Early changes in apparent diffusion coefficient as an indicator of response to sorafenib in hepatocellular carcinoma.

OBJECTIVE: The relationship between apparent diffusion coefficient (ADC) and chemotherapy has been established. However, whether ADC could be considered as a measure for monitoring response to sorafenib in hepatocellular carcinoma (HCC) has not been demonstrated. This study was to investigate the ADC changes of advanced HCC under sorafenib treatment. METHODS: Athymic mice with HepG2 xenografts were allocated to two groups: control and sorafenib (40 mg/kg, bid). T2 and diffusion images were acquired at each time point (0, 10, 14, and 18 d post-therapy). Tumor volume and changes in ADC were calculated. RESULTS: Tumor volumes on Days 10, 14, and 18 after treatment showed significant decreases in the sorafenib-treated group compared with the control. Pretreatment ADC values were not significantly different between the control and treated groups. A slow increase in ADC in the peripheral zone of tumors appeared in the treated group, which was significantly higher compared with the control group on Days 10, 14, and 18. In the central part of tumors on Day 10 after treatment, an increase in ADC appeared in the treated and control groups, the ADC of the control group being significantly lower compared with the treated tumors. From Day 10 to Day 14, the ADC map showed a progressive decrease in the central region of tumors in the treated and control groups. However, this change is more significant in the treated groups. CONCLUSIONS: Early changes in mean ADC correlated with sorafenib treatment in HCC, which are promising indicators for predicting sorafenib response in this carcinoma.

[CT and MRI findings in patients with autoimmune pancreatitis].

OBJECTIVE: To evaluate computed tomography (CT) and magnetic resonance imaging (MRI) findings in patients with autoimmune pancreatitis (AIP). METHODS: The imaging findings of pancreas and extra-pancreas in 24 patients with AIP were retrospectively reviewed. Among them, CT scan was performed in 18 patients, MRI in 11, and bGth CT and MRI in 10. RESULTS: The pancreas showed diffuse enlargement (25%, 6/24), focal enlargement (37. 5%, 9/24), combined enlargement (25%, 6/24) ,and no enlargement (12. 5%, 9/24). Unenhanced CT showed hypoattenuation in AIP area (n = 2) . After intravenous injection of contrast medium, 17 patients showed abnormal contrast enhancement in the affected pancreatic parenchyma, including hypoattenuation during the arterial phase (50%, 9/18) and hyper attenuation during the delayed phase (94. 4%, 17/18). Precontrast MRI showed abnormal signal intense (n =9), including hypointense on T1-weight images (T1 WI) (n = 7), hyperintense (n = 7) and hypointense (n = 2) on T2-weight images (TIWI). Enhanced MRI demonstrated abnormal contrast enhancement within lesions (n = 11), including hypoattenuation during the arterial phase (81. 8%, 9/11) and good enhancement during the delayed phase (100%, 11111). A capsule-like rim was seen around pancreas (37. 5%, 9/24), among which CT detected in 6 out of 18 patients and MRI found in 7 out of 11 patients.The main pancreatic duct lumen within lesions has no visualization (100%, 24/24) and upstream dilation of the main pancreatic duct (n = 8) , ranging from 2. 2 to 4. 5 mm(mean 3. 1 0. 47 mm) in diameter. Narrowing of the common bile duct was shown in 14 patients. Miscellaneous findings were: infiltration of extrapancreatic vein (n = 9) and artery (n = 1); mild fluid collection around pancreas (n = 2); pseudocysts (n = 3). Fourteen patients also presented one or more of the following extrapancreatic imaging findings: narrowing of the intra-hepatic bile duct or hilar duct (n = 5); thickening of gallbladder wall (n = 5); fibrosis in mesenteric (n = 2), in retroperitoneal (n = 2) and in ligamentum teres hepatis (n = 1); renal involvement (n = 3); peri-pancreatic or para-aortic lymphadenopathy (n = 10); and ulcerative colitis (n = 3). CONCLUSION: AIP display some characteristic CT and MRI imaging features: sausage-like change of the pancreas; capsule-like rims around lesions; delayed contrast enhancement in the affected pancreatic parenchyma; segment or diffuse pancreatic duct stenosis but mild upstream dilation and extrapancreatic organs involvement. CT and MRI findings combining with serological tests and pancreas biopsy can assist physicians to make accurate and timely diagnosis.