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Biomedical subjects

R Nyman

Publications and source records attributed to R Nyman.

At least 55 records · Page 3Linked to original sources
PubMed1990

Magnetic resonance imaging of sacroiliac joint inflammation.

A consecutive series of 27 patients with symptoms compatible with sacroiliitis underwent magnetic resonance imaging (MRI) of the sacroiliac joints. The diagnostic sensitivity of MRI was similar to that of computed tomography or conventional radiography. However, MRI seems to have the potential of providing unique information about the disease process in sacroiliitis by demonstrating abnormalities in subchondral bone and periarticular bone marrow. The results of this study suggest that early inflammatory changes in sacroiliitis occur in the subchondral structures of the sacroiliac joints.

Adolescent↗
PubMed1990

Posterior stabilization of the cervical spine in rheumatoid arthritis: clinical results and magnetic resonance imaging correlation.

Thirteen patients with atlantoaxial dislocation(s) had posterior stabilization and were evaluated clinically with magnetic resonance (MR) imaging and conventional radiography both pre- and postoperatively. Cases with anterior instability had large periodontoid granulomatous pannus formation, but this was lacking in cases with fixed cranial settling. The pannus caused cord compression in four cases and occupied the entire anterior subarachnoid space in four other cases. After stabilization, the granuloma decreased in size in all patients and in four cases it vanished completely. Major signs of myelopathy corresponded to cord compression at MR imaging. Minor possible signs of neural deficit were found in seven cases and their importance was not clearly understood before surgery, but because all preoperative symptoms disappeared, it was necessary to check for even obscure signs as early warnings of a threatening myelopathy.

Adult↗
PubMed1990

Magnetic resonance imaging of the transplanted kidney. Correlation to function and histopathology.

Interstitial fibrosis is a frequent finding in biopsies from long-term renal allografts, and may be due to chronic cyclosporine nephrotoxicity or chronic rejection. In this study, long-term renal transplants were investigated with magnetic resonance (MR) imaging, and the results were correlated to histopathology and graft function. Seventeen patients were investigated with MR one to 10 years after transplantation and with simultaneous ultrasonographically guided cortical needle biopsy and function tests. Histopathology included semiquantitative grading of degree of fibrosis and quantitation of ratios of tubular structures to interstitial tissue. The correlation between the histopathological assessment of interstitial fibrosis and graft function was good. Poor differentiation between the renal cortex and the renal medulla at MR imaging was correlated to high degree of interstitial fibrosis in the kidney transplants as well as to reduced graft function. MR examination may thus be of value in the evaluation of long-term renal transplants with chronic functional changes.

Adult↗
PubMed1990

Magnetic resonance imaging of acute myocardial infarction in pigs using Gd-DTPA.

Six pigs with coronary artery occlusion were investigated with MR imaging before and subsequently for about 2.5 hours at repeated intervals after the intravenous administration of Gd-DTPA (0.4 mmol/kg). The animals were sacrificed after a total occlusion time of 6 hours and the hearts were excised. The excised hearts were then reexamined in the MR equipment and stained with TTC (triphenyl tetrazolium) in order to define areas of infarction. Four control hearts with 6-hour-old infarctions were only imaged ex vivo without any previous administration of contrast media. In vivo, there was no clear demarcation of infarction with or without Gd-DTPA. Ex vivo, without any contrast media, the infarctions were poorly discriminated with a discretely increased signal intensity relative to normal myocardium in the T2 weighted images. Gd-DTPA was found to accumulate in the infarctions, which caused an elevated signal intensity most pronounced in the T1 weighted images. This considerably improved the delineation of the infarcted area.

Animals↗
PubMed1989

Late relapses after treatment for acute lymphoblastic leukemia in childhood: a population-based study from the Nordic countries.

Seven late relapses of acute lymphoblastic leukemia occurring 5.5 to 12.3 years after cessation of therapy are reported in 986 patients who had discontinued treatment for leukemia acquired before the age of 15. The study covers patients from the five Nordic countries. Of the 434 patients with ALL who had passed 5 years of follow-up without recurrence, seven have subsequently relapsed so far; an estimated cumulative proportion of 6.9% within the 10 years. In addition, we report a girl 15.9 years old at diagnosis who relapsed 7.3 years after cessation of therapy. These findings confirm that "cure" of acute lymphoblastic leukemia treated in the 1970s cannot be considered definite, even 5 years after discontinuation of therapy.

Adolescent↗
PubMed1989

Neonatal septicaemia in Finland 1981-85. Predominance of group B streptococcal infections with very early onset.

A survey of blood culture-confirmed neonatal septicaemia was carried out in seven delivery hospitals in 1981-85, for a second successive five-year period. The total number of cases was 377, to compare with 410 in the previous five-year period. Group B streptococcus (GBS) was throughout the major pathogen (29%), followed by Staphylococcus aureus (15%) and Escherichia coli (14%), while Staphylococcus epidermidis (10%) has emerged as a significant new causative agent. Septicaemia with very early onset was predominant: 49% of the cases had onset within the first 24 hours; in the majority the symptoms were present from birth. GBS was responsible for 49% of the cases detected in the first 24 hours of life. The overall mortality was 20% as compared to 23% in the previous five-year period, whereas in the very early onset septicaemia mortality was now 18%, down from the preceding 30%. Despite the modest progress, GBS septicaemia with very early onset remains a significant problem, and effective preventive measures are needed.

Finland↗
PubMed1989

Relative proton density and relaxation times in liver metastases during interferon treatment.

