Correction of the slope-intercept method for the measurement of glomerular filtration rate.

Objective: Glomerular filtration rate (GFR) is frequently assessed using the slope-intercept method by fitting a single exponential to plasma samples obtained 2-5 h after injection. The body surface area (BSA)-corrected one-pool clearance (CO,BSA) overestimates true GFR (CT,BSA) because it fails to sample the full plasma curve, and values of CT,BSA are usually estimated from CO,BSA using the Brøchner-Mortensen (BM) equation. An improved equation, CT,BSA=CO,BSA/(1+fBSA×CO,BSA), with fBSA a fixed constant, was proposed by Fleming, but subsequently Jødal and Brøchner-Mortensen (JBM) reported that fBSA varies with BSA.

UK audit of glomerular filtration rate measurement in 2001.

Objective: To investigate the consistency of glomerular filtration rate (GFR) calculation from plasma sampling in the UK.

Methods: Ten patients' data sets from plasma sampling measurements of GFR were distributed throughout the UK. The data included count rates from four samples taken between 2 and 4 h after injection, a diluted sample of injected dose for standardisation, the patient's height, weight, age and sex.

International Scientific Committee of Radionuclides in Nephrourology (ISCORN) consensus on renal transit time measurements.

This report is the conclusion of the international consensus committee on renal transit time (subcommittee of the International Scientific Committee of Radionuclides in Nephrourology) and provides recommendations on measurement, normal values, and analysis of clinical utility. Transit time is the time that a tracer remains within the kidney or within a part of the kidney (eg, parenchymal transit time). It can be obtained from a dynamic renogram and a vascular input acquired in standardized conditions by a deconvolution process.

UK audit of left ventricular ejection fraction estimation from equilibrium ECG gated blood pool images.

Purpose: To examine the variability of results obtained from computer analysis of left ventricular gated blood pool (LVGBP) images by nuclear medicine centres in the UK.

Methods: Twelve data sets of LVGBP images were distributed via commercial software suppliers to nuclear medicine centres in the UK. Two of the data sets were duplicates and three were acquired from the same patient with different total counts in the images.

UK audit of relative lung function measurement from planar radionuclide imaging.

Background: Quantitative measurements of regional lung ventilation and perfusion are useful adjuncts to image interpretation.

Aim: This study investigated the accuracy and precision of the software used to carry out such measurements in the UK.

Methods: Ten examples of perfusion distribution, representing the range of patterns expected in practice, were simulated on computer using a segmental model of the lung and real three-dimensional lung shapes obtained from magnetic resonance images.

Guidelines for the measurement of glomerular filtration rate using plasma sampling.

These guidelines have been adopted by the British Nuclear Medicine Society.

UK audit of single photon emission computed tomography reconstruction software using software generated phantoms.

The purpose of this study was to undertake an audit of the quantitative characteristics of single photon emission computed tomography software using projection data from an analytically generated software phantom and a measured line source. The phantom consisted of three structures. A uniformly filled cylinder, a series of cylindrical rods of various diameters in a background activity with a rod to background ratio of 2:1 and lastly, a set of three concentric rings of activity in the ratio 1:0:1.

UK audit and analysis of quantitative parameters obtained from gamma camera renography.

The purpose of this study was to perform an audit of quantitative values obtained from gamma camera renography in the UK. Ten patient image sequences representing normal and pathological renal function were obtained from archived studies and distributed to hospitals in the UK. Hospitals were asked to measure five parameters: relative function, renogram time-to-peak (left and right), and whole kidney mean transit time (left and right).

A survey of guidelines in 27 EANM associated societies by the EANM Task Group on Quality Assurance and Standardisation. European Association of Nuclear Medicine.

The main aim of the EANM Task Group on Quality Assurance and Standardisation is to develop harmonised clinical procedures that are accepted within Europe. In order to achieve an evidence-based analysis of guidelines in the 27 EANM member societies, a survey was conducted. A questionnaire in mid 1999 investigated three major questions: (1) current status of national guidelines in EANM member societies, (2) specification of the cover and level of these national guidelines, and (3) future desires for national, EANM and SNM guidelines.

Estimating plasma volume from red cell volume.

Following the withdrawal of the only licensed supply of 125I-HSA in 1997, most UK centres now simply estimate plasma volume from a knowledge of the red cell volume and venous haematocrit. We compared measured and estimated plasma volume in 107 consecutive patients who had had red cell and plasma volume measured independently in the conventional way. In only 40% of cases was the estimated value accurate to within +/- 5%, and discrepancies of more than +/- 10% were seen in 35%.

Appropriate corrections to glomerular filtration rate and volume of distribution based on the bolus injection and single-compartment technique.

The bolus injection, single-compartment technique for measuring GFR overestimates the true value. Nevertheless, assuming that for a given indicator the area under the first exponential of the plasma clearance curve is constant from subject to subject, the observed (uncorrected) value can be corrected by multiplication with a 'sliding' factor, the value of which is a nonlinear function of GFR. Several second-order polynomials, based on pre-determined relationships between simultaneously determined two-compartment and one-compartment GFR, have been described for correcting GFR (GFR correction).

Consensus report on quality control of quantitative measurements of renal function obtained from the renogram: International Consensus Committee from the Scientific Committee of Radionuclides in Nephrourology.

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.

UK audit of relative renal function measurement using DMSA scintigraphy.

A variety of software is used to determine quantitative parameters from radionuclide imaging procedures. Knowledge of the variability of parameter values found in different hospitals is an important aspect of clinical audit of these techniques. This study investigated the variation in relative renal function measurement from static DMSA scintigraphy in the UK.

Quality assurance in renography: a review.

Despite the fact that renography is practised by most nuclear medicine departments, some doubt remains about its clinical utility in certain settings. Unfortunately, lack of standardization has made it difficult to judge whether some reports of poor diagnostic accuracy are due to a fundamental limitation of the test, or simply to sub-optimal implementation. Some important work may therefore have been overlooked.

Measurement of the extravascular concentration of renal agents following intravenous bolus injection.

The extravascular concentration (Ce) of some renal agents, in relation to the simultaneous plasma concentration (Ci), was calculated as a function of time after intravenous injection. Four agents were studied: 51Cr-ethylenediamine tetraacetate (EDTA) (n = 11), 125I-hippuran (n = 11), 99Tcm-dimercaptosuccinic acid (DMSA) (n = 11) and 99Tcm-mercaptoacetyl triglycine MAG3 (n = 20). Plasma clearance curves were constructed from data acquired from multiple blood sampling and fitted with two exponentials.

Quality assurance of medical software.

Quality assurance is a topical issue within the software industry, and various methodological solutions aimed at improving software quality have been proposed. Medical software is generally deemed safety-critical and, as such, should be subject to control procedures exceeding those applicable to general-purpose software. The user/purchaser of medical equipment has an important part to play in the drive for higher-quality medical software, and ways in which the user can influence commercial suppliers are outlined.

User requirements for information systems in nuclear medicine.

In the field of COST cooperation (COST = European Cooperation in the Field of Scientific and Technical Research) a project B2 for Quality Assurance in Nuclear Medicine Software has been established. In a memorandum of understanding setting up this project, user requirements were to be defined for the hardware and software used for data acquisition, processing and presentation. A subgroup of the management committee of COST B2 were interested in the Advanced Informatics in Medicine, AIM, task T-734 'Quality Assurance of Medical Software', and the AIM Project 'A 1034', coordinated by Dr K.