Large Mass Research Articles

Spectrum of imaging findings of primary bone lymphoma in pediatric patients.

Primary bone lymphoma, a rare oncologic entity, may initially present with minimal symptoms. Presenting symptoms range from local pain and mild systemic symptoms to large palpable masses and pathologic fractures. The term "primary bone lymphoma" indicates the finding of bone involvement without other organ sites for at least 6months. Although some radiological features may raise suspicion about this tumor form, there are no pathognomonic imaging findings, and the diagnosis will likely be delayed for a long time. The most critical radiological feature is soft tissue involvement associated with a preserved cortical layer, much more than expected for an infiltrating lesion. Anyway, very different radiological findings may be displayed in patients with primary bone lymphoma. Although these radiological features of primary bone lymphoma have been discussed in the literature by various authors, there is little data concerning imaging in pediatric patients. This paper aims to depict the possible spectrum of imaging features of primary bone lymphoma in the pediatric age, providing an exemplification pictorial essay extracted from a single institution experience in the year range period 2006-2022.

MAKEOVER FORMAT PROGRAMS ANALYSIS OF DISCOURSES ON BODY MODIFICATION

The body is an important means of communication and has been interpreted in various ways by different disciplines from past to present. With the various symbolic meanings attributed to the body, it has undergone changes throughout history and has affected culture and society in this process. Body modification refers to a change within the framework of the beauty ideal and has gained an importance that will affect large masses today, shaped by dynamics such as nature, tradition, beliefs, politics, power, ideology, industrialization, globalization, fashion, consumption, technology and medicine. Mass media, and especially television, influence the masses with the discourses they produce on body modification. Through the makeover format, which is one of the reality show program types, it directs especially women to the act of consumption and encourages modification in order to achieve ideal beauty.

Presentation of a Locally Advanced Cervical Cancer with Hydrometrocolpos: A Case Report

Introduction: Early stages of cervical cancer remain asymptomatic. Its common symptoms are postcoital bleeding, postmenopausal bleeding, heavy menstrual flow and foul smelling blood stained discharge. Presentation of locally advanced cervical cancer with hydrometrocolpos is unusual. Case report: An 83-year-old woman who presented with a large abdomino-pelvic mass was diagnosed as benign bilateral ovarian tumour with left sided hydroureteronephrosis. During laparotomy, the mass was confirmed to be a hydrometrocolpos with left hydroureteronephrosis secondary to a locally advanced cervical cancer (FIGO IIIB). Histology confirmed the diagnosis of invasive squamous cell carcinoma of the cervix. Conclusion: Besides thorough evaluation via symptoms and signs, radiologists have an important role in guiding surgeons to the most probable diagnosis. In an elderly woman with a stenosed vagina and a pelvic mass with hydroureteronephrosis, gynecologists need to be aware of the possibility of locally advanced cervical cancer, and perform relevant preoperative assessments and plan management.

Refractive index in the JUNO liquid scintillator

In the field of rare event physics, it is common to have huge masses of organic liquid scintillator as detection medium. In particular, they are widely used to study neutrino properties or astrophysical neutrinos. Thanks to its safety properties (such as low toxicity and high flash point) and easy scalability, linear alkyl benzene is the most common solvent used to produce liquid scintillators for large mass experiments. The knowledge of the refractive index is a pivotal point to understand the detector response, as this quantity (and its wavelength dependence) affects the Cherenkov radiation and photon propagation in the medium. In this paper, we report the measurement of the refractive index of the JUNO liquid scintillator between 260–1064 nm performed with two different methods to cover wide range of refractive index (an ellipsometer and a refractometer), with a sub percent level precision. In addition, we used an interferometer to measure the group velocity in the JUNO liquid scintillator and verify the expected value derived from the refractive index measurements.

(Invited) Doping Mechanisms and Defect Passivation of p-Type SnOx for Tfts and Bipolar Devices

