Optimal contrast enhancement of the liver using helical (spiral) CT: value of SmartPrep.
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Aortography↗
Biomedical subjects
B Brown
Publications and source records attributed to B Brown.
Helical CT of the liver: clinical application of an automated computer technique, SmartPrep, for obtaining images with optimal contrast enhancement.
OBJECTIVES: The purpose of this study was to evaluate an automated computer technique (SmartPrep) for achieving a consistently high level of contrast enhancement in the liver with helical CT. The technique compensates for variability between patients by indicating graphically the time at which scanning should be initiated to reach a desired level of hepatic enhancement. MATERIALS AND METHODS: One hundred nine consecutive patients undergoing helical CT of the abdomen were randomly evaluated, using either a standard 70-sec delay from the start of the injection of contrast material to scanning or a newly developed, commercially available automated technique, SmartPrep. A series of multiple low-dose scans was performed until an arbitrary threshold of hepatic enhancement (50 H) over baseline was achieved. Three regions of interest (ROIs) were imaged on a baseline scan and on contrast-enhanced scans at the upper, mid, and lower liver. Average hepatic enhancement and the standard deviation over baseline was calculated for each group at all anatomic levels. For the SmartPrep group, the range of time between scan initiation and onset of scanning was calculated. RESULTS: The mean hepatic enhancement for the control group (n = 56) was 59.8 +/- 20.1 H, which differed significantly (p = .0002) from that for the SmartPrep group (n = 53), which was 71.6 +/- 15.2 H. Comparison of the variability between the two groups' enhancement levels was also significant (p = .02). The range of delay times for the SmartPrep group was 48-86 sec. In two additional cases, abnormal graphically displayed enhancement curves were the first indication of an improper injection. CONCLUSION: Use of SmartPrep yields a greater and more consistent level of hepatic enhancement from patient to patient than does use of a conventional fixed delay time. The ability to scan more efficiently to achieve greater hepatic enhancement using SmartPrep has significant implications for potential contrast cost savings.
Diagnosis, Computer-Assisted↗
The effect of benoxinate on the tear stability of Hong Kong-Chinese.
We conducted a series of experiments to examine the effect of local anaesthetic instillation on tear stability measurements. All experiments were conducted with the examiner masked with respect to treatments. We measured tear break-up time (TDUT) and non-invasive tear break-up time (NITBUT) 30s after instillation of benoxinate (0.4%) in a single masked experiment and found that NITBUT was significantly increased while TBUT was unaffected. In separate experiments tear stability was assessed 5 min after instillation of benoxinate and there was no significant effect on either TBUT or NITBUT measurements. In a control experiment to examine the effect of instilling a drop of liquid into the eye, neither TBUT nor NITBUT were affected 30s after the instillation of saline. No corneal staining was observed in any of the subjects after instillation of benoxinate. The results suggest that benoxinate does not affect the stability of the precorneal tear film, and that tear stability can be assessed after the instillation of unpreserved benoxinate.
Adult↗
[Clinical aspects and follow-up in dilated cardiomyopathy].
Dilative cardiomyopathy is a heterogeneous myocardial disease characterized by a depressed contractile function and ventricular dilation. The exercise intolerance of patients with dilative cardiomyopathy is partly explained by changes of metabolism and composition of skeletal muscle, whereas the physical findings result from progressive heart failure and cardiac remodeling. The clinical course of the disease is highly variable and prognostic indicators of progressive heart failure or cardiac arrhythmias are of little value in the assessment of cardiac risk in an individual patient. During recent years the mortality of patients with dilative cardiomyopathy was 5-15%, which appears to be lower than previously reported. The differences in mortality today and in previous years may be explained by a more precise and earlier diagnosis of the disease and possibly better treatment strategies. Patients with a severely depressed left ventricular function but a stable clinical course, a good hemodynamic response to therapy, and an oxygen uptake of > 12 ml/kg min can be followed without heart transplantation. It can be expected that the definition of the molecular causes of dilative cardiomyopathy will lead to a better classification of the patients and the development of more efficient treatment strategies.
