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Background: Soft-tissue attenuation remains a major limitation of SPECT-MPI which interferes with the diagnosis of CAD. The current study aims to evaluate the pattern of attenuation artifacts in supine and semi-reclining positions on CZT cardiac camera and their interaction with gender, BMI and stress protocols., Methods: We prospectively analysed 150 patients acquired in supine and semi-reclining positions on CZT camera. The images were evaluated for severity and extent of defect using 17-segment model. An additional CT scan was acquired to generate AC image in the first 50 patients studied to assist investigator learning for comparison of artifact vs true defects in the two SPECT systems. The defects present in one position or showing change in severity within two positions were considered as positional artifacts and further validated using CTAC supine image., Results: In overall analysis, higher extent and severity of positional artifacts were observed more in semi-reclining position affecting the apex, apico-inferior, inferolateral and inferoseptal segments. Females showed more positional artifacts than males with inferior wall attenuation in the semireclining position and anterior wall attenuation in the supine position. A positive correlation of the extent and severity of positional artifacts was noted with an increasing BMI. In patients with BMI > 30, mid inferior and inferolateral segments were most affected followed by anterior wall segments. Highest correction of artifactual perfusion defects by CTAC was noted in inferior wall followed by inferolateral segments., Conclusion: The incidence of positional artifacts was greater in semi-reclining position in females, higher BMI groups and adenosine stress subsets. Knowledge of the pattern of positional artifacts appears to be a reliable alternative of CTAC for correct interpretation of myocardial perfusion images., (© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.)

Background Transrectal US-guided biopsy with or without MRI fusion is performed for diagnosing prostate cancer (PCa) but has limitations. Gallium 68 ( 68 Ga) prostate-specific membrane antigen (PSMA) PET/CT-guided targeted biopsy has the potential to improve diagnostic yield of PCa. Purpose To evaluate the safety and diagnostic yield of 68 Ga PSMA PET/CT-guided, robotic-arm assisted transgluteal prostatic biopsy. Materials and Methods In this single-center nonrandomized prospective trial, participants with a clinical suspicion of PCa (serum prostate-specific antigen level > 4 ng/mL) were recruited from January 2019 to September 2020. After whole-body 68 Ga PSMA PET/CT, participants with PSMA-avid intraprostatic lesions underwent PET-guided transgluteal biopsy by using an automated robotic arm. To assess safety and diagnostic yield, procedure-related complications and histopathologic results were documented. Pain during the procedure was scored by a visual analog scale. Descriptive statistics were applied; qualitative variables were reported in percentages. Results Seventy-eight participants (mean age, 66 years ± 7 [standard deviation]; 36 participants [46%] with prior negative results at transrectal US-guided biopsy) were enrolled. Fifty-six (72%) participants had PSMA-avid lesions (prior negative results at transrectal US-guided biopsy in 22 of 56 [39%]) and underwent targeted biopsy. PCa was confirmed in 54 of 56 (96%) participants, and clinically significant PCa (Gleason score ≥ 7) was confirmed in 24 of 54 (44%). Two participants had nonrepresentative samples that required rebiopsy. All participants experienced pain during the procedure, mild (median visual analog scale score, 1; interquartile range, 1-2) in 36 of 56 (64%) and moderate (median visual analog scale score, 5; interquartile range, 5-6) in 20 of 56 (36%). Postprocedure complications were noted in five of 56 (9%) participants and were minor (hematuria, four participants; hematospermia, one participant; and gluteal pain, two participants). No participant developed a postprocedural infection. Conclusion Transgluteal prostate-specific membrane antigen (PSMA) PET/CT-guided, robotic-targeted prostatic biopsy is safe with a high diagnostic yield of prostate cancer for PSMA-avid lesions. Clinical trial registration no. NCT05022576 © RSNA, 2022.

