Hyperpolarized 13 C metabolic imaging of the human abdomen with spatiotemporal denoising.

PURPOSE: Improving the quality and maintaining the fidelity of large coverage abdominal hyperpolarized (HP) 13 C MRI studies with a patch based global-local higher-order singular value decomposition (GL-HOVSD) spatiotemporal denoising approach. METHODS: Denoising performance was first evaluated using the simulated [1-13 C]pyruvate dynamics at different noise levels to determine optimal kglobal and klocal parameters. The GL-HOSVD spatiotemporal denoising method with the optimized parameters was then applied to two HP [1-13 C]pyruvate EPI abdominal human cohorts (n = 7 healthy volunteers and n = 8 pancreatic cancer patients). RESULTS: The parameterization of kglobal = 0.2 and klocal = 0.9 denoises abdominal HP data while retaining image fidelity when evaluated by RMSE. The kPX (conversion rate of pyruvate-to-metabolite, X = lactate or alanine) difference was shown to be <20% with respect to ground-truth metabolic conversion rates when there is adequate SNR (SNRAUC > 5) for downstream metabolites. In both human cohorts, there was a greater than nine-fold gain in peak [1-13 C]pyruvate, [1-13 C]lactate, and [1-13 C]alanine apparent SNRAUC . The improvement in metabolite SNR enabled a more robust quantification of kPL and kPA . After denoising, we observed a 2.1 ± 0.4 and 4.8 ± 2.5-fold increase in the number of voxels reliably fit across abdominal FOVs for kPL and kPA quantification maps. CONCLUSION: Spatiotemporal denoising greatly improves visualization of low SNR metabolites particularly [1-13 C]alanine and quantification of [1-13 C]pyruvate metabolism in large FOV HP 13 C MRI studies of the human abdomen.

Probing human heart TCA cycle metabolism and response to glucose load using hyperpolarized [2-13 C]pyruvate MRS.

INTRODUCTION: The healthy heart has remarkable metabolic flexibility that permits rapid switching between mitochondrial glucose oxidation and fatty acid oxidation to generate ATP. Loss of metabolic flexibility has been implicated in the genesis of contractile dysfunction seen in cardiomyopathy. Metabolic flexibility has been imaged in experimental models, using hyperpolarized (HP) [2-13 C]pyruvate MRI, which enables interrogation of metabolites that reflect tricarboxylic acid (TCA) cycle flux in cardiac myocytes. This study aimed to develop methods, demonstrate feasibility for [2-13 C]pyruvate MRI in the human heart for the first time, and assess cardiac metabolic flexibility. METHODS: Good manufacturing practice [2-13 C]pyruvic acid was polarized in a 5 T polarizer for 2.5-3 h. Following dissolution, quality control parameters of HP pyruvate met all safety and sterility criteria for pharmacy release, prior to administration to study subjects. Three healthy subjects each received two HP injections and MR scans, first under fasting conditions, followed by oral glucose load. A 5 cm axial slab-selective spectroscopy approach was prescribed over the left ventricle and acquired at 3 s intervals on a 3 T clinical MRI scanner. RESULTS: The study protocol, which included HP substrate injection, MR scanning, and oral glucose load, was performed safely without adverse events. Key downstream metabolites of [2-13 C]pyruvate metabolism in cardiac myocytes include the glycolytic derivative [2-13 C]lactate, TCA-associated metabolite [5-13 C]glutamate, and [1-13 C]acetylcarnitine, catalyzed by carnitine acetyltransferase (CAT). After glucose load, 13 C-labeling of lactate, glutamate, and acetylcarnitine from 13 C-pyruvate increased by an average of 39.3%, 29.5%, and 114% respectively in the three subjects, which could result from increases in lactate dehydrogenase, pyruvate dehydrogenase, and CAT enzyme activity as well as TCA cycle flux (glucose oxidation). CONCLUSIONS: HP [2-13 C]pyruvate imaging is safe and permits noninvasive assessment of TCA cycle intermediates and the acetyl buffer, acetylcarnitine, which is not possible using HP [1-13 C]pyruvate. Cardiac metabolite measurement in the fasting/fed states provides information on cardiac metabolic flexibility and the acetylcarnitine pool.

Mitigating the Counterpart Selection Effect for Standard Sirens.

