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The aim of the study was to evaluate the role of pseudocontinuous arterial spin labeling perfusion (pCASL-perfusion) in preoperative assessment of cerebral glioma grades. The study group consisted of 253 patients, aged 7-78 years with supratentorial gliomas (65 low-grade gliomas (LGG), 188 high-grade gliomas (HGG)). We used 3D pCASL-perfusion for each patient in order to calculate the tumor blood flow (TBF). We obtained maximal tumor blood flow (maxTBF) in small regions of interest (30 ± 10 mm 2 ) and then normalized absolute maximum tumor blood flow (nTBF) to that of the contralateral normal-appearing white matter of the centrum semiovale. MaxTBF and nTBF values significantly differed between HGG and LGG groups (p < 0.001), as well as between patient groups separated by the grades (grade II vs. grade III) (p < 0.001). Moreover, we performed ROC-analysis which demonstrated high sensitivity and specificity in differentiating between HGG and LGG. We found significant differences for maxTBF and nTBF between grade III and IV gliomas, however, ROC-analysis showed low sensitivity and specificity. We did not observe a significant difference in TBF for astrocytomas and oligodendrogliomas. Our study demonstrates that 3D pCASL-perfusion as an effective diagnostic tool for preoperative differentiation of glioma grades., (© 2022. The Author(s).)

Background/aim: The presented study aimed to evaluate the utility of magnetic resonance angiography (MRA) in the pediatric population with nutcracker syndrome., Materials and Methods: Patients with suggestive clinical symptoms and laboratory findings and got the diagnosis of nutcracker syndrome with Doppler ultrasonography between January 2011–2019 were included in the study. In addition, children who had renal MRA due to hypertension were evaluated as the control group. MRA images of all patients were examined retrospectively by three radiologists at different levels of experience, and the superior mesenteric artery angle, aorta-mesenteric distance, left renal vein diameter both in the regions of aorta-mesenteric, and renal hilum were recorded., Results: Forty-five patients diagnosed with nutcracker syndrome were included in the study. The mean age of patients was 12 (4–16) and 30 (67%) were female. As the control group, 25 patients with hypertension who had MRA were included and they had a mean age of 12 (1–18) and 19 (76%) were male. The mean superior mesenteric artery angle was 26.5 ° (16–73 ± 12) in the patient group and 57.8 ° (25–139, ± 33) in the control group (p < 0.001); the mean aorta-mesenteric distance was 3.3 mm (1.7–6.5, ± 1.1) in the patient group and 8 mm (3.4–32, ± 5.9) in the control group (p < 0.001). MRA measurements of three radiologists were consistent with each other., Conclusion: MRA imaging can be applied as an alternative diagnostic method for Doppler ultrasonography and multidetector CT examinations by radiologists with different experience levels in pediatric patients with nutcracker syndrome., Competing Interests: Declarations of interest: there is no conflict of interest., (This work is licensed under a Creative Commons Attribution 4.0 International License.)

Background: Hybrid PET/MR imaging has significant potential in cardiology due to its combination of molecular PET imaging and cardiac MR. Multi-tissue-class MR-based attenuation correction (MRAC) is necessary for accurate PET quantification. Moreover, for thoracic PET imaging, respiration is known to lead to misalignments of MRAC and PET data that result in PET artifacts. These factors can be addressed by using multi-echo MR for tissue segmentation and motion-robust or motion-gated acquisitions. However, the combination of these strategies is not routinely available and can be prone to errors. In this study, we examine the qualitative and quantitative impacts of multi-class MRAC compared to a more widely available simple two-class MRAC for cardiac PET/MR., Methods and Results: In a cohort of patients with cardiac sarcoidosis, we acquired MRAC data using multi-echo radial gradient-echo MR imaging. Water-fat separation was used to produce attenuation maps with up to 4 tissue classes including water-based soft tissue, fat, lung, and background air. Simultaneously acquired 18F-fluorodeoxyglucose PET data were subsequently reconstructed using each attenuation map separately. PET uptake values were measured in the myocardium and compared between different PET images. The inclusion of lung and subcutaneous fat in the MRAC maps significantly affected the quantification of 18F-fluorodeoxyglucose activity in the myocardium but only moderately altered the appearance of the PET image without introduction of image artifacts., Conclusion: Optimal MRAC for cardiac PET/MR applications should include segmentation of all tissues in combination with compensation for the respiratory-related motion of the heart. Simple two-class MRAC is adequate for qualitative clinical assessment., (© 2020. American Society of Nuclear Cardiology.)

Background: 18 F-Fluoride uptake denotes calcification activity in aortic stenosis and atherosclerosis. While PET/MR has several advantages over PET/CT, attenuation correction of PET/MR data is challenging, limiting cardiovascular application. We compared PET/MR and PET/CT assessments of 18 F-fluoride uptake in the aortic valve and coronary arteries., Methods and Results: 18 patients with aortic stenosis or recent myocardial infarction underwent 18 F-fluoride PET/CT followed immediately by PET/MR. Valve and coronary 18 F-fluoride uptake were evaluated independently. Both standard (Dixon) and novel radial GRE) MR attenuation correction (AC) maps were validated against PET/CT with results expressed as tissue-to-background ratios (TBRs). Visually, aortic valve 18 F-fluoride uptake was similar on PET/CT and PET/MR. TBR MAX values were comparable with radial GRE AC (PET/CT 1.55±0.33 vs. PET/MR 1.58 ± 0.34, P = 0.66; 95% limits of agreement - 27% to + 25%) but performed less well with Dixon AC (1.38 ± 0.44, P = 0.06; bias (-)14%; 95% limits of agreement - 25% to + 53%). In native coronaries, 18 F-fluoride uptake was similar on PET/MR to PET/CT regardless of AC approach. PET/MR identified 28/29 plaques identified on PET/CT; however, stents caused artifact on PET/MR making assessment of 18 F-fluoride uptake challenging., Conclusion: Cardiovascular PET/MR demonstrates good visual and quantitative agreement with PET/CT. However, PET/MR is hampered by stent-related artifacts currently limiting clinical application., (© 2019. The Author(s).)

Background: Intracranial atherosclerotic stenosis (ICAS) is one of the most common causes of stroke worldwide and confers a high risk of stroke recurrence, despite aggressive management of risk factors., Objectives: This study identified the role of risk factors and risk of vascular events in subjects with asymptomatic ICAS for improved risk stratification., Methods: Stroke-free participants in the NOMAS (Northern Manhattan Study) trial, prospectively followed since 1993, underwent a brain magnetic resonance angiogram from 2003 to 2008. The study rated stenosis in 11 brain arteries as: 0: no stenosis; 1: <50% or luminal irregularities; 2: 50%-69%; and 3: ≥70% stenosis or flow gap. The study ascertained vascular events during the post-magnetic resonance imaging (MRI) period. Proportional odds regression quantified the association of pre-MRI exposures, and proportional hazard adjusted models were built to identify the risk of events in the post-MRI period., Results: The included sample included 1,211 participants from NOMAS (mean age: 71 ± 9 years; 59% women; 65% Hispanic; 45% had any stenosis). Older age (OR: 1.02 per year; 95% CI: 1.01 to 1.04), hypertension duration (OR: 1.01 per year; 95% CI: 1.00 to 1.02), higher number of glucose-lowering drugs (OR: 1.64 per each medication; 95% CI: 1.24 to 2.15), and high-density lipoprotein (OR: 0.96 per mg/dL; 95% CI: 0.92 to 0.99) were associated with ICAS. The highest event risk was noted among participants with ICAS ≥70% (5.5% annual risk of vascular events; HR: 2.1; 95% CI:1.4 to 3.2; compared with those with no ICAS)., Conclusions: ICAS is an imaging marker of established atherosclerotic disease in stroke-free subjects, and incidental diagnosis of ICAS should trigger a thorough assessment of vascular health., Competing Interests: Funding Support and Author Disclosures This work was supported by the National Institutes of Health (grants R01 AG057709, R01 AG066162, R01 NS36286). The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 American College of Cardiology Foundation. All rights reserved.)

Cardiac magnetic resonance imaging (CMR) is an important tool for the non-invasive diagnosis of a variety of cardiovascular diseases. Parametric mapping with multi-contrast CMR is able to quantify tissue alterations in myocardial disease and promises to improve patient care. However, magnetic resonance imaging is an inherently slow imaging modality, resulting in long acquisition times for parametric mapping which acquires a series of cardiac images with different contrasts for signal fitting or dictionary matching. Furthermore, extra efforts to deal with respiratory and cardiac motion by triggering and gating further increase the scan time. Several techniques have been developed to speed up CMR acquisitions, which usually acquire less data than that required by the Nyquist-Shannon sampling theorem, followed by regularized reconstruction to mitigate undersampling artefacts. Recent advances in CMR parametric mapping speed up CMR by synergistically exploiting spatial-temporal and contrast redundancies. In this article, we will review the recent developments in multi-contrast CMR image reconstruction for parametric mapping with special focus on low-rank and model-based reconstructions. Deep learning-based multi-contrast reconstruction has recently been proposed in other magnetic resonance applications. These developments will be covered to introduce the general methodology. Current technical limitations and potential future directions are discussed. This article is part of the theme issue 'Synergistic tomographic image reconstruction: part 1'.

