Nuclear magnetic resonance imaging of the region of the sella turcica.

Nuclear magnetic resonance (NMR) imaging is a versatile technique which has proved more sensitive in the detection of perisellar lesions than CT. A multiplanar facility, the demonstration of blood flow, and the lack of bone artefacts are its main advantages in this respect. Limitations are seen in its inability to identify small calcifications and to distinguish clearly perifocal oedema and tumour especially in malignant lesions. Relatively thick slices of 5-10 mm make the detection of microadenomas very difficult, mainly because of partial volume effects. T1 and T2 values alone are not sufficient to provide specific diagnosis. No reliable criteria have been determined yet, which would indicate the quality of pathological involvement of peritumorous structures by tumours of the sella region. At present NMR still plays a more complementary role to CT in the evaluation of this complex anatomical area. We are confident that with future technical refinements NMR will be able to replace ionizing radiation for the diagnostic imaging of the sella.