Large Systems Research Articles

Balance and Walking Speed Outcomes in Individuals Receiving Inpatient Rehabilitation for Acute Cerebellar Stroke.

Cerebellar strokes account for only 2-3% of all strokes occurring annually in the United States but represent a disproportionally higher share of morbidity and mortality. Evidence examining the effect of inpatient rehabilitation on functional outcomes following a cerebellar stroke is limited. This study aimed to examine the effects of inpatient rehabilitation on balance and walking speed in individuals with cerebellar stroke. A secondary purpose of this study was to examine the length of inpatient rehabilitation stay of the included patients. A retrospective analysis was conducted using review of patient records during their inpatient rehabilitation stay from January 2021 to February 2022 at a large hospital system in the southeast United States. Balance and gait outcomes were examined on admission and discharge from inpatient rehabilitation that included physical therapy interventions. A paired t-test examined for changes in outcomes from admission to discharge. Pearson correlation examined for the association between length of stay and outcomes. A total of 15 records were reviewed. There were significant improvements in the Berg Balance Scale (BBS), Postural Assessment Scale for Stroke (PASS), and the 10-Meter Walk Test (10MWT) (p's < 0.01) from admission to discharge with large effect sizes (range d = 0.70-1.67) following inpatient rehabilitation. The average length of stay was 12.67 days (SD = 6.5) and the mean total hours of combined occupational, physical, and speech therapy was 27.33 (SD = 6.52) h. There was a moderate association between length of stay and PASS (r = 0.525, p = 0.04) and BBS (r = 0.546, p = 0.04) outcomes. Patients who underwent inpatient rehabilitation following acute cerebellar strokes demonstrated improvements in balance and gait speed. Study results could assist clinicians designing interventions for patients with cerebellar strokes in the inpatient rehabilitation setting.

Evaluation of an Outpatient Cervical Ripening Program Using Osmotic Dilators and Foley Balloon Catheters.

This study aimed to describe patient characteristics, satisfaction, and outcome measures for patients undergoing outpatient cervical ripening. A retrospective cohort study using electronic health record data from March 2020 to March 2022 from a large health system. The sample included patients with a low-risk singleton pregnancy undergoing outpatient cervical ripening with either an osmotic dilator or Foley balloon catheter. A subset of patients completed satisfaction surveys. Frequencies and means were used to describe the population and conduct comparisons by device type. Inverse probability of treatment weighted estimates were generated to address baseline differences between patients in the two device groups. Outpatient cervical ripening was completed by 120 patients (80 osmotic dilators and 40 Foley balloon catheters). The mean time from insertion to inpatient admission was 16.2 ± 4.8 hours. The mean change in simplified Bishop score (SBS) was 1.8 ± 1.4 and the mean change in dilation was 1.8 ± 1.1 cm. There were no differences in the amount of cervical change by device type. Patients returned earlier than planned 16.7% of the time, primarily for contractions or rupture of membranes. Following outpatient cervical ripening, the time from admission to delivery was 19.9 ± 10.3 hours, with no difference by device type. Vaginal delivery occurred for 74.8% of patients. Patients reported overall satisfaction with the outpatient cervical ripening experience, with the highest satisfaction among those with osmotic dilators. Patients with both device types stated they would recommend outpatient cervical ripening to others, and experienced low levels of stress and discomfort at home prior to hospital admission. Patients participating in outpatient cervical ripening with osmotic dilators or Foley balloon catheters experienced clinically meaningful changes in dilation and SBSs while at home and reported general satisfaction with the outpatient program experience. · Outpatient use of osmotic dilators or Foley balloon catheters improved Bishop scores.. · Patient and device complications were comparable to other research findings.. · Patients reported overall satisfaction with outpatient cervical ripening..

