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Biomedical subjects

T Bach-Gansmo

Publications and source records attributed to T Bach-Gansmo.

29 records · Page 2Linked to original sources
PubMed1990

Oral superparamagnetic particles for magnetic resonance imaging. Effect in plain and viscous aqueous suspensions.

As a potential gastrointestinal MR contrast medium magnetic particles have been evaluated in preclinical studies as well as in healthy volunteers. The main problem was to achieve an even distribution of the aqueous suspension of magnetic particles in the entire intestine. To improve the distribution of the contrast medium, a viscosity-increasing agent was added to the preparation. In the plain aqueous suspension the magnetic particles sedimented rapidly and caused artifacts, whereas no such sedimentation occurred in the viscous preparation. The contrast effect, as well as the presence of artifacts, increased with particle concentration. The general contrast effect was good in all 5 volunteers, and the contrast medium was well distributed in the small intestine, including the duodenum. There were no artifacts observed, and the contrast medium was well tolerated. The viscosity-increasing agent will thus be introduced in further clinical studies.

Adult↗
PubMed1988

Clinical trial program for iopentol. A new nonionic ratio 3.0 contrast medium with emphasis on clinical phases I and II.

Iopentol is a new nonionic, water-soluble ratio 3.0 roentgen contrast medium (CM) for vascular use. The aim is to present the vascular clinical trial program for iopentol and to report the findings from the clinical phases I and II. The clinical program started with an intravenous (IV) safety and pharmacokinetic phase I trial (24 volunteers) and continued with six open, noncomparative phase II trials (61 patients) for studying cardiovascular and arterial tolerance (two trials in cardioangiography), venous tolerance (two trials in IV computed tomography [CT] enhancement), and cerebral and arterial tolerance (2 trials in cerebral arteriography). One volunteer in the phase I trial was excluded because of a vasovagal reaction following saline injection, and four patients were protocol deviators in cardioangiography. Mainly renal glomerular filtration of unmetabolized iopentol, close to 100% recovered after 24 hours in the urine, was found in the phase I study. No unexpected or severe contrast-induced reactions were encountered in phases I and II. Good diagnostic efficiency was obtained in phase II. As also expected, iopentol seemed to be well-tolerated. However, its relative efficiency and tolerance profile can only be documented from the ongoing comparative phase III trials.

Contrast Media↗
PubMed1988

Risk of seizures after myelography: comparison of iohexol and metrizamide.

A parallel, double-blind, randomized study comparing iohexol and metrizamide--both 180 mg l/ml--in lumbar myelography was carried out in 60 consecutive patients. Eight to 15 ml of contrast medium were administered with the upper level at the middle thoracic column. A detailed neurologic examination was performed before and 24 hr after myelography. EEG recordings--evaluated visually and with fast Fourier transformation analysis--and somatosensory evoked responses were registered before, 6 hr after, and 24 hr after myelography. All patients were observed for adverse reactions for 24-48 hr. Iohexol did not produce any epileptiform activity but epileptiform activity was detected in five patients receiving metrizamide. Iohexol produced significantly less frequent and less severe EEG changes than did metrizamide both at visual evaluation (p less than .0025) and at fast Fourier transformation analysis (p less than .04). No significant changes occurred in the early components of the somatosensory evoked potentials after either contrast medium. Iohexol caused significantly (p less than .002) less frequent and less severe adverse reactions than did metrizamide. The neurologic examination revealed no changes of clinical importance with either contrast agent.

Double-Blind Method↗
PubMed1986

Lumbar myelography with Omnipaque (iohexol).

Lumbar myelography with iohexol (Omnipaque) was performed in 103 consecutive adult patients with low back pain or sciatica. The patients were observed for 48 h with registration of possible adverse reactions. Mild or moderate transient side effects were recorded in 24 patients. No serious adverse reactions were noted, and EEG recorded in 25 patients showed no changes.

Electroencephalography↗
PubMed1984

Cervical myelography with iohexol.

An open study with iohexol (Omnipaque) in cervical myelography has been performed in 20 patients to evaluate the properties and neurotoxicity of this new water soluble contrast medium. The image quality was good (30%) or excellent (70%) in all cases. The frequency of headache was 25%. No EEG changes were severe and the total frequency was 20%. We conclude that this study supports other reports of iohexol having a low neurotoxicity and is well suited for intrathecal use.

