Ishizaka Hiroshi, Naka Minoru, Nagase Hiroyuki, Yanagisawa Katsumi, Kubota Toshio, Morita Hideo, Tsushima Yoshito
Department of Radiology, Maebashi Red Cross Hospital, Gunma, Japan.
Department of Diagnostic Radiology and Nuclear Medicine, Graduate School of Medicine, Gunma University, Gunma, Japan.
Acta Radiol Open. 2020 Jan 27;9(1):2058460120902406. doi: 10.1177/2058460120902406. eCollection 2020 Jan.
There is no standardized brain computed tomography (CT) reference line that can be determined on both scout and reformatted sagittal CT images. Here, a tangential line from the anterior edge of the lower eyelid to the inner table of the occipital base (LEL/O line) appears nearly parallel to the Talairach-Tournoux (T/T) line, which shows a consistent intracranial anatomical relationship among subjects, and acts as a standard reference line for magnetic resonance (MR) imaging.
To quantitatively validate the LEL/O line as a new standard brain CT reference line.
We measured: angle 1 = the LEL/O line on scout images from the LEL/O line on parasagittal CT images (n=93); and angle 2 = the LEL/O line on scout images from the T/T line on high resolution midsagittal MR images (n=97). Angles in a clockwise direction were defined as positive and were expressed as mean±SD with the 95% confidence interval (CI) of the SD. Angle 2 was measured independently by two observers and intraclass correlation coefficients (ICCs) were calculated.
Angle 1 was -0.4°±1.2° (95% CI of SD 1.1°-1.5°); angle 2 was -0.4°±2.0° (95% CI of SD, 1.8°-2.4°). The ICC in the angle 2 measurement was 0.780 (<0.001), which indicated high inter-observer reliability.
The LEL/O lines on scout and parasagittal CT images show practically the same gradient, and these LEL/O lines are almost parallel to the T/T line. Use of the LEL/O line either for direct scanning or reformation can minimize intra- and inter-subject variations on CT images and mismatch between CT and MR images.
目前尚无一种能在定位像和矢状面重组CT图像上均能确定的标准化脑CT参考线。在此，一条从下眼睑前缘至枕骨基底内板的切线（LEL/O线）似乎与Talairach-Tournoux（T/T）线近乎平行，T/T线在不同受试者间显示出一致的颅内解剖关系，并且是磁共振（MR）成像的标准参考线。
定量验证LEL/O线作为一种新的标准脑CT参考线。
我们测量了：角度1 = 定位像上的LEL/O线与矢状旁位CT图像上的LEL/O线之间的夹角（n = 93）；以及角度2 = 定位像上的LEL/O线与高分辨率正中矢状面MR图像上的T/T线之间的夹角（n = 97）。顺时针方向的角度定义为正值，并表示为平均值±标准差以及标准差的95%置信区间（CI）。角度2由两名观察者独立测量，并计算组内相关系数（ICC）。
角度1为-0.4°±1.2°（标准差的95%CI为1.1° - 1.5°）；角度2为-0.4°±2.0°（标准差的95%CI为1.8° - 2.4°）。角度2测量中的ICC为0.780（<0.001），这表明观察者间可靠性高。
定位像和矢状旁位CT图像上的LEL/O线显示出几乎相同的斜率，并且这些LEL/O线几乎与T/T线平行。将LEL/O线用于直接扫描或重组可使CT图像上的受试者内和受试者间差异以及CT与MR图像之间的不匹配最小化。
