Jeffrey C. Hellinger

Computed tomography angiography: state-of-the-art imaging using multidetector-row technology.

Multidetector-row computed tomography (MDCT) is an essential diagnostic modality for many clinical algorithms. This is particularly true with regard to the evaluation of cardiovascular disease. As a result of increased image acquisition speed, improved spatial resolution, and greater scan volume, MDCT angiography (computed tomography angiography [CTA]) has become an excellent noninvasive imaging technique, replacing intra-arterial digital subtraction angiography for most vascular territories. The clinical success of CTA depends on precise synchronization of image acquisition with optimal vascular enhancement. As technology continuously evolves, however, this task can be challenging. It remains important to have a fundamental knowledge of the principles behind technical parameters and contrast medium administration. This article reviews these essential principles, followed by an overview of current clinical applications.

Cardiac CINE imaging with IDEAL water-fat separation and steady-state free precession.

to decompose multicoil CINE steady‐state free precession (SSFP) cardiac images acquired at short echo time (TE) increments into separate water and fat images, using an iterative least‐squares “Dixon” (IDEAL) method.

Current Imaging of Prenatally Diagnosed Congenital Lung Lesions

Congenital lung lesions refer to a spectrum of pulmonary developmental anomalies including, but not limited to, bronchial atresia, congenital pulmonary airway malformation (formerly known as congenital cystic adenomatoid malformation) and bronchopulmonary sequestration. These anomalies comprise about 90% of the anomalies seen in clinical practice. The advent of prenatal sonography and, more recently, fetal magnetic resonance imaging has changed our understanding and practice in the evaluation of congenital lung lesions. Postnatal imaging using low-dose computed tomography angiography (CTA) is extremely useful as it may provide information essential for differential diagnosis by allowing multiplanar reconstructions of the airway, lung parenchyma, and vasculature. The use of iodine in CTA permits the application of low-dose radiation protocols in these young patients. The purpose of this article is to emphasize the technical factors that may optimize low-dose CTA evaluation of these lesions. We also provide a description of prenatal imaging findings and helpful diagnostic clues that may be useful for the characterization of the most commonly encountered prenatally diagnosed pulmonary developmental anomalies.

Cumulative exposure to medical radiation for children requiring surgery for congenital heart disease.

OBJECTIVE To describe cumulative radiation exposure in a large single-center cohort of children with congenital heart disease (CHD) and identify risk factors for greater exposure. STUDY DESIGN A detailed medical radiation exposure history was collected retrospectively for patients aged <18 years who underwent surgery for CHD between January 1, 2001, and July 22, 2009. Cumulative per patient exposure was quantified as the effective dose in millisieverts (mSv) and annualized (mSv/year). RESULTS A total of 4132 patients were subjected to 134,715 radiation examinations at a median follow-up of 4.3 years (range, 0-8.6 years). Exposure clustered around the time of surgery. The median exposure was 14 radiologic tests (the majority of which were plain film radiographs) at an effective dose of 0.96 mSv (the majority of which was from cardiac catheterization), although this distribution had a very wide range. Almost three-quarters (73.7%) were exposed to <3 mSv/year, and 5.3% were exposed to >20 mSv/year. Neonates, children with genetic syndromes, and children requiring surgery for cardiomyopathy, pulmonary valve, single ventricle, or tricuspid valve diseases were more likely to have higher exposure levels, and those requiring surgery for aortic arch anomalies or atrioventricular septal defects were more likely to have lower levels. CONCLUSION Children with CHD requiring surgery are exposed to numerous medical forms of ionizing radiation. Although the majority of patients receive <3 mSv/year, there are identifiable risk factors for higher exposure levels. This may have important health implications as these patients age.

Identification, imaging, functional assessment and management of congenital coronary arterial abnormalities in children

