Zealley I A, Cooper R C, Clifford K M, Campbell R S, Potterton A J, Zammit-Maempel I, Baudouin C J, Coulthard A
Department of Radiology, Freeman Hospital, Newcastle upon Tyne, England.
Br J Radiol. 2000 Mar;73(867):242-7. doi: 10.1259/bjr.73.867.10817038.
Gadolinium enhanced MRI is the gold standard investigation for the detection of acoustic neuroma. Non-contrast MRI sequences have been suggested as an alternative for screening examinations. In order to determine the utility of fast spin echo imaging, both gadolinium enhanced T1 weighted images and fast spin echo T2 weighted images were acquired in 1233 consecutive patients referred for exclusion of acoustic neuroma. Two radiologists independently recorded their findings. Fast spin echo T2 weighted images were evaluated with respect to the visibility of nerves within the internal auditory canals and allocated a confidence score for the presence or absence of acoustic neuroma. 33 acoustic neuromas were identified. Only 56% were confidently identified on fast spin echo T2 weighted images alone; gadolinium enhanced T1 weighted images were required to confirm the diagnosis in 44% of the cases, including 9 of the 10 intracanalicular tumours. However, when identification of two normal intracanalicular nerves is employed as the criterion of normality, the single fast spin echo T2 weighted sequence excluded acoustic neuroma in 59% of this screened population. It is concluded that an imaging strategy intended to identify small intracanalicular acoustic neuromas cannot rely on fast spin echo T2 weighted imaging alone. Gadolinium enhanced T1 weighted imaging could be restricted to patients where fast spin echo images do not exclude acoustic neuroma but this strategy requires continuous supervision by an experienced radiologist. In most practices the screening examination should continue to include a gadolinium enhanced sequence in order to optimize the detection of small acoustic neuromas.
钆增强磁共振成像（MRI）是检测听神经瘤的金标准检查方法。非增强MRI序列已被建议作为筛查检查的替代方法。为了确定快速自旋回波成像的效用，对1233例连续转诊以排除听神经瘤的患者同时采集了钆增强T1加权图像和快速自旋回波T2加权图像。两位放射科医生独立记录他们的发现。对快速自旋回波T2加权图像进行评估，观察内听道内神经的可见性，并为是否存在听神经瘤分配一个置信度评分。共识别出33例听神经瘤。仅在快速自旋回波T2加权图像上能明确识别的仅占56%；44%的病例需要钆增强T1加权图像来确诊，其中包括10例管内型肿瘤中的9例。然而，当以识别两条正常的内听道神经作为正常标准时，单一的快速自旋回波T2加权序列在59%的筛查人群中排除了听神经瘤。结论是，旨在识别小管内型听神经瘤的成像策略不能仅依赖于快速自旋回波T2加权成像。钆增强T1加权成像可仅限于快速自旋回波图像不能排除听神经瘤的患者，但这种策略需要有经验的放射科医生持续监督。在大多数实际操作中，筛查检查应继续包括钆增强序列，以优化小听神经瘤的检测。
