THUR 199 MS DMT monitoring according to abn guidelines & product specification

Aim

Retrospective audit monitoring Multiple Sclerosis (MS) patients on Disease Modifying Therapies (DMT’s) according to Association of British Neurologists (ABN) guidelines (2015) and product specifications. This requires blood tests prior and during treatment and reviews by MS professionals.

Methods

MS nurse database identified patients, records were reviewed and data extracted including bloods, JC virus (JCV) testing, imaging, specialist tests and counselling. Analysis was presented to the MS team. Protocols and referral pathways were designed, and new patients were re-audited.

Results

The first cycle comprised of 280 patients, representing 325 individual DMT regimens. Prior to commencing treatments 90.7% blood tests, 58% imaging, and 60% JCV testing was completed on average. At 12 months, this decreased to 88.7% bloods, 30% imaging, and 25% JCV testing. Electronic records revealed that counselling documentation was sometimes incomplete. The second cycle analysed 55 patients showing improvement in Progressive multifocal leukoencephalopathy counselling and annual imaging.

Conclusion

Monitoring of bloods is done at a high standard, imaging and JCV testing less frequently meet monitoring guidelines. Factors influencing this include rural locations, variation in practice, and changing guidelines. Further work will include yearly follow-up, documentation of stopping criteria and regular review of monitoring guidelines. Patient involvement should be considered.

CA549 and TPS Patterns in the Diagnosis and Staging of Patients with Breast Carcinoma

This study compares the clinical value of the breast cancer tumour markers CA549 and TPS, and their tandem use when one or both markers indicate abnormality. For 144 patients presenting with active disease, 33 were classified as Stage I, 37 as Stage II, 40 as Stage III and 34 as Stage TV. For these patients the sensitivity of CA549 using a cut-off of 10 U/ml was 27%, 32%, 42% and 79%, respectively. The sensitivity of TPS for each stage using a cut-off of 100 U/l was 12%, 22%, 28% and 73%, respectively. At these cut-off levels, 36%, 46%, 63% and 91% of patients, respectively, have either CA549 or TPS or both markers raised. For 161 patients with diagnosed benign breast disease, the specificity of marker levels was 96% for CA549, 88% for TPS and 84% for tandem use. CA549 is shown to be superior to TPS and this was confirmed by Receiver Operating Characteristic (ROC) analysis using variable threshold levels, with the areas under the curves for all stages combined being 0.74 ± 0.03 (1SD) and 0.66 ± 0.03, respectively. The corresponding area under the curve for tandem use (0.75 ± 0.03) is marginally greater than for either individual marker, although the difference with respect to CA549 is statistically insignificant.

Psychiatric features of new variant Creutzfeldt-Jakob disease

Aims and method

New variant Creutzfeldt–Jakob disease is a novel prion disease of humans that may be causally linked to bovine spongiform encephalopathy. Psychiatric symptoms occur in the early stages of the illness and may be difficult to distinguish from the symptoms of more common psychiatric disorders. Cases of new variant Creutzfeldt–Jakob disease are identified through the national surveillance system. Information on psychiatric features has been obtained by review of case notes and, in the majority of cases, by interview of relatives by a member of the surveillance staff.

Results

Thirty-five cases of new variant Creutzfeldt–Jakob disease have been identified in the UK and detailed information on the clinical features and investigations is currently available in 33 of these cases. All but one of the cases exhibited prominent early psychiatric symptomatology, but the diagnosis of an underlying neurological disease was not possible in the majority of cases until the development of neurological symptoms and signs. Early indications of an underlying neurological disorder included cognitive impairment, persistent sensory symptoms or limb pain and, in a minority, gait imbalance, dysarthria or visual symptoms. Limited evidence suggests that investigations such as electroencephalogram or brain imaging are unlikely to provde useful diagnostic information during the ‘psychiatric’ phase of the illness.

Clinical implications

The early recognition of an underlying neurological disorder may be impossible in the early psychiatric phase of new variant Creutzfeldt–Jakob disease, but the suspicion of this diagnosis may be raised by the occurrence of associated neurological symptoms. The development of early diagnostic markers is an important objective.

