Colonography by CT, MRI and PET/CT combined with conventional colonoscopy in colorectal cancer screening and staging

Table 1 Characteristics of medical images in detecting CRC

Modalities	Characteristics
DCBE	Cost-effective, efficient, safe, could be performed and interpreted by GI radiographers to reduce waiting
Colonoscopy	Cost-effective, endoscopic resection of polyps, endomicroscopy opening the way of in vivo molecular imaging
CTC	Less uncomfortable, minimally invasive, with radiation exposure, 3D virtual dissection of colon,
MRC	Limited bowel preparation, unpleasant rectal tube, filling colon with saline and contrast, no radiation
PET/CTC	Accurate whole-body tumor staging, with integrated morphological and functional images, more irradiation

Table 2 Comparison of medical image modalities’ values in colonography

Modalities	Specificity	Sensitivity	Accuracy
DCBE	+	+	-
Colonoscopy	+++	++	+++
CTC	+	++	_
MRC	++	+	+
ET/CTC	++	++	+++

Legend: _- poor; + fair; +++ good; ++++ excellent.