Good Resolution Research Articles

OPTIMIZATION OF EXPOSURE FACTORS WITH VARIATION OF FILTER THICKNESS ON DOSE VALUES AND RADIOGRAPHIC IMAGE QUALITY IN PELVIS EXAMINATION

This study examines the impact of varying X-ray tube voltage (kV) and filter thickness on patient radiation dose and image quality in radiographic procedures. It aims to optimize exposure factors to minimize patient dose while maintaining diagnostic image quality, contributing to safer and more efficient radiological practices. This quantitative experimental study investigates the impact of varying filter thickness and tube voltage on patient radiation dose. Using X-ray equipment, dosimeters, and phantoms, measurements of Incident Air Kerma (INAK) and Entrance Surface Air Kerma (ESAK) and effective dose are taken, followed by image quality assessments to optimize exposure factors while maintaining diagnostic efficacy. The study demonstrated that increasing filter thickness decreases both INAK and ESAK values, with the most significant dose reduction occurring at 2 mm thickness. Optimal image quality and effective dose reduction were observed with the 1 mm filter at 80 kV, reducing the dose by 14.3% to 20% while maintaining good spatial resolution and contrast. The study concludes that using a 1 mm aluminum filter with 80 kV significantly reduces the effective dose while maintaining image quality. It is recommended that hospitals adopt additional filters, conduct further research with different materials, and optimize exposure factors. Training for radiology technicians on these practices is essential to enhance patient safety and image quality. Keywords: X-ray Equipment, Entrance Surface Air Kerma, Effective Dose, Image Quality.

Deformations of some local Calabi-Yau manifolds

We study deformations of certain crepant resolutions of isolated rational Gorenstein singularities. After a general discussion of the deformation theory, we specialize to dimension $3$ and consider examples which are good (log) resolutions as well as the case of small resolutions. We obtain some partial results on the classification of canonical threefold singularities that admit good crepant resolutions. Finally, we study a noncrepant example, the blowup of a small resolution whose exceptional set is a smooth curve.

ITSxpress version 2: software to rapidly trim internal transcribed spacer sequences with quality scores for amplicon sequencing.

The nuclear ribosomal RNA (rRNA) internal transcribed spacer (ITS) regions are commonly used to identify fungi and other eukaryotic taxa in amplicon sequencing. The highly conserved rRNA regions flanking the ITS are often trimmed before being used for taxonomic assignment. The Python software package ITSxpress rapidly trims single-end or paired-end sequences in FASTQ format for use in amplicon sequence variant clustering methods like DADA2. This new major release of ITSxpress improves the paired-end merging method, simplifies installation of the QIIME 2 ITSxpress plugin, removes major dependencies, adds use cases, and is compatible with newer compression formats. This article discusses the modifications to ITSxpress that improve the output and user experience, leading to a major version increase.IMPORTANCEITSxpress is a sequence trimming method applied to internal transcribed spacer (ITS) amplicon sequences before calling amplicon sequence variants (ASVs). The ITS region is used to understand the composition of eukaryotic microbial communities. ITS sequences provide good taxonomic resolution due to their hypervariability, but are flanked by conserved regions that allow their primers to be more universal. Amplicons generated with such primers contain regions with different evolutionary rates, and trimming these conserved regions results in better taxonomic classification and a more valid set of ASVs. This package can be used for most amplicon sequencing methods including for newer long-read sequencing formats, such as PacBio. ITSxpress can be installed from Bioconda, used as a Docker image, or installed from source code. The package works well with high-performance computing clusters or laptops due to its low-resource requirements.

