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Biomedical subjects

I Gordon

Publications and source records attributed to I Gordon.

At least 163 records · Page 9Linked to original sources
PubMed1991

Estimation of technetium-99m-MAG3 renal clearance in children: two gamma camera techniques compared with multiple plasma samples.

Dynamic renal scintigraphy using technetium-99m mercaptoacetylglycylglycylglycine (MAG3) has been described in adults, and clearance values have been established using multiple plasma samples. This study of renal clearance has compared two fundamentally different gamma camera techniques (both of which require a single blood sample) with the multiple blood sampling technique in children (n = 30). Results show that a 40-min dynamic 99mTc-MAG3 renal scintigram coupled with a single plasma sample will allow analysis of the data so that clearance values, which are similar to those from multiple plasma samples, may be calculated. The curve generated from the cardiac region of interest (ROI) provided clearances values that had a high correlation coefficient (0.939-0.951) compared to the multiple-plasma sample technique immaterial of the timing of the blood sample. The renal uptake method of clearance had a lower correlation coefficient (0.89-0.92), which varied with the timing of the blood sample compared to the multiple-plasma sampling technique. This study has demonstrated that an extended gamma camera acquisition coupled with a single-plasma sample may be used for quantitative renal function studies using 99mTc-MAG3.

Adolescent↗
PubMed1991

Antenatal diagnosis of pelvic hydronephrosis: assessment of renal function and drainage as a guide to management.

The optimal management of children with antenatally diagnosed unilateral hydronephrotic kidneys is unclear. We have monitored renal function and drainage using 99mTc-DTPA renography in 77 children with such kidneys presenting at 1-14 mo of age with the aims of throwing light on the natural history of the condition and evaluating the response of the kidney to pyeloplasty. Since management was independent of the drainage criteria on renography, the opportunity also was presented to evaluate the efficacy of diuretic renography for diagnosing obstruction in these children. Follow-up ranged between 1 and 6 yr, during which renography was performed between 2 and 6 times in each patient. Thirty-nine patients were treated conservatively, while 30 patients underwent pyeloplasty at varying times after presentation. No overall significant change in function was observed either in the nonoperated children or as a result of surgery. This also applied to sub-groups of children with poor drainage. Function improved significantly, however, in a sub-group of nonoperated children who presented with impaired function in the hydronephrotic kidney. Surgery, although having no overall effect on function, significantly improved drainage. As a means of identifying obstruction, 99mTc-DTPA diuretic renography was unreliable, erroneously indicating obstruction in 24 nonoperated children in whom function of the hydronephrotic kidney never became abnormal and who could not, therefore, have been considered to have obstruction. This retrospective study underlines the importance of performing a randomized prospective study on the value of pyeloplasty in this group of children.

Diuresis↗
PubMed1991

Comparison of changes in transit time ultrasound, esophageal Doppler, and thermodilution cardiac output after changes in preload, afterload, and contractility in pigs.

The purpose of this study was to compare how well changes in cardiac output (CO) measured by esophageal Doppler (Doppler) and thermodilution (TD) followed changes in CO measured by transit time ultrasound (TTU). Simultaneous Doppler, TD, and TTU measurements of CO were made before and after changes in preload, afterload, or contractility in seven piglets. Mean changes in each CO method for each type of change in CO were compared by analysis of variance. Changes in TTU CO, TD CO, and Doppler CO were compared by correlation, linear regression, and bias and precision statistics. Of 86 TTU changes in CO greater than 10%, Doppler changed the same direction as TTU 59 times, changed in an opposite direction 6 times, and changes less than 10% 21 times. Thermodilution changed in the same direction as TTU 72 times, in the opposite direction 4 times, and changed less than 10% 10 times. Changes (% delta) in TTU and TD measurements of CO were not significantly different in any group. Changes in Doppler CO and TTU CO were different for two afterload and contractility groups. Percent changes in Doppler CO had a correlation coefficient (r) = 0.74, m = 0.72, and bias (mean % delta Doppler CO - mean % delta TTU CO) = 6.3 +/- 29.7 with % delta TTU CO. Percent changes in TD CO had an r = 0.90, m = 0.92, and bias = 5.7 +/- 19.1 with % delta TTU CO. Cardiac output measured by Doppler underestimated changes in CO due to changes in preload and contractility and exaggerated changes in CO due to changes in afterload.

Analysis of Variance↗
PubMed1990

Total respiratory compliance in infants and young children with congenital heart disease.

The multiple occlusion technique was used to measure total respiratory system compliance (Crs) in 62 infants and young children with congenital heart disease (age range, 2 days to 2 years). Measurements were found to be reproducible in nine infants in whom repeat measurements were possible (maximum deviation between measurements less than 10%). The incidence of failure to obtain accurate results was no greater than when studying infants without cardiopulmonary disease. However, in the presence of severe growth retardation or alinearity of volume-pressure data, results may be difficult to interpret in individuals. Results of Crs were related to non-invasive assessments of cardiac disease severity using chest radiography and echocardiography. After the effects of growth had been taken into account, a significant negative relationship was found between Crs and the right pulmonary artery to aortic ratio, which reflects pulmonary vascular engorgement (P = 0.003, R2 = -0.40). However, no significant relationship was found between Crs and chest X-ray score (P = 0.27).

