Validation of hyperintense middle cerebral artery sign in acute ischemic stroke Comparison between magnetic resonance imaging and angiography

We performed a retrospective analysis of non-contrast computed tomography （CT） scans, immediately subsequent magnetic resonance imaging （MRI）, and cerebral angiography data from 30 consecutive patients with acute ischemic stroke within 6 hours after symptom onset. Results showed that eleven patients developed subsequent hemorrhagic transformation at follow-up. A hyperintense middle cerebral artery sign on MRI was found in six hemorrhagic patients, all of who had acute thrombosis formation on magnetic resonance angiography and digital subtraction angiography. No patients in the non-hemorrhagic group had hyperintense middle cerebral artery sign on MRI. The sensitivity, specificity, and positive predictive values of the hyperintense middle cerebral artery sign on MRI T1-weighted image for subsequent hemorrhagic transformation were 54.5%, 100%, and 100% respectively. Hyperdense middle cerebral artery sign on non-contrast CT was observed in nine patients, five of who developed hemorrhagic transformation. These data suggest that hyperintense middle cerebral artery sign on MRI T1-weighted image is a highly specific and moderately sensitive indicator of subsequent hemorrhagic transformation in patients after acute ischemic stroke, and its specificity is superior to CT.

Three-dimensional time-of-flight magnetic resonance angiography combined with high resolution T2-weighted imaging in preoperative evaluation of microvascular decompression

BACKGROUND Neurovascular compression(NVC) is the main cause of primary trigeminal neuralgia(TN) and hemifacial spasm(HFS). Microvascular decompression(MVD) is an effective surgical method for the treatment of TN and HFS caused by NVC. The judgement of NVC is a critical step in the preoperative evaluation of MVD, which is related to the effect of MVD treatment. Magnetic resonance imaging(MRI) technology has been used to detect NVC prior to MVD for several years. Among many MRI sequences, three-dimensional time-of-flight magnetic resonance angiography(3D TOF MRA) is the most widely used. However, 3D TOF MRA has some shortcomings in detecting NVC. Therefore, 3D TOF MRA combined with high resolution T2-weighted imaging(HR T2WI) is considered to be a more effective method to detect NVC.AIM To determine the value of 3D TOF MRA combined with HR T2WI in the judgment of NVC, and thus to assess its value in the preoperative evaluation of MVD.METHODS Related studies published from inception to September 2022 based on PubMed, Embase, Web of Science, and the Cochrane Library were retrieved. Studies that investigated 3D TOF MRA combined with HR T2WI to judge NVC in patients with TN or HFS were included according to the inclusion criteria. Studies without complete data or not relevant to the research topics were excluded. The Quality Assessment of Diagnostic Accuracy Studies checklist was used to assess the quality of included studies. The publication bias of the included literature was examined by Deeks’ test. An exact binomial rendition of the bivariate mixed-effects regression model was used to synthesize data. Data analysis was performed using the MIDAS module of statistical software Stata 16.0. Two independent investigators extracted patient and study characteristics, and discrepancies were resolved by consensus. Individual and pooled sensitivities and specificities were calculated. The I_(2) statistic and Q test were used to test heterogeneity. The study was registered on the website of PROSERO(registration No. CRD42022357158).RESULTS Our search identified 595 articles, of which 12(including 855 patients) fulfilled the inclusion criteria. Bivariate analysis showed that the pooled sensitivity and specificity of 3D TOF MRA combined with HR T2WI for detecting NVC were 0.96 [95% confidence interval(CI): 0.92-0.98] and 0.92(95%CI: 0.74-0.98), respectively. The pooled positive likelihood ratio was 12.4(95%CI: 3.2-47.8), pooled negative likelihood ratio was 0.04(95%CI: 0.02-0.09), and pooled diagnostic odds ratio was 283(95%CI: 50-1620). The area under the receiver operating characteristic curve was 0.98(95%CI: 0.97-0.99). The studies showed no substantial heterogeneity(I2 = 0, Q = 0.001 P = 0.50).CONCLUSION Our results suggest that 3D TOF MRA combined with HR T2WI has excellent sensitivity and specificity for judging NVC in patients with TN or HFS. This method can be used as an effective tool for preoperative evaluation of MVD.

