目的:探讨颅内动脉MR血管壁成像(MR-VWI)的图像质量对基于影像组学特征构建症状性斑块预测模型的影响。方法:回顾性搜集因颅内动脉粥样硬化行MR-VWI检查且因图像质量不佳而即刻重复扫描的病例作为本研究的第一部分。MR-VWI序列包括全脑3...目的:探讨颅内动脉MR血管壁成像(MR-VWI)的图像质量对基于影像组学特征构建症状性斑块预测模型的影响。方法:回顾性搜集因颅内动脉粥样硬化行MR-VWI检查且因图像质量不佳而即刻重复扫描的病例作为本研究的第一部分。MR-VWI序列包括全脑3D SPACE T_(1)WI平扫和增强,目标血管(单侧大脑中动脉或基底动脉)的2D TSE T_(2)WI。拟分析100个常用的影像组学特征,包括形状特征9个,一阶梯度特征18个,纹理特征73个。通过比较重复扫描的斑块影像组学特征,筛选出易受图像质量影响的不稳定特征。回顾性搜集因颅内动脉粥样硬化狭窄行MR-VWI检查的病例作为本研究的第二部分。首先,基于全部病例的斑块影像组学特征构建症状性斑块的预测模型(模型A);其次,剔除所有不稳定特征后构建预测模型(模型B);最后,剔除图像质量不佳者,构建预测模型(模型C)。重复扫描影像组学特征的比较,采用Wilcoxon符号秩和检验。预测模型的诊断效能采用受试者工作特征曲线(ROC曲线)进行分析,诊断效能高低主要通过曲线下面积(AUC)体现,以DeLong检验比较不同模型效能的差异。结果:第一部分纳入24例患者,发现3D SPACE T_(1)WI序列的形状特征和一阶梯度特征均无不稳定特征,纹理特征中的不稳定特征仅占1/73。3D SPACE T_(1)WI增强序列的形状特征、一阶梯度特征以及纹理特征中的不稳定特征占比分别是3/9、2/18和17/73。2D TSE T_(2)WI序列的形状特征、一阶梯度特征以及纹理特征中的不稳定特征占比分别是2/9、2/18和19/73。第二部分,102例患者的120个斑块纳入分析,其中症状性斑块51个,无症状斑块69个。模型A的AUC为0.708±0.022;与第一部的不稳定特征比对,模型A筛选出的8个影像组学特征中有3个不稳定特征。模型B的AUC为0.740±0.007。模型C预测颅内症状性斑块的预测效能最好,AUC为0.758±0.013;与第一部分的不稳定特征比对,模型C的8个影像组学特征均为稳定特征。结论:基于MR-VWI影像组学构建颅内症状性斑块的预测模型时,图像质量的优劣对斑块影像组学特征的有一定影响,图像质量越好则预测效能越高。展开更多
Background There is a strong need for quick noninvasive diagnostic technique that can give a valid estimate of the status of the cartilage reliably, discriminating intact cartilage from various grades of impaired cart...Background There is a strong need for quick noninvasive diagnostic technique that can give a valid estimate of the status of the cartilage reliably, discriminating intact cartilage from various grades of impaired cartilage. The goal of this study was to assess the incidence of knee cartilage injuries and compare the accuracy of two-dimension spin echo （2D SE） and fast spin echo （FSE） （conventional MRI）, three-dimensional spoiled gradient echo （3D SPGR）, three-dimensional fast imaging employing steady state acquisition （3D FIESTA） MR imaging sequences with surgical examination of the articular cartilage. Methods One hundred and thirty-eight knees with history of knee trauma received conventional MRI, 3D SPGR and 3D FIESTA MRI examination before surgery, and surgical examination of articular cartilage was used as reference standard. A modified version of the Noyes classification system was applied for the evaluation of the lateral femoral condyle （LFC）, medial femoral condyle （MFC）, lateral tibial plateau （LTP）, medial tibial plateau （MTP）, trochlea and patella. The incidence and distributions of different injured grades at different articular surfaces of knee were assessed. A series of assessment indeces of 3D SPGR, 3D FIESTA, and the combination of the conventional MRI and 3D SPGR imaging were calculated. Results The incidence of cartilage defects （grade 2 to 4） was 22% （183/828）, according to surgical examination. Grade 3 and 4 lesions were absent at the medial tibial plateau. The rates of exact match between the grading results of different MRI procedures and surgical examination were 49% of 3D SPGR, 61% of 3D FIESTA, and 82% of the combination of 3D SPGR and conventional MRI. Also, the combination of 3D SPGR and conventional MR imaging provided the highest sensitivity, specificity, accuracy, positive and negative predictive values, at 71%, 97%, 90%, 90% and 90%, respectively. Conclusions For all the articular surfaces of the traumatic knees, about one fifth （22%） were cartilage defects. Both 3D SPGR and 3D FIESTA imaging performed similarly in detecting cartilage lesions of the knee. The increased accuracy in chondral assessment can be achieved by combining 3D SPGR and conventional MRI within a reasonable time.展开更多
