Robert C. Gilkeson

Coronary Artery Fistulas: CT Findings

Coronary artery fistulas are anomalous terminations of the coronary arteries. Most often, these fistulas are incidentally identified in the adult and pediatric populations. Many patients are asymptomatic; however, an awareness of these fistulas is important because they have been associated with various clinical features, including chest pain or heart failure in young patients. Correct diagnosis of coronary artery fistulas is important, and early surgical correction is indicated because of the high prevalence of late symptoms and complications. Traditionally, conventional angiography has been used for the diagnosis of coronary anomalies. With more frequent use of 64-row multi-detector computed tomography (CT) in chest and cardiac imaging, the number of incidentally found coronary artery fistulas has been increasing. CT angiography and conventional angiography can have additive value in diagnosis of this cardiac anomaly. In every CT study of the heart, special attention should be paid to the courses and terminations of the coronary arteries to detect these potentially fatal anomalies.

Soluble CD14 is independently associated with coronary calcification and extent of subclinical vascular disease in treated HIV infection

Objective:To use multimodality imaging to explore the relationship of biomarkers of inflammation, T-cell activation and monocyte activation with coronary calcification and subclinical vascular disease in a population of HIV-infected patients on antiretroviral therapy (ART). Design:Cross-sectional. Methods:A panel of soluble and cellular biomarkers of inflammation and immune activation was measured in 147 HIV-infected adults on ART with HIV RNA less than 1000 copies/ml and low-density lipoprotein cholesterol (LDL-C) 130 mg/dl or less. We examined the relationship of biomarkers to coronary calcium (CAC) score and multiple ultrasound measures of subclinical vascular disease. Results:Overall, median (interquartile range, IQR) age was 46 (40–53) years; three-quarters of participants were male and two-thirds African-American. Median 10-year Framingham risk score was 6%. Participants with CAC more than 0 were older, less likely to be African-American and had higher current and lower nadir CD4+ T-cell counts. Most biomarkers were similar between those with and without CAC; however, soluble CD14 was independently associated with CAC after adjustment for traditional risk factors. Among those with a CAC score of zero, T-cell activation and systemic inflammation correlated with carotid intima–media thickness and brachial hyperemic velocity, respectively. Compared with normal participants and those with CAC only, participants with increasing degrees of subclinical vascular disease had higher levels of sCD14, hs-CRP and fibrinogen (all P < 0.05). Conclusion:Soluble CD14 is independently associated with coronary artery calcification, and, among those with detectable calcium, predicts the extent of subclinical disease in other vascular beds. Future studies should investigate the utility of multimodality imaging to characterize vascular disease phenotypes in this population.

MDCT evaluation of aortic valvular disease

OBJECTIVE This essay depicts recent advances of MDCT in the evaluation of aortic valvular disease. CONCLUSION Aortic valvular disease can be assessed with current MDCT technology. The improved imaging characteristics of MDCT have significantly decreased artifacts traditionally seen with prosthetic aortic valves and enabled excellent visualization of valve function. Advances in ECG-gated MDCT technology offer the opportunity to evaluate a variety of aortic valvular abnormalities.

CT evaluation of congenital heart disease in adults.

OBJECTIVE The purpose of this article is to describe the spectrum of imaging findings of congenital heart disease in adults. CONCLUSION Continued advances in CT have facilitated evaluation of two important patient populations: adults with surgically palliated congenital heart disease and adults with previously undiagnosed congenital heart disease.

Evaluation of Right Ventricular Fibrosis in Adult Congenital Heart Disease Using Gadolinium‐enhanced Magnetic Resonance Imaging: Initial Experience in Patients with Right Ventricular Loading Conditions

