Characterization of Brain Lesions by Magnetic Resonance Spectroscopy MRS

Abstract

The study was retrospective conducted at Almoalem medical city hospital ,Royal car international hospital, , Khartoum- Sudan during the period from the 2017—2020. The study aims to characterized the different of brain lesions using single-voxel Proton Magnetic Resonance Spectroscopy (MRS). The main problem of the study that the diagnosis of brain lesions was more complicated and histopathology for it was very difficult so that MRS can lead to proper diagnosis and decrease using of histopathology. The study population were 200 patients and was collected from the record system (PACS) of MRI department of Almoalem Medical Center (A) 100 patient’s male and female at any age, male 54. female 46 using semines MRI machine 1.5 Tesla and 100 patient in Royal care international hospital (B), male 54 female46 using Toshiba Excelart Vantage 1.5 Tesla MRI machine, all patient In both hospitals do MRI brain for the patients by lies supine on the examination couch with their head within the head coil, the head is adjusted so that the inter papillary line is parallel to the couch , then applied the MR protocols (T1, T2, diffusion and flair). T1weighted image after intravenous gadolinium administration were obtained at least 2 planes After MRI image done, then MRS is done, using selective metabolites Cho , Cr, NAA ,Lipid/Lac , Cho/Cr and NAA/Cr ratio in Different Brain Lesion. The metabolite ratios were assessed and compared to different lesions using independent sample t-test and ANOVA tests ,in group A total of 100 patients (54 males and 46 females; mean age was 43.75 years) were examined. The most prevalent brain lesions were glioblastoma multiform (GBM) and glioma (24% and 22%). The Cho/Cr ratio was higher in GBM and lymphoma than other brain lesions (4.37 and 4.25 respectively). The NAA/Cr ratio is lower in lymphoma, tuberculoma, inflammation, and abscess (0.6, 1.2, 1.4, and 1.85). The Cho/Cr ratio was significantly higher in neoplastic brain lesions than non neoplastic one (3.95 vs. 1.74, p-value < 0.001). The non neoplastic brain lesions had significantly lower peaks of Cho/Cr than neoplastic lesions which have higher peak. GBM and lymphoma have the highest Cho/Cr ratio compared to other brain lesions but not-significant difference in NAA/Cr ratio (p >0.05) , for neoplastic Cho/Cr ratio is very high while NAA/Cr is low compare to none neoplastic lesion. NAA is reduced in 93%and absent in 7% of cases , 45% of the lesion causes moderate elevation of lipid lactate, 31% mild elevation while in 21 % the lipid lactate is normal and in 3% there is normal lipid lactate and alanine peak seen in cases of meningioma.Total of 100 patients (54 male and 46 females at any age) were examined. After the data collection from PACS of Royal care hospital (group B), metabolites describe is Cho ,Cr, NAA ,Lipid/Lac , Cho/Cr ratio data was then analyzed using statistical package for social sciences version 23, frequency and percentage used for categorical variable, cross tabulation using Chi square test to correlate between study variables,. The study found that the most frequent location of brain lesion in MRI is cerebrum 59%. The most common brain lesion described by MRS are low grade glioma is 18%, high grade glioma is 12%, gliomatosis cerebri 5%, focal encephalitis 3%, TB granuloma 4%. The Cho/Cr is done and show that the minimum ratio 1.10 in non-neoplastic Lesion, maximum ratio 8 in high grade tumor. Most (86%) of these brain lesions yield low NAA. The lipid/lactate may be moderate or mildly elevated In 33% of cases, respectively. Significant correlation found between lesion types suggesting on MRS and metabolites values (p <0.01) as lipid lactate producing sky high peak on different types of non-neoplastic eg. Granuloma, normal peak in all cases of meningioma. The study concluded that MRS complementary to MRI in characterization of brain lesions, it can assess the lesion type and helping in grading of brain tumors. The study recommended that doing MRS routinely in patients with brain lesions to Improve the accuracy of neuro diagnosis and for other benefit in patient management such as, differentiation between tumor and tumor like lesions, encouraging more studies to be done in MRS with a Larger sample size and comparison with other imaging and histopathology Findings, which is the small lesion need Magnetic resonance spectroscopic imaging (MRSI) rather than Single- voxel spectroscopy (SVS) Because of the large voxel size limitations and the length of time of image acquisition, MRS is needed to characterizing the lesion types and put the program of treatment before surgery, so that needs to increase diagnostic centers of MRS in Sudan.