scholarly journals Application of Surgical Lead Management and Reconfigurable Coil Technology to Reduce RF Heating of DBS Implants during MRI at 3T Under Variant Body Compositions

2020 ◽  
Author(s):  
Bhumi Bhusal ◽  
Behzad Elahi ◽  
Boris Keil ◽  
Joshua Rosenow ◽  
Ehsan Kazemivalipour ◽  
...  
Keyword(s):  
Electric Fields ◽  
The Body ◽  
Mitigation Strategies ◽  
Rf Heating ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri ◽  
Lead Management ◽  
Body Compositions ◽  
Phantom Experiments ◽  
Deep Brain

AbstractPatients with active implants such as deep brain stimulation (DBS) devices, have limited access to magnetic resonance imaging (MRI) due to risks of RF heating. With an aging population, the prevalence of neurodegenerative and vascular disease increases; and so does the indication for MRI exams in patients with such implants. In response to this growing need for MRI, many groups have investigated strategies to mitigate the RF heating of the implants. These efforts, however, have relied either on simulations with homogenous body models or simplified phantom experiments (box shaped phantom with single tissue). It is well established, however, that the shape and heterogeneity of human body affects the distribution of MRI electric fields, which by proxy, alters the RF heating of an implant inside the body. In this contribution, we applied numerical simulations and phantom experiments to examine the effectiveness of RF heating mitigation strategies under variant patient body compositions, focusing on two recently proposed techniques: (a) surgical modification of DBS lead trajectories inside the body, and (b) use of a patient-adjustable reconfigurable MRI coil, both aiming to reduce the coupling of implanted leads and MRI electric fields. Our results demonstrated that both techniques perform well under variant body compositions.

scholarly journals Reconfigurable MRI coil technology can substantially reduce RF heating at the tips of bilateral deep brain stimulation implants

2018 ◽  
Author(s):  
Laleh Golestanirad ◽  
Boris Keil ◽  
Sean Downs ◽  
John Kirsch ◽  
Behzad Elahi ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Temperature Rise ◽  
Substantial Reduction ◽  
The Body ◽  
Rf Heating ◽  
Coil System ◽  
Body Coil ◽  
Magnetic Resonance Imaging Mri ◽  
Deep Brain

AbstractPatients with deep brain stimulation (DBS) implants can significantly benefit from magnetic resonance imaging (MRI) examination, however, access to MRI is restricted in this patients because of safety concerns due to RF heating of the leads. Recently we introduced a patient-adjustable reconfigurable MRI coil system to reduce the SAR at the tip of deep brain stimulation implants during MRI at 1.5T. A simulation study with realistic models of single (unilateral) DBS leads demonstrated a substantial reduction in the local SAR up to 500-fold could be achieved using the coil system compared to quadrature birdcage coils. Many patients however, have bilateral DBS implants and the question arises whether the rotating coil system can be used in for them. This work reports the results of phantom experiments measuring the temperature rise at the tips of bilateral DBS implants with realistic trajectories extracted from postoperative CT images of 10 patients (20 leads in total). A total of 200 measurements were performed to record temperature rise at the tips of the leads during 2 minutes of scanning with the coil rotated to cover all accessible rotation angles. In all patients, we were able to find an optimum coil rotation angle and reduced the heating of both left and right leads to a level below the heating produced by the body coil. An average heat reduction of 65% was achieved for bilateral leads. Reconfigurable coil technology introduces a promising approach for imaging of patients with DBS implants.

Magnetic Resonance Imaging in the Diagnosis of Disruption of the Posterior Tibial Tendon

Foot & Ankle ◽  
1987 ◽  
Vol 8 (3) ◽  
pp. 144-147 ◽  
Author(s):  
Ian J. Alexander ◽  
Kenneth A. Johnson ◽  
Thomas H. Berquist
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Soft Tissues ◽  
Diagnostic Technique ◽  
Clinical Findings ◽  
The Body ◽  
Posterior Tibial Tendon ◽  
Resonance Imaging ◽  
Posterior Tibial ◽  
Magnetic Resonance Imaging Mri

Magnetic resonance imaging (MRI), a useful technique of studying soft tissues of the body, can be very effective in assessing the integrity of tendons. Usually a patient with a complete tear of the posterior tibial tendon has characteristic physical findings. In the patient presented, MRI demonstrated a complete disruption of the posterior tibial tendon, despite the absence of the commonly associated clinical findings. In view of the difficulties encountered with attempted tenography of the completely torn posterior tibial tendon, MRI provides a sensitive alternative diagnostic technique.

scholarly journals Incidental Findings in Magnetic Resonance Imaging (MRI) Brain Research

