title: The predictive value of magnetic resonance imaging in evaluating intracranial arteriovenous malformation obliteration after stereotactic radiosurgery.
abstract: OBJECTIVE
  The current gold standard for diagnosing arteriovenous malformation (AVM) and assessing its obliteration after stereotactic radiosurgery (SRS) is digital subtraction angiography (DSA). Recently, MRI and MR angiography (MRA) have become increasingly popular imaging modalities for the follow-up of patients with an AVM because of their convenient setup and noninvasiveness. In this study, the authors assessed the sensitivity and specificity of MRI/MRA in evaluating AVM nidus obliteration as assessed by DSA.
  
  
  METHODS
  The authors study a consecutive series of 136 patients who underwent SRS between January 2000 and December 2012 and who underwent regular clinical examinations, several MRI studies, and at least 1 post-SRS DSA follow- up evaluation at the University of Virginia. The average follow-up time was 47.3 months (range 10.1-165.2 months). Two blinded observers were enrolled to interpret the results of MRI/MRA compared with those of DSA. The sensitivity, specificity, positive predictive value, and negative predictive value for the obliteration of AVM were reported.
  
  
  RESULTS
  On the basis of DSA, 73 patients (53.7%) achieved final angiographic obliteration in a median of 28.8 months. The sensitivity (the probability of finding obliteration on MRI/MRA among those for whom complete obliteration was shown on DSA) was 84.9% for one observer (Observer 1) and 76.7% for the other (Observer 2). The specificity was 88.9% and 95.2%, respectively. The false-negative interpretations were significantly related to the presence of draining veins, perinidal edema on T2-weighted images, and the interval between the MRI/MRA and DSA studies.
  
  
  CONCLUSIONS
  MRI/MRA predicted AVM obliteration after SRS in most patients and can be used in their follow-up. However, because the specificity of MRI/MRA is not perfect, DSA should still be performed to confirm AVM nidus obliteration after SRS.
authors.affiliation: Departments of 1 Neurological Surgery.|Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital;|School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China; and.
authors.forename: Cheng-Chia
authors.initials: CC
authors.lastname: Lee
authors.affiliation: Radiology & Medical Imaging, Neuroradiology Division, University of Virginia Health System, Charlottesville, Virginia;
authors.forename: Michael A
authors.initials: MA
authors.lastname: Reardon
authors.affiliation: Departments of 1 Neurological Surgery.
authors.forename: Benjamin Z
authors.initials: BZ
authors.lastname: Ball
authors.affiliation: Departments of 1 Neurological Surgery.
authors.forename: Ching-Jen
authors.initials: CJ
authors.lastname: Chen
authors.affiliation: Departments of 1 Neurological Surgery.
authors.forename: Chun-Po
authors.initials: CP
authors.lastname: Yen
authors.affiliation: Departments of 1 Neurological Surgery.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Radiology, Stanford University, Palo Alto, California.
authors.forename: Max
authors.initials: M
authors.lastname: Wintermark
authors.affiliation: Departments of 1 Neurological Surgery.|Radiation Oncology, and.
authors.forename: Jason
authors.initials: J
authors.lastname: Sheehan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011859:Radiography; D016634:Radiosurgery; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D055815:Young Adult
keywords: AVM = arteriovenous malformation; DSA = digital subtraction angiography; FSE = fast spin echo; GKS = Gamma Knife surgery; Gamma Knife; MRA = MR angiography; MRI; ROC = receiver operating characteristic; SRS = stereotactic radiosurgery; T1WI = T1-weighted imaging; T2WI = T2-weighted imaging; TOF = time of flight; arteriovenous malformation; digital subtraction angiography; obliteration; stereotactic radiosurgery; vascular disorders