18F- FDG PET/CT in reclassifying the probable diagnosis of IE - A review.

In the diagnosis of infective endocarditis (IE), Modified Duke's criteria, coupled with clinical suspicion, serve as the guiding framework. For cases involving prosthetic valve endocarditis and infections affecting implantable devices, the use of metabolic imaging with 18 F-FDG PET/CT scans has gained prominence, as per the recommendations of the European Society of Cardiology guidelines. This imaging modality enhances sensitivity and specificity by identifying infective foci within the heart and extracardiac locations. Early utilization of these scans is crucial for confirming or ruling out IE, although caution is required to mitigate false positive responses, especially in the presence of ongoing inflammatory activity. A standardized ratio of ≥2.0 between FDG uptake around infected tissues and the blood pool has demonstrated a sensitivity of 100 % and specificity of 91 %. It is noteworthy that the sensitivity of FDG PET/CT varies, being lower for native valve and lead infections but considerably higher for prosthetic valve and pulse generator infections. This review provides a comprehensive overview of the advantages offered by FDG PET/CT in achieving a definitive diagnosis of IE.

Fluorine 18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Cardiac Viability Risk Stratification in Comparison with EuroSCORE II for Revascularization in Patients with Left Ventricular Dysfunction.

Background: Diagnostic value of fluorine 18-fluorodeoxyglucose positron emission tomography/computed tomography (F18-FDG PET/CT) in the assessment of myocardial viable segments is well known; hence, it can identify patients with left ventricular (LV) systolic dysfunction who may benefit from revascularization. The presence of significant myocardial viable segments before revascularization will offer better prognosis with reduced mortality and morbidity. However, the usage of F18-FDG PET/CT myocardial viability study in the presurgical risk stratification is limited. Objective: The objective of the study is to predict perioperative mortality with hibernating viable myocardial (HVM) segments established by F18-FDG PET/CT in comparison with EuroSCORE II in patients with LV dysfunction undergoing coronary artery bypass grafting surgery. Materials and Methods: A prospective, observational study included 75 patients of chronic ischemic coronary artery disease with ejection fraction ≤40%. Tc-99m sesta-methoxyisobutylisonitrile myocardial perfusion single photon emission CT/CT and myocardial viability with F18-FDG PET/CT at rest were performed. Mortality risk stratification was done according to the EuroSCORE II. Patients were followed for post-coronary artery bypass graft surgery (CABG) 30-day mortality. Mortality observed by HVM segment groups were compared with EuroSCORE II predicted mortality. Results: Receiver operating curve for 30-day mortality prediction with HVM segments and EuroSCORE II was constructed. It showed that a cutoff of <4 HVM segments (area under the curve [AUC] = 0.7) had a sensitivity of 85%, whereas EuroSCORE II (AUC = 0.4) had only 28.6% sensitivity. EuroSCORE II underestimated perioperative risk in patients with <4 viable segments, that is 5 times higher risk was observed in patients with <4 viable segments. Conclusions: HVM segments established by F18-FDG PET/CT had independently predicted mortality postoperatively. Hence, including F18-FDG PET/CT for viability assessment along with EuroSCORE II in preoperative risk assessment for revascularization by CABG in patients with LV dysfunction provided better risk stratification.

Genuine impact of 18F-fluorodeoxyglucose positron emission tomography with contrast-enhanced computed tomography in clinching the diagnosis and follow-up response assessment of vascular graft infections.

Vascular graft infection (VGI) is a rare and severe complication after vascular surgery associated with significant morbidity and mortality, but the diagnosis is not always straightforward due to its variable and nonspecific clinical signs. Computed tomography (CT) scan is considered to be the diagnostic tool of choice for advanced VGI, but there is a high incidence of false-negative results, especially in low-grade infections. 18F-Fluorodeoxyglucose positron emission tomography with contrast-enhanced CT (18F-FDG PET-CT) imaging can serve as an effective alternative tool for assessment of suspected VGI and also provide accurate anatomic localization of the infective focus. Here, we describe three cases of VGI with various clinical presentations where the site of infection was diagnosed, confirmed, and documented with the help of 18F-FDG PET-CT imaging.

Baseline Pancreatic Beta Cell Imaging After Pancreatic Transplantation Using Whole-Body 68Ga-DOTA-Exendin-4 PET/CT: A Spectrum of 2 Cases of Diabetes Mellitus.

Whole pancreatic transplant and islet cells transplantation are currently available strategies aiming toward diabetes cure. Beta cell specific noninvasive functional imaging using novel PET radiotracers are now available and can be used for beta cell imaging and quantification. Herein we describe a spectrum of 2 cases demonstrating beta cell targeted imaging using Ga-DOTA-exendin-4 PET/CT in patients with diabetes after simultaneous pancreas-kidney transplantation.

Incomplete form of Primary Hypertrophic Osteoarthropathy (Touraine-Solente-Gole Syndrome) Masquerading as Polyartrhalgia Diagnosed in Technetium-99m-Methylene Diphosphonate Scintigraphy: An Interesting Case Report.

The primary hypertrophic osteoarthropathy (PHOA) (pachydermoperiostosis) is a rare genetic/hereditary disease characterized by skin changes (pachydermia), clubbing of fingers and periosteal thickening (periostitis) with sub-periosteal new bone formation. Here we describe a case of an adolescent male who presented with clubbing and polyarthralgia. On evaluation with scintigraphy and SPECT-CT, he was diagnosed to have incomplete form of PHOA(skeletal manifestations without skin changes). The identification of incomplete form of primary hypertrophic osteoarthropathy which can be easily misdiagnosed as rheumatoid arthritis is discussed here.

