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Xiaoqing Wang, Arun A Joseph, Oleksandr Kalentev, K Dietmar Merboldt, Dirk Voit, Volkert B Roeloffs, Maaike van Zalk, Jens Frahm
OBJECTIVE: To develop a novel method for rapid myocardial T1 mapping at high spatial resolution. METHODS: The proposed strategy represents a single-shot inversion-recovery (IR) experiment triggered to early diastole during a brief breathhold. The measurement combines an adiabatic inversion pulse with a real-time readout by highly undersampled radial FLASH, iterative image reconstruction and T1 fitting with automatic deletion of systolic frames. The method was implemented on a 3 T MRI system using a GPU-equipped bypass computer for online application...
October 19, 2016: British Journal of Radiology
Yuko Y Inoue, Bharath Ambale-Venkatesh, Nathan Mewton, Gustavo J Volpe, Yoshiaki Ohyama, Ravi K Sharma, Colin O Wu, Chia-Ying Liu, David A Bluemke, Elsayed Z Soliman, João A C Lima, Hiroshi Ashikaga
Purpose To examine the associations of myocardial diffuse fibrosis and scar with surface electrocardiographic (ECG) parameters in individuals free of prior coronary heart disease in four different ethnicities. Materials and Methods This prospective cross-sectional study was approved by the institutional review boards, and all participants gave informed consent. A total of 1669 participants in the Multi-Ethnic Study of Atherosclerosis, or MESA, who were free of prior myocardial infarction underwent both ECG and cardiac magnetic resonance imaging...
October 13, 2016: Radiology
Neville D Gai, Ashkan A Malayeri, David A Bluemke
PURPOSE: To develop and assess a new technique for three-dimensional (3D) full lung T1 and T2* mapping using a single free breathing scan during a clinically feasible time. MATERIALS AND METHODS: A 3D stack of dual-echo ultrashort echo time (UTE) radial acquisition interleaved with and without a WET (water suppression enhanced through T1 effects) saturation pulse was used to map T1 and T2* simultaneously in a single scan. Correction for modulation due to multiple views per segment was derived...
October 11, 2016: Journal of Magnetic Resonance Imaging: JMRI
Gopal Nataraj, Jon-Fredrick Nielsen, Jeffrey Fessler
Rapid, reliable quantification of MR relaxation parameters T1 and T2 is desirable for many clinical applications. Steady-state sequences such as Spoiled Gradient-Recalled Echo (SPGR) and Dual-Echo Steady-State (DESS) are fast and wellsuited for relaxometry because the signals they produce are quite sensitive to T1 and T2 variation. However, T1, T2 estimation with these sequences typically requires multiple scans with varied sets of acquisition parameters. This paper describes a systematic framework for selecting scan types (e...
October 4, 2016: IEEE Transactions on Medical Imaging
Tiago Teixeira, Tarik Hafyane, Nikola Stikov, Cansu Akdeniz, Andreas Greiser, Matthias G Friedrich
BACKGROUND: T1 mapping based on cardiovascular magnetic resonance (CMR) is a novel approach using the magnetic relaxation T1 time as a quantitative marker for myocardial tissue composition. Various T1 mapping sequences are being used, with different strengths and weaknesses. Data comparing different sequences head to head however are sparse. METHODS: We compared three T1 mapping sequences, ShMOLLI, MOLLI and SASHA in phantoms and in a mid-ventricular slice of 40 healthy individuals (mean age 59 ± 7 years, 45 % male) with low (68 %) or moderate cardiovascular risk...
October 4, 2016: Journal of Cardiovascular Magnetic Resonance
Jeong Hee Yoon, Jeong Min Lee, Eunju Kim, Tomoyuki Okuaki, Joon Koo Han
Purpose To determine whether B1 inhomogeneity-corrected volumetric T1 maps of gadoxetic acid-enhanced liver magnetic resonance (MR) imaging are able to demonstrate global liver function and functional heterogeneity in patients with cirrhosis and to investigate their relationship with the development of hepatic insufficiency and decompensation. Materials and Methods This institutional review board-approved retrospective study with waiver of informed consent included 234 consecutive patients who underwent gadoxetic acid-enhanced liver MR imaging, including B1 inhomogeneity-corrected volumetric T1 mapping...
October 3, 2016: Radiology
Ursula Reiter, Gert Reiter, Martin Manninger, Gabriel Adelsmayr, Julia Schipke, Alessio Alogna, Alexandra Rajces, Aurelien F Stalder, Andreas Greiser, Christian Mühlfeld, Daniel Scherr, Heiner Post, Burkert Pieske, Michael Fuchsjäger
BACKGROUND: The hypertensive deoxy-corticosterone acetate (DOCA)-salt-treated pig (hereafter, DOCA pig) was recently introduced as large animal model for early-stage heart failure with preserved ejection fraction (HFpEF). The aim of the present study was to evaluate cardiovascular magnetic resonance (CMR) of DOCA pigs and weight-matched control pigs to characterize ventricular, atrial and myocardial structure and function of this phenotype model. METHODS: Five anesthetized DOCA and seven control pigs underwent 3 T CMR at rest and during dobutamine stress...
