The 1979 Nobel prize in physiology or medicine.
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History, 20th Century↗
Biomedical subjects
G Di Chiro
Publications and source records attributed to G Di Chiro.
Hypothalamic-pituitary dysfunction following CNS prophylaxis in acute lymphocytic leukemia: correlation with CT scan abnormalities.
In an attempt to identify possible adverse effects of CNS prophylaxis (cranial radiation and intrathecal chemotherapy), we examined hypothalamic-pituitary function in 23 patients with acute lymphocytic leukemia (ALL). Of 18 patients who had received both cranial radiation and intrathecal chemotherapy, nine had abnormally low growth hormone responses to insulin-induced hypoglycemia (less than 7.0 ng/ml). Seven of the nine patients with abnormally low growth hormone responses also manifested ventricular dilatation on computed tomography (CT) brain scans, whereas only one of the nine patients with normal growth hormone responses demonstrated this CT scan finding (P = 0.015). The remaining patients, who had not received cranial radiation, had normal growth hormone responses and normal CT scans. There is significant correlation between ventricular dilatation on CT and abnormally low peak growth hormone responses following CNS prophylaxis in ALL.
Adolescent↗
Mesial temporal sclerosis detected by computed tomography.
We report a case of an epileptic patient in whom unilateral mesial temperal sclerosis was detected by computed tomography in the form of an arcuate, nonenhancing calcification. Temporal lobectomy was followed by relief of the seizures.
Adult↗
Computed tomography profiles of periventricular hypodensity in hydrocephalus and leukoencephalopathy.
Profiles of hypodense periventricular white matter, drawn from the interior of the frontal horns through the surrounding white matter to the peripheral gray matter, were analyzed in 65 patients. Abnormal curves were grouped into four patterns: linear, double-slope, plateau, and bimodal. The first two, found primarily in hydrocephalic patients, appear to be due to transependymal passage of cerebrospinal fluid (CSF). The linear pattern was found more frequently in acute cases and indicates breakdown of the ventricular wall as a barrier. The double-slope pattern probably indicates a persistent or restored barrier effect at the wall, with residual CSF infiltration of the parenchyma. Most of the other patients' curves showed either a plateau pattern or (especially in primary leukoencephalopathy) a bimodal ("bumpy") pattern which is believed to correspond to the nonuniform nature of the pathological process.
Cerebral Ventriculography↗
Computed tomography in a verified case of tuberculous meningitis.
In a verified case of tuberculous meningitis, postcontrast computed tomograms demonstrated enhancement of the area corresponding to the cistern surrounding the brainstem. This enhancement disappeared after successful drug treatment of the meningitis.
Adult↗
Paraplegia due to posttraumatic pelvic arteriovenous fistula treated by surgery and embolization. Case report.
A case is presented in which a posttraumatic pelvic arteriovenous fistula caused progressive paraplegia because of voluminous shunting into the epidural venous system. Surgical ligation and transcatheter embolization of major and minor arterial feeders decreased shunt flow sufficiently to permit direct embolization of the fistula by an injectable plastic. This combined approach may allow obliteration of unresectable acquired or congenital arteriovenous malformations.
Adult↗
Abnormal CT scans of the brain in asymptomatic children with acute lymphocytic leukemia after prophylactic treatment of the central nervous system with radiation and intrathecal chemotherapy.
Thirty-two asymptomatic patients with acute lymphocytic leukemia, who had received prophylactic cranial radiation (2400 rads) and either intrathecal methotrexate or cytosine arabinoside were studied by computed tomography of the brain 19 to 67 months after initiation of prophylaxis. Seventeen of 32 (53 per cent) had one or more abnormal findings. Dilatation of the ventricles (eight patients) and widening of the subarachnoid spaces (nine patients) were equally distributed among patients in both intrathecal-chemotherapy groups. Areas of decreased attenuation coefficient (hypodense, abnormally radiolucent regions) (four patients) and intracerebral calcification (one patient)--lesions previously described in methotrexate leukoencephalopathy--were found only in those who had received intrathecal methotrexate. Mild central-nervous-system dysfunction was detected in seven patients but did not correlate with the presence of tomographic abnormalities. Nevertheless, these tomographic findings may represent preclinical lesions. The unexpectedly high prevalence of such abnormalities contrasts with the essentially normal tomographic findings in a control group with acute lymphocytic leukemia who received no central-nervous-system prophylaxis. These results suggest that alternative approaches to such prophylaxis be considered.
Adolescent↗
Leukoencephalopathy in oculocraniosomatic neuromuscular disease with ragged-red fibers. Mitochondrial abnormalities demonstrated by computerized tomography.
In a group of 13 patients affected by oculocraniosomatic neuromuscular disease with mitochondrial abnormalities and ragged-red fibers, a major, diffuse leukoencephalopathic process was recognized by computerized tomography (CT) in three cases. Clinically, these three patients were the most severely affected. The areas involved by the leukoencephalopathic process did not show enhancement after contrast medium injection. In several of the remaining ten cases, various forms and grades of CSF cavity dilation were encountered. Four of the 13 patients had very high CSF protein levels, three had CT-demonstrated leukoencephalopathy, and the fourth had substantial sulcal dilation. The CT findings in this group of patients corresponded well to the previously reported histopathological observations and indicated the clinical usefulness of CT in identifying brain involvement in this syndrome.
