MRI of primary rectal cancer PhD MD Hoang Dinh Au Background (1) • High-resolution T2-weighted imaging is the key sequence in the magnetic resonance (MR) imaging evaluation of primary rectal cancer This sequence generally consists of thin-section (3-mm) axial images obtained orthogonal to the tumor plane, with an in-plane resolution of 0.5–0.8 mm Normal anatomy MRI Imaging plan: incorrect angulation Imaging plan Background (2) • • • • Differentiate T2 from T3 tumors Deep of tumor invasion outside the muscularis propria Relationship of tumor to the mesorectal fascia, anal sphincter, pelvic sidewall Pelvic nodal involvement 1) Assessement of the primary tumor T2 tumor T3 tumor • • • T3a: 10mm T3 tumor T3b T3c Mesorectal lymph node involvement Pelvic sidewall lymph node involvement Problem of angulation Correct angulation Value of HR multiplanar imaging Routine vs HR multiplanar imaging Routine vs HR imaging Benefit of using rectal gel Imaging quality: 3D HR T2w Anterior saturation band Optimization of imaging quality Diffusion weigted imaging Suggested checklist for use prior to MR Imaging of rectal cancer Protocol MRI Cliquez pour modifier les styles du texte du masque Deuxième niveau Troisième niveau Quatrième niveau Cinquième niveau ... imaging evaluation of primary rectal cancer This sequence generally consists of thin-section (3-mm) axial images obtained orthogonal to the tumor plane, with an in-plane resolution of 0.5–0.8 mm Normal... Sphincter PR: Puborectalis, ISP: Intersphincter Plan 2) Deep of tumor invasion outside the muscularis propria Invasion of T3 tumors 3) Relationship of tumor to other anatomic structures Mesorectal fascia... muscularis propria Relationship of tumor to the mesorectal fascia, anal sphincter, pelvic sidewall Pelvic nodal involvement 1) Assessement of the primary tumor T2 tumor T3 tumor • • • T3a: