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Background Deep vein thrombosis (DVT) is a common but elusive illness that can lead to fatal pulmonary embolism and sudden death. Effective treatment of DVT requires accurate evaluation of thrombus distribution and stage. MRI is one of diagnostic imaging modalities for DVT, and two conventional methods are MPRAGE[1] and CE-MRV[2]. Recently, 3D T1-weighted variable-flipangle turbo spin-echo (SPACE) was proposed as a black-blood technique that permits more direct visualization of DVT[3]. However, signal suppression of tremendously slow venous blood flow remains a challenge for SPACE. The unsuppressed blood signal could be a confounder in thrombus detection[3]. We hypothesized that the 3D black-blood thrombus imaging (BTI) technique[4] that combines SPACE with DANTE black-blood preparation[5] (DANTE-SPACE) might address the above issue. Methods Experiment The IRB-approved study was performed on a 3T scanner (Siemens TimTrio, Germany). DANTE-SPACE was first optimized on 8 healthy subjects (4 F 4 M, age 25 ± 4) and then tested on 12 patients (6 F 6 M, age 52 ± 13) with DVT. The optimized parameters for DANTE included: FA 15°, pulse trains 175, RF gap 1 ms, gradient 20 mT/m. The parameters for SPACE included: 3D coronal imaging with a resolution of 1.1 × 1.1 × (1.1-1.3) mm (interpolated to 0.55 × 0.55 × [0.55-0.65] mm),TR/ TE 650/9.8 ms, turbo factor 40, GRAPPA 2, scan time ~4 min. The scan was targeted to the thrombus region that was pre-determined by ultrasound within 3 days. Conventional SPACE, MPRAGE, and CE-MRV were conducted for comparison.

Background Simultaneously optimising parameters such as LV coverage, image resolution and contrast sensitivity is difficult in first-pass perfusion (FPP). 3D FPP shows potential (1) to improve coverage, but “whole-heart” coverage demands high acceleration forcing compromises such as loss of spatial resolution. 2D FPP shows high diagnostic ability with more slices distributed over alternate-RR cycles (2), relaxing acceleration requirements. This work proposes that 3D FPP could interleave two strategies with different 3D parameters in alternate cycles, in sum approaching the full set of desired FPP properties. This work also aims to improve specificity against artefacts by imaging the same myocardium with two different interleaved 3D scans (distinct from reformatting a single 3D FPP scan). Similar confirmation strategies are often used in CMR, such as repetition with swapped phaseencode direction in late-enhancement imaging.

Utility of the signal intensity ratio of the spleen and myocardium (SMR) on T2-weighted short tau inversion recovery black-blood (T2-STIR BB) images compared to semi-quantitative analysis in patients with images with diffuse high T2 signal intensity, such as that with Takotsubo cardiomyopathy, cardiac amyloidosis, hypereosinophilic myocarditis, and apical hypertrophic cardiomyopathy Ryosuke Aoki, Takatomo Nakajima, Yosuke Nakano, Reina Tonegawa, Keiko Masuoka, Makoto Muto

Background Mouse models with mycardial infarction (MI) have been intensively used to investigate the cardiac remodeling and functional change [1,2]. MRI with ECG triggering and respiratory gating (or breath-holding) is commonly used to assess MI due to its noninvasive nature. However, the manipulations of external ECG triggering and respiratory gating are cumbersome due to the small size of mouse. To address this issue, a 3D self-gating (SG) MR technique with stack-of-stars sampling trajectories was proposed for retrospectively cardiac and respiratory-gated MI imaging in mouse models [3]. Methods: Technical Design: MR data was acquired by a T1-weighted GRE sequence with stack-of-stars sampling trajectories and a partition-first golden-angle reordering (Figure 1a). The centers of k-space lines acquired at the same angle from individual partitions were aggregated and used as an SG time point. The periodic respiratory and cardiac motions were then detected through an iterative filtering process on the SG time series according to the cardiac rate of 300~500 per minute and respiration rate of 70~110 per minute. After resorting the imaging data into appropriate cardiac and respiratory phases, motion-artifact-free were finally reconstructed. Experiments: The SG technique was preliminarily validated on 5 mice with MI induction and all MR scans were performed on a 3T scanner (Siemens Tim Trio, Germany) with a customized 4-channal mouse coil. Typical imaging parameters for the ungated GRE sequence included: flip angle = 18°, TR = 4.2 ms, TE = 2.4 ms, spatial resolution = 0.6 × 0.6 × 1.5 mm, bandwidth = 620 Hz/Pixel, partition number = 12, and a total number of 3200 projections were continuously collected, corresponding to a fixed scan time of 3 min. An amount of 0.5 ml gadolinium contrast agent with concentration of 0.5 mmol/ml (Consun Pharmaceutical Group Limited, GuangZhou, China) was injected to enhance the MI. The mice were sacrificed immediately after MRI for histological analysis and comparison to the MR results.

