The Validity of Using Low Dose CT from FDG PET/CT Scans to Obtain Calcium Scores and Determine Patient Treatment

2530 Objectives Objective: To validate calcium scores derived using the low dose CT portion of a PET/CT scan by comparing it to the gold standard, contrast enhanced CT (cCT). Since PET/CT patients are often oncology patients, calcium scores may determine the presence and severity of coronary artery disease. Methods Methods: We retrospectively reviewed 200 FDG PET/CT scans noting coronary artery calcification and a log was kept to record cases. Thirty patients were chosen with coronary artery calcification and 14 of these also had a regular chest cCT. Calcium scores were recorded for both low dose CT and cCT scans using the Toshiba Vital computer software. Regions of interest were drawn around visibly calcified coronary arteries and a final score was given in Agaston units. The 30 scores found from the low dose CT from the PET/CT portion were also classified based on the Rotterdam Coronary Classification Table which determined the severity of coronary artery disease (Table). Results Results: In the fourteen patients, the mean calcium score for the low dose CT was 609.36 and the mean calcium score for the cCT was 624.64. In comparing the two methods, a correlation of 0.99 was observed. Using the Rotterdam scale to rank the 30 low dose CT patients, 13 patients fell in to category 3 which indicated a moderate risk of having coronary artery disease and the following 17 fell in to category 4 which indicated significant risk of a cardiovascular event within the next 5 years. Conclusions Conclusion: Use of the low-dose CT for calcium scoring is a reliable method with a correlation of 0.99 when compared to the gold standard cCT. Since many types of chemotherapy are cardiotoxic, the addition of this information in a PET/CT report may eliminate the need for dedicated cCt for calcium scoring and may help determine the presence and severity of coronary artery disease.