About

Paul E. Barbone is a Professor of Theoretical Acoustics & Applied Mechanics at Boston University. He is affiliated with the Department of Mechanical Engineering and the Division of Material Science & Engineering. His research profile and curriculum vitae are available through his university webpage. The page was last updated in November 2008, and it provides contact information including his email and phone number.

Research topics

• Physics
• Materials science
• Computer Science
• Medicine
• Acoustics
• Composite material
• Biomedical engineering
• Pathology
• Mechanics
• Optics
• Mathematics
• Biology
• Radiology
• Anatomy
• Computer vision
• Statistics

Selected publications

• Characterizing dispersion in bovine liver using ARFI-based shear wave rheometry

  Biomedical Physics & Engineering Express · 2024-08-05

  articleOpen access

  Abstract Background: Dispersion presents both a challenge and a diagnostic opportunity in shear wave elastography (SWE). Shear Wave Rheometry (SWR) is an inversion technique for processing SWE data acquired using an acoustic radiation force impulse (ARFI) excitation. The main advantage of SWR is that it can characterize the shear properties of homogeneous soft media over a wide frequency range. Assumptions associated with SWR include tissue homogeneity, tissue isotropy, and axisymmetry of the ARFI excitation). Objective: Evaluate the validity of the SWR assumptions in ex vivo bovine liver. Approach: SWR was used to measure the shear properties of bovine liver tissue as function of frequency over a large frequency range. Assumptions associated with SWR (tissue homogeneity, tissue isotropy, and axisymmetry of the ARFI excitation) were evaluated through measurements performed at multiple locations and probe orientations. Measurements focused on quantities that would reveal violations of the assumptions. Main results: Measurements of shear properties were obtained over the 25–250 Hz range, and showed a 4-fold increase in shear storage modulus (from 1 to 4 kPa) and over a 10-fold increase in the loss modulus (from 0.2 to 3 kPa) over that decade-wide frequency range. Measurements under different conditions were highly repeatable, and model error was low in all cases. Significance and Conclusion: SWR depends on modeling the ARFI-induced shear wave as a full vector viscoelastic shear wave resulting from an axisymmetric source; it is agnostic to any specific rheological model. Despite this generality, the model makes three main simplifying assumptions. These results show that the modeling assumptions used in SWR are valid in bovine liver over a wide frequency band.

  PublisherOA PDFDOI

• An improved image analysis method for micropattern traction microscopy: dot tracking and traction force calculation script protocols v1

  2024-04-10

  preprintOpen access

  The dot tracking script takes timelapse images of fluorescent micropatterns and determines the frame-by-frame displacement of each fluorescent dot. From these displacement values, the traction force calculation script calculates the corresponding traction force values using the known material properties of the gel being imaged, as described in Equation 2 of the main text. It can also plot either traction or displacement maps, user’s choice. Final x and y displacement vectors (taken from dot displacement script and thresholded based on the chosen displacement threshold value) are saved to the variables “x_dis_final_thresh” and “y_dis_final_thresh,” and the magnitude of these vectors is saved to “magD.” Unbalanced traction force vectors are saved to “T1” and “T2,” while balanced traction force vectors (for static equilibrium) are saved to “feX” and “feY,” respectively. The magnitudes of the unbalanced and balanced traction force vectors are saved to “magT_UB” and “magT_B,” respectively.

  PublisherOA PDFDOI

• Multiscale theoretical model shows that aging-related mechanical degradation of cortical bone is driven by microstructural changes in addition to porosity

  Journal of the mechanical behavior of biomedical materials/Journal of mechanical behavior of biomedical materials · 2023-07-18 · 3 citations

  articleOpen access
  PublisherOA PDFDOI

• A Force-Matched Approach to Large-Strain Nonlinearity in Elasticity Imaging for Breast Lesion Characterization

