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  • 1.
    Carlhäll, Carljohan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Kindberg, Katarina
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Daughters, GT
    Miller, DC
    Ingels, NB
    Regional contribution of mitral annular dynamics to LV filling2006In: Experimental Biology,2006, 2006, p. A1194-A1194Conference paper (Other academic)
  • 2.
    Carlhäll, Carljohan
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Kindberg, Katarina
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Wigström, Lars
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Daughters, G. T.
    Linköping University, Faculty of Health Sciences.
    Millers, D. C.
    Linköping University, Faculty of Health Sciences.
    Karlsson, Matts
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Ingels Jr, N. B.
    Linköping University, Faculty of Health Sciences.
    Contribution of mitral annular dynamics to LV diastolic filling with alteration in preload and inotropic state2007In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 293, no 3, p. G1473-H1479Article in journal (Refereed)
    Abstract [en]

    Mitral annular (MA) excursion during diastole encompasses a volume that is part of total left ventricular (LV) filling volume (LVFV). Altered excursion or area variation of the MA due to changes in preload or inotropic state could affect LV filling. We hypothesized that changes in LV preload and inotropic state would not alter the contribution of MA dynamics to LVFV. Six sheep underwent marker implantation in the LV wall and around the MA. After 7–10 days, biplane fluoroscopy was used to obtain three-dimensional marker dynamics from sedated, closed-chest animals during control conditions, inotropic augmentation with calcium (Ca), preload reduction with nitroprusside (N), and vena caval occlusion (VCO). The contribution of MA dynamics to total LVFV was assessed using volume estimates based on multiple tetrahedra defined by the three-dimensional marker positions. Neither the absolute nor the relative contribution of MA dynamics to LVFV changed with Ca or N, although MA area decreased (Ca, P < 0.01; and N, P < 0.05) and excursion increased (Ca, P < 0.01). During VCO, the absolute contribution of MA dynamics to LVFV decreased (P < 0.001), based on a reduction in both area (P < 0.001) and excursion (P < 0.01), but the relative contribution to LVFV increased from 18 ± 4 to 45 ± 13% (P < 0.001). Thus MA dynamics contribute substantially to LV diastolic filling. Although MA excursion and mean area change with moderate preload reduction and inotropic augmentation, the contribution of MA dynamics to total LVFV is constant with sizeable magnitude. With marked preload reduction (VCO), the contribution of MA dynamics to LVFV becomes even more important.

  • 3.
    Kindberg, Katarina
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Applied statistics: Analysing myocardial strain tensors at two times and at three wall depths2006Report (Other academic)
  • 4.
    Kindberg, Katarina
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Connection between strain in cardiac coordinates and strain in fiber coordinates2005Report (Other academic)
  • 5.
    Kindberg, Katarina
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Detailed description of an implementation of finite element strain computation2005Report (Other academic)
  • 6.
    Kindberg, Katarina
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Invasive and Non-Invasive Quantification of Cardiac Kinematics2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The ability to measure and quantify myocardial motion and deformation provides a useful tool to assist in the diagnosis, prognosis and management of heart disease. Myocardial motion can be measured by means of several different types of data acquisition. The earliest myocardial motion tracking technique was invasive, based on implanting radiopaque markers into the myocardium around the left ventricle, and recording the marker positions during the cardiac cycle by biplane cineradiography. Until recently, this was the only method with high enough spatial resolution of three-dimensional (3D) myocardial displacements to resolve transmural behaviors. However, the recent development of magnetic resonance imaging techniques, such as displacement encoding with stimulated echoes (DENSE), make detailed non-invasive 3D transmural kinematic analyses of human myocardium possible in the clinic and for research purposes.

    Diastolic left ventricular filling is a highly dynamic process with early and late transmitral inflows and it is determined by a complex sequence of many interrelated events and parameters. Extensive research has been performed to describe myocardial kinematics during the systolic phase of the cardiac cycle, but not by far the same amount of research has been accomplished during diastole. Measures of global and regional left ventricular kinematics during diastole are important when attempting to understand left ventricular filling characteristics in health and disease.

    This thesis presents methods for invasive and non-invasive quantification of cardiac kinematics, with focus on diastole. The project started by quantification of changes in global left ventricular kinematics during diastolic filling. The helical myocardial fiber architecture of the left ventricle produces both long- and short-axis motion as well as torsional deformation. The longitudinal excursion of the mitral annular plane is an important component of left ventricular filling and ejection. This was studied by analyzing the contribution of mitral annular dynamics to left ventricular filling volume in the ovine heart.