The disagreement in the Hubble constant measured by different cosmological probes highlights the need for a better understanding of the observations or new physics. The standard siren method, a novel approach using gravitational-wave observations to determine the distance to binary mergers, has great potential to provide an independent measurement of the Hubble constant and shed light on the tension in the next few years. To realize this goal, we must thoroughly understand the sources of potential systematic bias of standard sirens. Among the known sources of systematic uncertainties, selection effects originating from electromagnetic counterpart observations of gravitational-wave sources may dominate the measurements with percent-level bias and no method to mitigate this effect is currently established. In this Letter, we develop a new formalism to mitigate the counterpart selection effect. We show that our formalism can reduce the systematic uncertainty of standard siren Hubble constant measurement to less than the statistical uncertainty with a simulated population of 200 observations (≲1%) for a realistic electromagnetic emission model. We conclude with how to apply our formalism to different electromagnetic emissions and observing scenarios.

Associations between transfusion reactions and thromboembolism development in blood-transfused patients: A retrospective cohort study.

BACKGROUND: Blood transfusion (BT) may be associated with an increased risk of thromboembolism. The associations between transfusion reactions (TRs) during BTs and potential risk factors for the development of thromboembolism in patients underwent blood transfusion have not been analyzed. Therefore, this study aimed to compare risk factors associated with the development of venous thromboembolism (VTE) or pulmonary embolism (PE) between patients underwent blood transfusion with and without TRs. STUDY DESIGNS AND METHODS: The retrospective study was conducted between April 1, 2017, and March 31, 2020, at a medical center in Taiwan. Blood-transfused patients were grouped into two cohorts as follows: those who experienced TRs and those who did not experience TRs. Both cohorts were subjected to follow-up until March 31, 2021. The endpoints for both groups were the occurrence of VTE or PE or the date of March 31, 2021. To investigate between-cohort risk differences, a Kaplan-Meier survival analysis and multiple Cox proportional hazard model was used. RESULTS: A total of 10,759 patients underwent 59,385 transfusion procedures, with 703 patients in the TR group, and 10,056 patients in the non-TR group. The risk of VTE or PE was twice as high in the TR group than in the non-TR group (adjusted hazard ratio 2.53, 95% confidence interval 1.49-4.29, p = .001). Meanwhile, age, female sex, transfusion frequency increment, and being nondiabetic was associated with an increased risk of developing thromboembolism. CONCLUSION: TRs are associated with increased long-term thromboembolism risk in patients underwent blood transfusion. It is imperative for clinicians to acknowledge this and maintain rigorous follow-up.

Unveiling the Incidence and Graft Survival Rate in Kidney Transplant Recipients With De Novo Thrombotic Microangiopathy: A Systematic Review and Meta-Analysis.

De novo thrombotic microangiopathy (TMA) is a rare and challenging condition in kidney transplant recipients, with limited research on its incidence and impact on graft survival. This study conducted a systematic review and meta-analysis of 28 cohorts/single-arm studies and 46 case series/reports from database inception to June 2022. In meta-analysis, among 14,410 kidney allograft recipients, de novo TMA occurred in 3.20% [95% confidence interval (CI): 1.93-4.77], with systemic and renal-limited TMA rates of 1.38% (95% CI: 06.5-2.39) and 2.80% (95% CI: 1.27-4.91), respectively. The overall graft loss rate of de novo TMA was 33.79% (95% CI: 26.14-41.88) in meta-analysis. This study provides valuable insights into the incidence and graft outcomes of de novo TMA in kidney transplant recipients.

A two per cent Hubble constant measurement from standard sirens within five years.

Gravitational-wave detections provide a novel way to determine the Hubble constant1-3, which is the current rate of expansion of the Universe. This 'standard siren' method, with the absolute distance calibration provided by the general theory of relativity, was used to measure the Hubble constant using the gravitational-wave detection of the binary neutron-star merger, GW170817, by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo4, combined with optical identification of the host galaxy5,6 NGC 4993. This independent measurement is of particular interest given the discrepancy between the value of the Hubble constant determined using type Ia supernovae via the local distance ladder (73.24 ± 1.74 kilometres per second per megaparsec) and the value determined from cosmic microwave background observations (67.4 ± 0.5 kilometres per second per megaparsec): these values differ7,8 by about 3σ. Local distance ladder observations may achieve a precision of one per cent within five years, but at present there are no indications that further observations will substantially reduce the existing discrepancies9. Here we show that additional gravitational-wave detections by LIGO and Virgo can be expected to constrain the Hubble constant to a precision of approximately two per cent within five years and approximately one per cent within a decade. This is because observing gravitational waves from the merger of two neutron stars, together with the identification of a host galaxy, enables a direct measurement of the Hubble constant independent of the systematics associated with other available methods. In addition to clarifying the discrepancy between existing low-redshift (local ladder) and high-redshift (cosmic microwave background) measurements, a precision measurement of the Hubble constant is of crucial value in elucidating the nature of dark energy10,11.

