Magnetic Resonance Angiography Sequence Research Articles

Predicting long-term outcomes in patients with classical trigeminal neuralgia following microvascular decompression with an MRI-based radiomics nomogram: a multicentre study.

This study aimed to develop a clinical-radiomics nomogram to predict the long-term outcomes of patients with classical trigeminal neuralgia (CTN) following microvascular decompression (MVD). This retrospective study included 455 patients with CTN who underwent MVD from three independent institutions A total of 2030 radiomics features from the cistern segment of the trigeminal nerve were extracted computationally from the three-dimensional steady-state free precession and three-dimensional time-of-flight magnetic resonance angiography sequences. Using the least absolute shrinkage and selection operator regression, 16 features were chosen to develop radiomics signatures. A clinical-radiomics nomogram was subsequently developed in the development cohort of 279 patients via multivariate Cox regression. The predictive performance and clinical application of the nomogram were assessed in an external cohort consisting of 176 patients. Sixteen highly outcome-related radiomics features extracted from multisequence images were used to construct the radiomics model, with concordance indices (C-index) of 0.804 and 0.796 in the development and test cohorts, respectively. Additionally, a clinical-radiomics nomogram was developed by incorporating both radiomics features and clinical characteristics (i.e., pain type and degree of neurovascular compression) and yielded higher C-indices of 0.865 and 0.834 in the development and test cohorts, respectively. K‒M survival analysis indicated that the nomogram successfully stratified patients with CTN into high-risk and low-risk groups for poor outcomes (hazard ratio: 37.18, p < 0.001). Our study findings indicated that the clinical-radiomics nomogram exhibited promising performance in accurately predicting long-term pain outcomes following MVD. This model had the potential to aid clinicians in making well-informed decisions regarding the treatment of patients with CTN. Trigeminal neuralgia recurs in about one-third of patients after undergoing MVD. The clinical-radiomics nomogram stratified patients into high- and low-risk groups for poor surgical outcomes. Using this nomogram could better inform patients of recurrence risk and allow for discussion of alternative treatments.

Application of 3D-PCASL combined with t-ASL and MRA in the diagnosis of patients with isolated vertigo induced by posterior circulation ischemia

ObjectivesIsolated vertigo induced by posterior circulation ischemia (PCIV) can further progress into posterior circulation infarction. This study aimed to explore the diagnostic values of three-dimensional pseudo-continuous arterial spin labeling (3D-PCASL) combined with territorial arterial spin labeling (t-ASL) and magnetic resonance angiography (MRA) in visualizing and evaluating PCIV, seeking improved diagnostic tools for clinical guidance. Methods28 PCIVs (11 males, 17 females, aged from 55 to 83 years, mean age: 69.68 ± 9.01 years) and 28 healthy controls (HCs, 12 male, 16 female, aged from 56 to 87 years, mean age: 66.75 ± 9.86 years) underwent conventional magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), MRA, 3D-PCASL, and t-ASL. We compared the incidence of anatomic variants of the posterior circle of Willis in MRA, cerebral blood flow (CBF) and anterior collateral blood flow on postprocessing maps obtained from 3D-PCASL and t-ASL sequence between PCIVs and HCs. Chi-square test and paired t-test were analyzed statistically with SPSS 24.0 software. Results7 PCIVs (7/28, 25%) and 6 HCs (6/28, 21%) showed fetal posterior cerebral artery (FPCA) on MRA, including 1 HC, and 6 PCIVs with FPCA appeared hypoperfusion. 18 PCIVs (64%) and 2 HCs (7%) showed hypoperfusion in the posterior circulation (PC), including 1 HC and 7 PCIVs displayed anterior circulation collateral flow. Chi-square analyses demonstrated a difference in PC hypoperfusion between PCIVs and HCs, whether in the whole or FPCA-positive group assessment (P < 0.05). Paired t-test showed that the CBF values were significant difference for the bilateral PC asymmetrical perfusion in the PCIVs (P < 0.01). When compared to the bilateral PC symmetrical non-hypoperfusion area in the PCIVs and HCs, the CBF values were not significant (P > 0.05). The CBF values of the PC in PCIVs were lower than in HCs (P < 0.05). The reduction rate in the hypoperfusion side of the bilateral PC asymmetrical perfusion of the PCIVs ranged from 4% to 37%, while the HCs reduction rate was 7.7%. The average PC symmetrical perfusion average reduction rate of the PCIVs was 52.25%, while the HCs reduction rate was 42.75%. Conclusion3D-PCASL is a non-invasive and susceptible method for detecting hypoperfusion in PC, serving as a potential biomarker of PCIV. The suspected hypoperfusion in PC may be attributed to the emergence of FPCA and the manifestation of anterior collateral flow when combining t-ASL and MRA sequences. These findings demonstrated that 3D-PCASL combined with t-ASL and MRA sequences are the potential method to identify PCIV, leading to early diagnosis of PCIV and reducing the risk of progressing into infarction.

Evaluating the diagnostic performance of non-contrast magnetic resonance angiography sequences in the pre-procedural comprehensive analysis of direct carotid cavernous fistula.

