Author of 1 Presentation
SS 8.2 - Value of high-resolution diffusion-weighted imaging for the evaluation of extramural tumour invasion in primary rectal cancer (ID 621)
Abstract
Purpose
To determine the added value of diffusion-weighted imaging (DWI) to T2-weighted imaging (T2WI) for the evaluation of extramural tumor invasion (EMTI) in patients with primary rectal cancer.
Material and methods
Seventy-eight patients (51 men, 27 women; mean age, 67 years; range, 49-87 years) who had undergone 3.0-T MRI including high-resolution DWI (2x2x2 mm3 isovoxel, b=0, 1000 s/mm2) and subsequent surgery were included in this retrospective study. To evaluate the added value of DWI, two blinded radiologists independently read the T2WI first and 4 weeks later the combined (T2WI+ DWI) set. They recorded their confidence level using a 5-point scale (1, definitely negative; 2, probably negative; 3, equivocal; 4, probably positive; and 5, definitely EMTI positive). The diagnostic accuracy for each reviewer was calculated by ROC curve analysis. The added value of DWI to T2WI for EMTI evaluation was determined by pair-wise comparison of the ROC curves. The histopathological results served as the reference standard for EMTI.
Results
The study population consisted of T1 (n=9), T2 (n=25), T3 (n=38) and T4 (n=6) patients and sub-divided into positive EMTI (n=44) and negative EMTI (n=34) groups. The AUC was not significantly increased after adding DWI to T2WI (for reader 1, 0.868 (95% CI, 0.772 – 0.934) to 0.856 (95% CI, 0.758 – 0.925), P=0.5618; for reader 2, 0.848 (95% CI, 0.748 – 0.919) to 0.865 (95% CI, 0.769 – 0.932), P=0.4539).
Conclusion
Adding DWI to T2WI showed no additional diagnostic value for the evaluation of EMTI in patients with primary rectal cancer.