Influence of left ventricular hypertrophy on infarct size and left ventricular ejection fraction in ST-elevation myocardial infarction

Background

Left ventricular hypertrophy (LVH) predisposes to larger infarct size, which may be underestimated by the left ventricular ejection fraction (LVEF) due to supranormal systolic performance often present in patients with LVH. The aim of the study was to compare infarct size and LVEF in patients with ST-segment elevation myocardial infarction (STEMI) and increased left ventricular mass on cardiac magnetic resonance (CMR).

Methods

The study included unselected group of 52 patients (61 ± 11 years, 69% male) with first STEMI who had CMR after median 5 days from the onset of the event. Left ventricular hypertrophy (LVH) was defined as left ventricular mass index exceeding 95th percentile of references values for age and gender. Infarct size was assessed with means of late gadolinium enhancement (LGE).

Results

LVH was found in 16 patients (31%). In comparison to the rest of the group, patients with LVH had higher absolute and relative infarct mass (p = 0.002 and p = 0.02, respectively). LVH was related to higher prevalence of microvascular obstruction and myocardial haemorrhage and higher number of LV segments with transmural necrosis (p = 0.02, p = 0.01 and p = 0.01, respectively). Despite marked difference in the infarct size between both studied subgroups there was no difference in LVEF and mean number of dysfunctional LV segments.

Conclusions

Patients with LVH undergoing STEMI have larger infarct size underestimated by the LV systolic performance in comparison to patients without LVH.     

Left ventricular thrombus formation after acute myocardial infarction as assessed by cardiovascular magnetic resonance imaging

Introduction

Left ventricular (LV) thrombus formation is a feared complication of myocardial infarction (MI). We assessed the prevalence of LV thrombus in ST-segment elevated MI patients treated with percutaneous coronary intervention (PCI) and compared the diagnostic accuracy of transthoracic echocardiography (TTE) to cardiovascular magnetic resonance imaging (CMR). Also, we evaluated the course of LV thrombi in the modern era of primary PCI.

Methods

200 patients with primary PCI underwent TTE and CMR, at baseline and at 4 months follow-up. Studies were analyzed by two blinded examiners. Patients were seen at 1, 4, 12, and 24 months for assessment of clinical status and adverse events.

Results

On CMR at baseline, a thrombus was found in 17 of 194 (8.8%) patients. LV thrombus resolution occurred in 15 patients. Two patients had persistence of LV thrombus on follow-up CMR. On CMR at four months, a thrombus was found in an additional 12 patients. In multivariate analysis, thrombus formation on baseline CMR was independently associated with, baseline infarct size (g) (B = 0.02, SE = 0.02, p < 0.001). Routine TTE had a sensitivity of 21–24% and a specificity of 95–98% compared to CMR for the detection of LV thrombi. Intra- and interobserver variation for detection of LV thrombus were lower for CMR (κ = 0.91 and κ = 0.96) compared to TTE (κ = 0.74 and κ = 0.53).

Conclusion

LV thrombus still occurs in a substantial amount of patients after PCI-treated MI, especially in larger infarct sizes. Routine TTE had a low sensitivity for the detection of LV thrombi and the interobserver variation of TTE was large.     

Cardiac MR assessment of microvascular obstruction

Microvascular obstruction (MVO) is usually seen in a proportion of patients with acute myocardial infarction following reperfusion therapy of an occluded coronary artery. It is characterized by damage and dysfunction of the myocardial microvasculature with a no-reflow phenomenon within the infarct zone. While MVO may be demonstrated via a number of different imaging modalities, cardiac MR (CMR) enables accurate identification of MVO and also permits assessment of infarct extent and overall left ventricular function during the same imaging examination. We present a pictorial review of the characteristic appearances of MVO on CMR and highlight the importance of this imaging diagnosis for patient outcome following acute myocardial infarction.Microvascular obstruction (MVO) usually arises following reperfusion therapy in patients after a prolonged period of severe myocardial ischaemia.^1,2 It is most commonly, but not exclusively, seen in patients with a delayed presentation to definitive reperfusion treatment following acute coronary occlusion.^3,4 MVO was first described in the 1970s and is characterized by damage and dysfunction of the myocardial microvasculature resulting in a “no-reflow” phenomenon, where, essentially, blood flow cannot penetrate beyond the myocardial capillary bed.³ While several different imaging modalities may be utilized in the diagnosis of MVO, cardiac MR (CMR) has a number of distinct advantages as it enables precise delineation of both infarct site and MVO along with accurate quantification of both global and segmental left ventricular function during a single imaging examination. Accurate diagnosis of MVO is of great importance, as its presence has been shown to be an independent predictor of poor prognostic outcome following myocardial infarction, including adverse left ventricular remodelling, subsequent major adverse cardiovascular events and death.^1,4–6     

