Perfusion parameter map generation from TOF-MRA in stroke using generative adversarial networks.

PURPOSE: To generate perfusion parameter maps from Time-of-flight magnetic resonance angiography (TOF-MRA) images using artificial intelligence to provide an alternative to traditional perfusion imaging techniques. MATERIALS AND METHODS: This retrospective study included a total of 272 patients with cerebrovascular diseases; 200 with acute stroke (from 2010 to 2018), and 72 with steno-occlusive disease (from 2011 to 2014). For each patient the TOF MRA image and the corresponding Dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) were retrieved from the datasets. The authors propose an adapted generative adversarial network (GAN) architecture, 3D pix2pix GAN, that generates common perfusion maps (CBF, CBV, MTT, TTP, Tmax) from TOF-MRA images. The performance was evaluated by the structural similarity index measure (SSIM). For a subset of 20 patients from the acute stroke dataset, the Dice coefficient was calculated to measure the overlap between the generated and real hypoperfused lesions with a time-to-maximum (Tmax) > 6 s. RESULTS: The GAN model exhibited high visual overlap and performance for all perfusion maps in both datasets: acute stroke (mean SSIM 0.88-0.92, mean PSNR 28.48-30.89, mean MAE 0.02-0.04 and mean NRMSE 0.14-0.37) and steno-occlusive disease patients (mean SSIM 0.83-0.98, mean PSNR 23.62-38.21, mean MAE 0.01-0.05 and mean NRMSE 0.03-0.15). For the overlap analysis for lesions with Tmax>6 s, the median Dice coefficient was 0.49. CONCLUSION: Our AI model can successfully generate perfusion parameter maps from TOF-MRA images, paving the way for a non-invasive alternative for assessing cerebral hemodynamics in cerebrovascular disease patients. This method could impact the stratification of patients with cerebrovascular diseases. Our results warrant more extensive refinement and validation of the method.

Simultaneous brain and neck time-of-flight MRA using spiral multiband with localized quadratic encoding.

PURPOSE: To develop a method that achieves simultaneous brain and neck time-of-flight (ToF) magnetic resonance angiography (MRA) within feasible scan timeframes. METHODS: Localized quadratic (LQ) encoding is efficient for both signal-to-noise ratio (SNR) and in-flow enhancement. We proposed a spiral multiband LQ method to enable simultaneous intracranial and carotid ToF-MRA within a single scan. To address the venous signal contamination that becomes a challenge with multiband (MB) ToF, tilt-optimized non-saturated excitation (TONE) and partial-Fourier slice selection (PFSS) were further introduced in the LQ framework to mitigate the venous signal and improve artery contrast. A sequential spiral MB and LQ reconstruction pipeline was employed to obtain the brain-and-neck image volumes. RESULTS: The proposed MB method was able to achieve simultaneous brain and neck ToF-MRA within a 2:50-min scan. The complementarily boosted SNR-efficiency by MB and LQ acquisitions allows for the increased spatial coverage without increase in scan time or noticeable compromise in SNR. The incorporation of both TONE and PFSS effectively alleviated the venous contamination with improved small vessel sensitivity. Selection of scan parameters such as the LQ factor and flip angle reflected the trade-off among SNR, blood contrast, and venous suppression. CONCLUSIONS: A novel MB spiral LQ approach was proposed to enable fast intracranial and carotid ToF-MRA with minimized venous corruption. The method has shown promise in MRA applications where large spatial coverage is necessary.

Detection of Dolichoectasia and Atherosclerosis by Automated MRA Tortuosity Metrics in a Population-Based Study.

