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Giant cell arteritis (GCA) is an inflammatory vasculitis affecting large and medium‐sized arteries, leading to complications such as arterial dissection, blindness, and stroke. Rarely, GCA presents with Horner's syndrome due to sympathetic neuron involvement from arterial inflammation. This case report discusses an 82‐year‐old female with hypertension, atrial fibrillation, and arthritis who presented with a 24 h history of right eye ptosis, blurred vision, dizziness, and aching eye pain. She had a mild headache and tenderness over the right temporomandibular joint but no temporal artery tenderness. Examination revealed right eye ptosis and miosis, indicative of Horner's syndrome, with no other neurological deficits. Lab results showed elevated ESR (68 mm/h) and CRP (16 mg/L). MRI with contrast revealed mild to moderate stenosis and enhancement in bilateral MCAs and basilar artery with inflammation in the right distal extracranial ICA, suggesting an inflammatory process. The patient was started on prednisone 40 mg daily. A temporal artery biopsy confirmed GCA with characteristic histopathological findings. Her prednisone dosage was increased to 60 mg/day, and she was started on tocilizumab. This case underscores the need to consider GCA in patients with Horner's syndrome and the importance of vessel wall imaging, as early corticosteroid treatment can prevent complications like vision loss and stroke. [ABSTRACT FROM AUTHOR]

Abstract Vascular dysfunction, characterized by changes in anatomy, hemodynamics, and molecular expressions of vasculatures, is closely linked to the onset and development of diseases, emphasizing the importance of its detection. In clinical practice, medical imaging has been utilized as a significant tool in the assessment of vascular dysfunction, however, traditional imaging techniques still lack sufficient resolution for visualizing the complex microvascular systems. Over the past decade, with the rapid advancement of nanotechnology and the emergence of corresponding detection facilities, engineered nanomaterials offer new alternatives to traditional contrast agents. Compared with conventional small molecule counterparts, nanomaterials possess numerous advantages for vascular imaging, holding the potential to significantly advance related technologies. In this review, the latest developments in nanotechnology-assisted vascular imaging research across different imaging modalities, including contrast-enhanced magnetic resonance (MR) angiography, susceptibility-weighted imaging (SWI), and fluorescence imaging in the second near-infrared window (NIR-II) are summarized. Additionally, the advancements of preclinical and clinical studies related to these nanotechnology-enhanced vascular imaging approaches are outlined, with subsequent discussion on the current challenges and future prospects in both basic research and clinical translation. Graphical Abstract

Arterial spin labeling (ASL) is a noninvasive imaging technique that labels the proton spins in arterial blood and uses them as endogenous tracers. Brain perfusion imaging with ASL is becoming increasingly common in clinical practice, and clinical applications of ASL for intracranial magnetic resonance angiography (MRA) have also been demonstrated. Unlike computed tomography (CT) angiography and cerebral angiography, ASL‐based MRA does not require contrast agents. ASL‐based MRA overcomes most of the disadvantages of time‐of‐flight (TOF) MRA. Several schemes have been developed for ASL‐based MRA; the most common method has been pulsed ASL, but more recently pseudo‐continuous ASL, which provides a higher signal‐to‐noise ratio (SNR), has been used more frequently. New methods that have been developed include direct intracranial labeling methods such as velocity‐selective ASL and acceleration‐selective ASL. MRA using an extremely short echo time (eg, silent MRA) or ultrashort echo‐time (TE) MRA can suppress metal susceptibility artifacts and is ideal for patients with a metallic device implanted in a cerebral vessel. Vessel‐selective 4D ASL MRA can provide digital subtraction angiography (DSA)‐like images. This review highlights the principles, clinical applications, and characteristics of various ASL‐based MRA techniques. Level of Evidence: 5 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Introduction Predicting the shape of the occluded middle cerebral artery (MCA) from the contralateral MCA might help catheterization in endovascular mechanical thrombectomy (EMT). Materials and Methods We analyzed magnetic resonance (MR) angiography in 100 consecutive patients who had MR imaging for diseases other than acute ischemic stroke. To assess the symmetricity of MCA, the shape of M1, length of M1, number of M2, number of early branches (EBs), and distance from the top of the internal carotid artery to EB were investigated. Results The shape of M1 was upward in 42%, horizontal in 47%, and downward in 11%. The M1 shape was the same on both sides in 64%, which exceeded the probability assumed to be left–right independent. The number of M2 trunks and EBs matched left and right in 86 and 55% of patients, respectively; however, these agreement rates were not higher than those with independent left and right sides. No left–right correlation was found between the M1 length and the distance from the internal carotid artery to EB. Conclusion Based on our data, the symmetry of MCA was observed only in the shape of the M1 segment. This finding could be beneficial for EMT targeting MCA embolisms. [ABSTRACT FROM AUTHOR]

Abstract Background Magnetic resonance angiography (MRA) is rapidly being employed as an effective substitute for CTA, particularly in situations of poor kidney function. We aimed to examine the inter-observer and inter-modality reliability of non-contrast MR angiography (NC-MRA) and CTA as a non-invasive tool for assessing the anatomical findings of potential living kidney donors. Results All potential donors were referred from specialized kidney transplantation center and underwent NC-MRA of the renal arteries using a respiratory-triggered magnetization prepared 3D balanced steady-state free precession (b-SSFP) with inversion recovery pulses and fat saturation (Inhance 3D Inflow Inversion Recovery (IFIR)). Two experienced radiologists reviewed NC-MRA images and were asked to evaluate both renal arteries anatomy and their branching pattern, presence of accessory or aberrant renal arteries, and identify any anatomical variant. Lin’s correlation test was performed to test MRA readings by each of the two observers against CTA findings which considered as the gold standard for assessment of renal arteries. Additionally, observers were asked to assess the image quality. The study included 60 potential kidney donors (43 males and 17 females) with mean age ± SD of 31.3 ± 5.6 years. Excellent to very good inter-observer agreement was found between both observers in the assessment of renal arteries by NC-MRA. There was perfect concordance between MRA and CTA findings in detecting early arterial division, caliber, and length of left extra-parenchymal segmental branches. Moderate concordance was found in the assessment of the supplied segments of extra-parenchymal segmental renal arterial branches and substantial concordance between both MRA observers’ findings in the remaining variables of the study. There was excellent agreement between both observers in the assessment of image quality parameters. Conclusions NC-MRA for the renal arteries is an effective alternative for CTA without the risks of radiation or contrast media.

