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Extracranial metastasis from high-grade glial tumors is an extremely rare condition with its reported incidence being <1%. The most common sites reported in the literature are leptomeninges and spinal cord, followed by the liver, lung, and skeletal system. Its low incidence is thought to be related to the intrinsic aggressive biology of the tumor, thus reducing median overall survival in patients. As there is lack of knowledge about the mechanism of extracranial spread of glioma cells, its diagnosis and management remain a major challenge. We report two cases of extracranial metastases from glial tumors to cervical nodes and postoperative site involving preauricular region detected on F18 Fluoro ethyl tyrosine (FET) positron emission tomography-computed tomography and later on confirmed with histopathology Fluoro ethyl tyrosine. [ABSTRACT FROM AUTHOR]

Primary central nervous system lymphoma (PCNSL) is a rare, aggressive variant of extranodal non-Hodgkin's lymphoma. Although gadolinium-enhanced magnetic resonance imaging remains the initial imaging modality of choice, a whole-body F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography is imperative to exclude systemic lymphomatous involvement. Furthermore, the metabolic parameter, maximum standardized uptake value (SUVmax) of the lesion, tumor-to-normal cerebral tissue SUVmax ratio, and FDG uptake patterns help in differentiating intracranial lymphomas from High-grade Glioblastoma Multiforme (HGM) and infectious lesions, and hence, consolidating the diagnosis. In this pictorial essay, we present a series of PCNSL cases, representing the different imaging characteristics and metabolic uptake patterns. [ABSTRACT FROM AUTHOR]

Purpose: The blur introduced by breathing motion degrades the diagnostic accuracy of whole-body F-18 fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) in lesions adjacent to the diaphragm by increasing the apparent size and by decreasing their metabolic activity. This study aims to evaluate the efficacy of motion correction by four-dimensional phase-based respiratory-gated (RG) 18F-FDG PET-CT in improving metabolic parameters of lesions adjacent to the diaphragm (especially in the lungs or liver). Materials and Methods: Eighteen patients with known lung or liver lesions underwent conventional 18F-FDG PET-CT and respiratory-gated PET-CT acquisition of the desired region using a pressure-sensing, phase-based respiratory-gating system. Maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were obtained for these lesions from gated and nongated PET-CT images for analysis. Furthermore, a visual analysis of lesions was done. Statistics: Statistical significance of the RG image parameters was assessed by the two-tailed paired Student's t test and confirmed with the robust nonparametric Wilcoxon's signed-rank test (two-tailed asymptotic). Results: There was an overall significant increase in SUVmax (P 0.001) in all gating methods with a percentage increase maximum of about 18.13%. On gating methods, MTV decreased significantly (P = 0.001) than that of nongating method (maximum reduction of about 32.9%). There was a significant difference (P = 0.02) in TLG between gated and nongated methods. Conclusion: Motion correction with phase-based respiratory gating improves the diagnostic value of 18F-FDG PET-CT imaging for lung and liver lesions by more accurate delineation of the lesion volume and quantitation of SUV and can thus impact staging, diagnosis as well as management in selected patients. [ABSTRACT FROM AUTHOR]

Background: Positron emission tomography with computed tomography (PET-CT) using fluorine 18-fluorodeoxyglucose (F-18 FDG) is increasingly used to stage patients with locally advanced breast cancer and for assessing treatment response after neoadjuvant chemotherapy (NACT). Aims and Objectives: The aim of the study was to assess the correlation between PET-CT parameters and pathologic response of breast primary after NACT in breast cancer patients and to devise a grading system called NIMS grading system for response assessment using PET quantitative parameters. Materials and Methods: 55 patients who underwent F-18 FDG PET-CT before starting the therapy and again after completion of therapy were identified and included in the study. The clinical data and the histopathologic findings were recorded. All the patients received chemotherapy followed by surgery with axillary lymph node dissection. The PET-CT results were interpreted both qualitatively by visual analysis and quantitatively by estimating maximum Standardized uptake values(SUVmax) and other parameters – SUVmean, SUL, SUVBSA, Metabolic tumor volume (MTV) and Total lesion glycolysis (TLG). Results: The sensitivity and specificity of F-18 FDG PET-CT to detect the residual disease after neoadjuvant chemotherapy was 75.6% & 92.8% respectively. Differences between complete response and residual disease were significant for ΔSUVmax(p=0.005), ΔSUVmean(p=0.006), ΔSUL (0.005) and ΔSUVBSA(0.004), while ΔMTV and ΔTLG were not significantly different between the two groups. The new NIMS grading system included scoring of ΔSUVmax, ΔSUVBSA, ΔTLG and ΔMTV on scale of 1 to 4 and correlated well with PERCIST criteria. Conclusion: F-18 FDG PET-CT had a good accuracy in the detection of residual disease after completion of NACT. Pre chemotherapy PET-CT is not adequate to predict the response of primary tumour to chemotherapy. However, changes in the values of various PET-CT parameters are a sensitive tool to assess the response to chemotherapy. The new grading system is easy to use and showed good correlation to PERCIST. [ABSTRACT FROM AUTHOR]

Prostate cancer is the most common solid organ tumor in men and has been reported to metastasize to unusual sites such as the epididymis. The clinical standard for detecting recurrent disease is through positive emission tomography/computed tomography with the radiotracer 18F-DCFPyL binding prostate‑specific membrane antigen (PSMA) expressed by cancerous cells. Although PSMA can also be expressed physiologically, metastases are more likely to be intensely PSMA expressing and in a typical distribution depending on the extent of disease burden in the individual patient. A MEDLINE search revealed only three other case reports of isolated epididymal metastases from prostate cancer diagnosed with prostate‑specific membrane antigen positron emission tomography–computed tomography. This case series comprising both metastatic and physiological PSMA expression in the epididymis provides a useful framework for the interpreting physician when the possibility of this rare but important finding is encountered in prostate cancer imaging. [ABSTRACT FROM AUTHOR]

Small cell carcinoma (SCC) of the kidney is included in extrapulmonary SCC which is a group of extremely rare but highly aggressive cancers. There have been only a few case reports and small retrospective series in the literature describing the malignancy in kidneys. Most of the published reports describe the entity as a variant mixed with other tumor subtypes such as urothelial carcinoma, adenocarcinoma, and squamous cell carcinoma. Pure-form SCC in kidneys is exceedingly rare. Fluorodeoxyglucose positron emission tomography–computed tomography plays an essential role in the accurate staging evaluation of this cancer. [ABSTRACT FROM AUTHOR]