Cardiomyopathy, Dilated↗
Synergy test for recognition of epitopes on soluble proteins; its application in the study of CD21 and CD23 antigens and their respective antibodies.
Antigens such as CD21 and CD23, which express only one copy of an epitope require two monoclonal antibodies (mAbs) for their detection and estimation. This requirement is exploited in two ways in a technique based on the chromic chloride haemagglutination test. For simple titration of antigen two portions of red cells each coated with one of a pair of synergising mAbs are used in a 1:1 combination. For testing the antigenic specificity of a mAb and assessing its region of epitope binding, the mAb under test is serially diluted in fluid containing a standard amount of antigen and red cells are added to which have been attached a different mAb. If the red cell-bound mAb recognises a determinant topographically distinct from that of the soluble mAb, red cell agglutination to high titre occurs. In titrations of ascitic fluid containing approximately 1 mg/ml mAb, titres of log2(9) to log2(16) were recorded from a starting dilution of 1 in 200. Hence the test is very sensitive and only minute amounts of a mAb are required for testing. The same test system can be used for assessing the relative display of epitopes on antigen obtained from different sources, e.g., culture supernates and body fluids. The method is of general applicability to monomeric antigens and its use is illustrated by analysis of CD21 and CD23 antigens and antibodies.
Animals↗
Scaling of voltage-current characteristics of thin-film Y-Ba-Cu-O at low magnetic fields.
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Journal Article↗
The use of peer evaluation in promoting nursing faculty teaching effectiveness: a review of the literature.
Many authors have recommended that peer evaluation should be a key component in evaluating nursing faculty teaching effectiveness. Despite the purported advantages of peer evaluation it remains a controversial method for faculty evaluation. In a review of the literature the success of a peer evaluation depends on faculty involvement, short but objective methods, trained observers, constructive feedback for faculty development as well as open communication and trust.
Communication↗
Protection of immunized and previously infected chimpanzees challenged with Mycoplasma pneumoniae.
Following immunization, peak geometric mean serum metabolism inhibition antibody (MIT) titres were 1:13 and 1:16 for groups of three chimpanzees each that received either the formalin-inactivated OSU-1A or experimental acellular extract vaccine, respectively. Following challenge, the mean titres for chimpanzees given the acellular vaccine peaked at 1:256 in 4 weeks and was 1:48 at 10 weeks. Chimpanzees given the OSU-1A vaccine peaked at 1:80 in 4 weeks and remained at 1:80 at 10 weeks. There was no direct correlation between the serum MIT response and the severity of disease or colonization, and thus the MIT response was not a reliable measurement of protection. The two non-immunized chimpanzees showed significant signs of disease, including cough, pharyngitis, rhinitis, fever and abnormal X-ray findings, for about 5 weeks. The chimpanzees immunized with either vaccine were less colonized and showed far less disease than non-immunized controls. Protection afforded the chimpanzees was similar to that of vaccinees in the human clinical trial given the same OSU-1A vaccine (Wenzel et al., 1977). The two previously infected chimpanzees were most protected against colonization and disease on challenge.
Animals↗
Negative bone scintigraphy with diffuse osteoblastic breast carcinoma metastases.
A patient with diffuse osteoblastic metastases from invasive lobular carcinoma of the breast is presented in whom radionuclide bone scan was negative for skeletal lesions. Skeletal metastases were documented by plain radiography, CT, MRI, and bone marrow biopsy. This case report points to the value of plain-film, CT, and MRI findings in situations of high clinical suspicion of metastatic disease despite a normal scintigraphy.
Aged↗
The repeatability of the noninvasive blue field entoptic phenomenon method for measuring macular capillary blood flow.
The speed of macular capillary blood flow can be estimated by using the blue field entoptic phenomenon. The technique uses a matching task in which the subject matches what is seen entoptically with a computer simulation of the phenomenon. In this study, we tested the repeatability of the leukocyte speed results obtained using this technique. Fourteen young subjects were tested on five different occasions. Group mean leukocyte speed did not vary significantly from one recording session to the next. However, readings for individuals varied substantially from one recording session to the next. This variability limits the usefulness of this technique for screening or monitoring macular blood flow in individuals.