Adult↗
PubMedDate not supplied

Contribution of oral magnetic particles in MR imaging of the abdomen with spin-echo and gradient-echo sequences.

An open phase III clinical trial of the oral contrast agent OMP (oral magnetic particles) was performed in 35 patients undergoing abdominal magnetic resonance (MR) imaging at 1.5 T with axial spin-echo and gradient-echo sequences. The diagnostic efficacy of OMP was examined by comparing pre-and postcontrast images. Bowel loops and abdominal organs were more easily recognizable after OMP ingestion, and the general quality of the images was improved because of fewer bowel-related artifacts. The diagnostic value of the postcontrast abdominal MR examination was superior or equal to that of the precontrast study, and additional information was obtained in 44% of the cases. Postcontrast gradient-echo sequences increased confidence in the MR examination in 18% of cases. OMP was well tolerated and increased the quality and amount of diagnostic information acquired during the examination. Gradient-echo imaging was found to be a useful complement, but the need for a reduction in susceptibility artifacts was apparent and indicates that a decrease in TE or the use of rapid spin-echo sequences might be advantageous.

Abdomen↗
PubMedDate not supplied

Delineation of liver necrosis using double contrast-enhanced MRI.

The purpose of this study was to demonstrate the potential usefulness of the combination of gadolinium and dysprosium to enhance the different between normal and necrotic liver tissue. Small regions of acute necrosis were induced by injecting 200-300 microliters of 95% alcohol into the liver of 26 rats. MRI was performed 24 hours after necrosis induction, before and immediately after injection of one or both contrast agents. Using a mixed T1/T2-weighted sequence, the signal intensity of (SI) of the normal liver was reduced by 70%, whereas the necrotic regions had more than a 50% increase in SI after double contrast. The region that was enhanced corresponded largely with the region of necrosis as observed postmortem. The lesion size, when identified, was largely underestimated using either of the agents along, albeit using the common pulse sequences. The double contrast effect of simultaneous administration of gadolinium and dysprosium allows accurate delineation of liver necrosis.

Animals↗
PubMedDate not supplied

Effect of superparamagnetic particles as oral contrast medium at magnetic resonance imaging. A phase I clinical study.

Non-biodegradable superparamagnetic particles were used as an oral contrast medium in different concentrations, and evaluated in 25 human volunteers. The aim of the study was to determine the most appropriate concentration of the contrast medium, and to evaluate the effect, distribution, safety and tolerance. With the concentration of 1.0 g/l a substantial reduction of the signal intensity in the bowel was achieved in both T1 and T2 weighted images. The intraabdominal structures were well differentiated from the bowels containing contrast medium. 'Metal' artifacts and blurring of adjacent structures, probably due to an increased local concentration, were observed at higher dosages. The distribution of the preparation in the gastrointestinal tract varied between individuals. As a rule a good contrast effect was achieved in the small bowel with the exception of the duodenum. The contrast medium was well accepted and did not cause any side effects of clinical importance. The results suggest that the preparation is well tolerated by humans and may be a useful contrast medium for abdominal MR imaging.

Contrast Media↗
PubMedDate not supplied

Iohexol: summary of North American and European clinical trials in adult lumbar, thoracic, and cervical myelography with a new nonionic contrast medium.

Iohexol, a new water-soluble nonionic contrast medium, was evaluated in clinical trials in Europe and North America for lumbar, thoracic, and cervical myelography using direct C1-2 or lumbar puncture. Iohexol was administered at 180, 240, or 300 mg I/ml to 677 adult patients for visualization of the lumbar subarachnoid space, and to 368 adult patients for evaluation of the cervical area. Compared with metrizamide, use of iohexol resulted in equivalent opacification but significantly reduced patient morbidity (headache, nausea, vomiting, dizziness). No epileptogenic activity was recorded in over 370 patients receiving iohexol. No mental or psycho-organic syndrome manifestations were observed in any of the 1,045 patients receiving iohexol. Adverse reactions occurring after iohexol injection were not related to the concentration or site used or to total dose administered. Iohexol has, thus far, proven superior to metrizamide for myelography.

Adult↗