[Study of blood flow in liver hemangiomas using radionuclide angiography]

Hepatic radionuclide angiography (HRA) is a recognised method of investigation of liver blood flow disorders caused by: diffuse and focal diseases of liver parenchyma or disorders of blood flow in extrahepatic liver vessels. Hepatic perfusion index (HPI) based on Sarper's slope method is significantly lower in patients with e.g. liver cirrhosis, malignant primary and metastatic liver diseases and portal vene thrombosis, but not in patients with benign focal liver leasions. Determined in liver as a whole, HPI is a sensitive indicator of the presence of malignant liver tumours, but is within normal range in patients with hepatic hemangioma. The aim of the study was to investigate characteristic of blood flow in hemangioma itself, separately from but in relation to the liver blood flow, using hepatic radionuclide angiography. We have examined 12 patients with liver hemangioma confirmed mainly by positive 99mTc-labeled red blood cell scintigraphy, which diagnostic specificity for liver hemangiomas is near 100%. 8/12 hemangiomas resulted in photopenic areas on angioscintigrams, indicating lower blood flow, and rest were isoactive to surrounding liver tissue. Regions of interest have been delineated around the photopenic areas (hemangiomas) and surrounding liver tissue. Time-activity curves have been generated and slope of the fitted hepatic artery and (portal) venous portions of the hemangioma and liver curves have been determined. Perfusion indexes of hemangioma (PIH) and liver (HPI) have been calculated from the slopes, expressing portal venous flow as a portion of entire blood flow to the region. In addition, times of arrival and transit of intravenous bolus of 99mTc-pertechnetate through the hemangioma and liver tissue have also been derived from time-activity curves. Slope of the venous portion of the hemangioma time-activity curve is significantly lower then that of the venous portion of the liver curve (p < 0.01). So that, perfusion index of hemangioma (PIH = 0.34 +/- 0.12 (mean +/- SD) is significantly lower then hepatic perfusion index (HPI = 0.57 +/- 0.08) (p < 0.05). Bearing in mind interference of superimposed liver activity with that of hemangioma, these results indicate that liver hemangiomas are dominantly if not exclusively irrigated by hepatic artery branches. There are no data regarding relation between arterial and venous blood flow in liver hemangiomas determined by HRA. Obtained results are in harmony with arteriography data which confirm slow arterial blood flow through hemangiomas. Portal venous inflow of some angiomatous liver lesions in infants and children, and arterio-portal shunting in hemangiomas have been rarely reported. Results of this study indicate that regional determination of perfusion index and other HRA parameters in patients with focal liver lesion enables differentiation between tissues with different intensity and pattern of blood flow. The method could be used in examination of vascularisation pattern of other focal liver lesions.