Clinical Performance of Abbreviated Liver MRI for the Follow-Up of Patients With Colorectal Liver Metastases.

Abstract

<b>OBJECTIVE.</b> The objective of our study was to compare an abbreviated liver MRI protocol with a standard liver MRI protocol for the posttreatment follow-up of colorectal metastases in assessing disease presence, segmental involvement, and response to chemotherapy and for surgical planning. <b>MATERIALS AND METHODS.</b> This retrospective single-center study reviewed consecutive chemotherapy-naïve patients with colorectal liver metastases (April 1, 2011-August 31, 2017) who underwent gadoxetate disodium-enhanced MRI on a 1.5-T unit before and 8-12 weeks after chemotherapy. Two radiologists blinded to outcomes independently reviewed images obtained using standard MRI sequences at baseline and after treatment. The standard MRI sequences were the following: axial T1-weighted, axial T2-weighted, axial DWI (b values = 0-750 s/mm²), axial multiphase contrast-enhanced T1-weighted, and axial and coronal hepatobiliary phase (HBP) T1-weighted sequences. The standard sequences obtained at baseline and the abbreviated protocol sequences (i.e., HBP gadoxetate disodium-enhanced T1-weighted and DWI sequences) obtained after treatment were reviewed. For each image set, reviewers assessed disease presence and segmental involvement; in addition, for images obtained after therapy, treatment response according to RECIST 1.1 was recorded. <b>RESULTS.</b> One hundred thirteen patients (73 men and 40 women; mean age, 61.6 years) were evaluated. The total number of metastases showed high agreement between the standard protocol and abbreviated protocol (intraclass correlation coefficient = 0.97). There was good agreement between the protocols for segmental involvement (weighted κ = 0.73-0.85), and the weighted kappa was 0.82 for all segments. Discrepancies in segmental involvement did not alter potential surgical planning. Categorization of RECIST 1.1 treatment response using the abbreviated protocol versus the standard protocol showed excellent agreement (weighted κ = 0.92). <b>CONCLUSION.</b> An abbreviated liver MRI protocol (i.e., HBP gadoxetate disodium-enhanced T1-weighted and DWI sequences) allows assessment after chemotherapy similar to a standard liver MRI protocol. Use of the abbreviated protocol can reduce imaging time without sacrificing diagnostic performance for the follow-up of colorectal liver metastases.