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Rice J, Bushman W, Roldán-Alzate A. Validation of Dynamic 3D MRI for Urodynamics Assessment Using an Anatomically Realistic In Vitro Model of the Bladder. J Biomech Eng 2024; 146:071007. [PMID: 38511303 PMCID: PMC11080948 DOI: 10.1115/1.4065110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 03/12/2024] [Accepted: 03/12/2024] [Indexed: 03/22/2024]
Abstract
Lowery urinary tract symptoms (LUTS) affect a large majority of the aging population. 3D Dynamic MRI shows promise as a noninvasive diagnostic tool that can assess bladder anatomy and function (urodynamics) while overcoming challenges associated with current urodynamic assessment methods. However, validation of this technique remains an unmet need. In this study, an anatomically realistic, bladder-mimicking in vitro flow model was created and used to systematically benchmark 3D dynamic MRI performance using a highly controllable syringe pump. Time-resolved volumes of the synthetic bladder model were obtained during simulated filling and voiding events and used to calculate volumetric flowrate. During MRI acquisitions, pressure during each event was recorded and used to create PV loops for work assessment. Error between control and MRI-derived volume for voiding and filling events exhibited 3.36% and 4.66% differences, respectively. A slight increase in average error was observed for MRI-derived flowrate when compared to the control flowrate (4.90% and 7.67% for voiding and filling, respectively). Overall, average error in segmented volumes increased with decreasing volume flowrate. Pressure drops were observed during voiding. Pressure increased during filling. Enhanced validation of novel 3D MRI urodynamics is achieved by using high-resolution PIV for visualizing and quantifying velocity inside the bladder model, which is not currently possible with 3D Dynamic MRI.
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Affiliation(s)
- James Rice
- Department of Mechanical Engineering, University of Wisconsin–Madison, Madison, WI 53705;Department of Radiology, University of Wisconsin–Madison, Madison, WI 53705
- University of Wisconsin–Madison
| | - Wade Bushman
- Department of Urology, University of Wisconsin–Madison, Madison, WI 53705
- University of Wisconsin–Madison
| | - Alejandro Roldán-Alzate
- Department of Radiology, University of Wisconsin–Madison, Madison, WI 53705;Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI 53705
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Xiong Z, Wang X, Yan Y, Liu Z, Luo X, Zheng T. A new computational fluid dynamics based noninvasive assessment of portacaval pressure gradient. J Biomech 2024; 167:112086. [PMID: 38615481 DOI: 10.1016/j.jbiomech.2024.112086] [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: 10/09/2023] [Revised: 03/27/2024] [Accepted: 04/04/2024] [Indexed: 04/16/2024]
Abstract
Accurate assessment of portacaval pressure gradient (PCG) in patients with portal hypertension (PH) is of great significance both for diagnosis and treatment. This study aims to develop a noninvasive method for assessing PCG in PH patients and evaluate its accuracy and effectiveness. This study recruited 37 PH patients treated with transjugular intrahepatic portosystemic shunt (TIPS). computed tomography angiography was used to create three dimension (3D) models of each patient before and after TIPS. Doppler ultrasound examinations were conducted to obtain the patient's portal vein flow (or splenic vein and superior mesenteric vein). Using computational fluid dynamics (CFD) simulation, the patient's pre-TIPS and post-TIPS PCG was determined by the 3D models and ultrasound measurements. The accuracy of these noninvasive results was then compared to clinical invasive measurements. The results showed a strong linear correlation between the PCG simulated by CFD and the clinical invasive measurements both before and after TIPS (R2 = 0.998, P < 0.001 and R2 = 0.959, P < 0.001). The evaluation accuracy of this noninvasive method reached 94 %, and the influence of ultrasound result errors on the numerical accuracy was found to be marginal if the error was less than 20 %. Furthermore, the information about the hemodynamic environment in the portal system was obtained by this numerical method. Spiral flow patterns were observed in the portal vein of some patients. In a conclusion, this study proposes a noninvasive numerical method for assessing PCG in PH patients before and after TIPS. This method can assist doctors in accurately diagnosing patients and selecting appropriate treatment plans. Additionally, it can be used to further investigate potential biomechanical causes of complications related to TIPS in the future.
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Affiliation(s)
- Zhuxiang Xiong
- Department of Mechanics, College of Architecture & Environment, Sichuan University, Chengdu 610065, China; Sichuan University Yibin Park / Yibin Institute of Industrial Technology, Yibin 644000, China
| | - Xiaoze Wang
- Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Yuling Yan
- Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Zhan Liu
- Department of Mechanics, College of Architecture & Environment, Sichuan University, Chengdu 610065, China; Sichuan University Yibin Park / Yibin Institute of Industrial Technology, Yibin 644000, China
| | - Xuefeng Luo
- Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Tinghui Zheng
- Department of Mechanics, College of Architecture & Environment, Sichuan University, Chengdu 610065, China; Sichuan University Yibin Park / Yibin Institute of Industrial Technology, Yibin 644000, China; West China Information Center, Sichuan University, Chengdu 610065, China.
