Elevated brain pulsations in depression: insights from a pooled ultrasound cohort study.

Excessive brain tissue pulsations (BTP), measured by ultrasound, have been associated with depression and are hypothesized to contribute to brain damage in this population at risk for cerebrovascular lesions. However, previous research has been limited by small sample sizes. To address this issue, our study pooled data from three separate investigations, resulting in the largest cohort of depressed participants with BTP measurements to date.

Tumoral and peritumoral vascularization of brain tumours: a study comparing an intraoperative ultrasensitive Doppler and a preoperative first-pass perfusion MRI.

Introduction: Surgery for gliomas can be guided by neuronavigation using magnetic resonance imaging (MRI) and intraoperative B-mode ultrasound. An ultrasensitive Doppler (USD) using plane waves is a new method of microvascularization imaging which can be used intraoperatively and could identify tumoral and peritumoral areas with neoangiogenesis but its value requires evaluation. The aim of this pilot study then was to evaluate the correlations between ultrasound measurements of glioma vascularization (tumoral and peritumoral region) obtained by a USD intraoperatively and first-pass perfusion measurements obtained on preoperative MRI.

Changes in cerebral connectivity and brain tissue pulsations with the antidepressant response to an equimolar mixture of oxygen and nitrous oxide: an MRI and ultrasound study.

Nitrous oxide (NO) has recently emerged as a potential fast-acting antidepressant but the cerebral mechanisms involved in this effect remain speculative. We hypothesized that the antidepressant response to an Equimolar Mixture of Oxygen and Nitrous Oxide (EMONO) would be associated with changes in cerebral connectivity and brain tissue pulsations (BTP). Thirty participants (20 with a major depressive episode resistant to at least one antidepressant and 10 healthy controls-HC, aged 25-50, only females) were exposed to a 1-h single session of EMONO and followed for 1 week.

Multi-layered adaptive neoangiogenesis Intra-Operative quantification (MANIOQ).

Quantification of vascularization volume can provide valuable information for diagnosis and prognosis in vascular pathologies. It can be adapted to inform the surgical management of gliomas, aggressive brain tumors characterized by exuberant sprouting of new blood vessels (neoangiogenesis). Filtered ultrafast Doppler data can provide two main parameters: vascularization index (VI) and fractional moving blood volume (FMBV) that clinically reflect tumor micro vascularization.

Vibration-controlled transient elastography for noninvasive evaluation of liver steatosis.

Background: Nonalcoholic fatty liver disease (NAFLD) refers to a large spectrum of liver disorders and is the most common cause of metabolic liver disease. The current gold standard for diagnosing NAFLD is liver biopsy, which can lead to severe complications.

Purpose: Among the noninvasive diagnostic options, we chose to use a FibroScan and developed an algorithm applying the Voigt rheological model to assess the viscoelastic properties of the liver and evaluate its performance for the diagnosis of steatosis.

Decrease in ultrasound Brain Tissue Pulsations as a potential surrogate marker of response to antidepressant.

Previous cross-sectional studies found excessive Brain Tissue Pulsations (BTP) in mid-life depression, which could constitute a mechanism of brain damage in depression. However, it remains unclear whether successful antidepressant therapy restores BTP amplitudes. In this prospective study, we investigated longitudinal changes in BTP in patients with a major depressive episode (MDE), among responders and non-responders to escitalopram.

Acousto-elasticity of transversely isotropic incompressible soft tissues: characterization of skeletal striated muscle.

Using shear wave elastography, we measure the changes in the wave speed with the stress produced by a striated muscle during isometric voluntary contraction. To isolate the behaviour of an individual muscle from complementary or antagonistic actions of adjacent muscles, we select themuscle, whose sole function is to extend the little finger. To link the wave speed to the stiffness, we develop an acousto-elastic theory for shear waves in homogeneous, transversely isotropic, incompressible solids subject to an uniaxial stress.

Joint Blind Deconvolution and Robust Principal Component Analysis for Blood Flow Estimation in Medical Ultrasound Imaging.

This article addresses the problem of high-resolution Doppler blood flow estimation from an ultrafast sequence of ultrasound images. Formulating the separation of clutter and blood components as an inverse problem has been shown in the literature to be a good alternative to spatio-temporal singular value decomposition (SVD)-based clutter filtering. In particular, a deconvolution step has recently been embedded in such a problem to mitigate the influence of the point spread function (PSF) of the imaging system.

Diffuse shear wave spectroscopy for soft tissue viscoelastic characterization.

In order to limit and slow the development of diseases, they have to be diagnosed early as possible to treat patients in a better and more rapid manner. In this paper, we focus on a noninvasive and quick method based on diffuse fields in elastography to detect diseases that affect the stiffness of organs. To validate our method, a phantom experiment numerically pre-validated is designed.

Left amygdala volume and brain tissue pulsatility are associated with neuroticism: an MRI and ultrasound study.

Brain changes associated with the personality trait of neuroticism have been partly elucidated. While subcortical brain volume changes, especially a larger amygdala, appear consistent in high neuroticism, functional changes, such as cerebral blood flow (CBF) differences, have shown conflicting results, possibly because of the limitations in methods of CBF measurement. In our study, we investigated changes in amygdala volume and CBF-related function associated with neuroticism in healthy and depressed subjects using both conventional magnetic resonance imaging (MRI) measures of brain volume and the innovative technique of ultrasound Tissue Pulsatility Imaging (TPI), which has a high level of detection in measuring brain tissue pulsatility (BTP).

A systematic review of ultrasound imaging and therapy in mental disorders.

