三维时间飞跃法磁共振血管成像序列联合磁共振三维稳态进动快速成像对三叉神经痛的诊断价值

目的:探讨三维时间飞跃法磁共振血管成像(3D-TOF-MRA)序列联合磁共振三维稳态进动快速成像(3D-FIESTA)对三叉神经痛(TN)的诊断价值。方法:选取医院收治的86例TN患者,所有患者均行3D-TOF-MRA和3D-FIESTA检查,以显微血管减压术(MVD)为诊断“金标准”,评估3D-TOF-MRA、3D-FIESTA以及二者联合检查责任血管的阳性预测值及阴性预测值,采用受试者工作特征(ROC)曲线下面积(AUC)对比分析TN责任血管情况。结果:在86例TN患者中,经MVD确诊TN责任血管80例,未见TN责任血管6例,经3D-TOF-MRA检测TN责任血管阳性预测值和阴性预测值分别为94.59%和16.67%;经3D-FIESTA检测阳性预测值和阴性预测值分别为94.44%和14.29%;经3D-ToF-MRA联合3D-FIESTA检测分别为97.50%和66.67%。3D-TOF-MRA联合3D-FIESTA检测准确率及灵敏度均高于3D-TOF-MRA和3D-FIESTA单项检测,漏诊率低于3D-TOF-MRA和3D-FIESTA单项检测,差异有统计学意义(χ^(2)=8.401,χ^(2)=7.778,χ^(2)=7.778;P<0.05);3D-TOF-MRA联合3D-FIESTA检测误诊率低于3D-TOF-MRA和3D-FIESTA单项检测,而特异度高于3D-TOF-MRA和3D-FIESTA单项检测,但差异无统计学意义。3D-TOF-MRA、3D-FIESTA及两项联合诊断TN责任血管的AUC值分别为0.604、0.592和0.821。结论:3D-TOF-MRA联合3D-FIESTA在TN诊断中具有互补作用,既能明确责任血管的存在,又能明确其血管类型,对制定手术方案具有指导意义。

动态增强技术联合磁共振弥散加权成像技术诊断乳腺良恶性病变的临床价值

目的探讨动态增强(DCE-MRI)技术联合磁共振弥散加权成像(MR-DWI)技术诊断乳腺良恶性病变的临床效果。方法以2017年1月至2018年1月浙江大学舟山医院收治的乳腺发生病变患者100例为研究对象,对患者实施MR-DWI和DCE-MRI检查并与病理验证结果进行比较分析。结果良性乳腺病灶的表观扩散系数(ADC)值为(1.65±0.24)×10^-3mm^2/s;恶性乳腺病灶的ADC值为(1.17±0.17)×10^-3mm^2/s,良恶性病灶患者ADC值相比差异有统计学意义(t=5.021,P<0.05)。88例良性病灶患者Ⅰ型、Ⅱ型、Ⅲ型曲线病例数分别为62例(70.45%)、18例(20.45%)和8例(9.09%)。20例恶性病灶患者Ⅰ型、Ⅱ型、Ⅲ型曲线病例数分别为3例(15.00%)、5例(25.00%)和12例(60.00%)。对动态增强Ⅰ型和Ⅲ型曲线在乳腺良恶性病灶相比,差异有统计学意义(χ^2=8.254,P<0.05),两者联合诊断的曲线下面积与单纯使用ADC和DEC-MRI相比,差异有统计学意义(χ^2=6.032,P<0.05),ADC与DEC-MRI诊断的曲线下面积相比差异无统计学意义(χ^2=5.221,P>0.05)。结论综合运用DWI与DCE-MRI这两种方式之后,能够为乳腺恶性肿瘤的诊断奠定坚实的数据基础,并且有效强化诊断的敏感性与特异性,进而使得临床干预与临床治疗的进行更加容易。

