Late cardiac remodeling after primary percutaneous coronary intervention-five-year cardiac magnetic resonance imaging follow-up.

BACKGROUND: Primary percutaneous coronary intervention (PPCI) preserves function and improves survival. The late effects of PPCI on left ventricular remodeling, however, have not yet been investigated on cardiac magnetic resonance imaging (CMRI). METHODS AND RESULTS: Twenty-five patients with acute myocardial infarction (AMI) treated with PPCI underwent CMRI within 10 days, at 4 months and at 5 years. Left ventricular ejection fraction (LVEF), end-diastolic volume (EDV) and end-systolic volume were quantified on cine images. Infarct mass and transmural extent of infarction were quantified on contrast-enhanced imaging. In all patients EDV increased significantly in the early phase (192 ± 40 ml to 211 ± 49 ml, P ≤ 0.01) and LVEF improved significantly (42 ± 9% to 46 ± 9%, P=0.02). In the late phase (>4 months) no significant changes were observed (LVEF 44 ± 9%, P=0.07; EDV 216 ± 68 ml, P=0.38). Three different groups could be identified. One-third (32%) had no dilatation at all; one-third (32%) had limited dilatation at 4 months without progression later; and 36% had progressive dilatation both at 4 months and at late follow-up. This third group had an average increase in EDV of 20% in the acute phase followed by an additional 13%. The strongest predictor for progressive dilatation was infarct mass. CONCLUSIONS: Even in the era of PPCI for AMI followed by optimal medical therapy, one-third of patients had progressive dilatation, which was best predicted by infarct mass.

Evaluation of left ventricular function three years after percutaneous recanalization of chronic total coronary occlusions.

We investigated early and late effects of percutaneous revascularization for chronic total coronary occlusion on left ventricular (LV) function and volumes. Magnetic resonance imaging was performed in 21 patients before and 5 months and 3 years after recanalization. Global LV function and volumes and segmental wall thickening (SWT) were quantified on cine images. The 2 viability indexes used were the transmural extent of infarction (TEI) on delayed contrast enhancement images and end-diastolic wall thickness at baseline. Significant decreases in mean end-diastolic (86 +/- 14 to 78 +/- 15 ml/m2; p = 0.02) and mean end-systolic volume indexes (35 +/- 13 to 30 +/- 13 ml/m2; p = 0.03) were observed 3 years after recanalization. Mean ejection fraction tended to improve (60 +/- 9% to 63 +/- 11%; p = 0.11). SWT significantly increased at 5-months' follow-up (p <0.001), and an additional improvement was found at 3 years' (p = 0.04) follow-up in segments with TEI <25%. In segments with TEI of 25% to 75%, SWT was unchanged at 5-month follow-up (p = 0.89), but improved at 3 years (p = 0.04). SWT was unchanged in segments with transmural scars. For segmental functional recovery, TEI was a better predictor than end-diastolic wall thickness at baseline (odds ratio 5.6, 95% confidence interval 1.5 to 21.1, p = 0.01 vs odds ratio 2.5, 95% confidence interval 0.7 to 8.3, p = 0.14). In conclusion, a positive effect on LV remodeling and ejection fraction was observed up to 3 years after recanalization. Both early and late improvements in regional LV function were observed in the perfusion territory of chronic total coronary occlusion and were related to the transmural extent of infarction on pretreatment magnetic resonance imaging.

Addition of the long-axis information to short-axis contours reduces interstudy variability of left-ventricular analysis in cardiac magnetic resonance studies.