Adult↗
Age and the van Herick ratio in a Chinese population.
We derived estimates of the van Herick ratio or grading in a retrospective study using a Chinese clinical population. We found that the van Herick ratio decreased with age and increased with higher degrees of myopia. A lower van Herick ratio was found to be associated with higher intraocular pressure. There are significantly more patients with lower van Herick ratios or grades in our population than in populations described by others.
Adolescent↗
Reduction in stereoacuity with age and reduced retinal illuminance.
Stereoacuity has been reported to decrease significantly in the seventh decade of life. Could this decrease be due to a reduction of retinal illuminance in the ageing eye? In this study, we used a more rigorous psychophysical procedure than that used previously, on 35 subjects, aged 21-67 years, to determine if the reported effect of age on stereoacuity could be replicated. We also compared the stereoacuity of 15 healthy young adults under normal and reduced retinal illuminance. A forced-choice algorithm was used to improve the accuracy of measurements. Results suggest that the reduced retinal illuminance resulting from normal ageing is not the cause of the decreased stereoacuity found with ageing.
Adult↗
Altered energy balance may account for growth failure in Rett syndrome.
To determine whether alterations in energy balance account for growth failure in Rett syndrome, we measured dietary energy intakes, fecal fat losses, activity patterns, and sleeping as well as quietly and actively awake metabolic rates in Rett syndrome girls and healthy controls. Dietary energy intakes and fecal fat losses did not differ between the groups. Metabolic rates while sleeping and quietly awake were 23% lower (P < .05) in Rett syndrome girls than in controls; metabolic rates while actively awake did not differ between the groups. However, because of the 2.4-fold greater time (P < .001) spent in involuntary motor movement, energy expenditure associated with activity was twofold greater (P < .05) in Rett syndrome girls than in controls. Although total daily energy expenditure of the two groups did not differ significantly, energy balance was less positive in the Rett syndrome girls than in the controls. This small difference in energy balance, if sustained over months to years, is sufficient to account for growth failure in Rett syndrome girls.
Anthropometry↗
The natural history of familial cavernous malformations: results of an ongoing study.
Cavernous malformations are congenital abnormalities of the cerebral vessels that affect 0.5% to 0.7% of the population. They occur in two forms: a sporadic form characterized by isolated lesions, and a familial form characterized by multiple lesions with an autosomal dominant mode of inheritance. The management of patients with cavernous malformations, particularly those with the familial form of the disease, remains a challenge because little is known regarding the natural history. The authors report the results of an ongoing study in which six families afflicted by familial cavernous malformations have been prospectively followed with serial interviews, physical examinations, and magnetic resonance (MR) imaging at 6- to 12-month intervals. A total of 59 members of these six families were screened for protocol enrollment; 31 (53%) had MR evidence of familial cavernous malformations. Nineteen (61%) of these 31 patients were symptomatic, with seizures in 12 (39%), recurrent headaches in 16 (52%), focal sensory/motor deficits in three (10%), and visual field deficits in two (6%). Twenty-one of these 31 patients underwent at least two serial clinical and MR imaging examinations. A total of 128 individual cavernous malformations (mean 6.5 +/- 3.8 lesions/patient) were identified and followed radiographically. During a mean follow-up period of 2.2 years (range 1 to 5.5 years), serial MR images demonstrated 17 new lesions in six (29%) of the 21 patients; 13 lesions (10%) showed changes in signal characteristics, and five lesions (3.9%) changed significantly in size. The incidence of symptomatic hemorrhage was 1.1% per lesion per year. The results of this study demonstrate that the familial form of cavernous malformations is a dynamic disease; serial MR images revealed changes in the number, size, and imaging characteristics of lesions consistent with acute or resolving hemorrhage. It is believed that the de novo development of new lesions in this disease has not been previously reported. These findings suggest that patients with familial cavernous malformations require careful follow-up monitoring, and that significant changes in neurological symptoms warrant repeat MR imaging. Surgery should be considered only for lesions that produce repetitive or progressive symptoms. Prophylactic resection of asymptomatic lesions does not appear to be indicated.
