68Ga-PSMA-11 uptake in tracheal mucus plug - a potential pitfall.

Prostate-specific membrane antigen (PSMA) PET/CT is a well-acclaimed imaging modality for prostate cancer (PCa). However, many reports have highlighted PSMA radioligand uptake in a variety of benign tumors and lesions. We report a case of PCa in which 68 Ga-PSMA-11 uptake was noted in the tracheal lumen. However, 18F-PSMA-1007 PET/CT was done on a subsequent day, which demonstrated no abnormal radiotracer uptake or morphological lesion within the tracheal lumen. This case highlights an uncommon finding of PSMA ligand uptake in a tracheal mucus plug (non-prostatic benign uptake), which may be misinterpreted as a false-positive finding.

Radioiodine Therapy in Patient with Differentiated Thyroid Cancer and End-Stage Renal Disease on Maintenance Hemodialysis: Case Report with Review of Literature.

Surgical resection followed by radioactive iodine (131I) therapy constitutes a standard treatment for differentiated thyroid cancer. 131I is normally excreted through the kidneys, and treatment of patients with end-stage renal disease on hemodialysis requires special attention to the dose of 131I, the timing of dialysis, and radiation safety. We present a case of end-stage renal disease in a postthyroidectomy patient on hemodialysis who required radioactive iodine ablation, and we review the literature.

Hematological Markers as Predictors of Treatment Outcomes with Lutetium 177 (177Lu)-DOTATATE in Patients with Advanced Neuroendocrine Tumors.

Background: Chronic inflammation has been linked to the development and prognosis of neuroendocrine tumors (NETs). The current study intended to evaluate the role of peripheral hematological inflammatory markers, viz. the platelet-lymphocyte ratio (PLR), neutrophil-lymphocyte ratio, and monocyte-lymphocyte ratio, as predictors of treatment outcomes in patients with advanced NETs after Lutetium-177(177Lu)-DOTATATE therapy. Materials and Methods: Data of consecutive patients with advanced metastatic and/or inoperable NETs treated with 177Lu-DOTATATE from the year 2012 to 2019 at the authors' center were retrospectively analyzed. Results: Forty-two NET patients (median age: 49.5 years) received a median cumulative activity of 29.6 GBq of 177Lu-DOTATATE over 2-5 cycles at 8-12-week intervals. The median progression-free survival (PFS) of the study cohort was 30 months (95% confidence interval, CI: 18.2-41.9 months). A baseline PLR ≥173.1 was found to be a significant predictor of poor PFS with a univariate hazard ratio of 3.82 (95% CI: 1.21-12.03); however, the association was not significant on multivariate analysis. The median overall survival was not reached and none of the parameters were significantly associated with it. Conclusions: A higher baseline PLR was shown to be associated with a negative outcome on PFS after 177Lu-DOTATATE therapy and is a promising marker for future larger studies.

177Lu-DOTATATE Plus Radiosensitizing Capecitabine Versus Octreotide Long-Acting Release as First-Line Systemic Therapy in Advanced Grade 1 or 2 Gastroenteropancreatic Neuroendocrine Tumors: A Single-Institution Experience.

PURPOSE: To compare the efficacy and safety of 177Lu-DOTATATE plus radiosensitizing capecitabine and octreotide long-acting release (LAR) as first-line systemic therapy in advanced well-differentiated gastroenteropancreatic neuroendocrine tumors (GEP-NETs). MATERIALS AND METHODS: Data of consecutive patients of advanced inoperable or metastatic grade 1 or 2 GEP-NETs treated with first-line 177Lu-DOTATATE plus radiosensitizing capecitabine or octreotide LAR from September 2012 to December 2019 were collected and analyzed for response, toxicity, and survival outcomes. RESULTS: Seventy-six patients (median age: 53 years; range 14-81 years) with treatment-naïve advanced grade 1 or 2 GEP-NETs were included. Thirty-six patients received a median cumulative dose of 27.3 GBq of 177Lu-DOTATATE intravenously at 8-12 weeks' intervals along with 1,250 mg/m2 oral capecitabine on days 0-14 of each cycle of 177Lu-DOTATATE, whereas 40 patients were administered 30 mg octreotide LAR intramuscularly every 4 weeks. Using response evaluation criteria in solid tumor 1.1, the objective response rate was 38% in the 177Lu-DOTATATE arm compared with 15% in the octreotide LAR arm (P = .025), whereas the disease control rates were 88% and 67% in 177Lu-DOTATATE and octreotide LAR arms, respectively (P = .035). The median durations of progression-free survival in the 177Lu-DOTATATE and octreotide LAR arms were 54 months and 16 months, respectively (P = .017), whereas the median overall survival was not reached and not significantly different across both the arms. Of the treatment-related adverse events, no major difference was observed in the occurrence of grade 3 or 4 toxicities between the two treatment arms. CONCLUSION: First-line systemic 177Lu-DOTATATE plus radiosensitizing capecitabine achieved better radiologic response and longer progression-free survival compared with octreotide LAR in patients with advanced grade 1 or 2 GEP-NETs. Future randomized controlled trials are, however, required to determine the best treatment sequence for the treatment-naïve patients with advanced GEP-NETs.

