Magnetic resonance imaging in rectal cancer: A surgeon’s perspective

Table 1 Metanalysis of magnetic resonance imaging staging of rectal cancer-Al-Sukhni et al[27]

	Sensitivity% (95%CI)	Specificity% (95%CI)	DOR (95%CI)
T stage	87 (81-92)	75 (68-80)	20.4 (11-37)
N stage	77 (69-84)	71 (59-81)	8.3 (4.6-14.7)
CRM	77 (57-90)	94 (88-97)	56.1 (15-205)

DOR: Diagnostic odds ratio; CI: Confidence interval; CRM: Circumferential resection margin.

Table 2 Classification of low rectal cancers Shihab et al[41]

Level	Tumor height	Tumor depth	Operative plane
1	Tumor height between levator origin and puborectalis sling	Confined to muscle	LAR/intersphincteric APE
		Beyond muscle	LAR/intersphincteric APE
		Tumor < 1 mm MRF/levator	Extralevator APE
		Tumor extending beyond levator	Extralevator APE
2	Tumor at or below puborectalis sling	Submucosal/partial thickness muscle	LAR/intersphincteric APE
		Full thickness muscle	Extralevator APE
		In to intersphincteric plane	Extralevator APE
		In to external sphincter	Extralevator APE
		Beyond external sphincter into ischiorectal tissue	Pelvic exenteration

APE: Abdominoperineal excision; LAR: Low anterior; MRF: Mesorectal fascia.

Table 3 Classification low rectal cancer (Taylor et al[34] 2008)

Stage
1	Tumor confined to bowel wall, outer muscle intact
2	Tumor occupies muscle coat but does not enter intersphincteric plane
3	Tumor enters intersphincteric space or lies within within 1 mm of levator muscle
4	Invades external anal sphincter or is 1 mm or beyond levator with/without adjacent organ involvement

Table 4 Post long course chemoradiotherapy magnetic resonance imaging 2-Parameters are assessed on post treatment magnetic resonance images

	Pre treatment	Post treatment
Height of tumor from anal verge
Length of tumor
Tumor stage (sub stage based on extramural spread)
Nodal spread
Nodes pelvic sidewall
Involvement peritoneal reflection
Distance to potential CRM
Depth of maximum extramural spread (distance from outer edge of muscularis propria) tumor and fibrosis separately
Extramural venous invasion

MRI tumor regression grade, Grade V: No response (same as original tumor); Grade IV: Slight response (litte area of fibrosis/mucin, mostly tumor); Grade III: Moderate response (more than 50% fibrosis, mucin but mostly tumor); Grade II: Good response (dense fibrosis, no obvious residual tumor); Grade I: Radiological complete response (no evidence of ever treated tumor); CRM: Circumferential resection margin.