In vivo tracking of human adipose-derived stem cells labeled with ferumoxytol in rats with middle cerebral artery occlusion by magnetic resonance imaging

Ferumoxytol, an iron replacement product, is a new type of superparamagnetic iron oxide ap- proved by the US Food and Drug Administration. Herein, we assessed the feasibility of tracking transplanted human adipose-derived stem cells labeled with ferumoxytol in middle cerebral artery occlusion-injured rats by 3.0 T MRI in vivo. 1 × 104 human adipose-derived stem cells labeled with ferumoxytol-heparin-protamine were transplanted into the brains of rats with middle cerebral artery occlusion. Neurologic impairment was scored at 1, 7, 14, and 28 days after transplantation. T2-weighted imaging and enhanced susceptibility-weighted angiography were used to observe transplanted cells. Results of imaging tests were compared with results of Prussian blue staining. The modified neurologic impairment scores were significantly lower in rats transplanted with cells at all time points except I day post-transplantation compared with rats without transplantation. Regions with hypointense signals on T2-weighted and enhanced susceptibility-weighted angiography images corresponded with areas stained by Prussian blue, suggesting the presence of superparamagnetic iron oxide particles within the engrafted cells. Enhanced susceptibility-weighted angiography image exhibited better sensitivity and contrast in tracing ferumoxytol-heparin-protamine-labeled human adipose-derived stem ceils compared with T2-weighted imaging in routine MRI.

Comparison of 16 slice multi-detector computed tomography and breath hold 3D magnetic resonance angiography in the detection of coronary stenosis

Objective To compare 16-slice multi-detector spiral computed tomography (MDCT) and breathhold 3D magnetic resonance (MR) coronary angiography in the visualization of coronary arteries and the accuracy of detecting significant (＞ 50%) coronary stenoses in patients with suspected coronary artery disease. Methods Forty patients were examined by 16-slice CT (GE, Lightspeedl6)and MR (GE,Twinspeed) within 3 days; 31 of them underwent conventional coronary angiography (CAG) within 2 weeks after CT and MR scan. CT was performed with 16× 1.25 mm detector collimation, 0.5 s rotation time and images were reconstructed at 60%-75% of the cardiac cycle. MR was performed with breath hold 3D FIESTA (TR4.0 ms, TE1.7 ms, flip angle 65, slice thickness 3 mm, FOV 280 mm, matrix 256× 192). Mean heart rate was 63 ± 5.8 bpm and β-blocker was used in 24 patients. MR and CT image quality was evaluated in 9 coronary segments (RCA1, RCA2, RCA3, LM, LAD1, LAD2, LAD3, LCX1, LCX2) using a four-point grading scale.Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated for detection of significant stenosis using CAG as the gold standard. Results 16-slice CT showed higher image quality in most coronary segments except RCA2.Forty-three segments were diagnosed as significant stenosis by CAG, 36 and 27 of these were correctly detected by CT and MR respectively. Sensitivity, specificity, positive predictive value, and negative predictive value of 16-slice CT and MR for detecting significant stenosis were 83 %, 84 %, 49 %, 97 % and 63 %, 90 %, 55 %, 93 %, respectively. Conclusion Sixteen-slice CT showed higher image quality in most coronary segments excepted for middle RCA. 16-slice CT had higher sensitivity than MR for detection of coronary significant stenosis, whereas MR had higher specificity than CT. Both CT and MR showed high negative predictive value,which is useful for excluding coronary stenosis in symptomatic patients.