2008 ◽  
Vol 36 (2) ◽  
pp. 315-319 ◽  
Author(s):  
Charles A. Nelson
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Incidental Findings ◽  
Brain Research ◽  
The Body ◽  
7 Tesla ◽  
X Rays ◽  
Resonance Imaging ◽  
Imaging Tool ◽  
Magnetic Resonance Imaging Mri

Magnetic resonance imaging (MRI) is a noninvasive imaging tool that utilizes a strong magnetic field and radio frequency waves to visualize in great detail organs, soft tissue, and bone. Unlike conventional x-rays (including computed tomography [CT]), there is no exposure to ionizing radiation and at most field strengths (generally below 7 Tesla) the procedure is considered safe for nearly every age group. Because it is non-invasive (i.e., does not break the skin or harm the body) and possesses excellent spatial resolution (down to millimeters), the use of MRI as a research tool has increased exponentially over the past decade. Uses have ranged from add-ons to a clinical study (e.g., after scanning a child who has fallen from a bicycle, the radiologist might do an extra sequence to explore ways of obtaining higher resolution images) to studies of brain development in typically developing children. In addition, a major effort has been made in recent years to use MRI to study brain function (so-called “functional MRI” [fMRI]). Because the clinical utility of fMRI has not yet been realized, fMRI is still considered highly exploratory, and we cannot yet identify incidental findings of a functional (as opposed to structural) nature.

Boron-gadolinium binary system as a magnetic resonance imaging boron carrier

2003 ◽  
Vol 75 (9) ◽  
pp. 1343-1348 ◽  
Author(s):  
Yoshinori Yamamoto
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Binary System ◽  
The Body ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri

The evaluation of the Gd-carborane DTPA complex as a magnetic resonance imaging (MRI) and boron carrier agent was carried out in vivo. The MRI revealed that the Gd-carborane DTPA was metabolized slower in the body in comparison with Gd-DTPA.

scholarly journals The Use of Magnetic Resonance Imaging-guided Focused Ultrasound in Movement Disorders—A Review

US Neurology ◽  
2017 ◽  
Vol 13 (02) ◽  
pp. 74
Author(s):  
Lauren S Talman ◽  
Binit B Shah ◽  
◽  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Movement Disorders ◽  
Focused Ultrasound ◽  
Full Potential ◽  
Resonance Imaging ◽  
Strong Focus ◽  
Magnetic Resonance Imaging Mri ◽  
Surgical Treatments ◽  
Deep Brain

The use of surgical treatments for movement disorders has been well established for several decades, with a strong focus, in the past, on ablative lesioning procedures and, more recently, deep brain stimulation. Magnetic resonance imaging (MRI)-guided focused ultrasound (MRgFUS) is emerging as a newly recognized surgical technique for the treatment of various movement disorders. The most robust data, demonstrating safety and efficacy of MRgFUS, have been published in trials directed at treatment of essential tremor (ET); however, many trials are underway to define its role in other movement disorders, such as Parkinson’s disease with preliminary results echoing those from studies in ET. The full potential for use of MRgFUS, both in the field of movement disorders and beyond, is only beginning to be explored.

How is magnetic resonance imaging used in Iran?

2008 ◽  
Vol 24 (04) ◽  
pp. 452-458 ◽  
Author(s):  
Mohammad Palesh ◽  
Sten Fredrikson ◽  
Hamidreza Jamshidi ◽  
Goran Tomson ◽  
Max Petzold
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Low Income ◽  
Spinal Column ◽  
The Body ◽  
Low Income Countries ◽  
Resonance Imaging ◽  
Utilization Patterns ◽  
Magnetic Resonance Imaging Mri ◽  
Almost All

Objectives:Analysis of and understanding the utilization patterns of diagnostic imaging technologies is important for planning health systems especially in middle- and low-income countries. Almost all published studies have been focused on utilization trends or utilization rates of magnetic resonance imaging (MRI) over time and little has been published about utilization patterns of MRI. This study aims to identify and describe the utilization pattern of MRI in Iran.Methods:Data was collected from referrals and MRI reports of the population covered by one of the largest insurance organizations (Social Security Organization [SSO]) with more than 27 million beneficiaries in the Country. We focused on patients who had undergone an MRI examination during 1 month (October 13 to November 12), 2005. The data collected consisted of 1,656 referrals for MR imaging and 1,547 MRI reports.Results:No clear association was found between the number of referrals per 100,000 population and the number of MRI machines per 100,000 population (r = 0.30;p= .13). Neurosurgeons, orthopedists, and neurologists contributed to more than 88 percent of MRI utilization. The Spinal column (55 percent), brain (25.5 percent), and knee (11.0 percent) were the most common parts of the body scanned by MRI.Conclusions:Having identified some of the most frequent users of MRI technology, any plan for modifying or improving MRI use should focus mainly on these specialties. International evidence on using the technology for examining brain and spine indicate that MRI is mainly used in diagnosing the central nervous system (CNS) diseases.