    In order to quantify strains for a specific body undergoing deformation, displacements for a set of internal points at a deformed configuration relative to a reference configuration are needed. A new method for strain quantification from measured myocardial displacements is presented in this thesis. The method is accurate and robust and delivers analytical expressions of the strain components. The developed strain quantification method is simple in nature which aids to bridge a possible gap in understanding between different disciplines and is well suited for sparse arrays of displacement data.

    Analyses of myocardial kinematics at the level of myocardial fibers require knowledge of cardiac tissue architecture. Temporal changes in myofiber directions during the cardiac cycle have been analyzed in the ovine heart by combining histological measurements of transmural myocardial architecture and local transmural strains.

    Rapid early diastolic filling is an essential component of the left ventricular function. Such filling requires a highly compliant chamber immediately after systole, allowing inflow at low driving pressures. Failure of this process can lead to exercise intolerance and ultimately to heart failure. A thorough analysis of the relation between global left ventricular kinematics and local myocardial strain at the level of myocardial fibers during early diastole in the ovine heart was performed by applying the method for strain quantification and the technique for computing temporal changes in myocardial architecture on measures of myocardial displacements and tissue architecture in the ovine heart.

    As data acquisition technologies develop, quantification methods for cardiac kinematics need to be adapted and validated on the new types of data. Recent improvements of DENSE magnetic resonance imaging enable non-invasive transmural strain analyses in the human heart. The strain quantification method was first tailored to displacement data from a surgically implanted bead array but has been extended to applications on non-invasive DENSE data measured in two and three dimensions. Validation against an analytical standard reveals accurate results and in vivo strains agree with values for normal human hearts from other studies.

    The method has in this thesis been used with displacement data from invasive marker technology and non-invasive DENSE magnetic resonance imaging, but can equally well be applied on any type of displacement data provided that the spatial resolution is high enough to resolve local strain variations.

    List of papers
    1. Contribution of mitral annular dynamics to LV diastolic filling with alteration in preload and inotropic state
    Open this publication in new window or tab >>Contribution of mitral annular dynamics to LV diastolic filling with alteration in preload and inotropic state
    Show others...
    2007 (English)In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 293, no 3, p. G1473-H1479Article in journal (Refereed) Published
    Abstract [en]

    Mitral annular (MA) excursion during diastole encompasses a volume that is part of total left ventricular (LV) filling volume (LVFV). Altered excursion or area variation of the MA due to changes in preload or inotropic state could affect LV filling. We hypothesized that changes in LV preload and inotropic state would not alter the contribution of MA dynamics to LVFV. Six sheep underwent marker implantation in the LV wall and around the MA. After 7–10 days, biplane fluoroscopy was used to obtain three-dimensional marker dynamics from sedated, closed-chest animals during control conditions, inotropic augmentation with calcium (Ca), preload reduction with nitroprusside (N), and vena caval occlusion (VCO). The contribution of MA dynamics to total LVFV was assessed using volume estimates based on multiple tetrahedra defined by the three-dimensional marker positions. Neither the absolute nor the relative contribution of MA dynamics to LVFV changed with Ca or N, although MA area decreased (Ca, P < 0.01; and N, P < 0.05) and excursion increased (Ca, P < 0.01). During VCO, the absolute contribution of MA dynamics to LVFV decreased (P < 0.001), based on a reduction in both area (P < 0.001) and excursion (P < 0.01), but the relative contribution to LVFV increased from 18 ± 4 to 45 ± 13% (P < 0.001). Thus MA dynamics contribute substantially to LV diastolic filling. Although MA excursion and mean area change with moderate preload reduction and inotropic augmentation, the contribution of MA dynamics to total LVFV is constant with sizeable magnitude. With marked preload reduction (VCO), the contribution of MA dynamics to LVFV becomes even more important.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-41883 (URN)10.1152/ajpheart.00208.2007 (DOI)59289 (Local ID)59289 (Archive number)59289 (OAI)
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
    2. Nonhomogeneous strain from sparse marker arrays for analysis of transmural myocardial mechanics
    Open this publication in new window or tab >>Nonhomogeneous strain from sparse marker arrays for analysis of transmural myocardial mechanics
    2007 (English)In: Journal of Biomechanical Engineering, ISSN 0148-0731, E-ISSN 1528-8951, Vol. 129, no 4, p. 603-610Article in journal (Refereed) Published
    Abstract [en]

