Among all the physiological indices that can be quantified using renography, measurement of renal function is the most basic. These measurements are used to make critical clinical management decisions and, as such, their reliability needs to be quality assured. This article seeks to address each aspect of the renography procedure, with particular emphasis on the effect on measurement of relative renal function. Estimation of individual kidney function is mentioned, but only briefly. A consensus approach was adopted, overseen, and directed by a chairman appointed by the Scientific Committee of the International Radionuclides in Nephro-Urology Group. The chairman selected the panel of experts from eight different countries based on their practical experience in the field. Where evidence exists to support the various recommendations it is given. Otherwise, the stated guidance represents the considered opinion of a body of experts, based on long experience and unpublished data. Same necessary compromises were made to account for the fact that renography is seldom performed solely with the purpose of measuring relative renal function. The technicalities of renography have always been a source of debate in nuclear medicine, which is reflected by the fact that a consensus could simply not be reached on a small number of issues. The structure of the report ensures that these are clearly indicated. This should serve to highlight gaps in our current knowledge, thus helping to direct future research. it is envisaged that the recommendations will be revised on a P-year cycle to ensure that they remain up to date. An "open" process will be used to encourage participation and ownership. It is hoped that promotion of these guidelines, suitably complemented by audit processes, will raise standards in the practice of gamma camera renography. Copyright (C) 1999 by W.B. Saunders Company.

Three clinically unsuspected malignant pericardial effusions were discovered during routine dynamic hepatic scintigraphy. The only common clinical feature shared by the patients was dyspnea. Static scintigrams alone would not have detected these effusions, which points out again the importance of including dynamic scintigraphy in routine radionuclide evaluations of the liver.

An island of bone marrow surrounded by the glue used in securing a hip prosthesis accumulated In-111 leukocytes in a patient being imaged for hip pain. This was shown to be normal marrow uptake of labeled cells and not an abscess by performing bone marrow imaging. The appearance of the leukocyte and bone marrow scans of the area were identical.

Decreasing splenic activity occurred during the maximum exercise phase of gated stress testing in 24 patients who underwent 26 such studies. This event was related to increasing exercise, and correlated with the relative increase in heart rate, pulse-pressure product, and cardiac output, but not ejection fraction. A multiple linear regression analysis showed that the combination of increases in pulse-pressure product and cardiac output had the best correlation with decreasing splenic activity at the conclusion of exercise. Redistribution of cardiac output toward muscle and away from splanchnic viscera is a consequence of exercise, and is graphically demonstrated by decreasing splenic visualization, which in some patients was so marked as to result in disappearance of the organ from the video monitor.

The logarithmic relationship of serum creatinine and creatinine clearance was analyzed in 100 adult patient studies using a geometric regression technique. Each sex was independently analyzed, and the subsequently derived regression formulae were age corrected resulting in mathematical models useful in estimating creatinine clearance from serum creatinine concentrations. These formulae were tested prospectively in another group of 100 patient studies in which creatinine clearance had been determined, and the results compared to values derived by use of two other published formulae. This newer method resulted in a closer distribution of data around a line of identity compared to other formulae and allowed for a good "bedside" estimation of creatinine clearance from serum creatinine concentration.

The fractional renal uptake of intravenously administered Tc–99m DTPA, within 2 to 3 minutes following radiotracer arrival in the kidneys, is proportional to the glomerular filtration rate (GFR). Thus it is possible to determine total, as well as individual kidney, GFR by a radionuclide technique which needs only six minutes of patient time and requires neither blood nor urine samples. The radionuclide computed GFR correlates extremely well with 24–hour creatinine clearance determinations, and is highly reproducible. This method has been used in nearly 500 split renal function determinations and has provided valuable, accurate information.

99mTc diethylenetriaminepentaacetic acid (stannous) is cleared from the blood by glomerular filtration. However, calculation of the glomerular filtration rate has required analysis of serial blood samples drawn over intervals of several hours in order to determine the radionuclide clearance rate. This lengthy procedure can be circumvented by the direct scintigraphic determination of fractional radionuclide accumulation within each kidney, occurring at a specified time interval after radionuclide administration. This value has been correlated with 24 hr creatinine clearance values in a group of hospitalized patients. From these data, a formula was derived allowing for estimation of total glomerular filtration rate, as well as individually for each kidney, without requiring blood samples. This procedure needs only 6 min of patient time.

Thirty-three children who had strokes were studied by dynamic and static scintigraphy, 29 by CT scanning, and 10 by cerebral angiography. The accuracy of dynamic scintigraphy in stroke detection during the first week of clinical symptoms was 94% while CT scanning was 60% accurate and static scintigraphy 11% accurate. During the second week the accuracy of CT scanning increased to 100%, but static scintigraphy improved to only 50%. Fifty percent of scintiangiograms performed during the first week showed either luxuriant perfusion or flip-flop patterns. In some patients these two flow patterns changed to that of cerebral hemispheric ischemia after going through a phase during which perfusion appeared to be equal in the two hemispheres. Dynamic scintigraphy is believed to be the test of choice for stroke detection in children during the first week.

