Yousif A. Lucinian

Purpose Data on the use of fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in non-granulomatous myocarditis are limited, and no study has evaluated the diagnostic performance of combined FDG-PET and rest myocardial perfusion imaging (rMPI). Methods We conducted a multicenter prospective observational feasibility study of patients who underwent combined FDG-PET/CT with rMPI as well as cardiac magnetic resonance (CMR) for suspected myocarditis. When available, endomyocardial biopsy (EMB) established the diagnosis according to consensus criteria. Otherwise, the final adjudicated clinical diagnosis served as the reference standard. All patients had a minimum follow-up of 12 months following PET imaging. Results Twenty-five patients were included, of whom 18 (72%) were diagnosed with myocarditis. FDG-PET and rMPI demonstrated a sensitivity/specificity of 61%/100%, and 59%/71%, respectively. Inter-reader agreement for FDG-PET was excellent (κ = 0.84, 95% CI 0.62–1.00). The combination of FDG-PET and rMPI yielded a sensitivity of 82% (95% CI: 50–93%) and a specificity of 71% (95% CI: 29–96%). Late gadolinium enhancement (LGE), excluding isolated subendocardial patterns, showed a sensitivity/specificity of 72%/57%. Spatial agreement between rMPI perfusion defects and LGE on CMR was modest (κ = 0.35, 95%CI: 0.23–0.47). Conclusion Combining FDG-PET with rMPI may be a feasible imaging modality for detecting non-granulomatous myocarditis by capturing both inflammatory and fibrotic components across different disease stages.

We present the case of a 67-year-old man undergoing immunosuppressive therapy with known pulmonary blastomycosis who presented with knee swelling and fever. FDG-PET/CT performed to exclude septic arthritis revealed increased uptake within the right epididymis and multiple osteoarticular, cutaneous, and subcutaneous sites. Cultures obtained from bronchoalveolar lavage, urine, right knee arthrocentesis, and subcutaneous tissue all demonstrated Blastomyces dermatitidis, compatible with disseminated blastomycosis (DB). To the best of our knowledge, this is the first case of DB in a human subject documented by FDG-PET. This case showcases FDG-PET as a potentially sensitive imaging modality in staging blastomycosis multiorgan involvement, aiding in identifying culture sites by revealing clinically and radiologically unsuspected foci of infection.