摘要:目的: 探討臂叢神經磁共振成像的技術方法及其可行性。 方法 :對15例正常志愿者行雙側臂叢神經成像:包括常規快速自旋回波序列T1加權(T1W/TSE)、快速自旋回波序列T2加權(T2W/TSE)、快速自旋回波序列T2加權加SPIR脂肪抑制(T2W/SPIR)冠狀位掃描以及彌散加權背景抑制成像序列(DWIBS)軸位掃描。 結果 :T1W/TSE、T2W/TSE、及T2W/SPIR對臂叢節后神經同層顯示率分別為533%、567%和833%;DWIBS MIP重建圖像對臂叢神經的全貌顯示較為完整、清晰、直觀;T1W/TSE、T2W/TSE、T2W/SPIR及DWIBS MIP重建圖像的對比噪聲比分別為109±09、107±13、185±68和299±133,T2W/SPIR序列和DWIBS MIP重建圖像的對比噪聲比明顯高于T1W/TSE和T2W/TSE序列。 結論 :T2W/SPIR序列對臂叢神經的同層顯示率及圖像的對比噪聲比明顯高于常規T1W/TSE、T2W/TSE序列, DWIBS MIP重建圖像能夠顯示臂叢神經的全貌,兩者為臂叢神經成像較為有效的技術方法,對于臂叢神經病變的診斷即具有十分重要的意義。Abstract: Objective: To determine the optimal sequences of brachial plexus with MRI. Methods : Fifteen volunteers were underwent MRI on 15T scanner, the Sequences of T1W/TSE/COR, T2W/TSE/COR, T2W/SPIR/COR and Diffusionweighted imaging with background body signal suppression were performed. Results : The display rates of brachial plexus postganglionic segment nerve showing at the same slice were 533%, 567% and 833% on T1W/TSE/COR, T2W/TSE/COR, T2W/SPIR/COR. Brachial plexus on DWIBS MIP were clear and complete. Contrastnoise ratio of four sequences was 109±09, 107±13, 185±68 and 299±133,respectively. Contrastnoise ratio of T2W/SPIR/COR and DWIBS MIP was significantly higher than that of the other two sequences. Conclusion : Display rate of brachial plexus and contrastnoise ratio of images on T2W/SPIR/COR were higher than those of routine sequences. Image of DWIBS MIP can show the outline of brachial plexus clearly. The two sequences were reliable and effetive techoniquic in diagnosis of brachial plexus lesion.
Because of the long acquisition time and spin-echo planar imaging sequence, diffusion weight magnetic resonance image (DWI) should be denoised effectively to ensure the follow-up applications. The commonly used denoising methods which induced from gray level image lack the use of the specific information from multiple magnitude directions. This paper, therefore, proposes a modified linear minimum mean square error (LMMSE) denosing method used for DWI. The proposed method uses the local information to estimate the parameter of the Rician noise and modifies the LMMSE using the information of multiple magnitude directions synthetically. The simulation and experiment of the synthetic DWI and real human brain DWI dataset demonstrate that the proposed method can more effectively remove the Rician noise compared to the commonly used denoising method and improve the robustness and validity of the diffusion tensor magnetic resonance image (DTI).
Cryptogenic stroke (CS) accounts for 25% of ischemic stroke. The etiology of undetermined stroke is unclear leading to untargeted secondary prevention, high recurrence rate, so the clinical burden of cryptogenic stroke is substantial. Cardiac magnetic resonance (CMR) imaging can identify more occult cardiac embolism that cannot be identified by standard cardiac assessment based on its excellent spatial resolution and contrast, three-dimensional imaging capacity and ability to depict soft tissues, to accelerate the initiation of optimal secondary prevention and improve the prognosis of patients. This review summarizes the application of CMR in the field of CS in recent years. Based on the latest evidence of diagnosis and management strategies, this paper proposes a cardiac diagnostic examination plan for CS patients, thereby improving the secondary prevention strategy of CS patients and improving their quality of life.
