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Long Z, Hangiandreou NJ, Macedo TA, Tradup DJ, Hesley GK. Technical Note: Impact of Linear Array Transducer Doppler Aperture Location on Spectral Peak Velocity Measurements - A Phantom Study. ULTRASOUND IN MEDICINE & BIOLOGY 2024; 50:1479-1483. [PMID: 38849280 DOI: 10.1016/j.ultrasmedbio.2024.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/13/2024] [Accepted: 05/15/2024] [Indexed: 06/09/2024]
Abstract
OBJECTIVE Ultrasound beams sometimes need to be steered from the edge of linear array transducers to reach the sample volume with a desired Doppler angle in vascular exams. This phantom study aims to evaluate the impact of apertures located at the array edge on peak velocity (PV) measurements. METHODS Three ultrasound scanner systems equipped with eight transducers from 3 major ultrasound vendors were tested using a flow phantom with a horizontal tube. Five spectral Doppler measurements with the aperture positioned at one edge of the array and 5 with the aperture at the center of the array were obtained using all available scanner-transducer combinations while maintaining all scan parameters and the sample volume in the same tube location. Differences in PVs between center and edge apertures were compared across 4 constant flow rates. RESULTS The averaged PVs for all phantom flow rates ranged from 24.4 cm/s to 138.2 cm/s from the array center. The averaged PVs from the center aperture were significantly greater than the corresponding measurements from the edge aperture for each flow rate (all p < 0.001). The relative PV differences ranged from 6.7% to 19.4% across all transducers and flow rates. CONCLUSION Significantly lower PVs were consistently shown with the Doppler beam aperture at the array edge compared to center among all tested systems. This may be due to a narrower aperture width, shifted central axis, and less intrinsic spectral broadening error at the array edge. Controlling variations in Doppler aperture location is important in clinical applications which depend on consistent velocity measurements.
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Affiliation(s)
- Zaiyang Long
- Department of Radiology, Mayo Clinic, Rochester, MN, USA.
| | | | - Thanila A Macedo
- Department of Radiology, UT Health, McGovern Medical School, Houston, TX, USA
| | | | - Gina K Hesley
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
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2
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Russ MK, Lafata NM, Robertson SH, Samei E. Pulsed wave Doppler ultrasound: Accuracy, variability, and impact of acquisition parameters on flow measurements. Med Phys 2023; 50:6704-6713. [PMID: 37793117 DOI: 10.1002/mp.16774] [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: 01/23/2023] [Revised: 08/22/2023] [Accepted: 09/15/2023] [Indexed: 10/06/2023] Open
Abstract
BACKGROUND Pulsed wave Doppler ultrasound is a useful modality for assessing vascular health as it quantifies blood flow characteristics. To facilitate accurate diagnosis, accuracy and consistency of this modality should be assessed through Doppler quality assurance (QA). PURPOSE The purpose of this study was to characterize the accuracy, reproducibility, and inter-scanner variability of ultrasound flow velocity measurements via a flow phantom, with a focus on the effect of systematic acquisition parameters on measured flow velocity accuracy. METHODS Using a manufacturer-calibrated flow phantom, pulsed wave measurements were acquired on five clinical systems (iU22, Philips) with three models of transducers, including both linear and curvilinear models. The peak and mean flow velocities were estimated by vendor-supplied spectral analysis tools. To investigate intra- and inter-scanner variability, measurements were repeated using each scanner-transducer pair under a standardized set of conditions. Inter-scanner variability was assessed using ANOVA. Flow velocity accuracy was investigated by mean absolute percentage error. The impacts of receive gain, measurement depth, and beam steering on measured flow velocity accuracy were examined by varying each parameter over its available range and comparing to the ground truth flow velocity. RESULTS Inter-scanner variability was statistically significant for peak flow measurements made using both linear and curvilinear transducers, though absolute differences in measured velocity were small. Inter-scanner variability was not statistically significant for mean flow velocity. Receive gain, measurement depth, and beam steering were all found to impact the accuracy of measured flow characteristics for linear transducers. Accuracy of the flow measurements made with the curvilinear transducer demonstrated high consistency to changes in receive gain at a constant depth, though were impacted by increasing the measurement depth. CONCLUSIONS Carefully and consistently selected acquisition and set-up parameters are essential in order to establish a reliable and meaningful QA program.
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Affiliation(s)
- Megan K Russ
- Clinical Imaging Physics Group, Duke University Health System, Durham, North Carolina, USA
- Department of Radiology, Duke University, Durham, North Carolina, USA
| | - Nicole M Lafata
- Clinical Imaging Physics Group, Duke University Health System, Durham, North Carolina, USA
- Department of Radiology, Duke University, Durham, North Carolina, USA
| | - Scott H Robertson
- Clinical Imaging Physics Group, Duke University Health System, Durham, North Carolina, USA
- Department of Radiology, Duke University, Durham, North Carolina, USA
| | - Ehsan Samei
- Clinical Imaging Physics Group, Duke University Health System, Durham, North Carolina, USA
- Department of Radiology, Duke University, Durham, North Carolina, USA
- Center for Virtual Imaging Trials, Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University, Durham, North Carolina, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina, USA
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van Amerom JFP, Goolaub DS, Schrauben EM, Sun L, Macgowan CK, Seed M. Fetal cardiovascular blood flow MRI: techniques and applications. Br J Radiol 2023; 96:20211096. [PMID: 35687661 PMCID: PMC10321246 DOI: 10.1259/bjr.20211096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 05/11/2022] [Accepted: 05/24/2022] [Indexed: 11/05/2022] Open
Abstract
Fetal cardiac MRI is challenging due to fetal and maternal movements as well as the need for a reliable cardiac gating signal and high spatiotemporal resolution. Ongoing research and recent technical developments to address these challenges show the potential of MRI as an adjunct to ultrasound for the assessment of the fetal heart and great vessels. MRI measurements of blood flow have enabled the assessment of normal fetal circulation as well as conditions with disrupted circulations, such as congenital heart disease, along with associated organ underdevelopment and hemodynamic instability. This review provides details of the techniques used in fetal cardiovascular blood flow MRI, including single slice and volumetric imaging sequences, post-processing and analysis, along with a summary of applications in human studies and animal models.
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Affiliation(s)
- Joshua FP van Amerom
- Division of Translational Medicine, SickKids Research Institute, Toronto, Canada
| | | | - Eric M Schrauben
- Department of Radiology & Nuclear Medicine, Amsterdam University Medical Centers, Amsterdam, Netherlands
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Hasegawa H, Omura M, Nagaoka R, Saito K. Two-Dimensional Wavenumber Analysis Implemented in Ultrasonic Vector Doppler Method with Focused Transmit Beams. SENSORS (BASEL, SWITZERLAND) 2022; 22:9787. [PMID: 36560161 PMCID: PMC9781179 DOI: 10.3390/s22249787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/05/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
The multi-angle Doppler method was introduced for the estimation of velocity vectors by measuring axial velocities from multiple directions. We have recently reported that the autocorrelation-based velocity vector estimation could be ameliorated significantly by estimating the wavenumbers in two dimensions. Since two-dimensional wavenumber estimation requires a snapshot of an ultrasonic field, the method was first implemented in plane wave imaging. Although plane wave imaging is predominantly useful for examining blood flows at an extremely high temporal resolution, it was reported that the contrast in a B-mode image obtained with a few plane wave emissions was lower than that obtained with focused beams. In this study, the two-dimensional wavenumber analysis was first implemented in a framework with focused transmit beams. The simulations showed that the proposed method achieved an accuracy in velocity estimation comparable to that of the method with plane wave imaging. Furthermore, the performances of the methods implemented in focused beam and plane wave imaging were compared by measuring human common carotid arteries in vivo. Image contrasts were analyzed in normal and clutter-filtered B-mode images. The method with focused beam imaging achieved a better contrast in normal B-mode imaging, and similar velocity magnitudes and angles were obtained by both the methods with focused beam and plane wave imaging. In contrast, the method with plane wave imaging gave a better contrast in a clutter-filtered B-mode image and smaller variances in velocity magnitudes than those with focused beams.