Conventional magnetic resonance imaging (MRI) is hampered by long scan times and only qualitative image contrasts that prohibit a direct comparison between different systems. To address these limitations, model-based reconstructions explicitly model the physical laws that govern the MRI signal generation. By formulating image reconstruction as an inverse problem, quantitative maps of the underlying physical parameters can then be extracted directly from efficiently acquired k-space signals without intermediate image reconstruction-addressing both shortcomings of conventional MRI at the same time. This review will discuss basic concepts of model-based reconstructions and report on our experience in developing several model-based methods over the last decade using selected examples that are provided complete with data and code. This article is part of the theme issue 'Synergistic tomographic image reconstruction: part 1'.

While the time window for reperfusion after ischemic stroke continues to increase, many patients are not candidates for reperfusion under current guidelines that allow for reperfusion within 24 h after last known well time; however, many case studies report favorable outcomes beyond 24 h after symptom onset for both spontaneous and medically induced recanalization. Furthermore, modern imaging allows for identification of penumbra at extended time points, and reperfusion risk factors and complications are becoming better understood. Taken together, continued urgency exists to better understand the pathophysiologic mechanisms and ideal setting of delayed recanalization beyond 24 h after onset of ischemia.

Background/aim: Takayasu’s arteritis (TA) is a rare, large-vessel vasculitis of unknown etiology, affecting aortic arch, and its main branches. Noninvasive imaging methods are frequently used in diagnosis and follow-up in Takayasu’s arteritis. Studies investigating optimal timing of follow up imaging are rare. This study is aimed to investigate the radiologic changes in vascular involvements of Takayasu’s arteritis patients one year after diagnosis., Materials and Methods: Database of our Vasculitis Center was analyzed retrospectively and 97 patients were included into the study. Demographic, clinical, radiological, and therapeutic findings of patients were recorded. Patients with follow-up imaging after approximately one year of diagnosis were recruited into further analysis. Radiological changes and the effect of different immunosuppressive agents on vascular involvements were investigated., Results: Mean age and disease duration of patients were 43.0 and 9.0 years. The most commonly used imaging methods/modalities for the diagnosis of TA were computer tomography-angiography (CT-Ang) (58.8%), magnetic resonance-angiography (MR-Ang) (29.9%), and doppler ultrasonography (11.3%). Subclavian and common carotid arteries were the most frequently involved vessels. Fifty-three patients underwent follow-up imaging after one year of diagnosis and, in 64% of patients, same imaging method had been used. MR- Ang (62.3%) and CT-Ang (35.9%) were the most preferred follow-up imaging studies. Sixty-eight percent of patients had stable vascular involvement, 28% had progression, and 4% had regression. No difference was found in radiological changes regarding patients with usage of different immunosuppressive agents (P = 0.634). There was no association between the change in serum acute phase reactants and radiological disease activity., Conclusion: The most commonly used imaging modality for the diagnosis of TA was CT-Ang, whereas MR-Ang was the most preferred for follow-up. Almost 30% of TA patients in our Vasculitis Center had progression at around one year concordant with previous literature. A follow-up imaging at around one year of treatment seems feasible in management of TA., Competing Interests: All authors declare none of conflict of interests., (This work is licensed under a Creative Commons Attribution 4.0 International License.)

Background: Pulmonary vein (PV) stenosis is a complication of atrial fibrillation (AF) ablation. The incidence of PV stenosis after routine post-ablation imaging remains unclear and is limited to single-centre studies. Our objective was to determine the incidence and predictors of PV stenosis following circumferential radiofrequency ablation in the multicentre Adenosine Following Pulmonary Vein Isolation to Target Dormant Conduction Elimination (ADVICE) trial., Methods: Patients with symptomatic AF underwent circumferential radiofrequency ablation in one of 13 trial centres. Computed tomographic (CTA) or magnetic resonance (MRA) angiography was performed before ablation and 90 days after ablation. Two blinded reviewers measured PV diameters and areas. PVs with stenosis were classified as severe (> 70%), moderate (50%-70%), or mild (< 50%). Predictors of PV stenosis were identified by means of multivariable logistic regression., Results: A total of 197 patients (median age 59.5 years, 29.4% women) were included in this substudy. PV stenosis was identified in 41 patients (20.8%) and 47 (8.2%) of 573 ablated PVs. PV stenosis was classified as mild in 42 PVs (7.3%) and moderate in 5 PVs (0.9%). No PVs had severe stenosis. Both cross-sectional area and diameter yielded similar classifications for severity of PV stenosis. Diabetes was associated with a statistically significant increased risk of PV stenosis (OR 4.91, 95% CI 1.45-16.66)., Conclusions: In the first systematic multicentre evaluation of post-ablation PV stenosis, no patient acquired severe PV stenosis. Although the results are encouraging for the safety of AF ablation, 20.8% of patients had mild or moderate PV stenosis, in which the long-term effects are unknown., (Copyright © 2020 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Purpose: There is not a classification of azygos anterior cerebral artery (ACA) based on anatomical branching levels in the literature. In the present study, a classification of azygos ACA was made based on radiological imaging for a common terminology, and frequency, accompanying vascular anomalies and malformations were investigated., Methods: A total of 4913 cases who had brain CTA, MRA, contrast-enhanced MRI and DSA in January 2010-January 2020 period were screened for the study. Based on anatomical branching level, azygos ACAs were classified into four groups. Aneurysms, anomalies and malformations accompanying azygos ACA were identified. The associations of azygos ACA types with the presence of aneurysm or ACA A1 segment anomalies were investigated., Results: Azygos ACA was observed in 57 cases (29 male and 28 female) and frequency of azygos ACA was 1.16%. Average age of the cases with ACA was 56.19 ± 19.65 years. Forty-eight of the cases had type C azygos ACA, four cases type B, four cases type D and one case type A azygos ACA. A total of nine intracranial aneurysms were identified in seven of the cases (12.28%). Five of the aneurysms were located in MCA and four in distal ACA. Most common vascular anomalies accompanying azygos ACA were unilateral vertebral artery hypoplasia and ACA A1 segment hypoplasia. Azygos types did not have significant correlations with the presence of aneurysms or ACA A1 segmental anomalies (p = 0.683 and p = 0.949, respectively)., Conclusion: Azygos ACA is a rare variation, but it could be accompanied by aneurysms or other vascular anomalies.

Objective: The coronavirus disease 2019 (COVID-19) pandemic has had a significant impact on imaging utilization across practice settings. The purpose of this study was to quantify the change in the composition of inpatient imaging volumes for modality types and Current Procedural Terminology-coded groups during the COVID-19 pandemic., Methods: A retrospective study of inpatient imaging volumes in a large health care system was performed, analyzing weekly imaging volumes by modality types (radiography, CT, MRI, ultrasound, interventional radiology, nuclear medicine) in years 2020 and 2019. The data set was split to compare pre-COVID-19 (weeks 1-9) and post-COVID-19 (weeks 10-16) periods. Further subanalyses compared early post-COVID-19 (weeks 10-13) and late post-COVID-19 (weeks 14-16) periods. Statistical comparisons were performed using χ 2 and independent-samples t tests., Results: Compared with 2019, total inpatient imaging volume in 2020 post-COVID-19, early and late post-COVID-19 periods, declined by 13.6% (from 78,902 to 68,168), 16.6% (from 45,221 to 37,732), and 9.6% (from 33,681 to 30,436), respectively. By week 16, inpatient imaging volume rebounded and was only down 4.2% (from 11,003 to 10,546). However, a statistically significant shift (P < .0001) in the 2020 composition mix was observed largely comprised of radiography (74.3%), followed by CT (12.7%), ultrasound (8%), MRI (2.4%), interventional radiology (2.3%), and nuclear medicine (0.4%). Although the vast majority of imaging studies declined, few Current Procedural Terminology-coded groups showed increased trends in imaging volumes in the late post-COVID-19 period, including CT angiography chest, radiography chest, and ultrasound venous duplex., Discussion: During the COVID-19 pandemic, we observed a decrease in inpatient imaging volumes accompanied by a shift away from cross-sectional imaging toward radiography. These findings could have significant implications in planning for a potential resurgence., (Copyright © 2020 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Fast cine phase contrast magnetic resonance angiography (PC-MRA) has the potential to provide a quantitative measurement method for the diagnosis and treatment of cerebrovascular disease. To evaluation the changes of cerebral blood flow and the characteristics of artery lesion distribution in the patients of transient ischemic attacks (TIA). In all, 98 normal subjects and 106 TIA patients who underwent MRI examination within 72 h after the last symptom onset including the DWI sequence to exclude acute cerebral infarction were enrolled. The blood flow of the cranial total, the area of the internal carotid artery and vertebral artery, the average velocity, and the average blood flow were obtained and compared in normal subjects and TIA group. Analysis of Variance (ANOVA), t -test, and Kruskal-Wallis test were used for statistical assessments. The total cerebral blood flow of the TIA group and normal control group was no significant statistical difference ( P > 0.05). The total blood flow decreased with increasing age, and the TIA group was much lower than the control group. The blood flow of the right internal carotid artery in the TIA group had a significant difference compared with controls ( P < 0.05). However, the same situation did not happen in both of the left internal carotid artery and vertebral artery. Phase contrast magnetic resonance imaging has the potential to evaluate the change of cerebral blood flow in TIA patients. The decrease in the total blood flow and the symptom onset of TIA is consistent. Phase contrast magnetic resonance imaging could provide guidance to the diagnosis of TIA., Competing Interests: The authors declare no competing interests., (Copyright © 2020 Yuzhao Wang et al.)