    Background: Knowledge of normal cardiac kinematics is important when attempting to understand the mechanisms that impair the contractile function of the heart during disease. The complex kinematics of the heart can be studied by inserting radiopaque markers in the cardiac wall and study the pumping heart with biplane cineradiography. In order to study the local strain, the bead array was developed where small radiopaque beads are inserted along three columns transmurally in the left ventricle. Method: This paper suggests a straightforward method for strain computation, based on polynomial least-squares fitting and tailored for combined marker and bead array analyses. Results: This polynomial method gives small errors for a realistic bead array on an analytical test case. The method delivers an explicit expression of the Lagrangian strain tensor as a polynomial function of the coordinates of material points in the reference configuration. The method suggested in this paper is validated with analytical strains on a deforming cylinder resembling the heart, compared to a previously suggested finite element method, and applied to in vivo ovine data. The errors in the estimated strain components are shown to remain unchanged on an analytical test case when evaluating the effects of one missing bead. In conclusion, the proposed strain computation method is accurate and robust, with errors smaller or comparable to the current gold standard when applied on an analytical test case.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-41891 (URN)10.1115/1.2746385 (DOI)000248737000016 ()59323 (Local ID)59323 (Archive number)59323 (OAI)
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
    3. Strain based estimation of time dependent transmural myocardial architecture in the ovine heart
    Open this publication in new window or tab >>Strain based estimation of time dependent transmural myocardial architecture in the ovine heart
    2010 (English)In: Biomechanics and Modeling in Mechanobiology, ISSN 1617-7959, E-ISSN 1617-7940, Vol. 10, no 4, p. 521-528Article in journal (Refereed) Published
    Abstract [en]

    Left ventricular myofibers are connected by an extensive extracellular collagen matrix to form myolaminar sheets. Histological cardiac tissue studies have previously observed a pleated transmural distribution of sheets in the ovine heart, alternating sign of the sheet angle from epicardium to endocardium. The present study investigated temporal variations in myocardial fiber and sheet architecture during the cardiac cycle. End diastolic histological measurements made at subepicardium, midwall and subendocardium at an anterior-basal and a lateral-equatorial region of the ovine heart, combined with transmural myocardial Lagrangian strains, showed that the sheet angle but not the fiber angle varied temporally throughout the cardiac cycle. The magnitude of the sheet angle decreased during systole at all transmural depths at the anterior-basal site and at midwall and subendocardium depths at the lateral-equatorial site, making the sheets more parallel to the radial axis. These results support a previously suggested accordion-like wall thickening mechanism of the myocardial sheets.

    Place, publisher, year, edition, pages
    SpringerLink, 2010
    Keywords
    Cardiac mechanics; transmural; sheets; wall thickening; myocardium
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-60199 (URN)10.1007/s10237-010-0252-4 (DOI)20821245 (PubMedID)
    Available from: 2010-10-07 Created: 2010-10-07 Last updated: 2017-12-12Bibliographically approved
    4. Transmural Strains in the Ovine Left Ventricular Lateral Wall During Diastolic Filling
    Open this publication in new window or tab >>Transmural Strains in the Ovine Left Ventricular Lateral Wall During Diastolic Filling
    Show others...
    2009 (English)In: JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME, ISSN 0148-0731, Vol. 131, no 6Article in journal (Refereed) Published
    Abstract [en]

    Rapid early diastolic left ventricular (LV) filling requires a highly compliant chamber immediately after systole, allowing inflow at low driving pressures. The transmural LV deformations associated with such filling are not completely understood. We sought to characterize regional transmural LV strains during diastole, with focus on early filling, in ovine hearts at 1 week and 8 weeks after myocardial marker implantation. In seven normal sheep hearts, 13 radiopaque markers were inserted to silhouette the LV chamber and a transmural beadset was implanted into the lateral equatorial LV wall to measure transmural strains. Four-dimensional marker dynamics were obtained 1 week and 8 weeks thereafter with biplane videofluoroscopy in closed-chest, anesthetized animals. LV transmural strains in both cardiac and fiber-sheet coordinates were studied from filling onset to the end of early filling (EOEF, 100 ms after filling onset) and at end diastole. At the 8 week study, subepicardial circumferential strain (E-CC) had reached its final value already at EOEF, while longitudinal and radial strains were nearly zero at this time. Subepicardial E-CC and fiber relengthening (E-ff) at EOEF were reduced to 1 compared with 8 weeks after surgery (E-CC:0.02 +/- 0.01 to 0.08 +/- 0.02 and E-ff:0.00 +/- 0.01 to 0.03 +/- 0.01, respectively, both P < 0.05). Subepicardial E-CC during early LV filling was associated primarily with fiber-normal and sheet-normal shears at the 1 week study, but to all three fiber-sheet shears and fiber relengthening at the 8 week study. These changes in LV subepicardial mechanics provide a possible mechanistic basis for regional myocardial lusitropic function, and may add to our understanding of LV myocardial diastolic dysfunction.

