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1.
Magn Reson Med ; 87(1): 102-119, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34398991

RESUMO

PURPOSE: To address head motion in brain MRI with a novel motion-resolved imaging framework, with application to motion-robust quantitative multiparametric mapping. METHODS: MR multitasking conceptualizes the underlying multiparametric image in the presence of motion as a multidimensional low-rank tensor. By incorporating a motion-state dimension into the parameter dimensions and introducing unsupervised motion-state binning and outlier motion reweighting mechanisms, the brain motion can be readily resolved for motion-robust quantitative imaging. A numerical motion phantom was used to simulate different discrete and periodic motion patterns under various translational and rotational scenarios, as well as investigate the sensitivity to exceptionally small and large displacements. In vivo brain MRI was performed to also evaluate different real discrete and periodic motion patterns. The effectiveness of motion-resolved imaging for simultaneous T1 /T2 /T1 ρ mapping in the brain was investigated. RESULTS: For all 14 simulation scenarios of small, intermediate, and large motion displacements, the motion-resolved approach produced T1 /T2 /T1 ρ maps with less absolute difference errors against the ground truth, lower RMSE, and higher structural similarity index measure of T1 /T2 /T1ρ measurements compared to motion removal, and no motion handling. For in vivo experiments, the motion-resolved approach produced T1 /T2 /T1 ρ maps with the best image quality free from motion artifacts under random discrete motion, tremor, periodic shaking, and nodding patterns compared to motion removal and no motion handling. The proposed method also yielded T1 /T2 /T1 ρ measurement distributions closest to the motion-free reference, with minimal measurement bias and variance. CONCLUSION: Motion-resolved quantitative brain imaging is achieved with multitasking, which is generalizable to various head motion patterns without explicit need for registration-based motion correction.

2.
Magn Reson Med ; 87(1): 120-137, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34418152

RESUMO

PURPOSE: To develop a 3D multitasking multi-echo (MT-ME) technique for the comprehensive characterization of liver tissues with 5-min free-breathing acquisition; whole-liver coverage; a spatial resolution of 1.5 × 1.5 × 6 mm3 ; and simultaneous quantification of T1 , water-specific T1 (T1w ), proton density fat fraction (PDFF), and R 2 ∗ . METHODS: Six-echo bipolar spoiled gradient echo readouts following inversion recovery preparation was performed to generate T1 , water/fat, and R 2 ∗ contrast. MR multitasking was used to reconstruct the MT-ME images with 3 spatial dimensions: 1 T1 recovery dimension, 1 multi-echo dimension, and 1 respiratory dimension. A basis function-based approach was developed for T1w quantification, followed by the estimation of R 2 ∗ and T1 -corrected PDFF. The intrasession repeatability and agreement against references of MT-ME measurements were tested on a phantom and 15 clinically healthy subjects. In addition, 4 patients with confirmed liver diseases were recruited, and the agreement between MT-ME measurements and references was assessed. RESULTS: MT-ME produced high-quality, coregistered T1 , T1w , PDFF, and R 2 ∗ maps with good intrasession repeatability and substantial agreement with references on phantom and human studies. The intra-class coefficients of T1 , T1w , PDFF, and R 2 ∗ from the repeat MT-ME measurements on clinically healthy subjects were 0.989, 0.990, 0.999, and 0.988, respectively. The intra-class coefficients of T1 , PDFF, and R 2 ∗ between the MT-ME and reference measurements were 0.924, 0.987, and 0.975 in healthy subjects and 0.980, 0.999, and 0.998 in patients. The T1w was independent to PDFF (R = -0.029, P = .904). CONCLUSION: The proposed MT-ME technique quantifies T1 , T1w , PDFF, and R 2 ∗ simultaneously and is clinically promising for the comprehensive characterization of liver tissue properties.

3.
Magn Reson Med ; 87(1): 488-495, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34374468

RESUMO

PURPOSE: To develop a deep-learning-based method to quantify multiple parameters in the brain from conventional contrast-weighted images. METHODS: Eighteen subjects were imaged using an MR Multitasking sequence to generate reference T1 and T2 maps in the brain. Conventional contrast-weighted images consisting of T1 MPRAGE, T1 GRE, and T2 FLAIR were acquired as input images. A U-Net-based neural network was trained to estimate T1 and T2 maps simultaneously from the contrast-weighted images. Six-fold cross-validation was performed to compare the network outputs with the MR Multitasking references. RESULTS: The deep-learning T1 /T2 maps were comparable with the references, and brain tissue structures and image contrasts were well preserved. A peak signal-to-noise ratio >32 dB and a structural similarity index >0.97 were achieved for both parameter maps. Calculated on brain parenchyma (excluding CSF), the mean absolute errors (and mean percentage errors) for T1 and T2 maps were 52.7 ms (5.1%) and 5.4 ms (7.1%), respectively. ROI measurements on four tissue compartments (cortical gray matter, white matter, putamen, and thalamus) showed that T1 and T2 values provided by the network outputs were in agreement with the MR Multitasking reference maps. The mean differences were smaller than ± 1%, and limits of agreement were within ± 5% for T1 and within ± 10% for T2 after taking the mean differences into account. CONCLUSION: A deep-learning-based technique was developed to estimate T1 and T2 maps from conventional contrast-weighted images in the brain, enabling simultaneous qualitative and quantitative MRI without modifying clinical protocols.