Spatial variability of hydraulic parameters of a cropped soil using horizontal crosshole ground penetrating radar

AbstractSoil hydraulic parameters (SHP) play a crucial role controlling the spatiotemporal distribution of water in the soil–plant continuum and thus affect water availability for crops. To provide reliable information on the SHP at different scales, measurement techniques with a good spatial resolution and low labor costs are required. In this study, we used crosshole ground penetrating radar (GPR)‐derived soil water contents (SWCs) measured along horizontal rhizotubes under a controlled experimental test site cropped with winter wheat to estimate the unimodal and dual‐porosity soil hydraulic characteristics with different soil layer setups. Therefore, sequential inversion of the GPR‐derived SWCs was performed using the hydrological model HYDRUS‐1D, whereby the SWC data were either averaged prior inversion or used in a spatially distributed way. To analyze if the time‐lapse gathered GPR data contain enough information to estimate the SHP, additional synthetic studies were performed increasing the data resolution to daily GPR measurements. The results showed that the time‐lapse data contained enough information to estimate the SHP accurately. Additionally, spatially distributed soil hydraulic characteristics differed from the one estimated based on averaged SWCs derived from spatially distributed GPR data. Finally, we derived spatially resolved SHP, which can be used for 3D process rhizosphere processes and root–soil interaction modeling.

Prospection of faults on the Southern Erftscholle (Germany) with individually and jointly inverted refraction seismics and electrical resistivity tomography

As part of the Lower Rhein Embayment (LRE), the Southern Erft block is characterized by a complex tectonic setting that influences hydrological and geological conditions on a local as well as regional level. The study area is located in the south of North Rhine-Westphalia and traversed by several NW-SE-oriented fault structures. Since the tectonic structures were located by past studies based on a sparse foundation of geological data, the positions include considerable uncertainties. Therefore, it was decided to re-evaluate and refine the assumed fault locations by conducting geophysical measurements. Seismic Refraction Tomography (SRT) as well as Electrical Resistivity Tomography (ERT) was performed along seven measurement profiles with a length of up to 1.1 km. In addition to compiling individual resistivity and velocity models for all deduced measurements, ERT and SRT datasets were cooperatively inverted using the Structurally Coupled Cooperative Inversion (SCCI). This algorithm strengthens structural similarities between velocity and resistivity by adapting the individual regularizations after each model iteration. Previously assumed locations of the tectonic structures diverge from the new evidence based on ERT and SRT surveys. Especially in the western and eastern parts of the research area, differences between the survey results and formerly assumed locations are in the order of 100 m. Seismic and geoelectric measurements further indicate a fault structure in the southern part of the area, which remained undetected by past studies. The cooperative inversions do not improve the geophysical models qualitatively, since the individually inverted datasets already provide results of good quality and resolution.

Mitigation of DMM-induced stripe patterns in synchrotron X-ray radiography through dynamic tilting.

In synchrotron X-ray radiography, achieving high image resolution and an optimal signal-to-noise ratio (SNR) is crucial for the subsequent accurate image analysis. Traditional methods often struggle to balance these two parameters, especially in situ applications where rapid data acquisition is essential to capture specific dynamic processes. For quantitative image data analysis, using monochromatic X-rays is essential. A double multilayer monochromator (DMM) is successfully used for this aim at the BAMline, BESSY II (Helmholtz Zentrum Berlin, Germany). However, such DMMs are prone to producing an unstable horizontal stripe pattern. Such an unstable pattern renders proper signal normalization difficult and thereby causes a reduction of the SNR. We introduce a novel approach to enhance SNR while preserving resolution: dynamic tilting of the DMM. By adjusting the orientation of the DMM during the acquisition of radiographic projections, we optimize the X-ray imaging quality, thereby enhancing the SNR. The corresponding shift of the projection during this movement is corrected in post-processing. The latter correction allows a good resolution to be preserved. This dynamic tilting technique enables the homogenization of the beam profile and thereby effectively reduces noise while maintaining high resolution. We demonstrate that data captured using this proposed technique can be seamlessly integrated into the existing radiographic data workflow, as it does not need hardware modifications to classical X-ray imaging beamline setups. This facilitates further image analysis and processing using established methods.

