Identification of Lipomatous Metaplasia in a Cortisol-secreting Adrenocortical Adenoma Treated With Mifepristone.

Adrenal adenomas are benign tumors of the adrenal cortex that may secrete excess hormones, such as cortisol. They are most commonly discovered during imaging studies for unrelated problems. Lipomatous metaplasia is a rare degenerative change in adrenal adenomas, characterized by the presence of adipose tissue and hematopoietic elements within the tumor. In this report, we present a case of an adrenal adenoma with lipomatous metaplasia in a patient with hypertension, hyperlipidemia, and type II diabetes mellitus. The discovery of this adrenal mass was prompted by an evaluation of the patient's progressive hirsutism. The tumor was found to be secreting cortisol, leading to Cushing syndrome. The patient subsequently underwent surgical resection of the mass after being treated with mifepristone. The histopathological examination confirmed it to be an adrenal cortical neoplasm with lipomatous metaplasia, characterized by uncertain malignant potential. The patient did well postoperatively. Three months after left adrenalectomy, the patient's hirsutism, A1c, and hypertension improved, allowing a reduction in antihypertensives. Her body mass index stabilized, her triglyceride decreased, and her dehydroepiandrosterone sulfate level normalized. She continued to do well at follow-up visits. Overall, this was a rare case of a functioning adrenal adenoma with lipomatous metaplasia, presenting both diagnostic and therapeutic challenges.

CTLESS: A scatter-window projection and deep learning-based transmission-less attenuation compensation method for myocardial perfusion SPECT.

Attenuation compensation (AC), while being beneficial for visual-interpretation tasks in myocardial perfusion imaging (MPI) by SPECT, typically requires the availability of a separate X-ray CT component, leading to additional radiation dose, higher costs, and potentially inaccurate diagnosis due to SPECT/CT misalignment. To address these issues, we developed a method for cardiac SPECT AC using deep learning and emission scatter-window photons without a separate transmission scan (CTLESS). In this method, an estimated attenuation map reconstructed from scatter-energy window projections is segmented into different regions using a multi-channel input multi-decoder network trained on CT scans. Pre-defined attenuation coefficients are assigned to these regions, yielding the attenuation map used for AC. We objectively evaluated this method in a retrospective study with anonymized clinical SPECT/CT stress MPI images on the clinical task of detecting defects with an anthropomorphic model observer. CTLESS yielded statistically non-inferior performance compared to a CT-based AC (CTAC) method and significantly outperformed a non-AC (NAC) method on this clinical task. Similar results were observed in stratified analyses with different sexes, defect extents and severities. The method was observed to generalize across two SPECT scanners, each with a different camera. In addition, CTLESS yielded similar performance as CTAC and outperformed NAC method on the metrics of root mean squared error and structural similarity index measure. Moreover, as we reduced the training dataset size, CTLESS yielded relatively stable AUC values and generally outperformed another DL-based AC method that directly estimated the attenuation coefficient within each voxel. These results demonstrate the capability of the CTLESS method for transmission-less AC in SPECT and motivate further clinical evaluation.

Extensive Dural Venous Thrombosis With Associated Intracerebral Hemorrhage and Subarachnoid Hemorrhage Due to Protein S Deficiency: A Case Report.

Cerebral venous thrombosis (CVT) is an uncommon but potentially severe condition, typically affecting younger individuals, pregnant women, and those with underlying thrombophilia. We report a rare case of a 63-year-old female who presented with altered mental status, facial droop, and slurred speech and was found to have an extensive dural venous thrombosis complicated by intracerebral and subarachnoid hemorrhage due to protein S deficiency. Given her diagnosis of protein S deficiency and thrombosis, careful anticoagulation was initiated, resulting in both clinical and radiographic improvement.

BATF is a major driver of NK cell epigenetic reprogramming and dysfunction in AML.

