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Biomedical subjects

R S Lawson

Publications and source records attributed to R S Lawson.

At least 19 recordsLinked to original sources
PubMed1992

The F-15 diuresis renogram in suspected obstruction of the upper urinary tract.

The results are presented of the first long-term follow-up study of patients with suspected obstruction of the upper urinary tract investigated by a modified form of diuresis renography (F - 15 renography). The incidence of equivocal results from diuresis renography is significantly reduced by the use of the F - 15 renogram. F - 15 renography provides a reliable assessment of the upper urinary tract in patients with suspected obstruction and is recommended in the investigation of equivocal upper urinary tract dilatation.

Adult↗
PubMed1987

Modified method of diuresis renography for the assessment of equivocal pelviureteric junction obstruction.

Thirty-five hydronephrotic kidneys, in which diuresis renography showed either an equivocal (13) or non-obstructive (22) response pattern, were studied by a modified method in which intravenous frusemide was given 15 min before the start of the renogram so as to assess elimination during the period of maximum diuresis. Thirteen kidneys were identified as obstructed, including three in which the standard diuretic renogram appeared to exclude obstruction. These results indicate that the modified method increases the specificity of diuresis renography when used to assess patients with equivocal pelviureteric junction obstruction.

Adolescent↗
PubMed1987

A comparison of technetium-99m-thiodiglycolic acid and iodine-123-hippuran in the evaluation of equivocal upper urinary tract obstruction.

In a comparative trial, 21 patients (mean age 43 (range 19-66) years) with dilated upper urinary tracts underwent diuresis renography with both 123I-hippuran and the experimental agent. 99Tcm-thiodiglycolic acid (TDG). Deconvolution analysis of the derived renograms was also performed and the transit times were calculated. Excellent agreement was found between results with the two radiopharmaceuticals. There was complete agreement in interpretation of the response to diuresis with both agents and 84% agreement in the transit time estimations. Good images were produced with both agents and 99Tcm-TDG is considered to be a useful alternative to 123I-hippuran.

Adult↗
PubMed1987

The importance of using anterior and posterior views in the calculation of differential renal function using 99Tcm-DMSA.

Radionuclide techniques for determining relative renal function are well established. One simple method uses the count rate from static images obtained using 99Tcm-dimercaptosuccinic acid (DMSA). We have reviewed 277 DMSA scans and shown that it is important to obtain the geometric mean of counts from the anterior and posterior views in order to correct for the different amounts of attenuation for each kidney. If counts were obtained from the posterior view only, erroneous results would be obtained in 8% of children under 13 years, in 28% of patients aged between 13 and 20 years and in 32% of patients over 20 years of age.

Adolescent↗
PubMed1979

Idiopathic hydronephrosis--the diuresis renogram: a new non-invasive method of assessing equivocal pelvioureteral junction obstruction.

A new method to evaluate patients with equivocal obstruction of the pelvioureteral junction is described. It involves the performance of a standard 131iodine-hippuran renogram followed by a second renogram 3 minutes after an intravenous injection of the diuretic, frusemide. When the 2 results are inspected together it is found that the patients can be separated into 4 groups: 1) normal, 2) obstructed, 3) atonic and 4) partially obstructed. The results in 23 children and 27 adults with suspected obstruction of the pelvioureteral junction are presented. Obstruction was confirmed in 18 patients and excluded in 32. The correlation between the renogram results and clinical, radiological and operative findings is discussed. The technique is simple, accurate and non-invasive, and it is recommended after excretory urography before proceeding to more invasive tests.

Adult↗
PubMed1979

Diuresis renography and the results of pyeloplasty for idiopathic hydronephrosis.

Eighty-six kidneys in 82 patients have been assessed by diuresis renography after pyeloplasty. A non-obstructed diuresis renogram was found in 64% of kidneys. Ninety per cent of patients were clinically improved by surgery and 51% of cases studied had improved urographic features. Thirty kidneys (29 patients) were assessed both before and after pyeloplasty. An improvement in the diuresis renogram was found in 89% of cases postoperatively. Standard renography demonstrated improved drainage in only 33% of kidneys. These findings are discussed in relation to the value of diuresis renography after pyeloplasty.

Adolescent↗
PubMed1979

Diuresis renography and morphology in upper urinary tract obstruction.

The results of a combined study of 25 patients with idiopathic hydronephrosis are presented. Diuresis renography was performed pre-operatively and surgically removed specimens of the renal pelvis and ureter were examined by light and electron microscopy. There was good correlation between the results of these 2 methods of assessment which have defined 2 broad categories of patients with renal pelvic dilatation. These findings are discussed with particular reference to the clinical value of diuresis renography.

Adolescent↗
PubMed1978

Diuresis renography in equivocal urinary tract obstruction.

A trial of the value of diuresis renography in equivocal upper urinary tract obstruction is presented. Fifty-two patients were examined by standard renography and renography under a diuretic provocation. The results indicate that the technique is of considerable value in making the vital distinction between dilatation on the excretion urogram due to atonicity and that caused by a genuine obstruction. A quantitative index of the response to diuresis reflecting the degree of impedance to flow is described--the Diuresis Excretion Index. Diuresis renography is recommended in the evaluation of the patient with equivocal urinary tract obstruction.

Diuresis↗
PubMed1977

123-Iodine: a new isotope for functional renal scanning.

The results are presented of functional renal scanning in 11 urological patients using 123-iodine labelled Hippuran--a new radiopharmaceutical. The 123-iodine isotope possesses distinct advantages over existing isotopes, permitting high resolution imaging whilst delivering a low integrated radiation dose. It is hoped that the expense of this cyclotron-produced isotope will not mitigate against full evaluation of its promising potential.

Adult↗
PubMed1977

Dynamic scintigraphy in clinical urology.

The technique of isotope renal scintigraphy using Technetium-99m labelled agents and a gamma camera system on-line to a digital computer is described. Its value in diagnosing renal space-occupying disease and renovascular abnormalities is emphasised. A method of measuring individual renal haemodynamics and the possible potential of such techniques are discussed. Radio-isotope studies are rapid, simple, non-invasive and non-toxic. They give information complementary to that from urography.

Adult↗