Endovascular treatment of direct carotid cavernous fistula (DCCF) requires invasive diagnostic cerebral angiography for diagnosis and planning; however, a less invasive modality like magnetic resonance angiography (MRA) can be useful, especially in high-risk cases. This single-centre study evaluated a newer MR angiography (MRA) sequence, silent MRA and the traditional time of flight (TOF) MRA for pre-procedural treatment planning of DCCF. All consecutive DCCF patients who underwent TOF, silent MRA and diagnostic cerebral angiography were included in the study. Angiographic features like rent size, location, draining veins and collateral communicating arteries were analysed and compared between the two MRA sequences, with digital subtraction angiography (DSA) as the gold standard. Fifteen patients were included in the study. TOF MRA exhibited better sensitivity (76.9% vs 69.2%) in identifying the rent location, correctly pinpointing the location in 93.3% compared to 73.3% with silent MRA. Both MRA sequences showed good agreement with DSA for primary sac and rent size. TOF MRA correctly identified 86.2% of 210 total venous structures compared to 96% by silent MRA. Silent MRA demonstrated higher sensitivity (90% vs 76%) and accuracy (87.69 vs 94.36) in visualisation of involved veins compared to TOF MRA. Arterial characteristics of DCCF like rent location and rent size were better assessed by TOF MRA. Although both MRA identified venous features, silent MRA correlated better with DSA irrespective of the size and proximity to the site of the fistula. Combining both sequences can evaluate various angioarchitectural features of DCCF useful for therapeutic planning.

Diagnostic Performance of Pointwise Encoding Time Reduction with Radial Acquisition Subtraction-based MR Angiography in the Follow-up of Intracranial Aneurysms after Clipping.

While follow-up assessment of clipped aneurysms (CAs) using magnetic resonance angiography (MRA) can be challenging due to susceptibility artifacts, anovel MRA sequence pointwise encoding time reduction with radial acquisition (PETRA) subtraction-based MRA, has been developed to reduce these artifacts. The aim of the study was to validate the diagnostic performance of PETRA-MRA by comparing it with digital subtraction angiography (DSA) as areference for follow-up of CAs using a 3T MR scanner. Patients with clipping who underwent both PETRA-MRA and DSA between September 2019 and December 2021 were retrospectively included. Two neuroradiologists independently reviewed with the reconstructed images of PETRA-MRA to assess the visibility of the arteries around the clips and aneurysm recurrence or remnants of CA using a3-point scale. The diagnostic accuracy of PETRA-MRA was evaluated in comparison to DSA. The study included 34patients (28females, mean age 59 ± 9.6years) with 48CAs. The PETRA-MRA allowed visualization of the parent vessels around the clips in 98% of cases, compared to 39% with time-of-flight (TOF) MRA (p < 0.0001). The DSA confirmed 14 (29.2%) residual or recurrent aneurysms. The PETRA-MRA demonstrated a high accuracy, specificity, positive predictive value, and negative predictive value of 99.2%, 100%, 100%, and 97.8%, respectively, while the sensitivity was 66.7%. This retrospective study demonstrates that PETRA-MRA provides excellent visibility of adjacent vessels near clips and has ahigh diagnostic accuracy in detecting aneurysm remnants or recurrences in CAs. Further prospective studies are warranted to establish its utility as areliable alternative for follow-up after clipping.

Comparative study of non-contrast silent and time-of-flight magnetic resonance angiographic sequences in the evaluation of intracranial dural arteriovenous fistula

To compare the performance of two non-contrast magnetic resonance angiography (MRA) sequences, silent MRA and time of flight (TOF) MRA, in the evaluation of intracranial dural arteriovenous fistula (DAVF). Forty consecutive patients with DAVF were enrolled and evaluated prospectively using silent MRA, TOF MRA, and digital subtraction angiography (DSA). The location, Cognard classification, arterial feeders, and venous drainage were evaluated. The therapeutic strategy and possible route were predicted on both silent and TOF MRA and these were compared with DSA during subsequent endovascular treatment. Sensitivity and accuracy of silent and TOF MRA for localisation (96.4% versus 96% and 96% versus 95%, respectively) and classification (96% versus 94% and 96% versus 93.5%, respectively) were high. Silent MRA showed higher sensitivity than TOF MRA for arterial feeders and draining veins (87% versus 79% and 81.6% versus 67%). This improved to a sensitivity of 96.4% and 89% when prominent feeders were considered. The sensitivity and accuracy were 92.6% and 85.8% for immediate draining veins. Both silent and TOF MRA were accurate for therapeutic planning (96% versus 85%), although silent MRA was more accurate. Silent MRA can more reliably evaluate the various angioarchtectural components of DAVF compared to TOF MRA.

MRI Assessment of Brain Frailty and Clinical Outcome in Patients With Acute Posterior Perforating Artery Infarction.

