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"Real-time MRI"

Arno Olthoff, Per-Ole Carstens, Shuo Zhang, Eva von Fintel, Tim Friede, Joachim Lotz, Jens Frahm, Jens Schmidt
OBJECTIVE: To assess safety and feasibility of real-time (RT) MRI for evaluation of dysphagia and to compare this technique to standard assessment by flexible endoscopic evaluation of swallowing (FEES) and videofluoroscopy (VF) in a cohort of patients with inclusion body myositis (IBM). METHODS: Using RT-MRI, FEES, and VF, an unselected cohort of 20 patients with IBM was studied as index disease with a uniform dysphagia. Symptoms of IBM and dysphagia were explored by standardized tools including Swallowing-Related Quality of Life Questionnaire (SWAL-QoL), IBM Functional Rating Scale, Patient-Reported Functional Assessment, and Medical Research Council Scale...
October 21, 2016: Neurology
Sindhura Pisipati, Kyle A Smith, Kushal Shah, Koji Ebersole, Roukoz B Chamoun, Paul J Camarata
OBJECTIVE Laser interstitial thermal therapy (LITT) is used in numerous neurosurgical applications including lesions that are difficult to resect. Its rising popularity can be attributed to its minimally invasive approach, improved accuracy with real-time MRI guidance and thermography, and enhanced control of the laser. One of its drawbacks is the possible development of significant edema, which contributes to extended hospital stays and often necessitates hyperosmolar or steroid therapy. Here, the authors discuss the use of minimally invasive craniotomy to resect tissue ablated with LITT in attempt to minimize cerebral edema...
October 2016: Neurosurgical Focus
Arno Olthoff, Arun A Joseph, Matthias Weidenmüller, Blake Riley, Jens Frahm
The reduction in intraoral pressure during swallowing has previously been linked to bolus transport, although no such relation has yet been proven. The purpose of this work was to evaluate the time course of intraoral pressure during swallowing using simultaneous real-time magnetic resonance imaging (MRI) and dynamic pressure recordings. Real-time MRI based on highly undersampled radial fast low-angle shot (FLASH) and regularized nonlinear inverse reconstruction was performed at 3 T using a standard head coil and a mid-sagittal section covering the entire oral cavity...
September 30, 2016: NMR in Biomedicine
S M Zhou
No abstract text is available yet for this article.
October 1, 2016: International Journal of Radiation Oncology, Biology, Physics
Toby Rogers, Kanishka Ratnayaka, Parag Karmarkar, Adrienne E Campbell-Washburn, William H Schenke, Jonathan R Mazal, Ozgur Kocaturk, Anthony Z Faranesh, Robert J Lederman
BACKGROUND: Diagnostic yield of endomyocardial biopsy is low, particularly in disease that affects the myocardium in a non-uniform distribution. We hypothesized that real-time MRI guidance could improve the yield through targeted biopsy of focal myocardial pathology. METHODS: An animal model of focal myocardial pathology was created by infusing 3mL of fluorescent microspheres (NuFlow Hydrocoat, 15μm diameter, 5 million spheres/mL) followed by 2mL of 100% ethanol to a branch coronary artery...
August 2016: JACC. Basic to Translational Science
Piotr Walczak, Joanna Wojtkiewicz, Adam Nowakowski, Aleksandra Habich, Piotr Holak, Jiadi Xu, Zbigniew Adamiak, Moussa Chehade, Monica S Pearl, Philippe Gailloud, Barbara Lukomska, Wojciech Maksymowicz, Jeff Wm Bulte, Miroslaw Janowski
Stem cell therapy for neurological disorders reached a pivotal point when the efficacy of several cell types was demonstrated in small animal models. Translation of stem cell therapy is contingent upon overcoming the challenge of effective cell delivery to the human brain, which has a volume ∼1000 times larger than that of the mouse. Intra-arterial injection can achieve a broad, global, but also on-demand spatially targeted biodistribution; however, its utility has been limited by unpredictable cell destination and homing as dictated by the vascular territory, as well as by safety concerns...
September 12, 2016: Journal of Cerebral Blood Flow and Metabolism
Karsten Günzel, Matthias Haas, Andreas Maxeiner, Carsten Stephan, John Buckendahl, Patrick Asbach, Kurt Miller, Carsten Kempkensteffen, Hannes Cash
OBJECTIVE: Evaluating the predictive factors that enable identifying men in which a sole MRI/ultrasound (MRI/US) fusion-guided targeted biopsy (TB) detects the maximal prostate cancer (PCa) risk group. PATIENTS AND METHODS: Retrospective analysis of 251 consecutive patients who received a sensor-based, real-time MRI/US TB in combination with a 10-core systematic biopsy (SB) between August 2013 and July 2015. Univariate and multivariate binary regression analyses were performed to evaluate the predictors for equal/superior detection of the PCa risk group by TB compared to SB...
