Clinical Hemorheology and Microcirculation - Volume 64, issue 4

Authors: Schulz, Christian | Vukićević, Radovan | Krüger-Genge, Anne | Neffe, Axel T. | Lendlein, Andreas | Jung, Friedrich

Article Type: Research Article

Abstract: The formation of a functionally-confluent and shear-resistant endothelial cell (EC) monolayer on cardiovascular implants is a promising strategy to prevent thrombogenic processes after implantation. On the basis of existing studies with arterial endothelial cells adhering after two hours on gelatin-based hydrogels in marked higher numbers compared to tissue culture plates, we hypothesized that also venous endothelial cells (HUVEC) should be able to adhere and form an endothelial monolayer on these hydrogels after days. Furthermore, variation of the hydrogel composition, which slightly influences the materials elasticity and even more the degradation behaviour, should have no considerable effect on HUVEC. Therefore, the …monolayer formation and shear resistance of HUVEC were explored on two gelatin-based hydrogels differing in their elasticity (Young’s moduli between 35 and 55 kPa) in comparison to a positive control (HUVEC on glass cover slips) and a negative control (HUVEC on glass cover slips activated with interleukin-1β) after 9 days of culturing. HUVEC density after 9 days of culturing under static conditions was lower on the hydrogels compared to both controls (p  < 0.05 each). On G10_LNCO8 slightly more EC adhered than on G10_LNCO5. Staining of the actin cytoskeleton and VE-cadherin revealed a pronounced cell-substrate interaction while the cell-cell interaction was comparable to the controls (HUVEC on glass). The secretion of vasoactive and inflammatory mediators did not differ between the hydrogels and the controls. Adherent HUVEC seeded on the hydrogels were able to resist physiological shear forces and the release of cyto- and chemokines in response to the shear forces did not differ from controls (HUVEC on glass). Therefore, both gelatin-based hydrogels are a suitable substrate for EC and a promising candidate for cardiovascular applications. Show more

Keywords: Endothelial cells, biomaterial, gelatin, hydrogel, shear stress

DOI: 10.3233/CH-168007

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 699-710, 2016

Authors: Zimmermann, H. | Rübenthaler, J. | Paprottka, P. | Paprottka, K.J. | Reiser, M. | Clevert, D.A.

Article Type: Research Article

Abstract: Currently methods to reduce radiation and contrast media application in endovascular repair of aortic aneurysms (EVAR) are investigated. First positive results for real-time contrast medium–enhanced ultrasonography (CEUS) guided endovascular aortic repair have been reported. A combination with image fusion of CEUS and preoperative multi-slice computed tomography (MS-CT) might offer added safety regarding stent-graft positioning and sealing of the landing zones. EVAR was performed in a patient with an asymptomatic infrarenal aortic aneurysm and a penetrating aortic ulcer in the neck region. The precise placement of the stent-graft was performed with CEUS using image fusion and native intraprocedural angiographic fluoroscopy and confirmed with …digital subtraction angiography (DSA) using iondinated contrast media. At follow-up, CEUS was used to exclude endoleaks and stent-graft failure or malposition. The precise CEUS-guided placement of the stent-graft was technically successful. No artifacts due to electrical noise and metallic parts of the operating table and surgical instruments occurred. The amount of iodinated contrast media was reduced as intraoperative follow-up was performed using CEUS. CEUS with image fusion combined with intraprocedural angiographic fluoroscopy enables accurate stent-graft placement without use of any nephrotoxic contrast media. This allows EVAR in patients with renal insufficiency or allergic reactions to contrast media. Show more

DOI: 10.3233/CH-168045

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 711-719, 2016

Authors: Marcon, J. | Trottmann, M. | Rübenthaler, J. | Stief, C.G. | Reiser, M.F. | Clevert, D.A.