OBJECTIVES: To reduce interstudy variability using long-axis information for correcting short-axis (SA) contours at basal and apical level for left-ventricular analysis by magnetic resonance imaging. MATERIALS AND METHODS: A total of 20 patients with documented heart failure and 20 volunteers underwent magnetic resonance imaging examination twice for measuring endocardial end-diastolic volume, endocardial end-systolic volume, mass, and ejection fraction. The boundary of the left ventricle, the mitral valve plane, and apex were marked manually on the 2- and 4-chamber long-axis images. Automatic epicardial and endocardial contour detection was performed on the SA images using the intersection of the outlines from the long axis as starting positions. The same observer compared the interstudy variability of this method with analysis that was based on the SA images only. RESULTS: The interstudy variability decreased when information from the long axis was included; for end-systolic volume, 9.6% versus 4.7% (P = 0.00014); for end-diastolic volume, 4.9% versus 2.5% (P = 0.0011); for mass, 7.4% versus 5.0% (P = 0.11); and for ejection fraction 12.2% versus 5.6% (P = 0.0017), respectively. CONCLUSIONS: Identification of the mitral valve plane and apex on long-axis images to limit the extent of volume at the base and the apex of the heart reduces interstudy variability for left-ventricular functional assessment.

Assessment of acute reperfused myocardial infarction with delayed enhancement 64-MDCT.

OBJECTIVE: The purpose of this study was to evaluate the utility of delayed enhancement 64-MDCT in the assessment of myocardial infarct size in a porcine model of acute reperfused myocardial infarction. CT can be used for noninvasive assessment of coronary artery stenosis, but to our knowledge, evaluation of myocardial viability in the subacute phase of acute myocardial infarction has not been validated. We performed delayed enhancement imaging on six domestic swine 5 days after reperfused acute myocardial infarction and assessed the relation between delayed enhancement patterns in vivo and the extent of viable and nonviable myocardium at postmortem histochemical analysis. CONCLUSION: Delayed enhancement imaging with 64-MDCT can be used for accurate assessment of the size of reperfused acute myocardial infarcts.

High-resolution spiral computed tomography coronary angiography in patients referred for diagnostic conventional coronary angiography.

BACKGROUND: The diagnostic performance of the latest 64-slice CT scanner, with increased temporal (165 ms) and spatial (0.4 mm3) resolution, to detect significant stenoses in the clinically relevant coronary tree is unknown. METHODS AND RESULTS: We studied 52 patients (34 men; mean age, 59.6+/-12.1 years) with atypical chest pain, stable or unstable angina pectoris, or non-ST-segment elevation myocardial infarction scheduled for diagnostic conventional coronary angiography. All patients had stable sinus rhythm. Patients with initial heart rates > or =70 bpm received beta-blockers. Mean scan time was 13.3+/-0.9 seconds. The CT scans were analyzed by 2 observers unaware of the results of invasive coronary angiography, which was used as the standard of reference. All available coronary segments, regardless of size, were included in the evaluation. Lesions with > or =50 luminal narrowing were considered significant stenoses. Invasive coronary angiography demonstrated the absence of significant disease in 25% (13 of 52), single-vessel disease in 31% (16 of 52), and multivessel disease in 45% (23 of 52) of patients. One unsuccessful CT scan was classified as inconclusive. Ninety-four significant stenoses were present in the remaining 51 patients. Sensitivity, specificity, and positive and negative predictive values of CT for detecting significant stenoses on a segment-by-segment analysis were 99% (93 of 94; 95% CI, 94 to 99), 95% (601 of 631; 95% CI, 93 to 96), 76% (93 of 123; 95% CI, 67 to 89), and 99% (601 of 602; 95% CI, 99 to 100), respectively. CONCLUSIONS: Noninvasive 64-slice CT coronary angiography accurately detects coronary stenoses in patients in sinus rhythm and presenting with atypical chest pain, stable or unstable angina, or non-ST-segment elevation myocardial infarction.

Comparison between contrast echocardiography and magnetic resonance imaging to predict improvement of myocardial function after primary coronary intervention.