[111Indium-DTPA-D-phe] octreotide scintigraphy in the diagnostic assessment of palpable breast lumps

It has been suggested that [111Indium-DTPA-D-Phe] octreotide scintigraphy may be useful in the staging of breast cancer. We evaluated its role in the diagnostic assessment of 40 female patients with palpable breast lumps. All were clinically assessed and imaged by ultrasound or mammography. Thirty patients had adequate FNA cytology performed. Histological examination following core or excision biopsy showed 31 lumps to be benign and 9 to be malignant. All patients with invasive cancer proceeded to wide local excision or mastectomy with an axillary clearance. The mean diameter of malignant lesions was 2.4 cm (SEM 0.3 cm). The sensitivity (22%), specificity (81%) and positive predictive value (25%) of octreotide scintigraphy in the detection of breast cancer was inferior to that of clinical assessment (56%, 90% and 71%), radiological imaging(77%, 96% and 100%) and FNA cytology (88%, 95% and 88%). No axillary uptake of isotope was seen in 4 patients with nodal metastases. Four scans showed uptake of isotope at one or more sites remote from the clinically or radiologically significant lesion. [111Indium-DTPA-D-Phe] octreotide scintigraphy provided no additional diagnostic information to that given by triple assessment and does not appear to have a role in the evaluation of breast lumps.

Geographical distribution of variant Creutzfeldt-Jakob disease in Great Britain, 1994-2000

BACKGROUND

Geographical variation in the distribution of variant Creutzfeldt-Jakob disease (vCJD) might indicate the transmission route of the infectious agent to man. We investigated whether regional incidences of vCJD were correlated with regional dietary data.

METHODS

The National CJD Surveillance Unit prospectively identified 84 people with vCJD up to Nov 10, 2000, in Great Britain. Their lifetime residential histories were obtained by interviews with a close relative. Cumulative incidences of vCJD by standard region were calculated. Grid references for places of residence in 1991 were identified and evidence of geographical clusters were sought. Data on diet in the 1980s were analysed for regional correlations with vCJD incidence. The socioeconomic status of the places of residence of people with vCJD was compared with that of the general population.

FINDINGS

vCJD incidence was higher in the north of Great Britain than the south. The rate ratio (north vs south) was 1.94 (95% CI 1.27-2.98). The mean Carstairs' deprivation score for areas of residence of people with vCJD was -0.09 (-0.73 to 0.55), which is close to the national average of zero. Regional rates of vCJD were correlated with consumption of other meat or meat products as classified and recorded by the Household Food Consumption and Expenditure Survey (r=0.72), but not with data from the Dietary and Nutritional Survey of British Adults. Five people with vCJD in Leicestershire formed a cluster (p=0.004).

INTERPRETATION

Regional differences in vCJD incidence are unlikely to be due to ascertainment bias. We had difficulty determining whether regional variations in diet might cause these differences, since the results of dietary analyses were inconsistent.

Diagnosis of new variant Creutzfeldt-Jakob disease

As of December 31, 1998, 35 deaths had been attributed to new variant Creutzfeldt-Jakob disease (nvCJD) in the United Kingdom, of which 33 cases had been neuropathologically confirmed and 2 classified as probable nvCJD. Fifteen cases were male and 20 female. The median illness duration was 14 months (range, 8-38 months) and the median age at death was 29 years (range, 18-53 years). The dinical features were consistent with previous descriptions. In nearly all cases, there were early psychiatric symptoms after a median period of 6 months ataxia developed, followed by involuntary movements and cognitive impairment. Electroencephalograms did not show the "typical" appearances found in sporadic CJD, about half the cases tested had a positive 14-3-3 immunoassay, and over 70% of cases had bilateral pulvinar high signal on magnetic resonance brain scanning. Prion protein gene analysis showed that all cases were homozygous for methionine at codon 129. Diagnostic criteria for nvCJD have been formulated, which have a high sensitivity and specificity.

The pulvinar sign on magnetic resonance imaging in variant Creutzfeldt-Jakob disease

BACKGROUND

There is a need for an accurate non-invasive diagnostic test for variant Creutzfeldt-Jakob disease (vCJD). We investigated the sensitivity and specificity of bilateral pulvinar high signal on magnetic resonance imaging (MRI) for the diagnosis of vCJD.