Article Type: Research Article

Abstract: INTRODUCTION: Shear wave elastography (SWE) is a recent technique in the assessment of tissue elasticity. Different elastography techniques have been described over the years. Acoustic Radiation Force Impulse Imaging (ARFI) uses mechanical excitation of tissue to create detectable shear waves, a higher shear wave velocity being associated with an increased tissue stiffness. The Virtual Touch Tissue Imaging Quantification (VTIQ) method uses a mechanical push pulse as well, additionally creating a colour-coded map, in which tissue stiffness can be measured within a stored map on the ultrasound device after measurement. ARFI has been used in determining standard …values in testes of a healthy study collective, VTIQ has already been used in the evaluation of unclear scrotal masses. Both techniques allow an operator-independent examination without application of mechanical pressure. The aim of this study was to determine whether there is a statistically significant difference between shear wave velocity values of both techniques in a healthy collective. MATERIAL AND METHODS: Twenty patients without known testicular pathology underwent standard B-mode sonography and additional shear wave elastography in the ARFI mode as well as the VTIQ technique of both testes using the Siemens Acuson S2000™ and S3000™ ultrasound devices (Siemens HealthCare, Erlangen, Germany). Measurements of shear wave velocity were performed in the upper pole, the central portion and the lower pole separately for each testis. Values were described in m/s. Statistical evaluation was performed using paired t -test analysis. RESULTS: We measured a mean shear wave velocity of 0.81 m/s using ARFI and 1.07 m/s with VTIQ. Shear wave velocities determined by VTIQ were all significantly higher than values gained in the ARFI mode. (p  < 0.001 to p  = 0.007). Values were between 0.22 and 0.29 m/s higher, when the examination was performed using VTIQ. CONCLUSION: ARFI and VTIQ elastography modes both proved to be feasible techniques in the assessment of testicular tissue elasticity. Consideration of higher values for VTIQ is important, when different elastography measurement results are compared, especially for the application of devices in a clinical setting, e.g. in the work-up of scrotal masses. A calculable factor for a comparison between both devices is desirable, but to be further assessed in largerstudies. Show more

Keywords: Testis, ARFI, VTIQ, shear wave elastography, ultrasonography

DOI: 10.3233/CH-168052

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 721-728, 2016

Authors: Trottmann, M. | Rübenthaler, J. | Marcon, J. | Stief, C.G. | Reiser, M.F. | Clevert, D.A.

Article Type: Research Article

Abstract: PURPOSE: To investigate the difference of standard values of Supersonic shear imaging (SSI) and Acoustic Radiation Force Impulse (ARFI) technique in the evaluation of testicular tissue stiffness in vivo . MATERIALS AND METHODS: 58 healthy male testes were examined using B-mode sonography and ARFI and SSI. B-mode sonography was performed in order to scan the testis for pathologies followed by performance of real-time elastography in three predefined areas (upper pole, central portion and lower pole) using the SuperSonic® Aixplorer ultrasound device (SuperSonic Imagine, Aix-en-Provence, France). Afterwards a second assessment of the same testicular regions by elastography …followed using the ARFI technique of the Siemens Acuson 2000™ ultrasound device (Siemens Health Care, Germany). Values of shear wave velocity were described in m/s. Parameters of elastography techniques were compared using paired sample t -test. RESULTS: The values of SSI were all significantly higher in all measured areas compared to ARFI (p  < 0.001 to p  = 0.015). Quantitatively there was a higher mean SSI wave velocity value of 1,1 compared to 0.8 m/s measured by ARFI. CONCLUSION: SSI values are significantly higher than ARFI values when measuring the stiffness of testicular tissue and should only be compared with caution. Show more

Keywords: Testis, shear-wave elastography, ultrasonography

DOI: 10.3233/CH-168039

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 729-733, 2016

Authors: Platz Batista da Silva, N. | Schauer, M. | Hornung, M. | Lang, S. | Beyer, L.P. | Wiesinger, I. | Stroszczynski, C. | Jung, E.M.

