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Biomedical subjects

J C Liehn

Publications and source records attributed to J C Liehn.

At least 19 recordsLinked to original sources
PubMed1992

Superimposition of computed tomography and single photon emission tomography immunoscintigraphic images in the pelvis: validation in patients with colorectal or ovarian carcinoma recurrence.

A method of superimposing computed tomography (CT) and immunoscintigraphic (IS) single photon emission tomography (SPET) slices is presented and has been applied to 10 patients with suspected cancer recurrence. IS was performed with carcinoembryonic antigen (CEA)-specific indium-111 monoclonal antibodies (MoAbs) in 5 patients with colorectal cancer, and with OC125 111In-MoAbs in 5 patients with ovarian cancer. All patients had an abnormal CT image result in the pelvis, which was interpreted 5 times as recurrence, once as doubtful and four times as scar fibrosis. Recurrence was subsequently proven in all patients. Bone scintigraphy (BS) SPET was recorded at the same time as IS. No special technique was used during BS, IS or CT acquisition. CT images were fed into a computer using a CCD camera. Using the internal anatomical landmarks provided by the pelvic bone structures seen on CT and BS, an operator had to select corresponding fiducial points, which were used by the software to register the images. The final results were CT-BS and CT-IS superimposed images. CT-BS images were used for quality control. In all patients, the inspection of CT-BS and CT-IS showed that the registration process is accurate and assists in the co-interpretation of CT and IS images.

Colorectal Neoplasms↗
PubMed1992

Volume rendering and bicolour scale in double isotope studies: application to immunoscintigraphy and bone landmarking.

Combining the volume rendering and bicolour visualization techniques is proposed as an aid in interpreting single photon emission tomography (SPET) immunoscintigraphy (IS) recorded simultaneously with SPET bone landmarking (BL). The combination helps in localizing abnormal monoclonal uptake and in differentiating it from a physiological radioactivity distribution. The so-called rendered images (RIs) are obtained in both IS and BL studies according to a depth- weighted maximum activity projection algorithm. Fused BL and IS RIs are constructed by a simple, pixel by pixel addition. They are displayed using a bicolour grey-red scale, which makes it possible to visualize both studies by a transparency effect. This method was applied to patients suspected of suffering colorectal or ovarian cancer recurrences, in whom monoclonal antibodies against carcinoembryonic antigen, B72-3 or OC125 labelled with indium-111 were used.

Bone and Bones↗
PubMed1992

Correlative imaging study in the diagnosis of ovarian cancer recurrences. The INSERM Research Network (Nantes, Rennes, Reims, Villejuif, Saclay), France.

A correlative imaging study was carried out in 61 female patients previously treated for ovarian carcinoma. Upon suspicion of recurrence, abdominopelvic immunoscintigraphy (IS) using F(ab')2 fragments of indium-111-labelled OC 125 monoclonal antibody was performed in all patients, Ultrasonography (US) and computed tomography (CT) were performed 53 and 37 times, respectively. The diagnostic accuracy of the different imaging techniques was studied per site (abdomen and pelvis) and per patient. The diagnostic accuracy of planar scintigraphy (PS) was slightly lower than that of emission computed tomography (ECT): 66% vs 73% for abdomen, 65% vs 72% for pelvis, and 78% vs 84% in analysis per patient. The accuracy of IS (PS and ECT combined) was markedly better than that of US and CT for abdomen (IS = 73%; US = 30%; CT = 47%), pelvis (IS = 73%; US = 37%; CT = 52%) and analysis per patient (IS = 85%; US = 43%; CT = 59%). The results of IS and morphological imaging techniques (MIT: US and/or CT) were correlatively analysed with the frequency of recurrence. When IS and MIT were both negative, the frequency of non-recurrence was 14/23 for abdomen, 7/12 for pelvis and 8/13 in analysis per patient. On the other hand, when both IS and MIT were positive, the frequency of recurrence was high (9/9 for abdomen, 17/21 for pelvis and 24/26 for analysis per patient). It was also found that a positive IS associated with a negative MIT was still highly suggestive of recurrence (17/21 for abdomen, 16/22 for pelvis and 17/19 for analysis per patient).(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1992

Visualization of myocardial infarction 6 h after injection of 111In-antimyosin antibodies using a blood pool subtraction technique.

