Published online Jun 7, 2019. doi: 10.3748/wjg.v25.i21.2636
Peer-review started: February 22, 2019
First decision: March 27, 2019
Revised: April 30, 2019
Accepted: May 8, 2019
Article in press: May 8, 2019
Published online: June 7, 2019
Processing time: 104 Days and 9.5 Hours
Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. Higher pathologic stage of HCC has higher risk of recurrence and shorter survival. However, accurate prediction of pathologic stage from current pre-treatment imaging features is still difficult.
Modern magnetic resonance imaging (MRI) techniques using tissue-specific contrast agents provide many imaging features. We hypothesize that these imaging features may help to determine or predict pathologic stage of HCC.
To analyze the relationship between imaging features and the pathologic stage of HCC.
There were 114 patients [75 with pathologic stage T1 (pT1) HCC and 39 with pathologic stage T2 (pT2) HCC] in this study. We reviewed each patient’s imaging features on preoperative gadoxetic acid-enhanced (EOB) MRI. These included: hyperintensity in unenhanced T2-weighted images, hypointensity in unenhanced T1-weighted images, arterial enhancement, corona enhancement, washout appearance, capsular appearance, hypointensity in the tumor tissue during the hepatobiliary (HB) phase, peritumoral hypointensity in the HB phase, hypointense rim in the HB phase, intratumoral fat, hyperintensity on diffusion-weighted imaging, hypointensity on apparent diffusion coefficient map, mosaic appearance, nodule-in-nodule appearance, and the margin. All of these patients underwent surgery and sections of their tumor specimens were analyzed microscopically by an experienced pathologist. Univariate and multivariate analyses were performed to identify predictors of microvascular invasion or satellite nodules.
We found that large tumor size (≥ 2.3 cm) and two MR findings, i.e., corona enhancement [odds ratio = 2.67; 95% confidence interval: 1.101-6.480) and peritumoral hypointensity in HB phase images (odds ratio = 2.203; 95% confidence interval: 0.961-5.049) were associated with high risk of pT2 HCC. The positive likelihood ratio was 6.25 (95% confidence interval: 1.788-21.845) and sensitivity of EOB-MRI for detecting pT2 HCC was 86.2% when two or three of these MRI features were present. Small tumor size and hypointense rim in the HB phase were regarded as benign features. Small HCCs with hypointense rim but not associated with aggressive features were mostly pT1 lesions (specificity, 100%).
Imaging features on EOB-MRI could potentially be used to predict the pathologic stage of solitary HCC as pT1 or pT2.
Imaging biomarkers of HCC are not yet well established. This study further identified imaging features of EOB-MRI that can be used to predict pathologic stage. This should be further validated in prospective studies. Research should be carried out to determine whether these MRI biomarkers help improve the clinical outcome of patients with HCC.