ACUTE EXPERIMENTAL OSTEOMYELITIS AND ABSCESSES - DETECTION WITH MR IMAGING VERSUS CT

Acute experimental osteomyelitis and abscesses were induced in the proximal tibia and surrounding soft tissues, respectively, in 67 New Zealand white rabbits. Fifty-three rabbits were injected with a Staphylococcus aureus solution and 26, with sterile saline in tibial medullae and/ or surrounding soft tissues. Contrast material-enhanced computed tomography (CT) and magnetic resonance (MR) imaging were performed 7 days after inoculation. Immediately after imaging, the animals were killed and necropsy was performed. MR imaging was more sensitive than CT in the detection of osteomyelitis (94% vs 66%, P < .025) and abscesses (97% vs 52%, P < .001). MR imaging was equally specific as CT in the exclusion of osteomyelitis (93% vs 97%, χ2 = 0) but less specific than CT in the exclusion of abscesses (77% vs 100%, P < .025). The overall accuracy of MR imaging was somewhat, although not significantly, greater than that of CT in the detection of both osteomyelitis (93% vs 80%) and abscesses (87% vs 75%).