Assessment of T staging and mesorectal fascia status using high-resolution MRI in rectal cancer with rectal distention

Table 1 Definitions used for staging rectal cancer

Histopathologic examination	MRI
pT1: Tumor invades the submucosa	MRT1: Tumor signal intensity is confined to the submucosal layer
pT2: Tumor invades the muscularis propria	MRT2: Tumor signal intensity extends into the muscle layer, with loss of the interface between the submucosa and circular muscle layer
pT3: Tumor invades through the muscularis propria into the subserosa or into the nonperitonealized pericolic or perirectal tissues	MRT3: Tumor signal intensity extends through the muscle layer into the perirectal fat, with obliteration of the interface between muscle and perirectal fat
pT4: Tumor directly invades other organs or structures or perforates the visceral peritoneum	MRT4: Tumor signal intensity extends into an adjacent structure or viscus

Table 2 Accuracy for each T stage (n/n)%

	≤pT2 (n = 20)	pT3 (n = 42)	pT4 (n = 5)
Accuracy	(60/67) 89.6	(57/67) 85.1	(64/67) 95.5
Sensitivity	(14/20) 70.0	(38/42) 90.5	(5/5) 100
Specificity	(46/47) 97.9	(19/25) 76.0	(59/62) 95.2
PPV	(14/15) 93.3	(38/44) 86.4	(5/8) 62.5
NPV	(46/52) 88.5	(19/23) 82.6	(59/59) 100

PPV: positive predictive value; NPV: negative predictive value.