Biomedical subjects

Hildo J Lamb

Publications and source records attributed to Hildo J Lamb.

At least 19 recordsLinked to original sources

PubMed2007

Assessment of right ventricular infarction with contrast-enhanced magnetic resonance imaging.

OBJECTIVE: Evaluation of contrast-enhanced magnetic resonance imaging to assess right ventricular infarction in patients with acute inferior myocardial infarction. BACKGROUND: Contrast-enhanced magnetic resonance imaging has been used for assessing scar tissue after left ventricular infarction. The value of contrast-enhanced magnetic resonance imaging to assess right ventricular infarction is unknown and was evaluated. METHODS: Consecutive patients (n=18) with first acute inferior infarction were included. Resting electrocardiogram and right-sided electrocardiogram were acquired to assess right ventricular involvement. Resting cine magnetic resonance imaging was performed to evaluate right ventricular function and volumes, whereas the extent of right ventricular scar tissue was assessed by contrast-enhanced magnetic resonance imaging. Cine magnetic resonance imaging was repeated at 6-months follow-up to re-assess right ventricular function and volumes. RESULTS: Sensitivity and specificity of magnetic resonance imaging were 100 and 78%, respectively, to detect right ventricular infarction (using the right-sided electrocardiogram as the gold standard). At 6 months follow-up, patients with scar tissue on contrast-enhanced magnetic resonance imaging showed right ventricular dilatation. Moreover, the extent of right ventricular scar tissue was linearly related to the severity of right ventricular dilatation. CONCLUSIONS: Contrast-enhanced magnetic resonance imaging permits accurate assessment of right ventricular scar tissue. Patients with extensive right ventricular infarction demonstrate right ventricular dilatation at 6 months follow-up.

Adult↗

PubMed2006

Relationship between noninvasive coronary angiography with multi-slice computed tomography and myocardial perfusion imaging.

OBJECTIVES: The aim of this study was to perform a head-to-head comparison between multi-slice computed tomography (MSCT) and myocardial perfusion imaging (MPI) in patients with an intermediate likelihood of coronary artery disease (CAD) and to compare non-invasive findings to invasive coronary angiography. BACKGROUND: Multi-slice computed tomography detects atherosclerosis, whereas MPI detects ischemia; how these 2 techniques compare in patients with an intermediate likelihood of CAD is unknown. METHODS: A total of 114 patients, mainly with intermediate likelihood of CAD, underwent both MSCT and MPI. The MSCT studies were classified as having no CAD, nonobstructive (<50% luminal narrowing) CAD, or obstructive CAD. Myocardial perfusion imaging examinations were classified as showing normal or abnormal (reversible and/or fixed defects). In a subset of 58 patients, invasive coronary angiography was performed. RESULTS: On the basis of the MSCT data, 41 patients (36%) were classified as having no CAD, of whom 90% had normal MPI. A total of 33 patients (29%) showed non-obstructive CAD, whereas at least 1 significant (> or =50% luminal narrowing) lesion was observed in the remaining 40 patients (35%). Only 45% of patients with an abnormal MSCT had abnormal MPI; even in patients with obstructive CAD on MSCT, 50% still had a normal MPI. In the subset of patients undergoing invasive angiography, the agreement with MSCT was excellent (90%). CONCLUSIONS: Myocardial perfusion imaging and MSCT provide different and complementary information on CAD, namely, detection of atherosclerosis versus detection of ischemia. As compared to invasive angiography, MSCT has a high accuracy for detecting CAD in patients with an intermediate likelihood of CAD.

Aged↗

PubMed2006

Global and regional left ventricular function: a comparison between gated SPECT, 2D echocardiography and multi-slice computed tomography.