The majority of persons with mental distress (PWMD) in India do not have access to care, and even those who seek care are pushed to attend private providers, given the weak and largely absent public mental health services framework. The aim of this study was to examine the experiences in help-seeking and with unethical health service provision among persons with mental distress in the Saharanpur and Bijnor districts of Uttar Pradesh. In-depth interviews were conducted with twenty persons with mental distress and their caregivers. Thematic analysis yielded four key findings about help-seeking: first, that it was syncretic and persistent; second, that expenditure for private care was high and often catastrophic; third, that investigations and care provided were pharmacological and predominantly irrational and excessive; and lastly, that help-seeking was abandoned. This study demonstrates that PWMD are particularly vulnerable to exploitation by private providers with illnesses that are stigmatising, poorly understood, chronic, relapsing, and disabling and that often require complex management. Responding to mental distress requires multiple empowering and interacting policy and programme initiatives that must include regulation of private and public providers, resources, and actions to strengthen public and primary mental healthcare and promotion of mental health competence in communities.

Background: We determined whether it is feasible to identify important changes in care management resulting from cardiovascular magnetic resonance (CMR) in patients who activate the primary percutaneous coronary intervention (PPCI) pathway from hospital episode data, in order to construct a composite primary outcome (hypothesised to reduce the risk of major adverse cardiac-related events, MACE) to compare patients exposed to CMR or not., Methods: We used Hospital Episode Statistics (HES) and Patient Episode Database for Wales (PEDW) to identify clinical events that reflected important changes in management in the year following the index admission in five subgroups of patients who activated the PPCI pathway recruited as part of a feasibility cohort study (n = 1655 with HES/PEDW data). For all subgroups, we identified frequency of events and time to the first event for each change in management., Results: We identified all clinical events (new diagnoses, additional diagnostic tests and procedures) except for medication prescriptions. Diagnostic tests were underestimated because most are carried out in outpatient clinics and outpatient datasets had missing procedure codes for 74% of patients (some tests done in hospital may also not be recorded). We successfully tabulated frequencies of events and distributions of times to first event for most changes in management by CMR status and in CMR / non CMR centres., Conclusions: It is feasible to identify changes in care management between patients who have / do not have CMR within relevant patient subgroups. Further work to derive a weighting algorithm is required before attempting to combine the events in a composite endpoint.

Background: Direct invasive testing in the diagnosis of stable coronary artery disease (CAD) involves high costs and relevant risks. By comparison, single-photon emission computed tomography (SPECT) and cardiac magnetic resonance imaging (CMR) are noninvasive diagnostic tests. SPECT is currently the most widely used diagnostic technique, but new medical and economic evidence favours CMR. Guidelines do not recommend one technique in preference to the other, and their use in Switzerland is poorly documented, as a scoping study by the Swiss Medical Board reported. We aimed at a quantitative and qualitative analysis of the use of these diagnostic techniques in Swiss hospitals., Methods: We contacted nine Swiss hospitals to obtain the number of SPECT/CMR investigations used to diagnose stable CAD in 2014&ndash;2016 and submitted a questionnaire to investigate the advantages and limitations of the two imaging techniques. In addition, two experts in SPECT and CMR, respectively, at two university hospitals were interviewed, using open questions., Results: Data were obtained from 8 hospitals, and 22 questionnaires were returned. In Switzerland, both techniques have been implemented very differently in different hospitals, but the overall number of diagnostic procedures has increased. The questionnaires reported lower scores for CMR regarding the availability of the scans, contraindications and the suitability of the technique for the diagnosis of CAD. The experts described potential conflicts of interest in some institutions, depending on how the cardiology and radiology departments collaborated, and highlighted the debated results of studies comparing CMR with SPECT for the diagnosis of CAD. The main conclusion drawn from the interviews was the recommendation of a patient-centred evaluation., Conclusion: The use of SPECT versus CMR in Switzerland for the diagnosis of stable CAD is heterogeneous, but reflects the guidelines, which do not distinguish between the two diagnostic techniques. Expert opinions underlined that discussion should not be so much about the choice of the diagnostic modality but about how a clinical question in a patient can best be answered.

Background Autosomal dominant polycystic kidney disease (ADPKD) affects one in 400 to one in 1000 individuals; 10%-11% of these individuals have intracranial aneurysms. The frequency and patterns of screening for intracranial aneurysms have not been defined. Purpose To evaluate different MR angiography screening and surveillance strategies for unruptured intracranial aneurysms in patients with ADPKD. Materials and Methods A Markov decision-analytic model was constructed accounting for both costs and outcomes from a societal perspective. Five different management strategies were evaluated: (a) no screening for intracranial aneurysm, (b) one-time screening with annual MR angiography follow-up in patients with intracranial aneurysm, (c) MR angiographic screening every 5 years with endovascular treatment in detected intracranial aneurysm, (d) MR angiography screening every 5 years with annual MR angiography follow-up in patients with intracranial aneurysm, and (e) MR angiography screening every 5 years with biennial follow-up in patients with intracranial aneurysm. One-way, two-way, and probabilistic sensitivity analyses were performed. Results Base case calculation shows that MR angiography screening of patients with ADPKD every 5 years and annual follow-up in patients with detected intracranial aneurysm is the optimal strategy (cost, $19 839; utility, 25.86 quality-adjusted life years), which becomes more favorable as the life expectancy increases beyond 6 years. The conclusion remains robust in probabilistic and one-way sensitivity analyses. When the prevalence of intracranial aneurysms is greater than 10%, annual rupture risk is 0.35%-2.5%, and the rate of de novo aneurysm detection is lower than 1.8%, MR angiography screening every 5 years with annual MR angiography follow-up is the favorable strategy. Conclusion Screening for intracranial aneurysms with MR angiography in patients with autosomal dominant polycystic kidney disease is cost-effective. Repeat screening every 5 years should be performed after a negative initial study. Annual surveillance MR angiography is optimal in patients with detected, incidental intracranial aneurysm, and treatment may be considered in patients with growing, high-risk aneurysms. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Anzai in this issue.

Objectives: To investigate the diagnostic performance of dynamic fetal cardiac magnetic resonance imaging (MRI), using a MR-compatible Doppler ultrasound (DUS) device for fetal cardiac gating, in differentiating fetuses with congenital heart disease from those with a normal heart, and to compare the technique with fetal echocardiography., Methods: This was a prospective study of eight fetuses with a normal heart and four with congenital heart disease (CHD), at a median of 34 (range, 28-36) weeks' gestation. Dynamic fetal cardiac MRI was performed using a DUS device for direct cardiac gating. The four-chamber view was evaluated according to qualitative findings. Measurements of the length of the left and right ventricles, diameter of the tricuspid and mitral valves, myocardial wall thickness, transverse cardiac diameter and left ventricular planimetry were performed. Fetal echocardiography and postnatal diagnoses were considered the reference standards., Results: Direct cardiac gating allowed continuous triggering of the fetal heart, showing high temporal and spatial resolution. Both fetal cardiac MRI and echocardiography in the four-chamber view detected pathological findings in three of the 12 fetuses. Qualitative evaluation revealed overall consistency between echocardiography and MRI. On both echocardiography and MRI, quantitative measurements revealed significant differences between fetuses with a normal heart and those with CHD with respect to the length of the right (P < 0.01 for both) and left (P < 0.01 for both) ventricles and transverse cardiac diameter (P < 0.05 and P < 0.01, respectively). Tricuspid valve diameter on cardiac MRI was found to be significantly different in healthy fetuses from in those with CHD (P < 0.05)., Conclusions: For the first time, this study has shown that dynamic fetal cardiac MRI in the four-chamber view, using external cardiac gating, allows evaluation of cardiac anatomy and diagnosis of congenital heart disease in agreement with fetal echocardiography. Dynamic fetal cardiac MRI may be useful as a second-line investigation if conditions for fetal echocardiography are unfavorable. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd., (Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.)