Aims: 99mTc-labeled RBC-equilibrium radionuclide angiocardiography (ERNA) is done in transfusion-dependent beta-thalassemia major (β-TM) patients routinely for cardiac dysfunction. This prospective study aimed at evaluating the potential of ERNA in demonstrating the bone marrow hyperplasia as an adjunct biomarker for monitoring the adequacy of blood transfusions in transfusion-dependent β-TM patients., Materials and Methods: One hundred and twenty-six patients of β-TM (study group) and 30 nonthalassemic patients (control) underwent ERNA study with an additional whole-body imaging. We quantitated the normalized bone marrow tracer uptake (due to marrow hyperplasia) and hepatic tracer uptake (indicator of hepatic perfusion) in both the groups on whole-body imaging. Liver and myocardial iron deposition were evaluated with T2* MRI in the thalassemic group., Results: β-TM group showed significantly increased mean normalized marrow count (MN) compared to the control group (P < 0.001) reflecting peripheral marrow hyperplasia (indirect marker for blood transfusion inadequacy). The hematological parameters in the study group showed a negative correlation with MN, without such correlation in the control group. The study group showed greater derangement in hepatic perfusion with significantly less mean normalized hepatic tracer uptake (HN) compared to the control group. Hepatic iron deposition (evaluated with T2* MRI) also showed a negative correlation with hepatic perfusion parameter (HN) assessed by ERNA, though myocardial iron deposition did not show any significant correlation with cardiac systolic/diastolic parameters evaluated by ERNA in the study group., Conclusion: ERNA study with these novel parameters (MN and HN) may have the potential to assess peripheral marrow hyperplasia and derangement in hepatic perfusion in transfusion-dependent β-TM., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Liver radiotracer activity interfering with the inferior myocardial wall in a patient undergoing myocardial perfusion imaging (MPI) with 99m Tc-Sestamibi is a known pitfall. We report a patient with pituitary macroadenoma who was subjected to stress-MPI study for pre-anesthetic clearance. The post-stress raw image showed the liver radiotracer activity in close approximation to the anteroseptal wall of the left ventricular myocardium, secondary to right hemi-diaphragmatic eventration.

Prostate cancer (PCa) is one of the major causes of death due to cancer in men. Conventional imaging modalities such as magnetic resonance imaging (MRI) provide locoregional status, but fall short in identifying distant metastasis. C-11 choline F-18 fluorocholine (F-18 FCH) has been shown to be useful in imaging of PCa. The present prospective study evaluates and compares the role of F-18 FCH positron emission tomography-computed tomography (PET-CT) with locoregional MRI and whole-body bone scintigraphy in PCa patients for initial staging and recurrence evaluation. This study included a total of 50 patients. Tc-99m skeletal scintigraphy, F-18 FCH PET-CT, and diffusion-weighted MRI of the pelvic region were performed within a span of 2-3 weeks of each other, in random order. For the primary site, core biopsy findings of the lesion were considered as gold standard. The kappa test was used to measure agreement between bone scintigraphy, F-18 FCH, and MRI. For comparing Tc-99m bone scintigraphy, F-18 FCH, and MRI, McNemar's test was applied. F-18 FCH PET-CT and MRI were able to detect primary lesion in all initial staging patients. The sensitivity and specificity of F-18 FCH PET-CT versus MRI were found to be 92.8% versus 89.2% and 100 versus 80%, respectively, for the recurrence at the primary site. A total of 55 bony lesions at distant sites were detected on F-18 FCH PET-CT in comparison to 43 bone lesions on whole-body bone scintigraphy. F-18 FCH PET/CT also detected additional lung lesions in 2 patients and abdominal lymph nodes in 12 patients. F-18 FCH PET-CT could detect primary lesions, local metastasis, bone metastasis, and distant metastasis in a single study and is also a useful modality in recurrence evaluation in PCa patients., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 World Journal of Nuclear Medicine.)

PSMA-based radioligand therapies have shown the beneficial effect in metastatic castrate-resistant prostate cancer (mCRPC) patients when they become refectory to the established treatments with associated potential toxicities and high mortality rate. Ac-PSMA therapy is known to be remarkably effective in substantially pretreated mCRPC patients. However, posttherapy imaging is usually not performed as alpha emitters are really difficult to image. We presents a patient of mCRPC treated with Ac-PSMA-617, and his posttherapy whole-body scans acquired by using 3 different photopeaks (78, 218, and 440 keV) fairly demonstrated the tracer's distribution and the efficacy of targeted alpha therapy.

Ga-labeled prostate-specific membrane antigen (PSMA) ligand PET/CT is a rapidly evolving imaging modality for prostate cancer. However, with the widespread use of Ga-PSMA PET/CT, various reports of nonprostatic uptake of Ga-PSMA in both benign and malignant lesions have also appeared. We report a recently diagnosed case of prostate cancer demonstrating diffuse Ga-PSMA expression in both the lobes of thyroid gland, which on further clinical and biochemical investigations was established as hypothyroidism.