Postrenal Transplant Allograft "Page Kidney" Identified and Salvaged using 99mTc-diethylenetriaminepentaacetic acid Renogram and Single-photon Emission-computed Tomography.

99mTc diethylenetriaminepentaacetic acid (DTPA) renogram is a commonly performed evaluation postrenal transplant to assess graft function and for early detection of suspected immediate and late transplant-associated complications. Although several modalities can be utilized to detect perinephric collection in posttransplant period, the utility of 99mTc DTPA single-photon emission-computed tomography (SPECT-CT) is not recognized. Herein, we discuss the incremental role of seldom considered SPECT-CT in early detection, leading to timely appropriate management and graft salvage in a case of posttransplant deteriorating renal allograft as a result of subcapsular hematoma.

Localized Pontine Uptake in Fluorine-18-Fuorodeoxyglucose Positron Emission Tomography/Computed Tomography in a Case of Hyponatremia: A Case Report and Review of Literature.

A rare acquired demyelinating lesion of the pons central pontine myelinolysis (CPM) typically occurs after rapid correction of hyponatremia. There is disruption of blood-brain barrier due to osmotic stress allowing access for inflammatory mediators in extravascular brain tissue, which most likely attracts glial cells of the brain, attracts macrophages, and activates astrocytes. We present a case of female with a known history of inflammatory bowel disease who presented with altered sensorium and hyponatremia. Fluorine-18-fuorodeoxyglucose (F-18-FDG) positron emission tomography/computed tomography (PET/CT) was performed which showed localized FDG uptake in the pons, consistent with the CPM findings observed on magnetic resonance imaging. Pontine uptake in F-18-FDG PET CT in hyponatremic patients who were clinically deteriotating even after correction of hyponatremic status aids for the diagnosis of CPM.

Contrast-enhanced [18F] fluorodeoxyglucose-positron emission tomography-computed tomography as an initial imaging modality in patients presenting with metastatic malignancy of undefined primary origin.

BACKGROUND: To evaluate the advantages of contrast enhanced F-18-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-contrast enhanced CT [CECT]) when used as an initial imaging modality in patients presenting with metastatic malignancy of undefined primary origin (MUO). MATERIALS AND METHODS: A total of 243 patients with fine needle aspiration cytology/biopsy proven MUO were included in this prospective study. Patients who were thoroughly evaluated for primary or primary tumor was detected by any other investigation were excluded from the analysis. Totally, 163 patients with pathological diagnosis of malignancy but no apparent sites of the primary tumor were finally selected for analysis. The site of probable primary malignancy suggested by PET-CECT was confirmed by biopsy/follow-up. RESULTS: PET-CECT suggested probable site of primary in 128/163 (78.52%) patients. In 30/35 remaining patients, primary tumor was not detected even after extensive work-up. In 5 patients, where PET-CECT was negative, primary was found on further extensive investigations or follow-up. The sensitivity, specificity, positive predictive value and negative predictive value of the study were 95.76%, 66.67%, 88.28% and 85.71% respectively. CONCLUSIONS: F-18 FDG PET-CECT aptly serves the purpose of initial imaging modality owing to high sensitivity, negative and positive predictive value. PET-CECT not only surveys the whole body for the primary malignancy but also stages the disease accurately. Use of contrast improves the diagnostic utility of modality as well as help in staging of the primary tumor. Although benefits of using PET-CECT as initial diagnostic modality are obvious from this study, there is a need for a larger study comparing conventional methods for diagnosing primary in patients with MUO versus PET-CECT.

(18)F-fluoro-deoxyglucose positron emission tomography-computed tomography in initial assessment and diagnosis of right atrial angiosarcoma with widespread visceral metastases: A rare case report and review of the literature.

Cardiac angiosarcoma is the most common primary cardiac sarcoma in adults. Primary cardiac tumors are rare and have nonspecific clinical presentation, thus making its diagnosis challenging. Clinically, patients present with advanced disease demonstrating metastatic disease at initial presentation itself. It commonly metastasizes to lung, liver, brain, and bone; however metastases to lymph nodes, adrenal glands, spleen and skin has also been seen. We describe a case of right atrial angiosarcoma with extensive visceral metastases involving brain, lungs, liver, pancreas, kidney, and lymph nodes, demonstrated on contrast-enhanced (18)F-fluoro-deoxyglucose positron emission tomography-computed tomography (FDG PET-CT). To the best of our knowledge metastases to pancreas and kidney have not been reported so far in the literature. With our report, we emphasize on the initial use of FDG PET-CT in workup of cardiac angiosarcoma for accurate staging and prognostication of this disease.

Monoarticular carcinomatous knee joint arthritis as an initial presentation of cervical carcinoma.

When it comes to cancer, one can expect the unexpected. The clinical presentations can be very bizarre. One of these uncommon presentations is monoarticular arthritis. The age group affected by cancer and arthritis are similar. However, the possibility of joint pain being secondary to metastatic involvement does not come to mind easily. In this report, a 65-year-old postmenopausal woman presented with complaint of pain and restricted movement of the right knee joint, in whom the clinical and magnetic resonance imaging features were suggestive of infective monoarthritis. However, synovial fluid aspirate showed presence of malignant cells. Hence, patient was evaluated with whole-body (18)F-fluorodeoxyglucose positron emission tomography computed tomography which detected primary malignancy of the cervix with regional nodal and right knee joint metastasis. To our knowledge, this is the first reported case of cervical malignancy with solitary skeletal metastasis involving the knee joint. The report also discusses overall incidence of malignant arthritis.