Aiming at motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging (MRI), we proposed a joint correction method in this paper to correct the two kinds of artifacts simultaneously without additional acquisition of navigation data and field map. We utilized the proposed method using multi-shot variable density spiral sequence to acquire MRI data and used auto-focusing technique for image deblurring. We also used direct method or iterative method to correct motion induced phase errors in the process of deblurring. In vivo MRI experiments demonstrated that the proposed method could effectively suppress motion artifacts and off-resonance artifacts and achieve images with fine structures. In addition, the scan time was not increased in applying the proposed method.
ObjectiveThis review has summarized in detail the advances in computed tomography (CT) and magnetic resonance imaging (MRI) imaging in evaluating the efficacy of targeted therapy for gastrointestinal stromal tumor (GIST).MethodsTo summarize the image-related guidelines, consensus, international conference reports, and relevant knowledge of clinical research on the evaluation of the efficacy of GIST targeted therapy in recent years.ResultsThe CT and MRI manifestation after targeted treatment of GIST was closely related to pathological changes, including necrosis, cystic degeneration, and bleeding. CT was the preferred imaging method. Functional magnetic resonance imaging, such as diffusion weighted imaging (DWI), had made some progress. The main criteria for evaluating the efficacy of GIST targeted therapy were RECIST 1.1 and Choi criteria.ConclusionCT and MRI play an important role in evaluating the efficacy of targeted therapy for GIST.
摘要:目的:探討平山病的MRI影像特點及其臨床應用價值。方法:5例臨床確診平山病病例組和10例正常對照組進行頸椎自然位及屈頸位MRI檢查,矢狀位T1WI、T2WI及軸位T2WI,觀察頸髓、蛛網膜下腔及硬膜外腔變化情況。結果:病例組的5例平山病均系16~20歲男性。自然位:5例下位頸髓均萎縮變扁,硬膜外間隙未顯示增寬。屈頸位:5例C5~7頸髓前移變扁中,將變扁頸髓又分為上中下三段,以中段最窄,上下段漸移行至正常;C5~7蛛網膜下腔亦變窄,硬脊膜伴隨前移;而C4~7硬脊膜后間隙則增寬,呈新月形影,增寬程度分為輕、中、重三度,最重者位于C6椎體平面,T2加權像及T1WI增強呈高信號,其中1例內見血管流空信號影。對照組為10例志愿者,自然位: 4例C3~7頸髓形態、大小基本一致,6例頸髓自頸3逐漸移行與胸1脊髓其大小一致;屈頸位:頸髓和蛛網膜下腔大小與自然位比較無明顯變化,硬膜后間隙自C3平面向下延至T1平面,T2WI上呈均勻線樣高信號影。結論:下位頸髓萎縮變扁,屈頸位頸髓及硬脊膜前移、硬脊膜后間隙增寬呈新月形影等,是臨床診斷平山病較特征性的MRI表現。Abstract: Objective: To evaluate clinical value and MRI features of Hirayama disease. Methods: Five cases of hirayama disease, which had been clinically confirmed using siemens sonata 1.5T MRI scan, physiological condition and flexional condition, Sagittal view T1WI, T2WI and Axial View T2WI, and GdDTPA enhanced examination, for MRI changes of spinal cord, subarachnoid cavity, duramater of spinal membrae and extra dural space, etc were studied. Results: In case group of 5 cases of hirayama disease, age was mainly in 16–20 years old, All of 5 cases were men. Which were pressed and become thinner of spinal cord, strictic changes of subarachnoid cavity, new moony shape and enlargement changes and pushed forward of extra duramater space, and higher intensity signal of GdDTPA enhancement, and vascular flow effect (one case ) in C5–C7. but also, for contrast group 10 cases of normal volunteer, physiological condition:4 cases in cervical spinal cord with shape and structure were uniformity, and duramater, subarachnoid cavity, extra duramater space etc in C3–C7 were abnormal. Six cases in cervical spinal cord with shape and structure gradully changed from C3 to T1; flexional condition: 10 cases of MRI changes of spinal cord, subarachnoid cavity were as same as it in physiological condition,all of T2 WI, higher intensity signal were homogeneous of extraduramater space in C3–T1. Conclusion: The feature findings of cervical spinal cord became thinner, and cervical cord, durameter pussed forward, new moony shape and enlargment of extradurameter space, vascular flow effusion, etc in MRI were useful value for clinical diagnosis.
