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Barry B Goldberg

Publications and source records attributed to Barry B Goldberg.

At least 19 recordsLinked to original sources
PubMed2006

The influence of acoustic transmit parameters on the destruction of contrast microbubbles in vitro.

In this study, the destruction of the contrast agent Sonazoid (GE Healthcare, Oslo, Norway) was measured in vitro as a function of centre frequency (2-3 MHz), acoustic amplitude (0.66-1.6 MPa), pulse length (2-16 cycles) and PRF (0.5-8.0 kHz). Up to 82% of microbubbles were destroyed after exposure to a single 1.6 MPa acoustic pulse (16 cycles, 2.5 MHz and PRF of 1.0 kHz), while at a low amplitude of 0.66 MPa, fractional destruction increased gradually from 0 to 40% after exposure to 9 (identical) pulses. Fractional destruction increased from approximately 8 to 66% as pulse length was changed from 2 to 16 cycles following exposure to a single 2.5 MHz, 1.3 MPa pulse. As the PRF was increased from 0.5 to 8.0 kHz, shorter exposure time intervals (from 4.8 to 1.2 ms) were needed to achieve the same fractional destruction of 80%. Conversely, as the transmit frequency was increased from 2 to 3 MHz the fractional destruction decreased (by more than half within the first 3 pulses). The influence of changes in acoustic pressure and duty cycle on the destruction of Sonazoid microbubbles was highly statistically significant (p < or = 0.01) with a threshold around 0.67 MPa for a duty cycle of 0.0064. In conclusion, the fractional destruction increases with the duty cycle and the acoustic pressure amplitude and decreases with ultrasonic transmit frequency. Better understanding of the influence of the ultrasound transmit parameters on the destruction of contrast microbubbles should help improve existing contrast-assisted imaging modalities and may help develop new techniques for better use of contrast agents.

Contrast Media↗
PubMed2006

Contrast enhanced ultrasound for radio frequency ablation of canine prostates: initial results.

PURPOSE: We determined the feasibility of contrast enhanced ultrasound for radio frequency ablation of the entire prostate as a method of minimally invasive treatment for prostate cancer in a canine model. MATERIALS AND METHODS: Approval of the Institutional Animal Use and Care committee was obtained. Initially 5 dogs (group 1) were tested using variable power (5 to 30 W), time (4 to 12 minutes), bolus (0.01 to 0.04 ml/kg) and infusion (3 to 11 ml per minute at 0.015 microl/kg) injections of an ultrasound contrast agent with conventional grayscale power Doppler and pulse inversion harmonic imaging to establish optimal parameters. Subsequently 4 dogs (group 2) underwent entire prostate ablation using parameters based on group 1. The size of the thermal lesions and residual viable tissue was measured with ImageJ software (National Institutes of Health, Bethesda, Maryland) on ultrasound and pathological study. Linear regression and Student's t test were used for statistical analysis. RESULTS: A bolus of 0.04 ml/kg, an infusion of 11 ml per minute at 0.015 microl/kg and the contrast enhanced pulse inversion harmonic imaging mode were ranked best for guiding ablation. Thermal lesion volume was proportional to ablation power and time. There was no significant difference in measured thermal lesion size in group 1 between ultrasound and pathological findings (mean +/- SD 1.51 +/- 0.74 and 1.46 +/- 0.74 cm3, p = 0.56) or in residual viable tissue in group 2 (0.43 +/- 0.043 and 0.41 +/- 0.291 cm3, p = 0.21). The average volume of prostate ablation achieved in group 2 was 96.3%. CONCLUSIONS: Contrast enhanced pulse inversion harmonic imaging is able to guide, monitor and control radio frequency ablation of the entire prostate.

Animals↗
PubMed2005

In vivo pressure estimation using subharmonic contrast microbubble signals: proof of concept.

