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We have read the letter from Drs Lacout and Marcy regarding our recent Radiology article ( 1 ) and hereby provide our reply. We investigated all nodules that underwent US-guided FNAB, regardless of size and gray-scale US features, not just nodules with at least one suspicious gray-scale feature. Suspicious gray-scale US features that were widely used were determined on the basis of all the nodules studied, not a subgroup. Suspicious US features were investigated for all nodules to evaluate the association between the prediction of malignancy and US features. If the study were performed in a subgroup, the power Doppler US features would not be factors for differentiating benign and malignancy; they would simply be predominant features in the subgroups. The power Doppler features were investigated in the hypoechoic subgroup in our study, but the diagnostic performance was also low. In terms of the qualitative analysis, it should be performed after intranodular vascularity is validated as a factor that predicts malignancy. Moreover, there were no objective criteria for “the rich intralesional vascularity with anarchical structure and winding vessel” or “nodules Renal Oncocytoma: Misleading Diagnosis of Benignancy by Using Angular Interface Sign at MR Imaging

Lung nodule volumetry is used for nodule diagnosis, as well as for monitoring tumor response to therapy. Volume measurement precision and accuracy depend on a number of factors, including image-acquisition and reconstruction parameters, nodule characteristics, and the performance of algorithms for nodule segmentation and volume estimation. The purpose of this article is to provide a review of published studies relevant to the computed tomographic (CT) volumetric analysis of lung nodules. A number of underexamined areas of research regarding volumetric accuracy are identified, including the measurement of nonsolid nodules, the effects of pitch and section overlap, and the effect of respiratory motion. The need for public databases of phantom scans, as well as of clinical data, is discussed. The review points to the need for continued research to examine volumetric accuracy as a function of a multitude of interrelated variables involved in the assessment of lung nodules. Understanding and quantifying the sources of volumetric measurement error in the assessment of lung nodules with CT would be a first step toward the development of methods to minimize that error through system improvements and to correctly account for any remaining error.