Background It is of value to identify the non-invasive means that can accurately reflect the blood supply of epiphysis and is more sensitive in detection of early ischemia of epiphysis than the conventional gadoterid...Background It is of value to identify the non-invasive means that can accurately reflect the blood supply of epiphysis and is more sensitive in detection of early ischemia of epiphysis than the conventional gadoteridol （Gd）-enhanced SE TlWI. The aim of this study was to evaluate the blood supply of various anatomic regions at the end of normal growing long bone using dynamic Gd-enhanced MR imaging and compare the sensitivities between dynamic Gd-enhanced MR imaging and conventional Gd-enhanced SE TlWl in the detection of decreased blood perfusion of early epiphyseal ischemia. Methods Twenty-seven two-week-old piglets were used in this study. For the study of the end of normal growing long bone, unilateral MR imaging of the distal femur and proximal tibia was performed on eleven piglets. The comparison was made among various anatomic regions （physeal and epiphyseal cartilage, metaphyseal spongiosa, the secondary ossification center and metaphysis） using MRI in terms of the enhancement ratio and speed. Their relationships with the histological findings, including RBC/mm^2 and vessel distribution, were evaluated. To examine ischemic femoral head, 16 piglets were divided into two groups, with the control group having 8 piglets （involving 16 normal hips） and an ischemic group having 8 piglets （involving 16 hips with hyperabduction）. In the ischemic group, MR imaging was performed on the hips in the hyperabduction immobilized persistently for 30 minutes. After MRI, the piglets were allowed to ambulate freely for 1 day and the same MR scanning was then repeated in a neutral position. The difference in enhancement ratio and speed of the femoral head between the control and ischemic group were evaluated. Results With regard to the end of normal growing long bone, the enhancement ratio of the metaphyseal spongiosa was greatest among all the anatomic regions （P 〈0.001）. The enhancement ratio of physeal cartilage was greater than that of epiphyseal cartilage （P 〈0. 001）, which was the lowest in all tissues （P 〈0.001）. The enhancement speed of the spongiosa was greater than that of physis but the difference was not significant （P 〉0.05）. The enhancement speed of physis was greater than that of epiphyseal cartilage （P 〈0.05）, which was the lowest among all the tissues （P 〈0.05）. The enhancement ratio and speed were found to be related to the histological findings, including RBC/mm^2 （R 〉0.75） and distribution of vessels in the tissues. With ischemic femoral head, the enhancement ratios of physis, anterior part and posterior part of capital femoral epiphysis were significantly lower （P 〈0.05） and enhanced more slowly （P 〈0.05） than those of normal femoral head on dynamic Gd-enhanced MR imaging. On conventional Gd-enhanced SE TlWl, however, no apparent decrease in enhancement ratio and speed in ischemic hips was found （P 〈0.05）, when they were compared with those in the normal hips. Conclusions Dynamic gadoteridol-enhanced MR imaging can reveal the blood supply in various anatomic regions of the end of normal growing long bone. It is more sensitive than conventional Gd-enhanced SE TlWl in the detection of early epiphyseal ischemia.展开更多