The relation between hypointense core,microvascular obstruction and intramyocardial haemorrhage in acute reperfused myocardial infarction assessed by cardiac magnetic resonance imaging

Background

Intramyocardial haemorrhage (IMH) and microvascular obstruction (MVO) represent reperfusion injury after reperfused ST-elevation myocardial infarction (STEMI) with prognostic impact and “hypointense core” (HIC) appearance in T₂-weighted images. We aimed to distinguish between IMH and MVO by using T₂ ^*-weighted cardiovascular magnetic resonance imaging (CMR) and analysed influencing factors for IMH development.

Methods and results

A total of 151 patients with acute STEMI underwent CMR after primary angioplasty. T₂-STIR sequences were used to identify HIC, late gadolinium enhancement to visualise MVO and T₂ ^*-weighted sequences to detect IMH. IMH⁺/IMH^? patients were compared considering infarct size, myocardial salvage, thrombolysis in myocardial infarction (TIMI) flow, reperfusion time, ventricular volumes, function and pre-interventional medication. Seventy-six patients (50 %) were IMH⁺, 82 (54 %) demonstrated HIC and 100 (66 %) MVO. IMH was detectable without HIC in 16 %, without MVO in 5 % and HIC without MVO in 6 %. Multivariable analyses revealed that IMH was associated with significant lower left ventricular ejection fraction and myocardial salvage index, larger left ventricular volume and infarct size. Patients with TIMI flow grade ≤1 before angioplasty demonstrated IMH significantly more often.

Conclusions

IMH is associated with impaired left ventricular function and higher infarct size. T₂ and HIC imaging showed moderate agreement for IMH detection. T₂ ^* imaging might be the preferred CMR imaging method for comprehensive IMH assessment.

Key Points

? Intramyocardial haemorrhage is a common finding in patients with acute reperfused myocardial-infarction. ? T ₂ ^* imaging should be the preferred CMR method for assessment of intramyocardial haemorrhage. ? Intramyocardial haemorrhage can be considered as an important influencing factor on patient’s outcome.     

Magnetic resonance-derived circumferential strain provides a superior and incremental assessment of improvement in contractile function in patients early after ST-segment elevation myocardial infarction

Background

We evaluate whether circumferential strain derived from grid-tagged CMR is a better method for assessing improvement in segmental contractile function after STEMI compared to late gadolinium enhancement (LGE).

Methods

STEMI patients post primary PCI underwent baseline CMR (day 3) and follow-up (day 90). Cine, grid-tagged and LGE images were acquired. Baseline LGE infarct hyperenhancement was categorised as ≤25 %, 26-50 %, 51-75 % and >75 % hyperenhancement. The segmental baseline circumferential strain (CS) and circumferential strain rate (CSR) were calculated from grid-tagged images. Segments demonstrating an improvement in wall motion of ≥1 grade compared to baseline were regarded as having improved segmental contractile-function.

Results

Forty-five patients (aged 58?±?12 years) and 179 infarct segments were analysed. A baseline CS cutoff of -5 % had sensitivity of 89 % and specificity of 70 % for detection of improvement in segmental-contractile-function. On receiver-operating characteristic analysis for predicting improvement in contractile function, AUC for baseline CS (0.82) compared favourably to LGE hyperenhancement (0.68), MVO (0.67) and baseline-CSR (0.74). On comparison of AUCs, baseline CS was superior to LGE hyperenhancement and MVO in predicting improvement in contractile function (P?<?0.001). On multivariate-analysis, baseline CS was the independent predictor of improvement in segmental contractile function (P?<?0.001).

Conclusion

Grid-tagged CMR-derived baseline CS is a superior predictor of improvement in segmental contractile function, providing incremental value when added to LGE hyperenhancement and MVO following STEMI.

