Ultrasound Nakagami Imaging for Noninvasive Evaluation of Vaginal Fibrosis Following Radiotherapy for Gynecologic Malignancies
T Liu*, X Yang, D Bruner, S Tridandapani, H Chen, S Henry, P Rossi, Emory Univ, Atlanta, GAWE-C-BRA-10 Wednesday 10:30:00 AM - 12:30:00 PM Room: Ballroom A
Purpose: Radiation therapy is an important treatment modality for most gynecologic (GYN) malignancies. However, radiation-induced vaginal fibrosis is a debilitating side-effect, affecting 80% of women post pelvic or vaginal radiotherapy. Vaginal fibrosis leads to pain, sexual dysfunction, and poor quality of life. This study's purpose is to develop an ultrasonic tissue characterization technique based on Nakagami parameter imaging to evaluate vaginal fibrosis.
Methods: We investigated the Nakagami imaging concept in a pilot study of 10 patients. All patients were previously diagnosed with endometrial cancer. Four patients who received surgery alone served as the control group. Six patients received surgery plus radiotherapy, and the follow-up time ranged from 12 to 38 months after radiotherapy. Each participant underwent one transvaginal ultrasound study with a 7.5 MHz biplane probe. Three transverse images of the anterior vaginal wall were acquired in a 2 cm step-wise progression from the apex (vaginal cuff) to the introitus (vagina opening). Vaginal wall thickness, Nakagami probability density function (PDF), and Nakagami parameter were calculated to evaluate radiation-induced vaginal injury.
Results: Significant differences in vaginal wall thickness and Nakagami PDF were observed between the post-irradiation and non-irradiated vaginal walls. The average vaginal wall thicknesses were 1.99±0.54 mm for the control group and 4.81±1.55 mm for the post-irradiation group (p<0.01). The average Nakagami PDF values were 2.05±0.13E-3 for the control and 3.54±0.40E-3 for the post-irradiation group (p<0.001). The average Nakagami parameter values were 0.92±0.31 for the control group and 1.21±0.12 for the post-irradiation group (p=0.15). Vaginal fibrosis appears to be associated with a thickened vaginal wall and increased Nakagami parameter.
Conclusions: In this study, we demonstrate the feasibility of using Nakagami imaging to evaluate vaginal fibrosis. Quantitative ultrasound provides a noninvasive, objective means of assessing radiation-induced vaginal injury. This imaging method may be useful as we try to address vaginal toxicities and sexual dysfunction in women after radiotherapy for GYN malignancies.