Background: Increasing evidence suggests that ultrasound (US) imaging may provide biomarkers and therapeutic options in mental disorders. We systematically reviewed the literature to provide a global overview of the possibilities of US for psychiatry.

Methods: Original English language articles published between January 2000 and September 2019 were identified through databases searching and analyzed to summarize existing evidence according to PRISMA methodology.

When classical music relaxes the brain: An experimental study using Ultrasound Brain Tissue Pulsatility Imaging.

Introduction: Recent evidence suggests that biomechanical parameters of the brain, such as Brain Tissue Pulsatility (BTP), could be involved in emotional reactivity. However, no study has investigated the impact of an emotional task on BTP. We used the ultrasound method of Tissue Pulsatility Imaging (TPI) to assess changes in BTP to exciting and relaxing classical music, in a musical perception task, as a validated paradigm to assess emotional reactivity.

Ultrasound Measures of Brain Pulsatility Correlate with Subcortical Brain Volumes in Healthy Young Adults.

Increasing evidence suggests that brain pulsatility is involved in the pathophysiology of various neurological and psychiatric disorders. However, it remains unclear whether high brain pulsatility is damaging to or protective of the brain in normal conditions, and this could depend on the age of the individual and the methods used to measure brain pulsatility. The goal of our study was to investigate associations between subcortical volumes and brain pulsatility as assessed with ultrasound in healthy young adults using both a conventional method (transcranial Doppler pulsatility index [TCD-PI]) and the innovative method of tissue pulsatility imaging (TPI), which allows a high level of detection of small brain movements (micrometers).

Measurement of shear wave speed dispersion in the placenta by transient elastography: A preliminary ex vivo study.

Background: Placental elasticity may be modified in women with placental insufficiency. Shear wave elastography (SWE) can measure this, using acoustic radiation force, but the safety of its use in pregnant women has not yet been demonstrated. Transient elastography (TE) is a safer alternative, but has not yet been applied to the placenta.

Brain tissue pulsatility mediates cognitive and electrophysiological changes in normal aging: Evidence from ultrasound tissue pulsatility imaging (TPI).

Aging is characterized by a cognitive decline of fluid abilities and is also associated with electrophysiological changes. The vascular hypothesis proposes that brain is sensitive to vascular dysfunction which may accelerate age-related brain modifications and thus explain age-related neurocognitive decline. To test this hypothesis, cognitive performance was measured in 39 healthy participants from 20 to 80 years, using tests assessing inhibition, fluid intelligence, attention and crystallized abilities.

Brain Tissue Pulsatility is Increased in Midlife Depression: a Comparative Study Using Ultrasound Tissue Pulsatility Imaging.

Cerebrovascular disease (CVD) is consistently associated with late-life depression but poorly documented in midlife depression. It can be hypothesized that the relatively low sensitivity of conventional neuroimaging techniques does not allow the detection of subtle CVD in midlife depression. We used tissue pulsatility imaging (TPI), a novel ultrasound (US) neuroimaging technique that has demonstrated good sensitivity to detect changes in the pulsatility of small brain volumes, to identify early and subtle changes in brain vascular function in midlife depression.

Ultrasound Tissue Pulsatility Imaging Suggests Impairment in Global Brain Pulsatility and Small Vessels in Elderly Patients with Orthostatic Hypotension.

Background: Orthostatic hypotension (OH) is highly prevalent in the elderly, and this population can be exposed to serious complications, including falls and cognitive disorders, as well as overall mortality. However, the pathophysiology of OH is still poorly understood, and innovative methods of cerebral blood flow (CBF) assessment have been required to accurately investigate cerebrovascular reactivity in OH.

Objectives: We want to compare brain tissue pulsatility (BTP) changes during an orthostatic challenge in elderly patients over 80 with and without OH.

Ultrasound measurements of brain tissue pulsatility correlate with the volume of MRI white-matter hyperintensity.

White-matter hyperintensity (WMH) is frequently seen in magnetic resonance imaging (MRI), but the complete physiopathology of WMH remains to be elucidated. In this study, we sought to determine whether there is an association between the maximum brain tissue displacement (maxBTD), as assessed by ultrasound, and the WMH, as observed by MRI. Nine healthy women aged 60 to 85 years underwent ultrasound and MRI assessments.

Ultrasound Brain Tissue Pulsatility is decreased in middle aged and elderly type 2 diabetic patients with depression.

We used Tissue Pulsatility Imaging (TPI) to compare the Brain Tissue Pulsatility (BTP) in depressed (n=11) and non-depressed (n=13) type-2 diabetic non-demented patients aged 50 years and older. Both maximum and mean BTP were significantly decreased in depressed diabetic subjects compared to non-depressed diabetic subjects.

Analysis of index modulation of doppler microembolic signals part II: in vitro discrimination.

The purpose of this study was to validate through experiments that frequency modulation (FM) of microembolic signatures was principally due to the radiation force. Several experiments were required to prove that such a frequency modulation originates from microdisplacements induced by the radiation force acting on microbubbles. The first experiment was performed to verify that the diffraction effects due to the presence of a skull did not disturb the acoustic field appreciably and to validate that a radiation force in the brain was sufficient to create a detectable microdisplacement.

Simulation of shear wave propagation in a soft medium using a pseudospectral time domain method.

Elastography applications require the use of efficient models to simulate the propagation of shear waves in soft media such as human tissues. These models are needed to improve understanding of the measured displacement field, to reconstruct the viscoelasticity of heterogeneous tissues, and to test inversion algorithms. This paper reports a numerical model based on a pseudospectral time domain method developed to simulate shear and compression wave propagation in an axisymmetric heterogeneous viscoelastic medium.