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Biomedical subjects

A Jónsson

Publications and source records attributed to A Jónsson.

At least 19 recordsLinked to original sources
PubMed2001

[The channels for important new knowledge to medical doctors. The case of Helicobacter pylori and stomach and duodenal ulcers.].

UNLABELLED: A retrospective survey of the flow of information to medical doctors as regards the relationship between Helicobacter pylori and stomach and duodenal ulcer and other gastrointestinal diseases. This is the Icelandic part of a joint study in five Nordic countries. OBJECTIVE: The objective of the research was to assess the effectiveness of different sources of information, to measure the length of time it takes for the information to spread and influence medical practice. MATERIAL AND METHODS: The information was collected with the help of questionnaires that were sent to 159 general practitioners (GP) and 110 physicians in three medical specialities. Among the questions asked were when and how the information had reached the respondents and when and how it had influenced their medical practices. RESULTS: The knowledge about Helicobacter pylori had generally reached medical doctors six to eight years after it first appeared in the medical journals and had three years later led to changes in the routine examinations and treatment. The specialists got the news one to three years earlier than the GPs and also started to prescribe antibiotics one to three years earlier. The most frequently cited source of information was international medical journals, then scientific conferences, colleagues and The Icelandic Medical Journal. The most important source was considered to be international medical journals, then scientific conferences and colleagues. A certain difference was found between GPs and the specialist doctors. More GPs said they had got information from the pharmaceutical industry or through The Icelandic Medical Journal and relied on clinical diagnosis. More specialist doctors considered the most important source of new knowledge to be the colleagues, they also said they used endoscopy and took tissue samples more often and more often considered it correct to do so. CONCLUSIONS: Only a decade after the first reports on Helicobacter pylori appeared in medical journals most Icelandic doctors had got the knowledge and were prescribing appropriate treatment, the specialist doctors in the lead. International medical journals spread the news most effectively but The Icelandic Medical Journal played only a minor role. The question is if the process could have been accelerated any further by some more hitting Icelandic news and by more definite initiative in framing guidelines.

English Abstract↗
PubMed2000

[The impact of digital techniques on radiological services.].

All diagnostic imaging examinations may be performed digitally using computer techniques. The diagnostic reading in the imaging department can be made on a specialised computer screen and the images stored in a digital archive. The referring physician uses his computer to send requests and to read the reports. He can also access the images in the archive and view the images on a standard computer screen. The X-ray departments and their communication with referring physicians will be paper- and filmless, which results in considerable changes in working routines and increased speed of service. Digital X-ray techniques are described and some examples of digital services given.

English Abstract↗
PubMed1999

[Knowledge about Helicobacter pylori and antibiotic treatment of peptic ulcer. A model study of information dissemination and implementation of the new knowledge in clinical practice].

Dissemination of information concerning new knowledge on peptic ulcer disease caused by Helicobacter pylori and treatment with antibiotics was surveyed. In 1996 a questionnaire was mailed to 200 gastroenterologists and 200 general practitioners. Physicians enumerate national medical journals as the most frequent source of information about the relationship between Helicobacter pylori and gastrointestinal ulcer. Six years after the first publication in international journals, 44% of the doctors had noticed this relation. Nearly all physicians had introduced antibiotics in treatment af peptic ulcer disease ten to twelve years after first announcement. The gastroenterologists preferred international medical journals whereas general practitioners stated national medical journals were the most important sources of new knowledge. General practitioners lacked knowledge of published guidelines for treatment of peptic ulcer disease.

Clinical Competence↗
PubMed1999

[Gaining new knowledge in clinical practice].

A study of the diffusion of knowledge about Helicobacter pylori and gastrointestinal disease among Norwegian clinicians is reported. A questionnaire about when and how research results on Helicobacter pylori and gastrointestinal disease were taken up by doctors in their practice was sent to 200 general practitioners and 200 medical and surgical gastroenterologists. This Norwegian study is part of a comparative study of the uptake process in the five Scandinavian countries which is planned to be published in an international journal. The specialists both heard of research results and started using new treatments earlier than the general practitioners. The main sources of information for the general practitioners were the national medical journal and courses or conferences, whilst the specialists obtained their information mainly from international journals and courses or conferences. The general practitioners were more likely to treat Helicobacter pylori positive dyspepsia and to use serology as a diagnostic tool, whilst the specialists were more likely to use breath tests and had a greater belief in the role of Helicobacter pylori as a cause of gastric cancer. The great majority of both groups knew of Helicobacter pylori as a cause of peptic ulcer disease, used antibiotics in its treatment, and preferred (referral to) endoscopic biopsy as the main diagnostic tool.