The coronary arteries, the vessels through which both substrate and oxygen are provided to the cardiac muscle, normally arise from paired stems, right and left, each arising from a separate and distinct sinus of the aortic valve. The right coronary artery runs through the right atrioventricular groove, terminating in the majority of instances in the inferior interventricular groove. The main stem of the left coronary artery bifurcates into the anterior descending, or interventricular, and the circumflex branches. Origin of the anterior descending and circumflex arteries from separate orifices from the left sinus of Valsalva occurs in about 1% of the population, while it is also frequent to find the infundibular artery arising as a separate branch from the right sinus of Valsalva. Anomalies of the coronary arteries can result from rudimentary persistence of an embryologic coronary arterial structure, failure of normal development or normal atrophy as part of development, or misplacement of connection of a an otherwise normal coronary artery. Anomalies, therefore, can be summarized in terms of abnormal origin or course, abnormal number of coronary arteries, lack of patency of the orifice of coronary artery, or abnormal connections of the arteries. Anomalous origin of the left coronary artery from the pulmonary trunk occurs with an incidence of approximately 1 in 300,000 children. The degree of left ventricular dysfunction produced likely relates to the development of collateral vessels that arise from the right coronary artery, and provide flow into the left system. Anomalous origin of either the right or the left coronary artery from the opposite sinus of Valsalva can be relatively innocuous, but if the anomalous artery takes an interarterial course between the pulmonary trunk and the aorta, this can underlie sudden death, almost invariably during or immediately following strenuous exercise or competitive sporting events. Distal anomalies of the coronary arteries most commonly involve abnormal connections, or fistulas, between the right or left coronary arterial systems and a chamber or vessel. We discuss the current techniques available for imaging these various lesions, along with their functional assessment, concluding with a summary of current strategies for management.

Portosystemic pressure gradient during transjugular intrahepatic portosystemic shunt with Viatorr stent graft: What is the critical low threshold to avoid medically uncontrolled low pressure gradient related complications?

Background:  Inappropriately decreased portosystemic pressure gradient (PSG) during transjugular intrahepatic portosystemic shunt (TIPS) can cause fatal complications but the critical low threshold of PSG is still not clear. The aim of the present study was to evaluate the critical low threshold of PSG during TIPS.

A prospective observational study of IVC filters in pediatric patients

The use of inferior vena cava (IVC) filters to prevent pulmonary embolism (PE) has increased with the advent of retrievable filters (Crowther: Am J Med 120: S13–S17, 2007). Both permanent and retrievable filters have been used in the pediatric population, though reports describing such patients and their outcomes are limited.

Congenital thoracic vascular anomalies: evaluation with state-of-the-art MR imaging and MDCT.

Congenital thoracic vascular anomalies include embryologic developmental disorders of the thoracic aorta, aortic arch branch arteries, pulmonary arteries, thoracic systemic veins, and pulmonary veins. Diagnostic evaluation of these anomalies in pediatric patients has evolved with innovations in diagnostic imaging technology. State-of-the-art magnetic resonance (MR) imaging, MR angiography multidetector-row computed tomographic (MDCT) angiography, and advanced postprocessing visualization techniques offer accurate and reliable high-resolution two-dimensional and three-dimensional noninvasive anatomic displays for interpretation and clinical management of congenital thoracic vascular anomalies. This article reviews vascular MR imaging, MR angiography, MDCT angiography, and advanced visualization techniques and applications for the assessment of congenital thoracic vascular anomalies, emphasizing clinical embryology and the characteristic imaging findings.

Peri-Infarct Ischemia Determined by Cardiovascular Magnetic Resonance Evaluation of Myocardial Viability and Stress Perfusion Predicts Future Cardiovascular Events in Patients with Severe Ischemic Cardiomyopathy

BACKGROUND We assessed whether cardiovascular magnetic resonance imaging (CMR) of peri-infarct ischemia provides prognostic information in severe ischemic cardiomyopathy (ICM) patients referred for revascularization. METHODS Twenty-one patients with severe ICM were recruited prospectively for combined stress adenosine perfusion, late gadolinium enhancement, and rest perfusion studies. The patients were followed for in-hospital and post-discharge cardiovascular events. RESULTS During 12+/- 9.8 months follow-up, 67% of the patients with peri-infarct ischemia and 13% of the patients without peri-infarct ischemia had cardiovascular events (p = 0.03). CONCLUSION. In severe ICM patients, the presence of peri-infarct ischemia was associated with a higher incidence of cardiovascular events.

The role of CT angiography in the evaluation of pediatric renovascular hypertension

Historically, the evaluation of renovascular hypertension has been accomplished by US, renal scintigraphy and digital subtraction angiography. Based on its high accuracy reported in adults renal CT angiography (CTA) with pediatric-appropriate low radiation dose techniques has become an important tool in the workup of renovascular hypertension in children. Renal CTA has several advantages over more conventional imaging modalities, including rapid and non-invasive acquisition, high resolution and easy reproducibility. Additionally, in our experience high-quality renal CTA can be performed using low-dose radiation exposures and can be acquired without sedation in most instances. This article illustrates by examples the usefulness of renal CTA for diagnosis of childhood renovascular hypertension and provides an overview of renal CTA findings in the most common childhood renovascular diseases.