They are particularly useful for the arterial phase. Contrast media are also highly

useful for the delayed phase of CT. (grade A) Based on studies using CTHA, it has been known for a very long time that clinically malignant hepatocellular carcinomas show greater arterial blood flow than the surrounding liver tissue (LF062091 level 3). In CO2 ultrasound angiography, the mean doubling time of tumors with increased arterial blood flow was 70 days, and the mean doubling time of nodules with a poor arterial blood flow was 370 days; thus, hypovascular tumors MEK inhibitor have been reported to grow more slowly (LJ033682 level 3). In recent studies using CTHA and CTAP, a correlation between the histological degree of differentiation (e.g. dysplastic nodule to well-differentiated hepatocellular carcinoma, moderately- or poorly-differentiated hepatocellular carcinoma) and the tumor vascularity has been demonstrated, reflecting the multistage growth of hepatocellular carcinoma (LF062043 level 2a, LF057244 level 2a). Hepatocellular carcinomas with increased arterial blood flow may be the main targets of diagnosis and treatment. Dynamic studies using iodine-enhanced CT and extracellular Gd-enhanced MRI improve the detection rate

of hypervascular hepatocellular carcinomas. In a study selleck inhibitor using early-period angiographic findings as the standard, a diagnosis was made in 88% of the cases based on a combination of non-contrast CT and arterial phase CT (LF025385 level 1). A subsequent study revealed that addition of a delayed phase to the arterial phase increased the diagnostic rate of CT (LF057106 level 1). Dynamic MRI study has also been demonstrated to be highly useful among imaging techniques, and the arterial phase is quite important for detecting hypervascular hepatocellular carcinomas many (LF058397 level 1). In a study of the livers of liver

transplant recipients, the detection rates of hepatocellular carcinoma were 76.9% for high-resolution MRI, 53.8% for single helical CT and 46.2% for ultrasonography, showing the superiority of MRI (LF020018 level 1). For minimizing individual differences in the appropriate timing of imaging of the arterial phase, the time required for contrast injection should be fixed for all contrast media (LF120829 level 2a). Superparamagnetic iron oxide used for MRI is taken up by reticuloendothelial cells, leading to a decrease in the signal intensity of the liver parenchyma. Reticuloendothelial cells are not present in a tumor, and the signal intensity does not decrease. Diagnosis is made based on these characteristics. A good degree of correlation has been reported between the degree of differentiation of hepatocellular carcinoma and the SPIO uptake in SPIO-MRI (LF0620210 level 3). When focusing only on the detection capability of hepatocellular carcinoma, the extracellular Gd contrast agent is superior to SPIO (LF0218211 level 1, LF0573412 level 1).