The relative merits of myocardial contrast echocardiography (MCE) and magnetic resonance imaging (MRI) to predict myocardial function improvement after percutaneous coronary intervention have not been evaluated until now. We studied 35 consecutive patients with acute myocardial infarction who underwent percutaneous coronary intervention using MCE and MRI and first-pass imaging for evaluation of myocardial perfusion. Delayed-enhanced MRI was included as another method to differentiate viable from infarcted tissue. MCE was performed by power modulation and intravenous Sonovue. A 16-segment model of the left ventricle was used to analyze all myocardial contrast echocardiograms and magnetic resonance images. At 60 days of follow-up, MCE showed improvement of function in 115 of 192 (60%) dysfunctional segments. The sensitivity, specificity, and accuracy for the prediction of functional improvement were comparable among MCE (87%, 90%, and 88%), first-pass MRI (87%, 60%, and 79%), and delayed-enhancement MRI (75%, 100%, and 82%, respectively, all p = NS). In conclusion, MCE and MRI allowed for prediction of myocardial function improvement after percutaneous coronary intervention. MCE had a comparable accuracy and, as a bedside technique, may be an alternative tool in the acute phase of acute myocardial infarction.

Usefulness of multislice computed tomographic coronary angiography to assess in-stent restenosis.

Fifty-one patients (42 men; 60 +/- 12 years of age) who had previous stent implantation underwent multislice computed tomographic coronary angiography. All coronary branches > or = 2.0 mm were independently evaluated by 2 observers and screened for in-stent restenosis (> or = 50%) and occlusion. The consensus reading was compared with the quantitative coronary angiogram. Six of the 74 (8.1%) evaluated stents (3 restenoses and 3 occlusions) were significantly diseased. The sensitivity, specificity, and positive and negative predictive values to identify restenosis were 83.3% (95% confidence interval [CI] 35.9 to 99.6), 98.5% (95% CI 92.1 to 100), 83.3% (95% CI 35.9 to 99.6), and 97.3% (95% CI 92.1 to 100), respectively. One in-stent restenosis remained undetected.

Standard versus user-interactive assessment of significant coronary stenoses with multislice computed tomography coronary angiography.

Forty-four patients in sinus rhythm with suspected coronary artery disease underwent 16-row multislice computed tomography coronary angiography and conventional coronary angiography. Two protocols for image analysis were applied to the multislice computed tomographic images: standard projections versus interactive postprocessing. The diagnostic accuracy of both methods for the detection of significant lesions (>50% lumen reduction) was compared with quantitative coronary angiography. Sensitivity and specificity were 58% and 96% and 96% and 97%, for standard projections and interactive postprocessing protocol, respectively.

Computed tomography unmasks a phantom tumour.

We describe a patient with left sided congestive heart failure and a round-shaped mass on the chest X-ray. Using computed tomography, the mass is diagnosed as a phantom tumour consisting of loculated effusion in the interlobular fissure that vanishes after treatment for heart failure is initiated.

Different algorithms for quantitative analysis of myocardial infarction with DE MRI: comparison with autopsy specimen measurements.

RATIONALE AND OBJECTIVES: To compare two semiautomated methods for measurement of infarcted myocardium area on delayed contrast enhanced magnetic resonance imaging, with histopathology findings as standard of reference. MATERIALS AND METHODS: Percentage area of myocardial infarction was measured in 10 Yorkshire landrace pigs manually and using two semiautomated methods. The first (standard deviation method) used two operator-selected regions of interest (ROIs) and nine different cutoff values (one to nine times the standard deviation of signal intensity in normal myocardium) to identify infarction. The second (threshold method) used threshold values based on percentages of maximum signal intensity to identify infarction. Results were compared with histopathology findings. RESULTS: Difference between percentage area of infarction obtained with standard deviation method and autopsy specimens was in the range: -13.5% to +13.2%. With threshold method (thresholds from 30% to 90% of signal intensity), difference was -15% to +23%. Manual contouring underestimated infarcted area by 2% comparing to autopsy results. The best agreement between histopathology and semi-automated software was achieved for 4 standard deviations with standard deviation method: difference -0.45%, and for a percentage threshold of 70% (difference +0.67%) with threshold method. However, with standard deviation method, there was statistically significant difference between ROIs based on their location in viable myocardium: mean difference 1.7 ± 4%, P < .0001. CONCLUSION: Semiautomated measurement of myocardial infarcted area on delayed enhanced magnetic resonance images performs well compared to autopsy. The threshold method, based on percentages of maximum signal intensity is preferable over standard deviation method, which is more susceptible to variability from location of ROIs within viable myocardium.