文摘目的:探讨颅内动脉MR血管壁成像(MR-VWI)的图像质量对基于影像组学特征构建症状性斑块预测模型的影响。方法:回顾性搜集因颅内动脉粥样硬化行MR-VWI检查且因图像质量不佳而即刻重复扫描的病例作为本研究的第一部分。MR-VWI序列包括全脑3D SPACE T_(1)WI平扫和增强,目标血管(单侧大脑中动脉或基底动脉)的2D TSE T_(2)WI。拟分析100个常用的影像组学特征,包括形状特征9个,一阶梯度特征18个,纹理特征73个。通过比较重复扫描的斑块影像组学特征,筛选出易受图像质量影响的不稳定特征。回顾性搜集因颅内动脉粥样硬化狭窄行MR-VWI检查的病例作为本研究的第二部分。首先,基于全部病例的斑块影像组学特征构建症状性斑块的预测模型(模型A);其次,剔除所有不稳定特征后构建预测模型(模型B);最后,剔除图像质量不佳者,构建预测模型(模型C)。重复扫描影像组学特征的比较,采用Wilcoxon符号秩和检验。预测模型的诊断效能采用受试者工作特征曲线(ROC曲线)进行分析,诊断效能高低主要通过曲线下面积(AUC)体现,以DeLong检验比较不同模型效能的差异。结果:第一部分纳入24例患者,发现3D SPACE T_(1)WI序列的形状特征和一阶梯度特征均无不稳定特征,纹理特征中的不稳定特征仅占1/73。3D SPACE T_(1)WI增强序列的形状特征、一阶梯度特征以及纹理特征中的不稳定特征占比分别是3/9、2/18和17/73。2D TSE T_(2)WI序列的形状特征、一阶梯度特征以及纹理特征中的不稳定特征占比分别是2/9、2/18和19/73。第二部分,102例患者的120个斑块纳入分析,其中症状性斑块51个,无症状斑块69个。模型A的AUC为0.708±0.022;与第一部的不稳定特征比对,模型A筛选出的8个影像组学特征中有3个不稳定特征。模型B的AUC为0.740±0.007。模型C预测颅内症状性斑块的预测效能最好,AUC为0.758±0.013;与第一部分的不稳定特征比对,模型C的8个影像组学特征均为稳定特征。结论:基于MR-VWI影像组学构建颅内症状性斑块的预测模型时,图像质量的优劣对斑块影像组学特征的有一定影响,图像质量越好则预测效能越高。
基金This research was supported by the National Natural Science Foundation of China （No. 30670605 and No. 30870701）.
文摘Background There is a strong need for quick noninvasive diagnostic technique that can give a valid estimate of the status of the cartilage reliably, discriminating intact cartilage from various grades of impaired cartilage. The goal of this study was to assess the incidence of knee cartilage injuries and compare the accuracy of two-dimension spin echo （2D SE） and fast spin echo （FSE） （conventional MRI）, three-dimensional spoiled gradient echo （3D SPGR）, three-dimensional fast imaging employing steady state acquisition （3D FIESTA） MR imaging sequences with surgical examination of the articular cartilage. Methods One hundred and thirty-eight knees with history of knee trauma received conventional MRI, 3D SPGR and 3D FIESTA MRI examination before surgery, and surgical examination of articular cartilage was used as reference standard. A modified version of the Noyes classification system was applied for the evaluation of the lateral femoral condyle （LFC）, medial femoral condyle （MFC）, lateral tibial plateau （LTP）, medial tibial plateau （MTP）, trochlea and patella. The incidence and distributions of different injured grades at different articular surfaces of knee were assessed. A series of assessment indeces of 3D SPGR, 3D FIESTA, and the combination of the conventional MRI and 3D SPGR imaging were calculated. Results The incidence of cartilage defects （grade 2 to 4） was 22% （183/828）, according to surgical examination. Grade 3 and 4 lesions were absent at the medial tibial plateau. The rates of exact match between the grading results of different MRI procedures and surgical examination were 49% of 3D SPGR, 61% of 3D FIESTA, and 82% of the combination of 3D SPGR and conventional MRI. Also, the combination of 3D SPGR and conventional MR imaging provided the highest sensitivity, specificity, accuracy, positive and negative predictive values, at 71%, 97%, 90%, 90% and 90%, respectively. Conclusions For all the articular surfaces of the traumatic knees, about one fifth （22%） were cartilage defects. Both 3D SPGR and 3D FIESTA imaging performed similarly in detecting cartilage lesions of the knee. The increased accuracy in chondral assessment can be achieved by combining 3D SPGR and conventional MRI within a reasonable time.