September 30, 2016: Journal of Cardiovascular Magnetic Resonance
Nick Frazier, Allison Payne, Joshua de Bever, Christopher Dillon, Apoorva Panda, Nithya Subrahmanyam, Hamidreza Ghandehari
Mild hyperthermia has been used in combination with polymer therapeutics to further increase delivery to solid tumors and enhance efficacy. An attractive method for generating heat is through non-invasive high intensity focused ultrasound (HIFU). HIFU is often used for ablative therapies and must be adapted to produce uniform mild hyperthermia in a solid tumor. In this work a magnetic resonance imaging guided HIFU (MRgHIFU) controlled feedback system was developed to produce a spatially uniform 43°C heating pattern in a subcutaneous mouse tumor...
November 10, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
David J Hur, Demetrius L Dicks, Steffen Huber, Hamid R Mojibian, Judith L Meadows, Stuart E Seropian, Lauren A Baldassarre
No abstract text is available yet for this article.
October 2016: Circulation. Cardiovascular Imaging
G E Hagberg, J Bause, T Ethofer, P Ehses, T Dresler, C Herbert, R Pohmann, G Shajan, A Fallgatter, M A Pavlova, K Scheffler
Mapping of the longitudinal relaxation time (T1) with high accuracy and precision is central for neuroscientific and clinical research, since it opens up the possibility to obtain accurate brain tissue segmentation and gain myelin-related information. An ideal, quantitative method should enable whole brain coverage within a limited scan time yet allow for detailed sampling with sub-millimeter voxel sizes. The use of ultra-high magnetic fields is well suited for this purpose, however the inhomogeneous transmit field potentially hampers its use...
September 21, 2016: NeuroImage
Gabriel Ramos-Llorden, Arnold J den Dekker, Gwendolyn Van Steenkiste, Ben Jeurissen, Floris Vanhevel, Johan Van Audekerke, Marleen Verhoye, Jan Sijbers
In quantitative MR T1 mapping, the spin-lattice relaxation time T1 of tissues is estimated from a series of T1- weighted images. As the T1 estimation is a voxel-wise estimation procedure, correct spatial alignment of the T1-weighted images is crucial. Conventionally, the T1-weighted images are first registered based on a general-purpose registration metric, after which the T1 map is estimated. However, as demonstrated in this paper, such a two-step approach leads to a bias in the final T1 map. In our work, instead of considering motion correction as a preprocessing step, we recover the motion-free T1 map using a unified estimation approach...
September 20, 2016: IEEE Transactions on Medical Imaging
Paul Wexberg, Marion Avanzini, Julia Mascherbauer, Stefan Pfaffenberger, Birgit Freudenthaler, Reginald Bittner, Günther Bernert, Franz Weidinger
BACKGROUND: Duchenne muscular dystrophy (DMD) is an X-linked recessive disease that occurs in males leading to immobility and death in early adulthood. Female carriers of DMD are generally asymptomatic, yet frequently develop dilated cardiomyopathy. This study aims to detect early cardiac manifestation in DMD using cardiovascular magnetic resonance (CMR) and to evaluate its association with clinical symptoms. METHODS: Clinical assessment of DMD carriers included six minutes walk tests (6MWT), blood analysis, electrocardiography, echocardiography, and CMR using FLASH sequences to detect late gadolinium enhancement (LGE)...
2016: Journal of Cardiovascular Magnetic Resonance
Gabriella Captur, Peter Gatehouse, Kathryn E Keenan, Friso G Heslinga, Ruediger Bruehl, Marcel Prothmann, Martin J Graves, Richard J Eames, Camilla Torlasco, Giulia Benedetti, Jacqueline Donovan, Bernd Ittermann, Redha Boubertakh, Andrew Bathgate, Celine Royet, Wenjie Pang, Reza Nezafat, Michael Salerno, Peter Kellman, James C Moon
BACKGROUND: T1 mapping and extracellular volume (ECV) have the potential to guide patient care and serve as surrogate end-points in clinical trials, but measurements differ between cardiovascular magnetic resonance (CMR) scanners and pulse sequences. To help deliver T1 mapping to global clinical care, we developed a phantom-based quality assurance (QA) system for verification of measurement stability over time at individual sites, with further aims of generalization of results across sites, vendor systems, software versions and imaging sequences...
