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Hultman M, Richter F, Larsson M, Strömberg T, Iredahl F, Fredriksson I. Robust analysis of microcirculatory flowmotion during post-occlusive reactive hyperemia. Microvasc Res 2024; 155:104715. [PMID: 39004173 DOI: 10.1016/j.mvr.2024.104715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 07/01/2024] [Accepted: 07/11/2024] [Indexed: 07/16/2024]
Abstract
BACKGROUND Flowmotion analysis of the microcirculatory blood flow is a method to extract information about the vessel regulatory function. It has previously shown promise when applied to measurements during a post-occlusive reactive hyperemia. However, the reperfusion peak and the following monotonic decline introduces false low frequencies that should not be interpreted as rhythmic vasomotion effect. AIM To develop and validate a robust method for flowmotion analysis of post-occlusive reactive hyperemia signals. METHOD The occlusion-induced reperfusion response contains a typical rapid increase followed by a monotonic decline to baseline. A mathematical model is proposed to detrend this transient part of the signal to enable further flowmotion analysis. The model is validated in 96 measurements on healthy volunteers. RESULTS Applying the proposed model corrects the flowmotion signal without adding any substantial new false flowmotion components. CONCLUSION Future studies should use the proposed method or equivalent when analyzing flowmotion during post-occlusive reactive hyperemia to ensure valid results.
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Affiliation(s)
- Martin Hultman
- Department of Biomedical Engineering, Linköping University, Sweden; Perimed AB, Datavägen 9A, Järfälla, Stockholm, Sweden.
| | - Freya Richter
- Primary Health Care Center, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Marcus Larsson
- Department of Biomedical Engineering, Linköping University, Sweden
| | - Tomas Strömberg
- Department of Biomedical Engineering, Linköping University, Sweden
| | - Fredrik Iredahl
- Primary Health Care Center, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Ingemar Fredriksson
- Department of Biomedical Engineering, Linköping University, Sweden; Perimed AB, Datavägen 9A, Järfälla, Stockholm, Sweden
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Wang Q, Zhang X, Li B, Liu X, Li A, Li H, Shi X, Han J. Tumor-Derived Exosomes Promote Tumor Growth Through Modulating Microvascular Hemodynamics in a Human Ovarian Cancer Xenograft Model. Microcirculation 2024:e12876. [PMID: 39005221 DOI: 10.1111/micc.12876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 04/27/2024] [Accepted: 06/29/2024] [Indexed: 07/16/2024]
Abstract
OBJECTIVE Abnormal tumor vascular network contributes to aberrant blood perfusion and reduced oxygenation in tumors, which lead to poor efficacy of chemotherapy and radiotherapy. We aimed to explore the effects of the tumor-derived exosomes (TDEs) and C188-9 (a small molecule inhibitor of signal transducer and activator of transcription 3, STAT3) on tumor microvascular hemodynamics and determine which blood flow oscillations for various frequency intervals are responsible for these changes. METHODS Microvascular hemodynamics parameters were recorded using a PeriFlux 6000 EPOS system in tumor surface in a nude mouse subcutaneous xenograft model. Oscillations of laser Doppler flowmetry (LDF) signal were investigated by wavelet transform analysis. RESULTS TDEs facilitated tumor growth at least partially was associated with increasing blood flow in smaller vessels with lower speed and decreasing the blood flow at larger vessels with higher speed. Lower oxyhemoglobin saturation (SO2) on tumor surface was aggravated by TDEs, and C188-9 treatment significantly alleviated this decrease. Wavelet transform spectral analysis revealed that TDEs increased the amplitude of oscillations in four frequency intervals related to endothelial (NO-dependent and -independent), myogenic and neurogenic activities, and C188-9 had no effect on this increase. CONCLUSIONS TDEs facilitated tumor growth partially was associated with increasing blood flow in distributing vessels, reducing blood perfusion in larger vessels, and lowering SO2 on tumor surface. Enhanced vascular smooth muscle, endothelial and neurogenic activities occurred in tumor superficial zone.
