Efficacy of arterial spin labeling for detection of the ruptured micro-arteriovenous malformation: illustrative cases

Abstract

BACKGROUND Diagnosis of a microarteriovenous malformation (micro-AVM) is difficult, especially in the acute stage of rupture because of the small size of the nidus and the existence of hematoma. We report two cases of ruptured micro-AVMs detected by arterial spin labeling (ASL). OBSERVATIONS In one case, a 45-year-old male was transported with a complaint of right hemiparesis. Computed tomography (CT) revealed a right parietal lobar hemorrhage. Standard magnetic resonance imaging (MRI) showed no abnormal findings as the cause of the hemorrhage. ASL 23 days after the onset demonstrated high signals on the medial wall of the hematoma. Digital subtraction angiography (DSA) showed a micro-AVM in accordance with the site of high signals on ASL. In another case, a 38-year-old female was transported with a complaint of left hemianopsia. CT on admission revealed a right parietal lobar hemorrhage. Standard MRI showed no abnormal findings as the cause of the hemorrhage. ASL 15 days after the onset demonstrated high signals on the internal wall of the hematoma. DSA showed micro-AVM in accordance with the site of high signaling on ASL. Both cases were successfully treated with open surgery. LESSONS ASL can manifest micro-AVMs as high signals within the hematoma. ASL is a useful less-invasive screening tool for the detection of ruptured micro-AVMs.

Current and Future Applications of Arterial Spin Labeling MRI in Cerebral Arteriovenous Malformations

“…Identification of venous-dominant AVMs from DVAs on MRI is difficult because of visual similarities [38][39][40][41][42][43][44], so much so that it has been suggested that developmental venous anomalies (DVAs) with shunting are actually a subgroup of AVMs. Another challenging lesion is micro-AVMs [18,[45][46][47][48][49][50], with a nidus of 1 cm or smaller, which pose a diagnostic challenge, especially in acute rupture. ASL sequences in MRI, with high sensitivity, help diagnose micro-AVMs.…”

“…In the acute phase of rupture due to the small size of the nidus, slow flow within the nidus, the presence of intralesional thrombosis, posthemorrhagic vascular spasm, or the compression of the nidus by the hematoma, standard MRI may be negative. However, the dedicated ASL sequence may show high signals on the inner wall of the hematoma, which is suggestive of micro-AVMs [47].…”

Arterial Spin Labeling: Key Concepts and Progress Towards Use as a Clinical Tool

“…ASL has shown sensitivity for detection of both interictal hypoperfusion 88 and ictal hyperperfusion 89 in epilepsy. Vascular malformations with shunted flow, such as arteriovenous malformations, frequently display very hyperintense signal on ASL that can be used for detection 90 or monitoring for successful therapy. 91 CBF changes in traumatic brain injury have been reported, possibly suggesting early hyperperfusion 92 followed by normalization and reduction, 93 but variability of changes across studies 94 is high.…”

Efficacy of repeat arterial spin labeling for angiogram-negative ruptured micro-arteriovenous malformation: A case report

“…[ 2 - 5 , 11 ] In addition, one study previously reported the efficacy of ASL in detecting ruptured micro-AVM. [ 8 ] In the case, a high ASL signal was observed in the nidus, and it was thought to reflect pooled blood within the nidus, which was observed by DSA. Here, we report a case of micro-AVM identified by a repeat ASL for the first time in the chronic stage.…”