3.0 T MRI与X线平片上分别测量膝关节间隙宽度的对比研究

Comparative Study of the Knee Joint Space Width Measured Between MR and X-ray

目的研究3.0 T MRI各向同性梯度回波序列用于测量正常人及不同程度骨性关节炎(OA)患者关节间隙的可行性。方法选取正常志愿者,轻度OA患者(Kellgren-Lawrence分级1～2级)及重度OA患者(Kellgren-Lawrence分级3～4级)各30例,各30个膝关节,分别采用Philips DR和Siemens 3.0 T MR进行检查。由两名观察者分别在3.0 T MR采用各向同性快速小角度激发成像(FLASH)梯度回波序列三维重组冠状位像上和X线平片上测量膝关节间隙,并采用t检验观察两名观察者间在MRI上的测量差异。然后对三组受试对象的X线与MRI检测结果及在MRI及平片上测得组组间的数据运用t检验分别行统计学差异比较。结果在3.0 T MR各向同性FLASH梯度回波序列三维重组冠状位像上测量正常人膝关节间隙,与在X线平片上测量的关节间隙在两名观察者间可重复性较高;对志愿者组、轻度OA组及重度OA组测得的内外侧胫股关节间隙宽度,在MRI与X线平片之间无统计学差异(志愿者组内侧胫股关节间隙t=0.53,P=0.60,外侧t=0.11,P=0.91;轻度OA组内侧胫股关节间隙t=0.25,P=0.80,外侧t=0.07,P=0.94;重度OA组内侧胫股关节间隙t=0.09,P=0.93,外侧t=0.11,P=0.91);志愿者组与轻度OA组间及轻度OA组与重度OA组间在MRI上测量的内外侧胫股关节间隙宽度有统计学差异(志愿者组与轻度OA组间内侧胫股关节间隙t=2.71,P<0.01,外侧t=2.95,P<0.01;轻度OA组与重度OA组间内侧胫股关节间隙t=3.77,P<0.01,外侧t=1.93,P<0.01)。结论使用MRI可以准确测量正常及不同程度OA患者的关节间隙宽度,MRI测量关节间隙的有效性与平片一致。

Objective To study the feasibility of measuring the joint gap width of the health subjects and OA patients with MR isotropic gradient echo sequence. Methods MR and X-ray images were acquired in 30 knee joints of healthy and 30 knee joints of mild osteoarthritis （ Kellgren Lawrence grade 1 or 2） and 30 knee joints of serve osteoarthritis （ Kellgren Lawrence grade 3 or 4） with Siemens 3.0 T MR and Philips DR. The joint gap width was determined with a validated imag- ine software OsriX using the data sets of coranal MPR FLASH MR imagine or X-ray by two observers respectively. Precision errors of intraohserver were compared using a paired t-test. Systematic differences between groups were tested for statistical significance using a paired t test. Results The data of normal knee joint gap width measured on coronal three dimension- al reconstruction images of isotropic FLASH gradient echo sequence at 3.0T MR had no statistical difference with the joint gap width measured on the X ray film. Both methods had high interobserver reproducibility. No significant differences were found between MR and X ray data set in the three groups（ The width of medial tibiofemoral joint gap of health group t = O. 53, P = 0.60, laterlal t = 0. 11, P = 0.91 ; The width of medial tibiofemoral joint gap of mild OA group t = 0. 25, P = 0.80, latedal t =0. 07 ,P =0.94;The width of medial tibiofemoral joint gap of serve OA group t =0. 09,P =0.93, laterlal t = O. 11, P = 0.91 ）. The width of latedal or medial tibiofemoral joint gap of severe OA group was significantly decreased com- pared with healthy or mild OA group（ The medial tibiofemoral joint gap between health group and mild OA group t = 2. 71, P 〈 0.01 ;laterlal t = 2. 95, P 〈 0.01 ; The medial tibiofemoral joint gap between mild OA group and serve OA group t = 3.77,P 〈 0.01 ; laterlal t = 1.93, P 〈 0.01 ） respectively. Conclusion MR imagine can provide accurate and precise measurement of the joint gap width of the health subjects and OA patients in the knee and can observe the joint gap width as consistent with X-ray.