Biomedical subjects
Publications and source records attributed to C Virapongse.
Two cases of intracerebral pneumatocele following trauma are presented. One to two months after initial treatment both patients had deteriorating neurologic status. The diagnosis was made by radiography. When a pneumatocele is suspected clinically, computed tomography can play a vital role in determining the precise location of the gas collection, its relationship to the fracture site, and the amount of mass effect on the brain.
The pneumatization of 141 "normal" temporal bones on computed tomography (CT) was evaluated in 100 patients (age range, 6-85 years). Because of the controversy surrounding the sclerotic squamomastoid (mastoid), temporal bones with this finding were discarded. A CT index of pneumatization was based on the pneumatized area and the number of cells seen within a representative scanning section. Results suggest that squamomastoid pneumatization follows the classic normal distribution and does not correlate with age, gender, or laterality. A high degree of symmetry was found in 41 patients who had both ears examined. In 35% of all temporal bones, the petrous apex was pneumatized, concordant with the findings of other investigators. Pneumatization extending into other regions of the temporal bone corresponded linearly with squamomastoid pneumatization. Air-cell configuration was variable. Air-cell size tended to increase progressively from the mastoid antrum. The scutum "pseudotumor" appearance caused by incomplete pneumatization was seen frequently, and should not be mistaken for mastoiditis or an osteoma. Thick sections producing partial-volume effect may also produce this spurious finding. Therefore, when searching for mucosal thickening due to mastoiditis, large air cells should preferably be analyzed.
We describe a newborn with multiple congenital anomalies due to the Amniotic Band Disruption Complex. Cerebral computerized tomography and plain films of the extremities corroborated the clinical diagnosis. The purpose of this case report is to alert the radiologist to the varied radiographic appearance of this little known entity and to provide a historical and embryologic background.
We used computed tomography to detect and localize foreign bodies in two unusual cases of penetrating injury to the eyes. In one case, a large broken twig appeared to have penetrated the globe and the inferior rectus muscle; in the other, the globe was ruptured by many glass shards . In the first case surgery showed the computed tomographic impression to be incorrect. The globe and the inferior rectus muscle were intact and vision and motility were normal postoperatively. In the second case, swelling made direct visualization impossible, and computed tomography was used to locate the foreign bodies.
Failure to develop of the corpus callosum and the neighboring midline structures results in abnormal proximity between the interhemispheric fissure (IHF) and the third ventricle. We have called this finding the IHF sign of dysgenesis of the corpus callosum (DCC). In a retrospective study of 39 cases the presence of the IHF sign was assessed in conjunction with the other well recognized CT manifestations of the disorder. These are: (a) lateral ventricles: pointing of the frontal horns, disproportionate enlargement of the occipital horns and separation of bodies of the lateral ventricles; (b) third ventricle: enlargement, elevation and anterior displacement; and (c) interventricular foramen: enlargement. We found that the IHF sign was present concurrently with the other CT signs of DCC in all 35 cases (100%) where the quality of the CT scans permitted its satisfactory evaluation; in the remaining four the sign could not be assessed because of the unsatisfactory quality of the CT scans. Our study confirms that the IHF sign is an additional reliable CT feature of DCC.
The authors describe 2 diffusely invasive prolactin-secreting pituitary adenomas which produced marked destruction of the base of the skull thought to be diagnostic of chordoma on computed tomography (CT). Failure to recognize this pattern led to biopsy, which was diagnostic. The authors emphasize the need to recognize this rare growth pattern of diffusely invasive pituitary adenoma on CT.
A case of redundant lumbar nerve roots associated with lumbar canal stenosis is described. At myelography, the redundant nerve roots proximal to a site of blockage were noted to disappear on flexion and extension while similar redundancy developed distally. The etiology of this condition is discussed along with the differential diagnosis.
Computed tomography and plain film findings in a neonate with a congenital orbital teratoma are presented. The characteristic radiographic findings of this rare tumor are discussed, and the value of preoperative CT assessment of tumor extension is stressed.
This study of 34 normal ears was conducted in order to define more precisely the normal computed tomographic (CT) anatomy of the osseous external auditory canal. Great variability was found in canal configuration and its relationship to the temporal squama. The understanding of normal CT appearance of the various fissures along the anterior wall of the external canal is important to avoid mistaking fissures for fractures.
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We report a case of cerebellar glioblastoma multiforme in a young adult. The rarity of this tumor in this location is discussed along with its computed tomographic appearance.
We report a case of an extramedullary plasmacytoma arising from the nasopharynx. The computed tomographic appearance of this rare tumor is discussed.
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Forty patients with neurological deficits from cervical spine trauma had cervical myelography with metrizamide, gas, iophendylate, or a combination thereof. At a low dosage (less than or equal to 1.25 g I), metrizamide was found to be not only the most effective in demonstrating the spinal cord but also safe if used with a C-arm biplane fluoroscopic unit which has tomographic capability.
Sixty-five patients with suspected ear disease were examined with CT, and abnormalities were detected in 42 of them; 58 of these patients also had pluridirectional tomographic examinations. Eighteen of the patients in whom abnormalities were detected underwent exploratory surgery. CT was useful in the diagnosis of tympanic membrane swelling, fluid in the middle ear, cholesteatoma, granulation tissue, and adhesions. The superior contrast resolution of CT allowed for the visualization of ossicles when they were surrounded by an inflammatory mass or by blood. In trauma cases, axial images facilitated visualization of longitudinal fractures, which frequently pass through the geniculate ganglion of the facial nerve. CT and pluridirectional tomography were comparable in the demonstration of disease that involved the mastoid air cells, although fluid in air cells was more easily demonstrated by CT. Pluridirectional tomography was superior to CT in the demonstration of bone destruction; CT, however, was more sensitive in the diagnosis of lateral semicircular canal fistula. Based on this analysis, we recommend that these two modalities be used in a complementary fashion to evaluate suspected middle ear disease.
A patient who cannot lie prone for myelography can be strapped to a pneumoencephalographic chair and rotated from an upright to supine position. Cervical lordosis is maintained and contrast material can be pooled in the cervical region or thoracic spinal canal.
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Pulsatile tinnitus is a rare presenting symptom in patients with enlarged jugular bulbs. We will describe three young women presenting with right pulsatile tinnitus associated with a megabulb deformity of the temporal bone. After extensive radiologic and audiologic evaluation, no vascular or bony abnormalities could be identified. All three patients demonstrated pulsatile bruits over the right temple. Pulsatile tinnitus disappeared with ipsilateral jugular compression suggesting flow rather than pressure to be responsible for abnormal auditory symptoms. This observation formed the basis of our treatment recommendations. Because of progressively debilitating pulsatile tinnitus, two patients elected right internal jugular vein ligations under local anesthesia. Both patients were relieved of tinnitus. We conclude that jugular vein ligation can be a safe and effective surgical treatment for pulsatile tinnitus resulting from a jugular megabulb deformity, provided two criteria are met: 1. The presence of an expanding tumor is ruled out. 2. The presence of contralateral venous drainage is established by angiography or brain scan. Anatomic and functional hemodynamic considerations of brain circulation will be emphasized in the discussion of our treatment rationale.