OBJECTIVE Gadolinium-enhanced cardiac magnetic resonance imaging has been used to show myocardial fibrosis, a finding that appears as late gadolinium enhancement. Its role in the evaluation of right ventricular fibrosis in congenital heart disease is unclear. The purpose of this study was to demonstrate late gadolinium enhancement of the right ventricle in adult and adolescent congenital heart disease and to investigate the relationship between this enhancement and clinical and pathophysiological data. DESIGN In total, 24 patients, 16 patients with congenital heart disease and right ventricular loading conditions and 8 controls, underwent gadolinium-enhanced viability imaging. Diagnoses varied and included repaired, palliated, and unrepaired lesions. The presence and extent of right ventricular late gadolinium enhancement was compared with patient clinical and hemodynamic data. Exact Wilcoxon tests, Fishers exact tests, and Spearmans rank correlation were used to compare variables. RESULTS Nine of 16 patients (56%) were found to have right ventricular late gadolinium enhancement, ranging from 5% to 80% of right ventricular myocardium affected (mean 36.1%, SD 29.7). The combination of right ventricular systolic pressure >or=98 mm Hg and systemic oxygen saturation <or=93% strongly suggested the presence of right ventricular late gadolinium enhancement (positive predictive value 100%), but no single variable or combination of variables could reliably predict its absence (negative predictive values <or=75%). Extent of right ventricular late gadolinium enhancement did not correlate with degree of either hypoxia or right ventricular hypertension. CONCLUSIONS Gadolinium-enhanced cardiac magnetic resonance demonstrates right ventricular late gadolinium enhancement in some patients with congenital heart disease and right ventricular loading conditions. Clinical variables were associated with the presence of fibrosis but did not reliably predict severity. Myocardial preservation is likely a multifactorial process that may affect the right and left ventricles differently.

Applications of Time-Resolved MR Angiography

OBJECTIVE The purpose of this essay is to describe the basic principles behind contrast-enhanced time-resolved MR angiography (MRA) performed with the time-resolved imaging with stochastic trajectories technique and to show examples of the versatile applications of this technique in the evaluation of pathologic conditions throughout the body. CONCLUSION Time-resolved MR angiography is a versatile technique for vascular imaging throughout the body. It can be used to answer a variety of clinical questions; to acquire diagnostically useful information, even about complicated vascular lesions; and to overcome many of the limitations of bolus-chase contrast-enhanced MR angiography. The technique is particularly useful when the arterial arrival time is uncertain, the patient is freely breathing, or contrast dynamics are critical to a diagnosis.

Comparison of ECG‐Gated Rectilinear vs. Real‐Time Radial K‐Space Sampling Schemes in Cine True‐FISP Cardiac MRI

PURPOSE To compare three k-space sampling schemes in cine True-FISP cardiac magnetic resonance imaging and to evaluate changes in calculated quantitative functional cardiac parameters as a function of underlying k-space sampling techniques. MATERIAL AND METHODS Using a 1.5 T MR imaging system (Magnetom Sonata, Siemens Medical Solutions, Erlangen, Germany), three k-space data-sampling schemes: rectilinear (2.96 ms/1.58 ms/70 degrees /12 s TR/TE/FA/AcquisitionTime), and two radial k-space acquisitions, with filtered back-projection (RADIAL) (2.45 ms/1.25 ms/ 50 degrees /3.3 s TR/TE/FA/AT), and steady-state projection imaging with dynamic echotrain readout (SPIDER) (3.39 ms/1.62 ms/55 degrees /1.8 s TR/TE/FA/AT) of a True-FISP sequence were applied in 10 healthy volunteers. Long- and short-axis breath-hold series were acquired and signal-to-noise ratios (SNR) for blood and myocardium were determined, as was contrast-to-noise ratios (CNR). Quantitative cardiac functional analysis included: determination of end-systolic/end-diastolic volumes, ejection fraction, and left ventricular mass. Functional analysis was performed by two independent readers three times for each volunteer and k-space sampling strategy. Statistical analysis evaluated the accuracy of the measurements obtained from each of the three sampling techniques and the intra- and interobserver reliability. RESULTS Intraobserver and interobserver reliability measures of functional data were homogeneous without statistically significant differences. Intraobserver correlation coefficients ranged from 0.94-0.99; interobserver correlation coefficients ranged from 0.97-0.99. Direct comparison of SPIDER- and RADIAL-sampled True-FISP sequences showed no statistically significant differences in measured functional parameters with interstudy correlation coefficients from 0.88-0.98. RADIAL and SPIDER images had better temporal resolution and were qualitatively judged to provide superior wall/blood border definition. Statistically significant differences were identified in each volumetric functional parameter when results from the rectilinear sampling acquisitions were compared with either radial or SPIDER sampling techniques. RADIAL and SPIDER results were consistently higher than volumetric measures obtained from the rectilinear data set. CONCLUSION Employing faster sampling schemes led to enhanced signal homogeneity while maintaining the necessary CNR for estimation of functional cardiac parameters. Enhanced signal homogeneity and maintained CNR will most likely improve the accuracy of the cardiac functional parameter determination.