Identifying factors associated with substantially reduced adult height in patients with juvenile idiopathic arthritis: a retrospective cohort study.

BACKGROUND: Juvenile idiopathic arthritis (JIA), an autoimmune disease affecting children or adolescents and causing joint or systemic symptoms, reportedly has a negative effect on the patients' body height. This study aimed to identify factors attributable to substantially reduced adult height (SRAH) in JIA patients. METHODS: This single-center retrospective cohort study included patients from 2009 to 2019 in Taiwan. We collected JIA patients aged > 18 years at enrollment with a definite diagnosis and undergoing regular outpatient clinic follow-up or disease remission. Target height difference (THD), defined by adult height minus mid-parental height, was calculated for each patient. The calculation results yielded two groups, of which positive THD was defined as the optimal height (OH group) and those with THD below two standardized deviations as the SRAH group. Descriptive statistics and logistic regression analysis were used to analyze the data. RESULTS: Of 92 JIA patients, 57 and 12 were in the OH and the SRAH groups. Earlier disease onset, especially before the six-year-old, was noted in the SRAH group (p = 0.026). The distribution of JIA subtypes differed significantly between the two groups (p < 0.001); enthesis-related arthritis was the commonest subtype in the OH group, and systemic JIA was the commonest in the SRAH group. Half of the patients in the SRAH group had an active disease status at enrollment, which was higher than the OH group (50.0% vs. 21.1%, p = 0.066). More patients in the SRAH group had received orthopedic surgery due to JIA (25% vs. 3.5%, p = 0.034). Multiple logistic regression analysis showed that SRAH was independently related to systemic JIA (OR = 37.6, 95%CI 1.2-1210.5; p = 0.041). CONCLUSION: The subtype of systemic JIA, with its characteristics of early disease onset and active disease status, was the essential factor that significantly impacted adult height.

Computed tomography-based gastric volumetry for morbid obesity to assess weight loss and fatty liver change.

BACKGROUND/PURPOSE: Laparoscopic sleeve gastrectomy (LSG) is an effective treatment for patients with morbid obesity, but the optimal gastric volume (GV) for resection remains unclear. Accordingly, we aimed to determine the optimal percentage of excised stomach that could engender significant weight loss and improve fatty liver. METHODS: This prospective study included 63 patients. Computed tomography (CT) scans were performed before and 1 year after LSG to evaluate the gastric lumen (GL) and GV. Specifically, the stomach was distended with effervescent powder, following water-contrast mixture (20:1) and assessed by three-dimensional reconstruction. The correlations of reduced gastric lumen/volume (RGL/RGV) with total body weight (BW) loss and liver-spleen density ratio (LSDR) changes were analyzed, and optimal RGL/RGV associated with significant BW and fatty liver changes were determined. RESULTS: We noted a positive correlation between the percentage of RGV/RGL (%RGV/%RGL) and percentage of total weight loss (%TWL; r = 0.359, p = 0.004 and r = 0.271, p = 0.032). Furthermore, a %RGL value of >78.2% and %RGV value of >75.3% were associated with more significant BW loss than did limited excision (both p < 0.01). On the other hand, LSDR values increased significantly after LSG, corresponding to the improvement of fatty liver disease at %RGL and %RGV values of >59.1% and >56.4% (both p < 0.01), respectively. CONCLUSION: %RGV and %RGL were determined to be factors affecting LSG outcomes. LSG engendered significantly more BW loss when %RGV was >75.3% and resulted in fatty liver disease improvement when %RGV was >56.4%.

Oral mucosal lesions triage via YOLOv7 models.

