Hepatocellular Carcinoma Screening With Computed Tomography Using the Arterial Enhancement Fraction With Radiologic-Pathologic Correlation

Abstract

Objective: The aim of this study was to investigate the performance of the arterial enhancement fraction (AEF) in multiphasic computed tomography (CT) acquisitions to detect hepatocellular carcinoma (HCC) in liver transplant recipients in correlation with the pathologic analysis of the corresponding liver explants. Materials and Methods: Fifty-five transplant recipients were analyzed: 35 patients with 108 histologically proven HCC lesions and 20 patients with end-stage liver disease without HCC. Six radiologists looked at the triphasic CT acquisitions with the AEF maps in a first readout. For the second readout without the AEF maps, 3 radiologists analyzed triphasic CT acquisitions (group 1), whereas the other 3 readers had 4 contrast acquisitions available (group 2). A jackknife free-response reader receiver operating characteristic analysis was used to compare the readout performance of the readers. Receiver operating characteristic analysis was used to determine the optimal cutoff value of the AEF. Results: The figure of merit (θ = 0.6935) for the conventional triphasic readout was significantly inferior compared with the triphasic readout with additional use of the AEF (θ = 0.7478, P < 0.0001) in group 1. There was no significant difference between the fourphasic conventional readout (θ = 0.7569) and the triphasic readout (θ = 0.7615, P = 0.7541) with the AEF in group 2. Without the AEF, HCC lesions were detected with a sensitivity of 30.7% (95% confidence interval [CI], 25.5%-36.4%) and a specificity of 97.1% (96.0%-98.0%) by group 1 looking at 3 CT acquisition phases and with a sensitivity of 42.1% (36.2%-48.1%) and a specificity of 97.5% (96.4%-98.3%) in group 2 looking at 4 CT acquisition phases. Using the AEF maps, both groups looking at the same 3 acquisition phases, the sensitivity was 47.7% (95% CI, 41.9%-53.5%) with a specificity of 97.4% (96.4%-98.3%) in group 1 and 49.8% (95% CI, 43.9%-55.8%)/97.6% (96.6%-98.4%) in group 2. The optimal cutoff for the AEF was 50%. Conclusion: The AEF is a helpful tool to screen for HCC with CT. The use of the AEF maps may significantly improve HCC detection, which allows omitting the fourth CT acquisition phase and thus making a 25% reduction of radiation dose possible. 3 The most cost-effective strategy to screen patients with chronic liver disease for HCC is sonography with testing of the serum alpha-fetoprotein level every 6 months.4 But a low sensitivity of ultrasound for HCC detection favors screening with computed tomography (CT), especially for patients on the orthotopic liver transplantation (OLT) list. 5,6 During the last few years, there were several published papers showing an increased detectability of HCC lesions with CT perfusion. 7-10Beneath the motion artefacts, 1 major limitation for CT perfusion is the high radiation dose, especially in a setting of long-duration HCC surveillance in patients on the OLT list.11 The calculation of the arterial enhancement fraction (AEF), as introduced by Kim et al,12 allows the calculation of a quantitative colored ...

Added value of spectral parameters for the assessment of lymph node metastasis of lung cancer with dual-layer spectral detector computed tomography

“…Increased angiogenesis is accompanied by an increased distribution of contrast agents in the intravascular/extravascular compartment (8), thereby resulting in a higher AEF value during the same circulatory phase. Additionally, unlike NIC and λ HU , the AEF can distinguish the relationship between different phases of the same blood circulation (26). Secondly, the spectral detector CT used in this study facilitates the simultaneous acquisition of low-and high-energy data at the same spatial and temporal position (27), which provides perfectly aligned data with significantly reduced measurement error, with no a priori decision needed for the mode of acquisition (27).…”

Clinical value of AEF in the post-processing technique of liver perfusion-like phase III enhanced CT scan in evaluating the degree of liver function impairment in patients with Hepatitis-B cirrhosis

“…In this way, abnormal blood perfusion of portal vein and portal artery occurs. [19][20][21] It has been pointed out by some studies that significant differences were observed between hAEF of cirrhosis of different severity and that of normal control group 22,23 , suggesting that the severity of patients' condition may be determined by testing hAEF. In this study, hAEF and H/S values of patients with different Child-Pugh grades were analyzed, and the results showed that the AUC of hAEF and H/S values in evaluating the degree of liver function impairment of patients were 0.716 and 0.770, respectively, indicating that hAEF and H/S values are valuable in evaluating the degree of liver function impairment of patients with hepatitis B cirrhosis.…”

Applying arterial enhancement fraction (AEF) texture features to predict the tumor response in hepatocellular carcinoma (HCC) treated with Transarterial chemoembolization (TACE)

“…Although enhanced CT is the most commonly used imaging modality in follow-up [ 22 ] appointments, several studies have reported on CT’s limitations of which we should all be aware [ 23 , 24 ]: (1) Routine enhanced CT can’t provide quantitative data [ 22 ]; (2) Lipiodol accumulation can cover or disturb the residual/recurrent enhancement inside/around the tumor [ 22 , 25 , 26 ]; (3) TACE brings the changes in tumor enhancement more often than the changes in tumor size [ 27 ]; (4) The devascularization effect of TACE can be heterogeneous and therefore difficult to manually measure [ 27 ]. Considering these shortages of routine enhanced CT, AEF can be an optional subject for investigation in the absence of AVS [ 8 , 26 , 28 ] with the following benefits: (1) AEF can improve the detection of HCC and can facilitate the detection of residual/recurrent lesions with faint arterial enhancement or slight wash-out in the portal phase [ 8 , 9 ]; (2) AEF can successfully overcome the blight of already existing lipiodol because only the area with enhancement can be highlighted and picked out by subtraction [ 26 ]; (3) TACE eliminates the feeding artery of HCC so that the AEF of a tumor decreases while the AEF of liver tissue doesn’t [ 27 ]; (4) AEF reflects the status of angiogenesis, which is a vital appearance in tumor histology [ 29 , 30 ]. These benefits enable us to correlate AEF quantification with survival data [ 27 ] and tumor response [ 31 ], and also to quantify clinical outcomes by comparing AEF before and after TACE treatment.…”

“…The unique changes in perfusion status of the disease enable the application of perfusion analysis in HCC. Currently, with the development of computer engineering, arterial enhancement fraction (AEF), which reflects the ratio of the arterial supply to the portal supply, can be derived from routine enhanced CT images by aligning and subtracting unenhanced images from arterial and portal images [ 8 , 9 ]. This provides us with a new method of perfusion analysis without subjecting patients to extra scanning and radiation exposure.…”