Purpose: To compare the diagnostic accuracy of iodine quantification and standard enhancement measurements in distinguishing enhancing from nonenhancing renal masses.
Materials and methods: The Institutional Review Board approved this retrospective study conducted from data found in institutional patient databases and archives. Seventy-two renal masses were characterised as enhancing or nonenhancing using standard enhancement measurements (in HU) and iodine quantification (in mg/ml). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of standard enhancement measurements and iodine quantification were calculated from χ (2) tests of contingency with histopathology or imaging follow-up as the reference standard. Difference in accuracy was assessed by means of McNemar analysis.
Results: Sensitivity, specificity, PPV, NPV and diagnostic accuracy for standard enhancement measurements and iodine quantification were 77.7 %, 100 %, 100 %, 81.8 %, 89 % and 100 %, 94.4 %, 94.7, 100 % and 97 %, respectively. The McNemar analysis showed that the accuracy of iodine quantification was significantly better (P < 0.001) than that of standard enhancement measurements.
Conclusion: Compared with standard enhancement measurements, whole-tumour iodine quantification is more accurate in distinguishing enhancing from nonenhancing renal masses.
Key points: • Enhancement of renal lesions is important when differentiating benign from malignant tumours. • Dual-energy CT offers measurement of iodine uptake rather than mere enhancement values. • Whole-tumour iodine quantification seems more accurate than standard CT enhancement measurements.