Classification of Hypervascular Liver Lesions Based on Hepatic Artery and Portal Vein Blood Supply Coefficients Calculated from Triphasic CT Scans

Abstract

Perfusion CT of the liver typically involves scanning the liver at least 20 times, resulting in a large radiation dose. We developed and validated a simplified model of tumor blood supply that can be applied to standard triphasic scans and evaluated whether this can be used to distinguish benign and malignant liver lesions. Triphasic CTs of 46 malignant and 32 benign liver lesions were analyzed. For each phase, regions of interest were drawn in the arterially enhancing portion of each lesion, as well as the background liver, aorta, and portal vein. Hepatic artery and portal vein blood supply coefficients for each lesion were then calculated by expressing the enhancement curve of the lesion as a linear combination of the enhancement curves of the aorta and portal vein. Hepatocellular carcinoma (HCC) and hypervascular metastases, on average, both had increased hepatic artery coefficients compared to the background liver. Compared to HCC, benign lesions, on average, had either a greater hepatic artery coefficient (hemangioma) or a greater portal vein coefficient (focal nodular hyperplasia or transient hepatic attenuation difference). Hypervascularity with washout is a key diagnostic criterion for HCC, but it had a sensitivity of 72 % and specificity of 81 % for diagnosing malignancy in our diverse set of liver lesions. The sensitivity for malignancy was increased to 89 % by including enhancing lesions that were hypodense on all phases. The specificity for malignancy was increased to 97 % (p=0.039) by also examining hepatic artery and portal vein blood supply coefficients, while maintaining a sensitivity of 76 %.

Quantitative Measurements of Enhancement on Preprocedure Triphasic CT Can Predict Response of Colorectal Liver Metastases to Radioembolization

“…1). The HAC and PVC provide an estimate of the blood volumes of the hepatic artery and portal vein for each tumor [10]. The AEF provides an estimate of the blood volume of the hepatic artery divided by the total blood volume [11].…”

“…We recently developed a method for estimating the hepatic artery and portal vein blood supply to each portion of the liver, using standard triphasic CT [10]. These perfusion parameters provide an estimate of the fraction of the volume of each pixel that is occupied by microscopic branches of the hepatic artery and portal vein.…”

“…These perfusion parameters provide an estimate of the fraction of the volume of each pixel that is occupied by microscopic branches of the hepatic artery and portal vein. Using this method, we were able to quantitate the increased hepatic artery perfusion in hepatocellular carcinoma and the decreased portal perfusion in cirrhotic livers [10]. …”

Role of Computed Tomography Perfusion Compared to Computed Tomography Triphasic Study in Assessment of Hepatic Focal Lesions

“…One goal of perfusion CT is to improve detection and characterization of liver lesions compared to standard triphasic imaging 4 .…”

Triphasic CT Liver Characterization and Color Data Fusion

“…Hypervascular masses (which cover more than 75% of liver tumors [11]) have increased hepatic artery coefficients compared to the liver [1] and show hyper enhancement in the arterial phase. In the successive phases, when the enhancement of the surrounding liver overtakes that of the hypervascular mass, this finding is referred to as "negative enhancement," or washout [2].…”