The mean age was 47.9 ± 14.8 years; 69% were female. Classic DM accounted for 69%, amyopathic 28%, and juvenile 3%. The mean disease duration was 11 months. STIR hyperintensity was symmetric in 62.5%, asymmetric in 12.5%, and absent in 25%. Fascial/subcutaneous hyperintensity occurred in 59%. Lower-limb muscles were most frequently involved (72%), followed by gluteal (50%), shoulder girdle (41%), and trunk (28%). Pelvic muscles—particularly the gluteus, obturator internus/externus, and pectineus—were commonly affected, representing a distinctive pattern. STIR signal intensity correlated positively with serum CPK. One patient (3%) had paraneoplastic DM secondary to breast carcinoma. Nine amyopathic cases demonstrated subcutaneous hyperintensity despite normal enzyme levels.