THE INFLUENCE OF TEMPERATURE AND AGE ON THE T1 RELAXATION TIME OF THE EQUINE DISTAL LIMB

Authors


  • Presented at the 15th conference of the IVRA 2009 in Bùzios, Brazil with the title “MRI T1 mapping of the equine distal limb for optimized fat suppression imaging - Research on a Low-field Standing MRI System”, where the presentation received the Oral Presentation Award

Address correspondence and reprint requests to Dr. Anna M. Adrian, 217 Linda Lane, Fort Collins, CO 80525. E-mail: anna.m.adrian@gmail.comAddress for Dr. Jennifer Kinns is Rochrann, Torview, Kippen, Stirling, Scotland FK8 3HT.

Abstract

The extent of fat suppression using short tau inversion recovery (STIR) imaging is variable between horses. Our aim was to determine if patient's age and/or hoof temperature have an influence on the T1 relaxation time of bone marrow in the equine distal limb, thereby affecting the suppression of fat signal. Magnetic resonance imaging was conducted on standing horses and cadaver samples using a low-field magnet (0.27 T). The hoof temperature was measured at the lateral side of the coronary band. A modified inversion recovery fast spin-echo (IR-FSE) sequence was used to measure the signal intensity for a range of inversion times (TIs) at six different regions of interest (ROI): (1) distal aspect of the proximal phalanx, (2) proximal aspect of the middle phalanx, (3) distal aspect of the middle phalanx, (4) navicular bone, (5) proximal aspect of the distal phalanx, and (6) distal aspect of the distal phalanx. The T1 of the bone marrow in the equine distal limb was calculated from the results and was found to increase by 3.13 ± 0.08 (SE) ms/°C. There was no significant effect of age (2–16 years) but the T1 values measured from the limbs of young (< 1 year) animals were considerably longer (32.6 ± 1.7 (SE) ms). Similar effects of temperature and age were found for all measured ROIs but there were significant differences in the mean values of T1, ranging from +7.7 (distal aspect of the distal phalanx) to −13.2 ms (distal aspect of the proximal phalanx).

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