scholarly journals Broadening the detection view of high-frequency linear-array-based photoacoustic computed tomography by using planar acoustic reflectors

2014 ◽  
Author(s):  
Guo Li ◽  
Jun Xia ◽  
Konstantin I. Maslov ◽  
Lihong V. Wang
Keyword(s):  
Computed Tomography ◽  
High Frequency ◽  
Linear Array

scholarly journals Accuracy of ultrasonography in detecting radiolucent soft-tissue foreign bodies

2014 ◽  
Vol 24 (02) ◽  
pp. 196-200
Author(s):  
Morteza Tahmasebi ◽  
Hamdollah Zareizadeh ◽  
Azim Motamedfar
Keyword(s):  
Foreign Body ◽  
Soft Tissue ◽  
High Frequency ◽  
Foreign Bodies ◽  
Linear Array ◽  
Foreign Body Removal ◽  
Retained Foreign Body ◽  
Array Transducer ◽  
Highly Sensitive ◽  
Objective Detection

Abstract Background and Objective: Detection of radiolucent soft-tissue foreign bodies is a challenging problem, which is especially further complicated when retained foreign body is highly suggested by clinicians but radiography is negative. So, blind exploration is sometimes hazardous for patients. The purpose of this study was to determine the accuracy of ultrasonography (USG) in detecting radiolucent soft-tissue foreign bodies in the extremities. Materials and Methods: From November 2011 to January 2012, patients with clinically suspected radiolucent soft-tissue foreign body and negative radiography were evaluated by USG with a 12-MHz linear array transducer. The patients with positive clinical and USG examination were included in our study and underwent exploration or USG removal. Results: Fifty-one patients underwent foreign body removal under ultrasonography-guided or surgical exploration and 47 patients had foreign body (31, 12, 3, and 1 case had thorn, wood, glass, and plastic, respectively). Ultrasound was positive in 50 patients. USG falsely predicted the presence of foreign body in four cases and was falsely negative in one of the cases. Accuracy, sensitivity, and positive predictive value were determined as 90.2%, 97.9%, and 92%, respectively. Conclusions: The real-time high-frequency USG is a highly sensitive and accurate tool for detecting and removing radiolucent foreign bodies which are difficult to be visualized by routine radiography.

Setting Mean Airway Pressure during High-frequency Oscillatory Ventilation According to the Static Pressure–Volume Curve in Surfactant-deficient Lung Injury

2003 ◽  
Vol 99 (6) ◽  
pp. 1313-1322 ◽  
Author(s):  
Thomas Luecke ◽  
Juergen P. Meinhardt ◽  
Peter Herrmann ◽  
Gerald Weisser ◽  
Paolo Pelosi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Lung Volume ◽  
High Frequency ◽  
Airway Pressure ◽  
Static Pressure ◽  
High Frequency Oscillatory Ventilation ◽  
Mean Airway Pressure ◽  
Oscillatory Ventilation ◽  
Hemodynamic Variables ◽  
High Frequency Oscillatory

Background Numerous studies suggest setting positive end-expiratory pressure during conventional ventilation according to the static pressure-volume (P-V) curve, whereas data on how to adjust mean airway pressure (P(aw)) during high-frequency oscillatory ventilation (HFOV) are still scarce. The aims of the current study were to (1) examine the respiratory and hemodynamic effects of setting P(aw) during HFOV according to the static P-V curve, (2) assess the effect of increasing and decreasing P(aw) on slice volumes and aeration patterns at the lung apex and base using computed tomography, and (3) study the suitability of the P-V curve to set P(aw) by comparing computed tomography findings during HFOV with those obtained during recording of the static P-V curve at comparable pressures. Methods Saline lung lavage was performed in seven adult pigs. P-V curves were obtained with computed tomography scanning at each volume step at the lung apex and base. The lower inflection point (Pflex) was determined, and HFOV was started with P(aw) set at Pflex. The pigs were provided five 1-h cycles of HFOV. P(aw), first set at Pflex, was increased to 1.5 times Pflex (termed 1.5 Pflex(inc)) and 2 Pflex and decreased thereafter to 1.5 times Pflex and Pflex (termed 1.5 Pflex(dec) and Pflex(dec)). Hourly measurements of respiratory and hemodynamic variables as well as computed tomography scans at the apex and base were made. Results High-frequency oscillatory ventilation at a P(aw) of 1.5 Pflex(inc) reestablished preinjury arterial oxygen tension values. Further increase in P(aw) did not change oxygenation, but it decreased oxygen delivery as a result of decreased cardiac output. No differences in respiratory or hemodynamic variables were observed when comparing HFOV at corresponding P(aw) during increasing and decreasing P(aw). Variation in total slice lung volume (TLVs) was far less than expected from the static P-V curve. Overdistended lung volume was constant and less than 3% of TLVs. TLVs values during HFOV at Pflex, 1.5 Pflex(inc), and 2 Pflex were significantly greater than TLVs values at corresponding tracheal pressures on the inflation limb of the static P-V curve and located near the deflation limb. In contrast, TLVs values during HFOV at decreasing P(aw) (i.e., 1.5 Pflex(dec) and Pflex(dec)) were not significantly greater than corresponding TLV on the deflation limb of the static P-V curves. The marked hysteresis observed during static P-V curve recordings was absent during HFOV. Conclusions High-frequency oscillatory ventilation using P(aw) set according to a static P-V curve results in effective lung recruitment, and slice lung volumes during HFOV are equal to those from the deflation limb of the static P-V curve at equivalent pressures.

Design and fabrication of high frequency BNT film based linear array transducer

2015 ◽  
Vol 41 ◽  
pp. S631-S637 ◽  
Author(s):  
Hongwei Liu ◽  
Wei Ren ◽  
Jinyan Zhao ◽  
Huifeng Zhao ◽  
Xiaoqing Wu ◽  
...  
Keyword(s):  
High Frequency ◽  
Linear Array ◽  
Array Transducer

Comparison of Linear Array Endoscopic Ultrasound and Helical Computed Tomography for the Staging of Periampullary Malignancies

2003 ◽  
Vol 10 (8) ◽  
pp. 890-897 ◽  
Author(s):  
David E. Rivadeneira ◽  
Mark Pochapin ◽  
Stephen R. Grobmyer ◽  
Michael D. Lieberman ◽  
Paul J. Christos ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Endoscopic Ultrasound ◽  
Linear Array ◽  
Helical Computed Tomography
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