Nuclear magnetic resonance (NMR) imaging was used to evaluate pituitary and juxtasellar tumors in 37 patients representing a wide range of pathology . The value of the multiplanar facility of NMR is emphasized in providing accurate volumetric information and establishing the t opographical relation of tumors to adjacent structures. Current limitations of the method and possible future developments to improve diagnostic precision are discussed . In vestigat ion of pituitary and parapituitary

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... ons can be particularly exacting because c linical manifestations , including vi sual failure and endocrinological disturbances, may occur when the lesion is in its early stages. Appropriate management demands precise localization and a distinction among various pathologies so th at the appropriate operative route or field for irradiation can be chosen [1] . Early detection of suprasellar extension of pituitary adenomas is particu larly important in preventing visua l loss in patients undergoing medical treatment, especially when pregnancy occurs in women with prolactinomas, where there is a risk of acce lerated tumor expansion [2] . Follow-up stud ies are valu able in assessing the effects of radiotherapy or drug therapy on tumor size . After plain sku ll radiography , computed tomography (CT) in the transverse axial plane is usually used to diagnose and evaluate tumors in the pituitary region [3] [4] [5] . Despite the, high quality of imag es now avai lable, it is sometimes difficu lt to determine the precise extent of extrasell ar extension of pitu itary tumors and to diagnose microadenomas. In vasive procedures are often requ ired to confirm a suspected diag nosis of empty sell a syndrome and to establi sh the relationship of any mass to th e optic chiasm [6, 7] . Subjects and Methods Proton nuclear magnetic resonance (NMR) sc ans using steadystate free precession (SSFP) techniques were perform ed with a Picker resistive NMR unit on 10 normal vo lunteers and 37 pati ents with known pathology in the pitu itary region at the Queen 's Medical Centre, Nottingham. The cases studied comprised 12 chromophobe pituitary adenomas; five acromegalies; four craniopharyngiomas ; three cases each of prolactinoma, ju xtasellar aneurysm , and empty sell a syndrome; one case each of recurrent chordoma , hypoth alamic glioma, and nasopharyngeal carcinoma; and four co ll oidal cysts of the third ve ntric le. , Departm enl of Physics, University of Noltingham, Notting ham, En gland . 2 Presenl add ress : Pic k er Inl ern atio nal, Highl and Heig hts, OH 44 143. Proce dure Th e norm al pituitary gl and is isodense with brain and is best seen on sagittal secti on. It is our prac ti ce to obt ain a midline sag ittal scan and co mplement thi s with transverse and co ronal scans as appropri ate, usin g a slice thi c kn ess of 1 c m and an im age tim e of 2 min . A typi cal examin ati on of about eight sec ti ons takes 25 min . It is usuall y possible in no more th an three attempts to obtain a secti on in which at least part of th e third ve ntric le is in cluded with th e pituitary gl and below. Th e norm al gland is seen co ntrasted again st a variabl e quantity of marrow and air within th e bas isph enoid. Th e opti c c hi sam and optic nerves ca n be id entified within th e suprase ll ar ci stern s on sagittal and co ronal secti ons. Th e anatomy of th e suprasellar c istern s shown on transverse secti on matc hes th at seen with CT. Results NMR demonstrated-clearl y th e presence and size of pituitary adenom as. Its multi pl anar facilit y was most va luabl e in delin eatin g ex tra se ll ar extension. All tum ors visualized by NMR were denser than brain tissue an d all except one were homogeneous in texture. Alth ough th e bone of th e fossa co uld not be seen, th e deg ree of ex pansion of th e floor co uld be obse rved from th e co nfigurati on of th e inferi or margin of th e tum or on sagittal and co ron al sec ti ons. As A B Fig . 1.-Sag ittal (A) and ax ial Iransverse (8 ) NMR scans of massive invasive ch romophobe pil uilary show ext rase llar extension.