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.
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 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 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.
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.
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.
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 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.