Histological validation of a new CMR T1-mappingbased protocol to improve accuracy for fibrosis assessment in patients with aortic stenosis Vassilis Vassiliou, Katharina Wassilew, George Asimakopoulos, Anthony de Souza, Cesare Quarto, Ee Ling Heng, Claire E Raphael, Bruce S Spottiswoode, Andreas Greiser, Evangelia Nyktari, Francisco Alpendurada, David Firmin, Andrew Jabbour, John Pepper, Dudley J Pennell, Peter Gatehouse, Sanjay Prasad

Background Left atrium (LA) size and function are powerful biomarkers of cardiovascular outcomes in many diseases. We sought to determine if the expected age-associated increase in arterial stiffness (AS) and left ventricular (LV)-LA afterload leads to corresponding effects on LA function and this can be measured with cardiovascular magnetic resonance (CMR). Additionally, we investigated the significance of these markers in asymptomatic individuals with cardiovascular risk factors (CRF).

Methods CMR perfusion imaging was performed in six canines and thirty patients at 1.5T using dual-bolus (0.005 and 0.05 mmol/kg Gd-DTPA) and dual-sequence techniques with 1RR, 90° composite pulse, 50° SSFP readout, saturation recovery 90 ms, TR 2.4 ms, TE 1.2 ms, matrix size 128 × 80. A low TE 0.6 ms, low-resolution 64 × 48 FLASH image series was also acquired. The AIF was measured from the low-dose high-resolution series (DB), the high-dose low-resolution series (DS), and the high-dose high-resolution conventional single-bolus series (SB). Myocardial time intensity curves were analyzed on a midslice based on 6 transmural sectors and quantified by model-constrained deconvolution.

Background Fabry disease is a rare X-linked condition that results in storage of sphingolipids in multiple organs including the heart. The cardiac phenotype consists mainly of conduction abnormalities, left ventricular hypertrophy (LVH) and disease progression (fibrosis, arrhythmias and heart failure). CMR LGE classically shows basal inferolateral LGE. Native T1 mapping has recently shown a low T1 likely to represent myocycte storage of fat, even when no LVH is present. We sought to understand the relationship of storage to LVH and ECG abnormalities.

To assess the global and segmental left ventricular (LV) native T1 and extracellular volume fraction (ECV) in children and young adults with hypertrophic cardiomyopathy (HCM) compared to a control cohort. The study population included 21 HCM patients (mean 14.1 ± 4.6 years) and 21 controls (mean 15.7 ± 1.5 years). Native modified Look-Locker inversion recovery sequence was performed before and after contrast injection in 3 short axis planes. Global and segmental LV native T1 and ECV were quantified and compared between HCM patients and controls. Mean native T1 in HCM patients and controls was 1020.4 ± 41.2 and 965.6 ± 30.2 ms respectively (p < 0.0001). Hypertrophied myocardium had significantly higher native global T1 and global ECV compared to non-hypertrophied myocardium in HCM (p < 0.0001, = 0.14 and 0.048, = 0.01 respectively). In a subset of patients, ECV was higher in LV segments with LGE compared to no LGE (p < 0.0001). No significant correlation was identified between global native T1 and ECV and parameters of LV structure and function. Native T1 cut-off of 987 ms provided the highest sensitivity (95 %) and specificity (91 %) to separate HCM patients from controls. Global and segmental native T1 are elevated in HCM patients. LV segments with hypertrophy and/or LGE had higher ECV in a subset of HCM patients. LV native T1 and ECV do not correlate with parameters of LV structure and function. T1 in children and young adults may be used as a non-invasive tool to assess for HCM and related fibrosis.

Background Hypoxia induces pulmonary vasoconstriction leading to an increase in pulmonary vascular resistance and acute pulmonary hypertension (PH). It is known that with acute hypoxia, cardiac output (CO) is maintained with an increase in heart rate (HR) but a blunted stroke volume (SV) response. To our knowledge, the response of the healthy heart to acute pulmonary hypertension has not been studied using exercise cardiac magnetic resonance imaging (CMR). CMR is a highly reproducible and accurate method of evaluating biventricular function during exercise and can be used to measure real time physiological response to an increased cardiovascular workload. We aimed to study the ability of exercise magnetic resonance imaging to detect changes in right ventricular (RV) and left ventricular (LV) function during normoxic and hypoxic exercise.

Background In current practice, the diagnostic yield of endomyocardial biopsy is low because the procedure is performed ‘blind’ using X-ray fluoroscopy guidance and because many pathologies affect the myocardium in a patchy distribution. We hypothesized that biopsy performed under direct realtime MRI guidance would have superior diagnostic yield, in an animal model of focal myocardium pathology.

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Methods We analyzed 17 mice divided in 5 groups : 4 wild mice, 4 heterozygous for NKx2.5 allele, 2 homozygous at D1011 of embryonic age (trabeculation stage in mice), 4 homozygous at D13-14 of embryonic age (compaction stage in mice), 3 homozygous after birth. MRI scans were performed 60 days after birth with a preclinical 11.75 T MR system. High resolution cine imaging in small axis view, at the mid base-apex axis was performed. Segmentation of compacted (C) and non-compacted (NC) mass was performed with a semiautomatic software. Papillary muscles were segmented using semi-automatic thresholding and included in the compacted mass. Blood was removed from trabeculae using the same threshold tool. 4 Mice were sacrified and the whole heart was removed and sectioned in the transversal axis. Then immunofluorescence staining was performed on sections at the mid ventricular level corresponding to the image acquired in the short axis by MRI imaging to better delineate C and NC mass. Histological images were manually analysed using ImageJ to validate our method. All values are presented as median. Interexamination reproducibility was assessed using Bland-Altman analysis (BA) and by computing the correlation coefficient. Differences between groups were assessed using a Kruskall Wallis test or Mann Whitney U test when appropriate. Results were considered significant with a p < 0.05.

