Delayed Enhancement Research Articles

Effect of manual thrombus aspiration during primary percutaneous coronary intervention on infarct size: Evaluation with cardiac computed tomography

Thrombus aspiration during percutaneous coronary intervention (PCI) for acute myocardial infarction (MI) may improve myocardial reperfusion. In the present study, we sought to assess whether manual thrombus aspiration could reduce infarct size in patients with acute ST-elevation MI undergoing primary PCI utilizing cardiac computed tomography (CCT) on a delayed enhancement (DE) scanning (DE-CCT).

Inverse Relationship Between Fractionated Electrograms and Atrial Fibrosis in Persistent Atrial Fibrillation: Combined Magnetic Resonance Imaging and High-Density Mapping

This study sought to evaluate the relationship between fibrosis imaged by delayed-enhancement (DE) magnetic resonance imaging (MRI) and atrial electrograms (Egms) in persistent atrial fibrillation (AF). Atrial fractionated Egms are strongly related to slow anisotropic conduction. Their relationship to atrial fibrosis has not yet been investigated. Atrial high-resolution MRI of 18 patients with persistent AF (11 long-lasting persistent AF) was registered with mapping geometry (NavX electro-anatomical system (version 8.0, St. Jude Medical, St. Paul, Minnesota)). DE areas were categorized as dense or patchy, depending on their DE content. Left atrial Egms during AF were acquired using a high-density, 20-pole catheter (514 ± 77 sites/map). Fractionation, organization/regularity, local mean cycle length (CL), and voltage were analyzed with regard to DE. Patients with long-lasting persistent versus persistent AF had larger left atrial (LA) surface area (134 ± 38 cm(2) vs. 98 ± 9 cm(2), p = 0.02), a higher amount of atrial DE (70 ± 16 cm(2) vs. 49 ± 10 cm(2), p = 0.01), more complex fractionated atrial Egm (CFAE) extent (54 ± 16 cm(2) vs. 28 ± 15 cm(2), p = 0.02), and a shorter baseline AF CL (147 ± 10 ms vs. 182 ± 14 ms, p = 0.01). Continuous CFAE (CFEmean [NavX algorithm that quantifies Egm fractionation] <80 ms) occupied 38 ± 19% of total LA surface area. Dense DE was detected at the left posterior left atrium. In contrast, the right posterior left atrium contained predominantly patchy DE. Most CFAE (48 ± 14%) occurred at non-DE LA sites, followed by 41 ± 12% CFAE at patchy DE and 11 ± 6% at dense DE regions (p = 0.005 and p = 0.008, respectively); 19 ± 6% CFAE sites occurred at border zones of dense DE. Egms were less fractionated, with longer CL and lower voltage at dense DE versus non-DE regions: CFEmean: 97 ms versus 76 ms, p < 0.0001; local CL: 153 ms versus 143 ms, p < 0.0001; mean voltage: 0.63 mV versus 0.86 mV, p < 0.0001. Atrial fibrosis as defined by DE MRI is associated with slower and more organized electrical activity but with lower voltage than healthy atrial areas. Ninety percent of continuous CFAE sites occur at non-DE and patchy DE LA sites. These findings are important when choosing the ablation strategy in persistent AF.

CMR imaging for the evaluation of myocardial stunning after acute myocardial infarction: a meta-analysis of prospective trials

