Magnetic Resonance Imaging Angiography Research Articles

Staged cluster transformers for intracranial aneurysms segmentation from structure fused 3D MRA

AbstractIntracranial aneurysms (IAs) manifest as atypical dilatation within the intracranial arterial structures, the rupture of which accounts for high mortality and morbidity rates. Current clinical protocols require radiologists to manually annotate IAs on Magnetic Resonance Angiography (MRA) images, which is inherently subjective and time‐consuming. Given these limitations, there is an urgent need to explore methods for automated and accurate segmentation of IAs from MRA images. In particular, recent years have witnessed the proliferation of sophisticated computational techniques, with deep learning algorithms—especially the 3D U‐Net and its derivatives—gaining prominence in segmentation works. Nevertheless, convolutional neural network (CNN)‐based models have an inherent limitation in capturing long‐range spatial dependencies, which inadvertently compromises the retention of global features critical for segmentation. In response to this challenge, we introduce an avant‐garde architectural design, dubbed staged cluster transformers (SCTR), which incorporates cluster mechanism into vision transformers to perform volumetric MRA image segmentation. In addition to the MRA clustering branch, the spatially aligned brain Magnetic Resonance Imaging (MRI) representation branch is also combined to extract the structural features and assist the network in learning richer contextual and boundary information for accurate voxel prediction. For validation, we utilized both a publicly available challenge dataset and an internal clinical dataset in this study. Our proposed model achieves dice similarity coefficients (DSC) of 0.5587 and 0.8110 on these two datasets, respectively, outperforming other state‐of‐the‐art approaches. The results suggest that SCTR is a promising method for automatic segmentation of IAs. Our code is available at https://github.com/guolilin/SCTR.

Bilateral Ocular Ischaemic Syndrome due to Carotid Artery and Cardiovascular Disease: A Case Report

Introduction : Ocular ischemic syndrome (OIS) is a rare but potentially blinding and fatal condition caused by carotid artery disease or other systemic condition results in ocular hypoperfusion.
 Case Illustration : A 62-year-old male with sudden bilateral vision loss, swelling, redness and pain of both eye for 7 days. There were dilated conjunctival and episcleral vessels, visual acuity of the right eye was hand movement and 0.05 for left eye, intraocular pressure (IOP) was 33 mmHg in right eye and 37 mmHgfor left eye. Anterior segment evaluation revealed rubeosis iris, mild anterior chamber reaction, and temporal angle neovascularization on gonioscopy. Both direct and consensual light reflexes were sluggish. Fundus examination showed normal optic disc, minimal hemorrhages at mid-periphery, narrowed arterioles, and minimal cotton wool spot. Macular OCT demonstrated discrete hyperreflectivity of inner retinal layers. From Macular Angiography OCT, ETDRS Central vessel density were 11.2% and 17.6% for the right eye and left eye, respectively. In both eyes, paracentesisof anterior chamber, intravitreal and intracameral injections of anti-VEGF were performed. Brain Magnetic Resonance Angiography Imaging revealed moderate stenosis of both distal carotid artery circulation. Percutaneous Coronary Angiography showed extensive stenosis in coronary artery, with low Ejection Fraction.
 Discussion : For the cardiovascular management, a pacemaker was implanted. One week after procedure, BCVA were 1/60 and 0.15, and IOPs of 17 and 18 mmHg, for the right and left eye, respectively. The patient was scheduled to have laser retinal photocoagulation.
 Conclusion : Quick clinical diagnosis, targeted workup for systemic associations, and prompt treatment might preserve life and sight in OIS.

Visual manifestations in giant cell arteritis: identification of risk factors from the ARTESER Registry.