The method of fundamental solutions for multi-particle Stokes flows: Application to a ring-like array of spheres

A method is presented for calculating Stokes flow around multiple particles of arbitrary shape. It uses the Method of Fundamental Solutions (MFS) applied to single particles, combined with an iterative scheme to resolve the many particle-particle hydrodynamic interactions; an approach that is reminiscent of the Method of Reflections. The attractive features of the proposed method are inherited from the MFS — simplicity and accuracy — while providing orders of magnitude computational speed-up for large particle systems. The method is verified through a series of test cases, including those involving strong lubrication forces and non-spherical particles. Unlike applications of the Method of Reflections reported in the literature, the iterative scheme we propose (a block Gauss-Seidel approach to solving a particle-particle interaction matrix) converges for all the cases we consider, for both resistance and mobility problems. The scheme is applied to the study of Stokes flow around ring-like arrays of spheres. We show that the relationship between globally applied velocity or force to the response of individual spheres can be described by just 5 coefficients (or 9 in total) for any given configuration. The results indicate that for 7–10 spheres in sedimentation, there exists a certain spacing that produces steady-state translation of the ring, independent of its orientation. For large numbers of spheres, slender-body theory can be applied to the problem, providing remarkably close agreement to the numerical results over a wide range of parameters.

Measurable Krylov spaces and eigenenergy count in quantum state dynamics

In this work, we propose a quantum-mechanically measurable basis for the computation of spread complexity. Current literature focuses on computing different powers of the Hamiltonian to construct a basis for the Krylov state space and the computation of the spread complexity. We show, through a series of proofs, that time-evolved states with different evolution times can be used to construct an equivalent space to the Krylov state space used in the computation of the spread complexity. Afterwards, we introduce the effective dimension, which is upper-bounded by the number of pairwise distinct eigenvalues of the Hamiltonian. The computation of the spread complexity requires knowledge of the Hamiltonian and a classical computation of the different powers of the Hamiltonian. The computation of large powers of the Hamiltonian becomes increasingly difficult for large systems. The first part of our work addresses these issues by defining an equivalent space, where the original basis consists of quantum-mechanically measurable states. We demonstrate that a set of different time-evolved states can be used to construct a basis. We subsequently verify the results through numerical analysis, demonstrating that every time-evolved state can be reconstructed using the defined vector space. Based on this new space, we define an upper-bounded effective dimension and analyze its influence on finite-dimensional systems. We further show that the Krylov space dimension is equal to the number of pairwise distinct eigenvalues of the Hamiltonian, enabling a method to determine the number of eigenenergies the system has experimentally. Lastly, we compute the spread complexities of both basis representations and observe almost identical behavior, thus enabling the computation of spread complexities through measurements.

Hierarchical Equations of Motion for Quantum Chemical Dynamics: Recent Methodology Developments and Applications.

ConspectusQuantum effects are critical to understanding many chemical dynamical processes in condensed phases, where interactions between molecules and their environment are usually strong and non-Markovian. In this Account, we review recent progress from our group in development and application of the hierarchical equations of motion (HEOM) method, highlighting its ability to address some challenging problems in quantum chemical dynamics.In the HEOM method, the bath degrees of freedom are represented using effective modes from exponential decomposition of the bath correlation function. Complex spectral densities and low temperature simulations often require a larger number of modes, making the simulations very expensive. Recent advances, such as the barycentric spectral decomposition (BSD) technique, can significantly reduce the number of effective modes, allowing to handle complex spectral densities and enabling simulations at very low temperatures, including near-zero temperature dynamics.Another key improvement in the computational efficiency is the use of tensor network methods like matrix product states and hierarchical tensor networks. These techniques allow for efficient HEOM propagation with thousands of effective modes, crucial for simulating large molecular systems interacting with multiple baths. This combination enables simulations of excitation energy transfer (EET) in systems like the Fenna-Matthews-Olson (FMO) complex and even larger systems with experimentally determined spectral densities.The versatility of the HEOM method is demonstrated through applications to a wide range of chemical dynamics problems. Simulations of EET and related ultrafast spectroscopy are first briefly covered. Applications of the HEOM to quantum tunneling effects in proton transfer reactions are then presented. Early works have studied the non-Kramers dependence of the rate constant as a function of bath friction due to deep tunneling and revealed vibrationally nonadiabatic dynamics within the so-called nontraditional view of proton transfer reactions. A recent work on the large kinetic isotope effects in soybean lipoxygenase also indicated that many quantum correction approximations to classical transition-state theory may fall short in describing deep tunneling effects.Charge transport and separation dynamics in organic semiconductors are another area where the HEOM method has been instrumental. We first demonstrate that the HEOM provides a unified description of both band-like and thermally assisted charge carrier transport in organic materials. The effect of non-nearest neighbor transitions is then investigated by combining generalized master equations with exact memory kernels. The HEOM method also enables simulation of charge separation in organic photovoltaics (OPVs) and reveals how factors such as external electric fields, entropy, and charge delocalization influence the charge separation barrier and dynamics.Moreover, HEOM has been applied to investigate hydrogen atom scattering on the Au(111) surface and vibrational energy relaxation at molecule-metal interfaces. These studies provide deeper insights into how electron-hole pair excitations and temporary charge transfer states influence the nuclear motion, offering a new framework for simulating nonadiabatic dynamics on metal surfaces.In summary, the HEOM method has developed into a robust tool for simulating quantum effects in condensed phases. Future developments in algorithm efficiency and computational power will likely expand its applicability to even more complex systems.

