Clinical Nuclear Medicine

Uptake of 18F-Fluciclovine in Paget Disease Since its recent approval by the United States Food and Drug Administration, fluciclovine PET-CT has gained widespread use for imaging of recurrent prostate cancer patients. As an amino acid–based radiotracer transported by LAT-1 and ASCT-2 transporters, fluciclovine exploits the up-regulation of amino acid transporters in malignant cells. We present a rare case of fluciclovine uptake in Paget disease in a 58-year-old man with suspected recurrent prostate cancer and asymmetric increased left hemipelvic uptake on imaging. Received for publication March 16, 2019; revision accepted May 3, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Oladunni Akin-Akintayo, MD, MPH, Division of Nuclear Medicine, Department of Radiology and Imaging Sciences, Emory University School of Medicine, 1364 Clifton Rd, Atlanta, Georgia 30322. E-mail: oakinak@emory.edu. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

18F-Fluciclovine Uptake in Celiac Ganglia: A Pitfall in Prostate Cancer PET Imaging We present 4 cases of patients who underwent 18F-fluciclovine PET for prostate cancer demonstrating physiologic uptake in the celiac ganglia, which could be mistaken for metastatic lymphadenopathy if the celiac ganglia have a nodular configuration and uptake higher than bone marrow. Uptake in celiac, cervical, and sacral ganglia has been reported previously as an important pitfall in 68Ga-PSMA-HBED-CC PET for prostate cancer. In our patients, only celiac ganglion uptake was visualized. Advances in PET scanner technology may cause physiologic uptake of 18F-fluciclovine in celiac ganglia to become more visually distinguishable from muscular uptake in adjacent diaphragmatic crura. Received for publication February 13, 2019; revision accepted May 19, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Sean Wo, MD, Department of Radiology, University of Washington, 1959 NE Pacific St, Box 357115, Seattle, WA 98195. E-mail: seanwo@uw.edu. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Focal Immunotherapy-Induced Pancreatitis Mimicking Metastasis on FDG PET/CT A 46-year-old man with metastatic lung adenocarcinoma was treated with pembrolizumab. FDG PET/CT was performed after 3 cycles of treatment and revealed a focal region of pancreatic tail enlargement with an SUVmax value of 7. Following treatment with corticosteroids and discontinuation of pembrolizumab, radiological resolution was observed, and a diagnosis of focal immunotherapy-induced pancreatitis was made. A unique spectrum of FDG-avid adverse events can develop in patients treated with immune-checkpoint inhibitors that may mimic metastatic disease. Knowledge of the radiologic features of these potential imaging pitfalls is crucial among those interpreting FDG PET/CT to allow prompt and decisive treatment. Received for publication April 29, 2019; revision accepted May 17, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Jeeban Paul Das, MD, Memorial Sloan Kettering Cancer Center, 1275 York Ave, Box 77, New York, NY 10065. E-mail: jeeban.paul.das@gmail.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Integration of 68Ga-PSMA-PET/CT in Radiotherapy Planning for Prostate Cancer Patients Purpose To assess the role of 68Gallium-labeled-prostate-specific membrane antigen PET/CT (68Ga-PSMA-PET/CT) in risk group definition and radiotherapy planning in the initially planned definitive radiotherapy (RT) for prostate cancer patients. Methods The clinical data of 191 prostate cancer patients treated with definitive intensity-modulated RT were retrospectively analyzed. All patients were initially staged with thoracoabdominal CT and bone scintigraphy, and the second staging was performed using 68Ga-PSMA-PET/CT. Both stages were evaluated for the decision making of RT and any change in RT target volumes. Results After staging with 68Ga-PSMA-PET/CT, 26 patients (13.6%) had risk group changes, 16 patients (8.4%) had an increase in risk group, and 10 patients (5.2%) had a decrease in risk group. Down-staging occurred in 22 patients (11.5%), and upstaging was observed in 30 patients (15.7%). A total of 26 patients (13.6%) had nodal stage changes. After the 68Ga-PSMA-PET/CT scans, the number of metastatic patient increased to 17 (8.9%), with 4 of them moving from oligo- to polymetastatic disease. An additional irradiation of pelvic lymphatics and metastatic site was performed in 13 patients (6.8%) and 6 patients (3.2%), respectively. The RT was aborted in 4 patients (2.1%) because of parenchymal or distant site metastasis observed in the 68Ga-PSMA-PET/CT. Conclusions We found that 68Ga-PSMA-PET/CT causes considerable migration in stage, risk group, and RT field arrangements, especially in high-risk patients regardless of the GS and baseline prostate-specific antigen values alone. 