4.
Magn Reson Med ; 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34708438

RESUMO

PURPOSE: To develop a new technique that enables simultaneous quantification of whole-brain T1 , T2 , T 2 ∗ , as well as susceptibility and synthesis of six contrast-weighted images in a single 9.1-minute scan. METHODS: The technique uses hybrid T2 -prepared inversion-recovery pulse modules and multi-echo gradient-echo readouts to collect k-space data with various T1, T2, and T 2 ∗ weightings. The underlying image is represented as a six-dimensional low-rank tensor consisting of three spatial dimensions and three temporal dimensions corresponding to T1 recovery, T2 decay, and multi-echo behaviors, respectively. Multiparametric maps were fitted from reconstructed image series. The proposed method was validated on phantoms and healthy volunteers, by comparing quantitative measurements against corresponding reference methods. The feasibility of generating six contrast-weighted images was also examined. RESULTS: High quality, co-registered T1 , T2 , and T 2 ∗ susceptibility maps were generated that closely resembled the reference maps. Phantom measurements showed substantial consistency (R2 > 0.98) with the reference measurements. Despite the significant differences of T1 (p < .001), T2 (p = .002), and T 2 ∗ (p = 0.008) between our method and the references for in vivo studies, excellent agreement was achieved with all intraclass correlation coefficients greater than 0.75. No significant difference was found for susceptibility (p = .900). The framework is also capable of synthesizing six contrast-weighted images. CONCLUSION: The MR Multitasking-based 3D brain mapping of T1 , T2 , T 2 ∗ , and susceptibility agrees well with the reference and is a promising technique for multicontrast and quantitative imaging.

5.
Sci Rep ; 11(1): 19195, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34584114

RESUMO

Low back pain (LBP) is often a result of a degenerative process in the intervertebral disc. The precise origin of discogenic pain is diagnosed by the invasive procedure of provocative discography (PD). Previously, we developed quantitative chemical exchange saturation transfer (qCEST) magnetic resonance imaging (MRI) to detect pH as a biomarker for discogenic pain. Based on these findings we initiated a clinical study with the goal to evaluate the correlation between qCEST values and PD results in LBP patients. Twenty five volunteers with chronic low back pain were subjected to T2-weighted (T2w) and qCEST MRI scans followed by PD. A total of 72 discs were analyzed. The average qCEST signal value of painful discs was significantly higher than non-painful discs (p = 0.012). The ratio between qCEST and normalized T2w was found to be significantly higher in painful discs compared to non-painful discs (p = 0.0022). A receiver operating characteristics (ROC) analysis indicated that qCEST/T2w ratio could be used to differentiate between painful and non-painful discs with 78% sensitivity and 81% specificity. The results of the study suggest that qCEST could be used for the diagnosis of discogenic pain, in conjunction with the commonly used T2w scan.

6.
Magn Reson Med ; 86(6): 3182-3191, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34309072

RESUMO

PURPOSE: To develop a single-scan method for B 1 + -corrected T1 mapping and apply it for free-breathing (FB) cardiac MR multitasking without electrocardiogram (ECG) triggering. METHODS: One dual flip-angle (2FA) inversion recovery (IR)-FLASH scan provides two observations of T 1 ∗ (apparent T1 ) corresponding to two distinct combinations of the nominal FA α and B 1 + . Spatiotemporally coregistered T1 and B 1 + spin history maps are obtained by fitting the 2FA signal model. T1 estimate accuracy and repeatability for single flip-angle (1FA) and 2FA IR-FLASH sequence MR multitasking were evaluated at 3T. A T1 phantom was first imaged on the scanner table, then on two human subjects' thoraxes in both breath-hold (BH) and FB conditions. IR-turbo spin echo (IR-TSE) static phantom T1 measurements served as reference. In 10 healthy subjects, myocardial T1 was evaluated with ECG-free, FB multitasking sequences alongside ECG-triggered BH MOLLI. RESULTS: For phantom-on-table T1 estimates, 2FA agreed better with IR-TSE (intraclass correlation coefficient [ICC] = 0.996, mean error ± SD = -1.6% ± 1.9%) than did 1FA (ICC = 0.922; mean error ± SD = -4.3% ± 12%). For phantom-on-thorax, 2FA was more repeatable and robust to respiration than 1FA (coefficient of variation [CoV] = 1.2% 2FA, = 11.3% 1FA). In vivo, in intrasession T1 repeatability, 2FA (septal CoV = 2.4%, six-segment CoV = 4.4%) outperformed 1FA (septal CoV = 3.1%, six-segment CoV = 5.5%). In six-segment T1 homogeneity, 2FA (CoV = 7.9%) also outperformed 1FA (CoV = 11.1%). CONCLUSION: The 2FA IR-FLASH improves T1 estimate accuracy and repeatability over 1FA IR-FLASH, and enables single-scan B 1 + -corrected T1 mapping without BHs or ECG when used with MR multitasking.


