Diffusion tensor imaging in cases with visual field defect after anterior temporal lobectomy.
Diffusion tensor imaging in cases with visual field defect after anterior temporal lobectomy.
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发表时间：
2005-04
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通讯作者：
T. Taoka;M. Sakamoto;S. Iwasaki;H. Nakagawa;A. Fukusumi;S. Hirohashi;Keiko Taoka;K. Kichikawa;T. Hoshida;T. Sakaki
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作者：
T. Taoka;M. Sakamoto;S. Iwasaki;H. Nakagawa;A. Fukusumi;S. Hirohashi;Keiko Taoka;K. Kichikawa;T. Hoshida;T. Sakaki
背景和目的视辐射损伤引起的视力缺陷是颞叶切除术治疗颞叶癫痫的并发症。为了研究弥散张量成像是否可以描绘肺叶切除术后视辐射的变化，我们评估了视辐射张量图像的参数并将其与视觉缺陷相关联。方法 我们检查了 14 例颞叶切除术后的病例。手术后的持续时间从 3 周到 9 年不等。根据视野缺损的严重程度将病例分为三组（A-C，其中C组最严重）。我们评估了手术侧和完好侧视辐射的 T2 加权图像信号和张量图像参数，包括分数各向异性 (FA) 和表观扩散系数 (ADC)。结果 在 T2 加权图像上，4 例患者在术后 4 周以上出现视辐射高信号。视辐射中手术侧与完整侧 FA 的平均比率根据视觉缺陷的严重程度而降低（A 组，0.88；B 组，0.89；C 组，0.73）。总体病例中手术侧与完整侧 ADC 的平均比率没有显着差异。然而，术后 10 周后，根据视力缺陷情况，ADC 的比率趋于增加。结论 颞叶切除术后病例的光辐射显示 FA 值降低。在后期，ADC 值趋于增加，并且在 T2 加权图像上观察到高信号强度。即使在术后早期，FA 值也可用于评估视辐射的沃勒变性。
BACKGROUND AND PURPOSE Visual defect due to optic radiation injury is a complication of temporal lobectomy for temporal epilepsy. To investigate whether diffusion tensor imaging can delineate the changes in optic radiations after lobectomy, we evaluated parameters on tensor images for optic radiations and correlated them with visual defect. METHODS We examined 14 cases after temporal lobectomy. Durations after surgeries ranged from 3 weeks to 9 years. The cases were classified into three groups on the basis of the severity of visual field defect (A-C, with group C the most severe). We evaluated signals on T2-weighted images and parameters of tensor images, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC), for the optic radiation in both the operated and intact side. RESULTS On T2-weighted images, high signals in optic radiations were seen in four cases, occurring more than 4 weeks after surgery. The mean operated-to-intact side FA ratio in the optic radiation decreased according to severity of visual defect (group A, 0.88; group B, 0.89; group C, 0.73). The mean operated-to-intact side ADC ratio showed no significant difference in the overall cases. The ratio for ADC, however, tended to increase according to visual defect in cases after 10 weeks postsurgery. CONCLUSION Optic radiation showed a decreased FA value in cases after temporal lobectomy. In later stages, ADC values tended to increase and high signal intensities on T2-weighted images were observed. The FA value can be used for evaluating Wallerian degeneration of optic radiation even in the early stages after surgery.