动态增强磁共振成像用于肌骨系统肿瘤定性诊断的可行性

目的：探讨动态增强磁共振成像（dynamic contrast enhanced magnetic resonance imaging，DCE-MRI）的药代动力学参数［如容量转移常数（volume transfer constant，Ktrans）、血管外细胞外容积分数（extravascular extracellular space distribute volume per unit tissue volume, Ve）和返流速率常数（microvascular permeability reflux constant，Kep）］用于肌骨系统肿瘤定性诊断中的可行性。方法： 选择2013年10月至2014年9月来北京积水潭医院就诊的肌骨系统肿瘤患者共34例进行回顾性分析，患者使用1.5T MR扫描仪进行检查，DCE MRI使用脂肪抑制3D VIBE(volumetric interpolated breath-hold exam)序列。根据病理诊断结果，将肿瘤分为良性、交界性及恶性，病灶所在层面的正常肌肉组织作为对照组，对每组肿瘤与对照组的Ktrans、Ve和Kep的差异进行配对t检验，对3组病变数据中的差异进行单因素方差分析，P＜0.05认为差异具有统计学意义。结果： 良性肿瘤Ktrans和Kep值与对照组的差异无统计学意义，而Ve值与对照组比较有所升高。交界性肿瘤的Ktrans和Ve值明显高于对照组，而Kep与对照组差异无统计学意义(P>0.05)。恶性肿瘤的Ktrans、Kep和Ve值明显高于对照组。恶性肿瘤的Ktrans (P<0.001)和Kep (P<0.01)均高于良性和交界性肿瘤，Ve高于良性肿瘤(P<0.05)，而与交界性肿瘤差异无统计学意义(P>0.05)。良性和交界性肿瘤的Ktrans、Kep和Ve值之间的差异无统计学意义(P>0.05)。结论： DCE MRI药代动力学参数Ktrans和Kep可以反映肌骨系统良性、交界性和恶性肿瘤在毛细血管渗透性方面存在的差异，这将有助于肿瘤的定性诊断。

Feasibility study of dynamic contrast enhanced magnetic resonance imaging qualita-tive diagnosis of musculoskeletal tumors

Objective:To investigate the feasibility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI)parameters in differentiating musculoskeletal tumors with different behaviours of pathological findings before therapy.Methods:A total of 34 subjects of musculoskeletal tumors were in-volved in this retrospective analysis.DCE-MRI was performed using a fat-saturated 3 D VIBE (volumetric interpolated breath-hold exam)imaging sequence with following parameters:FA,10 degree;TR/TE, 5.6/2.4 ms;slice thickness,4.0 mm with no intersection gap;field of view,310 mm ×213 mm;ma-trix,256 ×178;voxel size,1 .2 mm ×1 .2 mm ×4.0 mm;parallel imaging acceleration factor.The ac-tuation time for the DCE-MRI sequence was 255 s with a temporal resolution of 5 s and 40 image vo-lumes.Using pathological results as a gold standard,tumors were divided into benign,borderline and malignant tumors.Toft’s model was used for calculation of Ktrans (volume transfer constant),Ve (extra-vascular extracellular space distribute volume per unit tissue volume)and Kep(microvascular permeability reflux constant).Those parameters were compared between the lesions and the control tissues using paired t-tests.The one-way analysis of variance was used to assess the difference among benign,border-line and malignant tumors.P values <0.05 difference was statistically significant.Results:Based on the WHO Classification of Tumours of Soft Tissue and Bone(2012)criteria,34 patients were divided into three groups:1 1 for benign tumors,12 for borderline tumors,and 1 1 for malignancies.Compared with control tissues,Ktrans and Kepshowed no difference,but Ve was increased in benign tumors,Kep showed no diffe-rence,butKtransandVewereincreasedinborderlinetumors, Ktrans,KepandVewereincreasedin malignant tumors.Ktrans(P<0.001 )and Kep (P<0.01 )were significantly higher in malignant tumors than in benign and borderline tumors,but did not show any difference between benign tumors and border-line tumors.Ve was significantly higher in malignant tumors than in benign (P<0.05),but did not show any difference between malignant and borderline tumors,benign tumors and borderline tumors (P >0.05 ).Conclusion:DCE-MRI technique is useful to evaluate the pathological behaviour of musculoske-letal tumors.The quantitative analysis of DCE parameters in conjunction with conventional MR images can improve the accuracy of musculoskeletal tumor qualitative analysis.