Assuntos
Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Humanos , Espectroscopia de Ressonância Magnética , Miocárdio , Imagens de Fantasmas , Reprodutibilidade dos Testes
7.
J Magn Reson Imaging ; 2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34327763

RESUMO

BACKGROUND: Chemical exchange saturation transfer (CEST) is an emerging metabolic MRI technique to map creatine distribution in the myocardium. PURPOSE: To investigate the feasibility of using a contrast-free CEST technique to evaluate cardiac involvement in amyloid light-chain (AL) amyloidosis. STUDY TYPE: Prospective. POPULATION: Forty patients with biopsy-proven AL amyloidosis (age 57.6 ± 9.1 years, 31 males) and 20 healthy controls (age 42.8 ± 13.8 years, 13 males). FIELD STRENGTH/SEQUENCE: A 3.0 T, CEST imaging using a single-shot FLASH sequence, T1 mapping with a modified Look-Locker inversion recovery sequence and late gadolinium enhancement (LGE) imaging with a phase-sensitive inversion recovery gradient echo sequence. ASSESSMENT: The average CEST was calculated in the basal short-axis slice of the entire left ventricle and septum. LGE was assessed subjectively (none/patchy/global) and extracellular volume (ECV), CEST and T1 maps generated. STATISTICAL TESTS: Comparison between patient groups and healthy controls was performed by one-way analysis of variance with post hoc Bonferroni correction. Correlation was assessed using the Pearson's r correlation or Spearman ρ correlation. Statistical significance was defined as P < 0.05. RESULTS: Global (0.09 ± 0.03 vs. 0.11 ± 0.02) and septal (0.09 ± 0.03 vs. 0.11 ± 0.03) basal short-axis CEST was significantly decreased in patients with AL amyloidosis compared to the controls. Global CEST correlated significantly with Mayo stage (ρ = -0.508), NYHA Class (ρ = -0.430), LVEF (r = 0.511), mass index (r = -0.373), LGE (ρ = -0.537), ECV (r = -0.544), and T2 (r = -0.396). Septal CEST correlated significantly with LVEF (r = 0.395), LGE (ρ = -0.330), and ECV (r = -0.391). DATA CONCLUSIONS: This study highlights the potential of CEST MRI to identify cardiac involvement and evaluate disease burden and to give insight into cellular changes intermediary between function and structure in AL amyloidosis patients. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

8.
Neuroradiol J ; : 19714009211026920, 2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34159814

RESUMO

PURPOSE: The trend of atherosclerotic plaque feature evolution is unclear in stroke patients with and without recurrence. We aimed to use three-dimensional whole-brain magnetic resonance vessel wall imaging to quantify the morphological changes of causative lesions during medical therapy in patients with symptomatic intracranial atherosclerotic disease. METHODS: Patients with acute ischemic stroke attributed to intracranial atherosclerotic disease were retrospectively enrolled if they underwent both baseline and follow-up magnetic resonance vessel wall imaging. The morphological features of the causative plaque, including plaque volume, peak normalized wall index, maximum wall thickness, degree of stenosis, pre-contrast plaque-wall contrast ratio, and post-contrast plaque enhancement ratio, were quantified and compared between the non-recurrent and recurrent groups (defined as the recurrence of a vascular event within 18 months of stroke). RESULTS: Twenty-nine patients were included in the final analysis. No significant differences were found in plaque features in the baseline scan between the non-recurrent (n = 22) and recurrent groups (n = 7). The changes in maximum wall thickness (-13.32% vs. 8.93%, P = 0.026), plaque-wall contrast ratio (-0.82% vs. 3.42%, P = 0.005) and plaque enhancement ratio (-11.03% vs. 9.75%, P = 0.019) were significantly different between the non-recurrent and recurrent groups. Univariable logistic regression showed that the increase in plaque-wall contrast ratio (odds ratio 3.22, 95% confidence interval 1.55-9.98, P = 0.003) was related to stroke recurrence. CONCLUSION: Morphological changes of plaque features on magnetic resonance vessel wall imaging demonstrated distinct trends in symptomatic intracranial atherosclerotic disease patients with and without stroke recurrence.