Purpose: To evaluate the multisystem factors contributing to redundant neurovascular orders in the ED. Methods: This was an IRB-approved, retrospective study, performed at a single institution examining a 5-year history of redundant CTA/MRA head and neck (HN) exams performed in the ED for patients with no documented clinical change in mental status/neurological exam necessitating additional imaging. Factors contributing to redundant ordering including provider experience, synchronous order placement, and radiologist recommendations were examined. Additionally, the impact of duplicative imaging in terms of medical cost and ED length of stay was evaluated. Results: 250 patients met inclusion criteria with both CTA/MRA of the HN performed during a single ED encounter (total 500 exams). 190 (76%) redundant exams were not recommended by a radiologist and contributed to an added ED length of stay of 3.6 h on average. Provider experience was not a significant contributing factor. 60 (24%) of redundant exams were recommended by a radiologist and were most frequently CTAs needed to clarify an area of artifact/high-grade stenosis/occlusion on a primary MRA exam. Conclusion: Evaluation of contributing factors to redundant CTA/MRA HN exams ordering has highlighted multiple associated factors including provider experience, recommendations by radiologists for clarification of MRA findings, as well as systems processes related to synchronous CTA/MRA order placement. [ABSTRACT FROM AUTHOR]

Background and Aims: Susceptibility‐weighted imaging (SWI) can help in the diagnosis of thrombus within the vessel in acute ischemic stroke, known as susceptibility vessel sign (SVS), and detection of SVS within the vessel can predict treatment modality and outcome. In this study, the purpose is to correlate the SVS on SWI with different parameters of stroke. Methods: This prospective cross‐sectional study enrolled consecutive stroke patients with vessel occlusion on magnetic resonance angiography (MRA) over 1 year. The relationship between SVS on SWI with risk factors, territory involved, and length of thrombus was correlated with the National Institutes of Health Stroke Scale (NIHSS). Results: A total of 105 patients were enrolled in this study. Sixty‐two percent (66 out of 105) of patients showed SVS on SWI with MRA‐positive occlusion. A positive correlation was observed between SVS on SWI and the risk factor (p = 0.003, chi‐square test), with 86% of patients with heart disease and 47% with hypertension exhibiting SVS. Additionally, a positive correlation was observed between SVS on SWI and territorial occlusion (p = 0.000, chi‐square test). A moderate positive correlation was observed between the NIHSS and thrombus length (p = 0.002, Pearson's correlation coefficient), with a Pearson's coefficient of 0.367. Conclusions: SWI can be useful in identifying the location of the thrombus, and NIHSS can determine the thrombus length in acute stroke. A higher incidence of SVS can be associated with risk factors, and it also depends upon the site of occlusion of the vessel. Key points: Sixty‐two percent of patients showed susceptibility vessel sign (SVS) on susceptibility‐weighted imaging (SWI) with magnetic resonance angiography (MRA)‐positive occlusion, indicating the potential of SWI in assessing stroke severity.Positive correlations were observed between SVS and risk factors (heart disease, hypertension), territorial occlusion, and a moderate correlation between the NIH Stroke Scale (NIHSS) score and thrombus length.SWI is highlighted as a valuable tool due to its superior sensitivity in detecting blood products and vascular anomalies, emphasizing its role in identifying thrombus location and predicting treatment outcomes in acute ischemic stroke. [ABSTRACT FROM AUTHOR]

Background: Magnetic resonance angiography (MRA) is rapidly being employed as an effective substitute for CTA, particularly in situations of poor kidney function. We aimed to examine the inter-observer and inter-modality reliability of non-contrast MR angiography (NC-MRA) and CTA as a non-invasive tool for assessing the anatomical findings of potential living kidney donors. Results: All potential donors were referred from specialized kidney transplantation center and underwent NC-MRA of the renal arteries using a respiratory-triggered magnetization prepared 3D balanced steady-state free precession (b-SSFP) with inversion recovery pulses and fat saturation (Inhance 3D Inflow Inversion Recovery (IFIR)). Two experienced radiologists reviewed NC-MRA images and were asked to evaluate both renal arteries anatomy and their branching pattern, presence of accessory or aberrant renal arteries, and identify any anatomical variant. Lin's correlation test was performed to test MRA readings by each of the two observers against CTA findings which considered as the gold standard for assessment of renal arteries. Additionally, observers were asked to assess the image quality. The study included 60 potential kidney donors (43 males and 17 females) with mean age ± SD of 31.3 ± 5.6 years. Excellent to very good inter-observer agreement was found between both observers in the assessment of renal arteries by NC-MRA. There was perfect concordance between MRA and CTA findings in detecting early arterial division, caliber, and length of left extra-parenchymal segmental branches. Moderate concordance was found in the assessment of the supplied segments of extra-parenchymal segmental renal arterial branches and substantial concordance between both MRA observers' findings in the remaining variables of the study. There was excellent agreement between both observers in the assessment of image quality parameters. Conclusions: NC-MRA for the renal arteries is an effective alternative for CTA without the risks of radiation or contrast media. [ABSTRACT FROM AUTHOR]

Purpose: 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. Methods: 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. Results: 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. Conclusion: 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. [ABSTRACT FROM AUTHOR]