  IEEE Transactions on Biomedical Engineering · 2023 · 4 citations

  • Medicine
  • Radiology
  • Biomedical engineering

  OBJECTIVE: Ultrasound elasticity imaging is a class of ultrasound techniques with applications that include the detection of malignancy in breast lesions. Although elasticity imaging traditionally assumes linear elasticity, the large strain elastic response of soft tissue is known to be nonlinear. This study evaluates the nonlinear response of breast lesions for the characterization of malignancy using force measurement and force-controlled compression during ultrasound imaging. METHODS: 54 patients were recruited for this study. A custom force-instrumented compression device was used to apply a controlled force during ultrasound imaging. Motion tracking derived strain was averaged over lesion or background ROIs and matched with compression force. The resulting force-matched strain was used for subsequent analysis and curve fitting. RESULTS: Greater median differences between malignant and benign lesions were observed at higher compressional forces (p-value < 0.05 for compressional forces of 2-6N). Of three candidate functions, a power law function produced the best fit to the force-matched strain. A statistically significant difference in the scaling parameter of the power function between malignant and benign lesions was observed (p-value = 0.025). CONCLUSIONS: We observed a greater separation in average lesion strain between malignant and benign lesions at large compression forces and demonstrated the characterization of this nonlinear effect using a power law model. Using this model, we were able to differentiate between malignant and benign breast lesions. SIGNIFICANCE: With further development, the proposed method to utilize the nonlinear elastic response of breast tissue has the potential for improving non-invasive lesion characterization for potential malignancy.

  PublisherOA PDFDOI

• Corrigendum to ‘Shear wave speed in pressurized soft tissue’ [J. Mech. Phys. Solids, 119 (2018) 60 – 72]

  Journal of the Mechanics and Physics of Solids · 2023-09-15 · 2 citations

  erratum1st authorCorresponding
  PublisherDOI

• Residual-based stabilized formulation for the solution of inverse elliptic partial differential equations

  Computers & Mathematics with Applications · 2020-05-28

  article
  PublisherDOI

• Significance of the Microfluidic Flow Inside the Organ of Corti

  Journal of Biomechanical Engineering · 2020 · 18 citations

  • Physics
  • Mechanics
  • Acoustics

  We study the vibration modes of a short section in the middle turn of the gerbil cochlea including both longitudinal and radial interstitial fluid spaces between the pillar cells (PC) and the sensory hair cells to determine the role of the interstitial fluid flow within the organ of corti (OoC). Three detailed finite element (FE) models of the cochlear short section (CSS) are studied. In model 1, the CSS is without fluids; model 2 includes the OoC fluid, but not the exterior scalae fluids; and model 3 is the CSS with both scalae and OoC fluids. We find that: (1) the fundamental mode shape of models 1 or 3 is similar to the classical basilar membrane (BM) bending mode that includes pivoting of the arch of corti, and hence determines the low frequency vibrational mode shape of the cochlea in the presence of the cochlear wave. (2) The fundamental mode shape of model 2 is characterized by a cross-sectional shape change similar to the passive response of the cochlea. This mode shape includes a tilting motion of the inner hair cell (IHC) region, a fluid motion within the tunnel of corti (ToC) in the radial direction and along the OoC, and a bulging motion of the reticular lamina (RL) above the outer hair cell (OHC). Each of these motions provides a plausible mode of excitation of the sensory hair cells. (3) The higher vibrational modes of model 1 are similar to the electrically evoked response within the OoC and suggests that the higher vibrational modes are responsible for the active response of the cochlea. We also observed that the fluid flow through the OoC interstitial space is significant, and the model comparison suggests that the OoC fluid contributes to the biphasic BM motion seen in electrical stimulation experiments. The effect of fluid viscosity on cilium deflection was assessed by performing a transient analysis to calculate the cilium shearing gain. The gain values are found to be within the range of experimentally measured values reported by Dallos et al. (1996, The Cochlea, Springer-Verlag, New York).

