Objective:

To explore the value of histogram analysis of baseline CT portal images before treatment in predicting the response of patients with colorectal liver metastases (CRLMs) to neoadjuvant chemotherapy.

Methods:

Thirty-four patients (a total of 1

32 lesions) diagnosed with CRLM were retrospectively enrolled and underwent contrast-enhanced CT before and after neoadjuvant chemotherapy (FOLFOX

FOLFIRI or CapeOX ). All patients underwent pre-treatment CT baseline scan withinfour weeks for primary tumor assessment and a second CT scan in 2 to 3 months

for response evaluation. Histogram of CT portal images of patients with CRLM was analyzed and response was mainly assessed using Response Evaluation Criteria in Solid Tumors (RECIST) Version 1.1. The texture parameters of the metastatic tumor were analyzed statistically to find the differences in baseline CT histogram parameters between responding group and non-responding group before and after treatment. The receiver operating characteristic (ROC) curves were depicted to characterize each parameter value in evaluating the treatment outcomes. The optimal cutoff value (obtained according to the maximal Youden index = sensitivity + specificity-1)

the corresponding sensitivity

specificity

positive predictive value (PPV)

negative predictive value (NPV) and accuracy were calculated. Regions of interests (ROIs) were manually drawn on the largest cross-sectional area of the primary lesions by two radiologists in consensus.

Results:

Twenty-one responding and 13 non-responding patients were evaluated. The values of mean

variance

skewness and percentile (10th

50th

90th

99th) in responding group were much lower than those in non-responding group (

P

0.05). The kurtosis and 1st percentile values between the two groups had no significant difference (

P

=0.769

P

=0.06

respectively). The optimal cutoff value for the accurate identification of responding patients was 167 for 90th percentile (74.42% sensitivity

95.65% specificity

96.97% PPV

66.67% NPV

81.82% accuracy

and 0.854 area under curve

respectively).

Conclusion:

CT histogram analysis of baseline CT portal images before treatment can help to predict the response of patients with CRLM after neoadjuva

nt chemotherapy.