Changes in ambient pressure affects the reflectivity of ultrasound contrast microbubbles leading to an excellent correlation between subharmonic signals and hydrostatic pressure. The aortas of two dogs were scanned with an experimental pulse-echo system to validate in vivo pressure estimation based on subharmonic microbubble signals. Results matched well with instantaneous pressure measurements (from 20-60 mmHg) obtained simultaneously with a pressure catheter (root mean square errors <27%).

Algorithms↗
PubMed2005

On the usefulness of the mechanical index displayed on clinical ultrasound scanners for predicting contrast microbubble destruction.

OBJECTIVE: The purpose of this study was to evaluate the mechanical index (MI) displayed on clinical ultrasound scanners as a predictor of exposure conditions related to the destruction of sonographic microbubble contrast agents. METHODS: Sonazoid (GE Healthcare, Oslo, Norway) and Optison (GE Healthcare, Princeton, NJ) microbubbles were injected into a tissue-mimicking flow phantom. Gray scale imaging was performed with 4 different scanners and 3 different transducers (3.5 MHz curved linear, 2.5 MHz convex, and 7.5 MHz linear array), and the MI displayed by the scanner was varied from 0.2 to 1.5 by changing the system output power. All other scanning parameters were kept constant. Downstream changes in echogenicity were monitored with a PowerVision 7000 scanner (Toshiba America Medical Systems, Tustin, CA) as an indirect measure of bubble destruction. Video intensity changes within the flow tube were determined as a function of MI for the different scanner/transducer combinations, and the best linear fit was determined. RESULTS: At a displayed MI of 0.7, different scanner/transducer combinations exhibited a range in video intensity from +16% to -3% of baseline for Sonazoid and from +8% to -71% for Optison. At an MI of 0.3, reductions in video intensity of up to 32% were produced. These results indicate a wide range in bubble destruction at identical MI values. Likewise, regression analysis found no linear fits for all scanner/transducer combinations (r2 < 0.046). CONCLUSIONS: The MI displayed on clinical ultrasound scanners does not predict the degree of microbubble destruction and should not be used by itself to define exposure conditions for destruction of microbubble contrast agents.

Acoustics↗
PubMed2005

Contrast-enhanced sonographic imaging of lymphatic channels and sentinel lymph nodes.

OBJECTIVE: The purpose of this study was to determine whether lymphatic channels (LCs) and sentinel lymph nodes (SLNs) could be detected on sonographic imaging after subcutaneous, submucosal, or parenchymal injections of a sonographic contrast agent (ie, lymphosonography) in a variety of anatomic locations in several animal models. METHODS: Eight swine, 7 canines, 4 rabbits, and a monkey were used for these evaluations. Gray scale pulse inversion harmonic imaging of the LCs and the SLNs was performed after subcutaneous (n = 58), submucosal (n = 14), or parenchymal (n = 8) injections of a tissue-specific sonographic contrast agent (Sonazoid; GE Healthcare, Oslo, Norway). In many instances, blue dye was injected into the same locations as Sonazoid, and surgical dissection of the SLNs and LCs was performed for comparison. Scanning electron microscopy (SEM) of contrast-enhanced and control lymph nodes from 2 rabbits was performed to determine the mechanism of contrast agent uptake and retention within SLNs. RESULTS: After subcutaneous, submucosal, or parenchymal contrast agent injections, gray scale pulse inversion harmonic imaging could be used to identify the number and location(s) of LCs and SLNs. After subcutaneous, submucosal, or parenchymal contrast agent injections, Sonazoid was confined to the SLNs (ie, contrast enhancement was not detected in the second-echelon nodes). There was good agreement between the results of lymphosonography and blue dye with surgical dissection in identifying the regional LCs and SLNs. Scanning electron microscopy identified vacuoles representing intact contrast microbubbles within contrast-enhanced SLN macrophages, which were not present in the control lymph nodes. CONCLUSIONS: Lymphosonography can be used to detect lymphatic drainage pathways and SLNs in a variety of animal models.

