Departments of Ophthalmology (BSC, MYL, BBB, JHL, RAS, NJN, VB), Radiology and Imaging Sciences (SA, AMS), Epidemiology (BBB), Neurology (BBB, NJN, VB), and Neurological Surgery (NJN), Emory University, Atlanta, Georgia.
J Neuroophthalmol. 2021 Dec 1;41(4):e464-e469. doi: 10.1097/WNO.0000000000000986.
The tortuosity of the optic nerve can be quantified radiologically by measuring the angle of optic nerve deformation (the "optic nerve angle" [ONA]). In patients with idiopathic intracranial hypertension (IIH), lowering the intracranial pressure (ICP) to a normal range by lumbar puncture leads to straightening of the optic nerve and an increase in the measured sagittal ONA on MRI. It is uncertain whether there is any correlation between ONA and cerebrospinal fluid (CSF) opening pressure or visual function.
Retrospective study of patients with and without IIH who had MRI of the brain followed by lumbar puncture with CSF opening pressure within 24 hours of MRI. Before LP and within 24 hours of MRI of the brain, all patients with IIH had neuro-ophthalmologic assessment including visual acuity, Humphrey Visual Field (HVF), and fundus photography. Sagittal ONA was measured on multiplanar T2-SPACE images on a DICOM viewer. Papilledema on the fundus photographs was graded using the Frisén scale.
Fifty-four patients with IIH and 30 unmatched controls were included. The IIH group was 6.3 years younger (95% CI 2.4-10.3, P = 0.002), had 8.7 kg/m2 higher body mass index (4.9-12.5, P < 0.001), and 26.3% more women (P = 0.011) compared with controls. In both eyes, the ONA was significantly smaller in patients with IIH by 12° compared with controls (7°-17°, P < 0.00001). In the IIH group, no correlation between ONA and the CSF opening pressure was present in either eye (right eye r = 0.19, P = 0.15; left eye r = 0.18, P = 0.19) The ONA did not correlate with logarithm of the minimum angle of resolution visual acuity (right eye r = 0.26, P = 0.063; left eye r = 0.15, P = 0.27), HVF mean deviation (right eye r = 0.0059, P = 0.97; left eye r = -0.069, P = 0.63), or Frisén grade (Spearman's rho right eye 0.058, P = 0.67; left eye 0.14, P = 0.30).
The ONA is significantly smaller in patients with IIH compared to controls, but does not correlate with CSF opening pressure, severity of papilledema, or visual function. The ONA may be useful in identifying patients with raised ICP, but not necessarily those with a poor visual prognosis.
视神经的迂曲度可以通过测量视神经变形角度（“视神经角度”[ONA]）来放射学量化。在特发性颅内高压（IIH）患者中，通过腰椎穿刺将颅内压降低到正常范围会导致视神经变直，并增加 MRI 上测量的矢状面 ONA。ONA 与脑脊液（CSF）开放压或视觉功能之间是否存在任何相关性尚不确定。
对有和无 IIH 的患者进行回顾性研究，这些患者在 MRI 后 24 小时内进行了腰椎穿刺并测量了 CSF 开放压。在 LP 之前和 MRI 后 24 小时内，所有 IIH 患者均进行了神经眼科评估，包括视力、Humphrey 视野（HVF）和眼底摄影。在 DICOM 查看器上的多平面 T2-SPACE 图像上测量矢状面 ONA。眼底照片上的视盘水肿使用 Frisén 量表进行分级。
共纳入 54 例 IIH 患者和 30 例未匹配的对照组。IIH 组比对照组年轻 6.3 岁（95%CI 2.4-10.3，P=0.002），体重指数（BMI）高 8.7kg/m2（4.9-12.5，P<0.001），女性比例高 26.3%（P=0.011）。双眼 ONA 在 IIH 患者中均比对照组小 12°（7°-17°，P<0.00001）。在 IIH 组中，双眼 ONA 与 CSF 开放压之间均无相关性（右眼 r=0.19，P=0.15；左眼 r=0.18，P=0.19）。ONA 与最小角分辨率视力的对数（右眼 r=0.26，P=0.063；左眼 r=0.15，P=0.27）、HVF 平均偏差（右眼 r=0.0059，P=0.97；左眼 r=-0.069，P=0.63）或 Frisén 分级（右眼 Spearman 相关系数 0.058，P=0.67；左眼 0.14，P=0.30）均无相关性。
与对照组相比，IIH 患者的 ONA 明显较小，但与 CSF 开放压、视盘水肿严重程度或视觉功能均无相关性。ONA 可能有助于识别颅内压升高的患者，但不一定是预后不良的患者。