Coronary microcirculation dysfunction (CMVD) is an important risk factor for the prognosis of re-perfused ischemic heart. Recent studies showed that the evaluation of CMVD has significant impact on both the early diagnosis of heart diseases relevant to blood supply and prognosis after myocardial reperfusion. In this review, the definition of CMVD from the perspective of pathophysiology was clarified, the principles and features of the state-of-the-art imaging technologies for CMVD assessment were reviewed from the perspective of engineering and the further research direction was promoted.
Objective To summarize the research progress of magnetic resonance imaging (MRI) in evaluating microvascular invasion (MVI) of hepatocellular carcinoma (HCC) in order to provide information and evidence for therapy of HCC. Methods Papers published from May 1950 to May 2017, were retrieved in PubMed, OVID, CNKI database using the keywords on hepatocellular carcinoma, microvascular invasion, and magnetic resonance imaging. Sixty-seven papers were retrieved in English literatures and 13 in Chinese literatures. Criteria of paper adoption: ① the imaging method was MRI; ② the assessment content was MVI of HCC; ③ the golden standard was postoperative pathologic diagnosis. fifty-four papers were finally analyzed and reviewed. Results Currently there were various ways to evaluating the MVI of HCC using MRI, including morphology, texture analysis, diffusion-weighted imaging, dynamic-enhanced MRI, fat assessment, hepatocellular function and comprehensive evaluation. Conclusions Various methods perform differently in evaluating MVI. The use of multiparametric MRI techniques offers the potential for comprehensive assessment of MVI of HCC.
The aim of this paper is to reveal the change of the brain function for nicotine addicts after smoking cessation, and explore the basis of neural physiology for the nicotine addicts in the process of smoking cessation. Fourteen subjects, who have a strong dependence on nicotine, have agreed to give up smoking and insist on completing the test, and 11 volunteers were recruited as the controls. The resting state functional magnetic resonance imaging and the regional homogeneity (ReHo) algorithm have been used to study the neural activity before and after smoking cessation. A two factors mixed design was used to investigate within-group effects and between-group effects. After 2 weeks’ smoking cessation, the increased ReHo value were exhibited in the brain area of supplementary motor area, paracentral lobule, calcarine, cuneus and lingual gyrus. It suggested that the synchronization of neural activity was enhanced in these brain areas. And between-group interaction effects were appeared in supplementary motor area, paracentral lobule, precentral gyrus, postcentral gyrus, and superior frontal gyrus. The results indicate that the brain function in supplementary motor area of smoking addicts would be enhanced significantly after 2 weeks’ smoking cessation.
Objective To compare diagnosis values of computed tomography (CT) and magnetic resonance imaging (MRI) in preoperative staging of rectal carcinoma. Methods The imaging data of 81 patients with rectal carcinoma from January 2013 to January 2017 in the Hefei Second People’s Hospital were retrospectively analyzed. Based on the postoperative pathological results, the diagnostic accordance rates of CT and MRI on the T staging and N staging were calculated. Results The sensitivities of the CT and MRI on the preoperative T staging of rectal carcinoma were 69.1% (56/81) and 82.5% (52/63), the difference was not statistically significant (χ2=3.396, P=0.065), the Kappa values was 0.521 and 0.371, respectively, the MRI on the T staging was in a good agreement with the pathological diagnosis. The sensitivitie of the T1-2, T3, and T4 stagings with CT was 70.0%, 66.7%, and 72.0%, respectively, with MRI was 83.3%, 83.3%, and 81.0%, respectively, which had no significant difference respectively between the CT and the MRI. The areas under the receiver operating characteristic curve of the T1-2, T3, and T4 stagings with the CT and MRI were 0.809, 0.689, 0.798 and 0.897, 0.826, 0.869, respectively. The sensitivities of the CT and MRI on the preoperative N staging of rectal carcinoma were 59.3% (48/81) and 65.1% (41/63), the difference was not statistically significant (χ2=0.509, P=0.476), the Kappa values were 0.371 and 0.463, respectively. The sensitivities of the N0, N1, N2 stagings with CT were 64.7%, 45.5%, 64.0%, with MRI were 70.3%, 63.2%, 72.5%, which had no significant difference respectively between the CT and the MRI. Conclusions Results of in this study show that MRI is superior to CT for judgment of tumor infiltration. Neither CT nor MRI is able to provide satisfactory assessment of lymph node metastasis.
