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Contrast transport models are widely used to quantify blood flow and transport in dynamic contrast-enhanced magnetic resonance imaging. These models analyze the time course of the contrast agent concentration, providing diagnostic and prognostic value for many biological systems. Thus, ensuring accuracy and repeatability of the model parameter estimation is a fundamental concern. In this work, we analyze the structural and practical identifiability of a class of nested compartment models pervasively used in analysis of MRI data. We combine artificial and real data to study the role of noise in model parameter estimation. We observe that although all the models are structurally identifiable, practical identifiability strongly depends on the data characteristics. We analyze the impact of increasing data noise on parameter identifiability and show how the latter can be recovered with increased data quality. To complete the analysis, we show that the results do not depend on specific tissue characteristics or the type of enhancement patterns of contrast agent signal.
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Meios de Contraste , Imageamento por Ressonância Magnética , Meios de Contraste/química , Meios de Contraste/farmacocinética , Imageamento por Ressonância Magnética/métodos , Humanos , Modelos Biológicos , Biologia Computacional , Simulação por ComputadorRESUMO
PURPOSE: To develop an MR multitasking-based dynamic imaging for cerebrovascular evaluation (MT-DICE) technique for simultaneous quantification of permeability and leakage-insensitive perfusion with a single-dose contrast injection. METHODS: MT-DICE builds on a saturation-recovery prepared multi-echo fast low-angle shot sequence. The k-space is randomly sampled for 7.6 min, with single-dose contrast agent injected 1.5 min into the scan. MR multitasking is used to model the data into six dimensions, including three spatial dimensions for whole-brain coverage, a saturation-recovery time dimension, and a TE dimension for dynamic T 1 $$ {\mathrm{T}}_1 $$ and T 2 * $$ {\mathrm{T}}_2^{\ast } $$ quantification, respectively, and a contrast dynamics dimension for capturing contrast kinetics. The derived pixel-wise T 1 / T 2 * $$ {\mathrm{T}}_1/{\mathrm{T}}_2^{\ast } $$ time series are converted into contrast concentration-time curves for calculation of kinetic metrics. The technique was assessed for its agreement with reference methods in T 1 $$ {\mathrm{T}}_1 $$ and T 2 * $$ {\mathrm{T}}_2^{\ast } $$ measurements in eight healthy subjects and, in three of them, inter-session repeatability of permeability and leakage-insensitive perfusion parameters. Its feasibility was also demonstrated in four patients with brain tumors. RESULTS: MT-DICE T 1 / T 2 * $$ {\mathrm{T}}_1/{\mathrm{T}}_2^{\ast } $$ values of normal gray matter and white matter were in excellent agreement with reference values (intraclass correlation coefficients = 0.860/0.962 for gray matter and 0.925/0.975 for white matter ). Both permeability and perfusion parameters demonstrated good to excellent intersession agreement with the lowest intraclass correlation coefficients at 0.694. Contrast kinetic parameters in all healthy subjects and patients were within the literature range. CONCLUSION: Based on dynamic T 1 / T 2 * $$ {\mathrm{T}}_1/{\mathrm{T}}_2^{\ast } $$ mapping, MT-DICE allows for simultaneous quantification of permeability and leakage-insensitive perfusion metrics with a single-dose contrast injection.
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Meios de Contraste , Imageamento por Ressonância Magnética , Humanos , Imageamento por Ressonância Magnética/métodos , Perfusão , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , PermeabilidadeRESUMO
The goal of the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) Stroke Recovery working group is to understand brain and behavior relationships using well-powered meta- and mega-analytic approaches. ENIGMA Stroke Recovery has data from over 2,100 stroke patients collected across 39 research studies and 10 countries around the world, comprising the largest multisite retrospective stroke data collaboration to date. This article outlines the efforts taken by the ENIGMA Stroke Recovery working group to develop neuroinformatics protocols and methods to manage multisite stroke brain magnetic resonance imaging, behavioral and demographics data. Specifically, the processes for scalable data intake and preprocessing, multisite data harmonization, and large-scale stroke lesion analysis are described, and challenges unique to this type of big data collaboration in stroke research are discussed. Finally, future directions and limitations, as well as recommendations for improved data harmonization through prospective data collection and data management, are provided.