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3
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Tithof J, Pruett TL, Rao JS. Lumped parameter liver simulation to predict acute haemodynamic alterations following partial resections. J R Soc Interface 2023; 20:20230444. [PMID: 37876272 PMCID: PMC10598422 DOI: 10.1098/rsif.2023.0444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/02/2023] [Indexed: 10/26/2023] Open
Abstract
Partial liver resections are routinely performed in living donor liver transplantation and to debulk tumours in liver malignancies, but surgical decisions on vessel reconstruction for adequate inflow and outflow are challenging. Pre-operative evaluation is often limited to radiological imaging, which fails to account for post-resection haemodynamic alterations. Substantial evidence suggests post-surgical increase in local volume flow rate enhances shear stress, signalling hepatic regeneration, but excessive shear stress has been postulated to result in small for size syndrome and liver failure. Predicting haemodynamic alterations throughout the liver is particularly challenging due to the dendritic architecture of the vasculature, spanning several orders of magnitude in diameter. Therefore, we developed a mathematical lumped parameter model with realistic heterogeneities capturing inflow/outflow of the human liver to simulate acute perfusion alterations following surgical resection. Our model is parametrized using clinical measurements, relies on a single free parameter and accurately captures established perfusion characteristics. We quantify acute changes in volume flow rate, flow speed and wall shear stress following variable, realistic liver resections and make comparisons with the intact liver. Our numerical model runs in minutes and can be adapted to patient-specific anatomy, providing a novel computational tool aimed at assisting pre- and intra-operative surgical decisions for liver resections.
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Affiliation(s)
- Jeffrey Tithof
- Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, MN 55455, USA
| | - Timothy L. Pruett
- Division of Solid Organ Transplantation, Department of Surgery, University of Minnesota, Minneapolis, MN, USA
| | - Joseph Sushil Rao
- Division of Solid Organ Transplantation, Department of Surgery, University of Minnesota, Minneapolis, MN, USA
- Schulze Diabetes Institute, Department of Surgery, University of Minnesota, 420 Delaware Street SE, Minneapolis, MN 55455, USA
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Huang A, Roberts GS, Roldán-Alzate A, Wieben O, Reeder SB, Oechtering TH. Reference values for 4D flow magnetic resonance imaging of the portal venous system. Abdom Radiol (NY) 2023; 48:2049-2059. [PMID: 37016247 PMCID: PMC10518803 DOI: 10.1007/s00261-023-03892-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 03/17/2023] [Accepted: 03/19/2023] [Indexed: 04/06/2023]
Abstract
PURPOSE The purpose of this work was to establish normal reference values for 4D flow MRI-derived flow, velocity, and vessel diameters, and to define characteristic flow patterns in the portal venous system of healthy adult subjects. METHODS For this retrospective study, we screened all available 4D flow MRI exams of the upper abdomen in healthy adults acquired at our institution between 2012 and 2022 at either 1.5 T or 3.0 T MRI after ≥ 5 h fasting. Flow, velocity, and effective diameter were quantified in the 8 planes in the portal venous system (splenic vein, superior mesenteric vein, main, right, and left portal veins). Vessel delineation was manually adjusted over time. Reference ranges for were defined as the mean ± 2 standard deviations. Three readers noted helical and vortical flow on time-resolved pathline visualizations. Conservation of mass flow analysis was performed for quality assurance. RESULTS We included 44 healthy subjects (26 female, 18-74 years) in the analysis. We report reference values for mean and peak flow, mean velocity, and vessel diameter in the healthy portal vein using 4D flow MRI. Normal flow patterns in the portal vein included faint helical (66%) or linear flow (34%). Conservation of mass analysis demonstrated a relative error of 1.1 ± 4.6% standard deviation (SD) at the splenomesenteric confluence and - 1.4 ± 4.1% SD at the portal bifurcation. CONCLUSION We have reported normal hemodynamic values that are necessary baseline data for emerging clinical applications of 4D flow MRI in the portal venous system. Results are consistent with previously published values from smaller cohorts.
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Affiliation(s)
- Andrew Huang
- Department of Radiology, University of Wisconsin, Madison, WI, USA
- Section of Vascular Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Grant S Roberts
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Alejandro Roldán-Alzate
- Department of Mechanical Engineering, University of Wisconsin, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
| | - Oliver Wieben
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Scott B Reeder
- Department of Radiology, University of Wisconsin, Madison, WI, USA
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
- Department of Medicine, University of Wisconsin, Madison, WI, USA
- Department of Emergency Medicine, University of Wisconsin, Madison, WI, USA
| | - Thekla H Oechtering
- Department of Radiology, University of Wisconsin, Madison, WI, USA.
