Cancers trigger angiogenesis in neighbouring tissue and recruit new blood vessels to grow and metastasise. Therefore, therapeutic and diagnostic strategies have been moving towards targeting tumour neoangiogenesis as a key factor in the progress and assessment of the disease. High-frequency ultrasound (HF-US) offers a low-cost and non invasive approach for studying the efficacy of antiangiogenic therapies in the pre-clinical setting. However, there is little information in the literature about the performance of HF-US in vivo in regards of evaluating tumour vascularity and its correlation with microvessel density (MVD). The aim of this thesis was to optimise a HF-US system to investigate its ability to visualise and to quantify tumour parameters, particularly tumour blood flow, in colorectal cancer (CRC) mouse model. The performance of a HF~US (~ 25 MHz) system was evaluated in vitro using test objects in order to assess the ability of the system to study the normal mouse colon and to optimise its scanning parameters for imaging tumour blood flow. This was followed by two in vivo approaches. Firstly, the feasibility of using HF-US in depicting the mouse colon and measuring its thickness accurately and reproducibly as a potential model for CRC was established. Secondly, the performance of different HF-US blood flow imaging techniques was compared in a CRC xenograft model and correlations between the different ultrasonic vascular parameters and MVD determined.