Objective: To assess the inter-technique agreement of relative cerebral blood volume (rCBV) measurements obtained using T1- and T2*-perfusion MRI on 3T scanner in glioma patients., Methods: A total of 49 adult patients with gliomas underwent both on T1- and T2*-perfusion in the same scanning session, and rCBV maps were estimated using both methods. For the quantitative analysis; Two independent observers recorded the rCBV values from the tumor as well as contralateral brain tissue from both T1- and T2*-perfusion. Inter-observer and inter-technique rCBV measurement agreement were determined by using 95% Bland-Altman limits of agreement and intra-class correlation coefficient (ICC) statistics., Results: Qualitative analysis of the conventional and perfusion images showed that 16/49 (32.65%) tumors showed high susceptibility, and in these patients T2*-perfusion maps were suboptimal. Bland-Altman plots revealed an agreement between two independent observers recorded rCBV values for both T1- and T2*-perfusion. The ICC demonstrated strong agreement between rCBV values recorded by two observers for both T2* (ICC = 0.96, p = 0.040) and T1 (ICC = 0.97, p = 0.026) perfusion and similarly, good agreement was noted between rCBV estimated using two methods (ICC = 0.74, P<0.001). ROC analysis showed that rCBV estimated using T1- and T2*-perfusion methods were able to discriminate between grade-III and grade-IV tumors with AUC of 0.723 and 0.767 respectively. Comparison of AUC values of two ROC curves did not show any significant difference., Conclusions: In the current study, T1- and T2*-perfusion showed similar diagnostic performance for discrimination of grade III and grade IV gliomas; however, T1-perfusion was found to be better for the evaluation of tumors with intratumoral hemorrhage, postoperative recurrent tumors, and lesions near skull base. We conclude that T1-perfusion MRI with a single dose of contrast could be used as an alternative to T2*-perfusion to overcome the issues associated with this technique in brain tumors for reliable perfusion quantification., Competing Interests: The authors have read the journal's policy and the authors of this manuscript have the following competing interests: IS and MVC are paid employees of Philips Health Systems and Philips Health Tech Asia Pacific. There are no patents, products in development or marketed products associated with this research to declare. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Murine models are used in a wide range of renal studies, from those assessing the role of molecular and genetic factors in mammalian development and congenital diseases, to developing and screening new therapeutics. In studies of these models, magnetic resonance imaging (MRI) techniques are playing an ever increasing role in characterizing both structural and functional changes of the kidneys. This chapter details the use of MRI for this purpose-from acquisition to image analysis. An overview of the wide range of characterization that can be performed by this technology is first given. Next, basic image analysis and more advanced image processing techniques are detailed. The utility of MR for characterizing anatomical and physiological properties of murine models of disease is supplemented with data from our work studying polycystic kidney disease., (© 2019 Elsevier Inc. All rights reserved.)

Objective: Dural arteriovenous fistulas (DAVFs) at the petrous apex are rare but may cause subarachnoid hemorrhage (SAH) or severe brainstem edema. This study aimed to summarize their clinical features and discuss the classification., Methods: During a 15-year period, 64 consecutive patients with DAVF at the petrous apex were reviewed. According to their angioarchitecture, these cases were classified as follows: type I, no venous ectasia (48.4%); type II, venous ectasia but with normal vein proximal to the fistula (29.7%); and type III, venous ectasia at the site of the fistula (21.9%)., Results: There were 53 men and 11 women included. Presented symptoms were SAH in 8 patients (12.5%), nonhemorrhagic neurologic defects (NHNDs) in 53 patients (82.8%), and no symptoms in 3 patients (4.7%). There were 49 patients who received transarterial embolization, 8 patients who received microsurgery, and 7 patients who received embolization and microsurgery. Complications occurred in 9 patients (14.1%), including transient cranial nerve palsy (4.7%), rebleeding (6.3%), and respiratory failure (3.1%). Of the type I patients, 96.77% presented with NHNDs and 77.42% presented with infratentorial drainage. However, SAH occurred more often in type II (21.05%)/type III cases (28.57%), and most patients carried a supratentorial drainage (63.16% and 85.71%, respectively). In different types of DAVFs, the necessity for embolization combined with microsurgery (6.45% in type I, 10.53% in type II, 21.43% in type III) and the occurrence of rebleeding complications (0% in type I, 10.53% in type II, and 14.29% in type III) were varied., Conclusions: Petrous apex DAVFs carried a high risk of embolization-related complications. Based on the vascular architecture, this classification may reflect their clinical features and provide some advice on the treatment of DAVFs at the petrous apex., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Purpose: The purpose of this study was to evaluate extremely rare cases of supradiaphragmatic origin of the renal artery, with magnetic resonance (MR) imaging findings., Methods: The study included 9 patients diagnosed with supra-diaphragmatic originating renal artery between 2010 and 2017. The patients were 7 females and 2 males with a mean age of 58.25 years (range, 41-71 years). MR imaging was applied to all patients., Results: In 2 patients, lumen loss was of a moderate degree, and mild in 3 patients. Renal artery stenosis was not observed in the remaining 4 patients. None of the patients had advanced luminal stenosis. The distance of the renal arteries to the diaphragmatic crus was 24 mm at the longest and 8 mm at the shortest. Congenital anomaly was found in 6 patients. Of the 9 patients, 7 had concomitant hypertension, and 2 had no history of hypertension., Conclusions: The anomaly of supradiaphragmatic origin of the renal artery is rare but may be associated with renal artery stenosis, which may then result in hypertension. The clinician should investigate renal artery origin anomalies and renal artery compression syndrome in hypertensive cases where the cause cannot be explained., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Inadequate ablation lesion formation may be responsible for post-ablation ventricular tachycardia (VT) recurrences.We aimed to evaluate whether visualisation of radiofrequency (RF) lesion size by cardiac magnetic resonance imaging (CMR) has any role in predicting adequacy of lesion and in estimating outcome.Retrospective pilot studyNine consecutive patients (8 male, age 60 ± 13 years) underwent ablation for sustained VT because of ischemic scar were evaluated for pre- and post-procedure scar tissue by CMR to characterize ablation lesions. Microvascular obstruction (MVO) surrounded by late gadolinium enhancement was defined as irreversible RF lesion. All patients were followed for at least 6 months for recurrences.Five of the patients had previous inferior myocardial infarction (MI), whereas remaining 4 had anterior MI. Acute procedural success, as defined by termination of the arrhythmia without recurrence in 30 minutes, was attained in all patients. Contrast enhancement and wall motion abnormality in presumed infarction area were confirmed by pre-ablation CMR images. MVO was detected at the reported ablation site in 6/9 patients, all arrhythmia- and symptom-free at median 24 months (range 8-38 months) follow-up. In remaining 3 patients who had VT recurrence (clinical VT in 2, sustain VT with a new morphology in 1), MVO was not detected despite achievement of acute procedural success. There was no correlation with pre-ablation scar size and clinical arrhythmia recurrence.CMR is a useful imaging modality to guide ablation procedures by detecting scar tissue. Additionally MVO seen by post-procedural imaging may be related to adequacy of RF ablation lesions and may correlate with clinical outcome.

