Magnetic resonance imaging: Basic concepts

Abstract

This chapter is dedicated to basic unenhanced, and static enhanced MRI. Distinction is made between imaging for local staging and for tissue characterization purpose, as well as between what is essential, what should be avoided, and what are useful additional techniques. An appropriate choice of imaging planes is suggested, stressing the importance of axial plane imaging for local staging. For unenhanced MRI SE T1-WI and an optimal fluid-sensitive sequence are mandatory. The added value of fat-suppressed T1-WI for tissue characterization is discussed. Enhanced MRI is not always mandatory but usually improves the evaluation of the internal structure of a tumor. Nonfat-suppressed-enhanced T1-WI is very useful for surgical planning. Fat-suppressed-enhanced T1-WI is very popular, although not a routine requirement. Its advantages, disadvantages, and possible misinterpretation of Gd uptake are explained. Subtraction images might be useful to differentiate between a subacute hematoma and a hemorrhagic tumor. Finally the limitation of static enhanced MRI and the added value of dynamic enhanced MRI are briefly discussed.