A new method development and validation for simultaneous estimation of ramipril and telmisartan by RP-HPLC method in combined dosage form

The present research work was development and validation of new RP-HPLC method for simultaneous estimation of Ramipril and Telmisartan in combined dosage form. In simultaneous RP-HPLC method development, Waters 2695 Separations Module with PDA Detector and column used is C8 SB ZORBAX (150 X 4.6mm) column with 3.5-micron particle size. Injection volume of 10 µL is injected and eluted with the mobile phase selected after optimization was Phosphate buffer and Acetonitrile in the ratio of 70:30 was found to be ideal. The optimized flow rate was at 1.0 mL/min. Detection was carried out at 230 nm. This system produced symmetric peak shape, good resolution and reasonable retention times of Ramipril and Telmisartan were found to be 2.275 and 4.261 minutes respectively. The Ramipril and Telmisartan showed linearity in the range of 20-60 µg/mL and 160-480 µg/mL respectively. The %RSD values for precision was found to be within the acceptable limit, which revealed that the developed method was precise. The developed method was found to be robust and the %RSD value for percentage recovery of Ramipril and Telmisartan was found to be within the acceptance criteria. The results indicate satisfactory accuracy of method for simultaneous estimation of the Ramipril and Telmisartan.

Biocompatible PVAc-g-PLLA Acrylate Polymers for DLP 3D Printing with Tunable Mechanical Properties.

The technological advancement of Additive Manufacturing has enabled the fabrication of various customized artifacts and devices, which has prompted a huge demand for multimaterials that can cater to stringent mechanical, chemical, and other functional property requirements. Photocurable formulations that are widely used for Digital Light Processing (DLP)/Stereolithography (SLA) 3D printing applications are now expected to meet these new challenges of hard and soft or stretchable structural requirements in addition to good resolution in multiple scales. Here we present a biocompatible photocurable resin formulation with tunable mechanical properties that can produce hard or stretchable elastomeric 3D printed materials in a graded manner. Acrylate poly(lactic acid) (PLA) grafted polyvinyl acetate (PVAc) polymer was mixed with hydroxyl ethyl methacrylate (HEMA) and hydroxyl ethyl acrylate (HEA) as reactive diluents (50-70 wt %) in various compositions to form a series of photocurable resin formulations. Depending on the nature of the reactive diluent (HEMA or HEA) and their weight percentage, the mechanical properties of the 3D printed parts could be fine-tuned from hard (Tensile strength 20.6 ± 2 MPa, elongation 2 ± 1%) to soft (Tensile strength 1.1 ± 0.2 MPa, elongation 62 ± 8%) materials. The printed materials displayed remarkable dye absorption (95%), showing stimuli-responsive behavior for dye release (with respect to both pH and enzyme), while also demonstrating high cell viability (>90%) for mouse embryonic (WT-MEF) cells and degradability in PBS solution. These biobased 3D printing resins have the potential for a variety of applications, including tissue engineering, soft robotics, dye absorption, and elastomeric actuators.

Concurrent Estimation of Pregabalin and Etoricoxib by New Stability-Indicating RP-UPLC Approach - Application in Assay of Commercial Tablets

Background: The study emphasizes establishing a stability-indicating RP-UPLC method for concurrent estimation of pregabalin and etoricoxib in combined pharmaceutical formulations, confirming effective separation, sensitivity, and repeatability, validated according to ICH guidelines. Objective: The present research study aims to establish a new stability-indicating RP-UPLC method for concurrently estimating pregabalin and etoricoxib in blended powder and their combined tablet formulation with less run time, high sensitivity, and specificity. Methods: The effective separation of pregabalin and etoricoxib was achieved with HSS column C18 (150x2.1mm,1.8μm), 0.1% orthophosphoric acid:acetonitrile (65:35 v/v) at a flow rate of 0.3mL/min, and isocratic elution at 228nm. The elution of PRB and ETB was noticed at 1.56 and 2.01 minutes, with good resolution and system suitability with the developed approach. Results: Pregabalin and etoricoxib have shown linear responses from 18.75 to 112.5μg/mL and 15 to 90μg/mL, respectively. The range of the % RSD for intraday and inter-day precision was 0.33 to 0.81. The LOD and LOQ of pregabalin and etoricoxib were computed to be 0.07 μg/mL and 0.21 μg/mL, and 0.01μg/mL and 0.04 μg/mL, respectively, by standard deviation method. The validation method was carried out using ICH standards. The stability-indicating feature of the method was confirmed by the forced degradation studies where degradants generated by stress testing were clearly distinguished from the peaks of analytes. Conclusion: The shorter elution period and superior sensitivity of both analytes with this method have been found to be appropriate for regular analysis of pregabalin and etoricoxib.