Adolescent↗
Therapy-related leukemia and myelodysplastic syndrome in chronic lymphocytic leukemia.
A retrospective analysis was performed to determine the incidence and clinical features of acute myelogenous leukemia/myelodysplastic syndrome (AML/MDS) developing in chronic lymphocytic leukemia (CLL) patients. AML/MDS occurred in 3/1374 CLL patients seen at a single institution between 1972 and 1992. The median follow-up exceeded 7 years and 72% of these patients had received prior alkylating agent therapy. The expected number of AML/MDS developing in a general population of the same size was 1.2 as calculated from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program data (observed-to-expected ratio = 2.49; 95% confidence interval = 0.9-7.3; p = 0.12). Although, not included in the incidence calculation, four patients with CLL were referred at the time of development of AML/MDS. CLL and AML/MDS were diagnosed concurrently in two patients. Three of the patients had received no prior alkylating agents. The median survival was 17 months in patients who had received no prior treatment, and 5 months in those who had received prior chemotherapy. Our results suggest that patients with CLL in whom AML/MDS develops have similar prognoses to other patients with AML/MDS. Furthermore, this analysis does not provide evidence for a heightened risk of AML/MDS in CLL patients, despite treatment with known leukemogenic agents.
Aged↗
Squamosal suture of cranium KNM-WT 17000.
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Animals↗
New Australopithecus boisei calvaria from East Lake Turkana, Kenya.
The calvaria of an adult Australopithecus boisei from Area 104, Koobi Fora, Lake Turkana, is described. The specimen, KNM-ER 23000, comes from sediments dated to about 1.9 Ma. It consists of the frontal, both parietals, both temporals, most of the occipital as well as two small pieces of sphenoid, and a mandibular tooth root. The specimen is presumed to be an adult male, based on its size and the great development of features associated with the masticatory apparatus. KNM-ER 23000 is close in general size and shape to KNM-ER 406, KNM-ER 13750, and Olduvai Hominid 5 and it has a mixture of features seen in these three roughly contemporaneous crania. The frontal, especially the tori, resembles that of OH 5; the parietals are most like those of KNM-ER 13750; the occipital is like those of the two other Turkana specimens, and the temporals have a mixture of features from all of these, This specimen adds to our knowledge of variability in A. boisei.
Adult↗
Experimentally induced Mycoplasma pneumoniae pneumonia in chimpanzees.
Eight chimpanzees were examined. Two served as negative control and six inoculated with Mycoplasma pneumoniae became colonized. Colonization persisted for 28-68, 16-50 and 21 days with an average duration of 47, 32.5 and 21 days in the oropharyngeal, tracheal and lung tissues, respectively. Mycoplasma titers ranged from 10(8) to 10(1) color-changing units per specimen during the course of the infections. Seroconversion occurred within 12-15 days and peak antibody titers ranged from 1.256 to 1.1024 and developed between days 28 and 48 post-inoculation. Positive cold agglutinin titers were detected between 12 to 15 days and peak titers ranged from 1:80 to 1:640. Significant increases in sIgA and IgG immunoglobulin antibody levels were detected in lung lavage fluids. Unlike the many other experimentally infected animals examined, chimpanzees infected with M. pneumoniae had positive X-ray findings, developed cold agglutinins and showed overt signs of disease. These signs include persistent cough, low grade fever, rhinitis, oropharyngitis, diarrhea, and loss of appetite. Peak severity of disease corresponded with peak lung colonization, and the detection of cold agglutinins and positive X-ray findings. The microbiological, serological and clinical aspects of pneumonia induced in chimpanzees was similar to naturally occurring primary atypical pneumonia in humans.
Agglutinins↗