Table 1.

The Organ Procurement and Transplantation Network (OPTN) recommendations for minimum technical specifications for dynamic contrast-enhanced MRI of the liver.

Feature	Specification	Comment
Scanner type	1.5 Tesla or greater main magnetic field strength	Low field magnets are not suitable
Coil type	Phased array multichannel torso coil	Unless patient-related factors precludes use (e.g. body habitus)
Minimum sequences	Precontrast and dynamic post gadolinium
	T1-weighted gradient echo sequence (3D preferable)
	T2-weighted (with and without fat saturation)
	T1-weighted in- and out-of-phase imaging
Injector	Dual chamber power injector	Bolus tracking is recommended
Contrast injection rate	2–3 mL/s of extracellular gadolinium chelate that does not have dominant biliary excretion	Preferably resulting in vendor-recommended total dose
Mandatory dynamic phases on contrast enhanced MRI (comments describe typical hallmark image features)	Precontrast T1-weighted Late arterial phase Portal venous phase Delayed phase	Do not change scan parameters for postcontrast imaging Artery fully enhanced, beginning contrast enhancement of portal vein Portal vein enhanced, peak liver parenchymal enhancement, beginning contrast enhancement of hepatic veins Variable appearance, >120 s after initial injection of contrast
Dynamic phases (timing)	The use of a bolus tracking method for timing contrast arrival for late arterial phase imaging is preferable. Portal venous phase (35–55 s after initiation of late arterial phase scan), delayed phase (120–180 s after initial contrast injection)
Slice thickness	5 mm or less for dynamic series, 8 mm or less for other imaging
Breath-holding	Maximum length of series requiring breathhold should be about 20 s with a minimum matrix of 128×256	Compliance with breathhold instructions is very important, technologists need to understand the importance of patient instruction before and during scan

3D, three-dimensional; MRI, magnetic resonance imaging.