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.
Objective To summarize the principle and application of functional MR imaging of pancreatic carcinoma and chronic mass-forming type pancreatitis. Methods Articles about diffusion-weighted imaging (DWI), magnetic resonance spectrum imaging (MRSI) and dynamic contrast-enhanced MR imaging of pancreatic carcinoma and chronic pancreatitis were reviewed and analyzed. Results Functional MR imaging could reflected the differences in molecules diffusion, metabolism and tissue perfusion between pancreatic carcinoma and chronic pancreatitis. Conclusion As a non-invasive protocol, functional MR imaging can provide useful information in differential diagnosis between chronic mass-forming type pancreatitis and pancreatic carcinoma.
Objective To review the examination techniques and the current research progress of the magnetic resonance diffusion weighted-imaging (DWI) used in liver. Methods The recent and relevant literatures about the principles and the current study situation of liver DWI were scrutinized and analyzed retrospectively. In addition, the existing problems of liver DWI were discussed. Results DWI could demonstrate the normal and abnormal structure and function through measuring the diffusion motions of water molecule in the liver. With the improving technology and better understanding of diffusion dynamics, DWI has been used for the diagnosis and differential diagnosis for hepatic diseases. Conclusion DWI as a non-invasive examine method, may provide valuable functional information for clinical diagnosis and treatment.
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.
ObjectiveTo evaluate the values of diffusion weighted imaging (DWI) sequence in the diagnosis of node metastases in breast cancer by meta-analysis. MethodsThe articles concerning the diagnosis of node metastases by using DWI until September 2016 were searched in databases including The Cochrane Library, PubMed, EMbase, Web of Science, CBM, VIP, WanFang Data and CNKI. Two reviewers independently screened literature, extracted data, and assessed the risk of bias of included studies by using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) tool. Then, meta-analysis was performed by using Stata 12.0 software. The pooled weighted sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated, the summary receiver operating characteristic curve (SROC) was drawn and the area under the curve was calculated. ResultsA total of 21 articles were included, involving 25 studies. The results of meta-analysis showed that, the pooled sensitivity, specificity, DOR and area under SROC curve of DWI for diagnosing node metastases were 0.85 (95%CI 0.80 to 0.89), 0.83 (95%CI 0.78 to 0.87), 4.99 (95%CI 3.74 to 6.67), 0.18 (95%CI 0.13 to 0.24), 3.32 (95%CI 2.82 to 3.82), and 0.91 (95%CI 0.88 to 0.93), respectively. The results of subgroup analysis showed that DWI had better Spe in b value=750-1 000 than b value=400-600; The 1.5T DWI had better Sen and Spe in diagnosing node metastases compared with 1.5T DWI. ConclusionDWI has more diagnostic efficiency for assessing lymph node metastases, especially in b value=750-1 000 and 1.5T field MR syetem. Due to limited quantity and quality of the included studies, more high-quality studies are required to verify the above conclusion.
ObjectiveTo discuss the evaluation of clinical grading for neonates with hypoxic-ischemic encephalopathy (HIE) by diffusion weighted imaging (DWI). MethodsWe retrospectively analyzed the DWI findings of 39 neonates with HIE diagnosed by clinical criteria from December 2009 to July 2013. Abnormal signals were observed for 23 neonates (59%). These neonates were divided into three groups (group A, B and C) according to the shape and range of abnormal signals. Then Kappa test was performed between groups of different clinical grading (light, medium, severe). ResultsFor groups arranged based on abnormal signals and clinical grading, the Kappa value of the consistency test was 0.797 (P < 0.001). ConclusionsDWI negativity cannot exclude the existence of HIE. However, when abnormal signals occur, we can infer the severity in neonates with HIE according to the shape and range of abnormal signals by DWI.
Objective To evaluate the role of apparent diffusion coefficients (ADC) in assesment of response to chemotherapy in patients with gastrointestinal liver metastasis. MethodsTen patients with liver metastasis （8 from colorectal cancer， 1 from gastric cancer， 1 from esophageal cancer） at Peking University People’s Hospital from April 2006 to April 2007 were included. All of them received chemotherapy （FOLFOX6： 4 cases， XELOX： 3 cases, and FOLFIRI： 1 case in 8 cases of colorectal liver metastases; ECF: 1 case of gastric liver metastases; DCF: 1 case of esophageal liver metastasis）. ADC were calculated after MR duffusionweight imaging exmination (GE MEDICAL SYSTEMS HD EXCITE 1.5 T) 1 month pre-and post-chemotherapy, respectively. Tumour response to chemotherapy was assessed by RECIST criteria. ResultsTumors with low pretreatment ADC (lt;9.04×10－4 mm2/s) responded better to chemotherapy than that with high ADC (gt;9.04×10－4 mm2/s); pretreatment ADC of cases (6/10) were remarkable lower than those of cases (4/10)， P＝0.033. Increased ADC after onemonth chemotherapy in patients with liver metastasis predicted a better response. ConclusionsLow pretreatment ADC is predictive of better response to chemotherapy. An increased ADC after treatment predicts a better response to chemotherapy.
目的 探讨囊性脑膜瘤的磁共振表现、表观弥散系数（ADC）图的影像特点、ADC值与病理分级的关系及ADC值对判断不同病理亚型脑膜瘤的价值。 方法 回顾性分析2003年3月－2007年12月18例经病理证实的囊性脑膜瘤患者的磁共振表现，其中男8例，女10例，平均年龄45.6岁。在ADC图上分别测量肿瘤实质、瘤周水肿、囊变区的平均ADC值（均取4～6个区域，取平均值），比较不同病理亚型、不同病理分级的肿瘤实质、瘤周水肿、囊变区的ADC值差异是否有统计学意义。 结果 良恶性脑膜瘤肿瘤实质ADC值差异无统计学意义（P＞0.05）；囊性脑膜瘤各亚型间的肿瘤实质、瘤周水肿的ADC值差异无统计学意义（P＞0.05）；肿瘤实质、囊变区与瘤周水肿平均ADC值相比差异均有统计学意义（P＜0.05）。 结论 ADC值可区分肿瘤实质、囊变区及瘤周水肿，但对脑膜瘤亚型及良恶性的甄别需结合常规MRI与增强的征象。Objective To explore the MRI imaging manifestation, features of apparent diffusion coefficient (ADC) map and the relationships among ADC value, pathologic grading and pathologic subtype of cystic meningioma. Methods The clinical data of 18 patients (8 males and 10 females, with an average age of 45.6 years) with cystic meningiomas confirmed by pathologically examination were retrospectively analyzed. The ADC values of tumor parenchyma, peritumoral edema, cystic regions and the contralateral normal brain of the tumor parenchyma were measured and analyzed.The ADC value of the tumor parenchyma, peritumoral edema, cystic region were measured and then compared with the pathological findings. P value of less than 0.05 was considered as having a statistically significant difference. Results There was no significant difference in ADC values between benign and malignant meningioma and also among the tumor parenchyma, periedema and cystic region in different pathological subtypes. The difference in ADC values amongst tumor parenchyma, peritumoral edema and cystic region were statistically significant (P＜0.05). Conclusions Although ADC quantitative measurement allows the differentiation of the tumor parenchyma, cystic region and peri-edema, it is need to combined with conventional MR examination to assess tumor malignancy as well as grading in cystic meningioma.