Angiographic correlations of patients with small vessel disease diagnosed by adenosine-stress cardiac magnetic resonance imaging

Cardiac magnetic resonance imaging (CMR) with adenosine-stress myocardial perfusion is gaining importance for the detection and quantification of coronary artery disease (CAD). However, there is little knowledge about patients with CMR-detected ischemia, but having no relevant stenosis as seen on coronary angiography (CA). The aims of our study were to characterize these patients by CMR and CA and evaluate correlations and potential reasons for the ischemic findings. 73 patients with an indication for CA were first scanned on a 1.5T whole-body CMR-scanner including adenosine-stress first-pass perfusion. The images were analyzed by two independent investigators for myocardial perfusion which was classified as subendocardial ischemia (n = 22), no perfusion deficit (n = 27, control 1), or more than subendocardial ischemia (n = 24, control 2). All patients underwent CA, and a highly significant correlation between the classification of CMR perfusion deficit and the degree of coronary luminal narrowing was found. For quantification of coronary blood flow, corrected Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) was evaluated for the left anterior descending (LAD), circumflex (LCX) and right coronary artery (RCA). The main result was that corrected TFC in all coronaries was significantly increased in study patients compared to both control 1 and to control 2 patients. Study patients had hypertension or diabetes more often than control 1 patients. In conclusion, patients with CMR detected subendocardial ischemia have prolonged coronary blood flow. In connection with normal resting flow values in CAD, this supports the hypothesis of underlying coronary microvascular impairment. CMR stress perfusion differentiates non-invasively between this entity and relevant CAD

Quantification in cardiac MRI: advances in image acquisition and processing

Cardiac magnetic resonance (CMR) imaging enables accurate and reproducible quantification of measurements of global and regional ventricular function, blood flow, perfusion at rest and stress as well as myocardial injury. Recent advances in MR hardware and software have resulted in significant improvements in image quality and a reduction in imaging time. Methods for automated and robust assessment of the parameters of cardiac function, blood flow and morphology are being developed. This article reviews the recent advances in image acquisition and quantitative image analysis in CMR

Selection of reference genes in different myocardial regions of an <it>in vivo </it>ischemia/reperfusion rat model for normalization of antioxidant gene expression

<p>Abstract</p> <p>Background</p> <p>Changes in cardiac gene expression due to myocardial injury are usually assessed in whole heart tissue. However, as the heart is a heterogeneous system, spatial and temporal heterogeneity is expected in gene expression.</p> <p>Results</p> <p>In an ischemia/reperfusion (I/R) rat model we evaluated gene expression of mitochondrial and cytoplasmatic superoxide dismutase (<it>MnSod, Cu-ZnSod</it>) and thioredoxin reductase (<it>trxr1</it>) upon short (4 h) and long (72 h) reperfusion times in the right ventricle (RV), and in the ischemic/reperfused (IRR) and the remote region (RR) of the left ventricle. Gene expression was assessed by Real-time reverse-transcription quantitative PCR (RT-qPCR). In order to select most stable reference genes suitable for normalization purposes, in each myocardial region we tested nine putative reference genes by geNorm analysis. The genes investigated were: Actin beta (<it>actb)</it>, Glyceraldehyde-3-P-dehydrogenase <it>(gapdh)</it>, Ribosomal protein L13A <it>(rpl13a)</it>, Tyrosine 3-monooxygenase <it>(ywhaz)</it>, Beta-glucuronidase <it>(gusb)</it>, Hypoxanthine guanine Phosphoribosyltransferase 1 <it>(hprt)</it>, TATA binding box protein <it>(tbp)</it>, Hydroxymethylbilane synthase <it>(hmbs)</it>, Polyadenylate-binding protein 1 <it>(papbn1</it>). According to our findings, most stable reference genes in the RV and RR were <it>hmbs/hprt </it>and <it>hmbs/tbp/hprt </it>respectively. In the IRR, six reference genes were recommended for normalization purposes; however, in view of experimental feasibility limitations, target gene expression could be normalized against the three most stable reference genes (<it>ywhaz/pabp/hmbs</it>) without loss of sensitivity. In all cases <it>MnSod </it>and <it>Cu-ZnSod </it>expression decreased upon long reperfusion, the former in all myocardial regions and the latter in IRR alone. <it>trxr1 </it>expression did not vary.</p> <p>Conclusions</p> <p>This study provides a validation of reference genes in the RV and in the anterior and posterior wall of the LV of cardiac ischemia/reperfusion model and shows that gene expression should be assessed separately in each region.</p