Aorta↗
PubMed1990

Metastatic neuroblastoma: new abnormalities on bone scintigraphy may not indicate tumour recurrence.

Neuroblastoma is a potentially curable childhood malignancy with survival rates of 20% reported even in advanced disease. Technetium-labelled methylene diphosphonate (Tc99m-MDP) scanning is well established as a method of assessing bone disease. We report four patients, with advanced neuroblastoma in complete or partial remission, in whom new abnormalities on bone scintigraphy were due to benign lesions. Correct management depends on the precise diagnosis of such lesions.

Bone Diseases↗
PubMed1990

A radiopharmaceuticals schedule for imaging in paediatrics. Paediatric Task Group European Association Nuclear Medicine.

There is no standard schedule for the amounts of radiopharmaceutical administered to children at present. Various alternative methods are currently in practice, all with some support from the literature. Optimization of the amount of radiopharmaceutical to be administered is discussed in relation to the radiation burden of such an examination. The Paediatric Task Group of the European Association of Nuclear Medicine has investigated the current situation and now suggests a method for standardization of administered amounts of radiopharmaceutical in paediatrics. The fraction of the adult amount of radiopharmaceutical to be administered should be calculated from the child's body weight according to the accompanying table. In small infants, the minimum amount of a radiopharmaceutical is discussed and suggested amounts to be administered are presented.

Body Weight↗
PubMed1990

Indirect radionuclide cystography: a sensitive technique for the detection of vesico-ureteral reflux.

The detection or exclusion of vesico-ureteral reflux (VUR) has classically been by micturating cystourethrography (MCUG). Radionuclide cystography will detect VUR but fails to provide the same detailed anatomical informations as MCUG. This study allowed a comparison of indirect radionuclide cystography (IRC) and MCUG in 65 children. Renal reflux was detected by IRC in 32% of renal units, while VUR was seen in 36% by MCUG. When a comparison was made with MCUG, IRC had a sensitivity of 74.1% and a specificity of 90.5%. The markedly reduced radiation dose, avoidance of a bladder catheter plus the ability to monitor the urinary tract constantly during the entire procedure should ensure that IRC is the examination of choice in follow-up studies for VUR in all toilet-trained children.

Adolescent↗
PubMed1990

Quantitation of vesico-ureteral reflux by radionuclide cystography and urodynamics.

A method is described for the quantitation of vesico-ureteral reflux by synchronous combined direct radionuclide cystography and urodynamics. Intravesical pressures and volumes are co-ordinated with volumes of reflux. Peak reflux volumes in 11 children diagnosed as having severe (grades 3-4) reflux on conventional contrast cystography ranged from 1 to 50 ml/kidney. A number of different patterns of reflux were observed. Reflux may occur progressively throughout low pressure filling or incrementally with unstable bladder contractions. Reflux during voiding may be maximal as detrusor pressure falls. The method requires wider application to explore the potential for a functional classification of the reflux problem.

Child↗
PubMed1990

Indirect radionuclide cystography demonstrates reflux under physiological conditions.

Indirect radionuclide cystography (IRC) is a useful technique for the detection and quantification of vesico-ureteric reflux (VUR). Its principal advantage over micturating contrast cysto-urethrography (MCU) is its ability to demonstrate VUR under physiological conditions. Three children (age range 6-9 years) reported here illustrate some physiological features of micturition readily seen only on IRC. The most important of these was uretero-ureteric reflux which, because of bladder activity, is not usually identifiable on IRC or MCU but is probably more common than previously thought and misinterpreted as VUR.

Child↗
PubMed1990

Infantile lobar emphysema in association with congenital heart disease.

Three cases of congenital heart disease (CHD) are presented; all infants developed the unusual complication of lobar emphysema (LE). In all cases delay in reaching the correct diagnosis resulted in two of the infants undergoing a second operation to resect the emphysematous lobe. The chest radiograph in all cases was dominated by the heart disease and the radiological signs of LE were initially missed. The radionuclide ventilation/perfusion lung scan was used in two of these infants to provide conclusive proof and to emphasise the clinical significance of the condition. Lobar emphysema in association with CHD should be recognised early and lobectomy performed at the same time as surgical correction of the heart defect.

Female↗
PubMed1990

Clinicopathologic review of twelve children with nephropathy, Wilms tumor, and genital abnormalities (Drash syndrome).

The clinicopathologic and radiologic features of 12 children with complete and incomplete forms of Drash syndrome are reported. Their common denominator was a nephropathy. Four had the full triad, consisting of nephropathy, Wilms tumor, and genital abnormalities; five had nephropathy and genital abnormalities, and three had nephropathy and Wilms tumor. Of the 11 children who had proteinuria, eight had the nephrotic syndrome. Of the 10 whose condition progressed to end-stage renal failure, seven were less than 3 years of age. The histologic features of Wilms tumor were favorable in all seven children, and the tumor was bilateral in three. Of the nine patients who had genital abnormalities, eight had 46,XY karyotype and either ambiguous genitalia (six patients) or normal female phenotype (two). One other patient had a normal 46,XX female karyotype and phenotype but had both müllerian and wolffian structures and a streak ovary. Nine patients had a distinct pelvicaliceal abnormality not previously reported as a feature of this syndrome. Other congenital abnormalities were aniridia, mental retardation, deafness, nystagmus, and cleft palate. This syndrome must be considered in any infant with unexplained nephropathy, particularly in young phenotypic female infants and in those children with ambiguous genitalia or Wilms tumor with an early presentation.

