Hyperacute Arterial Stroke: MR Diffusion

History

Acute change in neurologic status; rule out stroke.

Exam

Head MR Sequences (FLAIR & Diffusion with DWI & ADC maps) in this case the MR was obtained 6.5 hours after embolectomy and with new symptoms.

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 B-zero sequence for hemorrhagic conversion.

Prior Study

CT Head

CTA Final Impression

Findings

Evaluate for evidence of hyper acute ischemic brain event on DWI/ADC

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable ACA (all or parts of) cortical arterial territory. [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable MCA (all or parts of) (including anterior temporal polar or lateral orbitofrontal branch) cortical arterial territories. [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable PCA (all or parts of) cortical arterial territory. [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable SCA (all or parts of) cortical arterial territory. [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable AICA or PICA (all or parts of)) cortical arterial territory. [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable anterior choroidal cortical arterial territory. [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable cirummesencephalic cortical arterial territory. [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable mesial lenticulostriate perforator arterial territory. [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable lateral lenticulostriate perforator arterial territory. [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable basilar tip perforator arterial territory (to mesial thalamus). [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable P1/P2 perforator arterial territory (to include P1 perforators to the posterior thalamus/lateral thalamus/ thalamogeniculate nuclei or posterior mesial choroidal or posterior lateral choroidal perforators to the dorsal thalamus). [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable basilar artery perforator arterial territory (to central aspects of brain stem). [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable SCA or AICA or PICA penetrating arterial territory (to outer portion of the brain stem and the dorsal aspect of the mesencephalon/medulla). [Yes/No]

There is abnormal diffusion imaging (both DWI & ADC maps) within a recognizable arterial watershed territory either the usual type or the shifted end of the line type. [Yes/No]

There is diffusion positivity encompassing the entire expected territory for the affected artery. [Yes/No]

There is diffusion positivity encompassing less than the expected territory for the affected artery. [Yes/No]

There is diffusion positivity encompassing more than the expected territory for the affected artery. [Yes/No]

There is diffusion positivity involving only the terminal arterial branches (indicating embolic disease is likely). [Yes/No]

There is more than one distal arterial stroke of the same age, but in seperate arteries (primary embolic event). [Yes/No]

There is more than one stroke in the same vessel distribution (clot lysis with distal secondary embolization with possibly different ages). [Yes/No]

Evaluate for evidence acute sequestration within the ischemic event (implying no effective pial collateral, no afferent artery recanalization and no transcapillary blood flow). This usually appears as positive DWI only on margins of stroke zone, while the affected area is positive on ADC map. [Yes/No]

There is evidence of intercurrent reperfusion hemorrhage. [Yes/No]