To determine the prevalence and predictive factors of visual manifestations in a large registry of patients with GCA. ARTESER is a large Spanish multicentre registry supported by the Spanish Society of Rheumatology. It includes patients with GCA from across the entire country diagnosed between June 2013 and March 2019. The variables collected at diagnosis were demographics, clinical manifestations (including all visual manifestations), laboratory, temporal artery biopsy, and imaging findings (ultrasound, FDG-PET/CT, MRI angiography, CT angiography). Patients with and without visual involvement were compared in a bivariate analysis. Multivariate logistic regression was performed to determine potential predictive factors of visual manifestations. The study population comprised 1636 GCA patients, of whom 599 (36.6%) presented visual manifestations. Anterior ischemic optic neuropathy was the most frequent (n = 274 of 599; 45.7%) ocular complication. The independent predictors that increased the risk (OR; 95% confidence interval) of visual involvement were older age (1.027; 1.009-1.045) and jaw claudication (1.724; 1.325-2.243). The variables associated with a reduced risk were polymyalgia rheumatica (0.541; 0.414-0.708), fever (0.373; 0.264-0.527), longer symptom duration (0.946; 0.909-0.985), and higher erythrocyte sedimentation rate (ESR) (0.992; 0.988-0.997), common features of patients with large vessel-GCA. One-third of GCA patients present visual manifestations at diagnosis. Older age and jaw claudication are independent predictors of visual manifestations, whereas polymyalgia rheumatica, fever, longer symptom duration, and high ESR reduce the risk of visual involvement.

Comparing flow and pulmonary artery growth post-patent ductus arteriosus stenting in patients with ductal-dependent pulmonary flow using 4D magnetic resonance imaging.

The 4D magnetic resonance imaging (4D-flow MRI) provides a qualitative and quantitative assessment of cardiovascular structures and processes. 4D-flow MRI was used to study pulmonary flow in post-patent ductus arteriosus (PDA) stent insertion in duct-dependent pulmonary flow neonates at baseline (PDA stent insertion) and after 6 months, and also, to evaluate the effect of flow dynamics on the growth of pulmonary arteries (PAs). This prospective observational study included neonates with ductus arteriosus-dependent pulmonary circulation who underwent ductal stenting between June 2021 and November 2022. Cardiac 4D-flow MRI and magnetic resonance angiography were conducted in two phases; after the deployment of the PDA stent during the neonatal period and after 6 months from stent deployment. Eight neonates were recruited, but only five completed both scans. A total of 10 PAs were evaluated during each phase. The median left PA (LPA) and right PA (RPA) diameters and indexed flow for LPA and RPA were evaluated. The growth rate of LPA was observed to be lower than that of RPA (percentage diameter increase: 74 vs. 153%). LPA Z-score was lower than RPA. Indexed flow in both LPA and RPA showed a reduction in the 6-month scan, which was consistent with reduced stent patency. 4D-flow cardiac MRI showed different growth rates and reduced flow between LPA and RPA post-PDA stent. These insights can aid in future management decisions.

Therapeutic small molecules in the development of treatment for subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a severe and often fatal condition characterized by the accumulation of blood beneath the arachnoid layer of the meninges. Predominantly affecting individuals in the 40–60 age range, it is commonly caused by head trauma from falls or car accidents. Ruptures of cerebral aneurysms also contribute significantly to SAH. Risk factors for SAH include hypertension and smoking, and symptoms typically include severe headache and neck pain. Diagnosing SAH typically involves a combination of medical history, physical examination, and imaging studies such as computed tomography angiography or magnetic resonance imaging angiography. Recent research suggests that pharmaceutical management of intracerebral hemorrhage (ICH) includes the administration of recombinant activated factor VII, tranexamic acid, and aggressive blood pressure reduction. For patients with significant SAH and ICH, minimally invasive surgical procedures for hematoma evacuation, as well as surgical evacuation of SAH and ICH, have proven to be highly beneficial. Furthermore, an emerging area of treatment involves therapeutic small molecules designed to interrupt the pathophysiological pathways leading to SAH. This novel approach holds promise for advancing our understanding and management of this complex medical condition.

3D Transcranial ultrasound localization microscopy reveals major arteries in the sheep brain.

Cerebral circulation ensures the proper functioning of the entire human body, and its interruption, i.e. stroke, leads to irreversible damage. However, tools for observing cerebral circulation are still lacking. Although MRI and CT scans serve as conventional methods, their accessibility remains a challenge, prompting exploration into alternative, portable, and non-ionizing imaging solutions like ultrasound with reduced costs. While Ultrasound Localization Microscopy (ULM) displays potential in high-resolution vessel imaging, its 2D constraints limit its emergency utility. This study delves into the feasibility of 3D ULM with multiplexed probe for transcranial vessel imaging in sheep brains, emulating human skull characteristics. Three sheep underwent 3D ULM imaging, compared with angiographic MRI, while skull characterization was conducted in vivo using ultrashort bone MRI sequences and ex vivo via micro CT. The study showcased 3D ULM's ability to highlight vessels, down to the Circle of Willis, yet within a confined 3D field-of-view. Future enhancements in signal, aberration correction, and human trials hold promise for a portable, volumetric, transcranial ultrasound angiography system.

