ROLE OF SPIRAL CT IN ASSESSMENT OF FOCAL HEPATIC LESIONS

Abstract

1- Spiral CT imaging of the liver is the preferred scanning technique for evaluation of hepatic focal lesions. 2- The vascularity of liver lesion determines which phase of study it will be more clearly seen in it. 3- The combination of HAP and PVP imaging help in detection and characterization of hypervascular lesions. 4- PVP images are generally sufficient for evaluation ofhypovascular hepatic lesions. 5- The patter ofperipheral enhancement regarding its continuity, shape, and degree help in differentiating haemangiomas from other hepatic lesions in single phase (PVP imaging) study. 6- With HAP & PVP imaging studies, more specific diagnostic signs for haemangiomas will be found. The feeding arterial branch may appear on HAP imaging. However, the centripetal spread of contrast and retention of contrast over long period in targeted delayed scans confirm the diagnosis of haemangiomas. 7- Large solid lesions (3cm) associated with cirrhosis, are most likely HCCs. No benign lesions were found in cirrhotic livers larger than 3cm in diameter. On the other hand, focal lesions less than 3cm in diameter in cirrhotic livers need HAP imaging studies. Hypervascularity of such lesions appear clearly on HAP, which is specific for malignancy. Hypovascularity in such lesions need further diagnostic tests. &- Hepatic metastases differ according to their primary tumors. Most of hepatic metastases are hypovascular (appear clearly in PVP imaging), and some of hepatic metastases from hypervascular primary tumor are hypervascular and are best seen in HAPimaging. 9- Hepatic Lymphomas are hypovascular lesions and clearly seen in the PVP imaging.