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Absent middle cerebral artery flow predicts the presence and evolution of the ischemic penumbra
P A Barber1, S M Davis, D G Darby
1Department of Neurology, The Royal Melbourne Hospital, Parkville, Vic, Australia.
Objectives:
In acute ischemic stroke the pattern of a perfusion-imaging (PI) lesion larger than the diffusion-weighted imaging (DWI) lesion may be a marker of the ischemic penumbra. We hypothesized that acute middle cerebral artery (MCA) occlusion would predict the presence of presumed "penumbral" patterns (PI > DWI), ischemic core evolution, and stroke outcome.
Methods:
Echoplanar PI, DWI, and magnetic resonance angiography (MRA) were performed in 26 patients with MCA territory stroke. Imaging and clinical studies (Canadian Neurological Scale, Barthel Index, and Rankin Scale) were performed within 24 hours of onset and repeated at days 4 and 90.
Results:
MCA flow was absent in 9 of 26 patients. This was associated with larger acute PI and DWI lesions, greater PI/DWI mismatch, early DWI lesion expansion, larger final infarct size, worse clinical outcome (p < 0.01) and provided independent prognostic information (multiple linear regression analysis, p < 0.05). Acute penumbral patterns were present in 14 of 26 patients. Most of these patients (9 of 14) had no MCA flow, whereas all nonpenumbral patients (PI < or = DWI lesion) had MCA flow (p < 0.001). Penumbral-pattern patients with absent MCA flow had greater DWI lesion expansion (p < 0.05) and worse clinical outcome (Rankin Scale score, p < 0.05).
Conclusions:
Absent MCA flow on MRA predicts the presence of a presumed penumbral pattern on acute PI and DWI and worse stroke outcome. Combined MRA, PI, and DWI can identify individual patients at risk of ischemic core progression and the potential to respond to thrombolytic therapy beyond 3 hours.
Insights
Absent middle cerebral artery (MCA) flow on magnetic resonance angiography (MRA) indicates a larger perfusion-imaging (PI) lesion than diffusion-weighted imaging (DWI) lesion, predicting worse stroke outcomes and potential for progression. This imaging combination aids in identifying patients who may benefit from acute stroke therapies.
Area of Science:
- Neurology
- Radiology
- Stroke Medicine
Background:
- The ischemic penumbra, a region of potentially salvageable brain tissue, is crucial in acute ischemic stroke management.
- Perfusion-imaging (PI) lesion size exceeding diffusion-weighted imaging (DWI) lesion size may indicate the presence of a penumbra.
- Middle cerebral artery (MCA) occlusion is a common cause of acute ischemic stroke.
Purpose of the Study:
- To investigate if absent MCA flow on magnetic resonance angiography (MRA) predicts penumbral patterns (PI > DWI).
- To determine if absent MCA flow predicts ischemic core evolution and stroke outcome.
- To assess the prognostic value of combined MRA, PI, and DWI in acute MCA stroke.
Main Methods:
- Echoplanar PI, DWI, and MRA were performed in 26 patients with MCA territory stroke.
- Clinical assessments (Canadian Neurological Scale, Barthel Index, Rankin Scale) were conducted at baseline, day 4, and day 90.
- Statistical analyses, including multiple linear regression, were used to evaluate associations.
Main Results:
- Absent MCA flow was observed in 9 of 26 patients, correlating with larger PI and DWI lesions, greater PI/DWI mismatch, and early DWI lesion expansion.
- Patients with absent MCA flow experienced larger final infarcts and worse clinical outcomes (p < 0.01).
- Penumbral patterns (PI > DWI) were present in 14 patients, predominantly those with absent MCA flow (9 of 14).
Conclusions:
- Absent MCA flow on MRA is a strong predictor of presumed penumbral patterns and adverse stroke outcomes.
- Combined MRA, PI, and DWI can identify patients at risk of ischemic core progression.
- This imaging approach may help select patients for thrombolytic therapy, even beyond the 3-hour window.