Objective To explore the accuracy of contrast-enhanced magnetic resonance imaging (MRI) in predicting pathological complete remission (pCR) in breast cancer patients after neoadjuvant therapy (NAC). Methods The clinicopathological data of 245 patients with invasive breast cancer who had completed the surgical resection after NAC in the Affiliated Hospital of Southwest Medical University from March 2020 to April 2022 were collected retrospectively. According to the results of hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) detected by immunohistochemistry, all patients were divided into four subgroups: HR+/HER2–, HR+/HER2+, HR–/HER2+ and HR–/HER2–. The value of MRI in evaluating the efficacy of NAC was analyzed by comparing the postoperative pathological results as the gold standard with the residual tumor size assessed by preoperative MRI. Meanwhile, the sensitivity, specificity and positive predictive value (PPV) of pCR predicted by the evaluation results of enhanced MRI were analyzed, and further analyzed its predictive value for pCR of different subtypes of breast cancer. Results There were 88 cases (35.9%) achieved radiological complete response (rCR) and 106 cases (43.3%) achieved pCR in 245 patients. Enhanced MRI in assessing the size of residual tumors overestimated and underestimated 12.7% (31/245) and 9.8% (24/245) of patients, respectively. When setting rCR as the MRI assessment index the specificity, sensitivity and PPV were 84.2% (117/139), 62.3% (66/106) and 75.0% (66/88), respectively. When setting near-rCR as the MRI assessment index the specificity, sensitivity and PPV were 70.5% (98/139), 81.1% (86/106), and 67.7% (86/127), respectively. The positive predictive value of both MRI-rCR and MRI-near-rCR in evaluating pCR of each subtype subgroup of breast cancer was the highest in the HR–/HER2+ subgroup (91.7% and 83.3%, respectively). In each subgroup, compared with rCR, the specificity of near-rCR to predict pCR decreased to different degrees, while the sensitivity increased to different degrees. Conclusions Breast contrast-enhanced MRI can more accurately evaluate the efficacy of localized breast lesions after NAC, and can also more accurately predict the breast pCR after NAC. The HR–/HER2+ subgroup may be a potentially predictable population with pCR exemption from breast surgery. However, the accuracy of the evaluation of pCR by breast enhancement MRI in HR+/HER2– subgroup is low.
The in-vivo electron paramagnetic resonance (EPR) method can be used for on-site, rapid, and non-invasive detection of radiation dose to casualties after nuclear and radiation emergencies. For in-vivo EPR spectrum analysis, manual labeling of peaks and calculation of signal intensity are often used, which have problems such as large workload and interference by subjective factors. In this study, a method for automatic classification and identification of in-vivo EPR spectra was established using support vector machine (SVM) technology, which can in-batch and automatically identify and screen out invalid spectra due to vibration and dental surface water interference during in-vivo EPR measurements. In this study, a spectrum analysis method based on genetic algorithm optimization neural network (GA-BPNN) was established, which can automatically identify the radiation-induced signals in in-vivo EPR spectra and predict the radiation doses received by the injured. The experimental results showed that the SVM and GA-BPNN spectrum processing methods established in this study could effectively accomplish the automatic spectra classification and radiation dose prediction, and could meet the needs of dose assessment in nuclear emergency. This study explored the application of machine learning methods in EPR spectrum processing, improved the intelligence level of EPR spectrum processing, and would help to enhance the efficiency of mass EPR spectra processing.
One of the main technical challenges when integrating magnetic resonance imaging (MRI) systems with medical linear accelerator is the strong interference of fringe magnetic fields from the MRI system with the electron beams of linear accelerator, making the linear accelerator not to work properly. In order to minimize the interference of magnetic fields, a magnetic shielding cylinder with an open structure made of high permeability materials is designed. ANSYS Maxwell was used to simulate Helmholtz coil which generate uniform magnetic field instead of the fringe magnetic fields which affect accelerator gun. The parameters of shielding tube, such as permeability, radius, length, side thickness, bottom thickness and fringe magnetic fields strength are simulated, and the data is processed by MATLAB to compare the shielding performance. This article gives out a list of magnetic shielding effectiveness with different side thickness and bottom thickness under the optimal radius and length, which showes that this design can meet the shielding requirement for the MRI-linear accelerator system.
Objective To explore the application value of time of flight magnetic resonance angiography (TOF-MRA) in target bypass surgery for moyamoya disease. Methods The data of patients with moyamoya disease in Affiliated Drum Tower Hospital, Medical College, Nanjing University between May 1 and August 30, 2020 were retrospectively analyzed. Patients were divided into navigation group and control group according to whether navigation technology was used during operation. All patients completed TOF-MRA evaluation before operation, and all patients completed surgical treatment. One week after operation, TOF-MRA was reviewed to evaluate the patency of anastomotic stoma. The intraoperative and postoperative conditions of the two groups were compared. Results Finally, 48 patients with moyamoya disease were included. 22 patients who used intraoperative navigation were included in the navigation group, and 26 patients with moyamoya disease who did not use intraoperative navigation in the same period were included in the control group. There was no significant difference between the two groups in gender, age, Suzuki stage before operation, proportion of posterior circulation involvement, proportion of bleeding type, proportion of hypertension and proportion of diabetes (P>0.05). The operation duration [(3.3±0.4) vs. (3.6±0.6) h] and postoperative hospital stay [(7.3±1.9) vs. (8.8±2.7) d] in the navigation group were shorter than those in the control group (P<0.05). There was no significant difference between the two groups in the proportion of patients who completed bypass surgery, the proportion of middle meningeal artery retained, the postoperative patency rate, the proportion of temporary dysfunction, and the proportion of serious complications (P>0.05). Conclusion TOF-MRA sequence combined with navigation technology can effectively guide the surgical scheme design and postoperative evaluation of moyamoya disease.
