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Cryptogenic stroke refers to a stroke of undetermined etiology. It accounts for approximately one-fifth of ischemic strokes and has a higher prevalence in younger patients. Embolic stroke of undetermined source (ESUS) refers to a subgroup of patients with nonlacunar cryptogenic strokes in whom embolism is the suspected stroke mechanism. Under the classifications of cryptogenic stroke or ESUS, there is wide heterogeneity in possible stroke mechanisms. In the absence of a confirmed stroke etiology, there is no established treatment for secondary prevention of stroke in patients experiencing cryptogenic stroke or ESUS, despite several clinical trials, leaving physicians with a clinical dilemma. Both conventional and advanced MRI techniques are available in clinical practice to identify differentiating features and stroke patterns and to determine or infer the underlying etiologic cause, such as atherosclerotic plaques and cardiogenic or paradoxical embolism due to occult pelvic venous thrombi. The aim of this review is to highlight the diagnostic utility of various MRI techniques in patients with cryptogenic stroke or ESUS. Future trends in technological advancement for promoting the adoption of MRI in such a special clinical application are also discussed.
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AVC Embólico , Imageamento por Ressonância Magnética , Humanos , AVC Embólico/diagnóstico por imagem , AVC Embólico/etiologia , Imageamento por Ressonância Magnética/métodos , AVC Isquêmico/diagnóstico por imagem , AVC Isquêmico/etiologia , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/etiologiaRESUMO
OBJECTIVE: Giant Cell arteritis (GCA) is a large vessel vasculitis, typically involving the aorta and its branches with predilection for the scalp arteries. Intracranial involvement is still part of ongoing research. We assess inflammation of the intracranial arteries on 3D-black-blood magnetic resonance imaging (3D-CS-BB-MRI) in patients with GCA and age-matched controls. METHODS: 105 patients with 3D-CS-BB-MRI of the brain were included in this retrospective dual-center case-control study; 55 with diagnosed GCA and 50 age-matched controls. High-resolution 3D-CS-BB-MRI was performed on a 3 Tesla MR scanner with a post-contrast 3D-compressed-sensing (CS) MR pulse sequence, specifically a T1-weighted sampling perfection, application-optimized contrasts using different flip angle evolution (SPACE) pulse sequence with whole-brain coverage and isotropic resolution of 0.55 mm3. Two neuroradiologists blinded to clinical data independently scored the cerebral arteries qualitatively for inflammation; circumferential vessel wall thickening and contrast enhancement were scored positive for vasculitis. RESULTS: 8 of 55 GCA patients (14.5%) showed inflammation of at least one intracranial artery. The internal carotid artery (ICA) was affected in 6/55 (10.9%), the vertebral artery in 4/55 (7.3%) and the basilar artery and posterior cerebral artery in 1/55 (1.8%). All patients with inflammatory changes reported headaches and none showed any focal neurological deficit. Besides headache and general weakness, there was no significant correlation between inflammation of the intracranial arteries and clinical symptoms. No age-matched control patient showed inflammatory changes of the intracranial arteries. CONCLUSION: High-resolution 3D-CS-BB-MRI revealed inflammatory changes of intracranial arteries in 14.5% of GCA patients with the intradural ICA as the most frequently affected vessel.
