Functional analysis of magnetic resonance studies of the heart.

To calculate left ventricle volumes and ejection fraction, magnetic resonance images (MRI) were acquired in an oblique position in end-diastole and end-systole. The ejection fraction values were compared with results of gated blood pool studies with 99mTc-labelled erythrocytes (correlation coefficient 0.8).

The influence of elevated iodide supply on the autonomously functioning thyroid gland.

A pharmacokinetic two-compartment model of iodine metabolism has been established on the basis of data from the literature and our own experimental investigations. By this model it is possible to estimate the effects either of prolonged elevation of iodide supply or of a single administration of a high dose of inorganic iodide in the presence of autonomously functioning thyroid tissue. Prolonged elevation of iodide supply in regions of iodine deficiency will cause manifest hyperthyroidism in many cases of thyroidal autonomy (cases with facultative hyperthyroidism).

Clinical significance of endogenously labelled thyroid hormones in the diagnosis of thyroidal autonomy.

The clinical value of the determination of 123I concentration in serum 48 hrs after tracer administration (123I)48 is investigated with special regard to thyroidal autonomy. Serum radioiodine concentration, thyroid radioiodide uptake at 4 and at 48 hrs were measured in 74 healthy subjects and patients with simple goiter, in 36 patients with thyroidal autonomy (diagnosis by thyroid suppression test), and in 20 hyperthyroid patients. 83% of the patients with elevated radioiodine concentration belonged to the group of thyroidal autonomy.

[Determination of the serum concentration of radioiodine with 123I].

Though the half-life of 123I is much shorter than that of 131I, the determination of the radioiodine concentration 48 hrs after tracer administration (123I)48h can be done with the same precision. This precision is achieved by the fivefold dose given to the patient and the fourfold specific count rate. In 36 euthyroid patients with thyroidal autonomy the 123I concentration in serum was determined 48 hrs after tracer administration and was compared with the values obtained in a control group (n = 74).

Thyroid hormone concentrations in dialysate during hemodialysis in children.

Thyroxine (T4) concentration in dialysate in the course of hemodialysis was determined in 15 children. Concentrations were measured by a modified radioimmunoassay. During hemodialysis there was a slight increase in T4 concentration.