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W J G Oyen

Publications and source records attributed to W J G Oyen.

At least 19 recordsLinked to original sources
PubMed2007

Complicating infectious foci in patients with Staphylococcus aureus or Streptococcus species bacteraemia.

Complicating infectious foci resulting from haematogenous or local spread of microorganisms are observed frequently in patients with Staphylococcus aureus bacteraemia (SAB) or Streptococcus species bacteraemia (SSB). The aim of this study was to compare the epidemiology of complicating infectious foci during SAB and SSB in a university hospital in The Netherlands. The charts of all adult patients diagnosed with SAB or SSB (except for Streptococcus pneumoniae bacteraemia) from July 2002 until December 2004 were reviewed retrospectively. Overall, 180 immunocompetent patients were identified, 127 with SAB and 53 with SSB. The percentage of patients with complicating infectious foci (39% of SAB patients, 25% of SSB patients) did not differ significantly between the groups. Endocarditis and cerebral involvement, however, were significantly more common in the SSB group. Of all complicating infectious foci, 32% lacked guiding signs or symptoms and 10% were detected only at autopsy. Factors associated with the development of complicating infectious foci were a delay in treatment for more than 48 h after the onset of symptoms, community acquisition, persistently positive blood cultures, congenital heart disease, and the presence of foreign bodies or prosthetic valves. Infection-related mortality was 18% in SAB patients and 11% in SSB patients and was significantly higher in patients with complicating infectious foci (29 vs. 9%). In conclusion, complicating infectious foci develop in approximately one-third of all patients with SAB and SSB. An active approach that entails searching for the complicating infectious foci is warranted in these patients, because only two-thirds of complicated infectious foci have guiding symptoms or signs, and infection-related mortality is significantly increased in patients with complicating infectious foci compared to patients without these infections.

Bacteremia↗
PubMed2007

The role of FDG-PET in the selection of patients with colorectal liver metastases.

BACKGROUND: Selection of patients for hepatic resection of colorectal liver metastases is still limited. After conventional work up by computed tomography (CT) scan, 60% of patients will develop recurrent disease in the early years after resection. The aim of the present study was to evaluate whether an additional fluorine-18-deoxyglucose positron emission tomography (FDG-PET) improves patient selection and therefore adds value to select patients for curative liver resection. METHODS: Data from 203 patients selected for surgical treatment of colorectal liver metastases between 1995 and 2003 were collected in a prospective database. Group A consisted of 100 consecutive patients selected for hepatic surgery by conventional diagnostic imaging (CT chest and abdomen) only. Group B consisted of 103 consecutive patients selected for hepatic surgery by conventional diagnostic methods plus an additional FDG-PET. RESULTS: The number of patients with futile surgery, in which further treatment was considered inappropriate at laparotomy, was 28.0% in group A and 19.4% in group B. The reason for unresectable disease differed between groups. In group A, 10/100 (10.0%) patients showed extrahepatic abdominal disease versus 2/103 patients (1.9%) in group B (P = .017). In all other cases, resection was not performed because liver disease proved too extensive at laparotomy. For patients ultimately undergoing surgical treatment of the metastases, survival was comparable between groups. Overall survival at 3 years was 57.1% in group A versus 60.1% in group B. Disease-free survival at 3 years was 23.0% in group A and 31.4% in group B. CONCLUSIONS: In patients with colorectal liver metastases, FDG-PET may reduce the number of negative laparotomies. However, the effect size on the selection of these patients seems not sufficient enough to affect the overall and disease-free survival after treatment.

Adult↗
PubMed2006

Comparison of multiphase CT, FDG-PET and intra-operative ultrasound in patients with colorectal liver metastases selected for surgery.