Key points

? Baseline CS predicts contractile function recovery better than LGE and MVO following STEMI ? Baseline CS predicts contractile function recovery better than baseline CSR following STEMI ? Baseline CS provides incremental value to LGE and MVO following STEMI     

Scintigraphic evaluation of routine filterwire distal protection in percutaneous coronary intervention for acute ST-segment elevation myocardial infarction: a randomized controlled trial

Aim

Distal embolization during primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) may result in reduced myocardial perfusion, infarct extension and impaired prognosis. In a prospective randomized trial, we assessed the effect of routine filterwire distal protection on scintigraphic estimated infarct size.

Methods and results

The effect of routine filterwire distal protection was evaluated in 344 patients with STEMI <12 hours undergoing primary PCI. Patients were randomized to distal protection with a filterwire or standard PCI. The primary endpoint was myocardial infarct size measured by Sestamibi SPECT after 30 days (%). Secondary endpoints included myocardial salvage, ST-segment resolution (STR), myocardial biomarker release and major adverse cardiac and cerebral events. Baseline characteristics including area at risk (estimated by Sestamibi SPECT) were similar. Final infarct size was not statistically different in the distal protection and the control groups (median [IQR], 6% [1-19] and 5% [1-14], P = .23). Also, secondary endpoints were similar in the two treatment groups.

Conclusion

Distal protection with a filterwire performed as routine therapy in primary PCI for STEMI did not reduce myocardial infarct size. The study does not support routine use of distal protection in primary PCI.     

Diagnostic performance of combined cardiac MRI for detection of coronary artery disease

Objective

To evaluate the diagnostic performance of stress perfusion cardiac MR (CMR) for detecting significant CAD (≥70% narrowing) in comparison with invasive coronary angiography (ICA) as a reference standard.

Methods

Examinations of 54 patients who underwent both stress perfusion CMR and ICA for investigation of CAD between 2007 and 2009 were evaluated. The CMR protocol included dipyridamole stress and rest perfusion, stress and rest cine MRI for assessment of ventricular function and delayed gadolinium enhancement for assessment of myocardial viability and detection of infarction. CMR interpretation was performed by 2 observers blinded to the results of ICA and the clinical history.

Results

From a total of 54 patients, 37 (68.5%) showed significant CAD in 71 coronary territories. A perfusion defect was detected in 35 patients and in 69 coronary territories. Individual stress perfusion CMR evaluation showed the highest accuracy (83%) of the CMR techniques. The combined analysis using all sequences increased the overall accuracy of CMR to 87%.

Conclusion

Combination of perfusion and cine-MR during stress/rest, associated to delayed enhancement in the same protocol improves CMRI diagnostic accuracy and sensitivity for patients with significant coronary stenosis, and may therefore be helpful for risk stratification and defining treatment strategies.     

Cardiac index after acute ST-segment elevation myocardial infarction measured with phase-contrast cardiac magnetic resonance imaging

Objectives

Phase-contrast CMR (PC-CMR) might provide a fast and robust non-invasive determination of left ventricular function in patients after ST-segment elevation myocardial infarction (STEMI).

Methods

Cine sequences in the left-ventricular (LV) short-axis and free-breathing, retrospectively gated PC-CMR were performed in 90 patients with first acute STEMI and 15 healthy volunteers. Inter- and intra-observer agreement was determined. The correlations of clinical variables (age, gender, ejection fraction, NT pro-brain natriuretic peptide [NT-proBNP] with cardiac index (CI) were calculated.

Results

For CI, there was a strong agreement of cine CMR with PC-CMR in healthy volunteers (r: 0.82, mean difference: -0.14 l/min/m², error?±?23 %). Agreement was lower in STEMI patients (r: 0.61, mean difference: -0.17 l/min/m², error?±?32 %). In STEMI patients, CI measured with PC-CMR showed lower intra-observer (1 % vs. 9 %) and similar inter-observer variability (9 % vs. 12 %) compared to cine CMR. CI was significantly correlated with age, ejection fraction and NT-proBNP values in STEMI patients.

Discussion

The agreement of PC-CMR and cine CMR for the determination of CI is lower in STEMI patients than in healthy volunteers. After acute STEMI, CI measured with PC-CMR decreases with age, LV ejection fraction and higher NT-proBNP.

Key Points

? Cine CMR and PC-CMR correlate well in healthy volunteers.? Agreement is lower in STEMI patients.? Cardiac Output should be measured with one method longitudinally.? Cardiac output decreases with age after myocardial infarction.

