradural vertebral segments are within normal limits.