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Imageamento por Ressonância Magnética , Neuroimagem , Acidente Vascular Cerebral , Humanos , Estudos Multicêntricos como Assunto , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/patologia , Acidente Vascular Cerebral/fisiopatologia , Reabilitação do Acidente Vascular CerebralRESUMO
PURPOSE: Patterns of extension of pituitary adenomas (PA) may vary according to PA subtype. Understanding extrasellar extension patterns in growth hormone PAs (GHPA) vis-a-vis nonfunctional PAs (NFPAs) may provide insights into the biology of GHPA and future treatment avenues. METHODS: Preoperative MR imaging (MRI) in 179 consecutive patients treated surgically for NFPA (n = 139) and GHPA (n = 40) were analyzed to determine patterns of extrasellar growth. Extension was divided into two principal directions: cranio-caudal (measured by infrasellar/suprasellar extension), and lateral cavernous sinus invasion (CSI) determined by Knosp grading score of 3-4. Suprasellar extension was defined as tumor extension superior to the tuberculum sellae- dorsum sellae line, and inferior extension as invasion through the sellar floor into the sphenoid sinus or clivus. Categorical analysis was performed using Fisher's exact test. RESULTS: GHPAs were overall more likely to remain purely intrasellar compared to NFPA (50% vs 26%, p < 0.001). GHPAs, however, were 7 times more likely to exhibit isolated infrasellar extension compared to NFPA (20% vs 2.8%, p = 0.001). Conversely, NFPAs were twice as likely to exhibit isolated suprasellar extension compared to GHPA (60% vs 28%, p < 0.001), as well as combined suprasellar/infrasellar extension (25% vs 3%, p = 0.011). There were no overall differences in CSI between the two subgroups. DISCUSSION: GHPA and NFPA demonstrate distinct extrasellar extension patterns on MRI. GHPAs show proclivity for inferior extension with bony invasion, whereas NFPAs are more likely to exhibit suprasellar extension through the diaphragmatic aperture. These distinctions may have implications into the biology and future treatment of PAs.
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Adenoma , Adenoma Hipofisário Secretor de Hormônio do Crescimento , Hormônio do Crescimento Humano , Neoplasias Hipofisárias , Adenoma/patologia , Adenoma/cirurgia , Adenoma Hipofisário Secretor de Hormônio do Crescimento/patologia , Adenoma Hipofisário Secretor de Hormônio do Crescimento/cirurgia , Humanos , Imageamento por Ressonância Magnética , Neoplasias Hipofisárias/patologia , Neoplasias Hipofisárias/cirurgia , Estudos Retrospectivos , Sela Túrcica/patologia , Seio Esfenoidal/patologiaRESUMO
Cushing's disease manifests as symptoms of glucocorticoid excess secondary to the increased secretion of corticotropin by a corticotroph adenoma in the pituitary gland. Unfortunately, magnetic resonance imaging (MRI) performed at conventional clinical field strengths of 1.5 or 3 Tesla has limited sensitivity for the detection of these pituitary tumors, and radiologic uncertainty often necessitates more invasive workup to confirm diagnosis and guide resection. It has been postulated that higher static magnetic field strengths may increase the adenoma detection rate and thus the utility of MRI for this clinical application. In this report, we describe our initial experience using ultra-high field 7 Tesla (7 T) MRI in patients with suspected Cushing's disease and negative or equivocal imaging at conventional field strengths. We performed contrast-enhanced 7 T pituitary MRI in 10 patients with up to three different T1-weighted sequences and correlated the imaging abnormalities identified with results of histologic evaluation in patients who subsequently underwent resection. We found that 7 T MRI enabled the identification of previously undetected areas of focal pituitary hypoenhancement in 9 patients (90%), of which 7 corresponded histologically to corticotroph adenomas. These early findings suggest an important adjunctive role for ultra-high field MR imaging in the noninvasive clinical workup of suspected Cushing's disease.