     

Is myocardial stress perfusion MR-imaging suitable to predict the long term clinical outcome after revascularization?

Introduction

Aim of our study was to evaluate, whether myocardial ischemia or myocardial infarction (MI) depicted by myocardial stress perfusion MR imaging (SP CMR) can predict the clinical outcome in patients with coronary artery disease (CAD).

Materials and method

220 patients were included. Myocardial perfusion was assessed at stress and at rest, using a 2D saturation recovery gradient echo sequence (SR GRE) and myocardial viability by late gadolinium enhancement magnetic resonance images (LGE CMR). MR-images were assessed in regard of presence and extent of MI and ischemia. Patients were monitored for major adverse cardiac events (MACE) (monitoring period: 5–7 years). MACE were correlated with the initial results of SP CMR.

Results

Ischemia was found in 143 patients, MI in 107 patients. Number of MACE was in patients with normal SP CMR 0 (51 patients), with ischemia 21 (62 patients), with MI 14 (26 patients), with ischemia and MI 52 (81 patients). In all patients with severe MACE (MI, death) and in 63 of those with recurring symptoms LGE CMR revealed MI at baseline.

Conclusion

Negative SP CMR indicates low risk for MACE. In patients with stress induced ischemia, MACE might occur even after myocardial revascularization. The presence of MI proved by LGE CMR is associated with a significantly increased risk for MACE.     

Does magnetic resonance imaging have a role in diagnosing benign intracardiac lesions?

Objective

In this study, transthoracic echocardiography and cardiac magnetic resonance were compared in terms of the detection, localization, characterization and extra cardiac association of cardiac lesions to specify the value of adding CMR to TTE in diagnosing benign intracardiac lesions.

Materials and methods

Twenty nine patients ranging in age between 7 months and 80 years were enrolled in the study. Twenty five patients with suspected intracardiac lesions by TTE, in addition four patients with accidentally discovered thrombi on CMR were added to the study.

Results

CMR detected 17 non neoplastic lesions and 11 neoplastic lesions. CMR changed the diagnosis made by TTE in five cases, showed additional findings to TTE in three cases and was superior to TTE in detecting four cases of cardiac thrombi.

Conclusion

CMR is superior to TTE in characterization of intracardiac lesions, detecting its site, size, vascularity, hemodynamics and multiplicity of the lesion with high tissue contrast. Thus it should be performed in all cases suspicious of cardiac masses as it could aid in patient management and guide for surgery. Moreover it can prevent unneeded cardiac surgery in cases of benign non-neoplastic lesions or in benign tumors with no hemodynamic significance.     

Accuracy of a new method for semi-quantitative assessment of right ventricular ejection fraction by cardiovascular magnetic resonance: Right ventricular fractional diameter changes

Objective

Longitudinal shortening is traditionally considered the predominant part of global right ventricular (RV) systolic function. Less attention has been paid to transverse contraction. The aim of this study was to evaluate RV transverse motion by cardiovascular magnetic resonance (CMR) in a large cohort of patients and to assess its relationship with RV ejection fraction (RVEF).

Study design

We retrospectively analyzed the CMR scans of 300 patients referred to our center in 2010. RVEF was determined from short axis sequences using the volumetric method. Transverse parameters called RV fractional diameter changes were calculated after measuring RV diastolic and systolic diameters at basal and mid-level in short axis view (respectively FBDC and FMDC). We also measured the tricuspid annular plane systolic excursion (TAPSE) as a longitudinal reference.

Results

Our population was divided into 2 groups according to RVEF. 250 patients had a preserved RVEF (>40%) and 50 had a RV dysfunction (RVEF ≤40%). Transverse and longitudinal motions were significantly reduced in the group with RV dysfunction (p < .0001). After ROC analysis, areas under the curve for FBDC, FMDC and TAPSE, were respectively 0.79, 0.82 and 0.72, with the highest specificity and sensitivity respectively of 88% and 68% for FMDC (threshold at 20%) for predicting RV dysfunction. FMDC had an excellent negative predictive value of 93%.

Conclusion

RV fractional diameter changes, especially at the mid-level, appear to be accurate for semi-quantitative assessment of RV function by CMR. A cut-off of 20% for FMDC differentiates patients with a low (EF ≤ 40%) or a preserved RVEF.     

