Here,we report a new method using combined magnetic resonance(MR)-Photoacoustic(PA)-Thermoacoustic(TA)imaging techmiques,and demonstrate its unique ability for in vrivo cancer detection using tumor-bearing mice.Circular scanning TA and PA imaging systems were used to recover the dielectric and optical property dist ributions of three colon carcinoma bearing mice While a 7.0-T magnetic resonance imaging(MRI)unit with a mouse body volume coil was utilized for high resolution structural imaging of the same mice.Three plastic tubes flled with soybean sauce were used as fiducial markers for the co-registration of MR,PA and TA images.The resulting fused images provided both enhanced tumor margin and contrast relative to the surrounding normal tissues.In particular,some finger-like protrusions extending into the surrounding tissues were revealed in the MR/TA infused images.These results show that the tissue functional optical and dielectric properties provided by PA and TA images along with the anatomical structure by MRI in one picture make accurate tumor identification easier.This combined MR-PA-TA-imaging strategy has the potential to offer a dinically useful triple-modality tool for accurate cancer detection and for intraoper ative surgical navigation.
目的采用7.0 T MR扩散张量成像(DT-MRI)技术从心肌纤维水分子扩散、心肌纤维微结构及心肌力学单元角度综合定量研究心肌肥厚模型大鼠的心肌纤维特性。材料与方法 20只健康雄性SD大鼠随机分为正常组(n=10)与心肌肥厚组(n=10),正常组大鼠离体心脏并固定,心肌肥厚组大鼠行胸主动脉缩窄手术12周后离体心脏并固定,采用扩散张量成像技术获取图像,并使用Diffusion Toolkit、Trackvis及Matlab软件进行图像后处理。观察两组大鼠心脏三维整体观、乳头肌层面心肌纤维和张量图以及心肌组织HE染色的特点,使用独立样本t检验统计分析两组大鼠左心室心肌纤维平均ADC值、FA值及螺旋角的差异。结果心脏三维整体观显示,两组大鼠心肌纤维由心外膜向心内膜均呈致密、规则的螺旋排布。乳头肌层面心肌纤维示踪图以及张量图显示正常组心肌纤维走行规则、排布均匀,心肌肥厚组左心室壁较正常组增厚,像素内的张量显示较正常组增加,心外膜向心内膜过渡的三层结构较正常组更明显;心肌肥厚组大鼠较正常组大鼠左心室心肌纤维平均ADC值下降(P<0.01),FA值上升(P<0.05),两组间均有统计学差异。心肌肥厚组大鼠左心室由心外膜至心内膜的平均螺旋角透壁范围较正常组增大(P<0.01),两组间均具有统计学差异。结论扩散张量成像及图像后处理技术可三维可视化定量综合评价大鼠心肌肥厚模型心肌纤维特性较正常大鼠的变化,为将来实现心肌纤维结构、力学、电生理特性的在体研究奠定基础。
