Table 1.

Comparison of advantages and disadvantages between computed tomography (CT) and magnetic resonance (MR) imaging modalities

CT	MR
Uses ionizing radiation, high-dose procedure	Uses magnetic resonance, no ionizing radiation
Excellent spatial resolution	Excellent contrast resolution
Actual scanning time measured in seconds (typically <10 s)	Actual scanning time measured in minutes (typically 45 min)
Rarely requires general anesthetic in children	Frequently requires general anesthetic in children, depending on age
Excellent at showing calcification	Poor at showing calcification (signal void)
Poor at showing edema or pathological changes in specific tissue types	Excellent at showing edema and pathological changes in specific tissue types
Usually requires intravenous contrast (unless looking for calcification when not required)	Usually requires intravenous administration of contrast (but certain sequences can be tailored if this is contraindicated)
No known risk of nephrogenic systemic fibrosis (NSF)	Risk of NSF (rare, but renal patients believed to be at increased risk)
Widely available	Less widely available, especially for children
Less expensive	Expensive
Usually available as an emergency imaging technique	Not routinely available as an emergency technique
No significant contraindications	Contraindicated in patients with any internal ferrous objects (pacemakers, defibrillators, recent orthopedic metalware, other implanted metallic devices, metallic foreign bodies)
Open-style scanners	Generally quite enclosed scanners – risk of claustrophobia
Can only scan in one plane (but can do reconstructed images later)	Can scan in any plane
Few artefacts	Prone to artefacts depending on sequence type (especially motion artifact)