Radioisotope (RI) is widely applied inthe various. fields of basic medicine as well as clinical practice.
Recently newer isotopes and improvement in measuring devices have been developed. Thus, RI became one of the new laboratory items. Hemodynamic studies of various organs and peripheries have been relied mainly upon biological or biochemical methods up to lately. However, the procedure is not simple by the conventional methods which prevented clinical application. Since the medical application of radioisotope was introduced, a new horizon was_ opened in this field with clinic research for laboratory methods.
The author reported the results of the hemodynamic studies of various organs using radioisotope at our RI laboratory for the past ten years.
As shown in the Tables & Figures, the formula and radiocardiogram were used in the measurement of cardiac output, hepatic and renal plasma flow utilizing radioisotope.
In the past, Fick´s method and dye-dilution technique were used for measuring cardiac output. These methods required rather complicated procedures and clinical implication was not easy.
When radiocardiogram was measured with radioisotope such as RIHSA we could measure them simply and with accuracy. In the 11 patients with heart diseases a comparison was made with Fick´s method to determine reiiiability of radioisotope method. Correlation coefficient "r" between these two methods was 0.967, being quite compatible.
Renal plasma flow was measured by the method of Razzak et al. appyling ^(131)I-hippuran. The reproducibility was determined as in the Table 2. Average variability was O.6% which means the method was comparatively reliable. Normal values of renal plasma flow in the Korean adults were 582±50m1/min/1. 73m.
Hepatic blood flow:
There is no simple and precise way to measure hepatic blood flow at the present time. However, effective or so-called minimal hepatic blood flow could be obtained from measuring plasmadisappearance time utilizing colloidal radio-substance. This method is rather easy to perform and clinically applicable.
In the measurement of plasma disappearance time, when the blood sample count and external count are compared, as shown in Fig.5, correlation coefficient, "r" is 0.815. This means that the external counting alone without blood drawing is sufficient for the measurement.
Material and Results
I Cardiovascular System
1) Essential hypertension
The various cardiac hemodynamic indices in the patients with essential hypertensive heart disease are as in Table 4.
When compared with control group, cardiac output, cardiac index, stroke volume, stroke index and plasma volume revealed no difference.
However, peripheral resistance was elevated.
The effect of antihypertensive drugs on the hemodynamics was observed. The results of the hemodynamic values before and after the administration of chlorothiaand reserpine are shown in the Table 6.
There were significant decreases of plasma volume, cardiac output and renal plasma flow after the chlorothiazide, while using reserpine no hemodynamic changes were noted except for the reduced pulse rate in Table 7.
2) Cardiac Disease
The observed results of hemodynamic changes in the patients with various valvular heart diseases are shown in Table 8, Fig. 6.
The measured data of 39 cases fall into class I showed no significant difference compared with the control group.
In the 17 cases of congestive heart failure there was definite reduction in cardiac output and cardiac index.
When the hemodynamic changes were observed before and after the digitalization in 9 patients with congestive heart failure, there was a significant decrease of cardiac output.
3) Hyperthyroidism
The hemodynamic changes seen in the patients with hyperthyroidism before and after the treatment are shown in the Fig. 7, 8.
Ⅱ. Liver Disease
1) Hepatic blood flow; blood disappearance rate of ^(198)Au colloid:
The hepatic blood flow was measured in the patients with cirrhosis of the liver, hepatitis and gallbladder diseases. For the measurement ^(198)Au-colloid was used.
In the cases with cirrhosis of the liver, there were significant differences of T½ and K-value compared with the controls.
The prolonged T½ seen in the patients With cirrhosis of the liver was considered to be caused by marked red of effective hepatic blood flow. There was close relation between severity of the cirrhosis and T½ prolongation, which in the cases of acute hepatits or obstructive jaundice T½ remained within normal ranges and hepatic blood flow unchanged. In the group with liver cirrhosis, T½ of 198Au-colloid had a significant reversecorrelation with values of serum albumin.
2) Hemodynamic study in the patients with liver cirrhosis:
The hemodynamic changes observed in the patients with liver cirrhosis are shown in Fig. 10.
The plasma volume was markedly increased and cardiac output and cardiac index were also increased to some extent. Ccr was reduced significantly. When the comparison was made between response group and resistant group according to severity of ascites and reponse to diuretics, in the latter group there was decreasing tendency of cardiac output and plasma volume with a maked reduction of renal blood flow (Fig. 11).
Renal plasma flow was observed in two groups with Ccr abobe 60ml/min/1.73m and below 60ml/min/1.73m.