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Affiliation(s)
- Hideyuki Hasegawa
- Faculty of Engineering, University of Toyama, Toyama 930-8555, Japan
| | - Masaaki Omura
- Faculty of Engineering, University of Toyama, Toyama 930-8555, Japan
| | - Ryo Nagaoka
- Faculty of Engineering, University of Toyama, Toyama 930-8555, Japan
| | - Kozue Saito
- Department of Neurology, Stroke Center, Nara Medical University, Nara 634-8522, Japan
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Nouh MAEL, Abd-Elmageed MK, Amer AAM, ELhamouly MS. Role of portal color Doppler ultrasonography as noninvasive predictive tool for esophageal varices in cirrhotic patients. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2022. [DOI: 10.1186/s43055-021-00681-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Esophageal varices (EV) is the most common apprehensive complication of portal hypertension in patients with cirrhotic liver. Guidelines recommend Upper gastro-intestinal endoscopic screening for EV in patients with newly diagnosed chronic cirrhosis (Imperiale et al. in Hepatology 45(4):870–878, 2007). Yet, it is invasive, time consuming and costly. To avoid unnecessary endoscopy, some studies have suggested Doppler ultrasound examination as simple, and noninvasive tool in prediction and assessment of severity of EV (Agha et al. in Dig Dis Sci 54(3):654–660, 2009). Our study was to assess the role of different Doppler indices of portal vein, hepatic and splenic arteries as a noninvasive tool for prediction of esophageal varices in cirrhotic patients.
Results
This prospective case control study was conducted on 100 cirrhotic liver patients and 100 of healthy volunteers as control group. Patients were subjected to clinical examination, upper gastrointestinal tract endoscopy, abdominal ultrasonography with duplex Doppler evaluation of different portal Doppler hemodynamic indices were done for each patient. The results revealed that portal vein diameter, hepatic artery pulsatility index, portal hypertensive index, portal vein flow velocity, portal congestion index have high sensitivity for prediction of EV. However, Splenic artery resistance index, hepatic artery resistance index HARI, liver vascular index and platelet count/spleen diameter have less sensitivity for prediction of EV.
Conclusion
Measuring the portal hemodynamic indices can help physicians as noninvasive predictors of EV in cirrhotic patients to restrict the need for unnecessary endoscopic screening especially when endoscopic facilities are limited.
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Furdella KJ, Higuchi S, Kim K, Doetschman T, Wagner WR, Vande Geest JP. ACUTE ELUTION OF TGFβ2 AFFECTS THE SMOOTH MUSCLE CELLS IN A COMPLIANCE-MATCHED VASCULAR GRAFT. Tissue Eng Part A 2022; 28:640-650. [PMID: 35521649 DOI: 10.1089/ten.tea.2021.0161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Transforming growth factor beta 2 (TGFβ2) is a pleiotropic growth factor that plays a vital role in smooth muscle cell (SMC) function. Our prior in vitro work has shown that SMC response can be modulated with TGFβ2 stimulation in a dose dependent manner. In particular, we have shown that increasing concentrations of TGFβ2 shift SMCs from a migratory to a synthetic behavior. In this work, electrospun compliance-matched and hypocompliant TGFβ2-eluting TEVGs were implanted into Sprague Dawley rats for 5 days to observe SMC population and collagen production. TEVGs were fabricated using a combined computational and experimental approach that varied the ratio of gelatin:polycaprolactone to be either compliance-matched or twice as stiff as rat aorta (hypocompliant). TGFβ2 concentrations of 0, 10, 100 ng/mg were added to both graft types (n=3 in each group) and imaged in vivo using ultrasound. Histological markers (SMC, macrophage, collagen, and elastin) were evaluated following explantation at 5 days. In vivo ultrasound showed that compliance-matched TEVGs became stiffer as TGFβ2 increased (100 ng/mg TEVGS compared to rat aorta, p<0.01) while all hypocompliant grafts remained stiffer than control rat aorta. In vivo velocity and diameter were also not significantly different than control vessels. The compliance-matched 10 ng/mg group had an elevated SMC signal (myosin heavy chain) compared to the 0 and 100 ng/mg grafts (p=0.0009 & 0.0006 ). Compliance-matched TEVGs containing 100 ng/mg TGFβ2 had an increase in collagen production (p<0.01), general immune response (p<0.05), and a decrease in SMC population to the 0 and 10 ng/mg groups. All hypocompliant groups were found to be similar, suggesting a lower rate of TGFβ2 release in these TEVGs. Our results suggest that TGFβ2 can modulate in vivo SMC phenotype over an acute implantation period, which is consistent with our prior in vitro work. To the author's knowledge, this is first in vivo rat study that evaluates a TGFβ2-eluting TEVG.
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Affiliation(s)
- Kenneth John Furdella
- University of Pittsburgh Swanson School of Engineering, 110071, Bioengineering, Pittsburgh, Pennsylvania, United States;
| | - Shinichi Higuchi
- University of Pittsburgh Swanson School of Engineering, 110071, McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania, United States;
| | - Kang Kim
- University of Pittsburgh Swanson School of Engineering, 110071, Department of Bioengineering, Pittsburgh, Pennsylvania, United States;
| | - Tom Doetschman
- University of Arizona Biochemistry and Molecular and Cellular Biology program, 242717, Tucson, Arizona, United States;
| | - William R Wagner
- University of Pittsburgh, 6614, McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania, United States;
| | - Jonathan P Vande Geest
- University of Pittsburgh Swanson School of Engineering, 110071, Bioengineering, Pittsburgh, Pennsylvania, United States;
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Ødegård SS, Torp H, Follestad T, Leth-Olsen M, Støen R, Nyrnes SA. Low frequency cerebral arterial and venous flow oscillations in healthy neonates measured by NeoDoppler. Front Pediatr 2022; 10:929117. [PMID: 36518773 PMCID: PMC9742353 DOI: 10.3389/fped.2022.929117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 11/09/2022] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND A cerebroprotective effect of low frequency oscillations (LFO) in cerebral blood flow (CBF) has been suggested in adults, but its significance in neonates is not known. This observational study evaluates normal arterial and venous cerebral blood flow in healthy neonates using NeoDoppler, a novel Doppler ultrasound system which can measure cerebral hemodynamics continuously. METHOD Ultrasound Doppler data was collected for 2 h on the first and second day of life in 36 healthy term born neonates. LFO (0.04-0.15 Hz) were extracted from the velocity curve by a bandpass filter. An angle independent LFO index was calculated as the coefficient of variation of the filtered curve. Separate analyses were done for arterial and venous signals, and results were related to postnatal age and behavioral state (asleep or awake). RESULTS The paper describes normal physiologic variations of arterial and venous cerebral hemodynamics. Mean (SD) arterial and venous LFO indices (%) were 6.52 (2.55) and 3.91 (2.54) on day one, and 5.60 (1.86) and 3.32 (2.03) on day two. After adjusting for possible confounding factors, the arterial LFO index was estimated to decrease by 0.92 percent points per postnatal day (p < 0.001). The venous LFO index did not change significantly with postnatal age (p = 0.539). Arterial and venous LFO were not notably influenced by behavioral state. CONCLUSION The results indicate that arterial LFO decrease during the first 2 days of life in healthy neonates. This decrease most likely represents normal physiological changes related to the transitional period. A similar decrease for venous LFO was not found.
