High resolution computed tomography of the temporal bone: preliminary experience.
ABSTRACT High Resolution Computed Tomography (HRCT) can demonstrate the detailed anatomy and pathology of the temporal bone and is fast becoming an important imaging modality in the diagnosis and preoperative management of our local patients with temporal bone diseases. We present our experience in the usage of HRCT in temporal bone lesions in Tan Tock Seng Hospital, using 8 cases as illustration. The protocol that we used to obtain the images is described. We also give an overview of those clinical conditions whereby HRCT can provide information which will help surgeons in the management of their patients. These clinical conditions are hearing loss, external auditory canal atresia, middle ear inflammation/cholesteatoma, temporal bone trauma, pulsatile tinnitus and vascular tympanic membrane.
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ABSTRACT: Cholesteatoma is traditionally diagnosed by otoscopic examination and treated by explorative surgery. The need for imaging in an uncomplicated case is contentious. This study assesses the usefulness of a pre-operative high-resolution CT scan in depicting the status of the middle ear structures in the presence of cholesteatoma. The surgical findings of 36 ears with cholesteatoma operated on by the first author were retrospectively compared with the CT findings reported on by the second author. The following were analysed: diagnostic features of cholesteatoma on CT, status of the middle ear structures (ossicles, facial nerve canal, semicircular canals and tegmen tympani), and presence of any anatomical variations and disease complications. All cases had at least 1, and 30 cases (83.3%) had all, of the following radiological features: (a) a non-dependent tissue mass, (b) a location typical for cholesteatoma and (c) bony erosion. The radiosurgical agreement was excellent for the malleus (kappa statistics, k=0.83), stapes (0.94) and semicircular canals (0.8), good for the incus (0.62) and tegmen (0.65), but poor for the facial nerve canal (0.3). Potential surgical hazards detected by the scans included: low lying dura, high jugular bulb, anterior lying sigmoid sinus, facial nerve dehiscence and other situations brought about by the destructive nature of the lesion. There is good to excellent radiosurgical correlation in cholesteatoma for most middle ear structures except for the integrity of the facial canal. The scan alerts the surgeon to potential surgical dangers and complications of disease. High-resolution CT scan is an important investigative tool prior to cholesteatoma surgery.Singapore medical journal 05/2001; 42(4):155-9. · 0.63 Impact Factor