Shariat Razavi I, Amezic V, Zucconi F, Cova M A, Pozzi Mucelli R
Istituto di Radiologia dell'Università, Ospedale di Cattinara, Trieste.
Radiol Med. 1997 Jun;93(6):662-8.
The most common fat-suppressed sequence used to study skeletal conditions is the STIR sequence which has shown high sensitivity in the detection of skeletal lesions and whose main drawback is its long acquisition time. Currently, Turbo-STIR (T-STIR) sequences can shorten the acquisition time. The purpose of this study was therefore to compare the conventional STIR sequence with the new T-STIR sequence in the study of skeletal conditions to compare their diagnostic yield.
Twenty patients with different types of skeletal lesions were examined. MR examinations were performed with a Philips Gyroscan S15/ACS II unit (1.5 T). All the patients underwent a STIR sequence (TR/TE = 1500/20, TI = 180 ms, matrix = 204 x 256, NEX = 2, slice thickness = 5 mm, acquisition time = 9 min 24 s) and a T-STIR sequence (TR/TE = 1500/20, TI = 180 ms, matrix = 204 x 256, NEX = 2, slice thickness = 5 mm, TFL = 3, acquisition time = 3 min 33 s). The images were evaluated by measuring both quantitative parameters--percent contrast (%C), contrast to noise ratio (C/N), signal to noise ratio (S/N)--and qualitative parameters--lesion conspicuity, margins and extension, motion artifacts, image quality.
The only statistically significant difference between the two sequences was image quality, which was superior in the conventional STIR sequence (p < .05). No statistically significant difference was demonstrated with the quantitative evaluation.
In this study, T-STIR sequences were performed with low-high acquisition profile to acquire an actual echo time of 20 ms which permits to obtain optimal S/N with good spatial resolution. Therefore, T-STIR sequences with low-high acquisition profile provides better results than T-STIR sequences with linear acquisition profile which permits to obtain an actual echo time of 40 ms.
This work shows that T-STIR sequences can replace conventional STIR sequences in the study of skeletal conditions reducing the acquisition time by 60%. This result can be obtained only by an accurate optimization of acquisition parameters.
用于研究骨骼疾病的最常见脂肪抑制序列是短TI反转恢复（STIR）序列，它在检测骨骼病变方面具有高灵敏度，其主要缺点是采集时间长。目前，快速自旋回波短TI反转恢复（T-STIR）序列可以缩短采集时间。因此，本研究的目的是在骨骼疾病研究中比较传统STIR序列和新的T-STIR序列，以比较它们的诊断效能。
对20例患有不同类型骨骼病变的患者进行检查。使用飞利浦Gyroscan S15/ACS II设备（1.5T）进行磁共振成像（MR）检查。所有患者均接受STIR序列（TR/TE = 1500/20，TI = 180 ms，矩阵 = 204×256，激励次数 = 2，层厚 = 5 mm，采集时间 = 9分24秒）和T-STIR序列（TR/TE = 1500/20，TI = 180 ms，矩阵 = 204×256，激励次数 = 2，层厚 = 5 mm，TFL = 3，采集时间 = 3分33秒）。通过测量定量参数——对比度百分比（%C）、对比噪声比（C/N）、信噪比（S/N）——和定性参数——病变清晰度、边界及范围、运动伪影、图像质量来评估图像。
两种序列之间唯一具有统计学意义的差异是图像质量，传统STIR序列的图像质量更优（p < 0.05）。定量评估未显示出统计学意义上的差异。
在本研究中，T-STIR序列采用低-高采集模式以获得实际回波时间为20 ms，这允许在良好的空间分辨率下获得最佳信噪比。因此，具有低-高采集模式的T-STIR序列比允许获得实际回波时间为40 ms的线性采集模式的T-STIR序列提供更好的结果。
这项工作表明，在骨骼疾病研究中，T-STIR序列可以替代传统STIR序列，将采集时间缩短60%。只有通过精确优化采集参数才能获得这一结果。