Two major drawbacks of 4D-MR angiography based on superselective pseudo-continuous arterial spin labeling combined with CENTRA-keyhole and view-sharing (4D-S-PACK) are the low temporal resolution and long scanning time. We investigated the feasibility of increasing the temporal resolution and accelerating the scanning time on 4D-S-PACK by using CS-SENSE and PhyZiodynamics, a novel image-processing program that interpolates images between phases to generate new phases and reduces image noise. Seven healthy volunteers were scanned with a 3.0 T MR scanner to visualize the internal carotid artery (ICA) system. PhyZiodynamics is a novel image-processing that interpolates images between phases to generate new phases and reduces image noise, and by increasing temporal resolution using PhyZiodynamics, inflow dynamic data (reference) were acquired by changing the labeling durations (100–2000 msec, 31 phases) in 4D-S-PACK. From this set of data, we selected seven time intervals to calculate interpolated time points with up to 61 intervals using ×10 for the generation of interpolated phases with PhyZiodynamics. In the denoising process of PhyZiodynamics, we processed the none, low, medium, high noise reduction dataset images. The time intensity curve (TIC), the contrast-to-noise ratio (CNR) were evaluated. In accelerating with CS-SENSE for 4D-S-PACK, 4D-S-PACK were scanned different SENSE or CS-SENSE acceleration factors: SENSE3, CS3–6. Signal intensity (SI), CNR, were evaluated for accelerating the 4D-S-PACK. With regard to arterial vascular visualization, we evaluated the middle cerebral artery (MCA: M1–4 segments). In increasing temporal resolution, the TIC showed a similar trend between the reference dataset and the interpolated dataset. As the noise reduction weight increased, the CNR of the interpolated dataset were increased compared to that of the reference dataset. In accelerating 4D-S-PACK, the SI values of the SENSE3 dataset and CS dataset with CS3–6 were no significant differences. The image noise increased with the increase of acceleration factor, and the CNR decreased with the increase of acceleration factor. Significant differences in CNR were observed between acceleration factor of SENSE3 and CS6 for the M1–4 (P < 0.05). Visualization of small arteries (M4) became less reliable in CS5 or CS6 images. Significant differences were found for the scores of M2, M3 and M4 segments between SENSE3 and CS6. With PhyZiodynamics and CS-SENSE in 4D-S-PACK, we were able to shorten the scan time while improving the temporal resolution. • PhyZiodynamics improves temporal resolution maintaining TIC and high CNR. • By using CS-SENSES, scan time of 4D-S-PACK can be reduced by 1 min. • 4D-S-PACK with PhyZiodynamics and CS-SENSE may rival the 4D-DSA of diagnostic power. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to improve the qualitative and quantitative image quality of the time-resolved angiography with interleaved stochastic trajectories technique (4D-TWIST-MRA) using deep neural network (DNN)-based MR image reconstruction software. Materials and Methods: A total of 520 consecutive patients underwent 4D-TWIST-MRA for ischemic stroke or intracranial vessel stenosis evaluation. Four-dimensional DNN-reconstructed MRA (4D-DNR) was generated using commercially available software (SwiftMR v.3.0.0.0, AIRS Medical, Seoul, Republic of Korea). Among those evaluated, 397 (76.3%) patients received concurrent time-of-flight MRA (TOF-MRA) to compare the signal-to-noise ratio (SNR), image quality, noise, sharpness, vascular conspicuity, and degree of venous contamination with a 5-point Likert scale. Two radiologists independently evaluated the detection rate of intracranial aneurysm in TOF-MRA, 4D-TWIST-MRA, and 4D-DNR in separate sessions. The other 123 (23.7%) patients received 4D-TWIST-MRA due to a suspicion of acute ischemic stroke. The confidence level and decision time for large vessel occlusion were evaluated in these patients. Results: In qualitative analysis, 4D-DNR demonstrated better overall image quality, sharpness, vascular conspicuity, and noise reduction compared to 4D-TWIST-MRA. Moreover, 4D-DNR exhibited a higher SNR than 4D-TWIST-MRA. The venous contamination and aneurysm detection rates were not significantly different between the two MRA images. When compared to TOF-MRA, 4D-CE-MRA underestimated the aneurysm size (2.66 ± 0.51 vs. 1.75 ± 0.62, p = 0.029); however, 4D-DNR showed no significant difference in size compared to TOF-MRA (2.66 ± 0.51 vs. 2.10 ± 0.41, p = 0.327). In the diagnosis of large vessel occlusion, 4D-DNR showed a better confidence level and shorter decision time than 4D-TWIST-MRA. Conclusion: DNN reconstruction may improve the qualitative and quantitative image quality of 4D-TWIST-MRA, and also enhance diagnostic performance for intracranial aneurysm and large vessel occlusion. [ABSTRACT FROM AUTHOR]

BackgroundCOVID-19 infections have been implicated in cerebral ischemia, but their relationship to cervical arterial dissections remains poorly characterized. Descriptions of cervical arterial dissections in patients with COVID-19 infections with details regarding their presenting symptomatology, imaging findings, and responses to treatment with antithrombotic therapy may be helpful to clinicians.Methods and observationsWe present six adult cases of cervical arterial dissections in the setting of recent COVID-19 infections from 2021 to 2022 at our institution. Four cases presented with dissections involving the internal carotid artery, while two cases had dissections of bilateral vertebral arteries. In one patient, we found imaging evidence for a possible inflammatory process. All patients were treated with either antiplatelet agents or direct oral anticoagulants.Conclusions and relevanceCOVID-19 infections may predispose patients to spontaneous cervical arterial dissections. Such patients can have variable neurologic presentations, though headaches and neck pain were common complaints. Most patients responded well to antithrombotic therapy, with improvement in symptoms and radiologic findings at follow-up. Clinicians should maintain a high degree of suspicion for cervical arterial dissections in patients who present acutely with severe headache/neck pain and/or new neurologic deficits in the setting of COVID-19 infections.

The ferumoxytol-enhanced 4D MR angiography with MUSIC (Multiphase Steady State Imaging with Contrast) technique provides a single data set that captures dynamic cardiovascular anatomy and ventricular function at the same time. Homogeneous opacification of all cardiovascular structures within the imaging volume allows full sequential segmental approach to the congenital heart diseases without any blind spots. The complex systemic and pulmonary venous anatomy is particularly well captured in the MUSIC. Cinematographic display of multiplanar sectional and 3D volume images is helpful in the morphological identification of the cardiac chambers, the assessment of the dynamic nature of the ventricular outflow tracts, and the assessment of the coronary arterial origins and courses.

