Background and Objective: People with amnestic mild cognitive impairment (aMCI) are at a higher risk of developing Alzheimers Dementia (AD) than their cognitively normal peers. Decreased glucose metabolism with F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is a downstream marker of neuronal injury and neurodegeneration. The risk of developing AD is higher in patients with aMCI who have a pattern of AD related glucose metabolic changes on FDG-PET than those who do not have these changes. We evaluated the utility of visual and 'statistical parametric mapping (SPM)-supported reading' of the FDG-PET scans of patients clinically classified as aMCI for identification of predementia patterns and for prediction of their progression to AD (PTAD). Patients and Methods: A total of 35 patients diagnosed as aMCI (mini mental state examination (MMSE) score ≥ 25) at the cognitive disorders and memory (CDM) clinic of speciality neurology centers were referred for a resting FDG-PET study. All patients had a detailed neurological, neuropsychological, and magnetic resonance imaging (MRI) evaluation prior to referral. Mean age of patients was 67.9 ± 8.7 (standard deviation (SD)) years, male: female (M: F) =26:9. Twenty healthy age-matched controls were included in the study for SPM (http://www.fil.ion.ucl.ac.uk/spm/">). Scans were interpreted visually and using SPM. Each scan was classified as high, intermediate, or low likelihood for PTAD. Results: On visual analysis, four scans were classified as high likelihood of PTAD and reveled hypometabolism in AD related territories. Seven patients had hypometabolism in at least one AD related territory and were classified as intermediate likelihood for PTAD. Two patients had hypometabolism in other than AD territories, while 22 patients did not show any significant hypometabolism on their FDG-PET scans and were classified as low likelihood for PTAD. SPM analysis of these cases confirmed the areas hypometabolism in all 13 patients compared to a normal subgroup (P < 0.05). On follow-up of 24 months, all four cases with high likelihood scans had progression of cognitive deficits and were confirmed as AD in the CDM clinic while none of the others showed cognitive decline. Interpretation and Conclusion: A pattern of AD hypometabolism on the FDG-PET study is useful for predicting PTAD. A longer follow-up of patients with hypometabolism in single AD territories is needed to predict their clinical behavior.

Purpose : To examine the frequency and significance of visualization of popliteal nodes during lymphoscintigraphy for the investigation of lower extremity swelling. Materials and Methods: Technetium-99m-labeled nanocolloid was injected subcutaneously in the first web spaces of both feet of 90 patients (24 males, 66 females; age range, 4-70 years) who had clinical evidence of lower limb lymphedema and were referred for routine lymphoscintigraphy; imaging was performed 5, and 90 minutes after injection without any vigorous exercise between the injection and imaging. Results: According to the scan findings, patients were divided into two groups; group I included 63 patients without popliteal nodes visualization on scanning, and group II included 27 patients with positive popliteal nodes uptake. None of patients with primary lymphedema (N = 22) due to agenesis or hypoplasia showed popliteal node uptake, whereas, patients with secondary lymphedema (N = 68) had either severe (N = 23) or partial (N = 45) lymphatic obstruction. A high positive association of popliteal node uptake with the severity of lymphatic obstruction was noted. Popliteal nodes were visualized in 26 of 57 patients with dermal back flow (46%), and in only 1 of 33 patients without dermal back flow (3%). There was a strong association between skin rerouting and popliteal node visualization (P < 0.01). Skin changes were detected in 24 patients (38%) with positive popliteal node uptake. Conclusion: Popliteal lymph nodes uptake during lymphoscintigraphy for clinical lymphedema of the lower limb indicates lymph rerouting through the deep system and raises a diagnosis of higher severity and longer duration of lymphatic dysfunction.

Purpose: Role of (18 [F] fluorine-18-labeled 2-fluoro-2-deoxy-D-glucose [FDG] positron emission tomography-computed tomography [PET-CT]) in the evaluation of axillary lymph node involvement in T1T2N0 breast cancer and compare results with sentinel lymph node biopsy (SLNB). Methods: A total of 37 patients of proven T1T2N0 breast cancer were included in the study. Patients with past history of breast surgery, T3T4 disease, uncontrolled diabetes mellitus and pregnant patients were excluded from the study. Pre-operative FDG PET-CT was performed followed by sentinel lymph node (SLN) biopsy with blue dye or combined technique. Results: SLN was identified in 32 of 37 patients with an identification rate of 86.48% (32/37). With combined technique SLN identification rate was 100% (6/6) while with blue dye alone; it was 83.8% (26/31). Among 37 patients, 16 had axillary metastases of which 12 had macrometastases and four had micrometastases detected by immunohistochemistry (IHC). Of 12 patients with axillary macrometastases, skip metastases were present in two patients in whom SLN was negative and in two patients SLN was not identified, but axillary dissection showed metastases. PET-CT had shown sensitivity, specificity, negative predictive value and positive predictive value of 56%, 90%, 73%, and 81.8%, respectively. IHC of SLN detected four patients with micrometastases upstaging the disease by 11% (4/37). Conclusion: Because FDG PET-CT has a high specificity in the evaluation of axillary lymph node involvement in T1T2N0 breast cancer patients according to the results of this study if FDG PET-CT is positive in axillary lymph nodes, axillary lymph node dissection may be considered instead of SLNB.

