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R Bares

Publications and source records attributed to R Bares.

At least 55 records · Page 3Linked to original sources
PubMed1997

Fluorine-18 fluorodeoxyglucose positron emission tomography in the differential diagnosis of pancreatic carcinoma: a report of 106 cases.

The aim of this study was to evaluate fluorine-18 fluorodeoxyglucose positron emission tomography ([18F]FDG PET) as a tool for the differential diagnosis of pancreatic carcinoma while taking into account serum glucose level. A group of 106 patients with unclear pancreatic masses were recruited for the study. PET was performed following intravenous administration of an average of 190 MBq [18F]FDG. Focally increased glucose utilisation was used as the criterion of malignancy. In addition, the "standardised uptake value" (SUV) was determined 45 min after injection. Carcinoma of the pancreas was demonstrated histologically in 74 cases, and chronic pancreatitis in 32 cases. Employing visual evaluation, 63 of the 74 (85%) pancreatic carcinomas were identified by PET. In 27 of the 32 cases (84%) of chronic pancreatitis it was possible to exclude malignancy. False-negative results (n=11) were obtained mostly in patients with raised serum glucose levels (10 out of 11), and false-positives (n=5) in patients with inflammatory processes of the pancreas. Thus PET showed an overall sensitivity of 85%, a specificity of 84%, a negative predictive value of 71%, and a positive predictive value of 93%. In a subgroup of patients with normal serum glucose levels (n=72), the results were 98%, 84%, 96% and 93%, respectively. Quantitative assessment yielded a mean SUV of 6.4+/-3.6 for pancreatic carcinoma as against a value of 3.6+/-1.7 for chronic pancreatitis (P<0.001), without increasing the diagnostic accuracy. This shows PET to be of value in assessing unclear pancreatic masses. The diagnostic accuracy of PET examinations is very dependent on serum glucose levels.

Adenocarcinoma↗
PubMed1997

Fasting improves discrimination of grade 1 and atypical or malignant meningioma in FDG-PET.

UNLABELLED: We investigated the use of PET with 2[18F]fluoro-2-deoxy-D-glucose (FDG) to discriminate between atypical or malignant and grade 1 meningiomas. The influence of fasting state and high-dose corticosteroid medication was analyzed retrospectively. METHODS: Preoperative PET scans of 75 patients with suspected diagnosis of intracranial meningioma were evaluated using standardized uptake values (SUV) and tumor-to-contralateral gray matter ratios (TGR) of FDG uptake. Fifty-one of 75 patients fasted before the PET scan, and 27 of 75 patients were studied under high-dose corticosteroid medication. Eighteen tumors had recurred. PET results were compared to histopathological grading. RESULTS: PET correctly identified 8/9 atypical or malignant meningiomas and 58/66 grade 1 meningiomas using TGR and a threshold of 1.05 in primary meningioma and 0.85 in tumor recurrence. This corresponds to a specificity of 0.88 for the detection of higher tumor grading. Specificity was significantly higher in fasting compared to nonfasting subjects (0.96 versus 0.73; p < 0.025). SUV quantification lead to a reduced specificity of 0.77 at the same level of sensitivity. The only false-negative PET finding occurred in a recurrent meningioma, which had been operated on four times before. CONCLUSION: Overnight fasting before injection is needed to improve the diagnostic accuracy of FDG-PET for noninvasive metabolic grading of meningioma. Hyperglycemia in nonfasting patients and in diabetic patients may lead to overestimation of meningioma grading.

Adolescent↗
PubMed1997

[A method for combined scatter and attenuation correction without transmission measurement for myocardial SPECT with 99m-Tc binding].

