Verification bias in assessment of the utility of MRI in the diagnosis of cruciate ligament tears.
OBJECTIVE
The purpose of this study was to investigate the extent to which verification bias affects the sensitivity and specificity of MRI in the diagnosis of cruciate ligament tears.


METHODS
Consecutively registered outpatients who underwent MRI evaluation of the knee were included in the study. The sensitivity and specificity of MRI were calculated for patients whose diagnosis was verified with arthroscopy. For patients who did not undergo arthroscopy, the effect of verification bias was estimated with global sensitivity analysis, a technique of graphic representation of whether a particular combination of sensitivity and specificity estimates is compatible with the observed data.


RESULTS
Among the 356 patients included in the study, 82 patients (23%) had the MRI findings verified at arthroscopy. The sensitivity and specificity of MRI among patients who underwent arthroscopy were 38% and 90%. For patients whose disease status was not verified with arthroscopy, the influence of verification bias was estimated with global sensitivity analysis. The sensitivity of MRI ranged from 3% to 73%, and the specificity from 63% to 98%. The region comprising all possible combinations of sensitivity and specificity had a butterfly shape. The sensitivity and specificity pair estimated from cases verified with arthroscopy was included in this region.


CONCLUSIONS
Verification bias did not greatly affect assessment of the diagnostic utility of MRI in the evaluation of cruciate ligament tears. The high specificity previously reported for MRI can be considered valid, but the sensitivity may not be as reliable.
Department of Healthcare Economics and Quality Management, Kyoto University Graduate School of Medicine, Yoshida Konoe-cho, Sakyo-ku, Japan.
Haruo
H
Nishikawa
Yuichi
Y
Imanaka
Miho
M
Sekimoto
Hiroshi
H
Ikai
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000070598:Anterior Cruciate Ligament Injuries; D001182:Arthroscopy; D016009:Chi-Square Distribution; D002648:Child; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity