Small hypervascular enhancing lesions on arterial phase images of multiphase dynamic computed tomography in cirrhotic liver: fate and implications

Our purpose was to determine the significance of small hypervascular enhancing lesions exclusively on the arterial phase images of dynamic computed tomography in cirrhotic liver.

One hundred sixty-nine enhancing lesions (>5 and <30 mm) on the arterial phase images of dynamic computed tomography in 67 patients with cirrhotic liver, not distinguished from background hepatic parenchyma on equilibrium phase images without hypoattenuation density on portal phase images, were subjected to a retrospective assessment in terms of the lesion growth in addition to the location, size, and contour of the lesions, depending on the final diagnoses of the individual lesions.

Twenty-eight (17%) of the 169 enhancing lesions were hepatocellular carcinomas (HCCs). All of the 43 wedge-shaped, subcapsular lesions were benign, and 126 nodular or irregular lesions were subcapsularly (benign, n = 59; HCC, n = 11) or centrally (benign, n = 39; HCC, n = 17) located. Significant differences were found between HCCs and benign lesions in terms of their shape (P = 0.002) and location (P = 0.041), and the positive and negative predictive values of centrally located lesions for diagnosing HCCs were 21% and 85%, respectively. The positive and negative predictive values for the diagnosis of HCC based on the lesion growth were 90% and 93%, respectively.

Because of the low positive predictive value of non-wedge-shaped, centrally located, early enhancing lesions in the diagnosis of HCC, the serial follow-up for examining lesion growth is essential to the correct diagnosis of small arterial hypervascular lesions in cirrhotic liver.