BACKGROUND: For patients with colorectal liver metastases, resection is the treatment of choice. Careful selection of these patients is crucial in order to reduce the chance of unexpected findings at laparotomy and abandoning further surgical intervention. Here, we evaluate the predictive value of CT and FDG-PET of the liver and extrahepatic findings compared to findings during laparotomy and 6 months follow-up. METHODS: 131 consecutive patients, selected for hepatic surgery for colorectal liver metastases by CT and FDG-PET, were evaluated prospectively. During surgery, the liver was assessed by intra-operative ultrasound, palpation and histology. RESULTS: In 127 patients (97%), CT was true-positive for liver metastases. In 3 patients, CT was false-positive and in 1 patient false-negative. In 126 patients (96%), FDG-PET was true-positive for liver metastases, in 2 patients FDG-PET was false-negative, in 3 patients true-negative (negative FDG-PET, false-positive CT). At laparotomy a total of 363 liver metastases was identified: 63 lesions <10 mm [10 (16%) detected by both CT and FDG-PET], 172 lesions of 10-20 mm [123 (72%) CT-positive, 129 (75%) by FDG-PET-positive], and 28 lesions >20 mm [124 (97%) CT-positive, 121 (95%) FDG-PET-positive]. CT and FDG-PET missed approximately 30% of the smaller liver lesions, resulting in a significant change in clinical management during surgery in only nine patients. CONCLUSIONS: CT and FDG-PET have a similar diagnostic yield for the identification of liver metastases; both modalities being adequate on a patient-basis but inadequate to detect the smallest of liver lesions. However, the clinical relevance of the latter is limited.

Adult↗
PubMed2006

From anatomical to biological target volumes: the role of PET in radiation treatment planning.

Progress in radiation oncology requires a re-evaluation of the methods of target volume delineation beyond anatomical localization. New molecular imaging techniques for tumour visualisation such as positron emission tomography (PET) provide insight into tumour characteristics and can be complementary to the anatomical data of computed tomography or magnetic resonance imaging. In this review, three issues are discussed: First, can PET identify a tumour more accurately? Second, can biological tumour characteristics be visualised? Third, can intratumoural heterogeneity of these characteristics be identified?

Cell Hypoxia↗
PubMed2006

Diagnostic value of asymmetric striatal D2 receptor upregulation in Parkinson's disease: an [123I]IBZM and [123I]FP-CIT SPECT study.

INTRODUCTION: Striatal postsynaptic D2 receptors in Parkinson's disease (PD) are thought to be upregulated in the first years of the disease, especially contralateral to the clinically most affected side. The aim of this study was to evaluate whether the highest striatal D2 binding is found contralateral to the most affected side in PD, and whether this upregulation can be used as a diagnostic tool. METHODS: Cross-sectional survey was undertaken of 81 patients with clinically asymmetric PD, without antiparkinsonian drugs and with a disease duration of < or = 5 years and 26 age-matched controls. Striatal D2 binding was assessed with [123I]IBZM SPECT, and severity of the presynaptic dopaminergic lesion with [123I]FP-CIT SPECT. RESULTS: The mean striato-occipital ratio of [123I]IBZM binding was significantly higher in PD patients (1.56 +/-0.09) than in controls (1.53 +/-0.06). In PD patients, higher values were found contralateral to the clinically most affected side (1.57 +/-0.09 vs 1.55 +/-0.10 ipsilaterally), suggesting D2 receptor upregulation, and the reverse was seen using [123I]FP-CIT SPECT. However, on an individual basis only 56% of PD patients showed this upregulation. CONCLUSION: Our study confirms asymmetric D2 receptor upregulation in PD. However, the sensitivity of contralateral higher striatal [123I]IBZM binding is only 56%. Therefore, the presence of contralateral higher striatal IBZM binding has insufficient diagnostic accuracy for PD, and PD cannot be excluded in patients with parkinsonism and no contralateral upregulation of D2 receptors, assessed with [123I]IBZM SPECT.

Benzamides↗
PubMed2006

FDG-PET for prediction of survival of patients with metastatic colorectal carcinoma.

BACKGROUND: The current study focuses on the prognostic value of pretreatment metabolic activity in metastases as measured with [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET), as an indicator of survival in colorectal cancer. PATIENTS AND METHODS: In a prospective series of 152 patients with metastatic colorectal cancer, of whom 67 were treated with resection of metastases and 85 with chemotherapy, standardized uptake values (SUV) as measured with FDG-PET, were calculated prior to treatment. Survival probabilities were estimated by Cox proportional regression analysis. For Kaplan-Meier analysis SUV was stratified by the median value. Survival differences were assessed using the log-rank test. RESULTS: SUV in metastases was a significant predictor for overall survival (hazard ratio 1.17, 95% confidence interval 1.06-1.30, P = 0.002), independent of the subsequent treatment. According to the median value of the patient population a low (SUV <4.26) and high uptake group (SUV >4.26) was defined. The median survival and the 2- and 3-year survival rates were 32 months, 59% and 45%, respectively, in the low-uptake group and 19 months, 37% and 28%, respectively, in the high-uptake group (P = 0.017). CONCLUSION: A significant survival benefit was observed in patients with low FDG uptake in metastases of colorectal cancer.