EURAD state-of-the-art report: development and improvement of numerical methods and tools for modeling coupled processes in the field of nuclear waste disposal

The Strategic Research Agenda (SRA; https://www.ejp-eurad.eu/publications/eurad-sra) of the European Joint Programme on Radioactive Waste Management (EURAD; https://www.ejp-eurad.eu/) describes the scientific and technical domains and sub-domains and knowledge management needs of common interest between EURAD participant organizations. Theme number 7 is entitled “Performance assessment, safety case development and safety analyses.” A list of research and development priorities and activities of common interest to be addressed within EURAD for theme 7 have been established. Amongst others, the Understanding and modelling of multi-physical Thermo-Hydro-Mechanical-Chemical coupled processes (THMC) occurring in radioactive waste disposal is a major and permanent issue to support optimization of design and safety case abstraction. To tackle this challenge a research work package entitled “DONUT: Development and improvement of numerical methods and tools for modelling coupled processes” has been conducted within the EURAD join programming initiative. The purpose of this work package is to improve/develop methods or numerical tools in order to go a step further in development of (i) relevant, performant and cutting-edge numerical methods that can easily be implemented in existing or new tools, in order to carry out high-performance computing to facilitate the study of highly coupled processes in large systems, (ii) numerical scale transition schemes for coupled processes, (iii) innovative numerical methods to carry out uncertainty and sensitivity analyses. In this paper the work carried out within the DONUT work package is put in perspective regarding the existing concept and literature on the field. It does not pretend to be exhaustive but rather to put emphasis on particular issues tackled during the project.

Polarization-selective dual-band infrared metamaterial perfect absorber

Abstract Metamaterial absorbers have significant effects and great potential for applications in a variety of important sciences and technologies, including infrared imaging, thermal emitters, electromagnetic shielding, and photodetectors. However, conventional absorbers with a single function are difficult to meet the growing demand of devices, especially for the situations where the absorption and polarization are simultaneously required in infrared detection. If the polarization absorption function is realized by integrating absorption and polarization elements, it will lead to a large overall system size and slow response time. To solve this problem, we propose a dual-band polarization-selective metamaterial perfect absorber, whose maximum absorptions at resonant wavelengths of λ1=2.824μm and λ2=7.622μm are 99.99% and 99.88%, respectively. The absorber exhibits strong polarization sensitivity, absorbing TM-polarized incident light and reflecting TE-polarized incident light at the two resonant wavelengths. The extinction ratios of the absorber at the two referred resonant wavelengths are 90.9 and 142.7, respectively. The proposed absorber would be beneficial for infrared polarization detection and imaging.