Robust Fast Inter-Bin Image Registration for Undersampled Coronary MRI Based on a Learned Motion Prior.

To propose a 3D nonrigid registration method that accurately estimates the 3D displacement field from artifact-corrupted Coronary Magnetic Resonance Angiography (CMRA) images. We developed a novel registration framework for registration of artifact-corrupted images based on a 3D U-Net initializer and a deep unrolling network. By leveraging a supervised learning framework with training labels estimated from fully-sampled images, the unrolling network learns a task-specific motion prior which reduces motion estimation biases caused by undersampling artifacts in the source images. We evaluated the proposed method, UNROLL, against an iterative Free-Form Deformation (FFD) registration method and a recently proposed Respiratory Motion Estimation network (RespME-net) for 6-fold (in-distribution) and 11-fold (out-of-distribution) accelerated CMRA. Compared to the baseline methods, UNROLL improved both the accuracy of motion estimation and the quality of motion-compensated CMRA reconstruction at 6-fold acceleration. Furthermore, even at 11-fold acceleration, which was not included during training, UNROLL still generated more accurate displacement fields than the baseline methods. The computational time of UNROLL for the whole 3D volume was only 2 seconds. By incorporating a learned respiratory motion prior, the proposed method achieves highly accurate motion estimation despite the large acceleration. This work introduces a fast and accurate method to estimate the displacement field from low-quality source images. It has the potential to significantly improve the quality of motion-compensated reconstruction for highly accelerated 3D CMRA.

Exploring the impact of super-resolution deep learning on MR angiography image quality.

The aim of this study is to assess the effect of super-resolution deep learning-based reconstruction (SR-DLR), which uses k-space properties, on image quality of intracranial time-of-flight (TOF) magnetic resonance angiography (MRA) at 3 T. This retrospective study involved 35 patients who underwent intracranial TOF-MRA using a 3-T MRI system with SR-DLR based on k-space properties in October and November 2022. We reconstructed MRA with SR-DLR (matrix = 1008 × 1008) and MRA without SR-DLR (matrix = 336 × 336). We measured the signal-to-noise ratio (SNR), contrast, and contrast-to-noise ratio (CNR) in the basilar artery (BA) and the anterior cerebral artery (ACA) and the sharpness of the posterior cerebral artery (PCA) using the slope of the signal intensity profile curve at the half-peak points. Two radiologists evaluated image noise, artifacts, contrast, sharpness, and overall image quality of the two image types using a 4-point scale. We compared quantitative and qualitative scores between images with and without SR-DLR using the Wilcoxon signed-rank test. The SNRs, contrasts, and CNRs were all significantly higher in images with SR-DLR than those without SR-DLR (p < 0.001). The slope was significantly greater in images with SR-DLR than those without SR-DLR (p < 0.001). The qualitative scores in MRAs with SR-DLR were all significantly higher than MRAs without SR-DLR (p < 0.001). SR-DLR with k-space properties can offer the benefits of increased spatial resolution without the associated drawbacks of longer scan times and reduced SNR and CNR in intracranial MRA.

Clinical Characteristics of Immediate Contralateral Ischemia Subsequent to Revascularization for Moyamoya Disease

Moyamoya disease is a bilateral steno-occlusive disease involving the cerebral vasculature. While some patients are affected by procedure-related ipsilateral ischemia, ischemic complications contralateral to the revascularization are rarely observed. We retrospectively investigated 135 hemispheres (103 patients) that underwent revascularization in our institution between April 2006 and September 2022. Revascularization surgery comprised single superficial temporal artery-middle cerebral artery anastomosis and encephalo-myo-synangiosis. Certain patients aged under 10years underwent indirect revascularization. Bilateral revascularization was performed with an interval of >3months. Medical records and neuroimages were reviewed, and patients with contralateral ischemic complications were identified. Some cases underwent genetic analysis. The mean age was 34.5 (range: 5-71) years, and 95 cases (70.4%) were in women. Of the 102 cases examined for the RNF213 c.14429G > A (p.Arg4810Lys) variant, 33 (32.4%) and 69 (67.6%) showed the GG and GA genotype, respectively. Three cases (2.2%, all female, age range 44-71years) were complicated with contralateral infarction. The infarcted area distributions of the 2 cases with RNF213 c.14429G > A variant were patchy and peripheral. Theother case showed on magnetic resonance imaging (MRI) angiography total occlusion of the internal carotidartery where patency had been confirmed preoperatively. Contralateral ischemia after revascularization occurred in 2.2% of cases. We classified them into peripheral and central types: peripheral type, an infarction owing to hemodynamic insufficiency or intracranial blood flow redistribution; central type, total occlusion of the contralateral internal carotid artery. Intensive preoperative management can minimize the risk of peripheral types, and neurosurgeons should beware of severe central types.