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BACKGROUND: Although larger hematoma volume is associated with worse outcome after intracerebral hemorrhage (ICH), the association between perihematomal edema (PHE) volume and outcome remains uncertain, as does the impact of sex on PHE and outcome. Here we aimed to determine whether larger PHE volume is associated with worse outcome and whether PHE volume trajectories differ by sex. METHODS: We conducted a post hoc analysis of the Factor VIIa for Acute Hemorrhagic Stroke Treatment (FAST) trial, which randomized patients with ICH to receive recombinant activated factor VIIa or placebo. Computerized planimetry calculated PHE and ICH volumes on serial computed tomography (CT) scans (at baseline [within 3 h of onset], at 24 h, and at 72 h). Generalized estimating equations examined interactions between sex, CT time points, and FAST treatment arm on PHE and ICH volumes. Mixed and multivariable logistic models examined associations between sex, PHE, and outcomes. RESULTS: A total of 781 patients with supratentorial ICH (mean age 65 years) were included. Compared to women (n = 296), men (n = 485) had similar median ICH (14.9 vs. 13.6 mL, p = 0.053) and PHE volumes (11.1 vs. 10.5 mL, p = 0.56) at baseline but larger ICH and PHE volumes at 24 h (19.0 vs. 14.0 mL, p < 0.001; 22.2 vs. 15.7 mL, p < 0.001) and 72 h (16.0 vs. 11.8 mL, p < 0.001; 28.7 vs. 19.9 mL, p < 0.001). Men had higher absolute early PHE expansion (p < 0.001) and more hematoma expansion (growth ≥ 33% or 6 mL at 24 h, 33% vs. 22%, p < 0.001). An interaction between sex and CT time points on PHE volume (p < 0.001), but not on ICH volume, confirmed a steeper PHE trajectory in men. PHE expansion (per 5 mL, odds radio 1.19, 95% confidence interval 1.10-1.28), but not sex, was associated with poor outcome. CONCLUSIONS: Early PHE expansion and trajectory in men were significantly higher. PHE expansion was associated with poor outcomes independent of sex. Mechanisms leading to sex differences in PHE trajectories merit further investigation.
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Edema Encefálico , Hemorragia Cerebral , Fator VIIa , Humanos , Masculino , Feminino , Idoso , Edema Encefálico/diagnóstico por imagem , Edema Encefálico/etiologia , Pessoa de Meia-Idade , Hemorragia Cerebral/diagnóstico por imagem , Fator VIIa/uso terapêutico , Hematoma/diagnóstico por imagem , Caracteres Sexuais , Tomografia Computadorizada por Raios X , Fatores Sexuais , Proteínas Recombinantes/uso terapêutico , Avaliação de Resultados em Cuidados de SaúdeRESUMO
OBJECTIVES: Endovascular thrombectomy (EVT) dramatically improves clinical outcomes, but the reduction in final infarct volume only accounts for 10-15 % of the treatment benefit. We aimed to develop a novel MRI-ADC-based metric that quantify the degree of tissue injury to test the hypothesis that it outperforms infarct volume in predicting long-term outcome. MATERIALS AND METHODS: A single-center cohort consisted of consecutive acute stroke patients with anterior circulation large vessel occlusion, successful recanalization via EVT (mTICI ≥2b), and MRI of the brain between 12 h and 7 days post-EVT. Imaging was processed via RAPID software. Final infarct volume was based on the traditional ADC <620 threshold. Logistic regression quantified the association of lesion volumes and good outcome (90-day modified Rankin Scale ≤2) at a range of lower ADC thresholds (<570, <520, and <470). Infarct density was calculated as the percentage of the final infarct volume below the ADC threshold with the greatest effect size. Univariate and multivariate logistic regression quantified the association between imaging/clinical metrics and functional outcome. RESULTS: 120 patients underwent MRI after successful EVT. Lesion volume based on the ADC threshold <470 had the strongest association with good outcome (OR: 0.81 per 10 mL; 95 % CI: 0.66-0.99). In a multivariate model, infarct density (<470/<620 * 100) was independently associated with good outcome (aOR 0.68 per 10 %; 95 % CI: 0.49-0.95), but final infarct volume was not (aOR 0.98 per 10 mL; 95 % CI: 0.85-1.14). CONCLUSIONS: Infarct density after EVT is more strongly associated with long-term clinical outcome than infarct volume.
