22-year-old male with worsening pain and drainage while on antibiotics. Assess status of osteomyelitis of the coccyx and adjacent fluid pocket. Again seen is ulceration of the soft tissues posterior to the coccyx. Inflammation extends from this ulceration into the subcutaneous fat along the gluteal crease which abuts the inferior margin of the bones of the coccyx. Although this inflammation appears similar to that seen on the prior study, the fluid pocket seen on the prior study has decreased in size. There is a small focus of gas within this collection. A discrete C1 segment, visible on the prior study, is not evident on the current examination, presumably related to interval destruction from osteomyelitis. Although there is mild residual edema within the C2 segment on the fluid sensitive sequences, the marrow appears largely fatty on T1-weighted images suggesting some interval healing. Enhancing inflamed tissue extends between the S5 and C2 segments. There is mild edema within the S5 segment on the fluid sensitive sequences but preservation of normal bone marrow signal on T1-weighted images, suggesting reactive osteitis rather than osteomyelitis.There is a small collection of rim-enhancing fluid adjacent to the inferior aspect of the ischial tuberosity that appears to communicate with the overlying skin surface via an enhancing sinus tract. This small amount of fluid appears to have decreased when compared to the prior study. There is no evidence of osteomyelitis of the ischium. A similar sinus tract is noted on the right that likely contacts the ischial cortex, but we see no associated fluid collection or evidence of osteomyelitis. We see no additional foci of osteomyelitis. There is loss of the soft tissue posterior to the right greater trochanter with mild enhancement along the trochanters bilaterally, suggesting inflammation, but we see no findings to suggest osteomyelitis. There is free fluid within the pelvis which is nonspecific.
1. Decubitus ulcer as described above with decrease in size of "fluid pockets" seen on the prior study.2. Sinus tract extending to both ischia without evidence of osteomyelitis.3. Other findings as described above.