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Biomedical subjects

B Jung

Publications and source records attributed to B Jung.

157 records · Page 9Linked to original sources
PubMedDate not supplied

Structure enhancement by subtraction in magnetic resonance imaging.

Two patients with tumours in the pituitary gland and the liver, respectively, were studied with MRI. Regions of different transverse relaxation times were found in the tumours. Subtraction of images recorded with different echo times demonstrated the tumour regions better than the original images although these were recorded with 2 repetition times and double and multiple echo sequences. Subtraction techniques may thus aid diagnosis in MRI.

Adenoma, Islet Cell↗
PubMedDate not supplied

Technical aspects of magnetic resonance imaging in parathyroid gland lesions.

Two patients with primary hyperparathyroidism were examined before parathyroid surgery with magnetic resonance imaging at 0.35 tesla in order to analyse optimal methods of visualization. Two large parathyroid glands in the neck had long transverse relaxation times which rendered them clearly visible in T2-weighted images as structures of a signal intensity higher than that of the surrounding. Large parathyroid lesions may thus be easily detected by magnetic resonance imaging provided proper examination parameters are employed.

Adult↗
PubMedDate not supplied

Computed chest tomography in rats with pulmonary damage due to microembolism.

Computed chest tomography was performed in 13 rats with pulmonary damage due to microembolism, caused by injection of thrombin (500 NIH/kg body weight) and tranexamic acid, a fibrinolytic inhibitor (200 mg/kg body weight), and in 9 control rats. The purpose of the investigation was to perform attenuation measurements at two levels of the right lung, each with three regions of interest (anterior, mid and posterior). Alterations in attenuation, compared with controls, were correlated with lung weight. Compared with controls, the attenuation was significantly increased in the anterior and posterior regions at both levels in animals with pulmonary damage, but not in the mid regions. There was a statistically significant correlation between increasing attenuation and increasing lung weight. A significant difference was found between damaged and control lungs regarding the microscopic grade of interstitial oedema, alveolar oedema and fibrin. Histograms of attenuation values in computed tomograms might be of value in detecting alveolar oedema. It is concluded that computed chest tomography is a good method for detecting pulmonary oedema at an early stage of experimental microembolism in the rat.

Animals↗
PubMedDate not supplied

Comparative measurements of the mucosal blood flow in the human maxillary sinus by plethysmography and by xenon.

Two different methods, one plethysmographic and one where the elimination of radioactive inert gas was measured, have been used to calculate the blood flow in the mucosa of the maxillary sinus in living man. A total of 5 persons were investigated and the mean values of the blood flow in the two methods showed a close correlation. Plethysmography is more easily performed and is therefore the preferable method to be used in studies on the physiology of the maxillary sinus.

Adult↗
PubMedDate not supplied

Attitudes of Canadian nephrologists toward dialysis modality selection.

OBJECTIVE: To determine the opinions and attitudes of Canadian nephrologists about dialysis modality decisions and optimal dialysis system design. PARTICIPANTS: Members of the Canadian Society of Nephrology. INTERVENTION: A mailed survey questionnaire. RESULTS: A 66% response rate was obtained. Decisions about modality are reported to be based most strongly on patient preference (4.4 on a scale from 1 to 5), followed by quality of life (4.06), morbidity (3.97), mortality (3.85), and rehabilitation (3.69), while neither facility (1.78) nor physician (1.62) reimbursement are important. When asked about the current relative utilization of each modality, nephrologists felt that hospital-based hemodialysis (HD) is slightly overutilized (2.53), continuous ambulatory peritoneal dialysis (CAPD) is about right (3.00), while cycler peritoneal dialysis (PD) (3.53), community-based full (3.83) and self-care HD (3.91), and home HD (4.02) are underutilized. A hypothetical question about optimal distribution to maximize survival revealed that a type of HD should constitute 62.8% of the mix, with more emphasis on cycler PD (14.9%), community-based full care HD (13.8%), self-care HD (14.5%), and home HD (9.0%) than is current practice. However, when the goal was to maximize cost effectiveness, HD fell slightly to 57.8%. CONCLUSIONS: These survey results suggest that the current national average 66%/34% HD/PD ratio is reasonable. However, there appears to be a consensus that Canada could evolve to a more cost-effective, community-based dialysis system without compromising patient outcomes.

Attitude of Health Personnel↗
PubMedDate not supplied

[Measurement of transport in mucous membrane in the human nose with Cr-51-labeled resin beads].

The mucociliary transport of the human nasal mucosa was studied by using very small resin beads tagged with 51Cr. Several modifications of previous methods were introduced, e.g. kind of nuclide, particle size, pH, mode of application, measuring technique and reduction of local irradiation. Finally arrangements implying exact measurements of transport not only horizontally but also vertically or obliquely were obtained. No mucociliary transport was demonstrated in five of nine subjects with a common cold 10 days before or one week after the investigation. Xylometazolin as a nasal spray diminished the mucociliary transport significantly. In addition, the effects on mucociliary transport caused by homolateral or contralateral experimental nasal obstruction as well as by tobacco smoking were studied in healthy subjects. Finally, patients with various diseases: pollen allergy in free intervals, chronic rhinitis, septal deviation or perforation, and condition after laryngectomy were also investigated.