Purpose: The purpose of this prospective study was to evaluate the feasibility of positron emission tomography/computed tomography (PET/CT)-guided biopsy of Ga-68 avid lesions using an automated robotic arm and determine the diagnostic yield of this technique., Material and Methods: Patients who underwent Ga-68 labelled tracers imaging followed by PET/CT-guided biopsies of tracer-avid lesions were prospectively included. Biopsies were performed using a dedicated automated-robotic-arm assisted PET/CT-guided biopsy device on the same-day of diagnostic PET/CT-imaging. The tissue samples were retrieved after confirming the position of needle-tip in the target lesion. Procedure-related complications and radiation exposure of the interventionist were recorded. Histopathological reports were reviewed for diagnostic yield., Results: A total of 25 patients (19 men, six women) with a mean age of 50.8±17.3 (SD) years (range: 17-83 years) were included. The biopsies were performed after PET/CT using Ga-68 DOTANOC (n=16) or Ga-68 PSMA (n=8) and Ga-68 chemokine-analogue (n=1). The biopsy samples were obtained from the liver (n=9), bone (n=8), lymph-nodes (n=3), lung (n=1), pancreas (n=1), anterior mediastinal lesion (n=1), peritoneal-deposit (n=1) and thigh-lesion (n=1). No immediate or delayed procedure-related complications were documented in any patient. PET/CT-guided molecular sampling was technically successful in all the patients. Histopathology revealed malignancies in all the biopsied specimens without the need for repeat sampling or further invasive-diagnostic workup, with a diagnostic yield of 100%. The estimated absorbed-radiation dose was 566.7μSv/year for the interventionist., Conclusion: PET/CT-guided molecular biopsy using Ga-68 labelled radiotracers is feasible and can be performed safely and accurately with a high-diagnostic yield. It is helpful in accurately staging the disease when tracer-avid isolated distant lesion evident on imaging and highly practical in patients with previous inconclusive sampling., (Copyright © 2019 Société française de radiologie. Published by Elsevier Masson SAS. All rights reserved.)

Extraocular muscles show physiologic radiotracer uptake on F-FDG PET/CT as is encountered in most routine scans. Certain pathologies can cause palsy of one or more of the extraocular muscles, leading to hypometabolism on F-FDG PET/CT. We present a case with a classical finding of unilateral hypometabolism of the lateral rectus muscle, disrupting the "V" sign formed due to physiologic uptake. The patient had presented with the complaint of diplopia and was being evaluated further to rule out the possibility of inflammatory/granulomatous infectious etiopathogenesis leading to compression of the abducens nerve resulting in lateral rectus palsy.

Purpose: Minimally invasive parathyroid carcinoma (MIPC) is clinically and biochemically comparable with parathyroid adenoma (PA) though histopathologically differ from PA. MIPC is an intermediate of PA and parathyroid carcinoma (PC). In literature, there is no definite criterion to diagnose MIPC. Our aim was to evaluate and characterize the imaging and biochemical parameters with histological characteristics of MIPC., Methodology: Ten patients with MIPC were recruited from (single centre) Indian PHPT registry (www.indianphptregistry.com) from January 2014 to July 2018. Clinical, biochemical, imaging and histological features of MIPC patients were reviewed., Results: The mean age of MIPC patients (n = 10; 3 males) was 39.9 ± 11.3 years (range: 17-50). All patients had an elevated preoperative parathyroid hormone (iPTH) level ranging from 427 to 2138 pg/mL (median: 1328). MIBI scan showed intensely avid and enlarged parathyroid tumours in all patients; LIPT in 6, RIPT in 3 and ectopic mediastinal in 1 with mean size of the tumours was 2.8 ± 1.1 cm. The mean of maximum standardized uptake value (SUVmax) of MIPC in F-18 fluorocholine PET/CT was 6.7 ± 1.1 (range 6.0-8.3). The mean tumour weight was 12 ± 9.5 g (range: 1.09-28). All MIPC patients had identified capsular invasion in 80% and vascular invasion in 50% only but there was no local invasion, lymph nodal or distant metastasis. The mean Ki-67 labelling index was 3.2 ± 2.7 (range 1.1-10)., Conclusion: The study concluded that MIPC patients are less aggressive (on the basis of imaging and histopathological findings) and should be differentiated from parathyroid adenoma and carcinoma., (© 2019 John Wiley & Sons Ltd.)