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Adenoma Hipofisário Secretor de ACT/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Neoplasias Hipofisárias/diagnóstico por imagem , Meios de Contraste , Feminino , Humanos , Masculino , Meglumina , Compostos Organometálicos , Estudos ProspectivosRESUMO
Physiological properties of tumors can be measured both in vivo and noninvasively by diffusion-weighted imaging and dynamic contrast-enhanced magnetic resonance imaging. Although these techniques have been used for more than two decades to study tumor diffusion, perfusion, and/or permeability, the methods and studies on how to reduce measurement error and bias in the derived imaging metrics is still lacking in the literature. This is of paramount importance because the objective is to translate these quantitative imaging biomarkers (QIBs) into clinical trials, and ultimately in clinical practice. Standardization of the image acquisition using appropriate phantoms is the first step from a technical performance standpoint. The next step is to assess whether the imaging metrics have clinical value and meet the requirements for being a QIB as defined by the Radiological Society of North America's Quantitative Imaging Biomarkers Alliance (QIBA). The goal and mission of QIBA and the National Cancer Institute Quantitative Imaging Network (QIN) initiatives are to provide technical performance standards (QIBA profiles) and QIN tools for producing reliable QIBs for use in the clinical imaging community. Some of QIBA's development of quantitative diffusion-weighted imaging and dynamic contrast-enhanced QIB profiles has been hampered by the lack of literature for repeatability and reproducibility of the derived QIBs. The available research on this topic is scant and is not in sync with improvements or upgrades in MRI technology over the years. This review focuses on the need for QIBs in oncology applications and emphasizes the importance of the assessment of their reproducibility and repeatability. Level of Evidence: 5 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019;49:e101-e121.
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Biomarcadores , Imagem de Difusão por Ressonância Magnética/métodos , Neoplasias/diagnóstico por imagem , Adulto , Idoso , Encéfalo/diagnóstico por imagem , Ensaios Clínicos como Assunto , Meios de Contraste , Feminino , Humanos , Fígado/diagnóstico por imagem , Masculino , Oncologia/normas , Pessoa de Meia-Idade , Estudos Multicêntricos como Assunto , Neuroimagem/métodos , Imagens de Fantasmas , Próstata/diagnóstico por imagem , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Ventilator-associated respiratory infections (tracheobronchitis, pneumonia) contribute significant morbidity and mortality to adults receiving care in intensive care units (ICU). Administration of broad-spectrum intravenous antibiotics, the current standard of care, may have systemic adverse effects. The efficacy of aerosolized antibiotics for treatment of ventilator-associated respiratory infections remains unclear. Our objective was to conduct a systematic review of the efficacy of aerosolized antibiotics in the treatment of ventilator-associated pneumonia (VAP) and tracheobronchitis (VAT), using the Cochrane Collaboration guidelines. METHODS: We conducted a search of three databases (PubMed, Web of Knowledge and the Cochrane Collaboration) for randomized, controlled trials studying the use of nebulized antibiotics in VAP and VAT that measured clinical cure (e.g., change in Clinical Pulmonary Infection Score) as an outcome measurement. We augmented the electronic searches with hand searches of the references for any narrative review articles as well as any article included in the systematic review. Included studies were examined for risk of bias using the Cochrane Handbook's "Risk of Bias" assessment tool. RESULTS: Six studies met full inclusion criteria. For the systemic review's primary outcome (clinical cure), two studies found clinically and statistically significant improvements in measures of VAP cure while four found no statistically significant difference in measurements of cure. No studies found inferiority of aerosolized antibiotics. The included studies had various degrees of biases, particularly in the performance and detection bias domains. Given that outcome measures of clinical cure were not uniform, we were unable to conduct a meta-analysis. CONCLUSIONS: There is insufficient evidence for the use of inhaled antibiotic therapy as primary or adjuvant treatment of VAP or VAT. Additional, better-powered randomized-controlled trials are needed to assess the efficacy of inhaled antibiotic therapy for VAP and VAT.