Article Type: Research Article

Abstract: OBJECTIVE: To evaluate the efficacy of strain elastography (SE) using semi-quantitative measurement methods compared to constrast enhanced ultrasound during liver tumor surgery (Io-CEUS) for dignity assessment of focal liver lesions(FLL). MATERIAL AND METHODS: Prospective data acquisition and retrospective analysis of US data of 100 patients (116 lesions) who underwent liver tumor surgery between 10/2010 and 03/2016. Retrospective reading of SE color patterns was performed establishing groups depending on dominant color (>50% blue = stiff, inhomogenous, >50% yellow/red/green = soft tissue). Semi-quantitative analysis was performed by Q-analysis based on a scale from 0 (soft) to 6 (stiff). 2 ROIs were placed centrally, …5 ROIs in the lesion’s surrounding tissue. Io-CEUS was performed by bolus injection of 5–10 ml sulphurhexaflourid microbubbles evaluating wash-in- and -out- kinetics in arterial, portal venous and late phase. Histopathology after surgical resection served as goldstandard. RESULTS: 100 patients (m: 65, f: 35, mean age 60.5 years) with 116 liver lesions were included. Lesion’s size ranged from 0.5 to 8.4 cm (mean 2.42 cm SD±1.44 cm). Postoperative histology showed 105 malignant and 11 benign lesions. Semi-quantitative analysis showed central indurations of >2.5 in 76/105 cases suggesting malignancy. 7 benign lesions displayed no central indurations correctly characterized benign by SE. ROC-analysis and Youden index showed a sensitivity of 72.4% and specificity of 63.6% assuming a cut-off of 2.5. Io-CEUS correctly characterized 103/105 as malignant. Sensitivity was 98%, specificity 72.7%. CONCLUSION: Strain elastography is a valuable tool for non-invasive characterization of FLLs. Semi-quantitative intratumoral stiffness values of >2.5 suggested malignancy. However, sensitivity of Io-CEUS in detecting malignant lesions was higher compared to SE. In conclusion SE should be considered for routine use during intraoperative US in addition to Io-CEUS for optimization of curative liver surgery. Show more

Keywords: Ultrasound, elastography, surgery, CEUS, strain elastography

DOI: 10.3233/CH-168029

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 735-745, 2016

Authors: Wiesinger, I. | Kroiss, E. | Zausig, N. | Hornung, M. | Zeman, F. | Stroszczynski, C. | Jung, E.M.

Article Type: Research Article

Abstract: AIM: To determine different perfusion characteristics of histo-pathologically proven adenomas and carcinomas of the thyroid gland with CEUS and perfusion software. MATERIAL AND METHODS: Retrospective perfusion analysis of 25 patients with carcinomas and 41 cases of adenomas of the thyroid gland (30 males, 36 females; aged 18 – 85 years, mean 56 years). All cases were histologically analyzed. Perfusion analysis was independently performed using external perfusion software (VueBox® ). TTP, mTT, Peak and Rise time were calculated. RESULTS: Lesions’ sizes ranged from 0.2 to 10.2 cm in carcinomas (mean 2.18 cm), and from 0.6 to 5.0 cm in …adenomas (mean 2.25 cm). In 20 out of 25 carcinomas that were evaluated with CEUS, a complete wash-out in the late venous phase was found. Adenomas showed wash-out at the border. Perfusion analysis in VueBox® revealed some parameters which tend to show differences between adenomas and carcinomas, however did not reach the level of significance. Median Peak in carcinomas was highest at the margins (2945 rU), and lowest in the surroundings (1110 rU). Mean Transit Time (mTT) values showed no differences between center, margin and surrounding. In adenomas healthy tissue showed higher mTT values compared to the center (24.6 vs. 20.7 sec). Median Peak was highest in the surrounding tissue and lowest in the margins (1999 vs. 1129 rU). No statistical differences could be found in the comparisons. CONCLUSION: CEUS with perfusion analysis offers new possibilities for the dynamic evaluation of micro-vascularization in thyroid adenomas and carcinomas. Using VueBox® the perfusion analysis of the arterial phase provides new parameters that help determine a lesion’s malignancy or benignity. However a final assessment regarding malignancy and benignity of thyroid lesions using only CEUS and perfusion analysis of the arterial phase is not yet possible. Show more

Keywords: Thyroid, CEUS, perfusion, micro-vascularization

DOI: 10.3233/CH-168044

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 747-755, 2016

Authors: Rübenthaler, J. | Paprottka, K. | Marcon, J. | Hameister, E. | Hoffmann, K. | Joiko, N. | Reiser, M. | Clevert, D.A.