Despite the outstanding achievements in multiple areas such as displays and energy, oxide electronics has been limited to single-polar (n-type) applications due to the facile generation of oxygen vacancies as native donors. On the contrary, the processing of p-type oxides is restrained due to the high formation energy of native acceptors. Furthermore, the oxygen 2p orbitals of the majority of oxide semiconductors are anisotropic and localized to the valence band maximum (VBM), resulting in a large effective mass of holes and hence low carrier mobility.Hybrid orbital electronic configurations with cation d10 (closed shell structure) and cation s2 (pseudo-closed structure) have been suggested initially in complex oxides (e.g., CuMO2 where M= Al, Ga, and In; and SrCu2O2) to delocalize the oxygen 2p orbitals from the VBM. However, these complex oxides require high temperatures to process and are difficult to engineer the electrical properties of carrier density and carrier mobility due to the correlated nature of multi-cation species. Several single-cation p-type oxides such as PbO, Bi2O3, and SnO have emerged as well, where the energy level of a unique s-orbital of cations is similar to oxygen 2p orbitals, forming strong hybrid structures. In addition, a simpler single-cation structure leads to easier control of electrical properties required in practical device applications such as thin film transistors (TFT) and complementary logic inverters.We previously reported scalable processing of p-type SnOx through thermodynamic-based interfacial reactions as well as reactive sputtering.1 More recently, we also suggested multi-modal encapsulation to enhance TFT on- and off-state behaviors and identified a defect complex as an effective p-type doping agent.2 However, challenges remain since the TFT off-state current is large, and the defect/trap state density is high.In this presentation, we share our approaches to engineer the off-state current and passivate the defect/trap states. In addition to channel thickness optimization, intrinsic (Sn vacancy or oxygen interstitial) and extrinsic (H-related species) doping strategies to adjust channel carrier density will be compared. The performance of several surface treatments (oxygen plasma and UV) and TFT back channel encapsulations (SiO2 and Al2O3) will be systematically compared. Then, the device performance of optimized p-type SnO TFTs and complementary inverters with n-type InZnO TFTs will be discussed.References Lee et al., ACS Applied Materials & Interfaces, 13 (46), 55676–55686 (2021)Lee et al., ACS Applied Materials & Interfaces, 14 (48), 53999–54011 (2022) AcknowledgmentsThis work was partially supported by National Science Foundation, Award number ECCS-1931088 and CBET-2207302.

Feasibility of keeping Mars warm with nanoparticles.

One-third of Mars' surface has shallow-buried H2O, but it is currently too cold for use by life. Proposals to warm Mars using greenhouse gases require a large mass of ingredients that are rare on Mars' surface. However, we show here that artificial aerosols made from materials that are readily available at Mars-for example, conductive nanorods that are ~9 micrometers long-could warm Mars >5 × 103 time smore effectively than the best gases. Such nanoparticles forward-scatter sunlight and efficiently block upwelling thermal infrared. Like the natural dust of Mars, they are swept high into Mars' atmosphere, allowing delivery from the near-surface. For a 10-year particle lifetime, two climate models indicate that sustained release at 30 liters per second would globally warm Mars by ≳30 kelvin and start to melt the ice. Therefore, if nanoparticles can be made at scale on (or delivered to) Mars, then the barrier to warming of Mars appears to be less high than previously thought.

Common issues and solutions in intraoperative frozen pathological diagnosis of small pulmonary nodules

With the development of chest CT screening, surgically resected lung tumors have shifted from predominantly large masses to predominantly small nodules. The intraoperative frozen diagnosis of pulmonary small nodules faces many challenges, such as the accurate understanding about the concepts of adenocarcinoma in situ, minimally invasive adenocarcinoma and lepidic adenocarcinoma, as well as their differential diagnosis with small size invasive adenocarcinoma, benign tumors (such as bronchiolar adenoma, sclerosing pneumocytoma, etc.), metastatic tumors and so on. This study summarizes some common problems encountered in the intraoperative frozen diagnosis of small pulmonary nodules in daily practice, focusing on the diagnosis and differential diagnosis of adenocarcinoma, in order to make the accurate intraoperative frozen diagnosis of small pulmonary nodules and diminish misdiagnosis.

An attractive model: simulating fuzzy dark matter with attractive self-interactions

Abstract Fuzzy Dark Matter (FDM) comprised of ultralight ($m \sim 10^{-22}~\rm {eV}$) boson particles has received significant attention as a viable alternative to Cold Dark Matter (CDM), as it approximates CDM on large scales (≳ 1 Mpc) while potentially resolving some of its small-scale problems via kiloparsec-scale quantum interference. However, the most basic FDM model, with one free parameter (the boson mass), is subject to a tension: small boson masses yield the desired cores of dwarf galaxies but underpredict structure in the Lyman-α forest, while large boson masses render FDM effectively identical to CDM. This Catch-22 problem may be alleviated by considering an axion-like particle with attractive particle self-interactions. We simulate an idealized FDM halo with self-interactions parameterized by an energy decay constant $f \sim 10^{15}~\rm {GeV}$ related to the axion symmetry-breaking conjectured to solve the strong-CP problem in particle physics. We observe solitons, a hallmark of FDM, condensing within a broader halo envelope, and find that the density profile and soliton mass depend on self-interaction strength. We propose generalized formulae to extend those from previous works to include self-interactions. We also investigate a critical mass threshold predicted for strong interactions at which the soliton collapses into a compact, unresolved state. We find that the collapse happens quickly and its effects are initially contained to the central region of the halo.