- Department of Radiology and Nuclear Medicine, Universität zu Lübeck, Lübeck, Germany.
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Kawano Y, Tanabe M, Kameda F, Higashi M, Ihara K, Tanabe M, Inoue A, Kobayashi T, Ueda T, Ito K. Lobar hepatic steatosis: Association with portal flow hemodynamics evaluated by multiphasic dynamic contrast-enhanced CT. Eur J Radiol 2023; 160:110688. [PMID: 36630843 DOI: 10.1016/j.ejrad.2023.110688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/27/2022] [Accepted: 01/03/2023] [Indexed: 01/07/2023]
Abstract
PURPOSE This study aimed to evaluate the association of portal flow hemodynamics with lobar hepatic steatosis by means of dynamic contrast-enhanced (DCE) CT. METHODS The study population consisted of 235 patients, 77 with lobar hepatic steatosis (right, n = 67; left, n = 10), 158 with diffuse hepatic steatosis with (n = 76) and without (n = 82) a focal fatty spared area. CT attenuation values (Hounsfield units: HU) of the liver with and without hepatic steatosis were measured in unenhanced and arterial-phase CT. The contrast enhancement (CE) values were calculated as the difference in HU values between unenhanced and arterial-phase CT. RESULTS In 67 patients with lobar steatosis of the right lobe, the median CE values of the areas of right lobar steatosis were significantly lower than those of the non-fatty left lobe (13 [IQR 7-19] vs 23 [13-33] HU, P < 0.01), suggesting dominant SMV flow to the right lobe with lobar hepatic steatosis. Conversely, in 10 patients with lobar steatosis of the left lobe, the median CE values of the areas of left lobar steatosis were lower than those of the non-fatty right lobe (15.5 [11.75-21.5] vs 16 [14.5-22] HU); however, this difference was not statistically significant (P = 0.20). In 76 patients with a focal fatty spared area, there were significant differences in the median CE values between hepatic steatosis areas and focal fatty spared areas in the gallbladder fossa group (P = 0.01) and in the segment IV group (P < 0.01). CONCLUSION Lobar hepatic steatosis may be associated with regional changes of the portal flow hemodynamics (i.e., predominant perfusion from the SMV flow to the lobes with steatosis).
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Affiliation(s)
- Yosuke Kawano
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1, Minami-Kogushi, Ube, Yamaguchi 755-8505, JAPAN
| | - Masahiro Tanabe
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1, Minami-Kogushi, Ube, Yamaguchi 755-8505, JAPAN.
| | - Fumi Kameda
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1, Minami-Kogushi, Ube, Yamaguchi 755-8505, JAPAN
| | - Mayumi Higashi
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1, Minami-Kogushi, Ube, Yamaguchi 755-8505, JAPAN
| | - Kenichiro Ihara
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1, Minami-Kogushi, Ube, Yamaguchi 755-8505, JAPAN
| | - Masaya Tanabe
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1, Minami-Kogushi, Ube, Yamaguchi 755-8505, JAPAN
| | - Atsuo Inoue
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1, Minami-Kogushi, Ube, Yamaguchi 755-8505, JAPAN
| | - Taiga Kobayashi
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1, Minami-Kogushi, Ube, Yamaguchi 755-8505, JAPAN
| | - Takaaki Ueda
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1, Minami-Kogushi, Ube, Yamaguchi 755-8505, JAPAN
| | - Katsuyoshi Ito
- Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1, Minami-Kogushi, Ube, Yamaguchi 755-8505, JAPAN
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Yan Y, Xiong Z, Wang X, Yang L, Zheng T, Luo X. A novel potential mechanism for the development of portal vein thrombosis in cirrhosis based on portal hemodynamics. Insights Imaging 2022; 13:192. [PMID: 36512292 PMCID: PMC9748017 DOI: 10.1186/s13244-022-01330-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 11/06/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Marked changes in hemodynamics have been suggested to be a potential contributing factor to portal vein thrombosis (PVT) development. This study investigated the effect of portal hemodynamics based on the anatomical structure of the portal venous system on PVT development. METHODS The morphological features of portal venous system in patients with PVT and those without PVT subgroups were compared. In addition, idealized PV models were established to numerically evaluate the effect of the variation in the angulation of superior mesenteric vein (SMV) and splenic vein (SV) on the hemodynamics of portal venous system. RESULTS The angle α (angulation of SMV and SV) in patients with PVT was lower than that in patients without PVT (p < 0.0001), which was the only independent risk factor (odds ratio (OR), 0.90 (95% CI 0.84-0.95); p < 0.0001) for the presence of PVT. With the change in angle α, the flow pattern of blood flow changed greatly, especially the helical flow. When α = 80°, helical flow only appeared at the local PV near the intersection of SMV and SV. When α = 120°, most regions were occupied by the helical flow. In addition, the h2 gradually increased with increasing α, when α = 80°, h2 = 12.6 m/s2; when α = 120°, h2 = 29.3 m/s2. CONCLUSIONS The angulation of SV and SMV was closely associated with PVT development. Helical flow changed following the varying angulation of SV and SMV. Therefore, angulation of SV and SMV may help to identify high-risk cohorts for future PVT development earlier.