Background: Lymphoma is a common malignant proliferative disease in which bone marrow infiltration will upstage the disease and thus affect prognosis of the disease. As of now bone marrow biopsy is considered as a reference standard to find out bone marrow involvement in lymphoma. Performing an invasive and painful intervention in all newly diagnosed lymphoma patients is controversial. PET-CT is a non-invasive technique that gives functional information about the cells using the glucose metabolism. It can detect early bone marrow and extra medullary organ involvement which can lead to restaging of the disease. These advantages make PET-CT a valuable adjunct in diagnosis of lymphoma. Aims and Objectives: Our study aims to evaluate the usefulness of 18 F-FDG PET-CT, a non-invasive, semi quantitative whole body imaging technique for detection of early bone marrow and extra medullary organ involvement in lymphoma patients which in turn can obviate the need for bone marrow study (BMS). The primary objective of study is to categorise FDG uptake in bone marrow as diffuse /unifocal /multifocal / no uptake and to correlate pattern of FDG uptake to bone marrow study. Our study also assesses the role of FDG PET/CT in staging of lymphoma. Materials and Methods: Thirty patients with newly diagnosed lymphoma in the age group 18 to 75 years of both sexes within 3 months of diagnosis and who have not been started on any treatment was included in the study. Marrow uptake on FDG PET/CT has been categorized as diffuse, unifocal, multifocal and no uptake. Agreement between bone marrow study and FDG PET/CT has been assessed by reliability analysis using Cohen’s kappa. Sensitivity, specificity, PPV, NPV of PET/CT in detecting marrow involvement have been calculated. Results: The sensitivity, specificity, PPV, NPV and accuracy of 18 F-FDG PET-CT in detecting marrow involvement of lymphoma cases are 86.6%, 77.7%, 68.4%, 91.3% and 80.9% respectively. 18 F-FDG PET-CT detected bone marrow involvement in 86.6% (13 out of 15 total positive cases) cases of lymphoma which included both HL and NHL. Reliability analysis using Cohen’s kappa is used to test the agreement between bone marrow study and 18F-FDG PET/CT. k value of 0.6 was obtained which showed a moderate agreement between bone marrow study and 18F-FDG PET/CT in marrow assessment. Conclusion: 18F‐FDG PET/CT is a highly sensitive imaging modality which can pick up extra‐nodal organ and BMI in patients with lymphoma and can upstage the disease and alter treatment strategies. PET‐CT cannot completely replace the bone marrow study. However, being an invasive painful procedure, BMB can be avoided in cases with unifocal or multifocal marrow involvement on PET‐CT. [ABSTRACT FROM AUTHOR]

Large vessel vasculitis is a known but rare side effect of granulocyte colony-stimulating factor (G-CSF) therapy. We report a case of adenocarcinoma lung with pleural infiltration and mediastinal lymphadenopathy, who was treated with neoadjuvant chemotherapy and pegylated G-CSF. After three cycles, he developed a fever. He underwent F-18 fludeoxyglucose (FDG) positron emission tomography computed tomography for fever of unkwnown origin evaluation, which revealed a response to chemotherapy along with the appearance of FDG avid mural thickening in a few large arteries, suggesting a diagnosis of G-CSF-induced large vessel vasculitis. [ABSTRACT FROM AUTHOR]

The metastatic lesions to pancreas are reported in various malignancies. However, pancreatic metastasis from breast cancer is rare and difficult to diagnose due to nonspecific symptoms and imaging findings. At the time of diagnosis, there may already be an associated widespread metastasis. In this case report, a woman in her forties with a history of breast cancer was found to have widespread metastases, including in the pancreas. The patient was treated with chemotherapy and hormonal therapy. [ABSTRACT FROM AUTHOR]

Context: The impaired ability of thyroid cancer (TC) cells to uptake and concentrate iodine represents a major therapeutic challenge in malignant TC management. This has been reported probably due to reduced or loss of expression of pendrin in thyroid tumors. Aims: In view of this, we evaluated the pendrin expression in the chemically induced (using N-bis[2-hydroxypropyl] nitrosamine [DHPN]) TC model in Wistar rats. Methods: Uptake in the thyroid gland was evaluated by positron emission tomography with computed tomography (PET-CT) and scintigraphy imaging. Further histopathology (HP) and immunohistochemistry (IHC) were performed for confirming malignancy. Results: The altered uptake in the thyroid gland was observed by PET-CT and scintigraphy imaging. Significant pathological changes in the thyroid were observed using 2-deoxy-2-(fluorine-18) fluoro-D-glucose PET-CT, technetium-99m pertechnetate imaging, and reduced iodine-131 uptake (n = 4) in DHPN-induced animals compared to control indicative of thyroid cell proliferation. In treated groups, tissue HP revealed hyperplastic follicular to papillary cell proliferation with variable mitotic activity. The malignant nature of the tissue and variable uptake of the tracer were further reconfirmed by IHC. IHC revealed reduced pendrin expression in malignant thyroid tissue. Conclusions: Hence, nuclear imaging techniques can be of aid in the early identification and evaluation of cellular changes during the early development of tumor models in laboratory animals. In conclusion, our study reveals that pendrin expression plays a vital role in thyroid uptake, and its reduction was observed in TC in a chemically induced TC model. [ABSTRACT FROM AUTHOR]

Primary leiomyosarcoma of bone (PLB) is a rare tumor, constituting <0.7% of all primary bone malignancies. It is clinically aggressive with heterogeneous presentation and a dismal prognosis. The most common presentation is pain with swelling and pathological fracture at times. Limited literature is available on PLB and only about 150 cases have been reported to date with only a few case reports defining the utility of 18F‑fluorodeoxyglucose (18‑F FDG) positron emission tomography/computed tomography (PET-CT) in its management. We hereby present a case of primary leiomyosarcoma of the right distal femur and the role of FDG-PET-CT in its management. [ABSTRACT FROM AUTHOR]

Solitary fibrous tumor (SFT) of the central nervous system (previously called hemangiopericytoma) is a rare mesenchymal tumor. Malignant SFT has a tendency to recur after surgery and can metastasize to distant organs. Treatment options for metastatic disease are limited. This case demonstrated high expression of FAP (fibroblast activating protein) in all metastatic sites with Ga-FAPI positron emission tomography-computed tomography imaging. Subsequently, the patient was treated with Lu177-FAPI-targeted radionuclide therapy. There was significant clinical response. There was mild partial morphological response seen on follow-up imaging. [ABSTRACT FROM AUTHOR]

