Tamar Gaspar MD, Presenter: Nothing to Disclose

Alex Frenkel DSC, Abstract Co-Author: Nothing to Disclose

Ora Israel MD, Abstract Co-Author: Research Consultant, General Electric Company

Zohar Keidar MD, PhD, Abstract Co-Author: Nothing to Disclose

Bone scan (BS) is the most frequently performed general nuclear medicine procedure. Recently bone SPECT/CT has been advocated for optimized localization and characterization of foci of increased 99mTc-MDP uptake. Our purpose was to establish the frequency and significance of unexpected abnormalities detected on the CT component of bone SPECT/CT performed with a new hybrid scanner (Discovery 670, GE Healthcare) combining a dual-head SPECT and 16-slice CT.

107 patients (mean age 53y, 59% men) underwent BS with SPECT/CT during a 12 month testing period. Indications for BS included: skeletal pain (45%), suspected fracture/osteomyelitis (22%), follow-up of prior imaging tests (21%) and metastatic survey (12%). The SPECT/CT field-of-view was determined based either on the clinical referral indication or any abnormal uptake on planar BS. CT parameters were 120kV & 40-200mAs for adults and 100kV & 20-100mAs for children using software to minimize radiation dose based on the body part diameter ("smart mA", GE Healthcare). A fixed 40cm scan length was used with 3.75 mm slice thickness reconstruction. The CT component was analyzed retrospectively by an experienced reader. Abnormal CT findings were recorded and classified based on their clinical significance and location.

The 107 CTs included: 28 abdominal, 13 pelvic, 16 combined lower chest & abdomen, 20 chest & neck and 30 scans of the limbs. 18 patients had normal CT scans. There were 211 abnormal CT findings, with 66 relating to the reason for referral. Remaining 145 unexpected lesions (in 64 patients) were divided into major findings (47, 32%) requiring further investigation or follow-up, and minor findings (98, 68%) that should be reported but are of no further clinical consequence.

Incidental findings on the CT component were found in 60% of patients undergoing BS-SPECT/CT with one third of them of clinical significance requiring either further investigation or follow-up.

Establish the frequency and significance of incidental CT findings detected on bone SPECT/CT performed for optimized localization and characterization of increased uptakes

Gaspar, T, Frenkel, A, Israel, O, Keidar, Z, Incidental CT Findings on Bone SPECT/CT: Clinical Significance.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11009112.html