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Evaluation of solid phase radiolabels of dog food for gastric emptying.

99mTc-Pertechnetate, 99mTc-mebrofenin, 99mTc-disofenin, 99mTc-sulfur colloid, and 99mTc-Dowex resin beads were evaluated for in vitro stability as a label for both dry extruded, and canned dog food for gastric emptying scintigraphy. A sample of each radiolabeled diet was added to water, gastric juice, intestinal juice, or gastric juice followed by intestinal juice for in vitro digestion. After a 3-hour digestion period, tubes were centrifuged and percentage solid phase retention (%SPR) was calculated. The experiment was repeated three times over a 14-day period to minimize day-to-day variation. For dry dog food, 99mTc-mebrofenin and 99mTc-disofenin had similar %SPR in water (96 and 93%, respectively) and gastric juice (>95% each) and were significantly higher than other labels. For canned dog food, mebrofenin had a 91% SPR for the water or gastric juice digestions, and 99mTc-Dowex had a %SPR of >99%. 99mTc-mebrofenin and 99mTc-Dowex were also tested in vivo, where 99mTc-Dowex had poor stability, and 99mTc-Mebrofenin had excellent stability. 99mTc-Mebrofenin is a suitable label for dog food for gastric emptying scintigraphy.

Analysis of Variance↗

Nebulized interleukin 2 liposomes: aerosol characteristics and biodistribution.

Although interleukin 2 (IL-2) has been associated with modest anti-tumour responses in man, treatment-related toxicity has limited its widespread use. The local delivery of liposomal formulations of interleukin 2 to the lung as aerosols has been demonstrated to be non-toxic, biologically active, and associated with regression of spontaneous pulmonary metastases in dogs. This study was undertaken to evaluate the physical and biological characteristics of nebulized interleukin 2 liposomes. The aerosol droplet size distribution and the physical stability of interleukin 2 liposomes were examined in-vitro using an Andersen cascade impactor and studies of liposome entrapment of interleukin 2 before and after nebulization. The biological stability of interleukin 2 liposomes after nebulization was demonstrated using the CTLL-2 bioassay for interleukin 2. In-vivo studies of pulmonary biodistribution and clearance of inhaled technetium (99mTc)-labelled interleukin 2 liposomes were undertaken in a normal dog. Aerosols of free interleukin 2 and of interleukin 2 liposomes were compared in both in-vitro and in-vivo experiments. The mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD) of interleukin 2 liposomes were 1.98 microns and 2.02, respectively. Independent analysis of aerosol particle-size distribution using the constitutive components of the interleukin 2 liposomes (interleukin 2: lipid:HSA) demonstrated a close correlation of size distributions (r = 0.9445; P < 0.001). The entrapment of interleukin 2 in liposomes was 93 +/- 4.3% before nebulization and 90 +/- 8.9% after. After delivery to an anaesthetized dog, interleukin 2 liposome aerosols were deposited evenly throughout the lung (mean +/- s.d. central lung-to-peripheral lung deposition was 1.12 +/- 0.03). After approximately 24 h inhalation, interleukin 2 liposomes were retained within the lung and were taken up in part by the spleen. The results of this study are indicative of the stability of this interleukin 2 liposome formulation to nebulization. Such nebulization might be an attractive immunotherapeutic strategy for treatment of pulmonary metastases and primary lung cancers.

Aerosols↗

The prelaparotomy diagnosis of extrahepatic biliary atresia.