Introduction: The objective of this study was to compare 99mTc MIBI myocardial perfusion SPECT and Dobutamine Stress Echocardiography (DSE) in detecting viable myocardium in patients with Coronary Artery Disease. Materials and Methods: Total of 50 patients who with CAD and poor LV function were idenitifed on 2D Echo using 16 segment cardiac model. These patients underwent 99mTc MIBI myocardial perfusion SPECT and Dobutamine Stress Echocardiography and the results were compared with the gold standard 18F-FDG PET-CT findings. Results: A Total of 550 dysfunctional segments were identified in datasets of 50 patients on 2D echo. No significant difference was noted between the pairwise positive outcome of viable segment between MIBI SPECT and DSE (p=0.875). MIBI SPECT showed a sensitivity of 86.5% and specificity of 90.0% when compared with 18F-FDG PET-CT which was comparable with DSE having a sensitivity of 87.6% and specificity of 90.7%. Conclusion: 99mTc MIBI SPECT is an effective good alternative for evaluation of viable myocardial segments in patients with dysfunctional myocardium and can be considered especially in elderly or obese patients and patients with lung disease having poor echocardiographic imaging window due to lack of an optimal acoustic window. [ABSTRACT FROM AUTHOR]

Aims: The aim of this study was to evaluate the role of 18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) scan in the detection of axillary lymph node (ALN) involvement and comparison with sentinel lymph node biopsy (SLNB) in operable early-stage breast cancer (EBC). Settings and Design: It is a retrospective analysis of staging PET-CT scan of EBC. Methods: A total of 128 patients with histopathologically proven breast cancer (BC) were included in the study. Preoperative mammography supplemented with ultrasonography and staging 18F-FDG PET-CT scan was done for all patients. Surgery was done within 30 (mean ± standard deviation = 13.8 ± 10.5) days of staging. SLNB was performed in patients without PET-positive ALNs. All patients with positive sentinel nodes and PET-positive ALNs underwent axillary lymph node dissection (ALND). Statistical Analysis Used: The comparison between categorical variables was made by Chi-square/Fisher's exact test as applicable. For continuous variables comparisons, Student's t-test and one-way analysis of variance tests were used. Results: Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of PET-CT scan for detection of ALN involvement were 41.7%, 93.2%, 92.1%, and 45.6%, respectively. Sensitivity, specificity, PPV, and NPV of mammography were 84.5%, 54.5%, 78.0%, and 68.6%, respectively. Sixteen out of 46 (34.7%) patients with negative ALNs in PET-CT scan finally showed involvement in histopathology report after SLNB resulting in upstage of the disease. The size of tumor deposits in sentinel nodes was significantly smaller than PET-positive ALNs (P = 0.01). Our observations correlate with the results of earlier studies published in the literature. Conclusions: 18F-FDG PET-CT scan cannot substitute SLNB for ALN screening in EBC. The limitations are most marked in smaller and micrometastatic tumor deposits in ALNs and may be attributed to limitations of PET resolution. However, PET-positive nodes showed good specificity for disease involvement in our study. Therefore, ALND can safely be performed by omitting SLNB in such cases. [ABSTRACT FROM AUTHOR]

Introduction: Successful surgical treatment for primary hyperparathyroidism requires accurate localization of abnormal parathyroid tissue in terms of location and number. Imaging is important for localizing the parathyroid adenoma, and there has been significant interest in 18F-fluorocholine (FCH) positron emission tomography/computed tomography (PET/CT) for this purpose. Aim: This study attempted to ascertain the utility of 18F-FCH PET/CT as a first-line investigation in preoperative localization of abnormal parathyroid tissue in primary hyperparathyroidism, in comparison with 99mTc-sestamibi dual-phase scintigraphy with early single-photon emission computed tomography (SPECT)/CT and neck ultrasonography. Materials and Methods: Fifty-five patients with biochemical features of primary hyperparathyroidism were enrolled in this study. They underwent neck ultrasonography, 99mTc-sestamibi dual-phase scintigraphy with early SPECT/CT, and 18F-FCH PET/CT for localization of parathyroid lesions. Thirty-three patients underwent surgical resection of the detected lesions. For two patients, clinical and biochemical follow-up was used as a gold standard. Results: A total of 40 lesions were resected in the 33 patients who underwent surgery. A further two lesions were localized in two patients with clinical and biochemical follow-up as the gold standard. Of these 42 lesions, 41 were detected in preoperative imaging and 1 lesion was noted intraoperatively and resected. 41/42 lesions were detected by 18F-FCH PET/CT (detection rate: 97.6%), 33/42 by 99mTc-sestamibi dual-phase scintigraphy with early SPECT/CT (detection rate: 78.5%), and 30/42 by neck ultrasonography (detection rate: 71.4%). Conclusion: Detection rates on 18F-FCH PET/CT were superior to both 99mTc-sestamibi dual-phase scintigraphy with early SPECT/CT and neck ultrasonography in preoperative localization of parathyroid lesions in patients with primary hyperparathyroidism. [ABSTRACT FROM AUTHOR]

Diagnosis of cardiac infections, which includes infective endocarditis (IE) and cardiac device infections, despite having a high death rate, is still challenging. Frequently used modalities such as echocardiography, computed tomography (CT), and magnetic resonance imaging cannot confirm the presence of an active infection or extracardiac findings. Taking these things to consideration, newer guidelines have suggested the inclusion of 18F fluorodeoxyglucose positron emission tomography/ CT (18F FDG PET/CT) in the workup of patients with suspected prosthetic valve IE. In this pictorial essay, we are demonstrating the utility of 18F-FDG PET/CT in varied cases of IE, cardiac implantable electronic devices, and coronary stent infection and how they helped in solving diagnostic dilemmas. [ABSTRACT FROM AUTHOR]

Erdheim–Chester disease (ECD) is a systemic histiocytosis that can involve several organs, with severity ranging from occult to life-threatening. The disease was first described by William Chester in 1930 after working with the Austrian pathologist Jakob Erdheim. Even today, a correct diagnosis of ECD often takes years, given the rarity and variable manifestations of ECD. We present a case of a 63-year-old female presenting with multiple brain lesions, sent for fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography to find primary, and it showed hypermetabolic right occipital brain lesion, right orbital lesion, and soft tissue around the arch of the aorta (coated aorta), and final histopathology of the brain lesion confirmed histiocytosis ECD. [ABSTRACT FROM AUTHOR]

