Biomedical subjects
Publications and source records attributed to J D Acker.
A young woman with chronic sciatica was found to have an intrapelvic sacral plexus nerve sheath tumor. Computed tomography of the pelvis was used to delineate this unusual site of tumor development. The case report and a discussion of pelvic nerve sheath tumors are presented.
Continued refinements in the technique of high resolution computed tomographic scanning now allow the study of the pathology of intratemporal tumors of the facial nerve. The normal anatomy of this area and a selected case of facial nerve neuroma diagnosed with high resolution computed tomography are presented.
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In evaluating over 300 patients with sellar and parasellar lesions, the computed tomographic (CT) appearance of the cavernous sinus was studied. Optimal visualization of the cavernous sinus was obtained with continuous contrast enhancement of both axial and coronal tomograms. The coronal projection and reformatted views provided imaging of the cranial nerves within the cavernous sinus. In addition to the physiologic CT appearance of the cavernous sinus, a variety of pathologic conditions are illustrated. CT criteria suggesting an abnormal cavernous sinus are: (1) asymmetry of size; (2) asymmetry of shape, particularly the lateral wall; and (3) focal areas of abnormal density within the sinus.
We present 4 children with brain tumors that were missed or incompletely characterized conventional computerized tomography (CT) scanning. Using high resolution CT with high dose contrast and three-dimensional reconstruction, we were able to define the anatomy of each tumor and its associated aberrant vasculature. High resolution CT scanning with reconstruction is very helpful in diagnostic problems in which conventional CT scanning fails to provide a clear diagnosis.
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Seventy patients suspected clinically of having an acoustic tumor were evaluated using the computed tomographic (CT) scan as the initial neuroradiological procedure, followed by CO2 contrast CT cisternography in cases where the intravenous contrast-enhanced scan did not reveal any lesion. Forty-eight gas CT cisternograms revealed 10 small acoustic tumors, 2 of which were totally intracanalicular. The authors present a review of the basic CT anatomy of the temporal bone as it relates to acoustic tumors. Based upon the ease of performance of the procedure, the low postexamination morbidity, and the excellent diagnostic results, CO2 CT cisternography is recommended as the procedure of choice in the diagnosis of small and intracanalicular acoustic tumors.
Contrast enhancement provides valuable information in cranial computed tomography. We report the use of high-dose continuous contrast infusion as a means of consistently demonstrating major perisellar cerebral vasculature. This method was utilized in examining 73 patients, and three illustrative cases are presented. We propose that this technique be performed as the initial radiographic procedure in evaluating sellar and perisellar lesions. Results of clinical, laboratory, and CT examinations may necessitate additional studies including sellar complex motion polytomography, cerebral angiography, metrizamide CT cisternography, or pneumoencephalography. However, employing the CT techniques described, the role of invasive neuroradiographic procedures in the preoperative evaluation of the sellar and perisellar region requires reconsideration.
A family is reported in which 3 siblings, 2 with the same and the third with a different father, were demonstrated to have cerebral arteriovenous malformations.
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Eight of 115 patients with empty sella had concurrent galactorrhea. All 8 patients had abnormal sellae, and the diagnosis of empty sella was made by polytome pneumoencephalography. There were no obvious endocrine dysfunctions, but 2 patients had elevated prolactin levels. One mechanism for production of galactorrhea may involve compression of the hypothalamus and/or pituitary stalk; this was suggested by most of our observations. There may be a coincidental association of empty sella with galactorrhea, and this association is probably more common than previously noted. Evaluation of patients with galactorrhea and abnormal sellae by polytome pneumoencephalography is emphasized.
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Computed tomography (CT) is the procedure of choice for initial evaluation of patients suspected of having chiasmal or perichiasmal lesions. Over 1000 patients were examined with high resolution CT, using axial and coronal scans, contrast enhancement, multiplanar reformations, and, when indicated, metrizamide CT cisternography. The normal anatomic appearance of the chiasm and neighboring structures are: (1) symmetric or asymmetric enlargement of the chiasm; (2) areas of abnormal density, without or with contrast enhancement, in the chiasm or perichiasmal region; (3) alteration of the suprasellar cistern; and (4) distortion of the anterior-inferior third ventricle.
