No abstract

Since the recording of the renal count rates in the anterior and posterior views permits an accurate determination of the split renal function, the GCM yields reliable estimates also of the single kidney GFR.

In radionuclide cerebral angiography (RCA) the analysis of the activity-time curves recorded over the hemispheres following an intravenous bolus injection of a radioactive indicator permits the evaluation of absolute cerebral mean transit times (MTTcb). The inverse of MTTcb is an index of cerebral blood flow. The bolus parts of the cerebral activity curves were fitted with gamma-variate functions. The duration of the injection bolus and its subsequent dispersion through the cardiopulmonary circulation were corrected for using the activity curve over the aortic arch. In a control material of 52 subjects MTTcb was uncorrelated with age and equal to 3.2 +/- 0.67 s (means +/- 1 SEE) for the 37 subjects younger than 60. For the fifteen subjects older than 60, mean MTTcb showed a steep increase with age. The results were in close agreement with those obtained by other researchers using either correction of cerebral curves based on a physical flow model or direct injections into the internal carotid artery. Comparison of RCA with x-ray carotid angiography in 12 subjects was satisfactory. Repeated RCA examinations in nine subjects a few days apart yielded a reproducibility of 0.7 s for MTTcb. The RCA is non-invasive, rapid, easy to perform and without risk for the patient. The RCA is recommended for quantitative evaluation of major alterations in cerebral perfusion.

The blood volume can be measured after labelling of red blood cells with technetium-99m. In addition, the blood volume and its standard error of estimate can be calculated from the subject's sex, height and deviation from desired weight. By comparing the measured blood volume with the estimated normal blood volume and using a statistical test, it can be decided whether a measured blood volume is normal or not. This method was applied to a group of 36 patients with heart diseases. Four of the patients had abnormal blood volumes. In the remaining 32 patients the measured blood volumes were equally distributed around the estimated mean normal values. The method described for determination of normal/abnormal blood volumes can be considered a by-product of routine radionuclide cardiography.

Indirect radionuclide renocystography (IRRCG) is a method for the detection of vesico-ureteral reflux by analysis of the activity-time curves over the kidneys and bladder during voiding of urine about 30 min after intravenous administration of a radioactive indicator. This paper presents a new method for detection of reflux by a statistical test, the magnitude of the reflux is evaluated by the reflux volume per 1.73 m2 body surface area. Residual urine volume and urine voiding efficiency are also calculated. In a retrospective study of 154 children examined for renal and urological diseases consisting mainly of urinary tract infections, vesico-ureteral reflux was found by IRRCG in 16% of the kidneys (23% of the children). Reflux volumes were below 10 ml/1.73 m2 in 90% of the children with reflux. The mode value of the reflux volume was 2 ml/1.73 m2. For a subgroup of 97 children, the results were compared with micturating cysto-urethrography (MCU). This showed that a negative IRRCG in conjunction with the renal mean transit time of the radioactive indicator determined by gamma camera renography could be used as a screening test for vesico-ureteral reflux when MCU was considered a true reference method. Hence, about 75% of the invasive and high radiation dose MCU can be replaced by the non-invasive and low radiation dose IRRCG. The discrepancies between the two methods and the reasons for them are discussed.