AIM: A new strategy is introduced for a double-head gamma-camera to calculate and to correct for attenuation distribution from count rates of backscattered radiation of 99mTc in the human thorax/myocardium setting. The intention was to gain segmented and calibrated images of distribution employing the structures of lungs and other tissues, so that attenuation may be subsequently corrected by the method of Chang METHODS: Acquisition was done simultaneously in three energy window for 99mTc to receive both emitted and scattered radiation. The acquire projections were used to calculate the attenuation distribution and to execute a scatter correction by the method of Ogawa et. al. By measuring phantoms and evaluating a set of patient studies, quality for both of the approaches towards attenuated distribution and the quality of attenuation correction was tested and an optimal setting for parameters involved was selected. RESULTS: The procedure adequately approaches the correction for both emitted and scattered radiation in SPECT, as experienced in phantom and patient studies. Clinical usefulness was preliminary documented in selected cases. In normal perfusion, distribution was more homogeneous. Perfusion defects appeared more definitive. Problems occurred in high adjacent non-target activity (e.g., in the gallbladder) and with low count rate statistics. CONCLUSION: Myocardial 99mTc MIBI SPECT may be effectively corrected for both attenuation a scatter without an additional transmission device.

Heart↗
PubMed1996

[Results of positron emission tomography with fluorine-18 labeled fluorodeoxyglucose in differential diagnosis and staging of pancreatic carcinoma].

Although the detection of pancreatic carcinoma has been considerably improved by recently developed imaging procedures, differential diagnosis between cancer and benign tumor masses, as well as lymph node staging, is still difficult. In vivo evaluation of regional glucose metabolism by means of positron emission tomography (PET) and fluorine-18-labelled fluorode-oxyglucose (FDG) is a new approach utilizing metabolic instead of morphological tumor properties for diagnosis. PATIENTS AND METHODS. A total of 85 patients with suspected pancreatic carcinoma were investigated by FDG-PET prior to surgery. Static PET scans were evaluated visually as well as quantitatively, taking increased FDG uptake as a sign of malignancy. PET results were correlated with intraoperative findings and histopathology of surgical specimens. RESULTS. Forty-seven out of 55 (85%) malignant tumors and 23 out of 30 (77%) benign lesions were correctly classified by PET. Lymph node metastases were present in 31 patients, 19 of them (61%) positive in PET. In 7 our of 13 (54%) patients with liver metastases, PET detected hypermetabolic lesions. False-negative findings were mainly due to disturbance of glucose metabolism in diabetic patients, while most false-positive results could be attributed to acute inflammatory lesions in chronic pancreatitis. CONCLUSIONS. Our results indicate that classification of pancreatic masses can be improved by use of FDG-PET, which might lead to a reduction of unnecessary laparotomies in patients with benign or incurable disease.

Blood Glucose↗
PubMed1996

Prostate-specific antigen as a marker of bone metastasis in patients with prostate cancer.

OBJECTIVE: Staging in patients with newly diagnosed untreated cancer of the prostate has significant ramifications on the management of the disease. Currently measurement of the serum prostate-specific antigen (PSA) concentration and radionuclide bone scan are two important procedures in the metastatic workup of these patients. We retrospectively evaluated the efficacy of PSA as a staging marker to discriminate prostate cancer patients with bone metastases from those without bone metastases. MATERIALS AND METHODS: In a retrospective study 158 prostate cancer patients with (n = 21) and without (n = 137) bone metastases were analyzed. In all patients the initial PSA measurement as well as the radionuclide bone scan were evaluated. RESULTS: Patients with bone metastases demonstrated a median serum PSA concentration of 151 ng/ml and only 1 patient revealed a serum PSA concentration of <10 ng/ml. This resulted in a negative predictive value of 98%. In addition 67% of these patients demonstrated a serum PSA concentration of >100 ng/ml, which resulted in a positive predictive value of 74% and an overall accuracy of 92%. CONCLUSION: The serum PSA concentration seems to provide useful information with regard to the presence of bone metastasis in patients with newly diagnosed cancer of the prostate. A serum PSA value of <10 ng/ml nearly excludes bone metastases, whereas a serum PSA value of> 100 ng/ml is highly predictive of bone metastases.