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Affiliation(s)
- Siv Steinsmo Ødegård
- Department of Circulation and Medical Imaging (ISB), The Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Children's Clinic, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Hans Torp
- Department of Circulation and Medical Imaging (ISB), The Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Turid Follestad
- Department of Clinical and Molecular Medicine (IKOM), The Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Martin Leth-Olsen
- Department of Circulation and Medical Imaging (ISB), The Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Children's Clinic, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Ragnhild Støen
- Children's Clinic, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.,Department of Clinical and Molecular Medicine (IKOM), The Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Siri Ann Nyrnes
- Department of Circulation and Medical Imaging (ISB), The Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Children's Clinic, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
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Brandt AH, Olesen JB, Moshavegh R, Jensen JA, Nielsen MB, Hansen KL. Common Carotid Artery Volume Flow: A Comparison Study between Ultrasound Vector Flow Imaging and Phase Contrast Magnetic Resonance Imaging. Neurol Int 2021; 13:269-278. [PMID: 34201493 PMCID: PMC8293467 DOI: 10.3390/neurolint13030028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/19/2021] [Accepted: 06/20/2021] [Indexed: 11/16/2022] Open
Abstract
Volume flow estimation in the common carotid artery (CCA) can assess the absolute hemodynamic effect of a carotid stenosis. The aim of this study was to compare a commercial vector flow imaging (VFI) setup against the reference method magnetic resonance phase contrast angiography (MRA) for volume flow estimation in the CCA. Ten healthy volunteers were scanned with VFI and MRA over the CCA. VFI had an improved precision of 19.2% compared to MRA of 31.9% (p = 0.061). VFI estimated significantly lower volume flow than MRA (mean difference: 63.2 mL/min, p = 0.017), whilst the correlation between VFI and MRA was strong (R2 = 0.81, p < 0.0001). A Bland–Altman plot indicated a systematic bias. After bias correction, the percentage error was reduced from 41.0% to 25.2%. This study indicated that a VFI setup for volume flow estimation is precise and strongly correlated to MRA volume flow estimation, and after correcting for the systematic bias, VFI and MRA become interchangeable.
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Affiliation(s)
- Andreas Hjelm Brandt
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen University Hospital, 2100 Copenhagen, Denmark; (M.B.N.); (K.L.H.)
- Correspondence:
| | | | | | - Jørgen Arendt Jensen
- Center for Fast Ultrasound Imaging, Department of Health Technology, Technical University of Denmark, 2800 Lyngby, Denmark;
| | - Michael Bachmann Nielsen
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen University Hospital, 2100 Copenhagen, Denmark; (M.B.N.); (K.L.H.)
- Department of Clinical Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Kristoffer Lindskov Hansen
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen University Hospital, 2100 Copenhagen, Denmark; (M.B.N.); (K.L.H.)
- Department of Clinical Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
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Wang Y, Lee WN. Non-Invasive Estimation of Localized Dynamic Luminal Pressure Change by Ultrasound Elastography in Arteries With Normal and Abnormal Geometries. IEEE Trans Biomed Eng 2021; 68:1627-1637. [DOI: 10.1109/tbme.2020.3028186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Furdella KJ, Higuchi S, Behrangzade A, Kim K, Wagner WR, Vande Geest JP. In-vivo assessment of a tissue engineered vascular graft computationally optimized for target vessel compliance. Acta Biomater 2021; 123:298-311. [PMID: 33482362 DOI: 10.1016/j.actbio.2020.12.058] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 12/22/2020] [Accepted: 12/29/2020] [Indexed: 11/24/2022]
Abstract
Tissue engineered vascular grafts (TEVGs) have the ability to be tuned to match a target vessel's compliance, diameter, wall thickness, and thereby prevent compliance mismatch. In this work, TEVG compliance was manipulated by computationally tuning its layered composition or by manipulating a crosslinking agent (genipin). In particular, these three acelluluar TEVGs were compared: a compliance matched graft (CMgel - high gelatin content); a hypocompliant PCL graft (HYPOpcl - high polycaprolactone content); and a hypocompliant genipin graft (HYPOgen - equivalent composition as CMgel but hypocompliant via increased genipin crosslinking). All constructs were implanted interpositionally into the abdominal aorta of 21 Sprague Dawley rats (n=7, males=11, females=10) for 28 days, imaged in-vivo using ultrasound, explanted, and assessed for remodeling using immunofluorescence and two photon excitation fluorescence imaging. Compliance matched grafts remained compliance-matched in-vivo compared to the hypocompliant grafts through 4 weeks (p<0.05). Construct degradation and cellular infiltration was increased in the CMgel and HYPOgen TEVGs. Contractile smooth muscle cell markers in the proximal anastomosis of the graft were increased in the CMgel group compared to the HYPOpcl (p=0.007) and HYPOgen grafts (p=0.04). Both hypocompliant grafts also had an increased pro-inflammatory response (increased ratio of CD163 to CD86 in the mid-axial location) compared to the CMgel group. Our results suggest that compliance matching using a computational optimization approach leads to the improved acute (28 day) remodeling of TEVGs. To the authors' knowledge, this is the first in-vivo rat study investigating TEVGs that have been computationally optimized for target vessel compliance.
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Hoving AM, Voorneveld J, Mikhal J, Bosch JG, Groot Jebbink E, Slump CH. In vitro performance of echoPIV for assessment of laminar flow profiles in a carotid artery stent. J Med Imaging (Bellingham) 2021; 8:017001. [PMID: 33457445 PMCID: PMC7804295 DOI: 10.1117/1.jmi.8.1.017001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 12/22/2020] [Indexed: 11/14/2022] Open
Abstract
Purpose: Detailed blood flow studies may contribute to improvements in carotid artery stenting. High-frame-rate contrast-enhanced ultrasound followed by particle image velocimetry (PIV), also called echoPIV, is a technique to study blood flow patterns in detail. The performance of echoPIV in presence of a stent has not yet been studied extensively. We compared the performance of echoPIV in stented and nonstented regions in an in vitro flow setup. Approach: A carotid artery stent was deployed in a vessel-mimicking phantom. High-frame-rate contrast-enhanced ultrasound images were acquired with various settings. Signal intensities of the contrast agent, velocity values, and flow profiles were calculated. Results: The results showed decreased signal intensities and correlation coefficients inside the stent, however, PIV analysis in the stent still resulted in plausible flow vectors. Conclusions: Velocity values and laminar flow profiles can be measured in vitro in stented arteries using echoPIV.
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Affiliation(s)
- Astrid M Hoving
- University of Twente, TechMed Centre, Robotics and Mechatronics Group, Enschede, The Netherlands
| | - Jason Voorneveld
- Erasmus MC, Thorax Center, Department of Biomedical Engineering, Rotterdam, The Netherlands
| | - Julia Mikhal
- University of Twente, TechMed Centre, BIOS Lab-on-a-Chip Group, Enschede, The Netherlands
| | - Johan G Bosch
- Erasmus MC, Thorax Center, Department of Biomedical Engineering, Rotterdam, The Netherlands
| | - Erik Groot Jebbink
- University of Twente, TechMed Centre, Multi-Modality Medical Imaging Group, Enschede, The Netherlands
| | - Cornelis H Slump
- University of Twente, TechMed Centre, Robotics and Mechatronics Group, Enschede, The Netherlands
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Nguyen TQ, Traberg MS, Olesen JB, Heerwagen ST, Brandt AH, Bechsgaard T, Pedersen BL, Moshavegh R, Lönn L, Jensen JA, Nielsen MB, Hansen KL. Flow Complexity Estimation in Dysfunctional Arteriovenous Dialysis Fistulas using Vector Flow Imaging. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:2493-2504. [PMID: 32595057 DOI: 10.1016/j.ultrasmedbio.2020.05.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 05/25/2020] [Accepted: 05/31/2020] [Indexed: 06/11/2023]
Abstract
Non-invasive assessment is preferred for monitoring arteriovenous dialysis fistulas (AVFs). Vector concentration assesses flow complexity, which may correlate with stenosis severity. We determined whether vector concentration could assess stenosis severity in dysfunctional AVFs. Vector concentration was estimated in four stenotic phantoms at different pulse repetition frequencies. Spectral Doppler peak velocity and vector concentration were measured in 12 patients with dysfunctional AVFs. Additionally, 5 patients underwent digital subtraction angiography (DSA). In phantoms, vector concentration exhibited an inverse relationship with stenosis severity and was less affected by aliasing in severe stenoses. In nine stenoses of 5 patients undergoing DSA, vector concentration correlated strongly with stenosis severity (first stenosis: r = -0.73, p = 0.04; other stenoses; r = -0.69, p = 0.02) and mid-stenotic diameter (first stenosis: r = 0.87, p = 0.006; other stenoses: r = 0.70, p = 0.02) as opposed to peak velocities (p > 0.05). Vector concentration is less affected by aliasing in severe stenoses and correlates with DSA in patients with dysfunctional AVF.
