Differentiation of atypical hepatic hemangioma from liver metastases: Diagnostic performance of a novel type of color contrast enhanced ultrasound

Abstract

Background: In clinical practice, the diagnosis is sometimes difficult with contrast-enhanced ultrasound (CEUS) when the case has an atypical perfusion pattern. Color parametric imaging (CPI) is an analysis software for CEUS with better detection of temporal differences in CEUS imaging using arbitrary colors. It measures the differences in arrival time of the contrast agent in lesions so that the perfusion features of atypical hemangioma and colorectal cancer (CRC) liver metastasis can be distinguished.

Aim: To evaluate the role of a novel type of CPI of CEUS in the differential diagnosis of atypical hemangioma from liver metastases in patients with a history of CRC.

Methods: From January 2016 to July 2018, 42 patients including 20 cases of atypical hemangioma and 22 cases of liver metastases from CRC were enrolled. These patients had a mean age of 60.5 ± 9.3 years (range: 39-75 years). All patients received ultrasound, CEUS and CPI examinations. Resident and staff radiologists independently and retrospectively reviewed CEUS and CPI images. Two sets of criteria were assigned: (1) Routine CEUS alone; and (2) CEUS and CPI. The diagnostic sensitivity, specificity, accuracy and receiver operating characteristic (ROC) curve of resident and staff radiologists were analyzed.

Results: The following CPI features were significantly different between liver hemangioma and liver metastases analyzed by staff and resident radiologists: Peripheral nodular enhancement (65%-70.0% vs 4.5%-13.6%, P < 0.001, P = 0.001), mosaic/chaotic enhancement (5%-10% vs 68.2%-63.6%, P < 0.001, P < 0.001) and feeding artery (20% vs 59.1%-54.5%, P = 0.010, P = 0.021). CPI imaging offered significant improvements in detection rates compared with routine CEUS in both resident and staff groups. By resident radiologists, the specificity and accuracy of CEUS+CPI were significantly increased compared with that of CEUS (77.3% vs 45.5%, P = 0.030; 78.6% vs 50.0%, P = 0.006). In addition, the area under the curve (AUC) of CEUS+CPI was significantly higher than that of CEUS (0.803 vs 0.757, P = 0.036). By staff radiologists, accuracy was improved in CEUS+CPI (81.0% vs 54.8%, P = 0.010), whereas no significant differences in specificity and sensitivity were found (P = 0.144, P = 0.112). The AUC of CEUS+CPI was significantly higher than that of CEUS (0.890 vs 0.825, P = 0.013) by staff radiologists.

Conclusion: Compared with routine CEUS, CPI could provide specific information on the hemodynamic features of liver lesions and help to differentiate atypical hemangioma from liver metastases in patients with CRC, even for senior radiologists.

Keywords: Color parametric imaging; Contrast enhanced ultrasound; Liver hemangioma; Liver metastases.

Figure 1

Flow diagram of the study population. CPI: Color parametric imaging; FLL: Focal liver lesions, CEUS: Contrast enhanced ultrasound.

Figure 2

color parametric imaging patterns of liver atypical hemangioma and liver metastases. First line was sketch figures for the four enhancement patterns of color parametric imaging. Second line was representative routine contrast-enhanced ultrasound images corresponding to the four enhancement patterns. Third line was representative color parametric images corresponding to the four patterns. A: Peripheral nodular enhancement; B: Peripheral rim-like with feeding artery (▲); C: Concentric circles enhancement; D: Mosaic enhancement with feeding artery (▲).

Figure 3

Diagnostic confidence of atypical hemangioma and liver metastasis by staff and resident radiologists. The number of 3-score (undetermined diagnosis) in contrast enhancement ultrasound was significantly higher than that in color parametric imaging in both staff group (A) and resident group (B). CEUS: Contrast enhancement ultrasound; CPI: Color parametric imaging.

Figure 4

Spot diagram of △AT in atypical hemangioma and liver metastasis. △AT = Difference valve of peak time and arrival time of color parametric imaging of liver lesions. △AT of atypical hemangioma was significantly longer than that of liver metastasis (8.31 ± 3.05 s vs 5.13 ± 0.99 s, P < 0.001).