Diffusion, Perfusion Imaging And Experimental Study Of Hepatocellular Carcinoma Precancerous Lesions Of The Liver

Part I MR Functional Diffusion-Weighted Imaging of Diffuse Liver Diseases ------Experimental Study[Abstract] Objective To investigate the value of MR Diffusion-Weighted Imaging (DWI) in the diagnosis of diffuse liver diseases. Material and Methods Using diethylnitrosamine (DEN) to induce rats liver to develop spectrum lesions. Dynamic studies of DWI were applied in different period of diffuse liver diseases (1-12 week after DEN feeding in experimental group). Comparative studies with control group and pathology were performed. Results No obvious MR morphological changes in both groups were found during this period. But DWI demonstrated heterogeneous changes in the test group at the early stage of cirrhosis. There was no significant alteration of the Apparent Diffusion Coefficient (ADC) value in the control group during this period (p>0.05). That of the test group began to decline from fifth week. Till tenth week, the ADC values of the test group decreased heavily and statistic results showed obvious difference between two groups and between the tenth week and the first to ninth week in the test group when b=300 sec/mm~2 (p<0.05). When b=600 sec/mm~2 and 1000 sec/mm~2, since sixth week had significant difference been found between two groups and between sixth week and first to fifth week in the test group (p<0.01). Pathological major changes in the test group during 1 to 4 weeks after the chemical agent administered were hepatocytes swelling, fibrous tissues hyperplasia during 5-8 week and cirrhotic nodules formation in the period of 9-12 week. Conclusion MR functional DWI could detect diffuse liver lesion earlier than conventional morphological imaging. Measurement of ADC value may be another marker for the early diagnosis of diffuse liver diseases and could be applied to inspect the lesion's changes. Part II Pilot study of MR diffusion-weighted imaging on small focal lesions in rat liver[Abstract] Aim To investigate the value of MR diffusion-weighted imaging (DWI) in the diagnosis of small focal lesions and precancerous lesion of HCC in rat liver. Material and Methods Using DWI to observe continually the changes of hepatic focal lesions from stage of precancerous to HCC in experimental models and compare with the results of pathology. Results Total 96 nodular lesions showed by DWI and proved by pathology include cyst (12), hemangioma (4), HCC (41) , dysplastic nodule ( DN) (22) and regenerative nodule (RN) (17) ? The average diameter of focal lesions showed by DWI was 0.64cm; When b was 600, the average ADC value of cyst was 2.61 ±0.06; hemangioma, HCC and DN were 2.22 ± 0.25, 1.26 ± 0.14 and 1.1 ± 0.12 respectively. The difference of ADC value between cyst, hemangioma and HCC, DN were significant (P<0.05). The ADC value of cyst decreased obviously with the increase of b value, hemangioma was followed. DN decreased slower than the parenchyma nearby and HCC was the lowest. Conclusion DWI was a sensitive way to demonstrate the small focal lesions of liver. The ADC value and the trend of the changes were helpful to the different diagnosis of these nodules. DWI could not discern DN from early HCC and RN correctly by the signal and the value of ADC. Part III Sequential hcmodynamic changes in precancerous lesions of hepatocellular carcinoma: experimental study with MR perfusion[Abstract] Objective To determine the hemodynamic changes in precancerous lesions of HCC using MR perfusion (MRP) . Material and Methods During the period of carcinogenesis (12-20w) (liver nodular lesions developed from hepatic cirrhosis during these period), 18 Wistar rats induced by DEN were scanned every week by MR perfusion and compared lesion to lesion ^ lesion to liver with pathology. Results Among 48 nodules showed by T2WI of MRI and corresponded with pathology, we identified 9 regenerative nodules (RN), 22 dysplastic nodules (DN), 10 early stage HCC (eHCC) and 5 HCC. The positive enhancement integral (PEI) of fourcategories of nodules and liver parenchyma nearby was 205.67 ± 31.17, 161.94 ± 20.74, 226.09 ± 34.83, 491.86 ± 44.61 and 204.84 ± 70.19 respectively. Comparing the blood perfusion index between nodule and surrounding hepatic parenchyma, we found no difference with RNs (t=-5.303, P=0.06). There were significant differences with dysplastic nodules (t=-3.63, P=0.02) which manifested decreased blood perfusion. 4 of 10 early HCCs demonstrated less blood perfusion and 6 displayed minor increased blood flow. 5 HCC showed typical increased blood supply with significant difference (t=3.74, P=0.02). Conclusion Non-invasive MR perfusion imaging could detect the changes of blood perfusion in precancerosis of hepatocellular carcinoma. Blood perfusion of HCC increased and DN decreased when compared with surrounding hepatic parenchyma.Part IV Preliminary experimental study of CT perfusion in hepatitis, hepatic fibrosis and early stage of cirrhosis[Abstract] Objective To investigate the value of CT perfusion in the early diagnosis of diffuse hepatic diseases. Material and Methods 14 male Wistar rats of control group and 14 of test group at different stages of hepatitis, hepatic fibrosis, hepatic cirrhosis induced with diethylnitrosamine (DEN) , were studied with CT perfusion. CT perfusion data of different stages were compared and pathologic analysis was performed. Results Density-time curves of CT perfusion were satisfactory and all perfusion data could be obtained. During the period of hepatitis developing into early stage of hepatic cirrhosis, hepatic artery flow (HAF) tended to increase in the test group. The average of HAF in stage of hepatitis, fibrosis and cirrhosis were (0.33 ±0.23)%, (0.55 + 0.13)% and (0.7 ±0.24 ) %. Mean transmit time (MTT) prolonged obviously, they were (6.6 + 2.39) s, (11.41+3.92) s, (15.02 + 5.21) s respectively at three stages. Blood flow (BF) and volume (BV) declined, decreased from (18.05 + 3.27) ml/lOOg and (152.84 + 59.12) ml/lOOg/min in hepatitis into (9.51 + 3.61) ml/lOOg and (117.59 + 78.66) ml/lOOg/min in cirrhosis., While in the control group, HAF declined slightly, MTT, BV and BF increased. Statistic analysis showed that the differences of HAF and MTT at different stages between the control and the...