9.
Pancreas ; 50(3): 251-279, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33835956

RESUMO

ABSTRACT: Despite considerable research efforts, pancreatic cancer is associated with a dire prognosis and a 5-year survival rate of only 10%. Early symptoms of the disease are mostly nonspecific. The premise of improved survival through early detection is that more individuals will benefit from potentially curative treatment. Artificial intelligence (AI) methodology has emerged as a successful tool for risk stratification and identification in general health care. In response to the maturity of AI, Kenner Family Research Fund conducted the 2020 AI and Early Detection of Pancreatic Cancer Virtual Summit (www.pdac-virtualsummit.org) in conjunction with the American Pancreatic Association, with a focus on the potential of AI to advance early detection efforts in this disease. This comprehensive presummit article was prepared based on information provided by each of the interdisciplinary participants on one of the 5 following topics: Progress, Problems, and Prospects for Early Detection; AI and Machine Learning; AI and Pancreatic Cancer-Current Efforts; Collaborative Opportunities; and Moving Forward-Reflections from Government, Industry, and Advocacy. The outcome from the robust Summit conversations, to be presented in a future white paper, indicate that significant progress must be the result of strategic collaboration among investigators and institutions from multidisciplinary backgrounds, supported by committed funders.

10.
IEEE Trans Med Imaging ; 40(8): 2170-2181, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33856986

RESUMO

Cine cardiac magnetic resonance imaging (MRI) is widely used for the diagnosis of cardiac diseases thanks to its ability to present cardiovascular features in excellent contrast. As compared to computed tomography (CT), MRI, however, requires a long scan time, which inevitably induces motion artifacts and causes patients' discomfort. Thus, there has been a strong clinical motivation to develop techniques to reduce both the scan time and motion artifacts. Given its successful applications in other medical imaging tasks such as MRI super-resolution and CT metal artifact reduction, deep learning is a promising approach for cardiac MRI motion artifact reduction. In this paper, we propose a novel recurrent generative adversarial network model for cardiac MRI motion artifact reduction. This model utilizes bi-directional convolutional long short-term memory (ConvLSTM) and multi-scale convolutions to improve the performance of the proposed network, in which bi-directional ConvLSTMs handle long-range temporal features while multi-scale convolutions gather both local and global features. We demonstrate a decent generalizability of the proposed method thanks to the novel architecture of our deep network that captures the essential relationship of cardiovascular dynamics. Indeed, our extensive experiments show that our method achieves better image quality for cine cardiac MRI images than existing state-of-the-art methods. In addition, our method can generate reliable missing intermediate frames based on their adjacent frames, improving the temporal resolution of cine cardiac MRI sequences.


Assuntos
Artefatos , Processamento de Imagem Assistida por Computador , Humanos , Imageamento por Ressonância Magnética , Imagem Cinética por Ressonância Magnética , Movimento (Física) , Redes Neurais de Computação
11.
Magn Reson Med ; 86(2): 637-647, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33768617

RESUMO

PURPOSE: (1) To investigate the effect of internal localized movement on 3DMR intracranial vessel wall imaging and (2) to develop a novel motion-compensation approach combining volumetric navigator (vNav) and self-gating (SG) to simultaneously compensate for bulk and localized movements. METHODS: A 3D variable-flip-angle turbo spin-echo (ie, SPACE) sequence was modified to incorporate vNav and SG modules. The SG signals from the center k-space line are acquired at the beginning of each TR to detect localized motion-affected TRs. The vNavs from low-resolution 3D EPI are acquired to identify bulk head motion. Fifteen healthy subjects and 3 stroke patients were recruited in this study. Overall image quality (0-poor to 4-excellent) and vessel wall sharpness were compared among the scenarios with and without bulk and/or localized motion and/or the proposed compensation strategies. RESULTS: Localized motion reduced wall sharpness, which was significantly mitigated by SG (ie, outer boundary of basilar artery: 0.68 ± 0.27 vs 0.86 ± 0.17; P = .037). When motion occurred, the overall image quality and vessel wall sharpness obtained with vNav-SG SPACE were significantly higher than those obtained with conventional SPACE (ie, basilarartery outer boundary sharpness: 0.73 ± 0.24 vs 0.94 ± 0.24; P = .033), yet comparable to those obtained in motion-free scans (ie, basilarartery outer boundary sharpness: 0.94 ± 0.24 vs 0.96 ± 0.31; P = .815). CONCLUSION: Localized movements can induce considerable artifacts in intracranial vessel wall imaging. The vNav-SG approach is capable of compensating for both bulk and localized motions.


