Progress in Two-Dimensional Arrays for Real-Time Volumetric Imaging

1998 ◽  
Vol 20 (1) ◽  
pp. 1-15 ◽  
Author(s):  
E. D. Light ◽  
R. E. Davidsen ◽  
J.O. Fiering ◽  
T. A. Hruschka ◽  
S. W. Smith
Keyword(s):  
Real Time ◽  
Insertion Loss ◽  
Imaging System ◽  
Two Dimensional ◽  
Volumetric Imaging ◽  
Dimensional Array ◽  
Transducer Arrays ◽  
Volumetric Images ◽  
Duke University

The design, fabrication, and evaluation of two dimensional array transducers for real-time volumetric imaging are described. The transducers we have previously described operated at frequencies below 3 MHz and were unwieldy to the operator because of the interconnect schemes used in connecting to the transducer handle. Several new transducers have been developed using new connection technology. A 40 × 40 = 1,600 element, 3.5 MHz array was fabricated with 256 transmit and 256 receive elements. A 60 × 60 = 3,600 element 5.0 MHz array was constructed with 248 transmit and 256 receive elements. An 80 × 80 = 6,400 element, 2.5 MHz array was fabricated with 256 transmit and 208 receive elements. 2-D transducer arrays were also developed for volumetric scanning in an intracardiac catheter, a 10 × 10 = 100 element 5.0 MHz forward-looking array and an 11 × 13 = 143 element 5.0 MHz side-scanning array. The −6 dB fractional bandwidths for the different arrays varied from 50% to 63%, and the 50 Ω insertion loss for all the transducers was about −64 dB. The transducers were used to generate real-time volumetric images in phantoms and in vivo using the Duke University real time volumetric imaging system, which is capable of generating multiple planes at any desired angle and depth within the pyramidal volume.

scholarly journals Two-Dimensional Random Arrays for Real Time Volumetric Imaging

1994 ◽  
Vol 16 (3) ◽  
pp. 143-163 ◽  
Author(s):  
Richard E. Davidsen ◽  
Jørgen A. Jensen ◽  
Stephen W. Smith
Keyword(s):  
Uniform Distribution ◽  
Real Time ◽  
Imaging System ◽  
Frame Rate ◽  
Depth Of Field ◽  
System Response ◽  
Two Dimensional ◽  
Volumetric Imaging ◽  
Sparse Array ◽  
Random Array

Two-dimensional arrays are necessary for a variety of ultrasonic imaging techniques, including elevation focusing, 2-D phase aberration correction, and real time volumetric imaging. In order to reduce system cost and complexity, sparse 2-D arrays have been considered with element geometries selected ad hoc, by algorithm, or by random process. Two random sparse array geometries and a sparse array with a Mills cross receive pattern were simulated and compared to a fully sampled aperture with the same overall dimensions. The sparse arrays were designed to the constraints of the Duke University real time volumetric imaging system, which employs a wide transmit beam and receive mode parallel processing to increase image frame rate. Depth-of-field comparisons were made from simulated on-axis and off-axis beamplots at ranges from 30 to 160 mm for both coaxial and offset transmit and receive beams. A random array with Gaussian distribution of transmitters and uniform distribution of receivers was found to have better resolution and depth-of-field than both a Mills cross array and a random array with uniform distribution of both transmit and receive elements. The Gaussian random array was constructed and experimental system response measurements were made at several ranges. Comparisons of B-scan images of a tissue mimicking phantom show improvement in resolution and depth-of-field consistent with simulation results.

scholarly journals Performance of a novel protease-activated fluorescent imaging system for intraoperative detection of residual breast cancer during breast conserving surgery

2021 ◽  
Vol 187 (1) ◽  
pp. 145-153
Author(s):  
Conor R. Lanahan ◽  
Bridget N. Kelly ◽  
Michele A. Gadd ◽  
Michelle C. Specht ◽  
Carson L. Brown ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Real Time ◽  
Imaging System ◽  
Ex Vivo ◽  
Menopausal Status ◽  
Fluorescent Imaging ◽  
Cancer Subtypes ◽  
Surgical Workflow ◽  
Tumor Types

Abstract Purpose Safe breast cancer lumpectomies require microscopically clear margins. Real-time margin assessment options are limited, and 20–40% of lumpectomies have positive margins requiring re-excision. The LUM Imaging System previously showed excellent sensitivity and specificity for tumor detection during lumpectomy surgery. We explored its impact on surgical workflow and performance across patient and tumor types. Methods We performed IRB-approved, prospective, non-randomized studies in breast cancer lumpectomy procedures. The LUM Imaging System uses LUM015, a protease-activated fluorescent imaging agent that identifies residual tumor in the surgical cavity walls. Fluorescent cavity images were collected in real-time and analyzed using system software. Results Cavity and specimen images were obtained in 55 patients injected with LUM015 at 0.5 or 1.0 mg/kg and in 5 patients who did not receive LUM015. All tumor types were distinguished from normal tissue, with mean tumor:normal (T:N) signal ratios of 3.81–5.69. T:N ratios were 4.45 in non-dense and 4.00 in dense breasts (p = 0.59) and 3.52 in premenopausal and 4.59 in postmenopausal women (p = 0.19). Histopathology and tumor receptor testing were not affected by LUM015. Falsely positive readings were more likely when tumor was present < 2 mm from the adjacent specimen margin. LUM015 signal was stable in vivo at least 6.5 h post injection, and ex vivo at least 4 h post excision. Conclusions Intraoperative use of the LUM Imaging System detected all breast cancer subtypes with robust performance independent of menopausal status and breast density. There was no significant impact on histopathology or receptor evaluation.

