scholarly journals MRI Powered and Triggered Current Stimulator for Concurrent Stimulation and MRI

2019 ◽  
Author(s):  
Ranajay Mandal ◽  
Nishant Babaria ◽  
Jiayue Cao ◽  
Kun-Han Lu ◽  
Zhongming Liu
Keyword(s):  
Scale Up ◽  
Small Animal ◽  
7 Tesla ◽  
Planar Imaging ◽  
Novel Device ◽  
Peripheral Muscle ◽  
Gradient Fields ◽  
Magnetic Resonance Imaging Mri ◽  
Small Animal Mri ◽  
Echo Planar

AbstractBioelectric stimulation during concurrent magnetic resonance imaging (MRI) is of interest to basic and translational studies. However, existing stimulation systems often interfere with MRI, are difficult to use or scale up, have limited efficacy, or cause safety concerns. To address these issues, we present a novel device capable of supplying current stimulation synchronized with MRI while being wirelessly powered by the MRI gradient fields. Results from testing it with phantoms and live animals in a 7 Tesla small-animal MRI system suggest that the device is able to harvest up to 72 (or 18) mW power during typical echo-planar imaging (or fast low angle shot imaging) and usable for stimulating peripheral muscle or nerve to modulate the brain or the gut, with minimal effects on MRI image quality. As a compact and standalone system, the plug-and-play device is suitable for animal research and merits further development for human applications.

scholarly journals An Optimized Registration Workflow and Standard Geometric Space for Small Animal Brain Imaging

2019 ◽  
Author(s):  
Horea-Ioan Ioanas ◽  
Markus Marks ◽  
Valerio Zerbi ◽  
Mehmet Fatih Yanik ◽  
Markus Rudin
Keyword(s):  
Small Animal ◽  
Work Flow ◽  
Imaging Data ◽  
Reference Space ◽  
Geometric Space ◽  
Scientific Results ◽  
Magnetic Resonance Imaging Mri ◽  
Small Animal Mri ◽  
High Level ◽  
Automated Quality Control

AbstractThe reliability of scientific results critically depends on reproducible and transparent data processing. Cross-subject and cross-study comparability of imaging data in general, and magnetic resonance imaging (MRI) data in particular, is contingent on the quality of registration to a standard reference space. In small animal MRI this is not adequately provided by currently used processing workflows, which utilize high-level scripts optimized for human data, and adapt animal data to fit the scripts, rather than vice-versa. In this fully reproducible article we showcase a generic work-flow optimized for the mouse brain, alongside a standard reference space suited to harmonize data between analysis and operation. We present four separate metrics for automated quality control (QC), and a visualization method to aid operator inspection. Benchmarking this workflow against common legacy practices reveals that it performs more consistently, better preserves variance across subjects while minimizing variance across sessions, and improves both volume and smoothness conservation RMSE approximately 2-fold. We propose this open source workflow and the QC metrics as a new standard for small animal MRI registration, ensuring work-flow robustness, data comparability, and region assignment validity, all of which are indispensable prerequisites for the comparability of scientific results across experiments and centers.

A thermometry software tool for monitoring laser-induced interstitial thermotherapy

2019 ◽  
Vol 64 (4) ◽  
pp. 449-457 ◽  
Author(s):  
Babak Bazrafshan ◽  
Ahmad Koujan ◽  
Frank Hübner ◽  
Christian Leithäuser ◽  
Norbert Siedow ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Software Tool ◽  
Biological Tissues ◽  
Planar Imaging ◽  
Imaging Sequence ◽  
Mri Thermometry ◽  
Visualization Toolkit ◽  
Magnetic Resonance Imaging Mri ◽  
Echo Planar ◽  
Interstitial Thermotherapy

