Clinical Hemorheology and Microcirculation - Volume 52, issue 2-4

Authors: Helck, A. | Notohamiprodjo, M. | Danastasi, M. | Meinel, F. | Reiser, M. | Clevert, D.A.

Article Type: Research Article

Abstract: Purpose: To evaluate the feasibility of US image fusion in the clinical routine and to discuss potential benefits for follow-up after renal transplantation. Materials and methods: 15 patients with a renal transplant were prospectively included in the study. For all of them, a previously performed CT- or MRI-scan covering the renal transplant was available. Each patient was investigated using ultrasound image fusion. Time needed for sucessful implementation of image fusion was registered. Subsequently, quality of image fusion was assessed by two experienced radiologists (10 and 5 years of experience) in consensus using a subjective 5 point rank scale (1 = …best). Results: Image fusion was successfully performed in all patients. Time needed for setup of image fusion varied from 45–120 sec (85 ± 5 sec). The score for quality of US image fusion was 1.9 ± 0.7. Conclusion: Assessment of renal transplants using US image fusion is feasible and provides several potential benefits for the follow-up of renal transplants. Show more

Keywords: Ultrasound image fusion, renal transplant, image quality

DOI: 10.3233/CH-2012-1595

Citation: Clinical Hemorheology and Microcirculation, vol. 52, no. 2-4, pp. 179-186, 2012

Authors: Mueller, S. | Gosau, M. | Wendl, C.M. | Prantl, L. | Wiggermann, P. | Reichert, T.E. | Jung, E.M.

Article Type: Research Article

Abstract: Purpose: Quantitative measurement of dynamic contrast values obtained by contrast-enhanced ultrasound (CEUS) for evaluating microvascularization in osseous and osseocutaneous free flaps used for maxillofacial reconstructions. Patients and Methods: 22 patients (6 women, 16 men, mean age: 57 years, range: 47 to 82 years) who had received mandibular reconstructions with 3 avascular and 19 microvascular free osseous or osseocutaneous transplants were included in this trial. 16 patients had received a microvascular osseocutaneous fibular flap, 2 patients a microvascular osseous fibular flap and 1 patient a microvascular osseous iliac crest flap. Patients were followed up for 12 months on average (range: 3 …to 20 months). Ultrasound examination was carried out by one experienced examiner with a linear probe (6–9 MHz, LOGIQ E9, GE) after the intravenous bolus injection of 2.4 ml contrast agent (SonoVue® , BRACCO, Germany). Digital cine loops were analysed with a quantification software (VueBox™) for determining wash-in parameters: Rise Time (RT), Peak Enhancement (PE), Wash-in Area Under the Curve (WiAUC) and Wash-in Rate (WiR). Results were compared with the patients' postoperative clinical outcome. Results: For the bone area the median of the RT was 10.0 s (range 3.1 to 65.0 s), for the ratio between bone tissue and soft tissue for the PE the median was 10.4% (range 2.6 to 29.8%), the median for the WiAUC was 11.1% (range 1.5 to 77.7%) and the median for the WiR was 5.7 %(range 0.7 to 61.1%). None of the patients with microvascular osseocutaneous and osseous flaps showed any signs of transplant bone loss, which corresponded with the qualitative CEUS assessment. The patients with microvascular re-anastomosed transplants showed widely varying values for the investigated parameters (RT, PE, WiAUC, WiR). For patients with avascular bone transplants, these parameters were reduced to zero values for the bone area resulting in a significant difference (p < 0.05) for the PE compared to the patients with microvascular bone transplants. Conclusion: CEUS allowed the qualitative assessment of bone microvascularization by observing the transition of the contrast agent from the periostal area into the bone. However, defining a critical lower border by quantification of bone perfusion was difficult because of the inconstant perfusion of the bone transplants used in the trial. Show more

Keywords: Osseous flaps, osseocutaneous flaps, contrast-enhanced ultrasound, perfusion quantification

DOI: 10.3233/CH-2012-1596

Citation: Clinical Hemorheology and Microcirculation, vol. 52, no. 2-4, pp. 187-196, 2012

Authors: Hornung, Matthias | Jung, Ernst Michael | Georgieva, Martina | Schlitt, Hans J. | Stroszczynski, Christian | Agha, Ayman