Abstract Knowledge about anatomical details seems to facilitate the procedure and planning of prostatic artery embolization (PAE) in patients with symptomatic benign prostatic hyperplasia (BPS). The aim of our study was the pre-interventional visualization of the prostatic artery (PA) with MRA and the correlation of iliac elongation and bifurcation angles with technical success of PAE and technical parameters. MRA data of patients with PAE were analysed retrospectively regarding PA visibility, PA type, vessel elongation, and defined angles were correlated with intervention time, fluoroscopy time, dose area product (DAP), cumulative air kerma (CAK), contrast media (CM) dose and technical success of embolization. T-test, ANOVA, Pearson correlation, and Kruskal–Wallis test was applied for statistical analysis. Between April 2018 and March 2021, a total of 78 patients were included. MRA identified the PA origin in 126 of 147 cases (accuracy 86%). Vessel elongation affected time for catheterization of right PA (p = 0.02), fluoroscopy time (p = 0.05), and CM dose (p = 0.02) significantly. Moderate correlation was observed for iliac bifurcation angles with DAP (r = 0.30 left; r = 0.34 right; p = 0.01) and CAK (r = 0.32 left; r = 0.36 right; p = 0.01) on both sides. Comparing the first half and second half of patients, median intervention time (125 vs. 105 min.) and number of iliac CBCT could be reduced (p

A modern vascular service cannot function without high quality, timely and relevant diagnostic imaging. In this age of evidence-based medicine, radiological findings and their expert interpretation are fundamental in aiding decisions with regard to patient management and surgical intervention. In this chapter we present the principles, clinical indications, advantages and limitations of the different imaging modalities used to assess vascular patients including duplex ultrasound (DUS), computed tomography (CT), magnetic resonance imaging (MR) and digital subtraction angiography (DSA). [ABSTRACT FROM AUTHOR]

Background: Lenticulostriate artery (LSA) obstruction is a potential cause of subcortical infarcts. However, MRI LSA evaluation at 3T is challenging. Purpose: To investigate middle cerebral artery (MCA) plaque characteristics and LSA morphology associated with subcortical infarctions in LSA territories using 7‐T vessel wall MRI (VW‐MRI) and time‐of‐flight MR angiography (TOF‐MRA). Study Type: Prospective. Population: Sixty patients with 80 MCA atherosclerotic plaques (37 culprit and 43 non‐culprit). Field Strength/Sequence: 7‐T with 3D TOF‐MRA and T1‐weighted 3D sampling perfection with application‐optimized contrast using different flip angle evolutions (SPACE) sequences. Assessment: Plaque distribution (superior, inferior, ventral, or dorsal walls), LSA origin involvement, LSA morphology (numbers of stems, branches, and length), and plaque characteristics (normalized wall index, maximal wall thickness, plaque length, remodeling index, intraplaque hemorrhage, and plaque surface morphology (regular or irregular)) were assessed. Statistical Tests: Least absolute shrinkage and selection operator regression, generalized estimating equations regression, receiver operating characteristic curve, independent t‐test, Mann–Whitney U test, Chi‐square test, Fisher's exact test, and intra‐class coefficient. A P value <0.05 was considered statistically significant. Results: Plaque irregular surface, superior wall plaque, longer plaque length, LSA origin involvement, fewer LSA stems, and shorter total and average lengths of LSAs were significantly associated with culprit plaques. Multivariable logistic analysis confirmed that LSA origin involvement (OR, 28.51; 95% CI, 6.34–181.02) and plaque irregular surface (OR, 8.32; 95% CI, 1.41–64.73) were independent predictors in differentiating culprit from non‐culprit plaques. A combination of LSA origin involvement and plaque irregular surface (area under curve = 0.92; [95% CI, 0.86–0.98]) showed good performance in identifying culprit plaques, with sensitivity and specificity of 86.5% and 86.0%, respectively. Data Conclusion: 7‐T VW‐MRI and TOF‐MRA can demonstrate plaque involvement with LSA origins. MCA plaque characteristics derived from 7‐T VW‐MRI showed good diagnostic accuracy in determining the occurrence of subcortical infarctions. Evidence Level: 2 Technical Efficacy: Stage 3 [ABSTRACT FROM AUTHOR]

Abstract Background and Aims Susceptibility‐weighted imaging (SWI) can help in the diagnosis of thrombus within the vessel in acute ischemic stroke, known as susceptibility vessel sign (SVS), and detection of SVS within the vessel can predict treatment modality and outcome. In this study, the purpose is to correlate the SVS on SWI with different parameters of stroke. Methods This prospective cross‐sectional study enrolled consecutive stroke patients with vessel occlusion on magnetic resonance angiography (MRA) over 1 year. The relationship between SVS on SWI with risk factors, territory involved, and length of thrombus was correlated with the National Institutes of Health Stroke Scale (NIHSS). Results A total of 105 patients were enrolled in this study. Sixty‐two percent (66 out of 105) of patients showed SVS on SWI with MRA‐positive occlusion. A positive correlation was observed between SVS on SWI and the risk factor (p = 0.003, chi‐square test), with 86% of patients with heart disease and 47% with hypertension exhibiting SVS. Additionally, a positive correlation was observed between SVS on SWI and territorial occlusion (p = 0.000, chi‐square test). A moderate positive correlation was observed between the NIHSS and thrombus length (p = 0.002, Pearson's correlation coefficient), with a Pearson's coefficient of 0.367. Conclusions SWI can be useful in identifying the location of the thrombus, and NIHSS can determine the thrombus length in acute stroke. A higher incidence of SVS can be associated with risk factors, and it also depends upon the site of occlusion of the vessel.

