Case Notes
History
50 year old female presenting with acute onset left sided, weakness.Exam
Head MR Diffusion Sequences (with DWI & ADC maps)
Purpose
1. To use the diffusion maps (DWI & ADC) to identify sites of hyperacute stroke matching an arterial zone.
2. To determine whether the positive diffusion zone matches a primary stem arterial region, a secondary stem arterial region, a trunk/division arterial region, a major branch region; or a distal arterial cortical zone, or any combination;
3. In cases where there are more than one ischemic sites to determine whether changes could be from an extra cranial embolic site, or whether they represent proximal clot lysis and subsequent distal embolization;
4. To determine whether the areas involved fit best with an embolic event or embolic shower (could be from proximal plaque or cardiac source, etc;
5. To determine whether the affected areas as recognizable as a watershed zone; usually in the context of currently patent major afferent arteries (ICA’ & vertebral arteries); there are often chronic extradural carotid or vertebral occlusions;
6. To determine whether the affected area(s) could represent stroke with an end of the line watershed pattern, based on the combination of occluded major afferent brain arteries plus incomplete circle of Willis plus any additional flow-limiting stenoses;
7. Evaluate the diffusion Bo sequence for hemorrhagic conversion.
Purpose
1. To use the diffusion maps (DWI & ADC) to identify sites of hyperacute stroke matching an arterial zone.
2. To determine whether the positive diffusion zone matches a primary stem arterial region, a secondary stem arterial region, a trunk/division arterial region, a major branch region; or a distal arterial cortical zone, or any combination;
3. In cases where there are more than one ischemic sites to determine whether changes could be from an extra cranial embolic site, or whether they represent proximal clot lysis and subsequent distal embolization;
4. To determine whether the areas involved fit best with an embolic event or embolic shower (could be from proximal plaque or cardiac source, etc;
5. To determine whether the affected areas as recognizable as a watershed zone; usually in the context of currently patent major afferent arteries (ICA’ & vertebral arteries); there are often chronic extradural carotid or vertebral occlusions;
6. To determine whether the affected area(s) could represent stroke with an end of the line watershed pattern, based on the combination of occluded major afferent brain arteries plus incomplete circle of Willis plus any additional flow-limiting stenoses;
7. Evaluate the diffusion Bo sequence for hemorrhagic conversion.
Prior Study
CTA Final Impression1. There is dense calcification in the Rt. high cervical ICA on the noncontrast CT, which is the likely nidus precipitating the thrombotic occlusion of the Rt. cervical ICA.
2. There are moderate, non flow-limiting stenosis of both EAC & IAC origins in the 50% range. These could contribute to reduced Rt. cerebral perfusion pressure given there is also an incomplete circle of Willis.
3. Rt. cervical IAC occlusion beginning just beyond carotid sinus with evidence of soft clot in the lumen. The thrombus continues up to the posterior genu of the intracranial-extradural ICA segment. Both the proximal or distal ends of the thrombus are potential sources for secondary embolization.
4. Minimal evidence of post ischemic arteriopathy with subtle intraluminal irregularities, minimal filling delay, and subtle loss of BBB. Findings are consistent with recanalization after recent thromboembolic event.
5. EC-IC collateral provided by ascending pharyngeal-cavernous sinus EC-IC connection; this delays arterial filling on the right but all distal arteries are patent.
6. The post ischemic arteriopathy in the second M3 branch could affect the right premotor area, which would account for the symptoms of left sided transient weakness.
7. There is no pial collateral gap nor evidence of reduced venocapillary CT density to confirm completed infarction in the areas of dysautoregulation.