Relative efficacy of computed tomography and radionuclide scan in the diagnosis of organic brain syndrome

Computerized tomography (CT) scan and radionuclide (Rn) scan findings on 77 psychiatric patients were compared to evaluate the relative efficacy of these two procedures in the diagnosis on intracranial disease. CT scan detected significant abnormalities in 23 patients (29.9%) while the Rn scan was positive in only five patients (6.5%). This is almost a fivefold difference in the detection rate of abnormalities between the CT and RN scan. Thirty-four of the 77 patients were diagnosed with organice brain syndrome (OBS) according to the criteria by Feighner et al. CT scan exclusively determined the contributing causes in 20 (58.8%) of these patients. In contrast, none of the Rn studies could exclusively contribute to a diagnosis of OBS. It is concluded that the routine use of both diagnostic procedures hardly seems justifiable in terms of patient benefit and increased cost.     

Functional imaging of the brain using computed tomography

Data from rapid-sequence CT scans of the same cross section, obtained following bolus injection of contrast material, were analyzed by functional imaging. The information contained in a large number of images can be compressed into one or two gray-scale images which can be evaluated both qualitatively and quantitatively. The computational techniques are described and applied to the generation of images depicting bolus transit time, arrival time, peak time, and effective width.     

Optimal utilization of computerized cranial tomography and radionuclide brain imaging

The results of computerized cranial tomography and radionuclide brain imaging in 490 patients were compared in relationship to the patients' clinical presentation. In 195 patients with focal neurologic abnormalities, both tests detected most lesions, but computerized cranial tomography was slightly more accurate overall. Results of both studies were normal in 69 percent of 295 patients with nonfocal neurologic presentations, and radionuclide imaging failed to detect lesions in only five patients with nonfocal presentations. These results suggest that radionuclide imaging can be used to accurately screen most patients with nonfocal neurologic presentations. An exception is the patient presenting with dementia, in whom computerized cranial tomography provides details of the anatomy of the ventricular cavities and cerebral cortex. This study demonstrates a continuing role of importance for radionuclide imaging in the evaluation of patients with neurologic disease and provides data to allow a rational approach to the optimum use of both techniques.     

The dobutamine stress test with thallium-201 single-photon emission computed tomography and radionuclide angiography: postinfarction study

OBJECTIVES: The purpose of this study was to investigate left ventricular wall motion changes during dobutamine-induced myocardial ischemia. BACKGROUND: Dobutamine is increasingly used as a stress test. It has been assumed that high doses of the drug induce the same changes in contractility as physical exercise. However, some data suggest that ischemic myocardium can respond to dobutamine with an increase in contractility. METHODS: Sixty-three postinfarction patients twice underwent the dobutamine test (up to 40 micrograms/kg per min) within 1 to 2 days. Thallium-201 single-photon emission computed tomography (SPECT) and gated equilibrium radionuclide ventriculography were performed on each patient at rest and with dobutamine. Both global and regional ejection fractions were quantified. Sixty patients underwent coronary cineangiography within 1 week. The presence of redistribution was correlated with global and regional ejection fraction changes and with coronary lesions. RESULTS: Redistribution was present in 45 patients, and no change or a decrease in global or regional ejection fraction was detected in 22. In the entire group of patients global ejection fraction increased from 46 +/- 12% to 56 +/- 14%. The six patients with triple-vessel disease had a flat (-0.2 +/- 5%) ejection fraction response to dobutamine, whereas the remaining patients had an increase of 11 +/- 7% (p = 0.003). The regional ejection fraction of the hypokinetic area increased from 27 +/- 10% to 41 +/- 19%, showing no change or a decrease in 13 patients. The 44 patients with peri-infarct redistribution had a significantly higher increase in regional ejection fraction than those without redistribution (16.4 +/- 10% vs. 4.7 +/- 17%, p = 0.003). In the patients with peri-infarct redistribution, an inverse linear correlation was found between redistribution score and dobutamine-induced regional ejection fraction change (r = -0.44, p = 0.004). CONCLUSIONS: Mild to moderate dobutamine-induced peri-infarct ischemia is compatible with an increase in contractility, whereas severe ischemia induces worsening of wall motion.     