Application of MAGnetic resonance imaging compilation in acute ischemic stroke

BACKGROUND Synthetic magnetic resonance imaging(MRI)MAGnetic resonance imaging compilation(MAGiC)is a new MRI technology.Conventional T1,T2,T2-fluidattenuated inversion recovery(FLAIR)contrast images,quantitative images of T1 and T2 mapping,and MAGiC phase sensitive inversion recovery(PSIR)Vessel cerebrovascular images can be obtained simultaneously through post-processing at the same time after completing a scan.In recent years,studies have reported that MAGiC can be applied to patients with acute ischemic stroke.We hypothesized that the synthetic MRI vascular screening scheme can evaluate the degree of cerebral artery stenosis in patients with acute ischemic stroke.AIM To explore the application value of vascular images obtained by synthetic MRI in diagnosing acute ischemic stroke.METHODS A total of 64 patients with acute ischemic stroke were selected and examined by MRI in the current retrospective cohort study.The scanning sequences included traditional T1,T2,and T2-FLAIR,three-dimensional time-of-flight magnetic resonance angiography(3D TOF MRA),diffusion-weighted imaging(DWI),and synthetic MRI.Conventional contrast images(T1,T2,and T2-FLAIR)and intracranial vessel images(MAGiC PSIR Vessel]were automatically reconstructed using synthetic MRI raw data.The contrast-to-noise ratio(CNR)values of traditional T1,T2,and T2-FLAIR images and MAGiC reconstructed T1,T2,and T2-FLAIR images in DWI diffusion restriction areas were measured and compared.MAGiC PSIR Vessel and TOF MRA images were used to measure and calculate the stenosis degree of bilateral middle cerebral artery stenosis areas.The consistency of MAGiC PSIR Vessel and TOF MRA in displaying the degree of vascular stenosis with computed tomography angiography(CTA)was compared.RESULTS Among the 64 patients with acute ischemic stroke,79 vascular stenosis areas showed that the correlation between MAGiC PSIR Vessel and CTA(r=0.90,P<0.01)was higher than that between TOF MRA and CTA(r=0.84,P<0.01).With a degree of vascular stenosis>50%assessed by CTA as a reference,the area under the receiver operating characteristic(ROC)curve of MAGiC PSIR Vessel[area under the curve(AUC)=0.906,P<0.01]was higher than that of TOF MRA(AUC=0.790,P<0.01).Among the 64 patients with acute ischemic stroke,39 were scanned for traditional T1,T2,and T2-FLAIR images and MAGiC images simultaneously,and CNR values in DWI diffusion restriction areas were measured,which were:Traditional T2=21.2,traditional T1=-6.7,and traditional T2-FLAIR=11.9;and MAGiC T2=7.1,MAGiC T1=-3.9,and MAGiC T2-FLAIR=4.5.CONCLUSION The synthetic MRI vascular screening scheme for patients with acute ischemic stroke can accurately evaluate the degree of bilateral middle cerebral artery stenosis,which is of great significance to early thrombolytic interventional therapy and improving patients’quality of life.

Modified magnetic resonance angiography of the liver using sensitivity encoding in comparison with digital subtraction angiography and CT arterial portography

BACKGROUND: Over 355 patients have received ortho- topic liver transplantation ( OLT) at this hospital since 1993. Preoperative imaging studies of both hepatic vessels and parenchyma in these recipients bettered surgical plan- ning or even precluded the necessity of surgery. Here we report our preliminary results of modified magnetic reso- nance angiography ( MRA ) using sensitivity encoding ( SENSE) through comparative study with conventional digital subtraction angiography (DSA) and CT arterial por- tography (CTAP). METHODS: Sixteen patients with suspected liver diseases were included in the study. All of them received both dy- namic MRI of the liver using SENSE and digital DSA with CTAP within a two-week interval. The four-phase MRA was reconstructed from source images of the coronal dy- namic study. The arterial phase of the modified MRA was compared with DSA in the evaluation of hepatic arteries and the portal phase compared with CT portography recon- structed from source images of CTAP. In dynamic study of the liver, a fixed dose (20 ml) of contrast medium and scan timing were used. RESULTS: The main branches and variations of the hepatic arterial system were well shown on the modified MRA, al- though the marginal branches of hepatic arteries were of poor quality. The figures of portal veins on MRA were as clear as or superior to those of CTAP. In addition, the su- prarenal inferior vena cava (IVC) was well demonstrated on MRA and/or non contrast-enhanced coronal balanced fast-field echo (b-FFE) scan sequence in most cases. MRI detected most parenchymal lesions of the liver and hemo- dynamics of these lesions could be evaluated on source ima- ges of the modified MRA. MRI/MRA also serendipitously revealed several extrahepatic disease entities or variations that were not found on DSA/CTAP. CONCLUSIONS: The modified MRA using SENSE is a cost-effective modality of examination for the demonstra- tion of the whole hepatic vascular system. Combined with MRI, it has the potential as a one-stop imaging modality in the preoperative evaluation in fields such as OLT.

