Time-of-flight magnetic resonance angiography (TOF-MRA) of the normal equine head.
Authors: Manso-Díaz G, García-Real M I, Casteleyn C, San-Román F, Taeymans O
Journal: Equine veterinary journal
Summary
# Editorial Summary Time-of-flight MRA has become routine in human and small animal imaging but remained unexplored in equine practice until this 2013 study, which established it as a non-invasive alternative to contrast-enhanced angiography for visualising head vasculature. Researchers scanned five healthy horses using both low-field (0.23T) and high-field (1.5T) MRI systems with a 2D TOF-MRA protocol, cross-referencing their images against vascular corrosion casts for anatomical accuracy. The technique successfully depicted all major intra- and extracranial vessels down to approximately 2 mm diameter and identified arterial branches to the 3rd–4th order of ramification, though arterial signal intensity was notably superior to venous visualisation. High-field systems delivered substantially better resolution, particularly for smaller arterial branches, whilst low-field machines remained clinically adequate for diagnostic purposes. For equine practitioners, this work provides a validated imaging pathway for preoperative vascular mapping in surgical cases and enables non-invasive characterisation of head pathologies—particularly neoplasia and guttural pouch mycosis—without the cost, time, or safety concerns associated with contrast administration.
Read the full abstract on PubMed
Practical Takeaways
- •MRA offers a safe, contrast-free imaging alternative for evaluating equine head vasculature in cases requiring preoperative planning for head surgery
- •High-field MRI provides superior vascular detail; consider referral to high-field facilities when detailed small vessel anatomy is clinically critical
- •This technique can help characterize and stage head conditions like guttural pouch mycosis and neoplasia by defining vascular involvement and anatomy
Key Findings
- •TOF 2D-MRA successfully visualized all major intra- and extracranial vessels down to approximately 2 mm diameter on both low-field (0.23T) and high-field (1.5T) MRI systems
- •High-field MRA protocol provided superior visualization of small arterial branches with better resolution compared to low-field imaging
- •Arteries showed higher signal intensity than veins, allowing visualization to the 3rd-4th order of vascular ramification
- •Noncontrast MRA technique eliminates the need for contrast media while providing anatomically detailed vascular mapping suitable for preoperative planning