Normalized Parameters of Dynamic Contrast-Enhanced Perfusion MRI and DWI-ADC for Differentiation between Posttreatment Changes and Recurrence in Head and Neck Cancer
Akira Baba, Ryo Kurokawa, E. Rawie, Mariko Kurokawa, Yoshiaki Ota, Ashok Srinivasan
Abstract
<h3>BACKGROUND AND PURPOSE:</h3> Differentiating recurrence from benign posttreatment changes has clinical importance in the imaging follow-up of head and neck cancer. This study aimed to investigate the utility of normalized dynamic contrast-enhanced MR imaging and ADC for their differentiation. <h3>MATERIALS AND METHODS:</h3> This study included 51 patients with a history of head and neck cancer who underwent follow-up dynamic contrast-enhanced MR imaging with DWI-ADC, of whom 25 had recurrences and 26 had benign posttreatment changes. Quantitative and semiquantitative dynamic contrast-enhanced MR imaging parameters and ADC of the ROI and reference region were analyzed. Normalized dynamic contrast-enhanced MR imaging parameters and normalized DWI-ADC parameters were calculated by dividing the ROI by the reference region. <h3>RESULTS:</h3> Normalized plasma volume, volume transfer constant between extravascular extracellular space and blood plasma per minute (<i>K</i><sup>trans</sup>), area under the curve, and wash-in were significantly higher in patients with recurrence than in those with benign posttreatment change (<i>P</i> = .003 to <.001). The normalized mean ADC was significantly lower in patients with recurrence than in those with benign posttreatment change (<i>P </i>< .001). The area under the receiver operating characteristic curve of the combination of normalized dynamic contrast-enhanced MR imaging parameters with significance (normalized plasma volume, normalized extravascular extracellular space volume per unit tissue volume, normalized <i>K</i><sup>trans</sup>, normalized area under the curve, and normalized wash-in) and normalized mean ADC was 0.97 (95% CI, 0.93–1). <h3>CONCLUSIONS:</h3> Normalized dynamic contrast-enhanced MR imaging parameters, normalized mean ADC, and their combination were effective in differentiating recurrence and benign posttreatment changes in head and neck cancer.