Quantitative photoacoustic measurement of tissue optical absorption spectrum aided by an optical contrast agent.

In photoacoustic imaging, the intensity of photoacoustic signal induced by optical absorption in biological tissue is proportional to light energy deposition, which is the product of the absorption coefficient and the local light fluence. Because tissue optical properties are highly dependent on the wavelength, the spectrum of the local light fluence at a target tissue beneath the sample surface is different than the spectrum of the incident light fluence. Therefore, quantifying the tissue optical absorption spectrum by using a photoacoustic technique is not feasible without the knowledge of the local light fluence.

Anniversary paper: evolution of ultrasound physics and the role of medical physicists and the AAPM and its journal in that evolution.

Ultrasound has been the greatest imaging modality worldwide for many years by equipment purchase value and by number of machines and examinations. It is becoming increasingly the front end imaging modality; serving often as an extension of the physician's fingers. We believe that at the other extreme, high-end systems will continue to compete with all other imaging modalities in imaging departments to be the method of choice for various applications, particularly where safety and cost are paramount.

Optical anisotropy in individual porous silicon nanoparticles containing multiple chromophores.

Polarization anisotropy is investigated in single porous silicon nanoparticles containing multiple chromophores. Two classes of nanoparticles, low current density and high current density, are studied. Low current density samples exhibit red-shifted spectra and contain only one or two chromophores.

Cardiac resynchronization therapy reduces the risk of hospitalizations in patients with advanced heart failure: results from the Comparison of Medical Therapy, Pacing and Defibrillation in Heart Failure (COMPANION) trial.

Background: In the Comparison of Medical Therapy, Pacing and Defibrillation in Heart Failure (COMPANION) trial, 1520 patients with advanced heart failure were assigned in a 1:2:2 ratio to optimal pharmacological therapy or optimal pharmacological therapy plus cardiac resynchronization therapy (CRT-P) or CRT with defibrillator (CRT-D). Use of CRT-P and CRT-D was associated with a significant reduction in combined risk of death or all-cause hospitalizations. Because mortality also was significantly reduced (optimal pharmacological therapy versus CRT-D only), an assessment of the true reduction in hospitalization rates must consider the competing risk of death and varying follow-up times.

Image registration for detection and quantification of change on digital tomosynthesis mammographic volumes.

Objective: The purpose of this study was to achieve 3D registration of digital tomosynthesis mammographic volumes using mutual information.

Conclusion: Registration of digital breast tomosynthesis mammographic volumes was achieved with an average error of 1.8 +/- 1.

The challenges of developing a trauma system for Indigenous people.

Trauma systems have been shown to provide the best trauma care for injured patients. A trauma system developed for Indigenous people should take into account many factors including geographical remoteness and cultural diversity. Indigenous people suffer from a significant intentional and non-intentional burden of injury, often greater than non-Indigenous populations, and a public health approach in dealing with trauma can be adopted.

Irbesartan in patients with heart failure and preserved ejection fraction.

Background: Approximately 50% of patients with heart failure have a left ventricular ejection fraction of at least 45%, but no therapies have been shown to improve the outcome of these patients. Therefore, we studied the effects of irbesartan in patients with this syndrome.

Methods: We enrolled 4128 patients who were at least 60 years of age and had New York Heart Association class II, III, or IV heart failure and an ejection fraction of at least 45% and randomly assigned them to receive 300 mg of irbesartan or placebo per day.

Suspicious breast lesions: assessment of 3D Doppler US indexes for classification in a test population and fourfold cross-validation scheme.

Purpose: To assess the diagnostic performance of various Doppler ultrasonographic (US) vascularity measures in conjunction with grayscale (GS) criteria in differentiating benign from malignant breast masses, by using histologic findings as the reference standard.

Materials And Methods: Institutional Review Board and HIPAA standards were followed. Seventy-eight women (average age, 49 years; range, 26-70 years) scheduled for breast biopsy were included.

A randomized controlled trial to evaluate the safety and efficacy of cardiac contractility modulation in patients with systolic heart failure: rationale, design, and baseline patient characteristics.