Assuntos
Aumento da Imagem , Angiografia por Ressonância Magnética , Artefatos , Humanos , Interpretação de Imagem Assistida por Computador , Imageamento Tridimensional , Movimento (Física)
12.
J Cardiovasc Magn Reson ; 23(1): 25, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33715636

RESUMO

BACKGROUND: Contrast-enhanced (CE) steady-state free precession (SSFP) CMR at 1.5T has been shown to be a valuable alternative to T2-based methods for the detection and quantifications of area-at-risk (AAR) in acute myocardial infarction (AMI) patients. However, CE-SSFP's capacity for assessment of AAR at 3T has not been investigated. We examined the clinical utility of CE-SSFP and T2-STIR for the retrospective assessment of AAR at 3T with single-photon-emission-computed tomography (SPECT) validation. MATERIALS AND METHODS: A total of 60 AMI patients (ST-elevation AMI, n = 44;  non-ST-elevation AMI, n = 16) were recruited into the CMR study between 3 and 7 days post revascularization. All patients underwent T2-STIR, CE-bSSFP and late-gadolinium-enhancement CMR. For validation, SPECT images were acquired in a subgroup of patients (n = 30). RESULTS: In 53 of 60 patients (88 %), T2-STIR was of diagnostic quality compared with 54 of 60 (90 %) with CE-SSFP. In a head-to-head per-slice comparison (n = 365), there was no difference in AAR quantified using T2-STIR and CE-SSFP (R2 = 0.92, p < 0.001; bias:-0.4 ± 0.8 cm2, p = 0.46). On a per-patient basis, there was good agreement between CE-SSFP (n = 29) and SPECT (R2 = 0.86, p < 0.001; bias: - 1.3 ± 7.8 %LV, p = 0.39) for AAR determination. T2-STIR also showed good agreement with SPECT for AAR measurement (R2 = 0.81, p < 0.001, bias: 0.5 ± 11.1 %LV, p = 0.81). There was also a strong agreement between CE-SSFP and T2-STIR with respect to the assessment of AAR on per-patient analysis (R2 = 0.84, p < 0.001, bias: - 2.1 ± 10.1 %LV, p = 0.31). CONCLUSIONS: At 3T, both CE-SSFP and T2-STIR can retrospectively quantify the at-risk myocardium with high accuracy.


Assuntos
Imagem Cinética por Ressonância Magnética , Miocárdio/patologia , Infarto do Miocárdio sem Supradesnível do Segmento ST/diagnóstico por imagem , Infarto do Miocárdio com Supradesnível do Segmento ST/diagnóstico por imagem , Tomografia Computadorizada de Emissão de Fóton Único , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio sem Supradesnível do Segmento ST/patologia , Infarto do Miocárdio sem Supradesnível do Segmento ST/terapia , Intervenção Coronária Percutânea/efeitos adversos , Intervenção Coronária Percutânea/instrumentação , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Infarto do Miocárdio com Supradesnível do Segmento ST/patologia , Infarto do Miocárdio com Supradesnível do Segmento ST/terapia , Stents , Sobrevivência de Tecidos , Resultado do Tratamento
14.
Clin Neurol Neurosurg ; 202: 106516, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33548879

RESUMO

PURPOSE: Cerebral venous thrombosis (CVT) has various clinical presentations and has a median onset delay of 7 days. So it is important to find more identifiable early imaging manifestations for CVT. METHOD: This was a retrospective study. Patients with CVT (CVT group, n = 26) diagnosed by conventional imaging techniques (magnetic resonance imaging and/or digital subtraction angiogram) and patients with symptomatic intracranial atherosclerosis (control group, n = 30) were included. Magnetic resonance black-blood thrombus imaging (MRBTI) technique had been performed in both groups. The CVT group was divided into 3 groups based on the duration of clinical onset: ≤7 days (group 1), between 7 and 30 days (group 2), and >30 days (group 3). Pathological pachymeningeal enhancement and its characteristics were analyzed between the CVT group and the control group. RESULTS: Pathological pachymeningeal enhancement was found in 14 CVT patients (54 %) and none in control group (P value = 0.000). The bilateral pathological pachymeningeal enhancement was involved in 10 CVT patients, 6 patients were asymmetric, and 4 patients had ipsilateral enhancement. Asymmetric pathological pachymeningeal enhancement was 71 % and predominantly located on the thrombosed sinus side. Strong enhancement was found in the venous sinus wall beside the thrombus. Pathological pachymeningeal enhancement percentages of three subgroups were 75 % in group 1, 55 % in group 2, and 29 % in group 3 and had no statistical differences (p value = 0.198). CONCLUSIONS: Current findings suggest asymmetrical pathological pachymeningeal enhancement was associated was CVT and may be a new imaging feature for CVT.