Myelodysplastic syndrome and acute myeloid leukemia (AML) belong to a continuous disease spectrum of myeloid malignancies with poor prognosis in the relapsed/refractory setting necessitating novel therapies. Natural killer (NK) cells from patients with myeloid malignancies display global dysfunction with impaired killing capacity, altered metabolism, and an exhausted phenotype at the single-cell transcriptomic and proteomic levels. In this study, we identified that this dysfunction was mediated through a cross-talk between NK cells and myeloid blasts necessitating cell-cell contact. NK cell dysfunction could be prevented by targeting the αvß-integrin/TGF-ß/SMAD pathway but, once established, was persistent because of profound epigenetic reprogramming. We identified BATF as a core transcription factor and the main mediator of this NK cell dysfunction in AML. Mechanistically, we found that BATF was directly regulated and induced by SMAD2/3 and, in turn, bound to key genes related to NK cell exhaustion, such as HAVCR2, LAG3, TIGIT, and CTLA4. BATF deletion enhanced NK cell function against AML in vitro and in vivo. Collectively, our findings reveal a previously unidentified mechanism of NK immune evasion in AML manifested by epigenetic rewiring and inactivation of NK cells by myeloid blasts. This work highlights the importance of using healthy allogeneic NK cells as an adoptive cell therapy to treat patients with myeloid malignancies combined with strategies aimed at preventing the dysfunction by targeting the TGF-ß pathway or BATF.

Disseminated Varicella-Zoster Virus Presenting With Pneumonitis and Diffuse Alveolar Hemorrhage in an Immunocompetent Patient.

Varicella pneumonitis is typically seen in individuals with risk factors such as male gender, smoking history, and immunocompromised state and is often associated with disseminated infection, whereas primary varicella-zoster virus (VZV) infection usually involves a diffuse vesicular rash and rarely progresses to viral pneumonia. VZV pneumonitis accompanied by disseminated VZV infection is associated with a high mortality rate and may progress to diffuse alveolar hemorrhage in severe cases. In addition to cutaneous lesions, patients typically develop dyspnea, cough, tachypnea, chest pain, fever, and hemoptysis. Here, we present a rare case of disseminated VZV infection in an immunocompetent patient with pneumonitis and diffuse alveolar hemorrhage.

Theranostics in Neuroendocrine Tumors: Updates and Emerging Technologies.

Advancements in somatostatin receptor (SSTR) targeted imaging and treatment of well-differentiated neuroendocrine tumors (NETs) have revolutionized the management of these tumors. This comprehensive review delves into the current practice, discussing the use of the various FDA-approved SSTR-agonist PET tracers and the predictive imaging biomarkers, and elaborating on Lu177-DOTATATE peptide receptor radionuclide therapy (PRRT) including the evolving areas of post-therapy imaging practices, PRRT retreatment, and the potential role of dosimetry in optimizing patient treatments. The future directions sections highlight ongoing research on investigational PET imaging radiotracers, future prospects in alpha particle therapy, and combination therapy strategies.

Cryo-EM structure of the R388 plasmid conjugative pilus reveals a helical polymer characterized by an unusual pilin/phospholipid binary complex.

Bacterial conjugation is a process by which DNA is transferred unidirectionally from a donor cell to a recipient cell. It is the main means by which antibiotic resistance genes spread among bacterial populations. It is crucially dependent upon the elaboration of an extracellular appendage, termed "pilus," by a large double-membrane-spanning secretion system termed conjugative "type IV secretion system." Here we present the structure of the conjugative pilus encoded by the R388 plasmid. We demonstrate that, as opposed to all conjugative pili produced so far for cryoelectron microscopy (cryo-EM) structure determination, the conjugative pilus encoded by the R388 plasmid is greatly stimulated by the presence of recipient cells. Comparison of its cryo-EM structure with existing conjugative pilus structures highlights a number of important differences between the R388 pilus structure and that of its homologs, the most prominent being the highly distinctive conformation of its bound lipid.

Joint regional uptake quantification of thorium-227 and radium-223 using a multiple-energy-window projection-domain quantitative SPECT method.

