⁹⁹Tc^m-MDP whole body bone imaging in 25 patients with SAPHO syndrome

Objective: To investigate the usefulness of ⁹⁹Tc^m-MDP whole body bone scintigraphy (WBBS) in patients with synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome. Methods: ⁹⁹Tc^m- MDP WBBS was performed in 25 patients (6 males, 19 females, mean age=(55.1 ±9.8) years) with SAPHO syndrome. Bone lesions were classified into five categories: anterior chest wall, spine, mandible, sacroiliac joint, and limbs. The typical scintigraphic manifestations of SAPHO syndrome were summarized and compared to other radiological imaging data. Results: Among 25 patients, 32% of cases (8/25) were associated with skin lesion; 48% (12/25) were pathologically diagnosed with chronic nonspecific bone inflammation by bone biopsy. On ⁹⁹Tc^m-MDP WBBS, abnormal metabolic foci at anterior chest wall were found in all cases, most of which located in the sternocostoclavicular region (96%, 24/25), including sternoclavicular joints (60%, 15/25), first costosternal junctions (48%, 12/25), and manubriosternal junctions (44%, 11/25). Only 20% of the patients (5/25) demonstrated the typical scintigraphic characteristic: 'bull's head' sign. The second most frequent part was spine (44%, 11/25). Appendicular skeleton was affected in 16% (4/25) patients. WBBS also demonstrated additional skeletal lesions in 68% (17/25) of the patients, mainly in first costosternal junctions (7 patients), sternoclavicular joints (6 patients), manubriosternal junctions (5 patients) and spine (4 patients). Conclusions: Abnormal metabolic foci in sternocostoclavicular region and other imaging manifestations on ⁹⁹Tc^m- MDP WBBS can be used to diagnose, differentiate, and localize the insidious lesion and evaluate the lesion activity in patients with SAPHO syndrome. (authors)