Endoscopic Ultrasound and Contrast Enhancement for Staging and Evaluation of Angiogenesis of Left Sided Colon Cancers

All patients will be evaluated by EUS and CE-EUS, using radial EUS instruments. The EUS scope will be inserted under direct vision, passed by the tumour and examination should begin during withdrawal at 7.5 MHz. The tumour will be characterized describing its echogenicity, echo structure, size, extent into the bowel wall and surrounding structures, and it will be staged using the modification of the TNM classification, based on a five-layer intestinal wall model. The presence/absence of power Doppler signals will be noted. For CE-EUS parameters for objective measurement of tumour perfusion will include maximum intensity of enhancement, mean transit time, time to peak (wash-in time), wash-in slope, area under the curve, representing indirectly blood flow or blood volume in CRC patients.