Sensitivity of MR arthrography in the evaluation of acetabular labral tears.
OBJECTIVE
MRI has historically provided suboptimal visualization of tears of the acetabular labrum. Degenerative fraying and underlying cartilage abnormalities can often mimic tears of the labrum on conventional MRI. Administration of intraarticular gadolinium enhances the MRI appearance of the labrum to improve detection of labral abnormalities. This study examined the improved diagnostic sensitivity of MR arthrography compared with conventional MRI and the importance of confining the study to a small field of view.


METHODS
Fifty-one hips were imaged in 48 patients. Fourteen hips underwent conventional MRI with a large field of view (30-38 cm). Seven hips underwent conventional MRI with a small field of view (14-20 cm). Thirty hips underwent MR arthrography with a small field of view (14-20 cm). Labral tears were diagnosed when contrast material was identified within the labrum or between the labrum and the acetabulum, when a displaced fragment was noted, or when a paralabral cyst was identified. All study results were compared with findings at the time of hip arthroscopy.


RESULTS
Conventional MRI with a large field of view was 8% sensitive in detecting labral tears compared with findings at the time of arthroscopy. Diagnostic sensitivity was improved to 25% with a small field of view. MR arthrography with a small field of view was 92% sensitive in detecting labral tears.


CONCLUSIONS
A combination of MR arthrography and a small field of view is more sensitive in detecting labral abnormalities than is conventional MRI with either a large or a small field of view.
Toomayan
Glen A
GA
Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA. glen.toomayan@duke.edu
Holman
W Russell
WR
Major
Nancy M
NM
Kozlowicz
Shannon M
SM
Vail
T Parker
TP
D000077:Acetabulum / Q000293:injuries*; D000293:Adolescent; D000328:Adult; D001182:Arthroscopy; D002358:Cartilage, Articular / Q000293:injuries*; D016009:Chi-Square Distribution; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D003287:Contrast Media; D019786:Gadolinium DTPA