ISMRM 24th Annual Meeting & Exhibition • 07-13 May 2016 • Singapore

Scientific Session: Myocardial Tissue Characterisation

Wednesday, May 11, 2016
Room 334-336
10:00 - 12:00
Moderators: Mehmet Akcakaya, Daniel Kim

A Joint Image Denoising Approach for Improved Precision and Accuracy in Myocardial T1 Mapping
Aurelien Bustin1,2,3, Pauline Ferry3, Andrei Codreanu4, Anne Menini2, and Freddy Odille3,5,6
1Department of Computer Science, Technische Universität München, Munich, Germany, 2GE Global Research, Munich, Germany, 3Imagerie Adaptative Diagnostique et Interventionnelle, Universite de Lorraine, Nancy, France, 4Centre Hospitalier de Luxembourg, Luxembourg, Luxembourg, 5CIC-IT 1433, INSERM, Nancy, France, 6U947, INSERM, Nancy, France
To improve precision and accuracy in myocardial T1 mapping by combining saturation-recovery acquisitions with a joint denoising method. The proposed method is shown to improve mapping techniques by exploiting the spatiotemporal correlations in the native T1-weighted images, thus providing a promising tool for the measurement of myocardial and blood T1 times.

Detecting diffuse cardiac fibrosis with T1? MRI
Joep van Oorschot1, Fatih Guclu2, Peter Luijten1, Tim Leiner1, and Jaco Zwanenburg1
1Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 2Cardiology, University Medical Center Utrecht, Utrecht, Netherlands
Native T1ρ-mapping is a promising non-contrast enhanced method for fibrosis detection, that would overcome problems associated with contrast agent use. In this work, we will evaluate the performance of T1ρ-mapping versus ECV-m and native T1 in DCM patients. Native T1, native T1ρ and Contrast enhanced T1-maps were acquired in twelve DCM patients, and 8 healthy volunteers. The T1ρ relaxation time was significantly higher in the DCM patients (55.6 ± 3.0 ms), compared to the healthy control subjects (51.5 ± 1.2 ms), p<0.005. A significant correlation was found between the T1ρ relaxation time and the Extracellular Volume fraction in patients.

Improved myocardial T1 mapping technique to eliminate device-induced image artefacts for patients with implanted cardiac devices
Jiaxin Shao1, Shams Rashid1, Kim-Lien Nguyen2,3, and Peng Hu1,4
1UCLADepartment of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, United States, 2Department of Medicine, Division of Cardiology, David Geffen School of Medicine, University of California, Los Angeles, CA, United States, 3Division of Cardiology, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States, 4Biomedical Physics Inter-Departmental Graduate Program, University of California, Los Angeles, CA, United States
Current cardiac T1 mapping techniques, including the modified Look-Locker inversion-recovery (MOLLI), cannot be used effectively in patients with implanted cardiac devices due to large off-resonance induced by the device. To eliminate the device-induced image artefacts, we developed a technique by modifying the MOLLI sequence to use spoiled gradient echo readout and a wideband inversion pulse, with a new acquisition scheme and T1 estimation algorithm. The feasibility of our new technique was tested in phantom studies and validated in eight healthy volunteers and ten patients with implanted cardiac devices at 1.5 Tesla.

T2 mapping for non-invasive assessment of acute cardiac allograft rejection in a mouse model of heterotopic heart transplantation - Permission Withheld
Dagmar Hartung1,2, Rongjun Chen3, Marcel Gutberlet1,2, Song Rong3, Mi-Sun Jang3, Jan Hinrich Braesen4, Martin Meier2,5, Hermann Haller3, Frank Wacker1,2, Faikah Gueler3, and Hueper Katja1,2
1Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany, 2Rebirth, Hannover, Germany, 3Clinic for Nephrology, Hannover Medical School, Hannover, Germany,4Institute for Pathology, Hannover Medical School, Hannover, Germany, 5Imaging Center of the Central Animal Laboratory, Hannover Medical School, Hannover, Germany
Acute cardiac allograft rejection is a frequent and life-threatening complication during the first year after heart transplantation (HTx) and therefore early detection is most important. The standard of care for HTx recipients is periodic rejection surveillance by endomyocardial biopsy. We investigated whether T2 mapping allows non-invasive detection of acute cardiac allograft rejection in mice. We demonstrated that myocardial T2 is significantly increased in allogenic HTx compared to isogenic HTx mice on day 6 after transplantation likely reflecting myocardial edema and corresponds to the extent of T cell infiltration. Thus, non-invasive T2 mapping might enable early and non-invasive detection of acute cardiac allograft rejection. 

Slice accelerated Double-Inversion Radial Fast-Spin-Echo for myocardial black-blood MRI with T2 mapping
Mahesh Bharath Keerthivasan1, Sagar Mandava1, Kevin Johnson2, Diego R Martin3, Ali Bilgin1,3,4, and Maria I Altbach3
1Electrical and Computer Engineering, University of Arizona, Tucson, AZ, United States, 2Siemens Healthcare, Tucson, AZ, United States, 3Medical Imaging, University of Arizona, Tucson, AZ, United States,4Biomedical Engineering, University of Arizona, Tucson, AZ, United States
A technique to increase slice coverage in dark blood fast spin echo sequences by a multi-band excitation is presented. The proposed technique can acquire multiple slices at the exact null point of blood. The radial version of the single slice sequence can generate black blood images, TE images and T2 maps within a single breath-hold. In this work we present a model based reconstruction to generate TE images and T2 maps for upto 4 slices in a single breath-hold.