Magnetic Resonance Imaging of Coronary Arteries:Latest Technical Innovations and Clinical Experiences

Cardiovascular disease(CVD)is the leading cause of death and a major health care challenge globally.Coronary artery disease(CAD)is a primary underlying pathological process in the majority of cardiovascular disease cases.Magnetic resonance imaging(MRI)can play a potentially important role in the management of CAD as a noninvasive imaging modality without ionizing radiation,although its early promise has not been delivered because of several crucial technical limitations.However,recent innovations in MRI have reopened the door,with tremendous opportunities for multiparametric assessment of CAD including luminal stenosis,plaque burden and composition,and disease activities such as infl ammation and hemorrhage.Novel MRI acquisition and reconstruction strategies now offer much increased spatial resolution and image quality and shortened examination times compared with conventional approaches.Recent clinical experiences of coronary MRI indicated the potential to improve the current management of coronary atherosclerosis,such as identifying the patients at the highest risk and evaluating therapeutic responses.In this review we discuss the latest technical advances and clinical insights in coronary MRI.

Diffusion-weighted magnetic resonance imaging in cancer: Reported apparent diffusion coefficients,in-vitro and invivo reproducibility

There is considerable disparity in the published apparent diffusion coefficient(ADC) values across different anatomies. Institutions are increasingly assessing repeatability and reproducibility of the derived ADC to determine its variation,which could potentially be used as an indicator in determining tumour aggressiveness or assessing tumour response. In this manuscript,a review of selected articles published to date in healthy extracranial body diffusion-weighted magnetic resonance imaging is presented,detailing reported ADC values and discussing their variation across different studies. In total 115 studies were selected including 28 for liver parenchyma,15 for kidney(renal parenchyma),14 for spleen,13 for pancreatic body,6 for gallbladder,13 for prostate,13 for uterus(endometrium,myometrium,cervix) and 13 for fibroglandular breast tissue. Median ADC values in selected studies were found to be 1.28 × 10-3 mm2/s in liver,1.94 × 10-3 mm2/s in kidney,1.60 × 10-3 mm2/s in pancreatic body,0.85 × 10-3 mm2/s in spleen,2.73 × 10-3 mm2/s in gallbladder,1.64 × 10-3 mm2/s and 1.31 × 10-3 mm2/s in prostate peripheral zone and central gland respectively(combined median value of 1.54×10-3 mm2/s),1.44 × 10-3 mm2/s in endometrium,1.53 × 10-3 mm2/s in myometrium,1.71 × 10-3 mm2/s in cervix and 1.92 × 10-3 mm2/s in breast. In addition,six phantom studies and thirteen in vivo studies were summarized to compare repeatability and reproducibility of the measured ADC. All selected phantom studies demonstrated lower intra-scanner and inter-scanner variation compared to in vivo studies. Based on the findings of this manuscript,it is recommended that protocols need to be optimised for the body part studied and that system-induced variability must be established using a standardized phantom in any clinical study. Reproducibility of the measured ADC must also be assessed in a volunteer population,as variations are far more significant in vivo compared with phantom studies.

Optimized Three-Dimensional Cardiovascular Magnetic Resonance Whole Heart Imaging Utilizing Non-Selective Excitation and Compressed Sensing in Children and Adults with Congenital Heart Disease

