Multiphase Iodine Contrast-Enhanced SPECT/CT Outperforms Nonenhanced SPECT/CT for Preoperative Localization of Small Parathyroid Adenomas Purpose The aim of this study was to assess the value of intravenously contrast-enhanced CT in conjunction with 99mTc-MIBI SPECT for preoperative localization of parathyroid adenoma. Methods One hundred ninety-two patients with primary hyperparathyroidism were enrolled in the study between May 2015 and May 2017. The patients underwent a preoperative “one-stop shop” examination with 99mTc-MIBI SPECT/CT by using dual time-point (10 and 90 minutes) protocol and both nonenhanced CT and contrast-enhanced CT acquisition in the arterial and venous phase, 35 and 75 seconds, respectively, after contrast medium injection start. For 149 patients, the imaging results could be correlated to those at surgery and histopathology. Results The median adenoma weight was 330 mg. The addition of contrast-enhanced CT increased the sensitivity from 81.1% to 89.9% (P = 0.003). The specificity of nonenhanced SPECT/CT was similar to contrast-enhanced CT (96.1% vs 97.9%; P = 0.077). For patients with uniglandular disease (n = 140, 94.0%), the sensitivity increased from 86.4% to 93.6% (P = 0.021) and the specificity from 96.2% to 97.9% (P = 0.118) by adding contrast-enhanced CT. In patients with multiglandular disease (n = 9, 6.0%), adding contrast-enhanced CT improved detection sensitivity from 42.1% to 63.2%. However, these patients were few and significance was not reached (P = 0.125). Conclusions In this cohort, with generally small parathyroid adenomas, the sensitivity in preoperative localization was greatly improved by adding contrast-enhanced CT to 99mTc-MIBI SPECT/CT. Received for publication April 12, 2019; revision accepted July 15, 2019. Alejandro Sanchez-Crespo and Anders Sundin contributed equally to this work. Correspondence to: Patricia Sandqvist, MD, Department of Medical Radiation Physics and Nuclear Medicine, E5:59, Karolinska University Hospital, Solna, SE-171 76 Stockholm, Sweden. E-mail: patricia.sandqvist@sll.se. Conflicts of interest and sources of funding: none declared. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study. The local ethics and radiation protection committees approved the study (Dnr: 2014/306–31/3 and Dnr: K0570–2015, respectively). Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

The Monocle Sign in FDG-PET: A Sign of Contralateral Facial Nerve Palsy We report three cases of unilateral 18F-FDG uptake in the orbicularis oculi muscle in subjects with contralateral peripheral facial nerve palsy. We argue that this asymmetric uptake pattern in fact reflects lack of metabolism on the side affected by facial nerve palsy, owing to denervation. Since the unilateral periorbital uptake resembles a monocle, we chose to call this finding the monocle sign. The monocle sign should not be confused with inflammation or tumor, but should prompt a neurological assessment for facial nerve palsy and a potential underlying disease. Received for publication May 21, 2019; revision accepted July 21, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Erika Orita, MD, PhD, Department of Nuclear Medicine, University Hospital Zurich/University of Zurich, Rämistrasse 100, 8091 Zurich, Switzerland. E-mail: Erika.Orita@usz.ch. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Head-to-Head Comparison of 18F-Prostate-Specific Membrane Antigen-1007 and 18F-Fluorocholine PET/CT in Biochemically Relapsed Prostate Cancer Purpose of the Report The aim of the study was to prospectively compare performance of 18F-fluorocholine (FCH) and 18F-prostate-specific membrane antigen (PSMA)-1007 PET/CT in patients with biochemical relapse (BCR) of prostate cancer and low prostate-specific antigen levels. Methods We prospectively enrolled 40 BCR patients after radical treatment and prostate-specific antigen levels 2.0 ng/mL or less. 18F-FCH and 18F-PSMA-1007 PET/CT imaging was performed within a mean interval of 54 ± 21 days. Scans were done 87 ± 10 and 95 ± 12 minutes after injecting 248 ± 35 and 295 ± 14 MBq of 18F-FCH and 18F-PSMA-1007, respectively. Rates of negative, equivocal, and positive scan results were compared per patient. Per lesion, findings were grouped as equivocal or highly suggestive of malignancy and then compared for their number, localization (local relapse, lymph nodes, bones), and SUVmax values. Results Positive, equivocal, and negative results were reported in 60%, 27.5%, and 12.5% of 18F-PSMA-1007 and in 5%, 37.5%, and 57.5% of 18F-FCH scans, respectively. In 70% of scans, 18F-PSMA-1007 PET/CT upgraded 18F-FCH PET/CT results. 18F-PSMA-1007 scans also showed significantly more lesions (184 vs 63, P = 0.0006). Local relapse, lymph node, and bone lesions accounted, respectively, for 9%, 58%, and 33% of 18F-PSMA-1007 and 5%, 89%, and 6% 18F-FCH of PET/CT findings. Highly suspicious lesions accounted for 74% of 18F-PSMA-1007 and 11% of 18F-FCH PET/CT findings. In 18F-PSMA-1007 PET/CT SUVmax values of highly suggestive lesions were significantly higher than in equivocal lesions (median, 3.6 vs 2.5; P < 0.00001). Conclusions In early BCR patients 18F-PSMA-1007 showed a higher detection rate than 18F-FCH PET/CT. The former also showed more lesions in total, more highly suggestive lesions and less equivocal lesions. Received for publication May 30, 2019; revision accepted July 23, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Ewa Witkowska-Patena, MD, Department of Nuclear Medicine, Military Institute of Medicine, 128 Szaserów St, 04-141 Warsaw, Poland. E-mail: ewitkowska-patena@wim.mil.pl. