Imaging through liver or mid-thigh in cardiac sarcoid PET/CT patients: which is more appropriate?

Objectives: The purpose of this research was to determine which PET/CT imaging method is more appropriate in cardiac sarcoid imaging. Two imaging methods include scanning from the base of the skull to mid-thigh or from the base of the skull through the liver.

Background: Sarcoidosis is an autonomous disease with an unknown etiology, which may occur in many different regions of the body, but is most commonly found in the lungs and mediastinal lymph nodes. The disease manifests as a collection of granulomas (inflammatory cells) in the affected organ(s). PET/CT imaging with ¹⁸F-FDG is currently used to detect these sites of inflammation within the body.¹

Methods: In a retrospective study, 91 patients’ images were evaluated for ¹⁸F-FDG uptake within the cardiac region. Scans with positive cardiac sarcoidosis were then further evaluated to determine if there was any abnormal ¹⁸F-FDG uptake within the lungs, and elsewhere in the body.

Results: Fifty-four patients (59.3%) imaged resulted in ¹⁸F-FDG cardiac uptake. Of the total studied population 69 (75.8%) were imaged from skull base to mid-thigh and 22 (24.2%) were imaged from skull base through the liver. Forty-three (62.3%) patients from the imaging cohort skull base to mid-thigh demonstrated ¹⁸F-FDG activity outside of the pulmonary region. Of the 43 patients, disease below the liver was found in 18 (41.9%) patients. From the imaging cohort skull base through the liver 12 (54.5%) of the patients demonstrated ¹⁸F-FDG activity outside of the pulmonary region.

Conclusions: In this study almost 42% of patients scanned to mid-thigh demonstrated disease outside the mediastinum and below the liver. Based on these findings it would seem that imaging to mid-thigh may be beneficial to patients undergoing cardiac PET/CT imaging.