    Keywords
    biomechanics, biomedical measurement, cardiology, diagnostic radiography, medical disorders, strain measurement
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-18556 (URN)10.1115/1.3118774 (DOI)
    Available from: 2009-06-01 Created: 2009-06-01 Last updated: 2016-03-14
    5. Temporal 3D Lagrangian strain from 2D slice followed cine DENSE MRI
    Open this publication in new window or tab >>Temporal 3D Lagrangian strain from 2D slice followed cine DENSE MRI
    Show others...
    2012 (English)In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 32, no 2, p. 139-144Article in journal (Refereed) Published
    Abstract [en]

    A quantitative analysis of myocardial mechanics is fundamental to the understanding of cardiac function, diagnosis of heart disease and assessment of therapeutic intervention. In the clinical situation, where limited scan time often is important, a detailed analysis of the myocardium in a specific region might be more applicable than a full 3D measurement of the entire left ventricle. This paper presents a method to obtain temporal evolutions of transmural 3D Lagrangian strains from two intersecting 2D planes of slice followed cine displacement encoding with stimulated echoes (DENSE) data using a bilinear-cubic polynomial element to resolve strain from the displaced myocardial positions. The method demonstrates accurate results when validated in an analytical model, and has been applied to in vivo data acquired on a 3 T magnetic resonance (MR) system from a healthy volunteer to quantify systolic strains at the anterior-basal region of left ventricular myocardium. The in vivo results agree within experimental accuracy with values reported in the literature.

    Place, publisher, year, edition, pages
    Wiley-Blackwell, 2012
    Keywords
    Myocardium; kinematics; magnetic resonance; transmural
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-60200 (URN)10.1111/j.1475-097X.2011.01068.x (DOI)000299734400010 ()
    Available from: 2010-10-07 Created: 2010-10-07 Last updated: 2017-12-12
    6. Myocardial strains from 3D DENSE magnetic resonance imaging
    Open this publication in new window or tab >>Myocardial strains from 3D DENSE magnetic resonance imaging
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The ability to measure and quantify myocardial motion and deformation provides a useful tool to assist in the diagnosis, prognosis and management of heart disease. The recent development of magnetic resonance imaging methods, such as harmonic phase and displacement encoding with stimulated echoes (DENSE), make detailed non-invasive 3D transmural kinematic analyses of human myocardium possible in the clinic and for research purposes. As data acquisition technologies improve, quantification methods for cardiac kinematics need to be adapted and validated on the new types of data. In the present paper, a previously presented polynomial method for cardiac strain quantification is extended to quantify 3D strains from DENSE magnetic resonance imaging data. The method yields accurate results when validated against an analytical standard, and is applied to in vivo data from a healthy  human heart. The polynomial field is capable of resolving the measured material positions from the in vivo data, and the obtained in vivo strains agree

    Keywords
    Strain, 3D, myocardium, DENSE, transmural
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-60201 (URN)
    Available from: 2010-10-07 Created: 2010-10-07 Last updated: 2016-03-14
  • 7.
    Kindberg, Katarina
    Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation. Linköping University, The Institute of Technology.
    Modelling of strain tensors in cardiac kinematics2006Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The heart wall consists of three distinct layers: the inner endocardium, the middle myocardium and the outer epicardium. The myocardium is the functional tissue that endows the heart with its ability to pump blood, and consists primarily of locally parallel muscle fibers. The orientation of these muscle fibers change with position in the wall. The myofibers have been shown to be arranged parallel in sheets that are rotated around the fiber direction relative to the radial direction of the left ventricle. During a cardiac beat there are local shortenings and lengthenings in the myocardium, both within and between myolaminar sheets. The mechanism by which the local shortening or lengthening is translated into the large and complex motions of the ventricle has to be studied on a local level, by studying deformation. A parameter that describes deformation is strain. The scope of the current project is to perform detailed studies of cardiac strain, particularly during diastole. There exist several definitions of strain tensors and the focus in this project is on the Lagrangian strain tensor.

    The myocardial bead array gives kinematic measures of the myocardium toestimate strain in the left ventricular wall of the pumping heart. During surgery, radiopaque beads are inserted into the myocardium along three transmural columns, with typically four to six beads in each column. The 4D coordinates of the beads are acquired with high resolution using time-resolved biplane cineradiography.

    This thesis presents a method for strain estimation from myocardial coordinate data. This strain estimation method is tailored for the transmural bead array and fits a polynomial to the bead coordinates. A benefit with the polynomial method is its ability to avoid loss of accuracy for the case of a missing bead, e.g. due to problems sometimes encountered during surgery or during the recovery period. The polynomial strain estimation method is applied to coordinate data from a transmural bead array to quantify diastolic myocardial strain in the ovine heart. This reveals transmural strain inhomogeneities during diastole in the ovine heart.

