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During evaluation of cardiac function using 99mTc human serum albumen (functional scintigraphy during contraction of the left ventricle), it is necessary to take account of the background radiation which is derived from the lungs and great vessels overlying the heart. Only after correction of the background radiation is it possible to evaluate the severity of various types of cardiac insufficiency; this can be obtained by integrating the impulse during systole and subtracting this from the impulse rate over the left ventricle during a complete cardiac cycle. Apart from the background correction derived from the systolic-diastolic variation, it is necessary to obtain adequate resolution by examining 100 frames per second, an adequate picture matrix (4-K) in order to obtain adequate spacial resolution and accurate measurements of systole and diastole. The latter should be obtained not from the E.C.G., but directly from the volume curve of the left ventricle as determined by the isotope method.

Radio-active plastic microspheres with an average diameter of 15 mu were used in eight dogs to measure renal perfusion and the results compared with time-activity curves before and after constriction of the left renal artery. It was shown that the values obtained for renal blood flow by functional scintigraphy are not accurate, particularly for moderate or low blood flow. The reason for this is primarily the distortion of the intravenously injected radio-active bolus and the consequent deviation from the so-called delta function.

Although the clinical picture of autonomous adenoma of the thyroid gland has been well known for a long time, a series of connections has in some cases been unclarified, and in other cases contradictory so far. This applies in particular to the relationships between the scintigraphic image and the metabolic balance of the autonomous adenoma. In 98 patiets aged from 21 to 70 years old (80 women, 18 men) with autonomous adenoma unequivocally verified by suppression or stimulation test, it was therefore investigated whether such connections can be demonstrated. The following could be established: 1. In patients with an autonomous adenoma, there is an established connection between the scintigraphy image, the thyroxine and triiodothyronine levels in the serum as well as the delta-TSH. In patients with scintigraphically compensated autonomous adenomas, the hormone levels are all in the euthyroid range. In patients with scintigraphically decompensated autonomous adenoma, the values of thyroid hormones are found in some cases in the euthyroid, and in other cases in the hyperthyroid range. 2. Scintigraphically decompensated autonomous adenomas always display a negative TRH test, whereas this may be negative and in other cases also postivie in scintigraphically compensated autonomous adenomas. The TRH test may be negative in compensated and in decompensated autonomous adenoma even in patients in whom the thyroid hormone values in the serum are in the euthyroid range. The TRH test thus does not permit evaluation of the current functional activity of the autonomous adenoma. It is furthermore unsuitable for delimitation of a compensated from a decompensated autonomous adenoma as well as for different diagnosis between a nodular goiter and a scintigraphically compensated autonomous adenoma. 3. There is a statistically established relation between the size of the autonomous adenoma, the age of the patient as well as the thyroid hormone values. Autonomous adenomas accordingly become larger with increasing age. The values of thyroid hormones increase and lead to corresponding alterations in the TRH test.

In 31 patients with histologically proven hepatocellular jaundice hepatobiliary scintigraphy with Tc-99m labelled IDA derivatives was performed. Results were classified under morphological (demonstration of liver parenchyma, ductus choledochus, bile ducts, gallbladder, kidney) and functional (Tmax, half time of bile excretion, appearance of activity in ductus choledochus, gallbladder, and intestines) criteria. The liver parenchyma could be demonstrated in 90.3% of cases, ductus choledochus in 71%, and the gallbladder in 72.4%. The type of tracer excretion into the intestines showed 9.5% activity accumulation in the gallbladder with late bile excretion into the intestines and 90.5% early activity excretion into the duodenum with late filling of the gallbladder. The intrahepatic bile ducts were demonstrated in 22.6% (left hepatic duct) and 6.5% (right hepatic duct). In 35.5% of cases the kidneys were still visible after 15 min p.i. All cases showed - sometimes delayed - bile excretion into the GI tract. The time of appearance of activity in ductus choledochus (18.4 min) and gallbladder (39.5 min) was delayed. The liver histogram showed likewise delayed values concerning Tmax (14.3 min) and half life of tracer excretion (greater than 30 min) when compared to controls. The differentiation of hepatocellular jaundice from obstructive jaundice is possible by the demonstration of bile excretion into the intestines, normal width of the bile ducts, and filling of the gallbladder.

A retrospective study of 101 patients with histologically confirmed cirrhosis of the liver and portal hypertension was carried out in order to evaluate the accepted scintigraphic criteria. In only 20% were all the essential criteria present. The absence of generally accepted important scintigraphic signs does not exclude the diagnosis of cirrhosis of the liver. Specificity of liver scintigraphy in cirrhosis of the liver is fairly low, but sensitivity of the method is almost 100%.