Myocardial stunning is an important sequela of acute coronary syndromes and its determination might affect decisions on defibrillator implantation and assist devices after myocardial infarction (AMI). The aim of the study was to evaluate and compare the sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of cardiac magnetic resonance imaging (CMR) assessing myocardial stunning after acute myocardial infarction using low-dose dobutamine (LDD), end-diastolic wall thickness, and contrast delayed enhancement (DE). A systematic review of Medline, Embase, and Cochrane for all prospective trials assessing myocardial stunning by CMR following AMI was performed using a standard approach for meta-analysis for diagnostic test and a bivariate analysis. Search results revealed 9384 studies, out of which 17 met criteria. A total of 634 patients (mean age 59 years, 85% male, mean left ventricular ejection fraction: 52%) were included. DE-CMR had a weighted sensitivity of 87% and specificity of 68% to detect myocardial stunning using 50% transmurality as a cut-off, with a PPV and NPV of 83 and 72%, respectively. With an overall diagnostic accuracy of 82%, LDD-CMR had a sensitivity of 67% and a specificity of 81%, with a PPV and NPV of 82 and 63%, respectively. LDD showed an overall accuracy of 74%. DE-CMR has a higher sensitivity, whereas LDD-CMR has a higher specificity for the detection of viable stunned myocardium following myocardial infarction. Whether the combination of DE and LDD may improve the prediction of myocardial recovery remains to be determined.

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Left Ventricular Stroke Volume Quantification by Contrast Echocardiography – Comparison of Linear and Flow‐Based Methods to Cardiac Magnetic Resonance

Echocardiography (echo)-quantified LV stroke volume (SV) is widely used to assess systolic performance after acute myocardial infarction (AMI). This study compared 2 common echo approaches - predicated on flow (Doppler) and linear chamber dimensions (Teichholz) - to volumetric SV and global infarct parameters quantified by cardiac magnetic resonance (CMR). Multimodality imaging was performed as part of a post-AMI registry. For echo, SV was measured by Doppler and Teichholz methods. Cine-CMR was used for volumetric SV and LVEF quantification, and delayed-enhancement (DE) CMR for infarct size. Overall, 142 patients underwent same day echo and CMR. On echo, mean SV by Teichholz (78±17mL) was slightly higher than Doppler (75±16mL; Δ=3±13mL; P=0.02). Compared to SV on CMR (78±18mL), mean difference by Teichholz (Δ=-0.2±14; P=0.89) was slightly smaller than Doppler (Δ=-3±14; P=0.02), but limits of agreement were similar between CMR and echo methods (Teichholz: -28, 27mL, Doppler: -31, 24mL). For Teichholz, differences with CMR SV were greatest among patients with anteroseptal or lateral wall hypokinesis (P<0.05). For Doppler, differences were associated with aortic valve abnormalities or root dilation (P=0.01). SV by both echo methods decreased stepwise in relation to global LV injury as assessed by CMR-quantified LVEF and infarct size (P<0.01). Teichholz and Doppler calculated SV yield similar magnitude of agreement with CMR. Teichholz differences with CMR increase with septal or lateral wall contractile dysfunction, whereas Doppler yields increased offsets in patients with aortic remodeling.

MRI-GUIDED APPROACH TO LOCALIZE AND ABLATE GAPS IN REPEATED ATRIAL FIBRILLATION ABLATION PROCEDURE: A PILOT STUDY

The presence of gaps in prior pulmonary vein (PV) isolation (PVI) ablation lesions may be the cause of procedural failure. Delayed-enhanced (DE) cardiac magnetic resonance (CMR) allows the identification of radiofrequency (RF) lesions and gaps (CMR gaps). The present study aimed to test the

Relationship of Delayed Enhancement by Magnetic Resonance to Myocardial Perfusion by Positron Emission Tomography in Hypertrophic Cardiomyopathy

