Consistent and significant myocardial FDG uptake suppression is possible in most patients using LCHFPP diet. The LCHFPP diet, if taken as per protocol, leads to consistent myocardial FDG uptake suppression to allow for adequate evaluation of the left coronary artery inflammation in nearly all the patients. LCHFPP diet is also significantly more efficacious than prolonged (>12 hours) fasting protocol in suppressing myocardial FDG uptake.

Lymphoma is the seventh most common type of malignancy in both sexes. It is a neoplastic proliferation of lymphoid cells at various stages of differentiation and affects lymph nodes with infiltration into the bone marrow, spleen and thymus. However, extra nodal involvement is frequently seen in many cases. With the development of dedicated positron emission tomography (PET) scanners with fused computed tomographic (CT) systems in the same gantry, [18F]fluorodeoxyglucose (FDG)-PET/CT has become a major tool in the evaluation of lymphomas and it is inimitable in certain situations such as assessment of response to therapy. Extranodal lymphoma can present with diverse manifestations and sometimes mimics other organ-related pathologies. Knowledge of the protean manifestations of extranodal lymphoma is required to accurately detect the disease and differentiate it from the various physiologic and benign causes of FDG uptake in various organs. We present a case series of extranodal involvement of histologically proven cases of lymphomas detected on FDG-PET/CT at our institute to demonstrate the challenges in interpretation of extranodal lymphoma.

Introduction:Radionuclide bone scan (BS) used to be the investigation of choice for detecting osseous metastases in prostate cancer. Now, with the availability serum prostate specific antigen (PSA) testing, clinicians do have a timely, cost-effective method to determine those patients who are highly unlikely to have osseous metastases. We determine the utility of PSA for predicting the presence of skeletal metastasis on BSs in prostate cancer patients.Materials and Methods:Retrospective analysis of medical records of 322 consecutive prostate cancers patients subjected to BS during the last 3 years was done. 52 cases were excluded due to following reasons: Serum PSA not available, hormonal or other therapy given prior to serum PSA measurement, and/or BS, and symptomatic for bone metastasis. In remaining 270 cases, PSA value and BS were evaluated. BS was performed with Tc99m methylene diphosphonate (MDP) as per the standard protocol.Results:BS was found to be positive in 153/270 (56%) and negative in 117 (46%) patients. Of the 153 positive cases, 108 (70%) had serum PSA > 100 ng/ml, 42 (28%) had PSA of 20-100 ng/ml and only 3 (2%) had PSA < 20 ng/ml. All the patients with PSA > 100 ng/ml had multiple skeletal metastasis. Of the 117 negative cases, 110 (94%) had a PSA < 20 ng/ml, 5 had between 20 and 100 ng/ml and only 2 (1.8%) had PSA > 100 ng/ml. Of the 113 patients with serum PSA < 20 ng/ml, 110 (97.4%) did not show any bony metastasis. 150/157 (95.5%) patients with PSA > 20 ng/ml had bone metastasis. Using this criterion, 110 (40.7%) scans would have been omitted.Conclusions:Serum PSA < 20 ng/ml have high predictive value in ruling out skeletal metastasis. Our data are in corroboration with results from previous studies that BS should be performed only if PSA > 20 ng/ml. Using this cut-off, unnecessary investigation can be avoided. Avoiding BS in this group of patients would translate into a significant cost-saving and reduction in their psychological and physical burden.

Increase in radiopharmaceutical uptake is an indicator of progression of disease. Paradoxical increase in the radiopharmaceutical uptake also occurs during favorable response to therapy, which is designated as flare phenomenon. Flare phenomenon is well documented on bone scinitgraphy when initially noted lesions show increased radiotracer uptake after therapy is instituted. This happens despite favorable response to the treatment. The osteoblastic activity associated with healing response of bone tumors is the cause of flare phenomenon. Recently, metabolic flare phenomenon has been described in patients with breast cancer who undergo hormonal therapy. Changes in the hormonal level during initial part of the treatment is the cause of metabolic flare. We describe a patient with bilateral breast cancer who underwent second line chemotherapy along with bevacizumab. Serial positron emission tomography scans done showed interesting phenomenon of metabolic flare.

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