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Biomedical subjects

A Kiuru

Publications and source records attributed to A Kiuru.

36 records · Page 2Linked to original sources
PubMed1990

Dynamic imaging of pulmonary ventilation in children using digital subtraction radiography.

Digital subtraction radiography is a sensitive method for imaging changes in pulmonary aeration during the respiratory cycle. The findings of 75 consecutive dynamic pulmonary examinations performed on 49 pediatric patients using this technique were reviewed together with the findings at chest radiography and, in 18 cases, with bronchoscopy. Symmetric diaphragmatic movement and synchronous, homogeneous variation in the attenuation of lung parenchyma indicated normal conditions in 9 (18%) patients. The most common abnormal finding (36 patients) was an asynchronous variation in the attenuation of the lung parenchyma. A greatly diminished or absent variation in attenuation was diagnostic for a serious air passage obstruction in 7 children. Other abnormal findings were a lowered amplitude of diaphragmatic movement, asynchronous diaphragmatic movement and mediastinal shift. In 10 patients (20%) the dynamic study showed parenchymal abnormalities when chest radiography was normal. Bronchoscopy was performed in 4 of these 10 patients and showed abnormalities in each case.

Adolescent↗
PubMed1989

Acute bronchial obstruction: an experimental rabbit model study.

An animal model of bronchial obstruction was developed to radiologically follow up the development of postobstructive pulmonary changes. The study material consisted of 21 healthy rabbits (New Zealand White) of which 5 animals served as controls. A piece of Surgicel (Ethicon) shaped as a 3 x 3 x 10 mm cylinder was placed endobronchially through a 3-mm bronchoscope. The animals were followed up radiologically and endoscopically during the first 30 min after which the bronchoscope was extracted. Sixteen animals were followed up for at least 4 h and, in 4 animals, the foreign body (FB) was removed after 24 h. During follow-up, total collapse of the lung was observed after 1-4 h in all but 2 animals with obstruction of the main brochus. After extraction of the FB, atelectasis of the respective lung had resolved within 24 h. The animal model developed in the present study seems to be rather physiological resembling the development of pulmonary atelectasis in pediatric patients.

Airway Obstruction↗
PubMed1989

The molecular basis for Duchenne versus Becker muscular dystrophy: correlation of severity with type of deletion.

About 60% of both Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) is due to deletions of the dystrophin gene. For cases with a deletion mutation, the "reading frame" hypothesis predicts that BMD patients produce a semifunctional, internally deleted dystrophin protein, whereas DMD patients produce a severely truncated protein that would be unstable. To test the validity of this theory, we analyzed 258 independent deletions at the DMD/BMD locus. The correlation between phenotype and type of deletion mutation is in agreement with the "reading frame" theory in 92% of cases and is of diagnostic and prognostic significance. The distribution and frequency of deletions spanning the entire locus suggests that many "in-frame" deletions of the dystrophin gene are not detected because the individuals bearing them are either asymptomatic or exhibit non-DMD/non-BMD clinical features.

Adolescent↗
PubMed1989

Gene deletions in X-linked muscular dystrophy.

Of the approximately 170 families with X-linked muscular dystrophy of the Duchenne (DMD) and Becker (BMD) type in Finland, we have studied 90 unrelated patients for intragenic deletions by using the cDNA probes described by Koenig et al. Forty-five patients (50%) had molecular deletions of one or several of the 65 exon-containing HindIII fragments. In six deletion cases junction fragments of altered size were seen. Thirty-eight (84%) of the 45 deletions were detected using only two (1-2a and 8) of the six cDNA subclones. Using a wheelchair age of 12 years to distinguish between DMD and BMD, we found that the proportions of patients with deletions were similar. Deletions were equally common in familial and sporadic disease. BMD was more commonly caused by deletions in the 5' end of the gene than was DMD. In at least three instances deletions of similar type resulted in diseases of similar severity. Of 14 patients with mental retardation seven had deletions; six of these comprised exons contained in probe 8. We conclude that cDNA hybridization studies provide a powerful diagnostic tool in DMD and BMD and that they promise to produce better insights into molecular-clinical correlations.

Chromosome Deletion↗
PubMed1987

Organ and tumor distribution of (18F)-2-fluoro-2-deoxy-D-glucose in fasting and non-fasting rats.