Skeletal muscle uptake of F-FDG can result from a variety of physiologic and pathologic conditions. It is important for the physician to interpret these uptake patterns in the correct context to avoid a misdiagnosis. We present a case of a 36-year-old man with progressive, repeated episodes of regurgitation who was diagnosed with adenocarcinoma of the stomach. F-FDG PET/CT showed increased tracer uptake in the primary tumor and in the intercostal and sternocleidomastoid muscles. The pattern of tracer uptake along with the clinical history and examination of the patient helped differentiate a physiologic variant from a pathologic cause.

Although 18 F-fluorodeoxyglucose (FDG) is the most extensively used tracer in oncological positron emission tomography/computed tomography (PET/CT) studies, various physiological as well as benign pathological conditions are known to cause false-positive results. This report describes 18 F-FDG PET/CT done in an elderly man with primary hepatocellular carcinoma, revealing a metastasis mimicking lesion in the left inguinal canal, which was identified as the herniated portion of the urinary bladder. Though rare, bladder herniation, especially with a narrow neck, can be a pitfall in the evaluation for metastatic disease. The study also highlights the utility of delayed imaging in the evaluation of pelvic pathology., Competing Interests: There are no conflicts of interest.

We present a case of biopsy-proven prostatic adenocarcinoma with a tracer-avid left paravertebral location at D4 to D5 vertebrae, suggestive of metastasis. However, in view of uncommon location of single-site metastasis at paravertebral region with no tracer-avid regional lymphadenopathy, image-guided biopsy was done, which was suggestive of paraganglioma. Ga-PSMA is known to have variable tracer avidity in multiple nonprostatic benign as well as malignant lesions, and our case adds to the list of nonspecific uptake by this once considered "specific" to prostate PET radiotracer.

Ga-DOTANOC PET/CT is well documented in evaluation of well-differentiated neuroendocrine tumors and in other lesions with somatostatin receptor expression such as pheochromocytoma, paraganglioma, neuroblastoma, meningioma, and mesenchymal tumors causing oncogenic osteomalacia. Causes of interpretative pitfalls include prominent pancreatic uncinate process activity, inflammation, osteoblastic activity (degenerative bone disease/fracture/vertebral hemangioma), splenunculi/splenosis, and others. We present a case of extraskeletal paravertebral lesion detected in a known case of breast cancer with increased Ga-DOTANOC uptake later proved to be hemangioma. This is a novel finding and should be kept as a rare benign differential in evaluation of lesions with somatostatin receptor expression.

We present a case of a 22-year-old man with history of allogenic renal transplantation on immunosuppression, who underwent F-FDG-PET/CT to characterize a lesion in the transplanted kidney on ultrasonogram and contrast-enhanced computed tomography imaging. PET/CT revealed FDG avid lesion in the transplanted kidney and mural thickening involving the distal ileum, ileocecal junction, and ileocolic lymph nodes. Subsequent histopathological examination from the renal lesion revealed renal cell carcinoma in the transplanted kidney. Additionally, endoscopic biopsy from the ileal thickening revealed granulomatous inflammation, suggesting tuberculosis, which was missed on both ultrasonogram and contrast-enhanced CT imaging.

We present a case of endometrioid carcinoma metastasis in the bladder mimicking as the second primary of urinary bladder on 18 F-fluorodeoxyglucose positron-emission tomography/computed tomography ( 18 F-FDG PET/CT). The presentations of bladder lesions on 18 F-FDG PET/CT are varied, and rare presentations of common malignancies can pose a significant diagnostic challenge as in the index case and highlight the importance of histopathological examination to confirm any unusual FDG uptake confounding the diagnosis., Competing Interests: There are no conflicts of interest.

