Abstract: Objective　To provide the anatomical basis for superior sagittal sinus (SSS) meningioma by analyzing the distribution of arachnoid granules (AG) in the superior sagittal sinus and the clinical data of parasagittal meningiomas (PSM).　Methods　Conventional MRI and enhanced MRI data of 100 patients of all ages excluding organic brain lesions were collected, which were named as AG group. The distribution and size of AG in SSS were analyzed . From January 2013 to August 2018, 30 cases of PSM patients information which including the corresponding patients imaging characteristics and origin location in SSS were recorded. This group was named as PSM group.　Results　There were 32 cases which can recognize AG in the superior sagittal sinus of the AG group, including 6 cases of AG in the anterior 1/3 SSS, 24 cases of AG in the middle 1/3 SSS and 11 cases of AG in the posterior 1/3 SSS. There were 5 cases with meningioma in the superior sagittal sinus of the PSM group, including 2 cases in the middle of the superior sagittal sinus and 3 cases in the back of the superior sagittal sinus. All patients were treated by surgery and followed up for 24~33 months, without tumor recurrence. The distribution of AG in the sinuses was similar to that of meningioma in the sinuses, and the imaging morphology of the tumor accorded with the growth rule in the sinuses. Conclusions　Not all PSM originates from the paranasal sinus, only a few of them may originate from the AG in the SSS. Parasagittal meningiomas, which are characterized by roughly symmetrical expansion to both sides, can be defined as “SSS meningiomas”.

Key words: Meningioma, 　Superior sagittal sinus, 　Arachnoid granules, 　Magnetic resonance imaging