Duplex Ultrasound Scanning is Reliable in the Detection of Endoleak Following Endovascular Aneurysm Repair

Department of Cardiovascular Sciences, University of Leicester, Leiscester, England, United Kingdom
European Journal of Vascular and Endovascular Surgery (Impact Factor: 2.49). 12/2006; 32(5):537-41. DOI: 10.1016/j.ejvs.2006.05.013
Source: PubMed


To investigate the value of duplex ultrasound scanning (DUSS) in the routine follow up of patients following EVAR.
Imaging was reviewed for 310 consecutive patients undergoing EVAR at a single centre. Concurrent ultrasound and CT scans were defined as having occurred within 6 months of each other. There were 244 paired concurrent DUSS and CT scans which were used for further analysis. These modalities were compared with respect to sensitivity, specificity, positive and negative predictive values and level of agreement (by Kappa statistics) using CT as the 'gold standard'.
DUSS failed to detect a number of endoleaks which were seen on CT and the sensitivity of this test was therefore poor (67%). However, the specificity of DUSS compared more favourably with a value of 91%. Positive predictive values ranged from 33-100% but negative predictive values were more reliable with values of 91-100% at all time points post operatively. There were no type I leaks, or endoleaks requiring intervention which were missed on DUSS. Overall, there was a 'fair' level of agreement between the two imaging modalities using Kappa statistics.
Although DUSS is not as sensitive as CT scanning in the detection of endoleak, no leaks requiring intervention were missed on DUSS in this study. DUSS is much cheaper than CT and avoids high doses of radiation. DUSS therefore remains a valuable method of follow up after EVAR and can reduce the need for repeated CT scans.

Download full-text


Available from: Nicholas Guy Fishwick, Apr 17, 2014
32 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: The harderian gland is an orbital gland of the majority of land vertebrates. It is the only orbital gland in anuran amphibians since the lacrimal gland develops later during phylogenesis in some reptilian species. Perhaps because it is not found in man, little interest was paid to this gland until about four decades ago. In recent years, however, the scientific community has shown new interest in analyzing the ontogenetic and morphofunctional aspects of the harderian gland, particularly in rodents, which are the preferred experimental model for physiologists and pathologists. One of the main characteristics of the gland is the extreme variety not only in its morphology, but also in its biochemical properties. This most likely reflects the versatility of functions related to different adaptations of the species considered. The complexity of the harderian gland is further shown in its control by many exogenous and endogenous factors, which vary from species to species. The information gained so far points to the following functions for the gland: (1) lubrication of the eye and nictitating membrane, (2) a site of immune response, particularly in birds, (3) a source of pheromones, (4) a source of saliva in some chelonians, (5) osmoregulation in some reptiles, (6) photoreception in rodents, (7) thermoregulation in some rodents, and (8) a source of growth factors.
    International Review of Cytology 02/1996; 168:1-80. DOI:10.1016/S0074-7696(08)60882-7 · 9.00 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents a new approach based on the differential framework proposed by Horn and Schunck, to the problem of recursive optical flow estimation from image sequences. The original method of Horn and Schunck is applicable only to the problem of estimating the optical flow between a pair of images from an image sequence. When we aim at estimating the optical flow for long image sequences recursively, the question is whether and how can we gain from previous estimates. In this paper we show that gain is achieved from both computational and accuracy points of view. Incorporation of the time axis into the estimation process is done by assuming temporal smoothness of the optical flow, resulting in simplified spatial–temporal models. The obtained models permit incorporation of the constrained weighted least squares (CWLS) estimator. This estimator is shown to yield RLS and LMS adaptive filter versions for recursive optical flow estimation in time. An interesting and desirable property of the proposed estimation algorithms is their flexibility with respect to performance versus computational requirements. By a simple choice of a parameter these algorithms can be modified to exploit the available time to improve their performance with respect to estimation error. The convergence properties of these estimation algorithms are analyzed. Simulations for various image sequences support the analysis and demonstrate the performance of the estimation algorithms.
    Journal of Visual Communication and Image Representation 06/1998; 9(2-9):119-138. DOI:10.1006/jvci.1998.0382 · 1.22 Impact Factor
Show more