Role of preoperative CT colonography in patients with colorectal cancer

Table 1 Computed tomography colonography scanning technique for a 64-slice scanner¹

	Preoperative CTC	Screening CTC
IV contrast media	Yes	No
Patient position	Prone (unenhanced), supine (portal phase)	Supine, prone
Collimation	32 mm × 0.6 mm	32 mm × 0.6 mm
Tube voltage	120 kV	120 kV
Tube current	140 eff mAs (unenhanced), 200 eff mAs (enhanced)	50 eff mAs
Tube rotation time	0.5 s	0.5 s
Pitch	1.4	1.4
Section width	1 mm	1 mm
Reconstruction increment	1 mm	1 mm

¹Scan parameters for Sensation 64 (Siemens, Erlangen, Germany). CTC: Computed tomography colonography.

Table 2 TNM staging of colorectal cancer¹

Stage	Description
Primary tumor (T)
T1	Tumor invades submucosa
T2	Tumor invades muscularis propria
T3	Tumor invades through the muscularis propria into the subserosa, or into the non-peritonealized pericolic tissues
T4	Tumor directly invades other organs or structures and/or perforates the visceral peritoneum
Regional lymph nodes (N)
N0	No regional lymph node metastases
N1	Metastases in 1-3 regional lymph nodes
N2	Metastases in ≥ 4 regional lymph nodes
Distant metastases (M)
M0	No distant metastases
M1	Distant metastases

¹American Joint Committee on Cancer (AJCC).