文摘Background It is of value to identify the non-invasive means that can accurately reflect the blood supply of epiphysis and is more sensitive in detection of early ischemia of epiphysis than the conventional gadoteridol （Gd）-enhanced SE TlWI. The aim of this study was to evaluate the blood supply of various anatomic regions at the end of normal growing long bone using dynamic Gd-enhanced MR imaging and compare the sensitivities between dynamic Gd-enhanced MR imaging and conventional Gd-enhanced SE TlWl in the detection of decreased blood perfusion of early epiphyseal ischemia. Methods Twenty-seven two-week-old piglets were used in this study. For the study of the end of normal growing long bone, unilateral MR imaging of the distal femur and proximal tibia was performed on eleven piglets. The comparison was made among various anatomic regions （physeal and epiphyseal cartilage, metaphyseal spongiosa, the secondary ossification center and metaphysis） using MRI in terms of the enhancement ratio and speed. Their relationships with the histological findings, including RBC/mm^2 and vessel distribution, were evaluated. To examine ischemic femoral head, 16 piglets were divided into two groups, with the control group having 8 piglets （involving 16 normal hips） and an ischemic group having 8 piglets （involving 16 hips with hyperabduction）. In the ischemic group, MR imaging was performed on the hips in the hyperabduction immobilized persistently for 30 minutes. After MRI, the piglets were allowed to ambulate freely for 1 day and the same MR scanning was then repeated in a neutral position. The difference in enhancement ratio and speed of the femoral head between the control and ischemic group were evaluated. Results With regard to the end of normal growing long bone, the enhancement ratio of the metaphyseal spongiosa was greatest among all the anatomic regions （P 〈0.001）. The enhancement ratio of physeal cartilage was greater than that of epiphyseal cartilage （P 〈0. 001）, which was the lowest in all tissues （P 〈0.001）. The enhancement speed of the spongiosa was greater than that of physis but the difference was not significant （P 〉0.05）. The enhancement speed of physis was greater than that of epiphyseal cartilage （P 〈0.05）, which was the lowest among all the tissues （P 〈0.05）. The enhancement ratio and speed were found to be related to the histological findings, including RBC/mm^2 （R 〉0.75） and distribution of vessels in the tissues. With ischemic femoral head, the enhancement ratios of physis, anterior part and posterior part of capital femoral epiphysis were significantly lower （P 〈0.05） and enhanced more slowly （P 〈0.05） than those of normal femoral head on dynamic Gd-enhanced MR imaging. On conventional Gd-enhanced SE TlWl, however, no apparent decrease in enhancement ratio and speed in ischemic hips was found （P 〈0.05）, when they were compared with those in the normal hips. Conclusions Dynamic gadoteridol-enhanced MR imaging can reveal the blood supply in various anatomic regions of the end of normal growing long bone. It is more sensitive than conventional Gd-enhanced SE TlWl in the detection of early epiphyseal ischemia.