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OBJECTIVES: We conducted a systematic review and individual participant data meta-analysis of publications reporting the ophthalmologic presentation, clinical exam, and orbital MRI findings in patients with giant cell arteritis and ocular manifestations. METHODS: PubMed and Cochrane databases were searched up to January 16, 2022. Publications reporting patient-level data on patients with ophthalmologic symptoms, imaged with orbital MRI, and diagnosed with biopsy-proven giant cell arteritis were included. Demographics, clinical symptoms, exam, lab, imaging, and outcomes data were extracted. The methodological quality and completeness of reporting of case reports were assessed. RESULTS: Thirty-two studies were included comprising 51 patients (females = 24; median age, 76 years). Vision loss (78%) and headache (45%) were commonly reported visual and cranial symptoms. Ophthalmologic presentation was unilateral (41%) or bilateral (59%). Fundus examination most commonly showed disc edema (64%) and pallor (49%). Average visual acuity was very poor (2.28 logMAR ± 2.18). Diagnoses included anterior (61%) and posterior (16%) ischemic optic neuropathy, central retinal artery occlusion (8%), and orbital infarction syndrome (2%). On MRI, enhancement of the optic nerve sheath (53%), intraconal fat (25%), and optic nerve/chiasm (14%) was most prevalent. Among patients with monocular visual symptoms, 38% showed pathologic enhancement in the asymptomatic orbit. Six of seven cases reported imaging resolution after treatment on follow-up MRIs. CONCLUSIONS: Vision loss, pallid disc edema, and optic nerve sheath enhancement are the most common clinical, fundoscopic, and imaging findings reported in patients diagnosed with giant cell arteritis with ocular manifestations, respectively. MRI may detect subclinical inflammation and ischemia in the asymptomatic eye and may be an adjunct diagnostic tool. CLINICAL RELEVANCE STATEMENT: Brain and orbital MRIs may have diagnostic and prognostic roles in patients with suspected giant cell arteritis who present with ophthalmic symptoms.
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Arterite de Células Gigantes , Neuropatia Óptica Isquêmica , Feminino , Humanos , Idoso , Arterite de Células Gigantes/complicações , Arterite de Células Gigantes/diagnóstico por imagem , Transtornos da Visão , Imageamento por Ressonância Magnética/métodos , Neuropatia Óptica Isquêmica/diagnóstico , Neuropatia Óptica Isquêmica/etiologia , Edema/complicaçõesRESUMO
OBJECTIVE: Blindness is a feared complication of giant cell arteritis (GCA). However, the spectrum of pathologic orbital imaging findings on magnetic resonance imaging (MRI) in GCA is not well understood. In this study, we assess inflammatory changes of intraorbital structures on black blood MRI (BB-MRI) in patients with GCA compared to age-matched controls. METHODS: In this multicenter case-control study, 106 subjects underwent BB-MRI. Fifty-six patients with clinically or histologically diagnosed GCA and 50 age-matched controls without clinical or laboratory evidence of vasculitis were included. All individuals were imaged on a 3-T MR scanner with a post-contrast compressed-sensing (CS) T1-weighted sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) BB-MRI sequence. Imaging results were correlated with available clinical symptoms. RESULTS: Eighteen of 56 GCA patients (32%) showed inflammatory changes of at least one of the intraorbital structures. The most common finding was enhancement of at least one of the optic nerve sheaths (N = 13, 72%). Vessel wall enhancement of the ophthalmic artery was unilateral in 8 and bilateral in 3 patients. Enhancement of the optic nerve was observed in one patient. There was no significant correlation between imaging features of inflammation and clinically reported orbital symptoms (p = 0.10). None of the age-matched control patients showed any inflammatory changes of intraorbital structures. CONCLUSIONS: BB-MRI revealed inflammatory findings in the orbits in up to 32% of patients with GCA. Optic nerve sheath enhancement was the most common intraorbital inflammatory change on BB-MRI. MRI findings were independent of clinically reported orbital symptoms. KEY POINTS: ⢠Up to 32% of GCA patients shows signs of inflammation of intraorbital structures on BB-MRI. ⢠Enhancement of the optic nerve sheath is the most common intraorbital finding in GCA patients on BB-MRI. ⢠Features of inflammation of intraorbital structures are independent of clinically reported symptoms.