Adult↗
PubMed1999

Diffusion of knowledge of Helicobacter pylori and its practical application by Nordic clinicians.

BACKGROUND: The knowledge uptake by physicians in five Nordic countries about Helicobacter pylori and gastrointestinal disease was studied. METHODS: Questionnaires were sent to 1832 general practitioners (GP) and gastroenterologists (GE), and central persons were interviewed in Norway, Sweden, Denmark, Finland, and Iceland. RESULTS: Half the GEs had heard of H. pylori by 1987 and had begun eradication treatment before 1991, and half the GPs had by 1989 and 1992, respectively. By 1996 this applied to more than 90% of both groups. The most important information sources were national journals for GPs and international journals and conferences for GEs. More than 80% of respondents considered H. pylori causative for peptic ulcer, less than 50% for stomach cancer, and 10% for non-ulcer dyspepsia. Variations between countries were mostly small. CONCLUSIONS: GPs and GEs in the Nordic countries have knowledge of H. pylori, and there is broad agreement on diagnosis and treatment, although some differences exist.

Diffusion of Innovation↗
PubMed1996

Spatial resolution requirements in digital radiography of scaphoid fractures. An ROC analysis.

PURPOSE: To investigate the spatial resolution requirements in digital radiography of scaphoid fractures. MATERIAL AND METHODS: Included in the study were 60 scaphoid radiographs with and 60 without fractures of the scaphoid bone. The film-screen images were digitized using pixel sizes of 115, 170, and 340 microns along with 170 microns with a 10:1 wavelet compression. The digital images were displayed on a 1280 x 1024 x 8 bits monitor, and 5 observers evaluated the images in 5 randomized sessions. The results for each pixel size were then compared to the film-screen images by ROC analysis. RESULTS: The mean area under the ROC curves was larger for the film-screen images than for the digital images at all resolutions. However, this difference was not significant when the areas under the ROC curves for the film-screen images were compared to the digital images of 115, 170, and 170 microns with 10:1 compression. There was a significant difference for the 340-microns pixel size in favour of the film-screen images. The mean ROC curves for the digital images were very similar for the 115 and 170 microns pixel sizes, although slightly better for 115 microns. At 170 microns, the compression seemed to have a relatively small negative effect on the diagnostic performance; the deterioration was greater when the pixel size was increased to 340 microns. There was no obvious correlation between diagnostic performance and the experience of the observers in using work-stations. CONCLUSIONS: The pixel size of 170 microns is adequate for the detection of subtle fractures, even after wavelet compression by a ratio of 10:1.

Angiography, Digital Subtraction↗
PubMed1995

Computed radiography in scoliosis. Diagnostic information and radiation dose.

The diagnostic information and radiation dose in scoliosis examinations performed with air-gap technique using stimulable phosphor imaging plates were determined in a prospective study. Overlapping p.a. images of the thoracic and lumbar spine in 9 patients were obtained with 4 different exposure settings according to patient size. Equal exposure settings were used for the 2 images. Two images of 18 were judged inferior in depicting the landmarks of scoliosis measurement, requiring re-exposure. Sixteen images were judged of adequate or good quality. The mean entrance doses in the central beam for the 4 patient groups were in the interval of 0.05 to 0.12 mGy for both images. The skin doses on the breasts were in the range of 0.00 to 0.03 mGy. The presented technique thus results in a low radiation dose with sufficient diagnostic information in radiography of scoliosis.

Adolescent↗
PubMed1995

Computed vs. film-screen magnification radiography of fingers in hyperparathyroidism. An ROC analysis.

One hundred randomly selected patients with suspected or known hyperparathyroidism were examined in a prospective study of the 2nd and 3rd fingers with film-screen and digital luminescence radiographs using magnification technique. The digital images were displayed on a work-station and printed as hard-copies. Two radiologists evaluated the film-screen images regarding subperiosteal and intracortical resorption and their results were defined as "gold standard" regarding the absence or presence of these changes. Four radiologists evaluated these changes in the 3 image forms and an ROC analysis was performed. Comparing the areas under the ROC curves no significant difference was found between the film-screen images and the 2 digital display forms. These results suggest that currently available digital systems provide adequate diagnostic accuracy for evaluation of subtle skeletal changes.

