Characterization of focal liver lesions: comparative study of contrast-enhanced ultrasound versus spiral computed tomography

Diagnosis of focal liver masses on ultrasonography: comparison of unenhanced and contrast-enhanced scans

OBJECTIVE

The purpose of this study was to compare the diagnostic accuracy, confidence level, and recommended management of focal liver masses after contrast-enhanced ultrasonography (CEUS) compared with unenhanced ultrasonography alone.

METHODS

One hundred sixty-seven patients were referred for CEUS to characterize a focal liver mass. A 2-person blind read determined benignancy or malignancy, comparative diagnosis, and accuracy on both ultrasonography and CEUS. Results were compared with the final diagnoses.

RESULTS

The 2 readers could not determine benignancy or malignancy in 77 (46.1%) and 46 (27.5%) of 167 unenhanced scans compared with 2 (1.2%) and 1 (0.6%) of 167 CEUS scans. The confidence level increased from 0 responses in the 2 highest grades (4 and 5) on the unenhanced scans to 135 (81.8%) and 132 (79.5%) of 167 at level 5 for CEUS. Regarding the diagnosis, the confidence level was lowest (grade 1) on the unenhanced scans in 128 (82.1%) and 79 (65.3%) of 167 for the 2 readers and improved to the highest (grade 5) in 110 (65.9%) and 113 (68.1%) of 167. Regarding diagnostic accuracy, the unenhanced scans agreed with the correct diagnosis in 85 (50.9%) and 63 (37.7%) of 167, and CEUS agreed with the correct diagnosis in 133 (79.6%) and 142 (85%) of 167 for readers 1 and 2, respectively. Recommendations for further imaging decreased from 166 (99.4%) and 147 (88%) of 167 on the unenhanced scans to 30 (18%) and 5 (3%) of 167 on CEUS for readers 1 and 2.

CONCLUSIONS

Contrast-enhanced ultrasonography improves the accuracy and confidence of diagnosis of focal liver lesions and reduces recommendations for further investigations.