In the latter group there was a definite decrease in renal plasma flow (Fig. 12).
These findings suggest an increased resistance of renal afferent arteriole which may cause a reduced renal plasma flow.
Renal circulatory impairment observed in the patients with cirrhosis of the liver tended to precede well before the azotemia or oliguria.
Ⅲ. Renal Disease
Acute renal failure is one of the unique findings in Korean hemorrhagic fever which is an endemic disease in Korea.
The results of hemodynamic changes determined during oliguri: and diuretic stages are shown in the Table 9,10.
In the oliguric stage, both renal plasma flow and filtration fraction were reduced markedly, and in the diuretic phase, renal plasma flow was reduced while there was increased filtration fraction.
In the patients with chronic renal failure, the renal hemodynamic changes were compatible with those observed during the oliguric phase of the acute renal failure.
Thus, reduced urine volume in the oliguric stage of acute renal failure is caused by intrarenal mechanism rather by the decreased renal plasma flow.
Sequential Scintiphotography of Various Organs by Scinlri-camera
With an Anger camera, a dynamic rather than a static observation of the scan is possible. Thus, one could observe the absorption, uptake and excretion of any injected radioisotope in a target organ with a time sequence. Author observed the blood flow of various organs by sequential scintigraphy with serial scans with ^(131)I-Rose bengal, t9$Au-colloid and 89mTc-pertechnetate.
The results shown in the Fig. 14, 15.
Fig. 14. shows the scintigram of the normal liver and gallbladder. Fig. 15. is the scintigram of the patients with cirrhosis of the liver and obstructive jaundice. The scan was done with 10 to 15 Minutes interval. In normal persons gallbladder visualization began with average 29 + 5.7min. and intestinal phase was observed at about 54 min.
Cardiac Blood Flow Study
Recently the radionuclides with a short half-life such as ^(99m)Tc have been developed, which can be given to the patients in large amount without any risk. With these radionuclides, the changes of blood flow in the organs can be determined in the fairly short period of time. Cardiac sequential scintiphotogram was performed in the-patients with pericarditis andtetralogy of Fallot as well´ as in the normal persons to confirm clinical application.
Fig. 16. shows sequential scintiphotogram of a normal person. A bolus of ^(99m)Tc is injected and after 1.5 to, 3.0 sec. right atrium is appeared through superior vents cava and then right ventricle. In 3.0 to 4.5 seconds, an injection to pulmonay artery via right ventricle is. observed and 1 to 2 seconds later a portion of left atrium and left ventricle are seen. In 7.0 to 9.0 seconds, left ventricle and ascending aorta are seen well.
Fig. 17. is that of a patient with tetralogy of Fallot. The left ventricle normally appeared in 4.5 to 6.0 seconds appears before 4 seconds at the same time with. appearance of pulmonary artery shadow.
This suggests a right to left shunt.
These findings suggest the possibility of diagnosing congenital heart diseases and obstructive vascular disease without such complicated procedures as a cardiac catheterization.
Rapid Sequential Cranial Scintiphotography
Since most of the focal intracranial lesions are either the results of vascular diseases or those of abnormal vascular component, arteriographic characterization is, widely applied, to determine the vascular nature of the lesions for diagnosis and treatment.
With Anger-type scintillation camera using a near-ideal nuclides such as ^(99m)Tc anatomic delineation anal visualization of vascular structure has been throughly confirmed.
Rapid sequential scintiphotogram was carried out by passing ^(99m)Tc pertechnetate bolus through this system. About 1. mCi of ^(99m)Tc-pertechnetate was rapidly injected. The vascular phase in the normal persons are as follows (Fig. 18). Early filling of major neck artery is appeared 3.5 to 7.0 seconds after injection. The major neck and cerebral artery are seen 7.0 to 8.5 seconds.
The filling of cerebral artery and cappillary which means diffuse distribution of activity in the cerebral hemisp here, is appeared 8.5 to 10 seconds after the injection. The cerebral capillary filling and early venous filling usually is appeared at 11.5 to 13 seconds. After one to two minutes, intracranial activity is mainly confined to major vascular structures. These static scintiphotography is also observed. after 15 minutes and one hour. The rapid sequential scintiphotogram of a patient with right hemispherectomy undergone in 1957 showed no early vascular phase, however, after 15 minutes´ static scintiphotogram a hot lesion appeared (Fig. 19).
It is considered due to compensated collateral vasculand abnormality of brain barrier.
This technique provided data of vascular characterization which cannot be detected with brain scanning or cerebral angiography. Besides, the technique also has advantage of simplicity and rapidity of the procedures.
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