When the contrast effect in the tumor was greater or smaller than the range of intensity variability in the parenchyma, the lesion was defined as hyper- or hypo-enhancement. In cases where the contrast Torin 1 order effect in the tumor was within the range of the intensity variability, the lesion was defined as iso-enhancement. All data were expressed as the mean ± standard deviation (SD), median, or percentage. Continuous variables were analyzed by Student t-test or Mann–Whitney U-test. Categorical variables were analyzed using the Fisher exact test or chi-squared test. The cumulative rates were analyzed by Kaplan–Meier

method, and the multivariate analyses were assessed by Cox regression using the best cut-off value obtained from receiver operating characteristics curves. P-values < 0.05 were considered to be significant. Statistical analysis was performed using the SAS software (version 9.2; SAS Institute, Cary, NC, USA). CEUS was performed in 222 patients with 321 lesions during the study period. However, because follow-up was not performed for 13 patients with 19 lesions, CEUS findings were examined for a total of 209 patients with 302 lesions (Fig. 1). A total of 72 subjects (45 males and 27 females; age 65.0 ± 10.8 years) with 87 PIELs (Tables 1 and 2) met the inclusion and exclusion criteria. The mean lesion diameter was 12.5 mm (SD, 4.2 mm; range

5–26.5). The median observation period was 22.0 months (3.3–53.1). Twenty patients

VX-765 research buy developed HCC lesions during the study period; a single lesion was detected in nine patients, two lesions in two patients, and three or more lesions in nine patients. Diagnosis of HCC was made by CEUS, CT, and MRI in 12, by CT and MRI in four, by CEUS and CT in three, and by CEUS and MRI in one. The mean diameter of HCC at the time of detection/diagnosis was 15.1 ± 4.0 mm (10.0–28.6). The overall cumulative HCC occurrence rates were 7.9% at 1 year, 26.3% at 2 years, and 36.0% at 3 years. A total of 14 patients had developed HCC originating from PIELs, and six patients had HCCs not from PIELs. Although there were three PIELs that showed arterial-phase hyper-enhancement selleck chemicals llc at the time of detection, their diameter and contrast-enhanced appearance remained unchanged, and they did not progress to HCC during the follow-up periods of 22.2, 23.3, and 30.6 months. Univariate analysis showed that the presence of coexistent HCC (P = 0.001) and alpha-fetoprotein (AFP) > 20 ng/mL (P = 0.002) were significant factors at baseline for HCC occurrence. The overall cumulative HCC occurrence rates were significantly higher in patients with coexistent HCC (n = 29; 11.1% at 1 year, 59.9% at 3 years) than those without coexistent HCC (n = 43; 5.7% at 1 year, 17.3% at 3 years; P = 0.001) (Fig. 2), and in patients with AFP > 20 ng/mL (n = 22; 16.3% at 1 year, 68.