Article Type: Research Article

Abstract: PURPOSE: To compare the sensitivity and specificity of contrast-enhanced ultrasound (CEUS) and magnetic resonance imaging (MRI) in the evaluation of unclear renal lesions to the histopathological outcome. MATERIALS AND METHODS: A total of 36 patients with a single unclear solid renal lesion with initial imaging studies between 2005 and 2015 were included. CEUS and MRI were used for determining malignancy or benignancy and initial findings were correlated with the histopathological outcome. Out of the 36 renal masses a total of 28 lesions were malignant (77.8%) and 8 were found to be benign (22.2%). Diagnostic accuracy was testes …by using the histopathological diagnosis as the gold standard. RESULTS: CEUS showed a sensitivity of 96.4%, a specificity of 100.0%, a positive predictive value (PPV) of 100.0% and a negative predictive value (NPV) of 88,9%. MRI showed a sensitivity of 96.4%, a specificity of 75.0%, a PPV of 93.1% and a NPV of 85.7%. Out of the 28 malignant lesions a total of 18 clear cell renal carcinomas, 6 papillary renal cell carcinomas and 4 other malignant lesions, e.g. metastases, were diagnosed. Out of the 8 benign lesions a total 3 angiomyolipomas, 2 oncocytomas, 1 benign renal cyst and 2 other benign lesions, e.g. renal adenomas were diagnosed. Using CEUS, 1 lesion was falsely identified as benign. Using MRI, 2 lesions were falsely identified as benign and 1 lesion was falsely identified as malignant. CONCLUSION: CEUS is an useful method which can be additionally used to clinically differentiate between malignant and benign renal lesions. CEUS shows a comparable sensitivity, specificity, PPV and NPV to MRI. In daily clinical routine, patients with contraindications for other imaging modalities can particularly benefit using this method. Show more

Keywords: Contrast-enhanced ultrasound (CEUS), magnetic resonance imaging (MRI), solid renal lesions

DOI: 10.3233/CH-168034

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 757-763, 2016

Authors: Nemeth, Norbert | Peto, Katalin | Deak, Adam | Sogor, Viktoria | Varga, Gabor | Tanczos, Bence | Balog, Klaudia | Csiszko, Adrienn | Godo, Zoltan | Szentkereszty, Zsolt

Article Type: Research Article

Abstract: BACKGROUND: Abdominal compartment syndrome (ACS) is a life-threatening condition, of which pathomechanism hasn’t been completely clarified, yet. Furthermore, surgical therapy still needs optimization. OBJECTIVE: We aimed to investigate microcirculatory and micro-rheological alterations in ACS, using various temporary abdominal closure methods, including three settings of vacuum-assisted closure technique (negative pressure wound therapy, NPWT). METHODS: On anesthetized pigs, by intraabdominally placed and filled-up silicone bags, intraabdominal pressure at 30 mmHg was maintained for 3 hours, and afterwards, decompressive laparotomy happened. In different experimental groups Bogota-bag or Vivano abdominal sets were applied (–50, –100, –150 mmHg) for 2 hours. Pressure monitoring was …done by implanted sensors, hemorheological parameters were determined, and laser Doppler flowmetry tests were performed on the surface of intraabdominal organs. RESULTS: Treatment with Bogota-bag and –150 mmHg vacuum increased erythrocyte aggregation, while deformability declined. Blood viscosity increased after treatment with –150 mmHg vacuum. The microcirculatory parameters of the NPWT groups were better in small intestine. CONCLUSIONS: ACS resulted in impairment of macro- and micro-rheological parameters and abdominal organs’ microcirculation. All of the used techniques improved the results, however, applying Bogota-bag or –150 mmHg vacuum set showed worse microcirculatory and micro-rheological data than the settings at –100 or –50 mmHg. Show more