Context: Positron emission tomography (PET) using F-18 fluorodeoxyglucose (FDG) for treatment monitoring in patients with lymphoma is one of the most well-developed clinical applications. Deauville five-point score (DS) is recommended for response assessment in international guidelines. DS gives the threshold for adequate or inadequate response to be adapted according to the clinical context or research question. Aims: We aimed to validate DS in Hodgkin's lymphoma (HL) by retrospectively assigning this score to F-18 FDG PET-computed tomography (CT) studies done before 2016 and analyzing its concordance with the line of management. The secondary aim was to assess the reproducibility of DS in the interpretation of PET-CT scans. Subjects and Methods: A total of 100 eligible consecutive patients underwent F-18 FDG PET-CT scans between January 2014 and December 2015. Their interim, end of treatment, and follow-up PET scans were retrospectively visually analyzed and assigned DS by three nuclear medicine physicians. Concordance was defined as agreement between the DS assigned and the line of treatment. Interobserver variability was calculated using weighted Kappa and presented with 95% confidence interval. Results: Among 212 scans assigned DS, 165 scans showed agreement between the DS and line of treatment. Of these, 95.2% of scans scored DS 1-3 were kept on following or the same treatment plan was continued and patients did well. Among the scans that showed discordance, 24 scans scored DS 4/5 were continued on the same treatment regimen and the next assessment showed disease progression. Conclusions: Our study confirmed that DS is a useful tool to aid in reporting F-18 FDG PET-CT in the management of HL with good positive and negative predictive values. This study also demonstrated good interobserver agreement. [ABSTRACT FROM AUTHOR]

Burkitt's lymphoma (BL) is a highly aggressive type of B-cell non-Hodgkin lymphoma. BL commonly occurs in children of age 4-7 years and is uncommon in adults, with a worse prognosis. Patients often present with a rapidly growing mass typically involving the abdomen (liver and spleen) and head and neck (nodes, jaw, and facial bones). Pancreas involvement is very rare and very few case reports have been documented so far. Fluorine-18 positron emission tomography/ computed tomography (F-18 PET/CT) is a whole-body survey commonly used for initial staging evaluation. Here, we present an interesting case of BL in an adult female of 43 years, who presented with swelling in the left submandibular region after tooth extraction with multiorgan involvement found on F-18 fluorodeoxyglucose PET/CT. [ABSTRACT FROM AUTHOR]

Neurolymphomatosis is rarely encountered in high-grade lymphomas. In this case series, we retrospectively analyzed six neurolymphomatosis cases to look for possible risk factors, common and uncommon presentations, and the lessons learned. Neuropathic pain was the most common symptom with mono or polyradiculopathy in this series. However, all lymphomatous infiltrated nerves diagnosed on fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) were not symptomatic. The lumbar, brachial plexus, and trigeminal nerve were the most common sites and were depicted well on FDG PET/CT. Magnetic resonance imaging (MRI) of the brain better delineates cranial nerves and meningeal involvement. Cerebrospinal fluid flow cytometry was normal until meninges were involved. FDG PET/CT incrementally evaluated extra-neural disease sites, thus helping in deciding biopsy sites and further management. We concluded that a whole-body FDG PET/CT including limbs with MRI brain was the appropriate investigation for evaluating suspected neurolymphomatosis in advanced-stage diffuse large B-cell lymphoma. [ABSTRACT FROM AUTHOR]

Laparoscopic cholecystectomy is a fairly common procedure and is currently considered the gold standard for cholecystectomy. However, the laparoscopic procedure in the presence of gall bladder cancer (GBC) is associated with the risk of port-site metastasis (PSM). Furthermore, in few cases, GBC remains occult even on postoperative histopathology and presents with PSM remotely. Here, we describe two such cases of GBC with occult primary who presented with PSM and also defined the role of fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography in the management of such cases. [ABSTRACT FROM AUTHOR]

Primary thyroid lymphoma (PTL) is an uncommon malignancy. The majority of PTLs are non-Hodgkin's lymphoma. Fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) is the state-of-the-art imaging in lymphoma and plays a pivotal role in staging, follow-up, and treatment decisions. There is good evidence that it performs well in a wide variety of nodal and extranodal lymphomas (ENL). However, the data are scarce on its usefulness in rare ENL. Herein, we describe four cases of PTLs and a brief review of the literature. FDG PET/CT was performed at baseline to assess the disease status and response to treatment. This case series highlights the varied appearance of PTL and response to treatment. It establishes the importance of FDG PET/CT in the personalized management of PTL. [ABSTRACT FROM AUTHOR]

Aim: 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/ CT) is useful in the evaluation of lung cancer (LC), both for staging and therapy assessment. However, for the evaluation of treatment response, shared criteria are not available. We proposed a 3-point score, similar to Deauville-score and compared its diagnostic accuracy with Hopkins criteria for the evaluation of treatment response in LC to validate a qualitative and simpler interpretation system. Methods: We retrospectively included 93 patients with advanced stage (III-IV) LC who underwent 18F-FDG-PET/CT after first-line treatment. Positron emission tomography/computed tomography (PET/CT) scans were interpreted according to a 3-point scale-like Deauville score criteria (score 1 = uptake lower than blood-pool activity; score 2 = uptake higher than blood-pool but lower than liver activity; score 3 = uptake higher than liver). Inter-reader variability was assessed using percent agreement and kappa statistics. Kaplan--Meier plots with a Mantel-Cox log-rank test were performed, considering death as the endpoint. Results: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of like Deauville-like score criteria were 82,76% (95% confidence interval [CI] 70.5%-91.4%), 80% (95% CI 28.3%-99%), 97.9% (95% CI 89.2%-99.6%), 28.6%(95% CI 16.38%-44.9%), and 82.5% (95% CI 70.9-90.9%), respectively. Applying Hopkins criteria score we obtained sensitivity, specificity, PPV, NPV, and accuracy of 81% [95% CI 68.6%--90.1%), 100% (95% CI 47.2-100%), 100% (95% CI %), 31.3% (95% CI 21.0%-43%), and 82.5%(95% CI 70.9%-90.9%), respectively. There was a high agreement between the two readers both using Hopkins criteria (k = 0.912) and like-Deauville-score criteria (k = 0.956). Applying 3-point-scale criteria, patients with positive PET/CT after therapy had significantly shorter lower survival (P = 0.0021). Conclusion: The application of 3-point scale criteria for posttherapy assessment in patients with advanced stage of LC represents an easy and reproducible method with optimal inter-observer agreement and great PPV and accuracy. [ABSTRACT FROM AUTHOR]

A diverticulum is an outpouching of a hollow (or fluid-filled) structure in the body. They are most commonly seen in the urinary bladder, intestine, and pharyngeal region and are rarely seen in renal calyces. They are usually benign, asymptomatic, and are coincidentally detected. Due to their nonspecific clinical and radiological picture, sometimes they mimic malignant tumors, leading to misdiagnosis and treatment. We are presenting a case of 60-year-old female with right breast carcinoma, on whole body 18-fluorodeoxyglucose positron emission tomography-computed tomography; we observed an interesting finding in the right renal region mimicking renal metastasis. [ABSTRACT FROM AUTHOR]