Abstract The purpose of this study was to develop a thermometry software tool for temperature monitoring during laser-induced interstitial thermotherapy (LITT). C++ programming language and several libraries including DICOM Toolkit, Grassroots DICOM library, Insight Segmentation and Registration Toolkit, Visualization Toolkit and Quasar Toolkit were used. The software’s graphical user interface creates windows displaying the temperature map and the coagulation extent in the tissue, determined by the magnetic resonance imaging (MRI) thermometry with the echo planar imaging sequence and a numerical simulation based on the radiation and heat transfer in biological tissues, respectively. The software was evaluated applying the MRI-guided LITT to ex vivo pig liver and simultaneously measuring the temperature through a fiber-optic thermometer as reference. Using the software, the temperature distribution determined by the MRI method was compared with the coagulation extent simulation. An agreement was shown between the MRI temperature map and the simulated coagulation extent. Furthermore, the MRI-based and simulated temperatures agreed with the measured one – a correlation coefficient of 0.9993 and 0.9996 was obtained, respectively. The precision of the MRI temperature amounted to 2.4°C. In conclusion, the software tool developed in the present study can be applied for monitoring and controlling the LITT procedure in ex vivo tissues.

scholarly journals Designing a compact MRI motion phantom

2016 ◽  
Vol 2 (1) ◽  
pp. 471-474
Author(s):  
Max Schmiedel ◽  
Anita Moeller ◽  
Martin A. Koch ◽  
Alfred Mertins
Keyword(s):  
Motion Compensation ◽  
Rigid Motion ◽  
Small Animal ◽  
Ground Truth ◽  
Motion Artifacts ◽  
Body Motion ◽  
Retrospective Gating ◽  
Motion Phantom ◽  
Magnetic Resonance Imaging Mri ◽  
Small Animal Mri

AbstractEven today, dealing with motion artifacts in magnetic resonance imaging (MRI) is a challenging task. Image corruption due to spontaneous body motion complicates diagnosis. In this work, an MRI phantom for rigid motion is presented. It is used to generate motion-corrupted data, which can serve for evaluation of blind motion compensation algorithms. In contrast to commercially available MRI motion phantoms, the presented setup works on small animal MRI systems. Furthermore, retrospective gating is performed on the data, which can be used as a reference for novel motion compensation approaches. The motion of the signal source can be reconstructed using motor trigger signals and be utilized as the ground truth for motion estimation. The proposed setup results in motion corrected images. Moreover, the importance of preprocessing the MRI raw data, e.g. phase-drift correction, is demonstrated. The gained knowledge can be used to design an MRI phantom for elastic motion.

scholarly journals Three dimensional echo-planar imaging at 7 Tesla

NeuroImage ◽  
2010 ◽  
Vol 51 (1) ◽  
pp. 261-266 ◽  
Author(s):  
B.A. Poser ◽  
P.J. Koopmans ◽  
T. Witzel ◽  
L.L. Wald ◽  
M. Barth
Keyword(s):  
Three Dimensional ◽  
Echo Planar Imaging ◽  
7 Tesla ◽  
Planar Imaging ◽  
Echo Planar

scholarly journals Mapping of Absolute Host Concentration and Exchange Kinetics of Xenon Hyper-CEST MRI Agents

2021 ◽  
Vol 14 (2) ◽  
pp. 79 ◽  
Author(s):  
Martin Kunth ◽  
Christopher Witte ◽  
Leif Schröder
Keyword(s):  
Spin Exchange ◽  
Chemical Exchange ◽  
Chemical Exchange Saturation Transfer ◽  
Planar Imaging ◽  
Internal Reference ◽  
Cest Mri ◽  
Exchange Kinetics ◽  
Magnetic Resonance Imaging Mri ◽  
Echo Planar

Xenon magnetic resonance imaging (MRI) provides excellent sensitivity through the combination of spin hyperpolarization and chemical exchange saturation transfer (CEST). To this end, molecular hosts such as cryptophane-A or cucurbit[n]urils provide unique opportunities to design switchable MRI reporters. The concentration determination of such xenon binding sites in samples of unknown dilution remains, however, challenging. Contrary to 1H CEST agents, an internal reference of a certain host (in this case, cryptophane-A) at micromolar concentration is already sufficient to resolve the entire exchange kinetics information, including an unknown host concentration and the xenon spin exchange rate. Fast echo planar imaging (EPI)-based Hyper-CEST MRI in combination with Bloch–McConnell analysis thus allows quantitative insights to compare the performance of different emerging ultra-sensitive MRI reporters.