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Affiliation(s)
- Tin-Quoc Nguyen
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
| | - Marie Sand Traberg
- Center for Fast Ultrasound Imaging, Department of Health Technology, Technical University of Denmark, Lyngby, Denmark
| | - Jacob Bjerring Olesen
- Center for Fast Ultrasound Imaging, Department of Health Technology, Technical University of Denmark, Lyngby, Denmark; BK Medical, Herlev, Denmark
| | | | | | - Thor Bechsgaard
- Department of Radiology, Odense University Hospital, Odense C, Denmark
| | | | - Ramin Moshavegh
- Center for Fast Ultrasound Imaging, Department of Health Technology, Technical University of Denmark, Lyngby, Denmark; BK Medical, Herlev, Denmark
| | - Lars Lönn
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen Arendt Jensen
- Center for Fast Ultrasound Imaging, Department of Health Technology, Technical University of Denmark, Lyngby, Denmark
| | - Michael Bachmann Nielsen
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Kristoffer Lindskov Hansen
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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13
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Huang H, Chen PY, Huang CC. 40-MHz high-frequency vector Doppler imaging for superficial venous valve flow estimation. Med Phys 2020; 47:4020-4031. [PMID: 32609885 DOI: 10.1002/mp.14362] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/26/2020] [Accepted: 06/17/2020] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Doppler ultrasound imaging has been used widely for diagnosing vascular diseases. Recently, vector Doppler imaging (VDI) has been proposed for visualizing the blood flow in all directions to yield more detailed information for estimating flow conditions. Increasing the resolution of VDI is important for the structural mapping of superficial vessels with microstructure. However, VDI that operates under a high-frequency ultrasound (HFUS; >30 MHz) is rare. In this study, a 40-MHz high-frequency VDI (HFVDI) based on ultrafast ultrasound imaging was developed to obtain the vector information of blood flow around the superficial venous valve. METHODS The use of HFUS imaging system causes an overload of data acquisition easily. In order to provide sufficient recording time, the frame rate should be reduced. Because the aliasing problem worsens due to a low frame rate when operating Doppler imaging, phase-unwrapping processing methods based on spatial and temporal continuities were applied. Flow phantom experiments were performed to validate the accuracy. In vivo experiments were performed on the valve of superficial veins of healthy volunteers. RESULTS The experimental results from the phantom study indicated that the error of velocity estimation was <10% in most cases. Dynamic changes of valve movements and flow conditions (including velocity profiles and vector) were observed. Because of the high resolution of HFVDI, the jet and vortex phenomena were observed between the leaflets and in the sinus pocket, respectively. CONCLUSIONS Flow velocities ranging from 2 to 15 mm/s were measured at different locations around the venous valve during the opening and closing phases. All the results indicated that HFVDI has the potential to be a useful tool for vessel duplex scanning.
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Affiliation(s)
- Hsin Huang
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Pei-Yu Chen
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Chih-Chung Huang
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan.,Medical Device Innovation Center, National Cheng Kung University, Tainan, Taiwan
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14
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Brandt AH, Nguyen TQ, Gutte H, Frederik Carlsen J, Moshavegh R, Jensen JA, Bachmann Nielsen M, Hansen KL. Carotid Stenosis Assessment with Vector Concentration before and after Stenting. Diagnostics (Basel) 2020; 10:E420. [PMID: 32575759 PMCID: PMC7345475 DOI: 10.3390/diagnostics10060420] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/08/2020] [Accepted: 06/18/2020] [Indexed: 11/16/2022] Open
Abstract
Digital subtraction angiography (DSA) is considered the reference method for the assessment of carotid artery stenosis; however, the procedure is invasive and accompanied by ionizing radiation. Velocity estimation with duplex ultrasound (DUS) is widely used for carotid artery stenosis assessment since no radiation or intravenous contrast is required; however, the method is angle-dependent. Vector concentration (VC) is a parameter for flow complexity assessment derived from the angle independent ultrasound method vector flow imaging (VFI), and VC has shown to correlate strongly with stenosis degree. The aim of this study was to compare VC estimates and DUS estimated peak-systolic (PSV) and end-diastolic velocities (EDV) for carotid artery stenosis patients, with the stenosis degree obtained with DSA. Eleven patients with symptomatic carotid artery stenosis were examined with DUS, VFI, and DSA before and after stent treatment. Compared to DSA, VC showed a strong correlation (r = -0.79, p < 0.001), while PSV (r = 0.68, p = 0.002) and EDV (r = 0.51, p = 0.048) obtained with DUS showed a moderate correlation. VFI using VC calculations may be a useful ultrasound method for carotid artery stenosis and stent patency assessment.
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Affiliation(s)
- Andreas Hjelm Brandt
- Department of Radiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (T.-Q.N.); (H.G.); (J.F.C.); (M.B.N.); (K.L.H.)
| | - Tin-Quoc Nguyen
- Department of Radiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (T.-Q.N.); (H.G.); (J.F.C.); (M.B.N.); (K.L.H.)
- Department of Clinical Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Henrik Gutte
- Department of Radiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (T.-Q.N.); (H.G.); (J.F.C.); (M.B.N.); (K.L.H.)
| | - Jonathan Frederik Carlsen
- Department of Radiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (T.-Q.N.); (H.G.); (J.F.C.); (M.B.N.); (K.L.H.)
| | | | - Jørgen Arendt Jensen
- Center for Fast Ultrasound Imaging, Department of Health Technology, Technical University of Denmark, 2800 Lyngby, Denmark;
| | - Michael Bachmann Nielsen
- Department of Radiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (T.-Q.N.); (H.G.); (J.F.C.); (M.B.N.); (K.L.H.)
- Department of Clinical Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Kristoffer Lindskov Hansen
- Department of Radiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark; (T.-Q.N.); (H.G.); (J.F.C.); (M.B.N.); (K.L.H.)
- Department of Clinical Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
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15
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Computational hemodynamics in arteries with the one-dimensional augmented fluid-structure interaction system: viscoelastic parameters estimation and comparison with in-vivo data. J Biomech 2019; 100:109595. [PMID: 31911051 DOI: 10.1016/j.jbiomech.2019.109595] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 12/19/2019] [Accepted: 12/21/2019] [Indexed: 12/21/2022]
Abstract
Mathematical models are widely recognized as a valuable tool for cardiovascular diagnosis and the study of circulatory diseases, especially to obtain data that require otherwise invasive measurements. To correctly simulate body hemodynamics, the viscoelastic properties of vessels walls are a key aspect to be taken into account as they play an essential role in cardiovascular behavior. The present work aims to apply the augmented fluid-structure interaction system of blood flow to real case studies to assess the validity of the model as a valuable resource to improve cardiovascular diagnostics and the treatment of pathologies. Main contributions of the paper include the evaluation of viscoelastic tube laws, estimation of viscoelastic parameters and comparison of models with literature results and in-vivo experiments. The ability of the model to correctly simulate pulse waveforms in single arterial segments is verified using literature benchmark test cases, designed taking into account a simple elastic behavior of the wall in the upper thoracic aorta and in the common carotid artery. Furthermore, in-vivo pressure waveforms, extracted from tonometric measurements performed on four human common carotid arteries and two common femoral arteries, are compared to numerical solutions. It is highlighted that the viscoelastic damping effect of arterial walls is required to avoid an overestimation of pressure peaks. Finally, an effective procedure to estimate the viscoelastic parameters of the model is herein proposed, which returns hysteresis curves of the common carotid arteries dissipating energy fractions in line with values calculated from literature hysteresis loops in the same vessel.