Thorium-227 (227Th)-based α-particle radiopharmaceutical therapies (α-RPTs) are currently being investigated in several clinical and pre-clinical studies. After administration, 227Th decays to 223Ra, another α-particle-emitting isotope, which redistributes within the patient. Reliable dose quantification of both 227Th and 223Ra is clinically important, and SPECT may perform this quantification as these isotopes also emit X- and γ-ray photons. However, reliable quantification is challenging for several reasons: the orders-of-magnitude lower activity compared to conventional SPECT, resulting in a very low number of detected counts, the presence of multiple photopeaks, substantial overlap in the emission spectra of these isotopes, and the image-degrading effects in SPECT. To address these issues, we propose a multiple-energy-window projection-domain quantification (MEW-PDQ) method that jointly estimates the regional activity uptake of both 227Th and 223Ra directly using the SPECT projection data from multiple energy windows. We evaluated the method with realistic simulation studies conducted with anthropomorphic digital phantoms, including a virtual imaging trial, in the context of imaging patients with bone metastases of prostate cancer who were treated with 227Th-based α-RPTs. The proposed method yielded reliable (accurate and precise) regional uptake estimates of both isotopes and outperformed state-of-the-art methods across different lesion sizes and contrasts, as well as in the virtual imaging trial. This reliable performance was also observed with moderate levels of intra-regional heterogeneous uptake as well as when there were moderate inaccuracies in the definitions of the support of various regions. Additionally, we demonstrated the effectiveness of using multiple energy windows and the variance of the estimated uptake using the proposed method approached the Cramér-Rao-lower-bound-defined theoretical limit. These results provide strong evidence in support of this method for reliable uptake quantification in 227Th-based α-RPTs.

Unilateral C1-C2 Posterior Fusion in a Patient With Right Vertebral Artery Anomaly With Intracanal Trajectory: A Case Report.

CASE: A 59-year-old woman presented with progressively worsening neck pain and radicular symptoms. Cervical radiographs revealed C1-C2 dynamic instability. Magnetic resonance imaging and computed tomographic angiogram revealed an anomalous right vertebral artery with intracanal trajectory at C1. A unilateral left C1-C2 fusion with a C1 lateral mass screw and C2 transarticular screw placement was performed due to the anomalous artery. At 14-month follow-up, the patient's cervical symptoms had resolved. CONCLUSION: In this patient with an aberrant vertebral artery who was indicated for C1-C2 fusion, a unilateral contralateral fusion with a C1 lateral mass screw and C2 transarticular screw was a satisfactory treatment option.

The Multifaceted Impact of Gallstones: Understanding Complications and Management Strategies.

Gallstones, or cholelithiasis, represent a prevalent gastrointestinal disorder characterized by the formation of calculi within the gallbladder. This review aims to provide a comprehensive analysis of the complications associated with gallstones, with a focus on their pathophysiology, clinical manifestations, diagnostic methodologies, and management strategies. Gallstone-related complications encompass a broad spectrum, including biliary colic, acute cholecystitis, choledocholithiasis, acute pancreatitis, and cholangitis. The pathogenesis of these complications primarily involves biliary obstruction and subsequent infection, leading to significant morbidity and potential mortality. Diagnostic evaluation of gallstone complications employs various imaging techniques, such as ultrasonography, magnetic resonance cholangiopancreatography (MRCP), and endoscopic retrograde cholangiopancreatography (ERCP), each with distinct advantages and limitations. Therapeutic approaches are discussed, ranging from conservative management with pharmacotherapy and bile acid dissolution agents to interventional procedures like extracorporeal shock wave lithotripsy (ESWL) and percutaneous cholecystostomy. Surgical management, particularly laparoscopic cholecystectomy, remains the gold standard for definitive treatment. Additionally, advancements in endoscopic techniques, including endoscopic sphincterotomy (EST) and cholangioscopy, are highlighted. This review synthesizes current research findings and clinical guidelines, aiming to enhance the understanding and management of gallstone-related complications among healthcare professionals, thereby improving patient outcomes and reducing the burden of this common ailment.