Optimization of a large aperture wedge prism support system based on closed-loop Structural-Thermal-Optical Performance method

Optimization of a large aperture wedge prism support system based on closed-loop Structural-Thermal-Optical Performance method

Constraints of upper crust magmatic processes on the formation of Saindak porphyry Cu deposit: Insights from mineral geochemistry

Upper crustal magmatic processes play a crucial role in linking the magmatic and hydrothermal systems of porphyry deposits, ultimately controlling the generation of ore-forming fluids. Understanding these processes within a magma chamber is essential for deciphering the formation of porphyry deposits. The Saindak deposit, a large porphyry Cu system in the western Chagai belt, features coeval ore-forming and barren magma pulses, providing key insights into the characterization of porphyry systems. In this study, detailed petrographic observations and geochemical analyses of amphibole, plagioclase, and apatite were conducted to unravel the magmatic evolution at Saindak. Based on textural relationships and crystallization sequences, three distinct populations of amphibole in the ore-forming magma were identified. These amphiboles record the entire fractional crystallization process of magma that initially emplaced at a depth of ∼5 km to the connected magma system at ∼2 km. The study of amphibole and apatite reveals that the fertile magma underwent large-scale fluid exsolution in an open system. The simultaneous and rapid depletion of Cu, Cl, S, and H2O in the magma indicates that Cl and S were highly partitioned into the exsolved fluid phase. These elements formed complexes, which effectively concentrated metals in the fluid. Conversely, the barren magma was characterized by either low metal content or limited fluid exsolution within the magma chamber. Overall, we reconstruct the upper crustal magmatic processes at Saindak and conclude that efficient extraction of Cu through fluid exsolution is the key to porphyry deposit formation.

Operational long-term management of a salt cavern for industry targeted green H2 production

Hydrogen and its derivatives such as ammonia are increasingly important for reducing carbon emissions in sectors with limited alternatives. Large production systems are generally preferred to reduce costs and for those, advanced management is a cornerstone to the project economic viability. The present work explores the development of an Energy Management System for an industrial low-emission ammonia production platform. The latter is connected to the electrical grid and consists of 1.5 GW of renewable production units, around 500 MW of electrolyzers and storage facilities including especially a salt cavern for H2 storage. The long-term management of the salt cavern is decisive to enhance the profitability while satisfying industry related constraints such as the carbon content of the produced H2. The literature lacks in addressing both aspects simultaneously. Methodological approaches to tackle the long-term management and industrial constraints are proposed and compared. For the considered platform, it is shown that a strategy based on precalculated cost functions in the long term horizon allows relative gains of 2.5% with respect to a state-of-the-art short term management leading to an annual cost saving of approximately $6.2 million in the platform operational expenses. This translates to a reduction of the gap between the state-of-the-art and the optimal a posteriori solution by about 82%.

Novel optimal high pressure determination method for CO2 air source heat pump water heater: Experimental study and methodology development

As an efficient and environment-friendly solution to replace traditional fuel-fired boiler, CO2 air source heat pump water heater (HPWH) is widely used in the commercial and residential water heating. In order to achieve the optimal performance of CO2 air source HPWH systems, the effects of electronic expansion valve (EEV) opening and inlet water flow rate on system performance are experimentally studied and the optimal matching of the two parameters are obtained in this study. Then, the relationship between the optimal high pressure and the optimal matching of EEV opening and water flow rate is discussed. Finally, a new parameter, the endpoint temperature difference (ΔTep), is defined and a novel control strategy of ΔTep = 0 is proposed to determine the optimal high pressure. The results indicate that the optimal matching of EEV opening and water flow rate corresponds to the optimal high pressure and the best COPheat of system. A smaller ΔTep corresponding to a better matching degree and a larger system COPheat. The maximum deviation between the high pressure determined by the proposed new control strategy and the optimal high pressure is less than 1.8 %, and the system COPheat under the proposed new control strategy can achieve more than 97.6 % of the maximum COPheat. Therefore, the proposed control strategy in the paper is better than that of the commonly used off-line optimal high pressure correlation and can provide guidance for the efficient operation of the CO2 air source HPWH system.

