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.
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 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 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 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 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.
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.