Transcranial Focused Ultrasound (tFUS) is a promising new potential neuromodulation tool. However, the safety of tFUS neuromodulation has not yet been assessed adequately. Patients with refractory temporal lobe epilepsy electing to undergo an anterior temporal lobe resection present a unique opportunity to evaluate the safety and efficacy of tFUS neuromodulation. Histological changes in tissue after tFUS can be examined after surgical resection, while further potential safety concerns can be assessed using neuropsychological testing. Neuropsychological functions were assessed in eight patients before and after focused ultrasound sonication of the temporal lobe at intensities up to 5760 mW/cm2. Using the BrainSonix Pulsar 1002, tFUS was delivered under MR guidance, using the Siemens Magnetom 3T Prisma scanner. Neuropsychological changes were assessed using various batteries. Histological changes were assessed using hematoxylin and eosin staining, among others. With respect to safety, the histological analysis did not reveal any detectable damage to the tissue, except for one subject for whom the histology findings were inconclusive. In addition, neuropsychological testing did not show any statistically significant changes in any test, except for a slight decrease in performance on one of the tests after tFUS. This study supports the hypothesis that low-intensity Transcranial Focused Ultrasound (tFUS) used for neuromodulation of brain circuits at intensities up to 5760 mW/cm2 may be safe for use in human research. However, due to methodological limitations in this study and inconclusive findings, more work is warranted to establish the safety. Future directions include greater number of sonications as well as longer exposure at higher intensity levels to further assess the safety of tFUS for modulation of neuronal circuits.

Although clinical evidence of successful autologous fat transfer (AFT) using third-generation ultrasound-assisted liposuction (UAL) is readily available, no study has quantified adipocyte viability using standardized methods. The authors assess acute adipocyte viability following fat aspiration as a first step in determining the overall efficacy of using third-generation UAL for AFT. Lipoaspirate samples were collected from patients who underwent elective liposuction procedures at multiple surgery centers. Patients with a history of bleeding disorders, diabetes, human immunodeficiency virus, or lipoatrophy disorders were excluded. The UAL system (VASER; Sound Surgical Technologies, Inc, Louisville, Colorado) was set at 60% amplitude in pulsed mode with vacuum aspiration of 15 in Hg or less. Laboratory analysis included free lipid volume, viability via lipolysis and propidium iodide staining, and cytological analysis, including cell surface protein examination and hematoxylin and eosin staining. The lipolysis assay revealed metabolically active adipocytes with a mean (SD) correlative viability of 85.1% (11%). Direct measures of acute viability via propidium iodide staining resulted in a mean (SD) viability measure of 88.7% (3.5%). Both mean values are within the historical range reported from syringe and vacuum-assisted lipoaspiration. Aqueous and lipid contents were favorably reduced after washing and filtering (Puregraft system; Cytori Therapeutics, Inc, San Diego, California). Cellular phenotypes identified were primarily white blood cells or vascular endothelial and vascular associated cells. Adipose tissue acquired via third-generation UAL is viable at harvest and is potentially a suitable source for autologous fat grafts. These results confirm reported clinical successes utilizing third-generation ultrasound lipoaspirate for AFT.

This article presents basic principles of hydrophone measurements, including mechanisms of action for various hydrophone designs, sensitivity and directivity calibration procedures, practical considerations for performing measurements, signal processing methods to correct for both frequency-dependent sensitivity and spatial averaging across the hydrophone sensitive element, uncertainty in hydrophone measurements, special considerations for high-intensity therapeutic ultrasound, and advice for choosing an appropriate hydrophone for a particular measurement task. Recommendations are made for information to be included in hydrophone measurement reporting.

Non-invasive LIFUP (Low Intensity Focused Ultrasound Pulsation) neuromodulation provides a unique approach to both investigating and treating the brain. This work describes a well-calibrated, simple-to-use ultrasound stimulation system for neuromodulation studies. It provides a single element 650 kHz transducer design and a straightforward control mechanism, with extensive calibration and internal electronic monitoring to prevent unwanted over or under treatment. One goal of this approach is to relieve researchers of many of the details associated with developing their own exposure equipment. A unique transducer positioning system and distinctive MRI fiducial targets simplify alignment and targeting. The system design, control software, calibration and alignment techniques are described in detail. Examples of transducer targeting and neurostimulation using the system are provided.

A quick review of the specification sheets for new technologically intensive diagnostic ultrasound systems reveals a substantial number of fairly impressive operational performance claims. In at least one manufacturer's published material, the system specifications boasts of a dynamic range of 180 dB. To put that number in perspective, a device capable of 180 dB of dynamic range of resolution would be able to detect the flutter of a butterfly's wing in the middle of a thermonuclear explosion. How does one verify such an astounding performance claim using currently available ultrasound testing devices such as a tissue-mimicking phantom and what is the explicit clinical significance of such dynamic range? Additionally, while most of us were focused with amazement in leapfrog advances in system technology, diagnostic ultrasound transducers were also undergoing radical changes in array material composition and design. Most modern composite transducer specifications claim fractional bandwidths of 85%, and more and element counts as high as 2500. While the great technological strides made in ultrasound system design have been impressive, all of the computational and processing power of the 'all-digital' ultrasound device is singularly dependent on the output and input characteristics of the ultrasound transducer. Published data shows that the ultrasound transducer is subject to degradation in performance, as well as element failure, potentially leading to patient misdiagnosis or under-diagnosis. The need to regularly test transducers for performance variances will be explored within this paper. Additionally, the key areas of transducer performance as they relate to image and Doppler quality will be defined.