Adult↗
PubMed2006

Impact of [18F]fluorodeoxyglucose positron emission tomography on surgical management of melanoma patients.

BACKGROUND: Several studies have shown adequate sensitivity and specificity of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) for the detection of metastases from melanoma, but few have addressed its impact on treatment. The aim of this retrospective study was to assess the impact of FDG-PET on treatment of melanoma in three Dutch university medical centres. METHODS: The medical records of 257 patients were reviewed. The indications for FDG-PET and findings were recorded. Unexpected findings of suspected (pre)malignant tumours other than melanoma were assessed. Treatment plans before and after FDG-PET were recorded and analysed to evaluate changes in disease management. RESULTS: Most scans (71.2 per cent) were requested for staging, mainly to detect distant metastases in patients with stage III disease. Overall, 56 patients (21.8 per cent) were upstaged as a result of PET. In 44 patients (17.1 per cent) treatment was changed, usually from surgery to systemic treatment in patients with stage III disease. Unexpected tumours were detected (mainly colorectal) in 11 patients (4.3 per cent). CONCLUSION: FDG-PET is most valuable in patients with stage III melanoma for detection of distant metastases and identification of candidates for surgery and/or systemic treatment. Unexpected FDG-PET findings should not be disregarded, as (pre)malignant, clinically relevant, tumours may be identified.

Adolescent↗
PubMed2006

FDG-PET for imaging of non-osseous infection and inflammation.

UNLABELLED: FDG-PET is emerging as a promising imaging technique in non-osseous infectious and inflammatory diseases, as an increasing number of reports are appearing in literature. In general, sensitivity of FDG-PET in diagnosing non-osseous infections compares favorably to other diagnostic modalities. Lower specificity due to FDG accumulation in conditions involving leukocyte activation and malignancy may be overcome by implementing FDG-PET in a diagnostic protocol. In fever of unknown origin, FDG-PET appears to be of great advantage as malignancy, inflammation and infection can be detected. Studies on standardized uptake value ratios, uptake patterns and dynamics may be helpful to increase specificity. Image fusion combining PET and CT facilitates anatomical localization of increased FDG-uptake and better guiding for further diagnostic tests to achieve a final diagnosis. More data on the utility of FDG-PET to monitor the response to treatment will be available in near future. Early reports on FDG-PET during treatment follow-up in large vessel vasculitis already showed promising RESULTS: In conclusion, the body of evidence on the utility of FDG-PET in non-osseous infection and inflammation is growing and FDG-PET may become one of the preferred diagnostic procedures for these diseases.

Clinical Trials as Topic↗
PubMed2006

What is the best pre-therapeutic dosimetry for successful radioiodine therapy of multifocal autonomy?

PURPOSE: Dose calculation for radioiodine therapy (RIT) of multifocal autonomies (MFA) is a problem as therapeutic outcome may be worse than in other kinds of autonomies. We compared different dosimetric concepts in our patients. PATIENTS, METHODS: Data from 187 patients who had undergone RIT for MFA (Marinelli algorithm, volumetric compromise) were included in the study. For calculation, either a standard or a measured half-life had been used and the dosimetric compromise (150 Gy, total thyroid volume). Therapeutic activities were calculated by 2 alternative concepts and compared to therapeutic success achieved (concept of TcTUs-based calculation of autonomous volume with 300 Gy and TcTUs-based adaptation of target dose on total thyroid volume). RESULTS: If a standard half-life is used, therapeutic success was achieved in 90.2% (hypothyroidism 23,1%, n = 143). If a measured half-life was used the success rate was 93.1% (13,6% hypothyroidism, n = 44). These differences were statistically not significant, neither for all patients together nor for subgroups eu-, hypo-, or hyperthyroid after therapy (ANOVA, all p > 0.05). The alternative dosimetric concepts would have resulted either in significantly lower organ doses (TcTUs-based calculation of autonomous volume; 80.76 +/- 80.6 Gy versus 125.6 +/- 46.3 Gy; p < 0.0001) or in systematic over-treatment with significantly higher doses (TcTUs-adapted concept; 164.2 +/- 101.7 Gy versus 125.6 +/- 46.3 Gy; p = 0.0097). CONCLUSIONS: TcTUsbased determination of the autonomous volume should not be performed, the TcTUs-based adaptation of the target dose will only increase the rate of hypothyroidism. A standard half-life may be used in pre-therapeutic dosimetry for RIT of MFA. If so, individual therapeutic activities may be calculated based on thyroid size corrected to the 24h ITUs without using Marinelli's algorithm.

