Hyperacute Transcapillary Stroke III - Clinical Case Summary
Hyperacute Transcapillary Stroke III - Clinical Case Summary
Hyperacute Transcapillary Stroke III - Clinical Case Summary
SummaryHistory
43 yo female presenting with acute neurological decline following bronchoscopy w/ cryotherapy for sarcomtous mets; presumed inadvertent IV air embolization.
Exams performed
CT Head; T1-w MR pre contrast; MR diffusion; MR T2-w and MR flair
Prior available imaging reports
Noncontrast CT Head
1. Acute cytogenic edema involving the right anastomotic ACA-MCA border zone affecting both the overlying cortex as well as the subcortical white matter. Given the clinical context findings are likely related to CNS air embolization.
T1-w MR pre contrast only
1.Acute cytogenic edema involving the right anastomotic ACA-MCA border zone which includes the ACA-MCA cortex, as well as the subcortical white matter ACA-MCA watershed zone. Given the clinical context findings are likely related to CNS air embolization. Findings are similar to the noncontrast CT head without interval change.
MR diffusion Bo, ADC and DWI sequences
1. Findings are consistent with air microembolization, which affects the cortex more than the underlying white matter. Abnormalities affect the ACA-MCA anastomotic border bilaterally but more on the right than the left. The involvement of the cortex more than the white matter is consistent with stroke at the metarteriole-transcapillary level, which is consistent with CNS microembolization.
MR T2-w and MR flair sequences
1. The overall ischemic effects from microembolization of air has affected the cortex more than the white matter and extended downward along the Virchow-Robin spaces, which are features of a transcapillary type of stroke.
1. Acute cytogenic edema involving the right anastomotic ACA-MCA border zone affecting both the overlying cortex as well as the subcortical white matter. Given the clinical context findings are likely related to CNS air embolization.
T1-w MR pre contrast only
1.Acute cytogenic edema involving the right anastomotic ACA-MCA border zone which includes the ACA-MCA cortex, as well as the subcortical white matter ACA-MCA watershed zone. Given the clinical context findings are likely related to CNS air embolization. Findings are similar to the noncontrast CT head without interval change.
MR diffusion Bo, ADC and DWI sequences
1. Findings are consistent with air microembolization, which affects the cortex more than the underlying white matter. Abnormalities affect the ACA-MCA anastomotic border bilaterally but more on the right than the left. The involvement of the cortex more than the white matter is consistent with stroke at the metarteriole-transcapillary level, which is consistent with CNS microembolization.
MR T2-w and MR flair sequences
1. The overall ischemic effects from microembolization of air has affected the cortex more than the white matter and extended downward along the Virchow-Robin spaces, which are features of a transcapillary type of stroke.
Overall impression
1. Acute post-ischemic cytogenic edema localized to the right ACA-MCA anastomotic border zone with lesser ischemic changes in the left ACA-MCA perfusion zone. The ischemic changes are of the same age and involve cortical branches and the distal penetrating end-arteries more on the left than right. Findings are consistent with an embolic shower. Because of the history of recent bronchoscopy and cryosurgery, air embolization was suspected.
Lessons to be learned
1. Microembolization which is seen with IV air embolization, as in this case, nitrogen narcosis (the bends) from diving accidents, small emboli passing throught an incompetent atrial septal defect, and fat embolization from surgery of traumatic fractures reach the metarteriole-capillary bed junction. As a result they have exhibit features of transcapillary stroke rather than a recognizable arterial or venous stroke.
2. Microembolization causes ischemic end-artery changes similar to those of the primary and secondary CNS angiitis and sludging disorders like sickle cell disease (covered in the Pediatric stroke Module). The features include: 1. multicentric strokes of differing ages, 2. cortical involvement more than subcortical involvement, 3. when there is subcortical involvement in exhibits a pattern which follows the Virchow-Robin space, 4. multicentric small end-artery strokes can be punctate and often appear as cortical laminar necrosis.
3. Subtle cytogenic post ischemic edema is best imaged on MR flair. Not all sites of edema will necessarily be currently MR diffusion positive.
4. The Bo sequence in MR diffusion must be viewed first to see if there is subacute cytogenic, which will show as positive on the MR DWI. The MR DWI is positive for both hyperacute and acute cytogenic ischemic injury. The MR ADC map can separate what part of the diffusion signal is hyperacute by being positive on both the DWI and ADC maps and negative on the Bo sequence.
2. Microembolization causes ischemic end-artery changes similar to those of the primary and secondary CNS angiitis and sludging disorders like sickle cell disease (covered in the Pediatric stroke Module). The features include: 1. multicentric strokes of differing ages, 2. cortical involvement more than subcortical involvement, 3. when there is subcortical involvement in exhibits a pattern which follows the Virchow-Robin space, 4. multicentric small end-artery strokes can be punctate and often appear as cortical laminar necrosis.
3. Subtle cytogenic post ischemic edema is best imaged on MR flair. Not all sites of edema will necessarily be currently MR diffusion positive.
4. The Bo sequence in MR diffusion must be viewed first to see if there is subacute cytogenic, which will show as positive on the MR DWI. The MR DWI is positive for both hyperacute and acute cytogenic ischemic injury. The MR ADC map can separate what part of the diffusion signal is hyperacute by being positive on both the DWI and ADC maps and negative on the Bo sequence.
Recommendations
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