PURPOSE: Global and regional left ventricular (LV) function are important indicators of the cardiac status in patients with coronary artery disease (CAD). Therapy and prognosis are to a large extent dependent on LV function. Multi-slice computed tomography (MSCT) has already earned its place as an imaging modality for non-invasive assessment of the coronary arteries, but since retrospective gating to the patient's ECG is performed, information on LV function can be derived. METHODS: In 49 patients with known or suspected CAD, coronary angiography with MSCT imaging was performed, in addition to gated SPECT and 2D echocardiography. LV end-diastolic and LV end-systolic volumes and LV ejection fraction were analysed with dedicated software (CMR Analytical Software System, Medis, Leiden, The Netherlands for MSCT; gated SPECT by QGS, Cedars-Sinai Medical Center, Los Angeles, CA, USA), and by the biplane Simpson's rule for 2D echocardiography. Regional wall motion was evaluated according to a 17-segment model and a three-point score system. RESULTS: Correlations were fairly good between gated SPECT and MSCT (LVEDV: r=0.65; LVESV: r=0.63; LVEF: r=0.60), and excellent between 2D echocardiography and MSCT (LVEDV: r=0.92; LVESV: r=0.93; LVEF: r=0.80). Agreement for regional wall motion was 95% (kappa=0.66) between gated SPECT and MSCT, and 96% (kappa=0.73) between 2D echocardiography and MSCT. CONCLUSION: Global and regional LV function and LV volumes can be adequately assessed with MSCT. Correlations with 2D echocardiography are stronger than with gated SPECT.

Coronary Artery Disease↗

PubMed2006

Diagnostic accuracy of 64-slice multislice computed tomography in the noninvasive evaluation of significant coronary artery disease.

The purpose of the present study was to determine the diagnostic accuracy of current 64-slice multislice computed tomography (MSCT) in the detection of significant coronary artery disease, using conventional coronary angiography as the gold standard. In 61 patients scheduled for conventional coronary angiography, 64-slice MSCT was performed and evaluated for the presence of significant (>or=50% luminal narrowing) stenoses. One patient had to be excluded because of a heart rate>90 beats/min during data acquisition. In the remaining 60 patients (46 men, 14 women; average age 60+/-11 years), 854 segments were available for evaluation. Of these segments 842 (99%) were of sufficient image quality. Conventional coronary angiography identified 73 lesions, of which 62 were detected by MSCT. The corresponding sensitivity and specificity were 85% and 97%, respectively. On a patient-per-patient analysis, sensitivity, specificity, and positive and negative predictive values were 94%, 97%, 97%, and 93%, respectively. In conclusion, the present study confirms that 64-slice MSCT enables the accurate and noninvasive evaluation of significant coronary artery stenoses.

Adolescent↗

PubMed2006

Assessment of left ventricular dyssynchrony in patients with conduction delay and idiopathic dilated cardiomyopathy: head-to-head comparison between tissue doppler imaging and velocity-encoded magnetic resonance imaging.

OBJECTIVES: This study sought to compare tissue Doppler imaging (TDI) with velocity-encoded (VE) magnetic resonance imaging (MRI) for left ventricular (LV) dyssynchrony assessment. BACKGROUND: Cardiac resynchronization therapy (CRT) is proposed for patients with heart failure, depressed LV function, and a wide QRS complex. Selection is based mainly on electrocardiogram criteria, but recent data suggest that intraventricular dyssynchrony may be preferred for selection. An LV dyssynchrony can adequately be assessed with TDI, but this has not been compared directly with other imaging modalities. A VE MRI potentially allows direct myocardial wall motion measurements similar to TDI. METHODS: Twenty patients with heart failure, systolic LV dysfunction, and a wide QRS complex were included, as well as 10 normal individuals with normal QRS duration and LV function. The TDI and VE MRI data were acquired to study intraventricular dyssynchrony. RESULTS: Left ventricular dyssynchrony was not observed in normal individuals (mean dyssynchrony -2 +/- 15 ms on TDI; mean -5 +/- 17 ms on MRI, p = NS). In patients, mean LV dyssynchrony was 55 +/- 37 ms on TDI; 49 +/- 38 ms on MRI (p = NS). Good correlation between both modalities was observed (linear regression TDI = 0.99 x MRI - 5, n = 30, r = 0.98, p < 0.01). The MRI showed a small, nonsignificant underestimation of 5 +/- 8 ms compared with TDI. Agreement between MRI and TDI for classification according to severity of LV dyssynchrony (minimal, intermediate, and extensive) was excellent (kappa +/- SE = 0.96 +/- 0.07, p < 0.01) with 95% of patients classified identical. CONCLUSIONS: Both MRI and TDI yield comparable information on LV dyssynchrony; MRI is useful in the selection of patients for CRT.

Adult↗

PubMed2006

Usefulness of intramyocardial injection of autologous bone marrow-derived mononuclear cells in patients with severe angina pectoris and stress-induced myocardial ischemia.