Article Type: Research Article

Abstract: Background: Preoperative differentiation of thyroid nodules in benign and malignant pathologies still represents an unsolved problem in endocrinology. In the presented study, contrast-enhanced ultrasonography (CEUS) was applied as a new diagnostic tool detecting the microvascularisation of thyroid carcinomas. Methods: 167 patients underwent surgery for suspicious thyroid nodules between 05/2011 and 08/2012. Contrast-enhanced ultrasonography (CEUS) with a linear probe (6–9 MHz, LOGIQE9/GE), color coded Doppler sonography (CCDS) and Power Doppler ultrasonography (PD) were performed in all patients preoperatively. Removed nodules were proved by histology. In case of carcinoma morphological characteristics and especially microvascularization were analyzed using time intensity curves (TIC) in …selected regions of interest (ROI). Results: In total, 22 thyroid carcinomas could be identified by histology. Using CEUS thyroid carcinomas in 19 patients showed early and irregular arterial vascularization followed by early arterial central wash-out. CCDS/PD, however, revealed irregular peripheral vascularization with low flow only in 8 cases. Further analysis resulted in a significant higher area under the curve (AUC) at the edge than in the tumor center but in a similar time to peak (TTP) in both regions. Conclusions: CEUS represents a highly sensitive method for the detection of the microvascularization of thyroid carcinomas. Future studies should compare these findings to benign pathologies in order to establish CEUS as a standard diagnostic procedure in the preoperative evaluation of suspicious thyroid nodules. Show more

Keywords: Thyroid carcinoma, contrast-enhanced ultrasonography

DOI: 10.3233/CH-2012-1597

Citation: Clinical Hemorheology and Microcirculation, vol. 52, no. 2-4, pp. 197-203, 2012

Authors: Clevert, D.A. | Paprottka, P.M. | Helck, A. | Reiser, M. | Trumm, C.G.

Article Type: Research Article

Abstract: Purpose: The purpose of this study was to evaluate whether image fusion with contrast enhanced ultrasound (CEUS) and CT is effective in the pre-, intra- and post-interventional management of liver lesions during microwave or radiofrequency ablation. Methods and materials: Fifteen patients with a single hepatocellular carcinoma (HCC) up to 3 cm diameter, identified on both contrast-enhanced CT (Siemens Somatom Definition AS and Definition Edge, Siemens Healthcare, Erlangen, Germany) and ultrasound (Siemens ACUSON S2000™ or S3000™, Siemens Healthcare, Erlangen, Germany) were retrospectively enrolled between July 2011 and May 2012. Either automatic registration or plane match registration was chosen on CT and …ultrasound for the pre-, intra- and postinterventional management of all treated liver lesions during microwave or radiofrequency ablation. Using conventional ultrasound B-mode, CEUS and image fusion including B-mode and CEUS the detectability of the liver lesions was evaluated semi-quantitatively by comparing the image sequences in a consensus reading. Eight patients underwent radiofrequency ablation and seven patients underwent microwave ablation. Results: All patients were examined using all diagnostic ultrasound tools of the study. The results show that the procedure is easy and convenient to perform, as well as efficient. The co-registration procedure took approximately 5 to 10 minutes depending on the amount of DICOM volume-data and the habitus of the patient. The results show that the use of image fusion with CT and contrast-enhanced ultrasound could improve the diagnostic assessment capabilities in comparison to the examination without image fusion in the pre-, intra- and postinterventional management of malignant liver lesions during thermal ablation. Conclusion: Percutaneous thermal ablation guided by contrast-enhanced ultrasound and image fusion seems to be an efficient approach for malignant liver lesions especially if these are not clearly demarcated by B-mode. The use of the image fusion technique in the pre-, intra- and postinterventional management can increase operator confidence, the accuracy of the procedure, and technical success in real time. Show more

Keywords: Image fusion, radiofrequency ablation, microwave ablation, interventional radiology, hepatocellular carcinoma

DOI: 10.3233/CH-2012-1598

Citation: Clinical Hemorheology and Microcirculation, vol. 52, no. 2-4, pp. 205-216, 2012

Authors: Knaut, M. | Matschke, K. | Plötze, K. | Steinmann, C. | Mrowietz, C. | Jung, F.

Article Type: Research Article

Abstract: Heart failure patients are clinically characterized by extreme cardiomegaly, breathlessness, fluid retention and an early onset of fatigue. Studies have shown generalized restricted blood flow in those patients. Furthermore animal experiments proved an impaired blood flow and a diminished oxygen supply of the skeletal muscle in animals with chronic heart failure. Patients with chronic heart failure are limited to the extent of their ability to regulate their arterial pressure, especially in physical activity. It is however unclear in what way restriction of blood flow in the main arteries correlates with those in capillaries and to what extent. In this study …it was examined the depth of capillary circulatory restriction as well as the disregulation of oxygen partial pressure in skeletal muscle in rest and stress conditions, in patients with terminal heart failure. Show more

Keywords: Microcirculation, end stage heart failure, skeletal muscle

DOI: 10.3233/CH-2012-1599

Citation: Clinical Hemorheology and Microcirculation, vol. 52, no. 2-4, pp. 217-227, 2012

Authors: Franke, R.P. | Fuhrmann, R. | Hiebl, B. | Jung, F.

