Asymmetric signal intensity in normal collateral ligaments of the distal interphalangeal joint in horses with a low-field MRI system due to the magic angle effect.
Abstract: Increased signal intensity in one of the collateral ligaments of the distal interphalangeal (DIP) joint of sound horses in images acquired using a low-field magnet with vertical orientation of the magnetic field was investigated as a possible manifestation of the magic angle effect. Three isolated equine digits were imaged using the following pulse sequences: (1) spin echo TI, (2) turbo spin echo proton density and T2, and (3) 3D gradient echo T1, in different positions by mildly changing the orientation of the long axis of the digit, in the dorsal plane, relative to the magnetic field. The signal intensity in a ligament was significantly increased when the ligament orientation relative to the magnetic field was 55 +/- 10 degrees. The signal intensity was markedly increased in pulse sequences with short echo time (TE) 5.0, 4.9, and 3.9 times increased, respectively, for 3D gradient echo T1, spin echo T1, and turbo spin echo proton density) and to a lesser extent with pulse sequences with a longer TE (1.8 times increased for turbo spin echo T2). These changes are characteristic of the magic angle effect. Because of the anatomic orientation of the collateral ligaments of the DIP joint, a slight deviation of the long axis of the digit in the dorsal plane, from the ideal horizontal position, will induce an increased signal intensity that can be confused with desmitis. Careful positioning of the foot in magnetic resonance imaging systems where B0 is perpendicular to the long axis of the digit is critical to prevent the occurrence of the magic angle effect.
Publication Date: 2007-03-28 PubMed ID: 17385363DOI: 10.1111/j.1740-8261.2007.00211.xGoogle Scholar: Lookup
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- Journal Article
- Anatomy
- Biomechanics
- Clinical Findings
- Clinical Pathology
- Clinical Study
- Diagnosis
- Diagnostic Imaging
- Diagnostic Technique
- Disease Diagnosis
- Distal Interphalangeal Joint
- Equine Diseases
- Equine Health
- Horses
- Imaging Techniques
- Ligaments
- Magnetic Resonance Imaging
- Musculoskeletal System
- Physiology
- Veterinary Medicine
- Veterinary Procedure
- Veterinary Research
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research analyzes the unexpected increase in signal intensity observed in one of the collateral ligaments of horse’s distal interphalangeal (DIP) joint during low-field magnetic resonance imaging (MRI) which might be due to the influence of the magic angle effect.
Study Procedure
- The study was performed to investigate an unusual observation during the use of a low-field MRI system on horses’ DIP joint. The researchers observed an increased signal intensity in one of the collateral ligaments in healthy horses, which they suspected was a manifestation of the magic angle effect.
- Three isolated horse digits were used in the study. These were imaged using three types of pulse sequences: spin echo TI, turbo spin echo proton density and T2, and 3D gradient echo T1. The digits were positioned differently, by slightly altering the direction of the long axis of the digit in relation to the magnetic field.
Findings
- Findings from the experiment showed a substantial increase in the ligament’s signal intensity when the orientation relative to the magnetic field was 55 +/- 10 degrees. This increase in signal intensity was particularly notable in pulse sequences with short echo time (TE) such as 3D gradient echo T1, spin echo TI, and turbo spin echo proton density.
- The signal intensity was only moderately increased in pulse sequences with longer echo times. These changes in signal intensity with varying echo times are characteristic of the magic angle effect.
- However, due to the anatomic positioning of the DIP joint’s collateral ligaments, a small deviation from the normal horizontal position could lead to increased signal intensity that could be mistaken for desmitis — inflammation of a ligament.
Conclusion
- The researchers conclude that it is crucial to carefully position the foot in MRI systems. This is in order to prevent the occurrence of the magic angle effect, particularly in systems where B0 is perpendicular to the long axis of the digit.
- The study emphasizes the importance of understanding how different positioning and imaging techniques can affect the results of MRI scans in veterinary science, especially when diagnosing potential ligament diseases in equines.
Cite This Article
APA
Spriet M, Mai W, McKnight A.
(2007).
Asymmetric signal intensity in normal collateral ligaments of the distal interphalangeal joint in horses with a low-field MRI system due to the magic angle effect.
Vet Radiol Ultrasound, 48(2), 95-100.
https://doi.org/10.1111/j.1740-8261.2007.00211.x Publication
Researcher Affiliations
- Section of Sports Medicine and Imaging, New Bolton Center, University of Pennsylvania, 382 West Street Road, Kennett Square, PA 19348, USA. spriet@vet.upenn.edu
MeSH Terms
- Animals
- Horses
- Magnetic Resonance Imaging / methods
- Magnetic Resonance Imaging / veterinary
- Toe Joint / anatomy & histology
Citations
This article has been cited 3 times.- Przeworski A, Adamiak Z, Nowicki M, Mieszkowska M, Tobolska A, Głodek J. Assessment of the Usefulness of Image Reconstruction in the Oblique and Double-oblique Sagittal Planes for Magnetic Resonance Imaging of the Canine Cranial Cruciate Ligament. J Vet Res 2021 Jun;65(2):209-216.
- Hedenström UO, Wattle OS. Significance of ossificated ungular cartilages regarding the performance of cold-blooded trotters. Acta Vet Scand 2014 Oct 25;56(1):74.
- De Moura HL, Monga A, Zhang X, Zibetti MVW, Keerthivasan MB, Regatte RR. Feasibility of 3D MRI fingerprinting for rapid knee cartilage T(1), T(2,) and T(1ρ) mapping at 0.55T: Comparison with 3T. NMR Biomed 2024 Dec;37(12):e5250.
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