Diagnosis of Acoustic Tumor by CT-Scanning

Abstract

Early diagnosis of acoustic tumors plays an important role in minimizing the disorder caused by operation and in the aspect of rehabilitation. It can be said that the otorhinolaryngologists' mission is to make an early diagnosis of acoustic tumors. A present, however, unfortunately, acoustic tumors are only rarely detected at the stage where the affected area is confined to the internal auditory meatus, i. e, so-called “ear tumor”. In many cases of early acoustic tumors, there are no abnormal objective findings except perceptive deafness and a reduced or extinct response on caloric nystagmus examination. On many occasions, neuro-otolbgical examination does not lead to a definite diagnosis of acoustic tumor but only suggests its presence. Therefore, we cannot but resort to diagnostic imaging in order to confirm the presence or absence of a tumor. As a next step, CT is performed following plain roentogenography, pluridirectional tomography, etc. Conventional CT where the limits of the detectable image in the diameter of the tumor have been considered to be 1.5-2cm is, however, not helpful for early diagnosis. For this reason, we have been troubled with a gap between what the functional test results indicate and CT-findings. We are now equipped with CT (from the Review of metrizamide cisternograms produced by GE CT/T) which seems to adequately fill such a gap and be useful for early diagnosis of acoustic tumors. We believe that CT-scan will reveal a greater number of cases of “ear tumor”.