Purpose: To evaluate the feasibility and diagnostic performance of 18 F-FDG PET/CT-guided biopsy of abdominal and pelvic lesions with automated robotic arm (ARA) assistance., Methods: This prospective study included 114 patients (75 men, 39 women; mean age 51.3 ± 14.7 years, range: 18-90 years) who underwent PET/CT-guided biopsy of FDG-avid abdominal and pelvic lesions from October 2014 to December 2017. Of these patients, 54 had a prior inconclusive CT-guided biopsy. The biopsies were done with ARA assistance, and a real-time sample was obtained after confirming the position of the needle tip within the target lesion on PET/CT. Histopathology reports were reviewed to evaluate the diagnostic performance of the procedure. Clinical or imaging follow-up was done to confirm negative results., Results: The lesions were successfully targeted in 110 of the 114 patients (96.5%) and yielded a pathological diagnosis. Pathological diagnoses were confirmed in 50 of the 54 patients with a prior inconclusive biopsy. Of the 110 lesions, 82 were malignant, 20 were benign, and 8 showed minimal residual FDG uptake at the end of treatment and had no active disease even on clinical and imaging follow-up of at least 3 months. Findings were true-positive in 102 lesions, false-positive in none, true-negative in eight and false-negative in four. The procedure showed sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 96.2%, 100%, 100%, 66.7 and 96.5%, respectively. No immediate complications or delayed life-threatening events were observed., Conclusion: Percutaneous biopsy of metabolically active abdominal and pelvic lesions with ARA assistance is a technically feasible, safe and accurate method for pathological diagnosis with high diagnostic performance. PET-guided biopsy is highly practical and useful in patients, especially in those with a previous inconclusive biopsy.

Adenoid cystic carcinoma of the buccal mucosa has an increased propensity for recurrence and distant metastases. Due to the poor prognosis at late detection of distant metastases, it is advisable to keep a close follow-up. In the present case, 18 F-fluorodeoxyglucose positron emission tomography/computed tomography proved invaluable in the comprehensive workup of the patient, including detection of local recurrence, distant metastases, and in assessing treatment response., Competing Interests: There are no conflicts of interest.

Purpose: Male breast cancer (MBC) is a rare malignancy, with recurrence being one of the main adverse predictors for prognosis. The aim of the study was to evaluate the diagnostic and predictive value of fluorine-18-fluorodeoxyglucose (F-FDG) PET/CT in the setting of suspected recurrence of MBC., Patients and Methods: Retrospective analysis of PET/CT findings was performed in 23 previously treated, histologically proven patients with MBC (mean age: 59.3±10.9 years; range: 36-79 years) with suspected recurrence. Kaplan-Meier disease-specific survival analysis was made with respect to histological, hormonal profile as well as PET/CT findings., Results: Of the 23 patients, 19 (82.6%) showed recurrence. Recurrence at primary site with/without regional/distant site recurrence was seen in 12 (52.2%) patients. Only metastatic recurrence without primary site was seen in seven (30.4%) patients. Bone was the most common site of distant metastasis (14/23) followed by lungs (9/23), liver (4/23), brain (2/23), and adrenal (1/23). No recurrence (regional/distant) was noted in 4/23 (17.3%) patients; however, three of them had F-FDG-avid soft tissue lesions in esophagus, rectum and tongue, correspondingly, confirmed as second primaries with histopathology. Disease-specific survival analysis yielded nodal (P=0.01) as well as distant metastases (P=0.02) as the main survival predictors on PET/CT. Lung (P=0.001), followed by liver (P=0.009), and skeletal (P=0.01) metastases were the most adverse survival predictive factors., Conclusion: F-FDG PET/CT showed good diagnostic and prognostic utility in recurrent MBC. It was better than bone scan in evaluation of skeletal metastases. Most importantly, F-FDG PET/CT helped in early detection of second malignancy and their clinical management in studied patients.

Groove pancreatitis is a rare form of chronic pancreatitis that affects the groove area adjacent to the second part of the duodenum. Clinical and biochemical features often overlap with other subsets of chronic pancreatitis, while the imaging features resemble that of carcinoma of the head of pancreas. We present a 38-year-old man with abdominal pain, nausea, vomiting, and loss of weight who underwent 18 F-FDG PET/CT to rule out a pancreatic malignancy. PET/CT imaging features of groove pancreatitis are distinct from the other subsets of chronic pancreatitis, such as alcoholic and autoimmune pancreatitis, and helpful in the diagnosis and planning further management of the patient., Competing Interests: Ashwin Singh Parihar, Bhagwant Rai Mittal, Shelvin Kumar Vadi, Apurva Sood, Rajender Kumar, and Usha Dutta declare that they have no conflict of interest.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. For this type of study, formal consent is not required.The institutional review board of our institute approved this retrospective study, and the requirement to obtain informed consent was waived.