BACKGROUND/PURPOSE: The global incidence of lip and oral cavity cancer continues to rise, necessitating improved early detection methods. This study leverages the capabilities of computer vision and deep learning to enhance the early detection and classification of oral mucosal lesions. METHODS: A dataset initially consisting of 6903 white-light macroscopic images collected from 2006 to 2013 was expanded to over 50,000 images to train the YOLOv7 deep learning model. Lesions were categorized into three referral grades: benign (green), potentially malignant (yellow), and malignant (red), facilitating efficient triage. RESULTS: The YOLOv7 models, particularly the YOLOv7-E6, demonstrated high precision and recall across all lesion categories. The YOLOv7-D6 model excelled at identifying malignant lesions with notable precision, recall, and F1 scores. Enhancements, including the integration of coordinate attention in the YOLOv7-D6-CA model, significantly improved the accuracy of lesion classification. CONCLUSION: The study underscores the robust comparison of various YOLOv7 model configurations in the classification to triage oral lesions. The overall results highlight the potential of deep learning models to contribute to the early detection of oral cancers, offering valuable tools for both clinical settings and remote screening applications.

Suppressing Anaphase-Promoting Complex/Cyclosome-Cell Division Cycle 20 Activity to Enhance the Effectiveness of Anti-Cancer Drugs That Induce Multipolar Mitotic Spindles.

Paclitaxel induces multipolar spindles at clinically relevant doses but does not substantially increase mitotic indices. Paclitaxel's anti-cancer effects are hypothesized to occur by promoting chromosome mis-segregation on multipolar spindles leading to apoptosis, necrosis and cyclic-GMP-AMP Synthase-Stimulator of Interferon Genes (cGAS-STING) pathway activation in daughter cells, leading to secretion of type I interferon (IFN) and immunogenic cell death. Eribulin and vinorelbine have also been reported to cause increases in multipolar spindles in cancer cells. Recently, suppression of Anaphase-Promoting Complex/Cyclosome-Cell Division Cycle 20 (APC/C-CDC20) activity using CRISPR/Cas9 mutagenesis has been reported to increase sensitivity to Kinesin Family 18a (KIF18a) inhibition, which functions to suppress multipolar mitotic spindles in cancer cells. We propose that a way to enhance the effectiveness of anti-cancer agents that increase multipolar spindles is by suppressing the APC/C-CDC20 to delay, but not block, anaphase entry. Delaying anaphase entry in genomically unstable cells may enhance multipolar spindle-induced cell death. In genomically stable healthy human cells, delayed anaphase entry may suppress the level of multipolar spindles induced by anti-cancer drugs and lower mitotic cytotoxicity. We outline specific combinations of molecules to investigate that may achieve the goal of enhancing the effectiveness of anti-cancer agents.

Hyperpolarized [2-13C]pyruvate MR molecular imaging with whole brain coverage.

Hyperpolarized (HP) 13C Magnetic Resonance Imaging (MRI) was applied for the first time to image and quantify the uptake and metabolism of [2-13C]pyruvate in the human brain to provide new metabolic information on cerebral energy metabolism. HP [2-13C]pyruvate was injected intravenously and imaged in 5 healthy human volunteer exams with whole brain coverage in a 1-minute acquisition using a specialized spectral-spatial multi-slice echoplanar imaging (EPI) pulse sequence to acquire 13C-labeled volumetric and dynamic images of [2-13C]pyruvate and downstream metabolites [5-13C]glutamate and [2-13C]lactate. Metabolic ratios and apparent conversion rates of pyruvate-to-lactate (kPL) and pyruvate-to-glutamate (kPG) were quantified to investigate simultaneously glycolytic and oxidative metabolism in a single injection.

Model-constrained reconstruction accelerated with Fourier-based undersampling for hyperpolarized [1-13 C] pyruvate imaging.

PURPOSE: Model-constrained reconstruction with Fourier-based undersampling (MoReFUn) is introduced to accelerate the acquisition of dynamic MRI using hyperpolarized [1-13 C]-pyruvate. METHODS: The MoReFUn method resolves spatial aliasing using constraints introduced by a pharmacokinetic model that describes the signal evolution of both pyruvate and lactate. Acceleration was evaluated on three single-channel data sets: a numerical digital phantom that is used to validate the accuracy of reconstruction and model parameter restoration under various SNR and undersampling ratios, prospectively and retrospectively sampled data of an in vitro dynamic multispectral phantom, and retrospectively undersampled imaging data from a prostate cancer patient to test the fidelity of reconstructed metabolite time series. RESULTS: All three data sets showed successful reconstruction using MoReFUn. In simulation and retrospective phantom data, the restored time series of pyruvate and lactate maintained the image details, and the mean square residual error of the accelerated reconstruction increased only slightly (< 10%) at a reduction factor up to 8. In prostate data, the quantitative estimation of the conversion-rate constant of pyruvate to lactate was achieved with high accuracy of less than 10% error at a reduction factor of 2 compared with the conversion rate derived from unaccelerated data. CONCLUSION: The MoReFUn technique can be used as an effective and reliable imaging acceleration method for metabolic imaging using hyperpolarized [1-13 C]-pyruvate.

