Cardiac involvement in sarcoidosis: Evolving concepts in diagnosis and treatment

Clinically evident cardiac involvement has been noted in at least 2 to 7% of patients with sarcoidosis, but occult involvement is much higher (> 20%). Cardiac Sarcoidosis (CS) is often not recognized as an antemortem, as sudden death may be the presenting feature. Cardiac involvement may occur at any point during the course of sarcoidosis and may occur in the absence of pulmonary or systemic involvement. Sarcoidosis can involve any part of the heart. The prognosis of CS is related to the extent and site(s) of involvement. Most deaths due to CS are due to arrhythmias or conduction defects, but granulomatous infiltration of the myocardium may cause progressive and ultimately lethal cardiomyopathy. The definitive diagnosis of isolated CS is difficult and the yield of Endomyocardial Biopsies (EMB) is low. Treatment of CS is often warranted even in the absence of histologic proof. Radionuclide scans are integral to the diagnosis. Gadolinium-enhanced cardiac magnetic imaging scans and 18Fluorodeoxyglucose (18FDG)-Positron Emission Tomography (PET) are the key imaging modalities to diagnose CS. The prognosis of CS is variable, but mortality rates of untreated CS are high. Randomized therapeutic trials have not been done, but corticosteroids (alone or combined with additional immunosuppressive agents) are the mainstay of therapy. Additionally, anti-arrhythmic agents and therapy for heart failure are often required. Because of the potential for sudden cardiac death, an Implantable Cardioverter-Defibrillator (ICD) should be placed in any patient with CS and serious ventricular arrhythmias or heart block and should be considered for cardiomyopathy. Cardiac transplantation is a viable option for patients with end-stage CS refractory to medical therapy.

18FDG-Positron Emission Tomography in patients with Tuberculous Meningitis: A Prospective Evaluation

Lower yield of available diagnostic tests for tuberculous meningitis (TBM) frequently causes delay in diagnosis. Recently, 18F-fluorodeoxyglucose positron emission tomography (FDG PET) has been used in infectious disorders such as pulmonary tuberculosis; however, it is rarely used in TBM. This study was aimed to ascertain the role of FDG PET in the diagnosis and determination of the extent of disease and prognosis in patients with TBM. After excluding unsuitable patients, 25 patients were subjected to whole-body PET–computed tomography (CT) image acquisition along with separate brain protocol with an integrated PET-CT device. FDG PET was found to be abnormal in 92% patients. Extracranial FDG uptake was observed in 80% patients. Most common extracranial site of involvement was lymph nodes (60%), followed by lung (56%), vertebral body (8%), genitourinary organs (8%), and spleen (4%). FDG PET observed extracranial involvement had 80% sensitivity and 20% specificity in detecting definite TBM cases. In conclusion, FDG PET may be a useful test in TBM evaluation.

Choline PET/CT in Multiple Myeloma

The field of multiple myeloma (MM) imaging has evolved. The International Myeloma Working Group recently recommended performing 18F-fluorodeoxyglucose glucose (18FDG) positron emission tomography/computed tomography (PET/CT) with the aim of staging MM patients at baseline and evaluating response to therapy. Novel oncological radiotracers such as 11C-Choline and 18F-Fluorocholine, have been studied in comparison with 18FDG, mostly in MM patients presenting with refractory disease or suspected relapse. Choline-based tracers may overcome some limitations of 18FDG, which include a lack of sensitivity in depicting skull lesions and the fact that 10% of MM patients are FDG-negative. The majority of MM lesions display a higher uptake of Choline than FDG. Also, in many situations, Choline may offer better lesion visualization, with a higher tumor to background ratio; however, various patterns of Choline and FDG uptake have been observed in MM and some limitations, notably as regards liver lesions, should be recognized. Overall, Choline may provide additional detection of up to 75% more lesions. This article aims to provide a comprehensive review of the potential role of Choline in multiple myeloma, as compared to FDG, encompassing Choline physiopathology as well as data from clinical studies.