Two pediatric cases of epidural hematoma in the posterior fossa with extension along the sigmoid sinus groove: MR evaluation.

To discuss the computed tomography (CT) and magnetic resonance (MR) findings of posterior fossa epidural hematoma (PFEDH) mimicking sinus thrombosis, we present two pediatric cases with the PFEDH extending along the sigmoid sinus groove evaluated by MR imaging (MRI) and MR venography (MRV). T2-weighted coronal MRI can diagnose both patency of the sigmoid sinus and epidural hematoma extending along the sinus groove. Phase-contrast MRV (PC-MRV) is also useful to evaluate the flow state in the dural sinuses but it should be diagnosed carefully whether low visualization of the dural sinus means only functional flow impairment or organized occlusion due to thrombus. To avoid an unnecessary anticoagulant therapy that may worsen epidural hematoma, it is important to recognize the pitfall that PFEDH extending along the sinus groove is easy to misdiagnose for a dural sinus thrombosis.