Helical computed tomography for abdominal imaging

Significant technologic advances have taken place in computed tomography (CT). Current-generation conventional CT scanners are able to image a slice of tissue in as little as 2 to 3 seconds and can acquire several consecutive images. Although it is a substantial improvement from the CT of 5 years ago, there remain practical limits to the utility of conventional CT imaging within the abdomen. Recently, a new type of CT gantry design ("slip-ring") and faster computers have contributed to the development of a new generation of CT scanners, the "helical" or "spiral" CT scanners.     

Important role for angiotensin III and IV in the brain renin-angiotensin system

Children taught to sequence pairs of visual stimuli also performed additional sequences without direct training. In Experiment 1, the children were trained to produce a six-stimulus sequence (A > B > C > D > E > F) with one set of forms, and five overlapping two-stimulus sequences (A > B, B > C, C > D, D > E, and E > F) with another set of forms. Few of the children succeeded on tests for the untrained two- (e.g., B > D and B > E) and six-stimulus sequences derivable from the two-stimulus training. The children in Experiments 2 and 3 received only the overlapping sequence training before testing with refined protocols: Nearly all succeeded on tests of emergent sequences involving two, three, four, five, and six stimuli. The results suggest methods for examining transitive relations between pairs of the stimuli used in training and the development of a relation of order among all six of the stimuli involved.     

A standardized method for computed tomography of the orbits

A standardized method for the CT exploration of the orbital region has been searched for. This method makes it possible to visualize the entire orbital region with a minimum of 4 tomographic scans, each section 6 mm thick. The reference line chosen for this exploration is parallel to the optic nerve and joins the projection of the inferior border of the orbit on the lateral view with the upper border of the ear to the scalp. After each tomographic scan the patient is moved so that the new scanning line is still parallel to the reference line but distant by 9 mm from the previous one.     

Spiral computed tomography for bilioenteric anastomotic stricture

Spiral computed tomography scanning after intravenous cholangiography (IVC-SCT) was used to assess the anatomy of the biliary tree and anastomosis in a 7-year-old girl with recurrent cholangitis 5 years after surgical excision of a choledochal cyst. The technique clearly visualized the stenosis of the hepaticojejunostomy and hepatic duct and the dilated intrahepatic ducts. IVC-SCT provides a precise, prompt, and accurate image with minimal invasiveness and is especially suitable for the preoperative evaluation of pediatric patients.     

The xenon-enhanced computed tomography cerebral blood flow method

It has been proposed that one of the primary events in the development of essential hypertension is a growth-related process initiated as early as during fetal development. Differences in kidney size have been observed between most rat models of hypertension and their respective controls. In this study, we analyzed relative kidney size (kidney weight/body wt) in a set of rat recombinant inbred strains (RIS) (N = 27) and their progenitors, the spontaneously hypertensive rat strain (SHR/Ola) and Brown Norway congenic strain (BN.1x), at two different ages, at birth and at 15 weeks. In the progenitors, the relative kidney weight was higher in the hypertensive than in the normotensive strain of both the newborn (P < 0.001) and adult (P < 0.001) animals. In the RIS, a significant correlation was found between the newborn and adult relative kidney weight (r = 0.49, P = 0.01), indicating that the two phenotypes share some of their genetic determinants. A total genome search of newborn and adult relative kidney weight was performed with a total of 453 genetic markers. These analyses revealed several suggestive quantitative trait loci (QTL), some of which were, indeed, significant for both newborn and adult relative kidney weight (such as, D3Mit9 on rat chromosome 3; r = -0.50, P < 0.01; r = -0.47, P < 0.01; respectively). Others, such as the locus on rat chromosome 1 (Rt6; r = -0.43, P < 0.05), were significant only for the adult relative kidney size. This QTL was found in close proximity to a region previously related to susceptibility to hypertensive renal disease in the fawn-hooded rat and, similarly to that study, its effect was found to be independent of blood pressure. Furthermore, a growth pattern of the kidneys after birth, evaluated as the difference between the newborn and adult relative kidney weight, was also subjected to total genome scan. Several suggestive QTL were identified. One of the most significant loci was found at the D1a marker on rat chromosome 17 (r = -0.51, P < 0.01), which was previously related to the determination of adult heart weight in the RIS. In conclusion, the current study demonstrates the usefulness of RIS in studies of hypertension-related phenotypes, some of which are abnormal before the development of high blood pressure. To better understand their role in the pathogenesis of hypertension, studies at different ages are needed, which are uniquely feasible in RIS.     

