THE APPEARANCE OF THE EQUINE METACARPOPHALANGEAL REGION ON HIGH-FIELD VS. STANDING LOW-FIELD MAGNETIC RESONANCE IMAGING

2010 ◽  
pp. no-no ◽  
Author(s):  
MEREDITH A. SMITH ◽  
SUE J. DYSON ◽  
RACHEL C. MURRAY
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Field ◽  
Resonance Imaging ◽  
Low Field

Evaluation of Magnetic Resonance Imaging Responsiveness in Active Psoriatic Arthritis at Multiple Timepoints during the First 12 Weeks of Antitumor Necrosis Factor Therapy

2015 ◽  
Vol 43 (1) ◽  
pp. 75-80 ◽  
Author(s):  
Marie Feletar ◽  
Stephen Hall ◽  
Paul Bird
Keyword(s):  
Magnetic Resonance Imaging ◽  
Psoriatic Arthritis ◽  
Magnetic Resonance ◽  
High Field ◽  
Early Response ◽  
Resonance Imaging ◽  
Low Field ◽  
Low Field Mri ◽  
Magnetic Resonance Imaging Mri ◽  
Necrosis Factor

Objective.To assess the responsiveness of high- and low-field extremity magnetic resonance imaging (MRI) variables at multiple timepoints in the first 12 weeks post-antitumor necrosis factor (anti-TNF) therapy initiation in patients with psoriatic arthritis (PsA) and active dactylitis.Methods.Twelve patients with active PsA and clinical evidence of dactylitis involving at least 1 digit were recruited. Patients underwent sequential high-field conventional (1.5 Tesla) and extremity low-field MRI (0.2 Tesla) of the affected hand or foot, pre- and postgadolinium at baseline (pre-TNF), 2 weeks (post-TNF), 6 weeks, and 12 weeks. A blinded observer scored all images on 2 occasions using the PsA MRI scoring system.Results.Eleven patients completed the study, but only 6 patients completed all high-field and low-field MRI assessments. MRI scores demonstrated rapid response to TNF inhibition with score reduction in tenosynovitis, synovitis, and osteitis at 2 weeks. Intraobserver reliability was good to excellent for all variables. High-field MRI demonstrated greater sensitivity to tenosynovitis, synovitis, and osteitis and greater responsiveness to change posttreatment. Treatment responses were maintained to 12 weeks.Conclusion.This study demonstrates the use of MRI in detecting early response to biologic therapy. MRI variables of tenosynovitis, synovitis, and osteitis demonstrated responsiveness posttherapy with high-field scores more responsive to change than low-field scores.

scholarly journals Comparison of High-field and Low-field Magnetic Resonance Imaging of Stifle Joint Disorders in Dogs

2016 ◽  
Vol 19 (3) ◽  
pp. 663-670 ◽  
Author(s):  
A. Przeworski ◽  
Z. Adamiak ◽  
J. Głodek
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Field ◽  
Cruciate Ligament ◽  
Resonance Imaging ◽  
Cranial Cruciate Ligament ◽  
Stifle Joint ◽  
Low Field ◽  
Secondary Damage ◽  
Magnetic Strength

AbstractThe most common cause of hindlimb lameness in dogs is cranial cruciate ligament rupture. In 48-77.3% of the population this trauma leads to secondary damage of the meniscus. Depending on the magnetic strength of the used device, different diagnostic accuracy can be achieved. The examination sensitivity of magnetic resonance imaging is affected by many factors which are independent of diagnostic strength, such as correct positioning of the patient, size of the stifle joint examined, or selection of the right protocol of sequences. Sensitivity of meniscus damage detection was 100% and 90%, respectively, in high- and low-field magnetic resonance. The best results were reported during examination of the stifle in dogs above 10 kg b.w. at a flexion angle of 145°, and in sagittal and dorsal planes. Regardless of the magnetic strength applied, imaging of the whole cranial cruciate ligament is difficult. Moreover, MRI allows the detection of the first signs of osteoarthritis, which were observed 4 and 6 weeks after rupture of the cranial cruciate ligament using high and low-field MRI. This also applies to lesions in the subchondral bone or a bone marrow which occurred in association with insufficiency of the stifle joint, and were mainly localized in the epiphysis of the femur and tibia. The present article provides a comparison of different examination protocols and images of damaged stifle structures, such as menisci, ligaments and bones of the stifle joint visualized with low-field and high-field magnetic resonance. Magnetic resonance arthrography is also discussed.