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Walker AR, Uejima T, Prinz C, Voigt JU, Fraser AG. Inaccuracies in Measuring Velocities and Timing of Flow and Tissue Motion Using High-End Ultrasound Systems. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:1446-1454. [PMID: 30975534 DOI: 10.1016/j.ultrasmedbio.2019.02.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 02/03/2019] [Accepted: 02/11/2019] [Indexed: 06/09/2023]
Abstract
To evaluate the accuracy of measurements of the velocities and timing of blood flow and of tissue motion, we tested four commercially available ultrasound systems. Pulsed wave, continuous wave and tissue Doppler recordings acquired across a range of angles of insonation were compared against a calibrated Doppler string phantom. Temporal delays were measured from the onset of the simulated electrocardiogram to the start of each Doppler signal. Across all modalities and angles, the mean errors of measurements of velocity using the four systems were 0.2%, 1.7%, 6.0% and 3.1%. The largest errors occurred using tissue Doppler at 5 cm/s (mean overestimation: 5.8%, range: +1.1%-12.5%). Mean delays in displaying the onset of flow were -3, 6, 11 and -16 ms. All differences between machines were statistically significant. The accuracy of high-end ultrasound systems for measuring velocities is better than in earlier reports, but the reporting of routine testing against standard phantoms should be mandatory.
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Affiliation(s)
- Andrew R Walker
- Department of Biomedical Engineering, Västmanland Hospital, Västerås, Sweden.
| | - Tokuhisa Uejima
- Wales Heart Research Institute, School of Medicine, Cardiff University, Heath Park, Cardiff, United Kingdom
| | - Christian Prinz
- Department of Cardiovascular Diseases, University of Leuven, University Hospital Gasthuisberg, Leuven, Belgium
| | - Jens-Uwe Voigt
- Department of Cardiovascular Diseases, University of Leuven, University Hospital Gasthuisberg, Leuven, Belgium
| | - Alan G Fraser
- Wales Heart Research Institute, School of Medicine, Cardiff University, Heath Park, Cardiff, United Kingdom; Department of Cardiovascular Diseases, University of Leuven, University Hospital Gasthuisberg, Leuven, Belgium
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17
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Radparvar JR, Lim G, Chiem AT. Effect of insonation angle on peak systolic velocity variation. Am J Emerg Med 2019; 38:173-177. [PMID: 30718117 DOI: 10.1016/j.ajem.2019.01.050] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 12/19/2018] [Accepted: 01/28/2019] [Indexed: 10/27/2022] Open
Abstract
OBJECTIVES As point of care ultrasound (POCUS) has become more integrated into emergency and critical care medicine, there has been increased interest in utilizing ultrasound to assess volume status. However, recent studies of carotid POCUS on volume status and fluid responsiveness fail to recognize the effect insonation angle has on their results. To address this, we studied the effect of insonation angle on peak systolic velocity (PSV) change associated with respiratory variation (RV) and passive leg raise (PLR). METHODS Doppler measurements were obtained from 51 subjects presenting to the ED. Minimal and maximal PSV were obtained using insonation angles of 46°, 60°, and 90°. ∆PSV was calculated using PLR and RV as trial methods. Results were categorized into two groups, those with a ∆PSV > 10% and those with a ∆PSV ≤ 10%. ∆PSV mean and standard error, as well as measures of agreement were calculated. RESULTS Mean ∆PSV associated with PLR test was 9% in the 46° and 60° groups, and 18% in the 90° group, with standard errors of 6, 7, and 14%, respectively. Using 46° as our relative gold standard, Kappa was 0.23 at 60° and 0.11 at 90° with RV as the trial method, and 0.23 at 60° and 0.01 at 90° with a PLR as the trial method. CONCLUSIONS Variation in PSV is heavily dependent on insonation angle. There was only slight to fair agreement in ∆PSV among the various insonation angles. Further investigation of the optimal insonation angle to assess ∆PSV should be undertaken.
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Affiliation(s)
| | - George Lim
- Ronald Reagan-UCLA Medical Center, United States of America
| | - Alan T Chiem
- Olive View-UCLA Medical Center, United States of America.
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18
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Bechsgaard T, Hansen KL, Brandt A, Moshavegh R, Forman JL, Føgh P, Klitfod L, Bækgaard N, Lönn L, Jensen JA, Nielsen MB. Evaluation of Peak Reflux Velocities with Vector Flow Imaging and Spectral Doppler Ultrasound in Varicose Veins. Ultrasound Int Open 2018; 4:E91-E98. [PMID: 30276359 PMCID: PMC6162191 DOI: 10.1055/a-0643-4430] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/24/2018] [Accepted: 05/17/2018] [Indexed: 10/29/2022] Open
Abstract
Purpose Spectral Doppler ultrasound (SDUS) is used for quantifying reflux in lower extremity varicose veins. The technique is angle-dependent opposed to the new angle-independent Vector Flow Imaging (VFI) method. The aim of this study was to compare peak reflux velocities obtained with VFI and SDUS in patients with chronic venous disease, i. e., pathological retrograde blood flow caused by incompetent venous valves. Materials and Methods 64 patients with chronic venous disease were scanned with VFI and SDUS in the great or the small saphenous vein, and reflux velocities were compared to three assessment tools for chronic venous disease. A flow rig was used to assess the accuracy and precision of the two methods. Results The mean peak reflux velocities differed significantly (VFI: 47.4 cm/s vs. SDUS: 62.0 cm/s, p<0.001). No difference in absolute precision (p=0.18) nor relative precision (p=0.79) was found. No correlation to disease severity, according to assessment tools, was found for peak reflux velocities obtained with either method. In vitro, VFI was more accurate but equally precise when compared to SDUS. Conclusion Both VFI and SDUS detected the pathologic retrograde flow in varicose veins but measured different reflux velocities with equal precision. VFI may play a role in evaluating venous disease in the future.
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Affiliation(s)
| | | | - Andreas Brandt
- Copenhagen University Hospital Rigshospitalet, Department of Diagnostic Radiology, 2100 Copenhagen Oe, Denmark
| | - Ramin Moshavegh
- The Technical University of Denmark, Department of Electrical Engineering Center for Fast Ultrasound Imaging, 2800 Kgs. Lyngby, Denmark
| | - Julie Lyng Forman
- Copenhagen University, Department of Public Health Section of Biostatistics, 1014 Copenhagen K, Denmark
| | - Pia Føgh
- Copenhagen University Hospital Rigshospitalet, Department of Vascular Surgery Herlev & Gentofte Hospital, 2900 Hellerup, Denmark
| | - Lotte Klitfod
- Copenhagen University Hospital Rigshospitalet, Department of Vascular Surgery Herlev & Gentofte Hospital, 2900 Hellerup, Denmark
| | - Niels Bækgaard
- Copenhagen University Hospital Rigshospitalet, Department of Vascular Surgery Herlev & Gentofte Hospital, 2900 Hellerup, Denmark
| | - Lars Lönn
- Rigshospitalet, Copenhagen, DK, Radiology, Copenhagen, Denmark
| | - Jørgen Arendt Jensen
- Technical University of Denmark, Department of Electrical Engineering Center for Fast Ultrasound Imaging, 2800 Kgs. Lyngby, Denmark
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19
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Bechsgaard T, Hansen KL, Brandt AH, Moshavegh R, Forman JL, Føgh P, Klitfod L, Bækgaard N, Lönn L, Nielsen MB, Jensen JA. Respiratory variability of peak velocities in the common femoral vein estimated with vector flow imaging and Doppler ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:1941-1950. [PMID: 29960752 DOI: 10.1016/j.ultrasmedbio.2018.05.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 04/26/2018] [Accepted: 05/04/2018] [Indexed: 06/08/2023]
Abstract
Respiratory variability of peak velocities (RVPV) in the common femoral vein measured with ultrasound can reveal venous outflow obstruction. Pulse wave (PW) Doppler is the gold standard for venous velocity estimation of the lower extremities. PW Doppler measurements are angle dependent, whereas vector flow imaging (VFI) can yield angle-independent measures. The hypothesis of the present study was that VFI can provide RVPV estimations without the angle dependency of PW Doppler for an improved venous disease assessment. Sixty-seven patients with symptomatic chronic venous disease were included in the study. On average, VFI measured a lower RVPV than PW Doppler (VFI: 14.11 cm/s; PW: 17.32 cm/s, p = 0.002) with a non-significant improved precision compared with PW Doppler (VFI: 21.09%; PW: 26.49%, p = 0.08). In a flow phantom, VFI had improved accuracy (p < 0.01) and equal precision compared with PW Doppler. The study indicated that VFI can characterize the hemodynamic fluctuations in the common femoral vein.