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Affiliation(s)
- Yuling Yan
- grid.412901.f0000 0004 1770 1022Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, 37 Guoxue Lane, Chengdu, 610041 Sichuan People’s Republic of China ,grid.13291.380000 0001 0807 1581Sichuan University-University of Oxford Huaxi Joint for Gastrointestinal Cancer Centre, Chengdu, Sichuan People’s Republic of China
| | - Zhuxiang Xiong
- grid.13291.380000 0001 0807 1581Department of Applied Mechanics, Sichuan University. No, 24 South Section of First Ring Road,, Chengdu, 610065 Sichuan Province People’s Republic of China ,grid.413041.30000 0004 1808 3369Yibin Institute of Industrial Technology/Sichuan University Yibin Park, Yibin, People’s Republic of China
| | - Xiaoze Wang
- grid.412901.f0000 0004 1770 1022Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, 37 Guoxue Lane, Chengdu, 610041 Sichuan People’s Republic of China ,grid.13291.380000 0001 0807 1581Sichuan University-University of Oxford Huaxi Joint for Gastrointestinal Cancer Centre, Chengdu, Sichuan People’s Republic of China
| | - Li Yang
- grid.412901.f0000 0004 1770 1022Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, 37 Guoxue Lane, Chengdu, 610041 Sichuan People’s Republic of China ,grid.13291.380000 0001 0807 1581Sichuan University-University of Oxford Huaxi Joint for Gastrointestinal Cancer Centre, Chengdu, Sichuan People’s Republic of China
| | - Tinghui Zheng
- grid.13291.380000 0001 0807 1581Department of Applied Mechanics, Sichuan University. No, 24 South Section of First Ring Road,, Chengdu, 610065 Sichuan Province People’s Republic of China ,grid.413041.30000 0004 1808 3369Yibin Institute of Industrial Technology/Sichuan University Yibin Park, Yibin, People’s Republic of China
| | - Xuefeng Luo
- grid.412901.f0000 0004 1770 1022Department of Gastroenterology and Hepatology, West China Hospital, Sichuan University, 37 Guoxue Lane, Chengdu, 610041 Sichuan People’s Republic of China ,grid.13291.380000 0001 0807 1581Sichuan University-University of Oxford Huaxi Joint for Gastrointestinal Cancer Centre, Chengdu, Sichuan People’s Republic of China
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Hyodo R, Takehara Y, Naganawa S. 4D Flow MRI in the portal venous system: imaging and analysis methods, and clinical applications. Radiol Med 2022; 127:1181-1198. [PMID: 36123520 PMCID: PMC9587937 DOI: 10.1007/s11547-022-01553-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 08/29/2022] [Indexed: 02/07/2023]
Abstract
Thus far, ultrasound, CT, and 2D cine phase-contrast MRI has been adopted to evaluate blood flow and vascular morphology in the portal venous system; however, all these techniques have some shortcomings, such as limited field of view and difficulty in accurately evaluating blood flow. A new imaging technique, namely 3D cine phase-contrast (4D Flow) MRI, can acquire blood flow data of the entire abdomen at once and in a time-resolved manner, allowing visual, quantitative, and comprehensive assessment of blood flow in the portal venous system. In addition, a retrospective blood flow analysis, i.e., "retrospective flowmetry," is possible. Although the development of 4D Flow MRI for the portal system has been delayed compared to that for the arterial system owing to the lower flow velocity of the portal venous system and the presence of respiratory artifacts, several useful reports have recently been published as the technology has advanced. In the first part of this narrative review article, technical considerations of image acquisition and analysis methods of 4D Flow MRI for the portal venous system and the validations of their results are described. In the second part, the current clinical application of 4D Flow MRI for the portal venous system is reviewed.