111In-antimyosin antibodies are capable of visualizing myocardial infarction (MI). Because of slow blood clearance, images are usually recorded 24 or 48 h postinjection. In this pilot study, a blood pool subtraction technique, which makes it possible to visualize MI 6 h postinjection, is validated. Twenty-five patients with proven MI (16 anterior, 9 inferior) were imaged a few minutes, 6 and 24 h after an injection of 111 MBq 111In-labelled antimyosin antibodies. Three planar views are obtained each time. Using software which performs the geometric registration, the grey level normalization and the subtraction of images, the blood pool image (obtained a few minutes postinjection) is subtracted from the 6 h image. The resulting image is the blood pool corrected 6 h image. The 24 h images and the blood pool corrected 6 h images were interpreted blindly and the number of correct, incorrect and impossible MI localizations was counted. The number of correct localizations is 19/25 for the standard 24 h images and 22/25 for the blood pool corrected 6 h images. Then, with this blood pool subtraction method, it is possible to visualize MI 6 h postinjection. This has to be taken into account when discussing the role of antimyosin scintigraphy in the management of patients with MI.

Antibodies, Monoclonal↗
PubMed1992

[Role of adrenocortical scintigraphy in the exploration of incidentally discovered tumors].

To determine the utility of adrenocortical scintigraphy with I131-6 beta-iodomethyl-19-nor-cholesterol (NP59) in incidentally discovered adrenal masses, we studied 12 patients with a unilateral adrenal mass and without other primary tumors or signs of pheochromocytoma or hyperfunctioning adenoma. Ten patients had an adenoma (size: 12 to 35 mm), the diagnosis was made by surgery or by no change in size on repeated CT scans. The NP59 scintigraphy showed an increased uptake on the side of the tumor in 8 cases with a decreased uptake of contra-lateral gland in 7 cases. Hormonal investigations of glucocorticoid function suggested supranormal or fluctuant cortisol secretion in 5 cases as assessed by moderately elevated urinary free cortisol or by incomplete dexamethasone suppression test. These abnormalities disappeared after surgery. Two patients had normal bilateral uptake of NP59, the sizes of the tumors were 12 and 20 mm. Two patients had an extra-adrenal tumor. The NP59 scintigraphy showed a moderately decreased uptake on the side of the hematoma of one patient and a compression of the normal adrenal by ganglioneuroma of the other patient. Our results and those of other authors suggest that positive NP59 scintigraphy could confirm the cortical nature of an incidentally discovered adrenal mass, probably an adenoma that must be followed up morphologically and functionally. No uptake by a tumor greater than 2 cm suggests a primary malignancy or extra-adrenal origin which must be diagnosed by invasive methods.

Adenoma↗
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

Multi-centre immunoscintigraphic study using indium-111-labelled CEA-specific and/or 19-9 monoclonal antibody F(ab')2 fragments.

Six European nuclear medicine centres performed immunoscintigraphy first retrospectively in 34 patients using indium-111-labelled carcinoembryonic antigen (CEA)-specific and/or 19-9 F(ab')2 fragments. Results for sensitivity and specificity in tumour sites were 94% and 87%, respectively, for the pelvis and 73% and 100% for the extrahepatic abdomen. A second prospective series concerned 58 other patients previously operated on for colorectal adenocarcinoma (27 colon, 31 rectum). Two-thirds of these patients had a suspected recurrence signalled by an isolated rise in tumour markers, and 46 patients examined by immunoscintigraphy, X-ray computed tomography and ultrasonography were found to have a recurrence (a total of 62 tumour sites). Sensitivity and specificity with immunoscintigraphy were 90% and 97%, respectively, for the pelvis and 62% and 95% for the extrahepatic abdomen. For 29 patients injected with CEA-specific fragments, sensitivity was 90% and specificity 94% for the pelvis. For 25 patients injected with 19-9 fragments, pelvic sensitivity and specificity were 80% and 100%, respectively, whereas sensitivity for the extrahepatic abdomen was only 29% since several cases of peritoneal carcinosis were not visualized. In the prospective series, comparison of the three imaging techniques for all tumour sites (including liver and in 5 cases thorax) gave a sensitivity and specificity of 82% and 91%, respectively, for immunoscintigraphy, 52% and 95% for X-ray computed tomography and 59% and 100% for ultrasonography. These results thus confirm the advantage of using 111In-labelled CEA-specific or 19-9 to visualize and localize recurrences of colorectal cancer.