METHODS

MRI from patients with vCJD and controls (patients with suspected CJD) were analysed. Scans were reviewed on two separate occasions by two neuroradiologists and scored for the distribution of changes, and likely final diagnosis. Scans from vCJD cases were reassessed to reach a consensus on all abnormalities.

FINDINGS

We analysed 36 patients and 57 controls. vCJD patients were correctly identified based on bilateral pulvinar high signal in 29 of 36 and 32 of 36 cases on the first assessment by the two radiologists, and 32 of 36 and 31 of 36 on their second assessment. Bilateral increased pulvinar signal was identified in one of 57 and one of 57 controls on the first assessment and two of 57 and three of 57 controls on the second assessment. These reported changes in controls were graded as minimal/equivocal in six of seven patients and moderate in one (<0.5% of all control assessments). 80% of the assessments in vCJD cases were graded as moderate or substantial. On consensus review, 28 of 36 cases and none of 57 controls had prominent bilateral pulvinar signal-sensitivity 78% (95% CI 60-90%) and specificity 100% (95% CI 94-100%). Other common MRI features of vCJD were medial thalamic and periaqueductal grey matter high signal, and the notable absence of cerebral atrophy. Pulvinar high signal correlated with histological gliosis.

INTERPRETATION

In the appropriate clinical context the MRI identification of bilaterally increased pulvinar signal is a useful non-invasive test for the diagnosis of vCJD.

Cerebral perfusion and psychometric testing after exposure to high altitude in the mountains

Exposure to hypobaric hypoxia is known to cause reductions in mental performance and decision-making and it has been reported that these effects are not fully reversed following descent from altitude. Eight climbers had cerebral perfusion scans performed and undertook a battery of psychometric tests prior to, and upon return from, an expedition to climb the eleventh highest mountain in the world, Gasherbrum 1. No decrements were found in either their performance on the psychometric tests nor to their cerebral perfusion following the expedition. Two subjects had significant cerebral perfusion abnormalities prior to the expedition, which had improved immediately following their return from the expedition. Repeat scans four months later showed the lesion of one of the subjects had returned and there were indications that the lesion in the other subject was beginning to return. These findings are in contrast to previous studies which have suggested that altitude exposure leads to permanent reductions in brain function, this could be because in those studies factors other than hypobaric hypoxia per se lead to the reductions in brain function.

An assessment of two methods for generating automatic regions of interest

Two fully automatic methods for generating regions of interest (ROIs) for nuclear medicine images are described and assessed. One of these, involving registration of a previously defined ROI onto a new image, uses spatial information and is appropriate for two- and three-dimensional images which may be static or dynamic. The other method is based on artificial neural networks and uses temporal information. It is appropriate for dynamic images only. The registration method has been tested using 10 pairs of stress and redistribution images obtained from cardiac perfusion SPET. Regions of interest of the left ventricular muscle, defined on the stress images, were registered onto the redistribution images, where they were compared with reproducibility of manually drawn ROIs. Both methods were tested on 17 99Tcm-MAG3 kidney dynamic studies, where the original ROIs corresponding to both kidneys and the bladder were defined using the COST B2 hybrid phantom. Our results indicate that neither method is as reliable as having ROIs redrawn by the operator, although there are indications that an artificial neural network which combines the use of the spatial and temporal information could prove useful for dynamic studies.

Use of significance image to determine patterns of cortical blood flow abnormality in pathological and at-risk groups

The purpose of this work was to determine whether certain pathological groups and other groups at risk for neurological damage exhibited distinctive patterns of regional cerebral blood flow (rCBF) abnormality.

METHODS

HMPAO SPECT images obtained from six groups of subjects were compared with a normal cortical rCBF atlas, based on multivariate, voxel-by-voxel methods. In each case, a significance image was outputted, highlighting voxels with deficits of > or =3 s.d. of normal. Abnormal patterns were examined for the six groups, which comprised a further 40 normal volunteers, 18 diver controls, 50 divers with decompression illness (DCI), 34 boxers, 23 schizophrenics and 21 subjects with Alzheimer's disease.