Background:In congenital heart disease(CHD)patients,detailed three-dimensional anatomy depiction plays a pivotal role for diagnosis and therapeutical decision making.Hence,the present study investigated the applicability of an advanced cardiovascular magnetic resonance(CMR)whole heart imaging approach utilizing nonselective excitation and compressed sensing for anatomical assessment and interventional guidance of CHD patients in comparison to conventional dynamic CMR angiography.Methods:86 consecutive pediatric patients and adults with congenital heart disease(age,1 to 74 years;mean,35 years)underwent CMR imaging including a freebreathing,ECG-triggered 3D nonselective SSFP whole heart acquisition using compressed SENSE(nsWHcs).Anatomical assessability and signal intensity ratio(SIR)measurements were compared with conventional dynamic 3D-/4D-MR angiography.Results:The most frequent diagnoses were partial anomalous pulmonary venous drainage(17/86,20%),transposition of the great arteries(15/86,17%),tetralogy of Fallot(12/86,14%),and a single ventricle(7/86,8%).Image quality of nsWHcs was rated as excellent/good in 98%of patients.nsWHcs resulted in a reliable depiction of all large thoracic vessels(anatomic assessability,99%–100%)and the proximal segments of coronary arteries and coronary sinus(>90%).nsWHcs achieved a homogenously distributed SIR in all cardiac cavities and thoracic vessels without a significant difference between pulmonary and systemic circulation(10.9±3.5 and 10.6±3.4;p=0.15),while 3D angiography showed significantly increased SIR for targeted vs.non-targeted circulation(PA-angiography,15.2±8.1 vs.5.8±3.6,p<0.001;PV-angiography,7.0±3.9 vs.17.3±6.8,p<0.001).Conclusions:The proposed nsWHcs imaging approach provided a consistently high image quality and a homogeneous signal intensity distribution within the pulmonary and systemic circulation in pediatric patients and adults with a wide spectrum of congenital heart diseases.nsWHcs enabled detailed anatomical assessment and three-dimensional reconstruction of all cardiac cavities and large thoracic vessels and can be regarded particularly useful for preprocedural planning and interventional guidance in CHD patients.

Role of pulmonary perfusion magnetic resonance imaging for the diagnosis of pulmonary hypertension:A review

Among five types of pulmonary hypertension,chronic thromboembolic pulmonary hypertension(CTEPH)is the only curable form,but prompt and accurate diagnosis can be challenging.Computed tomography and nuclear medicine-based techniques are standard imaging modalities to non-invasively diagnose CTEPH,however these are limited by radiation exposure,subjective qualitative bias,and lack of cardiac functional assessment.This review aims to assess the methodology,diagnostic accuracy of pulmonary perfusion imaging in the current literature and discuss its advantages,limitations and future research scope.

Contribution of cardiovascular magnetic resonance in the evaluation of coronary arteries

Cardiovascular magnetic resonance(CMR) allows the nonradiating assessment of coronary arteries; to achieve better image quality cardiorespiratory artefacts should be corrected. Coronary MRA(CMRA) at the mo-ment is indicated only for the detection of abnormal coronary origin, coronary artery ectasia and/or aneu-rysms(class Ⅰ indication) and coronary bypass grafts(class Ⅱ indication). CMRA utilisation for coronary ar-tery disease is not yet part of clinical routine. However, the lack of radiation is of special value for the coronary artery evaluation in children and women. CMRA can assess the proximal part of coronary arteries in almost all cases. The best results have been observed in the evaluation of the left anterior descending and the right coronary artery, while the left circumflex, which is lo-cated far away from the coil elements, is frequently im-aged with reduced quality, compared to the other two. Different studies detected an increase in wall thickness of the coronaries in patients with type Ⅰ diabetes and abnormal renal function. Additionally, the non-contrast enhanced T1-weighed images detected the presence of thrombus in acute myocardial infarction. New tech-niques using delayed gadolinium enhanced imaging promise the direct visualization of inflamed plaques in the coronary arteries. The major advantage of CMRis the potential of an integrated protocol offering as-sessment of coronary artery anatomy, cardiac function, inflammation and stress perfusion-fibrosis in the same study, providing an individualized clinical profile of pa-tients with heart disease.

Preliminary clinical application using 3D time-resolved imaging of contrast-enhanced MR angiography of contrast kinetics （3D-TRICKS）i