15.
Int J Cardiol ; 331: 1-7, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33545261

RESUMO

BACKGROUND: Ischemia with no obstructive coronary artery disease (INOCA) is prevalent in women and is associated with increased risk of developing heart failure with preserved ejection fraction (HFpEF); however, the mechanism(s) contributing to this progression remains unclear. Given that diastolic dysfunction is common in women with INOCA, defining mechanisms related to diastolic dysfunction in INOCA could identify therapeutic targets to prevent HFpEF. METHODS: Cardiac MRI was performed in 65 women with INOCA and 12 reference controls. Diastolic function was defined by left ventricular early diastolic circumferential strain rate (eCSRd). Contributors to diastolic dysfunction were chosen a priori as coronary vascular dysfunction (myocardial perfusion reserve index [MPRI]), diffuse myocardial fibrosis (extracellular volume [ECV]), and aortic stiffness (aortic pulse wave velocity [aPWV]). RESULTS: Compared to controls, eCSRd was lower in INOCA (1.61 ± 0.33/s vs. 1.36 ± 0.31/s, P = 0.016); however, this difference was not exaggerated when the INOCA group was sub-divided by low and high MPRI (P > 0.05) nor was ECV elevated in INOCA (29.0 ± 1.9% vs. 28.0 ± 3.2%, control vs. INOCA; P = 0.38). However, aPWV was higher in INOCA vs. controls (8.1 ± 3.2 m/s vs. 6.1 ± 1.5 m/s; P = 0.045), and was associated with eCSRd (r = -0.50, P < 0.001). By multivariable linear regression analysis, aPWV was an independent predictor of decreased eCSRd (standardized ß = -0.39, P = 0.003), as was having an elevated left ventricular mass index (standardized ß = -0.25, P = 0.024) and lower ECV (standardized ß = 0.30, P = 0.003). CONCLUSIONS: These data provide mechanistic insight into diastolic dysfunction in women with INOCA, identifying aortic stiffness and ventricular remodeling as putative therapeutic targets.


Assuntos
Doença da Artéria Coronariana , Insuficiência Cardíaca , Disfunção Ventricular Esquerda , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/epidemiologia , Feminino , Humanos , Isquemia , Imageamento por Ressonância Magnética , Análise de Onda de Pulso , Volume Sistólico , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/epidemiologia , Função Ventricular Esquerda
16.
J Cardiovasc Magn Reson ; 23(1): 12, 2021 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-33627144

RESUMO

BACKGROUND: Coronary hyper-intense plaque (CHIP) detected on T1-weighted cardiovascular magnetic resonance (CMR) has been shown to associate with vulnerable plaque features and worse outcomes in low- and intermediate-risk populations. However, the prevalence of CHIP and its clinical significance in the higher-risk acute coronary syndrome (ACS) population have not been systematically studied. This study aims to assess the relationship between CHIP and ACS clinical severity using intracoronary optical coherence tomography (OCT) as the reference. METHODS: A total of 62 patients with known or suspected coronary artery disease were prospectively enrolled including a clinically diagnosed ACS group (n = 50) and a control group with stable angina pectoris (n = 12). The ACS group consisted of consecutive patients including unstable angina pectoris (n = 27), non-ST-segment-elevation myocardial infarction (non-STEMI) (n = 8), and ST-segment-elevation myocardial infarction (STEMI) (n = 15), respectively. All patients underwent non-contrast coronary CMR to determine the plaque-to-myocardium signal intensity ratio (PMR). RESULTS: Among the four groups of patients, a progressive increase in the prevalence of CHIPs (stable angina, 8%; unstable angina, 26%; non-STEMI, 38%; STEMI, 67%; p = 0.009), and PMR values (stable angina, 1.1; unstable angina, 1.2; non-STEMI, 1.3; STEMI, 1.6; median values, P = 0.004) were observed. Thrombus (7/8, 88% vs. 4/22, 18%, p = 0.001) and plaque rupture (5/8, 63% vs. 2/22, 9%, p = 0.007) were significantly more prevalent in CHIPs than in plaques without hyper-intensity. Elevated PMR was associated with high-risk plaque features including plaque rupture, thrombus, and intimal vasculature. A positive correlation was observed between PMR and the number of high-risk plaque features identified by OCT (r = 0.44, p = 0.015). CONCLUSIONS: The prevalence of CHIPs and PMR are positively associated with the disease severity and high-risk plaque morphology in ACS.