BACKGROUND: Intracranial vessel tortuosity is a key component of dolichoectasia and has been associated with atherosclerosis and adverse neurologic outcomes. However, the evaluation of tortuosity is mainly a descriptive assessment. PURPOSE: To compare the performance of three automated tortuosity metrics (angle metric [AM], distance metric [DM], and distance-to-axis metric [DTA]) for detection of dolichoectasia and presence of segment-specific plaques. STUDY TYPE: Observational, cross-sectional metric assessment. POPULATION: 1899 adults from the general population; mean age = 76 years, female = 59%, and black = 29%. FIELD STRENGTH/SEQUENCE: 3-T, three-dimensional (3D) time-of-flight MRA and 3D vessel wall MRI. ASSESSMENT: Tortuosity metrics and mean luminal area were quantified for designated segments of the internal carotid artery, middle cerebral artery, anterior cerebral artery, posterior cerebral artery, vertebral artery, and entire length of basilar artery (BA). Qualitative interpretations of BA dolichoectasia were assessed based on Smoker's visual criteria. STATISTICAL TESTS: Descriptive statistics (2-sample t-tests, Pearson chi-square tests) for group comparisons. Receiver operating characteristics area under the curve (AUC) for detection of BA dolichoectasia or segment-specific plaque. Model inputs included 1) tortuosity metrics, 2) mean luminal area, and 3) demographics (age, race, and sex). RESULTS: Qualitative dolichoectasia was identified in 336 (18%) participants, and atherosclerotic plaques were detected in 192 (10%) participants. AM-, DM-, and DTA-calculated tortuosity were good individual discriminators of basilar dolichoectasia (AUCs: 0.76, 0.74, and 0.75, respectively), with model performance improving with the mean lumen area: (AUCs: 0.88, 0.87, and 0.87, respectively). Combined characteristics (tortuosity and mean luminal area) identified plaques with better performance in the anterior (AUCs ranging from 0.66 to 0.78) than posterior (AUCs ranging from 0.54 to 0.65) circulation, with all models improving by the addition of demographics (AUCs ranging from 0.62 to 0.84). DATA CONCLUSION: Quantitative vessel tortuosity metrics yield good diagnostic accuracy for the detection of dolichoectasia. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 2.

Quantitative Time-of-Flight Head Magnetic Resonance Angiography of Cerebrovascular Disease.

BACKGROUND: Standard Cartesian time-of-flight (TOF) head magnetic resonance angiography (MRA) is routinely used to evaluate the intracranial arteries, but does not provide quantitative hemodynamic information that is useful for patient risk stratification as well as for monitoring treatment and tracking changes in blood flow over time. Quantitative TOF (qTOF) MRA represents a new and efficient method for simultaneous evaluating the intracranial arteries and quantifying blood flow velocity, but it has not yet been evaluated in patients with cerebrovascular disease. PURPOSE: To evaluate qTOF for simultaneously evaluating the intracranial arteries and quantifying intracranial blood flow velocity in patients with cerebrovascular disease, without the need for a phase contrast (PC) scan. STUDY TYPE: Prospective. SUBJECTS: Twenty-four patients (18 female, 6 male) with cerebrovascular disease. FIELD STRENGTH/SEQUENCES: Head MRA at 3 T using gradient-echo 3D qTOF, standard Cartesian TOF, and PC protocols. ASSESSMENT: Three independent readers assessed arterial image quality using a 4-point scale (1: non-diagnostic, 4: excellent) and artifact presence. Total and component flow velocities obtained with qTOF and PC were measured. STATISTICAL TESTS: Wilcoxon signed-rank tests, Gwet's AC2, intraclass correlation coefficients (ICC) for absolute agreement, Bland-Altman analyses, tests of equal proportions. P values <0.05 were considered statistically significant. RESULTS: Averaged across readers and compared to standard Cartesian TOF, qTOF significantly improved overall arterial image quality (3.8 ± 0.2 vs. 3.6 ± 0.5), image quality at locations of pathology (3.7 ± 0.5 vs. 3.4 ± 0.7), and increased the proportion of evaluations rated without artifacts (63.9% [46/72] vs. 37.5% [27/72]). qTOF significantly agreed with PC for total flow velocity (ICC = 0.71) and component flow velocity (ICC = 0.89). DATA CONCLUSION: qTOF angiography of the head matched or improved upon the image quality of standard Cartesian TOF, reduced image artifacts, and provided quantitative hemodynamic data, without the need for a PC scan. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

There is high variability in quantitative measurement techniques in glenohumeral capsular measurements for shoulder instability: A systematic review.