Global brain health has gained increasing attention recently. Imaging markers of brain frailty have been related to functional outcomes in previous studies on anterior circulation; however, little data are available on imaging markers and posterior circulation. To investigate the impact of brain frailty on functional outcomes in patients with acute perforating artery infarction (PAI) of the posterior circulation. Prospective. One hundred patients (60.78 ± 9.51 years, 72% men) with acute posterior circulation PAI (determined by diffusion-weighted magnetic resonance imaging (MRI)/time-of-flight MR angiography). T1- and T2-weighted fast spin echo, T2-weighted fluid-attenuated inversion recovery, diffusion-weighted echo planar, gradient echo (susceptibility-weight imaging), and 3D time-of-flight MR angiography sequences at 3.0 T. Periventricular and deep white matter hyperintensities (WMH), enlarged perivascular spaces (EPVS) in the basal ganglia and centrum semiovale area, lacunes, cerebral microbleeds (CMB), and total brain frailty score by calculating the above imaging characters were rated visually by three radiologists with 9, 10, and 11 years of experience and one neuroradiologist with 12. Infarction volume was assessed using baseline diffusion-weighted imaging (DWI) data obtained within 24 hours of symptom onset. A modified Rankin Scale (mRS) score >1 on day 90 defined an adverse functional outcome. Associations between the imaging markers of brain frailty and functional outcomes were assessed. Fisher's exact test, Mann-Whitney U test, and multivariable binary logistic regression. A P value <0.05 was considered statistically significant. Adverse prognoses (mRS > 1) were observed in 34 (34%) patients. Infarction volume, periventricular WMH, deep WMH, basal ganglia EPVS, CMB, and the brain frailty score were significantly associated with adverse functional outcomes. An increased brain frailty score was significantly associated with unfavorable mRS score on day 90 (odds ratio 1.773, 95% confidence interval 1.237-2.541). Advanced MRI imaging markers of brain frailty, individually or combined as a total brain frailty score, were associated with worse functional outcomes after acute posterior circulation PAI. 3 TECHNICAL EFFICACY: Stage 3.

PO-03-139 HIGH-RESOLUTION CARDIAC MAGNETIC RESONANCE IMAGING FOR LEFT ATRIAL APPENDAGE SIZING AND THROMBUS EXCLUSION PRIOR TO DEVICE CLOSURE

Transesophageal echocardiography and cardiac computed tomography angiography are currently utilized for left atrial appendage closure (LAAC) planning. The advent of high-resolution cardiac magnetic resonance imaging (HR-CMR) now potentially allows for adequate spatial resolution for LAAC planning. This study sought to assess preoperative HR-CMR with software-based sizing vs intraoperative TEE for LAA sizing and thrombus exclusion prior to LAAC. This retrospective study conducted at The Ohio State University Wexner Medical Center included all patients who underwent preoperative HR-CMR and intraoperative TEE for LAAC with Watchman FLX (Boston Scientific, Marlborough, MA) from May to September 2022. For HR-CMR, magnetic resonance angiography (MRA) and late gadolinium enhancement (LGE) sequences were obtained for LAA sizing and thrombus exclusion respectively. A proprietary sizing software (TruPlan, Boston Scientific) was utilized to analyze the MRA sequence to characterize LAA anatomy, predict closure device size, and estimate device compression ratio. HR-CMR was compared to TEE for assessing accuracy of LAA thrombus exclusion, maximum ostial diameter, depth, lobe count, morphology, and accuracy of predicted device size. 16 patients were included, with baseline characteristics notable for 8 (50%) females, age 73 ± 6 years, 30 ± 7 kg/m2 body mass index, 54 ± 8% left ventricular ejection fraction, and 4 ± 2 CHA2DS2-VASc. 15 (94%) cases were successfully completed. There was no significant difference in LAA thrombus exclusion (CMR 14 (88%) vs TEE 16 (100%) cases, p=0.48), maximum ostial diameter (CMR 20.9 ± 4.2 vs TEE 20.6 ± 4.2 mm, p=0.99), depth (CMR 31.1 ± 7.8 vs TEE 26.8 ± 5.6 mm, p=0.09), lobe count (CMR 1.8 ± 0.8 vs TEE 1.4 ± 0.6 lobes, p=0.25), and morphology features (p=0.44). LAA assessments are summarized in Table I. The mean devices deployed per case was 1.1 ± 0.3. In 2 (13%) cases a device downsize was required. 1 case was aborted due to inability to access a very small LAA ostium. On 45-day TEE or CCTA, no peri-device leak ≥5 mm or device-related thrombus were noted. A comparison of standard vs high-resolution contrast-enhanced (CE)-MRA of the LAA is demonstrated in Figure 1. HR-CMR is a viable modality for preoperative LAA sizing and thrombus exclusion with promising results. HR-CMR may provide utility in cases where TEE or CCTA are contraindicated or unavailable.Tabled 1Table IMeasureHR-CMR (N=16)TEE (N=16)P-valueLAA thrombus accurately excluded14 (88%)16 (100%)0.484Minimum LAA ostial diameter (mm)18.0 ± 4.216.6 ± 3.40.335Target LAA ostial diameter (mm)*20.9 ± 4.220.6 ± 4.20.987LAA depth (mm)31.1 ± 7.826.8 ± 5.60.093Number of lobes1.8 ± 0.81.4 ± 0.60.250Morphology0.437Cactus4 (25%)3 (19%)Cauliflower0 (0%)2 (13%)Chicken wing5 (31%)2 (13%)Windsock7 (44%)8 (50%)Other0 (0%)1 (6%)LAA closure device size accurately predicted12 (75%)12 (75%)1.000Values presented as mean ± 1 standard deviation for continuous variables and n (%) for categorical variables. Abbreviations: HR-CMR = high resolution cardiac magnetic resonance imaging, LAA = left atrial appendage, TEE = transesophageal echocardiography. *Based on maximum diameter measured on TEE vs area-derived diameter on HR-CMR. Open table in a new tab

Neurosurgical management of proton beam therapy-induced moyamoya syndrome.