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Affiliation(s)
- Thor Bechsgaard
- Department of Diagnostic Radiology, Rigshospitalet - Copenhagen University Hospital, Copenhagen Ø, Denmark.
| | - Kristoffer Lindskov Hansen
- Department of Diagnostic Radiology, Rigshospitalet - Copenhagen University Hospital, Copenhagen Ø, Denmark
| | - Andreas Hjelm Brandt
- Department of Diagnostic Radiology, Rigshospitalet - Copenhagen University Hospital, Copenhagen Ø, Denmark
| | - Ramin Moshavegh
- Center for Fast Ultrasound Imaging, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark
| | - Julie Lyng Forman
- Section of Biostatistics, Department of Public Health, Copenhagen University, Copenhagen K, Denmark
| | - Pia Føgh
- Department of Vascular Surgery, Rigshospitalet & Gentofte Hospital - Copenhagen University Hospital, Hellerup, Denmark
| | - Lotte Klitfod
- Department of Vascular Surgery, Rigshospitalet & Gentofte Hospital - Copenhagen University Hospital, Hellerup, Denmark
| | - Niels Bækgaard
- Department of Vascular Surgery, Rigshospitalet & Gentofte Hospital - Copenhagen University Hospital, Hellerup, Denmark
| | - Lars Lönn
- Department of Diagnostic Radiology, Rigshospitalet - Copenhagen University Hospital, Copenhagen Ø, Denmark
| | - Michael Bachmann Nielsen
- Department of Diagnostic Radiology, Rigshospitalet - Copenhagen University Hospital, Copenhagen Ø, Denmark
| | - Jørgen Arendt Jensen
- Center for Fast Ultrasound Imaging, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark
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20
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Brandt AH, Hansen KL, Ewertsen C, Holbek S, Olesen JB, Moshavegh R, Thomsen C, Jensen JA, Nielsen MB. A Comparison Study of Vector Velocity, Spectral Doppler and Magnetic Resonance of Blood Flow in the Common Carotid Artery. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:1751-1761. [PMID: 29804906 DOI: 10.1016/j.ultrasmedbio.2018.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 04/26/2018] [Accepted: 05/01/2018] [Indexed: 06/08/2023]
Abstract
Magnetic resonance phase contrast angiography (MRA) is the gold standard for blood flow evaluation. Spectral Doppler ultrasound (SDU) is the first clinical choice, although the method is angle dependent. Vector flow imaging (VFI) is an angle-independent ultrasound method. The aim of the study was to compare VFI- and SDU-estimated peak systolic velocities (PSV) of the common carotid artery (CCA) with PSV obtained by MRA. Furthermore, intra- and inter-observer agreement was determined. MRA estimates were significantly different from SDU estimates (left CCA: p < 0.001, right CCA: p < 0.001), but not from VFI estimates (left CCA: p = 0.28, right CCA: p = 0.18). VFI measured lower PSV in both CCAs compared with SDU (p < 0.001) with improved precision (VFI: left: 24%, right: 18%; SDU: left 38%, right: 23%). Intra- and inter-observer agreement was almost perfect for VFI and SDU (inter-observer correlation coefficient: VFI 0.88, SDU 0.91; intra-observer correlation coefficient: VFI 0.96, SDU 0.97). VFI is more accurate than SDU in evaluating PSV compared with MRA.
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Affiliation(s)
- Andreas Hjelm Brandt
- Department of Radiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
| | | | - Caroline Ewertsen
- Department of Radiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Simon Holbek
- Center for Fast Ultrasound Imaging, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark
| | - Jacob Bjerring Olesen
- Center for Fast Ultrasound Imaging, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark
| | - Ramin Moshavegh
- Center for Fast Ultrasound Imaging, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark
| | - Carsten Thomsen
- Department of Radiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark; Department of Radiology, Zealand University Hospital Roskilde, Roskilde, Denmark
| | - Jørgen Arendt Jensen
- Center for Fast Ultrasound Imaging, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark
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Brandt AH, Moshavegh R, Hansen KL, Bechsgaard T, Lönn L, Jensen JA, Nielsen MB. Vector Flow Imaging Compared with Pulse Wave Doppler for Estimation of Peak Velocity in the Portal Vein. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:593-601. [PMID: 29223701 DOI: 10.1016/j.ultrasmedbio.2017.10.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 10/25/2017] [Accepted: 10/30/2017] [Indexed: 06/07/2023]
Abstract
The study described here investigated whether angle-independent vector flow imaging (VFI) technique estimates peak velocities in the portal vein comparably to pulsed wave Doppler (PWD). Furthermore, intra- and inter-observer agreement was assessed in a substudy. VFI and PWD peak velocities were estimated with from intercostal and subcostal views for 32 healthy volunteers, and precision analyses were conducted. Blinded to estimates, three physicians rescanned 10 volunteers for intra- and inter-observer agreement analyses. The precision of VFI and PWD was 18% and 28% from an intercostal view and 23% and 77% from a subcostal view, respectively. Bias between VFI and PWD was 0.57 cm/s (p = 0.38) with an intercostal view and 9.89 cm/s (p <0.001) with a subcostal view. Intra- and inter-observer agreement was highest for VFI (inter-observer intra-class correlation coefficient: VFI 0.80, PWD 0.3; intra-observer intra-class correlation coefficient: VFI 0.90, PWD 0.69). Regardless of scan view, VFI was more precise than PWD.
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Affiliation(s)
- Andreas Hjelm Brandt
- Department of Radiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
| | - Ramin Moshavegh
- Center for Fast Ultrasound Imaging, Technical University of Denmark, Lyngby, Denmark
| | | | - Thor Bechsgaard
- Department of Radiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Lars Lönn
- Department of Radiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Jørgen Arendt Jensen
- Center for Fast Ultrasound Imaging, Technical University of Denmark, Lyngby, Denmark
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22
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Bechsgaard T, Hansen KL, Brandt AH, Holbek S, Forman JL, Strandberg C, Lönn L, Bækgaard N, Jensen JA, Nielsen MB. Vector and Doppler Ultrasound Velocities Evaluated in a Flow Phantom and the Femoropopliteal Vein. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:2477-2487. [PMID: 28750944 DOI: 10.1016/j.ultrasmedbio.2017.06.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 06/16/2017] [Accepted: 06/19/2017] [Indexed: 06/07/2023]
Abstract
Ultrasound is used for evaluating the veins of the lower extremities. Operator and angle dependency limit spectral Doppler ultrasound (SDUS). The aim of the study was to compare peak velocity measurements in a flow phantom and the femoropopliteal vein of 20 volunteers with the angle-independent vector velocity technique vector flow imaging (VFI) and SDUS. In the flow phantom, VFI underestimated velocity (p = 0.01), with a lower accuracy of 5.5% (p = 0.01) and with no difference in precision, that is, error factor, compared with SDUS (VFI: 1.02 vs. SDUS: 1.02, p = 0.58). In vivo, VFI estimated lower velocities (femoral: p = 0.001; popliteal: p = 0.001) with no difference in precision compared with SDUS (femoral: VFI 1.09 vs. SDUS 1.14, p = 0.37; popliteal: VFI 1.13 vs. SDUS 1.06, p = 0.09). In conclusion, the precise VFI technique can be used to characterize venous hemodynamics of the lower extremities despite its underestimation of velocities.
