Fahim Hassan

Beware of the focal uptake at the ischium on the bone scan in prostate cancer.

RationaleThe isotope bone scan is routinely used in the management of prostate cancer as the skeleton is the second most common area of metastasis after lymph nodes. A classic site of involvement in the pelvis is the ischium, and the aim of this study was to assess the value of single-photon emission computed tomography/computed tomography (SPECT/CT) imaging in patients with focal ischial uptake on the planar scan. Materials and methodsThis was a retrospective study of consecutive 150 patients with prostate cancer who were referred for a whole-body bone scan between August 2007 and 2008. Two experienced nuclear medicine consultants along with a musculoskeletal radiologist reviewed the scans. ResultsSixty-eight patients were diagnosed with widespread metastases and 46 patients showed typical degenerative disease changes on planar whole-body imaging. SPECT/CT imaging was done in 36 patients to clarify the diagnosis in areas of indeterminate uptake noted on planar whole-body imaging. Ten of these 36 patients who had focal increased ischial uptake were included in the study. Only three of these 10 patients were diagnosed as having a metastatic lesion with the presence of an enthesopathy, a common finding. ConclusionIsolated focal uptake in the ischium is a relatively common finding in patients with prostate cancer and there is concern that this, on occasion, could be misinterpreted as metastasis. SPECT/CT imaging has an important role in differentiating a benign from a malignant lesion.

Clinical Utility of SPECT/CT Imaging Post-Radioiodine Therapy: Does It Enhance Patient Management in Thyroid Cancer?

Background: The aim of this study was to evaluate post-therapy iodine-131 single-photon emission computed tomography/computed tomography (131I-SPECT/CT) imaging in comparison to conventional planar 131I whole-body imaging, and to assess its clinical impact on the management of patients. Methods: We retrospectively reviewed planar 131I whole-body and 131I-SPECT/CT imaging findings in 67 patients who underwent 131I therapy for thyroid cancer. Two nuclear medicine physicians reviewed the scans independently. The foci of increased tracer uptake were identified in the neck, thorax and elsewhere. Within the neck, the foci of 131I-increased uptake were graded qualitatively as probable or definite uptake in thyroid remnants and probable or definite uptake in the lymph nodes. Serum thyroglobulin level, histopathology and other imaging findings served as the reference standard. Results: Of the 67 patients, 57 (85%) had radioiodine avid disease and 10 (15%) demonstrated non-radioiodine avid disease. Overall, post-therapy 131I-SPECT/CT downstaged lymph node staging in 10 patients and upstaged it in 4 patients. This translated into a change of management for 9/57 (16%) patients with radioiodine avid disease. A change of management was observed in 5/10 patients with non-radioiodine avid disease confirmed in the post-131I-SPECT/CT study. Additionally, clinically significant findings such as incidental lung cancer, symptomatic pleural effusion and consolidation were also diagnosed in both groups of patients. Conclusion: In patients with thyroid cancer, 131I-SPECT/CT is a valuable addition to standard post-therapy planar imaging. SPECT/CT also improved diagnostic confidence and provided crucial clinical information leading to change of management for a significant number of these patients.

Soft Tissue Uptake in Radionuclide Bone Scintigraphy

Patients with suspected malignancy, infection, inflammation, trauma, or metabolic bone disease are referred for bone scintigraphy to establish the extent, if any, of skeletal involvement. Often, extra-osseous uptake of radiotracer is identified, which may either be an incidental finding or relevant to the underlying bone pathology.