Comparative Performance of 99mTc-TRODAT-1 SPECT/CT and 18F-FDOPA PET/CT Imaging in Patients With Parkinson's Disease, Parkinson-Plus Syndrome, and Essential Tremor.

PURPOSE: The aim of this study was to assess the utility of presynaptic dopaminergic imaging using 99mTc-TRODAT-1 SPECT/CT and 18F-FDOPA PET/CT and compare their performance in Parkinson's disease (PD), Parkinson-plus syndrome (PPS), and essential tremor (ET). PATIENTS AND METHODS: A total of 103 patients (PD = 48, PPS = 19, and ET = 36) were enrolled prospectively. Hoehn and Yahr (H&Y) staging and MDS-UPDRS (Movement Disorder Society-Sponsored Revision of Unified Parkinson's Disease Rating Scale) were done for PD and PPS cases. All the patients underwent 99mTc-TRODAT-1 SPECT/CT and 18F-FDOPA PET/CT brain scan. The scans were analyzed visually and semiquantitatively. Average pixel count and SUVmean of the striatum were calculated in SPECT and PET images, respectively, to calculate the specific uptake ratio of striatum (SUR). Comparison of scan findings and SURs among different groups and correlation with clinical characteristics was done. RESULTS: Symmetrical comma-shaped uptake was seen in bilateral striatum in ET cases with mean SURs significantly higher than in cases of early PD (H&Y stage I and II, n = 37), PD and PPS both on SPECT and PET images (P ≤ 0.001). The mean SURs between PD and PPS showed no significant difference (SPECT, P = 0.17; PET, P = 0.61). Substantial agreement (weighted κ = 0.659) was found between 99mTc-TRODAT-1 and 18F-FDOPA for the detection of presynaptic dopaminergic dysfunction. Specific uptake ratio of striatum correlation between SPECT and PET was statistically significant (r = 0.67; P < 0.01). A negative but nonsignificant correlation was found between the SURs and H&Y staging/MDS-UPDRS. CONCLUSIONS: Both 99mTc-TRODAT-1 SPECT/CT and 18F-FDOPA PET/CT showed substantial agreement and proved to be potential imaging biomarker for the detection of dopaminergic dysfunction, thus assisting in differentiating early PD/PD and PPS from ET cases.

Demonstration of focal physiologic in-vivo somatostatin receptor expression in the caput epididymis of the testes on 68Ga-DOTANOC PET/CT and 177Lu-DOTATATE post-therapy whole body scintigraphy.

  We present the case of a 60-year-old man with metastatic neuroendocrine tumor of the ileum following ileal resection, being evaluated for 177Lu-based peptide receptor radionuclide therapy. 68Ga-DOTANOC PET/CT showed focal increased tracer uptake in the scrotal region without any morphologic changes on the corresponding CT images. Similar increased tracer uptake was seen on post-therapy whole-body imaging following 177Lu-DOTATATE therapy. An USG guided FNA revealed no malignant cells on cytopathologic examination. This case illustrates that focal testicular tracer uptake, may not always be pathological and can represent a normal physiologic variant, similar to the diffuse testicular somatostatin receptor expression as previously reported in literature.

Peptide Receptor Radionuclide Therapy as First-Line Systemic Treatment in Advanced Inoperable/Metastatic Neuroendocrine Tumors.

