William Stanford

Multidetector CT of the thoracic aorta

Recent advancement of MDCT provides high-resolution axial images with optimal contrast enhancement and 3D reformatted images of the thoracic aorta. MDCT is now playing a dominant and critical role in the evaluation of thoracic aortic disease. This article will focus on procedural considerations of MDCT: acquisition parameters, contrast injection and post-processing techniques and imaging findings of thoracic aortic diseases including, aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer, aneurysm, and traumatic injury.

CT evaluation of left atrial pulmonary venous anatomy

Abstract.Multidetector CT (MDCT) visualization of the left atrial pulmonary venous anatomy is becoming increasingly requested prior to radiofrequencey catheter ablation (RFCA) procedures for refractory cardiac arrhythmias. MDCT imaging can define left atrial anatomy including atrial size and venous attachments as well identify complications such as stenoses, dissections or perforations. Proper understanding enables the cardiac imager to be knowledgeable so as to obtain the specific information needed for the interventional cardiologist. This paper reviews the left atrial venous anatomy, the clinical aspects of refractory atrial fibrillation, MDCT imaging protocols, procedural aspects of the ablation, and complications should they arise.

Accurate preoperative diagnosis of pericardial constriction using cine computed tomography

OBJECTIVESnThe purpose of this study was to determine the accuracy of cine computed tomography in the diagnosis of constrictive pericarditis.nnnBACKGROUNDnConstrictive pericarditis is characterized by abnormalities of both cardiac structure and function. Accurate diagnosis requires detection of both a thickened pericardium and abnormal ventricular diastolic filling. At present, no one diagnostic technique has demonstrated sufficient accuracy in this setting. Cine computed tomography is a relatively new cardiac imaging mode with very high time and spatial resolution that has the potential to accurately diagnose constrictive pericarditis.nnnMETHODSnTwelve consecutive patients were retrospectively identified who had catheterization findings suggestive of constrictive physiology, had undergone a cine computed tomographic examination and had pathologic data that delineated the status of the pericardium. Group 1 (with constrictive pericarditis; n = 5) had surgical confirmation of thickened pericardium and improved clinically after pericardiectomy. Group 2 (no constrictive pericarditis; n = 7) had cardiomyopathy with normal pericardium. Seven normal volunteers (Group 3) were also studied. Cine computed tomograms were obtained for the entire heart (8-mm slices, 17 frames/s, nonionic contrast medium). Pericardial thickness was measured at 10 degrees intervals at three ventricular levels in each subject. The rapidity of diastolic filling was assessed by calculating the percent filling fraction in early diastole.nnnRESULTSnPericardial thickness was 10 +/- 2 mm (mean +/- SD) in Group 1, 2 +/- 1 mm in Group 2 and 1 +/- 1 mm in Group 3 (p < 0.05, constrictive pericarditis vs. no constrictive pericarditis). Left ventricular filling fraction was 83 +/- 6% in Group 1, 62 +/- 9% in Group 2 and 44 +/- 5% in Group 3. Right ventricular filling fraction was 93 +/- 5% in Group 1, 62 +/- 14% in Group 2 and 35 +/- 6% in Group 3 (p < 0.05, Group 1 vs. Groups 2 and 3). Both indexes provided a clear-cut distinction between patients with and without constriction.nnnCONCLUSIONSnCine computed tomography simultaneously provides both anatomic and physiologic data that allow accurate preoperative diagnosis of pericardial constriction.

Preablation assessment for the left atrium: comparison of ECG-gated cardiac CT with echocardiography.

