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摘要
OBJECTIVE. The purpose of this article is to evaluate single-source dual-energy CT (DECT) for distinguishing benign and indeterminate adrenal nodules, with attention to the effects of phase of IV contrast enhancement. MATERIALS AND METHODS. A retrospective review revealed 273 contrast-enhanced abdominal DECT examinations from November 2009 through March 2012. Fifty adrenal nodules 0.8 cm or larger were identified in 41 patients (22 women and 19 men; average age, 66 years; age range, 36-88 years). CT postprocessing and measurements were independently performed by two radiologists (readers 1 and 2) for each nodule, as follows: attenuation (in Hounsfield units) on true unenhanced images; contrast-enhanced attenuation (in Hounsfield units) on monochromatic spectral images at 40, 75, and 140 keV; and contrast-enhanced material density (in milligrams per milliliter) on virtual unenhanced images. Nodules were classified as benign (< 10 HU) and indeterminate (>= 10 HU) according to true unenhanced images. RESULTS. Interreader agreement regarding benign and indeterminate nodules was high (kappa = 0.92; 95% CI, 0.8-1.0). At 140 keV, the attenuation of benign nodules was significantly lower (reader 1, 7.0 +/- 12.5 HU; reader 2, 7.8 +/- 9.2 HU) than that of indeterminate nodules (reader 1, 15.7 +/- 20.5 HU [p = 0.004]; reader 2, 17.5 +/- 13.4 HU [p < 0.0001]). On virtual unenhanced images, benign nodules had significantly lower material density (reader 1, 992.4 +/- 9.9 mg/mL; reader 2, 992.7 +/- 9.6 mg/mL) than did indeterminate nodules (reader 1, 1001.1 +/- 20.5 mg/mL [p < 0.038]; reader 2, 1007.6 +/- 13.4 mg/mL [p < 0.0001]). CONCLUSION. DECT tools can mathematically subtract iodine or minimize its effects in high-energy reconstructions, approximating unenhanced imaging and potentially reducing the need for additional studies to triage adrenal nodules detected on contrast-enhanced DECT examinations.
- 出版日期2014-8