We present the case of a 36-year-old woman who underwent 18 F-FDG PET/CT with suspicion of a primary breast malignancy. However, PET/CT detected an occult renal cell carcinoma with metastases to the thyroid, breast, lungs and lymph nodes. Thyroid and breast metastases are atypical metastatic sites of renal cell carcinoma. Breast metastases from extra mammary tissue are extremely rare, more so from renal cell carcinoma. Histopathologic confirmation of the breast lesions is imperative to avoid unnecessary mastectomy and imaging can help in raising the suspicion of metastatic involvement versus primary breast malignancy., Competing Interests: Ashwin Singh Parihar, Bhagwant Rai Mittal, Shelvin Kumar Vadi, Rajender Kumar, Kaniyappan Nambiyar, Bishan Radotra, and Lileswar Kaman declare that they have no conflict of interest.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. For this type of study formal consent is not required.The institutional review board of our institute approved this retrospective study, and the requirement to obtain informed consent was waived.

Extraskeletal osteosarcoma is a rare, high-grade soft tissue malignancy, accounting for approximately 1% of all soft tissue sarcomas. Despite the histologic resemblance to osteogenic osteosarcoma, it is considered as a distinct entity because of the differences in clinical behavior and response to treatment. Hence, imaging plays a vital role in establishing the nonskeletal origin of the tumor, differentiating it from osteogenic osteosarcoma. We present F-FDG PET/CT findings in a case of isolated primary extraskeletal osteosarcoma confirmed on histopathology.

Immunoglobulin G4-related disease (IgG4-RD) with multisystem involvement is known to mimic various malignancies and can be diagnosed with high clinical suspicion. We hereby report an atypical case of IgG4-RD, who presented as an inflammatory pseudotumor resembling gall bladder malignancy with hepatic, omental, and subcutaneous involvement. The characteristic tracer uptake pattern described on FDG PET/CT may not be always present in IgG4-RD, especially in the setting of postabdominal surgery. FDG PET/CT revealed the disease progression despite glucocorticoids and aided in response evaluation after second-line drug, rituximab.

Ectopic Cushing syndrome constitutes approximately 10% of all patients with Cushing syndrome. The clinical features of hypercortisolism result from elevated levels of adrenocorticotropic hormone produced by a tumor. The present case presented with clinical and biochemical parameters suggestive of Cushing syndrome with normal pituitary and adrenals on imaging. Ga-DOTANOC PET/CT done to localize an ectopic adrenocorticotropic hormone-producing tumor revealed metastatic medullary carcinoma of the thyroid as the culprit lesion.

18F fluorodeoxyglucose positron-emission tomography/computed tomography ( 18 F-FDG PET/CT) is a standard imaging tool in staging as well as response evaluation for lymphoma. Here, we present a young male with extensive extranodal lymphoma with cardiac involvement which presented as diffuse myocardial lesion mimicking hypertrophic obstructive cardiomyopathy. 18 F-FDG PET/CT helped in the staging by revealing multiple systemic involvements. Interim PET after three cycles of chemotherapy showed a complete metabolic response to therapy in all the extranodal sites including the cardiac involvement, thus retrospectively confirming the lymphomatous involvement. Previous literature also conforms to the superior role of 18 F-FDG PET/CT in the clinical management of extensive extranodal lymphoma., Competing Interests: There are no conflicts of interest.

Sclerosing encapsulating peritonitis also called as abdominal cocoon is a less understood condition mostly due to idiopathic causes and sometimes secondary to tuberculosis or peritoneal dialysis. This report describes the typical features of "abdominal cocoon" on F-FDG PET/CT in a young woman, which was later diagnosed to be secondary to tuberculosis. Because the early features of this unusual entity are often nonspecific, high clinical suspicion along with understanding of the typical radiological/PET/CT features of this intriguing entity may guide the physician in ruling out the secondary treatable causes like tuberculosis, as noted in the index case.

Ga-PSMA-HBED-CC PET/CT has proven to be a useful modality in patients with prostate carcinoma, especially in those with suspected recurrence and in detection of locoregional and distant metastases. However, with expanding use of this tracer, several recent reports of in vivo expression of PSMA in nonprostatic benign and malignant entities have been published. We report a patient with PSMA-avid synchronous urinary bladder paraganglioma and metastatic prostate carcinoma.

Here we report a 31-year-old man with a peri-ampullary neuroendocrine tumor (NET), who underwent Ga DOTANOC-PET/CT for recurrence evaluation, which revealed isolated metastatic lesion in liver segment V. He underwent trans-arterial radio-embolization (TARE) of the isolated hepatic metastasis with Rhenium-microspheres in a lipiodol matrix. The second Ga DOTANOC-PET/CT was performed one month after the TARE therapy revealed resolution of the tracer uptake with good retention of the lipiodol complex replacing the metastasis suggesting a complete response.