Dose-Response Relationship, Radiation↗
PubMed2005

Radioimmunotherapy and colorectal cancer.

BACKGROUND: Despite the success of radioimmunotherapy (RIT) using radiolabelled monoclonal antibodies (Mabs) directed against tumour-associated antigens in the treatment of non-Hodgkin's lymphoma, therapeutic success in solid tumours has been modest. In the past decade, a dozen Mabs have been investigated clinically for their potential usefulness in RIT of colorectal cancer. METHODS: The application of radiolabelled Mabs for the treatment of solid cancers is discussed, and clinical trials investigating RIT for colorectal cancer listed in the Medline and Embase databases are reviewed. RESULTS: Uptake of radiolabelled Mabs in tumour and, consequently, the therapeutic efficacy of RIT is inversely correlated with tumour size. The bone marrow is the most important dose-limiting organ. Twenty-three phase I/II studies were found that investigated the feasibility and efficacy of RIT using five radionuclides and 15 Mabs against carcinoembryonic antigen, tumour-associated glycoprotein 72, epithelial cellular adhesion molecule, A33 or colon-specific antigen p, mainly in patients with advanced colorectal cancer. A few responses were recorded but no particular antibody construct seemed superior. CONCLUSION: RIT might be an effective adjuvant treatment modality in colorectal cancer. Future studies should focus on its application in patients with small-volume or minimal residual disease.

Antibodies, Monoclonal↗
PubMed2005

Value of fluorodeoxyglucose positron emission tomography in women with breast cancer.

BACKGROUND: The aim of this prospective study was to evaluate the role of fluorodeoxyglucose positron emission tomography (FDG-PET) in the staging of high-risk women with primary or recurrent breast cancer. METHODS: FDG-PET was performed in 42 women with a primary breast cancer and unfavourable characteristics, or who had a suspected relapse. FDG-PET and conventional staging methods were compared. In case of abnormality on FDG-PET, confirmation was always attempted. RESULTS: Increased uptake was found in five of 17 women with a primary cancer. In the 25 women with a suspected relapse, FDG-PET showed increased uptake in 43 areas, 22 correctly confirming the area of suspected relapse and 21 indicating other sites of metastases. Compared with conventional imaging, FDG-PET revealed additional (confirmed) lesions in two women with primary cancers and three with relapse. Patient management was changed for five women. CONCLUSION: FDG-PET is a sensitive diagnostic method for the detection of distant metastatic disease. Its exact role in women with breast cancer remains to be defined.

Adult↗
PubMed2005

Aortitis diagnosed by F-18-fluorodeoxyglucose positron emission tomography in a patient with syphilis and HIV coinfection.

The most common manifestation of cardiovascular syphilis, a rare diagnosis since the introduction of penicillin, is aortitis of the ascending aorta. Since the majority of patients with uncomplicated aortitis are asymptomatic, early diagnosis is difficult. We report the case of an HIV-positive patient with asymptomatic syphilitic aortitis that was incidentally diagnosed with F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET). We conclude that FDG-PET could become a promising new imaging technique for both diagnosis and follow-up of patients with syphilitic aortitis.

Adult↗
PubMed2005

Diagnosis of Candida lung abscesses by 18F-fluorodeoxyglucose positron emission tomography.

In three patients with catheter-associated candidaemia, use of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) led to the diagnosis of Candida lung abscesses, which was confirmed by computed tomography and a favourable response to antifungal therapy. It was concluded that FDG-PET is a promising new imaging technique that enables early identification of sites of disseminated candidiasis, and that this technique can be used in the evaluation of therapy.

Adult↗
PubMed2004

Accuracy of rigid CT-FDG-PET image registration of the liver.