Bone marrow cell transplantation has been proposed as a novel therapeutic option for patients with coronary artery disease. This study investigated whether autologous bone marrow-derived mononuclear cell injection into the ischemic myocardium of patients with severe angina pectoris could safely reduce anginal symptoms, improve myocardial perfusion, and increase left ventricular (LV) function. In a total of 20 patients (63 +/- 10 years old; 16 men) with angina pectoris, myocardial segments with stress-induced ischemia as assessed by gated single-photon emission computed tomography were injected with 30 to 100 million mononuclear cells. Anginal symptoms, Canadian Cardiovascular Society class, and quality of life were assessed at 3 and 6 months of follow-up. At baseline and 3 months of follow-up, an exercise test, gated single-photon emission computed tomography, and magnetic resonance imaging were performed to assess exercise capacity, myocardial perfusion, and LV function. Intramyocardial injection of autologous bone marrow-derived mononuclear cells was safe. The Canadian Cardiovascular Society class improved from 3.5 +/- 0.5 at baseline to 2.4 +/- 0.6 after 3 months (p <0.01) and 2.4 +/- 0.6 after 6 months (p <0.01). The quality-of-life score improved from 52 +/- 10% to 71 +/- 10% at 3 months (p <0.01) to 73 +/- 15% at 6 months (p <0.01). The exercise capacity increased from 79 +/- 31% to 84 +/- 29% (p <0.05). Magnetic resonance imaging revealed an increased LV ejection fraction from 51 +/- 11% to 54 +/- 10% (p <0.01) and a reduced LV end-systolic volume from 97 +/- 50 to 88 +/- 42 ml (p <0.01). The wall motion score index improved from 0.36 +/- 0.32 to 0.24 +/- 0.28 (p <0.01). The number of segments with stress-induced ischemia decreased from 5.1 +/- 3.2 to 2.3 +/- 2.6 (p<0.01). In conclusion, autologous bone marrow-derived mononuclear cell injection in patients with ischemia is safe, reduces anginal symptoms, improves myocardial perfusion, and increases LV function.

Angina Pectoris↗

PubMed2006

Relation of B-type natriuretic peptide early after acute myocardial infarction to left ventricular diastolic function and extent of myocardial damage determined by magnetic resonance imaging.

Early after acute myocardial infarction, the relation between plasma B-type natriuretic peptide (BNP) and extent of myocardial scar formation and diastolic dysfunction remains unclear. In 32 consecutive patients early (5 +/- 3 days) after a first acute myocardial infarction, delayed contrast-enhanced magnetic resonance (MR) imaging was performed to define myocardial scar. Diastolic function was assessed using phase-contrast MR measurements of mitral flow and septal tissue velocities (tissue MR imaging) to estimate left ventricular (LV) filling pressures. MR study was immediately followed by BNP measurement. BNP related to LV ejection fraction (r = -0.52, p = 0.002), extent of myocardial scar (percent delayed hyperenhancement of LV mass, r = 0.49, p = 0.005; transmural index, r = 0.58, p <0.001), and estimated LV filling pressures (ratio of early diastolic mitral flow velocity to early diastolic mitral annular velocity, r = 0.51, p = 0.003). In multivariate analysis, transmural index and early diastolic mitral flow velocity/early diastolic mitral annular velocity were independent predictors of BNP levels (p <0.05, power of 0.99 at alpha = 0.05). In conclusion, among patients with recent myocardial infarction, high BNP levels are independently associated with extent of myocardial scar tissue and estimated LV filling pressures.

Blood Flow Velocity↗

PubMed2006

Effect of posterolateral scar tissue on clinical and echocardiographic improvement after cardiac resynchronization therapy.

