Assessment of regional left ventricular function with multidetector-row computed tomography versus magnetic resonance imaging.

This study compares quantitative and qualitative information on global and regional left ventricular (LV) function obtained with multidetector-row computed tomography (MDCT) with that obtained with magnetic resonance imaging (MRI) in patients with a high prevalence of LV wall motion abnormalities. Thirty patients (19 male, 63.7+/-15.1 years) with myocardial infarction (n=12), coronary artery disease (n=9), arrhythmogenic right ventricular cardiomyopathy (n=6), and dilation cardiomyopathy (n=3) were included. Segmental LV wall motion (LV-WM) was assessed using a 4-point scale. Wall thickness measurements were calculated in diastolic and systolic short axis images. Two hundred and fifty-two out of 266 (94.7%) normal and 189 out of 214 (88.3%) segments with decreased wall motion were correctly identified by MDCT, yielding a sensitivity of 88% and specificity of 95% for identification of wall motion abnormalities. LV-WM scores were identical in 86.7% of 480 segments (kappa=0.809). MDCT had a tendency to underestimate the degree of wall motion impairment. Interobserver agreement was lower in MDCT (66.5%) than in MRI (89.1%; p<0.01). Normokinetic segments are reliably identified with MDCT. Sensitivity for detection and accurate classification of LV wall motion abnormalities need to be improved. Better temporal resolution of the CT system seems to be the most important factor for enhancing MDCT performance.

Idiopathic left ventricular aneurysm and sudden cardiac death in young adults.

AIMS: We report three young patients presenting with life-threatening ventricular tachycardia (VT) or ventricular fibrillation (VF) and/or survived sudden cardiac arrest, who were admitted to our institution for further diagnostic evaluation. METHODS AND RESULTS: In all patients, idiopathic left ventricular (LV) aneurysms were identified after a detailed non-invasive and invasive evaluation. Sustained VT/VF was inducible during programmed ventricular stimulation in two of the three patients. Left ventricular aneurysms were depicted and characterized by various imaging modalities (echocardiography, magnetic resonance imaging, LV angiography). To elucidate the pathogenesis further, both myocardial viability and regional sympathetic innervation were assessed by radionuclide imaging techniques. Defects of innervation and metabolism were documented in the area of the aneurysm but distal to the aneurysm there were no signs of downstream denervation. CONCLUSION: Life-threatening arrhythmias may be the first manifestation of an idiopathic LV aneurysm, which can be reliably diagnosed with modern imaging techniques. Radionuclide imaging may yield additional information as to the involvement of the autonomic nervous system potentially associated with arrhythmogenesis. Management strategies in patients with an idiopathic LV aneurysm range from antiarrhythmic drug treatment, implantation of an automatic cardioverter-defibrillator to surgical aneurysmectomy.

MDCT determination of volume and function of the left ventricle: are short-axis image reformations necessary?

OBJECTIVE: Determination of left ventricular (LV) volumes and global function parameters from MDCT data sets is usually based on short-axis reformations from primarily reconstructed axial images, which prolong postprocessing time. The aim of this study was to evaluate the feasibility of LV volumetry and global LV function assessment from axial images in comparison with short-axis image reformations. SUBJECTS AND METHODS: This study consisted of 20 patients with either coronary artery disease or dilated cardiomyopathy. We evaluated MDCT results using cine MRI as the reference technique. RESULTS: LV end-diastolic volume (LVEDV) and end-systolic volume (LVESV) were significantly overestimated by the axial MDCT approach in comparison with volume measurements from short-axis CT image reformations. The mean LV ejection fraction (LVEF) was not significantly different (41.2% vs 42.7%). Short-axis and axial MDCT determination of LVEF revealed a systematic underestimation by a mean +/- SD of -2.1% +/- 3.6% versus -3.6% +/- 8.2%, respectively, when compared with LVEF values based on cine MRI. The interobserver variability for volume and function measurements from axial images (LVEDV = 8.5%, LVESV = 10.8%, LVEF = 9.6%) was slightly higher than those measurements from short-axis reformations (LVEDV = 7.2%, LVESV = 9.5%, LVEF = 8.7%). The mean total evaluation time was significantly shorter using axial images (14.1 +/- 3.9 min) compared with short-axis reformations (16.9 +/- 5.2 min) (p < 0.05). CONCLUSION: Determination of LV volumes and assessment of global LV function from axial MDCT image reformations is feasible and time efficient. This approach might be a clinically useful alternative to established short-axis-based measurements in patients with normal or near-normal LV function. A progressive underestimation of LVEF with increasing LV volumes may limit the clinical applicability of the axial approach in patients with dilated cardiomyopathy.