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Arterite de Células Gigantes , Humanos , Arterite de Células Gigantes/complicações , Arterite de Células Gigantes/diagnóstico por imagem , Estudos de Casos e Controles , Angiografia por Ressonância Magnética , Imageamento por Ressonância Magnética/métodos , Inflamação/patologia , Artérias Temporais/patologiaRESUMO
PURPOSE: Beyond vessel wall enhancement, little is understood about vessel wall MR imaging (VW-MRI) features of vasculitis affecting the central nervous system (CNS). We reviewed vessel wall MR imaging patterns of inflammatory versus infectious vasculitis and also compared imaging patterns for intracranial versus extracranial arteries of the head and neck. METHODS: Studies reporting vasculitis of the CNS/head and neck and included MR imaging descriptions of vessel wall features were identified by searching PubMed, Scopus, Cochrane, Web of Science, and EMBASE up to June 10, 2020. From 6065 publications, 115 met the inclusion criteria. Data on study characteristics, vasculitis type, MR details, and VW-MRI descriptions were extracted. RESULTS: Studies used VW-MRI for inflammatory (64%), infectious (17%), or both inflammatory and infectious vasculitides (19%). Vasculitis affecting intracranial versus extracranial arteries were reported in 58% and 39% of studies, respectively. Commonly reported VW-MRI features were vessel wall enhancement (89%), thickening (72%), edema (10%), and perivascular enhancement (16%). Inflammatory vasculitides affecting the intracranial arteries were less frequently reported to have vessel wall thickening (p = 0.006) and perivascular enhancement (p = 0.001) than extracranial arteries. Varicella zoster/herpes simplex vasculitis (VZV/HSV, 45%) and primary angiitis of the CNS (PACNS, 22%) were the most commonly reported CNS infectious and inflammatory vasculitides, respectively. Patients with VZV/HSV vasculitis more frequently showed decreased or resolution of vessel wall enhancement after therapy compared to PACNS (89% versus 59%). CONCLUSIONS: To establish imaging biomarkers of vessel wall inflammation in the CNS, VW-MRI features of vasculitis accounting for disease mechanism and anatomy should be better understood.
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Angiografia por Ressonância Magnética , Vasculite do Sistema Nervoso Central , Humanos , Imageamento por Ressonância Magnética , Vasculite do Sistema Nervoso Central/diagnóstico por imagemRESUMO
BACKGROUND AND PURPOSE: Intracranial atherosclerotic disease is a common cause of stroke worldwide. Intracranial vessel wall magnetic resonance imaging may be able to identify imaging biomarkers of symptomatic plaque. We performed a meta-analysis to evaluate the strength of association of imaging features of symptomatic plaque leading to downstream ischemic events. Effects on the strength of association were also assessed accounting for possible sources of bias and variability related to study design and magnetic resonance parameters. METHODS: PubMed, Scopus, Web of Science, EMBASE, and Cochrane databases were searched up to October 2019. Two independent reviewers extracted data on study design, vessel wall magnetic resonance imaging techniques, and imaging end points. Per-lesion odds ratios (OR) were calculated and pooled using a bivariate random-effects model. Subgroup analyses, sensitivity analysis, and evaluation of publication bias were also performed. RESULTS: Twenty-one articles met inclusion criteria (1750 lesions; 1542 subjects). Plaque enhancement (OR, 7.42 [95% CI, 3.35-16.43]), positive remodeling (OR, 5.60 [95% CI, 2.23-14.03]), T1 hyperintensity (OR, 2.05 [95% CI, 1.27-3.32]), and surface irregularity (OR, 4.50 [95% CI, 1.39-8.57]) were significantly associated with downstream ischemic events. T2 signal intensity was not significant (P=0.59). Plaque enhancement was significantly associated with downstream ischemic events in all subgroup analyses and showed stronger associations when measured in retrospectively designed studies (P=0.02), by a radiologist as a rater (P<0.001), and on lower vessel wall magnetic resonance imaging spatial resolution sequences (P=0.02). CONCLUSIONS: Plaque enhancement, positive remodeling, T1 hyperintensity, and surface irregularity emerged as strong imaging biomarkers of symptomatic plaque in patients with ischemic events. Plaque enhancement remained significant accounting for sources of bias and variability in both study design and instrument. Future studies evaluating plaque enhancement as a predictive marker for stroke recurrence with larger sample sizes would be valuable.