PURPOSE: Instability of the glenohumeral joint remains a complex clinical issue with high rates of surgical failure and significant morbidity. Advances in specific radiologic measurements involving the glenoid and the humerus have provided insight into glenohumeral pathology, which can be corrected surgically towards improving patient outcomes. The contributions of capsular pathology to ongoing instability remain unclear. The purpose of this study is to provide a systematic review of existing glenohumeral capsular measurement techniques published in the last 15 years. METHODS: A systematic review of multiple databases was performed following PRISMA guidelines for all primary research articles between 2008 and 2023 with quantitative measurements of the glenohumeral capsule in patients with instability, including anterior, posterior and multi-directional instability. RESULTS: There were a total of 14 articles meeting the inclusion criteria. High variability in measurement methodology across studies was observed, including variable amounts of intra-articular contrast, heterogeneity among magnetic resonance sequence acquisitions, differences in measurements performed and the specific approach taken to compute each measurement. CONCLUSION: There is a need for standardization of methods in the measurement of glenohumeral capsular pathology in the setting of glenohumeral instability to allow for cross-study analysis. LEVEL OF EVIDENCE: Level III.

Morphological characterization and interspecific variation among five species of Ziziphus genus to select superiors in Iran.

BACKGROUND: Several species of the genus Ziziphus are used worldwide for their medicinal and therapeutic properties. The present study aimed to investigate the phenotypic variation of five species of the Ziziphus genus, including Z. jujuba Mill. (25 accessions), Z. mauritiana Lam. (25 accessions), Z. spina-christi L. (25 accessions), Z. nummularia L. (10 accessions), and Z. xylopyrus Willd. (10 accessions) from Markazi, Sistan-va-Baluchestan, and Khuzestan provinces, Iran. RESULTS: The investigated accessions have significant differences in terms of all the measured as revealed using analysis of variance (ANOVA, P < 0.01). The range of fruit weight was 0.43-1.29 g in Z. jujuba, 17.85-29.87 g in Z. mauritiana, 0.94-3.44 g in Z. spina-christi, 0.93-2.02 g in Z. nummularia, and 0.91-3.02 g in Z. xylopyrus. All the measured traits showed significant and positive correlations with each other. Multiple regression analysis (MRA) results showed that fruit length, stone width, stone weight, stone length, and fruit width have significant effects on fruit weight, and thus their fluctuations have a significant effect on increasing or decreasing fruit weight. The accessions were grouped into two main clusters using hierarchical cluster analysis. The first cluster (I) included all the accessions of Z. mauritiana, while the second cluster (II) contained the accessions of the rest species forming two sub-clusters. CONCLUSION: Based on the commercial characters, accessions no. 12, 13, 17, 23, and 24 in Z. jujuba, accessions no. 3, 9, 17, 18, 20, 22, and 23 in Z. mauritiana, accessions no. 5, 6, 8, 13, 19, 22, and 24 in Z. spina-christi, accessions no. 3, 7, and 9 in Z. nummularia, and accessions no. 2, 4, 7, and 10 in Z. oxyphylla showed the highest fruit weight and thus can be suggested as superior for cultivation or use in breeding programs due to having larger fruits.

Spiral inflow MRA with sliding-slice localized quadratic encoding.

PURPOSE: This work proposes a 2D/3D hybrid inflow MRA technique for fast scanning and high SNR and contrast-to-noise (CNR) efficiencies. METHODS: Localized quadratic (LQ) encoding was combined with a sliding-slice spiral acquisition. Inflow MRAs around the circle of Willis and the carotid bifurcations were collected on four healthy volunteers. Spiral images were deblurred without or with water-fat separation for sliding-slice LQ (ssLQ) out-of-phase (OP) and Dixon inflow MRAs, respectively. Results were compared to multiple overlapping thin slab acquisitions (MOTSA) and 2D OP inflow MRAs. Noise data were also acquired with RF and gradients turned off to compute maps of SNR and SNR efficiency. Quantitative assessment of relative contrast, CNR, and CNR efficiency for flow were performed in regions of interest. RESULTS: The sliding-slice spiral technique alone reduces scan time by 10% to 40% compared with a standard spiral acquisition scheme. The proposed spiral ssLQ OP achieves 50% higher scan speed than the spiral MOTSA with comparable SNR and CNR efficiencies, which are ∼100% higher than the Cartesian MOTSA for intracranial inflow MRAs. Spiral ssLQ Dixon inflow MRA provides better visibility for vessels around the fat compared to spiral ssLQ OP inflow MRA, with a trade-off of scan speed. Spiral ssLQ MRA with thinner slice thickness is two to five times faster than the 2D Cartesian inflow neck MRA around the carotid bifurcations, while also achieving higher SNR efficiency. CONCLUSION: The proposed spiral ssLQ is a fast and flexible MRA method with improved SNR and CNR efficiencies over traditional Cartesian inflow MRAs.

