Cumulative incidence of post‐infection asthma or wheezing among young children clinically diagnosed with respiratory syncytial virus infection in the United States: A retrospective database analysis

Background: Respiratory syncytial virus (RSV) infection is implicated in subsequent development of asthma/wheezing (AW) among term and pre-term infants. We describe the cumulative incidence of AW among hospitalized and ambulatory neonates/infants/toddlers following RSV infection diagnosis over three independent follow-up periods. Methods: Between January 1, 2007 and March 31, 2016, patients aged 0-2 years old with first clinical diagnosis of RSV infection were identified using the Optum® integrated electronic health records and claims database. Patients diagnosed with AW ≤30 days post-RSV diagnosis were excluded. Three cohorts with 1, 3 and 5 years of follow-up were stratified by presence or absence of specific RSV high-risk factors, including pre-term birth and pre-defined, pre-existing comorbidities. Descriptive statistics and logistic regression results were reported.Results: Overall, 9811, 4524 and 1788 RSV-infected high-risk-factor negative patients were included in 1, 3 and 5-year independent cohorts, respectively. Of these, 6.5%, 6.9% and 5.8%, respectively had RSV-related hospitalization. By the end of follow-up, 14.9%, 28.2% and 36.3% had AW events. Overall, 3030, 1378 and 552 RSV-infected high-risk-factor positive patients were included in the respective cohorts. Of these, 11.4%, 11.1% and 11.6%, respectively were hospitalized with initial RSV infection and 18.1%, 32.9% and 37.9% had subsequent AW events within the follow-up period. Logistic regression confirmed RSV-related hospitalization significantly increased the likelihood of developing AW (

A remote temperature sensor for an ultrasound hyperthermia system using the acoustic signal derived from the heating signals

We demonstrate a non-invasive technique, based on the modal frequency shift of a region insonified by a dual-beam ultrasound (US) transducer (region of interest, ROI), to remotely assess the temperature of the region in a tissue-mimicking object. The application is in ultrasound hyperthermia systems for controlled maintenance of tumour temperature during chemotherapy. Towards this, we have characterised the variation of the storage modulus with the temperature of two tissue-mimicking visco-elastic materials. Due to this variation in tissue storage modulus (and viscosity), we have observed a shift in the resonant modes of the ROI, vibrated remotely with a dual-beam focussed ultrasound transducer. A modal analysis of the vibrating ROI is done to identify the modes captured by the detector. A variation in this modal frequency with temperature is computed and matches reasonably well with the experimental measurements. Through this, we demonstrate that an ultrasound hyperthermia system can have a remote temperature sensor without using an additional imaging modality

Orthotropic elastic moduli of biological tissues from ultrasound-assisted diffusing-wave spectroscopy

We obtain vibro-acoustic (VA) spectral signatures of a remotely palpated region in tissue or tissue-like objects through diffusing-wave spectroscopy (DWS) measurements. Remote application of force is through focused ultrasound, and the spectral signatures correspond to vibrational modes of the focal volume (also called the ROI) excited through ultrasound forcing. In DWS, one recovers the time evolution of mean-square displacement (MSD) of Brownian particles from the measured decay of intensity autocorrelation of light, adapted also to local particles pertaining only to the ROI. We observe that the plateau of the MSD-versus-time curve has noisy fluctuations when ultrasound is applied, which disappear when forcing is removed. It is shown that the spectrum of fluctuations contains peaks corresponding to some of the modes of vibration of the ROI. This enables us to measure the vibrational modes carried by VA waves. We also show recovery of components of the orthotropic elastic tensor pertaining to the material of the ROI from the measured vibrational modes. We first recover the elastic constants for agar slabs, which are verified to be isotropic. Thereafter, we repeat the exercise on fat recovered from pork back tissue, which, from these measurements, is seen to be orthotropic. We validate some of our present measurements through independent runs in a rheometer. The present work is the first step taken, to the best of our knowledge, to characterize biological tissue on the basis of the anisotropic elasticity property, which may potentially aid in the diagnosis and tracking of the progress of cancer in soft-tissue organs. (C) 2017 Optical Society of Americ

Quantitative vibro-acoustography of tissue-like objects by measurement of resonant modes

We demonstrate a simple and computationally efficient method to recover the shear modulus pertaining to the focal volume of an ultrasound transducer from the measured vibro-acoustic spectral peaks. A model that explains the transport of local deformation information with the acoustic wave acting as a carrier is put forth. It is also shown that the peaks correspond to the natural frequencies of vibration of the focal volume, which may be readily computed by solving an eigenvalue problem associated with the vibrating region. Having measured the first natural frequency with a fibre Bragg grating sensor, and armed with an expedient means of computing the same, we demonstrate a simple procedure, based on the method of bisection, to recover the average shear modulus of the object in the ultrasound focal volume. We demonstrate this recovery for four homogeneous agarose slabs of different stiffness and verify the accuracy of the recovery using independent rheometer-based measurements. Extension of the method to anisotropic samples through the measurement of a more complete set of resonant modes and the recovery of an elasticity tensor distribution, as is done in resonant ultrasound spectroscopy, is suggested