MRI Assessment of Coronary Endothelial Function using Native T1 Mapping with Nitric Oxide Synthase (NOS) Inhibition - Permission Withheld
Sophia Xinyuan Cui1 and Frederick H. Epstein1,2
1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2Radiology, University of Virginia, Charlottesville, VA, United States
Endothelial nitric oxide synthase (eNOS)-mediated production of NO is an important system regulating the microvasculature, controlling both vessel diameter and permeability.  We hypothesized that T1 mapping of the heart during NOS inhibition could detect increased water content resulting from increased microvascular permeability, providing a novel means to noninvasively probe eNOS regulation of the coronary microvasculature.  T1-mapping in mice after intravenous NOS inhibition detected an increase in myocardial T1 of 113±15 ms compared to baseline (p<0.05).  These methods are likely probing eNOS regulation of coronary microvascular permeability, which may represent a novel means of assessing the health of the coronary endothelium.    

Accuracy of cardiac magnetic resonance T1 mapping for detecting diffuse myocardial fibrosis: comprehensive comparison with the pathology in diabetic rabbits
Mu Zeng1, Nan Zhang1, Yi He1, Jing An2, Andreas Greiser3, and Zhanming Fan1
1Radiology, Beijing Anzhen Hospital,Capital medical university, Beijing, China, People's Republic of, 2MR Collaborations NE Asia, Siemens Healthcare, Beijing, China, Beijing, China, People's Republic of, 3Siemens AG Healthcare Sector MR, Erlangen, Germany
In recent years, use of the MRI T1 mapping technique to detect diffuse myocardial fibrosis has received increasing attention. Although previous studies have verified the relationship between T1 mapping and pathological findings, our study is the first to show continuity during the observation of a single disease while avoiding interference caused by other diseases. In addition, the pathology can be fully verified in real time using animal experiments. 

The main findings of this study were that (1) the ECV obtained from the MRI T1 mapping sequence was highly correlated with the CVF in terms of the degree of histologically diffuse interstitial fibrosis; (2) the correlation between the native T1 value and the CVF change was not strong; and (3) the rabbit is a suitable model for cardiac magnetic resonance research using clinical equipment.

Oxygen-enhanced T2* cardiac magnetic resonance imaging in cardiomyopathy - Permission Withheld
Satoshi Kawanami1, Michinobu Nagao1, Yuzo Yamasaki2, Takeshi Kamitani2, Torahiko Yamanouchi2, Tomomi Ide3, Ryohei Funatsu4, Hidetake Yabuuchi5, Yuji Watanabe1, and Hiroshi Honda2
1Molecular Imaging & Diagnosis, Kyushu University, Graduate School of Medical Sciences, Fukuoka, Japan, 2Clinical Radiology, Kyushu University, Graduate School of Medical Sciences, Fukuoka, Japan,3Cardiovascular Medicine, Kyushu University, Graduate School of Medical Sciences, Fukuoka, Japan, 4Radiological Technology, Kyushu University Hospital, Fukuoka, Japan, 5Health Sciences, Kyushu University, Graduate School of Medical Sciences, Fukuoka, Japan
In this study, we analyzed T2* value in the mid-left ventricular septum avid normoxia (T2*air) and hyperoxia (T2*oxy) in cases with normal, hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). Oxygen-enhanced T2* cardiac magnetic resonance (CMR) showed the different delta T2* (T2*oxy – T2* air), reflecting myocardial blood-oxygen dependent (BOLD) effect. Oxygen-enhanced T2* CMR has potential to open up a new avenue for the study of the pathophysiology of cardiomyopathy. The ΔT2* was prolonged in DCM, stable in control and shortened in HCM, respectively. Oxygen-enhanced T2* CMR can assess the oxygen metabolism in the mid-left ventricular septum with various density of capillaries and myocardial cells. We also note the relationship between T2* value and late gadolinium enhancement (LGE) or left ventricular ejection fraction (LVEF).

Myocardial extracellular volume fraction (ECV) quantified by T1 mapping can detect diffuse myocardial fibrosis in dilated cardiomyopathy (DCM): Comparison with histological collagen volume fraction by endomyocardial biopsy (EMB)
Yoshiaki Morita1, Naoaki Yamada1, Emi Tateishi2, Teruo Noguchi2, Masahiro Higashi1, and Hiroaki Naito1
1Department of Radiology, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan, 2Division of Cardiology, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
Diffuse interstitial fibrosis is frequently observed in dilated cardiomyopathy (DCM). A non-invasive method that could reliably quantify fibrosis would be preferable. In this study, we demonstrated that the T1-map-derived ECV reflects the myocardial collagen volume fraction in DCM. Therefore, the ECV could be a useful and practical biomarker for the detection of diffuse interstitial fibrosis that is difficult to evaluate using only conventional LGE images.

Assessment of Necrosis in the Ischemic Heart using Hyperpolarized [1,4-13C2]Fumarate
Damian J Tyler1, Angus Lau1, Ferdia Gallagher2, and Marie A Schroeder1
1DPAG, University of Oxford, Oxford, United Kingdom, 2Radiology, University of Cambridge, Cambridge, United Kingdom
The aim of this study was to evaluate the potential of hyperpolarised [1, 4-13C2]fumarate, coupled with MRS, to measure cardiac necrosis during ischemia and reperfusion. Hyperpolarised [1, 4-13C2]fumarate was infused into rat hearts at three time points, corresponding with the healthy heart, early reperfusion after a 20 min ischemic period, and late reperfusion. The amount of [1, 4-13C2]malate production was measured using MRS and quantified to reflect degree of cardiomyocyte necrosis. We observed a 3.8-fold increase in [1,4-13C2]malate during the late reperfusion period but no change in early reperfusion, suggesting that necrotic cell death takes place during reperfusion only. This technique shows potential to evaluate therapies targeting necrosis to prevent cardiac remodeling into failure.

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