PURPOSE: Advanced inoperable/metastatic neuroendocrine tumors (NETs) pose a therapeutic challenge with limited treatment options. Peptide receptor radionuclide therapy (PRRT), being specific in targeting the somatostatin receptors, is a promising and viable option in this setting. In this study, we intended to evaluate the role of PRRT as the first-line systemic therapy in advanced inoperable/metastatic NETs. METHODS: Data of consecutive patients of advanced inoperable/metastatic NETs treated with first-line Lu-DOTATATE at our center, from September 2012 to August 2019, were collected and analyzed. RESULTS: Forty-five patients (median age, 50 years; range, 14-72 years) with treatment-naive advanced NETs received a median cumulative dose of 27 GBq (range, 13.3-41.3 GBq; over 2-7 cycles) Lu-DOTATATE and 1250 mg/m capecitabine from days 0 to 14 of each PRRT cycle. Three patients were lost to follow-up, 2 had nonmeasurable lesions on CT, and hence, radiological response using Response Evaluation Criteria in Solid Tumors version 1.1 could be assessed in 40 patients. Twelve of 40 patients (30%) showed a partial response, whereas stable disease was observed in 22 of 40 patients (55%). Disease progression was limited to 6 of 40 patients (15%). Treatment-related adverse effects were minimal with grade 3/4 anemia, leukopenia, neutropenia, and hepatotoxicity observed in 2%, 2%, 4%, and 4% of the patients, respectively. Median progression-free survival was 48 months (95% confidence interval, 34.7-61.3 months). CONCLUSIONS: Our results indicate the efficacy and safety of first-line PRRT in advanced NETs. Future randomized trials, comparing PRRT and somatostatin analogs in treatment-naive patients, are required to identify the definite sequence of treatment options for these patients.

Pulmonary Recurrence of Lymphomatoid Granulomatosis Diagnosed on F-18 FDG PET/CT.

Lymphomatoid granulomatosis (LYG) is a rare, extranodal B-cell lymphoproliferative disorder. The disease commonly presents with nonspecific symptoms and imaging features, making the diagnosis and therapeutic response assessment difficult. While histopathology is the mainstay of diagnosis, different imaging modalities such as computed tomography (CT), magnetic resonance imaging, or F18-fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) can help in identifying the different organs involved. We present a case of LYG, post chemotherapy in remission for the past 5 years, presenting with symptoms of disease recurrence.

Incidental Detection of Hypothyroidism on 68Ga-PSMA-HBED-CC PET/CT Imaging.

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.

18F-FDG PET/CT in Tuberculosis: Can Interim PET/CT Predict the Clinical Outcome of the Patients?

PURPOSE OF THE REPORT: Tuberculosis (TB) is a major health problem. Activated macrophages in TB lesions show high metabolic activity and can be assessed using F-FDG PET/CT. This retroprospective study was done to evaluate the utility of F-FDG PET/CT in initial assessment and therapeutic response in patients with TB. MATERIALS AND METHODS: Eighty-seven patients (male-to-female ratio, 46:41) diagnosed with pulmonary TB and extrapulmonary TB underwent whole-body F-FDG PET/CT for initial assessment and a follow-up scan 3 to 4 months after initiation of antitubercular therapy (ATT). Visual and semiquantitative (SUVmax) analyses were used for scan assessment. Treatment responses on interim scans were categorized as complete metabolic response (CMR), favorable response to therapy (FRT), stable disease (SD), and disease progression (DP). CMR, FRT, and SD cases were considered as responders and DP cases as nonresponders. Treatment response was correlated with clinical outcome (mortality) and ATT duration. RESULTS: Baseline F-FDG PET/CT scans were positive in all the patients and detected additional disease sites than suspected clinically in 72% patients. On interim PET/CT, 13 patients showed CMR, 43 showed FRT, 8 showed SD, and 23 showed DP. A longer duration of ATT was seen in nonresponders (P ≤ 0.001) than responders. During follow-up, 9/87 patients died, out of which 8 patients were of DP group and 1 patient belonged to SD. Nonresponders showed 35% mortality compared with 1.6% in the responder group (P ≤ 0.001). CONCLUSIONS: F-FDG PET/CT is a valuable imaging modality for disease mapping and assessing therapeutic response. Treatment response in the interim PET/CT done at 3 to 4 months predicted the duration of ATT and clinical outcome of the patients.