Optimizing the diagnostic approach of functional popliteal artery entrapment syndrome.

OBJECTIVE: Functional popliteal artery entrapment syndrome (fPAES) is an underdiagnosed and undertreated etiology of atypical claudication. Symptoms of fPAES include deep posterior muscle cramping and pain with exercise and, unlike anatomic PAES, there are seldom vascular complications. Common noninvasive diagnostic modalities include ankle-brachial index, arterial duplex Doppler ultrasound (DUS) examination, and cross-sectional imaging such as magnetic resonance angiography (MRA). Entrapment can be difficult to reproduce during diagnostic testing, requiring provocative maneuvers. Because we believed different provocative maneuvers provide different diagnostic efficacy, we sought to optimize our diagnostic approach to fPAES. METHODS: We performed a retrospective review of patients before and after optimizing our noninvasive imaging protocol comparing patients with fPAES versus other atypical claudicants with chronic compartment syndrome. RESULTS: Arterial DUS examination and exercise ankle-brachial index were important components of our protocol with a significant decrease in systolic posterior tibial blood pressure of -14 mm Hg after exercise, whereas nonentrapment release patients had an overall increase of 8 mm Hg (P = .006). Arterial DUS examination of the distal PA with forced plantarflexion demonstrated a trend toward an increase in the measured velocity ratio, especially in the middle and distal PA. MRA with stressed plantar flexion findings were positive in 6 of 11 patients with fPAES, with false negatives likely owing to patients' inability to maintain a provocative position for the duration of the MRA. CONCLUSIONS: Diagnosing fPAES is challenging owing to a lack of standardized diagnostic testing and provocative maneuvers. Different maneuvers demonstrated varying diagnostic yields for fPAES. Exercise ABIs were the most reliable vascular laboratory test to detect changes attributable to fPAES and to distinguish it from chronic compartment syndrome. Segmental PA DUS examination seems to be promising as a means of detecting PA impingement. Stress positional MRA effectively demonstrates anatomic PAES, but has a false-negative rate for fPAES.

Spatially and velocity-selective magnetization preparation for noncontrast-enhanced peripheral MR angiography.

The purpose of the current study was to develop spatially and velocity-selective (SVS) magnetization preparation pulses for noncontrast-enhanced peripheral MR angiography (MRA) to provide comparisons with velocity-selective (VS) MRA with comparison to velocity-selective (VS). VS preparation pulses were designed by concatenating multiple excitation steps, each of which was a combination of a hard RF pulse, VS unipolar gradient pulses, and refocusing RF pulses. SVS preparation pulses were designed by replacing the hard RF pulse with a sinc-shaped RF pulse combined with a symmetric tripolar gradient pulse (which does not perturb the velocity encoding by the VS unipolar gradient pulses). Numerical simulations were performed to verify the intended hybrid excitation selectivity of SVS pulses taking account of tissue relaxation, magnetic field errors, and eddy currents. In vivo experiments were performed in healthy subjects to verify the hybrid excitation selectivity, as well as to demonstrate the visualization of the entire peripheral arteries using six-station protocols. As demonstrated by numerical simulations, SVS preparation yielded a notch-shaped longitudinal magnetization (Mz )-velocity response within the spatial stopband (the same as VS preparation) and preserved the Mz of spins outside the stopband, regardless of its velocity. We confirmed these observations also through in vivo tests with good agreement in normalized arterial and muscle signal intensities. In six-station peripheral MRA experiments, the proposed SVS-MRA yielded significantly higher arterial signal-to-noise ratio (SNR) (51.6 ± 14.3 vs. 38.9 ± 10.9; p < 0.001) and contrast-to-noise ratio (CNR) (41.2 ± 13.0 vs. 31.3 ± 10.5; p < 0.001) compared with VS-MRA. The proposed SVS-MRA improves arterial SNR and CNR compared with VS-MRA by mitigating undesired presaturation of arterial blood upstream the imaging field of view.