Article Type: Research Article

Abstract: Various radiographic contrast media (RCM) are available for visualization of blood vessels in interventional cardiology which can vary widely in their physicochemical properties thereby influencing different functions of blood cells. In the in vitro study described here the influence of two RCMs on arterial as well as on venous endothelial cells was compared to control cultures and examined under statical culture conditions, thus eliminating the influence of RCM viscosity almost completely. The supplementation of the culture medium with RCM (30% v/v) resulted in clearly different reactions of the endothelial cells exposed. Exposition to Iodixanol supplemented culture medium was followed by …endothelin-1 release from venous endothelial cells which was equivalent to the endothelin-1 release from venous control cultures. Compared to control cultures, venous endothelial cells exposed to culture medium supplemented with Iomeprol displayed a completely different reaction, the increase in endothelin-1 secretion was missing completely after a 12 hours exposure. Following a 12 hours exposure to both RCMs there were no longer endothelial cells adherent, neither in venous nor in arterial endothelial cell cultures. The study showed that not the wall shear stress was responsible for the differing effects visible after 1.5 min, 5 min, and 12 hours exposure to culture media supplemented with RCM but differences in chemotoxicity of the RCM applied. Show more

Keywords: Endothelin-1, angiographic contrast media, primary human endothelial cells, extracellular matrix

DOI: 10.3233/CH-2012-1600

Citation: Clinical Hemorheology and Microcirculation, vol. 52, no. 2-4, pp. 229-234, 2012

Authors: Schaefer, Sarina | Muxel, Selina | Fasola, Federica | Beutel, Alica | Forconi, Sandro | Parker, John D. | Münzel, Thomas | Gori, Tommaso

Article Type: Research Article

Abstract: Previous studies from our and other laboratories have demonstrated the existence of a clear relationship between different measures of endothelial function and the extent of coronary atherosclerosis. The relationship between endothelial function and carotid intima-media thickness has not been extensively investigated. Endothelial function using radial artery flow-mediated constriction (L-FMC) and dilation (FMD) was assessed in 513 consecutive patients undergoing diagnostic coronary angiography. Intima-media thickness of both carotid arteries was also measured. IMT was greater in patients with diabetes, males, those with body mass index >30, and in those older than 65 years (all p < 0.05). There was a strong …correlation between age and IMT (p < 0.0001). Hypercholesterolemia and a family history for cardiovascular disease had no impact on IMT. In contrast, the relationship between either L-FMC or FMD and IMT was weak at best (p = 0.008 for the relationship between L-FMC and IMT, p = 0.13 for the relationship between FMD and IMT). There was a positive correlation between IMT and resting radial artery diameter (p = 0.008). IMT increased with the extent of coronary artery disease, but this trend did not reach statistical significance (p = 0.07). Resting (L-FMC), but not recruitable (FMD) endothelial function correlates with the extent of subclinical carotid atherosclerosis. This correlation is however weaker in comparison to that with age. Show more

Keywords: Cerebral circulation, endothelial function, atherosclerosis

DOI: 10.3233/CH-2012-1601

Citation: Clinical Hemorheology and Microcirculation, vol. 52, no. 2-4, pp. 235-243, 2012

Authors: Vosseler, Markus | Beutel, Alica | Schäfer, Sarina | Muxel, Selina | Jabs, Alexander | Forconi, Sandro | Parker, John D. | Münzel, Thomas | Gori, Tommaso

Article Type: Research Article

Abstract: While the role of physical forces on the control of atherogenesis and the modulation of endothelial function is well known, studies investigating the impact of shear stress on the extent of central atherosclerosis and flow-mediated dilation in humans produced controversial results. We investigated the relationship between viscosity, coronary atherosclerosis, carotid intima-media thickness and flow-mediated dilation in patients undergoing coronary angiography. 451 patients (306 males, mean age 66 ± 10) were enrolled. Viscosity, which was calculated using a validated formula, showed a positive association with platelet activation (P = 0.01), leukocyte counts (P = 0.006) and C-reactive protein (P = 0.03), …a marker of inflammation; surprisingly, visocsity showed a negative association with FMD (FMD decreased 0.14 ± 0.05% per each cPoise increase in viscosity) but only in patients without coronary artery disease. Viscosity showed no association with the extent of coronary or carotid artery disease. We provide cross-sectional data on the relationship between whole blood viscosity and parameters of vascular structure and function. While viscosity correlated with parameters of vascular inflammation, it showed no relationship with the presence and severity of central atherosclerosis. Show more