Presence of delayed enhancement (DE) on cardiac magnetic resonance (CMR) is associated with worse clinical outcomes in hypertrophic cardiomyopathy. We investigated the relationship between DE on CMR and myocardial ischemia in hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy patients (n=47) underwent CMR for assessment of DE and vasodilator stress ammonia positron emission tomography to quantify myocardial blood flow and coronary flow reserve. The summed difference score for regional myocardial perfusion was also assessed. Patients in the DE group (n=35) had greater left ventricular wall thickness (2.09±0.44 versus 1.78±0.34 cm; P=0.03). Stress myocardial blood flow (2.25±0.46 versus 1.78±0.43 mL/min per gram; P=0.01) and coronary flow reserve (2.78±0.32 versus 2.01±0.52; P<0.001) were significantly lower in DE-positive patients. Summed difference score (7.3±6.6 versus 0.9±1.4; P<0.0001) was significantly higher in patients with DE. A coronary flow reserve <2.00 was seen in 18 patients (51%) with DE but in none of the DE-negative patients (P<0.0001). CMR and positron emission tomography showed visually concordant DE and regional myocardial perfusion abnormalities in 31 patients and absence of DE and perfusion defects in 9 patients. Four DE-positive patients demonstrated normal regional myocardial perfusion, and 3 DE-negative patients had (apical) regional myocardial perfusion abnormalities. We found a close relationship between DE by CMR and microvascular function in most of the patients studied. However, a small proportion of patients had DE in the absence of perfusion abnormalities, suggesting that microvascular dysfunction and ischemia are not the sole causes of DE in hypertrophic cardiomyopathy patients.

The detection of left ventricular scar by delayed enhancement-CMR in non-ischemic cardiomyopathy is a stronger predictor of cardiovascular events than left ventricular ejection fraction

Background Left ventricular ejection fraction (LVEF) is a strong predictor of subsequent cardiovascular events in patients with ischemic and non-ischemic cardiomyopathy. CMR is an excellent technique for assessment of LVEF as well as for the detection of myocardial scar. We sought to evaluate if the presence of myocardial scarring in nonischemic cardiomyopathy could be an important predictor of cardiovascular events. Methods Inclusion criteria were absence of coronary artery disease, a diagnosis of cardiomyopathy and an LVEF ≤ 45%. Patients with a diagnosis of infiltrative disorders, hypertrophic cardiomyopathy, or tachycardia-induced cardiomyopathy were excluded. A total of 132 patients (with greater than 12 months follow up) were analyzed. Imaging was performed on a 1.5 Tesla Avanto, or 3.0 Tesla Verio MRI scanner (Siemens Medical Solutions). Cine images were performed using a steady state free precession pulse sequence. Delayed enhancement (DE) CMR was performed 10 minutes after administration of 0.15 mmol/kg Gadopentetate Dimeglumine (Bayer HealthCare) with typical in-plane resolution 18 x 2.0 mm, slice thickness 6-7 mm. LV and RV volumes and EF were analyzed by manual planimetry of endocardial contours during end-diastole and end-systole. DE-CMR images were analyzed to identify hyperenhanced myocardium (> 2 SD of remote signal intensity). The primary outcome was a combination of hospitalization for heart failure, LV assist device (LVAD) implantation, cardiac transplant, or death. Adjusted Kaplan-Meier curves were constructed for groups with and without scar by CMR with p<0.05 considered significant. Multivariate logistic regression analysis was performed. Results Patient’s demographics are shown in table. All baseline demographic data were similar between patients with and without scar by CMR. The adjusted event-free survival rate was significantly lower for patients with scar compared to patients without scar by CMR at 2-years (p=0.03) (graph). Mean scar burden was 3 ± 8% of LV. On multivariable analysis, the presence of scar was an independent predictor of events, HR 2.5(CI: 0.98-6.38, p=0.04), but LVEF was not. Conclusions In non-ischemic cardiomyopathy the presence of LV scar measured by DE-CMR is a stronger predictor of cardiovascular events than LVEF.

Delayed enhancement and myocardial velocity mapping CMR reveal differences in regional left ventricular function with varying levels of scar

Background Delayed enhancement (DE) CMR is the gold standard for detecting irreversibly damaged myocardial tissue (scar). Yet, direct impact of scar on regional systolic and diastolic left ventricular (LV) function is not well understood. Standard tools for LV velocities (Tissue Doppler Imaging) are limited by poor reproducibility and incomplete assessment of all regions and motion directions. Myocardial CMR velocity mapping (MVM) is reproducible, non-invasive, and allows direct measure of myocardial velocities of all LV motion components in all regions. Here, we analyze effects of LV scar burden on myocardial motion.