Vein of Galen aneurysmal malformation (VGAM) is a rare vascular anomaly originating during embryonic development, specifically between the 6th and 11th weeks of gestation. This malformation results from abnormal arteriovenous connections between primitive choroidal arteries and the median prosencephalic vein (MPV) of Markowski. Typically, the MPV regresses by the 11th week, but in VGAM, this regression is hindered, leading to persistent abnormal flow and the formation of arteriovenous shunts. We present a case of successful prenatal detection, as well as a comprehensive literature review that summarizes current knowledge, emphasizes the importance of prenatal detection, detailed imaging techniques, understanding clinical presentations, and outlines treatment options. Prenatal detection, crucial for early intervention, has become feasible through ultrasonography and MRI. Fetal MRI has emerged as the gold standard, offering detailed insights into arterial feeders, nidus presence, fistula position, venous drainage, and potential complications. The clinical presentation of VGAM varies with age, and neonates diagnosed in utero may exhibit signs of high-output cardiac failure. Early detection is critical for timely intervention, as untreated VGAMs often result in high mortality rates. Prognosis depends on the severity of heart failure, the number of arteriovenous shunts, and the presence of accompanying fetal abnormalities. Various imaging modalities, including CT angiography and digital subtraction angiography (DSA), aid in the assessment and treatment of VGAM. DSA remains the gold standard for evaluating angioarchitecture and guiding endovascular interventions. The optimal treatment for VGAM is transarterial embolization, offering significant improvements in prognosis. Surgical interventions are limited due to high morbidity and mortality. Management decisions should consider the balance between minimizing neurological damage and achieving maximum embolization effectiveness.

Vascular imaging can be challenging because of the wide variability of contrast dynamics in different vascular territories and potential safety concerns in patients with renal insufficiency or allergies. Off-label diagnostic use of ferumoxytol, a superparamagnetic iron nanoparticle approved for therapy, is a promising alternative to gadolinium-based contrast agents for MR angiography (MRA). Ferumoxytol has exhibited a reassuring safety profile when used within the dose range recommended for diagnostic imaging. Because of its prolonged and stable intravascular residence, ferumoxytol can be used in its steady-state distribution for a wide variety of imaging indications, including some where conventional MRA is unreliable. In this article, authors discuss some of the major vascular applications of ferumoxytol and highlight how it may be used to provide highly diagnostic images and improve the quality, workflow, and reliability of vascular imaging. Keywords: MR Angiography, MRI Contrast Agent, Cardiac, Vascular © RSNA, 2022.

Jianmin Li,1,2,&ast; Wenyi Zhang,1,2,&ast; Shuang Liu,1,2,&ast; Fan Yang,2 Yupeng Zhou,2 Lin Cao,1,2 Yiming Li,1,2 Yunfei Guo,1,2 Xiang Qi,1,2 Guoping Xu,1 Jing Peng,1 Yang Zhao1,2 1Department of Radiology, The Second Hospital of Tianjin Medical University, Tianjin, People’s Republic of China; 2Tianjin Institute of Urology, The Second Hospital of Tianjin Medical University, Tianjin, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Yang Zhao; Jing Peng, Department of Radiology, The Second Hospital of Tianjin Medical University, Tianjin, 300211, People’s Republic of China, Email yang.zhao@tmu.edu.cn; jing.peng@tmu.edu.cnPurpose: BSA-biomineralized Gd nanoparticles (Gd@BSA NPs) have been recognized as promising nanoscale MR contrast agents. The aim of this study was to carry out a preclinical evaluation of these NPs in a middle-sized animal model (rabbits).Methods: New Zealand white rabbits were treated intravenously with Gd@BSA NPs (0.02 mmol Gd/kg) via a clinically-used high-pressure injector, with commercial Gd-diethylene triamine pentaacetate (Gd-DTPA)-injected group as control. Then MR angiography was performed according to the standard clinical protocol with a 3.0-T MR scanner. The SNR and CNR of the main arteries and branches were monitored. Pharmacokinetics and bioclearance were continuously evaluated in blood, urine, and feces. Gd deposition in vital organs was measured by ICP‒MS. Weight monitoring, HE staining, and blood biochemical analysis were also performed to comprehensively estimate systemic toxicity.Results: The ultrasmall Gd@BSA NPs (< 6 nm) exhibited high stability and T1 relaxivity. Compared to Gd-DTPA, Gd@BSA NPs demonstrated superior vascular system imaging performance at ultralow doses, especially of the cardiac artery and other main branches, and exhibited a significantly higher SNR and CNR. Notably, the Gd@BSA NPs showed a shorter half-life in blood, less retention in organs, and improved biocompatibility.Conclusion: The preclinical evaluations here demonstrated that Gd@BSA NPs are promising and advantageous MR CA candidates that can be used at a low dose with excellent MR imaging performance, thus suggesting its further clinical trials and applications.Keywords: preclinical evaluation, ultralow dose, high-pressure injector, MR angiography

PurposeAlthough radiation therapy (RT) is a common treatment for pediatric brain tumors, it is associated with detrimental long-term effects such as impaired cognition, vascular injury, and increased stroke risk. This study aimed to develop metrics that describe vascular injury and relate them to the presence of cerebral microbleeds (CMBs) and cognitive performance scores.MethodsTwenty-five young adult survivors of pediatric brain tumors treated with either whole-brain (n = 12), whole-ventricular (n = 7), or no RT (n = 6) underwent 7T MRI and neurocognitive testing. Simultaneously acquired MR angiography and susceptibility-weighted images were used to segment CMBs and vessels and quantify their radii and volume.ResultsPatients treated with whole-brain RT had significantly lower arterial volumes (p = 0.003) and a higher proportion of smaller vessels (p = 0.003) compared to the whole-ventricular RT and non-irradiated control patients. Normalized arterial volume decreased with increasing CMB count (R = - 0.66, p = 0.003), and decreasing trends were observed with time since RT and at longitudinal follow-up. Global cognition and verbal memory significantly decreased with smaller normalized arterial volume (p ≤ 0.05).ConclusionsArterial volume is reduced with increasing CMB presence and is influenced by the total brain volume exposed to radiation. This work highlights the potential use of vascular-derived metrics as non-invasive markers of treatment-induced injury and cognitive impairment in pediatric brain tumor patients.

