Lynne Koweek

Utility of FDG PET/CT in Inflammatory Cardiovascular Disease

Inflammatory disorders of the cardiovascular system can affect the myocardium, pericardium, or vessel walls. Patients with myocardial and pericardial disease may present with chest pain, palpitations, and shortness of breath, symptoms resembling myocardial ischemia or infarction. The manifestations of vasculitis may include fever, weight loss, and fatigue, mimicking infectious or malignant processes. Because of the difficulty of differentiating these disease processes, patients frequently undergo multiple diagnostic examinations before obtaining a final diagnosis of myocarditis, pericarditis, or vasculitis. Computed tomography (CT) and magnetic resonance imaging play important roles in the assessment of structural abnormalities of the cardiovascular system, and combined positron emission tomography (PET) and CT may depict inflammatory processes before structural changes occur. Familiarity with the PET/CT appearances of inflammatory processes in the myocardium, pericardium, and vessels is important for accurate and prompt diagnosis.

Interpreting results of coronary computed tomography angiography-derived fractional flow reserve in clinical practice

The application of computational fluid dynamics to coronary computed tomography angiography allows Fractional Flow Reserve (FFR) to be calculated non-invasively (FFRCT), enabling computation of FFR from coronary computed tomography angiography acquired at rest both for individual lesions as well as along the entire course of a coronary artery. FFRCT, validated in a number of accuracy studies and a large clinical utility trial, is beginning to penetrate clinical practice. Importantly, while accuracy trials compared FFRCT to invasively measured FFR at a single point in the coronary tree, clinical reports of FFRCT provide information regarding a patients entire coronary vasculature. Specifically, in distal coronary segments, calculated FFRCT values may be low and below 0.80 even in the absence of localized stenoses within the course of the artery. As a result, the reporting physician needs to understand how to interpret the findings in a clinically useful and thoughtful fashion. This review provides a brief overview of the background of both invasively measured and computationally derived FFR, explains changes in FFR along the course of normal coronary arteries and those affected by coronary atherosclerosis, and outlines the relevance of measurement location when interpreting and reporting FFR and FFRCT results.

Dependency of prescribed CT dose on table height, patient size, and localizer acquisition for one clinical MDCT

PURPOSE The purpose of this study was to quantify the effect that table height, patient size, and localizer acquisition order may have on AEC prescribed dose. METHOD AND MATERIALS Three phantoms were used for this study: the Mercury Phantom, acrylic sheets, and an anthropomorphic phantom. A lateral (LAT) and a posterior-anterior (PA) localizer was acquired for each phantom at different table heights on a MDCT scanner (GE Discovery CT750 HD). AEC scan acquisitions were prescribed for each combination of phantom, localizer orientation, and table height ±4 cm with the center position; the displayed CTDIvol was recorded. Based on the institutional dose monitoring program, the relationship between change in CTDIvol and change in table height were studied for LAT and AP localizers for clinical exams. RESULTS For all phantom scans based on the PA localizer, the percent change in ranged between -18% and 42% for table heights 4 cm below and above proper centering; while for the LAT localizer, the percent change in CTDIvol from ideal were no greater than 12% different for ±4 cm differences in table height. Change in CTDIvol and change in table height displayed a strong linear relationship for AP localizer exams (P = 0.002), and weak correlation for LAT localizer exams (P = 0.12). CONCLUSIONS Since uncertainty in vertical patient positioning is inherently greater than lateral positioning, the LAT localizer should be utilized to precisely and reproducibly deliver the intended amount of radiation prescribed by CT protocols.

Coronary artery calcium: A technical argument for a new scoring method

Coronary artery calcium (CAC) is a strong predictor for future cardiovascular events. Traditionally CAC has been quantified using the Agatston score, which was developed in the late 1980s for electron beam tomography (EBT). While EBT has been completely replaced by modern multiple-detector row CT technology, the traditional CAC scoring method by Agatston remains in use, although the literature indicates suboptimal reproducibility and subjects being incorrectly classified. The traditional Agatston scoring method counteracts the technical advances of CT technology, and prevents the use of thinner sections, obtained at lower tube voltage and overall decreased radiation exposure that has become available to other CT applications. Moreover, recent studies have shown that not only the total amount of CAC, but also its density and distribution in the coronary arterial tree may be of prognostic value. Acquisition and reconstruction techniques thus need to be adapted for modern CT technology and optimized for CAC quantification. In this review we describe the technical limitations of the Agatston score followed by our suggestions for developing a new and more robust CAC quantification method.

Cardiovascular Imaging With 18 F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Patients With Fibroinflammatory Disorders

Fibroinflammatory disorders are rare disorders characterized by chronic inflammation in combination with fibrosis that affect multiple organs. Among the fibroinflammatory disorders, 2 present with specific cardiovascular involvement, the immunoglobulin G4–related disease, which presents with

Left atrial appendage to great cardiac vein fistula complicating watchman left atrial appendage closure

A 67-year-old man with persistent atrial fibrillation, recurrent gastrointestinal bleeding, and recent percutaneous coronary intervention presented for evaluation of left atrial appendage (LAA) closure. Pre-procedural TEE revealed an EF of >55%, an intact interatrial septum and no evidence of LAA thrombus. Pre-procedural CT revealed a vessel connecting the anterior tip of the LAA to the great cardiac vein ( Panel 1 ). Intraprocedural LAA angiography confirmed the presence of …