The various urologic abnormalities for which ultrasonography can be a valuable diagnostic tool are discussed, including renal masses, nonfunction of the kidney, and abnormalities of the lower urinary tract. Ultrasonography is a useful adjunct to radionuclide imaging, intravenous urography, and renl angiography, and is particularly well suited for the pediatric population.

Of 33 children with various cholestatic syndromes who were studies with sonography, 19 also had 131I rose bengal scintigraphy, and 12 also had 99mTc sulfur colloid scintigraphy. Patients were categorized into intra- or extrahepatic etiologies for their cholestasis. Of 19 children in the extrahepatic category, 17 had abnormal sonographic studies; two with biliary atresia appeared normal. All 14 patients in the intrahepatic category had normal sonographic studies. Rose bengal was most useful when demonstrating biliary patency. Some cases of biliary atresia with normal sonography and lack of rose bengal excretion into the intestinal tract could not be separated from cases of neonatal hepatitis using a similar combination of studies. Radiocolloid studies were less valuable than other examinations except when demonstrating diffuse hepatic reticuloendothelial dysfunction as found in two cases of congenital syphilitic hepatitis.

Gray scale ultrasonography, arteriography and excretory urography were done in 17 children with Wilms tumor. The results of these studies were correlated with the pathological specimen. At the time of operation 71 per cent of the tumors were necrotic. Ultrasonography predicted correctly the internal consistency of Wilms tumors in 94 per cent of the cases, while arteriography was 64 per cent and excretory urography was 41 per cent accurate. This information regarding neoplastic degeneration added to the completeness of the radiographic examination and forewarned the surgeon of a potentially difficult resection.

Sixty-three patients with glycogen storage disease were evaluated. Findings on plain film examinations, excretory urography, barium gastrointestinal studies, ultrasonography, and angiography were categorized by type of glycogen storage disease. In type I findings include hepatomegaly with hepatic dysfunction, renomegaly with an increased incidence of renal calculi, and osteopenia with various associated osseous abnormalities. These changes were less pronounced in types III, IV, and VI. Type II displayed either cardiac or skeletal muscle glycogen deposition. Correlation with postmortem examination in 14 individuals is given.

Nine children with arteriovenous malformations (AVMs), and a tenth with a cerebral aneurysm, had computer-processed dynamic scintigraphy with static scintigrams, transmission computed tomography (CT) both with and without contrast injection, and radiopaque cerebral angiography. All ten lesions were detected by dynamic scintigraphy and angiography, whereas two AVMs were missed on CT scans and the aneurysm and two AVMs (one missed by CT) were not identified on static scintigrams. Time-activity curves generated from regions of interest placed over the cerebral hemispheres, AVMs and/or various venous structures permitted, respectively, estimation of interhemispheric partition of perfusion, estimation of the fraction of total cerebral hemispheric perfusion preferentially directed into a malformation, and indication of the route of venous drainage from the lesions. While dynamic scintigraphy and CT scanning both identified the aneurysm, scintigraphy was the most effective screening test for detecting AVMs owing to its accuracy, lower cost, and lack of required anesthesia, heavy sedation or iodinated contrast agents.

The echocardiographic and perfusion scintigraphic evaluation of an adolescent boy with a pulmonary arteriovenous fistula is reported. Contrast echocardiography following the rapid intravenous injection of indocyanine green dye was utilized to document extracardiac right-to-left shunting. Perfusion lung scintigraphy demonstrated the presence of a single large pulmonary arteriovenous fistula. Contrast echocardiography and perfusion scintigraphy are minimally invasive, safe and easily performed techniques for the rapid diagnosis of pulmonary arteriovenous fistula.

Forty-three children with intrahepatic masses had technetium Tc 99m sulfur colloid hepatic scintigrams including scintiangiography. Hypervascularity occurred in nearly one third of the masses, but was limited to children with primary liver tumors including hepatomas, hepatoblastomas, hepatic adenomas, and cavernous hemangiomas. All metastases, abscesses, and hematomas were hypovascular. Routine inclusion of scintiangiography may allow separation of primary hypervascular liver tumors from other hypovascular masses whose static hepatic scintigrams are virtually identical.

Renovascular disease often leads to hypertension in children. The most frequent cause is fibromuscular dysplasia of focal type affecting main and peripheral arteries. Diastolic readings in excess of 110 mm Hg with normal serum creatinine and urinalysis are suggestive of renovascular disease. Excretory urography was positive in 65% of patients with unilateral disease. Radionuclide scans complement a positive excretory urogram but may be positive when the urogram is negative. Plasma renin activity was raised in the majority of patients; if the patient does not have peripheral branch stenosis, the renal vein renin ratio will lateralize in unilateral renal disease. The overall results of surgery are encouraging: 86% of surgical procedures alleviated hypertension in unilateral disease.

A two-month-old girl with congenital syphilitic hepatitis had bizarre liver scintigraphic features showing diminished hepatic uptake of radiocolloid with accentuated pulmonary and bone marrow accumulation. These features were reversible following penicillin therapy and to our knowledge are previously undescribed manifestations of this multisystemic disease.