Background: There are numerous methods for calculation of glomerular filtration rate (GFR), which is a crucial measurement to identify patients with renal disease. Aims: The aim of this study is to compare four different methods of GFR calculation. Settings and Design: Clinical setup, prospective study. Materials and Methods: Data was collected from routine renal scans done for voluntary kidney donors (VKD) or renal transplant recipients 6 months after transplantation. Following technetium-99m diethylene triamine penta acetic acid injection, venous blood samples were collected from contralateral arm at 120, 180, and 240 min through an indwelling venous cannula and direct collection by syringe. A total volume of 1 ml of plasma from each sample and standards were counted in an automatic gamma counter for 1 min. Blood samples taken at 120 min and 240 min were used for double plasma sample method (DPSM) and a sample taken at 180 min for single plasma sample method (SPSM). Russell's formulae for SPSM and DPSM were used for GFR estimation. Gates' method GFR was calculated by vendor provided software. Correlation analysis was performed using Pearson's correlation test. Results: SPSM correlated well with DPSM. GFR value in healthy potential kidney donors has a significant role in the selection of donors. The mean GFR ± (standard deviation) in VKD using SPSM, DPSM, camera depth method and Cockroft Gault method was 134.6 (25.9), 137.5 (42.4), 98.6 (15.9), 83.5 (21.1) respectively. Gates' GFR calculation did not correlate well with plasma sampling method. Conclusions: Calculation of GFR plays a vital role in the management of renal patients, hence it was noted that Gates GFR may not be a reliable method of calculation. SPSM was more reliable. DPSM is reliable but cumbersome. It is difficult to accurately calculate GFR without a gold standard.

Introduction: Tc-99m macro aggregated albumin (MAA) is synonymous for lung perfusion scintigraphy and is part of the study in the evaluation of pulmonary thromboembolism. We wanted to highlight the utilities of Tc-99m MAA other than pulmonary embolism as a pictorial assay. Materials and Methods: Patients referred for Tc-99m MAA scintigraphy under various indications were included in this pictorial essay. Commercially available TechneScan LyoMAA cold kit from Mallinckrodt Medical B.V., Holland was used. Acquisition protocols for different indications are described in this article. Different clinical indications (e.g., pulmonary artery stenosis, hepatopulmonary syndrome, FEV1 calculation in lung surgery planning, selective internal radiation therapy planning, venography for deep venous thrombosis, left to right cardiac shunts, etc.) where Tc-99m MAA scintigraphy was asked for; how it helped in different clinical scenarios and how it can be used clinically is explained with unique and interesting case examples and images. We also reviewed the literature to look for certain remote indications of MAA imaging for the sake of completion like - (shunt scintigraphy, peritoneopleural communication, etc.) Conclusion: Tc-99m MAA is a very useful radiopharmaceutical, which can be used for many other indications apart from the commonly used indication of lung perfusion scan in pulmonary embolism. It can provide useful clinical information in other indications, which we try to highlight in this article.

The authors describe a 50 days old pre-term infant with persistent hyperinsulinemic hypoglycemia of infancy in whom Ga-68 DOTATATE positron emission tomography/computerized tomography scan showed diffusely increased tracer uptake in the entire pancreas with no abnormal tracer uptake anywhere else in the body, suggestive of a diffuse variant of nesidioblastosis.

A chronic kidney disease male patient presenting with bone pains, fever, weakness, and clinically ascites was subjected to four technetium-99m-methylene diphosphonate (Tc99m-MDP) bone scans, two before renal transplant and two after renal transplants. Pretransplant bone scan revealed metabolic bone disease with focal insufficiency fractures. Marked extraosseous activity in both lungs and stomach was also visualized. On regular hemodialysis (HD) after 4 months, repeat pretransplant bone scan showed persistent uptake in lungs and stomach, representing altered calcium metabolism with microcalcifications. He underwent human leukocyte antigen (HLA) matched live donor renal transplantation, started on immune-suppression and steroids. Posttransplant bone scan at 20 days revealed no definite interval change, but bone scan performed approximately 17 months posttransplant showed resolving metabolic bone disease and the tracer uptake in the lungs and stomach was no more visualized. Patient clinically followed-up until the date (February 2013) is asymptomatic with serum creatinine of 1.5 mg/dl, no bone scan done.