Abdomen↗
PubMed2004

Image enhancement by acoustic conditioning of ultrasound contrast agents.

A novel contrast imaging technique has been developed for use with microbubble contrast agents. It employs two acoustic fields: there is an excitation field for conditioning microbubbles and an imaging field for detecting microbubbles. The maximum increases (due to microbubble conditioning) in scattered first and second harmonic signals were 14.5 and 16 dB, respectively. This technique is unique for effectively enhancing the blood-to-tissue image contrast.

Albumins↗
PubMed2004

Effect of shell type on the in vivo backscatter from polymer-encapsulated microbubbles.

This study compared in vivo enhancement from four different polymer-encapsulated ultrasound (US) contrast agents. The agents were produced with a rigid shell composed of the biodegradable block copolymer poly[D,L-lactide-co-glycolide] (PLGA) with the lactic and glycolic acid ratios 50:50, 75:25, 85:15 and 100:0 (i.e., increasingly hydrophobic shell compositions). Approximately the same bubble diameter (1.2 microm) and concentration (0.4 g/mL) were obtained for each agent. In four rabbits, audio Doppler signals were acquired from a 10 MHz cuff transducer placed around a surgically exposed vessel (contrast dose: 0.0125 to 0.15 mL/kg). In vivo dose responses were calculated off-line (in dB). Nine rabbit kidneys were imaged during contrast administration (0.1 mL/kg) in power Doppler and grey-scale pulse inversion harmonic (PIHI) modes using an HDI 5000 scanner (Philips Medical Systems, Bothell, WA). Time-intensity curves were produced and the time-to-peak, peak intensity, slope, area under the curve (AUC) and total duration of enhancement for each agent were compared. All agents produced marked Doppler enhancement with increasing duration from the 50:50 agent (48 +/- 10 s) to the 75:25 agent (166 +/- 46 s), the 85:15 agent (403 +/- 83 s) and with the 100:0 agent (603 +/- 93 s) lasting longest (p < 0.02). No other parameters changed significantly, except the AUC of the 85:15 agent, which was greater than that of the 50:50 agent (190.75 vs. 61.58; p = 0.02). The in vivo dose-response curves were similar for all agents, with mean enhancement up to 20.6 +/- 1.11 dB (p = 0.17). In conclusion, contrast duration increases by an order of magnitude as the lactic acid component in the polymer-encapsulated bubbles increases and the shell, thus, becomes increasingly hydrophobic.

Animals↗
PubMed2004

Sentinel lymph nodes in a swine model with melanoma: contrast-enhanced lymphatic US.

PURPOSE: To determine if lymphatic channels and sentinel lymph nodes (SLNs) with and without metastases can be detected with lymphatic ultrasonography (US) after peritumoral injection of a US contrast agent and to determine if lymphatic US can be used to assess SLNs for the presence of metastatic infiltration. MATERIALS AND METHODS: Six swine with 17 melanomas were evaluated. Conventional gray-scale, color flow, and gray-scale phase-inversion harmonic US examinations were performed. A US contrast agent was administered in four sites around each melanoma (1-mL total dose). Lymphoscintigraphy was followed by injection of a blue dye and then dissection. SLNs identified at lymphatic US were characterized by two readers in consensus as normal or as having metastases; results were compared with histologic findings. Statistical analyses included the sign test and the kappa statistic. RESULTS: Lymphatic US depicted 28 SLNs, while lymphoscintigraphy depicted 27 "hot spots" suspected of representing SLNs (including two false-positive findings). Dissection after blue dye injection helped identify 31 SLNs. There were no false-positive US findings for SLN detection. Five of six nodes not seen with lymphoscintigraphy were detected with lymphatic US. The accuracy of SLN detection was 90% (28 of 31) for lymphatic US and 81% (25 of 31) for lymphoscintigraphy (P =.29). Lymphatic US correctly depicted metastases in 19 of 20 SLNs, and five of the eight normal SLNs were correctly characterized, with an accuracy of 86% (kappa = 0.62). CONCLUSION: Detection of SLNs with lymphatic US compared favorably with that at lymphoscintigraphy. Lymphatic US can depict metastases within the SLN, which was not possible with lymphoscintigraphy.

