[What investigations should be done following the first episode of pulmonary embolism?].

International audienceThromboembolic venous disease is both common and potentially serious, thus the first episode of pulmonary embolus calls for careful assessment. This involves two stages: a search for a venous localization of the pulmonary embolus and a search for risk factors contributing to thromboembolic venous disease. The emergence of non-invasive echographic-Doppler techniques and echocardiography make possible the localization of any residual venous thrombus. The risk of post thrombotic disease is raised in symptomatic thrombotic venous disease which requires wearing elastic stockings for a least two years. On the other hand this risk has not been assessed in asymptomatic cases of venous thrombosis. A search for risk factors requires a detailed history, a rigorous clinical examination and a routine list of laboratory investigations. Some complex investigations for detecting the early stages of a neoplasm would not appear justified unless there is objective evidence to support his. At the same time thrombophilia studies are not currently performed routinely for a first episode but may be suggested in the following cases: family history of thromboembolic venous disease, age less than 45, including those in whom the episode occurs at the same time as pregnancy, or whilst taking hormone therapy, idiopathic thromboembolism, the association of arterial and venous thrombi and finally venous thromboses occurring in an unusual anatomical site. Prospective studies have shown the value of long term anticoagulation in patients suffering from constitutional hemostatic anomalies. Finally, if there is an after thought of occult cancer or constitutional thrombocytopenia a careful follow up should be performed particularly during the first year

[What investigations should be done following the first episode of pulmonary embolism?].

International audienceThromboembolic venous disease is both common and potentially serious, thus the first episode of pulmonary embolus calls for careful assessment. This involves two stages: a search for a venous localization of the pulmonary embolus and a search for risk factors contributing to thromboembolic venous disease. The emergence of non-invasive echographic-Doppler techniques and echocardiography make possible the localization of any residual venous thrombus. The risk of post thrombotic disease is raised in symptomatic thrombotic venous disease which requires wearing elastic stockings for a least two years. On the other hand this risk has not been assessed in asymptomatic cases of venous thrombosis. A search for risk factors requires a detailed history, a rigorous clinical examination and a routine list of laboratory investigations. Some complex investigations for detecting the early stages of a neoplasm would not appear justified unless there is objective evidence to support his. At the same time thrombophilia studies are not currently performed routinely for a first episode but may be suggested in the following cases: family history of thromboembolic venous disease, age less than 45, including those in whom the episode occurs at the same time as pregnancy, or whilst taking hormone therapy, idiopathic thromboembolism, the association of arterial and venous thrombi and finally venous thromboses occurring in an unusual anatomical site. Prospective studies have shown the value of long term anticoagulation in patients suffering from constitutional hemostatic anomalies. Finally, if there is an after thought of occult cancer or constitutional thrombocytopenia a careful follow up should be performed particularly during the first year

Computer assisted venous thrombosis quantification

International audienceVenous thrombosis (VT) volume assessment, by verifying its risk of progression when anticoagulant or thrombolytic therapies are prescribed, is often necessary to screen life- threatening complications. Commonly, VT volume estimation is done by manual delineation of few contours in the ultrasound (US) image sequence, assuming that the VT has a regular shape and constant radius, thus producing significant errors. This paper presents and evaluates a comprehensive functional approach based on the combination of robust anisotropic diffusion and deformable contours to calculate VT volume in a more accurate manner when applied to freehand 2-D US image sequences. Robust anisotropic filtering reduces image speckle noise without generating incoherent edge discontinuities. Prior knowledge of the VT shape allows initializing the deformable contour, which is then guided by the noise-filtering outcome. Segmented contours are subsequently used to calculate VT volume. The proposed approach is integrated into a system prototype compatible with existing clinical US machines that additionally tracks the acquired images 3-D position and provides a dense Delaunay triangulation required for volume calculation. A predefined robust anisotropic diffusion and deformable contour parameter set enhances the system usability. Experimental results pertinence is assessed by comparison with manual and tetrahedron-based volume computations, using images acquired by two medical experts of eight plastic phantoms and eight in vitro VTs, whose independently measured volume is the reference ground truth. Results show a mean difference between 16 and 35 mm3 for volumes that vary from 655 to 2826 mm3. Two in vivo VT volumes are also calculated to illustrate how this approach could be applied in clinical conditions when the real value is unknown. Comparative results for the two experts differ from 1.2% to 10.08% of the smallest estimated value when the image acquisition cadences are similar

Comparative Neural Network Based Venous Thrombosis Echogenicity and Echostructure Characterization Using Ultrasound Images