Adenocarcinoma↗
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

Image registration in electron microscopy: application of a robust method.

The geometric registration of two electron microscopic images generally is performed by maximizing the cross-correlation coefficient between them. We show that a new similarity measure (the number of sign changes) is useful for performing simultaneously geometric and gray-level registration. This method is robust, which means that it provides a good estimation of the parameters even in the presence of outliers that cannot be described by the registration model.

Computer Simulation↗
PubMed1988

Improvement of parathyroid Tl-Tc scintigraphy by using a new image subtraction method.

Forty five thallium-technetium parathyroid scans were performed preoperatively in patients with a high suspicion of parathyroid adenoma or hyperplasia. The patients were imaged after sequential IV injection of 201Tl-thallous chloride (74 MBq) and 99mTc-pertechnetate (222 MBq) using a gamma camera with a pinhole collimator. According to surgical findings, the prevalence of parathyroid abnormalities was 42/45: single (34 patients) and double (1 patient) adenomas, hyperplasia (7 patients, 16 hyperplastic glands). Three methods of analysis of scintigraphic images were compared. Method one was the visual comparison of the thallium and the technetium images. Method two used the subtraction image obtained after normalisation. Method three used a new image comparison method which performs the geometric and gray level registrations of the two images and generates the image of the significant differences. Three observers were involved in the evaluation procedures. Surgery and histological examinations were taken as the gold standard. Results show that the sensitivity is increased by applying method three. The interobserver reproducibility of the results is also higher for method three. We conclude that an adequate image subtraction technique significantly increases the diagnostic value of parathyroid scintigraphy.

Adenoma↗
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

Multivariate analysis in solitary cold thyroid nodules for the diagnosis of malignancy.

A stepwise logistic regression (SLR) was performed on 162 patients with a solitary and cold thyroid nodule in order to discriminate between malignant and benign lesions. Sixteen variables were recorded for each patient. The predictions of the logistic regression model were compared to the histological diagnoses in order to evaluate the accuracy of the classification. The value of the logistic function (LF) was calculated for each patient. Using the ROC curve approach, an optimum threshold value (OTV) corresponding to a 100% sensitivity was defined. The classification obtained with the OTV was validated using a cross-validation procedure (CVP). The significant variables selected by the SLR are (from the most significant to the least significant): cytologic result, sex, irregular margin on the Tc scintigraphy and homogeneity on the ultrasound examination. The OTV corresponds to a specificity of 73% for a sensitivity of 100%. The specificity and the sensitivity obtained with the CVP are 73% and 96% respectively. In conclusion, the classification of the patients according to the value of the LF is a highly accurate diagnostic procedure.

Adult↗
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

[Thallium-technetium scintigraphy for presurgical localization of parathyroid adenomas and hyperplasia].

The purpose of this study was to assess the value of parathyroid Thallium 201-Technetium 99m scintigraphy in 45 patients with hyperplasia or parathyroid adenomas with or without associated thyroid abnormalities. The prevalence of parathyroid abnormalities found during examination was 42/45: 36 adenomas (35 patients) and 16 hyperplasias (7 patients). Seventeen patients (38%) had thyroid abnormalities. The sensitivity and specificity of the three image analysing methods (visual analysis, simple subtraction, sophisticated subtraction) were determined by assessing answers given by 3 observers. The population was divided into 6 groups: adenomas and hyperplasias with (group I, n = 42) or without (group II, n = 25) thyroid abnormalities, adenomas alone with (group III, n = 35) or without thyroid abnormalities (group IV, n = 22), hyperplasias alone with (group V, n = 7) or without thyroid abnormalities (group VI, n = 5). The highest overall sensitivity was obtained, whichever the group, by applying the sophisticated image subtraction technique; for any given method, the best results were observed in the group comprising adenomas alone, especially without associated thyroid abnormalities. On the other hand, in the groups comprising hyperplasias alone, sensitivity was low. This leads us to conclude that, together with ultrasonography, parathyroid scintigraphy is currently the best preoperative technique for localizing parathyroid adenomas, even in the presence of associated thyroid abnormalities. However this must be carried out in conjunction with a sophisticated image subtraction technique.

Adenoma↗