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Affiliation(s)
- Qin Wang
- Institute of Microcirculation, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- International Center of Microvascular Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Xiaoyan Zhang
- Institute of Microcirculation, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- International Center of Microvascular Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Bingwei Li
- Institute of Microcirculation, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- International Center of Microvascular Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Xueting Liu
- Institute of Microcirculation, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- International Center of Microvascular Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Ailing Li
- Institute of Microcirculation, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- International Center of Microvascular Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Hongwei Li
- Institute of Microcirculation, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- International Center of Microvascular Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Xiaohua Shi
- Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, China
| | - Jianqun Han
- Institute of Microcirculation, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- International Center of Microvascular Medicine, Chinese Academy of Medical Sciences, Beijing, China
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Samils L, Henricson J, Strömberg T, Fredriksson I, Iredahl F. Workload and sex effects in comprehensive assessment of cutaneous microcirculation. Microvasc Res 2023; 148:104547. [PMID: 37192688 DOI: 10.1016/j.mvr.2023.104547] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/25/2023] [Accepted: 05/11/2023] [Indexed: 05/18/2023]
Abstract
INTRODUCTION Workload and sex-related differences have been proposed as factors of importance when evaluating the microcirculation. Simultaneous assessments with diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry (LDF) enable a comprehensive evaluation of the microcirculation. The aim of the study was to compare the response between sexes in the microcirculatory parameters red blood cell (RBC) tissue fraction, RBC oxygen saturation, average vessel diameter, and speed-resolved perfusion during baseline, cycling, and recovery, respectively. METHODS In 24 healthy participants (aged 20 to 30 years, 12 females), cutaneous microcirculation was assessed by LDF and DRS at baseline, during a workload generated by cycling at 75 to 80 % of maximal age-predicted heart rate, and recovery, respectively. RESULTS Females had significantly lower RBC tissue fraction and total perfusion in forearm skin microcirculation at all phases (baseline, workload, and recovery). All microvascular parameters increased significantly during cycling, most evident in RBC oxygen saturation (34 % increase on average) and perfusion (9-fold increase in total perfusion). For perfusion, the highest speeds (>10 mm/s) increased by a factor of 31, whereas the lowest speeds (<1 mm/s) increased by a factor of 2. CONCLUSION Compared to a resting state, all studied microcirculation measures increased during cycling. For perfusion, this was mainly due to increased speed, and only to a minor extent due to increased RBC tissue fraction. Skin microcirculatory differences between sexes were seen in RBC concentration and total perfusion.
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Affiliation(s)
- Linda Samils
- Department of Health, Medicine and Caring Sciences, Division of Community Medicine, Linköping University, Linköping, Sweden
| | - Joakim Henricson
- Department of Emergency Medicine in Linköping, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Tomas Strömberg
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Ingemar Fredriksson
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Fredrik Iredahl
- Department of Health, Medicine and Caring Sciences, Division of Community Medicine, Linköping University, Linköping, Sweden.
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Flowmotion imaging analysis of spatiotemporal variations in skin microcirculatory perfusion. Microvasc Res 2023; 146:104456. [PMID: 36403668 DOI: 10.1016/j.mvr.2022.104456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/02/2022] [Accepted: 11/12/2022] [Indexed: 11/19/2022]
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Hultman M, Larsson M, Strömberg T, Fredriksson I. Speed-resolved perfusion imaging using multi-exposure laser speckle contrast imaging and machine learning. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:036007. [PMID: 36950019 PMCID: PMC10027009 DOI: 10.1117/1.jbo.28.3.036007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/27/2023] [Indexed: 05/19/2023]
Abstract
SIGNIFICANCE Laser speckle contrast imaging (LSCI) gives a relative measure of microcirculatory perfusion. However, due to the limited information in single-exposure LSCI, models are inaccurate for skin tissue due to complex effects from e.g. static and dynamic scatterers, multiple Doppler shifts, and the speed-distribution of blood. It has been demonstrated how to account for these effects in laser Doppler flowmetry (LDF) using inverse Monte Carlo (MC) algorithms. This allows for a speed-resolved perfusion measure in absolute units %RBC × mm/s, improving the physiological interpretation of the data. Until now, this has been limited to a single-point LDF technique but recent advances in multi-exposure LSCI (MELSCI) enable the analysis in an imaging modality. AIM To present a method for speed-resolved perfusion imaging in absolute units %RBC × mm/s, computed from multi-exposure speckle contrast images. APPROACH An artificial neural network (ANN) was trained on a large simulated dataset of multi-exposure contrast values and corresponding speed-resolved perfusion. The dataset was generated using MC simulations of photon transport in randomized skin models covering a wide range of physiologically relevant geometrical and optical tissue properties. The ANN was evaluated on in vivo data sets captured during an occlusion provocation. RESULTS Speed-resolved perfusion was estimated in the three speed intervals 0 to 1 mm / s , 1 to 10 mm / s , and > 10 mm / s , with relative errors 9.8%, 12%, and 19%, respectively. The perfusion had a linear response to changes in both blood tissue fraction and blood flow speed and was less affected by tissue properties compared with single-exposure LSCI. The image quality was subjectively higher compared with LSCI, revealing previously unseen macro- and microvascular structures. CONCLUSIONS The ANN, trained on modeled data, calculates speed-resolved perfusion in absolute units from multi-exposure speckle contrast. This method facilitates the physiological interpretation of measurements using MELSCI and may increase the clinical impact of the technique.