scholarly journals Real-Time In Vivo Bioluminescent Imaging for Evaluating the Efficacy of Antibiotics in a Rat Staphylococcus aureus Endocarditis Model

2005 ◽  
Vol 49 (1) ◽  
pp. 380-387 ◽  
Author(s):  
Yan Q. Xiong ◽  
Julie Willard ◽  
Jagath L. Kadurugamuwa ◽  
Jun Yu ◽  
Kevin P. Francis ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Real Time ◽  
Imaging System ◽  
Bioluminescent Imaging ◽  
Vancomycin Therapy ◽  
Treatment Groups ◽  
Highly Sensitive ◽  
Relevant Animal Model ◽  
And Control

ABSTRACT Therapeutic options for invasive Staphylococcus aureus infections have become limited due to rising antimicrobial resistance, making relevant animal model testing of new candidate agents more crucial than ever. In the present studies, a rat model of aortic infective endocarditis (IE) caused by a bioluminescently engineered, biofilm-positive S. aureus strain was used to evaluate real-time antibiotic efficacy directly. This strain was vancomycin and cefazolin susceptible but gentamicin resistant. Bioluminescence was detected and quantified daily in antibiotic-treated and control animals with IE, using a highly sensitive in vivo imaging system (IVIS). Persistent and increasing cardiac bioluminescent signals (BLS) were observed in untreated animals. Three days of vancomycin therapy caused significant reductions in both cardiac BLS (>10-fold versus control) and S. aureus densities in cardiac vegetations (P < 0.005 versus control). However, 3 days after discontinuation of vancomycin therapy, a greater than threefold increase in cardiac BLS was observed, indicating relapsing IE (which was confirmed by quantitative culture). Cefazolin resulted in modest decreases in cardiac BLS and bacterial densities. These microbiologic and cardiac BLS differences during therapy correlated with a longer time-above-MIC for vancomycin (>12 h) than for cefazolin (∼4 h). Gentamicin caused neither a reduction in cardiac S. aureus densities nor a reduction in BLS. There were significant correlations between cardiac BLS and S. aureus densities in vegetations in all treatment groups. These data suggest that bioluminescent imaging provides a substantial advance in the real-time monitoring of the efficacy of therapy of invasive S. aureus infections in live animals.

Real-Time Intracardiac Two-Dimensional Echocardiography: An Experimental Study of In Vivo Feasibility, Imaging Planes, and Echocardiographic Anatomy

1990 ◽  
Vol 7 (4) ◽  
pp. 443-455 ◽  
Author(s):  
STEVEN L. SCHWARTZ ◽  
NATESA G. PANDIAN ◽  
BRENDA S. KUSAY ◽  
ROHIT KUMAR ◽  
ANDREW WEINTRAUB ◽  
...  
Keyword(s):  
Experimental Study ◽  
Real Time ◽  
Two Dimensional ◽  
Dimensional Echocardiography ◽  
Two Dimensional Echocardiography

scholarly journals Real-Time 3D Laparoscopic Ultrasonography

2005 ◽  
Vol 27 (3) ◽  
pp. 129-144 ◽  
Author(s):  
Edward D. Light ◽  
Salim F. Idriss ◽  
Kathryn F. Sullivan ◽  
Patrick D. Wolf ◽  
Stephen W. Smith
Keyword(s):  
Real Time ◽  
Insertion Loss ◽  
Pulmonary Veins ◽  
Intracardiac Echocardiography ◽  
Center Frequency ◽  
Ultrasound Transducers ◽  
Laparoscopic Ultrasonography ◽  
Chamber View ◽  
2D Array

We have previously described 2D array ultrasound transducers operating up to 10 MHz for applications including real time 3D transthoracic imaging, real time volumetric intracardiac echocardiography (ICE), real time 3D intravascular ultrasound (IVUS) imaging, and real time 3D transesophageal echocardiography (TEE). We have recently built a pair of 2D array transducers for real time 3D laparoscopic ultrasonography (3D LUS). These transducers are intended to be placed down a trocar during minimally invasive surgery. The first is a forward viewing 5 MHz, 11 times 19 array with 198 operating elements. It was built on an 8 layer multilayer flex circuit. The interelement spacing is 0.20 mm yielding an aperture that is 2.2 mm × 3.8 mm. The O.D. of the completed transducer is 10.2 mm and includes a 2 mm tool port. The average measured center frequency is 4.5 MHz, and the −6 dB bandwidth ranges from 15% to 30%. The 50 Ω insertion loss, including Gore MicroFlat cabling, is −81.2 dB. The second transducer is a 7 MHz, 36 times 36 array with 504 operating elements. It was built upon a 10 layer multilayer flex circuit. This transducer is in the forward viewing configuration and the interelement spacing is 0.18 mm. The total aperture size is 6.48 mm x 6.48 mm. The O.D. of the completed transducer is 11.4 mm. The average measured center frequency is 7.2 MHz, and the −6 dB bandwidth ranges from 18% to 33%. The 50 Ω insertion loss is −79.5 dB, including Gore MicroFlat cable. Real-time in vivo 3D images of canine hearts have been made including an apical 4-chamber view from a substernal access with the first transducer to monitor cardiac function. In addition, we produced real time 3D rendered images of the right pulmonary veins from a right parasternal access with the second transducer, which would be valuable in the guidance of cardiac ablation catheters for treatment of atrial fibrillation.

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