BACKGROUND: Currently, one third of patients treated with cardiac resynchronization therapy (CRT) do not respond. Nonresponse to CRT may be explained by the presence of scar tissue in the posterolateral left ventricular (LV) segments, which may result in ineffective LV pacing and inadequate LV resynchronization. In the present study, the relationship between transmural posterolateral scar tissue and response to CRT was evaluated. METHODS AND RESULTS: Forty consecutive patients with end-stage heart failure (NYHA class III/IV), LV ejection fraction < or =35%, QRS duration >120 ms, left bundle-branch block, and chronic coronary artery disease were included. The localization and transmurality of scar tissue were evaluated with contrast-enhanced MRI. Next, LV dyssynchrony was assessed at baseline and immediately after implantation with tissue Doppler imaging. Clinical parameters, LV volumes, and LV ejection fraction were assessed at baseline and at a 6-month follow-up. Fourteen patients (35%) had a transmural (>50% of LV wall thickness) posterolateral scar. In contrast to patients without posterolateral scar tissue, these patients showed a low response rate (14% versus 81%; P<0.05) and did not show improvement in clinical or echocardiographic parameters. In addition, LV dyssynchrony remained unchanged after CRT implantation (84+/-46 versus 78+/-41 ms; P=NS). Patients without posterolateral scar tissue and severe baseline dyssynchrony (> or =65 ms) showed an excellent response rate of 95% compared with patients with a posterolateral scar and/or absent LV dyssynchrony (11%). CONCLUSIONS: CRT does not reduce LV dyssynchrony in patients with transmural scar tissue in the posterolateral LV segments, resulting in clinical and echocardiographic nonresponse to CRT.

Aged↗

PubMed2006

Meta-analysis of comparative diagnostic performance of magnetic resonance imaging and multislice computed tomography for noninvasive coronary angiography.

BACKGROUND: Magnetic resonance imaging (MRI) and multislice computed tomography (MSCT) have emerged as potential noninvasive coronary imaging techniques. The objective of the present study was to clarify the current accuracy of both modalities in the detection of significant coronary artery lesions (compared to conventional angiography as the gold standard) by means of a comprehensive meta-analysis of the presently available literature. METHODS: A total of 51 studies on the detection of significant coronary artery stenoses (> or = 50% diameter stenosis) and comparing results with conventional angiography were identified by means of a MEDLINE search. Weighted sensitivities, specificities, and predictive values, all with 95% CIs, as well as summary odds ratios, were calculated for both techniques. In addition, the relationship between diagnostic specificity and disease prevalence was determined using metaregression analysis. RESULTS: A comparison of sensitivities and specificities revealed significantly higher values for MSCT (weighted average 85% [95% CI 86%-88%] and 95% [95% CI 95%]) as compared with MRI (weighted average 72%, 95% CI 69%-75% and 87%, 95% CI 86%-88%). A significantly higher odds ratio (16.9-fold) for the presence of significant stenosis was observed for MSCT as compared with MRI (6.4-fold) (P < .0001). Linear regression analysis revealed a better specificity for MSCT versus MRI in lower disease prevalence populations (P = .056). CONCLUSION: Meta-analysis of the available studies with MRI and MSCT for noninvasive coronary angiography indicates that MSCT has currently a significantly higher accuracy to detect or exclude significant coronary artery disease.

Coronary Angiography↗

PubMed2006

Assessment of global and regional left ventricular function and volumes with 64-slice MSCT: a comparison with 2D echocardiography.

BACKGROUND: In patients with coronary artery disease (CAD), LV function and volumes are important parameters for long-term prognosis. Multislice computed tomography (MSCT) allows noninvasive assessment of the coronary arteries, but the accuracy of 64-slice MSCT for the assessment of left ventricular (LV) volumes and function is unknown. METHODS AND RESULTS: A head-to-head comparison between 64-slice MSCT and 2-dimensional (2D) echocardiography was performed in 40 patients with known or suspected CAD. The LV end-diastolic volume (LVEDV) and LV end-systolic volume (LVESV) were determined and the LV ejection fraction (LVEF) was derived. Regional wall motion was assessed visually using a 17-segment model. A 3-point scoring system was used to assign to each segment a wall motion score: 1 = normokinesia, 2 = hypokinesia, 3 = akinesia or dyskinesia. Two-dimensional echocardiography served as the gold standard. MSCT agreed well with 2D echocardiography for assessment of LVEDV (r = 0.97; p < .0001) and LVESV (r = 0.98; p < .0001). An excellent correlation between MSCT and 2D echocardiography was shown for the evaluation of LVEF (r = 0.91; p < .0001). Agreement for the assessment of regional wall motion was excellent (96%, kappa = 0.82). CONCLUSIONS: An accurate assessment of global and regional LV function and volumes is feasible with 64-slice MSCT.

Coronary Artery Disease↗

PubMed2006

Do risk factors influence the diagnostic accuracy of noninvasive coronary angiography with multislice computed tomography?

