Ces radiol. 2019, 73(2):87-92 | DOI: 10.55095/CesRadiol2019/013

Application of dual-energy CT to distinguish adrenal adenomas from non-adenomas - first experienceOriginal article

Paulína Szász^1,2, Filip Čtvrtlík^1,2, Petr Kučera^1,2, František Odstrčil^1,3, Kateřina Langová⁴, Radim Kovář^1,3, Hana Študentová⁵, František Hruška⁶, Zbyněk Tüdös^1,2

¹ Radiologická klinika Fakultní nemocnice, Olomouc

² Radiologická klinika Lékařské fakulty Univerzity Palackého, Olomouc

³ Ústav radiologických metod Fakulty zdravotnických věd Univerzity Palackého, Olomouc

⁴ Ústav lékařské biofyziky Univerzity Palackého, Olomouc

⁵ Onkologická klinika Fakultní nemocnice, Olomouc

⁶ Urologická klinika Fakultní nemocnice, Olomouc

Aim: Our aim was to evaluate the role of single-source dual-energy CT (ssDECT) in the differentiation of adrenal adenomas from non-adenomas (i.e., metastases, pheochromocytomas and carcinomas).

Method: The prospective study included 57 patients with a total of 63 adrenal lesions, 37 of which were adenomas and 26 non-adenomas (11 pheochromocytomas, 11 metastases and four adrenocortical carcinomas). All subjects underwent unenhanced dual-energy CT. For all lesions, we measured the mean value of unenhanced density in Hounsfield units (HU) using monochromatic reconstructions on the 40-keV and 140-keV energy levels, the effective atomic number (Z_eff) and the fat content using fat-water material decomposition, and according to the K-value we divided the HU spectral curves into ascending, straight and descending ones. Quantitative parameters were statistically compared by means of a T-test or Mann-Whitney U-test. We compared the frequency of the shapes of the spectral curves with Fischer's exact test. We created Receiver Operating Characteristic (ROC) curves to compare the diagnostic accuracy of individual variables to distinguish adenomas from non-adenomas.

Results: Our results revealed statistically significant differences between adenomas and non-adenomas in mean attenuation using monochromatic energy of 40 keV (17.23 ± 22.68 vs. 52.77 ± 7.47 HU; p < 0.0001) and 140 keV (8.39 ± 9.83 vs. 24.50 ± 5.57 HU; p < 0.0001), in Z_eff values (median 7.70 vs. 7.82; p = 0.0001) and in fat content using material decomposition (-41.13 ± 147.64 vs. -262.07 ± 71.45 mg/ml; p < 0.0001). The shape of the spectral curve in adenomas was descending in 17 cases, straight in 15 cases and ascending in five cases; in non-adenomas the curve was descending in all 26 cases (p = 0.001). In ROC analyses, the best values were reached with a mean density at 40 keV energy level (Area Under Curve 0.927).

Conclusion: Our result revealed statistically significant differences in all the selected parameters. Unenhanced ssDECT seem to have the potential to differentiate adrenal adenomas from non-adenomas.

Keywords: dual-energy CT, adrenal adenoma, pheochromocytoma, adrenocortical carcinoma, metastasis

Grants and funding:

Podpořeno z programového projektu Ministerstva zdravotnictví ČR s reg. č. 17-31847A.

Accepted: March 1, 2019; Published: June 1, 2019  Show citation