Hyperpolarized 13 C Metabolic MRI of Patients with Pancreatic Ductal Adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDA) is the third leading cause of cancer-related death in the United States. However, early response assessment using the current approach of measuring changes in tumor size on computed tomography (CT) or MRI is challenging. PURPOSE: To investigate the feasibility of hyperpolarized (HP) [1-13 C]pyruvate MRI to quantify metabolism in the normal appearing pancreas and PDA, and to assess changes in PDA metabolism following systemic chemotherapy. STUDY TYPE: Prospective. SUBJECTS: Six patients (65.0 ± 7.6 years, 2 females) with locally advanced or metastatic PDA enrolled prior to starting a new line of systemic chemotherapy. FIELD STRENGTH/SEQUENCE: 3-T, T1-weighted gradient echo, metabolite-selective 13 C echoplanar imaging. ASSESSMENT: Time-resolved HP [1-13 C]pyruvate data were acquired before (N = 6) and 4-weeks after (N = 3) treatment initiation. Pyruvate metabolism, as quantified by pharmacokinetic modeling and metabolite area-under-the-curve ratios, was assessed in manually segmented PDA and normal appearing pancreas ROIs (N = 5). The change in tumor metabolism before and 4-weeks after treatment initiation was assessed in primary PDA (N = 2) and liver metastases (N = 1), and was compared to objective tumor response defined by response evaluation criteria in solid tumors (RECIST) on subsequent CTs. STATISTICAL TESTS: Descriptive tests (mean ± standard deviation), model fit error for pharmacokinetic rate constants. RESULTS: Primary PDA showed reduced alanine-to-lactate ratios when compared to normal pancreas, due to increased lactate-to-pyruvate or reduced alanine-to-pyruvate ratios. Of the three patients who received HP [1-13 C]pyruvate MRI before and 4-weeks after treatment initiation, one patient had a primary tumor with early metabolic response (increase in alanine-to-lactate) and subsequent partial response according to RECIST, one patient had a primary tumor with relatively stable metabolism and subsequent stable disease by RECIST, and one patient had metastatic PDA with increase in lactate-to-pyruvate of the liver metastases and corresponding progressive disease according to RECIST. DATA CONCLUSION: Altered pyruvate metabolism with increased lactate or reduced alanine was observed in the primary tumor. Early metabolic response assessed at 4-weeks after treatment initiation correlated with subsequent objective tumor response assessed using RECIST. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.

Twin-Boundary Reduced Surface Diffusion on Electrically Stressed Copper Nanowires.

Surface diffusion is intimately correlated with crystal orientation and surface structure. Fast surface diffusion accelerates phase transformation and structural evolution of materials. Here, through in situ transmission electron microscopy observation, we show that a copper nanowire with dense nanoscale coherent twin-boundary (CTB) defects evolves into a zigzag configuration under electric-current driven surface diffusion. The hindrance at the CTB-intercepted concave triple junctions decreases the effective surface diffusivity by almost 1 order of magnitude. The energy barriers for atomic migration at the concave junctions and different faceted surfaces are computed using density functional theory. We proposed that such a stable zigzag surface is shaped not only by the high-diffusivity facets but also by the stalled atomic diffusion at the concave junctions. This finding provides a defect-engineering route to develop robust interconnect materials against electromigration-induced failures for nanoelectronic devices.

Antineutrophil Cytoplasmic Antibody-Associated Vasculitis and the Risk of Developing Incidental Tuberculosis: A Population-Based Cohort Study.