  PublisherOA PDFDOI

• Repeatability of Linear and Nonlinear Elastic Modulus Maps From Repeat Scans in the Breast

  IEEE Transactions on Medical Imaging · 2020 · 8 citations

  • Computer Science
  • Materials science
  • Biomedical engineering

  Compression elastography allows the precise measurement of large deformations of soft tissue in vivo. From an image sequence showing tissue undergoing large deformation, an inverse problem for both the linear and nonlinear elastic moduli distributions can be solved. As part of a larger clinical study to evaluate nonlinear elastic modulus maps (NEMs) in breast cancer, we evaluate the repeatability of linear and nonlinear modulus maps from repeat measurements. Within the cohort of subjects scanned to date, 20 had repeat scans. These repeated scans were processed to evaluate NEM repeatability. In vivo data were acquired by a custom-built, digitally controlled, uniaxial compression device with force feedback from the pressure-plate. RF-data were acquired using plane-wave imaging, at a frame-rate of 200 Hz, with a ramp-and-hold compressive force of 8N, applied at 8N/sec. A 2D block-matching algorithm was used to obtain sample-level displacement fields which were then tracked at subsample resolution using 2D cross correlation. Linear and nonlinear elasticity parameters in a modified Veronda-Westmann model of tissue elasticity were estimated using an iterative optimization method. For the repeated scans, B-mode images, strain images, and linear and nonlinear elastic modulus maps are measured and compared. Results indicate that when images are acquired in the same region of tissue and sufficiently high strain is used to recover nonlinearity parameters, then the reconstructed modulus maps are consistent.

  PublisherOA PDFDOI

• Repeatability of linear and nonlinear quantitative compression elastography in the breast

  The Journal of the Acoustical Society of America · 2019-03-01

  article1st authorCorresponding

  Compression elastography allows the precise measurement of large deformations of soft tissue in vivo. From a measured large deformation, an inverse problem for both the linear and nonlinear elastic moduli distributions can be solved. As part of a larger clinical study to evaluate NEMs in breast cancer, we evaluate the repeatability of linear and nonlinear modulus maps from repeat measurements. Within the cohort of 31 subjects scanned to date, several had repeated scans. These repeated scans were processed to evaluate NEM repeatability. In vivo data were acquired by a custom, digitally controlled, uniaxial compression device with force feedback. RF-data were acquired using plane wave imaging, at a frame-rate of 200 Hz, with a ramp-and-hold compressive force of 8N, applied at 8 N/s. A two-dimensional (2D) block-matching algorithm was used to obtain sample-level displacement fields which were then tracked at subsample resolution using 2D cross correlation. Linear and nonlinear elasticity parameters in the Blatz model of tissue elasticity are estimated using iterative optimization. Repeatability between both modes and elastic modulus maps is measured and compared. Preliminary results indicate that when images are acquired in the same region of tissue, the modulus maps are consistent. [Work supported by NIH R01CA195527.]

  PublisherDOI

• Frequency content of shear wave pulses excited by acoustic radiation force

  The Journal of the Acoustical Society of America · 2019-10-01 · 1 citations

  article1st authorCorresponding

  Ultrasound shear wave elastography uses shear waves to infer the viscoelastic properties of soft tissues. Since soft tissues tend to exhibit dispersive behavior, it is important to standardize the frequency at which measurements are reported. Shear wave pulses excited by acoustic radiation force in different materials, however, do not have the same frequency content, even if the radiation force pulse has precisely the same characteristics. Here, we present a simple model for shear wave pulse creation by acoustic radiation force. This model explains the frequency content of the acoustic radiation force pulse and can therefore be used to design radiation forcing parameters to obtain a desired frequency content in a given material. To derive our model, we use separation of time-scales to show that the shear wave pulse propagation may be treated as an initial value problem. The combination of the (particle) initial velocity distribution and the tissue mechanical properties determines the resulting frequency content of the shear wave pulse.

  PublisherDOI

Recent grants

• SI2:SSE-Collaborative Research: Advanced Software Infrastructure for Biomechanical Inverse Problems

  NSF · $240k · 2012–2016

• NIH Grant F33CA090045

  NIH · $46k

Frequent coauthors

• Assad A. Oberai

  82 shared

• Isaac Harari

  Tel Aviv University

  35 shared

• Jeffrey C. Bamber

  Royal Marsden NHS Foundation Trust

  30 shared

• Timothy J. Hall

  18 shared

• Olalekan A. Babaniyi

  16 shared

• Sanjay S. Yengul

  Boston University

  11 shared

• Nigel L. Bush

  Institute of Cancer Research

  11 shared

• Carlos E. Rivas

  University of Cuenca

  10 shared

Awards & honors

• Fellow, American Institute for Medical and Biological Engine…
• Fellow, Acoustical Society of America, 2007