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Biomedical subjects

J Valeyre

Publications and source records attributed to J Valeyre.

At least 19 recordsLinked to original sources
PubMed1991

Comparison of phosphatase isoenzymes PAP and PSA with bone scan in patients with prostate carcinoma.

The aim of this study was to assess the diagnostic value of five biological markers--prostate acid phosphatase (PAP), prostate specific antigen (PSA), tartrate resistant (Tr-ACP), and tartrate labile (TI-ACP) acid phosphatases, and alkaline phosphatase bone isoenzyme (B-ALP)--for the detection of bone metastases in patients with prostate carcinoma. Using the Tc-99m HMDP bone scans of 80 patients scored from 0 (normal) to 2 (diffuse bone involvement) as the "gold standard," a receiver operating characteristic (ROC) analysis was performed. This method allows the determination of different threshold values (corresponding to different couples of sensitivity and specificity) for the assays. An ROC curve comparison was also performed. Results show that B-ALP is the best test for such detection (area under the ROC curve = 0.93; Spearman Rank correlation with bone scan r' = 0.81). Among the other markers, PSA was found to be the best (area under the ROC curve = 0.81; Spearman Rank correlation with bone scan r' = 0.58). In addition to the prostatic tumor markers (PSA and PAP), we suggest the use of the low-cost B-ALP assay in the follow-up of prostate carcinoma patients to determine the optimum moment to perform a bone scan. A normal result of this assay indicates a very low probability of bone metastasis; conversely, raising of B-ALP concentration must lead to a bone scan.

Acid Phosphatase↗
PubMed1991

[Prognostic value of exercise angioscintigraphy in coronary disease].

Multivariate survival analysis (MSA) was applied to 97 patients with coronary disease using the Cox model and a stepwise regression procedure. Seventeen variables including data based upon clinical examination, exercise testing (ET), and exercise angioscintigraphy (EAS) as well as coronary arteriography were studied in each patient. During the monitoring period (interval: 1-57 months), 38 patients sustained a cardiac event (recurrence of coronary disease or death). Neither resting left ventricular ejection fraction, nor coronary anatomy were significant prognostic variables. The only two variables identified by MSA were a variable of EAS: corrected ejection fraction at maximum exercise (p less than 0.008), and a variable of ET: maximum heart rate during exercise (p less than 0.03). This study shows that the prognosis of a coronary disease patient can best be assessed by two variables which are both exercise parameters.

Adult↗
PubMed1990

Bone scan and chemonucleolysis.

This study is based on 20 patients who underwent bone scanning before and after chemonucleolysis (CN) for a herniated lumbar disk. It shows that chymopapain, the proteolytic enzyme used for CN, does not induce early or late bone lesions of the adjacent vertebral plates. Abnormal uptake by one of the vertebral plates indicates a "chemical discitis." The pattern observed on the bone scan is different from the one presented by patients with bacterial spondylitis.

Chymopapain↗
PubMed1990

Cluster analysis for automatic image segmentation in dynamic scintigraphies.

An original and entirely automatic algorithm is proposed to select regions of interest (ROIs) on dynamic scintigrams. This algorithm is based on factor analysis and on cluster analysis. It consists of first extracting the orthogonal factor images of the series using factor analysis of correspondence. These factor images are then automatically segmented in ROIs using a hierarchical ascendant classification procedure. The distance used for the classification is the 'minimum added intra-class variance' distance. This algorithm has been implemented on a fast computer dedicated to nuclear medicine (Nodecrest Micas V system). The time of calculation on 1000 pixels from 40 images is less than 5 min when three factor images are used. This algorithm is validated using a numerical phantom and is illustrated using renal (99Tcm DTPA) and cardiac (equilibrium gated angiography) dynamic scintigraphies. The results show that the algorithm is able to recognize the bladder, the renal cavities and the renal parenchyma on the renal series, and the ventricules and the atria on the cardiac series.

Algorithms↗
PubMed1989

Immunoscintigraphy with indium-111 labeled monoclonal antibodies: the importance of a good display method.