ABSTRACT: Background: Three-dimensional (3D) contrast-enhanced magnetic resonance angiography (CEMRA) is routinely used for vascular evaluation. With existing techniques for CEMRA, diagnostic image quality is only obtained during the first pass of the contrast agent or shortly thereafter, whereas angiographic quality tends to be poor when imaging is delayed to the equilibrium phase. We hypothesized that prolonged blood pool contrast enhancement could be obtained by imaging with a balanced T1 relaxation-enhanced steady-state (bT1RESS) pulse sequence, which combines 3D balanced steady-state free precession (bSSFP) with a saturation recovery magnetization preparation to impart T1 weighting and suppress background tissues. An electrocardiographic-gated, two-dimensional-accelerated version with isotropic 1.1-mm spatial resolution was evaluated for breath-hold equilibrium phase CEMRA of the thoracic aorta and heart. Methods: The study was approved by the institutional review board. Twenty-one subjects were imaged using unenhanced 3D bSSFP, time-resolved CEMRA, first-pass gated CEMRA, followed by early and late equilibrium phase gated CEMRA and bT1RESS. Nine additional subjects were imaged using equilibrium phase 3D bSSFP and bT1RESS. Images were evaluated for image quality, aortic root sharpness, and visualization of the coronary artery origins, as well as using standard quantitative measures. Results: Equilibrium phase bT1RESS provided better image quality, aortic root sharpness, and coronary artery origin visualization than gated CEMRA (P

Background: We aimed to evaluate the feasibility of a non-contrast time-of-flight magnetic resonance angiography (TOF-MRA) protocol for the pre-procedural access route assessment of transcatheter aortic valve implantation (TAVI) in comparison with contrast-enhanced cardiac dual-source computed tomography angiography (CTA). Methods and Results: In total, 51 consecutive patients (mean age: 82.69 ± 5.69 years) who had undergone a pre-TAVI cardiac CTA received TOF-MRA for a pre-procedural access route assessment. The MRA image quality was rated as very good (median of 5 [IQR 4–5] on a five-point Likert scale), with only four examinations rated as non-diagnostic. The TOF-MRA systematically underestimated the minimal effective vessel diameter in comparison with CTA (for the effective vessel diameter in mm, the right common iliac artery (CIA)/external iliac artery (EIA)/common femoral artery (CFA) MRA vs. CTA was 8.04 ± 1.46 vs. 8.37 ± 1.54 (p < 0.0001) and the left CIA/EIA/CFA MRA vs. CTA was 8.07 ± 1.32 vs. 8.28 ± 1.34 (p < 0.0001)). The absolute difference between the MRA and CTA was small (for the Bland–Altman analyses in mm, the right CIA/EIA/CFA was −0.36 ± 0.77 and the left CIA/EIA/CFA was −0.25 ± 0.61). The overall correlation between the MRA and CTA measurements was very good (with a Pearson correlation coefficient of 0.87 (p < 0.0001) for the right CIA/EIA/CFA and a Pearson correlation coefficient of 0.9 (p < 0.0001) for the left CIA/EIA/CFA). The feasibility agreement between the MRA and CTA for transfemoral access was good (the right CIA/EIA/CFA agreement was 97.9% and the left CIA/EIA/CFA agreement was 95.7%, Kohen's kappa: 0.477 (p = 0.001)). Conclusions: The TOF-MRA protocol was feasible for the assessment of the access route in an all-comer pre-TAVI population. This protocol might be a reliable technique for patients at an increased risk of contrast-induced nephropathy. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate clinical and imaging characteristics of pediatric brain aneurysms. Materials and Methods: A retrospective review of 1458 MR angiograms of pediatric patients (≤18 years old) obtained between 2006 and 2021 was performed. A non-infundibular arterial luminal outpouching larger than 1mm in size was identified as an "Intracranial aneurysm." Patient demographics, clinical presentations, and predisposing risk factors, including family history and underlying medical conditions, were reviewed. MRA images were analyzed for aneurysm location, number, maximum diameter, and interval changes on follow-up. Results: Forty-nine (3.3%) patients (30 females, 19 males) with 64 intracranial aneurysms were identified with an average age of 13.71 ± 3.67 years. Eleven (22.4%) patients had multiple aneurysms. An underlying systemic illness was observed in 81.6% (40/49) cases, with sickle cell disease as the most frequent (25/49, 51%) diagnosis. A first-degree family history of intracranial aneurysms was recognized in 36/1458 (2.5%) patients. However, no intracranial aneurysm was found in this group. While 02/49 (4%) patients presented with acute SAH, headache was the most common (16/49, 32.7%) symptom at presentation in unruptured cases. The majority (47/64, 73.4%) of the aneurysms were located in the anterior circulation, with the ICA ophthalmic segment being most frequently (24/47, 51%) involved. Most (54/64, 84.4%) aneurysms were smaller than 4mm in size at the time of diagnosis. At least one follow-up MRA was obtained in 72.3% (34/47) of the unruptured aneurysms cohort. There was no change in the aneurysm size and morphology in 31/34 (91.2 %) patients over an average imaging follow-up of 39.6 months. Three (6%) patients demonstrated an interval increase in the aneurysm size. SAH patients (n=2) and two unruptured aneurysm patients with an interval increase in size were successfully treated with endovascular techniques. Conclusion: Female predominance with a higher frequency of small and unruptured intracranial aneurysms was recognized in our cohort. A higher incidence of an underlying systemic illness, especially sickle cell disease, was also noted. Most intracranial aneurysms in children appear to remain stable. However, there seems to be the risk of an aneurysm size increase which warrants regular clinical and imaging follow-up. [ABSTRACT FROM AUTHOR]

The temporopolar artery (TPA) originates directly from the sphenoidal segment of the middle cerebral artery (MCA). Its originating from the M1 segment of the MCA as a branch of the anterior temporal artery is not uncommon. However, internal carotid artery origination is a very rare variation of the TPA. Here, we report a very rare case of the variant origin of the TPA and the presence of saccular aneurysm at this origin. [ABSTRACT FROM AUTHOR]

This article discusses the role of color Doppler ultrasound and magnetic resonance angiography (MRA) in the evaluation of extracranial carotid and vertebral arteries in patients with stroke. The study involved 120 patients who were examined using both Doppler ultrasound and MRA. The findings of both modalities were compared, and the percentage of stenosis was given based on the North American Symptomatic Carotid Endarterectomy Trial (NASCET) classification. The study found that the age group most affected by stroke was 51-60 years, and the gender distribution was skewed towards males. The majority of patients had soft tissue plaque, and right-side involvement was most common. The study concludes that the combination of Doppler ultrasound and MRA provides complementary information and can be helpful in characterizing atherosclerotic plaque and detecting carotid stenosis. [ABSTRACT FROM AUTHOR]

