Comparison of transesophageal echocardiography versus computed tomography for detection of left atrial appendage filling defect (thrombus).

Patients with atrial fibrillation, who are referred for radiofrequency pulmonary vein antral isolation, frequently undergo transesophageal echocardiography (TEE) to detect and/or exclude left atrial or left atrial appendage (LAA) thrombus and cardiac computed tomographic angiography (CCTA) to define and/or evaluate left atrial and pulmonary venous anatomy. Previous studies have reported CCTA to have high sensitivity and negative predictive value (NPV) for detecting thrombus in the LAA. Previous studies determining an optimal LAA/ascending aorta (AA) Hounsfield unit (HU) density ratio for detection of LAA thrombus have been small, with limited numbers of thrombi. We thus sought to determine both the optimal cutoff for LAA HU density and LAA/AA HU density ratio in detecting LAA thrombus compared with TEE in a multicenter population. We included 84 patients who had undergone CCTA and TEE. LAA was evaluated by 64-row CCTA qualitatively (visual filling defect) and quantitatively (measurement of LAA HU density and LAA/AA HU density ratio), using a 1-cm area of interest in the same axial plane. Results were compared with TEE visualization of thrombus or spontaneous echo contrast. Qualitative identification of thrombus in LAA by CCTA compared with TEE detection of thrombus had a sensitivity of 100%, a specificity of 77.9%, a positive predictive value (PPV) of 51.6%, an NPV of 100%, and a total accuracy of 82.1%. The optimal LAA HU density cutoff for thrombus detection was 119 with a sensitivity of 88%, a specificity of 86%, PPV 56%, and an area under the curve of 0.923 (p = 0.0004). The optimal LAA/aorta HU ratio was 0.242 with a sensitivity of 87%, a specificity of 88%, a PPV of 64%, and an area under the curve of 0.921 (p = 0.0011). There is no significant difference (p = 0.72) between both areas under the curve, and both measurements improved the specificity and PPV compared with qualitative measures. Multidetector computed tomography is an imaging technique that can exclude LAA thrombus with very high NPV. Quantitative measurement of LAA HU density (cutoff 119) or LAA/aorta HU density ratio (cutoff 0.242) improves accuracy of positively detecting LAA thrombus. This technique is especially useful when delayed scanning is not performed and LAA is found incidentally after the patient scanning is complete.

Use of cardiovascular computed tomography in the diagnosis and management of coarctation of the aorta.

Coarctation of the aorta is a common malformation accounting for 5% to 8% of all congenital heart defects. Although echocardiography and magnetic resonance imaging are most frequently used in the diagnosis and management of coarctation of the aorta, the role of multidetector computed tomography in congenital heart defects has been expanding and its use has been increasing over the last few years. Multidetector computed tomography with its high spatial and temporal resolution, multiplanar reconstruction capabilities, and wide field of view is an excellent tool for the detection and characterization of coarctation of the aorta, and the identification of associated anomalies of the heart and pulmonary vasculature. It is particularly useful and indicated in patients with contraindications for cardiac magnetic resonance (eg, patients with aortic or coronary artery stents, pacemakers or implantable cardioverter defibrillators, and mechanical heart valves). Knowledge of the cardiac computed tomography appearance of coarctation of the aorta and associated abnormalities is critical for accurate diagnosis and management, which includes providing information to plan surgical or percutaneous therapy. We present various forms of coarctation of the aorta on cardiac computed tomography.

Single coronary artery syndrome: cardiac computed tomography angiography as a leading imaging modality.

Single coronary artery syndrome is usually an asymptomatic condition in most patients; thus most patients are diagnosed when noninvasive imaging (cardiac computed tomography angiography, cardiac magnetic resonance) or invasive coronary angiography is done for evaluation for other cardiac conditions. With advances using cardiovascular imaging in the evaluation and management of single coronary artery syndrome; Cardiac Computed Tomography Angiography (CCTA) has emerged as a very essential and leading imaging modality. CCTA has the best resolution (spatial and temporal) among the imaging modalities available for analyzing the cardiovascular system for the diagnosis and management of single coronary artery syndrome. We are presenting cases of patients with single coronary artery syndrome with 3 different courses (anterior, septal, inter-arterial), illustrating how CCTA gives a detailed anatomic/structural evaluation of the origin and course of the coronary arteries, and other cardiac structures. Thus in patients diagnosed with single coronary artery syndrome, CCTA can provide vital information on the not only the course, but the associated narrowing of coronary vessels.

Coronary artery aneurysms as seen on multidetector computed tomography angiography.

Coronary artery aneurysms (CAA) are present in 1.4-5.3% of the population (Nichols, Lagana, Parwani. Arch Pathol Lab Med 2008; 132:823-828). While angiography remains the gold standard for evaluating CAAs, multidetector computed tomography angiography (MDCTA) is an emerging way of assessing CAAs (Pahlavan and Niroomand. Clin Cardiol 2006;29:439-443). With the increasing clinical utilization of MDCTA, CAAs are often initially diagnosed using this method. Since MDCTA is used largely in lower risk and asymptomatic patients, understanding the etiology and treatment is paramount for clinicians reading these studies.