MR Imaging of Arrhythmogenic Right Ventricular Cardiomyopathy: Morphologic Findings and Interobserver ReliabilityBluemke D.A. · Krupinski E.A. · Ovitt T. · Gear K. · Unger E. · Axel L. · Boxt L.M. · Casolo G. · Ferrari V.A. · Funaki B. · Globits S. · Higgins C.B. · Julsrud P. · Lipton M. · Mawson J. · Nygren A. · Pennell D.J. · Stillman A. · White R.D. · Wichter T. · Marcus F.
aSarver Heart Center and bDepartment of Radiology, University of Arizona, Tucson, Ariz., cDepartment of Radiology, University of Pennsylvania, Philadelphia, Pa., dDepartment of Radiology, Johns Hopkins Hospital, Baltimore, Md., eDepartment of Radiology, Beth Israel Medical Center, New York, N.Y., USA; fDepartment of Cardiology, Istituto di Clinica Medica e Cardiologia, Florence, Italy; gDepartment of Medicine, University of Pennsylvania, Philadelphia, Pa., USA; h3rd Department of Internal Medicine, Central Hospital, St. Pölten, Austria; iDepartment of Radiology, University of California San Francisco, San Francisco, Calif., jDepartment of Radiology, Mayo Clinic, Rochester, Minn., kDepartment of Radiology, University of Chicago, Chicago, Ill., USA; lDepartment of Radiology, Children’s and Women’s Health Center of British Columbia, Vancouver, Canada; mDepartment of Radiology, University of Uppsala, Uppsala, Sweden; nDepartment of Cardiovascular MR, Royal Brompton Hospital, London, UK; oDepartment of Radiology, University of Minnesota, Minneapolis, Minn., pDepartment of Radiology, Cleveland Clinic Foundation, Cleveland, Ohio, USA;qDepartment of Cardiology and Angiology, University of Münster, Münster, Germany
Background: Magnetic resonance (MR) imaging is frequently used to diagnose arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). However, the reliability of various MR imaging features for diagnosing ARVC/D is unknown. The purpose of this study was to determine which morphologic MR imaging features have the greatest interobserver reliability for diagnosing ARVC/D. Methods: Forty-five sets of films of cardiac MR images were sent to 8 radiologists and 5 cardiologists with experience in this field. There were 7 cases of definite ARVC/D as defined by the Task Force criteria. Six cases were controls. The remaining 32 cases had MR imaging because of clinical suspicion of ARVC/D. Readers evaluated the images for the presence of (a) right ventricle (RV) enlargement, (b) RV abnormal morphology, (c) left ventricle enlargement, (d) presence of high T1 signal (fat) in the myocardium, and (e) location of high T1 signal (fat) on a Likert scale with formatted responses. Results: Readers indicated that the Task Force ARVC/D cases had significantly more (χ2 = 119.93, d.f. = 10, p < 0.0001) RV chamber size enlargement (58%) than either the suspected ARVC/D (12%) or no ARVC/D (14%) cases. When readers reported the RV chamber size as enlarged they were significantly more likely to report the case as ARVC/D present (χ2= 33.98, d.f. = 1, p < 0.0001). When readers reported the morphology as abnormal they were more likely to diagnose the case as ARVC/D present (χ2 = 78.4, d.f. = 1, p < 0.0001), and the Task Force ARVC/D (47%) cases received significantly more abnormal reports than either suspected ARVC/D (20%) or non-ARVC/D (15%) cases. There was no significant difference between patient groups in the reported presence of high signal intensity (fat) in the RV (χ2 = 0.9, d.f. = 2, p > 0.05). Conclusions: Reviewers found that the size and shape of abnormalities in the RV are key MR imaging discriminates of ARVD. Subsequent protocol development and multicenter trials need to address these parameters. Essential steps in improving accuracy and reducing variability include a standardized acquisition protocol and standardized analysis with dynamic cine review of regional RV function and quantification of RV and left ventricle volumes.