Assuntos
Síndrome Coronariana Aguda/diagnóstico por imagem , Doença da Artéria Coronariana/diagnóstico por imagem , Vasos Coronários/diagnóstico por imagem , Imageamento por Ressonância Magnética , Placa Aterosclerótica , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Medição de Risco , Fatores de Risco , Ruptura Espontânea , Índice de Gravidade de Doença , Tomografia de Coerência Óptica
17.
J Cardiovasc Magn Reson ; 23(1): 8, 2021 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-33568177

RESUMO

BACKGROUND: Extracellular volume fraction (ECV) quantification with cardiovascular magnetic resonance (CMR) T1 mapping is a powerful tool for the characterization of focal or diffuse myocardial fibrosis. However, it is technically challenging to acquire high-quality T1 and ECV maps in small animals for preclinical research because of high heart rates and high respiration rates. In this work, we developed an electrocardiogram (ECG)-less, free-breathing ECV mapping method using motion-resolved CMR Multitasking on a 9.4 T small animal CMR system. The feasibility of characterizing diffuse myocardial fibrosis was tested in a rat heart failure model with preserved ejection fraction (HFpEF). METHODS: High-salt fed rats diagnosed with HFpEF (n = 9) and control rats (n = 9) were imaged with the proposed ECV Multitasking technique. A 25-min exam, including two 4-min T1 Multitasking scans before and after gadolinium injection, were performed on each rat. It allows a cardiac temporal resolution of 20 ms for a heart rate of ~ 300 bpm. Myocardial ECV was calculated from the hematocrit (HCT) and fitted T1 values of the myocardium and the blood pool. Masson's trichrome stain was used to measure the extent of fibrosis. Welch's t-test was performed between control and HFpEF groups. RESULTS: ECV was significantly higher in the HFpEF group (22.4% ± 2.5% vs. 18.0% ± 2.1%, P = 0.0010). A moderate correlation between the ECV and the extent of fibrosis was found (R = 0.59, P = 0.0098). CONCLUSIONS: Motion-resolved ECV Multitasking CMR can quantify ECV in the rat myocardium at high heart rates without ECG triggering or respiratory gating. Elevated ECV found in the HFpEF group is consistent with previous human studies and well correlated with histological data. This technique has the potential to be a viable imaging tool for myocardial tissue characterization in small animal models.


Assuntos
Técnicas de Imagem de Sincronização Cardíaca , Insuficiência Cardíaca/diagnóstico por imagem , Frequência Cardíaca , Imageamento por Ressonância Magnética , Respiração , Volume Sistólico , Função Ventricular Esquerda , Animais , Modelos Animais de Doenças , Estudos de Viabilidade , Fibrose , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/fisiopatologia , Hipertensão/etiologia , Hipertensão/fisiopatologia , Masculino , Miocárdio/patologia , Valor Preditivo dos Testes , Ratos Endogâmicos Dahl , Cloreto de Sódio na Dieta
18.
Eur Radiol ; 31(7): 4548-4556, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33447859

RESUMO

OBJECTIVES: This study aimed to investigate the association between dilation and proliferation and anastomosis of perforating arteries, and intracranial hemorrhage in moyamoya disease (MMD) patients, using high-resolution magnetic resonance imaging (HRMRI). METHODS: Adult patients with MMD at advanced stages were prospectively enrolled and underwent HRMRI exams. Dilation and proliferation of the lenticulostriate artery (LSA), medullary artery, and anterior or posterior choroidal arteries (AChA or PChA) were assessed. Abnormal anastomoses were identified between (1) the LSA and the medullary or insular arteries; (2) the thalamo-geniculate, thalamo-tuberal, or thalamo-perforating arteries and the medullary or insular arteries; and (3) the AChA or PChA and the medullary or insular arteries. The association between these variables and hemorrhagic events was calculated using univariate and multivariate analyses. RESULTS: Fifty patients (14 men; mean age, 35.4 ± 9.7 years) were finally analyzed, including 17 hemorrhagic patients and 33 non-hemorrhagic patients. The inter-rater agreement for the qualitative evaluation of perforating arteries was good. Dilation and proliferation of the AChA or PChA (88.2% versus 54.5%, p = 0.027), and choroidal anastomosis (64.7% versus 18.2%, p = 0.002) were more frequently observed in patients with hemorrhage. Multivariate logistic regression showed that choroidal anastomosis remained significantly associated with hemorrhage (odds ratio = 5.95, 95% confidence interval = 1.21-29.25, p = 0.028). CONCLUSIONS: Choroidal anastomosis is independently associated with hemorrhagic events in adult patients with MMD at advanced stages. HRMRI can provide detailed information on both the anatomies and abnormal collaterals in MMD, which facilitates risk estimates of bleeding in MMD. KEY POINTS: • High-resolution magnetic resonance imaging allows for the evaluation of perforating arteries in patients with moyamoya disease. • Choroidal anastomosis is associated with hemorrhagic events in patients with moyamoya disease. • High-resolution magnetic resonance imaging might facilitate further grading and classification of moyamoya vessels.