Ancient Mythology in “La Princesse Maleine” by Maurice Maeterlinck: Intertextual Analysis

The article is devoted to the reconstitution of the mythological worldview of the well-known European Symbolist writer Maurice Maeterlinck based on his famous drama ‘Princess Maleine’ that made a great impact on the development of the ‘new drama’ in the end of the 19th century. This analysis is performed in the context of the study of the symbolist semiotic system in French-speaking tradition. The lingua-poetic and mythopoeic intertextual analysis done, we have found that the mythological model in the play is functioning with a large system of mythological structures and semantic patterns. The locus of ‘Princess Maleine’ is marked as Hades World and its inhabitants are connoting the mythical concept BAD LUCK. Only two actors, the protagonists Maleine and Hjalmar are connoted not only by the morbid semantics but also as the correlates of the astral world. Their death in Hades makes possible the eschatological catastrophe leading to the neutralization of the killers whereas the infernal semantics is neutralized and the cosmos tends to the restoring of harmony symbolized by the coming of the new day and of the new year. Besides, the protagonists are considered to be the sacred sacrifice to change the semantics of the mythological concept BAD LUCK to the harmonized GOOD LUCK. Three mythological models are reconstructed: LIFE with positive connotation, LIFE with negative connotation and DEATH with positive connotation. The projection of the play is modeled by the movement from the positively and negatively connoted concept LIFE to the positively connoted concept DEATH that is a distinctive sign of Symbolist conception of ‘tragic optimism’ developed by Maeterlinck.

Quantum Probabilistic Model Checking for Time-Bounded Properties

Probabilistic model checking (PMC) is a verification technique for analyzing the properties of probabilistic systems. However, existing techniques face challenges in verifying large systems with high accuracy. PMC struggles with state explosion, where the number of states grows exponentially with the size of the system, making large system verification infeasible. While statistical model checking (SMC) avoids PMC’s state explosion problem by using a simulation approach, it suffers from runtime explosion, requiring numerous samples for high accuracy. To address these limitations in verifying large systems with high accuracy, we present quantum probabilistic model checking (QPMC), the first method leveraging quantum computing for PMC with respect to time-bounded properties. QPMC addresses state explosion by encoding PMC problems into quantum circuits that superpose states within qubits. Additionally, QPMC resolves runtime explosion through Quantum Amplitude Estimation, efficiently estimating the probabilities of specified properties. We prove that QPMC correctly solves PMC problems and achieves a quadratic speedup in time complexity compared to SMC.

Recurrence resonance - noise-enhanced dynamics in recurrent neural networks

Understanding how neural networks process information is a fundamental challenge in neuroscience and artificial intelligence. A pivotal question in this context is how external stimuli, particularly noise, influence the dynamics and information flow within these networks. Traditionally, noise is perceived as a hindrance to information processing, introducing randomness and diminishing the fidelity of neural signals. However, distinguishing noise from structured input uncovers a paradoxical insight: under specific conditions, noise can actually enhance information processing. This intriguing possibility prompts a deeper investigation into the nuanced role of noise within neural networks. In specific motifs of three recurrently connected neurons with probabilistic response, the spontaneous information flux, defined as the mutual information between subsequent states, has been shown to increase by adding ongoing white noise of some optimal strength to each of the neurons. However, the precise conditions for and mechanisms of this phenomenon called ‘recurrence resonance’ (RR) remain largely unexplored. Using Boltzmann machines of different sizes and with various types of weight matrices, we show that RR can generally occur when a system has multiple dynamical attractors, but is trapped in one or a few of them. In probabilistic networks, the phenomenon is bound to a suitable observation time scale, as the system could autonomously access its entire attractor landscape even without the help of external noise, given enough time. Yet, even in large systems, where time scales for observing RR in the full network become too long, the resonance can still be detected in small subsets of neurons. Finally, we show that short noise pulses can be used to transfer recurrent neural networks, both probabilistic and deterministic, between their dynamical attractors. Our results are relevant to the fields of reservoir computing and neuroscience, where controlled noise may turn out a key factor for efficient information processing leading to more robust and adaptable systems.