094: Contribution of cardiac MRI to early evaluation and impact on the long term follow-up in myocarditis mimicking an acute coronary syndrome. A 43-cases prospective study

Acute myocarditis (AM) diagnosis is a challenge to rule out an acute coronary syndrome (ACS). AM is thought to favour the evolution towards dilated cardiomyopathy (DCM) and the occurrence of severe arrhythmias. Three months after the acute episode, re-evaluation including cardiac MRI could help to identify patients at risk for unfavourable evolution. The use of MRI has rarely been investigated in AM prognosis stratification. we report a prospective series of 43 consecutive patients hospitalized for AM mimicking ACS: 36 men and 7 women, 32 years old on average, without sign of heart failure. All patients presented with troponine I elevation. Echocardiography showed moderate global left ventricular dysfunction in 6 cases and segmental wall motion abnormalities in 22. MRI performed early after admission never showed myocardial first-pass perfusion defect after gadolinium injection but subepicardial delayed-enhancement (DE) areas in 39 cases mainly located in lateral segments. Three months after the acute episode, no patient was symptomatic. Echocardiography, Holter monitoring and biological check-up were normal. MRI showed the persistence of DE in 23 cases without wall motion abnormality in the affected segments. The presence of these latter abnormalities led to effect an annually clinical examination with an ECG. One patient was lost at further follow-up. Among the other 22 patients, only one patient dysplayed heart failure revealing DCM with ventricular arrhythmias at 3 - year mean follow-up. at the time of admission, the absence of early perfusion defect at cardiac MRI after gadolinium injection and the subepicardial localization of the DE constitute reliable criteria in favour of AM diagnosis, allowing to rule out ACS. During the follow-up the persistence of a DE does not allow any prognosis stratification. In our series after a mean 3-year follow-up, it is not associated with any clinical and para-clinical disorder except in one case.

Integration of Merged Delayed‐Enhanced Magnetic Resonance Imaging and Multidetector Computed Tomography for the Guidance of Ventricular Tachycardia Ablation: A Pilot Study

Delayed enhancement (DE) MRI can assess the fibrotic substrate of scar-related VT. MDCT has the advantage of inframillimetric spatial resolution and better 3D reconstructions. We sought to evaluate the feasibility and usefulness of integrating merged MDCT/MRI data in 3D-mapping systems for structure-function assessment and multimodal guidance of VT mapping and ablation. Nine patients, including 3 ischemic cardiomyopathy (ICM), 3 nonischemic cardiomyopathy (NICM), 2 myocarditis, and 1 redo procedure for idiopathic VT, underwent MRI and MDCT before VT ablation. Merged MRI/MDCT data were integrated in 3D-mapping systems and registered to high-density endocardial and epicardial maps. Low-voltage areas (<1.5 mV) and local abnormal ventricular activities (LAVA) during sinus rhythm were correlated to DE at MRI, and wall-thinning (WT) at MDCT. Endocardium and epicardium were mapped with 391 ± 388 and 1098 ± 734 points per map, respectively. Registration of MDCT allowed visualization of coronary arteries during epicardial mapping/ablation. In the idiopathic patient, integration of MRI data identified previously ablated regions. In ICM patients, both DE at MRI and WT at MDCT matched areas of low voltage (overlap 94 ± 6% and 79 ± 5%, respectively). In NICM patients, wall-thinning areas matched areas of low voltage (overlap 63 ± 21%). In patients with myocarditis, subepicardial DE matched areas of epicardial low voltage (overlap 92 ± 12%). A total number of 266 LAVA sites were found in 7/9 patients. All LAVA sites were associated to structural substrate at imaging (90% inside, 100% within 18 mm). The integration of merged MDCT and DEMRI data is feasible and allows combining substrate assessment with high-spatial resolution to better define structure-function relationship in scar-related VT.