Accurate automatic papillary muscle identification for quantitative left ventricle mass measurements in cardiac magnetic resonance imaging.

RATIONALE AND OBJECTIVES: We sought to evaluate the automatic detection of the papillary muscle and to determine its influence on quantitative left ventricular (LV) mass assessment. MATERIALS AND METHODS: Twenty-eight Yorkshire-Landrace swine and 10 volunteers underwent cardiac magnetic resonance imaging (CMR) of the left ventricle. The variability in measurements of LV papillary muscles traced automatically and manually were compared to intra- and interobserver variabilities. CMR-derived LV mass with the papillary muscle included or excluded from LV mass measurements was compared to true mass at autopsy of the Yorkshire-Landrace swine. RESULTS: Automatic LV papillary muscle mass from all subjects correlated well with manually derived LV papillary muscle mass measurements (r = 0.84) with no significant bias between both measurements (mean difference +/- SD, 0.0 +/- 1.5 g; P = .98). The variability in results related to the contour detection method used was not statistically significant different compared to intra- and interobserver variabilities (P = .08 and P = .97, respectively). LV mass measurements including the papillary muscle showed significantly less underestimation (-10.6 +/- 7.1 g) with the lowest percentage variability (6%) compared to measurements excluding the papillary muscles (mean underestimation, -15.1 +/- 7.4 g percentage variability, 7%). CONCLUSION: The automatic algorithm for detecting the papillary muscle was accurate with variabilities comparable to intra- and interobserver variabilities. LV mass is determined most accurately when the papillary muscles are included in the LV mass measurements. Taken together, these observations warrant the inclusion of automatic contour detection of papillary muscle mass in studies that involve the determination of LV mass.

Non-invasive visualization of coronary atherosclerosis: state-of-art.

Coronary artery disease remains the leading cause of death in the Western world. Non-invasive coronary artery imaging challenges any diagnostic modality because the coronary arteries are small and tortuous, whereas cardiac contraction and respiration cause motion artifacts. Therefore, non-invasive coronary imaging requires high spatial and temporal resolution. This review discusses the feasible applications in coronary imaging of magnetic resonance imaging and multi-slice computed tomography (MSCT), which are currently the only non-invasive diagnostic modalities for direct coronary atherosclerosis imaging. Particular attention and focus is devoted to the potential indications and clinical impact of MSCT due to its fast development and the robust results recently reported. MSCT of the coronary arteries is a promising imaging modality for the assessment of the coronary lumen and wall.

Adjunctive value of CT coronary angiography in the diagnostic work-up of patients with typical angina pectoris.

AIMS: To determine the adjunctive value of CT coronary angiography (CTCA) in the diagnostic work-up of patients with typical angina pectoris. METHODS AND RESULTS: CTCA was performed in 62 consecutive patients (45 male, mean age 58.8 +/- 7.7 years) with typical angina undergoing diagnostic work-up including exercise-ECG and conventional coronary angiography. Only patients with sinus heart rhythm and ability to breath hold for 20 s were included. Patients with initial heart rates >/=70 beats/min received beta-blockers. We determined the post-test likelihood ratios, to detect or exclude patients with significant (>/=50% lumen diameter reduction) stenoses, of exercise-ECG and CTCA separately, and of CT performed after exercise-ECG testing. The prevalence of patients with significant coronary artery disease (CAD) was 74%. Positive and negative likelihood ratios for exercise-ECG were 2.3 [95% confidence interval (CI): 1.0-5.3] and 0.3 (95% CI: 0.2-0.7) and for CTCA 7.5 (95% CI: 2.1-27.1) and 0.0 (95% CI: 0.0-8), respectively. CTCA increased the post-test probability of significant CAD after a negative exercise-ECG from 58 to 91%, and after a positive exercise-ECG from 89 to 99%, while CT correctly identified patients without CAD (probability 0%). CONCLUSION: Non-invasive CTCA is a potentially useful tool, in the diagnostic work-up of patients with typical angina pectoris, both to detect and to exclude significant CAD.