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Renal Pelvis Urothelial Carcinoma With Bowel Metastases Urothelial carcinoma is the fourth most common genitourinary tumor with the majority of the tumor involving the urinary bladder. Only 5% involves the renal pelvis and ureter. Metastatic urothelial carcinoma of the renal pelvis frequently involves the lymph nodes, lung, liver, bone, and peritoneum. We share rare interesting 18F-FDG PET/CT images of a 60-year-old man with metastatic urothelial carcinoma of the renal pelvis to the bowel. Received for publication June 9, 2019; revision accepted July 24, 2019. Conflicts of interest and sources of funding: none declared. The manuscript has not been published before or is not under consideration for publication anywhere else and has been approved by all co-authors. Ethical Statement: The study was approved by an institutional review board or equivalent and has been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. Informed consent: Informed consent was obtained from the patient included in the study. Correspondence to: Alex Cheen Hoe Khoo, MBBS, MMed, FANMB, Department of Nuclear Medicine, Penang Adventist Hospital, 465, Jalan Burma, 10350 George Town, Penang, Malaysia. E-mail: dr.alexkhoo@gmail.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Early Detection of Metastatic Prostate Cancer Relapse on 68Ga-PSMA-11 PET/CT in a Patient Still Exhibiting Biochemical Response Prostate cancer (PCa) treatment monitoring usually relies on prostate-specific antigen to detect disease progression or relapse. PET/CT with prostate-specific membrane antigen (PSMA) ligands has shown high accuracy in detecting metastatic PCa lesions and could help assess response to therapy. We describe herein the early relapse detection of a hormone-sensitive metastatic upfront PCa treated with docetaxel on 68Ga-PSMA-11 PET/CT before biochemical progression. PSMA PET/CT should be considered to monitor PCa response to chemotherapy to detect early relapse, regardless of prostate-specific antigen levels, increasing the chances of finding low-volume oligoprogressive disease. Received for publication July 16, 2019; revision accepted July 26, 2019. Contributions: Dr Plouznikoff followed up on the PET/CT scans, reviewed the patient's medical records, and drafted the manuscript. Dr Artigas acted as an expert consultant for the case and revised the manuscript. Dr Sideris and Dr Gil participated in the clinical follow-up of the patient. Dr Flamen revised the manuscript for important intellectual content. Conflicts of interest and sources of funding: N.P. is a recipient of a Detweiler Travelling Fellowship provided by the Royal College of Physicians and Surgeons of Canada. None declared for all other authors. Correspondence to: Nicolas Plouznikoff, MD, PhD, FRCPC, Service de Médecine Nucléaire, Centre Hospitalier de l'Université de Montréal, 1051 Rue Sanguinet, Montréal, Quebec, H2X 0C1, Canada. E-mail: nicolas.plouznikoff@umontreal.ca. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

FDG PET/CT and Ultrasound Evaluation of Breast Implant–Associated Anaplastic Large Cell Lymphoma Breast implant–associated anaplastic large cell lymphoma (BIA-ALCL) is a rare malignancy with isolated case reports of FDG uptake on FDG PET/CT. We present 4 cases of pathology-confirmed BIA-ALCL to illustrate varying presentations and imaging features of this disease process. Breast implant–associated anaplastic large cell lymphoma presents most commonly approximately 10 years after implantation of textured silicone or saline breast implants. Patients may present with breast enlargement, peri-implant effusion, a palpable breast or axillary mass, lymphadenopathy, breast skin erythema, or pain. Diagnosis of BIA-ALCL may be confirmed by sampling of peri-implant fluid or biopsy of peri-implant masses or regional lymph nodes. Received for publication May 21, 2019; revision accepted July 28, 2019. Conflicts of interest and sources of funding: M.F.C. received personal fees from Hologic, Inc, for educational speaking outside the submitted work. None declared for V.P. Correspondence to: Matthew F. Covington, MD, 510 S Kingshighway Blvd, Campus Box 8131, St Louis, MO 63110. E-mail: covington@wustl.edu; mattfcovington@gmail.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