RESULTS

The percentages of abnormal cortical voxels for each group were 0.41%, 0.53%, 1.38%, 1.05%, 0.56% and 2.24%, respectively. The percentages of images in each group with at least one lesion of 10 or more connected abnormal voxels and at least 10 lesions of two or more connected voxels, respectively, were 8% and 8% (normal volunteers), 17% and 11% (diver controls), 38% and 38% (divers with DCI), 41% and 29% (boxers), 26% and 13% (schizophrenics) and 90% and 48% (subjects with Alzheimer's disease). This suggests that multiple small lesions are as common as single large lesions for divers with DCI but not for patients with Alzheimer's disease or schizophrenia. Large lesions are located predominantly in the parietal and inferior temporal regions for Alzheimer's disease, in the parietal and occipital regions for divers with DCI and boxers and in the inferior frontal region for schizophrenia.

CONCLUSION

It appears that the groups considered here do have different rCBF patterns and that the significance image is a useful way of demonstrating this fact.

A voxel-by-voxel multivariate analysis of cerebral perfusion defects in divers with 'bends'

Past analysis of dysbaric-induced cerebral perfusion defects, demonstrated by 99Tcm-hexamethylpropylene amine oxime (99Tcm-HMPAO) single photon emission tomography in divers using quantitative and/or univariate techniques, has resulted i considerable controversy regarding the significance of these lesions compared to those seen in control subjects, correlations with clinical findings and the role of 99Tcm-HMPAO as a prognostic indicator in decompression sickness. We tried to address these problems by using a multivariate approach to a voxel-by-voxel analysis, involving the use of principal components, to determine ranges of normality in 50 reference controls. In subsequent images, abnormality was defined as 10 spatially connected voxels at an appropriate significance level of three standard deviations. The images of 50 divers with clinically diagnosed 'bends' were compared with those of a further 40 normal population controls with no previous history of loss of consciousness, head injury or dysbarism. The results showed that 19 of 50 divers with 'bends' and 3 of 40 population controls had significant perfusion defects, representing a significant difference between divers with dysbarism and population controls at the level P < 0.002. It is concluded that dysbarism causes significant cerebral cortical perfusion defects in affected divers both in 'silent' and symptomatic (clinically correlated) areas.

Optimization of factors affecting the state of normality of a medical image

The purpose of this paper is to examine the first stage of the diagnostic process in medical imaging, namely determination of the state of normality, and to attempt to optimize factors contributing to this stage. An image of a given type is defined as abnormal if it does not belong to the appropriate class of normal images. All images must be pre-processed involving image registration and normalization to align and scale the images with respect to each other. Normal ranges may be determined for each voxel (or other appropriate region) from a representative normal sample using univariate analysis, obtaining mean and standard deviation images, or multivariate analysis, which accounts also for normal patterns of variation (represented as principal components). For a new image, the variation from normality (in SDs) for each region may be determined. Since the spatial distribution of this parameter is thought to be relevant, connectivity of abnormal voxels was considered as a possible factor. For the purposes of this study, SPECT images indicating regional cerebral blood flow were used. Images from 50 normal subjects formed the normal sample. A further 40 normal subjects and 200 patients referred with suspected dementia were then analyzed using the normal ranges. ROC analysis, using number of SDs as a variable threshold, was used to optimize the factors. Normalization to global values followed by multivariate analysis using four or five principal components provided optimal discrimination. Connectivity of voxels emerged as an important factor, around 10 connected voxels being optimal for this study.

Cerebral perfusion and psychometric testing in military amateur boxers and controls

The objective was to compare two neurophysiological variables in active amateur boxers with non-boxing sportsmen. 41 boxers and 27 controls were given psychometric tests: 34 boxers and 34 controls underwent technetium-99m hexamethylpropyleneamineoxime single photon emission computerised tomography (Tc-99m HMPAO SPECT) cerebral perfusion scans. The controls performed better at most aspects of the psychometric tests. Boxers who had fought fewer bouts had a tendency to perform better at psychometric tests than those boxers who had fought more bouts. Tc-99m HMPAO SPECT cerebral perfusion scanning showed that controls had less aberrations in cerebral perfusion than the boxers. In conclusion, significant differences were shown in two neurophysiological variables between young amateur sportsmen who box and those who do not. The long term effects of these findings remain unknown.