Objective：To introduce a new better contrast-enhanced MR angiographic metnod, named 3D time-resolved imaging of contrast kinetics （3D-TRICKS）. Methods： TRICKS is a high temporal resolution （2-6 s） MR angiographic technique using a short TR（4 ms） and TE（1.5 ms）, partial echo sampling, in which central part of k-space is updated more frequently than the peripheral part. TRICKS pre-contrast mask 3D images are firstly scanned, and then the bolus injecting of Gd-DTPA, 15-20 sequential 3D images are acquired. The reconstructed 3D images, subtraction of contrast 3D images with mask images, are conceptually similar to a catheter-based intra-arterial digital subtraction angiographic series （DSA）. Thirty patients underwent contrast-enhanced MR angiography using 3D-TRICKS. Results： Totally 12 vertebral arteries were well displayed on TRICKS, in which 7 were normal, 1 demonstrated bilateral vertebral artery stenosis, 4 had unilateral vertebral artery stenosis and 1 was accompanied with the same lateral carotid artery bifurcation stenosis. Four cases of bilateral renal arteries were normal, 1 transplanted kidney artery showed as normal and 1 transplanted kidney artery showed stenosis. 2 cerebral arteries were normal, 1 had sagittal sinus thrombosis and 1 displayed intracranial arteriovenous malformation. 3 pulmonary arteries were normal, 1 showed pulmonary artery thrombosis and 1 revealed pulmonary sequestration＇s abnormal feeding artery and draining vein. One left lower limb fibrolipoma showed feeding artery. One displayed radial-ulnar artery artificial fistula stenosis. One revealed left antebrachium hemangioma. Conclusion： TRICKS can clearly delineate most body vascular system and reveal most vascular abnormality. It possesses convenience and high successful rate, which make it the first choice of displaying most vascular abnormality.

Isotropic volumetric MRI for displaying cranial perineural spread of cranial nerve in nasopharyngeal carcinoma

Objective To observe the value of isotropic volumetric MRI for displaying perineural spread(PNS)of cranial nerve(CN)in nasopharyngeal carcinoma.Methods Eighty-seven patients with pathologically proven nasopharyngeal carcinoma were prospectively enrolled.MR scanning,including three-dimensional liver acquisition with volume acceleration-flexible(3D LAVA_Flex)image,T2WI with fat suppression(T2WI-FS),T1WI,contrast enhancement(CE)T1WI-FS of nasopharynx and neck region were performed.The displaying rates of CN PNS were evaluated and compared between 3D LAVA_Flex and T2WI-FS,T1WI,CE-T1WI-FS at patient level,CN group level and neural level,respectively.Results The displaying rate of CN PNS in all 87 nasopharyngeal carcinoma patients by 3D LAVA_Flex sequence was 49.43%(43/87),higher than that of conventional MRI(30/87,34.48%,P=0.001).Among 59 patients with advanced nasopharyngeal carcinoma diagnosed with conventional sequences,the displaying rate of CN PNS was 71.19%(42/59)by 3D LAVA-Flex sequence,higher than that of conventional MRI(30/59,50.85%,P=0.001).At both patient level and posterior CN level,significant differences of the displaying rate of CN PNS were found between 3D LAVA-Flex sequence and T2WI-FS,T1WI,CE-T1WI-FS,while at CN level,the displaying rates of mandibular nerve PNS,CNⅨ—ⅪPNS in jugular foramen(P<0.05)and CNⅨ—ⅫPNS in carotid space of 3D LAVA_Flex sequence were all significantly higher than that of T2WI-FS,T1WI and CE-T1WI-FS(all P<0.05),of PNS of CNⅢ—Ⅴin cavernous sinus were higher than that of T2WI-FS(P<0.05),while of PNS of hypoglossal nerve were significantly higher than that of T2WI-FS and T1WI(both P<0.05).Conclusion 3D LAVA_Flex sequence could be used to effectively display CN PNS of nasopharyngeal carcinoma.

三叉神经责任血管MRTA扫描序列的优化

目的探讨应用磁共振断层血管成像(MRTA)技术诊断三叉神经责任血管时对于扫描序列的优化。方法对32例临床诊断为三叉神经痛的患者行MRTA,采用三维时间飞跃法扰相梯度回波(3D-TOF FLASH)与容积内插屏气检查(VIBE)的大体素和小体素模式扫描,分析比较其图像质量。结果 VIBE序列图像所显示的三叉神经周围血管数目多于3D-TOF FLASH序列。大、小体素VIBE序列图像与大、小体素3D-TOF FLASH序列图像显示三叉神经周围血管的差异有统计学意义(P均<0.05)。VIBE序列图像的SNR与CNR均显著高于3D-TOF FLASH序列(P<0.05)。两种扫描序列中,应用大体素扫描模式获得图像的SNR与CNR均显著高于小体素扫描模式(P均<0.05)。结论应用MR-TA检查三叉神经时,采用大体素3D-TOF FLASH序列大范围扫描,能够准确、快速地辨认责任动脉血管,小范围内采用小体素VIBE序列能够精确显示脑桥小脑角池内三叉神经与邻近血管的关系。

