CT and MR Features of the Intracranial Schwannomas

Abstract

Results: Schwannomas arose from the acoustic nerve(n = 18) , the trigemin a l nerve(n = 2) , the glossopharyngeal -vagal-accessory nerve complex (n=2) , and the olfactory nerve(n=1l. Intracranial schwannomas were well defined , lobulaled and inhomogeneously or homogeneously enhancing masses on CT and MR , and were located along the course of the specific cranial nerve. Acouslic schwannomas involved both the internal auditory canal(IAC) and the cerebellopontine angle(CPA) in 14 cases , the IAC in three , and the CPA in two. Two trigeminal schwannomas involved both middle and posterior cranial fossa and were in the shape of a dumbbell One of the two schwannomas that invelved lower cranial nerve complex(9 -11 th) was located in the medullary cistern and jugular foramen ; the other was located in the central posterior cranial fossa. A case of olfactory schwannoma was localed in lhe right cribriform plate. The precontrast CT scan showed low density in 13 cases (62 % ), isodensily in seven(33%) and high density in one(5%). On postcontrast CT scan , enhancement was seen in 20 cases(95 % ). Of lhe 15 cases with MR , 12 had low signal intensity on T1 weighted image and 14 had high signal intensity on T2 weighted image. MR imaging after Gd-DTPA infusion showed enhancement in 14 cases Enhancement was inhomogeneous in 14 cases on CT and in 13 on MR. Of 24 cases , intratumoral necrosis was seen in 19, ring enhancement in five and severe cystic change in one. Other findings were intratumoral calcification(21 %) , hemorrhage(8%) , pressure bony erosion(70.8 % ), midline shift(58 % ), peritumoral edema(29 % ) and hydrocephalus(33%). On MR , there was in all 15 cases a peritumoral low signal intensity rim on T1-and T2-weighted images and on a T1 weighted image following gadolium infusion.

Manufacturing of spherical activated carbons using anion exchange resins and analysis of the properties

“…Among them, activated carbons are one of the most representative adsorbents with low production costs and properties such as abundant micropores, large surface areas, high adsorption performance, acid/base, and thermal stability [1]. Due to such properties, activated carbons are widely used in diverse liquid-phase and gas-phase processes such as the treatment of heavy metals in wastewater and landfill leachate, CO 2 capture, hydrogen storage, super capacitor and VOCs adsorption [2][3][4]. Since activated carbons are usually made from natural materials such as coconut shells, coal, wood, and petroleum pitch, they are in the form of fine powder or low-stability granules.…”