Perfusion-CT analysis for assessment of hepatocellular carcinoma lesions: diagnostic value of different perfusion maps

Abstract

Background Computed tomography liver perfusion (CTLP) has been improved in recent years, offering a variety of perfusion-parametric maps. A map that better discriminates hepatocellular carcinoma (HCC) is still to be found. Purpose To compare different CTLP maps, regarding their ability to differentiate cirrhotic or non-cirrhotic parenchyma from malignant HCC. Material and Methods Twenty-six patients (11 cirrhotic) with 50 diagnosed HCC lesions, underwent CTLP on a 128-row dual-energy CT system. Nine different maps were generated. Regions of interest (ROIs) were positioned on non-tumorous parenchyma and on HCCs found on previous magnetic resonance imaging. Perfusion parameters for non-cirrhotic and cirrhotic livers were compared. Receiver operating characteristic (ROC) analysis was employed to evaluate each map's ability to discriminate HCCs from non-tumorous livers. Comparison of ROC curves was performed to evaluate statistical significance of differences in the discriminating efficiency of derived perfusion maps. Results Perfusion parameters for non-tumorous liver and HCCs recorded in cirrhotic patients did not significantly differ from corresponding values recorded in non-cirrhotic patients ( P > 0.05). The highest power for HCC discrimination was found for the maximum-slope-of-increase (MSI) parametric map, with estimated the area under ROC curve of 0.997. An MSI cut-off criterion of 2.2 HU/s was found to provide 96% sensitivity and 100% specificity. Time to peak, blood flow, and transit time to peak were also found to have high discriminating power. Conclusion Among available CTLP-derived perfusion parameters, MSI was found to provide the highest diagnostic accuracy in discriminating HCCs from non-tumorous parenchyma. Perfusion parameters for non-tumorous livers and HCCs were not found to significantly differ between cirrhotic and non-cirrhotic patients.

Current Imaging Diagnosis of Hepatocellular Carcinoma

“…In addition, progressed HCC lesions exhibited significant changes in perfusion parameters related to hypervascularity (increased BF and BV, decreased MTT) and permeability (increased PS) as expected. These observations have been confirmed in multiple studies in patients [ 86 , 87 , 88 , 89 ]. Among available CT perfusion parameters that are based on pharmacokinetic models, Fischer et al found that a cut-off value of ≥85% HPI exhibited a sensitivity of 100%, while a cut-off value of ≥99% HPI yielded a specificity of 100% for the detection of HCCs in cirrhotic patients ( Figure 8 , [ 88 ]).…”

“…Among available CT perfusion parameters that are based on pharmacokinetic models, Fischer et al found that a cut-off value of ≥85% HPI exhibited a sensitivity of 100%, while a cut-off value of ≥99% HPI yielded a specificity of 100% for the detection of HCCs in cirrhotic patients ( Figure 8 , [ 88 ]). Recently, Hatzidakis et al highlighted that even descriptive perfusion parameters, such as the mean slope of increase, might offer high accuracy in discriminating HCC lesions from normal parenchyma ( Figure 9 , [ 89 ]). Other studies have demonstrated differences in CT perfusion parameters between HCC and hemangiomas [ 98 , 99 , 100 ], liver metastases [ 101 , 102 , 103 ], or arterioportal shunts [ 104 ], indicating that CTLP might be a useful tool for differential diagnosis between HCC and other focal liver lesions ( Table 7 ).…”

Differences Between CT-Perfusion and Biphasic Contrast-enhanced CT for Detection and Characterization of Hepatocellular Carcinoma: Potential Explanations for Discrepant Cases

“…In the past decade, perfusion-CT (PCT) has advanced to a more sensitive imaging technique compared to multiphase-CT as it enables quantification of blood supply for both tumor and liver using a separate assessment of the arterial and portal-venous blood supply (5,6). This technique increases the sensitivity of CT scans for detecting HCC-suspicious liver lesions as it measures the arterial contribution to the tumor blood supply on the background of non-involved liver parenchyma, which generally exhibits a consistently lower level of arterialization (7). Hence, liver masses can not only be better detected, but also characterized in terms of the magnitude of blood flow (BF), blood volume (BV), vessel wall permeability (k-trans) and in particular with respect to the degree of arterial versus portal-venous vascular supply.…”

“…The latter reflects differences in the mix (arterial±portal-venous) of blood supply between HCC, dysplastic nodules, and regenerative nodules (8). The enhanced tumor-to-liver contrast generated by arterial liver perfusion (ALP) or hepatic perfusion (HPI) color-coded maps is essential for lesion detection, also enabling the depiction of smaller (<10 mm) lesions (6,7). Previous comparative studies between biphasic or triphasic contrast-enhanced-CT and PCT have underlined the superiority of the latter (9, 10).…”

Prognostic value of computed tomographic perfusion in the diagnosis of liver fibrosis and cirrhosis. Pilot study

“…Перфузионная компьютерная томография (КТ-перфузия) печени -метод лучевой диагностики, который используется для дифференциальной диагностики объемных образований и оценки результатов лечения [6][7][8]. Кроме того, этим методом можно количественно оценивать гемодинамические изменения в ткани печени, в том числе возникающие в результате прогрессирования фиброза и цирроза [9].…”