Imaging modalities such as endorectal ultrasonography (ERUS), pelvic magnetic
resonance (MRI) and computed tomography play a fundamental role in evaluating
recatl cancer preoperatively, planning surgical procedures, and selecting
patients for neoadjuvant therapy. Based on the best available evidence, ERUS
is recommended to accurately discriminate between T1 and T2 lesions, for low
rectal cancer, defined as 0-5cm from the anal verge, if local excision (with
transanal excision of transanal endoscopic microsurgery) is being considered.
MRI is the best modality to detect mesorectal fascia invasion and to predict
circumferential resection margin involvement. Both modalities have similar
limitations in distinguishing metastatic from bening lumph node in the
mesorectum. Due to higher panoramicity and multiplanar reconstruction,
three-dimensional ERUS allows to visualize the spatial relationship of the
rectal tumour in the context of the surrounding structures, improving the
accuracy of ultra-sonographic staging. Technological advances and
perspectives of ERUS under investigations are represented by real-time colour
elastography, Doppler US and contrast-enhanced US.
Three-Dimensional Endosonography for Staging of Rectal Cancer