Pretreatment diffusion-weighted and dynamic contrast-enhanced MRI for prediction of local treatment response in squamous cell carcinomas of the head and neck

Abstract

Objective: The objective of our study was to predict response to chemoradiation therapy in patients with head and neck squamous cell carcinoma (HNSCC) by combined use of diffusion-weighted imaging (DWI) and high-spatial-resolution, high-temporal-resolution dynamic contrast-enhanced MRI (DCE-MRI) parameters from primary tumors and metastatic nodes.

Subjects and methods: Thirty-two patients underwent pretreatment DWI and DCE-MRI using a modified radial imaging sequence. Postprocessing of data included motion-correction algorithms to reduce motion artifacts. The median apparent diffusion coefficient (ADC), volume transfer constant (K(trans)), extracellular extravascular volume fraction (v(e)), and plasma volume fraction (v(p)) were computed from primary tumors and nodal masses. The quality of the DCE-MRI maps was estimated using a threshold median chi-square value of 0.10 or less. Multivariate logistic regression and receiver operating characteristic curve analyses were used to determine the best model to discriminate responders from nonresponders.

Results: Acceptable χ(2) values were observed from 84% of primary tumors and 100% of nodal masses. Five patients with unsatisfactory DCE-MRI data were excluded and DCE-MRI data for three patients who died of unrelated causes were censored from analysis. The median follow-up for the remaining patients (n = 24) was 23.72 months. When ADC and DCE-MRI parameters (K(trans), v(e), v(p)) from both primary tumors and nodal masses were incorporated into multivariate logistic regression analyses, a considerably higher discriminative accuracy (area under the curve [AUC] = 0.85) with a sensitivity of 81.3% and specificity of 75% was observed in differentiating responders (n = 16) from nonresponders (n = 8).

Conclusion: The combined use of DWI and DCE-MRI parameters from both primary tumors and nodal masses may aid in prediction of response to chemoradiation therapy in patients with HNSCC.

Fig. 1

Images obtained before chemoradiation therapy in 61-year-old man with head and neck squamous cell carcinoma that are representative of patients in responder group. A, Axial T2-weighted image shows heterogeneous hyperintense primary tumor (green arrow) and nodal mass (white arrow) at level IIa of neck. B, Masses shown in A exhibit heterogeneous enhancement on contrast-enhanced T1-weighted image. C–F, Coregistered and corresponding apparent diffusion coefficient map (C) and color-coded dynamic contrast-enhanced MRI–derived volume transfer constant (K^trans) (D), extracellular extravascular volume fraction (v_e) (E), and plasma volume fraction (v_p) (F) maps are shown.

Fig. 2

Images obtained before chemoradiation therapy in 64-year-old man with head and neck squamous cell carcinoma that are representative of patients in nonresponder group. A, Axial T2-weighted image shows heterogeneous hyperintense primary tumor (green arrow) and nodal mass (white arrow) at levels II and III of neck. B, Masses shown in A exhibit heterogeneous enhancement on contrast-enhanced T1-weighted image. C–F, Coregistered and corresponding apparent diffusion coefficient map (C) and color-coded dynamic contrast-enhanced MRI–derived volume transfer constant (K^trans) (D), extracellular extravascular volume fraction (v_e) (E), and plasma volume fraction (v_p) (F) maps are shown.

Fig. 3

Bar graphs show values obtained from primary tumors of responders and of partial responders and nonresponders. Bars represent mean values and error bars represent standard errors. A–D, Distributions of apparent diffusion coefficient (ADC) (A), volume transfer constant (K^trans) (B), extracellular extravascular volume fraction (v_e) (C), and plasma volume fraction (v_p) (D) values are shown.

Fig. 4

Bar graphs show values obtained from metastatic nodal masses of responders and of partial responders and nonresponders. Bars represent mean values and error bars represent standard errors. Asterisk indicates significant difference (p < 0.05) between two groups of patients. A–D, Distributions of apparent diffusion coefficient (ADC) (A), volume transfer constant (K^trans) (B), extracellular extravascular volume fraction (v_e) (C), and plasma volume fraction (v_p) (D) values are shown.

Fig. 5

Receiver operating characteristic (ROC) curves for dynamic contrast-enhanced MRI (DCE-MRI) parameters (volume transfer constant [K^trans], extracellular extravascular volume fraction [v_e], and plasma volume fraction [v_p]) and apparent diffusion coefficient (ADC) values from only primary tumors exhibiting area under ROC curve (AUC) of 0.69 (dotted line) and only nodal masses exhibiting AUC of 0.70 (dashed line). Incorporation of DCE-MRI parameters and ADC values from both primary tumors and nodal masses into multivariate logistic regression model provided best discriminatory accuracy (AUC = 0.85, solid line) in distinguishing between responders and nonresponders with sensitivity of 81.3% and specificity of 75% (p = 0.006).