Child↗
PubMed1990

The postnatal management of hydronephrosis diagnosed by prenatal ultrasound.

A total of 112 patients (142 kidneys) presented with hydronephrosis consistent with ureteropelvic junction obstruction that had been diagnosed by prenatal ultrasound. The kidneys were classified as having poor, moderate or good function based on isotope imaging at 3 months after birth. Of 9 kidneys that showed poor function 3 recovered sufficient function on pigtail drainage to justify preservation and these patients underwent pyeloplasty. Of 27 kidneys with moderate function 23 also underwent pyeloplasty and 14 of these demonstrated improvement in function postoperatively. Of the 100 kidneys in the good function group that were followed conservatively 23 underwent pyeloplasty during followup primarily because of an observed decrease in function. We propose that there is no indication for immediate pyeloplasty in infants with prenatally diagnosed hydronephrosis who demonstrate good function postnatally.

Fetal Diseases↗
PubMed1990

Long term follow up after inhalation of foreign bodies.

The long term results of treatment of inhalation of foreign bodies in a district children's hospital and in a tertiary referral centre were reviewed by clinical assessment, chest radiography, and standard four view 81mKr ventilation/99mTc macroaggregated albumin perfusion imaging (V/Q lung scan). The overall incidence in the population served by the district hospital was roughly one in 14,000/year. Of the 12 children reviewed there, three had abnormal chest radiographs and four had abnormal V/Q scans as a result of inhalation of the foreign bodies. Of 21 children treated and reviewed at the referral centre, eight had abnormal chest radiographs, and 14 had abnormal V/Q lung scans. Three factors were assessed for prognostic importance: site of impaction, initial radiographic appearance, and time before removal. A child who had inhaled a foreign body into the left lung and who had collapse/consolidation on the initial chest radiograph was at greatest risk of long term complications. These children merit close follow up.

Child, Preschool↗
PubMed1990

Pulmonary sequelae in survivors of congenital diaphragmatic hernia.

Nineteen survivors of congenital diaphragmatic hernia repair were compared with age and sex matched control children six to 11 years after repair. All subjects were examined clinically and underwent lung function testing. The patients also had individual lung volumes assessed radiographically and had radionuclide (krypton-81 m, technetium-99 m macroaggregates) ventilation-perfusion (V/Q) lung scans. Four patients had pectus excavatum and two had mild scoliosis. Spirometric measurements were lower in the patients than in the control subjects but only the differences in peak expiratory flow and flow at 50% of expired vital capacity were significant. The radiographic left lung volumes in patients surviving left diaphragmatic repair were larger than expected at 49.3% (SD 2%), suggesting alveolar overdistension. V/Q scans showed a mismatch in the ipsilateral lung, mean Q (40% (7%] being significantly lower than mean V (47% (6%)). In seven patients who had required ventilation for four days or more perfusion to the ipsilateral lung was significantly lower (34% (6%)) than values for the 12 patients ventilated for less than four days (43% (6%)). Survivors of right diaphragmatic repair had a better outcome in terms of relative radiographic lung volumes and V/Q distribution. More severely affected children are now surviving repair of congenital diaphragmatic herniation, with residual pulmonary abnormalities that could produce functional impairment in adult life.

Child↗
PubMed1990

Comparison of 99Tcm dimercaptosuccinic acid scans and intravenous urography in children.

A retrospective comparison of 99Tcm dimercaptosuccinic acid (DMSA) scans and intravenous urograms (IVUs) was performed on a large, unselected paediatric population to assess critically the relative merits of these two techniques. A total of 205 children were studied, providing 388 kidneys for comparison. The studies agreed in 81%, both being normal in 39%, and both abnormal in 42%. In 28 kidneys (7%), the IVU was abnormal when the 99Tcm DMSA was normal. There was a collecting system abnormality in 27 kidneys, but 10 kidneys also showed a parenchymal abnormality. In all these the parenchymal abnormality was global thinning on the IVU, and the contralateral kidney was small. In 40 kidneys (10%) the 99Tcm DMSA was abnormal when the IVU was normal: the abnormalities demonstrated were predominantly focal defects. After excluding IVUs of poor diagnostic quality, only 14 kidneys (3.6%) showed this disparity. The important clinical subgroups are infection, with or without reflux (27 kidneys), hypertension (4) and neonates with poor renal function (2). The one false positive 99Tcm DMSA was a result of an anatomical variant. Global thinning in a "normal" kidney on a 99Tcm DMSA scan may be overlooked when the contralateral kidney is poorly functioning and small.

Adolescent↗