scholarly journals Sir Peter Mansfield. 9 October 1933—8 February 2017

2021 ◽  
Vol 70 ◽  
pp. 313-334
Author(s):  
P. G. Morris
Keyword(s):  
Magnetic Resonance ◽  
High Speed ◽  
Imaging Technique ◽  
Functional Brain Imaging ◽  
Planar Imaging ◽  
X Ray ◽  
X Ray Crystallography ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri ◽  
Echo Planar

Peter Mansfield's rise from humble origins to founding father of magnetic resonance imaging (MRI) is an inspirational and remarkable story. His first scientific contributions were in the field of solid state nuclear magnetic resonance (NMR), and it was whilst trying to develop an NMR version of X-ray crystallography that he developed the underpinning methodology for MRI. At that time (the early 1970s) NMR was an analytical tool, ubiquitous in chemistry departments. For most of those working in the field, there was no hint that it could be developed into a diagnostic imaging technique that would reveal internal anatomy in unprecedented detail. Yet that was what happened in the space of just a few years. The first MRI scans were slow, and Peter was driven to speed them up, making physiological and later functional brain imaging studies possible. The technical challenges were many, and eschewed by healthcare equipment providers, but Peter persisted and his brainchild, echo-planar imaging, came to dominate the high speed MRI field. Peter was a gifted physicist and archetypal inventor who devoted his life to the development of a technique that has saved millions of lives. In 2003, he shared the Nobel Prize for Physiology or Medicine, in recognition of his achievement.

scholarly journals Dynamic multi-coil technique (DYNAMITE) shimming for echo-planar imaging of the human brain at 7 Tesla

NeuroImage ◽  
2015 ◽  
Vol 105 ◽  
pp. 462-472 ◽  
Author(s):  
Christoph Juchem ◽  
S. Umesh Rudrapatna ◽  
Terence W. Nixon ◽  
Robin A. de Graaf
Keyword(s):  
Human Brain ◽  
Echo Planar Imaging ◽  
7 Tesla ◽  
Planar Imaging ◽  
Echo Planar

scholarly journals Utility of Non-EPI DWI MRI in the Management of Pediatric Cholesteatoma

2019 ◽  
Vol 02 (01) ◽  
pp. 43-45
Author(s):  
Sreenivasa Murthy T.M ◽  
Anita Nagadi ◽  
Sneha Krishna Mohan
Keyword(s):  
Canal Wall ◽  
Planar Imaging ◽  
High Resolution Computed Tomography ◽  
Second Look ◽  
History Of ◽  
Magnetic Resonance Imaging Mri ◽  
The Right ◽  
Echo Planar ◽  
Intact Canal Wall Mastoidectomy ◽  
Pediatric Cholesteatoma

Abstract Introduction Cholesteatoma in children can be acquired or congenital and is generally extensive. The most commonly used technique for the removal of cholesteatoma is intact canal wall mastoidectomy. This invariably leads to second-look surgery to assess for recurrence or residual cholesteatoma. Magnetic resonance imaging (MRI) with non–echo-planar imaging (non-EPI) diffusion-weighted imaging (DWI) is an accurate noninvasive imaging option that can be used in diagnosing primary cholesteatoma. This can also be used to diagnose residual or recurrent cholesteatoma in patients who have undergone intact canal wall mastoidectomy. Case Report A 7-year-old male patient presented with a 1-week history of foul-smelling discharge from the right ear. On examination, a polypoidal mass with keratinized debris was seen. A diagnosis of cholesteatoma of right ear was made. Imaging with high-resolution computed tomography (HRCT) of the temporal bone and non-EPI DWI MRI confirmed the same. The child underwent an intact canal wall mastoidectomy and was followed up at 2 years with non-EPI DWI MRI to monitor any residual or recurrent cholesteatoma. Conclusion Non-EPI DWI MRI provides a convenient, accurate, and noninvasive method of evaluating and monitoring for residual or recurrent cholesteatoma and thus helps avoid unnecessary second-look surgery.

