Pichest metarugcheep
From the Department of neuroradiology. Prasat neurological institute, bangkok, Thailand.
Background and purpose : DWI and MRS have been used for the differentiation and grading of brain tumors for more than 10 years. We attempted to study the diagnostic efficacy of these two techniques inn MR imaging as correlated to the histopathology.
Methods : Seventy patients with mass like lesions diagnosed by conventional MRI and pathologically or clinically proved (11 low grade astrocytomas and 10 high grade astrocytomas. 7 metastases, 3 lymphomas, 2 germinomas, 1 medulloblastoma and 1 neuroblastoma, as well as 17 meningiomas, 5 schwannomas and 13 non tumors) and 20 normal controls were prospectively evaluated with conventional MRI (Press TR1500 and TE135) and DWI (b=0.500 and 1000 s/ mm2)
Results: Seventy patients were screwed to the inclusion criteria comprising of 40 men and 30 woman, age ranging from 15 to 75 yrs (mean age 45 years). Fifty seven patients (81%) were tumors and thirteen patients (19%) non-tumors. Base on the histopathologic classification, 24/57 (42%) were malignant ( 10 high grade astrocytomas, 7 metastases, 3 lymphomas, 1 medulloblastoma, 1 neuroblastoma and 2 germinomas) and 33/57 (58%) were benign (11 low grade astrocytomas, 17 menigiomas, 5 schwannomas). The 13 non-tumors were cerebral infarct 6, cysticercosis 3, abscess 2 and multiple sclerosis 2. The MRS showed benefit in differentiating tumor from non-tumor, malignant from benign and extraaxial from intraaxial tumor. The most significant parameter were the Cho/Cr value with cut point at 1.3 and the presence of lactate or lipid. Cho/Cr more than 1.3 favored tumor and less than 1.3 favored non-tumor. Malignant tumor showed more-frequent lactate and lipid. The character of Choline mono peak was found only in extraaxial tumor with helped to differentiate from intraaxial tumor. The Alanin was present only in meningioma. The ADC values were not useful in the differ entiating tumor from non-tumors, malignant from benign, or in grading of the tumor, However restricted diffusion with low ADC value was noted in both of the brain abscesses.
Conclusion : MRS showed diagnosis efficacy in differentiating tumor from non-tumor (p<0.5), benign from malignant tumors (P<0.5) and intraaxial tumors. Cho/Cr more than 1.3 was the key value for the differentiation of tumors from non-tumor. The increased frequency in lactate or lipid might be used for differentiation of malignant from benign tumor. The Choline mono peak was the characteristic of extraaxial tumor. The presence of the alanin was the feature of menunioma , ADC values were not effective for grading tumor or differentiating malignant from benign tumor, and tumor from non-tumor, but restricted diffusion (low ADC value) was noticed in brain abscess.
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การประชุมวิชาการกระทรวงสาธารณสุขครั้งที่ 13 ประจำปี 2548
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