Bone marrow abnormalities of foot and ankle: STIR versus T1-weighted contrast-enhanced fat-suppressed spin-echo MR imaging

To compare short inversion time inversion-recovery (STIR) and T1-weighted contrast material-enhanced fat-suppressed spin-echo magnetic resonance (MR) sequences for depiction of bone marrow abnormalities of the foot and ankle.

Fifty-one consecutive patients with bone marrow abnormalities depicted on turbo STIR images were examined with additional T1-weighted contrast-enhanced (0.1 mmol/kg gadopentetate dimeglumine) MR imaging with fat suppression. Volume and signal difference-to-noise ratio (SDNR) were measured. An additional qualitative analysis was performed by two experienced musculoskeletal radiologists to correlate the presence or absence of ill-defined edema-like zones, well-defined zones, and cystlike zones. Diagnoses determined with MR findings with each sequence were compared with the results of a review panel. Correlation coefficients (r(2)) and paired t tests were calculated for all measurements. Agreement percentages and kappa values were calculated for inter- and intraobserver reproducibility.

Regarding volume of bone marrow abnormalities, a high correlation (r(2) = 0.98) of both sequences was found. SDNR was substantially higher on T1-weighted contrast-enhanced images than on STIR images (mean, 125.9 vs 95.4; P <.001). The qualitative analysis demonstrated identical imaging patterns with both sequences in 96% (79 of 82, kappa = 0.38) of ill-defined zones, in 88% (72 of 82, kappa = 0.76) of well-defined zones, and in 98% (80 of 82, kappa = 0.84) of cystlike zones. Interobserver reproducibility of the three imaging patterns was similar for both sequences. The kappa values for these three zones with STIR sequence were 0.55, 0.68, and 0.69, and those for the T1-weighted contrast-enhanced MR sequence were 0.49, 0.73, and 0.58, respectively. Diagnoses determined with MR findings were equal with both sequences in 94% (80 of 85) of involved bones.

STIR images and T1-weighted contrast-enhanced fat-suppressed MR images demonstrate almost identical imaging patterns, and diagnoses determined with these findings show little difference.