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Affiliation(s)
- Martin Hultman
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Perimed AB, Stockholm, Sweden
- Address all correspondence to Martin Hultman,
| | - Marcus Larsson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Tomas Strömberg
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Ingemar Fredriksson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Perimed AB, Stockholm, Sweden
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Salvatori P, Paradisi S, Zani A. Free flaps monitoring by Laser-Doppler Flowmetry in head and neck surgery. ACTA OTORHINOLARYNGOLOGICA ITALICA : ORGANO UFFICIALE DELLA SOCIETA ITALIANA DI OTORINOLARINGOLOGIA E CHIRURGIA CERVICO-FACCIALE 2022; 42:427-433. [PMID: 36541380 PMCID: PMC9793142 DOI: 10.14639/0392-100x-n1956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 07/26/2022] [Indexed: 12/24/2022]
Abstract
Objective Early recognition of free flap vascular impairment is essential for flap salvage attempts. Several methods for surveillance of post-operative flaps are available. Among these, we have extensively used Laser-Doppler Perfusion Flowmetry (LDF) monitoring. We report our experience on this topic and illustrate the advantages and weak points. Methods Over seven years, 110 consecutive free flaps for head and neck reconstruction were monitored using the Periflux System 5000® (Perimed AB, Järfälla, Sweden). In addition to maximum and minimum peaks, a pattern called vasomotion can be detected. Monitoring time lasted from 3 to 7 days, 24/24 h. Results Six of 110 (5.5%) cases of vascular problems were detected and clinically confirmed. In 5 cases, venous thrombosis was present: 4 patients were successfully treated. In 1 case, both arterial and venous thrombosis occurred. Flowmetry data always showed a more or less sudden disappearance of vasomotion. Conclusions LDF is a highly sensible, specific and reliable method. It is easy to use and interpret at low cost. Remote monitoring could also be developed.
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Affiliation(s)
- Pietro Salvatori
- Head & Neck Surgeon (Ret.), Milan, Italy,Correspondence Pietro Salvatori Head & Neck Surgeon (Ret.), via C. Saldini 28, 20133 Milan, Italy E-mail:
| | - Stefano Paradisi
- Department of Otorhinolaryngology, Vimercate Hospital (MB), Italy
| | - Andrea Zani
- Department of Otorhinolaryngology, Portogruaro Hospital (VE), Italy
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Ma KF, Kleiss SF, Schuurmann RCL, Nijboer TS, El Moumni M, Bokkers RPH, de Vries JPPM. Laser Doppler Flowmetry Combined with Spectroscopy to Determine Peripheral Tissue Perfusion and Oxygen Saturation: A Pilot Study in Healthy Volunteers and Patients with Peripheral Arterial Disease. J Pers Med 2022; 12:jpm12060853. [PMID: 35743638 PMCID: PMC9224808 DOI: 10.3390/jpm12060853] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 05/20/2022] [Indexed: 12/27/2022] Open
Abstract
Background: In this study, we assessed the ability of the EPOS system (Perimed AB, Järfälla, Stockholm, Sweden) to detect differences in tissue perfusion between healthy volunteers and patients with peripheral arterial disease (PAD) with different severity of disease. Methods: This single-center prospective pilot study included 10 healthy volunteers and 20 patients with PAD scheduled for endovascular therapy (EVT). EPOS measurements were performed at rest at 32 °C and 44 °C, followed by transcutaneous oxygen pressure (TcPo2) measurements. The measurements were performed on the dorsal and medial side of the foot, as well as the lateral side of the calf. EPOS parameters included hemoglobin oxygen saturation (HbSo2) and speed-resolved red blood cell (RBC) perfusion. Results: HbSo2 at 44 °C was significantly different between the three groups for all measurement locations. The overall speed-resolved RBC perfusion at 44 °C was statistically significant between the groups on the dorsal and medial side of the foot but not on the calf. TcPo2 values were not significantly different between the three groups. Conclusions: This study demonstrates that the EPOS system can depict differences in tissue perfusion between healthy volunteers, patients with Fontaine class IIb PAD, and those with Fontaine class III or IV PAD but only after heating to 44 °C.