Acute myocardial infarction (AMI) is recognized as being a life-threatening event. Both microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH) have been recognized as poor prognostic factors in myocardial infarct (MI) since they adversely affect left ventricular remodeling. MVO refers to small vessels changes that prevent adequate tissue perfusion despite revascularization whereas IMH is a severe form of MVO. A limited number of studies have demonstrated the segmental intervention time and the clinical factors in the presence of MVO and IMH. Therefore, we aimed in this study to determine the correlations of the intervention-associated and clinical indexes with malignant cardiovascular magnetic resonance (CMR) signs in patients with AMI.Sixty-three patients with STEMI who underwent primary percutaneous coronary intervention (PPCI) within 12 hours were included in this study. A 3.0-T CMR scan was prescribed, and the subsequent image analysis was conducted by researchers blinded to the clinical index results. Late-gadolinium enhancement (LGE) and T2* sequences were mainly used for MVO and IMH identification and quantification.Patients exhibiting both MVO and IMH had the highest level of LGE (P < .001) and were significantly more frequently assigned to a pre-PPCI thrombolysis in myocardial infarction (TIMI) flow class of 0 (n=25, 89.3%). The MVO size correlated positively with the IMH size (r = 0.81, P < .01). A pre-PPCI TIMI flow class of 0 was found to reliably predict the presence of IMH (P < .001). Patients who received the intervention 4 to 6 hours after MI onset were more likely to exhibit MVO and IMH, although this trend was not statistically significant.We showed in our study that both MVO and IMH correlated with the degree of AMI and the pre-PPCI coronary flow, and both tended to occur more frequently in cases involving an interval of 4 to 6 hours between the onset of MI and the intervention. CMR is a reliable method for assessing MVO and IMH and its imaging features following gadolinium administration are characteristic. These findings stress the importance of using CMR in evaluating and improving the outcome of the medical management.

Background and Aim: Carotid artery stenosis is one of the major causes of transient ischemic attack (TIA) and acute ischemic stroke (IS), and carotid surgery and stenting are used to reduce the risk of ipsilateral IS. However, the adherence to the recommendation of carotid imaging in clinical practice has not been well studied. We analyzed proportions of carotid imaging and determinants for its non-use in patients with TIA and IS with respect to baseline demographics, risk factors, hospital characteristics, and geographical region., Patients and Methods: Hospital-based data on TIA and IS events, registered from July 2011 to June 2013, were obtained from the Swedish Stroke Register (Riksstroke). Carotid imaging diagnostics included carotid Doppler ultrasound and computed tomography angiography., Results: Carotid imaging was performed in 70% (10 545/15 021) of patients with TIA and 54% (23 772/44 075) of patients with IS. The most significant independent determinants for not undergoing carotid imaging were, in patients with TIA: age ≥85 year (odds ratio (OR), 7.3; 95% confidence interval (CI), 6.4-8.4) and a history of stroke (OR, 2.3; 95% CI, 2.1-2.5); and in patients with IS: age ≥85 year (OR, 9.8; 95% CI, 9.0-10.6), age 75-84 year (OR, 2.5; 95% CI, 2.3-2.7), and reduced level of consciousness at admission (OR, 3.4; 95% CI, 3.1-3.6). Care at a University hospital and in a stroke unit increased the likelihood of carotid imaging. There were substantial regional variations regarding proportions of carotid imaging., Conclusion: Carotid imaging appears to be underused in patients with TIA and IS. Opportunities of secondary stroke prevention with carotid interventions are likely missed., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: To assess for changes in emergency department (ED) utilization of neuroimaging in Medicare fee-for-service beneficiaries from 1994 to 2015., Methods: Using Medicare Physician Supplier Procedure Summary Master Files, annual ED volumes of head computed tomography (CT), magnetic resonance (MR), and carotid duplex ultrasound (CDUS) were assessed from 1994 through 2015. Annual volumes of head CT angiography (CTA), neck CTA, head MR angiography (MRA), and neck MRA studies were assessed from 2001 (first year of unique reporting codes) through 2015. Longitudinal population-based utilization rates were calculated using annual Medicare Part B enrollment, and utilization rates were normalized annually per 1000 ED visits., Results: From 1994 through 2015, ED neuroimaging utilization rates per 1000 ED visits increased 660% overall (compound annual growth rate [CAGR] 9%); 529% for head CT (CAGR 9%); 1451% for head MRI (CAGR 14%); and by 104% for CDUS (CAGR 3%). From 2001 to 2015, rates increased 14,600% (CAGR 43%) and 17,781% (CAGR 45%) for head and neck CTA, respectively, and 525% (CAGR 14%) and 667% (CAGR 16%) for head and neck MRA, respectively. Trends were similar when volumes were normalized for annual Medicare fee-for-service enrollment. Non-contrast head CT was the most common imaging modality throughout the study period (86% of annual neuroimaging volume in 1994; 89% in 2015)., Conclusions: In Medicare beneficiaries, neuroimaging utilization in the ED grew unabated from 1994 through 2015, with growth of head and neck CTA far outpacing other modalities. Non-contrast head CT remains by far the dominant ED neuroimaging examination., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: In arterial spin labeling (ASL), the cardiac cycle might adversely influence signal-stability by varying the amount of label created, labeling efficiency and/or transport times. Due to the long labeling duration in pseudo-Continuous ASL (pCASL), the blood labeled last contributes most to the ASLsignal. The present study investigated, using numerical simulations and in vivo experiments, the effect of the cardiac cycle on pCASL, thereby focusing on the end-of-labeling., Materials and Methods: In the in vivo experiments the end-of-labeling was timed to a specific cardiac phase while a long labeling duration of >7 s was used to isolate the influence of the lastly labeled spins on ASL-signal stability., Results: Simulations showed dependence of the ASL-signal on the cardiac phase of the end-of-labeling, and that the variation in signal was more pronounced at lower heart rates. The ASL-signal variation was small (~4%), but could be effectively reduced by simulated end-of-labeling triggering. In vivo, no difference in mean CBF (p = 0.58) nor in CBF temporal-STD (p = 0.44) could be detected between triggered and non-triggered acquisitions., Conclusion: Influence of the cardiac cycle on pCASL-signal stability is small and triggering the start-of-labeling and end-of-labeling can be considered not to have practical implications to improve stability.

Objective: The purpose of this work is to evaluate the repeatability of a compressed sensing (CS) accelerated multi-contrast carotid protocol at 3 T., Materials and Methods: Twelve volunteers and eight patients with carotid disease were scanned on a 3 T MRI scanner using a CS accelerated 3-D black-blood multi-contrast protocol which comprises T 1 w, T 2 w and PDw without CS, and with a CS factor of 1.5 and 2.0. The volunteers were scanned twice, the lumen/wall area and wall thickness were measured for each scan. Eight patients were scanned once, the inter/intra-observer reproducibility of the measurements was calculated., Results: In the repeated volunteer scans, the interclass correlation coefficient (ICC) for the wall area measurement using a CS factor of 1.5 in PDw, T 1 w and T 2 w were 0.95, 0.81, and 0.97, respectively. The ICC for lumen area measurement using a CS factor of 1.5 in PDw, T 1 w and T 2 w were 0.96, 0.92, and 0.96, respectively. In patients, the ICC for inter/intra-observer measurements of lumen/wall area, and wall thickness were all above 0.81 in all sequences., Conclusion: The results show a CS accelerated 3-D black-blood multi-contrast protocol is a robust and reproducible method for carotid imaging. Future protocol design could use CS to reduce the scanning time.

The past decade has witnessed the rapid development of new MRI technology for vessel wall imaging. Today, with advances in MRI hardware and pulse sequences, quantitative MRI of the vessel wall represents a real alternative to conventional qualitative imaging, which is hindered by significant intra- and inter-observer variability. Quantitative MRI can measure several important morphological and functional characteristics of the vessel wall. This review provides a detailed introduction to novel quantitative MRI methods for measuring vessel wall dimensions, plaque composition and permeability, endothelial shear stress and wall stiffness. Together, these methods show the versatility of non-invasive quantitative MRI for probing vascular disease at several stages. These quantitative MRI biomarkers can play an important role in the context of both treatment response monitoring and risk prediction. Given the rapid developments in scan acceleration techniques and novel image reconstruction, we foresee the possibility of integrating the acquisition of multiple quantitative vessel wall parameters within a single scan session.

Objective: This study aims to explore the relationship between plaque surface morphology and neovascularization using a high temporal and spatial resolution 4D contrast-enhanced MRI/MRA sequence., Materials and Methods: Twenty one patients with either recent symptoms or a carotid artery stenosis ≥40% were recruited in this study. Plaque surface morphology and luminal stenosis were determined from the arterial phase MRA images. Carotid neovascularization was evaluated by a previously validated pharmacokinetic (PK) modeling approach. K trans (transfer constant) and v p (partial plasma volume) were calculated in both the adventitia and plaque., Results: Image acquisition and analysis was successfully performed in 28 arteries. Mean luminal stenosis was 44% (range 11-82%). Both adventitial and plaque K trans in ulcerated/irregular plaques were significantly higher than smooth plaques (0.079 ± 0.018 vs. 0.064 ± 0.011 min -1 , p = 0.02; 0.065 ± 0.013 vs. 0.055 ± 0.010 min -1 , p = 0.03, respectively). Positive correlations between adventitial K trans and v p against stenosis were observed (r = 0.44, p = 0.02; r = 0.55, p = 0.01, respectively)., Conclusion: This study demonstrates the feasibility of using a single sequence to acquire both high resolution 4D CE-MRA and DCE-MRI to evaluate both plaque surface morphology and function. The results demonstrate significant relationships between lumen surface morphology and neovascularization.

