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Published on: January 4, 2013
Hyperintense Acute Reperfusion Marker on FLAIR in Posterior Circulation Infarction
Alex Förster1, Holger Wenz1, Johannes Böhme1
1Department of Neuroradiology, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany.
Purpose:
In the present study, we aimed to investigate the frequency of blood brain barrier injury in posterior circulation infarction as demonstrated by the hyperintense acute reperfusion marker (HARM) on fluid attenuated inversion recovery images (FLAIR).
Methods:
From a MRI report database we identified patients with posterior circulation infarction who underwent MRI, including perfusion-weighted images (PWI), within 12 hours after onset and follow-up MRI within 24 hours and analyzed diffusion-weighted images (DWI), PWI, FLAIR, and MR angiography (MRA). On FLAIR images, the presence of HARM was noted by using pre-specified criteria (focal enhancement in the subarachnoid space and/or the ventricles).
Results:
Overall 16 patients (median age of patients 68.5 (IQR 55.5-82.75) years) with posterior circulation infarction were included. Of these, 13 (81.3%) demonstrated PCA occlusion, and 3 (18.7%) patients BA occlusion on MRA. Initial DWI demonstrated ischemic lesions in the thalamus (68.8%), splenium (18.8%), hippocampus (75%), occipital lobe (81.3%), mesencephalon (18.8%), pons (18.8%), and cerebellum (50%). On follow-up MRA recanalization was noted in 10 (62.5%) patients. On follow-up FLAIR images, HARM was observed in 8 (50%) patients. In all of these, HARM was detected remote from the acute ischemic lesion. HARM was more frequently observed in patients with vessel recanalization (p = 0.04), minor infarction growth (p = 0.01), and smaller ischemic lesions on follow-up DWI (p = 0.05).
Conclusions:
HARM is a frequent finding in posterior circulation infarction and associated with vessel recanalization, minor infarction growth as well as smaller infarction volumes in the course. Neuroradiologists should be cognizant of the fact that HARM may be present on short interval follow-up FLAIR images in patients with acute ischemic infarction who initially underwent MRI and received intravenous gadolinium-based contrast agents.
Insights
Hyperintense acute reperfusion marker (HARM) is frequently observed in posterior circulation infarction patients. This blood brain barrier injury finding on FLAIR MRI is linked to vessel recanalization and smaller infarct growth.
Area of Science:
- Neuroradiology
- Neuroimaging
- Vascular Neurology
Background:
- Posterior circulation infarction (PCI) can lead to significant neurological deficits.
- Assessing blood-brain barrier (BBB) integrity is crucial for understanding infarct evolution.
- Hyperintense acute reperfusion marker (HARM) on FLAIR MRI may indicate BBB injury.
Purpose of the Study:
- To determine the frequency of BBB injury, identified as HARM on FLAIR MRI, in patients with PCI.
- To explore the association between HARM and reperfusion markers and infarct progression.
Main Methods:
- Retrospective analysis of MRI scans (DWI, PWI, FLAIR, MRA) from patients with PCI within 12 hours of onset.
- Follow-up MRI was performed within 24 hours.
- HARM was identified on FLAIR images using pre-specified criteria for subarachnoid space and/or ventricular enhancement.
Main Results:
- 16 patients with PCI were included; 81.3% had PCA occlusion, 18.7% had BA occlusion.
- HARM was observed in 50% of patients on follow-up FLAIR images, always remote from the acute ischemic lesion.
- HARM was significantly associated with vessel recanalization (p=0.04), minor infarction growth (p=0.01), and smaller infarcts on follow-up DWI (p=0.05).
Conclusions:
- HARM is a common finding in PCI and correlates with favorable outcomes like vessel recanalization and limited infarct expansion.
- Neuroradiologists should recognize HARM on short-term follow-up FLAIR MRI in PCI patients who received contrast agents.