2016: Journal of Cardiovascular Magnetic Resonance
Vassilios S Vassiliou, Ee Ling Heng, Peter D Gatehouse, Jacqueline Donovan, Claire E Raphael, Shivraman Giri, Sonya V Babu-Narayan, Michael A Gatzoulis, Dudley J Pennell, Sanjay K Prasad, David N Firmin
BACKGROUND: Magnetic resonance imaging (MRI) phantoms are routinely used for quality assurance in MRI centres; however their long term stability for verification of myocardial T1/ extracellular volume fraction (ECV) mapping has never been investigated. METHODS: Nickel-chloride agarose gel phantoms were formulated in a reproducible laboratory procedure to mimic blood and myocardial T1 and T2 values, native and late after Gadolinium administration as used in T1/ECV mapping...
2016: Journal of Cardiovascular Magnetic Resonance
Keyur Parekh, Michael Markl, Jie Deng, Roger A de Freitas, Cynthia K Rigsby
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...
September 22, 2016: International Journal of Cardiovascular Imaging
Markus Schwaiger, Karl Kunze, Christoph Rischpler, Stephan G Nekolla
After the successful introduction of PET/CT as a multimodality imaging technique, PET/MR has subsequently emerged as an attractive instrumentation for applications in neurology, oncology, and cardiology. Simultaneous data acquisition combining structural, functional, and molecular imaging provides a unique platform to link various aspects of cardiac performance for the non-invasive characterization of cardiovascular disease phenotypes. Specifically, tissue characterization by MR techniques with and without contrast agents allows for functional parameters such as LGE, myocardial perfusion, and T1 maps as well as an estimate of extracellular volume...
September 22, 2016: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
Jihye Jang, Steven Bellm, Sébastien Roujol, Tamer A Basha, Maryam Nezafat, Shingo Kato, Sebastian Weingärtner, Reza Nezafat
Cardiac T1 mapping allows non-invasive imaging of interstitial diffuse fibrosis. Myocardial T1 is commonly calculated by voxel-wise fitting of the images acquired using balanced steady-state free precession (SSFP) after an inversion pulse. However, SSFP imaging is sensitive to B1 and B0 imperfection, which may result in additional artifacts. A gradient echo (GRE) imaging sequence has been used for myocardial T1 mapping; however, its use has been limited to higher magnetic field to compensate for the lower signal-to-noise ratio (SNR) of GRE versus SSFP imaging...
October 2016: NMR in Biomedicine
Fritz C Roller, Christoph Wiedenroth, Andreas Breithecker, Christoph Liebetrau, Eckhard Mayer, Christian Schneider, Andreas Rolf, Christian Hamm, Gabriele A Krombach
OBJECTIVES: The aim of this study was to assess septal and right ventricular insertion point (RVIP) fibrosis in patients with chronic thromboembolic pulmonary hypertension (CTEPH) via native T1 mapping and extracellular volume fraction (ECV) determination and to analyze correlations with functional parameters. METHODS: Imaging was performed at 1.5 Tesla in 24 patients diagnosed with CTEPH and 24 controls. T1 values were measured within the septal myocardium, the upper and lower RVIP, and the lateral wall at basal short axis section...
September 20, 2016: European Radiology
Yusuhn Kang, Ja-Young Choi, Hye Jin Yoo, Sung Hwan Hong, Heung Sik Kang
Purpose To compare the delayed gadolinium-enhanced magnetic resonance (MR) imaging of cartilage (dGEMRIC) indexes acquired with different gadolinium-based contrast agents (GBCAs), with emphasis on the difference in electrical charge, and to evaluate the feasibility of the use of GBCAs other than gadopentetate dimeglumine with a double negative charge (Gd-DTPA(2-)) as alternatives at dGEMRIC. Materials and Methods Intact porcine patellae (n = 44) were divided into four groups according to GBCA used: Gd-DTPA(2-), double negative gadobenate dimeglumine (Gd-BOPTA(2-)), single negative gadoterate meglumine (Gd-DOTA(-)), and nonionic gadobutrol (Gd-DT-DO3A)...
September 20, 2016: Radiology
Huda Mahmoud, Charlotte Buchanan, Susan T Francis, Nicholas M Selby
PURPOSE OF REVIEW: MRI can noninvasively assess the structure and function of the kidney in a single MRI scan session. This review summarizes recent advancements in functional renal MRI techniques, with a particular focus on clinical applications. RECENT FINDINGS: A number of MRI techniques now provide measures of relevance to the pathophysiology of kidney disease. Diffusion-weighted imaging, used in chronic kidney disease and renal transplantation, shows promise as a measure of renal fibrosis...
November 2016: Current Opinion in Nephrology and Hypertension
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