ObjectiveTo investigate the feasibility of proton magnetic resonance spectroscopy (1H-MRS) imaging, by which to quantitatively analyze liver fat content for therapeutic evaluation of fatty liver at 3.0 T MRI. MethodsTwenty-six patients who diagnosed with fatty liver were examined with proton MRS at Siemens Trio Tim 3.0 T MRI before treatment and 3, 6 months after treatment, respectively. The water peak, fat peak, water peak area, and fat peak area were detected, and the relative lipid content 1 (RLC1) and relative lipid content 2 (RLC2)were calculated. Fatty liver index (FLI) was referred to the standard which was calculated from triglycerides (TG), gammaglutamyl-transferase (GGT), waist circumference, and body mass index. ResultsThere were significantly different differences of RLC1 and RLC2 among before treatment and 3, 6 months after treatment (Plt;0.05). Compared with before treatment, the RLC1 and RLC2 values significantly decreased on month 3 or 6 after treatment (Plt;0.05). There were positive correlation between RLC1 or RLC2 and FLI (r=0.476, Plt;0.00; r=0.475, Plt;0.001). The intraclass correlation coefficient was more than 0.75 before treatment, the repeatability was better. ConclusionsProton MRS can quantitatively measure liver fat content. It can be reliably used for dynamic monitoring the therapeutic effects for fatty liver. Proton MRS is accurate, and has a good clinical application in dynamically monitoring the progression of fatty liver and evaluating the therapeutic effects of various treatments.
Objective To investigate the accuracy of preoperative high-resolution magnetic resonance imaging (MRI) scans to predict tumor stage, lymph node stage, and circumferential resection margin (CRM) involvement. Methods Between September 2006 and May 2009, 42 patients with histologically proven rectal cancer by the colonoscopic biopsy in Peking Union Medical College Hospital were staged preoperatively using MRI. All of the patients underwent total mesorectum excision (TME) operation within 1 week after MRI examination. The specimens were reported according to the 2002 TNM staging system for primary colorectal cancer of the American Joint Committee on Cancer (AJCC). Concordance between radiologic staging of tumor, local lymph node, and CRM involvement and pathologic reporting was assessed by means of the Kappa statistic.Results For all of 42 patients, MRI correctly staged the tumor in 36 patients, understaged in 3 patients and overstaged in 3 patients. Statistically, there was a better correlation between pathologic and radiologic tumor staging (Kappa=0.731, P=0.000). MRI correctly staged lymph node status in 31 patients, understaged in 5 patients and overstaged in 6 patients. Statistically, there was a common correlation between pathologic and radiologic lymph node staging (Kappa=0.410, P=0.009). MRI correctly reported the status of the CRM in 40 patients. Statistically, there was the best correlation between pathologic and radiologic reporting of CRM involvement (Kappa=0.829, P=0.000). Conclusion Preoperative highresolution MRI scans has a good concordance with pathologic tumor stage but common with pathologic lymph node stage. Preoperative highresolution MRI can provide reliable information about CRM and thus help to choose which patient could benefit from the preoperative neoadjuvant therapy.
Hemispheric asymmetry is a fundamental organizing principle of the human brain. Answering the genetic effects of the asymmetry is a prerequisite for elucidating developmental mechanisms of brain asymmetries. Multi-modal magnetic resonance imaging (MRI) has provided an important tool for comprehensively interpreting human brain asymmetry and its genetic mechanism. By combining MRI data, individual differences in brain structural asymmetry have been investigated with quantitative genetic brain mapping using gene-heritability. Twins provide a useful natural model for studying the effects of genetics and environment on the brain. Studies based on MRI have found that the asymmetry of human brain structure has a genetic basis. From the perspective of quantitative genetic analysis, this article reviews recent findings on the genetic effects of asymmetry and genetic covariance between hemispheres from three aspects: the asymmetry of heritability, the heritability of asymmetry and the genetic correlation. At last, the article shows the limitations and future research directions in this field. The purpose of this systematic review is to quickly guide researchers to understand the origins and genetic mechanism of interhemispheric differences, and provide a genetic basis for further understanding and exploring individual differences in laterized cognitive behavior.