Sequential Changes in Echogenicity and Conspicuity of Small Hepatocellular Carcinoma on Gray Scale Sonography After Transcatheter Arterial Chemoembolization

Objective. The purpose of this study was to assess sequential changes in the echogenicity and conspicuity of small hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE). Methods. Seventy patients with nodular HCC underwent 3 serial abdominal sonographic examinations before (t0), immediately after (t1), and 2 to 4 days after (t2) TACE. The echogenicity and conspicuity of the HCC nodules were prospectively graded using a 5‐point scale. For all tumors, any changes in the echogenicity and conspicuity scores obtained at t0, t1, and t2 were evaluated. The degree of intratumoral uptake of iodized oil was categorized as compact or noncompact based on unenhanced computed tomographic images. Within each group, the sequential changes in the echogenicity and conspicuity were analyzed. Cross‐sectional comparisons of the echogenicity and conspicuity at each time point between the two groups were also made. Results. Overall, the lesion echogenicity and conspicuity at t1 increased compared with those at t0 ( P < .05). Thereafter, both the echogenicity and conspicuity at t2 decreased compared with those at t1 ( P < .05). There were 41 HCC nodules with compact iodized oil uptake and 29 with noncompact uptake. Significant sequential changes in the echogenicity (increase at t1 followed by decrease at t2) were noted in both groups, but only the compact group showed a significant change in conspicuity. In a cross‐sectional comparison, the compact group showed higher scores for both echogenicity and conspicuity than the noncompact group at both t1 and t2 ( P < .05). Conclusions. The echogenicity and conspicuity of HCC are increased immediately after TACE. These effects are significantly diminished 2 to 4 days after TACE.