Value of dual contrast liver MRI at 3.0 T in differentiating well-differentiated hepatocellular carcinomas from dysplastic nodules: preliminary results of multivariate analysis.
OBJECTIVE
To assess the diagnostic value of dual contrast magnetic resonance imaging (DC-MRI) in the differentiation of well-differentiated hepatocellular carcinomas (WD-HCCs) from dysplastic nodules (DNs) and to determine the significant MRI predictors using univariate and multivariate analyses.


METHODS
Thirty-two WD-HCCs and 33 DNs in 28 patients who underwent liver transplantation with available histopathology as a gold standard were enrolled in this study. All patients underwent DC-MRI using superparamagnetic iron oxide (SPIO) and gadolinium (Gd) agents on a 3 T MRI unit. For all patients, precontrast T1- and T2-weighted (T2W) images as well as post-SPIO T2- and T2*W images were obtained. Then, for dynamic MRI, arterial (AP), portal, and equilibrium images were also obtained. Two radiologists reviewed the MR images for analyzing signal intensity on the all MR sequences in consensus. On AP images, the degree of enhancement was subjectively categorized into 4 groups: no, minimal, moderate, and strong enhancement. For quantitative analysis, relative arterial enhancement ratio was calculated by averaging 3 regions of interest values of each nodule on pre-Gd T1W and AP images. Each variable was initially evaluated using univariate analyses to assess statistically significant MRI findings differentiating HCCs and DNs, then with multivariate logistic regression analysis to find the most predictable MRI findings.


RESULTS
Twenty WD-HCCs showed iso- or high SI on precontrast T2W images, whereas 23 DNs showed low SI (P = 0.003). Most DNs showed low SI on post-SPIO T2W (30/33) and T2*W (25/33) images, whereas HCCs tended to show heterogeneous high or high SI (16/32 and 19/32) (P < 0.012). On post-SPIO and pre-Gd T1W GRE images, 28 WD-HCCs showed iso- or high SI, whereas 24 DNs showed low SI (P < 0.001). On AP images, 20 HCCs revealed more than minimal degree of enhancement, whereas 32 DNs did not show any enhancement (P < 0.001). Mean relative arterial enhancement ratio of HCCs (39.4%) was also significantly larger than that of DNs (15.6%) (P = 0.001). On portal images, WD-HCCs tended to show iso- or high SI (n = 21), whereas DNs showed low SI (n = 29) (P < 0.001). Multivariate analysis revealed that a subjective degree of enhancement on AP images and SI on post-SPIO and pre-Gd T1W GRE images were the 2 variables that independently differentiated WD-HCCs from DNs.


CONCLUSIONS
The use of DC-MRI is helpful in the differentiation of WD HCCs and DNs. More specifically, a subjective degree of enhancement on AP images and SI on post-SPIO and pre-Gd T1W GRE images are the 2 variables that independently differentiate WD-HCCs from DNs.
Yoon
Min A
MA
Department of Radiology, Seoul National University Hospital, Seoul, Korea.
Kim
Se Hyung
SH
Park
Hee Sun
HS
Lee
Dong Ho
DH
Lee
Jae Young
JY
Han
Joon Koo
JK
Choi
Byung Ihn
BI
D000465:Algorithms; D003287:Contrast Media / Q000008:administration & dosage; D003911:Dextrans; D004338:Drug Combinations; D005260:Female; D052203:Ferrosoferric Oxide / Q000008:administration & dosage; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008113:Liver Neoplasms / Q000175:diagnosis*; D058185:Magnetite Nanoparticles; D008297:Male; D008536:Meglumine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D015999:Multivariate Analysis; D009942:Organometallic Compounds / Q000008:administration & dosage; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media; D003911:Dextrans; D004338:Drug Combinations; D058185:Magnetite Nanoparticles; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine; C065507:ferumoxides; D052203:Ferrosoferric Oxide