Proton beam therapy (PBT) is an increasingly used treatment modality for pediatric patients with brain tumors. Moyamoya syndrome (MMS) is well recognized as a complication of traditional photon radiotherapy, however its association with PBT is less well described. The authors discuss their initial experience with the neurosurgical management of MMS secondary to PBT in a large-volume pediatric neurovascular service. The authors performed a retrospective case review of consecutive children referred for neurosurgical management of MMS after PBT between 2009 and 2022. Patient demographic characteristics, oncological history and treatment, interval between PBT and MMS diagnosis, and MMS management were recorded. Clinical outcome at last review was classified as good if the modified Rankin Scale (mRS) score was ≤ 2 and/or the patient attended mainstream education without additional assistance. Poor outcome was defined as mRS score ≥ 3 and/or the patient received additional educational support. The recorded radiological outcomes included angiographic analysis of stenosis, evidence of brain ischemia/infarction on MRI, and postsurgical angiographic revascularization. Ten patients were identified. Oncological diagnosis included craniopharyngioma (n = 6), optic pathway glioma (1), ependymoma (1), Ewing sarcoma (1), and rhabdosarcoma (1). The median (interquartile range [IQR]) age at PBT was 5.1 (2.7-7.9) years. The median (IQR) age at MMS diagnosis was 7.8 (5.7-9.3) years. The median time between PBT and diagnosis of MMS was 20 (15-41) months. Six patients had poor functional status after initial oncological treatment and prior to diagnosis of MMS. All 10 patients had endocrine dysfunction, 8 had visual impairment, and 4 had behavioral issues prior to MMS diagnosis. Four patients had a perioperative ischemic event: 2 after tumor surgery, 1 after MMS surgical revascularization, and 1 after receiving a general anesthetic for an MRI scan during oncological surveillance. Seven children were treated with surgical revascularization, whereas 3 were managed medically. The incidence of ischemic events per cerebral hemisphere was reduced after surgical revascularization: only 1 patient of 7 had an ischemic event during the follow-up period after surgery. No children moved from good to poor functional status after MMS diagnosis. MMS can occur after PBT. Magnetic resonance angiography sequences should be included in surveillance MRI scans to screen for MMS, and families should be counseled about this complication. Management at a high-volume pediatric neurovascular center, including selective use of revascularization surgery, appears to maintain functional status in these children.

A Novel Approach to Vessel-Sparing Prostate Radiotherapy Using MR-Only Simulation and Non-Contrast MR Angiography: Vessel Delineation Feasibility and SBRT Dosimetric Analysis

<h3>Purpose/Objective(s)</h3> Erectile dysfunction is a common side effect of prostate cancer treatment, including prostate radiotherapy (RT). Vessel-sparing RT with avoidance of the internal pudendal artery (IPA) has shown promising rates of erectile function in non-randomized data. Implementation of vessel-sparing RT can be complicated by factors such as difficulty of MRI registration to planning CT and clinical desires to reduce routine use of IV contrast. We optimized a non-contrast MR angiography (ncMRA) sequence and compared IPA delineation on ncMRA with contrast MRA in a cohort of patients undergoing prostate stereotactic body RT (SBRT). We further performed dosimetric analysis on the IPAs. <h3>Materials/Methods</h3> Prostate cancer patients were prospectively enrolled on an IRB-approved MR imaging protocol. Treatment was with SBRT to a dose of 37.5 – 40 Gy in 5 fractions every other day. MR-only simulation was performed including MRA (2D T1w fast field echo (FFE) time-of-flight) and ncMRA (3D T1 FFE, 12 dynamics, temporal resolution = 14 seconds) sequences. Bilateral IPAs were delineated by a single blinded observer on MRA and ncMRA sequences. Analytical comparison between IPA contours on each patient was performed using mean distance to agreement (MDA), Dice similarity coefficient (DSC), and Jaccard index (JI). DSC and JI were also performed on IPA contour expansions of 2mm and 5mm. Dosimetry evaluated D50 and D05 on raw contours and 5mm expansion, and t-test compared dose on MRA and ncMRA. <h3>Results</h3> 10 patients were enrolled; 8 received 40 Gy, and 2 received 37.5 Gy. The median (range) analytical difference between IPA contours on MRA and ncMRA for MDA, DSC, and JI were 2.21 mm (0.99 – 4.16 mm), 0.54 (0.51 – 0.65), 0.37 (0.34 – 0.48), respectively. Using 2 mm contour expansion, DSC and JI were 0.69 (0.61 – 0.77) and 0.53 (0.44 – 0.63), while 5 mm expansion produced DSC and JI of 0.77 (0.69 – 0.85) and 0.62 (0.52 – 0.73). Dosimetrically, there was no difference in left and right IPA D50 or D05 between contours on MRA and ncMRA (Table). On 5mm expansion, the median (range) of D50 and D05 to IPA contours on ncMRA were 16.2 Gy (11.2 – 22.0 Gy) and 26.7 Gy (17.5 – 31.7 Gy). <h3>Conclusion</h3> This study found that delineation of IPAs using ncMRA was feasible and produced contours similar to those delineated on contrast MRA with no dosimetric differences. We feel that this agreement between imaging modalities demonstrates that ncMRA can be used alone for IPA delineation in vessel-sparing RT. Furthermore, the dosimetric findings of this study can serve as a baseline for expected IPA dose in prostate SBRT.