    List of papers
    1. Nonhomogeneous strain from sparse marker arrays for analysis of transmural myocardial mechanics
    Open this publication in new window or tab >>Nonhomogeneous strain from sparse marker arrays for analysis of transmural myocardial mechanics
    2007 (English)In: Journal of Biomechanical Engineering, ISSN 0148-0731, E-ISSN 1528-8951, Vol. 129, no 4, p. 603-610Article in journal (Refereed) Published
    Abstract [en]

    Background: Knowledge of normal cardiac kinematics is important when attempting to understand the mechanisms that impair the contractile function of the heart during disease. The complex kinematics of the heart can be studied by inserting radiopaque markers in the cardiac wall and study the pumping heart with biplane cineradiography. In order to study the local strain, the bead array was developed where small radiopaque beads are inserted along three columns transmurally in the left ventricle. Method: This paper suggests a straightforward method for strain computation, based on polynomial least-squares fitting and tailored for combined marker and bead array analyses. Results: This polynomial method gives small errors for a realistic bead array on an analytical test case. The method delivers an explicit expression of the Lagrangian strain tensor as a polynomial function of the coordinates of material points in the reference configuration. The method suggested in this paper is validated with analytical strains on a deforming cylinder resembling the heart, compared to a previously suggested finite element method, and applied to in vivo ovine data. The errors in the estimated strain components are shown to remain unchanged on an analytical test case when evaluating the effects of one missing bead. In conclusion, the proposed strain computation method is accurate and robust, with errors smaller or comparable to the current gold standard when applied on an analytical test case.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-41891 (URN)10.1115/1.2746385 (DOI)000248737000016 ()59323 (Local ID)59323 (Archive number)59323 (OAI)
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
    2. Spatial and Temporal Inhomogeneity of Left Ventricular Myocardial Transmural Strains During Diastole
    Open this publication in new window or tab >>Spatial and Temporal Inhomogeneity of Left Ventricular Myocardial Transmural Strains During Diastole
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Rapid early filling requires a rapid shift to a very compliant left ventricle immediately after systole, allowing filling at low driving pressures. This compliance shift is manifested as changes in transmural strains: however its mechanistic basis is incompletely understood. Seven adult Dorsett hybrid sheep were anesthetized and radiopaque markers were surgically implanted to silhouette the LV chamber. Three transmural columns of four beads each were implanted into the lateral equatorial LV wall. Eight weeks after surgery, biplane videofluoroscopic images of all radiopaque markers were acquired at 60 Hz horn dosed-chest anesthetized animals. After data acquisition, hearts were arrested at the end-diastolic pressure aud quantitative hist.ology was used to determine fiber and sheet angles. Lagrangian strains in cardiac and liber-sheet coordinates were computed at end of early filling and end diastole with filling onset as reference at three transmural depths. Rapid early filling was dominated by subepicardial circumferential stretching (ECC=0.08±0.02) and fiber lengthening (Eƒƒ=0.03±0.01), midwall circumferential stretching (ECC=0.07±0.02), and subendocardial wall thinning (ERR=-0.05±0.01). Subepicardial strains achieved their ED values during early diastole, while mid wall and subendocardial straius reset during late diastole. Sheet-normal shear strain was a dominant contributor to wall thinning during diastole.

    Keywords
    cardiac strains, fiber-sheet strains, sheep, LV filling
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-100800 (URN)
    Available from: 2013-11-12 Created: 2013-11-12 Last updated: 2013-11-12
  • 8.
    Kindberg, Katarina
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics . Linköping University, The Institute of Technology.
    Carlhäll, Carljohan
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics . Linköping University, The Institute of Technology.
    Nguyen, T C
    Stanford University.
    Cheng, A
    Stanford University.
    Langer, F
    Stanford University.
    Rodriguez, F
    Stanford University.
    Daughters, G T
    Stanford University.
    Miller, D C
    Stanford University.
    Jr Ingels, N B
    Stanford University.
    Transmural Strains in the Ovine Left Ventricular Lateral Wall During Diastolic Filling2009In: JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME, ISSN 0148-0731, Vol. 131, no 6Article in journal (Refereed)
    Abstract [en]

