基于MRI二维影像下股骨髁间窝的三维可视化研究

THREE-DIMENSIONAL VISUALIZATION OF INTERCONDYLAR NOTCH BASED ON MRI TWO-DIMENSIONAL IMAGES

目的通过MRI二维影像对股骨髁间窝进行三维重建及测量,探讨虚拟股骨髁间窝成形术的可行性。方法 2009年9月-12月募集健康志愿者30名,男、女各15名,年龄20～30岁,身高150～185 cm,体重45～74 kg。排除膝关节疾病和手术史。根据性别不同将研究对象分为男性组和女性组,并将同性别的膝关节分为左膝及右膝2个亚组。对30名志愿者行双膝关节MRI扫描,将MRI二维图像导入交互式医学影像控制系统Mimics10.01,并对膝关节进行三维重建,通过三维图像测量获取髁间窝相关解剖学数据:髁间窝宽度(notch width,NW),内、外股骨髁宽度(condylar width,CW),髁间窝指数(notch width index,NWI)。收集2010年1月-3月收治的前交叉韧带(anteriorcruciate ligament,ACL)损伤患者膝关节三维图像,筛选出4例髁间窝狭窄(NWI≤0.2)的患者,在患者膝关节三维图像上虚拟髁间窝成形术,计算截骨厚度,并在ACL重建术中实施,评估移植物与髁间窝的撞击情况。结果男性组与女性组双侧股骨髁间窝三维模型的NW、CW比较差异均有统计学意义(P<0.05),NWI比较差异无统计学意义(P>0.05)。男性组内及女性组内左、右膝股骨髁间窝三维模型的NW、CW、NWI比较差异均无统计学意义(P>0.05)。在ACL重建术中,根据术前测量结果行髁间窝成形术后患者的NWI达正常值(NWI>0.22),韧带重建后关节镜观察以及术后3个月随访时行基于MRI二维图像的数字化三维重建膝关节模型并测量发现重建韧带与髁间窝无撞击。结论计算机三维重建模型与实体的髁间窝形态有较高相似度,NWI可较好地反映髁间窝狭窄程度;计算机虚拟髁间窝成形术可为ACL重建提供术前参考,以避免术后移植物与髁间窝的撞击。

Objective To study the feasibility of virtual intercondylar notchplasty by flapplying MRI two-dimensional（2D） images to reconstruct three-dimensional（3D） images and measure the size of intercondylar notch.Methods Thirty healthy volunteers who had no knee joint disease and surgery history were selected.There were 15 females and 15 males with an age range of 20-30 years,weight range of 45-74 kg,and height range of 150-185 cm.They were divided into male group and female group,and the knees of each group were divided into 2 subgroups（the left group and right group）.MRI scan of the left and right knees was performed,and the 2D images of MRI were imported into Mimics10.01 medical image control system for 3D reconstruction.The related anatomical data as follows were measured from the 3D digital model and analyzed by statistical software： notch width（NW）,condylar width（CW）,and notch width index（NWI）.Then the 3D knee images of patients with anterior cruciate ligament（ACL） injury were collected between January and March 2010,and 4 patients with narrow intercondylar notch（NWI ≤ 0.2） were selected for reconstructing the 3D model of the knee and simulating the intercondylar notch plasty.Then,the volume of osteotomy in 3D model was calculated and flapplied in the ACL reconstruction surgery,and whether the graft had impingement with intercondylar notch or not was evaluated.Results There were signi cant differences in NW and CW between male group and female group（P≤≤0.05）,but no signi cant difference was found in the NWI（P≤≤0.05）.And there was no signi cant difference in NW,CW,and NWI between the left and right knees both in male group and female group（P≤≤0.05）.After ACL reconstruction and intercondylar notchplasty,the shflape of intercondylar notch became normal（NWI≤≤0.22）,no impingement occurred between the graft and intercondylar notch under arthroscopy within 3-month follow-up.Conclusion The shflape of intercondylar notch of 3D model based on MRI 2D images is similar to the real intercondylar notch.NWI is one of important indexes which can reffect the narrow level of intercondylar notch.The virtual intercondylar notchplasty may provide preoperative plan and guidence for ACL reconstruction operation to avoid the impingement between graft and intercondylar notch after surgery.