Skewness of HPI as a suggestive biomarker to predict development of liver metastases in patients with colorectal cancer

Purpose: Selecting texture features calculated on Computed Tomography perfusion (CTp) parameters of liver examinations in patients with colorectal-cancer to detect patients who developed metastases. Materials and Methods: 46 patients enrolled in one Centre of the PIXEL study (aiming at identifying perfusion parameters that could predict liver metastases in patients with colorectal-cancer), underwent axial liver CTp. Six of them developed liver metastases within the subsequent three-years. Perfusion analyses were carried out on selected slice through an in-house perfusion software allowing extracting Blood Flow (BF), Blood Volume (BV), Mean Transit Time (MTT), Hepatic Perfusion Index (HPI), Time to Peak (TTP), Wash-In time (Win). On these features, mean, median, skewness, and kurtosis were computed, for a total amount of 24 different features. Results: The skewness of HPI (range [-0.5÷0.6]) when coupled with mean values of BF[118÷265] ml/min/100g, BV [63÷66] ml/100g, MTT [16÷27] sec, and TTP [30÷53] sec allows detecting four out of six patients developing liver metastases with no false positives. As a general tendency, livers developing metastases seem to couple high BF values to medium alterations of HPI-skewness. Conclusions: Results highlighted the potentiality of the HPI in characterizing early vascular changes of livers, which further developed metastases due to the reshaping of the blood supplying pathways. This encourages the research on HPI-based biomarkers, thus emphasising the potential clinical role of CTp in treatments of hepatic diseases and urging improving CTp standardization to speed up its introduction in the clinical routine.