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Background High-resolution quantitative analysis of myocardial blood flow (MBF) by cardiac magnetic resonance (CMR) perfusion has been recently proposed and validated in preclincal studies. It aims to combine the advantages of both visual assessment and quantitative analysis in a single test. However, incorrect registration between stress and rest images can hamper myocardial perfusion reserve (MPR) calculation from high-resolution perfusion maps. The aim of this study was to test the feasibility of MPR analysis from high-resolution perfusion maps as well as to test MBF threshold analysis, a novel analysis approach capable to measure the extent of ischemic myocardium with high spatial accuracy. Methods Ten patients with single-vessel coronary artery disease (CAD) and ten control subjects were analyzed at 3 Tesla. Perfusion data were analyzed on high-resolution maps and at segmental level to simulate MPR for variable degrees of image misregistration. MBF threshold analysis was then applied to high-resolution perfusion maps. In analogy to one of the methods currently in use for the quantification of late gadolinium enhancement, pixels with abnormally reduced coronary flow reserve were defined on the basis of the average MBF in areas with visually normal perfusion. In this exploratory analysis, the ischemic myocardium was defined as pixels with MBF reduced below the 90th, 95th and 99th percentile of the average epicardial MBF of the reference segment. MBF threshold analysis defines the amount of ischemic myocardium as a percentage of the LV (global ischemic burden) or of a perfusion territory (territorial ischemic burden).

Ischemic preconditioning increases the velocity of vasodilatation and reduces the total hyperemic flow (THF) of a subsequent coronary reactive hyperemia (CRH). The increase in the velocity of vasodilatation has been shown to depend on an up-regulation of the endothelial release of nitric oxide, while the reduction of THF is attributed to an adenosine A 1 receptor-mediated mechanism. We investigated whether the changes in CRH induced by preconditioning ischemia (PI) can still be obtained after blockade of mitochondrial ATP-sensitive K + channels by sodium 5-hydroxydecanoate (5-HD), and whether the blockade per se affects the pattern of CRH. In anesthetized goats, flow was recorded from the left circumflex coronary artery (LCCA). CRH was obtained with the occlusion of LCCA for 15 s. PI was obtained by 2 cycles of 2.5 min of LCCA occlusion with a 5 min interval of reperfusion between the two occlusions. CRH was studied before and after i.v. administration of 5-HD (20 mg/kg), as well as in the presence of 5-HD after PI. Following 5-HD, the pattern of CRH remained unchanged. After 5-HD and PI, velocity of vasodilatation and total hyperemic flow of CRH showed the same changes as in previous studies after PI alone. It was concluded that the blockade of mitochondrial ATP-sensitive K + channels, which is reported to prevent myocardial protection, does not affect CRH and does not prevent PI from increasing the velocity of vasodilatation and reducing THF. These results demonstrate that the changes induced in CRH by preconditioning are independent of the opening of the mitochondrial ATP-sensitive K + channels.

Background Low dose dobutamine stress magnetic resonance imaging (LDDSMR) is a widely accepted technique for assessment of hibernating myocardium in patients with ischemic cardiomyopathy (ICMP). It is particularly helpful in patients with intermediate transmurality of scar where prediction of functional recovery by late gadolinium enhancement imaging (LGE) alone is difficult. Analysis of LDDSMR is usually based on visual assessment and is therefore considerably operator dependant. Recently myocardial feature tracking (FT) has been introduced. It tracks tissue voxel motion of cine-MR images to assess circumferential and radial myocardial strain independent of additional sequences.

Increased endocardial to epicardial flow ratio present at rest disappears during exercise stress perfusion CMR in normal volunteers a potential mechanism for exercise induced subendocardial ischaemia Kaleab N Asrress, Rupert Williams, Tim Lockie, John D Biglands, Amedeo Chiribiri, Aleksandra Radjenovic, Roy Jogiya, Kalpa De Silva, Sebastian Kozerke, Phil Chowienczyk, Eike Nagel, Michael Marber, Simon Redwood, Sven Plein

Background Three-dimensional acquisition methods facilitated by undersampling in space and/or time have been proposed to overcome the limited cardiac coverage of dynamic first pass myocardial perfusion-CMR. Recently, temporally constrained k-t BLAST reconstruction using principal component analysis (k-t PCA) has been proposed to further improve temporal resolution of k-t undersampled data. In addition, multi-transmit technology has become available, which aims to improve image uniformity and SAR limitations at higher field strength. We have developed a pulse sequence for 3D perfusion-CMR that utilises both k-t PCA and multi-transmit technology at 3 Tesla.