    Rapid early diastolic left ventricular (LV) filling requires a highly compliant chamber immediately after systole, allowing inflow at low driving pressures. The transmural LV deformations associated with such filling are not completely understood. We sought to characterize regional transmural LV strains during diastole, with focus on early filling, in ovine hearts at 1 week and 8 weeks after myocardial marker implantation. In seven normal sheep hearts, 13 radiopaque markers were inserted to silhouette the LV chamber and a transmural beadset was implanted into the lateral equatorial LV wall to measure transmural strains. Four-dimensional marker dynamics were obtained 1 week and 8 weeks thereafter with biplane videofluoroscopy in closed-chest, anesthetized animals. LV transmural strains in both cardiac and fiber-sheet coordinates were studied from filling onset to the end of early filling (EOEF, 100 ms after filling onset) and at end diastole. At the 8 week study, subepicardial circumferential strain (E-CC) had reached its final value already at EOEF, while longitudinal and radial strains were nearly zero at this time. Subepicardial E-CC and fiber relengthening (E-ff) at EOEF were reduced to 1 compared with 8 weeks after surgery (E-CC:0.02 +/- 0.01 to 0.08 +/- 0.02 and E-ff:0.00 +/- 0.01 to 0.03 +/- 0.01, respectively, both P < 0.05). Subepicardial E-CC during early LV filling was associated primarily with fiber-normal and sheet-normal shears at the 1 week study, but to all three fiber-sheet shears and fiber relengthening at the 8 week study. These changes in LV subepicardial mechanics provide a possible mechanistic basis for regional myocardial lusitropic function, and may add to our understanding of LV myocardial diastolic dysfunction.

  • 9.
    Kindberg, Katarina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Cheng, A
    Langer, F
    Rodriguez, F
    Criscione, JC
    Daughters, GT
    Miller, DC
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Ingels, NB
    Spatial and temporal inhomogeneity of transmural LV myocardial strains during diastole2006In: Experimental Biology,2006, 2006, p. A1410-A1410Conference paper (Other academic)
  • 10.
    Kindberg, Katarina
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation. Linköping University, The Institute of Technology.
    Cheng, A.
    Langer, F.
    Rodriguez, F.
    Daughters, G. T.
    Miller, D. C.
    Ingels Jr., N. B.
    Karlsson, M.
    Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation. Linköping University, The Institute of Technology.
    Spatial and Temporal Inhomogeneity of Left Ventricular Myocardial Transmural Strains During DiastoleManuscript (preprint) (Other academic)
    Abstract [en]

    Rapid early filling requires a rapid shift to a very compliant left ventricle immediately after systole, allowing filling at low driving pressures. This compliance shift is manifested as changes in transmural strains: however its mechanistic basis is incompletely understood. Seven adult Dorsett hybrid sheep were anesthetized and radiopaque markers were surgically implanted to silhouette the LV chamber. Three transmural columns of four beads each were implanted into the lateral equatorial LV wall. Eight weeks after surgery, biplane videofluoroscopic images of all radiopaque markers were acquired at 60 Hz horn dosed-chest anesthetized animals. After data acquisition, hearts were arrested at the end-diastolic pressure aud quantitative hist.ology was used to determine fiber and sheet angles. Lagrangian strains in cardiac and liber-sheet coordinates were computed at end of early filling and end diastole with filling onset as reference at three transmural depths. Rapid early filling was dominated by subepicardial circumferential stretching (ECC=0.08±0.02) and fiber lengthening (Eƒƒ=0.03±0.01), midwall circumferential stretching (ECC=0.07±0.02), and subendocardial wall thinning (ERR=-0.05±0.01). Subepicardial strains achieved their ED values during early diastole, while mid wall and subendocardial straius reset during late diastole. Sheet-normal shear strain was a dominant contributor to wall thinning during diastole.

  • 11.
    Kindberg, Katarina
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics . Linköping University, The Institute of Technology.
    Haraldsson, Henrik
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Sigfridsson, Andreas
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Engvall, Jan
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ingels, Neil B.
    dDepartment of Cardiothoracic Surgery, School of Medicine, Stanford University, Stanford, CA 94305, USA.
    Ebbers, Tino
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics . Linköping University, The Institute of Technology.
    Myocardial strains from 3D DENSE magnetic resonance imagingManuscript (preprint) (Other academic)
    Abstract [en]

    The ability to measure and quantify myocardial motion and deformation provides a useful tool to assist in the diagnosis, prognosis and management of heart disease. The recent development of magnetic resonance imaging methods, such as harmonic phase and displacement encoding with stimulated echoes (DENSE), make detailed non-invasive 3D transmural kinematic analyses of human myocardium possible in the clinic and for research purposes. As data acquisition technologies improve, quantification methods for cardiac kinematics need to be adapted and validated on the new types of data. In the present paper, a previously presented polynomial method for cardiac strain quantification is extended to quantify 3D strains from DENSE magnetic resonance imaging data. The method yields accurate results when validated against an analytical standard, and is applied to in vivo data from a healthy  human heart. The polynomial field is capable of resolving the measured material positions from the in vivo data, and the obtained in vivo strains agree

