title: Characterization of Small Focal Renal Lesions: Diagnostic Accuracy with Single-Phase Contrast-enhanced Dual-Energy CT with Material Attenuation Analysis Compared with Conventional Attenuation Measurements.
abstract: Purpose To determine whether single-phase contrast material-enhanced dual-energy material attenuation analysis improves the characterization of small (1-4 cm) renal lesions compared with conventional attenuation measurements by using histopathologic analysis and follow-up imaging as the clinical reference standards. Materials and Methods In this retrospective, HIPAA-compliant, institutional review board-approved study, 136 consecutive patients (95 men and 41 women; mean age, 54 years) with 144 renal lesions (111 benign, 33 malignant) measuring 1-4 cm underwent single-energy unenhanced and contrast-enhanced dual-energy computed tomography (CT) of the abdomen. For each renal lesion, attenuation measurements were obtained; attenuation change of greater than or equal to 15 HU was considered evidence of enhancement. Dual-energy attenuation measurements were also obtained by using iodine-water, water-iodine, calcium-water, and water-calcium material basis pairs. Mean lesion attenuation values and material densities were compared between benign and malignant renal lesions by using the two-sample t test. Diagnostic accuracy of attenuation measurements and dual-energy material densities was assessed and validated by using 10-fold cross-validation to limit the effect of optimistic bias. Results By using cross-validated optimal thresholds at 100% sensitivity, iodine-water material attenuation images significantly improved specificity for differentiating between benign and malignant renal lesions compared with conventional enhancement measurements (93% [103 of 111]; 95% confidence interval: 86%, 97%; vs 81% [90 of 111]; 95% confidence interval: 73%, 88%) (P = .02). Sensitivity with iodine-water and calcium-water material attenuation images was also higher than that with conventional enhancement measurements, although the difference was not statistically significant. Conclusion Contrast-enhanced dual-energy CT with material attenuation analysis improves specificity for characterization of small (1-4 cm) renal lesions compared with conventional attenuation measurements.©RSNA, 2017 Online supplemental material is available for this article.
authors.affiliation: From the Department of Radiology (D.M., D.D., B.P., R.T.G., A.M., R.C.N.) and Carl E. Ravin Advanced Imaging Laboratories (K.R.C.), Duke University Medical Center, Box 3808 Erwin Rd, Durham, NC 27710.
authors.forename: Daniele
authors.initials: D
authors.lastname: Marin
authors.affiliation: From the Department of Radiology (D.M., D.D., B.P., R.T.G., A.M., R.C.N.) and Carl E. Ravin Advanced Imaging Laboratories (K.R.C.), Duke University Medical Center, Box 3808 Erwin Rd, Durham, NC 27710.
authors.forename: Drew
authors.initials: D
authors.lastname: Davis
authors.affiliation: From the Department of Radiology (D.M., D.D., B.P., R.T.G., A.M., R.C.N.) and Carl E. Ravin Advanced Imaging Laboratories (K.R.C.), Duke University Medical Center, Box 3808 Erwin Rd, Durham, NC 27710.
authors.forename: Kingshuk
authors.initials: K
authors.lastname: Roy Choudhury
authors.affiliation: From the Department of Radiology (D.M., D.D., B.P., R.T.G., A.M., R.C.N.) and Carl E. Ravin Advanced Imaging Laboratories (K.R.C.), Duke University Medical Center, Box 3808 Erwin Rd, Durham, NC 27710.
authors.forename: Bhavik
authors.initials: B
authors.lastname: Patel
authors.affiliation: From the Department of Radiology (D.M., D.D., B.P., R.T.G., A.M., R.C.N.) and Carl E. Ravin Advanced Imaging Laboratories (K.R.C.), Duke University Medical Center, Box 3808 Erwin Rd, Durham, NC 27710.
authors.forename: Rajan T
authors.initials: RT
authors.lastname: Gupta
authors.affiliation: From the Department of Radiology (D.M., D.D., B.P., R.T.G., A.M., R.C.N.) and Carl E. Ravin Advanced Imaging Laboratories (K.R.C.), Duke University Medical Center, Box 3808 Erwin Rd, Durham, NC 27710.
authors.forename: Achille
authors.initials: A
authors.lastname: Mileto
authors.affiliation: From the Department of Radiology (D.M., D.D., B.P., R.T.G., A.M., R.C.N.) and Carl E. Ravin Advanced Imaging Laboratories (K.R.C.), Duke University Medical Center, Box 3808 Erwin Rd, Durham, NC 27710.
authors.forename: Rendon C
authors.initials: RC
authors.lastname: Nelson
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*