The diagnostic accuracy of laboratory investigations in the prelaparotomy differentiation between extrahepatic biliary atresia (EHBA) and intrahepatic disease (IHD) was assessed in 86 consecutive infants presenting with conjugated hyperbilirubinaemia. Forty five infants had EHBA and 41 IHD. The mean serum bilirubin concentration, gamma-glutamyltranspeptidase (GGT) activity, and the GGT/aspartate transaminase (AST) ratio were appreciably higher in infants with EHBA than in those with IHD. In infants with IHD, however, serum bilirubin concentrations were in the EHBA range in 19 (47%), as were GGT values in 29 (71%), and GGT/AST ratios in 33 (80%). In individual patients neither increasing nor decreasing GGT values were of diagnostic importance. Failure of biliary excretion of 99Tcm-p-Butyl-ida occurred in 29 of 30 (97%) patients with EHBA but also in 22 of 23 (67%) with IHD. In all 5 patients with IHD associated with alpha 1 antitrypsin deficiency these 4 investigations gave results in the EHBA range. Liver biopsy specimen interpretation, correct in 38 of 42 infants with EHBA, gave an overall accuracy of diagnosis of 86%: the results of 3 further biopsies were equivocal. In 33 of 40 infants with IHD bile duct obstruction was excluded; the remaining 7, including 4 with alpha 1 antitrypsin deficiency, showed equivocal changes. Faecal excretion of 131I rose bengal faecal excretion was less than 10% in 36 of 37 patients with EHBA and in 9 of 26 with IHD, giving an overall accuracy of diagnosis of 84%. In patients in whom genetic disorders, such as alpha 1 antitrypsin deficiency had been excluded, interpretation of liver biopsy specimens together with 131I rose bengal faecal excretion remain the most accurate means of identifying those who need surgery for EHBA and of avoiding unnecessary laparotomy in infants with IHD.

Aspartate Aminotransferases↗

99mTc dimercaptosuccinic acid (DMSA) scan in patients with established radiological renal scarring.

The findings on 99mTc dimercaptosuccinic acid (DMSA) scans were examined in 54 patients aged 3 to 33 years in whom renal scarring had been diagnosed radiologically in childhood after urinary tract infection. There was no recent history of infection. Vesicoureteric reflux had been present in 48 patients and had stopped in 23 at the time of the DMSA scan. In six of the 72 radiologically scarred kidneys, the DMSA scan appeared normal but scarring would have been overlooked in only two of the 54 patients. DMSA scan changes are non-specific and underestimated individual scars in 21 kidneys. The intravenous urogram and the DMSA scan showed good correlation but should be regarded as complementary investigations in these patients, giving morphological and functional information, respectively. On DMSA scans the timing of any preceding urinary tract infection must be considered in order to differentiate diffuse potentially reversible defects in isotope uptake after urinary tract infection from those due to permanent renal scarring.

Adolescent↗

99mTc dimercaptosuccinic acid (DMSA) scan as first investigation of urinary tract infection.

A total of 115 children under 5 years who presented with a first symptomatic urinary tract infection and who had a 99mTc dimercaptosuccinic acid (DMSA) scan were studied to assess its value and compare the findings with those of other imaging techniques. Renal cortical defects were detected in 65 kidneys by DMSA scan, intravenous urogram, and ultrasound scan combined; 62 (95%) being seen on DMSA scan. The finding of reflux on micturating cystourethrography showed a highly significant correlation with renal defects seen on DMSA scanning, a less close but still significant correlation with abnormalities on intravenous urography, but none with ultrasound scan findings. The sensitivity of the DMSA scan in screening for all grades of reflux is estimated as 0.66, which is higher than that previously reported for the intravenous urogram or ultrasound scan. DMSA scans were less likely to miss grade 3 reflux than the other two methods. DMSA scans are more useful than other upper renal tract imaging techniques in detecting renal defects. Consideration should be given to their use as a first investigation in place of routine intravenous urograms. Ultrasound scans alone will overlook potentially serious urinary tract abnormalities.

Child, Preschool↗

Serial 99mTc dimercaptosuccinic acid (DMSA) scans after urinary infections presenting before the age of 5 years.

Forty five children presenting with a first proven urinary tract infection under the age of 5 years were studied by sequential 99mTc dimercaptosuccinic acid (DMSA) scans. Forty nine kidneys in 40 children had definite defects at presentation, and 39 (80%) of these defects were still present when the DMSA scan was repeated. Changes in the appearance of defects were independent of the presence or degree of reflux at presentation and of symptomatic recurrence of infection, though the combination of new infection and grade 3 reflux (reflux reaching the renal calices with distension) was associated with deterioration. No kidney with a relative DMSA uptake of less than 35% showed any improvement in its cortical defects. Only two kidneys that were initially without defects, in a single patient who had bilateral grade 3 reflux and breakthrough infections, developed defects on subsequent scans. The outcome after urinary tract infection is dependent on the effect of the first infection on the kidney. Occasionally children with grade 3 reflux develop damage during subsequent infections. More widespread use of DMSA scans should improve our understanding of the factors that determine the development of renal damage.