Debris generated by laser and/or balloon cause cerebral infarction with different severity.

The purpose of this study is to determine the effects that debris generated by laser and/or balloon on the brain. Debris generated by laser, balloon, and laser combined with balloon were collected and then injected into rats' left common carotid artery. Rats were divided into five groups: sham, saline, laser (L), balloon (B), and laser combined with balloon (LB). The cognition ability of rats was evaluated by Morris water maze. Cerebral blood flow (CBF) was examined by laser speckle. TTC staining and MRI scan were conducted to detect cerebral ischemic infarction. Intracranial arteries in rats were visualized by MRI angiography via contrast medium injected via tail vein. Immunohistologic staining for NeuN and Iba1 and hematoxylin-eosin staining were performed to assess brain infarction. White matter demyelination was assessed by Luxol fast blue staining. Long-term memory and CBF of rats in different groups exhibited no significant difference. No obstruction sign in intracranial artery tree was noticed in each group. Debris generated by different treatments all caused brain infarction. Infarction lesion caused by debris produced by balloon was much more severe than the one caused by debris generated by laser. While the LB group lay in between. The thickness of white matter decreased in the B group, but not in the L and LB groups. Rat brain has a tolerance for debris as cognition ability and cerebral blood flow are not significantly declined. The severity of cerebral infarction varies by debris generated by different treatments.

“Worse than hell”: Complex Neuraxial Lesions Resulting in Tetraplegia and Blindness after Polytrauma - Case presentation

Background. Lesions of the vertebral artery (VA) may develop spontaneously or as a result of severe traumatic cervico-cephalic injuries. Most frequent VA injuries (VAI) result from blunt trauma to the spine or may be due to penetrating lesions. VAI plays a significant role in the broader context of cervical spine trauma by providing insights into the vascular aspects of spinal cord injury (SCI). Upper cervical spine fractures and accompanying subluxation, as well as transverse process fractures extending into the artery bone foramen, are associated with an elevated risk of VAI. Clinical case. A 63-year-old female patient with flaccid C4 AIS-A quadriplegia (global motor score 3/100), vertebral myelopathy, neurogenic bladder, sacral pressure sore, and blindness was transferred from the spinal neurosurgical department. The patient fell from the same level and suffered a mild brain concussion and, apparently, a minor cervical SCI on October 1, 2022. She was asymptomatic, then quickly became tetraplegic, and then blindness added on in a few days. She was operated on on October 7, 2022, for a C6 vertebral body fracture and a C5-6 dislocation. The surgical protocol consisted of anterior spinal cord decompression, dislocation reduction, and mixed anterior fusion with bone grafts and fixation screws. Following the traumatic event, a bilateral posterior cerebral artery (PCA) stroke subsequently produced blindness and partial optic atrophy in both eyes. Serial clinical and imaging examinations confirmed the diagnosis: a subacute bilateral occipital stroke and a chronic lacunar lesion in the right thalamus associated with a severe spinal cord lesion. Anticoagulation has partially improved the neurological outcomes of stroke in the PCA territory. Ethical considerations. The patient's next of kin has given written consent to the case study and to use the radiological images related to the case for academic purposes. The personal identity data was anonymized. The presentation of this clinical case has the approval of the ethics commission of TEHBA (no. 40205/01.09.2023). Discussion. The clinical example is notable for the concurrent development of two severely devastating neurological syndromes, quadriplegia, and blindness, which occurred after an initially minor cervical trauma and progressed gradually over a few days. VA lesions after cervical trauma are considered rare, and the diagnosis is difficult because the vast majority of individuals do not exhibit cerebral neurological symptoms (due to the collateral compensatory blood supply from the circle of Willis). Most of the patients with bilateral or dominant VA occlusions are symptomatic, with rapid (and possibly fatal) ischemic damage to the encephalon, cerebellum, or brainstem. The detection and tracking of evolutionary tendencies required a series of clinical tests, including fundoscopy, and imaging procedures, including native CT, MRI, and MR angiography scans of the brain and spine. Conclusions. Although VAI is a rare complication, in every polytrauma patient with head and neck trauma, VA damage should be suspected. Careful clinical and imaging monitoring through detailed serial imaging procedures must be performed for every person with severe cranio-cervical trauma. The clinical example emphasizes the importance of the interprofessional team's participation in the patient's care.