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Antibacterianos/administração & dosagem , Bronquite/tratamento farmacológico , Pneumonia Associada à Ventilação Mecânica/tratamento farmacológico , Traqueíte/tratamento farmacológico , Administração por Inalação , Antibacterianos/uso terapêutico , Bronquite/etiologia , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/etiologia , Humanos , Respiração Artificial/efeitos adversos , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/etiologia , Traqueíte/etiologia , Ventiladores Mecânicos/efeitos adversosRESUMO
OBJECTIVE: Intraoperative contrast-enhanced ultrasound (iCEUS) offers dynamic imaging and provides functional data in real time. However, no standardized protocols or validated quantitative data exist to guide its routine use in neurosurgery. The authors aimed to provide further clinical data on the versatile application of iCEUS through a technical note and illustrative case series. METHODS: Five patients undergoing craniotomies for suspected tumors were included. iCEUS was performed using a contrast agent composed of lipid shell microspheres enclosing perflutren (octafluoropropane) gas. Perfusion data were acquired through a time-intensity curve analysis protocol obtained using iCEUS prior to biopsy and/or resection of all lesions. RESULTS: Three primary tumors (gemistocytic astrocytoma, glioblastoma multiforme, and meningioma), 1 metastatic lesion (melanoma), and 1 tumefactive demyelinating lesion (multiple sclerosis) were assessed using real-time iCEUS. No intraoperative complications occurred following multiple administrations of contrast agent in all cases. In all neoplastic cases, iCEUS replicated enhancement patterns observed on preoperative Gd-enhanced MRI, facilitated safe tumor debulking by differentiating neoplastic tissue from normal brain parenchyma, and helped identify arterial feeders and draining veins in and around the surgical cavity. Intraoperative CEUS was also useful in guiding a successful intraoperative needle biopsy of a cerebellar tumefactive demyelinating lesion obtained during real-time perfusion analysis. CONCLUSIONS: Intraoperative CEUS has potential for safe, real-time, dynamic contrast-based imaging for routine use in neurooncological surgery and image-guided biopsy. Intraoperative CEUS eliminates the effect of anatomical distortions associated with standard neuronavigation and provides quantitative perfusion data in real time, which may hold major implications for intraoperative diagnosis, tissue differentiation, and quantification of extent of resection. Further prospective studies will help standardize the role of iCEUS in neurosurgery.
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Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/cirurgia , Sistemas Computacionais/estatística & dados numéricos , Craniotomia/métodos , Monitorização Intraoperatória/estatística & dados numéricos , Ultrassonografia de Intervenção/estatística & dados numéricos , Idoso de 80 Anos ou mais , Meios de Contraste , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Intraoperatória/métodos , Procedimentos Neurocirúrgicos/métodos , Estudos Retrospectivos , Ultrassonografia de Intervenção/métodosRESUMO
Dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) is used to track the first pass of an exogenous, paramagnetic, nondiffusible contrast agent through brain tissue, and has emerged as a powerful tool in the characterization of brain tumor hemodynamics. DSC-MRI parameters can be helpful in many aspects, including tumor grading, prediction of treatment response, likelihood of malignant transformation, discrimination between tumor recurrence and radiation necrosis, and differentiation between true early progression and pseudoprogression. This review aims to provide a conceptual overview of the underlying principles of DSC-MRI of the brain for clinical neuroradiologists, scientists, or students wishing to improve their understanding of the technical aspects, pitfalls, and controversies of DSC perfusion MRI of the brain. Future consensus on image acquisition parameters and postprocessing of DSC-MRI will most likely allow this technique to be evaluated and used in high-quality multicenter studies and ultimately help guide clinical care.
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Neoplasias Encefálicas/diagnóstico , Imageamento por Ressonância Magnética/métodos , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/terapia , Meios de Contraste , Progressão da Doença , Hemodinâmica , Humanos , Gradação de Tumores , Recidiva Local de Neoplasia/diagnósticoRESUMO
INTRODUCTION: The specific goal of this study was to determine whether the inclusion of MRS had a measureable and positive impact on the accuracy of pre-surgical MR examinations of untreated pediatric brain tumors over that of MRI alone in clinical practice. METHODS: Final imaging reports of 120 pediatric patients with newly detected brain tumors who underwent combined MRI/MRS examinations were retrospectively reviewed. Final pathology was available in all cases. Group A comprised 60 subjects studied between June 2001 and January 2005, when MRS was considered exploratory and radiologists utilized only conventional MRI to arrive at a diagnosis. For group B, comprising 60 subjects studied between January 2005 and March 2008, the radiologists utilized information from both MRI and MRS. Furthermore, radiologists revisited group A (blind review, time lapse >4 years) to determine whether the additional information from MRS would have altered their interpretation. RESULTS: Sixty-three percent of patients in group A were diagnosed correctly, whereas in 10% the report was partially correct with the final tumor type mentioned (but not mentioned as most likely tumor), while in 27% of cases the reports were wrong. For group B, the diagnoses were correct in 87%, partially correct in 5%, and incorrect in 8% of the cases, which is a significant improvement (p < 0.005). Re-review of combined MRI and MRS of group A resulted 87% correct, 7% partially correct, and 7% incorrect diagnoses, which is a significant improvement over the original diagnoses (p < 0.05). CONCLUSION: Adding MRS to conventional MRI significantly improved diagnostic accuracy in preoperative pediatric patients with untreated brain tumors.
