Biomedical subjects

T Andersson

Publications and source records attributed to T Andersson.

330 records · Page 19Linked to original sources

PubMedDate not supplied

Field-echo pulse sequences used under suspended respiration for detection of liver metastases.

To obtain a fast MRI sequence for detection of liver metastases under suspended respiration, two healthy volunteers were examined with the field echo sequence FLASH, using a large number of repetition times, echo times, flip angels and matrix sizes. The spleen was used to simulate liver metastases and contrast-to-noise ratios between liver and spleen were calculated and the sequence with the highest ratio was considered optimal. The different FLASH sequences were also compared with spin echo sequences using short repetition and echo times. A FLASH sequence with a repetition time of 140 ms, an echo time of 14 ms, a flip angle of 80 to 100 degrees and a matrix size of 128 x 256 was considered the most suitable for detecting liver metastases. This sequence, together with other FLASH and spin echo sequences, were used for examination of five patients with liver metastases from endocrine gastrointestinal tumours.

Adult↗

PubMedDate not supplied

Contrast enhancement of pathologic lymph nodes demonstrated by computed tomography.

Enlarged mediastinal, retroperitoneal and pelvic lymph nodes are often difficult to differentiate from vascular structures. Contrast medium is therefore used to help to discriminate arteries and veins from lymph nodes. This study was undertaken to investigate the degree to which pathologic lymph nodes become enhanced after an intravenous bolus injection of contrast medium. Computed tomography was performed in 25 patients with enlargement of retroperitoneal lymph nodes due to primary lympho-proliferative disease or metastases. A dynamic sequence of a well delineated lymph node was obtained over a period of two minutes. Contrast enhancement was seen in all lymph nodes, but of varying degree. The enhancement was correlated to that observed in the inferior vena cava. Most examined lymph nodes showed slight or moderate enhancement, but in five instances strong enhancement, more than 75 per cent of that of the vena cava, was found. These nodes could possibly have been misinterpreted as blood vessels.

Adult↗

PubMedDate not supplied

Angiography, computed tomography, magnetic resonance imaging and ultrasonography in detection of liver metastases from endocrine gastrointestinal tumours.

Twenty-five patients with endocrine tumours (13 with endocrine pancreatic tumours and 12 with carcinoids) were examined with angiography, computed tomography, magnetic resonance imaging and ultrasonography. Seventeen patients had liver metastases and were followed between 3 and 66 months with serial examinations during treatment with chemotherapeutic agents and interferon. The efficiency of the various techniques to detect metastases was investigated. Analysis of changes in tumour size during treatment was made to see if treatment effects could be monitored with radiologic examinations. Ultrasonography was the best non-invasive method for detection of metastases and is recommended as standard method for imaging in this group of patients. Angiography was even better showing extremely small metastases, less than 5 mm, and is recommended in selected cases. With one exception, no significant change in tumour size was noted in spite of clear laboratory and clinical signs of therapy effect indicating that tumour size determination is not useful for therapy monitoring in this type of disease.

Adenoma, Islet Cell↗

PubMedDate not supplied

Effect of interferon on T1 relaxation times of liver metastases from endocrine gastrointestinal tumours.

Eight patients with liver metastases from endocrine gastrointestinal tumours were examined with magnetic resonance imaging of the liver before and during treatment with interferon. T1, T2 and tumour size were measured and compared with tumour marker levels and symptomatic improvement or deterioration. Before therapy all tumours showed a long T1 and T2, in comparison to normal liver and fat, and during therapy they all showed a decrease in T1. As no change in liver T1 and fat T1 occurred, the decreased tumour T1 is considered to be a therapy effect. This cannot be fully explained but is possibly due to a reduction in tumour growth rate during interferon treatment. There was no certain correlation between tumour T1 and tumour marker levels or symptomatic changes.

Carcinoid Tumor↗

PubMedDate not supplied

Biotransformation of 7-ethoxycoumarin in isolated perfused rainbow trout liver.

A reliable technique for rainbow trout liver perfusion has been developed for studies on xenobiotic biotransformation. Normal function of the perfused liver was indicated throughout the perfusion experiment by 1) a proper oxygen consumption, 2) a low leakage of intracellular enzymes, 3) a stable pH value in the effluent, and 4) a stable release of metabolites into the effluent perfusate and bile for at least 2 hr after maximal rate of metabolism was attained. The main metabolite of 7-ethoxycoumarin in effluent perfusate was identified as 7-hydroxycoumarin glucuronide. Only trace amounts were identified as sulfates. When fish were pretreated with Clophen A50 or beta-naphthoflavone, the amount of metabolites released into the effluent perfusate increased 3.4- and 6.4-fold, respectively, when compared to control livers. Furthermore, in livers from Clophen A50- or beta-naphthoflavone-treated fish, only 80 and 67%, respectively, of excreted products were conjugated. Influence of temperature on 7-ethoxycoumarin metabolism was studied in perfused liver and isolated liver microsomes. Results indicate that the Q10 for the metabolism of 7-ethoxycoumarin in perfused liver deviates from that found in isolated microsomes. The amount of metabolites excreted into the bile consisted of about 25% of the amount found in effluent perfusate. The only metabolite detected in bile from perfused liver from control as well as treated fish was 7-hydroxycoumarin glucuronide.

Animals↗

PubMedDate not supplied

A comparison of motor evoked potentials and somatosensory evoked potentials in patients with multiple sclerosis and potentially related conditions.

Central motor conduction (CMC) and central sensory conduction (CSC) studied by means of magnetic cortical stimulation and recording of somatosensory evoked potentials, were examined and compared in 87 patients with multiple sclerosis or potentially related conditions. In all groups of patients (either grouped by diagnosis, clinical symptomatology or disease duration) there were more aberrations in CMC compared to CSC. This difference became statistically significant when all patients were taken together. By both methods we were able to detect signs of clinically silent lesions and these were often restricted to either of the pathways.

Adolescent↗