Aim: Neoadjuvant chemoradiotherapy for locally advanced rectal cancer aims to downstage prior to definitive management. Repeat imaging assessment of the tumour post-therapy has implications for treatment. Our aim was to assess if the inferior mesenteric vein (IMV) diameter measured on CT can be used as a surrogate marker for evaluation of tumour response to neoadjuvant treatment., Method: IMV diameter was assessed in patients with and without locally advanced rectal cancer, pre- and post-radiotherapy, to ascertain if IMV diameter is a surrogate marker of tumour response., Results: IMV diameter was 5.9 mm in patients with rectal cancer vs 4.7 mm in patients without (P = 0.0001). The baseline IMV diameter was significantly higher for cases with local lymphadenopathy [N0 5.2 mm vs N1/2 6 mm (P = 0.0059)] and extramural venous invasion (EMVI) [negative 5.4 mm vs positive 6.4 mm (P = 0.0001)]. Post-radiotherapy there was a significant decrease in the IMV diameter in cases with treatment response compared to non-responders: the percentage change in IMV diameter was a 17.54% decrease vs 1.39% increase (P = 0.0001). These results were reproduced on comparing between magnetic resonance tumour regression grades using ANOVA (P = 0.0001). There was also a significant decrease in IMV diameter when assessing lymph node (LN) and EMVI response vs non-responders (P = 0.0001 and 0.0001 respectively)., Conclusion: Patients with rectal cancer have a dilated IMV compared with patients without rectal cancer. We confirm that IMV diameter is a potential surrogate marker of LN status and EMVI at baseline. IMV diameter is also a marker of tumour, LN and EMVI response to chemoradiotherapy., (Colorectal Disease © 2017 The Association of Coloproctology of Great Britain and Ireland.)

Objective: This research utilizes magnetic resonance angiography (MRA) to identify arterial locations during the parametric evaluation of concentration time curves (CTCs), and to prevent shape distortions in arterial input function (AIF)., Materials and Methods: We carried out cluster analysis with the CTC parameters of voxels located within and around the middle cerebral artery (MCA). Through MRA, we located voxels that meet the AIF criteria and those with distorted CTCs. To minimize partial volume effect, we re-scaled the time integral of CTCs by the time integral of venous output function (VOF). We calculated the steady-state value to area under curve ratio (SS:AUC) of VOF and used it as a reference in selecting AIF. CTCs close to this reference value (selected AIF) and those far from it were used (eliminated AIF) to compute cerebral blood flow (CBF)., Results: Eliminated AIFs were found to be either on or anterior to MCA, whereas selected AIFs were located superior, inferior, posterior, or anterior to MCA. If the SS:AUC of AIF was far from the reference value, CBF was either under- or over-estimated by a maximum of 41.1 ± 14.3 and 36.6 ± 19.2%, respectively., Conclusion: MRA enables excluding voxels on the MCA during cluster analysis, and avoiding the risk of shape distortions.

Rationale and Objectives: Blunt cerebrovascular injury (BCVI) is uncommon, but delayed detection can have disastrous consequences. The Denver criteria are the most commonly used screening criteria. We aim to examine the utilization of screening criteria in the emergency department (ED) of our institution and assess whether patients with risk factors were imaged., Materials and Methods: A survey questionnaire was sent out to radiologists in a large academic institution. A search was performed in the database on the use of CT angiography (CTA) and MR angiography (MRA) among patients with risk factors in the last 11 years., Results: The survey was sent to 173 radiologists, with 41 responses (35 complete). Most of the physicians (30 out of 35) surveyed selected CTA as their preferred modality to screen for BCVI, whereas the remaining physicians selected MRA. None of the respondents reported routine use of Denver screening criteria or grading scale in their readouts. Only five respondents selected risk factors in the Denver criteria correctly. In the institution search, among the 1331 patients with blunt trauma and risk factors for BCVI, 537 underwent at least one angiographic study (40.3%). There was an increase in the screening rate after February 2010 in all risk factors, but only statistically significant among patients with foramen transversarium fractures and C1-C3 fractures., Conclusions: Both the Denver screening criteria and grading scale of vascular injury have been underutilized in the ED for patients with risk factors. Greater awareness and utilization of imaging can potentially result in decreased incidence of subsequent stroke in patients with blunt injury., (Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Objective: The aim of this study was to investigate the association between perfusion parameters on MRI performed before treatment and survival outcome (disease-free survival [DFS], disease-specific survival [DSS]) in patients with triple-negative breast cancer (TNBC)., Materials and Methods: Sixty-one patients (median age, 50 years; age range, 27-77 years) with TNBC (tumor size on MRI: median, 25.5 mm; range, 11.0-142.0 mm) were included. We analyzed clinical and pathologic variables and MRI parameters. Cox proportional hazards models were used to determine associations with survival outcome., Results: The median follow-up time was 46.1 months (range, 13.9-58.4 months). Eleven of 61 (18.0%) patients had events (i.e., local, regional, or distant recurrence or contralateral breast cancer) and seven (11.5%) died of breast cancer. Among the pretreatment variables, a larger tumor size on MR images (hazard ratio [HR] = 1.024, p = 0.003) was associated with worse DFS at univariate analysis. In multivariate pretreatment models for DSS, a higher fractional volume of extravascular extracellular space per unit volume of tissue (v e ) value (HR = 1.658, p = 0.038), higher peak enhancement (HR = 1.843, p = 0.018), and a larger tumor size on MR images (HR = 1.060, p = 0.001) were associated with worse DSS. In multivariate posttreatment models, a larger pathologic tumor size (HR for DFS, 1.074 [p = 0.005]; HR for DSS, 1.050 [p = 0.042]) and metastasis in surgically resected axillary lymph nodes (HR for DFS, 5.789 [p = 0.017]; HR for DSS, 23.717 [p = 0.005]) were associated with worse survival outcome., Conclusion: A higher v e value, higher peak enhancement, and larger tumor size of the primary tumor on pretreatment MRI were independent predictors of worse DSS in patients with TNBC.

Aim: To investigate the ability of arterial spin labelling (ASL) perfusion parameters to distinguish high-grade from low-grade gliomas., Materials and Methods: The PubMed and EMBASE databases were systematically searched for relevant articles published up to September 2015. Studies that evaluated both high- and low-grade gliomas using ASL were included. The random effect model was used to calculate the standardised mean difference (SMD) of maximum mean absolute tumour blood flow values (aTBF max , aTBF mean ) and maximum mean relative tumour blood flow (rTBF max , rTBF mean ) between high- and low-grade gliomas., Results: Nine studies encompassing 305 patients with high- and low-grade gliomas, met all inclusion and exclusion criteria and were included in the study. Compared with low-grade gliomas, high-grade gliomas had a significant increase in all ASL perfusion values: aTBF max (SMD=0.70, 95% confidence interval [CI]: 0.22-1.19, p=0.0046); aTBF mean (SMD=0.86, 95% CI: 0.2-1.52, p=0.01); rTBF max (SMD=1.08, 95% CI: 0.54-1.63, p=0.0001) and rTBF mean (SMD=0.88, 95% CI: 0.35-1.4, p=0.0011)., Conclusions: The current study results indicate that tumour blood flow from ASL differs significantly with respect to the glioma grade. Despite some limitations, there is evidence that ASL may be useful to distinguish high- and low-grade gliomas. Further larger-scale studies are necessary to examine the utility of ASL to distinguish tumour grade., (Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Background: Stroke and other non-communicable diseases are important emerging public health concerns in sub-Saharan Africa where stroke-related mortality and morbidity are higher compared to other parts of the world. Despite the availability of evidence-based acute stroke interventions globally, uptake in low-middle income countries (LMIC) such as Ghana is uncertain. This study aimed to identify and evaluate available acute stroke services in Ghana and the extent to which these services align with global best practice., Methods: A multi-site, hospital-based survey was conducted in 11 major referral hospitals (regional and tertiary - teaching hospitals) in Ghana from November 2015 to April 2016. Respondents included neurologists, physician specialists and medical officers (general physicians). A pre-tested, structured questionnaire was used to gather data on available hospital-based acute stroke services in the study sites, using The World Stroke Organisation Global Stroke Services Guideline as a reference for global standards., Results: Availability of evidence-based services for acute stroke care in the study hospitals were varied and limited. The results showed one tertiary-teaching hospital had a stroke unit. However, thrombolytic therapy (thrombolysis) using recombinant tissue plasminogen activator for acute ischemic stroke care was not available in any of the study hospitals. Aspirin therapy was administered in all the 11 study hospitals. Although eight study sites reported having a brain computed tomographic (CT) scan, only 7 (63.6%) were functional at the time of the study. Magnetic resonance imaging (MRI scan) services were also limited to only 4 (36.4%) hospitals (only functional in three). Acute stroke care by specialists, especially neurologists, was found in 36.4% (4) of the study hospitals whilst none of the study hospitals had an occupational or a speech pathologist to support in the provision of acute stroke care., Conclusion: This study confirms previous reports of limited and variable provision of evidence based stroke services and the low priority for stroke care in resource poor settings. Health policy initiatives to enhance uptake of evidence-based acute stroke services is required to reduce stroke-related mortality and morbidity in countries such as Ghana.