A major drawback of In-111-labeled monoclonal antibodies (MoAb) is the presence of intense liver, renal, and bone marrow nonspecific activity. This makes the display of the images hardly optimal and their visual interpretation difficult. In this study, the "intrinsic color scale" (which consists of selecting the limits of the color scale as the highest and the lowest pixel value of the image) was compared to a new, simple algorithm for the determination of the limits of the color scale. This algorithm was based on the count density in the iliac crest areas. OC-125 or anti-CEA In-111 MoAb F(ab')2 fragments were used in 32 patients with suspected recurrence of ovarian (19 patients) or colorectal cancer (13 patients). Final diagnosis was assessed by surgery (21 patients), biopsy (five patients), or followup (six patients). A 10-minute abdomino-pelvic anterior view was recorded two days after injection. These views are displayed using the two methods and interpreted by two observers. Using their responses in each quadrant of the pelvis, the authors calculated two ROC curves. The comparison of the ROC curves showed better performances for the new method. For example, for the same specificity (73%), the sensitivity of the new method was significantly better (78% versus 68%). This result confirmed the importance of a good methodology for displaying immunoscintigraphic images.

Algorithms↗
PubMed1988

Superficial and deep lymphoscintigraphic findings before and after femoro popliteal bypass.

The aim of this work is to explore the patients operated on for a femoro popliteal bypass (FPB) with lymphoscintigraphy (LS) of the lower limbs. Data concerning 35 limbs from 33 patients operated on for a FPB have been included in a prospective study. Superficial and deep LS have been performed by injecting 74 MBq 99mTc-Rhenium Sulphide Colloid into the subcutaneous tissue of the first interdigital space and of the lateral malleolus region respectively. Both superficial and deep LS have been performed before and after surgery. A postoperative oedema was found in 17 of the 35 limbs. The value of the lymphatic flow indices and their variation after surgery do not significantly differ between the oedematous and non oedematous groups. Thirteen of the 17 limbs with oedema have presented an interruption of the lymphatic circulation or a diffuse activity outside the lymphatic vessels on the postoperative superficial and/or deep LS. This proportion is only 1/18 in the non oedematous group. The difference between the two groups is highly significant (P less than 0.001). By contrast, the proportion of lymph cyst does not differ significantly between the two groups. In conclusion, this study confirms the close relationship between the oedema following FPB and surgical damage to the lymphatics.

Colloids↗
PubMed1988

[Role of clinical manifestations, the exercise test and exertion angioscintigraphy in the diagnosis of coronary disease. A multivariate study].

Data of clinical examination, exercise electrocardiography and stress radionuclide angiography in 102 patients referred for assessment of chest pain was included in a logistic regression to optimise the diagnosis of coronary artery disease with coronary angiography as the reference investigation. None of the patients had other cardiac problems nor previous myocardial infarction. In the absence of symptoms exercise testing was continued until at least 80 p. 100 of the theoretical maximal heart rate was attained. Each patient was characterised by the value of the logistic function or probability of coronary artery disease. A threshold value corresponding to 80 p. 100 sensitivity was determined by the technique of ROC graphs. The significant variables were: a clinical variable--the type of chest pain as assessed by the clinical history; two radionuclide angiographic variables--the ejection fraction at peak effort and the corrected variation of ejection fraction between rest and stress, that is not taking into account possible decreases at the last increment of exercise. Coronary patients can be identified with an 80 p. 100 sensitivity and 77 p. 100 specificity on these criteria. This specificity is greater than that obtained by clinical examination and exercise electrocardiography alone (65 p. 100). Stress radionuclide angiography may therefore reduce the number of unnecessary coronary angiographies.

Adult↗
PubMed1988

[Quantification of chronic aortic insufficiency. Comparison between Doppler ultrasonic diagnosis and the radiocardiogram].

The objective of this study is to quantify aortic insufficiency by comparing pulsated Doppler ultrasonography and radiocardiography used as reference test. Since february 1986, 23 patients were tested with both techniques within 15 days. The Doppler ultrasonography enabled to quantify aortic insufficiency in 4 stages by semi-quantitative mapping of the regurgitation flow of the left ventricle (LV). Radiocardiography (RCG) has enabled the determination of the regurgitation fraction (RF), for each patient. A mean RF was calculated on RCG, for each Doppler stage. The FR difference between each Doppler stage is significant, especially between minimal and severe aortic insufficiency. RCG is the first stage of an isotopic examination, at rest and during stress; it may be followed by Doppler ultrasonography in monitoring patients with aortic insufficiency.

