Assessment of Measurement Repeatability and Reliability With Virtual Touch Tissue Quantification Imaging in Cervical Lymphadenopathy.

Abstract

The purpose of this study was to prospectively assess the repeatability and reliability of 2 measurements of cervical lymphadenopathy using Virtual Touch tissue quantification (VTQ) imaging (Siemens Medical Solutions, Mountain View, CA) and to analyze the factors affecting the reliability of the measurements, including pathologic findings, lesion size and location, and shear wave velocities (SWVs). In this Institutional Review Board-approved prospective study, 92 patients underwent conventional sonography and 2 VTQ measurements by acoustic radiation force impulse imaging in a single session. The repeatability and reliability of the SWV measurement was determined by using an average coefficient of variation (standard deviation/mean) and intraclass correlation coefficient (ICC), respectively. By comparing ICCs with a 95% confidence interval, the effects of pathologic findings, depth, size, SWV, and distance from the carotid artery on reliability were assessed. The mean age of the 92 patients included in the study was 51 years (range, 14-77 years). The average coefficient of variation was 19.4%. The overall reliability of the 2 measurements was excellent (ICC, 0.837), but ICCs were significantly decreased in lymph nodes in a superficial location (<1 cm) and those with a low SWV (<1.8 m/s). No significant effect was found on reliability in relation to pathologic findings, lesion size, or distance from the carotid artery to the lymph nodes. For SWV measurement by VTQ imaging, the repeatability was 19.4%, and reliability was excellent. However, caution is warranted in the use of VTQ imaging for superficial soft cervical lymph nodes, as both a superficial location and a soft composition tend to be characterized by low reliability of SWV findings.