Objective  To evaluate the value of contrast-enhanced ultrasound (CEUS) in the diagnosis of subcapsular small liver cancer.

  Methods  Fifty-one patients diagnosed with subcapsular liver cancer by ultrasound or other imaging between January 2017 and July 2019 were enrolled. The manifestations of conventional ultrasound and contrast-enhanced ultrasonography were analyzed, and the characteristics, summarized.

  Results  There were a total of 53 lesions, all of which were confirmed on the basis of surgical findings, clinical manifestations, or imaging findings. All lesions were located under the liver capsule. Forty-five lesions were located close to the liver capsule, whereas 8 lesions were located within 10 mm from the liver capsule. Of the subcapsular lesions, 90.6% (48/53) were isoechoic and slightly higher or lower echoic, and 94.3% (50/53) had unclear boundaries. CEUS revealed rapid arterial enhancement in 48 of 53 lesions and synchronous enhancement in 5 lesions. In the portal phase, 38 lesions (71.7%) presented hypoechoic changes, and 15 lesions presented isoechoic changes. In the delayed phase, 50 lesions (94.3%) presented hypoechoic changes, and 3 lesions presented isoechoic changes. Among the 53 lesions, the "fast in and fast out" type was found in 38 cases (71.7%) and the "fast in and slow out" type, in 12 cases (22.6%). There were also 3 cases (5.7%) of "fast in and no out" type. Conventional ultrasound revealed 15 lesions, with a detection rate of 28.3% (15/53), and contrast-enhanced ultrasound revealed 53 lesions, with a detection rate of 100% (53/53). The difference between the two methods was statistically significant (P < 0.01).

  Conclusion  Contrast-enhanced ultrasound has a high detection rate for subcapsular small liver cancer and has a significant clinical value.