From: Magnetic resonance imaging (MRI) in rectal cancer: a comprehensive review
Plane | Advantage | Disadvantage | Usage |
---|---|---|---|
Sagittal (orthogonal) | Easy for measuring tumor height and length. Best for assessment of involvement of midline organs and structures | Structures slightly lateral to midline not easily assessed especially in female patients | Easily reproducible. Recommended |
Axial (orthogonal) | Easily recognizable by clinicians. Easy for comparison with MRI or other imaging modalities, especially comparison of lymph nodes. Often best view of inguinal lymph nodes | Due to funnel-shaped form of pelvic floor and anterior curve of rectosigmoid, not enough for adequate detailed analysis in many cases | Easily reproducible. Recommended |
Coronal orthogonal | None | Takes time of more important images | Not recommended |
Semi-coronally parallel to anal canal | Visually informative for surgeons in low rectal tumors | Can be the same as perpendicular to pelvic floor | Not essential |
Perpendicular to rectal wall | Provides best differential of T1, T2 and minimal T3. Has to be repeated at all areas where distinction between T3 and T1-2 is important | Needs either capable technicians or presence of radiologists at the time of imaging | Essential |
Perpendicular to anterior mesorectal fascia | For anterior tumors or tumors with anterior component, especially in female subjects | Sometimes not necessary in cases of obvious tumor growth into anterior structures | Important in selected cases |
Perpendicular to pelvic floor | For tumors growing dorsally and laterally close to pelvic floor. Can provide coverage of mesorectal lymph nodes | Not necessary in all cases | Important in selected cases |
Perpendicular to anal canal | Most important plane for low tumors at the level of pelvic floor or lower down | Not essential for tumors completely above the pelvic floor | Not essential for tumors completely above the pelvic floor |