Cross-sectional imaging work-up of adrenal masses

Abstract

Advances in medical imaging with current cross-section modalities enable non-invasive characterization of adrenal lesions. Computed tomography (CT) provides characterization with its non-contrast and wash-out features. Magnetic resonance imaging (MRI) is helpful in further characterization using chemical shift imaging (CSI) and MR spectroscopy. For differentiating between benign and malignant masses, positron emission tomography (PET) imaging is useful with its qualitative analysis, as well as its ability to detect the presence of extra-adrenal metastases in cancer patients. The workup for an indeterminate adrenal mass includes evaluation with a non-contrast CT. If a lesion is less than 10 Hounsfield Units on a non-contrast CT, it is a benign lipid-rich adenoma and no further work-up is required. For the indeterminate adrenal masses, a lipid-poor adenoma can be differentiated from a metastasis utilizing CT wash-out features. Also, MRI is beneficial with CSI and MR spectroscopy. If a mass remains indeterminate, PET imaging may be of use, in which benign lesions demonstrate low or no fluorodeoxyglucose activity. In the few cases in which adrenal lesions remain indeterminate, surgical sampling such as percutaneous biopsy can be performed.

Adrenal Intravascular Papillary Endothelial Hyperplasia

“…Different tissue types with different attenuation will have different Hounsfield values, with distilled water being zero. 8 Based on this scale, tissue composition of structures, like masses, for instance, can be inferred from CT images. 8 The etiology of adrenal masses is often determined with minimal error utilizing …”

“…Each case must be evaluated on an individual basis, but in general, nonfunctional masses less than 4 cm with benign characteristics on imaging may be followed with serial imaging and laboratory evaluation. [6][7][8] For nonfunctional lesions in the range of 4 to 6 cm with benign imaging characteristics, short interval monitoring is appropriate. Adrenal masses greater than 6 cm should be excised after hormonal workup.…”

“…[3][4][5][6] In our case, an incidentaloma found on imaging warranted workup for much more common and potentially life-threatening etiologies. 2,7,8 The evaluation of an adrenal incidentaloma has been well-described and must include a functional workup as well as an appropriate dedicated cross-sectional imaging study. The decision to proceed with surgical excision is based on the risk of malignancy and the results of the functional workup.…”

“…Radiologic imaging of adrenal masses, specifically density or Hounsfield units (HU) assessment provides critical information in clinical decision making. 8 The HUs are a measure of attenuation coefficient of X-rays as they pass through tissues. Different tissue types with different attenuation will have different Hounsfield values, with distilled water being zero.…”

Laparoskopik Adrenalektomi

“…Malign kitlelerin tespitinde üç fazlı bilgisayarlı tomografi, kimyasal şift magnetik rezonans görüntüleme ve pozitron emisyon tomografi yardımcı olur (7). Adrenokortikal kanser olgularında, özellikle büyük kitlelerde, dokunun yumuşak ve frajil olması ve laparoskopi sırasında basınç altında çalışılmasına bağlı geliştiği düşünü-len postoperatif erken dönemde sistemik metastazlar ve lokal nükslerin arttığını bildiren yayınların varlığı, bu vakalarda açık cerrahiyi tercih sebebi yapmaktadır (8)(9)(10). Bununla birlikte küçük kitlelerde benzer onkolojik sonuç bildiren çalış-malar da mevcuttur (11,12).…”