A method for assessing the significance of abnormalities in HMPO brain SPECT images

METHODS

A normal atlas for HMPAO rCBF SPECT images was obtained from images of 53 normal controls. Following image registration and normalization, a mean image was extracted, while images representing correlated normal deviants were identified using principal component analysis. These images formed the "building blocks" of the atlas. For subsequent images, the atlas was used to create a "nearest normal equivalent" image, which was compared to a residual standard deviation image to determine the significance of deviations in the new image.

RESULTS

Images from 30 patients (10 with Alzheimer's disease; 12 with single or multiple infarcts; and 8 normals) were analyzed.

CONCLUSION

Using an optimal decision level, 10/10 patients with Alzheimer's disease and 11/12 patients with infarcts were correctly identified, with only one false-positive resulting. We utilized a database of images obtained from normal controls to create a normal atlas.

Case control study of cerebral perfusion deficits in divers using 99Tcm hexamethylpropylene amine oxime

In a preliminary report, Adkisson et al. (Lancet 1989; 2:119-121) used 99Tcm-hexamethylpropylene amine oxime (HMPAO) single photon emission computed tomography (SPECT) to provide evidence for cerebral perfusion deficits in 28 cases of dysbarism. The report caused concern because these deficits were found even in cases in which the clinical manifestations were limited to the spinal cord. To address this issue further, a case-control study of cerebral perfusion using 99Tcm-HMPAO SPECT is reported. Four groups of 10 subjects were studied: a) divers scanned on average 11 days after treatment of neurologic decompression illness, b) divers scanned 3-5 yr after treatment for neurologic decompression illness, c) diver controls, and d) population controls. All groups were matched for age, and the divers were further matched for general diving experience. The scans were randomized and reported blind to history. Despite a trend toward larger numbers of deficits in individuals with decompression illness, the 4 groups were statistically indistinguishable. Furthermore, no correlation was found between the location of the perfusion deficits and the clinical presentation. These results indicate that 99Tcm-HMPAO SPECT scanning requires further evaluation before clinical significance can be ascribed to perfusion deficits found in divers.

The use of induction in the design of an expert system for thyroid function studies

In this study, the role of induction in the design of an expert system for diagnosing thyroid disorders is evaluated. An expert system was first designed conventionally, based on interaction between a knowledge engineer and a thyroid specialist. This involved weighting three tests (T3, free T4 and TSH) according to the reliability of the test and the presence or otherwise of influencing factors. Compatibility was then tested with known ranges for the parameter values, and a diagnosis made of one of three possible outcomes (euthyroid; hypothyroid; hyperthyroid). Two expert systems were then induced using, firstly, a set of rules and, secondly, a sample set chosen from a database. These systems were then tested against the expert designed system. Both induced systems produced results which were superior to the expert designed system and, in addition, provided insight into the decision-making process. It is concluded that induction is very useful in the design of expert systems of this nature.

Factor analysis of dynamic structures (FADS) in the diagnosis of renal disease

Factor analysis of dynamic structures (FADS) has been used in the interpretation of dynamic scintigraphic studies since the technique was described by Bazin et al. (1980). This study was designed to analyse to what extent, if any, does physiological factor analysis of dynamic renal data really help the clinician and by how much the method improves the diagnostic accuracy when compared to deconvolution analysis and parenchymal transit time (PTT) measurements. One hundred and fifty patients who were clinically, biochemically and radiologically investigated for renal disease were included in the study. Fifty of these were found to have no clinical evidence of renal disease, 50 were diagnosed as having non obstructive kidney disease and 50 had evidence of renal obstruction. Data obtained from 99mTc-DTPA renography were processed using deconvolution (with PTTs) and physiological factor analysis and the results compared by ROC analysis. Clinically the information gained from factor analysis was superior to that obtained from deconvolution with PTT measurements in that a more accurate differentiation between an obstructive nephropathy and an obstructive uropathy was obtained. It is considered that physiological factor analysis enhanced the clinical information obtained from renography, increases diagnostic accuracy and obviates the need for diuresis renography.