An Unusual Presentation of Richter's Transformation of Chronic Lymphocytic Leukemia in Liver and Lung on 18F-Labeled Fluoro-2-Deoxyglucose Positron Emission Tomography/Computed Tomography.

Richter's transformation (RT) is a rare complication of chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) with unfavorable prognosis. The clinical and laboratory findings of RT are nonspecific and requires histopathological confirmation for the diagnosis. 18F-labeled fluoro-2-deoxyglucose positron-emission tomography/computed tomography (18F-FDG PET/CT) has shown higher diagnostic values for the detection of transformation of CLL/SLL to aggressive lymphoma. We present a case of CLL in remission for 6 years presenting with clinical features suggestive of RT. 18F-FDG PET/CT done in our case showed liver and lung involvement with no lymphadenopathy, which is an unusual presentation of RT.

68Ga-PSMA-HBED-CC PET/CT and 18F-FDG PET/CT in Ewing Sarcoma.

We present a case of a 19-year-old woman with Ewing sarcoma of the iliac bone in whom Ga-PSMA-HBED-CC PET/CT showed high radiotracer activity in the primary tumor. The present case documents the in vivo expression of PSMA in Ewing sarcoma family of tumors and adds on to the list of nonprostatic malignancies showing PSMA expression.

Fluorodeoxyglucose positron emission tomography/computed tomography in the diagnosis, assessment of disease activity and therapeutic response in relapsing polychondritis.

OBJECTIVE: To evaluate 18F-fluorodeoxyglucose (FDG) PET/CT in the assessment of disease activity, extent of the disease and response to therapy in relapsing polychondritis. METHODS: Twenty-five patients (9 men, 16 women) with a mean age of 38.2 years (s.d. 13.7; range 18-62), diagnosed to have relapsing polychondritis according to Damiani and Levine's modification of McAdam's criteria, who underwent PET/CT examination were included. Ten patients underwent a second PET/CT examination after therapy or during follow-up. Clinical symptoms and auxiliary examination findings were recorded. PET/CT findings were reviewed and correlated with the clinical symptoms. RESULTS: The major symptoms were aural pain (n = 21), nasal pain (n = 10), stridor (n = 5), cough (n = 9), fever (n = 8) and laryngeal tenderness (n = 8). The initial PET/CT was positive in 23/25 patients. PET/CT revealed involvement of auricular (n = 14), nasal (n = 8), laryngeal (n = 7), tracheobronchial (n = 6) and Eustachian (n = 3) cartilages with a mean maximum standardized uptake value (SUVmax) of 4.1 (s.d. 2.5; range 1.7-12.7). Fair correlation of aural/nasal pain/stridor with FDG avidity of cartilage involvement on PET/CT was noted. The key finding was detection of asymptomatic large airway involvement in seven patients (28%). Re-examination PET in 10 patients revealed complete therapeutic response (n = 5), partial response (n = 1), stable disease (n = 1), progressive disease (n = 1) and disease recurrence (n = 2). CONCLUSION: FDG PET/CT is a useful tool for the assessment of the disease activity and extent. It identified activity in clinically inaccessible sites that are of clinical significance. It is also useful in assessing treatment response and finding relapse.

18FDG-PET is sensitive tool for detection of extracranial tuberculous foci in central nervous system tuberculosis - Preliminary observations from a tertiary care center in northern India.