Child, Preschool↗

Gastric emptying and intestinal transit of pancreatic enzyme supplements in cystic fibrosis.

OBJECTIVE: To investigate gastric emptying and intestinal transit of pelleted pancreatin in relation to food boluses. METHODS: Dual isotope scintigraphy combined with breath hydrogen sampling was used to track the concurrent gastric emptying and intestinal transit of 111indium labelled microspheres and a 99mtechnetium labelled tin colloid test meal. Twelve pancreatic insufficient cystic fibrosis patients aged 5 to 38 years performed the study. RESULTS: 50% gastric emptying times showed patient to patient variation. The mean discrepancy in 50% gastric emptying times between the two labels was > 67 minutes. Mean small bowel transit time for the food bolus was prolonged at 3.6 minutes. A significant correlation was seen between weight standard deviation score and 50% emptying time for pancreatin (r = +0.73). CONCLUSION: Gastric mixing of food and pancreatin may be limited by rapid emptying of microspheres. Patients with high dosage requirements could benefit from changing the pattern of their pancreatin supplementation.

Adolescent↗

Frozen shoulder: an arthrographic and radionuclear scan assessment.

The diagnostic criteria and nomenclature used to describe the painful stiff shoulder remain confused. Arthrographic features of capsulitis have come to be accepted as characteristic of the frozen shoulder. Increased technetium uptake has also been noted. Both features have been considered to have possible prognostic and therapeutic importance. During a therapeutic study of strictly defined clinical frozen shoulder 35 of 38 patients showed increased technetium diphosphonate uptake in the affected shoulder in comparison with the opposite side. Of 36 patients who had arthrography 15 showed evidence of capsulitis, 11 rupture of the rotator cuff, and five no abnormality. Five tests failed owing to technical difficulty. There was no association between the technetium uptake and the arthrographic features, and neither was useful in predicting the rate or extent of recovery. Frozen shoulder of traumatic onset behaved no differently from that which arose spontaneously. We do not therefore consider that arthrography or technetium diphosphonate scanning performed at presentation contributes to the assessment of the painful stiff shoulder.

Adult↗

Quantitative measurement of biliary excretion and of gall bladder concentration of drugs under physiological conditions in man.

Gall bladder storage of hepatic bile prevents complete recovery of biliary excretion of drugs to be obtained under physiological conditions in man. The aim of this study was to develop and validate a method for simultaneous measurement of gall bladder storage of a cholephilic drug, and of its duodenal excretion and t1/2 in bile. Duodenal perfusion using polyethylene glycol as intestinal recovery marker for measurement of drug duodenal excretion, with an iv bolus of 99mTc HIDA for measurement of drug mass within the gall bladder was used. Gall bladder volume was measured by ultrasonography. T1/2 in bile was measured by relating drug duodenal excretion to that of bile acid used as an endogenous bile marker. The use of bile acid as biliary marker was validated in two subjects receiving simultaneous iv infusion of indocyanine green. Seven healthy subjects were studied using a beta-lattam antibiotic, Cefotetan 1 g iv, as test drug. Median values during the study period (seven hours) were 51.1 mg for Cefotetan duodenal excretion, 45.2 mg for gall bladder mass and 2.8 mg/ml for concentration within the gall bladder. T1/2 of the drug in bile was 100 minutes. This technique enables measurement of mass and concentration of drugs within the gall bladder to be carried out, in addition to measurements of t1/2 of drugs in bile. These measurements may have specific application for assessment of potential efficacy of antibiotics in biliary tract infections, as well as general application for assessment of biliary excretory kinetics of drugs.

Adult↗

How well does stool form reflect colonic transit?