Cerebral perfusion deficits in dysbaric illness

Decompression sickness (DCS) is usually categorised as type I (mild; peripheral pain, non-neurological) or type II (serious; neurological). Type II is regarded as predominantly a spinal cord disease with infrequent cerebral involvement. Cerebral perfusion was studied by injection of 99Tcm-hexamethylpropyleneamine oxime and single photon emission tomography in 28 divers with confirmed incidents of DCS and cerebral arterial gas embolism (CAGE). Cerebral perfusion deficits were present in all 23 cases of type II DCS and in all 4 cases of CAGE. No deficits were present in the single case of type I DCS. Type II DCS should be recognised as a diffuse, multifocal, central nervous system disease.

A perception experiment to assess the clinical accuracy of various methods of obtaining cardiac phase images

Five methods of obtaining cardiac phase (and phase-like) images are compared. These are single-harmonic Fourier phase imaging; time-to-minimum using a two-harmonic fit to each dixel; time-to-minimum using four weighted harmonics; composite factorial phase imaging; and individual factorial phase imaging. Polaroid prints of phase images for both gated equilibrium studies (using all methods) and first-pass studies (first and last methods only) were shown to observers who were asked to rate the images according to their confidence of an abnormality presenting. A receiver operating characteristic (ROC) analysis was performed. For gated studies composite factorial phase imaging appears to be best, while all methods are significantly better than single-harmonic Fourier phase imaging. For first-pass studies individual factorial phase imaging appears to be superior to single-harmonic Fourier phase imaging.

99Tcm-HMPAO single photon emission tomography in the diagnosis of cerebral barotrauma

Cerebral barotrauma, or the neurological manifestation of the "bends", is a relatively common disease of divers and aviators. To date, however, no-one has succeeded in demonstrating a cerebral or spinal cord lesion in vivo following a decompression incident, despite the presence of definitive clinical signs and symptoms of central nervous system involvement. This paper describes the use of 99Tcm-labelled hexamethylpropyleneamine oxime (99Tcm-HMPAO) with single photon emission tomography in a study of three individuals involved in driving accidents. All three suffered cerebral barotrauma during decompression and all exhibited clinical signs and symptoms of dysbarism to a varying degree. Imaging was performed at time intervals ranging from 2 h to several days following the incidents. The results showed well defined cerebral ischaemic lesions in all three subjects. We conclude that 99Tcm-HMPAO imaging provides a significant advance in locating and demonstrating cerebral lesions following barotrauma and will contribute greatly to our understanding of the pathophysiological processes involved.

Functional imaging in the early diagnosis of dysbaric osteonecrosis

Eight divers who developed permanent scintigraphic bone changes following dives to various depths took part in a study to determine the nature of these lesions. Only one of these divers had radiologically evident bone changes in his scintigraphic lesion. Dynamic scintigrams of the bones containing the lesions were obtained from all eight divers and functional images generated of both amplitude (osteoblastic activity) and accretion (microvasculature) rate constants. All had increased amplitude in the area of the scintigraphic lesion indicating continuing osteoblastic activity. Three divers showed a decreased accretion rate in the lesions, indicating impairment or absence of local microcirculation; one of these was the diver who showed radiological changes prior to the study and the other two subsequently developed radiologically evident osteonecrosis. It is concluded that functional images, generated from dynamic bone scintigrams, can successfully predict dysbaric osteonecrosis.

External monitoring of kidney transplant function using Tc-99m(Sn)DTPA

The purpose of this study was to evaluate the use of an external counting technique to provide daily monitoring of kidney transplant function by measuring the renal clearance of Tc-99m(Sn)DTPA. During the first few weeks following transplant, 15 patients had their renal clearance of Tc-99m DTPA measured daily over periods of 5-24 hr. Clearance rates were compared with daily plasma creatinine levels, and the effects of diurnal variation, drug treatment, and physical activity noted. The results show that any significant fall in clearance rate of chelate, indicating a rejection episode, preceded a rise in plasma creatinine levels by at least 24 hr. One episode of transplant failure presented as a sudden deterioration in clearance rate of chelate; in the others the change was more gradual but was still apparent within hours. It is considered that this noninvasive, low-dose, easy-to-perform technique is of considerable value in extended daily monitoring of renal function and is superior to standard daily or twice-weekly renography for the early detection of transplant rejection.

