Fig. 5
From: Role of diffusion-weighted MRI in diagnosis and post therapeutic follow-up of colorectal cancer
A 54-year-old male presented with bleeding per rectum (colonoscopy and biopsy revealed rectal poorly differentiated adenocarcinoma). Pretreatment study (A to F) revealed upper third rectal mass at the right anterolateral wall with no invasion to the mesorectal fat (measured 2 × 1 × 1.9 cm). It displayed intermediate signal in sagittal and axial T2-weighted images (A, B) and intermediate signal in T1-weighted images (C) with mild homogenous enhancement in post contrast images (D). The lesion appeared bright in DWIs (E) and turned dark in the ADC map (F), with ADC value 0.63 × 10−3 mm2/s, indicating restricted diffusion. Posttreatment study after chemo and radiotherapy (G to L) revealed minimal low signal at the previous tumor site in sagittal, axial T2WIs (G, H) and axial T1WI (I) with no enhancement in post contrast images (J). There is no detectable altered signal at the site of abnormality in DWIs (K) and ADC map (L), with ADC value 1.5 × 10−3 mm2/s. Colonoscopy and biopsy revealed presence of fibrosis at the rectal wall with no evidence of residual tumor cells (complete response)