RATIONALE AND OBJECTIVESnEvaluate the role of two-dimensional echocardiography and electrocardiographically (ECG)-gated contrast-enhanced multislice computed tomographic (MSCT) cardiac imaging to assess cardiac anatomy, specifically pulmonary venous anatomy and left atrial thrombus, in a selected group of patients before catheter-based atrial fibrillation ablation.nnnMATERIALS AND METHODSnLeft atrial anatomy and associated findings in 34 consecutive patients scheduled for electrophysiologic testing who underwent both echocardiography and ECG-gated 16-slice MSCT cardiac imaging were retrospectively compared. Results from two-dimensional transthoracic echocardiography (TTE), cardiac MSCT, electrophysiologic study (EPS), and transesophageal echocardiography (TEE) (when performed) were taken from the official medical record without prior knowledge of this study when interpretation was rendered for clinical use. Electronic record review included: presence of left atrial thrombus (defined as constant filling defect on at least two echocardiographic views or filling defect on computed tomography) and location, pulmonary venous anatomy, and other cardiac, mediastinal, or pulmonary abnormalities.nnnRESULTSnLeft atrial thrombus was identified by cardiac MSCT alone in five patients (15%). Pulmonary venous variants were identified with cardiac MSCT in two patients (6%). Both MSCT and echocardiography were normal in 17 subjects (79%). Echocardiography was better at identifying associated valvular abnormalities that were seen in 10 patients (29%). Cardiac MSCT angiography alone identified other cardiac and noncardiac abnormalities, including suspicious pulmonary malignancy, mediastinal adenopathy, and coronary stenosis in 15 patients (44%).nnnCONCLUSIONSnEchocardiography and cardiac MSCT angiography often provide complimentary findings during the preprocedural evaluation for patients with atrial fibrillation requiring ablation. Cardiac MSCT may provide significant additional information about the left atrium, mediastinum, coronary circulation, and visualized lung fields. Based on this study, we would advise that patients considered for radiofrequency ablation for uncontrolled right atrial fibrillation have both echocardiography and ECG-gated contrast-enhanced cardiac MSCT performed as part of the preprocedure evaluation.

The role of coronary artery calcifications in coronary artery disease.

Calcification within the wall of a coronary artery is a recognized marker of atherosclerosis. Imaging modalities used in detection of coronary calcification are the chest film, fluoroscopy, and conventional, electron beam and helical CT. The faster electron beam CT (EBT) and helical CT (HCT) scanners are especially sensitive in detecting coronary artery calcification. Thus, these imaging modalities are increasingly being used in detecting pre-clinical coronary artery disease.

Alternates to EBCT for coronary calcium.

HCT and EBT imaging of soft plaque and the use of these modalities in CT angiographic applications are important in the non-calcified plaque assessment of coronary artery disease and in the follow-up of treatment.

Clinical Applications of Ultrafast Computed Tomography

For over two decades, three imaging technologies (echocardiography, contrast ventriculography, and conventional nuclear techniques utilizing gamma-emitting radioisotopes) have played a dominant role in assessing the structure and function of the heart in patients with cardiovascular diseases. A t present, in the United States, it is likely that these three techniques fulfill the majority of the imaging needs of the practicing cardiologist. In the past several years, five new cardiac imaging techniques have emerged and are beginning to be used in the assessment of cardiac structure, function, and metabolism in patients with cardiovascular diseases. These techniques include positron emission tomography, singlephoton emission computed tomography, nuclear magnetic resonance, digital subtraction angiography, and ultrafast computed tomography. All of these newer techniques have impressive capabilities that are in some cases unique and unmatched by present, standard imaging methods. They are likely to come into frequent use during the next 5 or 10 years, and, quite possibly, will dominate cardiovascular imaging. This review will describe current studies that relate to potential clinical applications of one of these five new imaging modalities-ultrafast computed tomography.

Esophagotracheal Fistula From a Pharyngoesophageal Diverticulum

Pharyngo-esophageal (Zenkers) diverticula are rarely associated with tracheal fistulas; however, the diagnosis should be suspected in the diverticulum patient who presents with spasms of coughing while eating since, if found, it changes the surgical management. The roentgenographic findings, diagnostic modalities, and surgical management of such a patient are herein presented.