Noninvasive Volume Measurement of Cerebral Arteriovenous Malformation Nidus: Silent MRA Compared with TOF-MRA

BACKGROUND AND PURPOSE: Accurate cerebral arteriovenous malformation (CAVM) nidus volume measurement is important for evaluating treatment strategy and neurologic prognosis. This study aimed to compare the accuracy of silent MRA for measuring CAVM nidus volume with TOF-MRA and to analyze the clinical factors that may affect the nidus volume measurement. MATERIALS AND METHODS: A total of 45 patients diagnosed with CAVM who received silent MRA, TOF-MRA, and DSA examinations were retrospectively enrolled. A standardized protocol was used for nidus volume measurement using thresholding by these three imaging tools. RESULTS: The mean nidus volume measured by 3D-DSA, silent MRA, and TOF-MRA was 9.073 (SD, 7.667) mL, 9.55 (SD, 7.814) mL, and 7.773(SD, 7.11) mL, respectively. The linear correlation coefficient of the nidus volume was 0.976 (P < .001) and .966 (P < .001), respectively. Silent MRA was significantly higher than TOF MRA in nidus overlap volume (0.775 [SD. 0.109] versus 0.538 [SD. 0.206] P = .00), while TOF MRA was significantly higher than silent MRA in absolute volume difference (0.196 [SD. 0.192] versus 0.114 [SD. 0.147], P = .005). For both silent MRA and TOF-MRA, the nidus overlap volume and absolute volume difference were significantly associated with previous embolization status. CONCLUSIONS: Nidus volume measurement by silent MRA is comparable with DSA and is practical. Silent MRA can be used for nidus volume measurement and as a follow-up tool for evaluating nidus volume change after therapy.