Application of liver acquisition with volume acceleration enhanced sequence in improving the accuracy of reassessing organ-invasive rectal mucinous adenocarcinoma after chemoradiation.

Objectives: To explore the ability of liver acquisition with volume acceleration contrast-enhanced sequence (LAVA-ce) to improve the accuracy of reassessing adjacent organ involvement by rectal mucinous adenocarcinoma (MC) after neoadjuvant therapy (NAT).

Methods: This study retrospectively enrolled twenty-five patients with MC who underwent pre- and post-NAT MRI, were staged as T4b using pre-NAT T weighted imaging, received NAT and underwent radical resection. All MR images were divided into two schemes, T weighted plus diffusion weighted imaging (TD protocol) and plus LAVA-ce (TDL protocol). All patients were scored on a 0-4 scale to reassess organ-invasive mucus components. Postoperative pathology was used to identify the involvement of surrounding organs (ypT4b). The receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to evaluate the consistency of the results with pathology after adding fs-CE sequence.

Results: Among 25 MC patients (15 males and 10 females, aged 21-89 years), 21 were restaged as yT4b after NAT by using TD, with an accuracy of 44.0 % (11/25), which was lower than the accuracy of staging patients with non-mucinous rectal adenocarcinoma (94.1 %, 96/102). The accuracy of MC restaging was improved by using TDL (23/25). The AUC of TDL was 0.857 (95 % CI, 0.660∼0.964), which was higher than that of TD (AUC, 0.611 [95 % CI, 0.397∼0.798]) (P = 0.019).

Conclusion: The LAVA-ce sequence can improve the accuracy of reevaluation and should be included in the MRI protocol for MC patients.