Falling From Laughing: Laughing Gas-Induced Subacute Combined Degeneration From Nitrous Oxide.

Laughing gas is becoming increasingly popular as a recreational drug of choice, particularly among young adults. Nitrous oxide, the toxic component of laughing gas, can cause neuronal injury when used in high doses. Through multiple mechanisms, nitrous oxide leads to B12 depletion and subsequent demyelination, particularly in the spinal cord. Here, we present the case of a 27-year-old female who presented with ataxia and was found to have laughing gas-induced subacute combined degeneration from nitrous oxide. After aggressive vitamin B12 repletion and laughing gas cessation for three months, the patient improved.

Evaluating ChatGPT Responses on Atrial Fibrillation for Patient Education.

Background ChatGPT is a language model that has gained widespread popularity for its fine-tuned conversational abilities. However, a known drawback to the artificial intelligence (AI) chatbot is its tendency to confidently present users with inaccurate information. We evaluated the quality of ChatGPT responses to questions pertaining to atrial fibrillation for patient education. Our analysis included the accuracy and estimated grade level of answers and whether references were provided for the answers. Methodology ChatGPT was prompted four times and 16 frequently asked questions on atrial fibrillation from the American Heart Association were asked. Prompts included Form 1 (no prompt), Form 2 (patient-friendly prompt), Form 3 (physician-level prompt), and Form 4 (prompting for statistics/references). Responses were scored as incorrect, partially correct, or correct with references (perfect). Flesch-Kincaid grade-level unique words and response lengths were recorded for answers. Proportions of the responses at differing scores were compared using the chi-square analysis. The relationship between form and grade level was assessed using the analysis of variance. Results Across all forms, scoring frequencies were one (1.6%) incorrect, five (7.8%) partially correct, 55 (85.9%) correct, and three (4.7%) perfect. Proportions of responses that were at least correct did not differ by form (p = 0.350), but perfect responses did (p = 0.001). Form 2 answers had a lower mean grade level (12.80 ± 3.38) than Forms 1 (14.23 ± 2.34), 3 (16.73 ± 2.65), and 4 (14.85 ± 2.76) (p < 0.05). Across all forms, references were provided in only three (4.7%) answers. Notably, when additionally prompted for sources or references, ChatGPT still only provided sources on three responses out of 16 (18.8%). Conclusions ChatGPT holds significant potential for enhancing patient education through accurate, adaptive responses. Its ability to alter response complexity based on user input, combined with high accuracy rates, supports its use as an informational resource in healthcare settings. Future advancements and continuous monitoring of AI capabilities will be crucial in maximizing the benefits while mitigating the risks associated with AI-driven patient education.

Genetic and environmental effects on morphological traits of social phenotypes in wasps.

Many species exhibit distinct phenotypic classes, such as sexes in dioecious species or castes in social species. The evolution of these classes is affected by the genetic architecture governing traits shared between phenotypes. However, estimates of the genetic and environmental factors contributing to phenotypic variation in distinct classes have rarely been examined. We studied the genetic architecture underlying morphological traits in phenotypic classes in the social wasp Vespula maculifrons. Our data revealed patriline effects on a few traits, indicating weak genetic influences on caste phenotypic variation. Interestingly, traits exhibited higher heritability in queens than workers. This result suggests that genetic variation has a stronger influence on trait variation in the queen caste than the worker caste, which is unexpected because queens typically experience direct selection. Moreover, estimates of heritability for traits were correlated between the castes, indicating that variability in trait size was governed by similar genetic architecture in the two castes. However, we failed to find evidence for a significant relationship between caste dimorphism and caste correlation, as would be expected if trait evolution was constrained by intralocus genetic conflict. Our analyses also uncovered variation in the allometric relationships for traits. These analyses suggested that worker traits were proportionally smaller than queen traits for most traits examined. Overall, our data provide evidence for a strong environmental and moderate genetic basis of trait variation among castes. Moreover, our results suggest that selection previously operated on caste phenotype in this species, and phenotypic variation is now governed primarily by environmental differences.

