Findings on low dose CT performed for SPECT-CT imaging: A 10 month audit

Learning Objectives Appreciate the frequency & utility of incidental findings seen on low-dose CT performed for SPECT-CT imaging.

Summary: Low dose CT from all SPECT-CT's were reviewed separately by blinded, dual-qualified radiologist/nuclear medicine physicians and findings recorded. A consenus meeting was then held to reach agreement for any discrepant findings. Study indications & scintigraphic findings were revealed. Findings were divided into being i) relevant to study indication or ii) incidental. The incidental finding group was divided into those which did and did not require clinical or imaging follow-up, Review of any diagnostic CT imaging performed before SPECT-CT was conducted. 163 SPECT-CT's were performed. 298 incidental low-dose CT findings were seen in 121 patients. 242 incidental CT findings did not warrant follow-up. 56 incidental CT findings (affecting 41 patients) required follow-up; 25 incidental findings requiring follow-up were already known from previous diagnostic CT. 31 incidental findings were not previously known and required follow-up, affecting 24 patients. 61 % of patients (100) demonstrated CT findings relevant to their indication for SPECT-CT scanning, Low dose CT detects anatomic abnormality relevant to clinical presentation in a majority of cases. Most patients (75%) demonstrated an incidental finding on low dose CT, with most of these findings (81%) not needing follow-up. A small, but significant number of patients (15%) with clinically important, previously unidentifed incidental findings exists.