Abstract 19450: Manual Thrombus Aspiration is not Associated with Reduction in Infarct Size Assessed by Delayed Enhancement MDCT

Objective: We sought to assess whether manual thrombus aspiration could reduce infarct size in patients with acute ST-elevation myocardial infarction (MI) undergoing primary percutaneous coronary intervention (PCI). Background: The efficacy of manual thrombus aspiration during primary PCI for acute MI remains controversial. Methods: Between April 2009 and Mar 2011, 86 consecutive patients presenting with first acute STEMI (Killip≤II) within 12 hours after the symptom onset were randomized to manual thrombus aspiration (group I, N=44) or conventional PCI without thrombus aspiration (group II, N=42). The use of glycoprotein IIb/IIIa inhibitor (GPI) was left to the discretion of the operator. All patients received aspirin 300 mg and clopidogrel 600 mg before PCI and underwent delayed enhancement (DE) multi-detector computed tomography (MDCT) immediately after PCI without injection of an additional contrast media for assessment of infarct size, determined as the total volume of myocardium showing DE. DE MDCT was repeated at 2 months after PCI. The primary endpoint was infarct size reduction at 2 months. Results: Baseline clinical characteristics and angiographic findings were similar between the 2 groups. There were no differences between group I and II in symptom-to-door time, door-to-balloon time, PCI-to-MDCT time, Pre-PCI TIMI 0/1, post-PCI TIMI 3, or the use of GPI. Markers of myocardial reperfusion showed better outcome in group I but without statistical difference: ST-resolution rate &gt;70% (74% vs. 65%), myocardial blush grade 3 (88% vs. 68%), and corrected TIMI frame count &lt;28 (31% vs. 24%). Initial infarct size determined by DE MDCT and left ventricular ejection fraction (LVEF) by 2-dimensional echocardiography were similar between group I and II (17±18 mL vs. 22±23 mL and 58±11% vs. 55±10%, respectively). At 2 months, there was no difference in infarct size and left ventricular ejection fraction between the groups: 14±10 mL vs. 17±12 mL and 62±12% vs. 60±2%, respectively. No adverse cardiac events occurred in either group during the 2-month clinical follow-up. Conclusion: Manual thrombus aspiration was not associated with reduction in infarct size in patients with acute ST-elevation MI undergoing primary percutaneous coronary intervention.

Abstract 9292: Impact of Nicorandil on Infarct Myocardium in Comparison With Nitrate: Assessed by Cardiac Magnetic Resonance Imaging

Objectives The complementary intravenous administration of nicorandil, a hybrid compound of ATP-sensitive potassium channel opener and nitric donor, to percutaneous coronary intervention (PCI) reportedly has a protective effect on the infarct myocardium, leading to improve clinical outcome in patients with acute myocardial infarction (AMI). We compared the infarct and edema size in AMI patients intravenously treated by nicorandil with those by nitrate, using cardiac magnetic resonance (CMR) imaging. Methods The double-blinded trial was conducted in 52 AMI patients who successfully underwent emergency PCI. The patients were assigned to receive nicorandil or nitrate just before reperfusion at random. For the assessment of infarct and edema areas, short-axis T2w and delayed enhancement (DE) CMR images were acquired 6.1 ± 2.4 days after the onset of AMI. Results The edema size on T2w CMR was significantly larger than the infarct size on DE CMR (p &lt; 0.05). A significant correlation was observed between the peak creatine kinase (CK) levels and infarct size on DE CMR (r = 0.62, p &lt; 0.05) as well as the edema size on T2w CMR (r = 0.7, p &lt; 0.05) in patients treated by nicorandil. A similar correlation was seen between the peak CK levels and infarct size on DE CMR (r = 0.84, p &lt; 0.05) as well as the edema size on T2w CMR (r = 0.84, p &lt; 0.05) in patients treated by nitrate. The maximum serum CK level was significantly lower in patients treated by nicorandil than those by nitrate (2132 ± 1689 IU. vs 2785 ± 2121 IU. ; p &lt; 0.05). Both the edema size on T2w CMR and the infarct size on DE CMR were significantly smaller in patients treated by nicorandil than those by nitrate (edema size; 17.7 ± 9.9 % vs 21.9 ± 13.7 % ; infarct size; 10.3 ± 6.0 % vs 12.7 ± 6.9 % ; p &lt; 0.05, respectively). Conclusion Using CMR imaging, we demonstrate that the complementary intravenous administration of nicorandil to PCI provides more favorable effects in reducing myocardial damage compared with nitrate.