International audienceVenous thrombosis is a common pathology that creates serious public health problems. Thrombosis diagnosis, particularly the determination of their echogenicity and echostructure can be efficiently accomplished by a medical expert using ultrasound imaging. On the other hand, the predictive capability of artificial neural networks is very useful in medical applications and can support medical experts to take appropriate diagnosis decisions. Therefore, the proposed study intends to characterize by means of neural networks the thrombosis echogenicity and echostructure, using a predefined learning base that depends on the prior knowledge of physicians. We have studied six different methods to characterize the thrombosis images, along with the six corresponding neural networks. Obtained results show that the optimal feature vector size, the simplest neural network architecture, and the smallest error, are achieved by using the mean-variance approach or by the wavelet coefficients energies metho

Détection des Contours des Thrombus Veineux dans les Images Echographiques

International audienceDétection des Contours des Thrombus Veineux dans les Images Echographique

Volume calculation of venous thrombosis using 2D ultrasound images

International audienceVenous thrombosis screening exams use 2D ultrasound images, from which medical experts obtain a rough idea of the thrombosis aspect and infer an approximate volume. Such estimation is essential to follow up the thrombosis evolution. This paper proposes a method to calculate venous thrombosis volume from non-parallel 2D ultrasound images, taking advantage of a priori knowledge about the thrombosis shape. An interactive ellipse fitting contour segmentation extracts the 2D thrombosis contours. Then, a Delaunay triangulation is applied to the set of 2D segmented contours positioned in 3D, and the area that each contour defines, to obtain a global thrombosis 3D surface reconstruction, with a dense triangulation inside the contours. Volume is calculated from the obtained surface and contours triangulation, using a maximum unit normal component approach. Preliminary results obtained on 3 plastic phantoms and 3 in vitro venous thromboses, as well as one in vivo case are presented and discussed. An error rate of volume estimation inferior to 4,5% for the plastic phantoms, and 3,5% for the in vitro venous thromboses was obtained

Bilateral thenar hammer syndrome.

International audienceThenar hammer syndrome is a very rare condition that mimics rheumatic diseases such as carpal syndrome tunnel, Raynaud's phenomenon, and hand synovitis. To describe the sonographic presentation of thenar hammer syndrome in a typical patient. Grey-scale sonography and colour Doppler imaging of the hands with an iU22 scanner (Philips) were performed. In B mode, the lesion was seen as a large, rounded, heterogeneous area combining hypoechoic and echogenic components. Pseudoaneurysm was diagnosed based on presence of a cystic saccular formation arising directly from the adjacent artery and exhibiting an irregular thick wall with turbulent blood flow in the lumen. Colour Doppler showed blood flow in part of the lumen, the rest of which was filled with a thrombus seen as echogenic tissue. Sonography can help to diagnose thenar hammer syndrome. Angiography may be unnecessary in patients with normal colour Doppler findings

High prevalence of asymptomatic deep vein thrombosis on admission in a medical unit among elderly patients.

International audienceThe prevention of venous thromboembolism in medical patients remains questioned. All consecutive outpatients admitted in our medical unit were considered for inclusion in this study which aimed to estimate the prevalence of asymptomatic venous thrombosis on admission and the incidence during hospital stay. Exclusion criteria were: age <18 years, suspicion of venous thromboembolism, stay <4 days, ongoing anticoagulant therapy. Venous compression ultrasonography of the lower limbs was performed within 48 h. 234 patients were included. The prevalence of asymptomatic deep vein thrombosis on admission and the incidence during hospital follow-up were respectively 5.5% (95% confidence interval, 3.1 to 9.5%) and 2.6 per 1,000 person-days (95% confidence interval, 0.0 to 5.2). The prevalence and the incidence reached respectively 17.8% (95% confidence interval, 8.5 to 32.6%) and 6.0 per 1,000 person-days (95% confidence interval, 0.0 to 12.7) among patients over 80 years. A high prevalence of asymptomatic deep vein thrombosis on admission was suggested particularly among elderly medical patients

[Calf muscle venous thrombosis and pulmonary embolism].

International audienceINTRODUCTION: The clinical significance of calf muscle venous thrombosis (CMVT) still remains a matter of debate. Detected by ultrasonography, they are overlooked by venography. This prompted us to evaluate the frequency of such localizations and their association to pulmonary embolism (PE). METHODS: Retrospective review of our database over a three-year period. All patients with an isolated CMVT were included. RESULTS: Isolated CMVT were detected in 106 patients (mean age 68.6 years; 65% women), that is 12.5% of all venous thromboses diagnosed in the vascular sonography unit over the study period Sixteen associated PE were detected (15%). CONCLUSIONS: Association of CMVT and PE is not infrequent. Whether or not such thromboses have the potential to extend into deep veins and/or to migrate into pulmonary circulation requires further studies