Ga-68 labeled prostate-specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET/CT) is increasingly recognized as the best imaging modality for disease staging and detection of recurrent prostate cancer. Despite its name, PSMA expression has been reported in the neovasculature of several nonprostatic benign and malignant pathologies. Docetaxel, a taxane antineoplastic agent, is the mainstay of treatment in castration-resistant prostate cancer and high-volume hormone-sensitive prostate cancer. Although the occurrence of docetaxel-related interstitial lung disease is rare, it may lead to respiratory failure if treatment is delayed. We present a case of metastatic castration-resistant prostate cancer, wherein docetaxel-induced interstitial pneumonitis was detected on Ga-68 PSMA PET/CT after docetaxel administration. [ABSTRACT FROM AUTHOR]

Carcinoma en cuirasse is a type of cutaneous metastasis from different malignancies. En cuirasse although is a rare entity, most commonly occurs in cases of recurrent breast carcinoma after surgery or very rarely months or years after diagnosis of primary tumor. We report a rare case of neck carcinoma en cuirasse in a 47‑year‑old Indian female who is a known case of recurrent carcinoma left breast postmodified radical mastectomy, chemotherapy, and radiotherapy referred for fluorodeoxyglucose positron emission tomography–computed tomography following another six cycles of chemotherapy for response assessment [ABSTRACT FROM AUTHOR]

A 75‑year‑old male with head‑and‑neck squamous cell cancer received a staging f‑18‑fluorodeoxyglucose (18F‑FDG) positron emission tomography‑computed tomography (PET/ CT) scan which showed additional focal abnormal uptake in the right hepatic lobe. The patient was treated for probable metastatic disease. Restaging FDG PET/CT scan revealed resolution of uptake in the head‑and‑neck and persistent focal uptake in the presumed liver metastasis. An abdominal CT with intravenous contrast revealed an enhancing mass in the gallbladder, without extension into the liver. Cholecystectomy revealed an intracholecystic papillary neoplasm of the gallbladder. The initial appearance of hepatic metastasis was due to a misregistration artifact. [ABSTRACT FROM AUTHOR]

Recurrent pericardial effusion poses a diagnostic challenge, especially in young patients. We present a case of a 22-year-old female who experienced recurrent pericardial effusion and cardiac tamponade. Despite initial treatment with anti-tubercular drugs and prednisolone, the patient had a relapse of symptoms, necessitating further investigation. Imaging studies revealed massive pericardial effusion with septations, suggestive of constrictive pericarditis with impending cardiac tamponade. To establish a definitive diagnosis, the patient underwent an FDG PET-CT scan after adhering to a specific dietary regimen. The scan revealed an ill-defined mediastinal mass with high metabolic activity, along with a gross pericardial effusion showing metabolic activity in the periphery and septations. Subsequent biopsy of the mediastinal mass confirmed a diagnosis of high-grade sarcoma.Primary malignant cardiac tumors are rare, and their prognosis is generally poor due to limited treatment options. While echocardiography and MRI are commonly used imaging techniques, FDG PET-CT is not routinely employed for evaluating cardiac tumors. However, in this case, FDG PET-CT played a crucial role in identifying the mediastinal mass and confirming the diagnosis. Early detection and accurate diagnosis of cardiac tumors are vital for initiating appropriate treatment strategies. Further studies are needed to explore the utility of FDG PET-CT in the evaluation of cardiac tumors, especially in cases of recurrent pericardial effusion. [ABSTRACT FROM AUTHOR]

Background: Imaging of gliomas/glioblastomas has always been challenging. Many magnetic resonance imaging (MRI) techniques are available for imaging glioblastomas. MRI cannot always differentiate tumor from nonspecific changes and postoperative changes in brain tissue. Among the new positron emission tomography-computed tomography (PET-CT) tracers, gallium-68 prostate-specific membrane antigen (Ga-68 PSMA-11 PET-CT) appears to be the most promising one. The absence of uptake by normal brain parenchyma leads to high tumor-to-background ratio leading to better visualization of the tumor. Objective: The aim of this study was to assess the correlation of target volumes on MRI and PSMA brain scans in the treatment planning of glioblastomas. Materials and Methods: Twenty-four patients in the age group of 5-75 years with histologically proven glioblastoma were included in the study following maximum safe resection. Simulation for treatment planning was done with Ga-68 PSMA PET-CT brain with IV iodine-based contrast. The pre- and postoperative MRI images were fused with PSMA simulation images. Gross tumor volumes (GTVs) contoured on T1-contrast MRI and on PSMA scans were compared. Results: GTV contoured on MRI and PSMA brain scans showed complete overlap in 17 patients. In seven patients, the target volumes drawn on Ga-68 PSMA brain scans were slightly smaller than the target volumes drawn on MRI brain scans. This difference in volumes could be due to postoperative changes which showed enhancement on the MRI scan. Conclusion: Ga-68 PSMA PET-CT shows good correlation with MRI brain in the evaluation and RT planning in glioblastomas. Tumor necrosis and postoperative changes did not show PSMA uptake. Precise target delineation on PSMA PET-CT can potentially result in smaller and more accurate GTVs, which in turn would result in less RT-induced side effects. [ABSTRACT FROM AUTHOR]

Purpose: Adrenocortical carcinoma (ACC) is a rare primary malignancy of the adrenal gland. The present study was aimed to compare the performance of fluoro-2-deoxyglucose-positron emission tomography-computed tomography (FDG-PET-CT) compared to contrast-enhanced computed tomography (CECT) in diagnosis and management of ACC. Materials and Methods: A retrospective analysis of the PET-CT studies from January 2010 to October 2020 was performed. Patients with adrenal lesions suspicious of ACC and diagnosed cases of ACC who underwent PET-CT for staging, restaging, and surveillance were reanalyzed. The PET-CT parameters were compared with the clinical, biochemical, histopathological, and CECT parameters. Results: The study included 96 scans performed in 77 patients (36 males, aged 40.4 ± 17.9 years). Of these, 55 scans were performed to diagnose and stage suspected ACC (30 of them diagnosed as ACC), 31 for restaging, and 10 scans for surveillance of ACC. PET/CT revealed metastases from an extra-adrenal primary in 5/55 patients. FDG-PET-CT had a sensitivity and specificity of 100% and 70% to diagnose ACC. Standardized uptake value-peak more than 5.4 had a sensitivity of 90.9% and specificity of 91.7% for differentiating ACC from non-ACC lesions, while tumor-to-liver ratio peak (TLRpeak) of 3.3 was most specific. PET-CT changed the staging in 23.3% of the patients with an accuracy of 100%. PET-CT changed the management plan in 25.8% of the patients during restaging with a sensitivity and specificity of 95.6% and 100%, respectively. For surveillance, CECT was as sensitive as PET-CT; however, PET-CT was more specific (100% vs. 97.9%). Conclusion: FDG-PET-CT performs better than CECT in the diagnosis, staging, restaging, and surveillance of ACC. [ABSTRACT FROM AUTHOR]