Left bundle branch block in chronic heart failure-impact on diastolic function, filling pressures, and B-type natriuretic peptide levels.

BACKGROUND: For patients with chronic heart failure (CHF), left bundle branch block (LBBB) is associated with impaired systolic function and increased morbidity and mortality, but data on diastolic function are scarce. In this patient population, we attempted to define the impact of LBBB on diastolic function, filling pressures, and brain natriuretic peptide and its circulating N-terminal precursor (NT-proBNP) levels. METHODS: A total of 94 patients with stable CHF (48 with complete LBBB, 46 without intraventricular conduction delay and normal QRS duration) underwent conventional 2-dimensional/Doppler echocardiography and Doppler tissue analysis of mitral annular velocities. As a measure of left ventricular filling pressures, the ratio of peak early mitral flow velocity to peak early diastolic mitral annular velocity was derived. NT-proBNP measurements were carried out on a bench-top analyzer (Elecsys-2010, Roche Diagnostics, Mannheim, Germany). RESULTS: Patients with or without LBBB did not differ with respect to the cause of CHF or ejection fraction, but in LBBB deceleration time was shorter (163 +/- 66 vs 205 +/- 95 milliseconds, P = .021) and a restrictive mitral filling pattern was more frequent (35% vs 11%, P = .005). In such patients, the ratio of peak early mitral flow velocity to peak early diastolic mitral annular velocity was higher (14.5 +/- 6.2 vs 10.6 +/- 5.2, P < .001) and NT-proBNP was elevated (3553 +/- 3725 vs 850 +/- 896 pg/mL, P < .01) as compared with patients without LBBB. CONCLUSION: For patients with CHF and comparable systolic performance, LBBB is associated with more severe diastolic dysfunction, elevated filling pressures, and higher NT-proBNP levels. These findings may contribute to increased morbidity and mortality of such patients.

Prognostic value of tissue Doppler imaging in patients with chronic congestive heart failure.

BACKGROUND: The prognostic value of tissue Doppler imaging (TDI) in patients with chronic congestive heart failure (CHF) has not been compared against conventional measures of systolic, diastolic and overall left ventricular LV performance. The aim of this study was to assess the prognostic value of TDI-derived parameters in patients with CHF. METHODS: One hundred thirty-two subjects with chronic CHF [due to ischemic (n=82) or dilated (n=50) cardiomyopathy, 101 males, mean age 57+/-11 years] underwent conventional two-dimensional/Doppler echocardiography and assessment of the Tei-index (isovolumic contraction time and isovolumic relaxation time divided by ejection time). Systolic, early and late diastolic mitral annular velocities (S', E' and A') were derived from pulsed TDI. A cardiac event (cardiac death, urgent cardiac transplantation or hospitalization due to decompensated CHF) was defined as the combined study endpoint. RESULTS: The patients were followed for a mean of 224+/-123 days. Thirty-one patients suffered an event (cardiac death, n=5; urgent cardiac transplantation, n=2; hospitalization due to CHF, n=24). In patients with event, ejection fraction was lower (25+/-10 vs. 32+/-9%), mitral deceleration time was shorter (138+/-58 vs. 193+/-72 ms), and the peak mitral E/E'-ratio (16.1+/-6.6 vs. 10.6+/-5.0) was significantly elevated as compared to patients free of events (p<0.001 for all comparisons). In those patients, the Tei-index was elevated (1.09+/-0.39 vs. 0.86+/-0.26, p<0.01), and a restrictive mitral filling pattern was more frequent (51.6 vs. 17.5%, p<0.001). Stepwise multivariate analysis identified the mitral E/E'-ratio (p<0.001) and the Tei-index (p=0.019) as the only independent predictors of a combined event. E/E'-ratio was the best predictor of hospitalization due to CHF also. In patients with mitral E/E'-ratio>12.5 or Tei-index>0.90, outcome was poor. CONCLUSIONS: In subjects with chronic CHF, the mitral E/E'-ratio is a stronger predictor of future cardiac events than conventional parameters of systolic, diastolic or overall LV performance. The E/E'-ratio may be a useful addition in the routine follow-up of such patients.

Electrocardiography and Doppler echocardiography for risk stratification in patients with chronic heart failure: incremental prognostic value of QRS duration and a restrictive mitral filling pattern.