Adult↗
PubMed1996

Metabolic imaging of untreated prostate cancer by positron emission tomography with 18fluorine-labeled deoxyglucose.

PURPOSE: We evaluated positron emission tomograph (PET) with 18fluorine (18F)-labeled deoxyglucose for metabolic grading of untreated primary prostate cancer, and differentiation of benign and malignant prostatic disease. MATERIALS AND METHODS: A total of 48 patients with untreated prostate cancer of different stages and 16 with histologically confirmed benign prostatic hyperplasia (BPH) underwent static PET after intravenous injection of 150 to 300 MBq. 18F-deoxyglucose. 18F-deoxyglucose accumulation was quantitated by calculating differential uptake ratios and prostate-to-skeletal muscle ratios. RESULTS: Low 18F-deoxyglucose uptake was noted in the majority of primary tumors (81%). 18F-deoxyglucose accumulation did not correlate with increasing tumor grade or stage. There was a significant overlap in uptake values in BPH and malignant prostatic disease. A trend towards statistical significance was noted with lower prostate-to-skeletal muscle ratios in patients with BPH (p < 0.07). Increased 18F-deoxyglucose accumulation was detected in some patients with BPH and malignant prostatic disease, as well as in those with lymph node and bone metastases of prostate cancer. CONCLUSIONS: 18F-deoxyglucose PET does not allow for metabolic labeling in the majority of untreated primary prostate cancers. BPH and primary prostate cancer cannot be reliably differentiated on the basis of PET. Increased 18F-deoxyglucose accumulation occurs in some primary prostate tumors and in metastatic deposits of prostate cancer.

Antimetabolites↗
PubMed1996

[Clinical value of positron emission tomography (PET) in oncologic questions: results of an interdisciplinary consensus conference. Schirmerreschaft der Deutschen Gesellschaft for Nuklearmedizin].

AIM: The purpose of the present paper is to assess clinical value of PET in oncology on the basis of published studies. METHODS: Clinical value of PET in oncology was evaluated by a panel of recognized experts in the framework of an interdisciplinary consensus conference. On the basis of PET studies, well documented in the international literature, the value of PET for solving clinical questions was classified according to the following categories (classes 1a, 1b, 2a, 2b, 3): "appropriate" (1a), "mostly acceptable" (1b), "helpful" (2a), "value as yet unknown" (2b), "useless" (3). RESULTS: 2-fluorodeoxyglucose (FDG) acts as the radiopharmaceutical of choice for PET in clinical oncology. PET is indicated (1a) for diagnosing relapse in high grade glioma (FDG) or low grade glioma (C-11 methionine or F-18 fluorotyrosine), differential diagnosis of solitary peripheral pulmonary nodules in high risk patients and for diagnosis of pancreatic carcinoma. PET may be clinically used (1b): In "low-grade" glioma, search for unknown primary in head and neck tumors, suspicion of relapse in non-small cell bronchial carcinoma (NSCBC) and colorectal carcinoma, lymphnode staging in NSCBC, pancreatic carcinoma, muscle invasive bladder carcinoma and testicular cancer. Staging of Hodgkin's disease (HD, stage I/II vs III), early therapy control in patients with a residual mass or suspicion of relapse in HD and in high grade NHL, lymph node staging and search for distant metastases in malignant melanoma (Breslow > 1.5 mm), search for lymph node or distant metastases in differentiated thyroid cancer with elevated hTG and a negative radioiodide whole body scan. Many further indications are emerging, but are not yet sufficiently well documented in the literature. For most indications beside scientific studies, an individual cost benefit utility evaluation by the responsible physician is recommended. CONCLUSION: Metabolic imaging of PET provides for many principle advantages compared to conventional anatomically based cross sectional imaging. For routine use in oncology a detailed assessment of specific efficiency of PET is indicated.

Female↗
PubMed1995

Effects of intravenous ketamine on gastrointestinal motility in the dog.