We report a rare case of nocardiosis with increased F-18 Fludeoxyglucose (F-18 FDG) uptake in widespread abscess foci of Nocardia farcinica infection in an immunocompromised patient on positron emission tomography computed tomography (PET/CT) imaging. A relatively infrequent cause of nocardiosis, N. farcinica is an opportunistic infection that may present with clinically aggressive disseminated disease. Whole-body F-18 FDG-PET/CT allows identifying the extent of disease, as well as monitoring response to therapy in patients with nocardiosis especially the disseminated form. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) has a high mortality rate due to the diagnosis of patients at advanced stages and ineffective systemic therapies. Immunotherapy is considered a new treatment option for unresectable HCC alternatives to the limitations of conventional cytotoxic chemotherapy. In this case report, we reported that transarterial radioembolization and immunotherapy such as atezolizumab and bevacizumab can be used together in a manner effectively in the management of HCC treatment. [ABSTRACT FROM AUTHOR]

Background: Retinoblastoma (RB) is the most common primary intraocular malignancy of childhood. Magnetic resonance imaging (MRI) of the orbit and brain is the preferred imaging modality to diagnose and define extent of disease as well as to assess response to therapy. Sometimes, it may be difficult to differentiate the presence of active residual disease from therapy-related changes based on posttreatment completion MRI. Materials and Methods: RB patients who completed treatment between January 2017 and October 2019 were retrospectively analyzed. We evaluated the utility of F-18-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) to predict active disease in RB patients who continued to have residual disease on MRI at completion of treatment. Results: Out of the 89 patients who completed treatment, dilemma regarding remission status was present in 11 children. All 11 patients underwent FDG-PET-CT. None of them had evidence of metabolically active disease in the orbit, optic nerve, brain, or rest of the body. After a median follow-up of 24 months, no children developed any evidence of disease progression in the form of local or distant relapse. Conclusion: Our results showed that in MRI doubtful cases, a nonavid FDG-PET is reassuring in avoiding further therapy as long as close follow-up can be ensured. FDG-PET-CT may emerge as a useful functional modality to predict disease activity in RB. [ABSTRACT FROM AUTHOR]

Objective: Ex vivo radioactivity measurement of positron emission tomography/computed tomography (PET/CT)-guided biopsy tissue specimen to check the viable tumor sampling and predict the nature of the biopsied lesion. Materials and Methods: We prospectively evaluated the retrieved tissue specimens during PET/CT-guided biopsies for the presence of radioactivity. The qualitative radioactivity was measured by acquiring PET/CT images of the specimen. For quantitative analysis, a multichannel-analyzer (MCA) was used, and a counting-factor (CF) in counts/mCi.mm³ was calculated based on background-corrected net-counts, tissue-volume (mm³), and exponential tracer-activity during biopsy (mCi). The CF-values were compared with the 2-(fluorine-18) fluoro-2-deoxy-D-glucose-avidity in the target lesion and correlated with the histopathology. Results: A total of 49 patients (30 males) aged 51.8 ± 17.8 years were recruited for the biopsy, and radioactivity was measured. All the specimens revealed the presence of radioactivity on PET/ CT images of the specimens and MCA counting. The mean CF-values were 17.2 ± 15.6 counts/mCi. mm³. One sample had meager counts with a CF-value of 0.162 and was subjected to re-biopsy after repositioning the coaxial needle to the hypermetabolic site. Pathological diagnosis was established in all the patients (malignancy-29, benign-20). The CF-values were significantly higher in malignant lesions than benign (21.45 ± 18.05 vs. 10.76 ± 8.96 counts/mCi.mm³, P = 0.025). CF-values and maximum standardized uptake value had a significant correlation (Pearson's r = 0.457, P = 0.001). Conclusion: The ex vivo measurement of the radioactivity of retrieved tissue specimens during PET/CT-guided biopsy helps to confirm the sampling from viable region and a highly practical approach to avoid erroneous sampling of a lesion with a large necrotic area. It is also helpful in predicting the nature of the biopsied lesion before the histopathological analysis. [ABSTRACT FROM AUTHOR]

Primary ovarian lymphoma is a rare malignancy with <1% incidence. Plasmablastic lymphoma usually associated with immunocompromised diseases such as HIV rarely involves the ovary; only two case studies are reported in the literature - plasmablastic lymphomatous involvement of an ovarian teratoma and another of plasmablastic variant of B-cell lymphoma involving bilateral ovaries. There are reported case series of synchronous presentation of carcinomas usually including lung, stomach, and colon and nonaggressive lymphomas. Here, we report a rare case of synchronous aggressive primary plasmablastic ovarian lymphoma with adenocarcinoma of the lung, both of which are associated with immune-compromised conditions. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to evaluate the radiation exposure to patients undergoing positron emission tomography/computed tomography (PET/CT)-guided biopsies. Materials and Methods: Patients undergoing PET/CT-guided biopsy were recruited prospectively from October 2019 to April 2020. PET/CT-guided biopsy from a tracer avid site was done using an automated-robotic-arm 1 h after intravenous injection of F-18-fluorodeoxyglucose (FDG) (2-5 mCi) or Ga-68-PSMA (1-4 mCi). Regional CT-images were acquired for biopsy planning and confirmation of needle placement. The internal radiation exposure due to the PET component was estimated using the value of activity injected and dose-coefficient for FDG and PSMA. The external radiation exposure due to the CT component was estimated using the value of dose length product and organ coefficients conversion factor. The total effective dose during the procedure was calculated by adding exposure due to both CT and PET components. Percentage contribution from CT and PET component to total effective dose was compared using a paired t-test. Results: A total of 101 patients (76 males) were recruited for PET/CT-guided biopsy using FDG (n = 79) and PSMA (n = 22). The mean effective-dose due to PET and CT components and total effective-dose was 2.49 ± 1.02 mSv, 2.35 ± 1.03 mSv and 4.83 ± 1.90 mSv, respectively, for FDG-guided procedures and 1.60 ± 0.57 mSv, 3.06 ± 1.36 mSv, and 4.66 ± 1.37 mSv for Ga-68-PSMA-guided procedures. The percentage contribution of PET and CT in total effective-dose was comparable in F-18-FDG and Ga-68-PSMA PET/CT-guided biopsy procedures; however, for Ga-68-PSMA PET/CT-biopsies, CT contributed a higher radiation dose than PET component. Conclusion: PET/CT-guided biopsy is a safe interventional procedure, and radiation exposure to the patients was less than routine whole-body PET/CT-imaging. [ABSTRACT FROM AUTHOR]

