Image enhancement in computerized tomography for sensitive diagnosis of liver cancer and semiquantitation of tumor selective drug targeting with oily contrast medium

Abstract

A new type of anticancer agent with an amphiphilic nature, poly(styrene‐co‐maleic acid)‐conjugated neocarzinostatin (Smancs), was dissolved in lipid contrast medium Lipiodol (Smancs/Lpd, Gelbet Co., Paris, France). This medium was injected arterially and found to be an invaluable tool for highly sensitive computerized tomography (CT) image analysis of tumors. After the administration, CT images revealed high‐density areas which corresponded to the location and size of liver cancer, the smallest being 4 mm in diameter. The deposition pattern of Smancs/Lpd in liver cancers by CT was classified into three types. In type A, Lipiodol was distributed relatively even in the tumor lesion, whereas in type B it was accumulated predominantly around the tumor's periphery although the central portion remaining low in density. A few cases exhibited type C pattern, which was a mixture of types A and B. Type A was found essentially in primary liver cancer, and types B and C in secondary liver cancer. Thus, the CT pattern was found to be useful for differential diagnosis. For a sufficient therapeutic effect, 0.08 ml of Smancs/Lpd per cm² of the maximal CT cross‐section of the tumor area was found to be necessary. As a routine protocol after Smancs/Lpd administration, CT scanning was recommended for primary liver cancer initially at 1 week and then once every month. Secondary liver cancer required more frequent CT follow‐ups after the administration (on the third day, after 1 and 2 weeks, and every month) due to relatively rapid disappearance of the stain than in the primary liver cancer.