Comparison of low-field (0.2 Tesla) and high-field (1.5 Tesla) magnetic resonance imaging of the knee joint

1995 ◽  
Vol 114 (5) ◽  
pp. 281-286 ◽  
Author(s):  
B. Kladny ◽  
K. Gl�ckert ◽  
B. Swoboda ◽  
W. Beyer ◽  
G. Weseloh
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Knee Joint ◽  
High Field ◽  
Resonance Imaging ◽  
Low Field

TRANSSPHENOIDAL PITUITARY MACROADENOMAS RESECTION GUIDED BY POLESTAR N20 LOW-FIELD INTRAOPERATIVE MAGNETIC RESONANCE IMAGING

Neurosurgery ◽  
2009 ◽  
Vol 65 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Jin-Song Wu ◽  
Xue-Fei Shou ◽  
Cheng-Jun Yao ◽  
Yong-Fei Wang ◽  
Dong-Xiao Zhuang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Transsphenoidal Surgery ◽  
High Field ◽  
Intraoperative Imaging ◽  
Tumor Resection ◽  
Residual Tumor ◽  
Resonance Imaging ◽  
Low Field ◽  
Pituitary Macroadenomas

ABSTRACT OBJECTIVE To evaluate the applicability of low-field intraoperative magnetic resonance imaging (iMRI) during transsphenoidal surgery of pituitary macroadenomas. METHODS Fifty-five transsphenoidal surgeries were performed for macroadenomas (modified Hardy's Grade II–IV) resections. All of the surgical processes were guided by real-time updated contrast T1-weighted coronal and sagittal images, which were acquired with 0.15 Tesla PoleStar N20 iMRI (Medtronic Navigation, Louisville, CO). The definitive benefits as well as major drawbacks of low-field iMRI in transsphenoidal surgery were assessed with respect to intraoperative imaging, tumor resection control, comparison with early postoperative high-field magnetic resonance imaging, and follow-up outcomes. RESULTS Intraoperative imaging revealed residual tumor and guided extended tumor resection in 17 of 55 cases. As a result, the percentage of gross total removal of macroadenomas increased from 58.2% to 83.6%. The accuracy of imaging evaluation of low-field iMRI was 81.8%, compared with early postoperative high-field MRI (Correlation coefficient, 0.677; P <0.001). A significantly lower accuracy was identified with low-field iMRI in 6 cases with cavernous sinus invasion (33.3%) in contrast to the 87.8% found with other sites (Fisher's exact test, P <0.001). CONCLUSION The PoleStar N20 low-field iMRI navigation system is a promising tool for safe, minimally invasive, endonasal, transsphenoidal pituitary macroadenomas resection. It enables neurosurgeons to control the extent of tumor resection, particularly for suprasellar tumors, ensuring surgical accuracy and safety, and leading to a decreased likelihood of repeat surgeries. However, this technology is still not satisfying in estimating the amount of the parasellar residual tumor invading into cavernous sinus, given the false or uncertain images generated by low-field iMRI in this region, which are difficult to discriminate between tumor remnant and blood within the venous sinus.

scholarly journals Diagnosis of cerebral ventriculomegaly in felines using 0.25 Tesla and 3 Tesla magnetic resonance imaging

2018 ◽  
Vol 63 (No. 1) ◽  
pp. 28-35 ◽  
Author(s):  
P. Przyborowska ◽  
Z. Adamiak ◽  
P. Holak ◽  
Y. Zhalniarovich ◽  
WS Maksymowicz
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Field ◽  
Ventricular Volume ◽  
Magnetic Resonance Images ◽  
Magnetic Resonance Imaging Scan ◽  
Resonance Imaging ◽  
Low Field ◽  
Body Weights ◽  
The Brain

Twenty European shorthair cats with neurological disorders, aged 1–3 years and with body weights of 2.6–4.05 kg, were studied in low-field and high-field magnetic resonance imaging systems. Aims of the study were to evaluate the dilation of lateral ventricles in the examined population of cats with the use of quantitative analysis methods and to identify any differences in the results of low- and high-field magnetic resonance imaging. The average brain height was determined to 27.3 mm, and the average volume of the brain was 10 699.7 mm<sup>3</sup>. Moderately enlarged ventricles were observed in 16 symptomatic cats. Moderate unilateral enlargement was observed in one cat. Mild ventricular asymmetry was described in four animals. The average difference in ventricular height between measurements obtained in low- and high-field magnetic resonance imaging was 0.37 ± 0.16% and for ventricular volume it was 0.62 ± 0.29%. The magnetic resonance imaging scan did not reveal statistically significant differences in brain height or volume between healthy and cats with ventriculomegaly. The differences in the results of low- and high-field magnetic resonance imaging were not statistically significant. Described findings could facilitate the interpretation of magnetic resonance images in cats with ventriculomegaly or hydrocephalus.

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