Objective To investigate the value of MR diffusion-weighted imaging (DWI) in differentiating pancreatic carcinoma from chronic focal pancreatitis on 3.0 T MR system. Methods Thirteen patients with proved pancreatic carcinoma, 7 patients with confirmed chronic focal pancreatitis, and 14 healthy volunteers, were included in this study. MR examination including the routine abdomen scanning protocol and DWI was performed for both patients and volunteers. The SE-EPI sequence and ASSET technique were used for DWI. The b values of 400, 600, 800 and 1 000 s/mm2 were selected to acquire the DWI. The corresponding apparent diffusion coefficient (ADC) values were measured in each designated region of interest and statistically analyzed. Results ①DWI of the healthy volunteers showed intermediate signals of pancreas. ②DWI of pancreatic tumor masses showed homogenous high signal intensity relative to the surrounding pancreatic tissue with clear boundary. Under different b values, the tumor ADC values were (1.63±0.235)×10-3 mm2/s, (1.42±0.126)×10-3mm2 /s, (1.36±0.170)×10-3 mm2 /s and (1.26±0.178)×10-3 mm2 /s respectively, which were significantly lower than those of non-tumor region 〔(2.11±0.444)×10-3 mm2 /s, (1.83±0.230)×10-3 mm2 /s, (1.81±0.426)×10-3 mm2 /s, (1.60±0.230)×10-3 mm2 /s〕 and of the normal pancreas 〔(1.85±0.350)×10-3 mm2 /s, (1.69±0.290)×10-3 mm2 /s, (1.67±0.268)×10-3 mm2 /s, (1.42±0.221)×10-3 mm2 /s〕， P＜0.05. ③DWI of chronic focal pancreatitis showed inhomogeneous slightly hyper-intense signal with blurring borders. Under different b values, the ADC values of the inflammatory masses of chronic pancreatitis were (169±0.150)×10-3 mm2 /s, (1.56±0.119)×10-3 mm2 /s, (1.59±0.172)×10-3 mm2/s and (1.35±0.080)×10-3 mm2 /s respectively, which were higher than those of pancreatic carcinoma. When b value was set to 800 s/mm2 , the difference in ADC values between pancreatic carcinoma and chronic focal pancreatitis was statistically significant (P＜0.05). Conclusion MR DWI can clearly depict the tumor mass of pancreatic carcinoma. In addition, the measurement of ADC values can provide useful information for the differential diagnosis between pancreatic carcinoma and chronic focal pancreatitis.
This study aims to detect early changes of kidney in patients with primary hypertension by 3.0 T functional magnetic resonance imaging (fMRI). 26 patients with primary hypertension (hypertension group) and 33 healthy volunteers (control group) underwent conventional and functional magnetic resonance scans, which included blood oxygen level-dependent (BOLD) MRI, diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI). We measured renal cortical thickness (CT), parenchymal thickness (PT), and functional values of renal cortex and medulla including R2* value, apparent diffusion coefficient (ADC) value and fractional anisotropy (FA) value in each group, and then calculated the cortical/parenchymal thickness ratio (CPR). Compared with those in the control group, CT and CPR in hypertension group were larger (P<0.01), cortical and medullar R2* values increased (P<0.01) whereas medullar FA values decreased (P<0.05). It could be well concluded that noninvasive 3.0 T functional MRI would have important clinical significance in identifying early abnormalities of kidney in hypertension patients.
ObjectiveTo investigate the value of diffusion weighted imaging (DWI) combined with three-dimensional volumetric interpolated breath-hold examination (3D-VIBE) in evaluating metastatic lymph nodes secondary to hilar cholangiocarcinoma. MethodsFrom July 2009 to March 2011, DWI examination was performed in 37 patients with hilar cholangiocarcinoma, which was compared with 3D-VIBE sequences. The morphological characteristics and distribution were analyzed for metastatic and nonmetastatic lymph nodes. Signal intensity (SI) was measured on DWI images and apparent diffusion coefficient (ADC) was calculated for each lymph node. The SI of lymph nodes (SILN） and liver (SIliver) were also measured and the ratio of SI was calculated. The ADC and the ratio of SI were compared between metastatic and nonmetastatic lymph nodes. ResultsThere were fifty-nine groups of lymph nodes in 37 patients with hilar cholangiocarcinoma, fifty-one groups were revealed in both DWI and 3D-VIBE sequences, and eight groups were only demonstrated in one sequence (P=0.070). The short diameters were (1.05±0.42) cm and (0.78±0.22) cm on 3D-VIBE images for metastatic and nonmetastatic lymph nodes, respectively (P=0.030). The ADC value in metastatic lymph nodes was (1.64±0.3)×10-3 mm2/s, which was significantly lower than that in nonmetastatic lymph nodes 〔(2.28±0.79)×10-3 mm2/s〕 on DWI images (P=0.033). There were no significant differences in SILN/SIliver between metastatic and nonmetastatic lymph nodes on images of portal venous phase and 3 min delayed contrast-enhanced phase. ConclusionsDifferences of ADC and short diameter can provide valuable information to differentiate metastatic lymph nodes with nonmetastatic lymph nodes. When combined with 3D-VIBE sequence, DWI is more effective in evaluating metastatic lymph nodes secondary to hilar cholangiocarcinoma.
