Published online Nov 14, 2013. doi: 10.3748/wjg.v19.i42.7433
Revised: August 16, 2013
Accepted: September 16, 2013
Published online: November 14, 2013
Processing time: 148 Days and 20.3 Hours
AIM: To elucidate the variety of ways early-stage hepatocellular carcinoma (HCC) can appear on magnetic resonance (MR) imaging by analyzing T1-weighted, T2-weighted, and gadolinium-enhanced dynamic studies.
METHODS: Seventy-three patients with well-differentiated HCC (wHCC) or dysplastic nodules were retrospectively identified from medical records, and new histological sections were prepared and reviewed. The tumor nodules were categorized into three groups: dysplastic nodule (DN), wHCC compatible with Edmondson-Steiner grade I HCC (w1-HCC), and wHCC compatible with Edmondson-Steiner grade II HCC (w2-HCC). The signal intensity on pre-contrast MR imaging and the enhancing pattern for each tumor were recorded and compared between the three tumor groups.
RESULTS: Among the 73 patients, 14 were diagnosed as having DN, 40 were diagnosed as having w1-HCC, and 19 were diagnosed as having w2-HCC. Hyperintensity measurements on T2-weighted axial images (T2WI) were statistically significant between DNs and wHCC (P = 0.006) and between DN and w1-HCC (P = 0.02). The other imaging features revealed no significant differences between DN and wHCC or between DN and w1-HCC. Hyperintensity on both T1W out-phase imaging (P = 0.007) and arterial enhancement on dynamic study (P = 0.005) showed statistically significant differences between w1-HCC and w2-HCC. The other imaging features revealed no significant differences between w1-HCC and w2-HCC.
CONCLUSION: In the follow-up for a cirrhotic nodule, increased signal intensity on T2WI may be a sign of malignant transformation. Furthermore, a noted loss of hyperintensity on T1WI and the detection of arterial enhancement might indicate further progression of the histological grade.
Core tip: The aim of this article was to differentiate between early-stage hepatocellular carcinoma (HCC) and dysplastic nodules using conventional magnetic resonance (MR) imaging. We found that conventional MR imaging could provide additional information to differentiate between early-stage HCC and dysplastic nodules in equivocal lesions. During follow-up for a cirrhotic nodules, increased signal intensity on T2-weighted axial images may be a sign of malignant transformation. Loss of hyperintensity on T1WI and the detection of arterial enhancement may indicate further progression of the histological grade.