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Neoplasias Encefálicas/diagnóstico , Imageamento por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/métodos , Imagem Multimodal , Criança , Feminino , Humanos , MasculinoRESUMO
The quantitative, multiparametric assessment of brain lesions requires coregistering different parameters derived from MRI sequences. This will be followed by analysis of the voxel values of the ROI within the sequences and calculated parametric maps, and deriving multiparametric models to classify imaging data. There is a need for an intuitive, automated quantitative processing framework that is generalized and adaptable to different clinical and research questions. As such flexible frameworks have not been previously described, we proceeded to construct a quantitative post-processing framework with commonly available software components. Matlab was chosen as the programming/integration environment, and SPM was chosen as the coregistration component. Matlab routines were created to extract and concatenate the coregistration transforms, take the coregistered MRI sequences as inputs to the process, allow specification of the ROI, and store the voxel values to the database for statistical analysis. The functionality of the framework was validated using brain tumor MRI cases. The implementation of this quantitative post-processing framework enables intuitive creation of multiple parameters for each voxel, facilitating near real-time in-depth voxel-wise analysis. Our initial empirical evaluation of the framework is an increased usage of analysis requiring post-processing and increased number of simultaneous research activities by clinicians and researchers with non-technical backgrounds. We show that common software components can be utilized to implement an intuitive real-time quantitative post-processing framework, resulting in improved scalability and increased adoption of post-processing needed to answer important diagnostic questions.
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Encefalopatias/diagnóstico , Mapeamento Encefálico/métodos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Software , Bases de Dados Factuais , Humanos , Sensibilidade e EspecificidadeRESUMO
BACKGROUND AND OBJECTIVES: Suprasellar tumors, particularly pituitary adenomas (PAs), commonly present with visual decline, and the endoscopic endonasal transsphenoidal approach (EETA) is the primary management for optic apparatus decompression. Patients presenting with complete preoperative monocular blindness comprise a high-risk subgroup, given concern for complete blindness. This retrospective cohort study evaluates outcomes after EETA for patients with PA presenting with monocular blindness. METHODS: Retrospective analysis of all EETA cases at our institution from June 2012 to August 2023 was performed. Inclusion criteria included adults with confirmed PA and complete monocular blindness, defined as no light perception, and a relative afferent pupillary defect secondary to tumor mass effect. RESULTS: Our cohort includes 15 patients (9 males, 6 females), comprising 2.4% of the overall PA cohort screened. The mean tumor diameter was 3.8 cm, with 6 being giant PAs (>4 cm). The mean duration of preoperative monocular blindness was 568 days. Additional symptoms included contralateral visual field defects (n = 11) and headaches (n = 10). Two patients presented with subacute PA apoplexy. Gross total resection was achieved in 46% of patients, reflecting tumor size and invasiveness. Postoperatively, 2 patients experienced improvement in their effectively blind eye and 2 had improved visual fields of the contralateral eye. Those with improvements were operated within 10 days of presentation, and no patients experienced worsened vision. CONCLUSION: This is the first series of EETA outcomes in patients with higher-risk PA with monocular blindness on presentation. In these extensive lesions, vision remained stable for most without further decline and improvement from monocular blindness was observed in a small subset of patients with no light perception and relative afferent pupillary defect. Timing from vision loss to surgical intervention seemed to be associated with improvement. From a surgical perspective, caution is warranted to protect remaining vision and we conclude that EETA is safe in the management of these patients.