Quantitative Assessment of Regional Pulmonary Transit Times in Pulmonary Hypertension.

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.

Non-steroidal mineralocorticoid receptor antagonists and cardiorenal outcomes in chronic kidney disease.

The burden of adverse cardiorenal outcomes among patients with the trifecta of diabetes, heart failure (HF) and chronic kidney disease (CKD) remains high. Steroidal mineralocorticoid receptor antagonists (MRAs) have been shown to improve clinical outcomes in patients with HF, however, there is significant underutilization of these agents, especially in patients with advanced CKD. Non-steroidal MRAs are an emerging therapeutic option for patients with diabetic kidney disease and are now guideline-supported in this population. Non-steroidal MRAs have a unique pharmacological profile distinct from their steroidal counterparts that retains the class-specific cardiorenal benefits but may help mitigate adverse effects, especially hyperkalaemia, in patients with CKD. In this review we summarize the current evidence on the use of non-steroidal MRAs for improving cardiorenal outcomes in patients with CKD and diabetes, as well as for combination use alongside other foundational medical therapies used in HF and CKD.

MRA as the Preferred Test for Pulmonary Embolism During the Iodinated Contrast Media Shortage of 2022: A Single-Center Experience.

BACKGROUND. Closure of a GE Healthcare facility in Shanghai, China, in 2022 disrupted the iodinated contrast media supply. Technologic advances have addressed limitations associated with the use of pulmonary MRA for diagnosis of pulmonary embolism (PE). OBJECTIVE. The purpose of this study was to describe a single institution's experience in the use of pulmonary MRA as an alternative to CTA for the diagnosis of PE in the general population during the iodinated contrast media shortage in 2022. METHODS. This retrospective single-center study included all CTA and MRA examinations performed to exclude PE from April 1 through July 31 (18 weekly periods) in 2019 (before the COVID-19 pandemic and contrast media shortage), 2021 (during the pandemic but before the shortage), and 2022 (during both the pandemic and the shortage). From early May through mid-July of 2022, MRA served as the preferred test for PE diagnosis, to preserve iodinated contrast media. CTA and MRA reports were reviewed. The total savings in iodinated contrast media volume resulting from preferred use of MRA was estimated. RESULTS. The study included 4491 examinations of 4006 patients (mean age, 57 ± 18 [SD] years; 1715 men, 2291 women): 1245 examinations (1111 CTA, 134 MRA) in 2019, 1547 examinations (1403 CTA, 144 MRA) in 2021, and 1699 examinations (1282 CTA, 417 MRA) in 2022. In 2022, the number of MRA examinations was four (nine when normalized to a 7-day period) in week 1, and this number increased to a maximum of 63 in week 10 and then decreased to 10 in week 18. During weeks 8-11, more MRA examinations (range, 45-63 examinations) than CTA examinations (range, 27-46 examinations) were performed. In 2022, seven patients with negative MRA underwent subsequent CTA within 2 weeks; CTA was negative in all cases. In 2022, 13.9% of CTA examinations (vs 10.3% of MRA examinations) were reported as having limited image quality. The estimated 4-month savings resulting from preferred use of MRA in 2022, under the assumption of uniform simple linear growth in CTA utilization annually and a CTA dose of 1 mL/kg, was 27 L of iohexol (350 mg I/mL). CONCLUSION. Preferred use of pulmonary MRA for PE diagnosis in the general population helped to conserve iodinated contrast media during the 2022 shortage. CLINICAL IMPACT. This single-center experience shows pulmonary MRA to be a practical substitute for pulmonary CTA in emergency settings.

Meta-Analysis Evaluating Risk of Hyperkalemia Stratified by Baseline MRA Usage in Patients with Heart Failure Receiving SGLT2 Inhibitors.