Background Hemorrhage is a frequent complication in acute myocardial infarction (AMI) and is speculated to be an independent predictor of adverse outcomes [1]. In addition to infarct zone remodeling, the distal remote myocardium may experience alterations vasodilator dysfunction, edema, and extracellular matrix (ECM) expansion [2-4]. The aim of our study was to understand the impact of hemorrhage on infarct as well as remote myocardial remodeling following an ischemic event. To this end, we employed quantitative T1 and T2 mapping to probe the underlying tissue alterations in a novel hemorrhagic model of AMI.

Reyhan et al. Journal of Cardiovascular Magnetic Resonance 2015, 17(Suppl 1):Q22 http://www.jcmr-online.com/content/17/S1/Q22 WALKING POSTER PRESENTATION Open Access The effect of free-breathing on left ventricular rotational mechanics in normal subjects and patients with duchenne muscular dystrophy Meral Reyhan 2,3 , Zhe Wang 2,1* , Hyun J Kim 2 , Nancy Halnon 4 , Paul J Finn 2 , Daniel B Ennis 2,1 From 18th Annual SCMR Scientific Sessions Nice, France. 4-7 February 2015 Background Patients with Duchenne Muscular Dystrophy (DMD) develop respiratory impairment and signs and symptoms of cardiac involvement at an early age. Quantitative mea- sures of cardiac function from MRI tagging can be used to stage disease progression and monitor the response to therapy. Traditional cardiac MRI exams, however, require repeated breath holding, which places a notable burden on patients with DMD and can impart intrathoracic pressure changes that alter cardiac function. The effect of free- breathing on quantitative measure of left ventricular (LV) rotational mechanics for DMD patients is incompletely understood. Objective: To evaluate differences in LV rota- tional mechanics acquired during breath holding (BH), free-breathing with averaging (AVG), and free-breathing with respiratory bellows gating (BEL). Methods 16 healthy volunteers (1 female, 27.8±3.9 years) and 5 DMD patients (all male, 11.3±3.7 years) were scanned on a 3.0T Siemens Scanner with BH, AVG and BEL. ORI-SPAMM (Reyhan. M et. al. JMRI 2014;39(2):339- 345) was used to acquire short-axis images at the base and apex of the heart. 280-330x280-330mm field-of- view, 6mm slice thickness, 192x192 acquisition matrix, 395 Hz/pixel receiver bandwidth, TE/TR =2.33-2.39/ 4.71-4.83 ms, 8 phase encode lines per segment, 12° imaging flip angle, 8 mm tag spacing, GRAPPA 2. LV Figure 1 Mean LV twist of (A) healthy volunteers and (B) patients with DMD for breath-held (BH, solid), free-breathing with averaging (AVG, dashed), and bellows gated (BEL, dash-dotted) methods. BH LV twist is generally higher compared to AVG or BEL, especially at its peak. Radiological Sciences, University of California Los Angeles, Los Angeles, CA, USA © 2015 Reyhan et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Background Global measures of heart function, e.g. LV mass (LVM) and ejection fraction (EF), are usually measured from cine CMR images. On the other hand, regional measures of myocardial contractility are obtained from tagged images. The acquisition of both datasets consumes most of the CMR exam duration. In this study, we present a method for estimating measures of global heart function from the tagged images after applying a series of mathematical operations to remove the taglines and enhance the myocardium-blood contrast.

Background Patients with left to right shunting of blood through an atrial septal defect (ASD) have decreased exercise capacity. This study hypothesized that central factors influence exercise capacity, namely systemic and pulmonary cardiac output and right ventricular (RV) function during stress as well as left atrial pressure (LAP) and pulmonary artery pressure (PAP). Previous studies have found varying effects of stress and increased heart rate on the degree of shunting. The purpose of the study was therefore to determine if atrial shunting ratio changes during stress and examine if central factors can explain decreased exercise capacity in ASD patients. Methods Eighteen patients with ASD and 16 healthy volunteers underwent cardiac magnetic resonance at rest and during 20 µg/kg/min dobutamine infusion and 0.25-0.75 mg atropine injection, aiming for an increase in heart rate to at least 70% of age-predicted maximal pulse. Two patients could not undergo stress CMR. Cine ssfp images were used for LV and RV volumes. Flow velocity mapping of the aorta and pulmonary trunk quantified cardiac output and shunt ratio (QP/QS) at rest and during stress. Ergospirometry was used to determine peak oxygen uptake (VO2peak). LAP and PAP were invasively measured at rest at the time of transcutaneous closure of the ASD.