Preliminary clinical application of total free-breathing cardiac MR examination

Objective To observe the clinical application value of total free-breathing cardiac MR(CMR)examination preliminarily.Methods Two patients who underwent CMR scanning under free-breathing state,including cine,motion correction T1 and T2 mapping,blood flow imaging,and late gadolinium enhancement scanning were retrospectively enrolled,and the qualities of the above images were evaluated and compared with that of conventional CMR images under breath-holding state.Results No significant difference of imaging quality was found between total free-breathing and conventional breath-holding CMR.The differences of left ventricular ejection fraction,cardiac output,left ventricular end-diastolic volume index and left ventricular mass measured based on CMR images under different breath conditions were limited.Conclusion Total free-breathing CMR was feasible in clinical practice,which could provide"one-stop"evaluation of cardiac structure,function and myocardial histological characteristics,hence having promising clinical prospects.

DWI和DCE-MRI定量评价食管癌放化疗疗效的应用

食管癌是我国消化系统常见恶性肿瘤,目前临床对食管癌疗效评估主要采用实体瘤疗效评价标准,由于治疗中和治疗后水肿的存在,常规影像学技术不能准确反映食管癌肿瘤实际变化情况,而功能成像则可以先于形态学反映肿瘤功能代谢的变化。近年来磁共振扩散加权成像(DWI)、磁共振动态对比增强(DCE)等功能成像用来定量评估肿瘤组织内水分子扩散和血流灌注渗透微循环的应用日渐增多且在评估肿瘤疗效的应用上也有了一定的进展。该文将对上述功能影像方法在食管癌疗效评估方面的应用现状和进展予以综述。

MOTOR CORTEX NETWORKS IN STROKE PATIENTS DURING RECOVERY WITH fMRI

To investigate changes of functional activation areas of the cerebral cortex and the connectivity of motor cortex networks （MCNs） in stroke patients during the recovery, five patients with the infarct in their left hemispheres are recruited. Functional magnetic resonance imaging （fMRI） is performed in the second, fourth, eighth, and sixteenth weeks after the stroke. Images are analyzed using the professional software SPM5 to obtain the bilateral activation of the motor cortex in left and right handgrip tests. MCN data are extracted from the active areas, and the structural and functional characteristic parameters are computed to indicate the connectivity of the network. Results show that the ipsilesional hemisphere recruits more areas with less active extent during the handgrip test, compared with the contralesional hemisphere. MCN shows a higher overall degree of statistical independence and more statistical dependence among motor areas with the gradual recovery. It can help physicians understand the recovery mechanism.

ARTIFACT CORRECTION OF RIGID TRANSLATIONAL MOTION IN MRI

During the process of magnetic resonance imaging （MRI）, the patient motion causes phase errors in collected signals and induces motion artifacts in the reconstructed image. Severe artifacts interfere with the focus location. Because the genetic algorithm （GA） has characteristics of parallel, random and adaptive stochastic searching, a correction method of motion artifacts is presented based on the algorithm. The method can correct the phase error in K-space signals step by step. Experiments show that the motion artifacts in MRI can be effectively suppressed by using the method.

Pancreatic carcinoma coexisting with chronic pancreatitis versus tumor-forming pancreatitis:Diagnostic utility of the time-signal intensity curve from dynamic contrast-enhanced MR imaging