OBJECTIVES: This prospective study tested whether Doppler echocardiographic variables add incremental value to QRS duration in determining the prognosis of patients with chronic heart failure (CHF) and systolic dysfunction. BACKGROUND: Diastolic dysfunction frequently is observed in patients with CHF, but its prognostic impact relative to that of QRS duration is unknown. METHODS: A total of 193 patients with CHF and an ejection fraction <45% were enrolled prospectively. Echo measurements included left ventricular dimensions/volumes, ejection fraction, mitral early/late diastolic velocity ratio, deceleration time, and tissue Doppler mitral annular velocities. The mitral filling pattern was classified as either restrictive (RFP) or nonrestrictive. A cardiac event (cardiac death or urgent cardiac transplantation) was defined as combined study end point. RESULTS: During a follow-up of 385 +/- 270 days, 24 patients suffered an event (cardiac death, n = 21; urgent transplantation, n = 3). The RFP, QRS duration, left ventricular systolic diameter, and mitral annular early diastolic velocity were independent predictors of an event. In patients with QRS duration >144 ms, the outcome was markedly poorer in the presence of RFPs as compared with their absence. Similarly, despite a QRS duration

Safe performance of magnetic resonance imaging on a patient with an ICD.

This is a report on a patient with an implanted cardioverter defibrillator (ICD) who intentionally underwent magnetic resonance imaging (MRI) of a malignant brain tumor. To avoid inadequate detection of ventricular tachycardia (VT) or ventricular fibrillation (VF), the ICD was inactivated by programming the VT-detection and VT/VF-therapy status off. The patient came through the protocol safely and without any difficulty or discomfort. There was no arrhythmic event. MRI affected neither programmed data nor the function of the ICD system.

Usefulness of tissue Doppler imaging for estimation of left ventricular filling pressures in patients with systolic and diastolic heart failure.

The diagnostic usefulness of the mitral E/E' ratio (derived from tissue Doppler imaging) as an estimate of left ventricular filling pressures was studied in 28 patients with diastolic heart failure (defined by heart failure signs and symptoms but with preserved ejection fraction) and in 46 patients with systolic heart failure (heart failure signs and symptoms and reduced ejection fraction). E/E' was reflective of filling pressures in subjects with diastolic and systolic heart failure and may be of special use in ruling out elevated filling pressures in subjects with suspected diastolic heart failure.

Multi-detector row computed tomography of the heart: does a multi-segment reconstruction algorithm improve left ventricular volume measurements?

A multi-segment cardiac image reconstruction algorithm in multi-detector row computed tomography (MDCT) was evaluated regarding temporal resolution and determination of left ventricular (LV) volumes and global LV function. MDCT and cine magnetic resonance (CMR) imaging were performed in 12 patients with known or suspected coronary artery disease. Patients gave informed written consent for the MDCT and the CMR exam. MDCT data were reconstructed using the standard adaptive cardiac volume (ACV) algorithm as well as a multi-segment algorithm utilizing data from three, five and seven rotations. LV end-diastolic (LV-EDV) and end-systolic volumes and ejection fraction (LV-EF) were determined from short-axis image reformations and compared to CMR data. Mean temporal resolution achieved was 192+/-24 ms using the ACV algorithm and improved significantly utilizing the three, five and seven data segments to 139+/-12, 113+/-13 and 96+/-11 ms (P<0.001 for each). Mean LV-EDV was without significant differences using the ACV algorithm, the multi-segment approach and CMR imaging. Despite improved temporal resolution with multi-segment image reconstruction, end-systolic volumes were less accurately measured (mean differences 3.9+/-11.8 ml to 8.1+/-13.9 ml), resulting in a consistent underestimation of LV-EF by 2.3-5.4% in comparison to CMR imaging (Bland-Altman analysis). Multi-segment image reconstruction improves temporal resolution compared to the standard ACV algorithm, but this does not result in a benefit for determination of LV volume and function.

Tissue Doppler imaging in patients with moderate to severe aortic valve stenosis: clinical usefulness and diagnostic accuracy.

