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.

Keywords: arterial spin labeling; intracerebral hematoma; micro-arteriovenous malformation; surgery.

FIG. 1.

A: CT on admission showing the left parietal hemorrhage. B and C: T2WI (B) and TOF-MRA (C) on admission showing no abnormal vascular structure within the hematoma. D: T2WI 23 days after the hemorrhage showing a hematoma with an adjacent small low-intensity lesion (arrow). E: TOF-MRA showing slight high intensity signals at the site of a T2 low-intensity lesion (arrow). F: ASL showing clear high signal at the site of a T2 low-intensity lesion (arrow). G: Digital subtraction angiography (left, arterial phase; middle, venous phase; right, late venous phase) showing the nidus in the arterial phase (arrowhead) and the pooled contrast media within the nidus and part of the drainage system until the late venous phase (double arrowhead). H: Three-dimensional (3D) angiography (left) and a fusion image of the 3D angiography and the ASL images (right) showing the spatial correspondence of the site of the nidus and the ASL high intensity.

FIG. 2.

A: CT on admission showing the right parietal hemorrhage. B and C: T2WI (B) and TOF-MRA (C) on admission showing no abnormal vascular structure within the hematoma. D: T2WI 15 days after the hemorrhage showing a hematoma without an obvious source of bleeding. E: TOF-MRA showing slight high intensity signals at the lateral margin of the hematoma (arrow). F: ASL showing a clear high signal at the site of the TOF high intensity lesion. G: DSA (left, arterial phase; middle, venous phase; right, late venous phase) showing the nidus in the arterial phase (arrowhead) and the pooled contrast media within the nidus until the late venous phase (double arrowhead). H: Three-dimensional (3D) angiography (left) and the fusion image of the 3D angiography and the ASL images (right) showing the spatial correspondence of the site of the nidus and the ASL high intensity.