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Four families were selected randomly on the basis of the occurrence of spina-bifida cystica and/or spina bifida occulta in one or more family members. Sixty-three relatives were studied clinically and roentgenologically; their roentgenograms were evaluated blindly. Twenty-eight were clinically and roentgenologically normal; 35 were diagnosed as having spina bifida occulta (SBO), spina bifida cystica (SBC), vertebral anomalies, and/or external defects usually interpreted as evidence for SBO. Excluding one proband we found the frequency of SBO to be 19/51 (37%) and the frequency of all types of spinal/vertebral defects (excluding five probands) to be 30/58 (52%). The distribution of these defects in the four families was analyzed using likelihood methods corrected for random ascertainment. The log likelihood values for sporadic, recessive, and dominant models were -26.69, -20.95, and -18.90, respectively, indicating a higher likelihood of autosomal dominant inheritance than sporadic occurrence or recessive inheritance. The penetrance probability in this dominant model, estimated by maximum likelihood, is 0.749 +/- 0.100. Further examination of these data suggest that SBO and SBC represent different expressions of the same dominant gene in these kindreds.

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The relationship between severity of diffuse cerebral atrophy determined by computed tomography (CT) and severity of cognitive impairment was examined in 55 men, 50 to 77 years old. Partial correlations, controlling for the effects of age and education, indicated that increased cerebral atrophy was associated with decline in orientation, recent memory, and general level of intellectual functioning. Correlations between degree of atrophy and decline in immediate and remote memory were not significant. Despite significant associations between cerebral atrophy and some aspects of intellectual functioning, considerable variance in performance on cognitive tasks was not explained by cerebral atrophy. Therefore, the degree of diffuse cortical and central atrophy observed on CT scan did not closely predict the degree of cognitive dysfunction, nor did the observation of cerebral atrophy necessarily indicate the presence of dementia.

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Computed tomography is ideal for demonstrating orbital masses. It provides information regarding lesion location and involvement of intraorbital structures. It therefore can be used in both staging and follow-up of orbital lesions. Mass location, attenuation characteristics, form, and presence or absence of contrast enhancement all may aid the radiologist in the differential diagnosis of orbital lesions by CT. However, this review of lateral orbital masses illustrates that the differential diagnosis can be quite varied. Careful correlation with history and clinical findings may lead one to the proper diagnosis; however, often the exact nature of a lateral orbital mass must await histologic confirmation.

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Computed tomography (CT) both with and without contrast agents has been used to diagnose syringomyelia. We report a case in which the diagnosis was made by injection of metrizamide into a ventriculoperitoneal shunt. Continuity of the syringomyelic cavity with the ventricular system was demonstrated. This case supports the hydrodynamic concept of syringomyelia formation and illustrates a potentially useful approach to its diagnosis.

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Recent software additions to a CT scanner with a continuously rotating tube-detector system allow uninterrupted data collection after rapid intravenous contrast material injection. The highly flexible computer program can accommodate as many as 16 consecutive 3 sec scans, or various time intervals can be inserted between individual scans. A variety of intracranial lesions was studied in 35 patients using this dynamic scanning technique and the enhancement of normal gray and white matter was evaluated. Potential applications of this technique are discussed, with emphasis on the possibility of differentiating certain cerebral lesions by their early enhancement patterns and evaluating cerebrovascular occlusive disease.

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When identified on nonenhanced computed tomography (CT), a long, thin band of increased attenuation in the region of the falx cerebri (the falx sign) has been regarded as evidence of subarachnoid hemorrhage. Shorter, wider, or wedge-shaped interhemispheric fluid collections of blood-equivalent attenuation have been considered representative of a subdural hematoma in an abused child. The superior sagittal sinus, straight sinus, and falx cerebri are identified on unenhanced CT scans of pediatric patients without clinical or radiographic evidence of trauma, subarachnoid hemorrhage, bleeding diathesis, or other abnormalities. These structures are often visualized where atrophy or degenerative diseases of the brain provide an adjacent region of diminished attenuation. With the spatial and density resolution of new CT scanners, visualization of the falx cerebri and its dural sinuses is normal.

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One hundred children varying in age from newborn through four years were studied without sedation or anesthesia using a three-second CT scanner. Satisfactory scans were obtained in 99. The elimination of the hazards and morbidity of intramuscular sedation more than compensated for the extra effort required to scan these youngsters without any preparation.

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Gross malformation of the central nervous system (CNS) is rare in Down syndrome (DS). To our knowledge we report for the first time the association of trisomy 21 and holoprosencephaly. Because of the low probability of chance concurrence due to unrelated causes, a causal relationship between these two conditions in the patient must be presumed. The anatomic similarity of the holoprosencephalic defect in this infant to that seen in others with autosomal dominant, recessive, sporadic, or syndromal forms of holoprosencephaly, supports the hypothesis that: a) this CNS defect is a causally nonspecific developmental field complex (DFC); b) the increased incidence of such DFC's in the DS represents the result of a nonspecific decrease of developmental homeostasis [Waddington, 1975] due to autosomal aneuploidy.