Objectives: This study sought to test the hypothesis that a vectorcardiographic parameter, the QRS vector magnitude (QRSVm), can risk stratify those patients at risk for sustained spontaneous ventricular arrhythmias (VAs) or ventricular arrhythmia inducibility (VAI) in a large cohort of patients with tetralogy of Fallot (TOF)., Background: Patients with TOF have an increased risk of VAs, but predicting those at risk can often be challenging., Methods: Blinded retrospective analyses of 177 TOF patients undergoing pulmonary valve replacement (PVR) between 1997 and 2015 were performed. VAI was evaluated by programmed electrical stimulation in 48 patients. QRS intervals and QRSVm voltage measurements were assessed from resting 12-lead electrocardiograms, and risk of VA was determined. Clinical characteristics, including imaging and cardiac catheterizations, were used for other modality comparisons., Results: Sustained spontaneous VA occurred in 12 patients and inducible VA in 18 patients. Age and QRSVm were significant univariate predictors of VA. QRSVm was the only independent predictor of VAI (p < 0.001). Using a root mean square QRS value of 1.24 mV, the positive and negative predictive values were 47.9% and 97.8%, respectively, for spontaneous sustained VA. For VAI, using a QRSVm cutoff of 1.31 mV, positive and negative predictive values were 63.0% and 95.3%, respectively., Conclusions: In TOF patients undergoing PVR, older age was associated with increased spontaneous VA risk. Lower QRSVm predicted spontaneous VA or VAI risk with high negative predictive values. QRSVm is the only independent predictor of VAI. These clinical features may help further risk stratify TOF patients requiring therapies to prevent sudden death., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Aim: To determine the accuracy of the susceptible vessel sign (SVS) in the detection of arterial occlusion and its clinical implication in acute ischaemic stroke., Materials and Methods: Consecutive ischaemic stroke patients who underwent magnetic resonance imaging (MRI) with susceptibility-weighted imaging (SWI) within 24 hours of symptom onset or time last-seen-well were included. Two independent neuroradiologists reviewed the SWI for evidence of the SVS. Admission stroke severity was determined by the National Institute of Health Stroke Scale (NIHSS) scores, and poor clinical outcome was defined by a 3-months modified Rankin scale (mRS) score >2., Results: The SVS was identified in 26 (12%) of 213 patients with substantial inter-reviewer agreement. The SVS had 99% specificity, 88% negative predictive value (NPV), 51% sensitivity, and 92% positive predictive value (PPV) for detection of acute arterial occlusions. In consecutive stroke patients, the presence of SVS was associated with higher admission NIHSS scores (median 9 versus 3, p<0.001), arterial occlusion (92% versus 12%, p<0.001), larger infarct volume (162±180 ml versus 25±48 ml, p=0.001), and higher rate of poor clinical outcome at 3-months follow-up (58% versus 25%, p=0.001). In the subset of patients with acute arterial occlusion (n=47), the SVS was associated with higher admission NIHSS scores (median of 10 versus 3, p=0.038) and larger infarct volumes (173±184 ml versus 76±112 ml, p=0.034)., Conclusions: The SVS is a highly specific sign of occlusive arterial thrombus, and is associated with larger infarct volume and more severe presentation in a series of consecutive stroke patients, as well as in the subgroup of patients with acute arterial occlusion., (Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Background: The prevalence of asymptomatic unruptured intracranial aneurysms (AUIA) in a Southeast Asian population has not been previously studied. Knowing the disease burden and population at risk can assist us in making informed decisions when managing AUIAs. We aimed to determine if the local prevalence of AUIAs differed from other populations in the published literature., Methods: Magnetic resonance angiography radiology reports and images for 4572 patients between January 2013 and January 2014 were reviewed for AUIAs., Results: The overall prevalence of AUIAs was 3.5% (160/4572). It was significantly higher in women (4.5%) compared with men (2.6%) (P < 0.001). The mean aneurysm size was 3.2 ± 1.7 mm. Of the aneurysms, 88.5% (146/165) measured less than 5 mm, 9.7% (16/165) measured 5-9 mm, and 1.8% (3/165) measured more than 9 mm. Most of the aneurysms were located in the cavernous segment (72/165, 43.6%) and ophthalmic segment (34/165, 20.6%) of the internal carotid artery, followed by the middle cerebral artery (16/165, 9.7%). The posterior circulation contributed 9.1% (15/165) of the AUIAs. During the study period, 1 aneurysm ruptured and the rest of the aneurysms did not show any growth., Conclusions: In this large cohort of a Southeast Asian population, the prevalence of AUIA was 3.5%. Most of the AUIAs were less than 5 mm and did not require intervention at time of discovery and did not progress within the year of follow-up., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Introduction: Cerebellar cortical infarct cavities are a newly recognised entity associated with atherothromboembolic cerebrovascular disease and worse physical functioning. We aimed to investigate the relationship of cerebellar cortical infarct cavities with symptomatic vertebrobasilar ischaemia and with vascular risk factors., Methods: We evaluated the MR images of 46 patients with a recent vertebrobasilar TIA or stroke and a symptomatic vertebral artery stenosis ≥50 % from the Vertebral Artery Stenting Trial (VAST) for the presence of cerebellar cortical infarct cavities ≤1.5 cm. At inclusion in VAST, data were obtained on age, sex, history of vertebrobasilar TIA or stroke, and vascular risk factors. Adjusted risk ratios were calculated with Poisson regression analyses for the relation between cerebellar cortical infarct cavities and vascular risk factors., Results: Sixteen out of 46 (35 %) patients showed cerebellar cortical infarct cavities on the initial MRI, and only one of these 16 patients was known with a previous vertebrobasilar TIA or stroke. In patients with symptomatic vertebrobasilar ischaemia, risk factor profiles of patients with cerebellar cortical infarct cavities were not different from patients without these cavities., Conclusion: Cerebellar cortical infarct cavities are seen on MRI in as much as one third of patients with recently symptomatic vertebral artery stenosis. Since patients usually have no prior history of vertebrobasilar TIA or stroke, cerebellar cortical infarct cavities should be added to the spectrum of common incidental brain infarcts visible on routine MRI.

Purpose: To determine the incidence of actionable findings on contrast-enhanced magnetic resonance angiography (MRA) scans performed for the primary diagnosis of pulmonary embolism (PE)., Materials and Methods: This was a HIPAA-compliant and IRB-approved single center, retrospective study of consecutive series of patients evaluated with contrast-enhanced MRA for PE. The final radiology report of each MRA was reviewed. All technically adequate negative exams were included in the analysis. The findings were divided into three types: those requiring further action (actionable-Type 1) those not requiring follow-up (non-actionable-Type 2) and normal exams. We compared our results with the literature regarding the use of computed tomographic angiography (CTA) in this scenario using Fisher's exact test., Results: 580 MRA scans for PE were performed. There were 561/580 (97%) technically adequate exams. Of these, 514/580 (89%) were negative and 47/580 (8%) were positive for PE. In the PE negative group of 514 exams, Type 1 findings were identified in 85/514 (17%), 188/514 (36%) cases were Type 2 and 241/514 (47.0%) were Type 3. There was no significant difference between the incidence of Type 1 and the combination of Type 2 and Type 3 findings on MRA and the reported incidence of actionable findings derived from CTA negative exams for PE (p<0.5)., Conclusion: MRA as a first-line test for PE can identify actionable findings in those patients without PE, with an incidence similar to that reported in the literature for CTA., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Introduction: This study aims to review the diagnostic performance of computed tomography (CT) and magnetic resonance imaging (MRI) in symptomatic dural arteriovenous fistula (DAVF)., Methods: EMBASE, PubMed, and Cochrane Library were searched until April 2015 for studies which compared CT, MRI, or both with angiography for the detection of DAVF. The diagnostic performances of MRI and CT were indirectly compared using modality as a covariate in the analysis., Results: Thirteen studies met our inclusion criteria. MRI had a sensitivity of 0.90 (95 % confidence interval (CI) = 0.83-0.94) and specificity of 0.94 (95 % CI = 0.90-0.96). CT had a sensitivity of 0.80 (95 % CI = 0.62-0.90) and specificity of 0.87 (95 % CI = 0.74-0.94). MRI showed better diagnostic performance than CT (p = 0.02). Contrast medium use and time-resolved MR angiography did not improve MRI diagnostic performance (p = 0.31 and 0.44, respectively)., Conclusion: Both CT and MRI had good diagnostic performance. MRI was better than CT on the detection of symptomatic intracranial dural arteriovenous fistula in the indirect comparison.