Intracoronary delivery of umbilical cord blood derived unrestricted somatic stem cells is not suitable to improve LV function after myocardial infarction in swine.

Regeneration of infarcted myocardium by injecting stem cells has been proposed to prevent heart failure. We studied the i.c. administration of human umbilical cord blood stem cells (USSC) in a porcine model of myocardial infarction (MI) and reperfusion. In 15 swine, MI was induced by balloon-occlusion of the left circumflex coronary artery (LCX) for 2 h followed by reperfusion. Five swine served as healthy controls. One week later, magnetic resonance imaging (MRI) was performed to assess left ventricular (LV) function and infarct size. Then, under immune suppression, 6 of the 12 surviving MI swine received intracoronary injection of approximately 10(8) human USSC in the LCX while the other MI-swine received medium. Four weeks later all swine underwent follow-up MRI, and were sacrificed for histology. One week after MI, end-diastolic volume (92+/-3 mL) and LV mass (75+/-2 g) were larger, while ejection fraction (42+/-2%) was smaller than in healthy control (68+/-3 mL, 66+/-3 g and 55+/-3%, all P<0.05). Regional wall thickening (-7+/-2%) in the LCX area became akinetic. No difference in global and regional LV function at 5 weeks was observed between MI animals receiving USSC or medium. Infarct size after USSC treatment was significantly larger (20+/-3 g vs. 8+/-2 g, P<0.05). USSC survived only in the infarct border zone at 5 weeks and did not express cardiomyocyte or endothelial markers. Histology showed that intracoronary injection of USSC caused micro infarctions by obstructing blood vessels. In swine with a 1 week old MI, injection of USSC via the intracoronary route does not improve LV function 4 weeks later.

A comparison between QLAB and TomTec full volume reconstruction for real time three-dimensional echocardiographic quantification of left ventricular volumes.

OBJECTIVES: To compare the interobserver variability and accuracy of two different real time three-dimensional echocardiography (RT3DE) analyzing programs. METHODS: Forty-one patients (mean age 56 +/- 11 years, 28 men) in sinus rhythm with a cardiomyopathy and adequate 2D image quality underwent RT3DE and magnetic resonance imaging (MRI) within one day. Off-line left ventricular (LV) volume analysis was performed with QLAB V4.2 (semiautomated border detection with biplane projections) and TomTec 4D LV analysis V2.0 (primarily manual tracking with triplane projections and semiautomated border detection). RESULTS: Excellent correlations (R(2) > 0.98) were found between MRI and RT3DE. Bland-Altman analysis revealed an underestimated LV end-diastolic volume (LV-EDV) for both TomTec (-9.4 +/- 8.7 mL) and QLAB (-16.4 +/- 13.1 ml). Also, an underestimated LV end-systolic volume (LV-ESV) for both TomTec (-4.8 +/- 9.9 mL) and QLAB (-8.5 +/- 14.2 mL) was found. LV-EDV and LV-ESV were significantly more underestimated with QLAB software. Both programs accurately calculated LV ejection fraction (LV-EF) without a bias. Interobserver variability was 6.4 +/- 7.8% vs. 12.2 +/- 10.1% for LV-EDV, 7.8 +/- 9.7% vs. 13.6 +/- 11.2% for LV-ESV, and 7.1 +/- 6.9% vs. 9.7 +/- 8.8% for LV-EF for TomTec vs. QLAB, respectively. The analysis time was shorter with QLAB (4 +/- 2 minutes vs. 6 +/- 2 minutes, P < 0.05). CONCLUSIONS: RT3DE with TomTec or QLAB software analysis provides accurate LV-EF assessment in cardiomyopathic patients with distorted LV geometry and adequate 2D image quality. However, LV volumes may be somewhat more underestimated with the current QLAB software version.

Chronic pseudoaneurysm of the left ventricle.