A 61-year-old male underwent fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) for evaluation of fever and weight loss with clinical suspicion of occult malignancy or tuberculosis. The scan showed hypermetabolism in bilateral submandibular salivary glands, biliary radicles, pancreas, bilateral kidneys, prostate, and multiple lymph nodes. Based on the concomitant involvement of these sites, suspicion of immunoglobulin G4 (IgG4)-related disease was raised in PET-CT report. Further evaluation with serum IgG4 levels and histopathology of the submandibular salivary gland confirmed the diagnosis of IgG4-related disease. The ability of FDG PET-CT to evaluate the whole-body status of disease played a crucial role in this case. [ABSTRACT FROM AUTHOR]

High 18F-Fluorodeoxyglucose (18F-FDG) uptake in a cardiac mass is considered to be a marker of malignancy, but that is not always true. We here present such a case of incidentally detected 18F-FDG cardiac mass on staging positron emission tomography-computed tomography in a woman with head-and-neck cancer, confirmed to be myxoma on contrast-enhanced magnetic resonance imaging and subsequent histopathology. [ABSTRACT FROM AUTHOR]

Primary lymphomatous involvement of spinal cord, nerve roots, and cauda equina is a rare entity and comprises only 0.1% of extra-nodal lymphoma spectrum. Here, we present a case of non-Hodgkin lymphoma involving cauda equina, initially suspected as ependymoma on magnetic resonance imaging that was later confirmed on nerve root biopsy as high B cell non-Hodgkin's lymphoma of L1-S1 nerve roots. F-18 fluorodeoxyglucose positron emission tomography-computed tomography was performed for staging workup which showed abnormal metabolic activity within the spinal canal from D10-S2 with no evidence of distant organ involvement. [ABSTRACT FROM AUTHOR]

Aim: This study aims to study the clinical-diagnostic relevance of incidental breast uptake ("incidentaloma") on 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan performed for other indications and to correlate it with radiological imaging and histopathology. Materials and Methods: We retrospectively evaluated 3675 FDG-PET scans, identifying 43 patients with breast "incidentaloma." Thirty of these findings were further investigated with clinical examination, mammography (MMX), UltraSound (US) and/or magnetic resonance (MR). Cases suspected for malignancy underwent US-guided macro-biopsy (USMB) or MR-guided biopsy. Correlations between FDG-PET, radiology findings, age, and histopathology were evaluated. Results: patients who performed both US and MMX were 19. Ten consequently underwent USMB, one MR-guided biopsy, the remaining 8 were not further investigated. Nine patients had a diagnosis of malignancy. Among 11 patients who performed only US and consequently, USMB 6 had a diagnosis of malignancy. Histopathology of the 22 patients with both morphological and glucometabolic alterations showed different types of benign or malignant neoplasia, with a cumulative 68.2% incidence of malignancy. Seven lesions showed a SUVmax >2.5, while the remaining 15 a SUVmax <2.5. There was no statistically significant correlation between SUVmax and histology, therefore SUVmax parameter should not be used to discriminate between benign and malignant findings. No significant correlation between patient age and tumor characterization was found. Conclusions: incidental mammary uptake during an FDG-PET scan may represent a clue suggesting to investigate PET findings. In this subset of patients, early diagnosis may lead to a change in clinical management with a favorable impact on prognosis and a significant reduction in healthcare costs. [ABSTRACT FROM AUTHOR]

Context: Extranodal (EN) lymphomas involve sites other than lymph nodes (LNs), spleen, thymus, and the pharyngeal lymphatic ring. The highest standardized uptake value (SUV) max of the LN can aid in the diagnosis of EN site lymphomatous infiltrations over inflammation or infection especially when there are no contrast-enhanced computed tomography (CT) changes. Aims: The purpose of this study was to find the significance of correlation between absolute SUVmax and mediastinal blood pool (mbSUVmax) and liver (lvSUVmax) normalized SUVmax of EN sites and the most fluorodeoxyglucose (FDG) avid LN in patients with primary and secondary EN involvement in Non-Hodgkin's and Hodgkin's Lymphoma. Settings and Design: This was a retrospective study of 70 patients with histopathologically proven lymphoma in whom 18F-FDG positron emission tomography CT was performed for pretherapy staging. Materials and Methods: Images were used to detect EN sites of disease and SUVmax of mediastinal blood pool, liver, highest SUVmax LN, and highest SUVmax EN site were calculated. Statistical Analysis Used: Karl Pearson's coefficient of correlation (r) was used to correlate the highest SUV max of LN and EN site and corresponding highest blood pool corrected and liver corrected SUV max. In view of small sample size, t-test for paired samples at 5% and 10% significance was conducted to validate the findings. Two-tailed t-test for independent samples was also used to compare means of SUVmax values between data grouped according to gender and lymphoma subtype (Non-Hodgkin lymphoma and Hodgkin lymphoma). Results: r = 0.54 for the highest LN SUVmax-highest EN SUVmax values and on further validation by one- and two-tailed paired t-test at significance levels of 5% and 10%, P = 0.00052 and 0.00103 respectively which denoted significant positive and moderate correlation. r = 0.59 for highest LN lvSUVmax-highest EN vSUVmax and P = 0.00032 and 0.00065 showing positive and moderate correlation. r = 0 0.82 for highest LN mbSUVmax-highest EN mbSUVmax values and P = 0.00034 and 0.00068 revealing positive and strong correlation. Conclusion: Significant positive and strong correlation exists between nodal and EN mbsUVmax. This is stronger than the correlation between nodal and EN absolute SUVmax and lvSUVmax. Since normalization of lesion SUVmax to reference tissues reduces the variability of SUV, this can be a useful adjunct to determine whether high SUVmax of the EN site is due to lymphomatous infiltration. [ABSTRACT FROM AUTHOR]