Angiographic Evaluation of the Feeding Artery in Skull Base Meningioma.

To identify the characteristics of feeding arteries in skull base meningioma including location and prevalence, we evaluated the distributions and types of feeding arteries in skull base meningioma by cerebral angiography and assessed relationships to tumor attachment. We enrolled patients with skull base meningioma who underwent MRI and cerebral digital subtraction angiography (DSA), from September 2015 to October 2022. Subjects comprised 115 patients (32 males, 83 females; mean age, 52.7) with 117 meningiomas, showing tumor attachments around the "cavernous sinus to the upper part of the clivus" (Area 1), "lower part of the clivus to foramen magnum" (Area 2), and "tentorium around the petrous bone" (Area 3). Frequent arteries, such as the dorsal meningeal artery (DMA), the ascending pharyngeal artery (APA), the tentorial artery (TA), and the petrosal branch (PB) of the middle meningeal artery (MMA) were analyzed in terms of their associations with tumor attachment to Areas 1-3. Meningiomas with the DMA as a feeding artery correlated with tumor attachment to Area 1 (p < 0.001). Meningiomas with the APA correlated with tumor attachment to Area 2 (p < 0.001). Meningiomas with the TA correlated with tumor attachment to Area 3 (p < 0.001). The PB correlated with Area 3 (p < 0.05). Our study founded that visualization of these arteries correlated well with specific areas. These arteries were also the main feeders in each type of skull base meningioma.

Iliac endofibrosis in high-performance sports: an interdisciplinary diagnostic challenge

Iliac endofibrosis (IE) is a rare arterial disease in endurance athletes, especially cyclists and triathletes. The diagnosis is considered challenging and the latency from the onset of initial symptoms to diagnosis is often several years. Diagnostic options include determination of the ankle brachial index (ABI) after maximal exercise as a non-invasive procedure, as well as duplex sonography, CT or MRI angiography, and invasive angiography. The aim of this paper is to analyse in more detail this time lag to correct diagnosis from the first description in 1985 to the year 2021, as well as to identify the most important diagnostic tools for practice. Literature research according to PRISMA criteria in PubMed, Web of Science, Cochrane databases, supplemented by a search in Google Scholar up to 10/18/2021. We identified a total of 133 publications that dealt thematically with IE in endurance athletes. In 42 publications (40 case reports and 2 clinical trials), the diagnosis was confirmed intraoperatively, and in 32 (32/42; 74.4%), statements were made about the duration from the onset of the first symptoms to the final diagnosis (mean 45, median 36 months). This latency was constant over the entire observation period from 1985 to 2021, with no trend toward shortening. Twenty-four papers (24/42; 56%) reported detailed results of ABI determination as well as further diagnostic testing. In all cases, the ABI value decreased to less than 0.66 (in 5 case reports, this decrease was measured at rest; in 19 case reports, it occurred after stress), whereas further diagnostic testing by duplex sonography, DSA, MRA, or CTA revealed no abnormal findings in 3 cases (3/24; 12.5%) and showed no more than minor stenosis in 14 cases (14/24; 58.3%). A drop in ABI after exercise is the most reliable method to diagnose iliac endofibrosis. This non-invasive and easy-to-perform examination should be integrated into the performance diagnostics of highly ambitious endurance athletes at risk. This may ideally prevent irreversible vessel wall damage by early diagnosis as well as a reduction of the presumed high number of undetected cases.

