Comparison between supine MRI and standing X-ray in the measurement of Cobb angle, thoracic kyphosis and lumbar lordosis in adolescent idiopathic scoliosis
Shi Benlong*, Lam Tsz-ping, Mao Saihu, Liu Zhen, Sun Xu, Cheng Jack CY, Qiu Yong, Zhu Zezhang.
*Department of Spine Surgery, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008, China
Abstract：Objective To study the difference and correlation between supine MR total spine imaging and standing whole-spine X-ray in the measurement of Cobb angle, thoracic kyphosis (TK) and lumbar lordosis (LL) in adolescent idiopathic scoliosis (AIS) patients.Methods A total of 120 AIS patients between 2008 and 2016 with both supine MRI and standing X-ray were retrospectively reviewed. From the standing X-rays, the Cobb angles of main curve, TK and LL were measured. On supine MRI, the coronal Cobb angles, TK and LL were also measured at the same levels accordingly. The comparison between 2 groups was analyzed with paired t test and the correlation was studied using linear regression analysis.Results The average Cobb angles measured on standing X-ray and supine MRI were 33.8°±20.1° and 24.9°±18.3°, respectively (P<0.01). The TK were 15.2°±9.7° and 10.5°±7.7° for X-ray and MRI(P<0.01), while the LL averaged 43.6°±13.8° and 37.1°±13.5° for X-ray and MRI(P<0.01), respectively. The standing X-ray was significantly linearly correlated with supine MRI in terms of Cobb angles, TK and LL with the r values were 0.920,0.706 and 0.565, respectively (P<0.01). The linear regression equations were as follows: ＾YCobb angle on standing X-ray=0.901×XCobb angle on supine MRI+12.517, ＾YTK on standing X-ray=1.055×XTK on supine MRI+3.865, ＾YLL on standing X-ray=0.718×XLL on supine MRI+17.135.Conclusions The coronal Cobb angle, TK and LL measured on supine MRI are significantly linearly correlated with the Cobb angles measured on standing X-ray in AIS patients. Therefore, the supine MRI could serve as a reliable alternative to standing X-ray in the assessment of coronal Cobb angle, TK and LL using the calculated equations.
史本龙, 林子平, 毛赛虎, 刘臻, 孙旭, 郑振耀, 邱勇, 朱泽章. 青少年特发性脊柱侧凸主弯侧凸Cobb角、胸椎后凸角及腰椎前凸角仰卧位MRI与站立位X线测量的对比研究[J]. 中华解剖与临床杂志, 2017, 22(1): 6-10.
Shi Benlong, Lam Tsz-ping, Mao Saihu, Liu Zhen, Sun Xu, Cheng Jack CY, Qiu Yong, Zhu Zezhang.. Comparison between supine MRI and standing X-ray in the measurement of Cobb angle, thoracic kyphosis and lumbar lordosis in adolescent idiopathic scoliosis. Chinese Journal of Anatomy and Clinics, 2017, 22(1): 6-10.
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2017, Vol. 22 