Automated segmentation and reconstruction of patient-specific cardiac anatomy and pathology from in vivo MRI*

This paper presents an automated method to segment left ventricle (LV) tissues from functional and delayed-enhancement (DE) cardiac magnetic resonance imaging (MRI) scans using a sequential multi-step approach. First, a region of interest (ROI) is computed to create a subvolume around the LV using morphological operations and image arithmetic. From the subvolume, the myocardial contours are automatically delineated using difference of Gaussians (DoG) filters and GSV snakes. These contours are used as a mask to identify pathological tissues, such as fibrosis or scar, within the DE-MRI. The presented automated technique is able to accurately delineate the myocardium and identify the pathological tissue in patient sets. The results were validated by two expert cardiologists, and in one set the automated results are quantitatively and qualitatively compared with expert manual delineation. Furthermore, the method is patient-specific, performed on an entire patient MRI series. Thus, in addition to providing a quick analysis of individual MRI scans, the fully automated segmentation method is used for effectively tagging regions in order to reconstruct computerized patient-specific 3D cardiac models. These models can then be used in electrophysiological studies and surgical strategy planning.

Modified cine inversion recovery pulse sequence for the quantification of myocardial T1 and gadolinium partition coefficient

To optimize and validate a modified cine inversion recovery sequence (MCine-IR) for myocardial T1 quantification and gadolinium partition coefficient (λ(Gd)) estimation at 1.5 T. The original version of the cine inversion recovery sequence was modified to allow fully transverse magnetization recovery between two successive inversion pulses. Sixty heart phases were acquired from a number of heart cycles determined on a patient heart rate basis. Phantom studies were carried out to find the optimal effective TR for myocardial and blood pool T1 quantifications in pre- and postcontrast studies. Four patients with myocardial infarct (MI) and 22 dilated cardiomyopathy (DCM) were investigated, as well as 11 healthy subjects used as controls. Effective TR was identified to be 5000 msec and 2000 msec, respectively, for pre- and postcontrast studies. A longer precontrast (948 ± 102 msec) and shorter postcontrast (348 ± 27 msec) T1 in ischemic patients relative to DCM (815 ± 98 msec, P = 0.03 and 409 ± 42 msec, P = 0.001) were noted in delayed enhancement (DE) areas. In MI patients λ(Gd) resulted higher than in DCM in DE areas (609 ± 167 vs. 422 ± 52, P = 0.01) but lower in segments not exhibiting DE (355 ± 100 vs. 398 ± 54, P = 0.02). It was feasible to measure T1 and λ(Gd) with MCine-IR and the results were in good agreement with the literature.

Speckle tracking echocardiography derived systolic longitudinal strain is better than rest single photon emission tomography perfusion imaging for nonviable myocardium identification