BACKGROUND: Both mineralocorticoid receptor antagonists (MRAs) and sodium-glucose co-transporter type 2 inhibitors (SGLT2is) have demonstrated beneficial reductions in cardiovascular outcomes. However, the risk of precipitating hyperkalemia with their concomitant usage remains unclear. METHODS: MEDLINE and Cochrane were searched from inception through March 2022. Randomized controlled trials on patients with heart failure (HF) evaluating the effect of SGLT2is on clinical outcomes between MRA users and non-users were considered for inclusion. Outcomes of interest were mild and moderate/severe hyperkalemia, for which hazard ratios (HR) were pooled using a random effects model. RESULTS: From the 972 articles retrieved from the initial search, three RCTs (n = 14,462 patients) were included in our meta-analysis. Pooled analysis demonstrated no significant difference in the incidence of mild hyperkalemia between MRA users (HR 0.82 [0.70-0.97]) and non-users (HR 0.95 [0.77-1.17]) (P-interaction = 0.28). The risk of severe hyperkalemia was significantly decreased in MRA users (HR 0.59 [0.44-0.78]; p = 0.0002; I2 = 0%) but not in non-users (HR 0.76 [0.56-1.02]; p = 0.07; I2 = 0%) (P-interaction = 0.22). Sensitivity analysis including patients with HF with reduced ejection fraction (HFrEF) revealed similar results across all subgroups, but no significant reduction in the incidence of mild hyperkalemia (HR 0.89 [0.76-1.04] was noted in MRA users with HFrEF. CONCLUSION: MRAs reduced the risk of mild or moderate/severe hyperkalemia, when added to SGLT2is. Future clinical trials should target scrupulous assessment of the risk of mild and moderate/severe hyperkalemia when used concomitantly with MRAs.

Value of CTA/MRA in the setting of intraparenchymal hemorrhage in the emergency department.

PURPOSE: To assess the diagnostic yield of computed tomography angiography (CTA)/magnetic resonance angiography (MRA) brain and neck ordered in the emergency department (ED) for patients who have intraparenchymal hemorrhage (IPH) on their initial noncontrast CT (NCCT) of the head. METHODS: In this retrospective study, we reviewed 156 patients presenting to the ED with nontraumatic IPH, documented on NCCT. We assessed if the subsequent CTA/MRA was positive, and collected data regarding the location of the bleed, patients' age group, and presence/absence of associated SAH/IVH. Two neuroradiologists were asked to predict, based on age and NCCT appearance, whether the CTA/MRA would be positive or negative for demonstrating a vascular etiology of the hemorrhage. RESULTS: The yield of CTA/MRA head for patients above 75 years old was 2% (1/49), as the etiology for IPH in such age group was more commonly related to hypertensive bleed or amyloid angiopathy. The concomitant presence of subarachnoid hemorrhage (SAH) and intraventricular hemorrhage (IVH), particularly in patients younger than 75 years, correlated with a higher likelihood of a positive CTA. Statistically, the neuroradiologists were able to exclude a vascular source of the IPH based on CT appearance, bleed location, and patient's age in over 92% of cases. CONCLUSION: CTA/MRA for IPH has a lower yield in patients at older age and with deep gray matter distribution without SAH. Neuroradiologists were accurate at excluding a vascular source of the IPH in most cases. This study suggests that CTA/MRA can be omitted in certain scenarios, thereby preventing overutilization, and leading to optimal use of health care resources.

Moyamoya disease in an adolescent with subarachnoid hemorrhage: a case report.

PURPOSE/AIM OF THE STUDY: This study aims to present a case of Moyamoya disease (MMD) in an adolescent who experienced a subarachnoid hemorrhage (SAH). The purpose is to underscore the importance of considering MMD as a potential cause of SAH in adolescents, particularly in the absence of common causes such as trauma or aneurysmal rupture. The case further highlights the significance of early identification and appropriate management to prevent further complications and improve patient outcomes. MATERIALS AND METHODS: The diagnosis was initially based on findings from a CT angiography and later confirmed through magnetic resonance angiography (MRA) and magnetic resonance imaging (MRI). RESULTS: The case study demonstrates the effectiveness of utilizing MRA and MRI in diagnosing MMD in adolescents. It emphasizes the challenges in areas with limited resources where advanced imaging techniques like digital subtraction angiography (DSA) may not be readily accessible or affordable. The gold standard for MMD diagnosis, DSA, is acknowledged, but the study underscores the importance of alternative imaging methods in resource-constrained settings. CONCLUSION: In conclusion, this case underscores the importance of considering Moyamoya disease as a potential etiology for subarachnoid hemorrhage in adolescents, particularly when common causes are absent. The study highlights the crucial role of MRA and MRI in the diagnosis of MMD, emphasizing their significance in areas with limited resources. Early identification and appropriate management are essential for preventing complications and improving patient outcomes, acknowledging the challenges associated with the accessibility of gold standard diagnostic techniques in certain settings.