Malignant peripheral nerve sheath tumors (MPNSTs) are rare tumors, with an estimated incidence of 0.1/100,000/year. They are regarded as a rare variety of soft-tissue sarcomas that derive from peripheral nerves or from cells associated with the nerve sheath. Until 50% of observed MPNSTs occur in patients with neurofibromatosis 1 (NF1). The typical presenting signs and symptoms of a PNST are a palpable mass involving a peripheral nerve, loss of nerve function and/or pain. Recently, positron emission tomography (PET) has been used to detect 18F-fluorodeoxyglucose uptake in these tumors. Most of the PET studies have been reported in patients with NF1. We report a case of sporadic MPNST masquerading as infectious dermatoses, with an unusual PET/computed tomography presentation.

We report a case of a patient with hepatocellular carcinoma (HCC) who presented with back pain related to bone metastasis. HCC metastasizes by hematogenous and lymphatic routes commonly to the lungs, regional lymph nodes, kidney, bone marrow and adrenals. In this extremely rare case, the patient had no known liver disease, but presented with liver lesions and multiple bone lesions involving vertebrae, ribs, pelvic bones and left femur with associated expansile soft-tissue components. These bone lesions were first detected from a positron emission tomography scan. Pathological examination of biopsy material taken from the left eighth rib confirmed metastatic HCC. In conclusion, if a patient has expansile osteolytic bone lesions, bone metastasis from HCC should be included in the differential diagnosis.

Tumor induced osteomalacia (TIO) or oncogenic osteomalacia is a rare condition associated with small tumor that secretes one of the phosphaturic hormones, i.e., fibroblast growth factor 23, resulting in abnormal phosphate metabolism. Patients may present with non-specific symptoms leading to delay in the diagnosis. Extensive skeletal involvement is frequently seen due to delay in the diagnosis and treatment. The small sized tumor and unexpected location make the identification of tumor difficult even after diagnosis of osteogenic osteomalacia. The bone scan done for the skeletal involvement may show the presence of metabolic features and the scan findings are a sensitive indicator of metabolic bone disorders. We present the bone scan findings in three patients diagnosed to have TIO.

Sinister undesirable pathologies often accompany malignancies. Though the entire emphasis is on cancer management, these benign conditions are more life-threatening than the primary malignancy itself. We report an interesting imaging finding of broncho-esophageal fistula leading to lung abscess on ¹⁸ F- fluoro-deoxy-glucose positron emission tomography/computed tomography (FDG PET/CT) in large middle esophageal cancer, which due to early detection, was promptly managed.

Lytic bone metastases are rare in prostate cancer. We here present 18 fluorine fluorodeoxyglucose ( ¹⁸ F-FDG) positron emission tomography computed tomography (PET-CT) images of a 67-year-old male patient with lytic metastases from prostate cancer. Repeat ¹⁸ F-FDG PET-CT done 6 months later showed response to medical castration therapy. While the role of ¹⁸ F-FDG PET-CT for sclerotic bone metastases in prostate cancer remains controversial, it appears to be useful for detection and response assessment of lytic prostate cancer metastases.

A primitive neuroectodermal tumor (PNET) of the thoraco-abdominal region is one of a group of small round cell tumors usually found in children and young adults, originally described by Askin et al. Most cases arise in the soft-tissues of the thorax, but may rarely occur within the lung with the symptoms of chest wall pain, pleural effusion and dyspnea. The authors present two cases demonstrating the utility of F18 fluorodeoxyglucose positron-emission tomography/computed tomography in the staging and prognosis of PNET of the chest wall.

Reconstruction artifacts often affect the image quality. An unusual wavy imaging pattern was seen on computed tomography (CT) part of positron emission tomography/CT, on sagittal and coronal images. This pattern was corrected on realignment of CT tube. This artifact, popularly known as stair step artifact, is rarely cited in the literature and our case generates a practical scenario of how it affects the image quality and how it is corrected.

Extrameduallary plasmacytoma of ovary is extremely rare. We report a case of involvement of ovary in a treated case of plasmacytoma of 2 ^nd part of duodenum, which was initially thought to be physiological luteal activity. However, follow up whole body FDG PET-CT scan shows appearance of metabolically active soft tissue mass in left adnexal region which confirmed to be extra-medullary plasmacytoma of ovary on histopathology.