¹8F-FDG PET metabolic parameters and MRI perfusion and diffusion parameters in hepatocellular carcinoma: a preliminary study.

OBJECTIVES: Glucose metabolism, perfusion, and water diffusion may have a relationship or affect each other in the same tumor. The understanding of their relationship could expand the knowledge of tumor characteristics and contribute to the field of oncologic imaging. The purpose of this study was to evaluate the relationships between metabolism, vasculature and cellularity of advanced hepatocellular carcinoma (HCC), using multimodality imaging such as ¹8F-FDG positron emission tomography (PET), dynamic contrast enhanced (DCE)-MRI, and diffusion weighted imaging(DWI). MATERIALS AND METHODS: Twenty-one patients with advanced HCC underwent ¹8F-FDG PET, DCE-MRI, and DWI before treatment. Maximum standard uptake values (SUV(max)) from ¹8F-FDG-PET, variables of the volume transfer constant (K(trans)) from DCE-MRI and apparent diffusion coefficient (ADC) from DWI were obtained for the tumor and their relationships were examined by Spearman's correlation analysis. The influence of portal vein thrombosis on SUV(max) and variables of K(trans) and ADC was evaluated by Mann-Whitney test. RESULTS: SUV(max) showed significant negative correlation with K(trans)(max) (ρ = -0.622, p = 0.002). However, variables of ADC showed no relationship with variables of K(trans) or SUV(max) (p>0.05). Whether portal vein thrombosis was present or not did not influence the SUV max and variables of ADC and K(trans) (p>0.05). CONCLUSION: In this study, SUV was shown to be correlated with K(trans) in advanced HCCs; the higher the glucose metabolism a tumor had, the lower the perfusion it had, which might help in guiding target therapy.

MDCT and superparamagnetic iron oxide (SPIO)-enhanced MR findings of intrapancreatic accessory spleen in seven patients.

The aim of this study is to retrospectively evaluate intrapancreatic accessory spleen (IPAS) with mutidetector computed tomography (MDCT) and superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance imaging (MRI) with emphasis on the role of SPIO-MRI for the diagnosis of IPAS. Seven patients (four men and three women; mean age, 50.7 years) with IPAS underwent quadriphasic MDCT and SPIO-enhanced MRI. IPAS was diagnosed histopathologically (n = 2) or by scintigraphy (n = 5). Two radiologists evaluated CT and MRI in consensus for the location and size of each lesion and compared its attenuation on CT and signal intensity (SI) on MRI with those of the pancreas and spleen. For quantitative analysis, another radiologist calculated the mean lesional, pancreatic, and splenic attenuations or SIs on MDCT or MRI in each patient. All lesions were located in the pancreatic tail. The average lesion size was 1.5 +/- 0.5 cm. All IPASs except one appeared high-attenuating to the pancreas and were isoattenuating to the spleen on all dynamic CT phases. The IPASs were hypointense and hyperintense compared with the pancreas on unenhanced T1- and T2-weighted images, respectively, and their SI was similar to that of the spleen. On SPIO-enhanced, T2-weighted images, a similar degree of signal drop to that of the spleen was noted in all lesions. The results of the quantitative analysis were compatible with those of the subjective analysis. In most IPASs, the attenuation on CT and SI on MRI were identical to those of the spleen, and on SPIO-enhanced MRI, the degree of the signal drop in all lesions was similar to that of the spleen.