Adrenal gland CT – X-ray tomographic visualization of the morphological structure and pathological processes of the adrenal glands. With a high degree of probability, it allows to differentiate the nature of the neoplasm (adenoma, cyst, pheochromocytoma, adrenocortical cancer, metastases). Tomograms assess the position, contours, shape, structure, density, size of the adrenal glands and additional formations, the presence of enlarged lymph nodes.
Indications
Various kinds of adrenal neoplasms at the stage of preclinical symptoms are accidental findings with CT in 0.3% of the subjects. Targeted adrenal gland CT allows to identify organ-specific formations: adenomas, pheochromocytomas, cysts, malignant (including metastatic) tumors of the adrenal glands, as well as hematomas, cortical hyperplasia, lipomas, glandular myelolipomas. Dynamic contrast study is aimed at morphological differentiation of pathological findings. The ability to accurately determine the topographic features of tumors and their location in the gland makes CT an indispensable study before planning operations and the scope of intervention. CT guidance is used to perform a fine needle aspiration biopsy of the adrenal glands.
Contraindications
Contraindications to adrenal gland CT are pregnancy, recent X-ray contrast examination with barium (irrigoscopy, etc.), taking bismuth preparations, the inability to remain motionless during the study. Adrenal gland CT with contrast enhancement is excluded in case of allergy to iodine preparations, severe forms of kidney disease and diabetes mellitus.
Methodology of conducting
Before examining the adrenal glands, the patient is asked to remove metal products and clothing with metal parts from the body. With CT, visualization of glandular tissues is achieved using X-rays and computer data processing. The patient is placed on a motorized tomograph table connected to a scanner. When the beam tube moves, multiple layer-by-layer images are taken. If necessary, in addition to native scanning, a study with intravenous contrast enhancement (Hypac, Omnipac, Ultravist) is performed. After processing the X-ray information in a computer program, the images can be printed on film or recorded on a digital medium.
During the adrenal gland CT, the patient is required to maintain a stationary position. Despite the fact that the patient remains alone in the research room during the scan, he is constantly in the field of view of the laboratory assistant and can contact the staff via audio contact. The procedure lasts on average about 30 minutes. At the end of contrast CT, an enhanced drinking regime is recommended for the speedy removal of the iodine-containing drug.
Interpretation of results
Based on the adrenal gland CT, a non-invasive assessment of the contours, shape, structure, size, density of formations, the presence of inclusions, calcium salts, necrosis zones, as well as altered lymph nodes is performed. Normally, the usual location of the glands is lost. The shape of the right adrenal gland is more often linear, the left one is V or Y-shaped, the contours are smooth and clear, the density is not changed, the structure is homogeneous, the dimensions are not increased. No changes are detected in the paranephral tissue. Enlarged lymph nodes are not detected at the examined level. After the attempted contrast, both adrenal glands accumulate contrast evenly.
Glandular adenomas are characterized by an oval or rounded shape, smooth outlines of contours, homogeneous or moderately heterogeneous structure. The sensitivity of CT when detecting adenomas is 98%. With adrenal cysts, clear rounded thin-walled formations with homogeneous contents are determined on CT. The walls of cysts may have calcification areas, the density of their contents does not change when contrasting. CT imaging of adrenal lipomas is characterized by a rounded shape, sharp contours, moderate heterogeneity of the structure due to fatty inclusions. Lipomas do not deform the adrenal gland and are clearly separated from the unchanged tissue.
Adrenal hematomas look like encapsulated oval formations with uneven contours and heterogeneous structure due to the presence of clots. The pheochromocytomas detected by CT have a heterogeneous structure, rounded or oval shape, smooth contours, and a well-defined capsule. The absorption of X-rays increases with contrast. CT-signs of malignant formations of the adrenal glands are significant tumor sizes, heterogeneity of the structure with foci of different densities, blurred contours, calcification zones, an increase in paravasal lymph nodes, a high density of tumor tissues compared with benign findings, sometimes bilateral localization.
Complications
In general, adrenal gland CT is a safe and painless procedure. The patient’s movements during the scan, metal implants in the projection of the study area can distort the results of the study. After applying a contrast agent, the appearance of a metallic taste in the mouth is sometimes noted. To exclude allergies to iodide contrast, an anamnesis is found out before the start of CT, a test test for the tolerability of the drug is carried out. The risks associated with radiation exposure during adrenal gland CT are insignificant.
