Quantitative gallbladder imaging following cholecystokinin.

Quantitative gallbladder imaging with Tc-99m paraisopropylimidodiacetic acid (PIPIDA) was performed and time-activity curves over the gallbladder were obtained following i.v. injection of cholecystokinin (CCK). The gallbladders that failed to contract after CCK were found to be abnormal at surgery. This test appears to be helpful in evaluating patients who have normal oral cholecystograms but have persistent symptoms of gallbladder disease.

A quantitative clinical comparison of three 99mTechnetium labeled brain imaging radiopharmaceuticals.

In a comparison study of three commonly employed 99mTc brain imaging pharmaceuticals, 16 patients with proven brain lesions had imaging performed with DTPA, glucoheptonate, and pertechnetate over a short interval of time. Lesion detectability was assessed by a data processing system which evaluated average lesion-to-background activity ratios for each patient examination. Statistical analysis of the resultant data demonstrated a significant improvement (20%) in lesion-to-background ratio in favor of one hour delayed DTPA images versus two hour delayed pertechnetate images. Comparison of one hour delayed DTPA images with one hour delayed glucoheptonate images did not reveal a significant difference in lesion-to-background ratio. The authors conclude that both Tc-DTPA and Tc-glucoheptonate are superior alternatives to pertechnetate when employed in the manner described.

The value of bowel preparation in Ga-67 citrate scanning: concise communication.

In order to assess the value of bowel preparation in Ga-67 citrate scanning, we retrospectively analyzed 156 randomly selected 72-hr Ga-67 scans and compared the extent of bowel activity in two groups of patients: those receiving a vigorous 3-day bowel preparation and those receiving no preparation. The populations were studied with regard to age, sex, and bowel preparation. A three-way analysis of variance (prep X sex X age) revealed no influence of these parameters on the degree of colonic gallium activity. We conclude that bowel preparation as used at our institution did not seem to reduce colonic gallium content significantly (p greater than 0.10).

Noninvasive experimental determination of the individual kidney filtration fraction by means of a dual-tracer technique.

A noninvasive method for measurement of the individual kidney filtration fraction (FF) is presented, based on an analysis of the early rise of the kidneys' time-activity curves obtained after simultaneous injection of tubular [131I] ortho-iodohippurate and glomerular (Tc-99m DTPA) tracers. The analysis is based on the assumption that an insignificant amount of tracer leaves the kidney during the first few moments following injection. Therefore the kidney activity during this period is directly proportional to the integral of the blood (heart) activity. The dual-tracer technique allows the direct calculation of the ratio of glomerular to tubular clearances, i.e., the FF. In vivo studies were performed on 12 dogs, including normals as well as others with acute ureteral ligation or Benemid-induced tubular blockade. The calculated FF correlated well with the FF obtained from single-shot clearances performed simultaneously. We conclude that the FF can be calculated directly for each kidney, noninvasively, from the early part of the tubular and glomerular time-activity curves by noninvasive external detection.