Magnetic resonance imaging for diagnosis and neoadjuvant treatment evaluation in locally advanced rectal cancer: A pictorial review

Figure 23 The effects of chemoradiotherapy on a rectal tumor and circumferential resection margins. T2-weighted axial magnetic resonance images in different patients show baseline and post-CRT images on upper and lower series, respectively. A: Overstaging due to thick, hypointense tissue infiltration at the mesorectal fascia (arrow) in ypT2 rectal tumor with no MRF invasion; B: In ypT3 rectal tumor with no MRF invasion, thick fibrous retractions of the tumor, suspicious for CRM positivity (arrow); C: Rectal mass is markedly shrunken with low-signal-intensity tissue infiltration at the mesorectal fascia (arrow). At surgery, there was tumor invasion of the mesorectal fascia. CRM: Circumferential resection margins; MRF: Mesorectal fascia; CRT: Chemoradiotherapy.