BACKGROUND: Multislice computed tomography (MSCT) is a relatively new noninvasive imaging modality in the evaluation of patients with suspected coronary artery disease (CAD). Whether diagnostic accuracy is influenced by gender or risk factors for CAD is currently unknown and was evaluated in this study. METHODS AND RESULTS: In 197 patients (171 men and 26 women; mean age, 60 +/- 11 years) 16-slice MSCT was performed and compared with invasive coronary angiography at 2 different centers (Leiden and Rotterdam, The Netherlands). Diagnostic accuracy for the detection of 50% luminal narrowing or greater was calculated for all patients combined, as well as for patients with known versus suspected CAD. In addition, diagnostic accuracy was determined in men versus women and in different subsets of patients based on the presence of risk factors for CAD including hypertension, type 2 diabetes mellitus, hypercholesterolemia, and obesity. Only segments with a diameter of 2.0 mm or greater were evaluated, whereas smaller segments and stents were excluded from the analysis. Overall, a sensitivity and specificity of 99% and 86%, respectively, on a patient level were demonstrated, with corresponding positive and negative predictive values of 95% and 96%, respectively. Similar values were observed in the different subsets of patients, with no statistical differences. CONCLUSION: These findings confirm the high diagnostic accuracy of MSCT, regardless of gender or risk factors.

Aged↗

PubMed2005

Intraatrial repair of transposition of the great arteries: use of MR imaging after exercise to evaluate regional systemic right ventricular function.

PURPOSE: To prospectively assess regional systemic right ventricular (RV) function at rest and in response to exercise by using magnetic resonance (MR) imaging in patients who have undergone surgical correction at the atrial level for transposition of the great arteries (TGA). MATERIALS AND METHODS: Informed consent was obtained, and the medical review board approved this study. In 25 adult patients (mean age, 25.8 years +/- 4.7 [standard deviation]; 13 men) who had undergone correction for TGA (23.4 years +/- 4.9 after surgery) and 11 healthy volunteers (mean age, 27.4 years +/- 2.7; six men), systemic ventricular function was assessed with MR imaging (turbo field echo-planar imaging) at rest and during supine bicycle exercise. Regional wall thickness and wall thickening of the systemic RV were assessed and compared with those of the left ventricle in healthy volunteers by two investigators working together. Regional wall parameters were calculated by using the three-dimensional centerline method. Independent-samples t test and paired-samples t test were used for statistical analysis. RESULTS: Ejection fraction of the systemic RV did not increase after exercise (56% +/- 8 at rest to 55% +/- 7 after exercise, P = .196). Mean RV wall thickening was impaired in patients with TGA at all levels both at rest and in response to exercise (P < .05). Moreover, the free wall and the anterior wall of the systemic RV had a smaller end-systolic thickness and a diminished thickening at rest and after exercise compared with findings in the normal left ventricle (P < .05). CONCLUSION: The systemic RV of patients after intraatrial correction for TGA reveals regional functional disturbances at rest and in response to exercise.

Adult↗

PubMed2005

Time course of diastolic and systolic function improvement after pulmonary valve replacement in adult patients with tetralogy of Fallot.

OBJECTIVES: The aim of this research was to assess right ventricular diastolic and systolic function before and after pulmonary valve replacement (PVR) in adult patients after repair of tetralogy of Fallot. BACKGROUND: Pulmonary valve replacement (PVR) in adult patients late after repair of tetralogy of Fallot leads to rapid improvement of right ventricular (RV) systolic function. METHODS: A total of 16 patients and 8 healthy subjects were included. Median age at initial repair was 4.9 (0.9 to 13.1) years, and mean age at PVR was 28.7 (19.5 to 45.6) years. Cardiac magnetic resonance imaging was performed before and 8 and 22 months after PVR. Right ventricular volumes and function as well as RV in- and outflow patterns were assessed. RESULTS: The volume of the early filling of the RV (Evol) increased from 49.8 +/- 14.7 ml to 53.8 +/- 19.3 ml (not significant) and 62.0 +/- 18.9 ml, respectively (p < 0.05), whereas the volume of the atrial contraction (Avol) remained unchanged. Consequently, the Evol/Avol ratio increased from 1.4 +/- 0.7 before PVR to 1.6 +/- 0.7 at 8 months (not significant) and 2.3 +/- 1.2 at 22 months (p < 0.01). The Evol/Avol ratio was not significantly different from the healthy subjects at 22 months, indicating late recovery of diastolic function. Systolic function improved rapidly after PVR; the indexed RV end-systolic volume decreased from 93.7 +/- 33.0 ml/m2 to 60.9 +/- 18.4 ml/m2 (p < 0.01) and 54.8 +/- 21.0 ml/m2 (p < 0.01). CONCLUSIONS: In adult patients late after total repair of Fallot, PVR leads to late improvement of diastolic function. We speculate that the rapid volume unloading after PVR increases systolic performance, whereas improvement in diastolic function requires long-term remodeling.