ObjectiveTo explore the value of magnetic resonance diffusion weighted imaging (DWI) in preoperative Bismuth-Corlette classification of hilar cholangiocarcinoma (HCCA). MethodsA total of 53 HCCA patients confirmed by postoperative pathology were retrospectively included. The accuracy of two sequence combinations, namely dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) + magnetic resonance cholangiopancreatography (MRCP) and DCE-MRI + MRCP + DWI, in evaluating the longitudinally involved bile duct segments and Bismuth-Corlette classification of HCCA was compared. Additionally, the correlation between apparent diffusion coefficient (ADC) values and tumor Bismuth-Corlette classification as well as degree of differentiation was analyzed. ResultsThere were 318 bile duct segments in 53 HCCA patients. The accuracy rate of DCE-MRI + MRCP was 93.7% (298/318), the sensitivity was 91.5% (161/176), and the specificity was 96.5% (137/142). The accuracy rate of DCE-MRI + MRCP + DWI was 96.5% (307/318), the sensitivity was 96.0% (169/176), and the specificity was 97.2% (138/142). Receiver operating characteristic (ROC) curve analysis showed that the area under the ROC curve (AUC) of DCE-MRI + MRCP + DWI was 0.966 [95%CI (0.940, 0.983), P＜0.001], and its diagnostic efficacy was superior to that of DCE-MRI + MRCP [AUC=0.940, 95%CI (0.908, 0.963), P＜0.001]. The DeLong test indicated a statistically significant difference in AUC between the two sequences (Z=2.633, P＜0.01). The accuracy rates of preoperative Bismuth-Corlette classification of HCCA evaluated by DCE-MRI + MRCP and DCE-MRI + MRCP + DWI were 86.8% (46/53) and 94.3% (50/53), respectively. After adding the DWI sequence, the consistency between Bismuth-Corlette classification results and surgical pathological classification results (Kappa=0.922, P<0.001) was higher than that of DCE-MRI + MRCP sequence (Kappa=0.820, P<0.001), with a statistically significant difference (χ2=160.370, P<0.001). In addition, the ADC value of HCCA was negatively correlated with tumordegree of differentiation (rs=–0.524, P<0.001), but had no significant correlation with its Bismuth-Corlette classification (rs=–0.058, P=0.682). ConclusionsDCE-MRI + MRCP + DWI sequence can effectively improve the accuracy in preoperative evaluation of the involvement of bile duct segments and Bismuth-Corlette classification of HCCA, which provides guidance for precise preoperative surgical planning in clinical practice. In addition, the ADC value can provide additional information required for non-invasive preoperative prediction of the prognosis of HCCA patients.
Objective To investigate the magnetic resonance imaging （MRI） assessment and functional evaluation of chronic pancreatitis （CP）. Methods Literatures about MRI assessment of CP （especially the evaluation of pancreatic exocrine function with MRI） were reviewed. Results Some early parenchymal changes （pancreatic size，signal intensity of pancreas， and enhancement pattern） in the CP could be visualized by MRI；ductal changes could be visualized by MR cholangiopancreatography （MRCP）；and secretin-stimulated MRCP （combination of both morphologic and functional evaluation） not only improved the visualization of pancreatic duct and side branches，but also allowed evaluation of the pancreatic exocrine function noninvasively. Secretin-stimulated diffusion weighted imaging also could be used as a noninvasive method to assess pancreatic exocrine function. Conclusions Conventional MRI and （or） secretin-stimulated MRI can become valuable means in CP （especially early-stage CP）， with furnishing morphologic and functional information simultaneously. However，further research is needed to verify the diagnostic accuracy of these modalities.
ObjectiveTo analyze findings of 3.0 T diffusion weighted magnetic resonance (MR) in hepatic alveolar echinococcosis and evaluate potential role of apparent diffusion coefficients (ADC) in hepatic alveolar echinococcosis. MethodsThe clinical data of 26 patients with hepatic alveolar echinococcosis from November 2013 to January 2015 in this hospital were analyzed retrospectively. Hepatic MR scannings with diffusion weighted imaging (DWI) sequences (b-value=0, 600, 1 000, and 1 200 s/mm2) were performed in 26 patients with hepatic alveolar echinococcosis. The data of all the patients were stored to the PACS. The lesion features including type, size, distribution, location, and calcification (on the CT) were assessed by two deputy radiologists. TheADCvalues of marginal area, centre area, surrounding area of liver parenchyma tissue were measured at different b values (0, 600, 1 000, and 1 200 s/mm2) and compared. Results①There were 26 patients with a total of 29 lesions, of which involved multiple liver segments, 21 (72%) lesions located in the right lobe, 4 lesions involved simultaneously the left and right lobes. Twenty-four lesions invaded the hepatic vein or portal vein, 20 lesions invaded the intrahepatic bile duct, 10 lesions invaded the right adrenal gland. Seven patients occurred hilar and retroperitoneal lymph nodes metastases, 5 patients occurred pulmonary metastasis, 3 patients occurred brain metastasis, while 3 patients occurred lung and brain metastases simultaneously. ②There were 20 liquefied necrotic lesions, of which 5 lesions marginal area had multiple small round cysts in T2WI, 15 were only solid and without small cyst; The DWI of the centre area in 12 lesions showed a high signal, 8 lesions showed a low signal. There were 9 solid lesions, of which 2 lesions marginal area had multiple small round cysts in T2WI, 7 lesions marginal area were only solid and without cyst in T2WI. The DWI of the solid lesions showed a low signal, there was a "ring" high signal in the edge of lesions. ③At the same b value, theADCvalue of the centre area in the liquefied necrosis lesions were significantly higher than that in the solid lesions (P<0.01). At different b values, theADCvalue of the surrounding liver parenchyma tissue was significantly lower than that of the marginal area (P<0.01) and the centre area (P<0.01) in the liquefied necrosis lesions; theADCvalue of the centre area was significantly higher than that of the marginal area or surrounding liver parenchyma tissue (P<0.05, P<0.01) in the solid lesions. ConclusionsDWI could clearly distinguish structure and composition of hepatic alveolar echinococcosis and has a higher value in distinguishing from other liver dieases. The averageADCvalue of centre area in liquefied necrotic lesions is higher than that in solid lesions.