Limitations of computed tomography in the investigation of acoustic neuromas

Cerebellopontine angle meningiomas: clinical manifestations and diagnosis

Cerebellopontine angle (CPA) meningiomas constitute about 1% of intracranial meningiomas. The clinical aspects of a series of 32 patients with surgically confirmed CPA meningiomas are analyzed. The most common symptoms at the time of the initial evaluation were from the eighth cranial nerve (unilateral hearing loss--24 patients, vertigo or imbalance--19 patients, tinnitus--11 patients), and the fifth cranial nerve (altered sensation--9 patients, facial pain--5 patients). On examination, the most common findings were absent caloric response (19 patients), nystagmus (16 patients), diminished facial sensation (14 patients), ataxia (13 patients), reduced hearing (9 patients), and facial weakness (9 patients). There was often a long interval from the onset of symptoms to the correct diagnosis of a tumor. Brain stem auditory evoked potentials, blink reflex testing, posterior fossa myelography, computerized tomographic scanning, and angiography were abnormal in all patients in whom the test was done, but all tests were not performed on all patients. Computerized tomographic scanning and angiography are important for definitive diagnosis and for planning surgical treatment. The histopathology of the temporal bone was studied in three patients with meningiomas in the region of the internal auditory meatus.

CT of meningiomas on the Posterior surface of the petrous bone

A detailed analysis of the CT findings in 16 surgically verified cases of meningioma of the posterior surface of the petrous bone is presented. The results indicate that a correct preoperative diagnosis is possible in almost every case. Frequently occurring specific CT criteria for meningioma of the posterior surface of the petrous bone include: hyperdense, homogeneously enhancing, extra-axial, CPA mass; inverse relationship between precontrast attenuation value and degree of contrast enhancement of the tumor; oval shape; obtuse angle between lateral tumor border and posterior surface of petrous bone, and evidence of transcisternal supratentorial tumor extension. Infrequently occurring specific CT criteria include: tumor calcification; hyperostosis or exostosis of the posterior surface of the petrous bone; a comma-shaped tumor configuration in cases with transcisternal tumor extension and evidence of transtentorial tumor extension. Oxygen CT cisternography is the most sensitive and reliable technique for detecting small tumors. The CT differential diagnosis of meningioma of the posterior surface of the petrous bone is discussed.

Computerized axial tomography in the assessment of thyroid cartilage invasion by laryngeal carcinoma: a prospective study

The purpose of this study was to assess the value of computerized axial tomography (CAT) in canine larynges that exhibit controlled surgical defects, and in 18 patients with biopsy-proved epidermoid carcinoma of the larynx who were studied prospectively. Five canine larynges with sequential surgical defects of 0 mm, 5 mm, 10 mm, and 15 mm were studied by CAT in order to evaluate our ability to identify defects in the thyroid cartilage. A 5-mm collimator with overlapping sections at 3-mm intervals and a 13-mm collimator with 5-mm overlapping sections were both used for each stage of the experiment. Results show significantly improved resolution with the 5-mm collimator compared with the 13-mm unit. In the human study group, results demonstrated excellent (100%) soft-tissue tumor site correlation. It appears from this study that we still lack a highly reliable radiographic technique for evaluating preoperatively with accuracy the integrity of the thyroid cartilage in the patient with carcinoma of the larynx.

Intracanalicular neurilemmomas: clinicopathologic study

Twenty-five patients with intracanalicular neurilemmonas were studied, the largest series yet reported. The tumors were most frequent in men by a ratio of 2:1, occurred more often on the left acoustic nerve, generally associated with long duration of symptoms and were equally distributed in the third to fifth decades, but the prevalence slightly increased in the sixth and seventh decades. A shorter length of illness occurred in younger persons as well as most patients with von Recklinghausen's disease. The length of illness ranged from six months to 35 years. Symptoms generally were limited to the auditory nerve except in three instances of involvement of the facial nerve. These three cases were the only ones with preoperative facial palsy. Posterior fossa myelogram was the most useful diagnostic acid. The rate of growth in one patient was estimated to be 1 to 2 mm per year by serial study of myelograms, but the growth rate is probably variable. CT scans were not useful in detecting small tumors. Histologically, most tumors less than 1 cm in diameter were primarily composed of Antoni type A tissue. Vascular malformations were found within the tumor in three cases. Altered blood vessels are the mechanism whereby characteristic changes occur in the cerebrospinal fluid (CSF). Small tumors generally lack blood vessels, hence are less often associated with abnormal CSF.

Computerized tomography or paranasal sinus neoplasms

Computerized tomography represents a new and valuable diagnostic tool to the otolaryngologist and head and neck surgeon in several ever-increasing aspects of his clinical practice. This report presents CT scans utilizing the E.M.I 5005 body scanner on patients with neoplasms of the paranasal sinuses presenting to the Head and Neck Service of The University of Texas System Center M. D. Anderson Hospital and Tumor Institute. Only patients undergoing surgical resection of such lesions are included so that actual operative and surgical pathological findings can be used for critical comparison of diagnostic information derived from polytomography and computerized tomography. Seven illustrative cases are presented. In general, computerized tomography has been found to be equal to polytomography in assessing bone destruction or involvement by tumor, and superior to polytomography in determining accurately the soft tissue extent of disease. CT scanning, however, has been found to have limitations in the delineation of soft tissue disease in areas of high contrast in tissue density, and in the evaluation of possible intracranial tumor extension in isodense, avascular lesions.

Intra and extracranial meningiomas involving the temporal bone

Meningiomas involving the temporal bone are very rare. Until 1964, only 39 cases had been reported in the world literature. Most series reported are very small and a physician is unable, based on his own experience, to acquire a sufficient knowledge about this entity and may raise serious doubts regarding the diagnosis and management of these tumors. In the past nine years the author has encountered five cases of meningiomas involving the temporal bone. This became a stimulus for a thorough research of the world literature of meningiomas in general, with emphasis on temporal bone involvement. Nine more cases were collected from cooperative physicians with whom the author has been associated. These 14 cases are the clinical material analysed in this study. This thesis is divided into three sections: 1. Exhaustive review of the world literature on meningiomas with emphasis on involvement of the temporal bone. 2. A detailed presentation and discussion of the clinical material stressing the importance of the newer diagnostic methods available and the most modern microsurgical techniques used in otological and neurological surgery procedures, applied to the treatment of those lesions. A light microscopic histopathological study of all cases reported is presented. Electronmicroscopy demonstrates the true intracellular nature of an atypical, recurrent meningioma occurring in a child. 3. A critical evaluation of the cases presented and the value of the diagnostic and therapeutic methods applied in this series of patients are here analysed. Conclusions are then drawn based on the experience and knowledge accumulated in this study. The histopathological diagnosis of meningiomas sometimes is difficult. Probably those tumors involve the temporal bone more commonly than has been reported in the literature. Some of these lesions probably are being misdiagnosed as chemodectomas or other neoplasias. Computerized axial tomography, particularly applied to the diagnosis of brain lesions, is the major break-through of recent modern medicine. A noninvasive technique, when used with contrast enhancement, offers great diagnostic possibilities. Early diagnosis of meningiomas and their complete surgical excision are the key factors necessary for a successful result with a good prognosis and a low recurrence rate. Although these tumors are classically considered radioresistant, radiotherapy may play a role in the treatment of incompletely excised lesions or in patients of a poor surgical risk. Further experiences and time will probably lead to more definite conclusions regarding the role of radiation therapy or the combined surgical and postoperative radiation treatment. Of all brain tumors, meningiomas offer the best prognosis.