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Active ultrasound pattern injection system (AUSPIS) for interventional tool guidance.

Guo X, Kang HJ, Etienne-Cummings R, Boctor EM - PLoS ONE (2014)

Bottom Line: Accurate tool tracking is a crucial task that directly affects the safety and effectiveness of many interventional medical procedures.Compared to CT and MRI, ultrasound-based tool tracking has many advantages, including low cost, safety, mobility and ease of use.We performed ex vitro and in vivo experiments, showing significant improvements of tool visualization and accurate localization using different US imaging platforms.

View Article: PubMed Central - PubMed

Affiliation: Dept. of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, United States of America.

ABSTRACT
Accurate tool tracking is a crucial task that directly affects the safety and effectiveness of many interventional medical procedures. Compared to CT and MRI, ultrasound-based tool tracking has many advantages, including low cost, safety, mobility and ease of use. However, surgical tools are poorly visualized in conventional ultrasound images, thus preventing effective tool tracking and guidance. Existing tracking methods have not yet provided a solution that effectively solves the tool visualization and mid-plane localization accuracy problem and fully meets the clinical requirements. In this paper, we present an active ultrasound tracking and guiding system for interventional tools. The main principle of this system is to establish a bi-directional ultrasound communication between the interventional tool and US imaging machine within the tissue. This method enables the interventional tool to generate an active ultrasound field over the original imaging ultrasound signals. By controlling the timing and amplitude of the active ultrasound field, a virtual pattern can be directly injected into the US machine B mode display. In this work, we introduce the time and frequency modulation, mid-plane detection, and arbitrary pattern injection methods. The implementation of these methods further improves the target visualization and guiding accuracy, and expands the system application beyond simple tool tracking. We performed ex vitro and in vivo experiments, showing significant improvements of tool visualization and accurate localization using different US imaging platforms. An ultrasound image mid-plane detection accuracy of ±0.3 mm and a detectable tissue depth over 8.5 cm was achieved in the experiment. The system performance is tested under different configurations and system parameters. We also report the first experiment of arbitrary pattern injection to the B mode image and its application in accurate tool tracking.

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Related in: MedlinePlus

The local ultrasound amplitude measurement for mid-plane detection.a, b) the amplitude of the signal received by the active echo element verses the position of the probe. The depth of the US transmission beam focus is close to the catheter to probe distance, so the two plots are showing the signal distribution near the focus. a) The results with catheter perpendicular to the image plane (off-plane) b) catheter parallel to the image plane (in-plane). The error bar represents the standard deviation over 10 measurements, each time the translation stage moves from −9 mm to 9 mm, stops at the same sample positions and takes the signal amplitude reading.
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pone-0104262-g007: The local ultrasound amplitude measurement for mid-plane detection.a, b) the amplitude of the signal received by the active echo element verses the position of the probe. The depth of the US transmission beam focus is close to the catheter to probe distance, so the two plots are showing the signal distribution near the focus. a) The results with catheter perpendicular to the image plane (off-plane) b) catheter parallel to the image plane (in-plane). The error bar represents the standard deviation over 10 measurements, each time the translation stage moves from −9 mm to 9 mm, stops at the same sample positions and takes the signal amplitude reading.

Mentions: Once the AE element is triggered, the next step is to accurately align it to the mid-plane. Figure 7a, b shows the catheter received signal amplitude verses the imaging probe position. In the plot, the mid-plane position is indicated by the maximum of the signal amplitude. If the trigger level is set to a value close to the maximum, the active echo system can only be triggered when the element overlaps the mid-plane. For example, if a trigger is set to 90% of the maximum amplitude, a localizing accuracy of ±0.5 mm is expected from the Figure 7. In the water tank validation, the receiver gain is decreased until only one trigger per frame is achieved at the well aligned position. Then gradually move the catheter away from the mid-plane. At an offset of ±0.31 mm, the active echo spot disappears. The result is repeatable and stable over test runs. Using this method, a mid-plane localization accuracy of 0.3 mm can be achieved.