Keywords: Coronary slow flow, endothelial function, viscosity, hematocrit, platelets

DOI: 10.3233/CH-2012-1602

Citation: Clinical Hemorheology and Microcirculation, vol. 52, no. 2-4, pp. 245-254, 2012

Authors: Gori, Tommaso | Damaske, Ana | Muxel, Selina | Radmacher, Marie-Christine | Fasola, Federica | Schaefer, Sarina | Fineschi, Massimo | Forconi, Sandro | Jung, Friedrich | Münzel, Thomas | Parker, John D.

Article Type: Research Article

Abstract: Background: Coronary (micro)vascular resistance is regulated by the complex interplay of several factors. Two potentially important determinants include endothelial function and the rheological properties of blood. However, their impact on the control of the coronary resistance vasculature is poorly understood. Methods: The corrected Thrombolysis In Myocardial Infarction frame count (TIMIfc, an index of coronary flow velocity), conduit artery endothelial function, intima-media thickness of the common carotid artery and complete blood counts were measured in 145 patients undergoing elective coronary angiography. Patients with obstructive coronary artery disease or systemic conditions thought to be associated with microvascular disease were excluded from the …analysis. Results: There was a strong correlation between the TIMIfc measured in the three main coronary artery distributions (R values between 0.71 and 0.85, P < 0.00001). The TIMIfc was higher in males (P < 0.05), but there was no association with traditional risk factors for coronary artery disease (all P > 0.1). There was a correlation between TIMIfc and L-FMC, a parameter of resting endothelial function (R = 0.33, P < 0.0005). TIMIfc also correlated with mean platelet volume (a marker of platelet activation, R = 0.33, P < 0.001), and hematocrit (R = 0.33, P = 0.0002). There was no correlation between TIMIfc and carotid intima-media thickness and the degree of coronary atherosclerosis. Logistic regression analysis showed that L-FMC and hemorheological variables may explain as much as 19% of the variability in TIMIfc. Conclusions: Resting peripheral endothelial function, as well as parameters of platelet function, correlate with coronary TIMIfc. These data emphasize the existence of an association between endothelial function, hemorheological variables and coronary blood flow velocity. Show more

Keywords: Coronary blood flow, endothelial function, platelets, hematocrit

DOI: 10.3233/CH-2012-1603

Citation: Clinical Hemorheology and Microcirculation, vol. 52, no. 2-4, pp. 255-266, 2012

Authors: Schulz, C. | von Rüsten-Lange, M. | Krüger, A. | Lendlein, A. | Jung, F.

Article Type: Research Article

Abstract: Poly(ether imide) (PEI) is being explored as potential biomaterial for cardiovascular applications. Different studies showed that human umbilical venous endothelial cells (HUVEC) are able to adhere and proliferate on PEI membranes (Rq = 13.20 ± 1.58 nm). A recently published study revealed evidence for much lower platelet adhesion on very smooth PEI-films (Rq = 2.37 ± 1.40 nm). Therefore, we explored whether primary human venous endothelial cells (HUVEC) are able to adhere and proliferate on such very smooth PEI-films compared to tissue-cultured polystyrene (TCP) as reference material. Cytotoxicity testing revealed that PEI had a slight cytotoxic effect on …HUVEC accompanied by a marginal reduced integrity of the plasma membrane and a significant lower mitochondrial activity. However long-term seeding experiments up to eleven days exhibited that HUVEC were able to proliferate on the PEI-films till confluence (TCP 96,190 ± 18,289 cells/cm2 ; PEI 91,590 ± 19,583 cells/cm2 ). Further studies are planned to monitor the influence of shear force on the endothelial cell monolayer in a dynamic test system to determine its stability in view of shear resistant endothelialization of PEI for cardiovascular devices. Show more

Keywords: Biomaterial, Poly(ether imide), biocompatibility, endothelialization

DOI: 10.3233/CH-2012-1604

Citation: Clinical Hemorheology and Microcirculation, vol. 52, no. 2-4, pp. 267-282, 2012