Insulinomas are the most common functioning pancreatic neuroendocrine tumors and the leading cause of persistent hypoglycemia with hyperinsulinemia in adults. Glucagon-like-peptide-1 (GLP) receptor analogs are the latest agents being used in the detection of insulinomas, with initial reports suggesting high sensitivity due to universal GLP1 receptor expression on these tumors. PET/CT imaging in this patient using Ga DOTA-Exendin, a GLP receptor analog, proved useful for accurate localization of the culprit lesion, aiding in the definitive management of the patient.

18 F-Fluorodeoxyglucose-positron emission tomography/computed tomography ( 18 FDG PET/CT) has shown an increasing role in the evaluation of urinary bladder cancer, though benign pathological processes of the urinary bladder can also result in increased FDG uptake. Leiomyomas of urinary bladder are benign mesenchymal neoplasms and a very rare bladder tumor comprising <0.5% of all bladder tumors. Here, we present the low-grade 18 FDG uptake in urinary bladder leiomyoma on PET/CT done for the clinical suspicion of bladder cancer, which can be a rare differential for bladder carcinoma., Competing Interests: There are no conflicts of interest.

IgG4-related disease (IgG4-RD) continues to be a diagnostic challenge and a great mimicker of malignancies. We report here a case of young man who presented with subacute intestinal obstruction with initial imaging and clinical features suggestive of carcinoma colon. F-FDG PET/CT showed diffuse peritoneal carcinomatosis pattern typically seen with abdominal malignancies. However, the histopathology and the raised IgG4 levels diagnosed it to be IgG4-RD. Although F-FDG PET/CT has typical patterns corresponding to the multisystemic involvement of IgG4-RD, the index case did not show any such findings.

Neoplasms arising from the urachus are extremely rare. We present a case of a young woman with mild abdominal pain and a palpable swelling in the mid abdomen with incidental detection of a subumbilical mass. Repeated fine-needle aspiration cytology failed to reveal the true nature of the lesion. F-FDG PET/CT showed tracer uptake in the cranial end of urachal remnant lesion. Core biopsy from the site with maximal FDG uptake turned out to be lymphomatous involvement in urachus, which is extremely rare and previously unreported.

Gallium-prostate-specific membrane antigen (Ga-PSMA) is well established in the imaging of prostate cancer (PC). Here, we report a case of castration-resistant PC who underwent Ga-PSMA PET/CT for recurrence evaluation, which revealed metastatic lesions in distant lymph nodes and additionally an unusual metastatic deposit in the inguinal canal. The second Ga-PSMA PET/CT done after oral hormonal therapy yielded a favorable response. This pattern of distant metastatic spread is a rare presentation of PC, and PSMA PET/CT revealed the unusual metastasis in the inguinal canal with a timely therapy culminating in favorable disease response.

Ga-prostate-specific membrane antigen (PSMA) ligand is a well-known tracer used in prostate cancer. Nevertheless, there are reports of unusual Ga-PSMA uptake in variety of benign lesions. We report a case of prostate cancer in which Ga-PSMA PET/CT revealed tracer avidity in the enhancing walls of cystic lesions in the brain consistent with the features of neurocysticercosis. The uptake of Ga-PSMA in neurocysticercosis is not known and may be attributed to angiogenesis occurring at the periphery of these lesions.

An 85-year-old man with prostate cancer for metastatic workup underwent Gallium Prostate-Specific Membrane Antigen (Ga-PSMA) PET/CT (Ga-PSMA PET/CT), which revealed unusual tracer uptake in the shaft and glans of penis as well as multiple systemic metastases in liver, skeletal, and lymph nodes. The penile lesion was proved to be metastatic adenocarcinoma from prostate on fine needle aspiration cytology. The patient underwent Lutetium (Lu)-labeled PSMA radioligand therapy, which also revealed diffuse tracer uptake in the penile shaft as well as other metastatic sites.