Active ultrasound pattern injection system (AUSPIS) for interventional tool guidance.

Guo X, Kang HJ, Etienne-Cummings R, Boctor EM - PLoS ONE (2014)

The local ultrasound amplitude measurement for mid-plane detection.a, b) the amplitude of the signal received by the active echo element verses the position of the probe. The depth of the US transmission beam focus is close to the catheter to probe distance, so the two plots are showing the signal distribution near the focus. a) The results with catheter perpendicular to the image plane (off-plane) b) catheter parallel to the image plane (in-plane). The error bar represents the standard deviation over 10 measurements, each time the translation stage moves from −9 mm to 9 mm, stops at the same sample positions and takes the signal amplitude reading.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4206269&req=5

pone-0104262-g007: The local ultrasound amplitude measurement for mid-plane detection.a, b) the amplitude of the signal received by the active echo element verses the position of the probe. The depth of the US transmission beam focus is close to the catheter to probe distance, so the two plots are showing the signal distribution near the focus. a) The results with catheter perpendicular to the image plane (off-plane) b) catheter parallel to the image plane (in-plane). The error bar represents the standard deviation over 10 measurements, each time the translation stage moves from −9 mm to 9 mm, stops at the same sample positions and takes the signal amplitude reading.
Mentions: Once the AE element is triggered, the next step is to accurately align it to the mid-plane. Figure 7a, b shows the catheter received signal amplitude verses the imaging probe position. In the plot, the mid-plane position is indicated by the maximum of the signal amplitude. If the trigger level is set to a value close to the maximum, the active echo system can only be triggered when the element overlaps the mid-plane. For example, if a trigger is set to 90% of the maximum amplitude, a localizing accuracy of ±0.5 mm is expected from the Figure 7. In the water tank validation, the receiver gain is decreased until only one trigger per frame is achieved at the well aligned position. Then gradually move the catheter away from the mid-plane. At an offset of ±0.31 mm, the active echo spot disappears. The result is repeatable and stable over test runs. Using this method, a mid-plane localization accuracy of 0.3 mm can be achieved.

Bottom Line: Accurate tool tracking is a crucial task that directly affects the safety and effectiveness of many interventional medical procedures.Compared to CT and MRI, ultrasound-based tool tracking has many advantages, including low cost, safety, mobility and ease of use.We performed ex vitro and in vivo experiments, showing significant improvements of tool visualization and accurate localization using different US imaging platforms.

View Article: PubMed Central - PubMed

Affiliation: Dept. of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, United States of America.

ABSTRACT
Accurate tool tracking is a crucial task that directly affects the safety and effectiveness of many interventional medical procedures. Compared to CT and MRI, ultrasound-based tool tracking has many advantages, including low cost, safety, mobility and ease of use. However, surgical tools are poorly visualized in conventional ultrasound images, thus preventing effective tool tracking and guidance. Existing tracking methods have not yet provided a solution that effectively solves the tool visualization and mid-plane localization accuracy problem and fully meets the clinical requirements. In this paper, we present an active ultrasound tracking and guiding system for interventional tools. The main principle of this system is to establish a bi-directional ultrasound communication between the interventional tool and US imaging machine within the tissue. This method enables the interventional tool to generate an active ultrasound field over the original imaging ultrasound signals. By controlling the timing and amplitude of the active ultrasound field, a virtual pattern can be directly injected into the US machine B mode display. In this work, we introduce the time and frequency modulation, mid-plane detection, and arbitrary pattern injection methods. The implementation of these methods further improves the target visualization and guiding accuracy, and expands the system application beyond simple tool tracking. We performed ex vitro and in vivo experiments, showing significant improvements of tool visualization and accurate localization using different US imaging platforms. An ultrasound image mid-plane detection accuracy of ±0.3 mm and a detectable tissue depth over 8.5 cm was achieved in the experiment. The system performance is tested under different configurations and system parameters. We also report the first experiment of arbitrary pattern injection to the B mode image and its application in accurate tool tracking.

Show MeSH
Related in: MedlinePlus