Is the arterial enhancement fraction (AEF) a suitable biomarker for detection residual or recurrent hepatic tumors after locoregional therapy?
Abstract
Objectives: We investigated whether the use of arterial enhancement fraction (AEF) during the evaluation of multiphasic contrast-enhanced computed tomography (CECT) improves the assessment of viable tumor tissue after locoregional therapy in liver tumors. We tested how the use of the AEF influences the accuracy of tumor residue detection in differently experienced evaluators.
Methods: Two differently experienced radiologists independently evaluated CT images of patients who met the criteria of our study. CT documentation was evaluated first separately and then in combination with AEF color maps.
The evaluators assessed the presence of a residue of viable tumor tissue, and measured it, in case of a positive finding. The same documentation was evaluated by two experienced radiologists (with more than 10 years of experience).
One of them performed the same evaluation as young radiologists, the other evaluated only CT with AEF and took into account the clinical information and further development of the disease. Both experienced evaluators compared the results of their evaluation and their agreement resulted in a reference value to which the findings of young radiologists were compared.
The results were statistically analyzed. Results: The documentation of 70 patients was evaluated.
Viable tumor tissue was detected in 40 of them. The addition of AEF to the standard CT documentation slightly increased the sensitivity in both young evaluators, but significantly increased the specificity in intermedialy experienced radiologist (from 56.6% to 96.6%, p = 0.0004) in novice (36.7% to 73,7%, p = 0.0089).
Similarly, the precision of tumor size measurement has improved significantly for both. Conclusion: Using AEF as a part of CECT in monitoring after locoregional treatment of liver tumor increases the detection capability and accuracy of viable tumor tissue measurement.
The greatest effect was seen in a low-experienced radiologist. AEF is calculated from triphasic CECT examination without increasing radiation dose and its assesment is not time-consuming.