Comparison of Gadoxetic Acid–enhanced MR Imaging versus Four-phase Multi–detector Row Computed Tomography in Assessing Tumor Regression after Radiofrequency Ablation in Subjects with Hepatocellular Carcinomas
Received 6 April 2009; received in revised form 11 November 2009; accepted 16 November 2009. published online 29 January 2010.
Purpose
To assess the diagnostic value of gadoxetic acid–enhanced magnetic resonance (MR) imaging in follow-up of patients with hepatocellular carcinomas (HCCs) who were treated with radiofrequency (RF) ablation and to compare it with that of four-phase multi–detector row computed tomography (CT).
Materials and Methods
From July 2007 to May 2008, 36 patients (43 HCCs) were enrolled who were treated with RF ablation (tumor size, 20–47 mm; mean, 24.5 mm) and underwent gadoxetic acid–enhanced MR imaging and four-phase (precontrast, arterial, portal venous, and equilibrium) multidetector CT for follow-up. Two radiologists independently reviewed these images, and conspicuity of tumor margins and detection of residual or recurrent tumor were assessed on a five-point scale with receiver operating characteristic (ROC) curve analysis. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were evaluated.
Results
The mean conspicuity value of tumor margins was significantly higher on MR imaging than on multidetector CT (P < .001). The degree of differentiation between residual/recurrent tumor and hyperemia was significantly greater on MR imaging (P < .001). The mean area under the ROC curve was significantly higher with MR imaging (P = .015), as were sensitivity, specificity, PPV, NPV, and accuracy of detection rate (mean, 100%, 96.2%, 82.4%, 100%, and 96.7%, respectively, vs 41.7%, 56.8%, 13.5%, 85.7%, and 54.7% for multidetector CT). The interobserver agreement rate for MR imaging was higher (0.919) than for multidetector CT (0.672; P < .05).
Conclusions
Diagnostic accuracy, conspicuity of tumor margins, and detection rate of residual or recurrent tumor were found to be better with gadoxetic acid–enhanced MR imaging than with four-phase multidetector CT.
aDepartment of Radiology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea
bDepartment of Internal Medicine, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea
Address correspondence to J.H.Y., Department of Radiology, University of California San Diego Medical Center-Hillcrest, 408 Dickinson St., San Diego, CA 92103-8226
This work was supported by the 2003 Inje University Research Grant. Support for manuscript editing was received from Bayer Korea. None of the authors have identified a conflict of interest.
ABSTRACT