Table 1.

Advantages, limitations, future developments and recommendations for the use of each technique.

Techniques	Advantages	Limitations	Future developments	Recommendations
CT scan	Easily available Noninvasive	Lack of specificity Irradiant Nephrotoxic	Not planned	Eventually
MRI	Nonirradiant Noninvasive	Lack of specificity Expensive Hardly available	Not planned	Not recommended
US	Noninvasive Easily available Cheap	Lack of specificity	Not planned	Not recommended
CEUS	Sensitive Specific Noninvasive	Limited to lower GI acute GVHD Specific device Trained physician	Prospective studies	Not available in routine
PET/CT	Sensitive Specific Early detection Noninvasive	Expensive Irradiant	Prospective studies	Useful in some patients
WCE	Noninvasive Sensitive	Bowel preparation Lack of specificity	Prospective studies	Useful in some patients
eCLE and pCLE	Sensitive Specific Early detection	Invasive Specific device Trained physician	Prospective studies	Not available in routine

CT scan: computed tomography scan; MRI: magnetic resonance imaging; US: ultrasonography; CEUS: contrast-enhanced ultrasound; GI acute GVHD: gastrointestinal acute graft-versus-host disease; WCE: wireless video-capsule endoscopy; eCLE: endoscope-based confocal laser endomicroscopy; pCLE: probe-based confocal laser endomicroscopy.