The aim was to compare the speckle tracking echocardiography (STE) derived systolic longitudinal strain (SL(Smax)) with rest single photon emission computed tomography (SPECT) perfusion imaging (Q(REST)), and to define the optimal cut-offs for SL(Smax) to discriminate transmural scar on contrast-enhanced magnetic resonance imaging (ceCMR). In 100 patients with chronic ischemic left ventricular (LV) dysfunction, myocardial viability was assessed using STE and rest SPECT to predict LV segmental relative extent of delayed enhancement (DE) >75% on ceCMR. Correlation was found between regional SL(Smax) (r=-0.59, P<0.0001) and DE on ceCMR. The SL(Smax) optimal cut-off -5.3% identified segments with DE>75% on ceCMR (sensitivity 83.1%, specificity 84.6%). Optimal cut-offs SL(Smax) for segments corresponding to individual perfusion territories (-3.6%, -5.3% and -4.7% for LAD, LCx resp. RCA perfusion territories) were identified. There was a significant difference (AUC 0.866 vs. 0.822 for SL(Smax) resp. Q(REST), p=0.036) in the accuracy of predicting non-viable segment due to the greater accuracy of SL(Smax) than Q(REST) in the RCA perfusion territory (AUC 0.893 vs. 0.75 for SLSmax resp. Q(REST), P=0.001). STE enabled identification of LV non-viable segments. Cut-off values derived for perfusion territories of individual coronary arteries improve the accuracy of predicting a transmural scar presence. In comparison with rest myocardial SPECT perfusion imaging, STE is more accurate in predicting non-viable myocardium.

Methodology for Jointly Assessing Myocardial Infarct Extent and Regional Contraction in 3-D CMRI

Automated extraction of quantitative parameters from cardiac magnetic resonance images is crucial for the management of patients with myocardial infarct. This paper proposes a postprocessing procedure to jointly analyze Cine and delayed-enhanced (DE) acquisitions, in order to provide an automatic quantification of myocardial contraction and enhancement parameters and a study of their relationship. For that purpose, the following processes are performed: 1) DE/Cine temporal synchronization and 3-D scan alignment, 2) 3-D DE/Cine rigid registration in a region about the heart, 3) myocardium segmentation on Cine-MRI and superimposition of the epicardial and endocardial contours on the DE images, 4) quantification of the myocardial infarct extent (MIE), 5) study of the regional contractile function using a new index, the amplitude to time ratio (ATR). The whole procedure was applied to ten patients with clinically proven myocardial infarction. The comparison between the MIE and the visually assessed regional function scores demonstrated that the MIE is highly related to the severity of the wall motion abnormality. In addition, it was shown that the newly developed regional myocardial contraction parameter (ATR) decreases significantly in delayed enhanced regions. This largely automated approach enables the combined study of regional MIE and left ventricular function.

Assessment of myocardial viability using multidetector computed tomography in patients with reperfused acute myocardial infarction

To assess the prognostic value of 64-section multidetector computed tomography (MDCT) to predict follow-up myocardial dysfunction and functional recovery after reperfusion therapy in patients with acute myocardial infarction (MI) as defined by echocardiography. After reperfusion therapy for acute MI, 71 patients underwent two-phase contrast-enhanced MDCT and follow-up echocardiography. MDCT findings were compared with echocardiographic findings using kappa statistics. The areas under the receiver operating characteristic curves (AUCs) and the odds ratios (ORs) of early perfusion defects (EPD), delayed enhancement (DE), and residual perfusion defects (RPD) for predicting follow-up myocardial dysfunction and functional recovery were calculated on a segmental basis. The presence of transmural EPD (EPD(TM)) or RPD showed good agreement (k = 0.611 and 0.658, respectively) with follow-up myocardial dysfunction, while subendocardial EPD (EPD(sub)) or subendocardial DE (DE(sub)) showed fair agreement with follow-up myocardial dysfunction (k = 0.235 and 0.234, respectively). The AUC of RPD (0.796) was superior (p < 0.001 and 0.031, respectively) to those of EPD(TM) (0.761) and DE(TM) (0.771). The presence of EPD(TM), DE(TM), and RPD were significant, independent positive predictors of follow-up myocardial dysfunction (OR = 6.4, 1.9, and 9.8, respectively). EPD(TM) was a significant, independent negative predictor of myocardial functional recovery (OR = 0.13). Abnormal myocardial attenuation on two-phase MDCT after reperfusion therapy may provide promising information regarding myocardial viability in patients with acute MI.

