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Biomedical subjects

M Kormano

Publications and source records attributed to M Kormano.

At least 199 records · Page 11Linked to original sources
PubMedDate not supplied

Tissue characterization of intracranial tumors by magnetization transfer and spin-lattice relaxation parameters in vivo.

T1s and magnetization transfer (MT) parameters of 36 intracranial tumors were determined in vivo at 0.1 T to assess their use in tissue characterization. The mobile water relaxation times (T1w) did not differ between tumor groups, whereas the T1s, the apparent MT relaxation times (T1a), and the parameters MT contrast (MTC) differed significantly between several tumor types. The MT rates (Rwm) demonstrated the most significant differences; Rwm values could reliably separate high grade and low grade gliomas. T1ws of the tumors were commonly in the same range as that of normal gray matter, whereas other parameters differed from those of normal brain. The results indicate that MT rates are superior to other parameters in the characterization of intracranial tumors and may be also useful clinically in the grading of gliomas.

Adenoma↗
PubMedDate not supplied

Radiology in the Nordic Countries.

NEMT, Nordic Evaluation of Medical Technology, conducted a study in 1988-89 on the use and diffusion of diagnostic radiology technologies in Denmark, Finland, Iceland, Norway and Sweden, i.e. the Nordic Countries. The study analysed the responses to a questionnaire sent to all Nordic radiology departments. Our findings show a variation from about 500 to nearly 900 radiology examinations per 1000 inhabitants among the Nordic Countries. Some of the differences are explained by unique structural factors of the health care system in each country, even if they all provide comparable public health services. Other differences are explained by variations in medical practice, accessibility to new imaging modalities, and replacement policies. This paper summarizes the results of the study.

Diffusion of Innovation↗
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

User requirements for IMACS.

User requirements of an IMACS are briefly reviewed with special reference to image matrix, number of simultaneous images for review, and connection to the hospital information system. In addition, the problems of information transmission between clinicians and radiologists are discussed--an aspect which varies between different medical communities. Methods of limiting the amount of archived data are also briefly commented upon.

Computer Systems↗
PubMedDate not supplied

Negative gastrointestinal contrast enhancement and image distortion induced by superparamagnetic particles at 0.02 Tesla.

Gastrointestinal contrast enhancement and image distortion induced by superparamagnetic particles were evaluated in vitro and in rabbits at 0.02 Tesla. Test tubes containing 0.01-1.0 mg particles/ml were imaged in an oil or water bath in order to demonstrate the concentration-dependent signal void and image distortion in vitro at several pulse sequences. The lowest concentration of particles tested clearly decreased the signal intensity. Image distortion was observed when the concentration exceeded 0.07 mg/ml and was more pronounced on the T2-weighted images. The in vitro T2 relaxation time decreased from 122 ms to 56 ms with an increase in the particle concentration from 0.01 to 0.06 mg/ml. A loss of the GI-tract signal was observed in rabbits after the administration of 1 mg particles/kg, given as a 0.03 mg/ml suspension. At a dose of 20 mg/kg (0.6 mg/ml suspension) significant image distortion was observed.

Contrast Media↗
PubMedDate not supplied

Microangiography of rejected human kidney transplants.

A microangiographic study of 17 rejected and surgically removed human kidney transplants, three transplants removed for other reasons and two adequately perfused and preserved but not transplanted cadaver kidneys was performed. Transplants rejected with acute clinical course showed poor or variable glomerular filling and tapering cortical arteries with no impairment of medullary perfusion, more extensively in those transplants showing poor initial function. Chronic rejection, independent of other parameters showed lack of cortical perfusion, and glomerular filling; impaired perfusion of whole segments, arterial wall narrowing and changes secondary to kidney shrinkage. The radiographic patterns of chronic and acute rejection were distinguishable from each other and from nonrejected specimens.

Angiography↗
PubMedDate not supplied

Hepatography and liver lymphography by retrograde biliary ethiodol infusion: an experimental study in the dog.