Relaxation times and relative proton densities were calculated from magnetic resonance examinations of the liver in eight patients with liver metastases from neuroendocrine tumours. Single, spin-echo sequences with eight different repetition times and a four-echo sequence were used to calculate T1 and T2 in tumour and normal liver, and the proton density tumour-liver quotient, before and during treatment with interferon. Changes over time of these parameters were compared with variations in tumour marker levels and changes in size and number of the metastases. During therapy, six out of eight cases showed a decrease in tumour T1, five responding to therapy and one with stationary disease, while the two patients with progressive disease showed unchanged tumour T1. The proton density quotient also decreased in a corresponding way, indicating a change in water content in tumours responding to interferon therapy. No significant change in liver T1, tumour T2 or liver T2 occurred in any patient. It is thus possible to perform reliable measurements of relaxation parameters over time, which may be valuable in follow-up of tumour treatment.

Adult↗
PubMed1989

Implantable drug delivery systems in computed tomography and magnetic resonance imaging--a comparison between titanium and stainless steel.

The effect of implantable drug delivery systems on computed tomography (CT) and magnetic resonance imaging (MRI) was investigated in a phantom and in two patients. The implantable systems of identical construction consisted either of medical grade titanium alloy or stainless steel. Images of a phantom showed artefacts of the stainless steel port in both CT and MRI. These artefacts were substantially reduced in images of the titanium port. Similar results were found in situ in two patients.

Catheters, Indwelling↗
PubMed1986

T1, T2, and relative proton density at 0.35 T for spleen, liver, adipose tissue, and vertebral body: normal values.

An MRI installation (Magnetom, Siemens, software version B1 of NUMARIS) working at 0.35 T was used to estimate T1, T2, and relative proton density in the spleen, liver, adipose tissue, and vertebral body in 14 healthy volunteers. Two double-echo sequences were applied for all subjects: TR = 500 ms, TE1 = 35 and TE2 = 70 ms; and TR = 1600 ms, TE1 = 35 and TE2 = 70 ms. The images were sampled in regions of interest and appropriate relaxation expressions fitted to the ROI data yielding relaxation parameters and relative proton densities. Relaxation expressions, included in standard software (Siemens), were compared to more elaborate functions, developed in parallel to this study. The latter were found more appropriate, especially for high T1 values, and gave the following mean values for the four tissues (estimated uncertainty of mean in parentheses) T1 (ms) 915(36), 428(5), 261(7), and 501(11); T2 (ms) 79.7(8.8), 51.0(0.2), 59.8(1.0), and 64.7(0.8); and corresponding relative proton density (rho, arbitrary units) 2088(136), 2182(10), 2915(49), and 2136(21). The uncertainty in the values was estimated in the fitting procedure and does not include systematic errors. The relative noise in the ROIs was about 9% and the reproducibility of the ROI mean values about 8%.

Adipose Tissue↗
PubMed1985

Neonatal septicaemia.

A total of 410 proved cases of neonatal septicaemia from seven Finnish hospitals seen between 1976 and 1980 were reviewed. The annual incidence of neonatal septicaemia was 3 per 1000 births, and overall mortality was 23%. Onset was early in most patients. Symptoms of septicaemia occurred within the first 24 hours of life in 44% and within the first week of life in 90%. In the very early onset disease (within 24 hours) mortality was 30%, compared with 17% in all other cases. Group B streptococcus was the leading cause in very early onset disease (52%) but mortality from infection with this organism was similar to that in other very early onset cases. It is concluded that very early onset neonatal septicaemia, probably of intrauterine origin and caused by group B streptococcus in one half of the cases, constitutes the major form of neonatal septicaemia in Finland and should receive the highest priority in preventive measures.

Enterococcus faecalis↗
PubMedDate not supplied

Selection of patients with lower limb arterial occlusive disease for endovascular treatment of the iliac arteries with duplex scanning.

The aim of this study was to evaluate the role of duplex scanning in selection of patients with lower limb arterial occlusive disease for endovascular treatment of the iliac arteries. From January 1995 through May 2000, 183 patients having chronic lower limb arterial insufficiency who underwent duplex scanning of the lower extremity arteries with available aortoiliac scans within 3 months before conventional aortoiliac diagnostic angiography and/or endovascular intervention of the iliac arteries were studied retrospectively. The findings obtained from duplex scanning and angiography were analyzed in a blinded manner by 2 investigators. Limbs having category 1, 2, and 3 lesions according to duplex scan findings were interpreted as being suitable for endovascular intervention. The comparison between duplex scan findings and angiography was analyzed by the third investigator. During 93 percutaneous transluminal angioplasty (PTA) procedures, 133 arterial segments, common or external iliac, were dilated with stent placement in 70. Bilateral interventions were performed in 25 cases, and of 68 unilateral interventions, 57 were at only 1 arterial segment. The accuracy, sensitivity, specificity, and negative and positive predictive values of duplex scanning to appropriately categorize the iliac artery lesions into suitable or unsuitable for endovascular intervention were 90%, 95%, 83%, 90%, and 92%, respectively when the inconclusive duplex scans were excluded (11%). In 6 patients with lesions suitable for PTA according to duplex scanning and angiography, PTA was not performed owing to clinical reasons. The accuracy of duplex scanning in predicting the performance of endovascular intervention was 88%. It is concluded that iliac artery endovascular procedures in limbs with chronic occlusive disease can be reliably planned according to duplex scan findings.

Adult↗