Department of Radiology and Imaging Sciences (RH, DQ, JO, and AMS), Emory University School of Medicine, Atlanta, Georgia; Northside Radiology Associates (JH), Atlanta, Georgia; and Department of Ophthalmology (NJN, VB, BBB), Emory University School of Medicine, Atlanta, Georgia.
J Neuroophthalmol. 2019 Mar;39(1):35-40. doi: 10.1097/WNO.0000000000000643.
Optic nerve sheath tortuosity is a previously reported, but incompletely characterized, finding in idiopathic intracranial hypertension (IIH). We hypothesized that optic nerve angle (ONA), as a quantitative measure of tortuosity, would change dynamically with cerebrospinal fluid (CSF) pressure status of patients with IIH immediately before and after lumbar puncture (LP).
Consecutive patients with suspected IIH referred for MRI and diagnostic LP were prospectively enrolled in this single institution, institutional review board-approved study. Each patient underwent a pre-LP MRI, diagnostic LP with opening pressure (OP) and closing pressure (CP), and then post-LP MRI all within 1 session. Sagittal and axial ONAs were measured on multiplanar T2 SPACE images by 2 neuroradiologists on pre- and post-LP MRI. Effects of measured pressure and CSF volume removal on changes in ONA were analyzed as was interrater reliability for ONA measurement.
Ten patients with IIH were included {all female, median age 29 (interquartile range [IQR] 25-32)}. All patients had elevated OP (median 37, IQR 34-41 cm H2O), and significantly reduced CP (median 18, IQR 16-19 cm H2O, P < 0.001) after CSF removal (IQR 13-16 mL). Within patients, mean ONAs (sagittal and axial) were significantly lower before (162 ± 9°, 163 ± 10°) than after (168 ± 7°, 169 ± 5°) LP (P = 0.001, 0.008, respectively). Interrater reliability was higher with sagittal ONA measurements (0.89) than axial (0.72).
ONA changes with short-term CSF pressure reduction in patients with IIH, establishing optic nerve tortuosity as a dynamic process related to CSF status.
视神经鞘迂曲是特发性颅内高压（IIH）的一种先前报道但不完全特征化的表现。我们假设，视神经角度（ONA）作为迂曲的定量测量，将在 IIH 患者腰椎穿刺（LP）前后的脑脊液（CSF）压力状态下发生动态变化。
连续纳入疑似 IIH 并转介行 MRI 和诊断性 LP 的患者，进行前瞻性单中心、机构审查委员会批准的研究。每位患者在 1 次就诊中，先后进行 LP 前 MRI、有开放压（OP）和关闭压（CP）的诊断性 LP，然后进行 LP 后 MRI。多平面 T2 SPACE 图像上的矢状面和轴面 ONAs 由 2 位神经放射科医生在 LP 前和 LP 后 MRI 上进行测量。分析测量压力和 CSF 体积去除对 ONA 变化的影响，以及 ONA 测量的组内可靠性。
10 例 IIH 患者入选（均为女性，中位年龄 29 岁（四分位距 [IQR] 25-32））。所有患者 OP 升高（中位 37，IQR 34-41 cm H2O），CSF 去除后 CP 明显降低（中位 18，IQR 16-19 cm H2O，P < 0.001）。在患者内部，平均 ONAs（矢状面和轴面）LP 前（162 ± 9°，163 ± 10°）明显低于 LP 后（168 ± 7°，169 ± 5°）（P = 0.001，0.008）。矢状面 ONA 测量的组内可靠性高于轴面（0.89 比 0.72）。
IIH 患者短期 CSF 压力降低时 ONA 发生变化，证实视神经迂曲是与 CSF 状态相关的动态过程。