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Vasos Sanguíneos/diagnóstico por imagem , Arteriosclerose Intracraniana/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Biomarcadores , Humanos , Placa Aterosclerótica/diagnóstico por imagem , Sensibilidade e EspecificidadeRESUMO
PURPOSE: The vessel wall MR imaging (VWI) literature was systematically reviewed to assess the criteria and measurement methods of VWI-related imaging endpoints for symptomatic intracranial plaque in patients with ischemic events. METHODS: PubMed, Scopus, Web of Science, EMBASE, and Cochrane databases were searched up to October 2019. Two independent reviewers extracted data from 47 studies. A modified Guideline for Reporting Reliability and Agreement Studies was used to assess completeness of reporting. RESULTS: The specific VWI-pulse sequence used to identify plaque was reported in 51% of studies. A VWI-based criterion to define plaque was reported in 38% of studies. A definition for culprit plaque was reported in 40% of studies. Frequently scored qualitative imaging endpoints were plaque quadrant (21%) and enhancement (21%). Frequently measured quantitative imaging endpoints were stenosis (19%), lumen area (15%), and remodeling index (14%). Reproducibility for all endpoints ranged from good to excellent (range: ICCT1 hyperintensity = 0.451 to ICCstenosis = 0.983). However, rater specialty and years of experience varied among studies. CONCLUSIONS: Investigators are using different criteria to identify and measure VWI-imaging endpoints for culprit intracranial plaque. Early awareness of these differences to address methods of acquisition and measurement will help focus research resources and efforts in technique optimization and measurement reproducibility. Consensual definitions to detect plaque will be important to develop automatic lesion detection tools particularly in the era of radiomics.
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Arteriosclerose Intracraniana , Placa Aterosclerótica , Humanos , Arteriosclerose Intracraniana/diagnóstico por imagem , Angiografia por Ressonância Magnética , Imageamento por Ressonância Magnética , Reprodutibilidade dos TestesRESUMO
Diffusion magnetic resonance (MR) tractography represents a novel opportunity to investigate conserved and deviant developmental programs between humans and other species such as mice. To that end, we acquired high angular resolution diffusion MR scans of mice [embryonic day (E) 10.5 to postnatal week 4] and human brains [gestational week (GW) 17-30] at successive stages of fetal development to investigate potential evolutionary changes in radial organization and emerging pathways between humans and mice. We compare radial glial development as well as commissural development (e.g., corpus callosum), primarily because our findings can be integrated with previous work. We also compare corpus callosal growth trajectories across primates (i.e., humans and rhesus macaques) and rodents (i.e., mice). One major finding is that the developing cortex of humans is predominated by pathways likely associated with a radial glial organization at GW 17-20, which is not as evident in age-matched mice (E 16.5, 17.5). Another finding is that, early in development, the corpus callosum follows a similar developmental timetable in primates (i.e., macaques and humans) as in mice. However, the corpus callosum grows for an extended period of time in primates compared with rodents. Taken together, these findings highlight deviant developmental programs underlying the emergence of cortical pathways in the human brain.
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Córtex Cerebral/fisiologia , Corpo Caloso/fisiologia , Desenvolvimento Fetal/fisiologia , Vias Neurais/fisiologia , Animais , Córtex Cerebral/embriologia , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Tensor de Difusão/métodos , Idade Gestacional , Humanos , Macaca mulatta , Camundongos , Vias Neurais/embriologiaRESUMO
OBJECTIVES: Luminal-based imaging have identified different risk factors for extracranial and intracranial atherosclerosis (ICAS), but these techniques are known to underestimate the true extent of the disease. High-resolution (HR) vessel wall imaging (VWI) has recently gained recognition as a valuable tool in the assessment of ICAS. The aim of this study is to determine the association between cardiovascular risk factors and specific intracranial vessel segment involvement using HR-VWI. MATERIALS AND METHODS: From January 2017 to January 2020, consecutive patients ≥ 18 years-old undergoing HR-VWI of the brain were identified. Patients with history of primary or secondary vasculitis, reversible cerebral vasoconstriction syndrome, or moya-moya were excluded. The presence of vessel wall thickening and enhancement were assessed in the perpendicular plane for each vessel segment by two neuroradiologists. Univariate and multivariate analyses were performed to assess associations between imaging findings and cardiovascular risk factors. Interrater reliability was calculated. RESULTS: Seventy-one patients (39 men; mean age: 55.9 years) were included. Vessel wall enhancement was seen in 39/71 (55%). A total number of 105 vessel segments demonstrated abnormal enhancement and 79/105 (75%) had an eccentric pattern. Eccentric vessel wall enhancement was independently associated with age >65 years-old in the ICA (OR 9.0, CI 2.1 - 38.2, p < 0.01) and proximal MCA (OR 4.0, CI 1.2 - 13.2, p = 0.02), and with hyperlipidemia in the posterior circulation (OR 44.0, CI2.9-661.0, p<0.01). CONCLUSION: There is a significant association between eccentric vessel wall enhancement of the ICA and proximal MCA in patients with age > 65; and of the proximal posterior circulation (basilar - PCA1) with hyperlipidemia.