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Affiliation(s)
- Ryota Hyodo
- Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
| | - Yasuo Takehara
- Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
- Department of Fundamental Development for Advanced Low Invasive Diagnostic Imaging, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shinji Naganawa
- Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
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Oechtering TH, Roberts GS, Panagiotopoulos N, Wieben O, Reeder SB, Roldán-Alzate A. Clinical Applications of 4D Flow MRI in the Portal Venous System. Magn Reson Med Sci 2022; 21:340-353. [PMID: 35082218 PMCID: PMC9680553 DOI: 10.2463/mrms.rev.2021-0105] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 10/13/2021] [Indexed: 09/27/2023] Open
Abstract
Evaluation of the hemodynamics in the portal venous system plays an essential role in many hepatic pathologies. Changes in portal flow and vessel morphology are often indicative of disease.Routinely used imaging modalities, such as CT, ultrasound, invasive angiography, and MRI, often focus on either hemodynamics or anatomical imaging. In contrast, 4D flow MRI facilitiates a more comprehensive understanding of pathophysiological mechanisms by simultaneously and noninvasively acquiring time-resolved flow and anatomical information in a 3D imaging volume.Though promising, 4D flow MRI in the portal venous system is especially challenging due to small vessel calibers, slow flow velocities, and breathing motion. In this review article, we will discuss how to account for these challenges when planning and conducting 4D flow MRI acquisitions in the upper abdomen. We will address patient preparation, sequence acquisition, postprocessing, quality control, and analysis of 4D flow data.In the second part of this article, we will review potential clinical applications of 4D flow MRI in the portal venous system. The most promising area for clinical utilization is the diagnosis and grading of liver cirrhosis and its complications. Relevant parameters acquired by 4D flow MRI include the detection of reduced or reversed flow in the portal venous system, characterization of portosystemic collaterals, and impaired response to a meal challenge. In patients with cirrhosis, 4D flow MRI has the potential to address the major unmet need of noninvasive detection of gastroesophageal varices at high risk for bleeding. This could replace many unnecessary, purely diagnostic, and invasive esophagogastroduodenoscopy procedures, thereby improving patient compliance with follow-up. Moreover, 4D flow MRI offers unique insights and added value for surgical planning and follow-up of multiple hepatic interventions, including transjugular intrahepatic portosystemic shunts, liver transplantation, and hepatic disease in children. Lastly, we will discuss the path to clinical implementation and remaining challenges.
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Affiliation(s)
- Thekla H. Oechtering
- Department of Radiology, University of Wisconsin, Madison, WI, USA
- Department of Radiology, Universität zu Lübeck, Luebeck, Germany
| | - Grant S. Roberts
- Department of Medical Physics, University of Wisconsin, Madison, WI, USA
| | - Nikolaos Panagiotopoulos
- Department of Radiology, University of Wisconsin, Madison, WI, USA
- Department of Radiology, Universität zu Lübeck, Luebeck, Germany
| | - Oliver Wieben
- Department of Radiology, University of Wisconsin, Madison, WI, USA
- Department of Medical Physics, University of Wisconsin, Madison, WI, USA
| | - Scott B. Reeder
- Department of Radiology, University of Wisconsin, Madison, WI, USA
- Department of Medical Physics, University of Wisconsin, Madison, WI, USA
- Department of Mechanical Engineering, University of Wisconsin, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
- Department of Emergency, University of Wisconsin Medicine, Madison, WI, USA
| | - Alejandro Roldán-Alzate
- Department of Radiology, University of Wisconsin, Madison, WI, USA
- Department of Mechanical Engineering, University of Wisconsin, Madison, WI, USA
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
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9
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Seyedpour SM, Nabati M, Lambers L, Nafisi S, Tautenhahn HM, Sack I, Reichenbach JR, Ricken T. Application of Magnetic Resonance Imaging in Liver Biomechanics: A Systematic Review. Front Physiol 2021; 12:733393. [PMID: 34630152 PMCID: PMC8493836 DOI: 10.3389/fphys.2021.733393] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/25/2021] [Indexed: 12/15/2022] Open
Abstract
MRI-based biomechanical studies can provide a deep understanding of the mechanisms governing liver function, its mechanical performance but also liver diseases. In addition, comprehensive modeling of the liver can help improve liver disease treatment. Furthermore, such studies demonstrate the beginning of an engineering-level approach to how the liver disease affects material properties and liver function. Aimed at researchers in the field of MRI-based liver simulation, research articles pertinent to MRI-based liver modeling were identified, reviewed, and summarized systematically. Various MRI applications for liver biomechanics are highlighted, and the limitations of different viscoelastic models used in magnetic resonance elastography are addressed. The clinical application of the simulations and the diseases studied are also discussed. Based on the developed questionnaire, the papers' quality was assessed, and of the 46 reviewed papers, 32 papers were determined to be of high-quality. Due to the lack of the suitable material models for different liver diseases studied by magnetic resonance elastography, researchers may consider the effect of liver diseases on constitutive models. In the future, research groups may incorporate various aspects of machine learning (ML) into constitutive models and MRI data extraction to further refine the study methodology. Moreover, researchers should strive for further reproducibility and rigorous model validation and verification.
