A laboratory-based beam tracking x-ray imaging method achieving two-dimensional phase sensitivity and isotropic resolution with unidirectional undersampling.

Beam tracking X-ray Phase Contrast Imaging is a "Shack-Hartmann" type approach which uses a pre-sample mask to split the x-rays into "beamlets" which are interrogated by a detector with sufficient resolution. The ultimate spatial resolution is determined by the size of the mask apertures, however achieving this resolution level requires "stepping" the sample or the mask in increments equal to the aperture size ("dithering"). If an array of circular apertures is used (which also provides two-dimensional phase sensitivity) instead of long parallel slits, this stepping needs to be carried out in two directions, which lengthens scan times significantly. We present a mask design obtained by offsetting rows of circular apertures, allowing for two-dimensional sensitivity and isotropic resolution while requiring sample or mask stepping in one direction only. We present images of custom-built phantoms and biological specimens, demonstrating that quantitative phase retrieval and near aperture-limited spatial resolutions are obtained in two orthogonal directions.

Operative technique and morbidity of superficial femoral vein harvest.

BACKGROUND: The use of autologous superficial femoral veins (SFV) as an arterial or venous substitute represents a valuable technique in modern vascular surgery with versatile indications. The SFV autografts exhibit excellent control of infection and durable long-term results in terms of graft patency in prosthetic or arterial infections. In cases of elective use of the SFV, duplex ultrasound evaluation of the deep leg vein system should be implemented to confirm the patency of the profunda femoris vein. MATERIAL AND METHODS: The SFV can be harvested distal to the adductor hiatus with a proximal portion of the popliteal vein but should not exceed the level of the knee joint. Formation of a stump of the proximal SFV must be avoided. Simultaneous harvesting of the ipsilateral greater saphenous vein should be avoided to reduce the risk of significant chronic edema. RESULTS: Early postoperative swelling of the donor leg can be expected but resolves spontaneously in most cases. Chronic mild edema of the leg with a possible indication for compression therapy may occur in up to 20 % of cases but severe complications are very rare if the anatomical borders for vein harvesting are respected. Temporary therapeutic anticoagulation after vein harvest is subject to individual decision making. CONCLUSION: Duplex ultrasound is a reliable tool to assess the residual deep and superficial venous system in the long term. Excellent graft function and the tolerable adverse effects of vein harvest on the donor leg justify the use of the SFV in arterial and venous vascular surgery if indicated.

[Peripheral artery disease as supplemental diagnosis in coronary heart disease--influence on diagnostics, treatment and prognosis]. / Periphere arterielle Verschlusskrankheit als Zusatzdiagnose bei koronarer Herzerkrankung--Einfluss auf Diagnostik, Therapie und Prognose.

Peripheral arterial disease (PAD) increases cardiovascular event rate in patients with coronary artery disease (CAD). Therefore PAD should be considered in patients with CAD with regard to diagnostic and therapeutic strategies. PAD may difficult diagnostic tests in CAD patients. Patients with PAD and CAD may be limited in stress testing by decreased leg perfusion. In addition, arterial puncture can be more difficult in sclerotic femoral arteries. Cardiovascular risk factors should be treated carefully in all manifestations of atherosclerosis. Target values from current guidelines are similar for PAD and CAD. Inhibitors of platelet aggregation are indication in both CAD and PAD. Exercise not only improves walking distance in patients with intermittent claudication but also improves cardiovascular prognosis in patients with atherosclerosis.

[Peripheral arterial disease: epidemiology, symptoms and diagnosis]. / Periphere arterielle Verschlusskrankheit: Epidemiologie, Klinik und Diagnostik.

Peripheral arterial disease (PAD) is highly prevalent. Patients with PAD have often manifestations of atherosclerosis in other vascular territories and are at increased risk for cardiovascular events. Typical symptoms are intermittent claudication or rest pain and acral lesions in patients with advanced PAD. The majority of PAD patients is clinically asymptomatic, therefore it makes sense to look for PAD in patients with cardiovascular risk factors. The ankle brachial index (ABI = ankle/arm pressure) is regarded as an easy and cost effective method for baseline diagnostic. If ABI measurement confirms the suspected PAD, a detailed diagnostic pathway should follow in which duplex sonography plays a central role. In some cases additional radiologic imaging is necessary to complete the diagnostic or to plan therapeutic procedures.

Infrapopliteal composite bypass with autologous vein and second generation glutaraldehyde stabilized human umbilical vein (HUV) for critical lower limb ischaemia.

OBJECTIVE: To audit a single center consecutive series of infrapopliteal composite bypasses with second generation glutaraldehyde stabilized human umbilical vein. DESIGN: Retrospective study. PATIENTS: From January 1996 to July 2006 89 femoro-distal bypasses were constructed in 85 patients with HUV and residual vein segments as composite grafts in the absence of sufficient length of autologous vein. METHODS: All patients with infrainguinal bypass operations were registered prospectively. Bypasses to infrapopliteal arteries performed with HUV-composite grafts were reviewed for graft patency, limb salvage, patient survival and possible biodegeneration of the HUV. RESULTS: Early graft thrombosis was noted in 21.3%, necessitating revision surgery. Primary, primary assisted and secondary patency rates were 35%, 40% and 42% respectively, with a limb salvage rate of 87% after 5 years. Graft infection occurred in 7 limbs. Aneurysmal HUV graft degeneration was not detected by duplex scanning. CONCLUSION: HUV-composite bypasses provide acceptable patency and favorable limb salvage rates. Patency was similar to previous series using PTFE-composite bypasses but was significantly inferior to vein bypass. Possible biodegradation of the HUV grafts seems to be of minor clinical relevance.

Sequential femorodistal composite bypass with second generation glutaraldehyde stabilized human umbilical vein (HUV).

OBJECTIVE: To evaluate the performance of sequential composite bypasses with second generation glutaraldehyde stabilized human umbilical vein (HUV) and autologous vein. DESIGN: Retrospective study of consecutive patients, in a single centre. PATIENTS: From January 1998 to December 2003, 54 femoro-distal HUV-autologous vein sequential composite bypasses were constructed in 52 patients with critical leg ischemia and absence of sufficient length of autologous vein. METHODS: All infra-inguinal bypass operations were registered in a computerized database and prospectively followed. Bypasses using sequential HUV-composite technique were reviewed for graft patency, limb salvage and patient survival. RESULTS: Primary patency and secondary patency rates at 1, 2, 3 and 4 years were 71, 61, 53 and 53% and 89, 80, 73 and 67%, respectively. Corresponding limb salvage rates were 96, 92, 88 and 88%. Patient survival was 56% at 4 years. After 30 days additional procedures to maintain graft patency were necessary in six bypasses. Asymptomatic occlusion of one sequential anastomosis was found in five patients. CONCLUSION: Graft patency and limb salvage rate support the use of the sequential composite technique with second generation HUV in femorodistal bypass surgery, when autologous vein of sufficient length is not available.