Atypical Presentation of a Cardiac Lipoma

Cardiac masses can have atypical presentations and diagnosis can be difficult because of limitations in imaging modalities. We report the case of a 69-year-old man with a history of hypertension and hyperlipidemia who presented with several months of dyspnea with exertion. There was a soft systolic murmur on exam. Transthoracic echocardiogram showed a large right atrial mass that appeared to be adherent to the interatrial septum. Considering the size and apparent attachment to the interatrial septum the suspicion was a myxoma. After further imaging however, including transesophageal echocardiogram, cardiac computed tomography (CT) and cardiac magnetic resonance imaging (MRI) the diagnosis changed to a lipoma. The patient had surgical resection of the mass which confirmed the diagnosis. A multi-imaging approach may be helpful and required to accurately diagnose cardiac masses.

Unusual “Mini-Rugby Ball” Pattern Solitary Lung Metastasis in Relapsed Ewing's Sarcoma

AbstractEwing's sarcoma (ES) is a mesenchymal origin malignant neoplasm that affects children and adolescents. It is the second most common type of bone sarcoma and accounts for approximately 1.5% of all childhood cancers with an annual incidence of 1 to 3 cases per million children under 16 years of age. In this article, we present the case of a 16-year-old adolescent girl. Lung metastasis at the initial diagnosis of ES is relatively uncommon but carries significant prognostic implications. Lung metastases in ES can vary significantly in size, ranging from small nodules (just a few millimeters in size) to the largest reported case being 15 cm. The size of the metastases impacts the choice of therapeutic strategies and the prognosis. Approximately 30% of patients with ES experience a relapse, with the lungs being a common site for metastatic disease. Relapsed lung metastasis on follow-up is a critical concern in the long-term management of ES. We describe a relapsed case of ES in a 16-year-old adolescent girl who presented with a solitary large metastatic right lung mass, with the longest dimension of 16 cm on craniocaudal measurement. The primary site of the tumor was the left distal femur, for which the patient received six cycles of neoadjuvant chemotherapy, followed by en bloc tumor excision and rotationplasty of the left distal femur, after which the patient received seven cycles of adjuvant chemotherapy. Subsequent 5 years of regular follow-up was asymptomatic. Later, the patient presented with back pain and cough, and was diagnosed with a solitary large right lung mass. Computed tomography (CT) guided biopsy of the right lung mass revealed a metastatic ES, for which she underwent chemoradiotherapy. This case highlights the large size of solitary lung metastases in relapsed ES.

Designing Dense, Robust, and Ion-Diffusion-Effective Electrodes from Natural Wood Material toward High-Volumetric-Performance Supercapacitors.

Assembling active materials into dense electrodes is a promising way to obtain high-volumetric-capacitance supercapacitors, but insufficient ion channels in the dense structure lead to a low rate capability. Herein, a dense and robust wood electrode with a large MXene volumetric mass loading (1.25 g cm-3) and abundant ion diffusion channels is designed via a facile capillary-force-driven self-densification strategy. Specifically, MXene is assembled onto a wood cell wall, endowing the wood electrode with good electrical conductivity (86 S cm-1) and high electrochemical activity (5.9 F cm-2 at 1 mA cm-2). Notably, the oriented channels along with spaces between adjacent microfibrils recast after densification ensure efficient ion transport for the wood electrode, achieving an excellent rate capability with a high capacitance retention of 77% from 1 to 20 mA cm-2. Meanwhile, the capillary force induces self-densification on the softened wood cell wall, resulting in a highly compact and robust structure for the wood electrode.

TFE Terpolymers: Once Promising - Are There Still Perspectives in the 21st Century: Synthesis, Characterization, and Properties-Part I.