MRTA诊断原发性面肌痉挛的临床价值

目的讨磁共振断层血管成像(MRTA)在原发性面肌痉挛(EHFS)临床诊断中的价值。方法收集36例面肌痉挛患者术前行MRTA检查,了解责任血管的来源及走向。结果 36例共72侧面神经,MRTA检查发现非症状侧血管压迫或接触4例,阳性率11%,而症状侧血管压迫或接触27例,阳性率75%,两者差异有统计学意义(P<0.001)。结论血管明确接触或压迫面神经征象与临床发生EHFS症状之间有密切关系,对微血管减压治疗面肌痉挛有重要的术前指导价值。

Three-dimensional-fast imaging employing steady-state acquisition and T2-weighted fast spin-echo magnetic resonance sequences on visualization of cranial nerves Ⅲ-Ⅻ

Because of the small diameter and complex anatomic course of the cranial nerves except for the optic nerve, trigeminal nerve, facial nerve, and cochlear and vestibular nerve, other cranial nerves are difficult to be visualized in magnetic resonance imaging （MRI） scanning with conventional thickness （5-10 mm）. With the rapid development of MRI technology high spatial resolution, three-dimensional and two-dimensional magnetic resonance imaging technologies have been used in recent years in the observation of normal and abnormal cranial nerves, including three-dimensional constructive interference in steady state （3D CISS） sequence, three- dimensional magnetization-prepared rapid gradient-echo （3D MP-RAGE） sequence, three-dimensional fast inflow with steady-state precession （3D FISP） seohuence, and some fast spin-echo （FSE） sequences. - Threedimensional fast imaging employing steady-state acquisition （3D-FIESTA） is a fast three-dimensional steady-state imaging sequence with high spatial resolution and contrast between the organizational structures. And this sequence was reportedly used in the study on the diseases in the cerebellopontine angle; inner ear and posterior fossa tumors.7＇8 However, the reports about the value of 3D-FIESTA sequence for the visualization of normal cranial nerves are still rare.

Neuroimaging diagnosis for cerebral infarction An 8-year bibliometric analysis

OBJECTIVE： To identify global research trends in neuroimaging diagnosis for cerebral infarction using a bibliometric analysis of the Web of Science. DATA RETRIEVAL： We performed a bibliometric analysis of data retrieval for neuroimaging diagnosis for cerebral infarction containing the key words ＂CT, magnetic resonance imaging, MRI, transcranial Doppler, transvaginal color Doppler, digital subtraction angiography, and cerebral infarction＂ using the Web of Science. SELECTION CRITERIA： Inclusion criteria were： （a） peer-reviewed articles on neuroimaging diagnosis for cerebral infarction which were published and indexed in the Web of Science; （b） original research articles and reviews; and （c） publication between 2004-2011. Exclusion criteria were： （a） articles that required manual searching or telephone access; and （b） corrected papers or book chapters. MAIN OUTCOME MEASURES： （1）Annual publication output; （2） distribution according to country; （3） distribution according to institution; （4） top cited publications; （5） distribution according to journals; and （6） comparison of study results on neuroimaging diagnosis for cerebral infarction. RESULTS： Imaging has become the predominant method used in diagnosing cerebral infarction. The most frequently used clinical imaging methods were digital subtraction angiography, CT, MRI, and transcranial color Doppler examination. Digital subtraction angiography is used as the gold standard. However, it is a costly and time-consuming invasive diagnosis that requires some radiation exposure, and is poorly accepted by patients. As such, it is mostly adopted in interventional therapy in the clinic. CT is now accepted as a rapid, simple, and reliable non-invasive method for use in diagnosis of cerebrovascular disease and preoperative appraisal. Ultrasonic Doppler can be used to reflect the hardness of the vascular wall and the nature of the plaque more clearly than CT and MRI. CONCLUSION： At present, there is no unified standard of classification of cerebral infarction imaging. Detection of clinical super-acute cerebral infarction remains controversial due to its changes on imaging, lack of specificity, and its similarity to a space-occupying lesion. Neuroimaging diagnosis for cerebral infarction remains a highly active area of research and development.