Follow-up of hepatic and peritoneal metastases of gastrointestinal tumors (GIST) under Imatinib therapy requires different criteria of radiological evaluation (size is not everything!!!)

Purpose

To define computed tomography (CT) criteria for evaluating the response of patients with gastrointestinal stromal tumors (GIST) who are receiving Imatinib (tyrosine-kinase inhibitor therapy).

Materials and methods

This prospective CT study evaluated 107 consecutive patients with advanced metastatic GIST treated with Imatinib.

Results

Seventy patients had total or partial cystic-like transformation of hepatic and/or peritoneal metastases. These pseudocysts remained unchanged in size or stable in size on successive CT examinations (stable disease according to RECIST criteria). Forty-six patients developed metastases, 17 patients showed increasing parietal thickness and 29 patients with peripheral enhancing nodules. These CT changes represented local recurrence consistent with GIST resistance to Imatinib treatment. WHO or RECIST criteria did not provide a reliable evaluation of disease evolution or recurrence. Development of new enhancement of lesions (parietal thickness or nodule) was the only reliable criterion.

Conclusion

The development of peripheral thickening or enhancing nodules within cystic-like metastatic lesions, even without any change in size, represented progressive GIST under Imatinib, growing in a short time and should alert the clinician for the possible need for a change in therapy.     

Evaluation of lacrimal drainage system obstruction using combined multidetector CT and instillation dacryocystography

Aim of the work

To assess the use of combined multidetector computed tomography and instillation dacryocystography (CTDCG) in detection of the level lacrimal drainage system (LDS) obstruction.

Methods

Twenty-one patients with one-sided epiphora were our candidates for CTDCG. Axial source and post processing images were assessed for clear viewing and the ability to detect the level of LDS obstruction. To our knowledge, no previous studies used this combination in the assessment of the LDS obstruction.

Results

All patients tolerated the examination well. Various levels of LDS obstruction were detected, common canaliculus in 4 (19%) patients, lacrimal sac in 3 (14.2%), junction between lacrimal sac and NLD in 9 (42.8%) and NLD obstruction in 5 (23.8%) patients. The most common CTDCG findings were dilated opacified lacrimal sac with no opacification of the nasolacrimal duct (NLD) in 9/21 (42.8%) patients. Curved planner reformation (CPR) were excellent to detect the nasolacrimal duct (NLD) obstruction.

Conclusion

CTDCG is a non-invasive patient friendly procedure that adds benefit in documentation and preoperative planning.     

Breast cancer size estimation with MRI in BRCA mutation carriers and other high risk patients

Objective

To assess the value of breast MRI in size assessment of breast cancers in high risk patients, including those with a BRCA 1 or 2 mutation. Guidelines recommend invariably breast MRI screening for these patients and therapy is thus based on these findings. However, the accuracy of breast MRI for staging purposes is only tested in sporadic cancers.

Methods

We assessed concordance of radiologic staging using MRI with histopathology in 49 tumors in 46 high risk patients (23 BRCA1, 12 BRCA2 and 11 Non-BRCA patients). The size of the total tumor area (TTA) was compared to pathology. In invasive carcinomas (n = 45) the size of the largest focus (LF) was also addressed.

Results

Correlation of MRI measurements with pathology was 0.862 for TTA and 0.793 for LF. TTA was underestimated in 8(16%), overestimated in 5(10%), and correctly measured in 36(73%) cases. LF was underestimated in 4(9%), overestimated in 5(11%), and correctly measured in 36(80%) cases. Impact of BRCA 1 or 2 mutations on the quality of size estimation was not observed.

Conclusions

Tumor size estimation using breast MRI in high risk patients is comparable to its performance in sporadic cancers. Therefore, breast MRI can safely be used for treatment planning.     

Evaluation of left ventricle diastolic dysfunction in ischemic heart disease by CMR: Correlation with echocardiography and myocardial scarring

Objective

To detect the value of cardiac MR imaging in assessment of left ventricle diastolic function in patients with ischemic heart disease compared to echocardiography and to correlate the degree of dysfunction to the extent of myocardial scarring.

Patients and methods

We examined 40 patients with known coronary artery disease. Mean patient’s age was 48 ± 10. All patients were subjected to 2D echocardiography and CMR including transmitral flow and left atrial planimetry. The degree of diastolic dysfunction was detected and correlated with the echocardiographic results and the extent of myocardial scarring.