Purpose: To develop an accelerated 3D intracranial time‐of‐flight (TOF) magnetic resonance angiography (MRA) sequence with wave‐encoding (referred to as 3D wave‐TOF) and to evaluate two variants: wave–controlled aliasing in parallel imaging (CAIPI) and compressed‐sensing wave (CS‐wave). Methods: A wave‐TOF sequence was implemented on a 3 T clinical scanner. Wave‐encoded and Cartesian k‐space datasets from six healthy volunteers were retrospectively and prospectively undersampled with 2D‐CAIPI sampling and variable‐density Poisson disk sampling. 2D‐CAIPI, wave‐CAIPI, standard CS, and CS‐wave schemes were compared at various acceleration factors. Flow‐related artifacts in wave‐TOF were investigated, and a set of practicable wave parameters was developed. Quantitative analysis of wave‐TOF and traditional Cartesian TOF MRA was performed by comparing the contrast‐to‐background ratio between the vessel and background tissue in source images, and the structural similarity index measure (SSIM) between the maximum intensity projection images from accelerated acquisitions and their respective fully sampled references. Results: Flow‐related artifacts caused by the wave‐encoding gradients in wave‐TOF were eliminated by properly chosen parameters. Images from wave‐CAIPI and CS‐wave acquisitions had a higher SNR and better‐preserved contrast than traditional parallel imaging (PI) and CS methods. Maximum intensity projection images from wave‐CAIPI and CS‐wave acquisitions had a cleaner background, with vessels that were better depicted. Quantitative analyses indicated that wave‐CAIPI had the highest contrast‐to‐background ratio, SSIM, and vessel‐masked SSIM among the sampling schemes studied, followed by the CS‐wave acquisition. Conclusion: 3D wave‐TOF improves the capability of accelerated MRA and provides better image quality at higher acceleration factors compared to traditional PI‐ or CS‐accelerated TOF, suggesting the potential use of wave‐TOF in cerebrovascular disease. [ABSTRACT FROM AUTHOR]

Copyright of Clinical Neuroscience / Ideggyógyászati Szemle is the property of LifeTime Media Kft. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Unruptured intracranial aneurysms are often discovered incidentally on noninvasive imaging. As use of noninvasive imaging has increased, our understanding of the presumed prevalence of intracranial aneurysms in adults has increased. Incidentally found aneurysms are often asymptomatic; however, they can rarely rupture and cause life-threatening illness. Elective treatment of intracranial aneurysms carries risks which need to be considered along with patient-specific factors (e.g., anatomy, medical comorbidities, personal preferences). In this article, we review the natural history, risk factors for cerebral aneurysm formation and rupture, evidence for medical management, and the safety profile and efficacy of available endovascular treatment options. [ABSTRACT FROM AUTHOR]

Copyright of Archives of the Turkish Society of Cardiology / Türk Kardiyoloji Derneği Arşivi is the property of KARE Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Ferumoxytol, an intravenous iron supplement, is commonly used to treat anemia in pregnancy. Ferumoxytol‐enhanced magnetic resonance angiography (Fe‐MRA) is a viable off‐label alternative to gadolinium‐enhanced MRA for assessment of pulmonary embolism (PE) in pregnancy. Purpose: To describe our clinical experience with Fe‐MRA in pregnant women with suspected PE. Study type: Retrospective, observational, cohort. Population: A total of 98 Fe‐MRA exams (consecutive sample) performed in 94 pregnant women. Field Strength/Sequence: A 1.5 T and 3.0 T, 3D T1‐weighted MRA. Assessment: After IRB approval including a waiver of informed consent, electronic health records were reviewed retrospectively for all Fe‐MRA exams performed at our institution in pregnant between January, 2017 and March, 2022. The Fe‐MRA protocol included 3D‐MRA for assessment of pulmonary arteries, and T1‐weighted imaging for ancillary findings. Fe‐MRA exam duration was measured from image time stamps. Fe‐MRA exams were reviewed by three cardiovascular imagers using a 4‐point Likert scale for image quality and confidence for PE diagnosis (score 4 = best, 1 = worst), and tabulation of ancillary findings. Statistical tests: Continuous data are presented as mean ± standard deviation. The overall image quality and confidence score is given as the mean of three readers. Results: The 98 Fe‐MRA exams were performed in 94 pregnant women (age 30 ± 6, range 19–48 years, gestational week 23 ± 10, range 3–38 weeks), with four undergoing two Fe‐MRA exams during their pregnancy. Median Fe‐MRA exam durration was 8 minutes (interquantile range 6 minutes). Overall image quality score was 3.3 ± 0.9. Confidence score for diagnosing PE was 3.5 ± 0.8. One subject was positive for PE (1/94, 1%); 42 of the 94 (45%) subjects Fe‐MRA had ancillary findings including hydronephrosis or pneumonia. Conclusion: Ferumoxytol enhanced MRA is a radiation‐ and gadolinium‐free alternative for diagnosis of PE during pregancy. Evidence Level: 4 Technical Efficacy: Stage 5 [ABSTRACT FROM AUTHOR]

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

The ferumoxytol-enhanced 4D MR angiography with MUSIC (Multiphase Steady State Imaging with Contrast) technique provides a single data set that captures dynamic cardiovascular anatomy and ventricular function at the same time. Homogeneous opacification of all cardiovascular structures within the imaging volume allows full sequential segmental approach to the congenital heart diseases without any blind spots. The complex systemic and pulmonary venous anatomy is particularly well captured in the MUSIC. Cinematographic display of multiplanar sectional and 3D volume images is helpful in the morphological identification of the cardiac chambers, the assessment of the dynamic nature of the ventricular outflow tracts, and the assessment of the coronary arterial origins and courses.