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Standard axial transverse orbital computed tomography scans show the medial and lateral rectus muscles very well but section the superior and inferior rectus muscles obliquely. Determining enlargement of the superior and inferior recti in Graves' disease can therefore be difficult on axial transverse scans. We have obtained sagittal, coronal, and axial transverse orbital scans in a series of patients with Graves' ophthalmopathy and have compared the images in each plane. Direct sagittal and coronal scans were obtained without image regeneration from axial transverse sections by using a wide-aperture Varian body scanner and a special accessory table. Sagittal and coronal scans can demonstrate enlargement of the superior or inferior muscles even in cases in which the medial and lateral recti are normal. Since scans performed at approximately 20 degrees to the sagittal plane are parallel to the long axis of the orbit, they demonstrate orbital anatomy better than scans in the true sagittal plane.

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This report describes some of the clinical, chromosomal and radiological findings in three unrelated patients with trisomy 8 mosaicism syndrome (T8ms), two first cousins with trisomy 8q and a patient with trisomy 8p. On the basis of the phenotypic and cytogenetic findings seen in our six patients and those noted in previous reports, we concur with Riccardi & Crandall (1978) that most physical malformations seen in T8ms are associated with trisomy for the long arm of chromosome 8.

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We performed CT scans on 24 patients with clinically typical Graves' ophthalmopathy to compare the advantages of various scanning techniques. Scans were performed before and after intravenous contrast material infusion, and the contrast-enhancement of abnormal muscles was compared with that of known orbital tumors. Images were also obtained using 5-mm and 8-mm collimators, and the diagnostic value of these collimators was compared. Sagittal and coronal scans were performed in some of the cases, using a new direct technique for the sagittal plane. In general, the 5-mm collimators provided sharper definition of the ocular muscles and optic nerves. Contrast-enhancement alone was not helpful in differentiating enlarged muscles from orbital tumors because of the great overlap of attenuation coefficients. Sagittal and coronal images were helpful in confirming muscle enlargement suspected from axial scans, and were most useful in showing enlarged superior and/or inferior recti in cases with normal medial and lateral recti. The advantages of our method of obtaining sagittal scans through the long axis of the orbit and the potential application of this technique to orbital CT scanning are discussed.

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New CT software programs allow rapid-sequence images to be obtained. During a period of 12 sec, multiple CT images can be produced, so that the progression of contrast flow at intervals of 1 sec or less can be followed. In addition, as many as 16 consecutive 3-sec scans can be performed, or arbitrary time intervals inserted between scans. The rapidity with which the contrast medium enters and leaves a specific tissue may be a valuable, non-invasive diagnostic tool in differentiating enhancing lesions. Other potential applications are mentioned.

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The clinical courses and serial computerized tomography (CT) scans of four patients with Menkes disease are described. Although the initial clinical presentations were similar, head growth and serial CT scans showed striking individual differences. The CT scans varied from showing no abnormalities early in the disease to showing diffuse cortical atrophy, subdural accumulation of fluid, or multifocal areas of ischemic infarction. The pathologic findings in one patient showed only cerebral and cerebellar atrophy, whereas the findings in another patient showed areas of ischemic infarction, probably secondary to abnormal vessels. Menkes disease should be suspected in male infants with psychomotor deterioration and seizures, or when trauma is suspected from subdural hematoma and multiple fractures.

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The temporal relationship of blood iodine levels to tumor enhancement in cranial computed tomography was studied in a series of patients. Both the bolus and biphasic techniques were evaluated. Peak tumor intensity may not develop immediately, but may be more pronounced on a 20-minute scan. The low-density centers seen in malignant gliomas show delayed enhancement. These low-density centers represent a second compartment which equilibrates with the intravascular and interstitial contrast material at a much slower rate. Patients with malignant gliomas can be scanned up to one hour following contrast injection without significant loss of information.

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A wide variety of cystic appearing or low attenuation lesions in the midline posterior fossa can so closely resemble one another as to render specific histologic diagnosis from CT scans alone fraught with error. Absorption coefficients often overlap and are too nonspecific to infer consistently accurate histologic diagnosis. It is virtually impossible to separate cystic from noncystic, benign from malignant, and neoplastic from non-neoplastic lesions by absorption coefficients alone.

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Sagittal scans of the brain and orbits can be performed with the Varian body scanner and an accessory table. These scans are obtained directly, with no image reconstruction from scans in other planes. A case of Graves' ophthalmopathy is presented which demonstrates the potential advantage of sagittal images in showing abnormalities near the orbital roof and floor. Sagittal scans complement coronal and axial views in CT evaluation of the orbits.

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Lesions of the ventricular ependyma and its derivatives can be visualized by CT scans, and their nature and extent can be determined. Generalized enhancement of the ependyma following the administration of intravenous contrast media can be seen with spendymoma, medulloblastoma, metastatic dysgerminoma, glioblastoma multiforme, and ependymitis. Localized ependymal enhancement can often be identified in the presence of acute ventriculitis, vascular anomalies or malformations, cerebral infarctions with luxury perfusion, and vascular neoplasms.

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The secondary effects of large infratentorial masses may include ascending transtentorial herniation. Rostral displacement of the superior vermis through the tentorial incisura can be accurately detected by cranial computed tomography. Signs of early or impending upward herniation are compression and slight posterior flattening of the quadrigeminal plate cistern. Progressively more severe herniation produces amputation of the peritcetal cerebrospinal fluid diamond, leading to a triangle or "squared off" appearance of the confluent quadrigeminal and superior cerebellar cisterns. When the disorder is severe, the herniated vermis plugs the incisura, completely effacing these cisterns and flattening the posterior third ventricle. Obstructive hydrocephalus may also occur with moderate or severe herniation.

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