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Affiliation(s)
- Seyed M. Seyedpour
- Institute of Mechanics, Structural Analysis and Dynamics, Faculty of Aerospace Engineering and Geodesy, University of Stuttgart, Stuttgart, Germany
- Biomechanics Lab, Institute of Mechanics, Structural Analysis and Dynamics, Faculty of Aerospace Engineering and Geodesy, University of Stuttgart, Stuttgart, Germany
| | - Mehdi Nabati
- Department of Mechanical Engineering, Faculty of Engineering, Boğaziçi University, Istanbul, Turkey
| | - Lena Lambers
- Institute of Mechanics, Structural Analysis and Dynamics, Faculty of Aerospace Engineering and Geodesy, University of Stuttgart, Stuttgart, Germany
- Biomechanics Lab, Institute of Mechanics, Structural Analysis and Dynamics, Faculty of Aerospace Engineering and Geodesy, University of Stuttgart, Stuttgart, Germany
| | - Sara Nafisi
- Faculty of Pharmacy, Istinye University, Istanbul, Turkey
| | - Hans-Michael Tautenhahn
- Department of General, Visceral and Vascular Surgery, Jena University Hospital, Jena, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Campus Charité Mitte, Berlin, Germany
| | - Jürgen R. Reichenbach
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital-Friedrich Schiller University Jena, Jena, Germany
- Center of Medical Optics and Photonics, Friedrich Schiller University, Jena, Germany
- Michael Stifel Center for Data-driven and Simulation Science Jena, Friedrich Schiller University, Jena, Germany
| | - Tim Ricken
- Institute of Mechanics, Structural Analysis and Dynamics, Faculty of Aerospace Engineering and Geodesy, University of Stuttgart, Stuttgart, Germany
- Biomechanics Lab, Institute of Mechanics, Structural Analysis and Dynamics, Faculty of Aerospace Engineering and Geodesy, University of Stuttgart, Stuttgart, Germany
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10
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Rutkowski DR, Roldán-Alzate A, Johnson KM. Enhancement of cerebrovascular 4D flow MRI velocity fields using machine learning and computational fluid dynamics simulation data. Sci Rep 2021; 11:10240. [PMID: 33986368 PMCID: PMC8119419 DOI: 10.1038/s41598-021-89636-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 04/29/2021] [Indexed: 12/12/2022] Open
Abstract
Blood flow metrics obtained with four-dimensional (4D) flow phase contrast (PC) magnetic resonance imaging (MRI) can be of great value in clinical and experimental cerebrovascular analysis. However, limitations in both quantitative and qualitative analyses can result from errors inherent to PC MRI. One method that excels in creating low-error, physics-based, velocity fields is computational fluid dynamics (CFD). Augmentation of cerebral 4D flow MRI data with CFD-informed neural networks may provide a method to produce highly accurate physiological flow fields. In this preliminary study, the potential utility of such a method was demonstrated by using high resolution patient-specific CFD data to train a convolutional neural network, and then using the trained network to enhance MRI-derived velocity fields in cerebral blood vessel data sets. Through testing on simulated images, phantom data, and cerebrovascular 4D flow data from 20 patients, the trained network successfully de-noised flow images, decreased velocity error, and enhanced near-vessel-wall velocity quantification and visualization. Such image enhancement can improve experimental and clinical qualitative and quantitative cerebrovascular PC MRI analysis.
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Affiliation(s)
- David R Rutkowski
- Mechanical Engineering, University of Wisconsin, Madison, WI, USA
- Radiology, University of Wisconsin, 1111 Highland Ave, Madison, WI, USA
| | - Alejandro Roldán-Alzate
- Mechanical Engineering, University of Wisconsin, Madison, WI, USA
- Radiology, University of Wisconsin, 1111 Highland Ave, Madison, WI, USA
| | - Kevin M Johnson
- Radiology, University of Wisconsin, 1111 Highland Ave, Madison, WI, USA.
- Medical Physics, University of Wisconsin, 1111 Highland Ave, Madison, WI, USA.