Animals↗
PubMed2004

Catheter-based intraluminal sonography.

With the development of interventional and minimally invasive surgical techniques in the last decade, a strong interest in intraluminal sonography has arisen because of the need for better imaging information and management of the interventional procedure. High-resolution intraluminal sonography is a unique approach for the evaluation of a wide range of abnormalities within the luminal structures throughout the body. This imaging technique has been able to obtain information not available with even the most sophisticated percutaneous sonography, CT, or MRI. The uniqueness of this approach has led to extensive research, establishing a variety of clinical applications. These miniature catheter-based transducers have become important supplemental tools in the evaluation of the urinary and gastrointestinal tracts. Other areas need to be evaluated more thoroughly before efficacy is established, but the concept of using miniature transducers has shown promise in many areas of the body. This should lead to the provision of important information for decision making relative to patient care and surgical intervention. In the future, with projected technical progress, intraluminal sonography should substantially improve its diagnostic capabilities.

Catheterization↗
PubMed2004

Diagnosing breast lesions with contrast-enhanced 3-dimensional power Doppler imaging.

OBJECTIVE: To compare mammography with contrast-enhanced 2- and 3-dimensional power Doppler imaging for the diagnosis of breast cancer. METHODS: Fifty-five patients, who underwent breast biopsies with histopathologic assessment, participated in a study of mammography and contrast-enhanced sonography. Levovist (Berlex Laboratories, Montville, NJ) and Optison (Mallinckrodt, St Louis, MO) were administrated to 22 and 33 patients, respectively. Precontrast and postcontrast 2-dimensional power Doppler data of the lesion were obtained with an HDI 3000 system (Philips Medical Systems, Bothell, WA), and 3-dimensional data were acquired with an LIS 6000A system (Life Imaging Systems Inc, London, Ontario, Canada). Two independent and blinded readers assessed diagnosis. Receiver operating characteristic curves were computed individually and in combination for mammography and 2- and 3-dimensional sonography (before and after contrast). Histopathologic and imaging parameters were compared by Mann-Whitney statistics. RESULTS: Mammographic findings were available for 50 patients, biopsy for 54, and 2- and 3-dimensional sonographic images for 53 and 52, respectively. Of the 50 patients who had all 4 measures, 15 (30%) had malignancies. The areas under the receiver operating characteristic curve for the diagnosis of breast cancer were 0.51 for 2-dimensional contrast-enhanced imaging, 0.60 for 3-dimensional power Doppler imaging, and 0.76 for 3-dimensional contrast-enhanced imaging (P < .01). Mammography produced an area of 0.86, which increased when combined with 3-dimensional contrast-enhanced imaging to 0.90 and with all sonographic modalities to 0.96 (P < .001). The histopathologic diagnosis of benign or malignant correlated with the presence or absence of anastomoses and with the degree of vascularity assessed with contrast-enhanced 3-dimensional power Doppler imaging (P = .007 and .02). CONCLUSIONS: Contrast-enhanced 3-dimensional power Doppler imaging increases the ability to diagnose breast cancer relative to conventional 2- and 3-dimensional sonographic imaging.

Adult↗
PubMed2003

Classification of breast masses in ultrasonic B scans using Nakagami and K distributions.