Adolescent↗
PubMed1994

Film-screen vs. digital radiography in rheumatoid arthritis of the hand. An ROC analysis.

In a prospective investigation the diagnostic accuracy of film-screen and digital radiography in rheumatoid arthritis of hands was compared. Seventy hands of 36 patients with established rheumatoid arthritis were included in the study. Each of 11 joints in every hand was evaluated regarding the following radiologic parameters: soft tissue swelling, joint space narrowing, erosions and periarticular osteopenia. The digital images were obtained with storage phosphor image plates and evaluated in 2 forms; as digital hard-copy on film and on a monitor of an interactive workstation. The digital images had a resolution of either 3.33 or 5.0 lp/mm. ROC curves were constructed and comparing the area under the curves no significant difference was found between the 3 different imaging forms in either resolution group for soft tissue swelling, joint space narrowing and erosions. The film-screen image evaluation of periarticular osteopenia was significantly better than the digital hard-copy one in the 3.33 lp/mm resolution group, but no significant difference was found in the 5.0 lp/mm group. These results support the view that currently available digital systems are capable of adequate diagnostic performance.

Adult↗
PubMed1993

Delirium and dementia in acute medical admissions of elderly patients in Iceland.

A prospective study was carried out in a general hospital in Reykjavík to evaluate the prevalence of delirium and dementia among 331 patients 70 years and older who were admitted as an emergency to the medical department. Cognitive function was screened with Mental Status Questionnaire (MSQ) and Mini-Mental State Examination (MMSE) and diagnosed according to DSM-III-R for delirium and dementia. Other information obtained included social and demographic factors, drug consumption, the main condition underlying the delirium and outcome. Severe cognitive dysfunction was present in 32% of all acutely admitted patients 70 years and older, which were diagnosed further as delirium 14% and dementia 18%. At follow-up, concurrent dementia was found in 70% of the delirium patients. The main causes for delirium were cardiac failure 27%, stroke 22% and sepsis 16% and the mortality rate was 32% compared with 8% in dementia alone. The prognosis of patients with delirium and dementia depends on detecting these disorders, and the clinical skills of physicians working with acutely ill elderly patients can be improved by relatively simple screening questionnaires such as the MSQ and MMSE.

Aged↗
PubMed1992

CT of the wrist in suspected scaphoid fracture.

Bone scan and sagittal projection CT of the scaphoid was performed in 10 patients with clinically suspected scaphoid fractures. The primary and follow-up plain radiographs were negative or equivocal for fracture. CT examination demonstrated scaphoid fracture in 7 patients and normal findings in 3. It is concluded that CT of the scaphoid can replace bone scan to diagnose or rule out fracture in institutions where nuclear medicine facilities are not available.

Adolescent↗
PubMed1985

Coronary atherosclerosis and myocardial infarction in nonagenarians: a retrospective autopsy study.

Autopsy records of two groups of persons, aged 90 years and older and 70 years and younger, were analysed for coronary atherosclerosis and myocardial infarction. In each group were 74 males and 140 females who died during 1951-1980. In nonagenarians, moderate and severe degrees of coronary atherosclerosis were more frequent, but myocardial infarction both new and old was less frequent when compared with those aged 70 and younger. The sex difference in the degree of coronary stenosis within each age group was small but the frequency of myocardial infarction was less in females in both age groups.

Aged↗
PubMed1983

Comparative disease patterns in the elderly and the very old: a retrospective autopsy study.

One hundred autopsy reports of persons who died in Iceland aged 90 years or over were studied and the causes of death were recorded. Another 100 autopsy reports of persons aged 70 years and under were used as controls. The disease pattern of those aged 70 or under did not differ much from that appearing in the Icelandic National Mortality Statistics, all ages included. However, in those aged 90 and over, the number of important diseases was higher and pneumonia, in particular, occurred more frequently both as an intervening and as an underlying cause of death. In the older age group, dementia was 3.4 times more common in males and 4.7 times more common in females. Malignant neoplasms were less frequent as causes of death in the older age group. In the older age group there was a much lower frequency of myocardial infarction compared with the controls, although the degree of arteriosclerosis did not differ in these two groups.

Aged↗