In a prospective cross-sectional study, we used computerized volumetry of magnetic resonance images to examine the patterns of brain aging in 148 healthy volunteers. The most substantial age-related decline was found in the volume of the prefrontal gray matter. Smaller age-related differences were observed in the volume of the fusiform, inferior temporal and superior parietal cortices. The effects of age on the hippocampal formation, the postcentral gyrus, prefrontal white matter and superior parietal white matter were even weaker. No significant age-related differences were observed in the parahippocampal and anterior cingulate gyri, inferior parietal lobule, pericalcarine gray matter, the precentral gray and white matter, postcentral white matter and inferior parietal white matter. The volume of the total brain volume and the hippocampal formation was larger in men than in women even after adjustment for height. Inferior temporal cortex showed steeper aging trend in men. Small but consistent rightward asymmetry was found in the whole cerebral hemispheres, superior parietal, fusiform and orbito-frontal cortices, postcentral and prefrontal white matter. The left side was larger than the right in the dorsolateral prefrontal, parahippocampal, inferior parietal and pericalcarine cortices, and in the parietal white matter. However, there were no significant differences in age trends between the hemispheres.
We analyzed the clinical constellation of signs and symptoms and the radiographic studies of 17 patients with histologic verification of cavernous sinus metastases. Although most patients presented with acute, unilateral, painful ophthalmoplegia, and with a rapidly progressive course, the clinical diagnosis of metastatic disease was often delayed. This was probably due to the fact that, in the majority of patients, cavernous sinus symptoms were either the first expression of an unknown malignancy or the first manifestation of metastatic disease in those with a known primary. Computed tomography was found to be an indispensable diagnostic aid. In 16 of the 17 patients CT established the presence of an enhancing mass in the cavernous sinus sometimes associated with bone erosion. Thin section, contrast enhanced high resolution CT in axial and coronal projections represents the imaging procedure of choice for metastatic disease to the cavernous sinus.
We report a rare tumor of the nasopharynx in the neonate: the teratoid or hairy polyp. In addition to the traditional modes of evaluation (barium swallow, plain radiography, and indirect laryngoscopy), CT and magnetic resonance were used to assess this unusual cause of respiratory distress and vomiting in a newborn.
BACKGROUND AND PURPOSE: The human brain exhibits a complex pattern of differential aging. The purpose of this study was to examine whether age differences in the volume of cerebellar regions and the ventral pons are differential or generalized, whether the age-related shrinkage is linear or exponential, and whether there are sex differences in the size of the cerebellum and pons. METHODS: The volumes of the cerebellar hemispheres (excluding the vermis and the peduncles), the vermis, and the ventral pons were estimated from the prospectively acquired MR scans of 190 healthy volunteers (aged 18-81 years). The relation between regional volumes, age, and sex was assessed while taking into account differences in body size (height). RESULTS: We found a moderate age-related reduction in the volume of the cerebellar hemispheres and the cerebellar vermis. In contrast to previous findings that suggested differential vulnerability of the posterior vermis, the age-related shrinkage of the vermian lobules was uniform-about 2% per decade. In accord with all reports in the literature, the size of the ventral pons was unrelated to age. The volume of the cerebellar hemispheres, the vermis, and the ventral pons were larger in men, even after adjustment for height. The magnitude of the sex difference was the largest in the hemispheres and the anterior vermis, and the smallest in the lobules VI-VII (declive-folium-tuber). CONCLUSION: Moderate age-related shrinkage of the cerebellum and lack of age-related differences in the ventral pons are robust phenomena. However, in all likelihood, the effects of age on the cerebellum are not differential but uniform. The cerebellum and the pons are larger in men than in women and the difference is especially pronounced in the cerebellar hemispheres and the anterior vermis.
Evaluation of over 255 patients with sellar and parasellar lesions allowed study of the computed tomographic (CT) appearance of the cavernous sinus. Optimal visualization of the cavernous sinus was obtained with continuous contrast enhancement of both axial and coronal tomograms. The coronal projection provided imaging of cranial nerves with the cavernous sinus. The intracavernous carotid artery was seen only if it were calcified or encased by tumor extending into or invading the sinus. CT criteria suggesting an abnormal cavernous sinus are: (1) asymmetry of size, (2) asymmetry of shape, particularly the lateral wall, and (3) focal areas of abnormal density within the sinus. The neurovascular anatomy of the cavernous sinus is reviewed and correlated with CT findings. Discrepancies between anatomic and CT appearance are discussed.