Scrivani Peter V, Fletcher Daniel J, Cooley Stacy D, Rosenblatt Alana J, Erb Hollis N
Department of Clinical Sciences, Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA.
Vet Radiol Ultrasound. 2013 May-Jun;54(3):263-70. doi: 10.1111/vru.12023. Epub 2013 Mar 7.
Intracranial hypertension is a cause of cerebral ischemia and neurologic deficits in dogs. Goals of this retrospective study were to test interobserver agreement for MRI measurements of optic nerve sheath diameter and associations between optic nerve sheath diameter, signalment data, and presumed intracranial hypertension status in a cohort of dogs. A veterinary radiologist interpreted scans of 100 dogs and dogs were assigned to groups based on presence or absence of at least two MRI characteristics of presumed intracranial hypertension. Two observers who were unaware of group status independently measured optic nerve diameter from transverse T2-weighted sequences. Mean optic nerve sheath diameter for all dogs was 3 mm (1-4 mm). The mean difference between observers was 0.3 mm (limits of agreement, -0.4 and 1.0 mm). There was no correlation between optic nerve sheath diameter and age for either observer (r = -0.06 to 0.00) but a moderate positive correlation was observed between optic nerve sheath diameter and body weight for both observers (r = 0.70-0.76). The 22 dogs with presumed intracranial hypertension weighed less than the 78 dogs without (P = 0.02) and were more often female (P = 0.04). Dogs with presumed intracranial hypertension had a larger ratio of optic nerve sheath diameter to body weight for each observer-side pair (P = 0.01-0.04) than dogs without. Findings indicated that the ratio of MRI optic nerve sheath diameter relative to body weight may be a repeatable predictor of intracranial hypertension in dogs.
颅内高压是犬脑缺血和神经功能缺损的一个原因。这项回顾性研究的目的是检验在一组犬中，观察者之间对视神经鞘直径MRI测量的一致性，以及视神经鞘直径、特征数据和假定颅内高压状态之间的关联。一名兽医放射科医生解读了100只犬的扫描结果，并根据是否存在至少两种假定颅内高压的MRI特征将犬分组。两名不知分组情况的观察者独立从横向T2加权序列测量视神经直径。所有犬的平均视神经鞘直径为3毫米（1 - 4毫米）。观察者之间的平均差异为0.3毫米（一致性界限为 -0.4和1.0毫米）。两名观察者的视神经鞘直径与年龄均无相关性（r = -0.06至0.00），但两名观察者的视神经鞘直径与体重均存在中度正相关（r = 0.70 - 0.76）。22只假定有颅内高压的犬比78只无颅内高压的犬体重轻（P = 0.02），且雌性更多（P = 0.04）。对于每对观察者 - 侧别组合，假定有颅内高压的犬的视神经鞘直径与体重之比均大于无颅内高压的犬（P = 0.01 - 0.04）。研究结果表明，MRI视神经鞘直径与体重之比可能是犬颅内高压的一个可重复的预测指标。
