Contrast enhancement of small hepatocellular carcinoma: Usefulness of three successive early image acquisitions during multiphase dynamic MR imaging

OBJECTIVE. The purpose of this study was to document the usefulness of early triphasic image acquisition during gadolinium-enhanced multiphase dynamic MR imaging for the detection of contrast enhancement in small hepatocellular carcinoma. SUBJECTS AND METHODS. Dynamic MR imaging was performed in 332 patients at 1.5 T using a T1-weighted fast low-angle shot sequence (TR range/TE, 113-130/4.1; flip angle, 80°). With the start of bolus injection of gadolinium dimeglumine (0.1 mmol/kg) into the antecubital vein, three sets of contrast-enhanced images of the entire liver were obtained serially at 10, 35, and 60 sec. Contrast enhancement of the tumor detected on each phase was evaluated in conjunction with the unenhanced T1- weighted images for 52 patients with small hepatocellular carcinomas up to 2 cm in diameter (n = 79). RESULTS. The first phase images depicted a larger number (n = 57) of contrast enhancement of small hepatocellular carcinoma tumors than the second (n = 44) or third phase images (n = 14). Twenty-six lesions were enhanced only during the first phase, and nine, during the second phase. The detection rate of contrast enhancement in the combination of first and second phases was the same as the overall detection rate for all three phases (70/79, 89%) and significantly higher than those of each phase. CONCLUSION. Early multiple image acquisition is helpful for the assessment of small hepatocellular carcinoma and is enabled by the high detection rate of contrast enhancement regardless of individual variations in the timing of enhancement.