  • 12.
    Kindberg, Katarina
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Haraldsson, Henrik
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Sigfridsson, Andreas
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Engvall, Jan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Ingels, Neil B.
    Stanford University, CA, USA .
    Ebbers, Tino
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Department of Science and Technology, Media and Information Technology.
    Karlsson, Matts
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Myocardial strains from 3D displacement encoded magnetic resonance imaging2012In: BMC Medical Imaging, ISSN 1471-2342, E-ISSN 1471-2342, Vol. 12, no 9Article in journal (Refereed)
    Abstract [en]

    Background

    The ability to measure and quantify myocardial motion and deformation provides a useful tool to assist in the diagnosis, prognosis and management of heart disease. The recent development of magnetic resonance imaging methods, such as harmonic phase analysis of tagging and displacement encoding with stimulated echoes (DENSE), make detailed non-invasive 3D kinematic analyses of human myocardium possible in the clinic and for research purposes. A robust analysis method is required, however.

    Methods

    We propose to estimate strain using a polynomial function which produces local models of the displacement field obtained with DENSE. Given a specific polynomial order, the model is obtained as the least squares fit of the acquired displacement field. These local models are subsequently used to produce estimates of the full strain tensor.

    Results

    The proposed method is evaluated on a numerical phantom as well as in vivo on a healthy human heart. The evaluation showed that the proposed method produced accurate results and showed low sensitivity to noise in the numerical phantom. The method was also demonstrated in vivo by assessment of the full strain tensor and to resolve transmural strain variations.

    Conclusions

    Strain estimation within a 3D myocardial volume based on polynomial functions yields accurate and robust results when validated on an analytical model. The polynomial field is capable of resolving the measured material positions from the in vivo data, and the obtained in vivo strains values agree with previously reported myocardial strains in normal human hearts.

  • 13.
    Kindberg, Katarina
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Haraldsson, Henrik
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Sigfridsson, Andreas
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Sakuma, Hajime
    Department of Radiology, Mie University, 2-174 Edobashi, Tsu, Mie 514-8507, Japan.
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Temporal 3D Lagrangian strain from 2D slice followed cine DENSE MRI2012In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 32, no 2, p. 139-144Article in journal (Refereed)
    Abstract [en]

    A quantitative analysis of myocardial mechanics is fundamental to the understanding of cardiac function, diagnosis of heart disease and assessment of therapeutic intervention. In the clinical situation, where limited scan time often is important, a detailed analysis of the myocardium in a specific region might be more applicable than a full 3D measurement of the entire left ventricle. This paper presents a method to obtain temporal evolutions of transmural 3D Lagrangian strains from two intersecting 2D planes of slice followed cine displacement encoding with stimulated echoes (DENSE) data using a bilinear-cubic polynomial element to resolve strain from the displaced myocardial positions. The method demonstrates accurate results when validated in an analytical model, and has been applied to in vivo data acquired on a 3 T magnetic resonance (MR) system from a healthy volunteer to quantify systolic strains at the anterior-basal region of left ventricular myocardium. The in vivo results agree within experimental accuracy with values reported in the literature.

  • 14.
    Kindberg, Katarina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Ingels, NB
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Transmural inhomogeneity of cardiac strains during filling2006In: Cardiovascular System Dynamics Society,2006, 2006Conference paper (Other academic)
    Abstract [en]

      

  • 15.
    Kindberg, Katarina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Cardiac wall strain variations due to compressibiity2004In: Nordic Seminar on Computational Mechanics,2004, 2004Conference paper (Refereed)
  • 16.
    Kindberg, Katarina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Mitral valve opening in the failing heart2005In: Nordic Baltic Conference Biomedical Engineering and Medical Physics,2005, Umeå: IFMBE , 2005, p. 91-Conference paper (Refereed)
  • 17.
    Kindberg, Katarina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Spatial differences in cardiac strains during filling2006In: The 19th Nordic Seminar on Computational Mechanics,2006, 2006, p. 59-Conference paper (Refereed)
    Abstract [en]

      

