Clinical significance of abnormal nonosseous soft tissue uptake of bone tracer

Objective To evaluate the clinical significance of abnormal soft tissue uptake of bone tracer.Methods Thirty patients with abnormal soft tissue uptake of bone tracer on ~(99)Tc~m-methylene diphosphonic acid(MDP)skeletal imaging were analyzed.Radioactivity of soft tissue accumulated equal to or greater than the ribs were considered as abnormal.The result was compared with pathology,MRI,CT, X-ray,ultrasound,findings for evaluating its clinical significance.Results In 7 patients with diffuse liver uptake of ~(99)Tc~m-MDP,6 were massive and 1 nodular liver cancer.In 2 patients with local liver uptake,one was metastatic and the other primary liver cancer.In 5 local lung uptake cases 4 were primary lung cancer and one metastatic.In 5 cases with colonic uptake 1 was schistosomiasis while the other 4 unexplainable. Subcutaneous tissue uptake was observed in 4 patients,symmetrical uptake in 2 patients with metastatic cal- cification microfoci in multiple myeloma,unsymmetrical uptake in 2 patients with hemangioma and abscess. Pleural uptake in 3 patients all was metastatic cancer.Abdominal uptake in 3 patients was omentum,para- vertebral soft tissue metastasis and unknown cause.Breast uptake in one patient was due to breast cancer. Conclusions There are many causes resulting in abnormal nonosseous soft tissue uptake of ~(99)Tc~m-MDP. The final diagnosis should correlate with clinical data and other examinations.