- Identification of excessive production of cortisol,
- Differential diagnosis of options syndrome and
- Establishing the localization of the main pathological process.
Differential diagnosis draw between pituitary or ectopic Cushing's syndrome (ACTH-dependent options), and adrenal Cushing's syndrome (ACTH-independent version). Differential diagnosis is based on data from laboratory studies. To identify the main pathological process using imaging techniques:
- MRI is used to estimate the size and prevalence of pituitary tumors. CT less informative.
- CT is used to determine the location and size of adrenal lesions (hyperplasia or tumor). MRI less informative.
- Scintigraphy with 131I-adrenal cholesterol.
If carried out adrenal scintigraphy with 131I-cholesterol, then:
- When pituitary and ectopic Cushing's syndrome, excessive secretion of ACTH leads to adrenal hyperplasia, which is 70% of cases accompanied giperkortizolemiey. On scintigrams seen symmetrically enlarged adrenal glands, the distribution of tags equal; after dexamethasone suppression of adrenal glands are not visualized.
- Adrenal Cushing syndrome due to excessive secretion of cortisol adenoma or adrenal hyperplasic cloth. When a unilateral adenoma, only one adrenal gland is visualized, since the excess secretion of cortisol suppresses tumor secretion of cortisol in the contralateral adrenal gland. When node hyperplasia (bilateral lesion) can see both the adrenal gland, but the distribution of tags is uneven.
- Cancer of the adrenal glands, are generally not visualized.
- The remains of the adrenal glands can be detected after partial bilateral adrenalectomy, produced at the pituitary Cushing's syndrome.
- Sometimes visualized accessory adrenal tissue.
