Quantitatively defining washout in hepatocellular carcinoma

Area of Science:

• Radiology
• Hepatology
• Oncology

Background:

• Washout on delayed phase imaging is a key indicator for hepatocellular carcinoma (HCC).
• Quantitative definitions can reduce variability in diagnosing HCC.
• Accurate HCC diagnosis is crucial for patient management and treatment planning.

Purpose of the Study:

• To quantitatively define washout in pathologically proven hepatocellular carcinoma (HCC).
• To establish a quantitative metric for HCC detection to minimize interobserver variability.
• To facilitate more accurate diagnosis of HCC using CT imaging.

Main Methods:

• Analysis of 47 liver lesions in 24 patients undergoing triphasic MDCT.
• Identification of hyperenhancing lesions in the arterial phase.
• Calculation of percentage attenuation ratio (lesion to adjacent liver attenuation) on delayed phase images.

Main Results:

• A statistically significant difference in percentage attenuation ratio was found between HCC and non-HCC lesions (median 121 vs. 101).
• A percentage attenuation ratio threshold of ≥ 107 achieved 100% sensitivity and 75.8% specificity for HCC detection.
• The quantitative metric correlated well with radiologists' assessments of lesion enhancement profiles.

Conclusions:

• Simple CT attenuation measurements, specifically the percentage attenuation ratio, provide excellent sensitivity, specificity, PPV, and NPV for HCC detection.
• This quantitative approach demonstrates very good correlation with radiologists' assessments of washout.
• The percentage attenuation ratio offers a reliable method for quantitative HCC diagnosis on delayed phase CT imaging.