Assuntos
Doença de Moyamoya , Adulto , Anastomose Cirúrgica , Biomarcadores , Angiografia Cerebral , Humanos , Hemorragias Intracranianas/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Doença de Moyamoya/complicações , Doença de Moyamoya/diagnóstico por imagem
19.
Atherosclerosis ; 319: 72-78, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33486353

RESUMO

BACKGROUND AND AIMS: Intracranial atherosclerotic disease (ICAD) is a major etiologic cause for acute ischemic stroke (AIS) and transient ischemic attack (TIA). The study was designed to investigate if differential morphological features exist in symptomatic atherosclerotic lesions between AIS and TIA patients. METHODS: The culprit plaques from 45 AIS patients and 42 TIA patients were analyzed for the degree of stenosis, vessel wall irregularity, normalized wall index (NWI), remodeling index, plaque-wall contrast ratio (CR), high signal intensity on T1-weighted images, plaque enhancement ratio and enhancement grade. These plaque features along with clinical characteristics were compared between AIS and TIA groups as well as between their stenosis degree-matched subgroups. RESULTS: Overall, grade 2 enhancement (OR 3.85, 95%CI 1.42-10.46, p = 0.006) and hyperlipidemia (OR 3.04, 95%CI 1.13-8.22, p = 0.025) were independent indicators for AIS, whereas high NWI (OR 1.47, 95%CI 0.76-2.86, p = 0.004) was associated with TIA. In the comparison between the subgroups with moderate (30%-69%) stenosis, high plaque-wall CR (OR 5.38, 95%CI 1.39-20.75, p = 0.008) was associated with AIS, whereas high NWI (OR 2.50, 95%CI 0.61-10.00, p = 0.006) was associated with TIA. CONCLUSIONS: Our study reveals differential morphological features in symptomatic ICAD lesions between AIS and TIA patients. Probing these features with MR vessel wall imaging may provide insights into the prognosis of patients with ICAD.


Assuntos
Aterosclerose , Isquemia Encefálica , Arteriosclerose Intracraniana , Ataque Isquêmico Transitório , AVC Isquêmico , Placa Aterosclerótica , Acidente Vascular Cerebral , Isquemia Encefálica/diagnóstico por imagem , Humanos , Arteriosclerose Intracraniana/diagnóstico por imagem , Ataque Isquêmico Transitório/diagnóstico por imagem , Ataque Isquêmico Transitório/etiologia , Acidente Vascular Cerebral/diagnóstico por imagem
20.
Magn Reson Med ; 85(6): 3096-3111, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33427334

RESUMO

PURPOSE: To develop a low-dose Multitasking DCE technique (LD-MT-DCE) for breast imaging, enabling dynamic T1 mapping-based quantitative characterization of tumor blood flow and vascular properties with whole-breast coverage, a spatial resolution of 0.9 × 0.9 × 1.1 mm3 , and a temporal resolution of 1.4 seconds using a 20% gadolinium dose (0.02 mmol/kg). METHODS: Magnetic resonance Multitasking was used to reconstruct 5D images with three spatial dimensions, one T1 recovery dimension for dynamic T1 quantification, and one DCE dimension for contrast kinetics. Kinetic parameters F p , v p , K trans , and v e were estimated from dynamic T1 maps using the two-compartment exchange model. The LD-MT-DCE repeatability and agreement against standard-dose MT-DCE were evaluated in 20 healthy subjects. In 7 patients with triple-negative breast cancer, LD-MT-DCE image quality and diagnostic results were compared with that of standard-dose clinical DCE in the same imaging session. One-way unbalanced analysis of variance with Tukey test was performed to evaluate the statistical significance of the kinetic parameters between control and patient groups. RESULTS: The LD-MT-DCE technique was repeatable, agreed with standard-dose MT-DCE, and showed excellent image quality. The diagnosis using LD-MT-DCE matched well with clinical results. The values of F p , v p , and K trans were significantly different between malignant tumors and normal breast tissue (P < .001, < .001, and < .001, respectively), and between malignant and benign tumors (P = .020, .003, and < .001, respectively). CONCLUSION: The LD-MT-DCE technique was repeatable and showed excellent image quality and equivalent diagnosis compared with standard-dose clinical DCE. The estimated kinetic parameters were capable of differentiating between normal breast tissue and benign and malignant tumors.


Assuntos
Neoplasias da Mama , Mama/diagnóstico por imagem , Neoplasias da Mama/diagnóstico por imagem , Meios de Contraste , Gadolínio , Humanos , Imageamento por Ressonância Magnética
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