Does needle penetration of the shoulder joint prior to arthroscopy increase infection risk? The effect of preoperative magnetic resonance arthrogram or corticosteroid injection.

BACKGROUND: Prior literature has associated preoperative corticosteroid shoulder injection (CSI) with infection following shoulder surgery. A recent study found an equally elevated risk of total knee arthroplasty infection with preoperative injection of either CSI or hyaluronic acid. The implication is that violation of a joint prior to surgery, even in the absence of corticosteroid, may pose an elevated risk of infection following orthopedic surgery. The aim of the present study was to determine whether violation of the shoulder joint for magnetic resonance arthrogram (MRA) poses an elevated risk of infection following shoulder arthroscopy, and to compare this risk to that introduced by preoperative CSI. METHODS: A national, all-payer database was queried to identify patients undergoing shoulder arthroscopy between January 2015 and October 2020. Patients were stratified into the following groups: (1) no CSI or MRA within 6 months of surgery (n = 5000), (2) CSI within 2 weeks of surgery (n = 1055), (3) CSI between 2 and 4 weeks prior to surgery (n = 2575), (4) MRA within 2 weeks of surgery (n = 414), and (5) MRA between 2 and 4 weeks prior to surgery (n = 1138). Postoperative infection (septic shoulder or surgical site infection) was analyzed at 90 days, 1 year, and 2 years, postoperatively. Multivariable logistic regression analysis controlled for differences among groups. RESULTS: MRA within 2 weeks prior to shoulder surgery was associated with an increased risk of infection at 1 year (odds ratio [OR], 2.17; P = .007), while MRA 2-4 weeks preceding surgery was not associated with an increased risk of postoperative infection at any time point. By comparison, CSI within 2 weeks prior to surgery was associated with an increased risk of postoperative infection at 90 days (OR, 1.72; P = .022), 1 year (OR, 1.65; P = .005), and 2 years (OR, 1.63; P = .002) following surgery. Similarly, CSI 2-4 weeks prior to surgery was associated with an increased risk of postoperative infection at 90 days (OR, 1.83; P < .001), 1 year (OR, 1.62; P < .001), and 2 years (OR, 1.79; P < .001). CONCLUSION: Preoperative CSI within 4 weeks of shoulder arthroscopy elevates the risk of postoperative infection. Needle arthrotomy for shoulder MRA elevates the risk of infection in a more limited fashion. Avoidance of MRA within 2 weeks of shoulder arthroscopy may mitigate postoperative infection risk. Additionally, the association between preoperative CSI and postoperative infection may be more attributed to medication profile than to needle arthrotomy.

Acute phase supra-aortic intraluminal thrombus signal changes on magnetic resonance angiography: A case series: Intraluminal thrombus signal changes on MRA.

BACKGROUND AND OBJECTIVES: Intraluminal thrombus (ILT) is a relatively rare cause of stroke. MRI/MRA is increasingly used for stroke patients eligible for acute treatment. Radiological ILT characteristics have never been studied systematically on MRA. We aimed to analyse signal changes and other radiological characteristics of ILT in the acute phase on MRA in a case series of ILT patients. MATERIALS AND METHODS: Consecutive stroke patients registered in our stroke database between January 2013 and September 2022 were screened for supra-aortic ILT on MRA, in whom MRA was the first supra-aortic vessel imaging performed. Twelve patients were included for analysis. Radiological analysis on MRA included ILT localisation, diameter of the free-floating ILT component, total ITL length, degree of stenosis caused by ILT, and ILT signal intensity. RESULTS: Median age was 65 years and 92% were men. Median time interval between stroke onset and MRA was 0.5 days. Atherosclerosis was the underlying ILT aetiology in half of the patients. The most frequent ILT localisation was the internal carotid artery, always involving the C1 segment. Median ILT diameter was 4.35 mm, median length 20.9 mm, median stenosis 65%, and with a homogeneous hypointensity of the ILT in 67% and a mixed hypo-hyperintensity in 33% (with ILT showing central hyperintensity surrounded by peripheral hypointensity). DISCUSSION: When observed on MRA, ILT showed a homogeneous hypointensity in two-thirds and a mixed hypo-hyperintensity in one third of patients. In future studies, follow-up MRA scans should be performed to analyse whether these signal changes are time-related or influenced by antithrombotic treatment for ILT.