Differences in the uptake of (18F)-2-fluoro-2-deoxy-D-glucose ((18F)FDG) in various normal organs and the Rous sarcoma of fasted and unfasted rats were studied at 5, 15, 30, 60, and 120 minutes after i.v. injection. The uptake of (18F)FDG in the tumor, spleen, and testis increased for 120 minutes, while uptake in the other organs was either level (brain, heart, white fat) or cleared off. The uptake was higher in the tumor than in the normal organs. The fraction of viable tumor tissue as measured morphometrically correlated intraindividually with the uptake of (18F)FDG--an increase of 1% of vital tumor corresponded to a 1.01-fold increase in tumor uptake of (18F)FDG. The nutritional state was of importance for the uptake of (18F)FDG into the heart, testis and brown fat. (18F)FDG is taken quantitatively up by the viable parts of the Rous tumor; this may make it possible to follow the response of treatment in individual tumors also in man with (18F)FDG and positron emission tomography (PET).

Animals↗
PubMed1984

Early detection of developing osteoarthritis by scintigraphy: an experimental study on rabbits.

Bone scintigraphy (99mTc-MDP) was used to study the development of experimental osteoarthritis produced by extension immobilization in rabbit knees. The purpose of the study was to determine a repeatable and noninvasive method for following the joint reaction leading to osteoarthritis. In comparison with the contralateral joints activity uptake in immobilized joints was already detectable in bone scintigraphy at 24 h, at the same time as the earliest changes in the biochemical reactions of joint tissues can be detected.

Animals↗
PubMed1984

Imaging of canine cancers with 18F-2-fluoro-2-deoxy-D-glucose (FDG) suggests further applications for cancer imaging in man.

18F-2-fluoro-2-deoxy-D-glucose (FDG) is a novel radiopharmaceutical that has gained much interest as a cancer-seeking agent. In this paper two cases of histologically verified canine cancer, an osteosarcoma and a mammary carcinoma, are presented. After an intravenous bolus injection of FDG, accumulation of radioactivity over the neoplastic lesion was followed with a computer-guided specially collimated gamma camera. Ratios of radioactivity between tumour and control areas at 30 min were 2.8 and 2.2 for the osteosarcoma and the mammary carcinoma, respectively. In the osteosarcoma, which was imaged for 3 h, this ratio remained essentially stable. It is reasonable to assume that FDG will be suitable for cancer imaging in man.

Animals↗
PubMed1983

Double-contrast examination of the stomach: 100mm fluorography vs. full-size radiography.

Full-size radiographs and 100mm fluorographic spot views taken with an image intensifier were compared during double-contrast examination of the stomach. Differences in image quality between the two modalities were small; there was also a small decrease in absorbed dose, since fluoroscopy comprised more than half of the total dose. The authors recommend that 100mm spot views be used routinely in double-contrast examination of the stomach.

Contrast Media↗
PubMed1981

Measurement of pulmonary perfusion using a digitised ECG-triggered gamma ray absorption technique.

AN ECG-triggered multisweep method for the collection of low-energy gamma ray absorption data in normal and cancerous tissue has been developed, resulting in digital perfusion curves with reliable statistics. The small intensity modulation ( approximately equal to 1.2%) due to lung perfusion is detected and separated from the much stronger intensity variations caused by ventilation in a satisfactory way. During this non-invasive test the patient is supine and breathes smoothly.

Americium↗
PubMed1980

111In-bleomycin imaging of breast tumours.

Forty female patients with 15 malignant breast tumours and 25 benign growths, all verified histologically, were studied before surgery using mammography and 111In-Bleomycin scintigraphy. The patient was studied lying prone on a table with an opening so that one breast could hang in front of the gamma camera. The true positive and negative scintigraphy results are slightly poorer (70%) than the mammography results (80%) and there are more false negative scintigraphy interpretations mostly in small lesions.

Adult↗
PubMed1977

Use of a generalized modular data handling system in nuclear medicine.

Addition of a CAMAC modular data handling system to a small computer used for gamma-camera work has allowed the acquisition and processing of a broad variety of nuclear medicine data. Significant contributions have been made ranging from clinical renal evaluation to radiopharmaceutical development. Digital rectilinear scanning and computer acquisition of physiological signals such as the electrocardiogram are other applications. The system provides an inexpensive means of matching present-day nuclear computers to the diversity of data.

Computers↗
PubMedDate not supplied

Finnish PACS project.