Keywords: Abdominal compartment syndrome, negative pressure wound therapy, microcirculation, hemorheology

DOI: 10.3233/CH-168027

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 765-775, 2016

Authors: Brun, Jean-Frédéric | Varlet-Marie, Emmanuelle | Raynaud de Mauverger, Eric

Article Type: Research Article

Abstract: The hemorheological theory of optimal hematocrit suggests that the best value of hematocrit (hct) should be that which results in the highest value of the hematocrit/viscosity (h/η) ratio. Trained athletes compared to sedentary subjects have a lower hct, but a higher h/η, and endurance training reduces the discrepancy between the actual hct and the ⪡ideal⪢ hct that can be predicted with a theoretical curve of h/η vs hct constructed with Quemada’s model. In this study we investigated what becomes this homeostasis of h/η and hct during acute exercise in 19 athletes performing a 25 min exercise test. VO2max is …negatively correlated to resting hct and positively correlated to discrepancy between actual and ideal resting hct which is correlated to the maximal rise in hct during exercise. Predicted and actual values of the h/η were fairly correlated (r  = 0.970 p  < 0.001) but the actual value was lower at rest and this discrepancy vanished at 25 min exercise. Exercise-induced decrease in discrepancy between actual and theoretical h/η was negatively correlated with the score of overtraining. All these findings suggest that h/η is a regulated parameter and that its model-predicted ⪡optimal⪢ values yield a ⪡theoretical optimal⪢ hct which is close to the actual value and even closer when athletes are well trained. In addition, acute exercise sets h/η closer from its predicted ideal value and this adaptation is impaired when athletes quote elevated scores on the overtraining questionnaire. Show more

Keywords: Blood viscosity, hematocrit, exercise, erythrocyte deformability, hematocrit/viscosity ratio

DOI: 10.3233/CH-168012

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 777-787, 2016

Authors: Brun, Jean-Frédéric | Boulot, Pierre | Varlet-Marie, Emmanuelle

Article Type: Research Article

Abstract: Physiological studies on fetal blood in narrow glass tubes have suggested that fetal optimal hematocrit (hct) might be as high as 60%. A theoretical ‘ideal’ hct can also be predicted with a theoretical curve of hematocrit/viscosity (h/η ) ratio vs hct constructed with Quemada’s model. We used the database of one of our previous papers on fetal hemorheology to reinterpret its results with this concept. A series of 28 intrauterine cord punctures (between 19 and 33 weeks gestation) with doppler measurements of resistance in umbilical arteries was studied. The theoretical ‘optimal hematocrit’ was well correlated to actual (r  = 0.857, p  < 0.01) but …systematically lower (Bland-Altman plot +12.1[8.52–15.7]) than the actual one. Umbilical artery resistance index is correlated with actual hematocrit (r  = 0.407, p  < 0.05), the discrepancy between ideal and actual (r  = – 0.542, p  < 0.05) but not predicted ideal hematocrit, suggesting that the discrepancy between ideal and actual may reflect an adaptative decrease aiming at reducing vascular resistance. These findings indicate that prediction of ideal hematocrit with Quemada’s equation makes sense in fetal blood, and suggest that a ‘viscoregulatory mechanism’ maintains hematocrit below this theoretical value in order to avoid excess vascular resistance. Show more

Keywords: Blood viscosity, hematocrit, exercise, fetus, erythrocyte deformability

DOI: 10.3233/CH-168016

Citation: Clinical Hemorheology and Microcirculation, vol. 64, no. 4, pp. 789-797, 2016