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Abstract Background Adenosine stress cardiovascular magnetic resonance (CMR) has been proven an effective tool in detection of reversible ischemia. Limited evidence is available regarding its accuracy in the setting of acute coronary syndromes, particularly in evaluating the significance of non-culprit vessel ischaemia. Adenosine stress CMR and recent advances in semi-quantitative image analysis may prove effective in this area. We sought to determine the diagnostic accuracy of semi-quantitative versus visual assessment of adenosine stress CMR in detecting ischemia in non-culprit territory vessels early after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). Methods Patients were prospectively enrolled in a CMR imaging protocol with rest and adenosine stress perfusion, viability and cardiac functional assessment 3 days after successful primary-PCI for STEMI. Three short axis slices each divided into 6 segments on first pass adenosine perfusion were visually and semi-quantitatively analysed. Diagnostic accuracy of both methods was compared with non-culprit territory vessels utilising quantitative coronary angiography (QCA) with significant stenosis defined as ≥70%. Results Fifty patients (age 59 ± 12 years) admitted with STEMI were evaluated. All subjects tolerated the adenosine stress CMR imaging protocol with no significant complications. The cohort consisted of 41% anterior and 59% non anterior infarctions. There were a total of 100 non-culprit territory vessels, identified on QCA. The diagnostic accuracy of semi-quantitative analysis was 96% with sensitivity of 99%, specificity of 67%, positive predictive value (PPV) of 97% and negative predictive value (NPV) of 86%. Visual analysis had a diagnostic accuracy of 93% with sensitivity of 96%, specificity of 50%, PPV of 97% and NPV of 43%. Conclusion Adenosine stress CMR allows accurate detection of non-culprit territory stenosis in patients successfully treated with primary-PCI post STEMI. Semi-quantitative analysis may be required for improved accuracy. Larger studies are however required to demonstrate that early detection of non-culprit vessel ischemia in the post STEMI setting provides a meaningful test to guide clinical decision making and ultimately improved patient outcomes.

Abstract Background Many adult patients with secundum-type atrial septal defects (ASDs) are able to have these defects fixed percutaneously. Traditionally, this has involved an assessment of ASD size, geometry and atrial septal margins by transoesophageal echocardiography (TOE) prior to percutaneous closure. This is a semi-invasive technique, and all of the information obtained could potentially be obtained by non-invasive cardiovascular magnetic resonance (CMR). We compared the assessment of ASDs in consecutive patients being considered for percutaneous ASD closure using CMR and TOE. Methods Consecutive patients with ASDs diagnosed on transthoracic echocardiography (TTE) were invited to undergo both CMR and TOE. Assessment of atrial septal margins, maximal and minimal defect dimensions was performed with both techniques. Analyses between CMR and TOE were made using simple linear regression and Bland Altman Analyses. Results Total CMR scan time was 20 minutes, and comparable to the TOE examination time. A total of 20 patients (M:F = 5:15, mean age 42.8 years ± 15.7) were included in the analyses. There was an excellent agreement between CMR and TOE for estimation of maximum defect size (R = 0.87). The anterior inferior, anterior superior and posterior inferior margins could be assessed in all patients with CMR. The posterior superior margin could not be assessed in only one patient. Furthermore, in 1 patient in whom TOE was unable to be performed, CMR was used to successfully direct percutaneous ASD closure. Conclusions CMR agrees with TOE assessment of ASDs in the work-up for percutaneous closure. Potentially CMR could be used instead of TOE for this purpose.

Abstract Background Pericardial adipose tissue (PAT) has been shown to be an independent predictor of coronary artery disease. To date its assessment has been restricted to the use of surrogate echocardiographic indices such as measurement of epicardial fat thickness over the right ventricular free wall, which have limitations. Cardiovascular magnetic resonance (CMR) offers the potential to non-invasively assess total PAT, however like other imaging modalities, CMR has not yet been validated for this purpose. Thus, we sought to describe a novel technique for assessing total PAT with validation in an ovine model. Methods 11 merino sheep were studied. A standard clinical series of ventricular short axis CMR images (1.5T Siemens Sonata) were obtained during mechanical ventilation breath-holds. Beginning at the mitral annulus, consecutive end-diastolic ventricular images were used to determine the area and volume of epicardial, paracardial and pericardial adipose tissue. In addition adipose thickness was measured at the right ventricular free wall. Following euthanasia, the paracardial adipose tissue was removed from the ventricle and weighed to allow comparison with corresponding CMR measurements. Results There was a strong correlation between CMR-derived paracardial adipose tissue volume and ex vivo paracardial mass (R2 = 0.89, p < 0.001). In contrast, CMR measurements of corresponding RV free wall paracardial adipose thickness did not correlate with ex vivo paracardial mass (R2 = 0.003, p = 0.878). Conclusion In this ovine model, CMR-derived paracardial adipose tissue volume, but not the corresponding and conventional measure of paracardial adipose thickness over the RV free wall, accurately reflected paracardial adipose tissue mass. This study validates for the first time, the use of clinically utilised CMR sequences for the accurate and reproducible assessment of pericardial adiposity. Furthermore this non-invasive modality does not use ionising radiation and therefore is ideally suited for future studies of PAT and its role in cardiovascular risk prediction and disease in clinical practice.

Abstract Background Percutaneous closure of atrial septal defects (ASDs) should potentially reduce right heart volumes by removing left-to-right shunting. Due to ventricular interdependence, this may be associated with impaired left ventricular filling and potentially function. Furthermore, atrial changes post-ASD closure have been poorly understood and may be important for understanding risk of atrial arrhythmia post-ASD closure. Cardiovascular magnetic resonance (CMR) is an accurate and reproducible imaging modality for the assessment of cardiac function and volumes. We assessed cardiac volumes pre- and post-percutaneous ASD closure using CMR. Methods Consecutive patients (n = 23) underwent CMR pre- and 6 months post-ASD closure. Steady state free precession cine CMR was performed using contiguous slices in both short and long axis views through the ASD. Data was collected for assessment of left and right atrial, ventricular end diastolic volumes (EDV) and end systolic volumes (ESV). Data is presented as mean ± SD, volumes as mL, and paired t-testing performed between groups. Statistical significance was taken as p < 0.05. Results There was a significant reduction in right ventricular volumes at 6 months post-ASD closure (RVEDV: 208.7 ± 76.7 vs. 140.6 ± 60.4 mL, p < 0.0001) and RVEF was significantly increased (RVEF 35.5 ± 15.5 vs. 42.0 ± 15.2%, p = 0.025). There was a significant increase in the left ventricular volumes (LVEDV 84.8 ± 32.3 vs. 106.3 ± 38.1 mL, p = 0.003 and LVESV 37.4 ± 20.9 vs. 46.8 ± 18.5 mL, p = 0.016). However, there was no significant difference in LVEF and LV mass post-ASD closure. There was a significant reduction in right atrial volumes at 6 months post-ASD closure (pre-closure 110.5 ± 55.7 vs. post-closure 90.7 ± 69.3 mL, p = 0.019). Although there was a trend to a decrease in left atrial volumes post-ASD closure, this was not statistically significant (84.5 ± 34.8 mL to 81.8 ± 44.2 mL, p = NS). Conclusion ASD closure leads to normalisation of ventricular volumes and also a reduction in right atrial volume. Further follow-up is required to assess how this predicts outcomes such as risk of atrial arrhythmias after such procedures.