Outcomes of complex femorodistal sequential autologous vein and biologic prosthesis composite bypass grafts

ObjectiveFemorodistal autologous vein bypass proves to be the preferred surgical therapy for long arterial occlusions and provides excellent early and long-term results in critical lower limb ischemia. Whenever vein length was insufficient and two distal outflow arteries were present, a sequential composite bypass configuration was chosen with human umbilical vein (HUV) or ovine collagen prosthesis (Omniflow II; Bio Nova International Pty Ltd, North Melbourne, Australia) as the proximal prosthetic part of the bypass. Single-center experience with this technique regarding limb salvage, graft function, secondary reinterventions, and biodegeneration is presented.MethodsBetween January 1998 and January 2009, 122 consecutive sequential composite bypass operations were performed on 116 patients for short-distance claudication (2), chronic critical ischemia (117), or acute ischemia (3) in the absence of sufficient autologous vein length. HUV was used in 90 cases and Omniflow II in 32 cases. Grafts were followed by duplex scan supplemented by angiography in case of recurrent ischemia with prospective documentation of follow-up data in a computerized vascular database. Retrospective analysis of graft patency, limb salvage, and aneurysmal degeneration of the biologic prosthesis was performed.ResultsMean follow-up was 59 ± 45.5 months (range, 1-161 months). The 30-day mortality was 4.1%. Early postoperative complete or partial bypass thrombosis developed in 16% (20 cases) and required successful revision in 16 cases. During follow-up, 30 complete and 12 partial bypass occlusions occurred, necessitating selective surgical or interventional revision. Primary, primary assisted, and secondary patency rates and the limb salvage rate were 48%, 62%, 71%, and 87%, respectively, after 5 years and 26%, 46%, 54%, and 77%, respectively, after 10 years for all bypasses. Late biodegeneration of HUV prostheses was detected in four instances.ConclusionsLate graft patency and limb salvage were good. These factors, combined with a tolerable rate of late aneurysmal degeneration, justify the use of biologic vascular conduits and autologous vein for complex femorodistal reconstructions

Utility of knife-edge position tracking in cycloidal computed tomography

Cycloidal computed tomography provides high-resolution images within relatively short scan times by combining beam modulation with dedicated under-sampling. However, implementing the technique relies on accurate knowledge of the sample’s motion, particularly in the case of continuous scans, which is often unavailable due to hardware or software limitations. We have developed an easy-to-implement position tracking technique using a sharp edge, which can provide reliable information about the trajectory of the sample and thus improve the reconstruction process. Furthermore, this approach also enables the development of other innovative sampling schemes, which may otherwise be difficult to implement

X-ray phase-contrast microtomography of soft tissues using a compact laboratory system with two-directional sensitivity

X-ray microtomography is a nondestructive, three-dimensional inspection technique applied across a vast range of fields and disciplines, ranging from research to industrial, encompassing engineering, biology, and medical research. Phase-contrast imaging extends the domain of application of x-ray microtomography to classes of samples that exhibit weak attenuation, thus appearing with poor contrast in standard x-ray imaging. Notable examples are low-atomic-number materials, like carbon-fiber composites, soft matter, and biological soft tissues. We report on a compact and cost-effective system for x-ray phase-contrast microtomography. The system features high sensitivity to phase gradients and high resolution, requires a low-power sealed x-ray tube, a single optical element, and fits in a small footprint. It is compatible with standard x-ray detector technologies: in our experiments, we have observed that single-photon counting offered higher angular sensitivity, whereas flat panels provided a larger field of view. The system is benchmarked against known-material phantoms, and its potential for soft-tissue three-dimensional imaging is demonstrated on small-animal organs: a piglet esophagus and a rat heart. We believe that the simplicity of the setup we are proposing, combined with its robustness and sensitivity, will facilitate accessing quantitative x-ray phase-contrast microtomography as a research tool across disciplines, including tissue engineering, materials science, and nondestructive testing in general

Advanced x-ray imaging techniques in tissue engineering: a new construct assessment platform for enabling the regeneration of personalised organs

Tissue engineering (TE) holds promise for generating lab-grown patient specific organs which can provide: (1) effective treatment for conditions that require volumetric tissue transplantation and (2) new platforms for drug testing. Even though volumetric structural information is essential for confirming successful organ maturation, TE protocol designs are currently informed through destructive and 2D construct assessment tools (e.g. histology). X-ray phase-contrast computed-tomography (PC-CT) can generate non-destructive, high resolution, 3D density maps of organ architecture. In this work, PC-CT is used as new imaging tool for guiding two TE protocols currently at the in-vitro testing stage. The first (1) involves cell-repopulation of an oesophageal scaffold, with the aim of using the regenerated construct for treating long-gap oesophageal atresia, whilst for the second (2) a lung-derived scaffold is populated with islets for regenerating a pancreas, with the “repurposed” lung offering a platform for diabetes drug testing. By combing 3D images and quantitative information, we were able to perform comprehensive construct evaluation. Specifically, we assessed volumetrically: (1) the cell-distribution within the regenerated oesophagi and (2) islet integration with the vascular tree of the lung-derived scaffold. This new information was proven to be essential for establishing corresponding TE protocols and enabled their progression to more advanced scale-up models. We are confident that PC-CT will provide the novel insights necessary to further progress TE protocols, with the next step being in-vivo testing. Crucially, the non-destructive nature of PC-CT will allow in-vivo assessments of TE constructs following their implantation into animal hosts, to investigate their successful integration

Advanced Imaging Techniques for the Monitoring of Innovative Approaches in Regenerative Medicine

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X-ray phase-contrast microtomography of soft tissues using a compact laboratory system with two-directional sensitivity

X-ray microtomography is a nondestructive, three-dimensional inspection technique applied across a vast range of fields and disciplines, ranging from research to industrial, encompassing engineering, biology, and medical research. Phasecontrast imaging extends the domain of application of x-ray microtomography to classes of samples that exhibit weak attenuation, thus appearing with poor contrast in standard x-ray imaging. Notable examples are low-atomic-number materials, like carbon-fiber composites, soft matter, and biological soft tissues.We report on a compact and cost-effective system for x-ray phase-contrast microtomography. The system features high sensitivity to phase gradients and high resolution, requires a low-power sealed x-ray tube, a single optical element, and fits in a small footprint. It is compatible with standard x-ray detector technologies: in our experiments, we have observed that single-photon counting offered higher angular sensitivity, whereas flat panels provided a larger field of view. The system is benchmarked against knownmaterial phantoms, and its potential for soft-tissue three-dimensional imaging is demonstrated on small-animal organs: a piglet esophagus and a rat heart.We believe that the simplicity of the setupwe are proposing, combined with its robustness and sensitivity, will facilitate accessing quantitative x-ray phase-contrast microtomography as a research tool across disciplines, including tissue engineering, materials science, and nondestructive testing in general

Supplementary document for T staging esophageal tumors with x-rays - 6907077.pdf

additional document with more dat