MO011: The Use of a 4-Point Scoring Scale in 18F-FDG-PET/CT Imaging Helps for Diagnosis of Renal and Hepatic CYST Infections in Patients with Autosomal Dominant Polycystic Kidney Disease: A Validation Cohort

Abstract

Abstract BACKGROUND AND AIMS Autosomal dominant polycystic kidney disease (ADPKD) is prone to multiple complications, including cyst infection (CyI). 18F-FDG PET/CT imaging proved useful in the diagnosis of renal and hepatic CyI. A 4-point scale comparing the uptake of 18F-FDG in the suspected infected cyst versus the hepatic physiological background has been proposed. We performed an independent validation of this semi-quantitative score system. METHOD All ADPDK patients hospitalized between January 2007 and March 2019 who underwent an 18F-FDG PET/CT for suspected CyI were retrospectively identified using computer-based databases. Medical files were systematically reviewed. CyI was conventionally defined by: fever (>38°C), abdominal pain, increased plasma CRP levels (≥70 mg/dL), absence of any other cause of inflammation and favorable outcomes after ≥21 days of antibiotics. The 18F-FDG uptake around the suspected CyI was evaluated using the 4-point scale. Stats were performed using SAS version 9.4. RESULTS Our cohort included 51 18F-FDG PET/CT in 51 patients, including 11 cases of CyI according to the above-detailed definition. The agreement between the 4-point scale and the gold-standard criteria of CyI was significant, with an odds ratio of 6.03 for CyI in case of a score ≥3 (P, 0.014). The corresponding sensitivity and specificity of PET/CT using the 4-point scale were 63.3% and 77.5%, respectively. CONCLUSION Our independent validation cohort confirms that the use of a semi-quantitative 4-point scoring system helps in the diagnosis of CyI by 18F-FDG PET/CT imaging in patients with ADPKD.