Purpose: The aim of the study was to analyze the diagnostic and prognostic utility of F-FDG PET/CT to predict the disease-specific survival (DSS) with FDG uptake and tumor grade in recurrent chondrosarcoma., Methods: Retrospective analysis of FDG PET/CT findings in 31 previously treated patients (46 studies) with mean follow-up period of 40.7 ± 23.9 months (range, 3-77 months) from the date of first PET/CT study was done. Kaplan-Meier DSS analysis was made with respect to tumor grade, FDG uptake at the recurrent primary sites, and a combination of grade and FDG uptake as parameters., Results: Recurrence (local and distant) was shown in 28 (60.8%) of 46 FDG PET/CT studies with sensitivity and specificity of 88.9% and 78.9%, respectively. The median SUVmax at the recurrent primary sites differed significantly (P = 0.008) among 3 tumor grade groups, with higher median SUVmax in higher grades. There was significant difference in median SUVmax among different grade groups except between grade II and grade III. Recurrent primary site SUVmax cutoff at 6.15 derived from the receiver operating characteristic curve yielded significant difference (P < 0.001) in mean DSS time. Significant difference in survival was noted between 3 different tumor grade groups (P = 0.016). The combination of SUVmax and grade improved the survival prediction than with grade alone., Conclusions: In recurrent chondrosarcoma, the recurrent primary site FDG uptake and grade were found to be reliable prognostic factors with respect to DSS. PET/CT in recurrence setting has the potential to predict tumor grade and survival and may assist in clinical management.

The complementary anatomical and functional information provided by hybrid imaging with single-photon emission computed tomography-CT (SPECT-CT) is a very useful imaging tool in selected cases where anatomical information is lacking as in the scenario of dynamic renal scintigraphy. The authors present a case of a 5-year-old male child with symptoms suggestive of cutis laxa with urinary tract infection. The child underwent dynamic renal scintigraphy with Tc99m ethylene dicysteine for cortical function and drainage assessment. Hybrid SPECT/CT proved valuable in the child in identification of the bilateral gross urinary bladder diverticulae., Competing Interests: There are no conflicts of interest.

A 71-year-old male patient with urothelial carcinoma of the bladder was referred for 99m Tc-methylene diphosphonate bone scintigraphy to assess for skeletal metastasis. While the bone scan showed no abnormal skeletal uptake, tracer activity was detected in the extrarenal region of the left renal fossa on the planar image; single photon emission computed tomography-computed tomography (CT) demonstrated tracer pooling in the perirenal collection. In addition, the CT detected nontracer-avid parenchymal lung nodules and hypodense liver lesions consistent with metastatic disease. The perinephric urinary leak was drained by percutaneous drainage, confirmed by diuretic renography the following day., Competing Interests: There are no conflicts of interest.

Purpose: The aim of this study was to compare the diagnostic performance of F-fluorocholine (FCH) PET/CT and dynamic contrast-enhanced MRI (DCE-MRI) of pelvis in restaging prostate cancer (PC) patients with biochemical recurrence (BCR) following radical prostatectomy (RP)., Methods: Twenty PC patients who had undergone RP and had BCR were recruited in this study. All the patients underwent whole-body FCH PET/CT and DCE-MRI of the pelvis. An overall pattern of recurrent disease was analyzed, and diagnostic accuracy for the detection of pelvic disease recurrence by the 2 modalities was evaluated by taking histopathologic analysis as the criterion standard. The whole-body FCH PET/CT images were also analyzed separately for the presence of any extra lesion(s)., Results: The initial mean Gleason score was 6.3 ± 1.53 (range, 4-9). The mean prostate-specific antigen levels at the time of relapse were 1.9 ± 2.87 ng/mL (range, 0.24-13.2 ng/mL). MRI findings were positive for primary tumor recurrence in the prostate bed in 6 patients (6/20 [30.0%]), pelvic lymph node metastases in 4 patients (4/20 [20.0%]), and for pelvic skeletal metastases in 2 patients (2/20 [10.0%]), respectively. On the other hand, FCH PET/CT results were positive in the corresponding sites in 7 (7/20 [35.0%]), 9 (9/20 [45.0%]), and 2 patients (2/20 [10.0%]), respectively. F-fluorocholine PET/CT and MRI showed comparable results in terms of sensitivity, specificity, and positive and negative predictive values for PC characterization. The whole-body FCH PET/CT was found to be useful in identifying unknown distant metastases in a significant proportion of patients., Conclusions: The correlative whole-body FCH PET/CT and pelvic DCE-MRI offer a complementary and comprehensive diagnostic workup for better management of PC patients with BCR following RP.