DEMIST: A Deep-Learning-Based Detection-Task-Specific Denoising Approach for Myocardial Perfusion SPECT.

There is an important need for methods to process myocardial perfusion imaging (MPI) single-photon emission computed tomography (SPECT) images acquired at lower-radiation dose and/or acquisition time such that the processed images improve observer performance on the clinical task of detecting perfusion defects compared to low-dose images. To address this need, we build upon concepts from model-observer theory and our understanding of the human visual system to propose a detection task-specific deep-learning-based approach for denoising MPI SPECT images (DEMIST). The approach, while performing denoising, is designed to preserve features that influence observer performance on detection tasks. We objectively evaluated DEMIST on the task of detecting perfusion defects using a retrospective study with anonymized clinical data in patients who underwent MPI studies across two scanners (N = 338). The evaluation was performed at low-dose levels of 6.25%, 12.5%, and 25% and using an anthropomorphic channelized Hotelling observer. Performance was quantified using area under the receiver operating characteristics curve (AUC). Images denoised with DEMIST yielded significantly higher AUC compared to corresponding low-dose images and images denoised with a commonly used task-agnostic deep learning-based denoising method. Similar results were observed with stratified analysis based on patient sex and defect type. Additionally, DEMIST improved visual fidelity of the low-dose images as quantified using root mean squared error and structural similarity index metric. A mathematical analysis revealed that DEMIST preserved features that assist in detection tasks while improving the noise properties, resulting in improved observer performance. The results provide strong evidence for further clinical evaluation of DEMIST to denoise low-count images in MPI SPECT.

Evaluating ChatGPT-3.5 and ChatGPT-4.0 Responses on Hyperlipidemia for Patient Education.

Introduction Hyperlipidemia is prevalent worldwide and affects a significant number of US adults. It significantly contributes to ischemic heart disease and millions of deaths annually. With the increasing use of the internet for health information, tools like ChatGPT (OpenAI, San Francisco, CA, USA) have gained traction. ChatGPT version 4.0, launched in March 2023, offers enhanced features over its predecessor but requires a monthly fee. This study compares the accuracy, comprehensibility, and response length of the free and paid versions of ChatGPT for patient education on hyperlipidemia. Materials and methods ChatGPT versions 3.5 and 4.0 were prompted in three different ways and 25 questions from the Cleveland Clinic's frequently asked questions (FAQs) on hyperlipidemia. Prompts included no prompting (Form 1), patient-friendly prompting (Form 2), and physician-level prompting (Form 3). Responses were categorized as incorrect, partially correct, or correct. Additionally, the grade level and word count from each response were recorded for analysis. Results Overall, scoring frequencies for ChatGPT version 3.5 were: five (6.67%) incorrect, 18 partially correct (24%), and 52 (69.33%) correct. Scoring frequencies for ChatGPT version 4.0 were: one (1.33%) incorrect, 18 (24.00%) partially correct, and 56 (74.67%) correct. Correct answers did not significantly differ between ChatGPT version 3.5 and ChatGPT version 4.0 (p = 0.586). ChatGPT version 3.5 had a significantly higher grade reading level than version 4.0 (p = 0.0002). ChatGPT version 3.5 had a significantly higher word count than version 4.0 (p = 0.0073). Discussion There was no significant difference in accuracy between the free and paid versions of hyperlipidemia FAQs. Both versions provided accurate but sometimes partially complete responses. Version 4.0 offered more concise and readable information, aligning with the readability of most online medical resources despite exceeding the National Institutes of Health's (NIH's) recommended eighth-grade reading level. The paid version demonstrated superior adaptability in tailoring responses based on the input. Conclusion Both versions of ChatGPT provide reliable medical information, with the paid version offering more adaptable and readable responses. Healthcare providers can recommend ChatGPT as a source of patient education, regardless of the version used. Future research should explore diverse question formulations and ChatGPT's handling of incorrect information.

Deep learning generation of preclinical positron emission tomography (PET) images from low-count PET with task-based performance assessment.

