There is no available measuring protocol and reference range for the normal canine trigeminal nerve. This can be problematic in cases of suspected bilateral trigeminal neuropathy since contralateral nerves cannot be a usefully compared. Trigeminal nerves and brain measurements were retrospectively assessed via multiplanar reconstruction (MPR) of 3DT1 post-contrast MR sequences from 137 dogs with no signs or diagnosis of trigeminal disease. Direct measurements of vertical brain height (BH), trigeminal nerves transverse height (TTH) and trigeminal nerves width in dorsal reconstruction (TDW) were made in a plane immediately caudal to the foramen ovale and used to derive trigeminal nerve-to-brain (NB) ratios, including height-to-brain ratio (HBR) and width-to-brain ratio (WBR). HBR (0.09, IQR = 0.08-0.09) and WBR (0.10, IQR = 0.09-0.11) maintained more consistent values across the study population compared to direct measurements of TTH (3.72, IQR = 3.42-4.07) and TDW (4.35 +/- 0.63). Calculated normal reference intervals for HBR and WBR were 0.07-0.11 and 0.08-0.13, respectively and the largest NB ratios recorded in normal dogs were 0.13 and 0.14 for HBR and WBR, respectively. All measurements varied proportionally with weight, including HBR (r = 0.41, p < 0.0001) and small dogs had a significantly smaller HBRs compared to medium (p = 0.0294), large (p < 0.0049) and giant dogs (p < 0.0044). Median HBR was the same across skull types (0.09), however post-hoc analysis detected significantly smaller HBRs in brachycephalic compared to mesaticephalic dogs (p = 0.0494). In conclusion, trigeminal NB ratios may allow for accurate, objective assessment of the canine trigeminal nerves on MRI but further quantification of the effects of weight and skull type on suggested reference intervals is needed.

中文翻译：

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正常犬三叉神经的低场MRI测量。

正常的犬三叉神经没有可用的测量方案和参考范围。在怀疑双侧三叉神经病变的情况下，这可能会产生问题，因为对侧神经无法进行有效比较。通过多平面重建（MPR）对137只无三叉神经疾病体征或诊断的狗的3DT1造影剂后MR序列进行回顾性评估，以评估三叉神经和大脑的测量结果。直接在卵圆孔尾部尾端的平面中直接测量垂直大脑高度（BH），三叉神经横行高度（TTH）和三叉神经在背侧重建中的宽度（TDW），并用于得出三叉神经到脑）比，包括高脑比（HBR）和宽脑比（WBR）。HBR（0.09，IQR = 0.08-0.09）和WBR（0.10，IQR = 0.09-0）。11）与直接测量TTH（3.72，IQR = 3.42-4.07）和TDW（4.35 +/- 0.63）相比，在研究人群中保持了更一致的值。计算得出的HBR和WBR正常参考间隔分别为0.07-0.11和0.08-0.13，正常狗中记录的最大NB比对于HBR和WBR分别为0.13和0.14。所有测量值均随体重成比例变化，包括HBR（r = 0.41，p <0.0001），与中型（p = 0.0294），大型（p <0.0049）和大型犬（p <0.0044）相比，小型犬的HBR明显更小。颅骨类型之间的中位HBR值相同（0.09），但是事后分析发现，与中头狗相比，近端头颅的HBR明显更小（p = 0.0494）。总而言之，三叉戟的NB比例可能允许准确，