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Brunsing RL, Brown D, Almahoud H, Kono Y, Loomba R, Vodkin I, Sirlin CB, Alley MT, Vasanawala SS, Hsiao A. Quantification of the Hemodynamic Changes of Cirrhosis with Free-Breathing Self-Navigated MRI. J Magn Reson Imaging 2021; 53:1410-1421. [PMID: 33594733 PMCID: PMC9161739 DOI: 10.1002/jmri.27488] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Non-invasive assessment of the hemodynamic changes of cirrhosis might help guide management of patients with liver disease but are currently limited. PURPOSE To determine whether free-breathing 4D flow MRI can be used to quantify the hemodynamic effects of cirrhosis and introduce hydraulic circuit indexes of severity. STUDY TYPE Retrospective. POPULATION Forty-seven patients including 26 with cirrhosis. FIELD STRENGTH/SEQUENCE 3 T/free-breathing 4D flow MRI with soft gating and golden-angle view ordering. ASSESSMENT Measurements of the supra-celiac abdominal aorta, supra-renal abdominal aorta (SRA), celiac trunk (CeT), superior mesenteric artery (SMA), splenic artery (SpA), common hepatic artery (CHA), portal vein (PV), and supra-renal inferior vena cava (IVC) were made by two radiologists. Measures of hepatic vascular resistance (hepatic arterial relative resistance [HARR]; portal resistive index [PRI]) were proposed and calculated. STATISTICAL ANALYSIS Bland-Altman, Pearson's correlation, Tukey's multiple comparison, and Cohen's kappa. P < 0.05 was considered significant. RESULTS Forty-four of 47 studies yielded adequate image quality for flow quantification (94%). Arterial structures showed high inter-reader concordance (range; ρ = 0.948-0.987) and the IVC (ρ = 0.972), with moderate concordance in the PV (ρ = 0.866). Conservation of mass analysis showed concordance between large vessels (SRA vs. IVC; ρ = 0.806), small vessels (celiac vs. CHA + SpA; ρ = 0.939), and across capillary beds (CeT + SMA vs. PV; ρ = 0.862). Splanchnic flow was increased in patients with portosystemic shunting (PSS) relative to control patients and patients with cirrhosis without PSS (P < 0.05, difference range 0.11-0.68 liter/m). HARR was elevated and PRI was decreased in patients with PSS (3.55 and 1.49, respectively) compared to both the control (2.11/3.18) and non-PSS (2.11/2.35) cohorts. DATA CONCLUSION 4D flow MRI with self-navigation was technically feasible, showing promise in quantifying the hemodynamic effects of cirrhosis. Proposed quantitative metrics of hepatic vascular resistance correlated with PSS. LEVEL OF EVIDENCE 3 TECHNICAL EFFICACY STAGE: 2.
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Affiliation(s)
- Ryan L Brunsing
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Dustin Brown
- Department of Radiology, University of California San Diego, La Jolla, California, USA
| | - Hashem Almahoud
- Department of Radiology, University of California San Diego, La Jolla, California, USA
| | - Yuko Kono
- Department of Radiology, Stanford University, Palo Alto, California, USA
- Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Rohit Loomba
- Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, California, USA
- Division of Epidemiology, Department of Family Medicine and Preventive Medicine, University of California San Diego, La Jolla, California, USA
- NAFLD Research Center, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Irene Vodkin
- Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Claude B Sirlin
- Department of Radiology, University of California San Diego, La Jolla, California, USA
| | - Marcus T Alley
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | | | - Albert Hsiao
- Department of Radiology, University of California San Diego, La Jolla, California, USA
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12
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Haarbye SO, Nielsen MB, Hansen AE, Lauridsen CA. Four-Dimensional Flow MRI of Abdominal Veins: A Systematic Review. Diagnostics (Basel) 2021; 11:767. [PMID: 33923366 PMCID: PMC8146887 DOI: 10.3390/diagnostics11050767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/21/2021] [Accepted: 04/21/2021] [Indexed: 11/25/2022] Open
Abstract
The aim of this systematic review is to provide an overview of the use of Four-Dimensional Magnetic Resonance Imaging of vector blood flow (4D Flow MRI) in the abdominal veins. This study was composed according to the PRISMA guidelines 2009. The literature search was conducted in MEDLINE, Cochrane Library, EMBASE, and Web of Science. Quality assessment of the included studies was performed using the QUADAS-2 tool. The initial search yielded 781 studies and 21 studies were included. All studies successfully applied 4D Flow MRI in abdominal veins. Four-Dimensional Flow MRI was capable of discerning between healthy subjects and patients with cirrhosis and/or portal hypertension. The visual quality and inter-observer agreement of 4D Flow MRI were rated as excellent and good to excellent, respectively, and the studies utilized several different MRI data sampling strategies. By applying spiral sampling with compressed sensing to 4D Flow MRI, the blood flow of several abdominal veins could be imaged simultaneously in 18-25 s, without a significant loss of visual quality. Four-Dimensional Flow MRI might be a useful alternative to Doppler sonography for the diagnosis of cirrhosis and portal hypertension. Further clinical studies need to establish consensus regarding MRI sampling strategies in patients and healthy subjects.
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Affiliation(s)
- Simon O. Haarbye
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark; (M.B.N.); (A.E.H.); (C.A.L.)
- Department of Technology, Faculty of Health and Technology, Metropolitan University College, DK-2100 Copenhagen, Denmark
| | - Michael B. Nielsen
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark; (M.B.N.); (A.E.H.); (C.A.L.)
- Department of Clinical Medicine, University of Copenhagen, DK-1165 Copenhagen, Denmark
| | - Adam E. Hansen
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark; (M.B.N.); (A.E.H.); (C.A.L.)
- Department of Clinical Medicine, University of Copenhagen, DK-1165 Copenhagen, Denmark
| | - Carsten A. Lauridsen
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark; (M.B.N.); (A.E.H.); (C.A.L.)