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Affiliation(s)
- Thor Bechsgaard
- Department of Radiology, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark.
| | | | - Andreas Hjelm Brandt
- Department of Radiology, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Simon Holbek
- Center for Fast Ultrasound Imaging, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark
| | - Julie Lyng Forman
- Section of Biostatistics, Department of Public Health, Copenhagen University, Copenhagen, Denmark
| | - Charlotte Strandberg
- Department of Radiology, University Hospital of Copenhagen, Herlev & Gentofte Hospital, Hellerup, Denmark
| | - Lars Lönn
- Department of Radiology, University Hospital of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Niels Bækgaard
- Department of Vascular Surgery, University Hospital of Copenhagen, Rigshospitalet & Gentofte Hospital, Hellerup, Denmark
| | - Jørgen Arendt Jensen
- Center for Fast Ultrasound Imaging, Department of Electrical Engineering, Technical University of Denmark, Lyngby, Denmark
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Paliulyte V, Drasutiene GS, Ramasauskaite D, Bartkeviciene D, Zakareviciene J, Kurmanavicius J. Physiological Uterine Involution in Primiparous and Multiparous Women: Ultrasound Study. Obstet Gynecol Int 2017; 2017:6739345. [PMID: 28555159 PMCID: PMC5438840 DOI: 10.1155/2017/6739345] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Accepted: 04/13/2017] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To examine the uterine involution period after uncomplicated delivery in primiparous and multiparous women. METHODS Longitudinal prospective study. Repeated parameters were measured and endometrial contents and diastolic notch were observed. Measurements of primiparous and multiparous women were carried out after labour on the 1st, 3rd, 10th, 30th, 42nd, and 60th postpartum days. The analysis was performed using SPSS version 21. RESULTS The median uterus parameters are bigger in multiparous group in physiological puerperium, but the decreasing trend is the same. The endometrial cavity on the 10th day was significantly wider in multiparous women and mainly echo-negative view of the uterine cavity was observed. The evaluation of the uterine angle deviation changes from an extremely retroverted position to a more anteverted position. RI of the uterine artery in both groups was low immediately after labour and significantly increased one month postpartum. Notching of the uterine artery undergoes changes, but diastolic notch does not appear in all postpartum women even after two months following labour. CONCLUSIONS The puerperium period after normal vaginal delivery depends on parity. The trend of involution in primiparous and multiparous women follows a similar pattern, yet, it lasts longer in the multiparous women. Ultrasound of uterine is certainly a useful tool after labour and may be important in facilitating an early detection of postpartum uterine complications.
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Affiliation(s)
- V. Paliulyte
- Clinic of Obstetrics and Gynaecology of Vilnius University, Centre of Obstetrics and Gynecology, Vilnius University Hospital Santariskiu Klinikos, Santariskiu 2, LT-08661 Vilnius, Lithuania
| | - G. S. Drasutiene
- Clinic of Obstetrics and Gynaecology of Vilnius University, Centre of Obstetrics and Gynecology, Vilnius University Hospital Santariskiu Klinikos, Santariskiu 2, LT-08661 Vilnius, Lithuania
| | - D. Ramasauskaite
- Clinic of Obstetrics and Gynaecology of Vilnius University, Centre of Obstetrics and Gynecology, Vilnius University Hospital Santariskiu Klinikos, Santariskiu 2, LT-08661 Vilnius, Lithuania
| | - D. Bartkeviciene
- Clinic of Obstetrics and Gynaecology of Vilnius University, Centre of Obstetrics and Gynecology, Vilnius University Hospital Santariskiu Klinikos, Santariskiu 2, LT-08661 Vilnius, Lithuania
| | - J. Zakareviciene
- Clinic of Obstetrics and Gynaecology of Vilnius University, Centre of Obstetrics and Gynecology, Vilnius University Hospital Santariskiu Klinikos, Santariskiu 2, LT-08661 Vilnius, Lithuania
| | - J. Kurmanavicius
- Department of Obstetrics, University Hospital Zurich, Zurich, Switzerland
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Hudson JM, Williams R, Milot L, Wei Q, Jago J, Burns PN. In Vivo Validation of Volume Flow Measurements of Pulsatile Flow Using a Clinical Ultrasound System and Matrix Array Transducer. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:579-585. [PMID: 27979667 DOI: 10.1016/j.ultrasmedbio.2016.10.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 10/18/2016] [Accepted: 10/26/2016] [Indexed: 06/06/2023]
Abstract
The goal of this study was to evaluate the accuracy of a non-invasive C-plane Doppler estimation of pulsatile blood flow in the lower abdominal vessels of a porcine model. Doppler ultrasound measurements from a matrix array transducer system were compared with invasive volume flow measurements made on the same vessels with a surgically implanted ultrasonic transit-time flow probe. For volume flow rates ranging from 60 to 750 mL/min, agreement was very good, with a Pearson correlation coefficient of 0.97 (p < 0.0001) and a mean bias of -4.2%. The combination of 2-D matrix array technology and fast processing gives this Doppler method clinical potential, as many of the user- and system-dependent parameters of previous methods, including explicit vessel angle and diameter measurements, are eliminated.
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Affiliation(s)
- John M Hudson
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Ross Williams
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Laurent Milot
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Qifeng Wei
- Philips Ultrasound, Bothell, Washington, USA
| | - James Jago
- Philips Ultrasound, Bothell, Washington, USA
| | - Peter N Burns
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.
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25
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Hansen KL, Møller-Sørensen H, Kjaergaard J, Jensen MB, Lund JT, Pedersen MM, Olesen JB, Jensen JA, Nielsen MB. Vector Flow Imaging Compared with Conventional Doppler Ultrasound and Thermodilution for Estimation of Blood Flow in the Ascending Aorta. ULTRASONIC IMAGING 2017; 39:3-18. [PMID: 26705136 DOI: 10.1177/0161734615620137] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Transverse oscillation (TO) is a real-time ultrasound vector flow method implemented on a commercial scanner. The TO setup was examined on a flowrig with constant and pulsatile flow. Subsequently, 25 patients undergoing cardiac bypass surgery were scanned intraoperatively with TO on the ascending aorta and compared to transesophageal echocardiography (TEE) and pulmonary artery catheter thermodilution (PACTD). On the flowrig, TO had a precision of 5.5%, 9.4% and 14.7%, a percentage error of 18.2%, 14.6% and 40.7%, and a mean bias of 0.4 cm/s, 36.8 ml/min and 32.4 ml/min for velocity and flow rate (constant and pulsatile) estimation. The correlation coefficients for all flowrig evaluations were 0.99 indicating systematic bias. After bias correction, the percentage error was reduced to 11.5%, 12.6% and 15.9% for velocity and flow rate (constant and pulsatile) estimation. In the in vivo setup, TO, TEE, and PACTD had a precision of 21.9%, 13.7%, and 12.0%. TO compared with TEE and PACTD had a mean bias of 12.6 cm/s and -0.08 l/min, and a percentage error of 23.4%, and 36.7%, respectively. The percentage error was reduced to 22.9% for the TEE comparison, but increased to 43.8% for the PACTD comparison, after correction for the systematic bias found in the flowrig. TO is a reliable and precise method for velocity and flow rate estimation on a flowrig. However, TO with the present setup, is not interchangeable with PACTD for cardiac volume flow estimation, but is a reliable and precise angle-independent ultrasound alternative for velocity estimation of cardiac flow.
