Steerable Guidewire for Magnetic Resonance Guided Endovascular Interventions

2014 ◽  
Vol 8 (2) ◽  
Author(s):  
H. C. M. Clogenson ◽  
J. Dankelman ◽  
J. J. van den Dobbelsteen
Keyword(s):  
Magnetic Resonance ◽  
Vascular System ◽  
Proof Of Concept ◽  
X Ray ◽  
Endovascular Interventions ◽  
Tissue Contrast ◽  
Current Design ◽  
Magnetic Resonance Imaging Mri ◽  
To Come ◽  
Flexible Instruments

In endovascular interventions, thin, flexible instruments are inserted through the skin into the blood vessels to diagnose and treat various diseases of the vascular system. One drawback is that the instruments are difficult to maneuver in the desired direction due to limitations in shape and flexibility. Another disadvantage is that the interventions are performed under intermittent fluoroscopy/angiography imaging. Magnetic resonance imaging (MRI) may offer advantages over X-ray guidance. It presents a good soft tissue contrast without the use of nephrotoxic media or ionizing radiation. The aim of this study is to develop a guidewire that is compatible with MRI and includes a steerable segment at the tip. This added degree-of-freedom may improve the maneuverability of the devices thereby the efficiently and safety of the navigation. A 1.6 m (5 ft, 3 in.) long and 0.035 in. diameter guidewire that consists of MR compatible materials and has a flexible tip was designed. The only metallic part was a nitinol rod that was implemented at the distal flexible tip. To limit the risk of heating in the MRI, this rod was kept shorter than 30 mm. The tip could be deflected in one direction by pulling on a Dyneema wire that was placed in the lumen of the shaft of the guidewire. To drive the steerable tip, a handle that could be easily attached/detached from the instrument was designed and implemented. Using the handle, the tip of the 1.60 m long guidewire prototype could be actuated to reach angles from 30 deg to 250 deg. The handle could easily be placed on and removed from the guidewire, so conventional 0.035 in.–compatible catheters could slide over from the proximal end. However, in order to make the guidewire more efficient to enter a bifurcation, the stiffness of the tip should progressively increase from its proximal to its distal end. The guidewire was imaged in a 1.5T MRI using real-time imaging without producing artifacts that would have shaded the anatomy. It was possible to assemble a guidewire with a steerable segment in the required size, using MR compatible materials. Therefore, the current design is a promising proof of concept and allowed us to clearly identify the features that need to be improved in order to come to a clinically applicable instrument.

scholarly journals In vivo imaging techniques: a new era for histochemical analysis

2016 ◽  
Author(s):  
A. Busato ◽  
P. Fumene Feruglio ◽  
P.P. Parnigotto ◽  
P. Marzola ◽  
A. Sbarbati
Keyword(s):  
Magnetic Resonance ◽  
In Vivo Imaging ◽  
Diffusion Tensor ◽  
Technological Development ◽  
Imaging Techniques ◽  
Resonance Spectroscopy ◽  
Preclinical Research ◽  
Tissue Contrast ◽  
Magnetic Resonance Imaging Mri

In vivo imaging techniques can be integrated with classical histochemistry to create an actual histochemistry of water. In particular, Magnetic Resonance Imaging (MRI), an imaging technique primarily used as diagnostic tool in clinical/preclinical research, has excellent anatomical resolution, unlimited penetration depth and intrinsic soft tissue contrast. Thanks to the technological development, MRI is not only capable to provide morphological information but also and more interestingly functional, biophysical and molecular. In this paper we describe the main features of several advanced imaging techniques, such as MRI microscopy, Magnetic Resonance Spectroscopy, functional MRI, Diffusion Tensor Imaging and MRI with contrast agent as a useful support to classical histochemistry.

scholarly journals Magnetic resonance imaging of salivary glands

2019 ◽  
Author(s):  
Danielle Ayumi Nishimura ◽  
Ana Luiza Esteves Carneiro ◽  
Kaisermann Costa ◽  
Wladimir Gushiken de Campos ◽  
Jefferson Xavier de Oliveira ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Salivary Glands ◽  
Imaging Techniques ◽  
Neck Region ◽  
Evaluation Instrument ◽  
Resonance Imaging ◽  
Tissue Contrast ◽  
Excellent Method ◽  
Magnetic Resonance Imaging Mri