Polytetrafluoroethylene (PTFE) exhibits outstanding properties such as high-temperature stability, low surface tension, and chemical resistance against most solvents, strong acids, and bases. However, these traits make it challenging to subject PTFE to standard polymer processing procedures, such as thermoforming and hot incremental forming. While polymer processing at temperatures above the melting point of PTFE is already demanding, the typically large molar mass of PTFE results in extremely high melt viscosities, complicating the processing of PTFE. Also, PTFE tends to decompose at temperatures close to its melting point. Therefore, fluoropolymers obtained by copolymerizing tetrafluoroethylene (TFE) with various co-monomers are studied as alternatives to PTFE (e.g., fluorinated ethylene-propylene (FEP)), combining its advantages with better processability. TFE terpolymers have emerged as desirable PTFE alternatives. This review provides an overview of the synthesis with various comonomers and microstructural analysis of PTFE terpolymers and the relationships between the microstructures of TFE terpolymers and their properties.

Dimensional reduction gauge and effective dimensional reduction in four-dimensional Yang-Mills theory

Motivated by one-dimensional color-electric flux-tube formation in four-dimensional (4D) QCD, we investigate a possibility of effective dimensional reduction in the 4D Yang-Mills (YM) theory. We propose a new gauge fixing of “dimensional reduction (DR) gauge” defined so as to minimize RDR≡∫d4sTr[Ax2(s)+Ay2(s)], which has a residual gauge symmetry for the gauge function Ω(t,z) like 2D QCD on the t−z plane. We investigate effective dimensional reduction in the DR gauge using SU(3) quenched lattice QCD at β=6.0. The amplitude of Ax(s) and Ay(s) are found to be strongly suppressed in the DR gauge. We consider “tz-projection” of Ax,y(s)→0 for the gauge configuration generated in the DR gauge, in a similar sense to Abelian projection in the maximally Abelian gauge. By the tz-projection in the DR gauge, the interquark potential is not changed, and At(s) and Az(s) play a dominant role in quark confinement. In the DR gauge, we calculate a spatial correlation ⟨TrA⊥(s)A⊥(s+ra⊥)⟩(⊥=x,y) and estimate the spatial mass of A⊥(s)(⊥=x,y) as M≃1.7 GeV. It is conjectured that this large mass makes A⊥(s) inactive and realizes the dominance of At(s) and Az(s) in infrared region in the DR gauge. We also calculate the spatial correlation of two temporal link-variables and find that the correlation decreases as exp(−mr) with m≃0.6 GeV. Using a crude approximation, the 4D YM theory is reduced into an ensemble of 2D YM systems with the coupling of g2D=gm. Published by the American Physical Society 2024

Urethral duplication with a large cystic dorsal penile mass in a newborn: a case report

BackgroundUrethral duplication is a rare urogenital anomaly with varying anatomical orientations leading to diverse clinical presentations. We present a case of urethral duplication in a neonate featuring a large dorsal cystic mass on the penis, an unusual presentation.Case presentationA term male neonate with a prenatally diagnosed 10 × 10 cm genitourinary cystic mass was delivered via caesarean section. Examination revealed a large cystic mass extending dorsally from the pubic symphysis over a flattened, elongated penile shaft with a single urethral opening in the glans and undescended testes. A size 6-French feeding tube inserted into the urethra drained the bladder.Urethral communication with the cystic mass was confirmed via voiding cystourethrogram and cyst enlargement noted during voiding. Cyst fluid analysis indicated a urinary origin. Computed tomography and ultrasound were not diagnostic. Initial imaging revealed a dorsal cystic mass projecting from the pubic symphysis without bladder connection.Surgical intervention at 3 weeks revealed a Type IIA-2 urethral duplication, with a dorsal hypoplastic urethra communicating with the posterior urethra. Correction included resection of the dorsal urethra, cyst excision, and reconstruction of the penis with the orthotopic ventral urethra and bilateral orchidopexies.Satisfactory functional and cosmetic outcomes were observed at 2 and 8 months after surgery.ConclusionThis case highlights the significance of identifying unique urethral duplication presentations. The novel occurrence of Type IIA-2 urethral duplication terminating in a dorsal cystic mass underscores diagnostic complexity, surgical intricacies, and aesthetic considerations associated with such cases.

Supermassive gauginos in supergravity inflation with high-scale SUSY breaking

A model of supergravity inflation we recently proposed can produce slow roll inflation and a realistic spectrum of particles even without F-term supersymmetry breaking. Supersymmetry is broken only by a D-term induced by a recently discovered new type of Fayet-Iliopoulos (FI) term. Almost all supersymmetric partners of the standard model fields can get masses as high as the inflationary Hubble scale. The exception is gauginos, for which the vanishing of F-terms implies an exact cancellation that keeps their masses exactly zero. To cure this problem without spoiling the simplicity of our model we introduce a new term that further enlarges the space of supergravity effective actions. It is an F-term that, similarly to the new FI term, becomes singular in the supersymmetric limit. We show that this term can produce large gaugino masses without altering the spectrum of other states and without lowering the cutoff of the effecive theory.