Results

On CMR, 35% of the cases had grade I diastolic dysfunction, 35% showed grade II, 15% had grade III while 15% showed normal diastolic function. CMR showed 94.12% sensitivity, 100% specificity and 95% accuracy. Excellent agreement with echocardiography was detected (Kappa coefficient 0.931). There was a significant correlation between the degree of diastolic dysfunction and the extent of myocardial scarring with Spearman’s correlation coefficient of 0.492 and p = 0.028.

Conclusion

CMR has comparative results to echocardiography in assessment of diastolic dysfunction. We found a significant correlation between the degree of diastolic dysfunction and the extent of myocardial scarring.     

Ossification variants of the femoral condyles are not associated with osteochondritis dissecans

Purpose

To determine if ossification variants of the femoral condyles involving the subchondral bone plate are associated with osteochondritis dissecans (OCD).

Materials and methods

The prevalence of ossification variants of the unaffected femoral condyle in 116 patients (aged 9–14 years) with unicondylar OCD on MRI (magnetic resonance imaging) of the knee was compared to a control group of 579 patients (aged 9–14 years) without OCD. The evolution of the ossification variants in both groups was studied by reviewing follow-up MR imaging side by side with the baseline study.

Results

The prevalence of ossification variants in the unaffected condyle in patients with OCD (12.9%) and in the control group of patients without OCD (12.6%) was similar (p = 0.88).Evolution of ossification variants to OCD was not seen on follow-up MRI examinations. All variants had decreased in size or were no longer visible.

Conclusion

Ossification variants of the femoral condyle that involve the subchondral bone plate are not associated with OCD.

Clinical relevance statement

Ossification variants are not associated with OCD, indicating that routine MRI follow-up in affected children is not mandatory.     

Quantification of myocardial delayed enhancement and wall thickness in hypertrophic cardiomyopathy: Multidetector computed tomography versus magnetic resonance imaging

Objectives

To evaluate the accuracy of multidetector computed tomography (MDCT) in assessing myocardial delayed enhancement and left ventricle wall thickness in hypertrophic cardiomyopathy (HCM) compared with cardiac magnetic resonance (CMR) as the reference standard.

Materials and methods

Eighty consecutive patients (59 male; 53.2 ± 13.0 years) were examined with MDCT, followed by CMR 1 day later. Cardiac CT angiography and a delayed CT were performed. CMR was performed according to a standardized protocol. Left ventricle wall thickness and positions of myocardial delayed enhancement were identified in both CMR and CT images according to the American Heart Association left ventricle 17-segment model. Myocardial delayed enhancement was characterized as “dense” (areas with clear defined borders) or “diffuse” and then quantified using both techniques.

Results

Left ventricle wall thickness determined by MDCT was significantly correlated with CMR (R = 0.88, P < 0.01). Compared with CMR, MDCT accurately diagnosed 74 of 78 (94.9%) patients and 1243 of 1326 (93.7%) segments. For dense myocardial delayed enhancement, MDCT significantly correlated with CMR (R = 0.88, P < 0.01) and slightly underestimated myocardial delayed enhancement (mean, −3.85%; lower and upper limits of agreement, −13.40% and 5.70%, respectively).

Conclusions

MDCT provides reliable quantification of myocardial delayed enhancement and evaluation of left ventricle wall thickness and has a good correlation with CMR in patients with HCM when a comprehensive cardiac CT protocol is used and can be applied for intervention planning.     

Acute myocardial infarction: early CT aspects of myocardial microcirculation obstruction after percutaneous coronary intervention

Objective

To evaluate the capabilities of delayed enhanced multidetector CT (DE-MDCT), performed immediately after percutaneous coronary intervention (PCI), in predicting myocardial microvascular obstruction (MVO) formation assessed by delayed enhanced MRI (DE-MRI).

Methods

Thirty-two patients presenting with a primary acute myocardial infarction, successfully recanalised by PCI, underwent a DE-MDCT immediately after PCI and a DE-MRI within 1 week. The left ventricle was split into 64 subsegments, rated as “healthy”, “infarcted” or “MVO” on DE-MRI. Their mean density was measured on DE-MDCT and calculated relative to the patient's mean healthy myocardium density. Hypoenhanced DE-MDCT subsegments, termed “CT early MVO”, were also recorded. Sensitivity and specificity of DE-MDCT for MRI-assessed “MVO” subsegments detection was calculated for mean CT relative density (threshold determined from a ROC analysis), “CT early MVO” and both.