Adolescent↗

PubMed2005

MRI to evaluate left atrial and ventricular reverse remodeling after restrictive mitral annuloplasty in dilated cardiomyopathy.

BACKGROUND: Data on reverse remodeling of the left atrium (LA) and left ventricle (LV) after restrictive annuloplasty in patients with dilated cardiomyopathy are scarce, and follow-up studies are performed with echocardiography. METHODS AND RESULTS: Twenty patients with dilated cardiomyopathy and severe mitral regurgitation selected for restrictive mitral annuloplasty underwent serial MRI studies (within 1 week before surgery, and 2 months [n =18] and 1 year [n =13] after surgery). Early mortality was 10%; all patients were free from endocarditis and thromboembolism. New York Heart Association class improved from 3.2+/-0.4 to 1.2+/-0.9. Only 1 patient developed recurrent severe mitral regurgitation during follow-up and it was re-repaired. LA end-systolic volumes decreased significantly over time (from 165+/-48 mL to 109+/-23 mL to 111+/-28 mL; P < 0.01), as did LA end-diastolic volumes (from 92+/-32 mL to 71+/-22 mL to 75+/-17 mL; P = 0.01). LV end-diastolic volumes decreased significantly (from 244+/-56 mL to 184+/-54 mL to 195+/-67 mL; P < 0.01), whereas end-systolic volumes did not change significantly. LV ejection fraction increased significantly (from 35+/-8% to 46+/-13% to 46+/-15%; P < 0.01) and LV mass decreased significantly (from 150+/-43 grams to 132+/-39 grams to 136+/-33 grams; P = 0.02). CONCLUSIONS: Restrictive annuloplasty in patients with dilated cardiomyopathy yielded excellent clinical results associated with significant LA and LV reverse remodeling over time as demonstrated by MRI.

Adult↗

PubMed2005

Global and regional left ventricular function assessment with 16-detector row CT: comparison with echocardiography and cardiovascular magnetic resonance.

AIMS: To compare multidetector row computed tomography (MDCT) global and regional left ventricular (LV) function assessment with echocardiography and cardiovascular magnetic resonance (CMR). METHODS AND RESULTS: In 25 patients, who were referred for noninvasive angiography with 16-detector row CT, LV function assessment was also performed. A subsequent echocardiogram was performed, and in a subgroup of patients, CMR examination was completed to evaluate LV function. For global function assessment, the LV ejection fraction (LVEF) was calculated. Regional LV function was scored using a 17-segment model and a 4-point scoring system. MDCT agreed well with echocardiography for the assessment of LVEF (r=0.96; bias 0.54%; p<0.0001) and regional LV function (kappa=0.78). Eight patients had no contra-indications and gave informed consent for CMR examination. A fair correlation between MDCT and CMR was demonstrated in the assessment of LVEF (r=0.86; bias -1.5%; p<0.01). Regional LV function agreement between MDCT and CMR was good (kappa=0.86). CONCLUSION: MDCT agreed well with both echocardiography and CMR in the assessment of global and regional LV function. Global and regional LV function may accurately be evaluated by 16-detector row CT, and can be added to a routine CT image analysis protocol without need for additional contrast or imaging time.

Aged↗

PubMed2005

Which parameters on magnetic resonance imaging determine Q waves on the electrocardiogram?

