Faculty Collaboration Database

Energy-Specific Optimization of Attenuation Thresholds for Low-Energy Virtual Monoenergetic Images in Renal Lesion Evaluation. AJR Am J Roentgenol 2018 May;210(5):W205-W217

Date

03/17/2018

Pubmed ID

29547057

DOI

10.2214/AJR.17.18641

Scopus ID

2-s2.0-85046125775 (requires institutional sign-in at Scopus site)   17 Citations

Abstract

OBJECTIVE: The purpose of this study was to determine in vitro and in vivo the optimal threshold for renal lesion vascularity at low-energy (40-60 keV) virtual monoenergetic imaging.

MATERIALS AND METHODS: A rod simulating unenhanced renal parenchymal attenuation (35 HU) was fitted with a syringe containing water. Three iodinated solutions (0.38, 0.57, and 0.76 mg I/mL) were inserted into another rod that simulated enhanced renal parenchyma (180 HU). Rods were inserted into cylindric phantoms of three different body sizes and scanned with single- and dual-energy MDCT. In addition, 102 patients (32 men, 70 women; mean age, 66.8 ± 12.9 [SD] years) with 112 renal lesions (67 nonvascular, 45 vascular) measuring 1.1-8.9 cm underwent single-energy unenhanced and contrast-enhanced dual-energy CT. Optimal threshold attenuation values that differentiated vascular from nonvascular lesions at 40-60 keV were determined.

RESULTS: Mean optimal threshold values were 30.2 ± 3.6 (standard error), 20.9 ± 1.3, and 16.1 ± 1.0 HU in the phantom, and 35.9 ± 3.6, 25.4 ± 1.8, and 17.8 ± 1.8 HU in the patients at 40, 50, and 60 keV. Sensitivity and specificity for the thresholds did not change significantly between low-energy and 70-keV virtual monoenergetic imaging (sensitivity, 87-98%; specificity, 90-91%). The AUC from 40 to 70 keV was 0.96 (95% CI, 0.93-0.99) to 0.98 (95% CI, 0.95-1.00).

CONCLUSION: Low-energy virtual monoenergetic imaging at energy-specific optimized attenuation thresholds can be used for reliable characterization of renal lesions.

Author List

Patel BN, Farjat A, Schabel C, Duvnjak P, Mileto A, Ramirez-Giraldo JC, Marin D

MESH terms used to index this publication - Major topics in bold

Aged
Contrast Media
Female
Humans
Iodine
Kidney
Kidney Neoplasms
Male
Multidetector Computed Tomography
Phantoms, Imaging
Radiographic Image Interpretation, Computer-Assisted
Sensitivity and Specificity
Signal-To-Noise Ratio