BACKGROUND: Mitral annular velocities derived from tissue Doppler imaging (TDI) provide information about left ventricular (LV) long-axis function and allow for the assessment of LV filling pressures in selected subsets of patients. It was the aim of this study to assess the usefulness of TDI in patients with moderate to severe aortic valve stenosis (AS). METHODS: Twenty-three patients with moderate to severe AS (mean aortic valve area 0.8 +/- 0.4 cm2), in whom coronary artery disease had been ruled out, and 36 asymptomatic age-matched control subjects underwent assessment of ejection fraction, fractional shortening, and mitral inflow (E, A, E/A ratio). TDI velocities (S', E', A') were derived from the septal mitral annulus. In patients with AS, LV pressure before atrial contraction (LV pre-A pressure), LV end-diastolic pressure, and cardiac index were measured during cardiac catheterization. RESULTS: In patients with AS, systolic (S') and early diastolic mitral annular velocities (E') were significantly reduced in comparison to control subjects (systolic, 5.5 +/- 1.2 vs 8.3 +/- 1.3 cm/s; early diastolic, 5.6 +/- 1.6 vs 10.2 +/- 3.0 cm/s, P <.001 for both comparisons), but ejection fraction, fractional shortening, and cardiac index were normal. In patients with AS, LV pre-A pressures (14 +/- 4 mm Hg) and end-diastolic pressures were high (19 +/- 7 mm Hg). In such patients, the mitral E/E' ratio was significantly related to LV pre-A pressure (r = 0.75, P <.001) and to LV end-diastolic pressure (r = 0.78, P <.001). In patients with AS, an E/E' ratio > or =13 identified an LV end-diastolic pressure >15 mm Hg, with a sensitivity of 93% and a specificity of 88%. CONCLUSIONS: In patients with moderate to severe AS, TDI allows for a reliable, noninvasive estimation of filling pressures. In such patients, systolic long-axis function is impaired even in the presence of normal ejection fraction and cardiac index. Thus, TDI integrates information about systolic and diastolic performance and may be a useful addition in the echocardiographic workup and care of patients with AS.

Multi-detector row CT of left ventricular function with dedicated analysis software versus MR imaging: initial experience.

PURPOSE: To determine left ventricular (LV) volumetric and functional parameters from retrospectively electrocardiographically gated multi-detector row computed tomography (CT) by using semiautomated analysis software and to correlate results with those of magnetic resonance (MR) imaging. MATERIALS AND METHODS: In 30 patients (mean age, 59.2 years +/- 7.1 [SD]) known to have or suspected of having coronary artery disease, four-channel multi-detector row CT was performed with standard technique, and diastolic and systolic image reconstructions were generated. With commercially available analysis software capable of semiautomated contour detection, end diastolic and end systolic LV volumes were determined from short-axis secondary CT reformations. Steady-state free-precession cine MR images were acquired in short-axis orientation within 48 hours and analyzed by using dedicated software. Bland-Altman analysis was performed to calculate limits of agreement and systematic errors between CT and MR imaging. RESULTS: Mean end diastolic (138.8 mL +/- 31.9) and end systolic (53.9 mL +/- 21.2) LV volumes as determined with CT correlated well with MR imaging measurements (142.0 mL +/- 32.5 [r = 0.93] and 54.9 mL +/- 22.8 [r = 0.94], respectively [P <.001]). LV ejection fraction (61.6% +/- 10.6 for CT vs 62.3% +/- 10.1 for MR imaging; r = 0.89) and stroke volume (84.6 mL +/- 20.9 for CT vs 86.9 mL +/- 21.5 for MR imaging; r = 0.88) also showed good correlation (P <.001). Bland-Altman analysis showed acceptable limits of agreement (+/-9.8% for ejection fraction) without systematic errors. CONCLUSION: In selected patients, semiautomated analysis software enables LV volumetric and functional analysis based on multi-detector row CT data sets, the results of which correlate well with MR imaging findings.

Evaluation of global left ventricular myocardial function with electrocardiogram-gated multidetector computed tomography: comparison with magnetic resonance imaging.

RATIONALE AND OBJECTIVES: Electrocardiogram-gated 3D volume data from multidetector computed tomography coronary angiography (MDCT-CA) enable image reconstruction in any phase of the cardiac cycle. The objective was to determine left ventricular (LV) function parameters by MDCT in comparison to cine magnetic resonance imaging (MRI). METHOD: Thirty patients with known or suspected coronary artery disease (CAD) underwent MDCT-CA. From multiplanar reformations in short axis orientation end-diastolic and end-systolic LV volumes (LVEDV, LVESV) were determined to calculate LV stroke volume and ejection fraction (LVSV, LVEF) and compared with MRI measurements. RESULTS: LVEDV (147 +/- 27 mL) and LVESV (65 +/- 22 mL) determined by MDCT correlated well to the respective MRI measurements (LVEDV 133 +/- 27 mL, r = 0.80, P < 0.001; LVESV 48 +/- 19 mL, r = 0.89, P < 0.001). LVSV (MDCT 82 +/- 15 mL; MRI 85 +/- 17 mL; r = 0.77, P < 0.001) and LVEF (MDCT 56 +/- 9%; MRI 65 +/- 8%; r = 0.85, P < 0.001) showed a good correlation as well. LVEF was significantly underestimated by MDCT (-8.5 +/- 4.7%, P < 0.001). CONCLUSIONS: Initial experience in patients evaluated for CAD shows that spiral MDCT studies may provide LV functional data in good correlation to Cine MRI.