A Finnish PACS project has been set up with the participation and financing of 13 university and central hospitals, the Medical Board of Finland, the Hospital League of Finland, the Post and Teleoffice of Finland and the Helsinki Telephone Company with the Medical Engineering Laboratory of the Technical Research Centre of Finland as the principal investigator. The project started in December 1988 and ended in December 1990. The project focused on the functional needs for PACS. The image production, archive sizes, network capacity and workstation requirements have been studied in a big university hospital. The results show that without compression the image archive size needs to be at least 10 TB. The network capacity requirement depends very much on the interactivity requirements. In normal situations less than 1 Mbit/s is needed, if the network is configured in an efficient way. In some cases, however, the speed requirement can be of the order of 100 Mbit/s. A proposal for a hospital-wide PACS network was made. Simple calculation rules to estimate the needed capacities were also developed.

Computer Systems↗
PubMedDate not supplied

Mailed TL dosimeters for monitoring the output from diagnostic x-ray equipment.

Mailing thermoluminescent (TL) dosimeters for exposure to users of diagnostic x-ray equipment is a simple and inexpensive way of monitoring output from x-ray units. The readings given by TL dosimeters were originally compared with ionization chamber measurements and shown to give reliable and compatible results. Mailed TL dosimeters alone were later used in a university hospital to check the functioning of exposure timers in thorax and Bucky stands. A thorough survey of the outputs from all x-ray units in use throughout the country can be performed within a few months using this technique.

Humans↗
PubMedDate not supplied

Dynamic pulmonary imaging: performance properties of a digital fluoroscopy system.

The physical characteristics of dynamic pulmonary imaging with digital fluoroscopy, which differ from those in DSA equipment, have been determined. The spectral distributions and mean energies were calculated and corresponding exposures with varying high voltage and copper filtration (60-100 kVp, 0-2.83 mm Cu) were measured. The utilization of 90-100 kVp with a filter consisting of 1.39 mm Cu and 3 mm Al minimized disturbing skeletal artifacts and reduced the radiation exposure by a factor of approximately 5 in comparison with imaging at 60 kVp without copper filtration. Simultaneously, the measured signal decreased by about 25%. The mean energy of this spectrum exceeded that of 140 kVp chest imaging. The dynamic pulmonary imaging method produces logarithmically transformed x-ray transmittance values linearly related (r = -0.999) to water thickness between 7-10.5 cm, which is equivalent to the normal range of the chest in pediatric patients. A good linear correlation (r = 0.933,N = 92) was obtained when the change in transmitted radiation was compared with tidal volume measured in a rabbit model using a pneumotachometer. The results indicate that the method is applicable for quantitative measurements of pulmonary ventilation. Changes in tidal ventilation can be measured with this noninvasive x-ray imaging technique.

Animals↗
PubMedDate not supplied

K-ras and p53 mutations and overexpressions as prognostic factors in female rectal carcinoma.

BACKGROUND: The present study was undertaken to determine the prognostic significance of K-ras, p53 and bcl-2 in female rectal carcinoma. MATERIALS AND METHODS: The mutations in K-ras and p53 genes were analysed using SSCP and direct sequencing. The expression of K-ras, bcl-2 and p53 proteins was determined immunohistochemically. RESULTS: Mutations of K-ras and p53 genes were detected in 12% and 38% of the tumours, respectively. The prevalence of K-ras overexpression was 67%. K-ras mutations were not associated with survival. However, more favourable survival was observed for patients with K-ras overexpression than with normal expression (adjusted hazard ratio from Cox model 0.4, 95% CI 0.2-0.8). Mutation or overexpression of p53 were not associated with survival. CONCLUSIONS: It may be possible, that the mutations and protein overexpression of K-ras and p53 in female rectal carcinoma have different clinical impact on patient survival as suggested in previous studies concerning colorectal carcinoma of both sexes.

Adenocarcinoma↗
PubMedDate not supplied

PACS in Japan and the Nordic Countries. First Japan-Nordic PACS symposium.

The ingredients seem to exist for switching from film-based radiology to digital radiology utilizing the concept Picture Archiving and Communication System (PACS). Why has this not happened? What are the barriers limiting the diffusion of PACS into health care? This was the theme of the 1st Japan-Nordic Symposium in PACS, which was held in Tokyo, March 29-30, 1990. Over 40 radiologists and technical specialists in PACS participated. The topics discussed ranged from the present status of PACS in Japan and the Nordic Countries, to functional specifications and user requirements for PACS, to organizational and other changes brought about by PACS and to teleradiology as a solution for communication of images over wide distances. The symposium was quite successful and will be followed by a 2nd symposium in Finland in the summer of 1991.

Humans↗