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Background Multiparametric magnetic resonance imaging (mpMRI) is widely used for the evaluation of prostate cancer and is known to have better accuracy. Gallium-68 prostate-specific membrane antigen (Ga-68 PSMA) is a radiotracer that shows high localization in prostate cancer cells. Purpose The purpose of this study was to assess the sensitivity and utility of Ga-68 PSMA positron emission tomography/computed tomography (PET/CT) in comparison with mpMRI as a noninvasive imaging technique for the initial diagnosis and locoregional staging of prostate cancer using transrectal ultrasound (TRUS)-guided biopsy as gold standard. Materials and Methods This prospective observational study conducted from August 2017 to April 2020 evaluated 60 men ( n = 60) with biopsy-proven prostate carcinoma. They underwent mpMRI and Ga-68 PSMA PET/CT scans within 14 days with TRUS biopsy being gold standard. T staging of disease, N staging of lymph nodes within the pelvis, and M staging of lesions in pelvic bones (within the imaging field of mpMRI) were compared using PSPP version 1.0.1 statistical software. Results All 60 men with a mean age of 69.9 ± 9.35 years showed Ga-68 PSMA avid disease, whereas 55 were detected by mpMRI. The sensitivity in detection of prostate lesions (with 95% confidence interval) was 99.08% for Ga-68 PSMA PET/CT and 84.40% for mpMRI. Ga-68 PSMA PET/CT detected greater number of patients with regional lymph nodal involvement (19/60) as compared with mpMRI (12/60). Ga-68 PSMA PET/CT showed PSMA avid pelvic skeletal lesions in nine patients, whereas mpMRI detected pelvic lesions in six patients. In addition, four other patients showed extrapelvic skeletal lesions on Ga-68 PSMA PET/CT. Conclusion Ga-68 PSMA PET/CT has superior sensitivity in detection of primary prostate tumor, as compared with mpMRI. Both modalities correlate well in detection of seminal vesicle involvement. Ga-68 PSMA PET/CT outperformed mpMRI in detection of lymph nodal and skeletal metastases. Hence, Ga-68 PSMA PET/CT should be considered as first-line diagnostic modality for carcinoma prostate. Summary Statement : Ga-68 PSMA PET/CT shows superior diagnostic performance than mpMRI in the evaluation of prostate cancer.
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Non-Hodgkin's lymphoma (NHL) with secondary bone marrow involvement is relatively common. However, isolated involvement of bone marrow in marginal zone type of NHL is atypical and rare. Here, we describe a patient of atypical marginal zone lymphoma with isolated bone marrow involvement who presented with weight loss and bicytopenia, where F-18 FDG PET/CT (fluorine-18-labeled fluorodeoxyglucose positron emission tomography with computed tomography) imaging played a pivotal role in establishing the diagnosis when conventional imaging modalities were unremarkable. The patient was successfully treated with systemic chemotherapy (rituximab, cyclophosphamide, prednisolone) and achieved complete remission, as demonstrated by a follow-up F-18 FDG PET/CT scan.
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Tumor-induced osteomalacia (TIO) is a rare cause of severe debilitating osteomalacia, due to hypophosphatemia. A strong clinical suspicion based on biochemical parameters can lead to the search for a culprit tumor in the body. The disease entity is more commonly caused by benign mesenchymal tumors. While many imaging modalities have been tried, it is now known that these tumors show high somatostatin receptor (SSTR) expression. Hence SSTR receptor imaging has emerged as a useful diagnostic tool. Here we present a series of TIO cases with clinical presentation and imaging characteristics.
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ErdheimâChester disease (ECD) is a rare non-Langerhans' cell histiocytic proliferative disorder of unknown origin with multisystemic predilection. It commonly affects adults in the fifth-seventh decades of life, with male preponderance, and has nonspecific clinical manifestations. Presence of characteristic radiological findings and demonstration of CD68 positive xanthogranulomatous infiltrates in histology clinches the diagnosis. Nevertheless, being a nonmalignant condition, it might be fatal due to multiorgan dysfunction. Hence, timely diagnosis and initiation of treatment with corticosteroids, immunosuppressants, or tyrosine kinase inhibitors are of paramount importance. We present a case of ECD with multisystemic involvement, who was initially evaluated for the left lung mass and treated as tuberculosis, where fluorine-18-labeled fluorodeoxyglucose positron emission tomography/computed tomography aided in targeting the metabolically active site for biopsy as well as assessing the multisystemic involvement.