Biomedical subjects

K A Thuomas

Publications and source records attributed to K A Thuomas.

77 records · Page 5Linked to original sources

PubMedDate not supplied

Magnetic resonance imaging in primary amyloidosis.

Twelve patients with primary amyloidosis (AL) were investigated with magnetic resonance imaging (MRI). In 9 patients an abnormal thickening of the heart walls was present and in 2 macroglossia was found at MRI. T1 was significantly increased in liver (p less than 0.05) and subcutaneous fat (p less than 0.01) while it was decreased in the spleen (p less than 0.05). T2 was significantly decreased (p less than 0.01) in the spleen in patients with amyloidosis, while it was not significantly altered in the liver or subcutaneous fat. After therapy T1 of the liver was reduced towards normal values in 4 patients. It is concluded that MRI might be a method to quantitate the amount of amyloid deposits in the tissue, and that the effect of therapy may be monitored with this technique.

Aged↗

PubMedDate not supplied

Relaxation enhancement of the dog liver and spleen by biodegradable superparamagnetic particles in proton magnetic resonance imaging.

Bio-degradable superparamagnetic particles of about 0.5 micron diameter were investigated in 2 dogs as potential intravenous contrast enhancing agents for the reticuloendothelial system. The particles lowered the MRI signal of the liver for all investigated sequences, while the signal of the spleen was lowered only in T2 weighted sequences. No clear effect was seen on signals of fat and muscle. There was a pronounced effect on T2 in both liver and spleen but relatively little effect on T1. Diminishing contrast effect with time indicates that the particles degrade. The particles did not have any adverse effects on the general state of the dogs or on routine liver and kidney function tests.

Animals↗

PubMedDate not supplied

Magnetic resonance imaging with maximum contrast between two selected tissues composed of recordings with three repetition times.

A method is presented which in a composed image maximizes the image intensity difference between two selected tissues. The composition is made from several magnetic resonance (MR) images from the same slice but with different MR imaging parameters. The method is illustrated with a patient with liver metastases for whom the technique was used to emphasize metastases above normal liver parenchyma.

Carcinoid Tumor↗

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

MR imaging of syringohydromyelia and Chiari malformations in myelomeningocele patients with scoliosis.

The brain and spinal cord were examined with MR imaging in 30 myelomeningocele patients 3-32 years old to study the prevalence of syringohydromyelia and Chiari malformations and to correlate these conditions with developmental scoliosis and spontaneously arrested hydrocephalus. Twelve patients had neurologic deficits above the level of the myelomeningocele and 10 had spontaneously arrested hydrocephalus. MR visualized syringohydromyelia in four patients with widened or focally bulging spinal cords and in eight patients with atrophic spinal cords. All patients had Chiari malformations, 28 of type II and two of type I. Syringohydromyelia was not correlated with type of scoliosis, result of ventriculoperitoneal shunting procedures, radiologic level of the myelomeningocele, or extent of the Chiari malformation. The two patients with the most rapid progression of thoracic scoliosis had the most extensive syringohydromyelia and radiologically low lumbar levels. Neurologic deterioration due to syringohydromyelia and Chiari malformations is probably more common in myelomeningocele than has been recognized previously and may cause developmental scoliosis, loss of ambulation, impaired extremity function, and progressive cranial nerve paralysis.

Adolescent↗