Age‐ and Sex‐Related Morphological Changes in Cerebral Blood Vessels: a 7T TOF MRA Study

AbstractBackgroundIn this study we evaluated age‐ and sex‐associated morphological changes of cerebral blood vessels using 7T Time‐of‐flight (TOF) magnetic resonance angiography (MRA).MethodOur study consisted of 25 cognitively normal older adults (20 female, mean age 68.2 years). Whole‐Brain TOF MRA images were collected on a 7T Siemens scanner at the University of Pittsburgh (slice number = 354, voxel size = 0.38*0.38*0.38 mm, 12 mins). An iterative vessel segmentation algorithm, VesselMapper, was used to segment blood vessels on TOF MRA images (Li et al., 2023). For each subject, vessels are further divided into large and small vessels by median split based on vessel diameters. Mean tortuosity of large vessels, small vessels and overall vessels was computed. Linear regression analyses were performed to evaluate the main effects of age and sex, and the age*sex interaction on vessel tortuosity and diameter.ResultAs shown in Figure 1, we found age‐related increase in mean vessel tortuosity (greater age is associated with greater tortuosity, p&lt;0.02). This age‐related difference is driven by small vessels (p = 0.002) rather than large vessels (p = 0.7). We also found that age is positively associated with mean voxel tortuosity (p&lt;0.001, black line in Figure 2). Furthermore, women showed greater age‐related increase in mean arterial tortuosity, compared to men (age*sex interaction p = 0.04, Figure 2).ConclusionOur findings validated that morphological markers of cerebral blood vessels are sensitive to aging. Small vessels in the brain are particularly vulnerable. Further, compared to men, older women are at a higher risk for cerebral small vessel disease, which may contribute to elevated SVD‐related AD risk in women.Limitation: The study has an unbalanced sample (more women than men) and a relatively modest sample size (N = 25). A cross‐sectional instead of longitudinal design was used in this analysis. Future study with a large balanced sample and a longitudinal design are required to confirm our findings.Reference: Li, Jiatai, et al. “VesselMapper ‐ A Robust Vessel Segmentation Algorithm for 3D Images.” Annual Meeting of the Organization for Human Brain Mapping. 2023

Age‐ and Sex‐Related Morphological Changes in Cerebral Blood Vessels: a 7T TOF MRA Study

AbstractBackgroundIn this study we evaluated age‐ and sex‐associated morphological changes of cerebral blood vessels using 7T Time‐of‐flight (TOF) magnetic resonance angiography (MRA).MethodOur study consisted of 25 cognitively normal older adults (20 female, mean age 68.2 years). Whole‐Brain TOF MRA images were collected on a 7T Siemens scanner at the University of Pittsburgh (slice number = 354, voxel size = 0.38*0.38*0.38 mm, 12 mins). An iterative vessel segmentation algorithm, VesselMapper, was used to segment blood vessels on TOF MRA images (Li et al., 2023). For each subject, vessels are further divided into large and small vessels by median split based on vessel diameters. Mean tortuosity of large vessels, small vessels and overall vessels was computed. Linear regression analyses were performed to evaluate the main effects of age and sex, and the age*sex interaction on vessel tortuosity and diameter.ResultAs shown in Figure 1, we found age‐related increase in mean vessel tortuosity (greater age is associated with greater tortuosity, p&lt;0.02). This age‐related difference is driven by small vessels (p = 0.002) rather than large vessels (p = 0.7). We also found that age is positively associated with mean voxel tortuosity (p&lt;0.001, black line in Figure 2). Furthermore, women showed greater age‐related increase in mean arterial tortuosity, compared to men (age*sex interaction p = 0.04, Figure 2).ConclusionOur findings validated that morphological markers of cerebral blood vessels are sensitive to aging. Small vessels in the brain are particularly vulnerable. Further, compared to men, older women are at a higher risk for cerebral small vessel disease, which may contribute to elevated SVD‐related AD risk in women. Limitation: The study has an unbalanced sample (more women than men) and a relatively modest sample size (N = 25). A cross‐sectional instead of longitudinal design was used in this analysis. Future study with a large balanced sample and a longitudinal design are required to confirm our findings. Reference: Li, Jiatai, et al. “VesselMapper ‐ A Robust Vessel Segmentation Algorithm for 3D Images.” Annual Meeting of the Organization for Human Brain Mapping. 2023