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Angiografia Cerebral , Artérias Cerebrais/diagnóstico por imagem , Arteriosclerose Intracraniana/diagnóstico por imagem , Angiografia por Ressonância Magnética , Adulto , Idoso , Bases de Dados Factuais , Feminino , Fatores de Risco de Doenças Cardíacas , Humanos , Arteriosclerose Intracraniana/etiologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Medição de RiscoRESUMO
BACKGROUND: Quantitative susceptibility mapping (QSM) uses prior information to reconstruct maps, but prior information may not show pathology and introduce inconsistencies with susceptibility maps, degrade image quality and inadvertently smoothing image features. PURPOSE: To develop a local field data-driven QSM reconstruction that does not depend on spatial edge prior information. STUDY TYPE: Retrospective. SUBJECTS, ANIMAL MODELS: A dataset from 2016 ISMRM QSM Challenge, 11 patients with glioblastoma, a patient with microbleeds and porcine heart. SEQUENCE/FIELD STRENGTH: 3D gradient echo sequence on 3T and 7T scanners. ASSESSMENT: Accuracy was compared to Calculation of Susceptibility through Multiple Orientation Sampling (COSMOS), and several published techniques using region of interest (ROI) measurements, root-mean-squared error (RMSE), structural similarity index metric (SSIM), and high-frequency error norm (HFEN). Numerical ranking and semiquantitative image grading was performed by three expert observers to assess overall image quality (IQ) and image sharpness (IS). STATISTICAL TESTS: Bland-Altman, Friedman test, and Conover multiple comparisons. RESULTS: Loss adaptive dipole inversion (LADI) (ß = 0.82, R2 = 0.96), morphology-enabled dipole inversion (MEDI) (ß = 0.91, R2 = 0.97), and fast nonlinear susceptibility inversion (FANSI) (ß = 0.81, R2 = 0.98) had excellent correlation with COSMOS and no bias was detected (bias = 0.006 ± 0.014, P < 0.05). In glioblastoma patients, LADI showed consistently better performance (IQGrade = 2.6 ± 0.4, ISGrade = 2.6 ± 0.3, IQRank = 3.5 ± 0.4, ISRank = 3.9 ± 0.2) compared with MEDI (IQGrade = 2.1 ± 0.3, ISGrade = 2 ± 0.5, IQRank = 2.4 ± 0.5, ISRank = 2.8 ± 0.2) and FANSI (IQGrade = 2.2 ± 0.5, ISGrade = 2 ± 0.4, IQRank = 2.8 ± 0.3, ISRank = 2.1 ± 0.2). Dark artifact visible near the infarcted region in MEDI (InfMEDI = -0.27 ± 0.06 ppm) was better mitigated by FANSI (InfFANSI-TGV = -0.17 ± 0.05 ppm) and LADI (InfLADI = -0.18 ± 0.05 ppm). CONCLUSION: For neuroimaging applications, LADI preserved image sharpness and fine features in glioblastoma and microbleed patients. LADI performed better at mitigating artifacts in cardiac QSM. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY STAGE: 1 J. Magn. Reson. Imaging 2020;52:823-835.
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Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Algoritmos , Animais , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Humanos , Estudos Retrospectivos , SuínosRESUMO
Prenatal detection of abnormal white matter tracts might serve as a structural marker for altered neurodevelopment. As a result of many technical and patient-related challenges, the accuracy of prenatal tractography remains unknown. We hypothesized that characteristics of prenatal tractography of the corpus callosum and corticospinal tracts derived from fetal diffusion tensor imaging (DTI) data are accurate and predictive of the integrity of these tracts postnatally. We compared callosal and corticospinal tracts of 12 subjects with paired prenatal (age: 23-35 gestational weeks) and postnatal (age: 1 day to 2 years) DTI examinations (b values of 0 s/mm2 and 700 s/mm2, 16 gradient encoding directions) using deterministic tractography. Evaluation for the presence of callosal segments and corticospinal tracts showed moderate degrees of accuracy (67-75%) for the four segments of the corpus callosum and moderate to high degrees of accuracy (75-92%) for the corticospinal tracts. Positive predictive values for segments of the corpus callosum ranged from 50% to 100% and for the corticospinal tracts, 89% to 100%. Negative predictive values for segments of the corpus callosum ranged from 25% to 80% and for the corticospinal tracts, 33% to 50%. The results suggest that when the tracts are not well characterized on the fetal MR, predictions about the postnatal tracts are difficult to make. However, accounting for brain maturation, prenatal visualization of the main projection and commissural tracts can be clinically used as an important predictive tool in the context of image interpretation for the assessment of fetal brain malformations.