Heparin treatment is associated with a delayed diagnosis of Alzheimer’s dementia in electronic health records from two large United States health systems

AbstractRecent studies suggest that heparan sulfate proteoglycans (HSPG) contribute to the predisposition to, protection from, and potential treatment and prevention of Alzheimer’s disease (AD). Here, we used electronic health records (EHR) from two different health systems to examine whether heparin therapy was associated with a delayed diagnosis of AD dementia. Longitudinal EHR data from 15,183 patients from the Mount Sinai Health System (MSHS) and 6207 patients from Columbia University Medical Center (CUMC) were used in separate survival analyses to compare those who did or did not receive heparin therapy, had a least 5 years of observation, were at least 65 years old by their last visit, and had subsequent diagnostic code or drug treatment evidence of possible AD dementia. Analyses controlled for age, sex, comorbidities, follow-up duration and number of inpatient visits. Heparin therapy was associated with significant delays in age of clinical diagnosis of AD dementia, including +1.0 years in the MSMS cohort (P &lt; 0.001) and +1.0 years in the CUMC cohort (P &lt; 0.001). While additional studies are needed, this study supports the potential roles of heparin-like drugs and HSPGs in the protection from and prevention of AD dementia.

Association between telehealth use in oncology and downstream utilization at a large academic health system.

While telemedicine has been beneficial in oncology by reducing infectious exposure and improving access for patients with poor functional status, it also has intrinsic limitations, including the inability to perform a physical exam, which could lead to increased downstream utilization in this population at high risk of medical decompensation. We conducted a retrospective cohort study investigating the relationship between telemedicine use in oncology and subsequent outpatient oncology encounters, emergency department (ED) visits, and hospitalizations. We included outpatient oncology encounters, including telemedicine and in-person visits, occurring between 1 January 2018 and 31 December 2022 at a large academic health system. Unadjusted descriptive statistics and multiple linear regressions were used to estimate subsequent outpatient oncology visits, ED visits, and hospitalizations within 30 days of an index visit based on modality (telemedicine versus in-person). The multiple regressions were adjusted for various demographic and clinical characteristics, including palliative care visits, baseline utilization, recent chemotherapy, and comorbidities. Our cohort included 63,722 patients with 689,356 outpatient encounters, of which 639,217 (92.7%) were in-person and 50,139 (7.3%) were telemedicine visits. Patients on average had 0.91 outpatient oncology visits, 0.04 ED visits, and 0.05 hospitalizations within 30 days following an index encounter. In our adjusted analyses, telemedicine was associated with 13.7 fewer downstream outpatient oncology visits (95% CI 12.5-14.9; p < 0.001) per 100 index encounters, 0.7 fewer ED visits (95% CI 0.4-1.0; p < 0.001) per 100 index encounters and 0.9 fewer hospitalizations (95% CI 0.6-1.3; p < 0.001) per 100 index encounters compared to in-person visits. Contrary to our hypothesis, oncology patients who had a telemedicine visit had fewer follow-up outpatient oncology encounters, ED visits and hospitalizations after 30 days than those with in-person visits. Future studies should further investigate the efficacy of telemedicine in oncology and outline specific scenarios for appropriate use in this and other populations.

Anomalous Non-Hermitian Open-Boundary Spectrum.

For a long time, it was presumed that continuum bands could be readily encompassed by open-boundary spectra, irrespective of the system's modest dimensions. However, our findings reveal a nuanced picture: under open-boundary conditions, the proliferation of complex eigenvalues progresses in a sluggish, oscillating manner as the system expands. Consequently, even in larger systems, the overlap between continuum bands and open-boundary eigenvalues becomes elusive, with the surprising twist that the count of these complex eigenvalues may actually diminish with increasing system size. This counterintuitive trend underscores that the pursuit of an ideal, infinite-sized system scenario does not necessarily align with enlarging the system size. Notably, despite the inherent non-Hermiticity of our system, the eigenstates distribute themselves in a manner reminiscent of Bloch waves. These discoveries hold potential significance for both theoretical explorations and experimental realizations of non-Hermitian systems.

Electrostatically embedded symmetry-adapted perturbation theory.

