Differential renal uptake of 201Tl: requirements for acquisition, display and quantification.

Renal uptake of 201Tl may have a role in screening for renal asymmetry in hypertensive patients (HP) who are referred for myocardial scintigraphy. The qualitative aspects of digitized planar images, and quantified differential renal uptake (DRU) of 201Tl were rated by comparing a simple technique (S) for outlining each kidney with an interpolative background subtracted technique (IB). These parameters were assessed in an initial series of patients by varying the length of acquisition (from 1 to 5 min), delay in acquisition (from 10 to 210 min after injection), and image preparation (nine-point smoothing). Six blinded observers rated the quality of coded images. Image quality was improved (P less than 0.01) by increasing the length of acquisition to at least 2 min, by smoothing of the images and by imaging within 2 h of 201Tl injection. Variability in quantification of DRU was suboptimal with acquisition for only 1 min and was more adversely affected with S than with IB. Clinical application of the quantitative technique was assessed in 180 HP and 32 normotensive controls. With IB, the normal range for DRU was slightly greater than for S. The two techniques were comparable in identifying abnormal cases and found 21 +/- 3% (S) and 19 +/- 3% (IB) of HP as lying outside the normal 99% confidence interval. Both quantitative techniques showed excellent agreement with renal angiography (n = 24). Furthermore, preliminary experience with surface markers and with 180 degrees tomography suggests the potential for simultaneous correction for renal depth. These data justify the use of adjunctive renal imaging during myocardial scintigraphy with 201Tl.

Demonstration of renal varices using technetium-99m red blood cells in the investigation of recurrent macroscopic hematuria.

A case of severe, recurrent, macroscopic hematuria in which the diagnosis of renal vein varices was suggested by Tc-99m red blood cell blood pool imaging is described. Current diagnostic modalities are discussed and an integrated use of this test is proposed.

Spontaneous resolution of severe right ventricular dysfunction in right ventricular infarction: documentation by radionuclide studies.

A case of inferior myocardial infarction complicated by severe arrhythmias and right heart failure is presented. Radionuclide studies performed near the acute phase and one month later illustrate the reversibility of right heart dysfunction caused by infarction. Signs of right ventricular involvement in acute inferior myocardial infarction are noted in about 40% of cardiac blood-pool studies: right ventricular dilatation with a significantly decreased ejection fraction, and ventricular wall motion abnormalities. Follow-up studies in the recovery period show good recovery of right ventricular function.

Lipid peroxidation in the newborn rat: influence of fasting and hyperoxia on ethane and pentane in expired air.

The rate of lipid peroxidation, as determined by expired air pentane and ethane measurements, was assessed in suckled or fasted newborn rats exposed to air or hyperoxia (FIO2 greater than 0.95). Pentane and ethane production in suckled newborn rats did not significantly change with exposure to hyperoxia after birth. Pentane production averaged over a 3-day exposure period was 2.8 pmol/100 g/min in hyperoxia versus 2.5 pmol/100 g/min in air. However, significant increases in ethane production occurred in fasted newborn rats over the first 18 h of life (less than 2.5 pmol/100 g/min increasing to greater than 6 pmol/100 g/min), which were not observed in suckled animals. Although hyperoxia did not cause an increase in pentane or ethane production above air-exposed controls, nutritional deprivation in newborn rats appeared to accelerate lipid peroxidation events and resulted in high mortality in newborn rats exposed to hyperoxia.