Magnetic Resonance Angiography and Cisternography fused images in acute ischemic stroke may save time during endovascular procedure revealing vessel anatomy

Background and purposeEndovascular treatment (EVT) is a time-dependent procedure that aims to remove the arterial blood flow obstruction in brain vessels in acute ischemic stroke. In our center, the MRI patient selection protocol in acute ischemic stroke is performed with DWI, FLAIR, MR angiography (MRA) and MR cisternography (MRC) sequences. MRA and MRC are promptly and automatically fused in order to have a clear detection of vessel anatomy, before and during EVT.Our study aim is to evaluate if the fusion process between MRA and MRC could be considered time-safe and could influence EVT duration or outcome. Materials and methods45 patients were retrospectively selected for the study and divided into 2 groups according to the presence of MRC sequence fused with MRA (Group 1) or not (Group 2 - controls). ResultsMRA and MRC fusion was able to depict vessel anatomy in all subjects of Group 1 (22 patients, 12 females; age 75.59 years ± 10.87). Group 1 presented EVT time reduction (p < 0.05;p = 0.040) (51.59 min ± 30.94) when compared to Group 2 (23 patients, 13 females; age 75.04 years ± 12.12) (71.96 min ± 34.55) of 20.37 min average. No differences between groups were detected evaluating: NIHSS at admission (p = 0.49) and discharge (p = 0.67), pre-stroke mRS (p = 0.89), mRS at 90 days (p = 0.62), ASPECT (p = 0.98) and ASPECT-DWI scores (p = 0.93), time from symptom onset to groin puncture (p = 0.80), thromboaspiration vs combined technique (p = 0.67), EVT success (p = 0.63). ConclusionFusion of MRA and MRC is a safe and promising technique in promptly revealing vascular anatomy beyond vessel obstruction, and can play a role in EVT duration reduction.

Non-invasive angiographic analysis of dural carotid cavernous fistula using time-of-flight MR angiography and silent MR angiography: a comparative study.

A non-invasive, reliable imaging modality that characterizes cavernous sinus dural arteriovenous fistula (CSDAVF) is beneficial for diagnosis and to assess resolution on follow-up. To assess the utility of 3D time-of-flight (TOF) and silent magnetic resonance angiography (MRA) for evaluation of CSDAVF from an endovascular perspective. This prospective study included 37 patients with CSDAVF, who were subjected to digital subtraction angiography (DSA) and 3-T MR imaging with 3D TOF and silent MRA. The main arterial feeders, fistula site, and venous drainage pattern were evaluated, and the results were compared with DSA findings. The diagnostic confidence scores were also recorded using a 4-point Likert scale. Silent MRA correlated better for shunt site localization and angiographic classification (86% vs. 75% and 83% vs. 75%, respectively) compared to TOF MRA. The proportion of arterial feeders detected was marginally significant for silent MRA over TOF MRA sequences (92.8% vs. 89.5%; P=0.048), though for veins both were comparable. Sensitivity of silent MRA was higher for identification of cortical venous reflux (CVR) (90.9% vs. 81.8%) and deep venous drainage (82.4% vs. 64.7%), while specificity was >90% for both modalities. The overall diagnostic confidence score fared better for silent MRA for venous assessment (P < 0.001) as well as fistula point identification (P < 0.001), while no significant difference was evident with TOF MRA for arterial feeders (P=0.06). Various angiographic components of CSDAVF could be identified and delineated by 3D TOF and silent MRA, though silent MRA was superior for overall diagnostic assessment.

The preoperative evaluation value of 3D-slicer program before microsurgical vascular decompression in patients with hemifacial spasm

BackgroundTo compare the diagnostic accuracy of 3D fast imaging employing steady-state acquisition (FIESTA) combined with 3D-time-of-flight (TOF) MR angiography (MRA) sequences (FTMS) and 3D-reconstuction synthesized by 3D-slicer program in evaluation the neurovascular relationships and offending vessels preoperatively in patients with hemifacial spasm (HFS). MethodsClinical data of HFS patients who underwent microsurgical vascular decompression (MVD) were analyzed. All patients underwent MRA scans with FTMS and 3D-reconstruction before surgery. The neurovascular relationship and offending vessels were evaluated and compared with intraoperative findings. ResultsForty patients were included in this study, 18 (45%) of them were male. The mean age was 49.6 years. The Kappa identity tests identified the agreement between the FTMS and intraoperative findings in evaluating the neurovascular relationship and offending vessel was 0.263 and 0.643, respectively. The agreement between the 3D-reconstruction and intraoperative findings was 0.633 and 0.921 respectively. There was borderline significant difference between the two methods in predicting neurovascular relationship (χ2 = 9.363, P = 0.053), and there were significant differences between the two methods in predicting offending vessels (χ2 = 188.408, P < 0.001). The sensitivity and specificity of FTMS in evaluating the neurovascular relationship were 89.7% and 100%, respectively, while those with 3D-reconstruction were both 100%. Moreover, the correct 3D- reconstruction examinations in predicting vessel and nerve relationships (r = 0.634, P = 0.034) and offending vessels (r = 0.652, P = 0.028) were significantly correlated with completely symptoms remission. ConclusionsThe 3D-reconstuction synthesized by 3D-slicer program was more accurate than FTMS in preoperative evaluation of neurovascular relationship and offending vessel. The technique is expected to be helpful in preoperative evaluation. Availability of data and materialThe dataset used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Usefulness of silent magnetic resonance angiography (MRA) for the diagnosis of atherosclerosis of the internal carotid artery siphon in comparison with time-of-flight MRA