68Ga-PSMA-PET/CT seems to have a great influence on RT decision making in prostate cancer patients. Received for publication April 26, 2019; revision accepted May 19, 2019. Conflicts of interest and sources of funding: none declared. The authors are responsible for the content and writing of the manuscript. Correspondence to: Cem Onal, MD, Department of Radiation Oncology, Baskent University Faculty of Medicine, Adana Dr Turgut Noyan Research and Treatment Center, 01120 Adana, Turkey. E-mail: hcemonal@hotmail.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Prognostic Value of Maximum Standardized Uptake Value in 68Ga-Somatostatin Receptor Positron Emission Tomography for Neuroendocrine Tumors: A Systematic Review and Meta-analysis Purpose Somatostatin receptor (SSTR) PET has become a mainstay in the diagnosis of neuroendocrine tumors (NETs) and for selecting patients for SSTR-based therapy; however, no consensus has yet been reached in terms of prognosis. A systematic review and meta-analysis was performed on the prognostic value of the maximum standardized uptake value (SUVmax) for 68Ga-SSTR PET in patients with NETs. Patients and Methods We performed a systematic search using the following keywords: PET, SSTR, NET, and prognosis. The inclusion criteria were the use of 68Ga-SSTR PET as an imaging tool, studies limited to NETs, studies that reported progression-free survival (PFS) and/or overall survival (OS), and studies that included SUVmax as a prognostic parameter. The effect of SUVmax on PFS and OS was measured in terms of the hazard ratio (HR). Results Eight eligible studies with 474 patients were finally included and analyzed. The combined HR of SUVmax on PFS was 2.31 with significance (95% confidence interval [CI], 1.34–4.00; P = 0.003). The trim and fill adjusted analysis for SUVmax on PFS demonstrated the combined HR as 1.81 with significance (95% CI, 1.11–2.95; P = 0.017), as the publication bias was found (Egger P = 0.004). The combined HR of SUVmax on OS was 2.97 with significance (95% CI, 1.71–5.15; P = 0.0001), without publication bias (Egger P = 0.929). The subgroup analysis revealed that well-differentiated NETs (grade 1 or 2) on PFS showed significance (P = 0.03); however, all grades of NETs (including grade 3) on PFS did not reach significance (P = 0.11). Tumor site and type of radiotracer did not affect the prognostic value of SUVmax. Conclusions Low SUVmax of 68Ga-SSTR PET was associated with a worse prognosis for PFS and OS in patients with NETs. Well-differentiated NETs had more prognostic value compared with all grades of NETs. The SUVmax of 68Ga-SSTR PET could be used as an objective prognosis predictor. Conflicts of interest and sources of funding: none declared. Received for publication April 11, 2019; revision accepted May 18, 2019. Correspondence to: Yong-il Kim, MD, PhD, Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Republic of Korea. E-mail: kyi821209@naver.com. Supplemental digital content is available for this article. Direct URL citation appears in the printed text and is provided in the HTML and PDF versions of this article on the journal’s Web site (www.nuclearmed.com). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Isolated Involvement of Prostate Gland by Immunoglobulin G4–Related Disease Diagnosed With the Help of FDG PET/CT Immunoglobulin G4 (IgG4)–related disease is known to mimic multiple malignancies and always poses a diagnostic challenge. We report a case of a 20-year-old young man, who presented with unexplained recurrent episodes of fever and pain abdomen. 18F-FDG PET/CT revealed intense focal FDG avidity in the prostate. On further workup, he had an elevated serum IgG4 level, and a clinical diagnosis of immunoglobulin G4–related disease was kept. A follow-up FDG PET/CT after glucocorticoid therapy revealed resolution of FDG avidity in the prostate with fall in serum IgG4 levels, hence confirming a diagnosis of atypical immunoglobulin G4–related disease involving isolated prostate gland. Received for publication January 14, 2019; revision accepted May 18, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Bhagwant Rai Mittal, MD, DNB, Department of Nuclear Medicine and PET, A Block, Postgraduate Institute of Medical Education and Research, Sector 12, Chandigarh 160012, India. E-mail: brmittal@yahoo.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Thymic Tuberculosis Shown on FDG PET/CT Despite Coexisting Pulmonary Tuberculosis With No Increased FDG Activity Extrapulmonary tuberculosis could involve multiple organs. However, thymic tuberculosis is relatively rare. We report a 21-year-old man who was referred for an 18F-FDG PET/CT imaging to assess his newly detected pulmonary nodule. The images showed the pulmonary nodule had minimal activity uptake. Unexpectedly, the thymus with elevated FDG accumulation was noted. The pulmonary nodule and thymic lesion were confirmed as tuberculosis by pathology. Received for publication April 14, 2019; revision accepted May 21, 2019. Conflicts of interest and sources of funding: This work was supported by the Key Project of Hubei Province Technical Innovation Special Funding (no. 2017ACA182) and the Clinical Research Physician Program of Tongji Medical College, Huazhong University of Science and Technology (no. 5001530008). None declared to all authors. Correspondence to: Xiaoli Lan, MD, PhD, Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology No. 1277 Jiefang Ave, Wuhan 430022, China. E-mail: LXL730724@hotmail.