Brain MRA 3D Skeleton Extraction Based on Normal Plane Centroid Algorithm

INTRODUCTION: Analysis of magnetic resonance angiography image data is crucial for early detection and prevention of stroke patients. Extracting the 3D Skeleton of cerebral vessels is the focus and difficulty of analysis.&#x0D; OBJECTIVES: The objective is to remove other tissue components from the vascular tissue portion of the image with minimal loss by reading MRA image data and performing processing processes such as grayscale normalization, interpolation, breakpoint detection and repair, and image segmentation to facilitate 3D reconstruction of cerebral blood vessels and the reconstructed vascular tissues make extraction of the Skeleton easier.&#x0D; METHODS: Considering that most of the existing techniques for extracting the 3D vascular Skeleton are corrosion algorithms, machine learning algorithms require high hardware resources, a large number of learning and test cases, and the accuracy needs to be confirmed, an average plane center of mass computation method is proposed, which improves the average plane algorithm by combining the standard plane algorithm and the center of mass algorithm.&#x0D; RESULTS: Intersection points and skeleton breakpoints on the Skeleton are selected as critical points and manually labeled for experimental verification, and the algorithm has higher efficiency and accuracy than other algorithms in directly extracting the 3D Skeleton of blood vessels.&#x0D; CONCLUSION: The method has low hardware requirements, accurate and reliable image data, can be automatically modeled and calculated by Python program, and meets the needs of clinical applications under information technology conditions.

Vascular synthesis based on hemodynamic efficiency principle recapitulates measured cerebral circulation properties in the human brain

Quantifying anatomical and hemodynamical properties of the brain vasculature in vivo is difficult due to limited spatiotemporal resolution neuroimaging, variability between subjects, and bias between acquisition techniques. This work introduces a metabolically inspired vascular synthesis algorithm for creating a digital representation of the cortical blood supply in humans. Spatial organization and segment resistances of a cortical vascular network were generated. Cortical folding and macroscale arterial and venous vessels were reconstructed from anatomical MRI and MR angiography. The remaining network, including ensembles representing the parenchymal capillary bed, were synthesized following a mechanistic principle based on hydrodynamic efficiency of the cortical blood supply. We evaluated the digital model by comparing its simulated values with in vivo healthy human brain measurements of macrovessel blood velocity from phase contrast MRI and capillary bed transit times and bolus arrival times from dynamic susceptibility contrast. We find that measured and simulated values reasonably agree and that relevant neuroimaging observables can be recapitulated in silico. This work provides a basis for describing and testing quantitative aspects of the cerebrovascular circulation that are not directly observable. Future applications of such digital brains include the investigation of the organ-wide effects of simulated vascular and metabolic pathologies.

Central arterial stiffening and intracranial atherosclerosis: the atherosclerosis risk in communities neurocognitive study (ARIC-NCS): Aortic stiffness & intracranial atherosclerosis

ObjectivesPrevious studies suggest an association between central arterial stiffness (CAS) and intracranial atherosclerotic disease (ICAD) among Asian participants with stroke or hypertension; this association has not been evaluated in United States populations. We assessed the cross-sectional association of CAS with ICAD presence and burden in late-life, and differences in association by age, sex, and race. Materials and methodsWe conducted a cross-sectional analysis of 1,285 Atherosclerosis Risk in Communities Study participants [mean age 75 (standard deviation: 5) years, 38 % male, 20 % Black] at Visit 5 (2011-2013). CAS was measured as carotid-femoral pulse wave velocity (cfPWV) using the Omron VP-1000 Plus. ICAD was assessed using high-resolution vessel wall MRI and MR angiography. We evaluated associations of a 1 standard deviation (SD) cfPWV (3.02 m/s) and high vs. non-high cfPWV (≥ 13.57 m/s vs. < 13.57 m/s) with presence of plaques (yes/no) and plaque number (0, 1-2, and >2) using multivariable logistic and ordinal logistic regression models adjusted for covariates. ResultsEach one SD greater cfPWV was associated with higher odds of plaque presence (odds ratio (OR)=1.32, 95 % confidence interval (CI): 1.22, 1.43), and an incrementally higher odds of number of plaques (OR 1-2 vs. 0 plaques = 1.21, 95 % CI: 1.10, 1.33; OR >2 vs. 0 plaques = 1.51, 95 % CI: 1.33,1.71). Results suggested differences by race, with greater magnitude associations among Black participants. ConclusionsCAS was positively associated with ICAD presence and burden; cfPWV may be a useful subclinical vascular measure for identification of individuals who are at high risk for cerebrovascular disease.