OBJECTIVE:To investigate the diagnostic meaning of MRI in intraocular tumors. METHODS:Forty-six cases of confirmed intraocular tumors,including choroidal melanoma(20 cases),retinoblastoma(18 cases),Coats disease(6 cases)and choroidal hemangioma(2 cases),were studied with MRI and compared with ultrasonography and CT. RESULTS:In making discoveries about intraocular tumors,there were no sighificant difference between MRI and B-ultrasonography or CT （P＞0.03，chi;2=1.0716）while there were highly statistic sighificance in dediding characters and position （P＜0.01，deceding character chi;2=29.8314，positionchi;2=13.659）of them. CONCLUSION:Among the examinations to find out about the position,character and secondary pathological insults of in traocular tumors MRI might be more available than CT and ultrasonography. （Chin J Ocul Fundus Dis,1997,13:93-95 ）
ObjectiveTo detect the metabolites of the serum and joint fluid from rabbits’ osteoarthritis model with 1H nuclear magnetic resonance spectroscopy (NMR) technique, study the metabolic differences and connections of serum, synovial and cartilage of rabbits after the articular cavity injection of sodium hyaluronate, and explore osteoarthritis and metabolic mechanism in the process of treating sodium hyaluronate using sodium hyaluronate, thus provide new ideas and basis of the specific mechanisms in the treatment of osteoarthritis via sodium hyaluronate.MethodsWe selected 30 healthy New Zealand white rabbits, 6 months old, and randomly divided them into three groups as follows: blank control group, model phosphate buffer saline (PBS) liquid injection group and model injection of sodium hyaluronate group, with 10 rabbits in each group. Ten weeks after surgery, all experimental animals were put to death and observed in correlation studies regarding general condition, imaging examination, and histological examination. Metabolites 1H NMR detection and data preprocessing were performed in the serum and joint fluid samples.ResultsThe results considering general condition, general sample observation, imaging examination and histology indicated advantages in sodium hyaluronate group over PBS group. Metabolomics analysis showed statistically significant changes of metabolites in the serum and joint fluid compared with the PBS group and the blank control group (P<0.05). According to the relevant ways of differences metabolites retrieval, analysis found that the effect of sodium hyaluronate on osteoarthritis might be related to protein biosynthesis, amino acid circulation, the metabolic process of pyruvic acid, gluconeogenesis and other metabolic pathways.ConclusionsBased on the research of 1H-NMR metabolomics, the results suggest that the effect of sodium hyaluronate on osteoarthritis is mainly related with the activation of protein metabolism, abnormal lipid and energy metabolic pathways. This study provides new ideas and basis on the concrete mechanism in the treatment of knee osteoarthritis using sodium hyaluronate.
ObjectiveTo investigate the value of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid enhanced magnetic resonance imaging (Gd-EOB-DTPA-MRI) in gross morphological classification of hepatocellular carcinoma (HCC). MethodsThe clinicopathologic data of patients with HCC who received surgical treatment in the Affiliated Huai’an Hospital of Xuzhou Medical University from January 2017 to December 2022 were retrospectively gathered. The Gd-EOB-DTPA-MRI was performed before operation. Two radiologists independently assessed the gross morphological classification of HCC according to the imaging performance. The tumors were cut into sections in a coronal plane and were taken pictures for recording pathological features after operation. The tumors were assigned into 4 types according to the references and clinical experiences: single nodular type (SN), single nodular with extranodular growth type (SN-EG), confluent multi-nodular type (CMN), and infiltration type (IF). Matching degree of morphological classification was analyzed between by the Gd-EOB-DTPA-MRI and resected specimen. The pathological features of 4 types of HCC were also analyzed. ResultsA total of 87 patients with HCC were included. The gross morphological classification by the Gd-EOB-DTPA-MRI was 28 (32.2%) patients with SN, 28 (32.2%) patients with SN-EG, 21 (24.1%) patients with CMN, 10 (11.5%) patients with IF, which by the resected specimen was 33 (37.9%) patients with SN, 24 (27.6%) patients with SN-EG, 21 (24.1%) patients with CMN, and 9 (10.4%) patients with IF in the 87 patients with HCC. The Kappa’s coefficient of agreement between the results of Gd-EOB-DTPA-MRI and postoperative resection specimens was 0.776 (P=0.199). There were statistical differences in the tumor diameter and microvascular invasion (MVI) among the 4 types of gross morphology classification (F=2.937, P=0.038; χ2=16.852, P=0.001), the MVI rate was highest and tumor diameter was biggest in the patients with IF among the 4 types of gross morphology classification (P<0.05). ConclusionsFrom the results of this study, the gross morphological classification of HCC is closely related to the tumor diameter and MVI. Results of Gd-EOB-DTPA-MRI and postoperative resection specimens in assessing the gross morphological classification are good agreement. Therefore, an accurate preoperative planning and better therapy strategy for the patients with HCC can be provided according to gross morphological classification by preoperative Gd-EOB-DTPA-MRI.