Table 3.

Method of classification of pseudotumours found on MARS-MRI

Pseudotumour category	Wall	Contents	Shape
Class 1	Thin walled	Fluid like:	Flat with walls mainly in apposition
		T1 - hypointense
		T2 - hyperintense
Class 2A	Thick walled or irregular	Fluid like:	Not flat and more than 50% of the walls are not in apposition
		T1 - hypointense
		T2 - hyperintense
Class 2B	Thick walled or irregular	Atypical fluid:	Any size
		T1 - hyperintense
		T2 - variable
Class 3	Solid	Mixed signal	Any size

MARS = metal artifact reduction sequence.