Therapeutic response assessment using 3D ultrasound in hepatic metastasis from colon cancer: Application of personalized 3D-printed tumor model using CT images

Abstract

Introduction: With technological revolution of three-dimensional (3D) printing in medical field, 3D visualization of anatomy and pathologic condition and creation of 3D-printed physical models became accessible in the diagnostic imaging practices. The purpose of this study was to evaluate the accuracy and reliability of 3D US for response evaluation of hepatic metastasis from colon cancer applying of personalized 3D-printed tumor model using CT images. Methods: Twenty patients with liver metastasis from colorectal cancer who received cytotoxic chemotherapy and underwent CT baseline and after chemotherapy were retrospectively included in this institutional review board-approved study. Personalized 3D-printed ultrasound tumor model were created from CT images. Two radiologists measured the volume of each 3D printing ultrasound tumor model using 3D US. With the tumor volume from CT as a reference standard, we compared the difference between CT volume and US tumor volume. The mean difference and correlation coefficient between each US volume measurement and the CT volume were analyzed. The response evaluation was based on RECIST criteria. Results: There were 10 patients of response group and 10 patients of non-response group. With the tumor volume from CT as a reference standard, tumor volume measurement using 3D US with 3D-printed tumor model showed no statistically significant difference (7.18 ± 5.44 mL in observer 1 and 8.31 ± 6.32 mL in observer 2 vs 7.42 ± 5.76 mL in CT, p>0.05). 3D US provided the high correlation coefficient with the CT volume (r=0.953, observer1

r=0.97, observer2) and with the high inter-observer intraclass correlation (0.978

0.958-0.988). Regarding response assessment, 3D US was in agreement with CT volume in 17 of the 20 patients in observer 1 and 18 of the 20 patients in observer 2 with excellent inter-observer agreement (κ = 0.961). Conclusions: 3D US volumetric measurement applying of personalized 3D-printed tumor model using CT images in hepatic metastasis from colon cancer is accurate and reliable method for the response evaluation in comparison with the tumor volume from CT.