Alperin N, Bagci A M, Lam B L, Sklar E
Department of Radiology.
AJNR Am J Neuroradiol. 2013 Dec;34(12):2354-9. doi: 10.3174/ajnr.A3600. Epub 2013 Jun 6.
Subjective determination of the posterior sclera flattening and optic nerve protrusion in MRI is challenging because of the 3D nature of the globe morphology. This study aims to develop and compare quantitative measures of globe flattening and optic nerve protrusion with subjective rating, and assess relationships with papilledema grade and intraocular and CSF pressures.
Data of 34 globes from 7 overweight female patients with idiopathic intracranial hypertension and 6 age- and weight-matched healthy female control subjects were assessed, as well as a subcohort of 4 of the patients with idiopathic intracranial hypertension who underwent follow-up MR imaging 2 weeks after lumbar puncture and initiation of treatment with acetazolamide. MR imaging examination included a 3D CISS sequence on 1.5T and 3T scanners with 0.6-mm isotropic resolution. Subjective ratings of globe flattening were obtained by experienced and inexperienced readers. Quantitative measures of globe flattening, nerve protrusion, and maximal deformation were derived by use of a 2D map of the distances from the globe center to the posterior wall.
Contingency coefficients for globe flattening agreements with subjective rating by the experienced and inexperienced readers were 0.72 and 0.56, respectively. Mean values of the 3 deformation measures were significantly poorer in the idiopathic intracranial hypertension group, with nerve protrusion demonstrating the strongest difference (P = .0002). Nerve protrusion was most strongly associated with papilledema grade with a contingency coefficient of 0.74 (P = .01), whereas globe flattening was negatively correlated with intraocular pressure (R = -0.75, P < .0001). Maximal deformation was negatively associated with CSF opening pressure (R = -0.86, P = .0001). After treatment, only the changes in nerve protrusion and maximal deformation were significant.
Automated measures of globe deformation improve reliability over subjective rating. Of the 2 globe deformation measures, nerve protrusion had the strongest predictive value for papilledema grade and had the highest sensitivity for assessment of treatment efficacy in idiopathic intracranial hypertension.
由于眼球形态的三维特性，在磁共振成像（MRI）中主观判断后巩膜扁平及视神经突出具有挑战性。本研究旨在开发并比较眼球扁平及视神经突出的定量测量方法与主观评分，并评估其与视乳头水肿分级、眼压及脑脊液压力的关系。
评估了7例超重女性特发性颅内高压患者和6例年龄及体重匹配的健康女性对照受试者的34只眼球的数据，以及4例特发性颅内高压患者的亚组数据，这些患者在腰椎穿刺及开始用乙酰唑胺治疗2周后接受了随访磁共振成像检查。磁共振成像检查包括在1.5T和3T扫描仪上采用0.6毫米各向同性分辨率的三维稳态构成干扰序列（3D CISS序列）。由经验丰富和经验不足的阅片者对眼球扁平进行主观评分。通过使用从眼球中心到后壁距离的二维图得出眼球扁平、神经突出及最大变形的定量测量值。
经验丰富和经验不足的阅片者对眼球扁平与主观评分一致性的列联系数分别为0.72和0.56。特发性颅内高压组的3种变形测量平均值明显较差，神经突出表现出最强差异（P = 0.0002）。神经突出与视乳头水肿分级关联最强，列联系数为0.74（P = 0.01），而眼球扁平与眼压呈负相关（R = -0.75，P < 0.0001）。最大变形与脑脊液开放压呈负相关（R = -0.86，P = 0.0001）。治疗后，只有神经突出和最大变形的变化具有显著性。
眼球变形的自动测量方法比主观评分提高了可靠性。在两种眼球变形测量方法中，神经突出对视乳头水肿分级具有最强的预测价值，并对评估特发性颅内高压的治疗效果具有最高的敏感性。
