Perfusion characterization of liver metastases from endocrine tumors:Computed tomography perfusion

AIM:To assess prospectively parameters of computed tomography perfusion(CT p) for evaluation of vascularity of liver metastases from neuroendocrine tumors.METHODS:This study was approved by the hospital’s institutional review board.All 18 patients provided informed consent.There were 30 liver metastases from neuroendocrine tumors.Patients were divided into three groups depending on the appearance of the liver metastases at the arterial phase of morphological CT(hyperdense,hypodense and necrotic).Sequential acquisition of the liver was performed before and for 2 min after intravenous injection of 0.5 mg/kg contrast medium,at 4 mL/s.Data were analyzed using deconvolution analysis to calculate blood flow(BF),blood volume(BV),mean transit time(MTT),hepatic arterial perfusion index(HAPI) and a bi-compartmental analysis was performed to obtain vascular permeability-surface area product(PS).Post-treatment analysis was performed by a radiologist and regions of interest were plotted on the metastases,normal liver,aorta and portal vein.RESULTS:At the arterial phase of the morphological CT scan,the aspects of liver metastases were hyperdense(n=21),hypodense(n=7),and necrotic(n=2).In cases of necrotic metastases,none of the CT p parameters were changed.Compared to normal liver,a significant difference in all CT p parameters was found in cases of hyperdense metastases,and only for HAPI and MTT in cases of hypodense metastases.No significant difference was found for MTT and HAPI between hypo-and hyperdense metastases.A significant decrease of PS,BV and BF was demonstrated in cases of patients with hypodense lesions PS(23±11.6 mL/100 g per minute) compared to patients with hyperdense lesions;PS(13.5±10.4 mL/100 g per minute),BF(93.7±75.4 vs 196.0±115.6mL/100 g per minute) and BV(9.7±5.9 vs 24.5 10.9 mL/100 g).CONCLUSION:CT p provides additional information compared to the morphological appearance of liver metastases.