Pulmonary Sequestration: Three Dimensional Dynamic Contrast-enhanced MR Angiography and MRI

In order to evaluate the diagnostic value of three dimentional contrast enhanced MR angiography and MRI for pulmonary sequestration, 5 patients with pulmonary sequestration underwent 3D fast imaging by steady state precession (FISP) with a contrast medium and breath holding following chest radiography, CT and MR scans. The reconstructed MR angiography was performed using maximum intensity projection (MIP) and multiplanar reconstruction (MPR) techniques. It was found that the chest radiography showed pulmonary sequestration as a persistent area of opacity in the posterior basal segment of the left lower lobe, which was close to mediastinum in 2 cases and close to diaphragma in 3 cases. CT revealed a soft issue mass beyond descending aorta and lobar emphysema around the pulmonary sequestration. And the supplying vessel was documented in 2 cases on enhanced CT. MRI demonstrated a hyperintensity mass with respect to normal lung parenchyma on T1WI and T2WI, and the origin of the supplying vessel in 3 cases. The reconstructed CE MRA using MIP or MRP techniques clearly showed the supplying vessel and its course, branches as well as draining vessels. It was concluded that 3D CE MRA of demonstrating the supplying and draining vessels to pulmonary sequestration, together with plain MRI, can provide a diagnosis and aid in surgical planning without the need for DSA.

Magnetic resonance imaging and magnetic resonance angiography in severe crush syndrome with consideration of fasciotomy or amputation： a novel diagnostic tool

Three cases of severe crush syndrome after the Wenchuan earthquake in China are presented. The patients, 2 males and one female ranging in age from 18-45 years were studied via 1.5 T magnetic resonance imaging （MRI） and magnetic resonance angiography （MRA）. MRI examinations were performed more than twice on two patients within 60 days of the earthquake. All the patients had acute renal failure （ARF） with plasma myoglobin concentrations above 17 000 pg/L. The T2-weighted and short time inversion recovery （STIR） sequences revealed high intensity lesions in the affected muscles, and enhanced Tl-weighted images showed enhancement of partial affected muscles. MRA revealed no signs of arterial occlusion, artedostenosis, or filling defects of main arteries. All patients were managed medically with continuous venous-venous hemofiltration and other supportive care, and none required fasciotomy or amputation. Repeat MR studies showed that the high intensity lesions seen on the T2-weighted and STIR sequences resolved in parallel with improvement of laboratory studies and clinical course.

Clinical and Imaging Analysis of a Cerebellar Watershed Infarction

Objective: To investigate the characteristics of vascular lesions in patients with a cerebellar watershed infarction. Methods: Clinical data from 178 cases of cerebellar infarction were collected with magnetic resonance imaging (MRI) scan results, including diffusion weighted imaging (DWI), a magnetic resonance angiography (MRA), and computed tomography angiography (CTA). The cases were divided into cerebellar watershed and non-watershed infarctions based on lesion location, which was revealed by DWI. Forty-two cases met the criteria for a cerebellar watershed infarction. Based on the MRA/CTA results, the vertebrobasilar artery stenoses were divided into four categories (i.e., intracranial, extracranial, combined, and no detectable stenosis) to compare the vascular lesion characteristics from patients with a cerebellar watershed infarction and patients with a non-watershed infarction. Results: Patients with cerebellar watershed infarcts presented mild symptoms at onset and had a favorable prognosis. However, 90.5% of these patients had a vascular stenosis, which was higher than for patients with a cerebellar non-watershed infarction (74.3%). The four types of vascular lesions, intracranial, extracranial, combined, and no detectable stenosis, were 14.3%, 52.4%, 23.8%, and 9.5% in patients with a cerebellar watershed infarction and 33.8%, 16.2%, 24.3%, and 25.7% in patients with a non-watershed cerebellar infarction, respectively. Conclusion: Although patients with cerebellar watershed infarcts often had comparatively benign clinical manifestations and prognoses, such patients also had a high stenosis prevalence in major blood vessels, especially the extracranial segment in the vertebral artery, which required early intervention and treatment.