F-18 Fluciclovine PET-CT Findings and Pseudoprogression on Immunotherapy.

Immunotherapy plays a vital role in the treatment of several types of malignancies. While the molecular targets of immunotherapy differ, the desired goal is to increase the host immune response against neoplastic tissue. This upregulated immune state results in infiltration of the tumor with activated immune cells and may be misinterpreted as disease progression in anatomical and metabolic imaging studies, known as pseudoprogression. We present a case of pseudoprogression demonstrated on a fluoride-18 (F-18) fluciclovine positron emission tomography-computed tomography (PET-CT) scan of an 85-year-old male with metastatic castrate-resistant prostate cancer who underwent treatment with sipuleucel-T. An understanding of the pseudoprogression phenomenon and its manifestations is critical for both treating physicians and imaging specialists to facilitate decision-making regarding treatment.

ACR-ACNM Practice Parameter for the Performance of Fluorine-18 Fluciclovine-PET/CT for Recurrent Prostate Cancer.

The American College of Radiology (ACR) and American College of Nuclear Medicine (ACNM) collaborated to develop a clinical practice document for the performance of fluciclovine positron-emission tomography (PET) / computed tomography (CT) in the evaluation of patients with suspected prostate cancer recurrence based on the elevation of prostate-specific antigen (PSA) level (biochemical recurrence) after prior therapy. Prostate cancer is the third leading cause of cancer death in the United States. Up to 50% of patients diagnosed with prostate cancer will develop biochemical failure after initial therapy. The differentiation of local from extraprostatic recurrence plays a critical role in patient management. The use of functional imaging targeting features of cancer metabolism has proven highly useful in this regard. Amino acid transport is upregulated in prostate cancer. Fluciclovine (anti-1-amino-3-F-18-fluorocyclobutane-1-carboxylic acid, FACBC, Axumin™) is an artificial amino acid PET tracer which demonstrates utility in the diagnosis of recurrent prostate cancer with significant added value to conventional imaging.

Osmotic Demyelination Syndrome Revisited: Review With Neuroimaging.

Osmotic demyelination syndrome (ODS) is a general term that has become commonplace in the practice of medicine, encompassing both central pontine myelinolysis and extrapontine myelinolysis. Historically ODS arises as a serious complication of rapid correction of hyponatremia, yet its manifestations seem to be influenced by a multifactorial process. Further understanding of this rare demyelinating disease has elucidated the significant role of other electrolyte disturbances and the presence of chronic comorbidities as disease risk factors. This review discusses the current research regarding the pathophysiology, clinical manifestations, neuroimaging features, patient management, and prognosis of osmotic demyelination syndrome. We hope that this review will further endorse and aid in the proper diagnosis of ODS and its suitable management through the understanding of clinical and imaging correlations and outcomes, and the comorbid factors that may predispose the development of ODS in certain patient populations.

The potential of FDG PET/CT for early diagnosis of cardiac device and prosthetic valve infection before morphologic damages ensue.

Diagnosis of cardiac mechanical device or prosthesis valve infection, and more importantly accurate localization of the infection site, such as defibrillator pocket, pacemaker lead, annular or peri-annular valve ring abscesses remain clinically challenging. Inconclusive diagnosis can lead to delayed antibiotic therapy, device extraction or surgical intervention, which may have dire consequences to the patient. Among patients with suspected cardiac mechanical device or prosthetic valve infection, recent publications advocate the use of (18)F-fluoro-2-deoxyglucose positron emission tomography computed tomography (FDG PET/CT), particularly when anatomy based imaging studies, such as echocardiography or CT, are uncertain or negative. A potential advantage of FDG PET/CT is in its detection of inflammatory cells early in the infection process, before morphologic damages ensue. However, there are many unanswered questions in the literature. There is a need for standardization amongst the various imaging studies, such as dietary preparation, duration and timing of image acquisition, image processing with and without CT attenuation correction, and more importantly image interpretation criteria. The answer for these issues awaits well designed, prospective studies.

Role of FDG-PET in Evaluation of Myocardial Viability.

In many patients with chronic coronary artery disease, impaired left ventricular function at rest arises in part from regions of ischemic or hibernating myocardium rather than scarred myocardium. Evaluation of myocardial viability in heart failure allows for the prospective identification of patients with potentially reversible left ventricular dysfunction in whom prognosis may be favorably altered with coronary artery revascularization. This article reviews the role of F18-fluorodexyglucose PET myocardial viability testing in the management of patients with chronic left ventricular dysfunction and in guiding therapeutic decisions for revascularization.