Background and Objectives: Treatment for antineutrophil cytoplasmic antibody-associated vasculitis (AAV) must deal with immunosuppression, as well as infections associated with a compromised immune system, such as tuberculosis (TB). Our aim was to examine the risk of incidental TB after diagnosis of AAV. Materials and Methods: This retrospective population-based cohort study was based on the data from the National Health Insurance Research Database in Taiwan. Patients with newly diagnosed granulomatous polyangiitis or microscopic polyangiitis were identified between 1 January 2000 and 31 December 2012. The primary outcome was risk of incidental TB. Cox proportional hazard models were used to evaluate the association between AAV and incidental TB. Results: A total of 2257 patients with AAV and a propensity-score matched cohort of 9028 patients were studied. Overall, patients with AAV were at a 1.48× higher risk of contracting incidental TB than the patients in the matched cohort (adjusted HR 1.48; 95% confidence interval [CI], 1.02-2.15). Note that the highest risk of contracting incidental TB was in the first two years following a diagnosis of AAV, with a nearly 1-fold increase in risk (adjusted HR, 1.91; 95% CI, 1.01-3.60). Female AAV patients were 3.24× more likely than females without AAV to develop TB (adjusted HR 3.24; 95% CI, 1.85-5.67). Conclusions: Patients with AAV exhibit a 48% elevated TB risk, notably, a 91% increase within the first two years postdiagnosis. Female AAV patients face a 3.24 times higher TB risk compared to females without AAV. This study is limited by potential misclassification and overestimation of AAV cases. Clinicians should closely monitor TB risk in AAV patients, especially in females and the initial two years following diagnosis.

Improving multiparametric MR-transrectal ultrasound guided fusion prostate biopsies with hyperpolarized 13 C pyruvate metabolic imaging: A technical development study.

PURPOSE: To develop techniques and establish a workflow using hyperpolarized carbon-13 (13 C) MRI and the pyruvate-to-lactate conversion rate (kPL ) biomarker to guide MR-transrectal ultrasound fusion prostate biopsies. METHODS: The integrated multiparametric MRI (mpMRI) exam consisted of a 1-min hyperpolarized 13 C-pyruvate EPI acquisition added to a conventional prostate mpMRI exam. Maps of kPL values were calculated, uploaded to a picture archiving and communication system and targeting platform, and displayed as color overlays on T2 -weighted anatomic images. Abdominal radiologists identified 13 C research biopsy targets based on the general recommendation of focal lesions with kPL >0.02(s-1 ), and created a targeting report for each study. Urologists conducted transrectal ultrasound-guided MR fusion biopsies, including the standard 1 H-mpMRI targets as well as 12-14 core systematic biopsies informed by the research 13 C-kPL targets. All biopsy results were included in the final pathology report and calculated toward clinical risk. RESULTS: This study demonstrated the safety and technical feasibility of integrating hyperpolarized 13 C metabolic targeting into routine 1 H-mpMRI and transrectal ultrasound fusion biopsy workflows, evaluated via 5 men (median age 71 years, prostate-specific antigen 8.4 ng/mL, Cancer of the Prostate Risk Assessment score 2) on active surveillance undergoing integrated scan and subsequent biopsies. No adverse event was reported. Median turnaround time was less than 3 days from scan to 13 C-kPL targeting, and scan-to-biopsy time was 2 weeks. Median number of 13 C targets was 1 (range: 1-2) per patient, measuring 1.0 cm (range: 0.6-1.9) in diameter, with a median kPL of 0.0319 s-1 (range: 0.0198-0.0410). CONCLUSIONS: This proof-of-concept work demonstrated the safety and feasibility of integrating hyperpolarized 13 C MR biomarkers to the standard mpMRI workflow to guide MR-transrectal ultrasound fusion biopsies.

Development of specialized magnetic resonance acquisition techniques for human hyperpolarized [13 C,15 N2 ]urea + [1-13 C]pyruvate simultaneous perfusion and metabolic imaging.

