The optimal imaging of adrenal tumours: a comparison of different methods

    1. Karel Pacak3
    1. Department of Endocrinology, Elena Venizelou Hospital, Athens GR-11521, Greece
    2. 1Departments of Radiology and
    3. 2Endocrinology, St Bartholomew’s Hospital, West Smithfield, London EC1A 7BE, UK
    4. 3Section on Medical Neuroendocrinology, Reproductive Biology and Medicine Branch, National Institute of Child Health and Human Development, National Institutes of Health, Building 10, CRC, 1 East, Room 1-3140, 10 Center Drive, MSC-1109, Bethesda, Maryland 20892-1109, USA
    1. (Correspondence should be addressed to K Pacak; Email: karel{at}


    Computed tomography (CT; unenhanced, followed by contrast-enhanced examinations) is the cornerstone of imaging of adrenal tumours. Attenuation values of <10 Hounsfield units on an unenhanced CT are practically diagnostic for adenomas. When lesions cannot be characterised adequately with CT, magnetic resonance imaging (MRI) evaluation (with T1- and T2-weighted sequences and chemical shift and fat-suppression refinements) is sought. Functional nuclear medicine imaging is useful for adrenal lesions that are not adequately characterised with CT and MRI. Scintigraphy with [131I]-6-iodomethyl norcholesterol (a labelled cholesterol analogue) can differentiate adrenal cortical adenomas from carcinomas. Phaeochromocytomas appear as areas of abnormal and/or increased uptake of [123I]- and [131I]-meta-iodobenzylguanidine (a labelled noradrenaline analogue). The specific and useful roles of adrenal imaging include the characterisation of tumours, assessment of true tumour size, differentiation of adenomas from carcinomas and metastases, and differentiation of hyperfunctioning from non-functioning lesions. Adrenal imaging complements and assists the clinical and hormonal evaluation of adrenal tumours.

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