September 13, 2016: Urologia Internationalis
Megan E Poorman, Vandiver L Chaplin, Ken Wilkens, Mary D Dockery, Todd D Giorgio, William A Grissom, Charles F Caskey
BACKGROUND: MR-guided focused ultrasound or high-intensity focused ultrasound (MRgFUS/MRgHIFU) is a non-invasive therapeutic modality with many potential applications in areas such as cancer therapy, drug delivery, and blood-brain barrier opening. However, the large financial costs involved in developing preclinical MRgFUS systems represent a barrier to research groups interested in developing new techniques and applications. We aim to mitigate these challenges by detailing a validated, open-source preclinical MRgFUS system capable of delivering thermal and mechanical FUS in a quantifiable and repeatable manner under real-time MRI guidance...
2016: Journal of Therapeutic Ultrasound
Ah Young Park, Bo Kyoung Seo
Real-time magnetic resonance imaging (MRI) navigated ultrasound is an image fusion technique to display the results of both MRI and ultrasonography on the same monitor. This system is a promising technique to improve lesion detection and analysis, to maximize advantages of each imaging modality, and to compensate the disadvantages of both MRI and ultrasound. In evaluating breast cancer stage preoperatively, MRI and ultrasound are the most representative imaging modalities. However, sometimes difficulties arise in interpreting and correlating the radiological features between these two different modalities...
September 2016: Korean Journal of Radiology: Official Journal of the Korean Radiological Society
K Wachowicz, N De Zanche, E Yip, V Volotovskyy, B G Fallone
PURPOSE: This work examines the subject of contrast-to-noise ratio (CNR), specifically between tumor and tissue background, and its dependence on the MRI field strength, B0. This examination is motivated by the recent interest and developments in MRI/radiotherapy hybrids where real-time imaging can be used to guide treatment beams. The ability to distinguish a tumor from background tissue is of primary importance in this field, and this work seeks to elucidate the complex relationship between the CNR and B0 that is too often assumed to be purely linear...
August 2016: Medical Physics
Valentina Mazzoli, Aart J Nederveen, Jos Oudeman, Andre Sprengers, Klaas Nicolay, Gustav J Strijkers, Nico Verdonschot
PURPOSE: To introduce a method for obtaining fat-suppressed images in real-time MRI of moving joints at 3 Tesla (T) using a bSSFP sequence with phase detection to enhance visualization of soft tissue structures during motion. METHODS: The wrist and knee of nine volunteers were imaged with a real-time bSSFP sequence while performing dynamic tasks. For appropriate choice of sequence timing parameters, water and fat pixels showed an out-of-phase behavior, which was exploited to reconstruct water and fat images...
July 15, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
He-Lin Xu, Kai-Li Mao, Yin-Ping Huang, Jing-Jing Yang, Jie Xu, Pian-Pian Chen, Zi-Liang Fan, Shuang Zou, Zheng-Zheng Gao, Jia-Yu Yin, Jian Xiao, Cui-Tao Lu, Bao-Lin Zhang, Ying-Zheng Zhao
Multifunctional nanoparticles capable of the specific delivery of therapeutics to diseased cells and the real-time imaging of these sites have the potential to improve cancer treatment through personalized therapy. In this study, we have proposed a multifunctional nanoparticle that integrate magnetic targeting, drug-carrier functionality and real-time MRI imaging capabilities in one platform for the theranostic treatment of tumors. The multifunctional nanoparticle was designed with a superparamagnetic iron oxide core and a multifunctional shell composed of PEG/PEI/polysorbate 80 (Ps 80) and was used to encapsulate DOX...
August 7, 2016: Nanoscale
Joshua L Chan, Dumitru Mazilu, Justin G Miller, Timothy Hunt, Keith A Horvath, Ming Li
PURPOSE: Real-time magnetic resonance imaging (rtMRI) guidance provides significant advantages during transcatheter aortic valve replacement (TAVR) as it provides superior real-time visualization and accurate device delivery tracking. However, performing a TAVR within an MRI scanner remains difficult due to a constrained procedural environment. To address these concerns, a magnetic resonance (MR)-compatible robotic system to assist in TAVR deployments was developed. This study evaluates the technical design and interface considerations of an MR-compatible robotic-assisted TAVR system with the purpose of demonstrating that such a system can be developed and executed safely and precisely in a preclinical model...