We present a case of a 55-year-old men who suffered a silent myocardial infarction four years earlier and presented with exertional dyspnoea. Cardiac magnetic resonance imaging (CMR) and Multislice computed tomography (MSCT) was performed and revealed a giant pseudoaneursym of the lateral wall of the left ventricle with the presence of a thrombus in the lateral wall of the pseudoaneursym. We present this case since excellent non-invasive evaluation of the pseudoaneursym was feasible using state-of-the-art imaging modalities. Information on left ventricular geometry and function as well as myocardial viability and coronary anatomy is available when both MSCT and CMR are performed. This combined approach of these two imaging modalities provide clinically relevant information and may guide therapeutic decision making.

Diagnostic accuracy of non-invasive 64-slice CT coronary angiography in patients with stable angina pectoris.

Multislice computed tomography (CT) is an emerging technique for the non-invasive detection of coronary stenoses. While the diagnostic accuracy of 4-slice scanners was limited, 16-slice CT imagers showed promising results due to increased temporal and spatial resolution. These technical advances prompted us to evaluate the diagnostic performance of 64-slice CT coronary angiography in the detection of significant stenoses (defined as > or = 50% luminal diameter reduction) versus invasive quantitative coronary angiography (QCA). Thirty-five patients with stable angina pectoris underwent CT coronary angiography performed with a 64-slice scanner (gantry rotation time 330 ms, individual detector width 0.6 mm) prior to conventional coronary angiography. Patients with heart rates >70 beats/min received 100 mg metoprolol orally. One hundred millilitres of contrast agent with an iodine concentration of 400 mgl/ml were injected at a rate of 5 ml/s into the antecubital vein. The CT scan was triggered with the bolus tracking technique. The sensitivity, specificity and the positive and negative predictive values of 64-slice CT were 99%, 96%, 78% and 99%, respectively, on a per-segment basis. The values obtained on a per-patient basis were 100%, 90%, 96% and 100%, respectively. When referral to catheterisation is questionable, CT coronary angiography may identify subjects with normal angiograms and consistently decrease the number of unnecessary invasive procedures.

Multislice computed tomography and magnetic resonance imaging for the assessment of reperfused acute myocardial infarction.

OBJECTIVES: We evaluated the accuracy of in vivo delayed-enhancement multislice computed tomography (DE-MSCT) and delayed-enhancement magnetic resonance imaging (DE-MRI) for the assessment of myocardial infarct size using postmortem triphenyltetrazolium chloride (TTC) pathology as standard of reference. BACKGROUND: The diagnostic value of DE-MSCT for the assessment of acute reperfused myocardial infarction is currently unclear. METHODS: In 10 domestic pigs (25 to 30 kg), the circumflex coronary artery was balloon-occluded for 2 h followed by reperfusion. After 5 days (3 to 7 days), DE-MRI (1.5-T) was performed 15 min after administration of 0.2 mmol/kg gadolinium-DTPA using an inversion recovery gradient echo technique. On the same day, DE-MSCT (64-slice) was performed 15 min after administration of 1 gI/kg of iodinated contrast material. One day after imaging, hearts were excised, sectioned in 8 mm short-axis slices, and stained with TTC. Infarct size was defined as the hyperenhanced area on DE-MSCT and DE-MRI images and the TTC-negative area on TTC pathology slices. Infarct size was expressed as percentage of total slice area. RESULTS: Infarct size determined by DE-MSCT and DE-MRI showed a good correlation with infarct size assessed with TTC pathology (R2 = 0.96 [p < 0.001] and R(2) = 0.93 [p < 0.001], respectively). The correlation between DE-MSCT and DE-MRI was also good (R2 = 0.96; p < 0.001). The relative difference in CT attenuation value of infarcted myocardium compared to remote myocardium was 191 +/- 18%. The relative MR signal intensity between infarcted myocardium and remote myocardium was 554 +/- 156%. CONCLUSIONS: We demonstrated that DE-MSCT can assess acute reperfused myocardial infarction in good agreement with in vivo DE-MRI and TTC pathology.