Adult↗
PubMedDate not supplied

Magnetic resonance imaging in primary amyloidosis.

Twelve patients with primary amyloidosis (AL) were investigated with magnetic resonance imaging (MRI). In 9 patients an abnormal thickening of the heart walls was present and in 2 macroglossia was found at MRI. T1 was significantly increased in liver (p less than 0.05) and subcutaneous fat (p less than 0.01) while it was decreased in the spleen (p less than 0.05). T2 was significantly decreased (p less than 0.01) in the spleen in patients with amyloidosis, while it was not significantly altered in the liver or subcutaneous fat. After therapy T1 of the liver was reduced towards normal values in 4 patients. It is concluded that MRI might be a method to quantitate the amount of amyloid deposits in the tissue, and that the effect of therapy may be monitored with this technique.

Aged↗
PubMedDate not supplied

Magnetic resonance imaging for assessment of treatment effects in mediastinal Hodgkin's disease.

Six patients with mediastinal involvement of Hodgkin's disease were examined with magnetic resonance imaging (MRI) at 0.35 T before and/or at various stages of therapy, with the sequences TR/TE: 500/35, 500/70, 1600/35 and 1,600/70. Before therapy the image intensity of tumour involved lymph nodes deviated considerably from fat and muscle, but no clear difference was discerned between histopathologic subtypes or tumour localizations. After efficient therapy, the tumour image intensities and relaxation rates approached those of muscle and fibrous tissue, but remained at pre-therapy values when the patient was not in full remission. A similar pattern was found in a 'normal-tissue'--'tumour' plot, based on vector analysis of the original sets of 4 images. It is concluded that persistent tumour involvement in the mediastinum may be distinguished from fibrosis and that MRI may thus be of value in the follow-up of patients with Hodgkin's disease.

Adolescent↗
PubMedDate not supplied

Magnetic resonance imaging in diffuse malignant bone marrow diseases.

Twenty-four patients with malignant bone marrow involvement or polycythemia vera, 8 patients with reactive bone marrow and 7 healthy individuals were examined with spin-echo magnetic resonance imaging at 0.35 T and 0.5 T. Signs of an increased longitudinal relaxation time, T1, were found when normal bone marrow was replaced by malignant cells, polycythemia vera or reactive marrow. A shortened T1 was indicated in 4 patients in bone marrow regions treated by radiation therapy; the marrow was most likely hypocellular in these cases. The estimated T1 relaxation times were highly correlated to the cellularity of the bone marrow as assessed by histology. Among patients with close to 100 per cent cellularity neither T1 nor T2 discriminated between the various malignancies or between malignant and reactive, non-malignant bone marrow. Characterization of tissues in terms of normalized image intensities was also attempted, the motive being to avoid approximations and uncertainties in the assessment of T1 and T2. The normalization was carried out with respect to the image of highest intensity, i.e. the proton density weighted image. The results were in agreement with those for T1 and T2. It was concluded that MRI is valuable for assessing bone marrow cellularity, but not for differentiating between various bone marrow disorders having a similar degree of cellularity.

Adipose Tissue↗
PubMedDate not supplied

Magnetic resonance imaging with maximum contrast between two selected tissues composed of recordings with three repetition times.

A method is presented which in a composed image maximizes the image intensity difference between two selected tissues. The composition is made from several magnetic resonance (MR) images from the same slice but with different MR imaging parameters. The method is illustrated with a patient with liver metastases for whom the technique was used to emphasize metastases above normal liver parenchyma.

Carcinoid Tumor↗
PubMedDate not supplied

Effect of interferon on T1 relaxation times of liver metastases from endocrine gastrointestinal tumours.

Eight patients with liver metastases from endocrine gastrointestinal tumours were examined with magnetic resonance imaging of the liver before and during treatment with interferon. T1, T2 and tumour size were measured and compared with tumour marker levels and symptomatic improvement or deterioration. Before therapy all tumours showed a long T1 and T2, in comparison to normal liver and fat, and during therapy they all showed a decrease in T1. As no change in liver T1 and fat T1 occurred, the decreased tumour T1 is considered to be a therapy effect. This cannot be fully explained but is possibly due to a reduction in tumour growth rate during interferon treatment. There was no certain correlation between tumour T1 and tumour marker levels or symptomatic changes.

Carcinoid Tumor↗
PubMedDate not supplied

Dual energy computed tomography: simulated monoenergetic and material-selective imaging.

A dual beam-quality technique was used to reduce the beam hardening artifact in CT and to obtain separate images of osseous and soft-tissue structures in phantom and clinical CT studies. Recordings were made with pulsed low and high kVp spectra with the Somatom DR2. Conventional polyenergetic and simulated monoenergetic images were reconstructed from the measurements. In the monoenergetic images the beam hardening artifacts were 60-90% lower than in the high kVp polyenergetic images whereas the noise was of the same order of magnitude in the two types. Noise in the monoenergetic images was lowest around 70-80 keV both in body and skull examinations although the contrast in the monoenergetic image was rather independent of energy.

Giant Cell Tumors↗