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Affiliation(s)
| | - Hasse Møller-Sørensen
- 2 Department of Cardiothoracic Anesthesiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Jesper Kjaergaard
- 3 Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Maiken Brit Jensen
- 2 Department of Cardiothoracic Anesthesiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Jens Teglgaard Lund
- 4 Department of Cardiothoracic Surgery, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Mads Møller Pedersen
- 1 Department of Radiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Jacob Bjerring Olesen
- 5 Center for Fast Ultrasound Imaging, DTU Elektro, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Jørgen Arendt Jensen
- 5 Center for Fast Ultrasound Imaging, DTU Elektro, Technical University of Denmark, Kongens Lyngby, Denmark
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26
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Park MY, Jung SE, Choi JI, Byun JY. Optimization of beam-flow angles for Doppler ultrasound flow velocity measurements using slanted gel pads. SPRINGERPLUS 2016; 5:328. [PMID: 27064372 PMCID: PMC4791444 DOI: 10.1186/s40064-016-1977-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 03/06/2016] [Indexed: 11/21/2022]
Abstract
The aim of this study was to assess whether slanted gel pads can be used to optimize beam-flow angles and flow velocity measurements for Doppler ultrasound. The right carotid artery of a single healthy female volunteer was measured alternatively five times without and with an 18° angled slanted gel pad between the ultrasound transducer and skin by 13 radiologists. Beam-flow angles and peak systolic flow velocities (PSV) were measured along with assessment of spectral broadening. Beam-flow angles (P = 0.001) and PSV (P = 0.001) measurements showed a significant decrease when using slanted gel pads. The mean (±SD) beam-flow angles without and with the use of slanted gel pads were 66.7 (±4.2) and 56.1 (±5.8) degrees, respectively. The mean (±SD) PSVs without and with the use of slanted gel pads were 92.0 (±17.4) and 76.9 (±10.9) cm/s, respectively. There was a noticeable decrease in spectral broadening when using slanted gel pads. There was a significant linear correlation between beam-flow angle and peak systolic velocity. Coefficients of variation for peak systolic velocity without and with the use of gel pads were 18.9 and 14.2 %, respectively. These results demonstrate that slanted gel pads decrease beam-flow angles and overestimation of Doppler flow velocity measurements while potentially increasing the reliability of measurements.
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Affiliation(s)
- Michael Yong Park
- Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-Daero, Seocho-gu, Seoul, 06591 Korea
| | - Seung Eun Jung
- Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-Daero, Seocho-gu, Seoul, 06591 Korea
| | - Joon-Il Choi
- Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-Daero, Seocho-gu, Seoul, 06591 Korea
| | - Jae Young Byun
- Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-Daero, Seocho-gu, Seoul, 06591 Korea
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27
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Duplex Doppler Ultrasound of the Hepatic Artery: A Window to Diagnosis of Diffuse Liver Pathology. Ultrasound Q 2016; 32:58-66. [PMID: 26938035 DOI: 10.1097/ruq.0000000000000166] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The use of Doppler sonography for evaluation of the liver is well established, and evaluation of the portal and hepatic veins in native livers, as well as the hepatic artery in transplant livers, is a standard part of the examination. Less well known, however, is that assessment hepatic of artery blood flow velocities and waveforms can permit inferences to be made about liver and system pathophysiology even in native livers. This review will illustrate that hepatic parenchymal abnormalities, as well as primary vascular abnormalities both upstream and downstream of the proper hepatic artery, can be inferred from careful interrogation of its Doppler signature during routine abdominal sonography.
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28
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Iranpour P, Lall C, Houshyar R, Helmy M, Yang A, Choi JI, Ward G, Goodwin SC. Altered Doppler flow patterns in cirrhosis patients: an overview. Ultrasonography 2015; 35:3-12. [PMID: 26169079 PMCID: PMC4701371 DOI: 10.14366/usg.15020] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 05/27/2015] [Accepted: 05/27/2015] [Indexed: 12/12/2022] Open
Abstract
Doppler ultrasonography of the hepatic vasculature is an integral part of evaluating precirrhotic and cirrhotic patients. While the reversal of the portal venous flow is a well-recognized phenomenon, other flow patterns, although not as easily understood, may play an important role in assessing the disease status. This article discusses the different characteristic flow patterns observed from the portal vein, hepatic artery, and hepatic vein in patients with liver cirrhosis or related complications and procedures. Knowledge of these different flow patterns provides additional information that may reinforce the diagnosis of cirrhosis, help in staging, and offer prognostic information for determining the direction of therapy. Doppler ultrasonography is invaluable when liver transplantation is being considered and aids in the diagnosis of cirrhosis and portal hypertension.
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Affiliation(s)
- Pooya Iranpour
- Department of Radiology, University of California Irvine, Orange, CA, USA
| | - Chandana Lall
- Department of Radiology, University of California Irvine, Orange, CA, USA
| | - Roozbeh Houshyar
- Department of Radiology, University of California Irvine, Orange, CA, USA
| | - Mohammad Helmy
- Department of Radiology, University of California Irvine, Orange, CA, USA
| | - Albert Yang
- Department of Radiology, University of California Irvine, Orange, CA, USA
| | - Joon-Il Choi
- Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Garrett Ward
- Department of Radiology, University of California Irvine, Orange, CA, USA
| | - Scott C Goodwin
- Department of Radiology, University of California Irvine, Orange, CA, USA
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29
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Hansen KL, Møller-Sørensen H, Pedersen MM, Hansen PM, Kjaergaard J, Lund JT, Nilsson JC, Jensen JA, Nielsen MB. First report on intraoperative vector flow imaging of the heart among patients with healthy and diseased aortic valves. ULTRASONICS 2015; 56:243-250. [PMID: 25128079 DOI: 10.1016/j.ultras.2014.07.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 07/22/2014] [Accepted: 07/23/2014] [Indexed: 06/03/2023]
Abstract
The vector velocity method Transverse Oscillation (TO) implemented on a conventional ultrasound (US) scanner (ProFocus, BK Medical, Herlev, Denmark) can provide real-time, angle-independent estimates of the cardiac blood flow. During cardiac surgery, epicardial US examination using TO was performed on (A) 3 patients with healthy aortic valve and (B) 3 patients with aortic valve stenosis. In group B, the systolic flow of the ascending aorta had higher velocities, was more aliased and chaotic. The jet narrowed to 44% of the lumen compared to 75% in group A and with a vector concentration, a measure of flow complexity, of 0.41 compared to 0.87 in group A. The two groups had similar secondary flow of the ascending aorta with an average rotation frequency of 4.8 Hz. Simultaneous measurements were obtained with spectral Doppler (SD) and a thermodilution technique (TD). The mean difference in peak systolic velocity compared to SD in group A was 22% and 45% in B, while the mean difference in volume flow compared to TD in group A was 30% and 32% in B. TO can potentially reveal new information of cardiac blood flow, and may become a valuable diagnostic tool in the evaluation of patients with cardiovascular diseases.
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Affiliation(s)
| | - Hasse Møller-Sørensen
- Department of Cardiothoracic Anesthesiology, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - Mads Møller Pedersen
- Department of Radiology, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - Peter Møller Hansen
- Department of Radiology, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - Jesper Kjaergaard
- Department of Cardiology, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - Jens Teglgaard Lund
- Department of Cardiothoracic Surgery, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - Jens Christian Nilsson
- Department of Cardiothoracic Surgery, Rigshospitalet, Copenhagen University Hospital, Denmark
| | - Jørgen Arendt Jensen
- Center for Fast Ultrasound Imaging, DTU Elektro, Technical University of Denmark, Denmark
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30
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Intraoral Doppler sonography in edentulous patients. Oral Radiol 2014. [DOI: 10.1007/s11282-014-0168-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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