Cardiac contractility modulation (CCM) signals are nonexcitatory electrical signals delivered during the cardiac absolute refractory period that enhance the strength of cardiac muscular contraction. Prior research in experimental and human heart failure has shown that CCM signals normalize phosphorylation of key proteins and expression of genes coding for proteins involved in regulation of calcium cycling and contraction. The results of prior clinical studies of CCM have supported its safety and efficacy.

An optical NMR spectrometer for Larmor-beat detection and high-resolution POWER NMR.

Optical nuclear magnetic resonance (ONMR) is a powerful probe of electronic properties in III-V semiconductors. Larmor-beat detection (LBD) is a sensitivity optimized, time-domain NMR version of optical detection based on the Hanle effect. Combining LBD ONMR with the line-narrowing method of POWER (perturbations observed with enhanced resolution) NMR further enables atomically detailed views of local electronic features in III-Vs.

The risk of exposure to diagnostic ultrasound in postnatal subjects: nonthermal mechanisms.

This review examines the nonthermal physical mechanisms by which ultrasound can harm tissue in postnatal patients. First the physical nature of the more significant interactions between ultrasound and tissue is described, followed by an examination of the existing literature with particular emphasis on the pressure thresholds for potential adverse effects. The interaction of ultrasonic fields with tissue depends in a fundamental way on whether the tissue naturally contains undissolved gas under normal physiologic conditions.

Photoacoustic tomography of joints aided by an Etanercept-conjugated gold nanoparticle contrast agent-an ex vivo preliminary rat study.

Monitoring of anti-rheumatic drug delivery in experimental models and in human diseases would undoubtedly be very helpful for both basic research and clinical management of inflammatory diseases. In this study, we have investigated the potential of an emerging hybrid imaging technology-photoacoustic tomography-in noninvasive monitoring of anti-TNF drug delivery. After the contrast agent composed of gold nanorods conjugated with Etanercept molecules was produced, ELISA experiments were performed to prove the conjugation and to show that the conjugated anti-TNF-α drug was biologically active.

Heart failure with preserved ejection fraction: clinical characteristics of 4133 patients enrolled in the I-PRESERVE trial.

Background: We describe the baseline characteristics of subjects randomised in the largest placebo-controlled, morbidity-mortality trial to date in patients with heart failure and preserved ejection fraction - the irbesartan in heart failure with preserved systolic function trial (I-PRESERVE).

Methods And Results: 4133 patients with a mean age of 72 years (a third were 75 years or older) were randomised and 60% were women. The mean (SD) LVEF was 59 (9)% and almost 80% of patients were in NYHA Class III or IV.

Fibroblasts from non-healing human chronic wounds show decreased expression of beta ig-h3, a TGF-beta inducible protein.

Background: Increasing evidence shows persistent phenotypic alterations in fibroblasts from non-healing human chronic wounds, which may result in faulty extracellular matrix deposition and keratinocyte migration. We have previously shown that these cells are characterized by morphological changes, low proliferative potential and unresponsiveness to TGF-beta1, and down regulated phosphorylation of Smad 2/3 and p42/44 MAPK from decreased expression of the TGF-beta type II receptor.

Objective: To identify genes and proteins that may be differentially expressed in chronic wounds and their cultured fibroblasts.

Multi-modality 3D breast imaging with X-Ray tomosynthesis and automated ultrasound.

This study evaluated the utility of 3D automated ultrasound in conjunction with 3D digital X-Ray tomosynthesis for breast cancer detection and assessment, to better localize and characterize lesions in the breast. Tomosynthesis image volumes and automated ultrasound image volumes were acquired in the same geometry and in the same view for 27 patients. 3 MQSA certified radiologists independently reviewed the image volumes, visually correlating the images from the two modalities with in-house software.

Non-rigid registration of three-dimensional (3D) grayscale and Doppler ultrasound breast images.

The purpose of this study is to evaluate the accuracy of image volume based registration (IVBaR) of 3D ultrasound (US) image volumes of the whole breast acquired at different times. Successful IVBaR could aid in detection of tumor changes in response to neoadjuvant chemotherapy and potentially be useful for routine breast cancer screening and diagnosis. IVBaR was successful in 9 of 10 reproducibility studies, 11 of 15 image pairs collected before and after approximately 45 days of chemotherapy.