OBJECTIVE: The purpose of this trial was to clarify the effects of intravenous ketamine at anaesthetic and sub-anaesthetic dosages on gastrointestinal motility. DESIGN: 20 beagles (group 1: 3 mg/ketamine/kg/h, n = 10; group 2: 30 mg ketamine/kg/h, n = 10), were investigated. Gastric emptying (nuclide gastric emptying studies, liquid and semi-solid test meal), intestinal transit time (Hydrogen breath test with lactulose) and intestinal motor function (perfusion manometry with 8 measuring ports) were determined. As a control condition, the tests were performed on all dogs in the two groups during infusion of physiological saline solution. RESULTS: No significant differences in the motility patterns were present between 3 mg ketamine/kg/h and the control condition. For group 2, a moderately significant (p < 0.05) increase in the interdigestive motility index was observed for 30 mg ketamine/kg/h. However, this did not change the transit criteria. There was no significant difference between ketamine and control condition tests with regard to cycle and phase lengths or the propagation rate of the activity front. CONCLUSIONS: We conclude that ketamine provokes no basic changes in gastrointestinal motility, at either sub-anaesthetic doses. It can therefore be used to advantage in the continuous postoperative analgesia of intensive care patients, where repeated interventions are necessary and no cardiopulmonary contraindications are present.

Anesthetics, Dissociative↗
PubMed1995

Metabolic mismatch of septal beta-oxidation and glucose utilization in left bundle branch block assessed with PET.

Preserved septal uptake of the new long-chain fatty acid analog [18F]FTHA was found in a patient with three-vessel disease, a history of previous anterior myocardial infarction and left bundle branch block (LBBB), despite severely decreased septal [18F]FDG uptake that suggested scarred tissue. Nearly absent [19F]FDG uptake in the septum could not be explained by concordant reduction of septal perfusion as assessed by 99mTc-MIBI SPECT. These data may point to divergent metabolic effects of the conduction abnormality in LBBB with consecutively reduced septal exogenous glucose utilization but unaffected septal beta-oxidation.

Aged↗
PubMed1995

[MRI and oncoscintigraphy with 99m-Tc-MIBI in the follow up of thyroid cancer].

Magnetic resonance imaging (MRI) and 99mTc-MIBI oncoscintigraphy are new procedures for the detection of recurrent differentiated thyroid cancer. We evaluated the utility of both techniques compared to ultrasonography, radioiodine scanning, and measurement of serum thyroglobulin in patients with (n = 21) or without suspicion (n = 34) of tumor relapse. Although MRI was most effective in detecting local recurrencies (sensitivity: 100%), additional diagnostic information was only obtained in patients with mediastinal lesions. On the other hand, oncoscintigraphy was less sensitive (67%) but highly specific in differentiating reactive lymph node enlargement from metastatic disease (specificity: 93.5%). Oncoscintigraphy may be used instead of radioiodine scanning in patients with doubtful lymph node findings and spare them withdrawal of TSH-suppressive hormone medication. Routine estimation of serum thyroglobulin proved to be highly efficient in screening for tumor relapse using a cut-off level of 3 ng/ml (accuracy: 100%).

Adult↗
PubMed1994

F-18 fluorodeoxyglucose PET in vivo evaluation of pancreatic glucose metabolism for detection of pancreatic cancer.

PURPOSE: To evaluate positron emission tomography (PET) with fluorine-18-labeled fluorodeoxyglucose (FDG) for detection of pancreatic cancer compared with computed tomography (CT) and ultrasonography (US). MATERIALS AND METHODS: Forty patients with suspected pancreatic cancer underwent static PET after intravenous injection of 150-300 MBq FDG. Focal FDG accumulation was regarded as a sign of malignancy and was quantitated by calculating differential uptake ratios (DURs) and tumor-liver ratios (TLRs). RESULTS: Malignancy was histologically proved in 27 patients. PET helped correctly classify 25 of 27 malignant conditions and 11 of 13 benign disorders. DUR and TLR were statistically significantly higher in malignant compared with benign disease (P < .01). False-negative findings were obtained in patients with insulin-dependent diabetes. False-positive findings were noted in a patient with retroperitoneal fibrosis and in one with pancreas divisum with chronic pancreatitis. PET was superior to CT and US in detection of lymph node metastases (13 of 17 vs three of 17 or one of 15, respectively. CONCLUSION: FDG PET has the potential to improve the detection of lymphadenopathy and the differential diagnosis of pancreatic masses.