Objectives: The objective of this study was to evaluate the diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) and 68Ga prostate-specific membrane antigen positron emission tomography-computed tomography (PSMA PET-CT) and respective quantitative parameters (Ktrans - influx rate contrast, Kep - efflux rate constant, ADC - apparent diffusion coefficient, and SUVmax ratio - prostate SUVmax to background SUVmax ratio) in detection and localization of clinically significant prostate cancer (CSPCa) in D'Amico intermediate- and high-risk group patients (prostate-specific antigen [PSA] >10 ng/ml). Methodology: The study included thirty-three consecutive adult men with serum prostate specific antigen >10ng/ml, and systematic 12 core prostate biopsy proven prostate cancer. All the 33 patients, were evaluated with mpMRI, and 68Ga PSMA PET-CT. The biopsy specimens and imaging were evaluated for 12 sectors per prostate by a predetermined scheme. Results: MpMRI Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) score =3 showed higher sensitivity than 68Ga PSMA PET-CT (96.3% vs. 82.4%), with similar specificity (54.5% vs. 54.5%) (n = 33 patients, 396 sectors). Combined use of MRI and 68Ga PSMA PET-CT in parallel increased sensitivity (99.5%) and NPV (98.7%) for detection of CSPCa and combined use of MRI and 68Ga PSMA PET-CT in series increased specificity (71.8%) and PPV (71.5%) (n = 33 patients, 396 sectors). ADC showed a strong negative correlation with Gleason score (r = -0.77), and the highest discriminative ability for detection and localization of CSPCa (area under curve [AUC]: 0.91), followed by Ktrans (r = 0.74; AUC: 0.89), PI-RADS (0.73; 0.86), SUVmax ratio (0.49; 0.74), and Kep (0.24; 0.66). Conclusion: MpMRI PI-RADS v2 score and 68Ga PSMA PET-CT (individually as well as in combination) are reliable tool for detection and localization of CSPCa. Quantitative MRI and 68Ga PSMA PET-CT parameters have potential to predict Gleason score and detect CSPCa. [ABSTRACT FROM AUTHOR]

Objective: The objective is to evaluate incidental detection of COVID-19 lung involvement in asymptomatic individuals who undergo fluorodeoxyglucose (FDG) positron emission tomography-computerized tomography (PET/CT) scans for oncologic indications. Patients and Methods: The study was conducted in a tertiary care oncology hospital and included patients who were asymptomatic for COVID-19 infection and underwent FDG PET/CT scans for standard oncologic indications between April 15, 2020, and September 30, 2020. Patients who showed CO-RADS category 4/5 changes (high level of suspicion) on the CT chest component of the PET/CT study were considered for analysis. CT severity score, presence of FDG uptake, and maximum standardized uptake value of FDG avid lung involvement were noted and correlated with reverse transcriptase-polymerase chain reaction (RT-PCR) test. Results: 1982 PET/CT scans were performed, 78 (3.9%) patients showed lung changes with high degree of suspicion of COVID-19 pneumonia (CO-RADS 4/5). Hematolymphoid and head-neck cancer were the most common tumor types (23%), and restaging/response evaluation was the most common PET/CT indication. Of the patients who underwent RT-PCR testing, 70% showed a positive result. The mean CT severity score was 6 (standard deviation 5.9) with no significant difference seen between the RT-PCR positive and negative groups. FDG avidity in lung lesions was noted in 41 out 57 (72%) patients. A significant correlation was seen between the RT-PCR positivity and FDG uptake in lung lesions. Conclusion: A small but significant proportion of patients undergoing routine oncologic PET/CT scans showed incidental COVID-19 lung involvement. Lung involvement in these asymptomatic patients showed a low CT severity score in all patients and FDG avidity in majority. Timely detection of such incidental cases can initiate further confirmatory RT-PCR testing and isolation measures that not only influence patient's cancer treatment protocols but also have a larger community impact of limiting the spread of infection. [ABSTRACT FROM AUTHOR]

Bone and soft-tissue tumors display a wide range of metabolic activity on flurodeoxyglucose positron emission tomography/computerized tomography (FDG PET/CT) imaging due to their varying histopathological features. Several benign tumors show high FDG uptake similar to that seen in malignant lesions and their metabolic characteristics can overlap. Certain benign tumors can potentially undergo malignant transformation and FDG PET/CT can play an important role in detecting malignant change. The intensity of metabolic activity on FDG PET/CT correlates with histological grade of malignant tumors and also acts as a valuable prognostic factor. FDG PET/CT plays an important role in the staging work up of bone and soft-tissue malignancies. It has been found to be superior to conventional imaging techniques primarily for detecting distant metastatic disease. Because of its ability to detect metabolic changes, FDG PET/CT is a very useful in assessing response to treatment. Metabolic response seen on FDG PET is a powerful surrogate marker of histopathological response to chemotherapy. The purpose of this article is to study the variable patterns of FDG uptake in tumors of the musculoskeletal system, describe the clinical utility of FDG PET/CT in predicting malignant change in benign tumors and discuss its role in staging, response assessment, and prognostication of malignant lesions. [ABSTRACT FROM AUTHOR]

This pictorial essay depicts normal appearances, complications and residual or recurrent disease on fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) studies in the postsurgical and postprocedural setting, other than head and neck malignancy. Reading and reporting FDG PET/CT in this scenario is daunting due to the multiple confounding false positives seen during this period. This article which is the second part in this series will familiarize the readers with the normal appearance and pitfalls seen in FDG PET/CT studies in thoracic and abdominopelvic malignancies during the postoperative and postprocedural period so as to avoid misinterpretations. [ABSTRACT FROM AUTHOR]

Objective: Our study aims to establish the potential for tumor heterogeneity evaluated using 18F fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) texture analysis in nonsmall-cell lung carcinoma (NSCLC) patients who underwent platinum-based chemotherapy to provide an independent marker for overall survival (OS) of more than 1-year. Materials and Methods: A total of 42 patients (34 male and 8 female) with biopsy-proven NSCLC and mean age 55.33 ± 10.71 years who underwent a baseline F-18 FDG PET/CT and received platinum-based chemotherapy as first-line treatment were retrospectively included in the study. Ten first order, 21 s order texture parameters and 7 SUV and metabolic tumor volume (MTV) based metabolic parameters were calculated. All these parameters were compared between the two survival groups based on OS =1 year and OS <1 year. Cut-offs of significant parameters were determined using receiver operating characteristic curve analysis. Survival patterns were compared by log-rank test and presented using Kaplan-Meier curves. Cox proportion hazard model was used to determine the independent prognostic marker for 1 year OS. Results: In univariate survival analysis, 3 first order texture parameters (i.e. mean, median, root mean square with hazard ratios [HRs] 2.509 [P = 0.034], 2.590 [P = 0.05], 2.509 [P = 0.034], respectively) and 6 s order texture parameters (i.e. mean, auto correlation, cluster prominence, cluster shade, sum average and sum variance with HRs 2.509 [P = 0.034], 2.509 [P = 0.034], 3.929 [0.007], 2.903 [0.018], 2.954 [0.016] and 2.906 [0.014], respectively) were significantly associated with 1 year OS in these patients. Among the metabolic parameters, only metabolic tumor volume whole-body was significantly associated with 1 year OS. In multivariate survival analysis, cluster prominence came out as the independent predictor of 1 year OS. Conclusion: Texture analysis based on F-18 FDG PET/CT is potentially beneficial in the prediction of OS =1 year in NSCLC patients undergoing platinum-based chemotherapy as first-line treatment. Thus, can be used to stratify the patients which will not be benefitted with platinum-based chemotherapy and essentially needs to undergo some other therapy option. [ABSTRACT FROM AUTHOR]