Adolescent↗
Orbital dermoid diagnosed by computed tomographic scanning.
In a 20-year-old man, computed tomography revealed that an orbital mass in the region of the lacrimal gland fossa had low density attenuation values (below water), indicating a fat-containing tumor. At surgery, we found a dermoid cyst of the oil cyst type.
Adult↗
Periventricular leukomalacia related to neonatal anoxia: recognition by computed tomography.
Periventricular areas of decreased attenuation coefficient were demonstrated by computed tomography (CT) in two infants with neurological involvement after episodes of neonatal hypoxia. This CT finding is related to anoxic periventricular leukomalacia, which is well documented in the literature. Follow-up CT scans in our two patients demonstrated reversibility of the white matter changes.
Brain Diseases↗
Transient, severe periventricular hypodensity after leukemic prophylaxis with cranial irradiation and intrathecal methotrexate.
Serial computed tomography (CT) demonstrated complete resolution of severe periventricular hypodensity occurring in a child after receiving prophylaxis for acute lymphocytic leukemia. The resolution of this encephalopathy suggests that early changes of subacute necrotizing leukoencephalopathy are reversible and CT is copable of detecting these early changes.
Acute Disease↗
Split-detector computed tomography: a preliminary report.
A split-detector system, consisting of a thin CaF2 scintillator followed by a thick Nal crystal, was installed in an EMI Mark I scanner. Energy discrimination is possible because the CaF2 crystal responds primarily to low-energy photons; dual-energy images can be obtained from only one scan. Calculations and preliminary experiments show that the split-detector separates energies better than the 100-140 kVp method. It was possibel with the split detector to differentiate between two weak solutions of CaCl2 and Kl which had the same computed tomography number (44 H), under normal scanning conditions.
Tomography, X-Ray Computed↗
Effect of CT noise on detectability of test objects.
Three types of test objects were superimposed on noisy backgrounds and observed by 58 subjects: large low-contrast disks to simulate tumors, small disks to simulate calcifications, and bars to simulate blood vessels. Three types of noise were used: random noise, CT noise (reconstructed random noise), and an actual water scan taken with an EMI CT1010 scanner. In addition, each image was smoothed by a factor of two, giving six test patterns altogether. Photographic images were presented to 25 lay observers, while 25 other lay observers and eight radiologists used a viewing console. The photographs produced a slightly lower true positive rate than the console, although the degree of confidence in the identifications was slightly greater. The anticorrelation property of CT noise gives it a "lumpy" structure, which aided the identification of bars but impeded the identification of small disks. Smoothing did not significantly affect the detectability with random noise, but with CT noise, smoothing improved the detectability of bars and large disks.
Humans↗
The apical artifact: elevated attenuation values toward the apex of the skull.
An artifact that can cause an elevation in CT numbers of as much as 20 Hounsfield units toward the apex of the head is described. This artifact was first noted on the EMI CT1010 scanner but has been observed in other scanners as well. Phantom studies of this artifact have revealed that its primary origin is the beam hardening distortion due to the large amount of bone present in apical cuts. This has been verified by computer simulations. An intuitive explanation of the origin of the artifact is also presented.
Humans↗
Leukoencephalopathy following chemotherapy for rhabdomyosarcoma: reversibility of cerebral changes demonstrated by computed tomography.
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Antineoplastic Agents↗
Computer assisted tomography in methotrexate encephalopathy.
Five children with acute lymphocytic leukemia (ALL) developed encephalopathy following treatment with intrathecal or intraventricular methotrexate (MTX). In these patients computer assisted tomography was informative by revealing areas of decreased attenuation coefficient located periventricularly and in each centrum semiovale (three cases) and calcifications, mostly in the deep and cortical gray matter (two cases), as well as ventricular dilatation (four cases). Contrast injection used in one of these five patients, as well as in another child (not affected by ALL) with MTX encephalopathy, failed to reveal enhancement.
Acute Disease↗
Computer assisted tomography in adrenoleukodystrophy.
Our findings on computer assisted tomography of the brain in four cases of adrenoleukodystrophy are sufficiently consistent to warrant delineation. Early changes, which may predate obvious clinical findings, are represented by areas of decreased attenuation coefficient in the posterior (parieto-occipital) white matter around the trigonum of each lateral ventricle. Subsequently the temporal, parietal, and frontal lobes are involved, and the extensive areas of decreased attenuation coefficient in the white matter become almost indistinguishable from the conspicuously enlarged ventricles. Only a thin ependymal wall separates the ventricular cavities from the leukomalacia lesions. Contrast medium enhancement at the periphery of the affected regions is an important, although inconsistent, feature.
Adolescent↗
White-gray matter differentiation in computed tomography.
A numerical analysis has been performed on six regions of interest within the brain for a total of 60 patients. Three areas of white matter and three of gray matter were included. A difference of 7.1 +/- 1.3 Hounsfeld units (HU: 1,000 scale) was found between white and gray matter. For eight patients who were under 15 years of age, the difference was 5.1 +/- 0.6 HU. Contrast injection resulted in a general increase of values, with gray matter showing a greater elevation by 0.5 HU. The numerical evaluation of white and gray matter has proven to be useful in the diagnosis of leukoencephalopathy.
Adolescent↗