Ruptured giant splenic artery aneurysm with an exceptional concurrent gastric and transverse colonic fistula: A rare case report.

Splenic artery aneurysm (SAA) is a focal dilation of the splenic artery with varying etiologies including atherosclerosis, arteritis, or trauma. Giant SAAs with a diameter of 10 cm is rare and can lead to severe complications like rupture and fistulas. Therefore, an accurate and timely diagnosis and treatment are important. A 50-year-old male presented with acute epigastric pain and hemorrhagic shock. Considering his symptoms and examination, ultrasound, multi-slice computed tomography and digital subtraction angiography results, a ruptured giant splenic artery aneurysm complicated with an exceptional gastric and transverse colonic fistula was suspected. Ruptured giant splenic artery aneurysm. Left anterolateral thoracotomy to control the severe aortic bleeding just above the diaphragm, aneurysmectomy, splenectomy, and closing the gastric and transverse colon perforations. Multi-slice computed tomography demonstrated the presence of splenic artery aneurysm in the distal third measuring (10 × 12 cm) in diameter with a true lumen measuring (7 × 3.5 cm) and a large hematoma extending to the greater and lesser gastric curvature. Intraoperatively, a large pulsating mass was detected occupying the epigastrium and the left hypochondrium with severe adhesions with the stomach and transverse colon. Giant SAA with a diameter of 10 cm is rare and is associated with severe complications. Therefore, successful treatment of splenic artery aneurysms involves prompt diagnosis, immediate surgical intervention to control bleeding, and tailored approaches like thoracotomy to control the thoracic aorta for better hemodynamic stabilization, aiming to eliminate the aneurysm and reduce complications effectively.

Influence of the peel on online detecting soluble solids content of pomelo using Vis-NIR spectroscopy coupled with chemometric analysis

The application of Visible-near infrared spectroscopy (Vis-NIRs) to internal quality detection of pomelo with large sizes and thick peels is still challenging. Considering that the peel has a large mass ratio in pomelo and a great added value in industrial processing, a postharvest processing mode of grading after peeling without affecting consumption of pomelos may be an approach to avoid adverse influence of peel on soluble solids content (SSC) evaluation. In this study, we investigated the performance variation of Vis-NIRs for SSC online determination of pomelos with and without peel for the first time. An online detection system for pomelo spectra acquisition was developed, and the spectral characteristic difference of the intact and peeled pomelos was analyzed. Subsequently, the performance of calibration models was gradually improved and comparatively analyzed by various spectral processing and wavelength selection methods. Furthermore, convolutional neural network (CNN) was utilized to explore its ability for feature extraction. The results showed that combined with standard normal variate (SNV) and second order detrending and changeable-size moving window algorithms, the partial least squares regression (PLSR) model using spectra of peeled pomelos achieved the best prediction results. Specifically, the model attained a determination coefficient of prediction (Rp2) of 0.88, a root mean square error of prediction (RMSEP) of 0.294%, and a residual predictive deviation (RPD) value of 2.57. This study demonstrates that the peel has a significantly negative effect on the prediction performance and the CNN could be an alternative to conventional PLSR method. Our work may open new avenues for the internal quality assessment of agro-products with complex tissue structure.

AB064. Two case reports & review of literature: perioperative surgical management of symptomatic large non-functioning pituitary masses in early pregnancy.

