Role of diffusion tensor imaging in evaluation of prognosis in patients with cervical intraspinal tumors

Abstract

Objective To investigate the change characteristics of diffusion tensor imaging(DTI)parameters value in patients with cervical intraspinal tumor and its relationship with spinal cord function and prognosis. Methods Twenty-two patients with cervical intraspinal tumor(test group)treated with surgical resection in Department of Neurosurgery, Fuzhou General Hospital of Nanjing Military Command, Fuzhou Clinical Medicine School of the Second Military Medical University between February 2014 and January 2015 were selected. Cervical spinal cord MRI conventional sequences and DTI scans were performed at 3 days before procedure and 1 month after procedure respectively. At the same time, 22 healthy subjects were selected as healthy control(HC)group. The values of fractional anisotropy(FA)and apparent diffusion coefficient(ADC)of each cervical spinal cord level were measured in both groups. The whole cervical spinal cord was divided into 3 areas, the tumor head area, tumor area, and tumor tail area, and the FA and ADC values of the 3 areas were calculated. Differences of FA and ADC between two groups and their relationship with McCormick grading were compared and analyzed. Results The FA values of the 3 areas of cervical spinal cord of the test group were significantly lower than those of the HC group(all P<0.05), and the ADC values were significantly higher than those of the HC group(all P<0.05). There were significant differences in FA and ADC values among each area in test group(all P<0.05). The FA values in the tumor area and tumor head area at 1 month after procedure were increased significantly compared with those before procedure(all P<0.05). The improvement rate of spinal cord function in the group of increased FA value in tumor head area after procedure was significantly higher than that of the decreased group(P<0.05). The sensitivity of the change of postoperative FA values for predicting spinal cord function and prognosis in tumor head area was 88%. Conclusions The DTI index of cervical cord in patients with cervical intraspinal tumor may change significantly in the whole range of the cervical spinal cord. These changes after procedure may show different degrees of recovery in the different regions of cervical spinal cord, and it is associated with the improvement of cervical spinal cord function. The change of FA value in tumor head area after procedure is a rather sensitive predictor for spinal cord function and prognosis. Key words: Spinal cord neoplasms; Diffusion tensor imaging; Fractional anisotropy; Apparent diffusion coefficient