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Introduction: Radical prostatectomy (RP) and radical radiotherapy (RT) are well established primary curative options for localized prostate cancer. Despite technical improvements, prostate-specific antigen (PSA)-recurrence after RP and RT is a common clinical scenario. We aimed to assess the role of 68Gallium (68Ga) prostate-specific membrane antigen positron emission tomography computed tomography (PSMA PET/CT) in patients with biochemical recurrence of prostate cancer after RP or RT for the detection and localization recurrent and metastatic disease. Materials and Methods: We ambispectively (70 retrospective and 100 prospective) analyzed the data of men with biochemical recurrence post-RP and post-RT who were evaluated by 68Ga PSMA PET/CT at our institute. We aimed to assess the relationship between serum PSA levels and the probability of having a positive scan in patients with recurrent prostate cancer. Results: The study included 170 men, all had adenocarcinoma of the prostate, 124/170 had previous RP and 46/170 had prior RT. The median serum PSA in the RP group was 1.8 ng/ml and 5.2 ng/ml in the RT group. In the post-RP cohort, the detection rate of 68Ga PSMA PET/CT was 39.3% for PSA 0.2 to

Fibrodysplasia ossificans progressiva is a rare genetic disease believed to occur in approximately 1 in 2 million people worldwide and is characterized by progressive extraosseous ossification over the course of a lifetime in an inevitable and unpredictable episodic manner, with most patients being confined to a wheelchair by the third decade of life and requiring life-long care. The extraosseous calcification involves ligaments, tendons, muscles, and connective tissue leading to severe restriction of movements. Another hallmark of this condition is abnormal great toes. The diagnosis is often made on clinical and radiological examination, but Technetium-99m methylene diphosphonate (Tc-99m MDP) bone scan is usually indicated to determine the extent of the disease. We hereby present a case series comprising of four patients suffering from this debilitating illness who underwent Tc99m MDP bone scan for initial diagnosis and localizing sites of heterotopic ossification.

We report the case of a 43-year-old male patient, who presented with severe osteoporosis and pain at multiple sites and a chest X-ray suggestive of few cystic lesions in bilateral ribs. Subsequently, the patient was referred for bone scan, in view of the suspicion of polyostotic fibrous dysplasia or neoplastic lesions. Bone scan showed homogenously increased tracer uptake in the axial and appendicular skeletal system, suggestive of metabolic superscan. Computed tomography neck localized right inferior parathyroid adenoma and expansile lytic skeletal lesions suggestive of brown tumors were also seen. This case highlights the importance of bone scan, helping in the differential diagnosis of multiple skeletal lesions.

Sarcoidosis is a chronic granulomatous disorder of unknown etiology which primarily affects the respiratory system. However, 0.5%–2.5% of patients with sarcoidosis show muscle involvement, namely sarcoid myopathy. F-18 Fluorodeoxyglucose positron-emission tomography (F-18 FDG PET) has become an important component of the diagnostic algorithm of these patients, owing to its ability to assess disease extent and identify occult sites of disease involvement and guiding sites of biopsy. Awareness of pattern of FDG uptake in sarcoid myopathy not only helps in identifying muscular involvement in already known cases but also helps in the initial diagnosis of sarcoidosis as in the present case.

Hepatic veins and inferior vena cava are opacified during the delayed venous phase on triphasic contrast-enhanced computed tomography (CECT) abdomen scan. However, their early opacification/visualization in the arterial phase is usually due to retrograde flow of intravenous contrast from the right atrium in patients with right-sided heart failure or right ventricular dysfunction. Awareness and recognition of this phenomenon is important for nuclear medicine physicians reporting F18 fluorodeoxyglucose positron emission tomography–computed tomography (FDG PET CT) scan with diagnostic CECT.

