The importance of the iterative reconstruction ISA in diagnosing liver hemangioma

Aim: To evaluate whether the iterative reconstruction methodology ISA is superior to the standard technique of filtered back-projection. Methods: In a retrospective study, we evaluated images of 39 patients with solitary or multiple liver tumors who underwent blood pool imaging in SPECT technique in order to prove or exclude the presence of hemangioma. Results: Activity accumulations in accordance with the diagnosis of liver hemangioma could be visualized in 34 cases by the iterative, in 31 cases by the filtered back-projection methodology. As compared to filtered back-projection, the iteratively reconstructed lesions showed higher tumor-to-background ratios and were more easily distinguished from structures in their neighborhood. Furthermore, the iterative methodology resulted in a more homogenous activity distribution in the liver, whereas the inhomogenous 'patchy' structure of the liver parenchyma in filtered back-projection provokes difficulties in the distinction from reconstruction artifacts. A clearer visualization of vessels and a better distinction between the right kidney and the liver was possible by the iterative algorithm, leading to advantages in the recognition of centrally or dorsally located lesions in the right hepatic lobe. Conclusion: These data indicate that the use of our iterative algorithm in performing liver blood pool imaging yields a higher sensitivity and a better diagnostic accuracy in diagnosing liver hemangioma. (orig.)