Purpose: To evaluate the feasibility of high-resolution 3D CUBE T1WI for intracranial vessel wall imaging., Methods: High-resolution 3D CUBE T1 weighted intracranial vessel wall images (0.4 mm × 0.4 mm × 0.4 mm) of 50 patients were retrospectively evaluated. A 5-point scale (1 poor, 5 excellent) was used to score the imaging quality for displaying the vessel wall of every intracranial artery segments. The inter-observer and intra-observer reproducibility of identifying plaques, intraplaque hemorrhage/luminal thrombosis, and wall enhancement were calculated., Results: Totally 893 artery segments were evaluated. 3D CUBE T1WI displayed the arteries wall and lumen clearly, with the highest score (4.920 ± 0.837) for the C6-7 segments and the lowest (3.370 ± 1.107) for the C3 segments of the internal carotid artery (ICA). Both intra-observer and inter-observer reproducibility were high for identification of normal walls (κ=0.928, 95% confidence interval [CI] 0.891-0.954; κ=0.911, CI 0.868-0.940), plaque (κ=0.924, CI 0.884-0.954; κ=0.907, CI 0.866-0.943), luminal thrombosis (κ=1.000, CI 1.000-1.000; κ=1.000, CI 1.000-1.000), and wall enhancement (κ=1.000, CI 1.000-1.000; κ=0.914, CI 0.863-0.961)., Conclusions: High-resolution 3D CUBE T1WI displayed intracranial wall and lumen clearly, and detected intracranial artery abnormalities with high reproducibility., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Purpose: Considerable inter-observer variability in the visual assessment of aneurysm recurrences limits its use as an outcome parameter evaluating new coil generations. The purpose of this study was to compare visual assessment of aneurysm recurrences and aneurysm recurrence volumetry with an example dataset of HydroSoft coils (HSC) versus bare platinum coils (BPC)., Methods: For this retrospective study, 3-dimensional time-of-flight magnetic resonance angiography datasets acquired 6 and 12 months after endovascular therapy using BPC only or mainly HSC were analyzed. Aneurysm recurrence volumes were visually rated by two observersas well as quantified by subtraction of the datasets after intensity-based rigid registration., Results: A total of 297 aneurysms were analyzed (BPC: 169, HSC: 128). Recurrences were detected by aneurysm recurrence volumetry in 9 of 128 (7.0 %) treated with HSC and in 24 of 169 (14.2 %) treated with BPC (odds ratio: 2.39, 95 % confidence interval: 1.05-5.48; P = 0.039). Aneurysm recurrence volumetry revealed an excellent correlation between observers (Cronbach's alpha = 0.93). In contrast, no significant difference in aneurysm recurrence was found for visual assessment (3.9 % in HSC cases and 4.7 % in BPC cases). Recurrences were observed in aneurysms smaller than the sample median in 10 of 33 (30.3 %) by aneurysm recurrence volumetry and in 1 of 13 (7.7 %) by visual assessment., Conclusions: Aneurysm recurrences were detected more frequently by aneurysm recurrence volumetry when compared with visual assessment. By using aneurysm recurrence volumetry, differences between treatment groups were detected with higher sensitivity and inter-observer validity probably because of the higher detection rate of recurrences in small aneurysms.

Objectives: To evaluate visualization of the right adrenal vein (RAV) with multidetector CT and non-contrast-enhanced MR imaging in patients with primary aldosteronism., Methods: A total of 125 patients (67 men) scheduled for adrenal venous sampling (AVS) were included. Dynamic 64-detector-row CT and balanced steady-state free precession-based non-contrast-enhanced 3-T MR imaging were performed. RAV visualization based on a four-point score was documented. Both anatomical location and variation on cross-sectional imaging were evaluated, and the findings were compared with catheter venography as the gold standard., Results: The RAV was visualized in 93.2% by CT and 84.8% by MR imaging (p = 0.02). Positive predictive values of RAV visualization were 100% for CT and 95.2% for MR imaging. Imaging score was significantly higher in CT than MR imaging (p < 0.01). The RAV formed a common trunk with an accessory hepatic vein in 16% of patients. The RAV orifice level on cross-sectional imaging was concordant with catheter venography within the range of 1/3 vertebral height in >70% of subjects. Success rate of AVS was 99.2%., Conclusions: Dynamic CT is a reliable way to map the RAV prior to AVS. Non-contrast-enhanced MR imaging is an alternative when there is a risk of complication from contrast media or radiation exposure., Key Points: Dynamic CT and non-contrast-enhanced MR imaging detect the right adrenal vein (RAV). Dynamic CT can visualize the RAV more than non-contrast-enhanced MR imaging. Mapping the RAV helps to achieve successful adrenal venous sampling. Sixteen per cent of RAVs share the common trunk with accessory hepatic veins.

Purpose: To assess whether perfusion and diffusion parameters were different between low-risk tumors and non-low-risk tumors., Materials and Methods: We prospectively enrolled 87 patients with 91 tumors patients (mean, 49.6 years; range, 29-74 years) who underwent definitive surgery. We defined estrogen receptor (ER)-positive tumors with low histologic grade (HG), low Ki67 (<14%), and negative lymph node metastasis as a low-risk breast cancer. We obtained quantitative and semiquantitative perfusion parameters and apparent diffusion coefficient (ADC) for all tumors. We compared perfusion parameters and ADCs between low-risk tumors (n=33; 36%) and the others (n=58; 64%) using Fisher's exact test, Chi-square test, and student t-test. We developed empirical model to predict low-risk tumor using logistic regression analysis and receiver operating characteristics (ROC) analysis., Results: On univariate analysis, wash-in and the initial area under the curve on qualitative analysis (iAUCqualitative) were significantly different according to HG, ER, HER-2, Ki67 and lymphovascular invasion (P<.05 for all variables). ADCdiff was significantly different according to HG, HER-2, and Ki67 status (P=.010, .007, and .013). On multivariate analysis, Ktrans, iAUCqualitative, and ADCdiff were the significant variables for the prediction of low-risk tumors, and the area under the ROC curve (AUC) of combined parameters was 0.78, which was higher than those of the individual parameter. ADCdiff was positively correlated with wash-in (r=0.263) and iAUCqualitative (r=0.245), respectively., Conclusion: The prediction model using Ktrans, wash in, iAUCqualitative, and ADCdiff on DCE-MRI and DWI could be helpful for identifying of low-risk breast cancer and may be used as an imaging biomarker to guide the treatment plan., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Many MRI techniques require prior knowledge of the T1-relaxation time of blood (T1bl). An assumed/fixed value is often used; however, T1bl is sensitive to magnetic field (B0), haematocrit (Hct), and oxygen saturation (Y). We aimed to combine data from previous in vitro measurements into a mathematical model, to estimate T1bl as a function of B0, Hct, and Y. The model was shown to predict T1bl from in vivo studies with a good accuracy (± 87 ms). This model allows for improved estimation of T1bl between 1.5-7.0 T while accounting for variations in Hct and Y, leading to improved accuracy of MRI-derived perfusion measurements., (© The Author(s) 2015.)

Purpose: To evaluate delayed stenosis of the vessels after endovascular thrombectomy using magnetic resonance (MR) angiography., Materials and Methods: Of 82 consecutive patients who underwent successful endovascular treatment for acute intracranial large vessel occlusion between October 2010 and October 2014 at a single institution, 57 patients for whom 3-month radiologic follow-up examinations using MR angiography were available were included in the analysis. MR angiography images were assessed to detect delayed stenosis, which was defined as a decrease in the diameter of treated vessels > 50% compared with MR angiography images obtained 24 hours after endovascular treatment., Results: MR angiography images obtained 3 months after endovascular treatment revealed delayed stenosis of treated vessels in five (8.8%) of 57 patients. All cases of delayed stenosis were asymptomatic and occurred in the middle cerebral artery (MCA). Further serial radiologic follow-up showed gradual improvement of all delayed stenosis over 12 months., Conclusions: Endovascular treatment poses a risk of delayed stenosis of treated vessels, especially in the MCA. MR angiography is a useful modality in long-term follow-up to evaluate delayed stenosis after endovascular treatment., (Copyright © 2015 SIR. Published by Elsevier Inc. All rights reserved.)