Objective To explore the sensibility of radiation-induced normal brain injury in different regions at acute stage after all cranial radiotherapy by MR diffusion tensor imaging (DTI).Methods A total of 44 patients with brain tumors undergoing whole cranial radiotherapy were examined with convention and enhancement magnetic resonance imaging and diffusion tensor imaging before and three weeks after radiotherapy.The apparent diffusion coefficient ( ADC ),fractional anisotropy ( FA),relative anisotropy (RA) and volume ratio(VR) of DTI in contralateral brain hemisphere after radiotherapy with the dose of 27 Gy were measured and analyzed in different regions.Results No abnormal signal intensities were revealed in convention and enhancement MRI.ADC values in superficial cerebral convolution gray matter,ADC and VR values in deep gray nucleus were increased(t =- 3.321,- 2.810,P ＜ 0.05 ),while FA and RA values in deep gray nucleus were descended( t =2.906,2.349,P ＜0.05 ).There was no statistically significant difference among DTI index in other regions.Conclusions The brain gray matter more sensitive to radiation-induced brain injury in than white matter at acute stage of radiation.DTI could be used to evaluate the functional changes at the histocytology level of radiation-induced brain injury,and to explain the early clinical reactions after radiotherapy.

Objective To explore the value of multiple-mouse MRI in evaluating the therapeutic effect of endostatin for transplantation tumor models of colorectal carcinoma in mice.Methods 24 subcutaneously transplantation tumor’s models of colorectal carcinoma (CT-26) in mice were established, 1 week later, 16 tumor-bearing mice were sieved out and divided randomly into two groups: endostatin (ES) group and normal saline (NS) group, treated with intraperitoneal injection of endostatin 6 mg/kg?d 0.2 ml and equal volume of saline respectively for 14 days. Subsequently, MMMRI was performed, and then the mice were killed immediately and the tumors were cut into sections which were stained with hematoxylin and eosin (H&E). Results Subcutaneous fat layer in NS group presented thinner or disappeared on T1WI,while subcutaneous fat layer in ES group presented thicker. The tumors presented inhomogeneous high signal and intratumoral stippled necrosis on T2WI. The tumor’s volumes measured by MRI and pathology were(2723.26?1136.91) mm3 and (3505.76?1350.12) mm3 respectively,there was no difference between these two measures. And there was correlation between MRI results and pathological results. There was no difference of absolute signal intensity between ES group and NS group on T1WI and T2WI. The signal intensity ratio of ES group (3.19?0.28) was higher than which of NS group (2.60?0.47) on T2WI, and there was no difference on T1WI. Conclusion The therapeutic effect for endostatin on transplantation tumor models of colorectal carcinoma in mice can be displayed distinctly in MMMR image, and the inhibition rate of results can be displayed exactly and noninvasively.