scholarly journals Anatomy-guided Inverse-phase-encoding Registration Method for Correcting Susceptibility Artifacts in Sub-millimeter fMRI

2019 ◽  
Author(s):  
Soan T. M. Duong ◽  
Son L. Phung ◽  
Abdesselam Bouzerdoum ◽  
Harriet G. Boyd Taylor ◽  
Alexander M. Puckett ◽  
...  
Keyword(s):  
Brain Function ◽  
Ground Truth ◽  
Planar Imaging ◽  
Phase Encoding ◽  
Susceptibility Artifacts ◽  
Registration Method ◽  
Structural Image ◽  
Magnetic Resonance Imaging Mri ◽  
Registration Scheme ◽  
Echo Planar

AbstractEcho planar imaging (EPI) is a fast and non-invasive magnetic resonance imaging (MRI) technique that supports data acquisition at spatial and temporal resolutions suitable for brain function studies. However, susceptibility artifacts are unavoidable distortions in EPI. These distortions are especially strong in high spatial resolution images and can lead to misrepresentation of brain function in fMRI experiments. A common method for correcting susceptibility artifacts is based on a registration scheme which uses two EPI images acquired using identical sequences but with inverse phase-encoding (PE) directions. In this paper, we present a new method for correcting susceptibility artifacts by integrating a T1-weighted (T1w) image into the inverse-PE based registration, since the T1w structural image is considered as a ground-truth measurement of the brain. Furthermore, the T1w image is used as a criterion to select automatically the regularization parameters of the proposed image registration. Evaluations on two high-resolution EPI-fMRI datasets, acquired at 3T and 7T scanners, confirm that the proposed method provides more robust and sharper corrections and runs faster compared with two other state-of-the-art inverse-PE based susceptibility artifact correction methods, i.e. HySCO and TOPUP.

Surgical Trauma Leads to a Shorter Survival in a Murine Orthotopic Pancreatic Cancer Model

2014 ◽  
Vol 54 (1-2) ◽  
pp. 87-94 ◽  
Author(s):  
Pia Menges ◽  
Christian Klöcker ◽  
Stephan Diedrich ◽  
Matthias Sendler ◽  
Stefan Maier ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Survival Rate ◽  
Small Animal ◽  
Immune Dysfunction ◽  
Tumour Volume ◽  
7 Tesla ◽  
Control Group ◽  
Surgical Trauma ◽  
Tumour Implantation ◽  
Small Animal Mri

Background: Abdominal surgery is frequently followed by immune dysfunction usually lasting for several days. This is especially important in cases with tumour diseases as an intact immune function is essential in this situation. Therefore, we analysed the outcome of tumour-bearing mice in a mouse model of surgically induced immune dysfunction (SID). Methods: In male C57BL/6 mice, a pancreatic tumour was implanted orthotopically. Following tumour implantation, the model of SID was applied. The control groups were either laparotomised or underwent no surgical procedure. The survival rate was determined by observation for >60 days. The tumour growth progress was imaged by a 7-tesla small animal MRI. Results: On day 60 after tumour implantation, the survival rate in SID mice was reduced to 41%. In the laparotomised group, 81% of mice survived, while the control group had a survival rate of 75%. These differences were significant (SID vs. control: p < 0.02, and SID vs. laparotomy: p < 0.002). The tumour volume was not influenced by the degree of surgical trauma. Conclusion: In pancreatic cancer, the SID model is ideally suited to investigate the influence of SID on this tumour entity.

Sign in / Sign up

Export Citation Format

Share Document