Adenocarcinoma↗
PubMed1993

[Intestinal motility after jejunum interposition and Roux-Y reconstruction--an animal experiment study].

An experimental study in animals was conducted to evaluate the motility patterns after total gastrectomy. Eight male beagle dogs (22.5-27.2 kg) had total gastrectomy with standardized designs of gastric substitution: (1) jejunal interposition (JI, n = 4); (2) Roux-en-Y reconstruction (RY, n = 4). Motility patterns were detected with perfused manometry (eight measuring ports), sequential scintigraphic emptying studies of the gastric substitute (caloric and acaloric medium viscosity test meals), and a hydrogen breath test with lactulose. The preoperative studies of the same individuals served as controls (CO). To detect postgastrectomy adaptation processes the postoperative studies were conducted 6-8, 12-14, and 24-30 weeks after total gastrectomy. The emptying of the gastric substitutes was markedly accelerated compared with CO after 6 months (T50: 5.8-8.1 min). In contrast to the preoperative studies, caloric test meals caused a trend to increase the velocity of the evacuation. The intestinal transit time was accelerated too in the weeks immediately, after the operation. In JI dogs intestinal transit was then markedly slowed and led to a highly significant difference after 6 months compared to RY animals (CO: 101 +/- 26min, JI: 104 +/- 18.2min, RY: 71.3 +/- 13.4min; p < 0.01). Pathologic motility patterns could be identified as the cause of this observations: RY dogs showed a marked increase of the intestinal motility index in the proximal jejunum (p < 0.0001) and a dissociation between the motility patterns of the duodenum and the gastric substitute. The observations gave rise for the supposition that this parts of the small bowel might generate two independent pacemarkers that both influence the lower intestinal parts after RY reconstruction. We conclude that the motility patterns of the entire small bowel highly influence the postoperative function of reconstruction procedures after total gastrectomy. The emptying velocity of the jejunal gastric substitute does not seem to have a major influence on the postoperative results. According to motility patterns jejunal interposition has a better outcome than Roux-en-Y reconstruction.

Anastomosis, Roux-en-Y↗
PubMed1993

[Radioimmunoscintimetry for intraoperative lymph node diagnosis in colorectal cancer].

In a prospective study 32 patients with primary colorectal carcinomas were studied by means of radioimmunoscintigraphy with the anti-carcinoembryonic antigen monoclonal antibody BW 431/26 labelled with either 131I (group 1, n = 17) or 99Tc (group 2, n = 15). Scintigraphy of the resected specimen was used as a model for intraoperative radioimmunoscintimetry, and all positive lymph nodes were marked during the investigation. The results were compared with the data yielded by preoperative investigations (CT, MR, endosonography) and checked by histology and immunohistochemistry. The analysis (sensitivity, specificity) included: type of investigation, time interval from antigen application, type of radionuclide, size of lymph nodes investigated, and serum level of CEA. 131I-Scintigraphy of the resected specimen gave the best results in the detection of lymph node metastases (sensitivity 1, specificity 0.57) and was superior to all other diagnostic procedures. When the investigation was performed 6-8 days after administration of the antibody the specificity improved to 1. The best results (sensitivity 1, specificity 0.91) were achieved in small (< 1 cm) lymph node metastases. A good correlation between scintigraphic diagnosis and immunohistochemical CEA detection was confirmed. Serum levels of CEA had no influence on the scintigraphic results. We conclude that intraoperative radioimmunodetection of lymph node metastases may improve the radicality in the resection of colorectal tumors. The best results are achieved with 131I-labelling and with application of the antibody 6-8 days before the operation.