- Department of Technology, Faculty of Health and Technology, Metropolitan University College, DK-2100 Copenhagen, Denmark
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Rutkowski D, Medero R, Ruesink T, Roldan-Alzate A. Modeling Physiological Flow Variation in Fontan Models with 4d Flow Mri, Particle Image Velocimetry, and Arterial Spin Labeling. J Biomech Eng 2019; 141:1065454. [PMID: 31596919 DOI: 10.1115/1.4045110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Indexed: 11/08/2022]
Abstract
The Fontan procedure is a successful palliation for single ventricle defect. Yet, a number of complications still occur in Fontan patients due to abnormal blood flow dynamics, necessitating improved flow analysis and treatment methods. Phase-contrast magnetic resonance imaging (MRI) has emerged as a suitable method for such flow analysis. However, limitations on altering physiological blood flow conditions in the patient while in the MRI bore inhibit experimental investigation of a variety of factors that contribute to impaired cardiovascular health in these patients. Furthermore, resolution and flow regime limitations in phase contrast MRI pose a challenge for accurate and consistent flow characterization. In this study, patient-specific physical models were created based on nine Fontan geometries and MRI experiments mimicking low and high flow conditions, as well as steady and pulsatile flow, were conducted. Additionally, an optically transparent Fontan model was created for flow analyses using a particle image velocimetry (PIV) system, arterial spin labeling (ASL), and four-dimensional (4D) flow MRI. Differences, though non-statistically significant, were observed between flow conditions and between patient-specific models. Large between-model variation supported the need for further improvement for patient-specific modeling on each unique Fontan anatomical configuration. Furthermore, high resolution PIV and flow tracking ASL data provided flow information that was not obtainable with 4D flow MRI alone.
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Affiliation(s)
- David Rutkowski
- Mechanical Engineering, University of Wisconsin - Madison, Madison, WI, United States; Radiology, University of Wisconsin - Madison, Madison, WI, United States
| | - Rafael Medero
- Mechanical Engineering, University of Wisconsin - Madison, Madison, WI, United States; Radiology, University of Wisconsin - Madison, Madison, WI, United States
| | - Timothy Ruesink
- Mechanical Engineering, University of Wisconsin - Madison, Madison, WI, United States; Radiology, University of Wisconsin - Madison, Madison, WI, United States
| | - Alejandro Roldan-Alzate
- Mechanical Engineering, University of Wisconsin - Madison, Madison, WI, United States; Radiology, University of Wisconsin - Madison, Madison, WI, United States; Biomedical Engineering, University of Wisconsin - Madison, Madison, WI, United States
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Falk KL, Medero R, Roldán-Alzate A. Fabrication of Low-Cost Patient-Specific Vascular Models for Particle Image Velocimetry. Cardiovasc Eng Technol 2019; 10:500-507. [PMID: 31098919 PMCID: PMC7877060 DOI: 10.1007/s13239-019-00417-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 05/06/2019] [Indexed: 11/24/2022]
Abstract
PURPOSE Particle image velocimetry (PIV), an in vitro experimentation technique that optically measures velocity components to analyze fluid velocity fields, has become increasingly popular to study flow dynamics in various vascular territories. However, it can be difficult and expensive to create patient-specific clear models for PIV due to the importance of refractive index matching of the model and the fluid. We aim to implement and test the use of poly-vinyl alcohol (PVA) in a lost-core casting technique to create low-cost, patient-specific models for PIV. METHODS Anonymized patient vascular anatomies were segmented and processed in Mimics/3Matic to create patient-specific cores from 3D digital subtraction angiographies. The cores were 3D-printed with PVA and post-processed with a 80:20 water:glue mixture to smooth the surface. Two silicones, Sylgard 184 and Solaris, were used to encapsulate the model and the PVA core was dissolved using warm water. Computed tomography scans were used to evaluate geometric accuracy using circumferences and surface differences in the model. RESULTS Mean geometric differences in circumference along the inlet centerline and the mean surface difference in the aneurysm between the final Silicone Model and the desired STL Print geometry were statistically insignificant (0.6 mm, 95% CI [- 1.4, 2.8] and 0.3 mm 95% CI [- 0.1, 0.7], respectively). Particle illumination within each model was successful. The cost of one 10 cm × 10 cm × 5 cm model was $69. CONCLUSION This technique was successful to implement and test the use of PVA in a lost-core casting technique to create low-cost, patient-specific in vitro models for PIV experimentation.
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Affiliation(s)
- Katrina L Falk
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Department of Radiology, WIMR, University of Wisconsin-Madison, 2476, 1111 Highland Ave, Madison, WI, 53705, USA
| | - Rafael Medero
- Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Department of Radiology, WIMR, University of Wisconsin-Madison, 2476, 1111 Highland Ave, Madison, WI, 53705, USA
| | - Alejandro Roldán-Alzate
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.
- Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, USA.
- Department of Radiology, WIMR, University of Wisconsin-Madison, 2476, 1111 Highland Ave, Madison, WI, 53705, USA.
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