The stratification of severity of acute radiation proctopathy after radiotherapy for cervical carcinoma using diffusion-weighted MRI.

OBJECTIVE

To determine whether diffusion-weighted imaging (DWI) can be used for quantitatively evaluating severity of acute radiation proctopathy after radiotherapy for cervical carcinoma.

MATERIALS AND METHODS

One hundred and twenty-four patients with cervical carcinoma underwent MR examination including DWI before and after radiotherapy. Acute radiation proctopathy was classified into three groups (grade 0, grade I-II and grade III-IV) according to Toxicity Criteria of the Radiation Therapy Oncology Group (RTOG). The pretreatment ADC (ADC), ADC after treatment (ADC) and ADC change (ΔADC) were compared among three groups. In addition, acute radiation proctopathy was classified into good-prognosis group and poor-prognosis group. ADC, ADC and ΔADC were compared between two groups. For DWI parameter that had significant difference, discriminatory capability of the parameter was determined using receiver operating characteristics (ROC) analysis.

RESULTS

ADC and ΔADC were higher in grade I-II group than in grade 0 group (p<0.05), yielding a sensitivity of 79.3% and specificity of 69.4% for ADC, and 85.1%, 72.3% for ΔADC for discrimination between two groups. ADC and ΔADC were higher in grade III-IV group than in grade I-II group (p<0.05), yielding a sensitivity of 80.3% and specificity of 72.5% for ADC, and 84.1%, 74.5% for ΔADC for discrimination between two groups. ADC and ΔADC were higher in poor-prognosis group than in good-prognosis group (p<0.05), yielding a sensitivity of 79.5% and specificity of 73.4% for ADC, and 87.2%, 78.3% for ΔADC for discrimination between two groups.

CONCLUSION

Diffusion-weighted MRI can be used for quantitative stratification of severity of acute radiation proctopathy, which serves as an important basis for appropriate timely adjustment of radiotherapy for cervical carcinoma in order to maximally reduce the radiation injury of rectum.