Browsing by Author "ALZAHRANI, Adel"

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Evaluation of Tomographic 3D Ultrasound for the Assessment of Vascular Pathology
(2023-05-31) ALZAHRANI, Adel; Aslam, M
Tomographic 3D ultrasound (t3DUS) is a promising imaging technique for quantifying vascular diseases by measuring the degree of stenosis and plaque volume. However, its accuracy and reliability for the assessment of vascular diseases need to be investigated. Therefore, this thesis aims to assess the accuracy and reproducibility of t3DUS for quantifying vascular diseases, including grading stenosis and measuring plaque volume in-vitro and in-vivo. A literature review was performed to evaluate the use of three-dimensional ultrasound (3DUS) for assessing carotid stenosis in patients with carotid diseases showing that 3DUS is more accurate in quantifying carotid diseases and has a low level of inter and intra-observer variability when compared to 2DUS. However, it requires prolonged time for images to be reconstructed into 3DUS, which may currently limit its use in clinical practice. The analysis from the in-vitro study on the vascular phantom, including channels with different grades of stenosis, demonstrated that t3DUS has an excellent inter-operator agreement with low variability and is more accurate than 2DUS for grading stenosis when compared to the reference values with an Intra-Class Correlation (ICC) value of 0.96 (95% confidence interval (CI) 0.90 – 0.98, p <0.001. Based on these findings, two clinical studies were conducted investigating the reproducibility and accuracy of t3DUS for measuring carotid plaque volume (CPV) within the internal carotid artery (ICA) in patients undergoing carotid endarterectomy (CEA) (n=25), and the potential benefits of t3DUS in providing more precise measurement of stenosis in the superficial femoral artery (SFA) in patients with the peripheral arterial disease (PAD) (n=50). The results showed an excellent agreement level between t3DUS and reference test (i.e., Ex-vivo carotid plaque volume from carotid endarterectomy specimen) and intra-observer agreement in measuring carotid plaque volume. This result demonstrates that t3DUS can measure the disease severity of SFA in patients with lower limb arterial disease with a correlation value (r) = 0.99, p<0.001. The findings of this thesis indicated that t3DUS is a reliable and reproducible method for quantifying vascular diseases, including grading stenosis and measurements of CPV. Further research investigating the potential of the added value of t3DUS in assessing the different ranges of vascular diseases, including aneurysms, arteriovenous fistula (AVF) for haemodialysis access, and venous mapping, should be considered.
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