See also H. T. Sørensen. Cancer and subsequent risk of venous thromboembolism. This issue, pp 527-8. Summary. Background: The incidence of venous thrombosis (VT) for cancer patients is increased compared with patients without cancer, but estimations of the incidence for different types of cancer have rarely been made because of the low incidence of various types of cancer. Large registries offer an opportunity to study the risk of VT in large cohorts of cancer patients, which is essential in decisions on prophylactic anti-coagulant treatment. Methods: This cohort study estimates the incidence of VT in cancer patients by using record linkage of a Cancer Registry and an Anticoagulation Clinic database in the Netherlands. Cumulative incidences in patients with different types of malignancies were estimated. We calculated relative risks (RRs) in relation to the presence of distant metastases and treatment. Results: Tumors of the bone, ovary, brain, and pancreas are associated with the highest incidence of VT (37.7, 32.6, 32.1, and 22.7/1000/0.5 year). Patients with distant metastases had a 1.9-fold increased risk [RR adj : 1.9; 95% confidence interval (CI): 1.6-2.3]. Chemotherapy leads to a 2.2-fold increased risk (RR adj : 2.2; 95% CI: 1.8-2.7) and hormonal therapy leads to a 1.6-fold increased risk (RR adj : 1.6; 95% CI: 1.3-2.1) compared with patients not using these treatment modalities. Patients with radiotherapy or surgery did not have an increased risk. Conclusions: We compared the overall incidences of VT in the first half year in our study to the risk of major bleeding as described in the literature. For patients with distant metastases, for several types of cancer, prophylactic anti-thrombotic treatment could be beneficial.

No abstract

No abstract

In this study, the possibilities for quantification of vessel diameters of peripheral arteries in gadolinium contrast-enhanced magnetic resonance angiography (Gd CE MRA) were evaluated. Absolute vessel diameter measurements were assessed objectively and semi-automatically in maximum intensity projections (MIPs) of contrast-enhanced T1-weighted 3D spoiled gradient-echo datasets, studied with digital subtraction techniques. In vivo, the complete peripheral arterial bed of six patients was studied, from the aorto-iliac bifurcation down to the distal run-off. By measuring the signal intensity (SI) over the lumen of a vessel in the MIP, an SI-plot was obtained. Next, the vessel boundaries were determined using a threshold algorithm; from these boundary points individual diameter values could be obtained along the trajectory of the vessel. In an in vitro study, an optimal threshold value of 30% of the range of SI-values between the background and the maximal SI in the vessel was obtained for accurate diameter measurement in Gd CE MRA (i.e., full-width 30%-maximum). Furthermore, the relationship between the accuracy of these measurements and the scan resolution was investigated. Accuracy was found to be acceptable (i.e., less than 10% over/underestimation) for vessel sizes covering at least 3 pixels. In six patients, diameters were measured in MIPs of the total datasets (i.e., D(T)) as well as in selective MIPs of the clipped datasets (i.e., D(S)) (n = 209). D(T) and D(S) were statistically significantly correlated (p < 0.01) with a Pearson correlation coefficient rP = 0.98. Measurements in the total MIPs yielded statistically significant (p < 0.01) smaller diameter values compared with measurements in selective MIPs, with a mean difference of 0.15 mm. Diameter values from the selective MIPs of the aorto-iliac arteries were also compared with diameter values measured at corresponding anatomic positions in X-ray angiograms of these patients (i.e., D(x)) (n = 70). D(X) and D(S) were statistically significantly correlated (p < 0.01) with a Pearson correlation coefficient rP = 0.92. Diameters measured in the selective MIPs were smaller than those measured in the X-ray angiograms (mean difference 0.49 mm) and this difference was statistically significant (p < 0.01). In conclusion, diameter values can be evaluated accurately in MIPs of vessels with at least 3 pixels in diameter, using the full-width 30%-maximum criterion.

No abstract

No abstract

We postulated that the distinct pathophysiologic mechanisms of airway narrowing during the early (EAR) and the late (LAR) asthmatic responses to inhaled allergens are reflected by the generation or transmission of lung sounds in asthma. Therefore, we measured FEV1 and recorded lung sounds in eight mildly asthmatic subjects before a standardized allergen challenge (PRE), during the EAR, during the recovery phase at 2 h (MID), during the LAR at 7 h, and after inhalation of a bronchodilator (POST). The recordings were made during flow- and volume-standardized quiet breathing, and during maximal forced breathing maneuvers. Airflow-dependent power spectra were analyzed for lung sound intensity (LSI), quartile power points (Q25, Q50, Q75), and extent of wheezing (W). These sound characteristics were compared among the various stages of the challenge in the presence (EAR, LAR) and absence (PRE, MID, POST) of acute airway obstruction using ANOVA. LSI, Q25 - Q75, and W were all elevated during airway obstruction. When matched for percent fall in FEV1, during the EAR and the LAR (mean +/- SD: 26.7 +/- 4.0, and 28.9 +/- 5.7, respectively; p = 0.385), the increase in Q25, and Q50 with airflow during quiet expiration, as well as the extent of wheezing, were higher during the LAR than during the EAR (p < or = 0.042 and p < or = 0.012, respectively). At similar levels of FEV1 (p > or = 0.156), LSI on expiration was higher at POST than at PRE or MID (p < or = 0.067), whereas Q25 (p < or = 0.047) and Q50 (p < or = 0.064) were lower at POST than at PRE. During forced expiration W was higher at MID and POST than at PRE (p < or = 0.014). We conclude that LSI, frequency content, and the extent of wheezing vary during the subsequent stages of allergen-induced bronchoconstriction in asthma despite matched values of FEV1. This suggests that airflow-standardized phonopneumography is a sensitive method for detecting differences in the pathophysiology of airway narrowing in asthma.

No abstract