Pituitary masses during pregnancy pose many challenges, requiring inputs from multidisciplinary teams. Where surgery is required, such as in cases of impending pituitary apoplexy, timing must be carefully selected. Several case reports have suggested good outcome with surgery in later trimesters or postpartum. However, insufficient data exists on surgical strategies for such patients with severe visual symptoms in early pregnancy. We report two patients with pituitary masses requiring surgical excision. Review of patients' notes and imaging, with literature review. A 35-year-old gravida 2 para 1 female at 9 weeks gestational age (GA) presented with chronic bitemporal hemianopia, with acute left eye blurring of vision, identified during a pre-employment screening test. Imaging revealed a 38 mm × 29 mm × 33 mm sellar mass with compression onto the optic chiasm. She had no significant hormonal imbalances other than hyperprolactinemia and newly diagnosed Hashimoto's thyroiditis. She underwent transsphenoidal resection, with histology showing pituitary adenoma with blood clots. Similarly, our second patient was a 37-year-old gravida 4 para 2 female at 12 weeks GA with worsening bitemporal hemianopia with a 25 mm × 21 mm × 18 mm sellar mass displacing and compressing the optic chiasm. After resection she had marked objective improvement in her vision, but developed diabetes insipidus, and final histology revealed pituicytoma. Preoperative considerations for timing of surgery include pituitary apoplexy or acutely worsening visual field deficit. The pituitary physiologically increases in size during pregnancy, which can compress the optic chiasm and worsen visual deficit. In the case of apoplexy, delayed identification can have devastating consequences. However, major surgery in the first trimester may increase spontaneous miscarriage. The effects of imaging investigations from radiation, or gadolinium contrast administration, are also uncertain. While surgical positioning remains unaffected, other intraoperative considerations include strictly avoiding hypotension and using pregnancy-safe agents. Postoperative considerations include correcting hormonal deficiencies of hypopituitarism, including acute central hypocortisolism, diabetes insipidus and interruption of gonadotrophin production which could negatively affect pregnancy. Fetal heart rate must also be assessed. Determining timing of surgery to ensure well-being of both mother and fetus involves a difficult balance of risks. In our two cases, a thorough discussion with multidisciplinary input was required to achieve good outcomes.

Layered oxyiodide CdBiO2I: An efficient visible light responsive and scalable photocatalyst

Developing high-performance visible-light driven photocatalyst (λ≥420 nm) makes significance for the efficient utilization of solar energy. Mass production and easy recycling are equally important for the practical application of powdery photocatalyst. However, it is challenging to meet the above requirements at the same time. In this work, we develop an efficient visible-light responsive layered oxyiodide CdBiO2I nanosheets prepared by a facile direct precipitation method at ambient atmosphere, and demonstrate its upgradable features well fitting potential application. CdBiO2I has a layered crystal structure consisting of [CdBiO2]+ layer and I– single layer, differing from that of BiOI composed of [BiO2]2+ layer and I- double layers. It displays an absorption edge of 520 nm in visible region, with a band gap of 2.52 eV. CdBiO2I has a large intrinsic effective mass difference of hole/electron, exceeding BiOI by 8-fold, which results in much higher charge separation efficiency and production of more reactive species (superoxide radicals and holes). The degradation efficiency of CdBiO2I nanosheets for tetracycline hydrochloride reaches 84% under the visible light irradiation within 1 h, in which the degradation rate is 10 times that of BiOI. In addition, mass production (12 g catalyst at one time) and immobilization onto porous polyurethane foam of CdBiO2I powder are also demonstrated, which indicates the scalable properties and easy recovery of the catalyst, highlighting the advantages of the current preparation method and prefiguring its potential in practical applications. This work may enlighten future research on the exploitation of solar-driven catalyst with high efficiency and strong practical applicability.

Preoperative risk factors for skeletal muscle mass loss in patients with biliary tract cancer.

Endoscopic retrograde cholangiography (ERC)-related procedures, usually performed before biliary tract cancer (BTC) surgery, are associated with increased risk for various complications, which can cause sarcopenia. No study has previously elucidated the relationship between preoperative ERC-related procedures and sarcopenia/skeletal muscle mass loss. Patients with BTC who underwent radical surgical resection following ERC-related procedures were included. Skeletal muscle mass was evaluated using the psoas muscle mass index (PMI), which was determined using computed tomography images, and the change in PMI before the initial pre-ERC and surgery (ΔPMI) was calculated. Risk factors for advanced skeletal muscle mass loss, defined as a large ΔPMI, were evaluated. The study cohort included 90 patients with a median age of 72 (interquartile range, 65-75) years. The median PMI pre-ERC and surgery was 4.40 and 4.15 cm2/m2, respectively (p < .01). The median ΔPMI was -6.2% (interquartile range, -10.9% to 0.5%). By multivariate analysis, post-ERC pancreatitis and cholangitis before surgery were independent predictive factors for large PMI loss (odds ratio, 4.57 and 3.18, respectively; p = .03 and p = .02, respectively). Skeletal muscle mass decreases preoperatively in most patients with BTC undergoing ERC. Post-ERC pancreatitis and cholangitis before surgery were independent risk factors for large skeletal muscle mass loss.