Determining the Efficiency of Emboli Detection with Ultrasonography
Open Access
- Author:
- Pearson, Cara Emily
- Area of Honors:
- Biomedical Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Dr. Keefe B Manning, Thesis Supervisor
Dr. Nanyin Zhang, Thesis Honors Advisor - Keywords:
- Cardiovascular Fluid Dynamics
Ultrasound
Emboli
Pulmonary Embolism
Pan-Tompkins Algorithm
Doppler Effect
High Intensity Transient Signals
Thrombus
Reynolds number
Blood
Hemostasis
Coagulation Cascade
Ultrasonography
Heart Attack
Stroke
Artificial Heart - Abstract:
- In the United States, pulmonary embolism (PE) accounts for 100,000-200,000 deaths each year. Left untreated, 30% of PE patients will die from the disease. Instead of treating the pathology when it occurs, prevention and identification beforehand of emboli in the systemic and pulmonic vasculature have the ability to improve future health outcomes. Currently, it has been shown that Doppler ultrasonography has the ability to detect microembolic material as high intensity transient signals (HITS) in the brain. Doppler ultrasonography detection of emboli is highly dependent upon the composition and size of the embolus, the flow rate, and the sonographer, among other variables. Therefore, the objective of this experiment was to determine the efficiency of Doppler ultrasound at detecting non-deformable clots of various sizes over a range of physiological conditions in order to better quantify the technology. This study measured the Verasonics Research Ultrasound system’s detection efficiency with Doppler Ultrasonography using rigid beads of 2.3 mm, 3.2 mm, and 4.8 mm diameters under physiological conditions analogous to the iliac vein and carotid artery. A Reynolds number of 200 and 500 were chosen for the iliac vein and carotid artery respectively in accordance with pre-existing literature. This study determined the embolus detection efficiency and accuracy of the Verasonics Research Ultrasound system with Doppler ultrasonography. The longitudinal position was determined to be better statistically at detecting emboli in flow as compared to the cross-sectional position. The longitudinal position afforded a method for detecting emboli in flow with a sensitivity of 77.8%, a precision of 71.3%, and an accuracy of 72.9%. The sensitivity determined with the quantitative methods in this study was comparable to literature values using a human sonographer, which is considered the gold standard. Reynolds number was determined not to have a significant effect on detection. In a few specific cases, bead size was determined to have a significant effect on detection, however there was no discernable trend. Future studies should be conducted to refine the methods and to increase the application of this protocol.