To what extent can diverse types of liver lesions mimic hemangiomas? A retrospective quantitative analysis of masses found to be positive in SPECT/CT with labeled blood cells – a preliminary report

Abstract

SummaryBackgroundAlthough specificity of SPECT/CT examination using technetium-99m radiolabeled red blood cells (Tc-99m-RBC) for detection of liver hemangiomas is very high, it is still not perfect. It is possible to overlook a malignancy. Moreover, the difference in accumulation of RBCs between a hemangioma and uninvolved liver remains unknown.The aim of the study is to determine the quotients of accumulation of Tc-99m-RBC in hemangiomas and in normal liver parenchyma (HEM/liv), and to verify, whether the quotient could be potentially helpful in distinguishing hemangiomas from other RBC-accumulating liver masses.Material/Methods34 liver lesions larger than 1.5 cm classified scintigraphically (qualitatively) in our Department as either typical or suspicious of hemangioma 1.5–4 years earlier were enrolled in this retrospective study. Their SPECT/CT images were acquired 1 hour after in vivo labeling of RBCs with Tc-99m. In reconstructed images, ellipsoidal regions of interest (ROIs) with diameters of about 1.5 cm were created in the assessed lesions (HEM) and in the uninvolved liver parenchyma (liv). The HEM/liv quotients were calculated for each mass. The results were compared with radiological data.Results31 lesions were found to be clinically and radiologically typical for hemangiomas, their HEM/liv ratios were at least 1.6 (smaller masses) or 1.8 (larger masses). One lesion with HEM/liv ratio equal to 1.21 was classified as metastasis. Two lesions with HEM/liv 1.42 and 1.46 were classified as benign foci other than hemangioma.ConclusionsThe quantitative analysis can be preliminarily proposed as a helpful tool in the assessment of possible liver hemangiomas.