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Adenoma , Cegueira , Neoplasias Hipofisárias , Humanos , Masculino , Neoplasias Hipofisárias/cirurgia , Neoplasias Hipofisárias/complicações , Neoplasias Hipofisárias/diagnóstico por imagem , Feminino , Cegueira/etiologia , Cegueira/cirurgia , Pessoa de Meia-Idade , Adenoma/cirurgia , Adenoma/complicações , Estudos Retrospectivos , Adulto , Idoso , Neuroendoscopia/métodos , Resultado do Tratamento , Cirurgia Endoscópica por Orifício Natural/métodosRESUMO
Radiographic assessment plays a crucial role in the management of patients with central nervous system (CNS) tumors, aiding in treatment planning and evaluation of therapeutic efficacy by quantifying response. Recently, an updated version of the Response Assessment in Neuro-Oncology (RANO) criteria (RANO 2.0) was developed to improve upon prior criteria and provide an updated, standardized framework for assessing treatment response in clinical trials for gliomas in adults. This article provides an overview of significant updates to the criteria including (1) the use of a unified set of criteria for high and low grade gliomas in adults; (2) the use of the post-radiotherapy MRI scan as the baseline for evaluation in newly diagnosed high-grade gliomas; (3) the option for the trial to mandate a confirmation scan to more reliably distinguish pseudoprogression from tumor progression; (4) the option of using volumetric tumor measurements; and (5) the removal of subjective non-enhancing tumor evaluations in predominantly enhancing gliomas (except for specific therapeutic modalities). Step-by-step pragmatic guidance is hereby provided for the neuroradiologist and imaging core lab involved in operationalization and technical execution of RANO 2.0 in clinical trials, including the display of representative cases and in-depth discussion of challenging scenarios.ABBREVIATIONS: BTIP = Brain Tumor Imaging Protocol; CE = Contrast-Enhancing; CNS = Central Nervous System; CR = Complete Response; ECOG = Eastern Cooperative Oncology Group; HGG = High-Grade Glioma; IDH = Isocitrate Dehydrogenase; IRF = Independent Radiologic Facility; LGG = Low-Grade Glioma; KPS = Karnofsky Performance Status; MR = Minor Response; mRANO = Modified RANO; NANO = Neurological Assessment in Neuro-Oncology; ORR = Objective Response Rate; OS = Overall Survival; PD = Progressive Disease; PFS = Progression-Free Survival; PR = Partial Response; PsP = Pseudoprogression; RANO = Response Assessment in Neuro-Oncology; RECIST = Response Evaluation Criteria In Solid Tumors; RT = Radiation Therapy; SD = Stable Disease; Tx = Treatment.
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OBJECTIVE: This and its companion article address the 10 most frequently asked questions that radiologists face when planning, performing, processing, and interpreting different MR perfusion studies in CNS imaging. CONCLUSION: Perfusion MRI is a promising tool in assessing stroke, brain tumors, and patients with neurodegenerative diseases. Most of the impediments that have limited the use of perfusion MRI can be overcome to allow integration of these methods into modern neuroimaging protocols.
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Encefalopatias/diagnóstico , Encéfalo/irrigação sanguínea , Meios de Contraste , Angiografia por Ressonância Magnética/métodos , Meios de Contraste/administração & dosagem , Meios de Contraste/efeitos adversos , Gadolínio , Gadolínio DTPA/efeitos adversos , Humanos , Injeções Intravenosas , Angiografia por Ressonância Magnética/efeitos adversos , Compostos Organometálicos/efeitos adversosRESUMO
OBJECTIVE: This article addresses questions that radiologists frequently ask when planning, performing, processing, and interpreting MRI perfusion studies in CNS imaging. CONCLUSION: Perfusion MRI is a promising tool in assessing stroke, brain tumors, and neurodegenerative diseases. Most of the impediments that have limited the use of per-fusion MRI can be overcome to allow integration of these methods into modern neuroimaging protocols.
