Hans Balink1, Roel J Bennink, Nic J G M Veeger, Berthe L F van Eck-Smit, Hein J Verberne. 1. From the *Department of Nuclear Medicine, Medical Center Leeuwarden, Leeuwarden; †Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, Amsterdam; and ‡Department of Epidemiology, University Medical Center Groningen, Groningen, the Netherlands.
Abstract
OBJECTIVES: The goal of this multicenter retrospective study was to evaluate the contribution of F-FDG PET/CT in the diagnosis of patients with inflammation of unknown origin (IUO). In addition, C-reactive protein (CRP) level and erythrocyte sedimentation rate were assessed as possible predictors for the outcome of F-FDG PET/CT. METHODS: Inflammation of unknown origin was defined as prolonged and perplexing inflammation, with repeated CRP levels more than 20 mg/L or erythrocyte sedimentation rate more than 20 mm/h, body temperature of less than 38.3°C, and without a diagnosis after a variety of conventional diagnostic procedures.A total of 140 patients with IUO (67 men, 73 women; mean age, 64.2 years; age range, 18-87 years) underwent F-FDG PET/CT. F-FDG PET/CT was considered helpful when the imaging findings led to a diagnosis, either confirmed by histopathology, microbiological assays, clinical and imaging follow-up, or response to treatment. RESULTS: In 104 patients (73%), a final diagnosis could be established as follows: infection in 35 patients, malignancy in 18 patients, noninfectious inflammatory disease in 44 patients, and a variety of uncommon conditions in 7 patients. F-FDG PET/CT was true positive in 95 patients, true negative in 30 patients (ie, self-limiting conditions), false positive in 6 patients, and false negative in 9 patients (predominantly systemic diseases). In this population, the positive predictive value, negative predictive value, and diagnostic accuracy of F-FDG PET/CT were 94%, 77%, and 89%, respectively. In a multivariate analysis, CRP was the only independent predictor for the outcome of F-FDG PET/CT. CONCLUSIONS: F-FDG PET/CT correctly identified or excluded a causal explanation in approximately 90% of patients with IUO. However, a negative F-FDG PET/CT is indicative for a self-limiting condition only after systemic diseases are excluded by other diagnostic tests.
OBJECTIVES: The goal of this multicenter retrospective study was to evaluate the contribution of F-FDG PET/CT in the diagnosis of patients with inflammation of unknown origin (IUO). In addition, C-reactive protein (CRP) level and erythrocyte sedimentation rate were assessed as possible predictors for the outcome of F-FDG PET/CT. METHODS:Inflammation of unknown origin was defined as prolonged and perplexing inflammation, with repeated CRP levels more than 20 mg/L or erythrocyte sedimentation rate more than 20 mm/h, body temperature of less than 38.3°C, and without a diagnosis after a variety of conventional diagnostic procedures.A total of 140 patients with IUO (67 men, 73 women; mean age, 64.2 years; age range, 18-87 years) underwent F-FDG PET/CT. F-FDG PET/CT was considered helpful when the imaging findings led to a diagnosis, either confirmed by histopathology, microbiological assays, clinical and imaging follow-up, or response to treatment. RESULTS: In 104 patients (73%), a final diagnosis could be established as follows: infection in 35 patients, malignancy in 18 patients, noninfectious inflammatory disease in 44 patients, and a variety of uncommon conditions in 7 patients. F-FDG PET/CT was true positive in 95 patients, true negative in 30 patients (ie, self-limiting conditions), false positive in 6 patients, and false negative in 9 patients (predominantly systemic diseases). In this population, the positive predictive value, negative predictive value, and diagnostic accuracy of F-FDG PET/CT were 94%, 77%, and 89%, respectively. In a multivariate analysis, CRP was the only independent predictor for the outcome of F-FDG PET/CT. CONCLUSIONS:F-FDG PET/CT correctly identified or excluded a causal explanation in approximately 90% of patients with IUO. However, a negative F-FDG PET/CT is indicative for a self-limiting condition only after systemic diseases are excluded by other diagnostic tests.
Authors: H Balink; S S Tan; N J G M Veeger; F Holleman; B L F van Eck-Smit; R J Bennink; H J Verberne Journal: Eur J Nucl Med Mol Imaging Date: 2015-02-06 Impact factor: 9.236