A Consistent and Well‐Balanced Hybrid Weighted Essentially Non‐Oscillatory Scheme for Shallow Water Equations on Unstructured Meshes

ABSTRACTIn this article, a type of high‐order consistent and well‐balanced hybrid weighted essentially non‐oscillatory (WENO) scheme is proposed for shallow water equations with flat or non‐flat bottom on unstructured triangular meshes. The hybrid scheme presents a new consistent discretization format on the flux and the source term with the goal of obtaining a hybridization of the high‐order WENO scheme and linear scheme. According to the modified multi‐resolution analysis approach, we can select the more robust and accurate WENO reconstruction in the vicinity of discontinuities, and the less expensive linear reconstruction in the smooth regions. As a result, the suggested hybrid WENO scheme can acquire the capacity of saving the computing time cost while maintaining the excellent numerical features of the original WENO scheme. Eventually, some extensive and classical two‐dimensional numerical examples, including a tidal bore of an estuary with an irregular computation area are provided to validate the performance of this hybrid WENO scheme on triangular meshes in terms of accuracy order, exact conservation property, shock‐capturing, good resolution, and computational efficiency.

Non-invasive characterization of the manufacturing process of a Nuragic bronze statuette: a Neutron Imaging study

The Nuragic civilization (Sardinia, Italy, XVIII–VIII Cen. B.C) developed a flourishing bronze metallurgy. The production of Nuragic bronze figurines from Sardinia represents a rich historical archive that provides key information about the iconography, the metal production and casting techniques, and on the development of metallurgy in the Mediterranean basin. Since the question about their manufacturing method remains without definitive answer, the understanding of the Sardinian bronze metallurgy is essential to determine which manufacturing techniques were employed to produce complex bronze artefacts. In the frame of a wider research project relating to Nuragic bronzes, four artefacts, three anthropomorphic statuettes (a warrior, a priestess, and an offering figure), and one miniature of a basket, were made available by Museo Nazionale Preistorico “L. Pigorini” (Roma, IT). In this work we present the results of the analyses conducted on a bronze figurine depicting an iconic type of Nuragic figure: the Priestess. The analysis was performed using White Beam Neutron Tomography (NT) and Bragg Edge Neutron Transmission (BENT) at the Paul Scherrer Institut (PSI) (Villigen, CH). Neutron techniques are nowadays the only available approach for revealing, non-destructively and with good spatial resolution, the morphological and microstructural properties within the whole volume of solid cast metallic artefacts such as this bronze statuette. This work presents the result of a non-invasive analytical investigation on an archaeological bronze artefact, providing outstanding results: from a quantitative analysis of the composition to an in-depth morphological and microstructural analysis capable of unveiling details on the ancient casting methods of the statuette.

LPI radar waveform design based on complementary phase and discrete chaotic frequency joint coding

In order to reduce the probability of radar radiation signals being detected by enemy passive detection systems, this paper proposes a phase and frequency joint coding low intercept Radar waveform design method. Based on the linear frequency modulation signal, this method uses complementary binary code and chaotic sequence to phase encode the intra-pulse modulation. Code and frequency coding. The numerical simulation results show that the designed waveform exhibits pseudo-random characteristics in the time-frequency domain, and the low recognition performance is improved; The signal has an extremely low peak sidelobe level after matched filtering, showing excellent low intercept performance; its three-dimensional ambiguity function diagram presents an ideal “graph”. Fishing type”, with good distance, speed resolution and anti-interference characteristics.