AIM: To evaluate the ability of the time-signal intensity curve (TIC) of the pancreas obtained from dynamic contrast-enhanced magnetic resonance imaging (MRI) for differentiation of focal pancreatic masses, especially pancreatic carcinoma coexisting with chronic pancreatitis and tumor-forming pancreatitis. METHODS: Forty-eight consecutive patients who underwent surgery for a focal pancreatic mass, including pancreatic ductal carcinoma (n = 33), tumor-forming pancreatitis (n = 8), and islet cell tumor (n = 7), were reviewed. Five pancreatic carcinomas coexisted with longstanding chronic pancreatitis. The pancreatic TICs were obtained from the pancreatic mass and the pancreatic parenchyma both proximal and distal to the mass lesion in each patient, prior to surgery, and were classified into 4 types according to the time to a peak: 25 s and 1, 2, and 3 min after the bolus injection of contrast material, namely, type-Ⅰ, Ⅱ, Ⅲ, and Ⅳ, respectively, and were then compared to the corresponding histological pancreatic conditions. RESULTS: Pancreatic carcinomas demonstrated type-Ⅲ (n = 13) or Ⅳ (n = 20) TIC. Tumor-forming pancreatitis showed type-Ⅱ (n = 5) or Ⅲ (n = 3) TIC. All islet cell tumors revealed type-Ⅰ. The type-Ⅳ TIC was only recognized in pancreatic carcinoma, and the TIC of carcinoma always depicted the slowest rise to a peak among the 3 pancreatic TICs measured in each patient, even in patients with chronic pancreatitis.CONCLUSION: Pancreatic TIC from dynamic MRI provides reliable information for distinguishing pancreatic carcinoma from other pancreatic masses, and may enable us to avoid unnecessary pancreatic surgery and delays in making a correct diagnosis of pancreatic carcinoma, especially, in patients with longstanding chronic pancreatitis.

MAGNETIC RESONANCE IMAGING OF ACUTE CENTRAL CORD SYNDROME: CORRELATION WITH PROGNOSIS

Objective. To report the magnetic resonance imaging (MRI) findings of acute cervical central cord syndrome and to determine their correlation with the prognosis. Methods. MRI findings of 35 patients with acute central cord syndrome were studied and compared with the recovery rate of ASIA score at presentation and in follow- up. Results. MRI data demonstrated spinal cord compression for 32 patients, spinal cord swelling for 16 patients, and abnormal signal intensity within the spinal cord for 19 patients, including 14 with edema and 3 with hematoma. No significant difference of the recovery rate was noted between the patients treated nonoperatively and operatively (P >0.05). There was a significant inverse correlation between the recovery rate and the degree of spinal cord compression as shown in MRI scans (P< 0.01). The presence of hematoma in MRI scans was associated with poor prognosis, as demonstrated by a significant difference of the recovery rate (P< 0.01) among the patients with normal intensity, edema and hematoma within the spinal cord. Conclusions. MRI scans provide an efficient assistance for decision- making and accurate prognostic information regarding neurological function, and therefore should routinely be performed within the early phase of acute central cord syndrome.

BLOOD FLOW PATTERN AND QUANTITATIVE STUDY IN SOLITARY PULMONARY NODULES WITH DYNAMIC CONTRAST-ENHANCED MRI

Objective To evaluate the efficacy of contrast enhanced dynamic MRI in differentiating solitary pulmonary nodules（SPNs）. Methods Eighty-three patients with SPNs undertaken contrast enhanced dynamic MRI. Time-signal intensity curve （T-SI Curve） was made. Peak height （PH） , steepest slope （SS）, maximum enhancement （ Emax ） and the enhancement rates of signal intensity were recorded at the frst （ E1 ）, second （ E2 ）, third （ E3 ） , fourth （ E4 ） , fifth （E5）, and sixth （ E6 ） minute after injection. Results Malignant nodules and inflammatory nodules enhanced significantly higher than benign nodules, and malignant nodules and inflammatory nodules showed obviously higher PH, SS, Emax, El-E6 values than benign nodules （ P 〈 0. 01 ）. There were no sig- nificant differences in PH, SS, Emax, E1-E6 values between malignant nodules and inflammatory nodules （P 〉 0. 05）. Conclusion Contrast enhanced dynamic MR imaging can provide SPNs＇ hemodynamic information and is helpful in differentiating SPNs.

Obstacles Facing the Implementation of Functional Magnetic Resonance Imaging （fMRI） of Brain in Jeddah City

fMRI （Functional Magnetic Resonance Imaging） is a relatively new technique that uses MRI （Magnetic Resonance Imaging） to measure the hemodynamic response （change in blood flow） related to neural activity in the brain. This paper aims to explore and identify the obstacles facing the implementation and applications of IMRI in radiology departments within Jeddah city by analyzing related data received by direct questionnaires and interviews with all the people working in MRI units in Jeddah city and finds that the major obstacle is lacking of awareness of fMRI among medical professionals and their training.