Background and purposeFlow visualization in 3D time-of-flight MRA (3D-TOF MRA) may be limited for internal carotid artery siphon owing to turbulent artifact. The purpose of this study was to compare the usefulness of Silent MRA and 3D-TOF MRA to assess atherosclerosis of the internal carotid artery siphon.Material and methodsA total of 106 patients with suspected cerebrovascular disease were included. All patients were scanned with Silent MRA and 3D-TOF MRA sequences and also underwent DSA examination. Two observers independently assessed the TOF MRA and Silent MRA images of atherosclerosis of the internal carotid artery siphon. The diagnostic efficacy of two MRA methods in evaluating atherosclerosis of the carotid siphon was performed by using receiver operating characteristic (ROC) curve analysis. Interobserver reliability was also assessed using weighted kappa statistics.ResultsImage of Silent MRA sequence had higher subjective evaluation scores and significantly high CNR between the carotid siphon and the background tissues than the image of 3D-TOF MRA sequence (P < 0.05). The AUC was 0.928 (95% CI 0.909–0.986) for Silent MRA, which was significantly higher than that of 3D-TOF MRA (0.671, 95% CI 0.610–0.801, P < 0.05). Silent MRA had high sensitivity, specificity and accuracy than 3D-TOF MRA for visualization of the carotid siphon.ConclusionsSilent MRA as a new angiographic modality is superior to 3D-TOF MRA for visualization of the carotid siphon, and maybe an alternative to 3D-TOF MRA in the diagnosis of atherosclerosis of the carotid siphon.

Accelerated Two-Point Dixon MR Angiography Improves Diagnostic Performance for Cervical Artery Diseases.

Nonenhanced MR angiography (MRA) studies are often used to manage acute and chronic large cervical artery disease, but lengthy scan times limit their clinical usefulness. To develop an accelerated cervical MRA and test its diagnostic performance. Prospective. Patients with cervical artery disease (n= 32, 17 males). 3.0 T; accelerated two-point Dixon three-dimensional Cartesian spoiled gradient-echo (FLEXA) and conventional time-of-flight MRA (cMRA) sequences. All patients underwent FLEXA (1'28″) and cMRA (6'47″) acquisitions. Quantitative evaluation (artery-to-background signal ratio and a blur metric) and qualitative evaluation using diagnostic performance measured by the sensitivity, specificity, and positive/negative predictive values (PPV/NPV), and vessel and plaque visualization scores from three board-certified radiologists' (with 10, 11, and 12 years of experience) independent readings using maximum intensity projection (MIP) for luminal diseases and axial images for plaque. The reference standards were contrast-enhanced angiography and fat-saturated T1-weighted images, respectively. All measures were compared between FLEXA and cMRA using the paired t, Wilcoxon signed-rank, McNemar's, or chi-squared test, as appropriate. Interreader agreement was assessed using Cohen's κ. P< 0.05 was considered statistically significant. The artery-to-background signal ratio was significantly higher for FLEXA (FLEXA: 7.20 ± 1.63 [fat]; 4.26 ± 0.52 [muscle]; cMRA: 2.57 ± 0.49 [fat]), while image blurring was significantly less (FLEXA: 0.24 ± 0.016; cMRA: 0.30 ± 0.029). In luminal disease detection, sensitivity (FLEXA: 0.97/0.91/0.91; cMRA:0.71/0.69/0.63), specificity (FLEXA: 0.98/0.93/0.98; cMRA:0.93/0.85/0.92), PPV (FLEXA: 0.92/0.86/0.86; cMRA: 0.64/0.5/0.58), and NPV (FLEXA: 0.99/0.98/0.98; cMRA: 0.92/0.91/0.9) were significantly higher for FLEXA. interreader agreement was substantial to almost perfect for FLEXA (κ= 0.82/0.86/0.78) and moderate to substantial for cMRA (κ= 0.67/0.56/0.57). MIP visualization scores were significantly higher for FLEXA, with substantial to almost perfect interreader agreement (FLEXA: κ= 0.83/0.86/0.82; cMRA: κ= 0.89/0.79/0.79). In plaque detection, sensitivity (FLEXA: 0.9/0.9/0.7; cMRA: 0.3/0.6/0.2) and specificity (FLEXA: 1/0.87/1; cMRA: 0.93/0.63/0.97) were significantly higher for FLEXA in two of three readers. The interreader plaque detection agreement was fair to substantial (FLEXA: κ= 0.63/0.69/0.48; cMRA: κ= 0.21/0.45/0.20). Side-by-side plaque and vessel wall visualization was superior for FLEXA in all readers, with moderate to substantial interreader agreement (plaque: κ= 0.73/0.73/0.77; vessel wall: κ= 0.57/0.40/0.39). FLEXA enhanced visualization of the cervical arterial system and improved diagnostic performance for luminal abnormalities and plaques in patients with cervical artery diseases. 1 TECHNICAL EFFICACY STAGE: 2.

