Hergan K, Doringer W, Oser W
Zentrales Institut für Radiologie, LKH Feldkirch, Osterreich.
Rofo. 1998 Jul;169(1):11-6. doi: 10.1055/s-2007-1015042.
The aim of the retrospective study was to determine whether subtraction of spin-echo images is useful for estimating intensity and extension of contrast enhancement when practised in daily routine diagnostic work.
348 patients with different diseases of the musculoskeletal and neuro system were examined with MRI using a T1-weighted spin-echo sequence before and after application of 0.1 mmol/kg Gd-DTPA with subsequent subtraction of both measurements. Usefulness of the source images, pictorial quality of subtracted images and intensity of contrast enhancement were assessed subjectively.
Subtracted images were of sufficient quality in 85% of the cases, whereas source images were always usable except in 9 patients. It was easier to visualise the extent of contrast enhancement in subtracted than in non-subtracted images in examinations of the musculoskeletal system, whereas there was no difference in the neuro system. Contrast enhancement could definitely be excluded in 15% of the patients and was stated to be of low, medium and high intensity in 21%, 45% and 19%, respectively. In comparison with subtracted images lesions were stated to appear larger in 62% and 87%, smaller in 25% and 13%, and of the same size in 13% and 0% for T2-weighted and fat-suppressed images, respectively.
Subtraction of spin-echo images before and after application of contrast media is useful for estimating intensity and extension of contrast enhancement without essentially increasing time and costs of the examination. Extension of contrast enhancement in musculoskeletal lesions rarely correlates with the extension of signal changes in T2-weighted and fat-suppressed images.
这项回顾性研究的目的是确定在日常诊断工作中进行自旋回波图像相减是否有助于评估对比增强的强度和范围。
对348例患有肌肉骨骼和神经系统不同疾病的患者进行MRI检查，在静脉注射0.1 mmol/kg钆喷酸葡胺前后采用T1加权自旋回波序列成像，随后将两次测量结果相减。主观评估原始图像的实用性、相减后图像的图像质量以及对比增强的强度。
85%的病例中相减后图像质量足够，而原始图像除9例患者外均可用。在肌肉骨骼系统检查中，相减后图像比未相减图像更容易观察到对比增强的范围，而在神经系统检查中两者无差异。15%的患者可明确排除对比增强，21%、45%和19%的患者分别显示为低、中、高强度的对比增强。与相减后图像相比，T2加权图像和脂肪抑制图像中分别有62%和87%的病变显示更大，25%和13%的病变显示更小，13%和0%的病变显示大小相同。
在注射对比剂前后进行自旋回波图像相减，有助于评估对比增强的强度和范围，且基本不会增加检查时间和成本。肌肉骨骼病变的对比增强范围很少与T2加权图像和脂肪抑制图像中的信号变化范围相关。