Rosuvastatin slows progression of subclinical atherosclerosis in patients with treated Hiv infection

Objective:To determine the effect of statins on the progression of subclinical atherosclerosis in a population of HIV-infected adults on antiretroviral therapy. Design:Double-blind, randomized clinical trial. Methods:Stopping Atherosclerosis and Treating Unhealthy Bone with RosuvastatiN in HIV infection was a 96-week double-blind, randomized clinical trial of 10 mg daily rosuvastatin (n = 72) vs. placebo (n = 75) in a population of HIV-infected subjects on stable antiretroviral therapy with LDL-cholesterol 130 mg/dl or less (⩽3.36 mmol/l) and evidence of heightened T-cell activation (CD8+CD38+HLA-DR+ ≥19%) or increased inflammation [high sensitivity C-reactive protein ≥2 mg/l (≥19 mmol/l)]. Change in common carotid artery intima–media thickness (IMT) (CCA-IMT) was the primary outcome. Secondary outcomes were changes in LDL and coronary artery calcium. Results:Median (Q1, Q3) age was 46 (40, 53) years; 78% were man and 68% African-American; 49% were on a protease inhibitor. Mean (95% confidence interval) change in LDL was −21 (−27 to −15) mg/dl [−0.54 (−0.70 to −0.39) mmol/l] in the rosuvastatin arm. In a multivariable linear mixed-effects model, assignment to statin was associated with 0.019 mm (95% confidence interval: 0.002–0.037 mm) less progression of CCA-IMT over 96 weeks. We did not find substantial effect modification by level of inflammation or immune activation biomarkers, except for a borderline statistically significant interaction for soluble vascular cell adhesion molecule (P = 0.065). There was no difference in coronary artery calcium change (P = 0.61). Conclusion:Rosuvastatin effectively lowers LDL and appears to substantially slow progression of CCA-IMT in patients with treated HIV infection. Future study is needed to determine whether subjects with higher levels of inflammation or immune activation derive greater cardiovascular benefit from statin therapy.

Computed tomography in the evaluation of vascular rings and slings.

AbstractVascular rings are congenital abnormalities of the aortic arch-derived vascular and ligamentous structures, which encircle the trachea and oesophagus to varying degrees, resulting in respiratory or feeding difficulties in children. A sling is an abnormality of the pulmonary arterial system resulting in airway compression. Although several imaging examinations are available for the evaluation of these anomalies, computed tomography (CT) has become the preferred test because of rapid acquisitions, making it feasible to perform the study without sedation or general anaesthesia. Furthermore, CT provides excellent spatial and temporal resolution, a wide field of view, multiplanar reconstruction capabilities and simultaneous evaluation of the airway. In this review, the current role and technique of CT in the evaluation of vascular rings are discussed. A brief discussion of the embryology of the aorta and branch vessels is followed by discussion and illustration of common and some uncommon vascular rings along with critical information required by surgeons. Teaching Points • Computed tomography is valuable in the evaluation of vascular rings.• Due to variable clinical and imaging presentations, diagnosis of vascular rings is often challenging.• Laterality of the arch is critical in surgical management.

Comparing multislice electrocardiogram-gated spiral computerized tomography and transesophageal echocardiography in evaluating aortic atheroma in patients with acute ischemic stroke.

OBJECTIVE The aim of this study was to compare transesophageal echocardiography (TEE) and cardiac-gated computerized tomography (CGCT) in detecting aortic atherosclerosis (AA). BACKGROUND There is evidence that AA can be a source of embolic material causing ischemic stroke. TEE is a well-established tool for detecting cardiac sources of emboli in patients with stroke, but it has distinct limitations in the detection of AA. METHOD This was a prospective study of patients admitted with the diagnosis of ischemic stroke between February and November of 2000. Among this cohort are patients who underwent both TEE and CGCT for the evaluation of stroke cause. The CGCT studies were retrieved and interpreted by a radiologist with special expertise in chest tomography, and TEE studies were read by an echocardiographer with special expertise in reading and performing TEE. The interpreters were unaware of the results obtained by the other. The AA was estimated by measuring atheroma thickness in millimeters. The relations between the two tests were analyzed graphically using Bland-Altman, and Pollock plots. Results from Pearson (r), Spearman (r(s)), and intraclass correlation tests were also estimated. RESULTS The aortic atheroma thickness in millimeters was compared between CGCT and TEE in 32 patients, who underwent both studies. The intraclass correlation was 0.93, with high correlation (r = 082, r(s) = 0.83). CGCT detected smaller AA more often, and provided more information about the shape of atheromatous plaques. CONCLUSION CGCT is similar to TEE in detecting AA. CGCT may detect smaller atheromas and be better in defining atheroma morphology.