BACKGROUND: Preclinical low-count positron emission tomography (LC-PET) imaging offers numerous advantages such as facilitating imaging logistics, enabling longitudinal studies of long- and short-lived isotopes as well as increasing scanner throughput. However, LC-PET is characterized by reduced photon-count levels resulting in low signal-to-noise ratio (SNR), segmentation difficulties, and quantification uncertainties. PURPOSE: We developed and evaluated a novel deep-learning (DL) architecture-Attention based Residual-Dilated Net (ARD-Net)-to generate standard-count PET (SC-PET) images from LC-PET images. The performance of the ARD-Net framework was evaluated for numerous low count realizations using fidelity-based qualitative metrics, task-based segmentation, and quantitative metrics. METHOD: Patient Derived tumor Xenograft (PDX) with tumors implanted in the mammary fat-pad were subjected to preclinical [18F]-Fluorodeoxyglucose (FDG)-PET/CT imaging. SC-PET images were derived from a 10 min static FDG-PET acquisition, 50 min post administration of FDG, and were resampled to generate four distinct LC-PET realizations corresponding to 10%, 5%, 1.6%, and 0.8% of SC-PET count-level. ARD-Net was trained and optimized using 48 preclinical FDG-PET datasets, while 16 datasets were utilized to assess performance. Further, the performance of ARD-Net was benchmarked against two leading DL-based methods (Residual UNet, RU-Net; and Dilated Network, D-Net) and non-DL methods (Non-Local Means, NLM; and Block Matching 3D Filtering, BM3D). The performance of the framework was evaluated using traditional fidelity-based image quality metrics such as Structural Similarity Index Metric (SSIM) and Normalized Root Mean Square Error (NRMSE), as well as human observer-based tumor segmentation performance (Dice Score and volume bias) and quantitative analysis of Standardized Uptake Value (SUV) measurements. Additionally, radiomics-derived features were utilized as a measure of quality assurance (QA) in comparison to true SC-PET. Finally, a performance ensemble score (EPS) was developed by integrating fidelity-based and task-based metrics. Concordance Correlation Coefficient (CCC) was utilized to determine concordance between measures. The non-parametric Friedman Test with Bonferroni correction was used to compare the performance of ARD-Net against benchmarked methods with significance at adjusted p-value ≤0.01. RESULTS: ARD-Net-generated SC-PET images exhibited significantly better (p ≤ 0.01 post Bonferroni correction) overall image fidelity scores in terms of SSIM and NRMSE at majority of photon-count levels compared to benchmarked DL and non-DL methods. In terms of task-based quantitative accuracy evaluated by SUVMean and SUVPeak, ARD-Net exhibited less than 5% median absolute bias for SUVMean compared to true SC-PET and lower degree of variability compared to benchmarked DL and non-DL based methods in generating SC-PET. Additionally, ARD-Net-generated SC-PET images displayed higher degree of concordance to SC-PET images in terms of radiomics features compared to non-DL and other DL approaches. Finally, the ensemble score suggested that ARD-Net exhibited significantly superior performance compared to benchmarked algorithms (p ≤ 0.01 post Bonferroni correction). CONCLUSION: ARD-Net provides a robust framework to generate SC-PET from LC-PET images. ARD-Net generated SC-PET images exhibited superior performance compared other DL and non-DL approaches in terms of image-fidelity based metrics, task-based segmentation metrics, and minimal bias in terms of task-based quantification performance for preclinical PET imaging.

ISIT-QA: In Silico Imaging Trial to Evaluate a Low-Count Quantitative SPECT Method Across Multiple Scanner-Collimator Configurations for 223Ra-Based Radiopharmaceutical Therapies.

