Murray Rachel C, Dyson Sue J, Schramme Michael C, Branch Marion, Woods Sarah
Animal Health Trust, Lanwades Park, Kentford, Newmarket, CB8 7UU, UK.
Vet Radiol Ultrasound. 2003 Nov-Dec;44(6):609-17. doi: 10.1111/j.1740-8261.2003.tb00519.x.
Chronic laminitis is a severe disease affecting the equine digit. It was hypothesized that magnetic resonance (MR) imaging would improve visualization of structures within the foot and pathology associated with chronic laminitis. This study aimed to describe the MR imaging findings in chronic laminitis, compare different pulse sequences for visualization of pathology, and to compare MR imaging with standard radiography. Twenty (10 forelimb, 10 hindlimb) cadaver limbs from 10 horses clinically diagnosed with chronic laminitis (group L) and 10 limbs without laminitis (group N) were used. Lateromedial radiographs and sagittal and transverse MR images of the foot were obtained. Radiographs and MR images were evaluated for anatomic definition and evidence of pathology. Dorsal hoof wall thickness and angle of rotation and displacement distance of the distal phalanx were measured. Comparisons were made between group L and N, forelimb and hindlimb within each horse, and MR imaging and radiography. Features consistently noted with MR images in group L, but not detected using radiography, included laminar disruption, circumscribed areas of laminar gas, laminar fluid, and bone medullary fluid. Other findings seen only on MR images included increased size and number of vascular channels, alterations in the corium coronae, and distal interphalangeal joint distension. Magnetic resonance imaging allowed better definition of laminar gas lines and P3 surface irregularity observed on radiographs. Based on measurements, group L had a greater angle of rotation, distal displacement, and dorsal hoof wall thickness than group N; forelimb hoof wall thickness was greater than hindlimb; and distal displacement and hoof wall thickness measurements were smaller using MR imaging than radiography, but had a similar pattern. It is concluded that there are features of chronic laminitis consistently observed using MR imaging and that these may be additional to features observed radiographically.
慢性蹄叶炎是一种影响马属动物蹄部的严重疾病。据推测，磁共振（MR）成像将改善蹄部结构及与慢性蹄叶炎相关病理变化的可视化。本研究旨在描述慢性蹄叶炎的MR成像表现，比较不同脉冲序列对病理变化的可视化效果，并将MR成像与标准X线摄影进行比较。使用了来自10匹临床诊断为慢性蹄叶炎的马（L组）的20个（10个前肢、10个后肢）尸体肢以及10个无蹄叶炎的肢体（N组）。获取了蹄部的内外侧X线片以及矢状面和横断面MR图像。对X线片和MR图像进行了解剖结构清晰度及病理变化证据的评估。测量了背侧蹄壁厚度、远节指骨的旋转角度和移位距离。对L组和N组、每匹马的前肢和后肢以及MR成像和X线摄影之间进行了比较。L组中在MR图像上始终可见但X线摄影未检测到的特征包括蹄叶破坏、局限性蹄叶气体区域、蹄叶积液和骨髓液。仅在MR图像上发现的其他表现包括血管通道大小和数量增加、冠状真皮改变以及远侧指间关节扩张。磁共振成像能更好地显示X线片上观察到的蹄叶气体线和P3表面不规则情况。基于测量结果，L组的旋转角度、远侧移位和背侧蹄壁厚度均大于N组；前肢蹄壁厚度大于后肢；使用MR成像测量的远侧移位和蹄壁厚度小于X线摄影，但模式相似。结论是，使用MR成像可始终观察到慢性蹄叶炎的特征，且这些特征可能是X线摄影观察到的特征之外的补充。