The technical design and performance of ultrafast computed tomography

The ultrafast radiograph CT scanner utilizes a scanning electron beam and semicircular tungsten targets to produce a moving radiograph source about the patient, thus eliminating mechanical motion within the gantry. This design allows scan times as short as 50 or 100 ms, as well as two levels of image resolution. The short scan time reduces the effects of motion blurring and artifacts and provides the ability to obtain high-quality images of dynamic processes and rapidly moving organs. When utilized in the SS (high-resolution) mode, the UFCT scanner provides contiguous image acquisition through a patient volume at rapid speeds, yet maintains image quality comparable with conventional CT scanners. This technology provides extremely short exposure times, rapid acquisition of multiple slices, continuous scanning without concern for anode heat storage and dissipation, and the ability to image moving organs or flowing contrast media. Many clinical applications exist that exploit these unique features.     

Pulmonary embolism. The role of computed tomography angiography

NONINVASIVE PROCEDURE: Helical CT angiography is a noninvasive procedure whose only relative contraindications are renal insufficiency and iodine allergy. MASSIVE PULMONARY EMBOLISM: If a massive pulmonary embolism is suspected, helical CT angiography is the examination of choice because of its high accuracy in detecting proximal thrombi and its safety profile. NON-MASSIVE PULMONARY EMBOLISM: If a non massive pulmonary embolism is suspected, helical CT angiography, because of its high specificity, can be the first examination instead of scintigraphy. If a thrombus is depicted by CT, the diagnosis of pulmonary embolism is confirmed and treatment is started. If no thrombus is visualized by CT, pulmonary embolism can be ruled out in most cases. In case of doubt, another noninvasive procedure should be performed. Angiography should be the exception and seldom is needed.     

Correlation of computed tomography findings and serum brain damage markers following severe head injury

The objective of our study was to investigate the association between the initial levels of serum S-100B protein and neuron specific enolase and the severity of radiologically visible brain damage and outcome after severe head injury. Admission computed tomography (CT) scans of forty-four patients with severe head injury were analysed. Initial levels of S-100B protein and neuron specific enolase were compared between the different outcome groups at 6 month, the different categories of the Marshall classification, the presence of traumatic subarachnoid haemorrhage, the type of haematoma and the volume of contusion. Serum S-100B was significantly higher in patients with unfavourable outcome (1.1 micrograms/l versus 0.3 microgram/l, p < 0.005, Mann-Whitney U test). In diffuse injury, unfavourable outcome significantly increased with higher Marshall grades (p < 0.05). There was a significant correlation between the four grades of diffuse injury and initial serum S-100B protein (r = 0.48, p < 0.001). Patients with focal mass lesions and a favourable outcome after 6 month had significantly lower S-100B values than those who had an unfavourable outcome (0.51 microgram/l versus 1.3 micrograms/l, p < 0.05). A significant correlation was demonstrated between the volume of contusion visible on CT scans and serum S-100B (r = 0.58, p < 0.001). In our study, initial serum S-100B protein was a powerful predictor of outcome even within the same category of radiologically visible brain damage. Serum S-100B protein may provide independent information about the severity of primary brain damage after head injury.     

Some devices for computed tomography radiotherapy treatment planning

Some simple technical devices for radiotherapy planning using computed tomography are reported, including (a) a wide, flat-topped plywood couch, (b) a poultice patch to mark the treatment area, (c) a Plexiglas scan level marker, and (d) reference anteroposterior radiographs using a conventional X-ray TV system.     