MR IMAGING OF CORONARY ARTERY BYPASS GRAFT:A PRELIMINARY STUDY

Objective. To make a preliminary investigation of the patency and function of coronary artery bypass grafts(CABG) by magnetic resonance(MR) images and to establish a suitable method for followup study after CABG operation among Chinese. Methods. MR imaging was performed with a Toshiba 15T unit in 27 patients with 74 grafts. All patients were examined with a breathhold ECGgated twodimensional fast field echo (FFE) sequence to evaluate the patency of bypass grafts, among them 16 patients with 42 grafts were further examined with a phase shift magnetic resonance angiography flow (PSMRAflow) sequence to evaluate the grafts patency as well as the flow velocity and flow volume vs. time. Results. The results showed that 66 of the 74 grafts in the patients of the present series studied with FFE were patent with a patency rate of 892% The results evaluated both with FFE and PSMRAflow remained the same except that two grafts were patent with FFE and the results with PSMRAflow were uncertain. Diastolic perfusion pattern curves were found in 25 of the 32 grafts in patients of the present series. Comparing the flow curves of the grafted left internal mammary artery with those of the native right internal mammary artery in 7 patients, the systolic peak velocity value(SPV) of the grafted arteries was significantly lower than that of the ungrafted ones, whereas the diastolic peak velocity value(DPV) and the ratio of DPV to SPV were significantly greater than that of the ungrafed ones. Conclusion. The FFE and PSMRAflow sequences were efficient in evaluating patency and obtaining the curves of flow velocity and volume of the bypass grafts. Therefore, they may offer a noninvasive screening method for followup study in patients after CABG surgery, although its accuracy should be further evaluated in more patients and comparatively studied with other methods.

Research on resting spontaneous brain activity and functional connectivity of acupuncture at uterine acupoints

Objective The resting-state functional magnetic resonance imaging(rs-f MRI)method was used to observe brain activity and its functional connection upon electroacupuncture stimulation at bilateral uterine acupoints(EX-CA1),as well as to investigate the mechanism of acupuncture in the treatment of gynecological diseases.Methods Twenty-two healthy female subjects were stimulated by electroacupuncture at bilateral uterine acupoints;rs-f MRI data of the brain were acquired and standardized.Degree centrality(DC),amplitude of low-frequency fluctuation(ALFF),and regional homogeneity(ReHo)were used to analyze local spontaneous brain activity via acupuncture.An independent component analysis was used to evaluate the functional connectivity of the resting brain networks after acupuncture.Results Analytical results showed that the neural activity intensity of the precuneus lobe,orbitofrontal cortex,lingual gyrus,amygdala,and posterior central gyrus decreased after acupuncture(voxel P<0.001,cluster P<0.05).Functional connectivity analysis revealed weakened auditory and right frontal-parietal networks(voxel P<0.001,cluster P<0.05),enhanced visual network(voxel P<0.001,cluster P<0.05),and synergistic auditory network and hypothalamic-pituitary system.Conclusion Significant differences in neural activity and functional connectivity in specific brain regions were observed after acupuncture intervention at uterine acupoints;the hypothalamic-pituitary system also showed various active states in different brain regions.It is speculated that the effective mechanism of acupuncture at uterine acupoints is related to the regulation of reproductive hormones,emotional changes,and somatic sensations.Therefore,the methods used in this study could clarify the neural mechanism of uterine-point acupuncture in the treatment of gynecological diseases and may serve as a reference for other studies pertaining to acupuncture.

