40例鞍区囊性病变的MRI鉴别诊断分析

MRI Features and Differential Diagnosis of Sellar Cystic Lesions

目的分析囊性垂体瘤、囊性颅咽管瘤及Rathke囊肿的MRI表现,提高鞍区常见囊性病变的MRI诊断水平。资料与方法搜集40例经手术及病理证实的鞍区囊性病变患者的临床和影像资料,其中囊性垂体瘤12例,囊性颅咽管瘤13例,Rathke囊肿15例。全部病例均行MRI平扫和增强扫描。分析囊性病灶的位置、大小、囊壁厚度以及"束腰征"、海绵窦包绕等特殊征象。应用SPSS 11.0软件包,采用卡方检验对病灶的大小及囊壁的厚度进行统计学分析。结果病灶位于鞍上者仅见于囊性颅咽管瘤,鞍内且位于垂体前后叶之间仅见于Rathke囊肿。三者囊的大小和囊壁厚度差异均有统计学意义(χ2=17.65,P=0.0001;χ2=6.26,P=0.04)。无壁或薄壁者多见于颅咽管瘤和Rathke囊肿,占40%(10/25),厚壁者多见于囊性垂体瘤,占53%(8/15)。病灶直径≥2 cm多见于颅咽管瘤,占63%(12/19),<2 cm多见于Rathke囊肿,占61%(13/21)。颅咽管瘤和Rathke囊肿信号较复杂,而囊性垂体瘤除1例T1WI等信号,T2WI低信号外,其余11例均为T1WI低信号,T2WI高信号。"束腰征"主要见于囊性垂体瘤(6/7例),亦可见于Rathke囊肿(1/7例)。海绵窦包绕仅出现于囊性垂体瘤。壁结节可见于颅咽管瘤和Rathke囊肿(各2例),颅咽管瘤壁结节增强扫描明显强化,Rathke囊肿未见强化。结论根据囊性病灶的位置、形态、囊内MRI信号以及特殊征象,可对上述3种囊性病变进行鉴别。

Objective To analyze the MRI features of cystic pituitary adenomas,craniopharyngioma and rathke cleft cysts,and to improve the diagnose of sellar cystic lesions.Materials and Methods The clinical and imaging data of 40 sellar cystic lesions including cystic pituitary adenomas（n=12）,craniopharyngioma（n=13）,and rathke cleft cysts（n=15） were collected and analyzed.All cases were performed MRI plain and enhanced scanning.The location,size,thickness of wall and some special signs such as ＂waist sign＂,cavernous sinus surrounding were analyzed.The lesion size and wall thickness were statistically analyzed with SPSS 11.0 software package,using the chi-square test.Results Lesions situated on suprasellar found only in craniopharyngioma.Located between anterior and posterior of pituitary found only in rathke cyst.There were significant statistic differences of the size and wall thickness among three kinds of lesions（χ2= 17.65,P= 0.0001;χ2= 6.26,P= 0.04）.No or thin wall were more common in craniopharyngioma and rathke cyst（40%,10/25）,thick wall were common in cystic pituitary tumor（61%,13/21）,the diameter greater or equal to 2cm were common in craniopharyngioma（71%,12/17）,less than 2cm common in rathke cyst.The signal of rathke cyst and craniopharyngioma performed complex,except one cystic pituitary adenomas showed isointense on T1WI,hypointense on T2WI signal,the remaining 11 cystic pituitary adenomas showed hypointense on T1WI and hyperintense T2WI.＂Waist sign＂ was not only appeared in cystic pituitary adenomas（6/7） but also in rathke cleft cysts（1/7）,cavernous sinus surrounding only appeared in cystic pituitary adenomas.There were 2 cases of craniopharyngioma had mural nodules,enhanced significantly,while 2 cases of rathks cyst showed wall nodules,without significant enhancement.Conclusion According to the location,shape,MRI signal,and special signs,the three cystic lesions can be identified on MR imagings.