Research on power metering method for nonlinear loads in power system based on improved S-transform

Abstract Traditional power metering algorithms are no longer suitable for new power systems to address the issue of distorted voltage and current waveforms caused by a growing number of nonlinear loads in modern power systems. The paper proposes a power-metering algorithm based on an Improved Stockwell Transform (IST). Based on the Stockwell transform, several parameters that can control the Gaussian window are introduced to improve the flexibility of the Gaussian window. Additionally, the inequality constraint based on the energy concentration measure is used to optimally select the best window parameters, enhancing the time–frequency domain analysis capability of the IST. The study uses IST to decompose and reconstruct the voltage and current fundamental characteristic signals and distortion characteristic signals in the power system. This provides good time resolution at low frequencies and good frequency-domain resolution at high frequencies. Power metering based on unsteady voltage and current is achieved by calculating the resulting fundamental and harmonic powers, respectively. The simulation results demonstrate that the IST-based power metering method has a higher level of accuracy than the existing metering methods.

ZGSO:Cr3+,Ni2+ Persistent Phosphors with Dual Emission in NIR-I and SWIR Ranges for Bio-Imaging Applications.

Persistent luminescence (PersL) is widely used for near infrared (NIR-I, 650-950nm) imaging as they allow getting images without background. Bio-imaging in the second shortwave-infrared region SWIR-II (NIR-II, 1000-1400nm) is less widespread but is growing as it offers the advantages of low photon scattering, increased in vivo penetration depth, and improved imaging clarity. In this work, the preparation and the complete optical properties of a new material is reported, Zn1.33Ga1.33Ni0.005Cr0.005Sn0.33O3.995 (ZGSO:Cr3+, Ni2+) able of emitting in both deep-red/NIR-I and SWIR (NIR-II) and shows its potential in bioimaging. ZGSO:Cr3+, Ni2+ can be excited using different sources such as X-rays, UV, and visible light to emit persistent signals in dual biological windows (dual-BW). By integrating an energy transfer process from Cr3+ to Ni2+ within this newly synthesized material, the influence of co-dopants on signal intensity and emission wavelengths is sought to explore. PersL at ≈700nm (NIR-I) and ≈1300nm (NIR-II) have been tested in preliminary bioimaging experiments using different protocols, allowing signal detection with good spatial resolution and depth sensitivity. The dual-BW PersL imaging strategy expands the toolbox for highly accurate analysis and has, for the first time, allowed access to accurately high-resolution sensing, and tracing.

Development of a multi-layer high-efficiency GEM-based neutron detector for spallation sources

Neutron detection is nowadays mostly based on 3He gas detectors, but its shortage and the continuous upgrades of the neutron facilities require new devices to perform experiments with maximum performances. This work presents a new detector based on the Gas Electron Multiplier (GEM) combined with several boron layers. This detector combines the features of GEM technology with the properties of boron as a neutron converter and the device is produced to sustain high neutron fluxes with high detection efficiency. The detector has been characterised at the ISIS Pulsed Neutron and Muon Source (UK). Based on the analysis of our results, the detector has shown a good response to thermal and epithermal neutrons reaching a detection efficiency of 16% at 1.8 Å (25 meV). The good detection efficiency (even increasable with the addition of further boron GEM foils) and the good time resolution, make the detector a unique device for the neutron techniques. In particular, its use can easily be envisaged in techniques involving neutron transmission measurements, that require high fluxes impinging on the detectors, with the added bonus of a 2D-resolved capability due to the padded anode.

Enhanced Timing Performance of Dual-Ended PET Detectors for Brain Imaging Using Dual-Finishing Crystal Approach.

