OBJECTIVE: Although three-dimensional time-of-flight magnetic resonance angiography (3D TOF-MRA) is used frequently as a follow-up tool to assess the response of arteriovenous malformations (AVMs) after radiosurgery, the diagnostic accuracy of 3D TOF-MRA is not well known. We evaluated the diagnostic accuracy of contrast-enhanced 3D TOF-MRA at 3.0 Tesla for the detection of residual AVMs. MATERIALS AND METHODS:This study included 32 AVMs from 32 patients who had been treated with radiosurgery (males/females: 21/11; average patient age, 33.1 years). The time interval between radiosurgery and MRA was an average of 35.3 months (range, 12-88 months). Three-dimensional TOF-MRA was obtained at a magnetic field strength of 3.0 Tesla after infusion of contrast media, with a measured voxel size of 0.40 x 0.80 x 1.4 (0.45) mm3 and a reconstructed voxel size of 0.27 x 0.27 x 0.70 (0.05) mm3 after zero-filling. X-ray angiography was performed as the reference of standard within six months after MRA (an average of two months). To determine the presence of a residual AVM, the source images of 3D TOF-MRA were independently reviewed, focusing on the presence of abnormally hyperintense fine tangled or tubular structures with continuity as seen on consecutive slices by two observers blinded to the X-ray angiography results. RESULTS: A residual AVM was identified in 10 patients (10 of 32, 31%) on X-ray angiography. The inter-observer agreement for MRA was excellent (kappa= 0.813). For the detection of a residual AVM after radiosurgery as determined by observer 1 and observer 2, the source images of MRA had an overall sensitivity of 100%/90% (10 of 10, 9 of 10), specificity of 68%/68% (15 of 22, 15 of 22), positive predictive value of 59%/56% (10 of 17, 9 of 16), negative predictive value of 100%/94% (15 of 15, 15 of 16) and diagnostic accuracy of 78%/75% (25 of 32, 24 of 32), respectively. CONCLUSION: The sensitivity of contrast-enhanced 3D TOF-MRA at 3.0 Tesla is high but the specificity is not sufficient for the detection of a residual AVM after radiosurgery.
Adult ; Contrast Media ; Female ; Humans ; Intracranial Arteriovenous Malformations/*diagnosis/*surgery ; Magnetic Resonance Angiography/methods/*standards ; Male ; *Radiosurgery ; Sensitivity and Specificity

A 36-year-old man was diagnosed with a right temporal lobe grade II cerebral arteriovenous malformation (cAVM) and was treated with radiosurgery. At nine months after the cAVM radiosurgery, the patient began to develop bilateral focal narrowing at the M1 segments of the bilateral middle cerebral arteries. The narrowing progressively deteriorated as was demonstrated on longitudinal serial follow-up MR imaging. X-ray angiography performed at 51 months after radiosurgery confirmed that the cAVM was cured and a diagnosis of moyamoya disease. To the best of our knowledge, this is the first case of cAVM-associated moyamoya disease that developed after radiosurgery. Given the chronological sequence of disease development and radiation dose distribution of radiosurgery, it is proposed that humoral or unknown predisposing factors, rather than direct radiation effects, are the cause of moyamoya disease associated with cAVM.
Adult ; Humans ; Intracranial Arteriovenous Malformations/diagnosis/*surgery ; Magnetic Resonance Imaging ; Male ; Moyamoya Disease/*etiology ; Postoperative Complications ; Radiosurgery