Neuroendocrine tumours (NETs) are rare, heterogeneous group of tumours which usually originate from small, occult primary sites and are characterized by over-expression of somatostatin receptors (SSTRs). Positron emission tomography/computed tomography (PET/CT) using Ga-68-labeled-somatostatin-analogues have shown superiority over other modalities for imaging of NETs. The objective of the study was to retrospectively evaluate the efficacy of Ga-68 DOTANOC PET/CT imaging in detecting the primary site in patients with metastatic NETs of unknown origin and its impact on clinical decision making in such patients.Between December 2011 and September 2014, a total of 263 patients underwent Ga-68 DOTANOC PET/CT study in our department for various indications. Out of them, 68 patients (45 males, 23 females; mean age, 54.9±10.7 years; range, 31-78 years) with histopathologically proven metastatic NETs and unknown primary site (CUP-NET) on conventional imaging, who underwent Ga-68 DOTANOC PET/CT scan as part of their clinical work-up were included for analyses. Histopathology (wherever available) and/or follow-up imaging were taken as reference standard. Quantitative estimation of SSTR expression in the form of maximal standardized uptake value (SUVmax) of detected primary and metastatic sites was calculated. Follow-up data of individual patients was collected through careful survey of hospital medical records and telephonic interviews.Maximum patients presented to our department with hepatic metastasis (50 out of 68 patients) and grade I NETs (50%). Ga-68 DOTANOC PET/CT scan identified primary sites in 40 out of these 68 patients i.e., in approximately 59% patients. Identified primary sites were: small intestine [19], rectum [8], pancreas [7], stomach [4], lung [1] and one each in rare sites in kidney and prostate. In one patient, 2 primary sites were identified (one each in stomach and duodenum). Mean SUVmax of the detected primary sites was 25.1±18.0 (median: 16.25; range, 2.1-150). Significant positive correlation was found between SUVmax of detected primary site and SUVmax of the histopathologically proven sites of metastasis (r=0.662; P0.0001). Based on the findings of the Ga-68 DOTANOC PET/CT scan, 3 out of 40 patients underwent definitive treatment for their primary tumour (1 gastric, 1 ileal and 1 prostatic tumour). One patient was being planned for resection of primary rectal lesion at the time of data-collection. Thirty-six out of 68 patients were started on long-acting somatostatin analogues or chemotherapy or targeted therapy. Two patients underwent multiple cycles of peptide receptor radionuclide therapy (PRRNT) using (90)Y and (177)Lu labeled somatostatin analogues.Our findings indicate that Ga-68 DOTANOC PET/CT is a promising imaging modality in patients with metastatic NETs of unknown origin for detection of the primary site and in guiding their therapeutic management.

Context: F-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) scan and hypothyroidism. Aims: The aim was to determine whether the intensity of diffuse thyroid gland uptake on F-18 FDG PET/CT scans predicts the severity of hypothyroidism. Materials and Methods: A retrospective analysis of 3868 patients who underwent F-18 FDG PET/CT scans, between October 2012 and June 2013 in our institution for various oncological indications was done. Out of them, 106 (2.7%) patients (79 females, 27 males) presented with bilateral diffuse thyroid gland uptake as an incidental finding. These patients were investigated retrospectively and various parameters such as age, sex, primary cancer site, maximal standardized uptake value (SUVmax), results of thyroid function tests (TFTs) and fine-needle aspiration cytology results were noted. The SUVmax values were correlated with serum thyroid stimulating hormone (S. TSH) levels using Pearson's correlation analysis. Statistical Analysis Used: Pearson's correlation analysis. Results: Clinical information and TFT (serum FT3, FT4 and TSH levels) results were available for 31 of the 106 patients (27 females, 4 males; mean age 51.5 years). Twenty-six out of 31 patients (84%) were having abnormal TFTs with abnormal TSH levels in 24/31 patients (mean S. TSH: 22.35 μIU/ml, median: 7.37 μIU/ml, range: 0.074-211 μIU/ml). Among 7 patients with normal TSH levels, 2 patients demonstrated low FT3 and FT4 levels. No significant correlation was found between maximum standardized uptake value and TSH levels ( r = 0.115, P > 0.05). Conclusions: Incidentally detected diffuse thyroid gland uptake on F-18 FDG PET/CT scan was usually associated with hypothyroidism probably caused by autoimmune thyroiditis. Patients should be investigated promptly irrespective of the intensity of FDG uptake with TFTs to initiate replacement therapy and a USG examination to look for any suspicious nodules.

The association between cancer and venous thrombosis is well established. However, that between malignancy and arterial thrombosis is less well described. We herein report a 48-year-old male patient diagnosed with base of tongue carcinoma, referred for Tc-methylene diphosphonate (MDP) bone scan study to evaluate recently developed pain and numbness in his right leg while undergoing chemoradiation. Tc-MDP bone scan study revealed complete absence of radiotracer distribution in the right lower limb below the knee region. This finding was inferred to be due to avascularity in this region secondary to thrombo-embolism that was substantiated by color Doppler sonography.

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) has revealed many unusual presentations and early detection of metastasis in many carcinomas. Epidural involvement in the spine is mostly sequelae of direct infiltration from bony involvement. Direct hematogenous spread to epidural space is very rare. Early diagnosis and treatment before the development of permanent neurologic and functional deficits is essential for a favorable prognosis in such cases. We report here a case of solitary spinal epidural metastasis from lung cancer which was the only systemic metastasis detected on F-18 FDG PET/CT and later confirmed by clinical and regional magnetic resonance imaging findings. This report is, to the best of our knowledge, the first description of such a presentation of systemic metastasis from lung cancer on F-18 FDG PET/CT.