BACKGROUND: Watery stools are equated with rapid and hard stools with slow intestinal transit; however, the relation between stool form and transit through specific regions of the gut is not clear cut. In addition, more information is needed on interindividual variability of these measurements. AIM: To examine the relations between stool form and gastric emptying, small bowel and colonic transit. METHODS: Regional gut transit was assessed scintigraphically and segmental colonic transit was also quantified by radio-opaque markers. On two occasions, 32 healthy volunteers (12 men, 20 women) were studied, women during the follicular and luteal phases of menstruation, men twice within a similar four week period. Diets were standardised and stool form was recorded on a seven point scale. RESULTS: Women had significant harder stools; hard stools were correlated significantly with slow transit and loose stools with fast transit through the colon. CONCLUSIONS: Stool form could not be related to gastric emptying or small bowel transit.

Colon↗

The normal 99mTc-DMSA renal image.

Renal images of 194 normal subjects given 99mTc-dimer captosuccinic acid (DMSA) were reviewed to establish normal values an optimal imaging techniques for this new renal agent. Images were consistently of high quality. Normal renal size (posterior length) averaged 11.5 +/- 1 cm, and renal radioactivity (functioning tubular mass) was equally divided between the left and right kidney. 99mTc-DMSA appears to be an excellent renal parenchymal imaging agent.

Adolescent↗

Role of radionuclide imaging in the diagnosis of postoperative infection.

Postoperative infections are a serious cause of morbidity and mortality and are difficult to diagnose. Signs and symptoms that are generally associated with infection may be masked by, or mistaken for, normal postoperative changes. Anatomic imaging modalities provide high-quality anatomic detail and are the procedures of choice in affected patients because of their availability, ease of performance, accuracy, and value in the selection of treatment options. However, radionuclide studies demonstrate physiologic processes, which often precede anatomic changes, and can help distinguish normal postoperative inflammation from infection. Radionuclide studies are also useful in identifying complicated orthopedic infections, in which the often extensive distortions produced by metallic hardware can confound the interpretation of anatomic images. Of the three agents (gallium-67 citrate, indium-111-labeled leukocytes, technetium-99m-labeled leukocytes) that are currently approved in the United States for imaging of infection, In-111-labeled leukocyte imaging is the procedure of choice for diagnosing postoperative infection. Gallium scintigraphy is best reserved for those situations in which leukocyte imaging is not available or there is concern that the suspected infection may not incite a neutrophil response. In general, the value of radionuclide imaging is maximized when used only in those patients for whom the results of anatomic imaging are negative, nondiagnostic, or at odds with the clinical impression.

Abdominal Abscess↗

Delayed scanning with DMSA: a simple index of relative renal plasma flow.

Relative renal uptake of 99mTc-dimercaptosuccinic acid (DMSA) was compared with the relative effective renal plasma flow (ERPF) to each kidney. In 25 patients with serum creatinine less than or equal to 2.0 mg/dl, there was excellent agreement when the regions of interest were assigned by a computer. In 10 patients with serum creatinine greater than 2.0 mg/dl, agreement was poor. A 24-hour image is sufficient to obtain such data. In patients with renal failure, this technique may give inaccurate results due to high tissue background activity; moreover, since it reflects the current functioning status of the kidney, it should not be used to predict recoverable function in patients with acute or unstable renal disease.

Acute Kidney Injury↗

Internal mammary lymphoscintigraphy in patients with breast cancer. Correlation with computed tomography and impact on radiation therapy planning.

Twenty patients with Stage I or II breast cancer, all of whom had undergone radiation therapy planning, were examined with internal mammary lymphoscintigraphy (IMLS) and computed tomography (CT). Based on the results of IMLS, radiation fields were revised in 12 cases (60%). The mean number of nodes identified by IMLS in each patient was 7.8, which is in agreement with previously published autopsy and scintigraphic data. CT identified 243 possible nodes of normal size, but only 49 of them were within 10 mm of regions shown to be positive on the scintigram. The authors conclude that IMLS is the method of choice for defining parasternal lymphatic drainage and identifying those internal mammary nodes that are normal in both size and function.

Adult↗

The suprahepatic gallbladder. An unusual anatomical variant.

The authors describe a case of ectopic gallbladder found lying posterior to the liver in the subdiaphragmatic space. This condition should be considered whenever the right lobe of the liver is hypoplastic and the gallbladder cannot be visualized on hepatobiliary scans or oral cholecystograms.

Gallbladder↗