Cardiac Imaging Update

Clinical and technical considerations for stress myocardial perfusion imaging with multidetector computed tomography.

J Cardiovasc Comput Tomogr. 2009 November – December;3S2:S74-S80

Authors: Bragadeesh TK, Shapiro MD

Cardiovascular compute tomography (CT) is now a robust tool for the evaluation of coronary artery atherosclerosis and stenosis. A number of single-center studies, and now multicenter trials, have shown that the diagnostic accuracy of this tool compares favorably with the reference standard of conventional coronary angiography. Of course, CT angiography does not allow for the assessment of the functional significance of a given coronary lesion. However, recent reports have shown that myocardial perfusion imaging is possible with CT, opening up the possibility of providing a comprehensive evaluation of both coronary anatomy and physiology with one examination. This article reviews the principles, technical considerations, and the potential of stress myocardial perfusion imaging with CT.

PMID: 20129520 [PubMed - as supplied by publisher]

More here

Methods of plaque quantification and characterization by cardiac computed tomography.

J Cardiovasc Comput Tomogr. 2009 November – December;3S2:S91-S98

Authors: Maurovich-Horvat P, Ferencik M, Bamberg F, Hoffmann U

The pathologic evolution of coronary artery atherosclerosis occurs slowly over decades, which may provide an opportunity for diagnostic imaging to identify patients before clinical events evolve. Cardiac computed tomography (CT) is an emerging noninvasive imaging tool, which can visualize the entire coronary tree with submillimeter resolution. We reviewed the current status of cardiac CT to qualitatively and quantitatively determine coronary plaque dimensions and composition, and its potential to improve our understanding of the natural history of coronary artery disease as well as prevention of cardiovascular events.

PMID: 20129522 [PubMed - as supplied by publisher]

More 

Role of Cardiac Multidetector Computed Tomography in Acute Ischemic Stroke: A Preliminary Report.

Cerebrovasc Dis. 2010 Jan 30;29(4):313-320

Authors: Ko SB, Choi SI, Chun EJ, Ko Y, Park JH, Lee SJ, Lee J, Han MK, Bae HJ

Background and Purpose: Cardiac multidetector computed tomography (MDCT) is less dependent upon the patient’s condition and may be valuable in the diagnosis of embolic sources when the patient’s cooperation is limited due to a neurologic deficit. However, its role has never been validated in acute stroke patients whose stroke mechanism is assumed to be embolic. Methods: Consecutive patients who were admitted with acute ischemic stroke from May 1, 2007 to November 30, 2007 were included in this study. Inclusion criteria were (1) any cardiac evidence of high-risk embolic sources for cerebral embolism, or (2) radiological or (3) clinical evidence of embolic stroke. All patients underwent transthoracic echocardiography first, and then cardiac MDCT or transesophageal echocardiography (TEE) was attempted, if possible. The results and feasibility of cardiac MDCT and TEE were compared. Results: One hundred and forty-three patients met the inclusion criteria. Cardiac MDCT was performed in 124 patients (86.7%), TEE in 83 patients (57.3%), whereas 75 patients (52.4%) underwent both studies. Renal insufficiency for cardiac MDCT and lack of cooperation for TEE were found to be the most impeding factors. Among the patients with both evaluations, cardiac MDCT identified a high-risk intracardiac embolic source in 8 and an extracardiac source in 20, while TEE found an intracardiac source in 1 and an extracardiac source in 7. Statistically significant differences were found with respect to detecting cardioembolic sources and high-risk aortic atheroma. Conclusions: Cardiac MDCT is a feasible and accurate diagnostic tool for embolic sources in an acute stroke setting.

PMID: 20130396 [PubMed - as supplied by publisher]

See the original post here 

Assessment of left ventricular function in non-dilated and dilated hearts: comparison of contrast-enhanced 2-dimensional echocardiography with multi-detector row CT angiography.

Acta Cardiol. 2009 Dec;64(6):787-94

Authors: Burianová L, Riedlbauchová L, Lefflerová K, Marek T, Lupínek P, Kautznerova D, Vedlich D, Lánska V, Kautzner J

OBJECTIVE: Multidetector-row CT (MDCT) and contrast-enhanced echocardiography (CEE) are being increasingly used for assessment of left ventricular (LV) function. Excellent spatial and contrast resolution of MDCT allows this evaluation along with coronary angiography. CEE improves the accuracy of 2D echocardiography. Data on side-by-side comparison of both techniques for assessment of LV size and function in subjects with a non-dilated or dilated left ventricle are limited. METHODS AND RESULTS: Our study population included 64 patients. Group I included 31 patients with an implanted pacemaker who had a non-dilated left ventricle with preserved systolic function. Group II comprised 33 patients with dilated cardiomyopathy and severe systolic LV dysfunction. LV end-diastolic and end-systolic volumes (LVEDV, LVESV) and ejection fraction (LVEF) were assessed using both CEE and short-axis MDCT. The results obtained by both techniques were compared by linear regression and Bland-Altman analysis. Additionally, intra- and interobserver reproducibility was assessed. Both CEE and MDCT measurements highly correlated (r = 0.61-0.94). However, CEE significantly underestimated LVEDV and LVESV, and this bias was higher with enlarged LV volumes. LVEF was overestimated by CEE in both groups with a higher bias in the group with preserved systolic function. Both intra- and interobserver reproducibility was significantly better for MDCT, the worst reproducibility was observed for CEE in group I. CONCLUSION: Despite a high correlation between MDCT and CEE measurements, CEE provides consistently lower volumes and higher LVEF. This suggests that both methods are not completely interchangeable. Reproducibility of CEE is inferior to reproducibility of MDCT, especially in non-dilated left ventricles with preserved function.

PMID: 20128156 [PubMed - in process]

Read more

Atrial electrophysiological and structural remodeling in high-risk patients with Brugada syndrome: Assessment with electrophysiology and echocardiography.

Heart Rhythm. 2010;7(2):218-224

Authors: Toh N, Morita H, Nagase S, Taniguchi M, Miura D, Nishii N, Nakamura K, Ohe T, Kusano KF, Ito H

BACKGROUND: Atrial fibrillation (AF) often occurs in Brugada syndrome (BrS), and BrS patients with spontaneous AF often experience ventricular fibrillation (VF) attacks. Atrial vulnerability providing a substrate for AF is known to be enhanced in BrS, but there are no data on atrial structural attributes. OBJECTIVE: The objective of this study was to assess atrial electrophysiological and structural characteristics in BrS and their relationships with gene mutations. METHODS: We studied 57 patients with BrS. Intra-atrial conduction time (CT) was defined as the interval from the stimulus at the high right atrium to atrial deflection at the distal portion of the coronary sinus. Left atrial volume index (LAVI) was measured by the modified Simpson method at left ventricular end-systole using echocardiography. SCN5A mutations were analyzed in all patients. RESULTS: In patients with documented VF, spontaneous AF frequently occurred and prolonged CT and increased LAVI were observed compared with those in patients without VF (all P < .05; LAVI: 22 +/- 5 vs. 32 +/- 7 ml/m(2)). Even among patients without AF, CT and LAVI were still increased in patients with VF (all P < .05; LAVI: 22 +/- 5 vs. 29 +/- 5 ml/m(2)). The presence of SCN5A mutation was associated with prolonged CT (P < .05) and increased LAVI (P < .01), but not with arrhythmic episodes. CONCLUSION: Both atrial vulnerability and structural remodeling are enhanced in high-risk patients with BrS, even in those without AF. These morphological characteristics suggest that BrS is a form of genetic myocardial disease.

PMID: 20129298 [PubMed - as supplied by publisher]

Read more here