Utilizing magnetic resonance imaging (MRI) to assess the effects of angling-induced barotrauma on rockfish (Sebastes)

2008 ◽  
Vol 65 (7) ◽  
pp. 1245-1249 ◽  
Author(s):  
Bonnie L. Rogers ◽  
Christopher G. Lowe ◽  
Esteban Fernández-Juricic ◽  
Lawrence R. Frank
Keyword(s):  
Magnetic Resonance Imaging ◽  
Image Segmentation ◽  
Magnetic Resonance ◽  
Three Dimensional ◽  
The Body ◽  
The Other ◽  
Bladder Rupture ◽  
Swim Bladder ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri

The physical consequences of barotrauma on the economically important rockfish ( Sebastes ) were evaluated with a novel method using T2-weighted magnetic resonance imaging (MRI) in combination with image segmentation and analysis. For this pilot study, two fishes were captured on hook-and-line from 100 m, euthanized, and scanned in a 3 Tesla human MRI scanner. Analyses were made on each fish, one exhibiting swim bladder overinflation and exophthalmia and the other showing low to moderate swim bladder overinflation. Air space volumes in the body were quantified using image segmentation techniques that allow definition of individual anatomical regions in the three-dimensional MRIs. The individual exhibiting the most severe signs of barotrauma revealed the first observation of a gas-filled orbital space behind the eyes, which was not observable by gross dissection. Severe exophthalmia resulted in extreme stretching of the optic nerves, which was clearly validated with dissections and not seen in the other individual. Expanding gas from swim bladder overinflation must leak from the swim bladder, rupture the peritoneum, and enter the cranium. This MRI method of evaluating rockfish following rapid decompression is useful for quantifying the magnitude of internal barotrauma associated with decompression and complementing studies on the effects of capture and discard mortality of rockfishes.

scholarly journals Virtopsy—The Scalpel Free Autopsy: A Review of Literature

2015 ◽  
Vol 5 (3) ◽  
pp. 168-172
Author(s):  
Amita Rahul Navalkar
Keyword(s):  
Three Dimensional ◽  
The Body ◽  
Review Of Literature ◽  
Resonance Imaging ◽  
Forensic Imaging ◽  
Virtual Autopsy ◽  
One Step ◽  
Magnetic Resonance Imaging Mri ◽  
3D Scans ◽  
To Receive

ABSTRACT Forensic medicine aims for the documentation of medical and other forensic findings in living and deceased persons for the police and the judiciary system. Autopsy is the scientific examination of bodies after death, where whole surface of the body as well as all the body cavities are explored to record the findings. At the same time it is also equally important to consider the sentiments of the relatives of the deceased who may get upset at conventional autopsies. So, if there exists a means by which all the findings in the body can be established without hurting anyone's sentiments should be accepted. Virtopsy or virtual autopsy is one step ahead in this field where three-dimensional (3D) scans using computed tomography (CT) scans and magnetic resonance imaging (MRI) pictures are employed sans using the scalpel for performing autopsies on victims to receive more information aiding in diagnosis and contributing significantly toward forensic science. This review wishes to highlight virtopsy as an important tool in forensic imaging and identification. How to cite this article Navalkar AR. Virtopsy—The Scalpel Free Autopsy: A Review of Literature. J Contemp Dent 2015;5(3):168-172.

scholarly journals A Case Report of Primary Brain Hydatid Cyst in a Child

2020 ◽  
Vol 6 (1) ◽  
pp. 41-48
Author(s):  
Deepak Garg ◽  
◽  
Gaurav Jain ◽  
Virendra Sinha ◽  
◽  
...  
Keyword(s):  
Hydatid Cyst ◽  
Female Child ◽  
The Body ◽  
Body Parts ◽  
Resonance Imaging ◽  
Limb Weakness ◽  
Case Presentation ◽  
Clinical Presentations ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain

Background and Importance: Hydatid cyst is endemic in India, with different clinical presentations according to the site of involvement in the body. However, its occurrence in the brain without the involvement of other body parts is rare. Case Presentation: An eight-year-old female child presented with right-sided limb weakness and slurring of speech. The diagnosis of primary brain hydatid cyst was made with Magnetic Resonance Imaging (MRI) of the brain. The cyst was removed completely, resulting in improved post-operative slurring of speech and limb weakness. Conclusion: In countries where hydatid disease is endemic, brain hydatidosis should on top of the differential diagnoses for intracerebral cystic lesions and managed as per hydatid protocol until proved otherwise. This approach is critical to prevent rupture and dissemination.

Sign in / Sign up

Export Citation Format

Share Document