  • 18.
    Kindberg, Katarina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Strain computation with myocardial markers2005In: Svenska Mekanikdagarna 2005,2005, 2005, p. 12-12Conference paper (Other academic)
  • 19.
    Kindberg, Katarina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Transmural myocardial strain distribution - theoretical results and IN VIVO data2005In: 13th Nordic Baltic Conference Biomedical Engineering and Meical Physics,2005, Umeå: IFMBE , 2005, p. 279-Conference paper (Refereed)
  • 20.
    Kindberg, Katarina
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation. Linköping University, The Institute of Technology.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation.
    Ingels, NB Jr
    Stanford University Medical Center.
    Criscione, JC
    Texas AM University.
    Nonhomogeneous strain from sparse marker arrays for analysis of transmural myocardial mechanics2007In: Journal of Biomechanical Engineering, ISSN 0148-0731, E-ISSN 1528-8951, Vol. 129, no 4, p. 603-610Article in journal (Refereed)
    Abstract [en]

    Background: Knowledge of normal cardiac kinematics is important when attempting to understand the mechanisms that impair the contractile function of the heart during disease. The complex kinematics of the heart can be studied by inserting radiopaque markers in the cardiac wall and study the pumping heart with biplane cineradiography. In order to study the local strain, the bead array was developed where small radiopaque beads are inserted along three columns transmurally in the left ventricle. Method: This paper suggests a straightforward method for strain computation, based on polynomial least-squares fitting and tailored for combined marker and bead array analyses. Results: This polynomial method gives small errors for a realistic bead array on an analytical test case. The method delivers an explicit expression of the Lagrangian strain tensor as a polynomial function of the coordinates of material points in the reference configuration. The method suggested in this paper is validated with analytical strains on a deforming cylinder resembling the heart, compared to a previously suggested finite element method, and applied to in vivo ovine data. The errors in the estimated strain components are shown to remain unchanged on an analytical test case when evaluating the effects of one missing bead. In conclusion, the proposed strain computation method is accurate and robust, with errors smaller or comparable to the current gold standard when applied on an analytical test case.

  • 21.
    Kindberg, Katarina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Oom, Charlotte
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Cheng, A
    Langer, F
    Rodriquez, F
    Daughters, GT
    Miller, DC
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Ingels, NB
    Early postoperative blunting of rapid diastolic subepicardial fiber lengthening and left ventricular circumferential expansion2006In: American Heart Assiciations Scientific Sessions,2006, 2006, p. 353-353Conference paper (Other academic)
    Abstract [en]

        

  • 22.
    Kindberg, Katarina
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Oom, Charlotte
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Ingels, Neil B.
    Department of Cardiothoracic Surgery, School of Medicine, Stanford University, Stanford, CA 94305, USA.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Strain based estimation of time dependent transmural myocardial architecture in the ovine heart2010In: Biomechanics and Modeling in Mechanobiology, ISSN 1617-7959, E-ISSN 1617-7940, Vol. 10, no 4, p. 521-528Article in journal (Refereed)
    Abstract [en]

    Left ventricular myofibers are connected by an extensive extracellular collagen matrix to form myolaminar sheets. Histological cardiac tissue studies have previously observed a pleated transmural distribution of sheets in the ovine heart, alternating sign of the sheet angle from epicardium to endocardium. The present study investigated temporal variations in myocardial fiber and sheet architecture during the cardiac cycle. End diastolic histological measurements made at subepicardium, midwall and subendocardium at an anterior-basal and a lateral-equatorial region of the ovine heart, combined with transmural myocardial Lagrangian strains, showed that the sheet angle but not the fiber angle varied temporally throughout the cardiac cycle. The magnitude of the sheet angle decreased during systole at all transmural depths at the anterior-basal site and at midwall and subendocardium depths at the lateral-equatorial site, making the sheets more parallel to the radial axis. These results support a previously suggested accordion-like wall thickening mechanism of the myocardial sheets.

  • 23.
    Kindberg, Katarina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Oom, Charlotte
    Linköping University, Department of Biomedical Engineering.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Cardiac Kinematics - The coupling between local strain and global left ventricular volume2006Report (Other academic)
  • 24.
    Oom, Charlotte
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Kindberg, Katarina
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Ingels, NB
    Temporal changes in sheet architecture during systole2006In: Cardiovascular System Dynamics Society,2006, 2006Conference paper (Other academic)
  • 25.
    Oom, Charlotte
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Kindberg, Katarina
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Ingels, NB
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Temporal changes in sheet architecture during systole2006In: The 19th Nordic Seminar on Computational Mechanics,2006, 2006, p. 63-Conference paper (Refereed)
    Abstract [en]

        

  • 26.
    Oom, Charlotte
    et al.
    Linköping University, Department of Biomedical Engineering.
    Kindberg, Katarina
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Cardiac Kinematics - Mapping of variations in laminar fiber and sheet architecture during the cardiac cycle2006Report (Other academic)
1 - 26 of 26
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