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Agenesia do Corpo Caloso/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Tratos Piramidais/anormalidades , Substância Branca/anormalidades , Feminino , Seguimentos , Idade Gestacional , Humanos , Lactente , Masculino , Valor Preditivo dos Testes , Gravidez , Estudos Retrospectivos , Sensibilidade e EspecificidadeAssuntos
Artéria Basilar/diagnóstico por imagem , Infartos do Tronco Encefálico/diagnóstico por imagem , Placa Aterosclerótica/diagnóstico por imagem , Ponte/irrigação sanguínea , Doenças do Nervo Abducente/fisiopatologia , Infartos do Tronco Encefálico/fisiopatologia , Diplopia/fisiopatologia , Disartria/fisiopatologia , Humanos , Hipestesia/fisiopatologia , Angiografia por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Paresia/fisiopatologia , Ponte/diagnóstico por imagemRESUMO
Little is known about the emergence of structural asymmetry of white matter tracts during early brain development. We examined whether and when asymmetry in diffusion parameters of limbic and association white matter pathways emerged in humans in 23 brains ranging from 15 gestational weeks (GW) up to 3 years of age (11 ex vivo and 12 in vivo cases) using high-angular resolution diffusion imaging tractography. Age-related development of laterality was not observed in a limbic connectional pathway (cingulum bundle or fornix). Among the studied cortico-cortical association pathways (inferior longitudinal fasciculus [ILF], inferior fronto-occipital fasciculus, and arcuate fasciculus), only the ILF showed development of age-related laterality emerging as early as the second trimester. Comparisons of ages older and younger than 40 GW revealed a leftward asymmetry in the cingulum bundle volume and a rightward asymmetry in apparent diffusion coefficient and leftward asymmetry in fractional anisotropy in the ILF in ages older than 40 GW. These results suggest that morphometric asymmetry in cortical areas precedes the emergence of white matter pathway asymmetry. Future correlative studies will investigate whether such asymmetry is anatomically/genetically driven or associated with functional stimulation.
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Encéfalo , Lateralidade Funcional/fisiologia , Substância Branca , Fatores Etários , Encéfalo/anatomia & histologia , Encéfalo/embriologia , Encéfalo/crescimento & desenvolvimento , Pré-Escolar , Imagem de Difusão por Ressonância Magnética , Feminino , Feto/anatomia & histologia , Idade Gestacional , Humanos , Processamento de Imagem Assistida por Computador , Lactente , Recém-Nascido , Masculino , Substância Branca/anatomia & histologia , Substância Branca/embriologia , Substância Branca/crescimento & desenvolvimentoRESUMO
Tendinous and subcutaneous xanthomas are most commonly associated with primary hyperlipidemia. Xanthomatosis caused by cholesterol deposition can be a high risk marker for cardiovascular disease related to premature atherosclerosis; thus, early recognition of this diagnosis may reduce mortality and morbidity. Achilles tendon involvement is most common, followed by the extensor tendons of the hand and elbow. We present an exceptional case of tendinous and tuberous xanthomas, with intraoperative and histologic correlation, in a 34-year-old female manifesting with xanthomatous deposits of nearly all ankle tendons, plantar aponeurosis, extensor tendons of the hands, and various locations within the integumentum. To the authors' knowledge, only four studies to date have focused specifically on imaging findings of multifocal xanthomas. Thus, the radiographic and MR imaging descriptions of xanthomas in this report further add to the existing literature by helping to identify imaging characteristics of this multifocal systemic disease. The diagnosis of this condition should alert the physician to the presence of a dyslipidemia that can be treated with dietary modifications and/or drug therapy.