A comparison of three methods of assessing renal function

In a study of 100 patients referred for assessment of renal function a comparison is made between gamma camera computer assisted displays of 99mTc-DTPA(Sn) nephrograms, intra-venous urography (I.V.U.) and triple probe 131I-Hippuran renography. The computer processed data displays renal morphology and activity/time curves which are deconvolved enabling quantitative assessment of glomerular function to be made. Pattern recognition techniques for feature extraction are employed to facilitate classification of the curves. It is concluded that the computer processed data gives better results both in the recognition of morphological defects and in the indication and measurement of renal damage.

The advantages of 99mTc DTPA(Sn) in dynamic renal scintigraphy and measurement of renal function

The results of excretion urography (IVU) and dynamic renal scintigraphy using 99mTc DTPA(Sn) were compared in 109 urological patients. Computer analysis of the gamma camera data provided a reproducible, accurate, qualitative and quantitative assessment of renal function and was found to be superior to urography in the detection of morphological defects of the renal parenchyma and in the identification of early upper tract obstruction. The radio-isotope study is a safe, non-invasive investigation, easily performed on an out-patient basis, requires no prior preparation and is without significant radiation hazard to the patient.

Processing of liver dynamic studies with technetium-labelled sulphur colloid

The uptake of technetium-labelled sulphur colloid by the liver was investigated by monitoring 69 patients on a gamma camera/computer system. Following an intravenous injection 30 half-minute frames were collected and summed to give a composite view. Regions of interest were drawn round the liver and over the aorta and corresponding activity-time curves were formed. A simple physiological model has been assumed and two parameters, namely total uptake and rate of uptake, were shown to give fairly good separation between the classes of normal, cirrhosis, space occupying lesions, reticulosis and hepatitis. Furthermore the uptake rate-constant was also shown to be a useful indication of whether or not a reticulosis or hepatitis was in an acute phase. Principal components analysis was also applied to the liver curves producing two relevant components. However, a plot of the first against the second yielded no better separation of classes than that obtained by the model.

Principal components analysis as an aid to classification of renal dynamic studies

Four hundred renal dynamic studies obtained using 99mTc-(Sn) DTPA were classified clinically into four classes (normal, pre-renal lesion, intrarenal lesion and urinary tract obstruction). Principal components analysis was then applied to the kidney activity/time curves and yielded good class separation using only three components. The separation of normal and obstructed or damaged kidneys using only the first component was better than that obtained using the calculated mean transit time.

An intercomparison of computer assisted data processing and display methods in radioisotope scintigraphy using mathematical tumours

Several computer assisted processing and display methods are evaluated using a series of 100 normal brain scintigrams, 50 of which have had single 'mathematical tumours' superimposed. Using a standard rating system, or in some cases quantitative estimation, LROC curves are generated for each method and compared.

Urinary clearance of 113m In-DTPA and 99mTc-(Sn)DTPA measured by external arm counting

Single shot glomerular filtration rate measurements involving chelates (113mIn-DTPA, 99mTc-DTPA etc) assume direct loss from the plasma to urine via glomerular filtration and excretion. Inherent errors, due to considerable uptake of activity in tissue and uncertainty of complete bladder emptying are ignored and taking of half-hourly blood and urine samples involves patient discomfort. This paper describes a simple method of measuring urinary clearance of chelates using serial external arm counting which entails only an initial injection and takes into account tissue loss from plasma. The resultant plotted curve exhibits three phases, the first two depicting input and equilibration between plasma and tissue and the third and exponential part, which is a measure of the biological half-life of the chelate, being representative of the efficiency of renal glomerular filtration, the parameter to be measured. Results obtained, compared with single shot glomerular filtration rate measurements performed simultaneously, gave better correlation with clinical data including renography.