Influence of diabetes on cardiac resynchronization therapy with or without defibrillator in patients with advanced heart failure.

Objectives: We performed a post hoc analysis to determine the influence of cardiac resynchronization therapy with a defibrillator (CRT-D) or without a defibrillator (CRT-P) on outcomes among diabetic patients with advanced heart failure (HF).

Background: In patients with systolic HF, diabetes is an independent predictor of morbidity and mortality. No data are available on its impact on CRT-D or CRT-P in advanced HF.

Ultrasound of the fingers for human identification using biometrics.

It was hypothesized that the use of internal finger structure as imaged using commercially available ultrasound (US) scanners could act as a supplement to standard methods of biometric identification, as well as a means of assessing physiological and cardiovascular status. Anatomical structures in the finger including bone contour, tendon and features along the interphalangeal joint were investigated as potential biometric identifiers. Thirty-six pairs of three-dimensional (3D) gray-scale images of second to fourth finger (index, middle and ring) data taken from 20 individuals were spatially registered using MIAMI-Fuse software developed at our institution and also visually matched by four readers.

Low-dose oral enoximone enhances the ability to wean patients with ultra-advanced heart failure from intravenous inotropic support: results of the oral enoximone in intravenous inotrope-dependent subjects trial.

Background: We determined whether low-dose oral enoximone could wean patients with ultra-advanced heart failure (UA-HF) from intravenous (i.v.) inotropic support.

Towards aberration correction of transcranial ultrasound using acoustic droplet vaporization.

We report on the first experiments demonstrating the transcranial acoustic formation of stable gas bubbles that can be used for transcranial ultrasound aberration correction. It is demonstrated that the gas bubbles can be formed transcranially by phase-transitioning single, superheated, micron-size, liquid dodecafluoropentane droplets with ultrasound, a process known as acoustic droplet vaporization (ADV). ADV was performed at 550 kHz, where the skull is less attenuating and aberrating, allowing for higher-amplitudes to be reached at the focus.

Characterization of cysts using differential correlation coefficient values from two dimensional breast elastography: preliminary study.

Although simple cysts are easily identified using sonography, description and management of nonsimple cysts remains uncertain. This study evaluated whether the correlation coefficient differences between breast tissue and lesions, obtained from 2D breast elastography, could potentially distinguish nonsimple cysts from cancers and fibroadenomas. We hypothesized that correlation coefficients in cysts would be dramatically lower than surrounding tissue because noise, imaging artifacts, and particulate matter move randomly and decorrelate quickly under compression, compared with solid tissue.

Demographic and psychosocial predictors of acute perioperative pain for total knee arthroplasty.

Background: As the North American population ages, the prevalence of knee osteoarthritis and the surgical interventions (ie, total knee arthroplasty [TKA]) aimed at correcting pain and disability will also rise proportionally. Therefore, efforts to better understand the factors associated with surgical outcomes are warranted. To date, no studies have examined the impact of psychosocial factors on acute postoperative TKA pain.

Diagnosing cysts with correlation coefficient images from 2-dimensional freehand elastography.

Objective: We compared the diagnostic potential of using correlation coefficient images versus elastograms from 2-dimensional (2D) freehand elastography to characterize breast cysts.

Methods: In this preliminary study, which was approved by the Institutional Review Board and compliant with the Health Insurance Portability and Accountability Act, we imaged 4 consecutive human subjects (4 cysts, 1 biopsy-verified benign breast parenchyma) with freehand 2D elastography. Data were processed offline with conventional 2D phase-sensitive speckle-tracking algorithms.

Prediction of mode of death in heart failure: the Seattle Heart Failure Model.

Background: Prognosis and mode of death in heart failure patients are highly variable in that some patients die suddenly (often from ventricular arrhythmia) and others die of progressive failure of cardiac function (pump failure). Prediction of mode of death may facilitate decisions about specific medications or devices.

Methods And Results: We used the Seattle Heart Failure Model (SHFM), a validated prediction model for total mortality in heart failure, to assess the mode of death in 10,538 ambulatory patients with New York Heart Association class II to IV heart failure and predominantly systolic dysfunction enrolled in 6 randomized trials or registries.