Efficiency of Non-Contrast-Enhanced Liver Imaging Sequences Added to Initial Rectal MRI in Rectal Cancer Patients.

Gene-Hyuk Kwon,Seong Su Hwang,Ji Woong Kim,Kyung Ah Kim,Sun Young Choi,Soo Youn Park,Hyun A Kim,Zhuoli Zhang

doi:10.1371/journal.pone.0137320

Gene-Hyuk Kwon, Seong Su Hwang + Show 6 more

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https://doi.org/10.1371/journal.pone.0137320

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Abstract

PurposeThe purpose of this study was to estimate the value of addition of liver imaging to initial rectal magnetic resonance imaging (MRI) for detection of liver metastasis and evaluate imaging predictors of a high risk of liver metastasis on rectal MRI.MethodsWe enrolled 144 patients who from October 2010 to May 2013 underwent rectal MRI with T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) (b values = 50, 500, and 900 s/mm2) of the liver and abdominopelvic computed tomography (APCT) for the initial staging of rectal cancer. Two reviewers scored the possibility of liver metastasis on different sets of liver images (T2WI, DWI, and combined T2WI and DWI) and APCT and reached a conclusion by consensus for different analytic results. Imaging features from rectal MRI were also analyzed. The diagnostic performances of CT and an additional liver scan to detect liver metastasis were compared. Multivariate logistic regression to determine independent predictors of liver metastasis among rectal MRI features and tumor markers was performed. This retrospective study was approved by the Institutional Review Board, and the requirement for informed consent was waived.ResultsAll sets of liver images were more effective than APCT for detecting liver metastasis, and DWI was the most effective. Perivascular stranding and anal sphincter invasion were statistically significant for liver metastasis (p = 0.0077 and p = 0.0471), while extramural vascular invasion based on MRI (mrEMVI) was marginally significant (p = 0.0534).ConclusionThe addition of non-contrast-enhanced liver imaging, particularly DWI, to initial rectal MRI in rectal cancer patients could facilitate detection of liver metastasis without APCT. Perivascular stranding, anal sphincter invasion, and mrEMVI detected on rectal MRI were important imaging predictors of liver metastasis.

Highlights

Rectal cancer accounts for about one-third of all colorectal cancers and is a common malignancy and the fourth leading cause of cancer death worldwide [1]
All sets of liver images were more effective than Abdominopelvic computed tomography (CT) (APCT) for detecting liver metastasis, and diffusion-weighted imaging (DWI) was the most effective
Perivascular stranding and anal sphincter invasion were statistically significant for liver metastasis (p = 0.0077 and p = 0.0471), while extramural vascular invasion based on Magnetic resonance imaging (MRI) was marginally significant (p = 0.0534)

Summary

Introduction

Rectal cancer accounts for about one-third of all colorectal cancers and is a common malignancy and the fourth leading cause of cancer death worldwide [1]. Abdominopelvic CT (APCT) is typically obtained to search for metastasis in the abdominal organs or lymph nodes, and chest CT is performed to identify lung metastasis. While this suite of imaging procedures may be helpful for the accurate tumor staging of rectal cancer, it results in high examination fees and radiation exposure. If adding liver imaging to routine rectal MRI could allow for effective detection of liver metastasis, APCT could be removed from the protocol, and both the number of overall procedures and radiation exposure could be reduced.

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