14 MRI of primary rectal cancer v2

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: <5mm
T3b: 5-10mm
T3c: >10mm


T3 tumor

T3b

T3c

T4 tumor


Rectal cancer division

Low <5cm, Midle: 5-10cm, High: >10cm.
Distance > 1mm from CRM or MRF


Cliquez pour modifier les styles du texte du masque
Deuxième niveau
Troisième niveau
Quatrième niveau
Cinquième niveau

LAR: Low Anterior Resection, ISR: InterSphincter Resection
APR: AbdominoPeritoneal Resection
EAS: External Sphincter Complex, LA: Levator Ani, IAS: Internal Anal 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


Peritoneal reflection


Anal sphincter


Pelvic sidewall


Vascular invasion


Lymph nodes involvement


Mesorectal lymph node involvement


Pelvic sidewall lymph node involvement


Problem of angulation