Adult↗
PubMed1988

Diagnostic value of stress radionuclide angiography in coronary artery disease: a comparison of different interpretation criteria.

In order to compare different criteria in the interpretation of stress radionuclide angiography (SRNA) 96 patients with suspected coronary artery disease (CAD) were investigated by both SRNA and coronary arteriography. The result of coronary arteriography was taken as the gold standard for the diagnosis of CAD. Left ventricular ejection fraction (LVEF) was measured at each step of the stress study using the equilibrium radionuclide technique. The diagnostic value of eight interpretation criteria based on the evolution of global LVEF during stress were compared with each other, using the ROC technique. The best diagnostic criterion proved to be the normalized increase of LVEF proposed by Goris. The most commonly used criteria, LVEF increase and LVEF measured at maximal exercise, were not optimal. In the whole population of patients, the best criterion had a sensitivity of 85% for a specificity of 80% and a specificity of 83% for a sensitivity of 80%. In the population, following exclusion of patients with preceding myocardial infarction, the specificity was 74% for a sensitivity of 80% and a sensitivity of 74% for a specificity of 80%. Thus, the choice of interpretation criteria is very important in order to optimize the sensitivity and specificity of this diagnostic test.

Angina Pectoris↗
PubMed1987

ROC analysis in radioimmunoassay: an application to the interpretation of thyroglobulin measurement in the follow-up of thyroid carcinoma.

This study is an application of the ROC technique to the determination of threshold values (TV) for the interpretation of serum thyroglobulin (Tg) measurements in the follow-up of differentiated thyroid cancer. Serum Tg was assayed using the Henning kit in 1466 samples from 245 individuals. A local or distant recurrence was assessed by clinical examination, radiological and scintigraphic investigations, and was present in 23 patients. The measurements were divided into four groups: 1) measurements performed less than 6 months after thyroidectomy; 2) measurements performed more than 6 months after thyroidectomy; 3) measurements performed during the suppression of pituitary secretion; 4) measurements performed during withdrawal of the substitutive therapy. An ROC curve was calculated for each group and for each curve three TVs were determined: TV1, TV2, and TV3 corresponding to a high sensitivity, a high specificity and a high sum of sensitivity and specificity respectively. TV1 is 3.12 micrograms/l in the four groups. TV2 is 44 micrograms/l, 19 micrograms/l, 11 micrograms/l and 30 micrograms/l, in the first, second, third and fourth groups respectively. TV3 is 35 micrograms/l in the first group, 3.12 micrograms/l in both the second and third groups and 30 micrograms/l in the fourth group. When the classical method allows the determination of only one threshold value, the ROC technique allows us to determine threshold values adapted to both the patient clinical status and the chosen sensitivity or specificity.

Follow-Up Studies↗
PubMed1987

A new approach to image subtraction in immunoscintigraphy: preliminary results.

Recently proposed image comparison software is applied to immunoscintigraphy. The software performs geometric and gray level registration of two images and generates an image of the statistically significant differences. It permits the comparison of scintigraphic images recorded at different times. It is used to subtract 113mIn and 111Inphytate colloid liver scans and early (blood pool) images from 131I or 111In-monoclonal Ab images and to compare Ab images recorded at different times. Using the procedures made possible by this software, only images recorded using the same radionuclide or using radionuclides of about the same energy are compared. Anti CEA, 19-9 and OC 125 F(ab)2 fragments labeled with 131I or 111In are used in 32 patients with 47 demonstrated recurrences or metastases of colorectal or ovarian cancers. The overall sensitivities of the unprocessed and processed images are 25/47 and 41/47 respectively. The improvement in sensitivity is particularly high in the liver when In labelled Ab are used. This technique improves the contrast of the images, but the interpretation must take into account the components of the non target activity (kidney, bone marrow, colon...) which are not removed by the image subtraction method.

Antibodies, Monoclonal↗
PubMed1987

Improvement of the amplitude image through statistical filtering.