Ethiodol in dosages of 0.5-3 ml/kg was retrogradely infused with hydrostatic pressure of 50--100 cm water into the biliary system of nine cholecystectomized dogs equipped with a Thomas cannula in the second portion of the duodenum, allowing cannulation of the common bile duct with a Foley catheter under direct vision. A total of 18 examinations were performed. A dense hepatogram and complete visualization of the hepatic lymph nodes were obtained when the infused Ethiodol dosage exceeded the capacity of the biliary system by 10 ml or more. The hepatogram lasted for three to four months and the lymph nodes were opacified for a year and longer. Contrary to angiographic contrast agents, Ethiodol retrogradely infused into the biliary system primarily refluxes from the biliary system to the lymph and not to the blood. Judged by serial chest radiographs and lung scans, pulmonary Ethiodol emboli did not occur. A significant temporary increase in serum bilirubin and liver enzymes followed the procedure but these returned to normal within a week to a month. Periodic needle biopsies of the liver showed Ethiodol droplets initially in the interstitium and lymphatics, and subsequently in hepatocytes, Kupffer's cells and the epithelium of small bile ductules. No hepatic damage was found histologically on long-time follow-up examinations.

Animals↗
PubMedDate not supplied

The diagnostic potential of contrast enhancement pharmacokinetics.

Diastizoate concentrations in the blood and twelve tissues and organs of 20 rats were measured at 40 seconds, and 2, 5, 15 and 60 minutes after bolus intravenous administration of 125 I-labeled diatrizoate and 131 I-labeled albumin. Contrast enhancement (HU) and distribution volumes(%) were calculated from this data, and the results are presented graphically. The tissues can be separated into two groups according to the rapidity of extravascular contrast medium uptake. The liver appeared to concentrate the contrast medium. Curves of local contrast enhancement with time could be constructed by a CT scanner from the data of several consecutive scans and are of potential importance in the differential diagnosis of lesions detected on CT. Repeat postcontrast CT scans could be used to detect and characterize lesions which raise a diagnostic problem. The potential diagnostic advantages of calculating percent distribution volumes from CT scans are demonstrated and discussed.

Animals↗
PubMedDate not supplied

Toxicity of X-ray contrast media in cell cultures.

Monolayer cell culture techniques for neuronal and glial cells and fibroblasts were used for the investigation of the direct toxicity of x-ray contrast media. The effect of various concentrations of sodium diatrizoate, methylglucamine salts of diatrizoate, iothalamate, iodamide, metrizamide, iocarmate, ioserate, and ioglycamate were studied. The intravenous biliary contrast medium--ioglycamate--was most toxic to all cell types. All the contrast media studied were somewhat toxic to neurons in the concentration of 50 mmol/l and showed variable glial toxicity. In equiosmolar concentrations the contrast media studied showed toxicity on neurons in the following order: iothalamate, diatrizoate, iodamide, ioserate, iocarmate, ioglycamate. Fresh metrizamide solution in equimolar concentrations showed the least toxic effects on neurons but interfered considerably with the growth and survival of glial cells. Metrizamide solution proved to be highly toxic to neurons when refrigerated for two weeks. Methylgucamine iocarmate produced a peculiar swelling of fibroblasts.

Cell Survival↗
PubMedDate not supplied

Dynamic contrast enhancement of the upper abdomen: effect of contrast medium and body weight.

Contrast enhancement (CE) of the aorta, liver, and spleen was studied in dynamic body computed tomography (CT) in 71 patients. Four contrast media (CM) (diatrizoate, ioxithalamate, ioxaglate, iopamidol) were injected intravenously in equal bolus doses of 18.5 g iodine. Iopamidol produced the highest average peak and 2-minute aortic CE, significantly different from ioxithalamate (P less than 0.001), diatrizoate (P less than 0.01), and ioxaglate (P less than 0.0125) at peak levels. Two-minute CE values of the aorta were highest with iopamidol as were peak and 2 minute CE of the liver and spleen. A linear, inverse relationship between body weight and CE was present both at peak CE and after 2 minutes in all tissues. The nonionic CM appear to have best dose efficiency in the vascular phase of dynamic CT. These results are also applicable to digital angiography. Differences in the CE of parenchymal organs with different CM are so small that they are unlikely to have clinical significance.

Aortography↗