Quantitative assessment of acute kidney injury by noninvasive arterial spin labeling perfusion MRI:a pilot study

The kidneys are essential for maintaining homeostasis,are responsible for the reabsorption of water,glucose and amino acids,and filter the blood by removing waste.Acute kidney injury(AKI) is a syndrome characterized by the rapid loss of renal excretory function and the accumulation of end metabolic products of urea and creatinine.AKI is associated with the later development of chronic kidney disease and end-stage kidney disease,and may eventually be fatal.Early diagnosis of AKI and assessments of the effects of treatment,however,are challenging.The pathophysiological mechanism of AKI is thought to be the imbalance between oxygen supply and demand in the kidneys.We have assessed the ability of arterial spin labeling(ASL) perfusion magnetic resonance imaging(MRI),without the administration of contrast media,to quantify renal blood flow(RBF) non-invasively.We found that RBF was significantly lower in AKI patients than in healthy volunteers.These results suggest that ASL perfusion MRI,a noninvasive measurement of RBF,may be useful in the early diagnosis of AKI.

Janus γ-Fe2O3/SiO2-based nanotheranostics for dual-modal imaging and enhanced synergistic cancer starvation/chemodynamic therapy

Multimodal cancer synergistic therapy exhibited remarkable advantages over monotherapy in producing an improved therapeutic efficacy. In this work, Janus-type γ-Fe2 O3/SiO2 nanoparticles(JFSNs) are conjugated with glucose oxidase(GOx) for synergistic cancer starvation/chemodynamic therapy. The γ-Fe2O3 hemisphere of JFSNs can perform photoacoustic/T2 magnetic resonance dual-modal imaging of tumors.GOx on the surface of JFSNs catalyzes the decomposition of glucose and produces H2O2 for cancer starvation therapy. Subsequently, the γ-Fe2O3 hemisphere catalyzes the disproportionation of H2O2 to generate highly reactive hydroxyl radicals in an acidic tumor microenvironment. The close distance between GOx and JFSNs ensures adequate contact between the γ-Fe2O3 hemisphere and its substrate H2O2, thus enhancing the catalytic efficiency. This synergy of glucose depletion, biotoxic H2O2 and hydroxyl radicals significantly suppresses 4 T1 mammary tumor growth with minimal adverse effects.

Neural substrates of data-driven scientific discovery:An fMRI study during performance of number series completion task

Although much has been known about how humans psychologically perform data-driven scientific discovery,less has been known about its brain mechanism.The number series completion is a typical data-driven scientific discovery task,and has been demonstrated to possess the priming effect,which is attributed to the regularity identification and its subsequent extrapolation.In order to reduce the heterogeneities and make the experimental task proper for a brain imaging study,the number magnitude and arithmetic operation involved in number series completion tasks are further restricted.Behavioral performance in Experiment 1 shows the reliable priming effect for targets as expected.Then,a factorial design (the priming effect:prime vs.target;the period length:simple vs.complex) of event-related functional magnetic resonance imaging (fMRI) is used in Experiment 2 to examine the neural basis of data-driven scientific discovery.The fMRI results reveal a double dissociation of the left DLPFC (dorsolateral prefrontal cortex) and the left APFC (anterior prefrontal cortex) between the simple (period length=1) and the complex (period length=2) number series completion task.The priming effect in the left DLPFC is more significant for the simple task than for the complex task,while the priming effect in the left APFC is more significant for the complex task than for the simple task.The reliable double dissociation may suggest the different roles of the left DLPFC and left APFC in data-driven scientific discovery.The left DLPFC (BA 46) may play a crucial role in rule identification,while the left APFC (BA 10) may be related to mental set maintenance needed during rule identification and extrapolation.

Effects of Rosiglitazone on Rabbit Atherosclerosis

We sought to validate magnetic resonance imaging(MRI) for documenting the effects of rosiglitazone on rabbit atherosclerosis and the possible mechanism by treatment on the lesions.24 New Zealand white rabbits were randomly divided into normal group, control group and treatment group.After 4 weeks, all rabbits underwent MRI.After examination, the number of circulating endothelial progenitor cells(EPCs) and level of lipid, glucose, nitric oxide(NO) and superoxide anion(O-2·) were measured.MRI demonstrated the regression of atherosclerotic lesions by rosiglitazone which has good correlation with histopathology.Treatment not only increased the level of EPCs and NO, but also raised the ability of inhibition of O2-·.MRI is a promising noninvasive technology to detect the effects of therapeutic interventions.Rosiglitazone slows the progression of atherosclerosis that may in part attribute to its improvement of mobilization of EPCs and the reduced oxidative stress.