FDG PET/CT and MRI in Primary Spinal Cord Glioblastoma Glioblastoma is the most common primary malignant tumor of the central nervous system, most of which occur in the brain. Primary spinal cord glioblastoma is extremely rare. A 47-year-old woman presented with recurrent and progressive paresthesia and paralysis of right lower extremity. MR examination revealed a marked nodular enlargement of spinal cord at the T12 level, showing heterogeneous enhancement. FDG PET/CT showed this intraspinal lesion with high FDG uptake. Imaging findings indicated a possible diagnosis of malignant neoplasm. Surgical resection was performed, and the pathologic results confirmed a primary spinal cord glioblastoma. Received for publication June 19, 2019; revision accepted July 28, 2019. Conflicts of interest and sources of funding: This study was supported by National Natural Science Foundation of China (grant no. 81471692 and grant no. 81901776), Sichuan Science and Technology Program (grant no. 2018HH0081), project funded by China Postdoctoral Science Foundation (grant No. 2019M650245), and Post-Doctor Research Project, West China Hospital, Sichuan University (grant no. 18HXBH070). None declared to all authors. Correspondence to: Anren Kuang, MD, Department of Nuclear Medicine, Laboratory of Clinical Nuclear Medicine, West China Hospital of Sichuan University, No. 37 Guoxue Alley, Chengdu 610041, People's Republic of China. E-mail: kuanganren@263.net. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

A Machine-Learning Approach Using PET-Based Radiomics to Predict the Histological Subtypes of Lung Cancer Purpose We sought to distinguish lung adenocarcinoma (ADC) from squamous cell carcinoma using a machine-learning algorithm with PET-based radiomic features. Methods A total of 396 patients with 210 ADCs and 186 squamous cell carcinomas who underwent FDG PET/CT prior to treatment were retrospectively analyzed. Four clinical features (age, sex, tumor size, and smoking status) and 40 radiomic features were investigated in terms of lung ADC subtype prediction. Radiomic features were extracted from the PET images of segmented tumors using the LIFEx package. The clinical and radiomic features were ranked, and a subset of useful features was selected based on Gini coefficient scores in terms of associations with histological class. The areas under the receiver operating characteristic curves (AUCs) of classifications afforded by several machine-learning algorithms (random forest, neural network, naive Bayes, logistic regression, and a support vector machine) were compared and validated via random sampling. Results We developed and validated a PET-based radiomic model predicting the histological subtypes of lung cancer. Sex, SUVmax, gray-level zone length nonuniformity, gray-level nonuniformity for zone, and total lesion glycolysis were the 5 best predictors of lung ADC. The logistic regression model outperformed all other classifiers (AUC = 0.859, accuracy = 0.769, F1 score = 0.774, precision = 0.804, recall = 0.746) followed by the neural network model (AUC = 0.854, accuracy = 0.772, F1 score = 0.777, precision = 0.807, recall = 0.750). Conclusions A machine-learning approach successfully identified the histological subtypes of lung cancer. A PET-based radiomic features may help clinicians improve the histopathologic diagnosis in a noninvasive manner. Received for publication June 5, 2019; revision accepted August 3, 2019. Conflicts of interest and sources of funding: This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (NRF-2016R1C1B2011583). None declared to all authors. Correspondence to: Su Jin Lee, MD, PhD, Department of Nuclear Medicine, Ajou University School of Medicine, 164, Worldcup-ro, Yeongtong-gu, Suwon 16499, Republic of Korea. E-mail: suesj202@ajou.ac.kr. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Incidental Detection of a Giant Fecaloma on 18F-FDG PET/CT Fecal retention can be exacerbated in older patients, bedridden patients, as well as those receiving opioids analgesics or anticholinergic medications. It can lead to impaction, which can have serious consequences, sometimes even requiring surgical intervention. We describe herein the incidental detection of a giant hypometabolic fecaloma on PET/CT with 18F-FDG during the initial staging of a patient with osteosarcoma using opioids for pain management. Received for publication July 18, 2019; revision accepted July 27, 2019. Author Contributions: N.P. read the PET/CT, followed up on the case, and wrote the manuscript. Conflicts of interest and sources of funding: none declared. Correspondence to: Nicolas Plouznikoff, MD, PhD, FRCPC, Service de Médecine nucléaire, Centre Hospitalier de l'Université de Montréal (CHUM), 1051 rue Sanguinet, Montréal, Quebec, Canada H2X 0C1. E-mail: nicolas.plouznikoff@umontreal.ca. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Burkitt’s Lymphoma Involving Multiple Hormone-Producing Organs on FDG PET/CT Lymphoma involving many different organs can be occasionally observed. However, lymphoma involvement of multiple hormone-producing organs is rare. In this report, we described our FDG PET/CT findings in a 21-year-old man whose Burkitt's lymphoma involved not only lymph nodes, the spleen, the brain, and the bones, but also 4 organs in the endocrine system, including the thyroid, right adrenal, the pancreas, and the right testicle. Received for publication July 15, 2019; revision accepted August 4, 2019. Conflicts of interest and sources of funding: none declared. Correspondence to: Zhe Wen, MD, PhD, Department of Nuclear Medicine, Beijing Shijitan Hospital, Capital Medical University, No. 10 Tieyi Rd, Haidian District, Beijing, 100038, China. E-mail: wenzhedr@foxmail.com. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.