Coronary artery disease (CAD) is one of the leading causes of death globally. CAD is predominantly the result of atherosclerosis, the accumulation of plaque within the arteries. Untreated atherosclerosis can result in major adverse cardiovascular events including death. Given the prevalence of the disease and its complex, multi-faceted symptoms, tools for stratifying risk and guiding minimally-invasive interventions are essential. When patient first presents with cardiac symptoms, computed tomography coronary angiography (CTCA) is used to evaluate coronary arteries non-invasively. However, some of these CTCA images are non diagnostic due to cardiac motion during image acquisition. Some patients with coronary pathology will then be sent to the cardiac catheterization lab for further assessment and possible stenting. In the cath lab, catheter coronary angiography (CCA) is currently the gold standard for guiding percutaneous coronary intervention (PCI). Intravascular ultrasound (IVUS) imaging is used to provide anatomical (morphological) imaging during PCI. However, current side-viewing IVUS does provide imaging of physiology and must cross the lesion in order to image it. Alternatively, forward-viewing IVUS could be used to evaluate lesion structure, composition, and hemodynamics within the procedure without crossing the lesion. In particular, it could also image a known indicator of risk of plaque rupture, wall shear stress (WSS). Three ultrasound array transducers were developed to improve risk stratification in patients with coronary artery disease: 1) a CT-compatible ultrasound array for improved CTCA gating, 2) a proof of concept 140 element count FV-IVUS imaging array, and 3) an improved and cabled 136 element FV-IVUS catheter for intra-coronary color flow and wall shear stress (WSS) estimation.