OBJECTIVE To determine whether, compared with fundamental imaging, second harmonic imaging can improve the accuracy of dobutamine stress echocardiography for identifying viable myocardium, using nuclear imaging as a reference. PATIENTS 30 patients with chronic left ventricular dysfunction (mean (SD) age, 60 (8) years; 22 men). METHODS Dobutamine stress echocardiography was carried out in al...

Coded excitation methods offer the potential for improving the SNR without increasing the peak transmitted power and without sacrificing resolution. Our study examines the potential application of coded waveforms, specifically FM chirps, in harmonic imaging. Such a system, in which nonlinear echoes from tissue are used to form the image, requires the extraction and compression of the second har...

HARMONIC IMAGING USING A MECHANICAL SECTOR, B-MODE ULTRASOUND SYSTEM by Danna Gurari ADVISOR: Dr. William D. Richard August 2005 Saint Louis Missouri An ultrasound imaging system includes transmitting ultrasound waves into a human body, collecting the reflections, manipulating the reflections, and then displaying them on computer screen as a grayscale image. The standard approach for ultrasound...

Several ultrasound-based imaging modalities have been proposed for image guidance and monitoring of High-Intensity Focused Ultrasound (HIFU) surgery. However, accurate localization and characterization of the effective region of treatment (thermal lesion) remain the obstacles in the clinical implementation of HIFU ablation. Harmonic motion imaging for focused ultrasound (HMIFU) is a novel HIFU ...

Surgical procedures as a prelude to optical imaging are a rate-limiting step in experimental neuroscience. Towards automation of these procedures, we describe the use of nonlinear optical techniques to create a thinned skull window for transcranial imaging. Metrology by second harmonic generation was used to map the surfaces of the skull and define a cutting path. Plasma-mediated laser ablation...

A multimodal multiphoton nonlinear optical (NLO) microspectroscopy imaging system was developed using a femtosecond laser and a photonic crystal fiber. Coherent anti-Stokes Raman scattering (CARS) microspectroscopy was combined with two-photon excitation fluorescence and second-harmonic generation microscopy in one platform and the system was applied to diagnose liver fibrosis. Normal and liver...

Second-harmonic generation (SHG) imaging is combined with coherent anti-Stokes Raman scattering (CARS) microscopy to follow the process of optical clearing in human skin ex vivo using dimethyl sulfoxide (DMSO) as the optical clearing agent. SHG imaging revealed that DMSO introduces morphological changes to the collagen I matrix. By carefully measuring the dynamic tissue attenuation of the coher...

Background Contrast-enhanced ultrasonography by means of Levovist, a galactose-based ultrasound contrast agent that is infused intravenously has allowed the observation of the vasculature of the abdominal organs. Particularly, contrast harmonic imaging, which is the specific imaging mode for Levovist, can depict signals from microbubbles in very slow flow without Doppler-related artifacts and i...

BACKGROUND Second harmonic imaging is a new ultrasound technique that allows evaluation of brain tissue perfusion after application of an ultrasound contrast agent. OBJECTIVE To evaluate the potential of this technique for the assessment of abnormal echo contrast characteristics of different brain tumours. METHODS 27 patients with brain tumours were studied. These were divided into four gro...