Salivary glands tumors account for 2-5% of tumors in the head and neck region, possibly being benign or malignant. Magnetic resonance imaging (MRI) presents high soft tissue contrast resolution, thus being an excellent method for salivary gland analysis. The objective of this literature review is to analyze MRI as an evaluation instrument for the diagnosis of salivary glands lesions. Compared to other imaging techniques, MRI can better evaluate the relationship between adjacent anatomical structures, presenting greater sensitivity and specificity.

scholarly journals Implementation of a dedicated 1.5 T MR scanner for radiotherapy treatment planning featuring a novel high-channel coil setup for brain imaging in treatment position

2020 ◽  
Author(s):  
Veit Mengling ◽  
Christoph Bert ◽  
Rosalind Perrin ◽  
Siti Masitho ◽  
Thomas Weissmann ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Brain Imaging ◽  
Treatment Planning ◽  
Signal To Noise Ratio ◽  
Motion Artifacts ◽  
Radiotherapy Treatment Planning ◽  
Tissue Contrast ◽  
Flexible Coil ◽  
Magnetic Resonance Imaging Mri

Abstract Purpose To share our experiences in implementing a dedicated magnetic resonance (MR) scanner for radiotherapy (RT) treatment planning using a novel coil setup for brain imaging in treatment position as well as to present developed core protocols with sequences specifically tuned for brain and prostate RT treatment planning. Materials and methods Our novel setup consists of two large 18-channel flexible coils and a specifically designed wooden mask holder mounted on a flat tabletop overlay, which allows patients to be measured in treatment position with mask immobilization. The signal-to-noise ratio (SNR) of this setup was compared to the vendor-provided flexible coil RT setup and the standard setup for diagnostic radiology. The occurrence of motion artifacts was quantified. To develop magnetic resonance imaging (MRI) protocols, we formulated site- and disease-specific clinical objectives. Results Our novel setup showed mean SNR of 163 ± 28 anteriorly, 104 ± 23 centrally, and 78 ± 14 posteriorly compared to 84 ± 8 and 102 ± 22 anteriorly, 68 ± 6 and 95 ± 20 centrally, and 56 ± 7 and 119 ± 23 posteriorly for the vendor-provided and diagnostic setup, respectively. All differences were significant (p > 0.05). Image quality of our novel setup was judged suitable for contouring by expert-based assessment. Motion artifacts were found in 8/60 patients in the diagnostic setup, whereas none were found for patients in the RT setup. Site-specific core protocols were designed to minimize distortions while optimizing tissue contrast and 3D resolution according to indication-specific objectives. Conclusion We present a novel setup for high-quality imaging in treatment position that allows use of several immobilization systems enabling MR-only workflows, which could reduce unnecessary dose and registration inaccuracies.

Magnetic resonance imaging in gynecological practice

1997 ◽  
Vol 78 (6) ◽  
pp. 439-441
Author(s):  
A. T. Valiullina ◽  
L. M. Tukhvatullina ◽  
R. F. Bakhtiozin ◽  
I. R. Chuvashaev
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Soft Tissues ◽  
Dynamic Control ◽  
Anatomical Structure ◽  
Resonance Imaging ◽  
Noninvasive Diagnostics ◽  
Tissue Contrast ◽  
Magnetic Resonance Imaging Mri ◽  
Natural Tissue

Magnetic resonance imaging (MRI) has become one of the leading methods of noninvasive diagnostics in the last 10 years. Interest in this type of examination is due to its great potential possibilities: absence of radiation exposure, high natural tissue contrast, obtaining sections of any orientation, possibility of multiple examination and dynamic control, determining not only the anatomical structure of soft tissues, but also their chemical composition.

scholarly journals Correlation between magnetic resonance, X-ray imaging alterations and histological changes in an ovine model of age-related disc degeneration

2021 ◽  
Vol 42 ◽  
pp. 166-178
Author(s):  
N Bouhsina ◽  
◽  
C Decante ◽  
JB Hardel ◽  
S Madec ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Disc Degeneration ◽  
Disc Height ◽  
Strongly Correlated ◽  
X Ray ◽  
Age Related ◽  
Magnetic Resonance Imaging Mri ◽  
The Many ◽  
Tissue Alterations ◽  
Ivd Degeneration