This study presents a novel approach to enhancing the timing performance of dual-ended positron emission tomography (PET) detectors for brain imaging by employing a dual-finishing crystal method. The proposed method integrates both polished and unpolished surfaces within the scintillation crystal block to optimize time-of-flight (TOF) and depth-of-interaction (DOI) resolutions. A dual-finishing detector was constructed using an 8 × 8 LGSO array with a 2 mm pitch, and its performance was compared against fully polished and unpolished crystal blocks. The results indicate that the dual-finishing method significantly improves the timing resolution while maintaining good energy and DOI resolutions. Specifically, the timing resolution achieved with the dual-finishing block was superior, measuring 192.0 ± 12.8 ps, compared to 206.3 ± 9.4 ps and 234.8 ± 17.9 ps for polished and unpolished blocks, respectively. This improvement in timing is crucial for high-performance PET systems, particularly in brain imaging applications where high sensitivity and spatial resolution are paramount.

Fabrication and testing of a 3D double-stack RPC with 30 gas gaps for detection of high energy gammas

Multigap Resistive Plate Chambers (MRPCs) are cost-effective detectors with a high-performance. They are easy to build and offer the possibility to cover large areas. They provide excellent time resolution and potentially good spatial resolution. In this context, a 3D RPC with 15 double-stack layers (30 gas gaps) free of parallax error is fabricated. The designed RPC has a 2D pixelated readout and the induced charge on the ground electrodes, gives the position in the third dimension. The simulation results show that in the X–Y plane the Full Width Half Maximum (FWHM) resolution is around 70 μm for 511 keV gammas, while for the Z-axis, which is perpendicular to the detector plane, a spatial resolution of around 560 μm can be achieved. The fill factor of the proposed detector with a pitch of 6.25 mm for SNR of 17 is around 0.13%, and the maximum achievable fill factor for the same setup and SNR of 42.5 is around 23%. The measured spatial resolution of the detector for a collimated Cs-137 point source is in good agreement with the simulation results. For an isotropic 511 keV gamma source at 0.95 cm distance of RPC detector, the experimental detection efficiency of constructed RPC at 1900V applied voltage is around 2.1%, which with a relative error of 7% is in good agreement with the simulation result obtained by GEANT4 (2.25%). With the same detector, at larger distances of the gamma source from the detector (clinical PET camera) a detection efficiency of around 5.09% is achievable. For small animal PET (100 mm radius) with 18F point source, the spatial resolution (Γ) of a PET system composed by 3D MRPC detectors with 2.25∗2.25 mm2 and 1∗1 mm2 pixel sizes, fabricated by commercial PCB technology (pitch = 6.25 mm) and Microlithography technology (pitch = 1.25 mm), would be 1.64 mm and 0.91 mm, respectively.

Determining the carbon detection limit with magnetic sector dynamic secondary ion mass spectrometry (SIMS)

Dynamic SIMS is often used to evaluate the concentration of impurities in solids because of its high sensitivity, depth profiling capabilities, good depth resolution, and high throughput. Continuous ion beam sputtering with a high-density primary beam provides high sensitivity and reduces the background contribution from residual gases within the analytical chamber. Dynamic SIMS experiments performed with several magnetic sector instruments using various sputtering rate conditions demonstrated a slow decrease of the carbon detection limit with the increase of sputtering rate (SR), when it was varied by changing the sputtering beam density. The dependence data, within the scatter limits, can be fit by a power function of SR with the exponent of about −1/2. The observed detection-limit-dependence curve is common for magnetic sector SIMS instruments, owing to contamination and the design of the analytical chamber. The depth resolution of light-element SIMS analysis (except for oxygen) performed using Cs+ sputtering is limited and cannot be improved by reducing the impact energy of the sputtering beam. A segregation-type depth profile with a long trailing edge was observed in the B, C, and N depth profiles when Cs+ sputtering was employed under ultra-high vacuum conditions. This effect is plausibly associated with preferential sputtering owing to the difference in the surface binding energy, along with the large difference in the mass of the interacting atoms within the collision cascade during sputtering. The depth resolution improved with surface oxidation when Cs + sputtering was combined with backfilling of the analytical chamber using O2. The analytical chamber backfilled with oxygen can be sufficiently replaced with a very low-impact energy-focused oxygen beam, enabling simultaneous oxygen and cesium co-sputtering SIMS analysis. The practical feasibility of using a co-sputtering with focused Cs+ and O2+ sputtering beams to achieve a high depth-resolution for carbon analysis under ultrahigh vacuum conditions was demonstrated.