Inter-Observer Reliability of Fused Time-of-Flight MR Angiography and 3D Steady State Sequence versus 3D Contrast Enhanced Images in Evaluation of Neurovascular Compression

Purpose: Is to evaluate the accuracy of fused 3D time-of-flight (TOF) MR angiography and 3D Steady-State sequence (FIESTA) versus 3D contrast-enhanced T1 weighted images in evaluation of neurovascular compression via an inter-observer agreement protocol. Methods: Patients presented with trigeminal neuralgia, tinnitus, or facial hemispasm were examined using 3D-TOF-MRA, 3D-FIESTA, and 3D contrast-enhanced T1WI of the cerebellopontine angle to assess neurovascular compression. Two independent readers assessed the location, signal alteration, offending vascular structure, and grade of neurovascular compression using fused 3D-TOF-MRA and 3D-FIESTA versus contrast-enhanced T1 weighted images. The Kappa test for interobserver agreement was done. Results: The final study cohort consisted of 56 patients (42 females and 14 males) with a mean age of 38.25 ± 1.94. AICA was the offending vessel for 32 (57.1%) patients. The most common offending nerve was the trigeminal nerve in 26 patients, followed by facial/vestibulocochlear complex in 18 patients, and solely the 8th nerve in 12 patients. All three grades of compression were encountered in this study with percentages of 48.2% (27/56), 30.3% (17/56), and 21.4% (12/56) for grades I, II, III respectively. Fused TOF and steady-state images, and contrast-enhanced images showed perfect agreement for detection of the side of compression, the relation between nerve and vascular loop, offended neural segment, and offending vessel, while showing good agreement regarding the degree of compression. Conclusion: Fused TOF and steady-state images provide sufficient data to diagnose and grade microvascular compression syndromes comparable to contrast-enhanced images.

Spiral 3D time-of-flight MR angiography for rapid non-contrast carotid artery imaging: Clinical feasibility and protocol optimization.

To assess the clinical feasibility of spiral 3D Time-Of-Flight (TOF) MR Angiography (MRA) sequence variants for rapid non-contrast carotid artery imaging. Nine different 3D TOF MRA sequences were acquired in nine healthy volunteers on a standard clinical 1.5T scanner. Three cartesian sequences (fully sampled (10:15min), accelerated with SENSE (05:08min), accelerated with Compressed SENSE (03:32min)) and six different spiral sequences were acquired (spiral acquisition windows ranging from 10 to 5ms (01:32min-03:05min)). Three readers graded the images qualitatively in terms of overall image quality, vessel sharpness, inhomogeneous intraluminal signal, background noise, visualization of large and small vessels and overall impression of the number of visible vessels. Cross-sectional areas of the vessel lumen were measured and vessel sharpness was quantified. The SENSE and Compressed SENSE accelerated cartesian sequences and the Spiral 6ms and 5ms sequences were deemed comparable to the fully sampled cartesian sequence in most qualitative categories (p>0.05) based on exact binomial tests. The Spiral 6ms and 5ms sequences achieved a scan time reduction of 75.3% and 69.9% respectively compared to the fully sampled cartesian sequence. The spiral sequences (generally) exhibited improved subjective vessel sharpness (p<0.01-p=0.13) but increased background noise (p=0.03-p=0.25). Cross-sectional area measurements were similar between all sequences (Krippendorff's alpha: 0.955-0.982). Quantitative vessel sharpness was increased for all spiral sequences compared to all cartesian sequences (p=0.004). Spiral 3D TOF MRA sequences with a spiral acquisition window of 5ms or 6ms may be used for accurate, rapid, clinical non-contrast carotid artery imaging.

Abstract 10251: Intracranial Aneurysms in Sickle Cell Adults Screened by Mra

Introduction: Sickle cell disease(SCD) is the most common genetic disease globally. It is an autosomal recessive disease that affects the β-globin chain which most often presents with anemia and vaso-occlusive symptoms. This condition includes multiples genotypes/phenotypes, the most common of which is HbSS (homozygosity for Hemoglobin S); others are compound heterozygosity with HbC variant (HbSC) and HbS-β-thalassemia (HbSβ+/HbSβ0). Stroke occurs in up to 25% of SCD patients and MRI screening is already recommended by the American Society of Hematology. Small case series have shown a higher prevalence of intracranial aneurysms (ICAN) in SCD, and MR angiography (MRA) may therefore be of benefit for the detection of arterial pathology. Hypothesis: There is an increased prevalence of ICAN in adults with SCD; Frequency of anevrysms is associated with SCD genotype and age. Methods: Adult patients from the SCD clinic of our institution were screened with 3T brain MR complemented with MRA in order to accurately determine the prevalence of ICAN. Results: Our study included 245 asymptomatic SCD adults (369 MRIs). Median age was 32; 52% were women. The overall prevalence of ICAN was 0.11 (0.95 CI 0.07-0.15). All aneurysms were saccular ≤ 10 mm. Forty-four aneurysms were detected in 27 patients with a third presenting with multiple aneurysms. Genotype subgroup analysis revealed a higher prevalence of ICAN in SS/Sb0 (0.17; 0.95 CI 0.11-0.25) compared to the SC/Sb+ (0.06; 0.95 CI 0.02-0.11) (p = 0.007). An association between age and ICAN was also statistically significant (p = 0.03) with stratification revealing a higher prevalence of ICAN for &gt;30 years old, 0.15 (0.95 CI 0.09-0.21). In addition, in patients aged 18-30, the prevalence was 0.06 (0.95 CI 0.26-0.12). Conclusions: This is the largest cohort of SCD adults screened specifically with MRA. We confirm with higher confidence the increased prevalence of ICAN in this population which is in the range of other established indications for aneurysm screening such as Familial Intracranial Aneurysm and Autosomal Dominant Polycystic Kidney Disease. This knowledge could therefore impact the existing screening guidelines for SCD patients via systematic inclusion of an MRA sequence in the recommended imaging protocol.

