Yoshikawa K, Okada Y, Minami M, Itoh M, Aoki S, Ohtomo K, Iio M
Radiat Med. 1985 Oct-Dec;3(4):214-24.
It is difficult to recognize signal intensity changes on spin echo (SE) images. Clinically both T1-weighted and T2-weighted images are now used in most institutions to evaluate signal intensity changes due to different T1 and T2 of the lesions in MRI. However, these are not sufficient to understand signal intensity changes completely. The authors attempted to summarize on a two-dimensional graph the effects of T1, T2, proton density, and imaging parameters that influence signal intensities on SE images. Both end point (E) and start point (S), as defined later, depended mainly on proton density, but the former also depended on T2 and the later on T1 value. The image obtained in the former situation (near point E) was then called the T2-weighted image. Conditions to accelerate recovery and attenuation velocities (VR and VA), also mentioned later, were the same as those that increased points E and S, respectively. However, when TR was relatively short, the effect of a shorter T1 on VR was greatly emphasized. Such an image was then called the T1-weighted image.
在自旋回波（SE）图像上识别信号强度变化较为困难。临床上，目前大多数机构都使用T1加权像和T2加权像来评估MRI中病变因不同的T1和T2而产生的信号强度变化。然而，这些还不足以完全理解信号强度变化。作者试图在二维图上总结T1、T2、质子密度以及影响SE图像信号强度的成像参数的作用。如下文所定义的终点（E）和起点（S），主要取决于质子密度，但前者也取决于T2，后者取决于T1值。在前者情况（接近点E）下获得的图像随后被称为T2加权像。下文还提到的加速恢复和衰减速度（VR和VA）的条件，分别与增加点E和S的条件相同。然而，当TR相对较短时，较短的T1对VR的影响会被极大地凸显出来。这样的图像随后被称为T1加权像。