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Doenças do Sistema Nervoso Central/diagnóstico , Imageamento por Ressonância Magnética/métodos , Neuroimagem/métodos , Doenças do Sistema Nervoso Central/patologia , Meios de Contraste , Humanos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodosRESUMO
BACKGROUND: Atrial intraventricular meningiomas (AIMs) are relatively rare and typically deep-seated tumors that can mandate resection. Compared with transsulcal or transcortical open microscopic approaches, port- or channel-based exoscopic approaches have facilitated a less invasive alternative of tumor access and resection. The authors present a case series of seven patients with AIMs who underwent open microscopic versus channel-based exoscopic resection by a senior neurosurgeon at their institution between 2012 and 2022 to understand patient and tumor features that lent themselves to selection of a particular approach. OBSERVATIONS: In the patients harboring three AIMs selected for channel-based resection, the average AIM diameter (2.9 vs 5.2 cm) was smaller, the AIMs were deeper from the cortical surface (2.5 vs 1.1 cm), and the patients had a shorter average postoperative length of stay (3.3 vs 5.8 days) compared with the four patients who underwent open resection. Gross-total resection was achieved in all cases. Complications for both groups included transient homonymous hemianopsia and aphasia. No recurrences were identified over the follow-up period. LESSONS: The authors demonstrate that channel-based exoscopic resection is safe and effective for AIMs 3 cm in diameter and over 2 cm deep. This may help guide neurosurgeons in future approach selection based on tumor features, including size/volume, location, and depth from cortical surface.
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RATIONALE AND OBJECTIVES: With the development of HER2-directed therapies, identifying non-invasive imaging biomarkers of HER2 expression in breast cancer brain metastases has become increasingly important. The purpose of this study was to investigate whether relative cerebral blood volume (rCBV) from dynamic susceptibility contrast-enhanced (DSC) perfusion MR could help identify the HER2 status of breast cancer brain metastases. MATERIALS AND METHODS: With IRB approval for this HIPAA-compliant cross-sectional study and a waiver of informed consent, we queried our institution's electronic medical record to derive a cohort of 14 histologically proven breast cancer brain metastases with preoperative DSC perfusion MR and HER2 analyses of the resected/biopsied brain specimens from 2011-2021. The rCBV of the lesions was measured and compared using Mann-Whitney tests. Receiver operating characteristic analyses were performed to evaluate the performance of rCBV in identifying HER2 status. RESULTS: The study cohort was comprised of 14 women with a mean age of 56 years (range: 32-81 years) with a total of 14 distinct lesions. The rCBV of HER2-positive breast cancer brain metastases was significantly greater than the rCBV of HER2-negative lesions (8.02 vs 3.97, U=48.00, p=0.001). rCBV differentiated HER2-positive lesions from HER2-negative lesions with an area under the curve of 0.98 (standard error=0.032, p<0.001). The accuracy-maximizing rCBV threshold (4.8) was associated with an accuracy of 93% (13/14), a sensitivity of 100% (7/7), and a specificity of 86% (6/7). CONCLUSION: rCBV may assist in identifying the HER2 status of breast cancer brain metastases, if validated in a large prospective trial.
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Neoplasias Encefálicas , Neoplasias da Mama , Humanos , Feminino , Pessoa de Meia-Idade , Volume Sanguíneo Cerebral , Imageamento por Ressonância Magnética/métodos , Estudos Prospectivos , Neoplasias da Mama/diagnóstico por imagem , Estudos Transversais , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Perfusão , Circulação Cerebrovascular , Meios de ContrasteRESUMO
A 54-year-old male with a history of diabetes mellitus type 2 for 12 years and hypertension was seen in the clinic due to poorly controlled diabetes. Inferior petrosal sinus sampling (IPSS) confirmed Cushing's disease with primary adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma on the right. However, 3T and subsequent 7T MRI showed no visible tumor. An endoscopic transsphenoidal approach was selected to explore the pituitary gland and resect the presumed microadenoma. Tumor was identified in the lateral recess along the right medial cavernous sinus wall and gross-total resection (GTR) was performed. The normal pituitary gland was preserved, and the patient went into remission. The video can be found here: https://stream.cadmore.media/r10.3171/2023.4.FOCVID2324.
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Compartment models are widely used to quantify blood flow and transport in dynamic contrast-enhanced magnetic resonance imaging. These models analyze the time course of the contrast agent concentration, providing diagnostic and prognostic value for many biological systems. Thus, ensuring accuracy and repeatability of the model parameter estimation is a fundamental concern. In this work, we analyze the structural and practical identifiability of a class of nested compartment models pervasively used in analysis of MRI data. We combine artificial and real data to study the role of noise in model parameter estimation. We observe that although all the models are structurally identifiable, practical identifiability strongly depends on the data characteristics. We analyze the impact of increasing data noise on parameter identifiability and show how the latter can be recovered with increased data quality. To complete the analysis, we show that the results do not depend on specific tissue characteristics or the type of enhancement patterns of contrast agent signal.