Early Enhancement Research Articles

Detectability of hepatocellular carcinoma by gadoxetate disodium‐enhanced hepatic MRI: Tumor‐by‐tumor analysis in explant livers

To investigate the detectability of hepatocellular carcinoma (HCC) on Gd-EOB-enhanced MR images (Gd-EOB-MRI), we performed tumor-by-tumor analysis of pathologically confirmed tumors using explants from cirrhotic patients who had undergone liver transplantation. We studied 11 explanted livers and classified the tumor intensity during the arterial phase (AP) and the hepatobiliary phase (HBP) as low in HBP with early enhancement (EE) in AP (A), as high in HBP with EE in AP (B), as low in HBP without EE in AP (C), as high in HBP without EE in AP (D), and as iso-intense in HBP with EE in AP (E). The diagnostic criteria for HCC were (i) pattern A and C, (ii) pattern A and E, (iii) pattern C and E, and (iv) patterns A, C, and E. Of the 71 HCCs, 22 were not detected at MRI; of these, 9 were moderately differentiated and 13 were well-differentiated HCCs. The sensitivity of Gd-EOB-MRI for diagnostic criteria 1, 2, 3, and 4 was 63.4%, 52.1%, 22.5%, and 69.0%. The maximum sensitivity of Gd-EOB-MRI for HCC was only 69.0% even when diagnostic criteria that included all previously reported HCC patterns were adopted.

Dynamic magnetic resonance imaging of the metacarpophalangeal joints in rheumatoid arthritis, early unclassified polyarthritis, and healthy controls

Objective. To introduce dynamic magnetic resonance imaging (MRI) as an indicator of inflammatory activity in the metacarpophalangeal (MCP) joints of patients with rheumatoid arthritis (RA) or early unclassified polyarthritis, and to compare the results with a healthy control group. Materials and Methods. We examined 42 RA and 23 early unclassified polyarthritis patients, and 12 healthy controls in a cross-sectional study. Dynamic MRI (repeated FLASH-MR images after injection of a contrast agent) was performed through the 2nd to the 5th MCP joint. Two methods for identification of the enhancing synovial membrane were compared: 1) outlining of enhancing synovial membrane on subtraction images and 2) automated recognition by principal component analysis (PCA). The early enhancement (EE) rate was calculated on the basis of the first method. Results. Method 1) and 2) were closely associated (P<0.00001). From the healthy control group, an upper limit (mean+2SD) of normal enhancement was established for the 2nd to 5th MCP joints, which served to identify abnormal EE rates in the corresponding joints of patients. The patients had higher EE rates in the 2nd to 5th MCP joints than had the healthy controls (P<0.01). There were no significant differences between the two patient groups (P>0.09). Conclusion. PCA seems to be a promising method for automated identification of enhancing tissue. EE rates of the finger joints may be useful in the assessment of the inflammatory activity in the joints of patients with RA and early unclassified polyarthritis and may reflect other aspects of disease activity than clinical evaluation.