Adrenal incidentaloma detected on triphasic helical CT: evaluation with modified relative percentage of enhancement washout values.
The aim of this study is to retrospectively assess adrenal incidentalomas detected by triphasic helical CT using modified relative percentage of the enhancement washout (mRPEW) values. 42 adrenal incidentalomas in 35 patients were detected on CT and confirmed by either pathological examination or follow-up CT examination. The mRPEW values were calculated using the attenuation values of the adrenal masses seen on the images from portal phase and delayed phase CT performed 3 min after intravenous injection of contrast material. The diagnostic accuracy of an adenoma was obtained using the mRPEW values. The final diagnosis was an "adenoma" and a "metastasis" in 9 and 33 cases, respectively. The mRPEW values of the adenomas and metastases ranged from 5.8% to 59.4% (26.1+/-15.5%) and from -18.8% to 25% (6.4+/-11.7%), respectively (p<0.05). An mRPEW value of 20% yielded the best accuracy of 88% (37/42) for an adenoma. mRPEW values >25% and < or =5% had a positive predictive value of 100% (3/3) and a negative predictive value of 100% (15/15), respectively. In conclusion, a substantial number of adrenal incidentalomas may be characterized using the mRPEW values from triphasic helical CT without the need for dedicated adrenal CT.
Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. rapark@skku.edu
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Park
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Kim
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Kim
D000236:Adenoma / Q000000981:diagnostic imaging*; D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods* / Q000592:standards