Classification of breast masses in greyscale ultrasound images is undertaken using a multiparameter approach. Five parameters reflecting the non-Rayleigh nature of the backscattered echo were used. These parameters, based mostly on the Nakagami and K distributions, were extracted from the envelope of the echoes at the site, boundary, spiculated region and shadow of the mass. They were combined to create a linear discriminant. The performance of this discriminant for the classification of breast masses was studied using a data set consisting of 70 benign and 29 malignant cases. The Az value for the discriminant was 0.96 +/- 0.02, showing great promise in the classification of masses into benign and malignant ones. The discriminant was combined with the level of suspicion values of the radiologist leading to an Az value of 0.97 +/- 0.014. The parameters used here can be calculated with minimal clinical intervention, so the method proposed here may therefore be easily implemented in an automated fashion. These results also support the recent reports suggesting that ultrasound may help as an adjunct to mammography in breast cancer diagnostics to enhance the classification of breast masses.

Adult↗
PubMed2003

ROC analysis of ultrasound tissue characterization classifiers for breast cancer diagnosis.

Breast cancer diagnosis through ultrasound tissue characterization was studied using receiver operating characteristic (ROC) analysis of combinations of acoustic features, patient age, and radiological findings. A feature fusion method was devised that operates even if only partial diagnostic data are available. The ROC methodology uses ordinal dominance theory and bootstrap resampling to evaluate A(z) and confidence intervals in simple as well as paired data analyses. The combined diagnostic feature had an A(z) of 0.96 with a confidence interval of at a significance level of 0.05. The combined features show statistically significant improvement over prebiopsy radiological findings. These results indicate that ultrasound tissue characterization, in combination with patient record and clinical findings, may greatly reduce the need to perform biopsies of benign breast lesions.

Age Factors↗
PubMed2003

Computer-aided classification of breast masses in ultrasonic B-scans using a multiparameter approach.

Classification of breast masses in ultrasonic B-scan images is undertaken using a multiparameter approach. The parameters are generated on the basis of a non-Rayleigh statistic model of the backscattered envelope from the breast tissue. They can be computed automatically with minimal clinical intervention once the location of the mass is known. A new discriminant is developed that combines these parameters linearly. It is seen that this new discriminant performs classification of masses into benign or malignant better than the classification by any one of the individual parameters. The data set studied consisted of 99 cases (70 patients with benign masses and 29 patients with malignant masses). The areas under the receiver operating characteristic (ROC) curves (Az) and statistical attributes of the areas were studied to establish the enhancement in performance. The Az value after combining all the parameters was found to be 0.8701. Upon combining this parameter with the level of suspicion (LOS) scores of a radiologist, the performance is further enhanced with an area under the (empirical) ROC of 0.94 having an operating point at a sensitivity of 0.965 and specificity of 0.87. It is suggested that this automated approach may hold promise as a means of classifying breast masses.

Algorithms↗
PubMed2003

Power Doppler assessment of vascular changes during fracture treatment with low-intensity ultrasound.

OBJECTIVE: To study the use of power Doppler sonography for assessing changes in vascularity during treatment of fracture sites with low-intensity ultrasound. METHODS: In 6 dogs (3 pairs), subcutaneous dissection of the midshaft of the ulna allowed symmetrical osteotomies to be made with a reciprocation saw. Three dogs were treated and 3 were used as controls. The fracture site was subjected to 1.5-MHz low-intensity ultrasound (30 mW/cm2) for 20 minutes daily from a therapeutic ultrasonic device. Gray scale sonography was performed to evaluate the fracture site. Power Doppler sonography was used to assess flow patterns at the fracture site and surrounding soft tissue. A sonographic contrast agent was administered intravenously. The dose was 0.2 mL/kg. RESULTS: Power Doppler sonography showed an increase in flow around the fracture site in the treated dogs compared with that in control dogs. Color pixel values on day 7 were 3-fold higher in treated legs than control legs and on day 11 were 33% higher in treated legs than control legs. Enhancement after contrast agent administration was consistently higher in treated legs than control legs. CONCLUSIONS: Power Doppler sonography showed increased vascularity around the fracture sites in treated dogs with and without contrast agent administration.

Animals↗