The value of MRI in diagnosis of chordoid meningioma and differenciation with other meningiomas / 实用放射学杂志

ABSTRACT

Objective To analyze the MRI features of chordoid meningioma (CM),and to compare with other meningiomas. Methods Clinical and MRI features of 7 patients with CM confirmed by pathology were analyzed retrospectively.Featrues of every MRI sequence were investigated qualitatively.Meanwhile normalized signal ratios of each sequence were analyzed furtherly,including normalized T1 weighted image intensity ratios (NT1 ),normalized T2 weighted image intensity ratios(NT2 ),normalized ADC ratios (NADC)and normalized T1 WI contast enhancement intensity ratios (NCE).Fisher ’s exact test and Dunnett T 3 test were employed to analyze the difference of CM and nonchordoid meningiomas (34 cases of WHO grade Ⅰ meningioma,1 6 cases of nonchordoid WHO grade Ⅱ meningioma,and 5 case of WHO grade Ⅲ meningioma).Results The CM showed hyperintensity on T2 WI and meanwhile other nonchordoid meningiomas demonstrated isointensity,hypointensity or slight hyperintensity on T2 WI.Evaluations of DWI revealed variable signal intensities of CM.But all 7 cases had no obvious restricted diffusion,and increased signal was seen on the ADC map in each patient.The solid parts of CM enhanced markedly after contrast agent injection.Quantitative indicators NT2 , NADC and NCE of CM were higher than other meningiomas(P <0.01),but NT1 showed no statistic difference between CM and other meningiomas (P =0.889).Whether there was cyst,necrosis,orflow void sign on T2 WI,and no matter with or without perifocal edema,dural tail sign and a broader base among meningiomas had no significance in differentiating CM and other meningiomas.Conclusion CM has typical MRI features.The tumors show hyperintensity on T2 WI,especially have no obvious restricted diffusion and enhance markedly after contrast.The measurement of NT2 ,NADC and NCE enables reliable preoperative prediction of the atypical histopathologic diagnosis.