PMC8326067_01
Right vestibular schwannoma with maximum diameter of 28 x 25 x 26 mm. MRI T2 image of Gamma Knife Radiosurgery (GKR) treatment planning (a). MRI T2 image 21 months after GKR (b). Extensive peritumoral brain edema with fourth ventricle compression is evident.
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F1
A brain MRI revealed an acoustic neuroma in the right cerebellopontine angle (CPA), Koos Grade III, with peritumoral edema and brainstem compression [Figure 1a]. A brain MRI showed an extensive cerebellar PTBE with fourth ventricle compression and obstructive hydrocephalus [Figure 1b].
PMC8326067_02
Right vestibular schwannoma with maximum diameter of 41 x 35 x 35mm. MRI T1 contrast-enhanced image before first surgery (a). MRI T1 contrast-enhanced image of Gamma Knife Radiosurgery (GKR) treatment planning (b). MRI T2 image at 18 months after GKR (c); peritumoral brain edema (PTBE) in the right cerebellar hemisphere and brain stem is clearly visible. MRI T2 at image 3 months after surgical removal showing complete PTBE resolution (d).
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F2
A 45-year-old woman with right-sided hearing loss underwent a brain MRI that showed a right CPA mass [Figure 2a]. The procedure was frame-based (Gamma Knife Perfexion) [Figure 2b]. A brain MRI revealed an important increase in the size of the residual tumor with large PTBE in cerebellum and brainstem with fourth ventricle compression and hydrocephalus [Figure 2c]; this potentially life-threatening condition led us to prompt surgery. Three months after surgery, brain MRI showed the complete reabsorption of PTBE in cerebellum and brainstem [Figure 2d].
PMC8326067_03
Right clinoid meningioma. MRI T1 contrast-enhanced images before (a) and after (b) surgery showing complete removal of the meningioma. MRI flair images highlight peritumoral brain edema before surgery (c) and at 2 months after surgery (d); an almost complete resolution is clear.
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F3
The lesion was about 2 cm diameter with moderate PTBE [Figure 3a]. Histopathological examination confirmed a meningothelial meningioma (Grade I WHO) [Figure 3b]. A brain MRI performed 2 months after surgery showed near complete resolution of the pre-existing PTBE [Figure 3c and d].