Imaging investigation of cervicocranial artery dissection by using high resolution magnetic resonance VWI and MRA: qualitative and quantitative analysis at different stages

BackgroundTo explore the value of magnetic resonance angiography (MRA) and high resolution magnetic resonance vessel wall imaging (HRMR-VWI) in cervicocranial artery dissection (CCAD) for the disease diagnosis, course staging and treatment. On the basis of qualitative evaluation, this study also extract the changes of different stages in vessel wall in different vessel segments to identify imaging indicators for the quantitative evaluation of CCAD.MethodsWe retrospectively enrolled 34 patients with CCAD (38branches) with conventional MRA and HRMR-VWI examinations. Two radiologists independently analyzed imaging features of vessel wall and lumen in the different stages, and the typical sign detection of artery dissection were compared between MRA and HRMR-VWI. Then the parameters of vessel wall was quantitatively evaluated by the post-processing software (Vesselmass, Leiden University Medical Center, Leiden, The Netherlands.ResultsHRMR-VWI revealed typical sign detection of artery dissection in all patients in the acute and subacute stage. Among them, the intimal flap/double lumen sign ditection were more common than the MRA, there was significant difference (P = 0.012). MRA revealed typical sign detection of artery dissection in more than half the patients, and the detection was no significant difference at the chronic stage between MRA and HRMR-VWI (P = 1.000/1.000/0.761). In the acute and subacute stage, the typical sign detection of intramural hematoma and Grade II enhancement revealed by HR-MRI was higher than the observations in the chronic stage (P = 0.000/0.000/0.016), while there was no significant difference by MRA (P = 0.902). The values of wall thickness, relative signal intensity of vessel wall enhancement, relative signal intensity of intramural hematoma (IMH), and percentage of stenosis in CCAD decreased from acute to subacute and then to chronic stages. Each quantitative parameter in patients with CCAD in the early stages (i.e., acute and subacute stages) was significantly different from that in patients with CCAD in the recovered group at chronic stage (P < 0.05). Wall thickness and relative signal intensity of vessel wall enhancement in patients with CCAD in the early stages were not significantly different from those in patients with CCAD in the incompletely recovered group at chronic stage (P > 0.05).ConclusionsAs the only noninvasive imaging technology, HRMR-VWI displays the structure of the vessel wall in vivo, showing not only excellent performance in the early diagnosis of CCAD, but also describing the changes of different stages in the qualitative and quantitative characteristics of vessel wall. It also helps to guide the diseasediagnosis, course staging and treatment of CCAD. Although the diagnostic efficacy of MRA was not as good as HRMR-VWI, it should be the first choice of method for routine examination in evaluating CCAD, especially at the chronic stage of CCAD.

Alagille syndrome and liver: an adult case report

BackgroundAlagille syndrome is a rare autosomal-dominant disorder, representing 10 to 15% of the causes of neonatal cholestasis with no gender predominance. The diagnosis is based on the association of liver, heart, eye, skeleton abnormalities, and characteristic facial appearance.Case presentationAn 18-year-old male patient, with a family history of benign recurrent intrahepatic cholestasis in a brother, was diagnosed at birth with bile duct paucity. He consulted in adulthood for cholestatic jaundice and pruritus. Physical exam found cutaneous jaundice, particular face, skeletal abnormality of fingers, posterior embryotoxon, and splenomegaly. An echocardiogram found cardiovascular abnormalities. The diagnosis of Alagille syndrome was made in front of five major criteria. A liver biopsy revealed a cirrhosis liver. Upper gastrointestinal endoscopy revealed grade II esophageal varices of portal hypertension. Laboratory tests revealed bicytopenia related to hypersplenism, hypoferritinemia, cytolysis with cholestasis, high bilirubin levels, low prothrombin time, hypoalbuminemia, decreased factor V activity, and hypocholesterolemia. The patient had vitamin K supplementation and was put on ursodeoxycholic acid, propranolol for the liver disease, a high protein hypercaloric diet for malnutrition, vitamin D supplementation and bisphosphonate for the osteoporosis, therapeutic abstention with monitoring for the asymptomatic cardiac disease. After a year of treatment, the patient had an overall health status improvement. Abdominal ultrasound found liver nodules. A biliary MRI showed a multinodular liver. The complement by CT hepatic angiography did not show any nodules while the MRI angiography revealed multiple dysplastic nodules. A liver biopsy was performed and found regenerative nodules.ConclusionThe treatment of Alagille syndrome is based on managing the cholestasis and its complications, especially pruritus because it can have a significant impact on quality of life. Due to the complexity of presentation and multi-organ involvement, management of cases with Alagille syndrome should be done by a multidisciplinary team. Liver disease is responsible for morbidity while cardiac disease is a mortality risk factor in this population.