| [Background] Cerebral infarction and glioma is common disease in clinic of central nervous system. It has higher mortality and disability if not treated timely and effective. Conventional magnetic resonance imaging (MRI) can make correct diagnosis in typical case based on its characteristic clinical and imaging. But sometimes the clinical cases are not typical. There are similar morphology and signal characteristics between cerebral infarction and glioma because of the evolution of the cerebral infarction in different periods and the diffuse growth characteristics of glioma. Especially in the differential diagnosis between subacute cerebral infarction and low-grade glioma, it is easily to make a misdiagnosis only rely on conventional MRI, and the choice of clinical treatment and prognosis will be effected. In recent years, imaging has not only confined to the morphological level with the continuous development of medical imaging, and functional imaging gradually get more and more clinical application. Magnetic resonance spectroscopy(MRS) is the only non-invasive technology to detect the amount of chemicals in the body and observe the changes of metabolism of living cells, and it has been widely used in clinical.[Objective] To explore the application value of multivoxel 2D 1H-MRS in the differential diagnosis of subacute cerebral infarction and low-grade glioma.[Methods] Conventional MRI and 2D 1H-MRS were performed in 20 cases with subacute cerebral infarction and 22 cases with low-grade glioma. All the patients were examined by computed tomography (CT) to exclude the brain hemorrhage. The onset time of the cerebral infarction patients is chosen from 3 days to 2 weeks. All the cases examined by 2D 1H-MRS after conventional MRI scan, and exclude patients with lesser area of cerebral infarction. The final diagnosis was confirmed by clinical treatment or follow-up. The diagnosis of low-grade glioma was proved by operation and pathology, and excluded the patients with other intracranial tumors or higher levels of brain glioma. Among the 22 patients with low grade gliomas, there are 20 cases examined by 2D 1H-MRS based on MRI scan and enhanced scan and the other 2cases examined by 2D 1H-MRS after MRI scan because the patients refused to MRI enhanced scan. We observed the conventional MRI characteristics of the lesions in patients with subacute cerebral infarction and low grade gliomas. At the same time the variation of Cho、Cr、NAA、Lac and Lip of the lesions would be observed by comparing the contralateral normal brain tissue or close relative. We compute the ratios of Cho/Cr、NAA/Cr and NAA/Cho by using statistical analysis software package and the ratios P＜0.05 were considered to have statistical significance.[Results] On conventional MRI scan, the 20 cases of subacute cerebral infarction was demonstrated as big shape or patchy shape, lower or slightly lower signal on T1WI, higher or slightly higher signal on T2WI, equal or higher signal on DWI. The signals were homogeneous or lack of homogeneous, and the boundaries were clear or fuzzy. In our cases, there were 2 cases with mild to moderate effect and there was no edema around the lesion. Compared with the contralateral or adjacent relatively normal brain tissue,the 2D 1H-MRS images of lesion side showed that the Cho concentration decreased or increased slightly, NAA decreased by varying levels, and Cr irregular changed. At the same time, the ratios Cho/Cr increased or decreased, NAA/Cr and NAA/Cho decreased. There were 12 cases in which varying levels of inverted Lac double-peak appeared. Significantly higher Lip was observed in two patients. The conventional MRI scan sequences of 22 cases of low grade gliomas showed patchy or clumps long T1 and T2 signals、equal or lower signal on DWI. The signals were often inhomogeneous. 9 cases showed varying degrees space effect and the lesions surrounding edema. Contrast-enhanced MRI scan showed mild patchy enhancement, irregular enhancement or no enhancement. The 2D 1H-MRS imaging showed that the concentration of Cho increased, the NAA decreased in varying levels, and the corresponding ratios Cho/Cr increased, NAA/Cr and NAA/Cho decreased. There was no obvious increase of Lac and Lip. The statistical results showed that the differences of Cho/Cr, NAA/Cr, NAA/Cho between subacute cerebral infarction and low grade gliomas have statistically significant with P＜0.05.[Conclusion] The changes of 2D’H-MRS in patients with acute cerebral infarction and low grade gliomas have obvious differences. In the diagnosis and differential diagnosis, it has important clinical value. It can effectively improve the correct rate of cerebral infarction and gliomas, reduce the rate of misdiagnosis. Moreover,2D 1H-MRS examination can be used to analyze the characteristics of the lesions in the level of biochemical metabolism, and provide effective help for the clinical evaluation of the disease. |
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