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.

Contrast enhanced MR angiography in pulmonary sequestration

Objective To evaluate the feasibility of contrast enhanced three-dimensional(3D)magnetic resonance angiography(MRA)in identifying the systemic blood supply in pulmonary sequestration.Methods Three patients who were suspected of pulmonary sequestration were examined by contrast enhanced 3D MRA.MR images were compared with surgical findings.Results Contrast enhanced 3D MRA clearly demonstrated systemic arteries from the descending thoracic aorta supplying the basilar segments of the lower lobe in each case.Pulmonary veins from these segments,which drained into the left atrium in two cases,were also detected.MRA images were consistent with those observed in surgery.Conclusion Contrast enhanced 3D MRA allows accurate diagnosis of pulmonary sequestration and may obviate the need for more invasive investigations.

Overview of multimodal MRI of intracranial Dural arteriovenous fistulas

Dural arteriovenous fistulas(DAVFs)include a wide range of pathological conditions that are associated with intracranial vessel abnormalities.While some types of DAVFs present with typical neuroimaging characteristics,others share overlapping pathological and neuroimaging features that can hinder accurate differentiation.Hence,misclassification of the various types of DAVFs is common.Thorough knowledge of DAVF imaging findings is essential to avoid such misinterpretations.Traditional digital subtraction angiography(DSA)is considered the gold standard for diagnosing and evaluating DAVFs.However,angiography cannot detect changes in a patient’s brain structure.Conventional magnetic resonance imaging(MRI)sequences,including MR angiography(MRA),allow the evaluation of DAVFs without ionizing radiation or invasiveness.Advanced MRI techniques,such as susceptibility-weighted imaging(SWI)and dynamic contrast-enhanced MRA,provide added value to real-time physio-pathological data regarding the hemodynamics of DAVFs.Beyond these techniques,new insights using high-resolution vascular wall MRI are incorporated for the noninvasive evaluation of DAVFs.This article reviews the pathophysiology of DAVFs,focusing on the specifics of MRI findings that facilitate their classification.The role of conventional and advanced MRI sequences for DAVFs was assessed using insights derived from the data provided by structured reports of multimodal MRIs to evaluate DAVFs.

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 non-contrast balanced steady-state free precession megnetic resonance angiography compared to contrast-enhanced megnetic resonance angiography in diagnosing renal artery stenosis： a meta-analysis

Background Balanced steady-state free precession MR angiography （b-SSFP MRA） has shown great promise in diagnosing renal artery stenosis （RAS） as a non-contrast MR angiography （NC-MRA） method. However, results from related studies are inconsistent. The purpose of this meta-analysis was to assess the accuracy of b-SSFP MIRA compared to contrast-enhanced MR angiography （CE-MRA） in diagnosing RAS. Methods English and Chinese studies that were published prior to September 4, 2013 and that assessed b-SSFP MRA diagnostic performance in RAS patients were reviewed. Quality of the literature was assessed independently by two observers. The statistical analysis was adopted by the software of Meta-Disc version 1.4. Using the heterogeneity test, a statistical effect model was chosen to calculate different pooled weighted values. The receiver operator characteristic （ROC） space and Spearman correlation coefficient were to explore threshold effect. Sensitivity analysis and the publication bias were performed to demonstrate if the pooled estimates were stable and reliable. We produced forest plots to calculate the pooled values and corresponding 95% confidence interval （Cl） of sensitivity, specificity, positive likelihood ratio （PLR）, negative likelihood ratio （NLR）, diagnostic odds ratio （DOR）, and constructed a summary receiver operating characteristic curve （SROC） to calculate the area under the curve （AUC）. Results A total of 10 high quality articles were used in this meta-analysis. The studies showed a high degree of heterogeneity. The ＂shoulder-arm＂ shape in the ROC plot and the Spearman correlation coefficient between the log（SEN） and Iog（1-SPE） suggested that there was a threshold effect. Sensitivity analysis demonstrated that the actual combined effect size was equal to the theoretical combined effect size. The publication bias was low after quality evaluation of the literature and the construction of a funnel plot. The pooled sensitivity was 0.88 （95% CI, 0.83-0.91） and pooled specificity was 0.94 （95% CI, 0.93-0.95）; pooled PLR was 14.57 （95% CI, 9.78-21.71]） and pooled NLR was 0.15 （95% CI, 0.11- 0.20）. The AUC was 0.964 3. Conclusion In contrast to CE-MRA, the b-SSFP MIRA is more accurate in diagnosing RAS, and may be able to replace other diagnostic methods in patients with renal insufficiency.