In order to perform automatically the thresholding of the amplitude image obtained by phase analysis, a filter based on the probability density of the amplitude is proposed. It generates the image of the significant amplitude by setting to zero the amplitude if its square is lower than 4a0 log(1/alpha)/N where a0 is the mean of the signal, alpha the risk of error and N the number of frames. The power of the test is discussed and the modification of the filter for pre-processed data is provided.

Filtration↗
PubMed1987

[Value of exploring the deep lymphatic system of the lower limbs using lymphoscintigraphy. Preliminary study of 18 patients with arteritis].

Lymphoscintigraphy of lower limbs generally involves bilateral subcutaneous injection of a radioactive colloid into the first or second interdigital space: only the superficial internal saphenous pathway is visualized in this way (superficial lymphoscintigraphy: SL). However, the external saphenous and deep pathways can be explored by an external retromalleolar injection as demonstrated in radiology. Isotopic exploration of the external saphenous pathway and deep lymphatics (deep lymphoscintigraphy: DL) was carried out in 18 patients with arteritis also investigated by SL. The study forms part of a prospective trial of edema developing after femoro-popliteal shunts. The deep lymphatics are correctly and easily visualized, and in about 20% of cases there exist anomalies of distribution of superficial or deep lymphatic flow, morphologic anomalies developing postoperatively in one pathway only, or in both pathways. DL is a simple, reliable method of investigation of deep lymphatics, and complete exploration of lymphatics of lower limbs should include both SL and DL.

Aged↗
PubMed1986

Comparison of phase analysis with factor analysis in equilibrium gated radionuclide angiography.

This study is the intercomparison of phase analysis (PA), factor analysis of dynamic structures (FADS) and Karhunen-Loeve analysis (KLA) in the diagnosis of regional wall motion abnormalities, RWMA, of the LV. One hundred and twenty eight patients with proven or suspected CAD have been investigated by both X-ray angiography and radionuclide equilibrium angiography performed in the LOA view. FADS and KLA are performed twice, once on the whole-image (WI-FADS, WI-KLA), and once on the LV ROI (LV-FADS, LV-KLA) as suggested by Pavel. Resulting images and factors are interpreted by a well trained observer. In an attempt to quantify LV-FADS images, two numeric parameters, P1 and P2, are defined. They measure the relative weight of the so-called ventricular factor for 2 and 3 factor analysis, respectively. A ROC curve is calculated for each method, taking X-ray angiography as the gold-standard. The areas under the ROC curves are estimated by the maximum likelihood method and are compared using a test described by Hanley which takes into account the correlation between the responses. The areas are: 0.90 for PA, 0.84 for WI-FADS, 0.86 for LV-FADS, 0.83 for WI-KLA, 0.86 for LV-KLA, 0.65 for P1 and 0.72 for P2. The observed differences are significant (at 5% level) between PA and WI-FADS and between FA and WI-KLA; whereas they are not between PA and LV-FADS, between PA and LV-KLA and between LV-FADS and LV-KLA. The diagnostic value of the two numeric parameters is poor.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

The objective evaluation of the phase image: a comparison of different automated methods.

One hundred and twenty eight patients with suspected or proven CAD were investigated using both X-ray ventriculography and equilibrium gated radionuclide angiography. In order to diagnose regional wall motion abnormalities, the parametric images obtained by Fourier analysis of the radionuclide images were analysed by different automated methods based on the measurement of the homogeneity of the phase values within the LV ROI. The effect of a diastolic frames exclusion, smoothing the original data, weighting the phase histogram, using Bacharach's error corrected phase distribution functions, using different descriptors of the spread of the phase histograms or distribution functions were tested. Using the results of the X-ray examination as the gold standard, ROC curves were plotted for each method. The ROC curves were modelled by a binormal model using the maximum likelihood method. Statistical tests were applied on the area under the ROC curves. The results show that the diagnostic value of the automated methods depends mainly on the way the histograms or distribution functions are described and to a lesser extent on the type of histograms or distribution functions used. The best result is obtained after smoothing, diastolic frames exclusion, weighting the phase histogram by the amplitude and describing it by its standard deviation. Nevertheless, this result is not significantly different from the result obtained by visual analysis of the phase and amplitude images.

Adult↗