Usefulness of contrast-enhanced 3D MR angiography and contrast-enhanced 3D T1 sequence for detecting intracranial infectious aneurysms in infectious endocarditis

ObjectivesTo assess the diagnostic value of contrast-enhanced MRA (CE MRA) and CE 3D-T1 for identifying intracranial infectious aneurysms (IIAs) in infective endocarditis (IE) with digital substraction angiography (DSA) as reference. MethodsTwenty-one IE patients (14 males; mean age: 53 years) with 30 IIAs, diameter ranging 1.5–15 mm (<3mm, n = 14, 46.7%; 3–5 mm, n = 12,40%), underwent CE MRA and CE 3D-T1 at 1.5 T. Two readers evaluated images for aneurysm detection, characterization, quality of visualization. DSA was obtained at a median of 3 days (range 1–15) after MRI. ResultsThe sensitivity, specificity, positive and negative predictive values and accuracy of IIA detection were respectively: 80%, 100%, 100%, 82.3%, 90% for CE MRA and 86.7%, 100%, 100%, 88.2%, 93.3% for CE 3D T1 compared to DSA.No significant difference was observed between CE MRA and CE 3D-T1 for accuracy and quality of visualization. All IIAs of ≥3 mm in diameter (16/30; 53.%) were identified by both sequences, which were also able to detect IIAs ≤ 3 mm (n = 14/30, 46.7%). False negatives were observed with both sequences for 4 IIAs of <2 mm, 3 being compressed by hemorrhagic lesions. Two other IIAs of <2 mm were overlooked by CE MRA. CE 3D-T1 overestimated IIAs luminal diameter by 8% relatively to DSA (P = NS).Intra and inter-observer agreement were good and similar with both methods. ConclusionBoth CE MRA and CE 3D-T1 have good accuracy compared to DSA detection and characterization of IIAs. CE 3D-T1 also evaluates anatomical relationships of IIAs, which could help DSA location and endovascular treatment.

Contrast-enhanced body magnetic resonance angiography: how we do it.

This review introduces the basic principles of contrast-enhanced magnetic resonance (MR) angiography and details four contrast-enhanced MR angiography sequences for body imaging with extracellular gadolinium-based contrast agents in pediatric patients. Specifically, this review covers (1) respiratory-navigated, cardiac-gated MR angiography; (2) time-resolved MR angiography; (3) conventional MR angiography; and (4) modified spoiled gradient echo variants. We present and discuss indications, technical considerations, sequence optimization, advantages and disadvantages, along with practical tips and illustrative case examples for each sequence.

Radial self-navigated native magnetic resonance angiography in comparison to navigator-gated contrast-enhanced MRA of the entire thoracic aorta in an aortic patient collective

BackgroundThe native balanced steady state with free precession (bSSFP) magnetic resonance angiography (MRA) technique has been shown to provide high diagnostic image quality for thoracic aortic disease. This study compares a 3D radial respiratory self-navigated native MRA (native-SN-MRA) based on a bSSFP sequence with conventional Cartesian, 3D, contrast-enhanced MRA (CE-MRA) with navigator-gated respiration control for image quality of the entire thoracic aorta.MethodsThirty-one aortic native-SN-MRA were compared retrospectively (63.9 ± 10.3 years) to 61 CE-MRA (63.1 ± 11.7 years) serving as a reference standard. Image quality was evaluated at the aortic root/ascending aorta, aortic arch and descending aorta. Scan time was recorded. In 10 patients with both MRA sequences, aortic pathologies were evaluated and normal and pathologic aortic diameters were measured. The influence of artifacts on image quality was analyzed.ResultsCompared to the overall image quality of CE-MRA, the overall image quality of native-SN-MRA was superior for all segments analyzed (aortic root/ascending, p < 0.001; arch, p < 0.001, and descending, p = 0.005). Regarding artifacts, the image quality of native-SN-MRA remained superior at the aortic root/ascending aorta and aortic arch before and after correction for confounders of surgical material (i.e., susceptibility-related artifacts) (p = 0.008 both) suggesting a benefit in terms of motion artifacts. Native-SN-MRA showed a trend towards superior intraindividual image quality, but without statistical significance. Intraindividually, the sensitivity and specificity for the detection of aortic disease were 100% for native-SN-MRA. Aortic diameters did not show a significant difference (p = 0.899). The scan time of the native-SN-MRA was significantly reduced, with a mean of 05:56 ± 01:32 min vs. 08:51 ± 02:57 min in the CE-MRA (p < 0.001).ConclusionsSuperior image quality of the entire thoracic aorta, also regarding artifacts, can be achieved with native-SN-MRA, especially in motion prone segments, in addition to a shorter acquisition time.