Whole-heart dynamic three-dimensional magnetic resonance perfusion imaging for the detection of coronary artery disease defined by fractional flow reserve: determination of volumetric myocardial ischaemic burden and coronary lesion location

Dynamic three-dimensional-cardiac magnetic resonance (3D-CMR) perfusion proved highly diagnostic for the detection of angiographically defined coronary artery disease (CAD) and has been used to assess the efficacy of coronary stenting procedures. The present study aimed to relate significant coronary lesions as assessed by fractional flow reserve (FFR) to the volume of myocardial hypoenhancement on 3D-CMR adenosine stress perfusion imaging and to define the inter-study reproducibility of stress inducible 3D-CMR hypoperfusion. A total of 120 patients with known or suspected CAD were examined in two CMR centres using 1.5 T systems. The protocol included cine imaging, 3D-CMR perfusion during adenosine infusion, and at rest followed by delayed enhancement (DE) imaging. Fractional flow reserve was recorded in epicardial coronary arteries and side branches with ≥2 mm luminal diameter and >40% severity stenosis (pathologic FFR < 0.75). Twenty-five patients underwent an identical repeat CMR examination for the determination of inter-study reproducibility of 3D-CMR perfusion deficits induced by adenosine. Three-dimensional CMR perfusion scans were visually classified as pathologic if one or more segments showed an inducible perfusion deficit in the absence of DE. Myocardial ischaemic burden (MIB) was measured by segmentation of the area of inducible hypoenhancement and normalized to left ventricular myocardial volume (MIB, %). Three-dimensional CMR perfusion resulted in a sensitivity, specificity, and diagnostic accuracy of 90, 82, and 87%, respectively. Substantial concordance was found for inter-study reproducibility [Lin's correlation coefficient: 0.98 (95% confidence interval: 0.96-0.99)]. Three-dimensional CMR stress perfusion provided high diagnostic accuracy for the detection of functionally significant CAD. Myocardial ischaemic burden measurements were highly reproducible and allowed the assessment of CAD severity.

Distal protection device aggravated microvascular obstruction evaluated by cardiac MR after primary percutaneous intervention for ST-elevation myocardial infarction

BackgroundProtection of distal embolization by balloon occlusion and thrombus aspiration has not improved microvascular circulation nor decreased myocardial injury during primary percutaneous intervention (PCI) for ST-elevation myocardial infarction (STEMI) in randomized trials. In a prospective randomized trial, we investigated the mechanism of the poor effect of distal protection and thrombus aspiration (DP–TA) in 126 patients with STEMI. MethodsPatients with first-diagnosed STEMI were randomly assigned to DP–TA pretreatment or conventional PCI (c-PCI). Primary endpoint was reduced left ventricular end-diastolic volume (LVEDV) measured by MRI at post-PCI and 6months after PCI. Secondary end points were infarct ratio (infarct size to entire LV size) by delayed enhancement (DE), area at risk (AAR) ratio (AAR to entire LV size) by T2 high signal, microvascular occlusion index (MVO) ratio (MVO to entire LV size) by DE, and myocardial salvage index (MSI: (AAR−infarct size)∗100/AAR) using cardiac magnetic resonance imaging (MRI) within 3days after PCI. ResultsBaseline characteristics of the patients including cardiovascular risk factors and lesion characteristics were similar between the two groups. DT–PA failed to improve LV remodeling at 6months (LVEDV 140±39 vs 133±37 in c-PCI group, p=0.418). Infarct ratio, AAR ratio and MSI were not statistically different between DP–TA group and c-PCI group. However, MVO ratio was significantly larger in DP–TA group than in c-PCI group (2.4±2.7 vs 1.1±1.9, p=0.045). ConclusionDP–TA was potentially hazardous in primary PCI for STEMI by increasing MVO. DP–TA should not be used in STEMI.