October 2016: International Journal of Computer Assisted Radiology and Surgery
Matthias Echternach, Fabian Burk, Michael Burdumy, Louisa Traser, Bernhard Richter
INTRODUCTION: Dynamic MRI analysis of phonation has gathered interest in voice and speech physiology. However, there are limited data addressing the extent to which articulation is dependent on loudness. MATERIAL AND METHODS: 12 professional singer subjects of different voice classifications were analysed concerning the vocal tract profiles recorded with dynamic real-time MRI with 25fps in different pitch and loudness conditions. The subjects were asked to sing ascending scales on the vowel /a/ in three loudness conditions (comfortable=mf, very soft=pp, very loud=ff, respectively)...
2016: PloS One
Kanishka Ratnayaka, Toby Rogers, William H Schenke, Jonathan R Mazal, Marcus Y Chen, Merdim Sonmez, Michael S Hansen, Ozgur Kocaturk, Anthony Z Faranesh, Robert J Lederman
OBJECTIVES: The aim of this study was to test the hypothesis that real-time magnetic resonance imaging (MRI) would enable closed-chest percutaneous cavopulmonary anastomosis and shunt by facilitating needle guidance along a curvilinear trajectory, around critical structures, and between a superior vena cava "donor" vessel and a pulmonary artery "target." BACKGROUND: Children with single-ventricle physiology require multiple open heart operations for palliation, including sternotomies and cardiopulmonary bypass...
May 9, 2016: JACC. Cardiovascular Interventions
Jakob Klosowski, Jens Frahm
PURPOSE: To develop an image noise filter suitable for MRI in real time (acquisition and display), which preserves small isolated details and efficiently removes background noise without introducing blur, smearing, or patch artifacts. THEORY AND METHODS: The proposed method extends the nonlocal means algorithm to adapt the influence of the original pixel value according to a simple measure for patch regularity. Detail preservation is improved by a compactly supported weighting kernel that closely approximates the commonly used exponential weight, while an oracle step ensures efficient background noise removal...
April 15, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Andreia C Freitas, Marzena Wylezinska, Malcolm J Birch, Steffen E Petersen, Marc E Miquel
Dynamic imaging of the vocal tract using real-time MRI has been an active and growing area of research, having demonstrated great potential to become routinely performed in the clinical evaluation of speech and swallowing disorders. Although many technical advances have been made in regards to acquisition and reconstruction methodologies, there is still no consensus in best practice protocols. This study aims to compare Cartesian and non-Cartesian real-time MRI sequences, regarding image quality and temporal resolution trade-off, for dynamic speech imaging...
2016: PloS One
Toby Rogers, Srijoy Mahapatra, Steven Kim, Michael A Eckhaus, William H Schenke, Jonathan R Mazal, Adrienne Campbell-Washburn, Merdim Sonmez, Anthony Z Faranesh, Kanishka Ratnayaka, Robert J Lederman
BACKGROUND: Radiofrequency ablation for ventricular arrhythmias is limited by inability to visualize tissue destruction, by reversible conduction block resulting from edema surrounding lesions, and by insufficient lesion depth. We hypothesized that transcatheter needle injection of caustic agents doped with gadolinium contrast under real-time magnetic resonance imaging (MRI) could achieve deep, targeted, and irreversible myocardial ablation, which would be immediately visible. METHODS AND RESULTS: Under real-time MRI guidance, ethanol or acetic acid was injected into the myocardium of 8 swine using MRI-conspicuous needle catheters...
April 2016: Circulation. Arrhythmia and Electrophysiology
Gengsheng L Zeng, Zeljko Divkovic
Recently we developed a Bayesian-FBP (Filtered Backprojection) algorithm for CT image reconstruction. This algorithm is also referred to as the FBP-MAP (FBP Maximum a Posteriori) algorithm. This non-iterative Bayesian algorithm has been applied to real-time MRI, in which the k-space is under-sampled. This current paper investigates the possibility to extend this Bayesian-FBP algorithm by introducing more controlling parameters. Thus, our original Bayesian-FBP algorithm became a special case of the extended Bayesian-FBP algorithm...
February 2016: IEEE Transactions on Nuclear Science
Lau Brix, Steffen Ringgaard, Puk Sandager, Olav Bjørn Petersen, Thomas Sangild Sørensen, Erik Lundorf, Brian Stausbøl-Grøn
OBJECTIVE: Foetal MRI has become an established image modality in the prenatal diagnosis of CNS anomalies, but image quality can be severely affected by foetal movements. The objective was to overcome these inherent motion problems by applying interactive real-time MRI and to evaluate the diagnostic usefulness of the applied real-time MRI sequence in relation to standard protocols. METHODS: Ten healthy foetuses (gestation week 21·3 ± 0·5) were scanned using a system, which allowed visual feedback and interactive slice positioning in real time...
March 22, 2016: Clinical Physiology and Functional Imaging
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