肌肉损伤磁共振成像的病理基础研究

目的：探讨肌肉损伤后磁共振成像（ＭＲＩ）的信号变化与病理改变之间的关系。方法采用１４只灰兔建立肌肉损伤的动物模型，损伤后即刻、１、３、５、７、１０、１４、１８、２２、２６、３２、３８、４４天分别行ＭＲＩ检查，损伤后即刻、１、３、５、７、１４、２１、３５天分别处死１只兔子并进行光镜和电镜。结果ＭＲＩ表现，肌肉损伤后即刻加权像（Ｔ１ＷＩ）表现为大片境界模糊稍高信号影响，７天信号强度达到高峰，但境界清楚

Experimental Study of Relationship between Pathological Changes and MRI of Muscle Injury

Objective To explore the relation between the signal changes of image of MRI and pathological changes from posttraumatic muscles. Methods Muscle injury models on 14 rabbits were set up and immediately i maged with MRI and then repeated on 1st, 3rd, 5th, 7th, 10th, 14th, 18th, 22nd, 26th, 32nd, 38th, 44th days after trauma. Randomly selected eight rabbits were s acrificed to obtain the samples of injured muscle tissue for light microscopic a nd electron microscopic immediately studies and then on 1st, 3rd, 5th, 7th, 14th , 21st, 35th days respectively. Results The injured muscle immediatel y showed patchy high signal on T1WI. The margin of signal was blurred. It became higher and well demarcated on the 7th day. The high signal slowly dropped and k ept high more than 40 days. On T2WI it showed conspicuous high signal immediatel y but the margin of high signal was obscure. The margin became sharp and the hig h signal got up to the peak on 5th to 7th day. Then the high signal dropped grad ually and approached normal on the 44th day. The pathological changes included h emorrhage, edema, degeneration, muscular necrosis and infiltration of inflammato ry cells. They are more obvious on 3rd day. The ultrastructural changes were mus cular fiber edema, autolysis, mitochondrion enlargement, submyolemma sarcoplasmi c reticulum dilation, myotome obscure, collagen and mitochondrion hyperplasia. T here were variant high electronic density granules among muscular fibers. The ul trastructural changes were utmost distinct on 5th to 7th day and some abnormal changes kept at least 40 days. Conclusion MRI is the best choice for image of muscle injury because of its superior inherent contrast resolution and close correlation with ultrastructural changes, especially in T2WI with fat supp ression.