Magnetic resonance imaging of pelvic entheses--a systematic comparison between short tau inversion recovery (STIR) and T1-weighted, contrast-enhanced, fat-saturated sequences.
OBJECTIVE
To assess the contribution of contrast material in detecting and evaluating enthesitis of pelvic entheses by MRI.


METHODS
Sixty-seven hip or pelvic 1.5-T MRIs (30:37 male:female, mean age: 53 years) were retrospectively evaluated for the presence of hamstring and gluteus medius (GM) enthesitis by two readers (a resident and an experienced radiologist). Short tau inversion recovery (STIR) and T1-weighted pre- and post-contrast (T1+Gd) images were evaluated by each reader at two sessions. A consensus reading of two senior radiologists was regarded as the gold standard. Clinical data was retrieved from patients' referral form and medical files. Cohen's kappa was used for intra- and inter-observer agreement calculation. Diagnostic properties were calculated against the gold standard reading.


RESULTS
A total of 228 entheses were evaluated. Gold standard analysis diagnosed 83 (36%) enthesitis lesions. Intra-reader reliability for the experienced reader was significantly (p = 0.0001) higher in the T1+Gd images compared to the STIR images (hamstring: k = 0.84/0.45, GM: k = 0.84/0.47). Sensitivity and specificity increased from 0.74/0.8 to 0.87/0.9 in the STIR images and T1+Gd sequences. Intra-reader reliability for the inexperienced reader was lower (p > 0.05).


CONCLUSIONS
Evidence showing that contrast material improves the reliability, sensitivity, and specificity of detecting enthesitis supports its use in this setting.
Department of Diagnostic Imaging, Sheba Medical Center, Tel Aviv University, Tel Hashomer, 52621, Tel Aviv, Israel.
Eyal
E
Klang
Dvora
D
Aharoni
Kay-Geert
KG
Hermann
Amir
A
Herman
Uri
U
Rimon
Nachshon
N
Shazar
Iris
I
Eshed
D000273:Adipose Tissue / Q000473:pathology*; D000465:Algorithms; D003287:Contrast Media; D005260:Female; D006621:Hip Joint / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D009942:Organometallic Compounds; D010388:Pelvis / Q000473:pathology*; D015203:Reproducibility of Results; D012216:Rheumatic Diseases / Q000473:pathology*; D012680:Sensitivity and Specificity
D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine