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.
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 explore the differences in the detection of vigabatrin-associated brain abnormalities on MRI by different MRI sequences, so as to further guide the clinical understanding of VABAM and improve the appropriate imaging sequences. MethodsA total of 353 patients with infantile spasm or epileptic spasm who were admitted to the Epilepsy Center of Yuquan Hospital of Tsinghua University from January 2020 to January 2023 were retrospectively included. MRI was performed in 131 cases, including 3D T1, T2, T1- fluid-attenuated inversion recovery sequence (FLAIR) images, DWI and ADC sequences, of which 65 cases taking VGB. We aim to evaluate the detection of vigabatrin-associated brain abnormalities on MRI by different MRI sequences in these children. Results Among the 65 patients, VABAM was detected in 23 cases, the detection rate was 35.4%. The average dosage of vigabatrin was 100.73±35.54 mg/(kg·d). The positive detection rates of VABAM were 95.7% in DWI sequence, 26.1% in ADC sequence, 21.3% in FLAIR sequence, 4.3% in T2 sequence and 0 in T1 sequence. The detection rate of ADC sequence was significantly different from DWI sequence and T1 sequence, but not from T2 sequence and FLAIR group. ConclusionDWI sequence has irreplaceable advantages in the detection rate of VABAM. Therefore, for patients with infantile spasm and epileptic spasm who take vigabatrin, we should try our best to add DWI sequence scanning to improve the positive detection rate and avoid clinical symptoms, so as to avoid further brain damage.
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.
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.
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.
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.