Organic probes for three‐photon fluorescence imaging in NIR‐II window: Design, applications, and perspectives

AbstractThree‐photon fluorescence (3PF) imaging is an emerging technology for imaging deep‐tissue submicroscopic structures by nonlinearly redshifting the excitation wavelength to the second near‐infrared (NIR‐II) window; thus, this approach has great advantages, including deep penetration depth, good spatial resolution, low background, and a high signal‐to‐noise ratio. 3PF imaging has been demonstrated to be a powerful tool for noninvasively visualizing all kinds of deep tissues in recent years. Benefiting from excellent biosecurity and structural controllability, the development of organic 3PF probes is highly important for advancing 3PF imaging in vivo. However, there is no summary of the generalizability of the design and recent progress in organic 3PF probes. Herein, this review introduces the fundamental principle of 3PF imaging and highlights the advantages of 3PF bioimaging. The molecular design of these organic 3PF probes is also summarized based on relative optical indices. Furthermore, different 3PF imaging application scenarios are listed in detail. In the end, the main challenges, significance of probe exploitation, and prospective orientation of organic probes for precise 3PF imaging are proposed and discussed for promoting future applications and clinical translation.

7418 Xanthoma Disseminatum - A Rare cause of Diabetes Insipidus

Abstract Disclosure: P. Balasubramanian: None. J. Cohen: None. Z. Corbin: None. G. Panse: None. S.E. Inzucchi: None. Background: Xanthoma disseminatum is a rare non-Langerhans cell-derived benign histiocytosis of unknown etiology, characterized by mucocutaneous xanthomatosis. Systemic involvement occurs in a subset of patients, the most common manifestation being central diabetes insipidus in the setting of hypothalamic-pituitary- infundibulum infiltration, occurring in about 30-50% of the patients. We present the case of a man with biopsy proven cutaneous xanthoma disseminatum who developed central diabetes insipidus due to pituitary stalk involvement. Case Presentation: A 69-year-old male presented with a 2-year history of symmetrically distributed, erythematous to hyperpigmented macules and papules in the axillae and inguinal folds. He did not have any mucosal lesions. Skin biopsy revealed histiocytic infiltrate consistent with non-Langerhans cell histiocytosis, likely xanthoma disseminatum. He developed symptoms of polyuria and nocturia around the same time of the eruption, resulting in a large daily fluid intake of 100-120 ounces/day for several months. Laboratory evaluation revealed normal electrolytes. After an overnight water deprivation test, serum osmolality was 299mOsm/kg, serum sodium was 144mmol/L and urine osmolality was 280mOsm/kg, consistent with partial central diabetes insipidus. MRI pituitary with and without IV contrast showed thickening and hyperenhancement of the pituitary stalk. Anterior pituitary function was intact except for mild hypogonadotropic hypogonadism. He was started on DDAVP with good response and resolution of symptoms. Conclusion: Xanthoma disseminatum is characterized by extensive mucocutaneous xanthomatosis with occasional systemic involvement. The natural history of xanthoma disseminatum is usually benign, indolent, and slowly progressive with spontaneous regression described in a few cases. Hypothalamic and pituitary involvement may cause hyperprolactinemia, central diabetes insipidus, and variable degrees of hypopituitarism. Diabetes insipidus is often mild and sometimes transient. Occasionally, central diabetes insipidus can precede the skin lesions. Prognosis is generally good. Central nervous system involvement outside the hypothalamus/pituitary carries a poor prognosis. Presentation: 6/2/2024