Role of diffusion Weighted MRI in the Differentiation between Post treatment Changes and Residual/Recurrent Head and Neck carcinoma

Abstract

Combined qualitative and quantitative analysis of DWI is a useful non-invasive technique to differentiate recurrent head and neck malignancies from post-treatment changes using a threshold ADC value Quantitative analysis of diffusion metrics can help in distinguishing benign from malignant lesions, predicting tumor response to treatment based on pretreatment characteristics, monitoring and assessing the response to treatment as therapy progresses, and surveilling areas of prior treatment to detect post-treatment and recurrent malignant tissue Overall, malignant lesions tend to have lower ADC values compared to benign lesions. In addition, this study showed that mean ADC of recurrent tumors (mean ADC 0.93±0.17 ×10-3 mm2/s) were significantly lower than those of post treatment changes (mean ADC 1.36±0.36 ×10-3 mm2/s) (p-value = P<0.0001, significant if P≤0.05). An ADC cutoff point of 1.2X10-3 mm2/s was best for differentiating benign or inflammatory lesions from malignant recurrence; it provided 88.3% sensitivity and 71.4% specificity.