耳源性肥厚性硬脑膜炎的临床表现和CT、MRI特点

Clinical manifestations and characteristics of CT and MRI of otogenic hypertrophic cranial pachymeningitis

目的研究耳源性肥厚性硬脑膜炎的临床表现和CT、MRI表现特点,探讨其CT和MRI诊断及鉴别诊断。方法回顾性分析了8例急、慢性化脓性和慢性增生性中耳乳突炎并发肥厚性硬脑膜炎的临床表现和CT、MRI表现。结果耳源性肥厚性硬脑膜炎的主要临床表现包括①中耳乳突炎的症状;②颞骨岩部炎(岩尖炎)的症状;③颅内压增高。CT表现横轴位CT显示病侧的天幕呈高或等密度,明显强化,强化范围可达同侧甚至对侧幕切迹。冠状位平扫和增强CT可显示增厚的天幕。病侧颞枕叶和/或小脑半球有脑水肿,占位效应显著。MRI表现病侧天幕和颅中、后窝硬脑膜广泛增厚,呈长T1、短T2信号,FLAIR序列和DWI均呈低信号,显著强化,冠状位和矢状位显示最好。结论CT和MRI显示中耳乳突炎同侧天幕及颅中、后窝硬脑膜广泛增厚、密度增高、信号异常、显著强化,可诊断为耳源性肥厚性硬脑膜炎。但应与天幕区蛛网膜下腔出血、天幕脑膜瘤、脑膜转移癌和静脉窦血栓形成所致静脉性脑梗死鉴别。

Objective To investigate clinical manifestations, CT and MRI characteristics of otogenic hypertrophic cranial pachymeningitis （HCP） and its CT and MRI diagnosis and differential diagnosis. Methods The clinical, CT and MRI manifestations of 8 cases of hypertrophic cranial pachymeningitis complicated by acute or chronic purulent or chronic proliferative otomastoiditis were analyzed retrospectively. Results Clinical manifestations of the HCP included： ①symptoms of otomastoiditis; ②symptoms of Gradenigo＇s syndrome; ③high intracranial pressure. CT manifestations： axial CT showed that the ipsilateral tentoria cerebelli manifested high density or equal density, enhanced obviously, the extent of enhancement might include ipsilateral incisurae tentorii cerebelli, even contralateral incisurae tentorii cerebelli. CT plain scan and enhanced scan with coronal position could show thickened tentoria cerebelli. Edema appeared in ipsilateral temporal and occipital lobes and/or cerebelli, which had obvious occupying effect. MRI manifestations： the ipsilateral tentoria cerebelli were thickened extensively, manifested long T1 and short T2 signals. In FLAIR sequence and DWI, the thickened tentoria cerebelli showed low signals. The thickened tentoria cerebelli were showed best with coronal and sagittal scans. Adjacent brain edema showed long T1 and long T2 signals, and high signal in FLAIR sequence, equal or slightly high signals in DWI. Enhanced scans showed that the ipsilateral dura maters of middle cranial fossa, posterior cranial fossa and tentorium cerebelli were thickened extensively, enhanced significantly. Conclusion If CT and MRI show that the dura maters of tentorium cerebelli and middle cranial fossa, posterior cranial fossa at the ipsilateral site of otomastoiditis are thickened extensively with high density in CT, abnormal signals in MRI and obvious enhancement, otogenic hypertrophic cranial pachymeningitis should be diagnosed. Differential diagnoses should include subarachnoid hemorrhage in the region of tentorium cerebelli, meningiomas in the region of tentorium cerebelli, metastatic carcinomas of meninges, and venous cerebral infarction.