Use of spiral computed tomography for multiplanar dental reconstruction

This was a community-based study to evaluate the prevalence and characteristics of female urinary incontinence in women aged 18 and above in the Shatin District of Hong Kong. Of a total of 1018 female households contacted, 362 individuals were successfully interviewed and 123 women (34%) reported they had experienced at least one episode of urinary incontinence as adults. Of these, 18.5% reported persistent incontinence and 15.5% reported absence of incontinence after a single episode of urine loss. The risk factors for incontinence revealed by this study were body mass index and parity. Women who had never been incontinent had a lower body mass index and were usually nulliparous. Most of the respondents (43.9%) who had urinary incontinence considered the condition to be a minor problem and did not seek professional advice. This investigation indicates that a territory-wide study should be carried out to determine the incidence of urinary incontinence throughout Hong Kong.     

Diagnosis of the abdominal vascular system by means of electron-beam computed tomography (EBT)]

Pokeweed antiviral protein (PAP) from Phytolacca americana is a highly specific N-glycosidase removing adenine residues (A4324 in 28S rRNA and A2660 in 23S rRNA) from intact ribosomes of both eukaryotes and prokaryotes. Due to the ribosome impairing activity the gene coding for mature PAP has not been expressed so far in bacteria whereas the full-length gene (coding for the mature 262 amino acids plus two signal peptides of 22 and 29 amino acids at both N- and C-termini, respectively) has been expressed in Escherichia coli. In order to determine: 1) the size of the N-terminal region of PAP which is required for toxicity to E. coli; and 2) the location of the putative enzymatic active site of PAP, 5'-terminal progressive deletion of the PAP full-length gene was carried out and the truncated forms of the gene were cloned in a vector containing a strong constitutive promoter and a consensus Shine-Dalgarno ribosome binding site. The ribosome inactivation or toxicity of the PAP is used as a phenotype characterized by the absence of E. coli colonies, while the mutation of PAP open reading frames in the small number of survived clones is used as an indicator of the toxicity to E. coli cells. Results showed that the native full-length PAP gene was highly expressed and was not toxic to E. coli cells although in vitro ribosome inactivating activity assay indicated it was active. However, all of the N-terminal truncated forms (removal of seven to 107 codons) of the PAP gene were toxic to E. coli cells and were mutated into either out of frame, early termination codon or inactive form of PAP (i.e., clone PAP delta107). Deletion of more than 123 codons restored the correct gene sequence but resulted in the loss of the antiviral and ribosome inactivating activities and by the formation of a large number of clones. These results suggest that full-length PAP (with N- and C-terminal extensions) might be an inactive form of the enzyme in vivo presumably by inclusion body formation or other unknown mechanisms and is not toxic to E. coli cells. However, it is activated by at least seven codon deletions at the N-terminus. Deletions from seven through to 107 amino acids were lethal to the cells and only mutated forms (inactive) of the gene were obtained. But deletion of more than 123 amino acids resulted in the loss of enzymatic activity and made it possible to express the correct PAP gene in E. coli. Because deletion of Tyr94 and Val95, which are involved in the binding of the target adenine base, did not abolish the activity of PAP, it is concluded that the location previously proposed for PAP enzymatic active site should be reassessed.     

-Arthrography and computed tomography arthrography of the wrist-

A five-generation family is here reported in which several members developed malignant melanoma, dysplastic naevi, astrocytoma in all grades, benign or malignant schwannoma, neurofibroma, or meningioma in a single instance. Significant cosegregation of skin and nervous tumours, preclusion of allelism to type 1 neurofibromatosis and phenotypic departure from known syndromes of hereditary proneness to cancer make one suggest an original familial predisposition to both malignant melanoma and central/peripheral nervous tumours.     

Attenuation values in computed tomography of the abdomen

Attenuation values were obtained from 50 CT examinations of the upper abdomen. A normal range of values, obtained for the organs in the upper abdomen, was compared with patient size and age. Rank ordering according to the mean attenuation values was also performed. The most significant finding was that the liver normally had the highest attenuation value of any of the viscera measured. When another organ in the upper abdomen had a mean value greater than that of the liver, this reflected severe systemic disease.     

Abnormalities of the azygo-oesophageal recess at computed tomography

The azygo-oesophageal recess is well demonstrated at CT. It may be distorted by pathologic processes in mediastinum, pleura and lung. Illustrations of the various conditions have been selected from 933 CT examinations.