Symmetry-adapted perturbation theory (SAPT) is an abinitio approach that directly computes noncovalent interaction energies in terms of electrostatics, exchange repulsion, induction/polarization, and London dispersion components. Due to its high computational scaling, routine applications of even the lowest order of SAPT are typically limited to a few hundred atoms. To address this limitation, we report here the addition of electrostatic embedding to the SAPT (EE-SAPT) and ISAPT (EE-ISAPT) methods. We illustrate the embedding scheme using water trimer as a prototype example. Then, we show that EE-SAPT/EE-ISAPT can be applied for efficiently and accurately computing noncovalent interactions in large systems, including solvated dimers and protein-ligand systems. In the latter application, particular care must be taken to properly handle the quantum mechanics/molecular mechanics boundary when it cuts covalent bonds. We investigate various schemes for handling charges near this boundary and demonstrate which are most effective in the context of charge-embedded SAPT.

DietNerd: A Nutrition Question-Answering System That Summarizes and Evaluates Peer-Reviewed Scientific Articles

DietNerd is a large language model-based system designed to enhance public health education in diet and nutrition. The system responds to user questions with concise, evidence-based summaries and assesses the quality and potential biases of cited research. This paper describes the system’s workflow, back-end implementation, and the prompts used. Accuracy and quality-of-response results are presented based on an automated comparison against systematic surveys and against the responses of similar state-of-the-art systems through human feedback from registered dietitians. DietNerd is among the highest-evaluated of these systems and is unique in combining safety features with sophisticated source analysis. Thus, DietNerd could be a tool to bridge the gap between complex scientific literature and public understanding.

8263 Long-term Imaging Follow-up of Non-functioning Pituitary Adenomas

Abstract Disclosure: N. Mehrotra: None. M.M. Ross: None. A.S. Chilukuri: None. S. Eljamri: None. C. Ewing: None. S. Patel: None. V. Patel: None. L.B. Siegel: None. D. Sistla: None. R.K. Shariff: None. P.K. Fazeli: None. Pituitary adenomas are common, affecting ∼15% of the population. Once a pituitary adenoma has been identified on imaging, an evaluation is undertaken for pituitary hormone excess and for pituitary hormone deficiency in the setting of larger adenomas (typically 1cm in size or greater). Hormone-producing or functioning pituitary adenomas are typically treated with medical or surgical therapy, but non-functioning pituitary adenomas can be followed conservatively if they are not contributing to morbidity. The natural history of non-functioning pituitary adenomas has not been well characterized and therefore although guidelines recommend follow-up pituitary imaging, there are no specific guidelines addressing how frequently or for how long these lesions should be followed. Our aim was to describe the clinical history of non-functioning pituitary adenomas using long-term clinical data from a large academic health system. We identified 791 patients who met our inclusion criteria of having more than one brain/pituitary MRI performed at least 3 months apart with a suspected non-functioning adenoma identified on the initial MRI. Each medical record was individually reviewed to confirm whether the adenoma was non-functioning based on clinical/biochemical evaluation. Patients were a median [interquartile range] of 48.3 [34.4, 63.6] years of age at the time of first MRI and 65% (n=517) were women. At presentation, 66% (n=523) of the pituitary adenomas were microadenomas (&amp;lt; 1 cm in size) and 34% were macroadenomas (&amp;gt; 1 cm). All patients had an MRI repeated at least 3 months after the initial MRI with median time of total imaging follow-up of 39.8 [17.0, 75.6] months. During follow-up, 658 patients were noted to have a stable lesion or a decrease in size of the adenoma. Patients whose lesion was noted to grow on MRI were slightly older than those who did not have growth (growth: 57.1 [41.9, 70.3] years versus no growth: 46.8 [33.7, 62.3] years, p&amp;lt; 0.0001). There were no differences with respect to BMI, hypopituitarism, smoking history or alcohol use between those with growth versus those without growth. Seventy-eight patients (9.9%) had surgical resection of their adenoma during follow-up. The most common indication for surgery was growth of the lesion (n=27), followed by visual changes (n=22). In the patients with a microadenoma at presentation, 90.8% remained stable in size or decreased in size during a median follow-up of 43.2 [20.5, 78.6] months. Only 2.3% of patients with a microadenoma at presentation underwent surgical resection during follow-up. In conclusion, the majority of non-functioning pituitary adenomas remain stable during prolonged imaging follow-up. Further study is needed to determine predictors of growth of non-functioning pituitary adenomas. Presentation: 6/2/2024