Imaging of coronary artery stents using multislice computed tomography: in vitro evaluation.

The aim of this study was to evaluate imaging features of different coronary artery stents during multislice CT Angiography (MSCTA). Nineteen stents made of varying material (steel, nitinol, tantalum) and of varying stent design were implanted in plastic tubes with an inner diameter of 3 mm to simulate a coronary artery. The tubes were filled with iodinated contrast material diluted to 200 Hounsfield units (HU), closed at both ends and positioned in a plastic container filled with oil (-70 HU). The MSCT scans were obtained perpendicular to the stent axes (detector collimation 4x1 mm, table feed 2 mm/rotation, 300 mAs, 120 kV). Axial images and multiplanar reformations were evaluated regarding artifact size, lumen visibility, and intraluminal attenuation values. Artifacts characterized by artifactual thickening of the stent struts leading to apparent reduction in the lumen diameter and increased intraluminal attenuation values were observed in all cases. The stent lumen was totally obscured in the Wiktor stent, the Wallgraft stent, and the Nir Royal stent. Partial residual of the stent lumen could be visualized in all other utilized stent products (artificial lumen reductions ranged from 62% in the V-Flex stent to 94% in the Bx Velocity stent). Parts of the stent lumen can be visualized in most coronary artery stents; however, detectability of in-stent stenoses remains to be evaluated for each stent type.

Using ECG-gated multidetector CT to evaluate global left ventricular myocardial function in patients with coronary artery disease.

OBJECTIVE: Retrospectively ECG-gated three-dimensional volume data from multidetector CT (MDCT) coronary angiography enable image reconstruction of the cardiac cycle in the diastolic and systolic phases. The objective of our study was to investigate the feasibility of determining left ventricular function from MDCT coronary angiography data sets in 22 patients with coronary artery disease and to study the correlation of MDCT results with those of functional data from biplane cineventriculography. CONCLUSION: Multiplanar reformations from three-dimensional MDCT data allowed good delineation of endocardial and epicardial left ventricular contours. In patients evaluated for coronary artery disease, MDCT coronary angiography with retrospective ECG gating provides functional data in an acceptable correlation (r = 0.8; p < 0.05) to biplane cineventriculography.

Contrast transcranial Doppler ultrasound in the detection of right-to-left shunts: comparison of Echovist-200 and Echovist-300, timing of the Valsalva maneuver, and general recommendations for the performance of the test.

BACKGROUND AND PURPOSE: Cardiac right-to-left shunts (RLS) can be identified by transesophageal echocardiography (TEE) as well as by transcranial Doppler ultrasound (TCD) using contrast agents, such as Echovist-200 or Echovist-300 in conjunction with a Valsalva maneuver (VM) as provocation procedure. Both Echovist preparations are in use. Currently, the appropriate timing of the VM is still under debate. METHODS: Sixty-four patients were investigated by both TEE and bilateral TCD of the middle cerebral arteries. The following protocol was applied in a randomized way: (1) no VM, (2) VM for 5 s starting with the beginning of Echovist-300 injection, (3) VM for 5 s starting 5 s after the beginning of Echovist-300 injection, (4) VM for 5 s starting 10 s after the beginning of Echovist-300 injection, and (5) VM for 5 s starting 5 s after the beginning of Echovist-200 injection. RESULTS: In 27 patients, an RLS was demonstrated by both TEE and contrast TCD (shunt-positive). Twenty-two patients were negative in both investigations, no patient was positive on TEE but negative on TCD, 15 patients were only positive on at least one TCD investigation but negative on TEE. Tests 3 and 5 were the most appropriate ones; test 3 was slightly superior to test 5. CONCLUSIONS: TCD using Echovist-300 or Echovist-200 is a sensitive method to identify TEE-proven cardiac RLS. To achieve the best diagnostic accuracy, the VM should be performed for a duration of 5 s starting at 5 s following the beginning of contrast injection.