Eur Radiol (2009) 19: 1289–1295 DOI 10.1007/s00330-008-1273-6 UROGENITAL

Dual-energy CT iodine overlay technique for characterization of renal masses as cyst or solid: a phantom feasibility study Abstract The aim of this study was to assess the ability of dual-energy computed tomography (DECT) to classify phantom renal lesions as cysts or enhancing masses. Six cylinders ranging in diameter from 0.5 to 3.0 cm were filled with distilled water or titrated iodinated contrast solutions with CT attenuation values at 120 kVp of 0 Hounsfield units (HU) for a cyst proxy or 10, 20, or 40 HU to represent enhancing masses. These were placed in a 12-cm-diameter renal phantom containing puréed beef mixed with iodinated contrast medium to simulate enhancing renal parenchyma of 100 and 250 HU and submerged within a 28-cm water bath. These combina-tions produced 48 individual phantom renal lesions of differing sizes, internal and parenchymal enhancement (12 cysts and 36 enhancing masses). DECT using 80 and 140 kVp was performed on a dual-source CT scan-ner. Commercial software created a color-encoded overlay indicating the location of iodine within the phantom. The lesions were individually graded as a cyst or enhancing mass by blinded, consensus interpretation of two genitourinary radiologists. Thirty-five of 36 enhancing masses and 10/12 cysts were correctly identified, equat-ing to a sensitivity and specificity o