Background Hypertrophic cardiomyopathy (HCM) has a wide clinical spectrum. An important subgroup of patients are at risk of major complications and sudden cardiac death. However risk stratification in these patients is still a challenge. The degree of hypertrophy and myocardial fibrosis are important predictors of prognosis. There are several papers showing the possibility of areas of abnormal left ventricular (LV) perfusion in patients with HCM. Some studies focused on stress-induced perfusion defects (Petersen SE, et al. Circulation 2007;115:2418-2425), demonstrating the presence of epi-endocardial gradients of perfusion in the LV due to microvascular dysfunction. Some other studies (Matsunaka T MRSM 2003;2:61-9 Melacini P, Int J Cardiol 2008;128:364-73) have focused the attention on LGE-related rest perfusion abnormalities. These are due to areas of microvascular disruption and do not contribute necessarily towards the LV ischemic burden. Mixed defects are also possible. The aim of the study was to analyse in retrospective a group of patients with HCM that underwent stress perfusion and LGE-CMR and to describe the prevalence of perfusion defects of each type.

Introduction X-Ray Angiography (XRA) is the gold standard for the assessment of lumen encroaching coronary stenosis, which typically underlies stable coronary artery disease. However, XRA cannot distinguish between stable and vulnerable plaques, which are thought to be the precursor lesions of most acute myocardial infarctions (MI) and death. The development of a non-invasive technique that can detect culprit lesions immediately after MI may eventually prove useful for prospective identification of vulnerable plaque.

Background First pass perfusion CMR is a well-validated technique for the detection of inducible myocardial ischaemia. However, limited data are available on the feasibility of first pass perfusion CMR and quantitative deconvolution analysis in the context of reduced LV function. The aim of this study was to assess effects of reduced LV function and LV dilatation on the characteristics of signal in the left ventricle (arterial input function, AIF) and in the myocardium (MSI), and to test the feasibility of quantitative perfusion analysis with Fermi deconvolution in this cohort of patients.

Methods 22 patients with known or suspected CAD underwent both N-Ammonia PET and CMR adenosine stress and rest perfusion imaging prior to diagnostic coronary Xray angiography (CXA). CMR perfusion imaging was performed at 1.5T with a kt-accelerated steady-state free-precession sequence. Data analysis was blind. A significant coronary artery stenosis was defined as at least 70% diameter reduction or a fractional flow reserve

Background Long acquisition times and complex breathing motion patterns lead to suboptimal image quality in whole heart coronary magnetic resonance angiography (WHCMRA). To overcome this problem, an abdominal belt (BELT) has been suggested by a Japanese group. However, its applicability in a Western population has not been previously demonstrated. The purpose of this study was to investigate 1) how the application of a BELT alters breathing patterns during MR scanning and 2) whether the BELT has a similar impact on breathing patterns in UK and Japanese patient populations. Methods 30 patients (15 in the UK and 15 in Japan) were studied at 1.5 Tesla (Achieva, Philips Healthcare). Real time navigator positioned through the right diaphragm in cranio-caudal direction was evaluated. Measurements were performed in the supine position with free breathing for one minute before and after a tight-fitting BELT was positioned around the patient's abdomen. End expiratory position (EEP), end inspiratory position (EIP), end expiratory duration (EED) for the right diaphragm and respiratory rate (RR) were obtained. Scan efficiency (SE) was calculated as follows; SE = [the duration within 5 mm gating window per minutes]/[RR interval]/[heart rate]. Results Height and weight of UK patients were significantly larger than in the Japanese population (171.2 ± 10.8 cm vs 160.8 ± 8.5 cm, p = 0.007; 80.5 ± 22.5 kg vs 59.9 ± 7.7 kg, p = 0.004). After fitting the BELT, EEP-EIP decreased (all patients, 14.9 ± 6.2 mm to 9.4 ± 3.8 mm, p < 0.001; UK patients, 15.9 ± 6.0 mm to 9.7 ± 3.1 mm, p = 0.001; Japanese patients, 14.0 ± 6.4 mm to 9.1 ± 4.6 mm, p = 0.001), RR increased (all patients, 10.0 ± 3.1 min-1 to 11.2 ± 3.0 min-1, p = 0.003; UK patients, 9.5 ± 2.8 min-1 to 10.7 ± 2.8 min-1, p = 0.038; Japanese patients, 10.4 ± 3.5 min-1 to 11.8 ± 3.1 min-1, p = 0.036), and calculated scan efficiency increased (all patients, 45.3 ± 11.4% to 58.6 ± 17.0%, p < 0.001; UK patients, 44.2 ± 10.8% to 55.7 ± 16.7%, p = 0.004; Japanese patients, 46.3 ± 32.2% to 61.0 ± 17.6%, p = 0.001). No significant differences were found between UK and Japanese patients before and after administration of the BELT. Conclusion Using a BELT significantly increases whole-heart coronary MR angiography scan efficiency in both UK and Japanese patients.