Studies have demonstrated that patients with Q-wave infarctions on the electrocardiogram (ECG) frequently have nontransmural scar formation, whereas non-Q-wave infarctions may have transmural scars. The precise pathophysiologic substrate that underlies Q waves remains unclear. Magnetic resonance imaging (MRI) is the preferred technique to evaluate patients who have infarction because information can be obtained on function, contractile reserve (viability), and scar tissue. Consecutive patients (n = 69) who had coronary artery disease and a history of myocardial infarction underwent MRI; the protocol included MRI at rest, small-dose dobutamine MRI, and contrast-enhanced MRI. Parameters included left ventricular ejection fraction, left ventricular volumes, end-diastolic wall thickness and contractile reserve in the infarct region, transmurality and spatial extent of scar tissue, total scar score, and quantified percent left ventricular scar tissue. MRI data were related to the presence/absence of Q waves on the ECG. Q waves were present in 39 patients (57%). Univariate analysis identified transmurality, spatial extent, total scar score, and quantified percent scar tissue as predictors of Q waves. Multivariate analysis demonstrated that quantified percent scar tissue was the single best predictor of Q waves on the ECG. A cut-off value of 17% infarcted tissue of the left ventricle yielded a sensitivity and specificity of 90% to predict the presence/absence of Q waves. When quantified percent scar tissue was removed from the model, spatial extent of infarction was the best predictor. Thus, Q waves on the ECG correlate best with quantified percent scar tissue on contrast-enhanced MR images.

Aged↗

PubMed2005

Feasibility of tissue magnetic resonance imaging: a pilot study in comparison with tissue Doppler imaging and invasive measurement.

OBJECTIVES: This research was intended to determine the feasibility of tissue magnetic resonance (MR) imaging in comparison with tissue Doppler imaging and its potential implications for the estimation of filling pressure, in comparison with invasive measurement. BACKGROUND: Evaluation of diastolic function using MR imaging is commonly confined to the study of transmitral flow. However, transmitral flow is unreliable for the estimation of left ventricular (LV) filling pressures in hypertrophy and normal systolic function. Normalizing early mitral velocity (E) for the influence of myocardial relaxation by combining E with early diastolic mitral septal tissue velocity (Ea) provides better Doppler estimates of filling pressures. METHODS: Eighteen patients with hypertensive heart disease (LV mass index: 114 +/- 21 g/m(2)), absence of valvular regurgitation, and with normal or mildly reduced systolic function (LV ejection fraction: 57.6 +/- 6.5%) referred for cardiac catheterization, underwent consecutive measurement of mitral flow and septal tissue velocities with phase-contrast MR and Doppler. These data were compared with mean pulmonary capillary wedge pressure (PCWP). RESULTS: There was a strong relation between MR (11.6 +/- 4.3) and Doppler-assessed (12.1 +/- 3.5) E/Ea (95% confidence interval of -1.5 to 0.5) (r = 0.89, p < 0.0001). In addition, E/Ea related strongly to invasively measured PCWP (MR: r = 0.80, p < 0.0001 and Doppler: r = 0.85, p < 0.0001). CONCLUSIONS: Tissue MR imaging is a feasible method to assess Ea. Combining E and Ea allowed similar estimation of filling pressure by MR and Doppler, in good agreement with invasive measurement. The potential confounding effect of valvular regurgitation needs further study.

Blood Flow Velocity↗

PubMed2005

Noninvasive coronary imaging and assessment of left ventricular function using 16-slice computed tomography.

In recent years, multislice computed tomography (MSCT) has been demonstrated to be a feasible imaging modality for noninvasive coronary angiography and left ventricular function analysis. The present study evaluated overall performance of 16-slice MSCT in the detection of significant coronary artery disease, stent, or bypass graft stenosis in combination with global left ventricular function analysis. Forty-five patients underwent 16-slice MSCT. Multislice computed tomograms were used to evaluate the presence of significant coronary artery stenoses (>/=50% decrease in luminal diameter) in native coronary segments, bypass grafts, and coronary stents and were compared with conventional coronary angiograms. In addition, left ventricular ejection fraction was calculated and compared with 2-dimensional echocardiography. MSCT was performed successfully in all patients. A close correlation between MSCT and 2-dimensional echocardiography was demonstrated for the assessment of left ventricular ejection fraction (y = 0.93x +3.33, r = 0.96, p <0.001). A total of 298 of native coronary artery segments (94%) were evaluated with MSCT, whereas 81 of 94 grafts (85%) and 41 of 52 coronary stents (79%) were also evaluated. For all segments, overall sensitivity, specificity, and positive and negative predictive values were 85%, 89%, 71%, and 95%, respectively. In conclusion, 16-slice MSCT is a feasible modality for noninvasive evaluation and exclusion of coronary artery disease in patients who present with chest pain.

Contrast Media↗