MR Imaging of arrhythmogenic right ventricular cardiomyopathy: morphologic findings and interobserver reliability.
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 T(1) signal (fat) in the myocardium, and (e) location of high T(1) signal (fat) on a Likert scale with formatted responses.


RESULTS
Readers indicated that the Task Force ARVC/D cases had significantly more (chi(2) = 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 (chi(2)(= )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 (chi(2) = 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 (chi(2) = 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.
Bluemke
David A
DA
Department of Radiology, Johns Hopkins Hospital, Baltimore, MD 21287, USA. dbluemke@jhmi.edu
Krupinski
Elizabeth A
EA
Ovitt
Theron
T
Gear
Kathleen
K
Unger
Evan
E
Axel
Leon
L
Boxt
Lawrence M
LM
Casolo
Giancarlo
G
Ferrari
Victor A
VA
Funaki
Brian
B
Globits
Sebastian
S
Higgins
Charles B
CB
Julsrud
Paul
P
Lipton
Martin
M
Mawson
John
J
Nygren
Anders
A
Pennell
Dudley J
DJ
Stillman
Arthur
A
White
Richard D
RD
Wichter
Thomas
T
Marcus
Frank
F
D000328:Adult; D000368:Aged; D019571:Arrhythmogenic Right Ventricular Dysplasia / Q000175:diagnosis*; D016022:Case-Control Studies; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011336:Probability; D012016:Reference Values; D012042:Registries; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index