Background Dynamic first pass contrast-enhanced myocardial perfusion is the standard CMR method for the estimation of myocardial blood flow (MBF) and MBF reserve in man, but it is challenging in rodents because of the high temporal and spatial resolution requirements. Hyperemic first pass myocardial perfusion CMR during vasodilator stress in mice has not been reported. Methods Five C57BL/6 J mice were scanned on a clinical 3.0 Tesla Achieva system (Philips Healthcare, Netherlands). Vasodilator stress was induced via a tail vein catheter with an injection of dipyridamole. Dynamic contrast-enhanced perfusion imaging (Gadobutrol 0.1 mmol/kg) was based on a saturation recovery spoiled gradient echo method with 10-fold k-space and time domain undersampling (k-t PCA). One week later the mice underwent repeat anaesthesia and LV injections of fluorescent microspheres at rest and at stress. Microspheres were analysed using confocal microscopy and fluorescence-activated cell sorting. Results Mean MBF at rest measured by Fermi-function constrained deconvolution was 4.1 ± 0.5 ml/g/min and increased to 9.6 ± 2.5 ml/g/min during dipyridamole stress (P = 0.005). The myocardial perfusion reserve was 2.4 ± 0.54. The mean count ratio of stress to rest microspheres was 2.4 ± 0.51 using confocal microscopy and 2.6 ± 0.46 using fluorescence. There was good agreement between cardiovascular magnetic resonance CMR and microspheres with no significant difference (P = 0.84). Conclusion First-pass myocardial stress perfusion CMR in a mouse model is feasible at 3 Tesla. Rest and stress MBF values were consistent with existing literature and perfusion reserve correlated closely to microsphere analysis. Data were acquired on a 3 Tesla scanner using an approach similar to clinical acquisition protocols, potentially facilitating translation of imaging findings between rodent and human studies.

Methods Clinical data and DCMR results were analyzed in 1466 consecutive patients undergoing DCMR between 2000 and 2004. Ninety four patients lost to follow-up and three hundred fifty five patients who underwent early revascularization within 3 months of DCMR were excluded from analysis. The remaining 1017 patients (median age, 62 years) were followed up for a mean of 44 ± 24 months (range: 1 to 116 months). Wall motion abnormalities (WMA) at rest and the presence of stress-induced WMA (ischemia) were assessed for each patient. Cardiac events, defined as cardiac death and non-fatal myocardial infarction, were related to clinical and DCMR results. Patients with inducible WMA were compared in regards to following therapy (revascularization or medical therapy alone) and outcome.

Background Excess of cardiovascular (CV) morbidity and mortality in RA patients is not fully explained by traditional CV risk factors. Evidence suggests the presence of inflammation-induced vascular and myocardial injury and dysfunction, leading to premature atherosclerosis and heart failure. Aortic stiffness, an independent predictor of cardiac events and a marker of pulsatile LV afterload, improves with anti-tumor necrosis factor-alpha (antiTNF) therapy in these patients; however, the effects on determinants of systolic function remain undetermined.

Summary We aimed to determine the prognostic value of wall motion assessment during high-dose dobutamine stress cardiac magnetic resonance imaging (DCMR) for the prediction of hard cardiac events in a large patient cohort and within a long follow-up duration. DCMR can accurately identify between patients with inducible ischemia who are at increased risk for future hard cardiac events and revascularization procedures. Within the ‘primary warranty time’ of 3 years after DCMR excellent outcomes (annual hard cardiac event rate 90 days after the MR-scans were prospectively collected at least 6 months after DCMR. Results