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Affiliation(s)
- Kirsten F. Ma
- Division of Vascular Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands; (S.F.K.); (R.C.L.S.); (T.S.N.); (J.-P.P.M.d.V.)
- Correspondence:
| | - Simone F. Kleiss
- Division of Vascular Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands; (S.F.K.); (R.C.L.S.); (T.S.N.); (J.-P.P.M.d.V.)
| | - Richte C. L. Schuurmann
- Division of Vascular Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands; (S.F.K.); (R.C.L.S.); (T.S.N.); (J.-P.P.M.d.V.)
| | - Thomas S. Nijboer
- Division of Vascular Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands; (S.F.K.); (R.C.L.S.); (T.S.N.); (J.-P.P.M.d.V.)
| | - Mostafa El Moumni
- Division of Trauma Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands;
| | - Reinoud P. H. Bokkers
- Department of Radiology, Medical Imaging Center, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands;
| | - Jean-Paul P. M. de Vries
- Division of Vascular Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands; (S.F.K.); (R.C.L.S.); (T.S.N.); (J.-P.P.M.d.V.)
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Liu S, Zhao L, Liu Y. The Origin of Vasomotion and Stochastic Resonance in Vasomotion. Front Bioeng Biotechnol 2022; 10:819716. [PMID: 35309989 PMCID: PMC8924506 DOI: 10.3389/fbioe.2022.819716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 01/14/2022] [Indexed: 11/13/2022] Open
Abstract
Vasomotion is the spontaneous time-dependent contraction and relaxation of micro arteries and the oscillating frequency is about 0.01–0.1 Hz. The physiological mechanism of vasomotion has not been thoroughly understood. From the dynamics point of view, the heartbeat is the only external loading exerted on the vascular system. We speculate that the nonlinear vascular system and the variable period of the heartbeat might induce the low-frequency vasomotion. In this study, the laser Doppler flowmeter is used to measure the time series of radial artery blood flow and reconstructed modified time series that has the same period as the measured time series but different heartbeat curves. We measured the time series of radial artery blood flow in different conditions by adding different noise disturbances on the forearm, and we decomposed the experiment pulse signal by Hilbert–Huang transform. The wavelet spectral analyses showed that the low-frequency components were induced by the variable period but independent of the shape of the heartbeat curve. Furthermore, we simulated the linear flow in a single pipe and the nonlinear flow in a piping network and found that the nonlinear flow would generate low-frequency components. From the results, we could deduce that the variable period of heartbeat and the nonlinearity of the vascular system induce vasomotion. The noise has effects on the blood signals related to the respiratory activities (∼0.3 Hz) but little influence on that related to the cardiac activities (∼1 Hz). Adding white noise and then stopping would induce an SNR increase in the frequency band related to vasomotion (∼0.1 Hz).
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Affiliation(s)
- Shuhong Liu
- Research Centre for Fluid-Structure Interactions, Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Liangjing Zhao
- Research Centre for Fluid-Structure Interactions, Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Yang Liu
- Department of Mechanical Engineering, Kowloon, Hong Kong SAR, China
- *Correspondence: Yang Liu,
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