| [Objective] Diffuse astrocytomas are the most common kind of primary brain tumors, and it is always a disturbing problem for radiologists to accurately grade the diffuse astrocytomas and differentiate them from other similar diseases preoperatively. In this study, 35 cases of diffuse astrocytomas and 29 relating diseases which should be differentiated from diffuse astrocytomas were collected. Our purpose is to discuss the values of in vivo proton MR spectroscopy in grading and differential diagnosis of diffuse astrocytomas based on their MR spectroscopy manifestations.[Materials and Methods] 35 cases of diffuse astrocytomas including 8 astrocytomas(WHO grade II), 13 anaplastic astrocytomas(grade III) and 14 glioblastoma multiformes(grade IV). The 29 relating diseases which should be differentiated from diffuse astrocytomas including 7 cases of acute cerebral infarctions, 10 cases of solitary metastases, and 12 cases of meningiomas. All the 35 diffuse astrocyomas and 12 meningiomas were proved pathologically, and among the 10 cases of metastases 5 were proved pathologically, the other 5 were proved clinically. Only precontrast MRI scan(including conventional sagittal and coronal Tl-weighted images, axial T2-weighted images and FLAIR images) were performed in 7 cerebral infarctions and 8 meningiomas. Precontrast MRI scan and postcontrast MRI scan (including sagittal, coronal and axial Tl-weighted images) were performed in the other cases. All the cases underwent single voxel(SV) MRspectroscopy, and 6 diffuse astrocytomas and 4 metastases also underwent MR spectroscopy imaging(SI). The Cho/Cr, NAA/Cr, Lac/Cr ratios of enhanced regions, peritumoral regions, infarction areas, and contralateral normal brain tissues were acquired, student t test and rank sum test(Kruskal-Wallis H method and Mann-Whitney U method) were used to compare the metabolite ratios, P value less than 0.05 was considered significant.[Results] The Cho/Cr of three group diffuse astrocytomas(including astrocytoma, anaplastic astrocytoma, and glioblastoma multiforme) were 2.7088 ±1.2278, 5.8123 ± 2.3743 and 5.2893 ± 1.4623(mean ± SD) respectively. Mann-Whitney U method showed statistically significant differences between astrocytomas and anaplastic astrocytomas, astrocytomas and glioblastoma multiformes for Cho/Cr(.P<0.01), but the difference between anaplastic astrocytomas and glioblastoma multiformes was not significant(P=0.458). The Lac/Cr of three group diffuse astrocytomas were 0.1000 +0.2828 > 1.8792 + 1.5951 and 3.6557?.1953 respectively, the differences among three groups were all significant(P<0.001 for astrocytomas vs anaplastic astrocytomas and astrocytomas vs glioblastoma multiformes, /MJ.025 for anaplastic astrocytomas vs glioblastoma multiformes). No significant differences among three groups for NAA/Cr were found(P=0.679).The Cho/Cr of 7 astrocytomas and 7 acute cerebral infarctions were 2.6857 ±1.3244 and 1.0957 ±0.2451 respectively, student t test showed statistically significant difference(.P=0.019). The Lac/Cr of the two groups were 0.1143?0.3024 and 2.1086 ± 0.7658 respectively, significant difference was also found(P<0.001). The NAA/Cr were 0.8971 ± 0.2528 and 1.2200 ± 0.5496 respectively, the difference was not significant(P=0.194).The Cho/Cr of 25 high grade astrocytomas and 10 metastases were 5.7700 + 1.8212 and 4.4500±2.4250, NAA/Cr were 0.9476±0.5026 and 1.1850 ±0.5637,Lac/Cr were 2.4684±1.7105 and 3.211012.7077 respectively, there were no significant differences for all ratios between the two groups, P>0.05. The Cho/Cr in peritumoral regions of the two groups were 2.3300±1.2100 and 1.0750 ± 0.2541 respectively, statistically significant difference was found , P<0.001, but the NAA/Cr and Lac/Cr of the two groups have no significant differences.The Cho/Cr of 35 diffuse astrocytomas and 12 meningiomas were 4.8937 + 2.1513 and 13.0792±7.4252 respectively, Student t test showed statistically significant difference(P=0.003). and the NAA/Cr were 0.9377±0.4363 and 0.9767 + 0.3609 respec... |
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