Diagnostic and surgical strategies could benefit from accurate localization of liver malignancies via CT-FDG-PET image registration. However, registration uncertainty occurs due to protocol differences in data-acquisition, the limited spatial resolution of positron emission tomography (PET) and the low uptake of 18F-fluorodeoxyglucose (FDG) in normal liver tissue. To assess this uncertainty, methods were presented to estimate registration precision and systematic bias. A semi-automatic, organ-focused method was investigated to minimize the uncertainty well beyond the typical uncertainty of 5-10 mm obtained by commonly available methods. By restricting registration to the liver region and by isolating the liver on computed tomography (CT) from surrounding structures using a thresholding technique, registration was achieved using the mutual information-based method as implemented in insight toolkit (ITK). CT and FDG-PET images of 10 patients with liver metastases were registered rigidly a number of times. Results of the organ-focused method were compared to results of three commonly available methods (a manual, a landmark-based and a 'standard' mutual information-based method) where no dedicated image processing was performed. The proposed method outperformed the other methods with a precision (mean+/-s.d.) of 2.5+/-1.3 mm and a bias of 1.9 mm with a 95% CI of [1.0, 2.8] mm. Unlike the commonly available methods, our approach allows for robust CT-FDG-PET registration of the liver, with an accuracy better than the spatial resolution of the PET scanner that was used.

Fluorodeoxyglucose F18↗
PubMed2004

FDG-PET in staging lung cancer: how does it change the algorithm?

BACKGROUND: In patients with lung cancer, positron emission tomography (PET) using fluor-18-fluorodesoxyglucose (FDG) may be used both to detect extrathoracic metastases (ETM) and for mediastinal lymph node staging (MLS), potentially reducing the need for mediastinoscopy. We assessed the added value of FDG-PET in detecting ETM and focused on the reliability of FDG-PET and mediastinoscopy for MLS. PATIENTS AND METHODS: In 72 consecutive patients with non-small cell lung cancer, the impact of adding FDG-PET to full conventional clinical staging was prospectively analyzed. The predictive value of FDG-PET findings and tumor location for pathologic mediastinal lymph node status were assessed in a logistic regression analysis. RESULTS: Unexpected extrathoracic metastases were detected by FDG-PET in 15% of patients. In MLS overall negative and positive predictive values were 71 and 83% for FDG-PET, and 92 and 100% for mediastinoscopy. However, the negative predictive value of FDG-PET was only 17% in case of FDG-PET positive N1 nodes and/or a centrally located primary tumor, whereas it was 96% in case of FDG-PET negative N1 nodes and a non-centrally located primary tumor. CONCLUSION: By incorporating FDG-PET in clinical staging, 15% of patients with lung cancer are upstaged due to unexpected extrathoracic metastases. In case of a negative mediastinal FDG-PET, mediastinoscopy can only be omitted in the presence of a non-centrally located primary tumor and without FDG-PET positive N1 nodes.

Adolescent↗
PubMed2004

Solitary skull recurrence from stage I seminomatous germ cell tumor of testis.

We describe a 35-year-old man who was initially treated with standard inguinal orchiectomy and prophylactic radiotherapy for Stage I seminomatous germ cell tumor of the testis. We report the case because of the unique nature of the later disease recurrence, which was a solitary cranial bony recurrence that extended both intracranially and extracranially. The patient had complete remission after combined cisplatin-based chemotherapy.

Adult↗
PubMed2004

F-18-fluorodeoxyglucose positron emission tomography leading to a diagnosis of septic thrombophlebitis of the portal vein: description of a case history and review of the literature.

Pylephlebitis or septic thrombophlebitis of the portal vein is a serious infectious disorder. Early diagnosis is difficult, due to nonspecific symptoms and signs, limitations of diagnostic modalities and the lack of familiarity of physicians with this entity. We report the history of a 73-year-old man with fever of unknown origin (FUO) in whom laboratory tests, blood and urine cultures, chest X-ray, abdominal ultrasound, and Indium-111-leucocyte scintigraphy did not reveal the cause of the fever. F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) subsequently pointed to the diagnosis of pylephlebitis, which was confirmed by computed tomography (CT) and percutaneous puncture. We conclude that FDG PET allows detecting inflammatory foci in patients with FUO and offers to make the diagnosis of pylephlebitis at an early stage.

Aged↗