Aged↗
PubMed1993

Pancreatic cancer detected by positron emission tomography with 18F-labelled deoxyglucose: method and first results.

In order to evaluate the utility of positron emission tomography (PET) with 18F-labelled deoxyglucose (FDG) for detection of pancreatic cancer 15 patients with pancreatic masses shown by computed tomography were investigated. Static PET scans covering an axial field of view of 15 cm were obtained 45 min after intravenous injection of 150-300 MBq FDG. Focally increased FDG accumulation was present in 12 out of 13 patients with histologically proven adenocarcinoma, in particular in eight of nine lymph node and four of five liver metastases. Scans of two patients with chronic pancreatitis confirmed by surgery revealed a normal FDG distribution. Contrast between tumour and normal tissue depended the metabolic situation prior to FDG injection. High ratios were found in fasting patients whereas no elevated FDG uptake was measured in an insulin-dependent diabetic suffering from carcinoma of the pancreatic head. We conclude that FDG PET might have the potential for detection and even differentiation of pancreatic carcinoma from chronic pancreatitis. Further studies are necessary to substantiate these preliminary findings and to optimize results in diabetic patients.

Adenocarcinoma↗
PubMed1993

[An incidental finding of a progressive diaphyseal dysplasia (Camurati-Engelmann syndrome)].

In a 35 year-old female diaphyseal hyperostosis of femur and tibia indicative of a Camurati-Engelmann syndrome (progressive diaphyseal dysplasia) were discovered during routine phlebography. This rare disorder belongs to the group of osteochondrodysplasias and affects primarily the diaphyses of long bones. Sporadic as well as familial cases have been observed. Although the cause and pathogenetic mechanism of the disease are unknown, an autosomal dominant inheritance is being discussed. Diagnosis was based on radiological findings, which are presented along with the scintigraphic appearance of the disease.

Adult↗
PubMed1993

Somatostatin receptor scintigraphy in malignant lymphoma: first results and comparison with glucose metabolism measured by positron-emission tomography.

Somatostatin receptor scintigraphy with 111In-labeled octreotide was performed in 22 patients with suspected or known malignant lymphoma. The majority of extra-abdominal lesions (21/24 = 87.5%) were correctly localized, however, only one of nine intraabdominal lymphomas could be detected. No significant correlation was found between scintigraphic results and histological type of lymphoma. Metabolic imaging by positron-emission tomography with 18F-labeled deoxyglucose yielded a higher rate of detection of lymphoma manifestations (92% vs 64%) and better tumor contrast. Further prospective studies are needed to establish the clinical relevance of somatostatin receptor scintigraphy in malignant lymphoma.

Adult↗
PubMed1993

[Type of stomach replacement and intestinal motility after total gastrectomy].

68 disease free patients were investigated prospectively after jejunal gastric replacement [jejunal interposition (JI): n = 40; Roux en Y reconstruction (RY): n = 28]. Used function tests were: scintigraphic emptying studies, hydrogen breath test, hepatobiliary sequential scintigraphy, oral glucose tolerance test, and upper intestinal manometry with 5 measuring ports (times of investigation: 6-12. week and > 1 year postoperatively). Patients with JI showed a better weight gain (p = 0.001), a lower reflux rate (p = 0.01), a slower orocecal transit time (p = 0.05), a prompter bile flow after meal stimulation (p = 0.02), and lower peak glucose levels (p = 0.001). The emptying patterns of the different gastric substitutes were not different. A higher incidence of retrograde contractions in RY and a electromechanical coordination between duodenum and gastric substitute in JI were detected. We conclude that the postoperative function of the jejunal gastric substitute does not depend on it's emptying pattern or volume but on the motility patterns of the entire intestinal tract which seem to be strongly influenced by the choice of the jejunal reconstruction.

Adenocarcinoma↗