Tan Tock Seng Hospital, Singapore.
Ann Acad Med Singap. 2009 Sep;38(9):821-6.
The Optic Neuritis Treatment Trial (ONTT) has established that the magnetic resonance imaging (MRI) findings at the time of presentation of optic neuritis (ON) is the strongest indicator of the development of multiple sclerosis (MS). Reports from Singapore as well as other Asian countries have indicated that these abnormalities are less frequently encountered compared to that reported by the ONTT. This paper aims to describe systematically the brain MRI as well as the optic nerve abnormalities in patients after an episode of acute optic neuritis.
Patients who presented with acute optic neuritis were retrieved from our prospective optic neuritis study and their MRI scans were reviewed and graded in accordance with the standardised classification employed in the ONTT.
Fifteen of 24 patients had MRI brain and optic nerves performed during the acute episode. In the evaluation of brain abnormalities, 40% were classified as grade 0, 20% grade I, 20% grade II, 6.7% grade III and 13.3% grade IV. Optic nerve abnormalities were observed in 80% of cases. At study entry, 10 patients had idiopathic (monosymptomatic) ON, 3 had multiple sclerosis (MS), one each with infective and autoimmune optic neuritis, respectively. The single patient who developed MS at study completion presented with grade II brain abnormalities at the initial MRI. For those with idiopathic ON, our study revealed a higher percentage of grade 0-I brain changes as well as a lower lesion load compared to the ONTT.Lesion Load and grade was also lower in anterior optic neuritis compared with retrobulbar disease.
Our study revealed a lower percentage of grade II-IV brain MRI abnormalities as well as less lesion load in idiopathic ON compared to the ONTT. This may be related to the lower prevalence of MS in our predominantly Asian population. As diagnostic tests and understanding of neuromyelitis optica or Devic's disease improves, we may see more patients being diagnosed with this condition, which may also explain our findings. Our data also showed that MRI grade and lesion load in cases of anterior ON was lower than for retrobulbar disease. MRI in ON has an essential role in characterising the disease, evaluating for associated brain lesions, and assessing prognosis in retrobulbar disease but may be less useful in anterior disease.
视神经炎治疗试验（ONTT）已经证实，视神经炎（ON）发病时的磁共振成像（MRI）表现是多发性硬化（MS）发展的最强指标。来自新加坡和其他亚洲国家的报告表明，与 ONTT 报告相比，这些异常情况较少见。本文旨在系统描述急性视神经炎后患者的脑 MRI 以及视神经异常。
从我们的前瞻性视神经炎研究中检索出出现急性视神经炎的患者，并根据 ONTT 中使用的标准化分类对其 MRI 扫描进行回顾性评估和分级。
在 24 名患者中，有 15 名在急性发作期间进行了脑和视神经 MRI 检查。在评估脑异常时，40%被归类为 0 级，20%为 1 级，20%为 2 级，6.7%为 3 级，13.3%为 4 级。80%的病例观察到视神经异常。在研究入组时，10 名患者为特发性（单症状）ON，3 名为多发性硬化症（MS），分别有 1 名患者为感染性和自身免疫性视神经炎。在研究结束时发展为 MS 的唯一患者在初始 MRI 中表现为 2 级脑异常。对于特发性 ON 患者，我们的研究显示脑变化的 0-1 级比例较高，病变负荷也低于 ONTT。与球后疾病相比，前部视神经炎的病变负荷和分级也较低。
与 ONTT 相比，我们的研究显示特发性 ON 的 2-4 级脑 MRI 异常和病变负荷较低。这可能与我们主要是亚洲人群中 MS 的患病率较低有关。随着对神经髓鞘炎或 Devic 病的诊断测试和理解的提高，我们可能会看到更多的患者被诊断为这种疾病，这也可能解释了我们的发现。我们的数据还表明，前部 ON 病例的 MRI 分级和病变负荷低于球后疾病。ON 的 MRI 在描述疾病、评估相关脑病变以及评估球后疾病的预后方面具有重要作用，但在前部疾病中可能作用不大。