Brain activity in Parkinson's disease patients with mild cognitive impairment

Mild cognitive impairment （MCI） is common in patients with Parkinson＇s disease （PD）, yet the underlying neural mechanisms of this disease state remain unclear. We investigated alterations in the spontaneous brain activity of PD patients with MCI （PD-MCI） relative to cognitively normal PD patients （PD-CN） and healthy control （HC） subjects. In this work, 13 PD-MCI patients, 16 PD-CN patients, and 16 HC subjects completed resting state functional MRI. Spontaneous brain activity was measured by calculating amplitude of low frequency fluctuation （ALFF） values across the whole brain. Between-group differences and correlations between ALFF values and cognitive test scores were analyzed. ALFF values decreased in the right superior temporal gyrus and increased in the left middle temporal gyrus and left superior frontal gyms of PD-MCI patients compared with PD-CN patients. In the PD-MCI group, ALFF values in the left middle temporal gyrus were negatively correlated with Montreal Cognitive Assessment and vocabulary test scores, and the ALFF values in the left superior frontal gyms were negatively correlated with vocabulary test scores. Our study demonstrates that PD-MCI is associated with abnormal spontaneous brain activity in the temporal and frontal lobes. These findings inform the underlying neural mechanism of cognitive impairment in PD.

Magnetic Resonance Imaging of Atherosclerotic Lesion with New Devised Animal Surface Coil

The ability of dynamic contrast enhanced magnetic resonance imaging(DCE MRI) with a new devised animal surface coil was analyzed in identifying atherosclerotic plaques in the rabbit medium-sized iliac artery(IA).Then a comparative analysis of multi-detector computed tomography(MDCT) and DCE MRI was done in discerning morphology and components of 80 atherosclerotic plaques identified by histopathology.It shows that the DCE MRI may be an emerging noninvasive and economic way to characterize atherosclerotic plaques at present.What's more, a new devised animal surface coil would further improve the signal-to-noise ratio(SNR) and the quality of imaging.However, CT angiography(CTA) may be better than MR angiography(MRA) in detecting vessel stenosis.

Correlation of MR imaging and histopathology after partial resection of normal rabbit brain

Abstract Objectives To investigate the findings of magnetic resonance (MR) imaging and histopathology in early postoperative normal brain, and to define the correlation between MR images and histopathology. Methods Thirty-six New Zealand rabbits weighing 2.0 to 3.0*!kg were divided into 10 groups according to different postoperative days: 1 to 10 days. A partial resection of the parietooccipital region was performed under usual aseptic conditions after the animals were anesthetized intravenously with 3% pentobarbital (30*!mg/kg). MR imaging procedures consisted of pre- and postcontrast scanning and were carried out on postoperative days 1 to 10. Brain tissue samples were prepared for examination immediately after MR scanning. Histopathological examination was done under light both and electron microscopes. The findings of MR imaging were compared with histopathologic findings.Results Surgical margin contrast enhancement on MR images could be seen 24 hours after surgery. The degree of contrast enhancement increased gradually up to 5 days postoperation, and no remarkable changes were present from days 5 to 10. Disruption of the blood brain barrier (BBB) was the main cause of contrast enhancement during the first 3 postoperative days. After that period, the mechanism responsible for contrast enhancement was the formation of neovascularity and a broken BBB. An increase in the amount of neovascularity played a predominant role in contrast enhancement in normal postoperative brain tissue. Conclusions The features of enhanced MR images present at the surgical margin followed a typical time course during the early postoperative period. The role of neovascularity and BBB disruption in the formation of contrast enhancement at the surgical margin varies with time. Knowledge of the features of contrast enhancement in postoperative MR images of normal brain can help in differentiating benign changes from residual malignant glioma.