PURPOSE: To study the role of 18FDG- PET (Flourodeoxyglucose positron emission tomography) in a) determining the extent of cranial and extra-cranial disease and b) diagnosis as well as prognosis of CNS TB (central nervous system tuberculosis) including TBM (tuberculous meningitis). PATIENTS AND METHODS: This prospective observational study (n = 70) was carried out at a tertiary care institute in Northern India from 1.1.2017 to 30.6.2018. Diagnosis of TBM was made according to modified Ahuja's criteria. All patients were evaluated in detail and treated as per standard guidelines. All patients underwent 18FDG-PET scanning of brain and whole body at baseline. RESULTS: Mean age was 35.2 ±â€¯14.8 years. There were 37 men. Majority of patients (n = 47; 67.1%) were below 40 years of age. 43 (61.4%) patients were in stage II TBM. The mean duration of illness was 77 ±â€¯101.9 days. Majority of patients presented with fever (94.3%), headache (90%) and vomiting (84.3%). MRI was abnormal at baseline in 67 (95.7%) of patients, most common abnormalities being meningeal enhancement (68.6%) and tuberculomas (57.1%). PET was abnormal in 66 (95.7%) of patients. All these patients had either lung lesions (n = 62, 88.6%) or lymphadenopathy (n = 61; 87.1%). 18FDG-PET revealed evidence of brain lesions in 52 (74.3%) patients. It revealed vertebral involvement in 19 (27.1%) and genitourinary lesions in 9 (12.9%) patients. PET evidence of lymphadenopathy correlated significantly (p = .04) with good outcome in CNS TB. Conclusion 18FDG-PET does seem to have a promising role in initial evaluation of patients with CNS TB.

18F-FDG PET/CT in Graft Versus Host Disease-Associated Polymyositis.

Graft versus host disease (GVHD) is the most frequent and serious complication of allogenic hematopoietic stem cell transplant. Polymyositis is a rare neuromuscular manifestation of GVHD, which often responds well to corticosteroid and immunosuppression therapy. We present a case of a 38-year-old man with a known case of mixed-phenotype acute leukemia after hematopoietic stem cell transplant presenting with GVHD-associated polymyositis. F-FDG PET/CT done in this case not only helped in the detection of the muscle involvement but also helped in obtaining precise muscle sample for histopathological diagnosis using PET-guided biopsy.

68Ga-DOTA-Exendin PET-MRI Fusion Imaging in a Case of Insulinoma.

Persistent hyperinsulinemic hypoglycemia in adults is most commonly caused by insulinomas, which pose a diagnostic challenge to physicians, surgeons, and radiologists and require multimodality imaging for precise localization and staging. PET tracers such as F-FDOPA and glucagon-like peptide 1 receptor analogs have been used for imaging insulinomas. Glucagon-like peptide 1 receptor analogs have recently shown promising results in preoperative localization of these tumors, as all insulinomas express glucagon-like peptide 1 receptors. Ga-DOTA-Exendin PET and MRI done in the present case helped in precise localization and management of the culprit lesion, whereas contrast-enhanced CT and F-FDOPA PET failed to do so.

68Ga CXCR-4 PET/CT Imaging in an Atypical Case of Extramedullary Plasmacytoma Mimicking as Renal Cell Carcinoma.

Multiple-myeloma (MM) is a malignant plasma cell proliferation disorder and the second most common blood malignancy after non-Hodgkin lymphoma. The chemokine (CXCR-4) receptor analogues are the newer agents being postulated for myeloma imaging and have shown good diagnostic performance. We report a case of plasmacytoma with suspicious renal cell carcinoma, in whom Ga CXCR-4 PET/CT revealed tracer-avid lesion in the left perinephric region. PET/CT-guided biopsy from the tracer-avid lesion revealed plasmacytoma. PET/CT-imaging and guided biopsy using Ga CXCR4 receptor ligand, proved its usefulness for accurate localization of the culprit lesion and helped in definitive management of the patient.

Adenoid Cystic Carcinoma of Buccal Mucosa: Role of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Detection and Biopsy of Pulmonary Metastases and Assessment of Treatment Response.

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, 18F-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.

18F-FDG-Labeled Autologous Leukocyte PET-CT in a Patient With Aortic Valve-Tube Graft Infection After Bentall Procedure.

Infection of aortic valve-tube graft, although rare, is associated with high morbidity and mortality. Early identification of site and extent of infection is not only challenging but also crucial for adequate patient management and prognostication of disease. Combined clinical, laboratory investigation and imaging modalities assist in the identification of aortic valve graft infection. Molecular imaging techniques like PET/CT using F-FDG and F-FDG-labeled autologous leukocytes (LALs) have improved the sensitivity for detection of infection, resulting in better outcome for these patients. F-FDG-labeled autologous leukocyte PET/CT in our patient after Bentall procedure accurately localized the site and extent of infection.