Bacterial pyomyositis: MRI and clinical correlation.
OBJECTIVE
To characterize the findings of magnetic resonance imaging (MRI) of bacterial pyomyositis (PM) and correlate these data with the clinical information.


METHODS
Eighty-one patients were diagnosed with PM in our institute between 1997 and 2003. Of these, 40 patients (21 male, 19 female; mean age, 53 years) also underwent MRI examination. The clinical manifestation underlying medical problems and the characteristics of MRI were analyzed. Thirty of the patients received surgical intervention or image-guided drainage/aspiration of the abscess along with administration of antibiotics, while the remaining 10 patients were promptly treated solely with antibiotics.


RESULTS
Thirty-one of 40 patients had underlying medical problems. These involved diabetes mellitus (DM, n = 16), malignancies including cervical cancer, prostate cancer, non-Hodgkin's lymphoma and acute lymphocytic leukemia (n = 10, one case also had DM), autoimmune disease or asthma with long-term steroid usage (n = 4, one case also had DM), liver cirrhosis (n = 2) and chronic renal insufficiency (n = 1). Four patients had no abscess formation at presentation (invasive or early purulent stage), while the remaining 36 cases presented with at least one abscess (purulent stage). Patients older than 40 years or DM patients tended to have larger abscess(s) (P < .05). Gadolinium-enhanced images demonstrated either thick (n = 12) or thin rim enhancement (n = 24) of the abscess wall. For those 10 patients promptly treated solely with antibiotics, nine demonstrated thin rim enhancement of the abscess (P < .05).


CONCLUSIONS
Magnetic resonance imaging plays an important role in the early recognition of bacterial PM. By precisely demarcating the extent of the disease, MRI can allow planning prompt antibiotic treatment combined with or without interventional procedures.
Yu
Chih-Wei
CW
Department of Medical Imaging, Medical College and Hospital, National Taiwan University, Taipei, Taiwan, 100.
Hsiao
Jong-Kai
JK
Hsiao
Joug-Kai
JK
Hsu
Chao-Yu
CY
Shih
Tiffany Ting-Fang
TT
D000038:Abscess / Q000175:diagnosis / Q000188:drug therapy / Q000601:surgery; D000328:Adult; D000368:Aged; D001424:Bacterial Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000601:surgery; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D009220:Myositis / Q000175:diagnosis* / Q000188:drug therapy / Q000601:surgery; D015588:Observer Variation; D011237:Predictive Value of Tests; D011859:Radiography; D012189:Retrospective Studies
D003287:Contrast Media; D019786:Gadolinium DTPA