Lee D H, Simon J H, Szumowski J, Feasby T E, Karlik S J, Fox A J, Pelz D M
Departments of Diagnostic Radiology, University Hospital, University of Western Ontario, London, Canada.
Radiology. 1991 May;179(2):543-6. doi: 10.1148/radiology.179.2.2014308.
A derivative of the Dixon method, chopper fat suppression, was used in the magnetic resonance imaging evaluation of 40 patients: 37 with suspected optic nerve lesions, predominantly optic neuritis, and three with orbital lesions. In patients with optic neuritis, the technique was sensitive, allowing detection of 29 of 34 visual-evoked-response-confirmed lesions on T2-weighted lipid-suppressed images. There were no false-positive studies. Sensitivity for detection of optic neuritis was 89%; specificity, 100%; and accuracy, 86%. The technique was also useful for depicting inflammatory changes in the orbital apex due to fungal abscess and confirming the fatty nature of an extraconal dermoid tumor. A slight increase in noise and mild accentuation of susceptibility effects at interfaces of air, bone, and brain did not degrade images significantly. The chopper-based technique requires only standard imaging time and has usual spin-echo sensitivity. The results are comparable to short-inversion-time inversion-recovery imaging, without the constraints of sequence limitations or artifacts at fat and water interfaces.
一种改良的狄克逊法——斩波脂肪抑制技术，被用于40例患者的磁共振成像评估：其中37例怀疑患有视神经病变，主要是视神经炎，3例患有眼眶病变。在视神经炎患者中，该技术具有较高的敏感性，在T2加权脂肪抑制图像上能够检测出34例经视觉诱发电位确认病变中的29例。没有出现假阳性结果。检测视神经炎的敏感性为89%；特异性为100%；准确性为86%。该技术对于描绘真菌性脓肿导致的眶尖炎性改变以及确认眶锥外皮样囊肿的脂肪性质也很有用。在空气、骨骼和脑的界面处，噪声略有增加，磁化率效应轻度增强，但图像质量并未显著下降。基于斩波的技术仅需要标准的成像时间，并且具有常规自旋回波的敏感性。其结果与短反转时间反转恢复成像相当，不存在序列限制或脂肪与水界面伪影的问题。
