ABSTRACT
Objective To study the CT and MRI findings of schwannoma in tIle sinonasal region and evaluate their clinical application.Methods All 12 cases of schwannoma locating in the sinonasal region were verified by pathology.r111e CT images in all 12 cases and MRI findings in 10 cases were analyzed retrospectively.Results Of the 12 cases of schwannoma in the sinonasal cavity.11 were benign and l was malignant.The tumors located in the nasoethmoid region in 4 cases.in the maxillary sinus in 3 cases and in the maxillary.ethmoid and sphenoid sinuses in 2 cases.The lesion of the remaining 3 cases involved maxillary sinus and hasal cavity,sphenoid sinus and choana respectively.The lesions with well-defined margin showed elliptic shape in 4 cases,irregular shape in 8 cases.On CT,the lesion resulted in dilatation of the affected sinonasal cavity with remodeling,thinning and displacement of the bony wall.In addition.local bony absorption was detected in 8 cases and bony destruction was found in 1 case.The lesions revealed homogeneous density in 10 cases and inhomogeneous in 2 on precontrast CT.Two cases showed heterogeneous enhancement on postcontrast CT. On MR T1WI,schwannoma in the sinonasal region demonstrated isointense signal compared to brain in 10 cases with patchy and nodular low signal intensity in 3 cases and patchy hish signal intensity in 2 cases.On T2 WI.the lesion showed heterogeneous isointense singal in 7 cases and slightly hyperintense signal in 3 cases.Stippled and patchy hyperintense signal was seen in 9 cases and well-defined and regular nedular high intense signal in 6 cases.Patchy low signal intensity was found in 2 cases corresponding to the high signal intensity on MR Tl WI.In addition,liquid-iquid level was identified in one case.The lesion displayed rooderate to marked inhomogeneous enhancement on contrast-enhanced MR images in 9 cases and marked homogeneous enhancement in one case.The time.intensity curve of dynamic contrast enhancement of MRI showed plateau type in 2 cases.In this group,the lesions were complicated with obstructive parasinusitis in 6 cases.which showed hypointense signal on MR T1 WI,hyperintense signal on T,WI and peripheral enhancement on postcontrast MRI.MRI showed the extent and other associated changes of the lesions more clearly compared to CT Conclusions Bone remodeling.thinning and absorption on CT and Patchy and noduhr high signal intensity on MR T2WI without postcontrast enhancement were typical manifestations of schwannoma in the sinonasal region.Combined findings of CT and MRI call provide more comprehensive information for the diagnosis and therapy.
ABSTRACT
Objective To study the direct oblique images of normal temporal bones such as facial nerve canal, ossical chain, otic capsule and other structures. Methods 63 normal temporal bones were examined on direct oblique CT. The images were compared with cadaveric bone. Results The direct oblique images clearly showed the external auditory meatus, epitympanum, mastoid antrum, ossical chain, mastoid facial canal, otic capsule, internal auditory canal in 63(100%) temporal bones, the tympanic facial canal in 42(66 7%), the anteriorgenu in 55(87 3%), and the vestibular aqueduct in 58(92 1%). Conclusion Besides axial and coronal CT, direct oblique CT scan is also an important imaging method, which may provide valuable evidence for diagnosis and operation about ear diseases.