Personalized dose-based treatment planning requires accurate and reproducible noninvasive measurements to ensure safety and effectiveness. Dose estimation using SPECT is possible but challenging for alpha (α)-particle-emitting radiopharmaceutical therapy (α-RPT) because of complex γ-emission spectra, extremely low counts, and various image-degrading artifacts across a plethora of scanner-collimator configurations. Through the incorporation of physics-based considerations and skipping of the potentially lossy voxel-based reconstruction step, a recently developed projection-domain low-count quantitative SPECT (LC-QSPECT) method has the potential to provide reproducible, accurate, and precise activity concentration and dose measures across multiple scanners, as is typically the case in multicenter settings. To assess this potential, we conducted an in silico imaging trial to evaluate the LC-QSPECT method for a 223Ra-based α-RPT, with the trial recapitulating patient and imaging system variabilities. Methods: A virtual imaging trial titled In Silico Imaging Trial for Quantitation Accuracy (ISIT-QA) was designed with the objectives of evaluating the performance of the LC-QSPECT method across multiple scanner-collimator configurations and comparing performance with a conventional reconstruction-based quantification method. In this trial, we simulated 280 realistic virtual patients with bone-metastatic castration-resistant prostate cancer treated with 223Ra-based α-RPT. The trial was conducted with 9 simulated SPECT scanner-collimator configurations. The primary objective of this trial was to evaluate the reproducibility of dose estimates across multiple scanner-collimator configurations using LC-QSPECT by calculating the intraclass correlation coefficient. Additionally, we compared the reproducibility and evaluated the accuracy of both considered quantification methods across multiple scanner-collimator configurations. Finally, the repeatability of the methods was evaluated in a test-retest study. Results: In this trial, data from 268 223RaCl2 treated virtual prostate cancer patients, with a total of 2,903 lesions, were used to evaluate LC-QSPECT. LC-QSPECT provided dose estimates with good reproducibility across the 9 scanner-collimator configurations (intraclass correlation coefficient > 0.75) and high accuracy (ensemble average values of recovery coefficients ranged from 1.00 to 1.02). Compared with conventional reconstruction-based quantification, LC-QSPECT yielded significantly improved reproducibility across scanner-collimator configurations, accuracy, and test-retest repeatability ([Formula: see text] Conclusion: LC-QSPECT provides reproducible, accurate, and repeatable dose estimations in 223Ra-based α-RPT as evaluated in ISIT-QA. These findings provide a strong impetus for multicenter clinical evaluations of LC-QSPECT in dose quantification for α-RPTs.

The Role of Perioperative Nutritional Status and Supplementation in Orthopaedic Surgery: A Review of Postoperative Outcomes.

¼ Identification of malnourished and at-risk patients should be a standardized part of the preoperative evaluation process for every patient.¼ Malnourishment is defined as a disorder of energy, protein, and nutrients based on the presence of insufficient energy intake, weight loss, muscle atrophy, loss of subcutaneous fat, localized or generalized fluid accumulation, or diminished functional status.¼ Malnutrition has been associated with worse outcomes postoperatively across a variety of orthopaedic procedures because malnourished patients do not have a robust metabolic reserve available for recovery after surgery.¼ Screening assessment and basic laboratory studies may indicate patients' nutritional risk; however, laboratory values are often not specific for malnutrition, necessitating the use of prognostic screening tools.¼ Nutrition consultation and perioperative supplementation with amino acids and micronutrients are 2 readily available interventions that orthopaedic surgeons can select for malnourished patients.

How accurately can quantitative imaging methods be ranked without ground truth: An upper bound on no-gold-standard evaluation.

Objective evaluation of quantitative imaging (QI) methods with patient data, while important, is typically hindered by the lack of gold standards. To address this challenge, no-gold-standard evaluation (NGSE) techniques have been proposed. These techniques have demonstrated efficacy in accurately ranking QI methods without access to gold standards. The development of NGSE methods has raised an important question: how accurately can QI methods be ranked without ground truth. To answer this question, we propose a Cramer-Rao bound (CRB)-based framework that quantifies the upper bound in ranking QI methods without any ground truth. We present the application of this framework in guiding the use of a well-known NGSE technique, namely the regression-without-truth (RWT) technique. Our results show the utility of this framework in quantifying the performance of this NGSE technique for different patient numbers. These results provide motivation towards studying other applications of this upper bound.