Results

Mean CT relative density was higher in MRI-assessed “MVO” than in “infarcted” and “healthy” subsegments (1.82?±?0.46, 1.43?±?0.36 and 1.0?±?0.13 respectively; P?<?0.001) leading to a sensitivity and specificity of 94.3 % and 89.2 % for a cutoff of 1.36. Sensitivity and specificity were respectively 16.9 % and 99.8 % for “CT early MVO” and 95.3 % and 89.3 % when considering the two patterns.

Conclusion

DE-MDCT, performed immediately after PCI, allows for an accurate prediction of MVO formation.

Key Points

? Myocardial microvascular obstruction (MVO) is an important prognostic sequel following myocardial infarction. ? MVO can be accurately predicted by multidector CT (MDCT). ? Both hypo- and hyperenhanced myocardial areas can be analysed by MDCT. ? MDCT may become a useful prognostic tool for acute MI outcome.     

CMR assessment after a transapical-transcatheter aortic valve implantation

Aims

To describe the time course of myocardial scarring after transapical-transcatheter aortic valve implantation (TA-TAVI) with the Edwards SAPIEN XT™ and the Edwards SAPIEN™ prosthesis in a 3-month follow-up study using cardiac magnetic resonance imaging (CMR).

Methods

In 20 TA-TAVI patients, CMR was performed at discharge and 3 months (3M). Cine-MRI was used for left ventricular (LV) functional assessment, and late gadolinium enhancement (LGE) imaging was employed for detecting the presence of myocardial scarring. Special attention was given to any artifacts caused by the prosthesis, which were consequently defined using a three-grade artifact scale.

Results

We systematically reported the presence of small LGE hyperintensity relating to the apical segment, with no variation found between discharge and 3 M (2.8 ± 1.6 g vs. 2.35 ± 1.1 g). LV ejection fraction, end-diastolic, and end-systolic volumes did not significantly vary. A small area of apical akinesia was observed, with no improvement at follow-up. Whereas the Edwards SAPIEN XT™ prosthesis and the Edwards SAPIEN™ prosthesis are both constituted by metallic stenting structure, the Edwards SAPIEN™ was responsible for a larger signal void, thus potentially limiting the diagnostic performance of CMR.

Conclusions

CMR may be performed safely in the context of TA-TAVI. The presence of a very small apical infarction correlating with focal akinesia was observed. As expected, the Edwards SAPIEN XT™ prosthesis was shown to be particularly suitable for CMR assessment.     

Patterns of myocardial perfusion in the acute and chronic stage after myocardial infarction: a cardiac magnetic resonance study

Objectives

The aim of the present study was to monitor the microvascular perfusion damage in the acute and chronic stage after myocardial infarction (MI) using first-pass dynamic magnetic resonance imaging (MRI). Furthermore we compared improvement of myocardial microcirculation and function in infarcted and non-infarcted left midventricular segments over a 4 months period.

Materials and methods

Cardiac magnetic resonance imaging (CMR) was performed in 46 consecutive patients within 8 days after successful reperfused first acute ST-elevation MI and 4 months thereafter. First-pass images were obtained by using Turbo-FLASH sequence during a bolus injection of Gd-based contrast agent. Signal-intensity-to-time (SIT) curves of 276 left ventricular myocardial segments were generated. Furthermore, infarct volumes as well as parameters of regional left ventricular function of corresponding segments were calculated.

Results

SIT curves highly significantly correlate with MI size (r = −0.57, r = −0.43 respectively; all p < 0.0001) as well as with segmental wall thickening (SWT) of corresponding segments at baseline and follow-up scans (r = 0.20, r = 0.15 respectively; all p < 0.02). SWT differ highly significantly between segments with and those without LE at baseline (p < 0.003) and follow-up examinations (p < 0.008), presenting either clear improvements at follow-up (all p < 0.0001). In contrast, infarcted segments showing microvascular obstruction evidenced neither significant recovery of SIT nor of SWT (p = NS).

Conclusion

Our data indicate a close relationship between MI size and myocardial perfusion as well as function. Beyond epicardial artery patency, the assessment of quantitative parameters of myocardial perfusion and contractile function with the help of CMR appears to be a useful tool for estimating myocardial recovery after acute MI.