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Introduction: No data are available on the diagnostic algorithms recommended by guidelines for the assessment of diastolic dysfunction (DD) in patients with arterial hypertension., Aim: To fill this gap, we evaluated diastolic function in hypertensive patients with and without LVH matched with healthy subjects by applying 2016 American Society of Echocardiography-European Association of Cardiovascular Imaging Guidelines for the evaluation of LV diastolic function., Methods: 717 healthy and hypertensives with normal LV ejection fraction and with and without LV hypertrophy (LVH), matched 1:1:1 from two prospective registries, represented the study population., Results: By applying algorithm A, indeterminate pattern was found in 0.4% of healthy, in 6.3% of hypertensives without LVH, and in 21% with LVH (overall p < 0.05 vs. healthy). DD was absent in healthy, however present in 2 and 8% of hypertensives without and with LVH (p = 0.06 and p = 0.001 vs. healthy, respectively). By applying algorithm B, no cases of indeterminate pattern were found. DD was observed in 2.9% of healthy, 7 and 10.5% of hypertensives without and with LVH (p < 0.05 vs. healthy)., Conclusions: The use of algorithm A should be limited only to truly normal subjects, whereas algorithm B should be applied to all patients with hypertension, even without comorbidities and irrespective of LVH., (© 2024. The Author(s).)

Reconstructing sound-speed maps from the limited view offered by a linear array of ultrasonic sensors has been a long-standing challenge in medical diagnostics and nondestructive evaluation. Because of the limited range of angles that can be used to interrogate the volume beneath the array, the inverse problem of retrieving sound-speed maps from scattering measurements is highly ill-posed. The missing angles cause significant artifacts that degrade the image by altering the values of sound speed and producing ghost features. This paper introduces the virtual image space component iterative technique (VISCIT), which addresses the limited-view problem by introducing a new regularization technique which iteratively compensates for the missing components by applying an adaptive threshold to the reconstruction. The effectiveness of the method in yielding high-accuracy sound-speed maps is demonstrated using a complex numerical phantom and validated experimentally with an agar phantom. It is shown that sound-speed contrast as low as 1.3% is readily detectable, thus paving the way for more sensitive and selective detection of damage precursors and early stage diseases.

Breast ultrasound tomography has the potential to improve the cost, safety, and reliability of breast cancer screening and diagnosis over the gold-standard of mammography. Vital to achieving this potential is the development of imaging algorithms to unravel the complex anatomy of the breast and its mechanical properties. The solution most commonly relied upon is time-of-flight tomography, but this exhibits low resolution due to the presence of diffraction effects. Iterative full-wave inversion methods present one solution to achieve higher resolution, but these are slow and are not guaranteed to converge to the correct solution. Presented here is HARBUT, the hybrid algorithm for robust breast ultrasound tomography, which utilizes the complementary strengths of time-of-flight and diffraction tomography resulting in a direct, fast, robust and accurate high resolution method of reconstructing the sound speed through the breast. The algorithm is shown to produce accurate reconstructions with realistic data from a complex three-dimensional simulation, with masses as small as 4 mm being clearly visible., (© 2011 Acoustical Society of America)

This paper develops, within a general framework that is applicable to rather arbitrary electromagnetic and acoustic remote sensing systems, a theory of time-reversal "MUltiple Signal Classification" (MUSIC)-based imaging of extended (nonpoint-like) scatterers (targets). The general analysis applies to arbitrary remote sensing geometry and sheds light onto how the singular system of the scattering matrix relates to the geometrical and propagation characteristics of the entire transmitter-target-receiver system and how to use this effect for imaging. All the developments are derived within exact scattering theory which includes multiple scattering effects. The derived time-reversal MUSIC methods include both interior sampling, as well as exterior sampling (or enclosure) approaches. For presentation simplicity, particular attention is given to the time-harmonic case where the informational wave modes employed for target interrogation are purely spatial, but the corresponding generalization to broadband fields is also given. This paper includes computer simulations illustrating the derived theory and algorithms.

A new technique for measuring the longitudinal bulk velocity and shear viscosity of a fluid contained inside a pipe without a need for extracting a sample from inside of the pipe is presented. It is based on the measurement of the change of the dispersion properties and attenuation of longitudinal guided modes propagating in the pipe due to the presence of the fluid. The technique to extract longitudinal bulk velocity and shear viscosity is discussed and experimentally demonstrated by measuring both low-viscosity (distilled water and glycerol) and highly viscous fluids. The measured properties of glycerol agreed well with conventional methods and literature data for both the longitudinal bulk velocity (within 0.8%) and the viscosity (within 4%). For highly viscous fluid, the accuracy of the velocity measurement was found to be reduced slightly (within 1%), and the viscosity measurement became more accurate (within 1%).