Reason: prior mri shows fluid asymmetry, R>L in pelvis, w/ concern for possible infection. Want to study w/ contrast to assess infection vs mass vs fx. Given hx of prior lumbar spine surgery, would also like L spine included. Will place additional order. History: pt now has fever. Also has severe low back to posterior pelvis to thigh pain w/ tenderness to palpation. This is severe acute worsening Again seen is an enhancing increased signal abnormality about the right sacroiliac joint involving the right sacral wing and right iliac bone appearing similar to the prior study. There is enhancing signal abnormality involving the right iliacus and gluteal musculature in the surrounding area likely reflecting inflammatory change. There is also a small amount of fluid within the right sacroiliac joint. No soft tissue ulceration is identified. There is diffuse bone marrow signal abnormality affecting the bones of the image axial and proximal appendicular skeleton which is nonspecific. While this can be seen in anemia, the possibility of a myeloproliferative disorder cannot be excluded. The imaged musculature of the pelvis is otherwise unremarkable. Although this examination was not protocoled for detailed evaluation of the pelvic viscera, no acute abnormality is identified.
Enhancing signal abnormality about the right sacroiliac joint is most likely related to the previously described insufficiency fractures, although superimposed infection cannot be completely excluded by this examination. Further evaluation with a dedicated CT examination is recommended to confirm the presence of insufficiency fractures. Other findings as described above.