Sheep are one of the many animal models used to investigate the pathophysiology of disc degeneration and the regenerative strategies for intervertebral disc (IVD) disease. To date, few studies have thoroughly explored ageing of ovine lumbar IVDs. Hence, the objective of the present study was to concomitantly assess the development of spontaneous age-related lumbar IVD degeneration in sheep using X-ray, magnetic resonance imaging (MRI) as well as histological analyses. 8 young ewes (< 48 months old) and 4 skeletally mature ewes (> 48 months old) were included. Disc height, Pfirrmann and modified Pfirrmann grades as well as T2-wsi and T2 times were assessed by X-ray and MRI. The modified Boos score was also determined using histology sections. Pfirrmann (2 to 3) and modified Pfirrmann (2 to 4) grades as well as Boos scores (7 to 13) gradually increased with ageing, while T2-weighted signal intensity (1.18 to 0.75), T2 relaxation time (114.36 to 70.65 ms) and disc height (4.1 to 3.2 mm) decreased significantly. All the imaging modalities strongly correlated with the histology (p < 0.0001). The present study described the suitability of sheep as a model of age-related IVD degeneration by correlation of histological tissue alterations with the changes observed using X-ray and MRI. Given the structural similarities with humans, the study demonstrated that sheep warrant being considered as a pertinent animal model to investigate IVD regenerative strategies without induction of degeneration.

scholarly journals A Clinical Prospective Observational Cohort Study on the Prevalence and Primary Diagnostic Accuracy of Occult Vertebral Fractures in Aged Women with Acute Lower Back Pain Using Magnetic Resonance Imaging

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Atsushi Terakado ◽  
Sumihisa Orita ◽  
Kazuhide Inage ◽  
Go Kubota ◽  
Tomohiro Kanzaki ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Back Pain ◽  
Magnetic Resonance ◽  
Diagnostic Accuracy ◽  
Elderly Women ◽  
Resonance Imaging ◽  
Mineral Density ◽  
X Ray ◽  
Acute Low Back Pain ◽  
Magnetic Resonance Imaging Mri

Background.Elderly female patients complaints of acute low back pain (LBP) may involve vertebral fracture (VF), among which occult VF (OVF: early-stage VF without any morphological change) is often missed to be detected by primary X-ray examination. The current study aimed to investigate the prevalence of VF and OVF and the diagnostic accuracy of the initial X-ray in detecting OVF.Method.Subjects were elderly women (>70 years old) complaining of acute LBP with an accurate onset date. Subjects underwent lumbar X-ray, magnetic resonance imaging (MRI), and bone mineral density (BMD) measurement at their first visit. The distribution of radiological findings from X-ray and magnetic resonance imaging (MRI) as well as the calculation of the prevalence of VF and OVF are investigated.Results. The prevalence of VF among elderly women with LBP was 76.5% and L1 was the most commonly injured level. Among VF cases, the prevalence of OVF was 33.3%. Furthermore, osteoporotic patients tend to show increased prevalence of VF (87.5%). The predictive values in detecting VF on the initial plain X-ray were as follows: sensitivity, 51.3%; specificity, 75.0%; and accuracy rate, 56.7%.Conclusions.Acute LBP patients may suffer vertebral injury with almost no morphologic change in X-ray, which can be detected using MRI.

Radiology

2014 ◽  
Author(s):  
Murray Longmore ◽  
Ian B. Wilkinson ◽  
Andrew Baldwin ◽  
Elizabeth Wallin
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Magnetic Resonance ◽  
Ionizing Radiation ◽  
Resonance Imaging ◽  
X Ray ◽  
Chest X Ray ◽  
Effective Doses ◽  
Magnetic Resonance Imaging Mri

Principles in radiology:Typical effective dosesJustifying exposure to ionizing radiationThe art of the requestInterpreting an imagePresenting an imageModalities:Chest x-ray (cxr) –740Plain abdominal x-rayComputed tomography (ct) –746Magnetic resonance imaging (mri...

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