Anatomical information of the lenticulostriate arteries on high-resolution 3D-TOF MRA at 3 T: comparison with 3D-DSA.

PURPOSE: As the lenticulostriate arteries (LSAs) perfuse neurologically important areas, it is necessary to accurately assess the origin and number of the LSAs before surgery. Although three-dimensional time-of-flight MR angiography (3D-TOF MRA) is a non-invasive procedure, it requires high-resolution (HR) images to depict the LSAs with a small diameter. Therefore, we performed 3D-TOF MRA with the maximum HR (HR-MRA) using a 3 T scanner to examine whether a good depiction of the LSAs, equivalent to that of digital subtraction angiography (DSA), could be obtained. METHODS: Our study group comprised 16 consecutive patients who underwent HR-MRA and 3D-DSA. In both studies, we evaluated the localization of the origin from M1, M2, or A1 segments, their number of stems, and depiction. RESULTS: There was no significant difference in the visualization of the LSAs between HR-MRA and 3D-DSA (P values; M1, M2, and A1 = 0.39, 0.69, and 0.69, respectively), and both the number of stems and the localization of the origin of the LSAs corresponded between the two examinations. CONCLUSION: HR-MRA at 3 T can depict the LSA well. It reveals the number of the LSA stems and the LSA origin comparatively with DSA.

Posterior spinal artery infarct.

Posterior spinal artery syndrome has a variable presentation and often poses a clinical challenge. We describe an acute posterior spinal artery syndrome in a man in his 60s with vascular risk factors, who presented with altered sensation in the left arm and left side of his torso but with normal tone, strength and deep tendon reflexes. MR imaging showed a left paracentral T2 hyperintense area affecting the posterior spinal cord at the level of C1. Diffusion-weighted MRI (DWI) showed high signal intensity in the same location. He was medically managed as having ischaemic stroke and made a good recovery. Three-month MRI follow-up showed a persisting T2 lesion but the DWI changes had resolved, consistent with the time course for infarction. Posterior spinal artery stroke has a variable presentation and is probably under-recognised clinically, requiring careful attention to MR imaging for its diagnosis.

Optimization of undersampling parameters for 3D intracranial compressed sensing MR angiography at 7 T.

PURPOSE: 3D time-of-flight MRA can accurately visualize the intracranial vasculature but is limited by long acquisition times. Compressed sensing reconstruction can be used to substantially accelerate acquisitions. The quality of those reconstructions depends on the undersampling patterns used. In this work, we optimize sets of undersampling parameters for various acceleration factors of Cartesian 3D time-of-flight MRA. METHODS: Fully sampled datasets, acquired at 7 Tesla, were retrospectively undersampled using variable-density Poisson disk sampling with various autocalibration region sizes, polynomial orders, and acceleration factors. The accuracy of reconstructions from the different undersampled datasets was assessed using the vessel-masked structural similarity index. Identified optimal undersampling parameters were then evaluated in additional prospectively undersampled datasets. Compressed sensing reconstruction parameters were chosen based on a preliminary reconstruction parameter optimization. RESULTS: For all acceleration factors, using a fully sampled calibration area of 12 × 12 k-space lines and a polynomial order of 2 resulted in the highest image quality. The importance of parameter optimization of the sampling was found to increase for higher acceleration factors. The results were consistent across resolutions and regions of interest with vessels of varying sizes and tortuosity. The number of visible small vessels increased by 7.0% and 14.2% when compared to standard parameters for acceleration factors of 7.2 and 15, respectively. CONCLUSION: The image quality of compressed sensing time-of-flight MRA can be improved by appropriate choice of undersampling parameters. The optimized sets of parameters are independent of the acceleration factor and enable a larger number of vessels to be visualized.