垂体微腺瘤MRI和CT对照研究

目的：探讨垂体内低信号灶，垂体高度，上缘形状，鞍底骨质凹陷和垂体柄移位对垂体微腺瘤的ＭＲＩ诊断价值；比较ＭＲＩ和ＣＴ在显示上述征像上的能力。材料和方法：对５０例正常对照组垂体腺和４１例病理证实的垂体微腺瘤术前ＭＲＩ进行对比观察，并对其中２０例微腺瘤进行ＭＲＩ和ＣＴ特征对照研究。结果：对照组与腺瘤组相比垂体腺增高，上缘凸起，内有低信号灶的发生率有显著差异（ｐ＜０．０１），鞍底凹陷侵独发生率也有显著差别（ｐ＜０．０５），垂体柄向腺瘤对侧移位发生率无显著差别（ｐ＜０．１）。在判断垂体微腺瘤的位置及大小（５．１±２．０／５．２±１．９ｍｍ）、鞍隔上抬（１６／１５）、垂体柄偏位（１０／９）以及垂体增大（１７／１６）上，ＭＲＩ稍优于ＣＴ（ｐ＞０．２５）。明确鞍底骨质侵蚀ＣＴ明显优于ＭＲＩ（ｐ＜０．０５）。结论：增大垂体腺内出现低信号灶，伴上缘凸起和鞍底凹陷侵蚀为ＭＲＩ诊断微腺瘤最可靠征像；ＭＲＩ在显示上述征像（鞍底骨质侵蚀除外）上优于ＣＴ。

Comparison of MRI and CT Diagnosing Pituitary Microadenoma

Purpose: To investigate MRI diagnostic value of hypointensity, height, shape, infundibular tilting of pituitary gland, and sellar floor erosion in diagnosing pituitary microadenoma; To assess the abilities of MRI and CT in demonstrating the changes above. Materials and methods: The MRI of 50 normal pituitary glands and 41 surgically proven pituitary microadenomas were analyzed and compared. A comparative study of preoperative MRI and CT were also performed on 20 of the 41 tumors. Results: The frequent difference between normals and microadenomas in MRI showing hypointensity in enlarged pituitary gland with convexity of diaphragma sellar, as well as sellar floor erosion was significant (P<0.01 and P<0.05). The infundibular tilting frequent between the two groups was not different (P>0.1). MRI was superior to CT regarding the microadenomas' location and size (5.1 2.0/5.2 1.9), measurement of enlarged gland (19/16), detection of the diaphragma sellae bulge (16/15), and demonstration of infundibular abnormality (10/9). CT was more sensitive than MRI in identifying sellar floor erosion (P<0.05). Conclusion: Hypointensity in enlarged pituitary gland with diaphragma sellae bulge and sellar floor erosion were reliable criteria in diagnosing pituitary microadenoma. MR is more sensitive and accurate than CT in demonstrating those criteria (not including sellar floor erosion) above.