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

Advances in artificial intelligence (AI), especially deep learning (DL), have facilitated magnetic resonance imaging (MRI) data analysis, enabling AI-assisted medical image diagnoses and prognoses. However, most of the DL models are considered as "black boxes". There is an unmet need to demystify DL models so domain experts can trust these high-performance DL models. This has resulted in a sub-domain of AI research called explainable artificial intelligence (XAI). In the last decade, many experts have dedicated their efforts to developing novel XAI methods that are competent at visualizing and explaining the logic behind data-driven DL models. However, XAI techniques are still in their infancy for medical MRI image analysis. This study aims to outline the XAI applications that are able to interpret DL models for MRI data analysis. We first introduce several common MRI data modalities. Then, a brief history of DL models is discussed. Next, we highlight XAI frameworks and elaborate on the principles of multiple popular XAI methods. Moreover, studies on XAI applications in MRI image analysis are reviewed across the tissues/organs of the human body. A quantitative analysis is conducted to reveal the insights of MRI researchers on these XAI techniques. Finally, evaluations of XAI methods are discussed. This survey presents recent advances in the XAI domain for explaining the DL models that have been utilized in MRI applications. [ABSTRACT FROM AUTHOR]

Background: Pulmonary hypertension (PH) contributes to restricted flow through the pulmonary circulation characterized by elevated mean pulmonary artery pressure acquired from invasive right heart catheterization (RHC). MRI may provide a noninvasive alternative for diagnosis and characterization of PH. Purpose: To characterize PH via quantification of regional pulmonary transit times (rPTT). Study Type: Retrospective. Population: A total of 43 patients (58% female); 24 controls (33% female). RHC‐confirmed patients classified as World Health Organization (WHO) subgroups 1–4. Field Strength/Sequence: A 1.5 T/time‐resolved contrast‐enhanced MR Angiography (CE‐MRA). Assessment: CE‐MRA data volumes were combined into a 4D matrix (3D resolution + time). Contrast agent arrival time was defined as the peak in the signal‐intensity curve generated for each voxel. Average arrival times within a vessel region of interest (ROI) were normalized to the main pulmonary artery ROI (t0) for eight regions to define rPTT for all subjects. Subgroup analysis included grouping the four arterial and four venous regions. Intraclass correlation analysis completed for reproducibility. Statistical Tests: Analysis of covariance with age as covariate. A priori Student's t‐tests or Wilcoxon rank‐sum test; α = 0.05. Results compared to controls unless noted. Significant without listing P value. ICC ran as two‐way absolute agreement model with two observers. Results: PH patients demonstrated elevated rPTT in all vascular regions; average rPTT increase in arterial and venous branches was 0.85 ± 0.15 seconds (47.7%) and 1.0 ± 0.18 seconds (16.9%), respectively. Arterial rPTT was increased for all WHO subgroups; venous regions were elevated for subgroups 2 and 4 (group 1, P = 0.86; group 3, P = 0.32). No significant rPTT differences were found between subgroups (P = 0.094–0.94). Individual vessel ICC values ranged from 0.58 to 0.97. Data Conclusion: Noninvasive assessment of PH using standard‐of‐care time‐resolved CE‐MRA can detect increased rPTT in PH patients of varying phenotypes compared to controls. Level of Evidence: 1 Technical Efficacy: Stage 3. [ABSTRACT FROM AUTHOR]

Introduction The anterior choroidal artery is a branch of the terminal internal carotid artery (ICA) that is often an incidentally detected anomaly. The hyperplastic variant has been linked with an increased risk of aneurysms. We explore the role of magnetic resonance (MR) angiography in the detection of this variant and its impact of presentation of patients.

Abstract Contrast-enhanced MR angiography (MRA) is a critical technique for vascular imaging. Nevertheless, the efficacy of MRA is often limited by the low rate of relaxation, short blood-circulation time, and metal ion-released potential long-term toxicity of clinical available Gd-based contrast agents. In this work, we report a facile and efficient strategy to achieve Gd-chelated organic nanoparticles with high relaxivity for T 1 -weighted MRA imaging. The Gd-chelated PEG-TCPP nanoparticles (GPT NPs) have been engineered composite structured consisting of Gd-chelated TCPP and PEG. The spherical structure of TCPP offers more chemical sites for Gd3+ coordination to improve the relaxivity and avoid leakage of the Gd3+ ions. The synthesized GPT NPs exhibit a high relaxation rate of 35.76 mM− 1 s− 1 at 3.0 T, which is higher than the rates for most reported MR contrast agents. Therefore, GPT NPs can be used for MRA with much stronger vascular signals, longer circulation time, and high-resolution arterial vascular visualization than those using clinical MR contrast agents at the same dose. This work may make the T 1 MRI contrast agents for high-resolution angiography possible and offer a new candidate for preclinical and clinical applications of MR vascular imaging and vascular disease diagnosis. Graphical Abstract

Magnetic resonance imaging (MRI) is used in patients with sickle cell disease (SCD) to detect silent cerebral infarcts. MR angiography (MRA) can identify arterial stenoses and intracranial aneurysms (ICANs) associated with SCD. In this study, we aimed to estimate the prevalence of ICANs in asymptomatic adult patients with SCD referred from the SCD clinic for routine screening by MRI/MRA using a 3T-MRI scanner. Findings were independently reviewed by two neuroradiologists. Between 2016 and 2020, 245 asymptomatic adults with SCD were stratified according to genotype (SS/S-β0thalassemia and SC/Sβ+). ICANs were found in 27 patients (11%; 0.95 CI: 8–16%). ICANs were more frequent in SS/S-β0thalassemia patients (20/118 or 17%; 0.95 CI: 11–25%) than in SC/βb+ patients (7/127 or 6%; 0.95 CI: 2–11%; p = 0.007). Individuals with SCD (particularly SS/S-β0thalassemia) have a higher prevalence of ICANs than the general population. We believe that MRA should be considered in the current American Society of Hematology guidelines, which already contain a recommendation for MRI at least once in adult SCD patients. However, the clinical significance of preventive treatment of unruptured aneurysms remains controversial. [ABSTRACT FROM AUTHOR]