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Calcitonin-Negative Neuroendocrine Tumor of the Thyroid on 68Ga DOTANOC PET-CT Neuroendocrine tumors (NETs) of the thyroid gland are generally considered to be derived from parafollicular endocrine or C cells and are known as medullary thyroid carcinomas. Non–calcitonin-producing NETs of the thyroid are extremely rare in occurrence and pose a significant diagnostic dilemma for the physician and pathologist. We describe a case of a 58-year-old woman who was diagnosed as having primary NET thyroid with normal calcitonin levels and 68Ga DOTANOC PET-CT scan findings which were done for initial extent evaluation of the disease. Received for publication February 19, 2019; revision accepted May 28, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Rakesh Kumar, MD, PhD, Diagnostic Nuclear Medicine Division, Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi 110029, India. E-mail: rkphulia@hotmail.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

A Prospective Head-to-Head Comparison of 18F-Fluciclovine With 68Ga-PSMA-11 in Biochemical Recurrence of Prostate Cancer in PET/CT Purpose One of the major challenges for all imaging modalities is accurate detection of prostate cancer (PCa) recurrence. Beyond the established 68Ga-PSMA, a novel promising PET tracer in PCa imaging is 18F-fluciclovine. For evaluating the advantages and disadvantages and the comparability, we conducted a prospective head-to-head comparison on 18F-fluciclovine and 68Ga-PSMA-11 in patients with biochemical recurrence of PCa. Methods 58 patients with biochemical recurrence of PCa after definitive primary therapy were included. Both scans were performed within a time window of mean 9.4 days. All scans were visually analyzed independently on a patient-, region- and lesion-based analysis. All the examinations were performed in the same medical department using identical scanners at any time. Results The overall detection rate for PCa recurrence was 79.3% in 18F-fluciclovine and 82.8% in 68Ga-PSMA-11 (P = 0.64). Local recurrence was detected in 37.9% on 18F-fluciclovine and in 27.6% on 68Ga-PSMA-11 (P = 0.03). Local pelvic lymph node recurrence was detected on 18F-fluciclovine versus 68Ga-PSMA-11 in 46.6% versus 50%, in extrapelvic lymph node metastases in 41.4% versus 51.7% and in bone metastases in 25.9% versus 36.2%. Lesion-based analysis showed identical findings in local pelvic lymph nodes in 39.7%, in extrapelvic lymph nodes in 22.4%, and in bone metastases in 13.8%. Conclusions The advantage of 18F-fluciclovine is detecting curable localized disease in close anatomical relation to the urinary bladder, whereas 68Ga-PSMA-11 fails because of accumulation of activity in the urinary bladder. 18F-fluciclovine is almost equivalent to 68Ga-PSMA-11 in detecting distant metastases of PCa recurrence. Received for publication May 22, 2019; revision accepted May 22, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Birgit Pernthaler, MD, Division of Nuclear Medicine, Department of Radiology, Medical University of Graz Auenbruggerplatz 9A, 8036 Graz, Austria. E-mail: birgit.pernthaler@medunigraz.at. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Recovery of Renal Function Under PSMA Mediated Radioligand Therapy of Advanced Metastasized Castration Resistant Prostate Cancer Radioligand therapy targeting prostate specific membrane antigen (PSMA-RLT) is becoming increasingly important in palliative care of metastasized castration resistant prostate cancer (mCRPC) as a highly effective and low toxicity therapy option. In addition to its overexpression in prostate cancer cells, PSMA is also physiologically expressed in the kidneys which is raising concerns over dose related nephrotoxicity of PSMA-RLT. We describe potential positive short-term effects of PSMA-RLT on renal function with marked recovery of a pretreatment compromised kidney. Received for publication January 22, 2019; revision accepted May 26, 2019. Conflicts of interest and sources of funding: none declared. Consent to publish: Informed consent was obtained from the individual participant included in the study. Availability of data and materials: PET/CT and scintigraphy datasets are available from the corresponding author on request. Correspondence to: Martin Ries, MD, Klinik für Nuklearmedizin, Uniklinikum des Saarlandes, Kirrberger Str., Homburg D-66421, Germany. E-mail: martin.ries@uks.eu. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.