Holger Krakowski-Roosen

Contrast-enhanced ultrasound (CEUS) is able to quantify muscle perfusion and changes in perfusion due to muscle exercise in real-time. However, reliable measurement of standardized muscle exercise is difficult to perform in clinical examinations. We compared perfusion reserve assessed by CEUS after transient arterial occlusion and exercise to find the most suitable measurement for clinical application. Contrast pulse sequencing (7 MHz) during continuous IV infusion of SonoVue(®) (4.8 mL/300 s) was used in 8 healthy volunteers to monitor muscle perfusion of the gastrocnemius muscle during transient (1 min) arterial occlusion produced by a thigh cuff of a venous occlusion plethysmograph. Isometric muscle exercise (50% of individual maximum strength for 20s) was subsequently performed during the same examination, and several CEUS parameters obtained from ultrasound-signal-intensity-time curves and its calculation errors were compared. The mean maximum local blood volume after occlusion was 13.9 [∼mL] (range, 4.5-28.8 [∼mL]), and similar values were measured after sub-maximum exercise 13.8 [∼mL], (range, 4.6-22.2 [∼mL]. The areas under the curve during reperfusion vs. recovery were also similar (515.2±257.5 compared to 482.2±187.5 [∼mLs]) with a strong correlation (r=0.65), as were the times to maximum (15.3s vs. 15.9s), with a significantly smaller variation for the occlusion method (±2.1s vs. ±9.0s, p=0.03). The mean errors for all calculated CEUS parameters were lower for the occlusion method than for the exercise test. CEUS muscle perfusion measurements can be easily performed after transient arterial occlusion. It delivers data which are comparable to CEUS measurements after muscle exercise but with a higher robustness. This method can be easily applied in clinical examination of patients with e.g. PAOD or diabetic microvessel diseases to assess perfusion reserve.

Lowering high plasma levels of homocysteine (tHcy) by folate/vitamin-B-supplementation only unsufficiently protects against cardiovascular diseases and dementia. To enhance therapeutic options, we evaluated whether the significant tHcy-lowering effect of oral N-acetylcysteine (NAC) in sedentary adults (-11.71% [12]) is still detectable on a background of anabolic resistance training (RT) which moderately decreases tHcy itself. Reanalysing a previous randomized controlled double-blinded clinical trial, we compared the effect of oral NAC (8 weeks 1.8 g/d, n=9) to that of placebo (n=8) on postabsorptive tHcy in healthy middle-aged subjects (tHcy 11.82±0.69 µM) undergoing 8 weeks of supervised progressive RT. NAC (+RT) led to a significantly greater reduction of tHcy (-13.97±5.81%) than placebo (+RT) (-3.85±4.81%) as confirmed by ANOVA (P<0.05) adjusting for methionine plasma levels and gain in strength. This add-on effect of NAC (~-10%) suggests that combining cysteine supplementation with RT may offer a novel (additional) option to lower tHcy in an aging population.

Background The quality of computed tomography (CT) imaging is important when used to judge the success of joint replacement surgery. Metal artefacts are a known source of error, typically compensated by noise reduction software. Purpose To develop a transportable and stable system for the assessment of image quality of bone lesions around orthopedic implants. Material and Methods The design and manufacture of a bone-implant-phantom is described, which is based on a calf acetabulum with surrounding pelvic bone structures. Bone lesions of several sizes were created in the acetabulum before implanting the cup of an uncemented hip prosthesis, which was fixed with a stainless-steel bone screw. Plastic strips were placed on a cobalt–chromium stemmed femoral component, simulating typical bone lesions around loosening or infected prostheses, before embedding the stem in material similar to bone and shaped like a femur. The head of the femoral component was then placed in the acetabular cup ...

Background Dramatic weight loss is an often underestimated symptom in pancreatic cancer patients. Cachexia- defined as an unintended loss of stable weight exceeding 10% – is present in up to 80% of patients with cancer of the upper gastrointestinal tract, and has a significant influence on survival. The aim of the study was to show the multiple systemic effects of cachexia in pancreatic cancer patients, in terms of resection rate, effects on pulmonary function, amount of fat and muscle tissue, as well as changes in laboratory parameters. Methods In patients with pancreatic cancer, clinical appearance was documented, including the amount of weight loss. Laboratory parameters and lung-function tests were evaluated, and the thickness of muscle and fat tissue was measured with computed tomography scans. Statistical analysis, including multivariate analysis, was performed using SPSS software. Survival curves were calculated using Kaplan-Meier analysis and the log-rank test. To test for s...

The shapes of the CEUS curve during and after exercise differed individually depending on the performed muscle work. The maximum blood volume MAX was observed only after exercise cessation and was significantly correlated with the performed muscle force (r = 0.77, p < ...