PURPOSE: This study aimed to develop and demonstrate the in vivo feasibility of a 3D stack-of-spiral balanced steady-state free precession(3D-bSSFP) urea sequence, interleaved with a metabolite-specific gradient echo (GRE) sequence for pyruvate and metabolic products, for improving the SNR and spatial resolution of the first hyperpolarized 13 C-MRI human study with injection of co-hyperpolarized [1-13 C]pyruvate and [13 C,15 N2 ]urea. METHODS: A metabolite-specific bSSFP urea imaging sequence was designed using a urea-specific excitation pulse, optimized TR, and 3D stack-of-spiral readouts. Simulations and phantom studies were performed to validate the spectral response of the sequence. The image quality of urea data acquired by the 3D-bSSFP sequence and the 2D-GRE sequence was evaluated with 2 identical injections of co-hyperpolarized [1-13 C]pyruvate and [13 C,15 N2 ]urea formula in a rat. Subsequently, the feasibility of the acquisition strategy was validated in a prostate cancer patient. RESULTS: Simulations and phantom studies demonstrated that 3D-bSSFP sequence achieved urea-only excitation, while minimally perturbing other metabolites (<1%). An animal study demonstrated that compared to GRE, bSSFP sequence provided an ∼2.5-fold improvement in SNR without perturbing urea or pyruvate kinetics, and bSSFP approach with a shorter spiral readout reduced blurring artifacts caused by J-coupling of [13 C,15 N2 ]urea. The human study demonstrated the in vivo feasibility and data quality of the acquisition strategy. CONCLUSION: The 3D-bSSFP urea sequence with a stack-of-spiral acquisition demonstrated significantly increased SNR and image quality for [13 C,15 N2 ]urea in co-hyperpolarized [1-13 C]pyruvate and [13 C,15 N2 ]urea imaging studies. This work lays the foundation for future human studies to achieve high-quality and high-SNR metabolism and perfusion images.

Whole-Abdomen Metabolic Imaging of Healthy Volunteers Using Hyperpolarized [1-13 C]pyruvate MRI.

BACKGROUND: Hyperpolarized 13 C MRI quantitatively measures enzyme-catalyzed metabolism in cancer and metabolic diseases. Whole-abdomen imaging will permit dynamic metabolic imaging of several abdominal organs simultaneously in healthy and diseased subjects. PURPOSE: Image hyperpolarized [1-13 C]pyruvate and products in the abdomens of healthy volunteers, overcoming challenges of motion, magnetic field variations, and spatial coverage. Compare hyperpolarized [1-13 C]pyruvate metabolism across abdominal organs of healthy volunteers. STUDY TYPE: Prospective technical development. SUBJECTS: A total of 13 healthy volunteers (8 male), 21-64 years (median 36). FIELD STRENGTH/SEQUENCE: A 3 T. Proton: T1 -weighted spoiled gradient echo, T2 -weighted single-shot fast spin echo, multiecho fat/water imaging. Carbon-13: echo-planar spectroscopic imaging, metabolite-specific echo-planar imaging. ASSESSMENT: Transmit magnetic field was measured. Variations in main magnetic field (ΔB0 ) determined using multiecho proton acquisitions were compared to carbon-13 acquisitions. Changes in ΔB0 were measured after localized shimming. Improvements in metabolite signal-to-noise ratio were calculated. Whole-organ regions of interests were drawn over the liver, spleen, pancreas, and kidneys by a single investigator. Metabolite signals, time-to-peak, decay times, and mean first-order rate constants for pyruvate-to-lactate (kPL ) and alanine (kPA ) conversion were measured in each organ. STATISTICAL TESTS: Linear regression, one-sample Kolmogorov-Smirnov tests, paired t-tests, one-way ANOVA, Tukey's multiple comparisons tests. P ≤ 0.05 considered statistically significant. RESULTS: Proton ΔB0 maps correlated with carbon-13 ΔB0 maps (slope = 0.93, y-intercept = -2.88, R2  = 0.73). Localized shimming resulted in mean frequency offset within ±25 Hz for all organs. Metabolite SNR significantly increased after denoising. Mean kPL and kPA were highest in liver, followed by pancreas, spleen, and kidneys (all comparisons with liver were significant). DATA CONCLUSION: Whole-abdomen coverage with hyperpolarized carbon-13 MRI was feasible despite technical challenges. Multiecho gradient echo 1 H acquisitions accurately predicted chemical shifts observed using carbon-13 spectroscopy. Carbon-13 acquisitions benefited from local shimming. Metabolite energetics in the abdomen compiled for healthy volunteers can be used to design larger clinical trials in patients with metabolic diseases. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 1.

Infectious complications in adult patients with idiopathic minimal change nephrotic syndrome undergoing immunosuppressive therapy.

BACKGROUND: Patients with idiopathic minimal change nephrotic syndrome (MCNS) undergoing immunosuppressive therapy are susceptible to infectious complications. Study specifically focusing on adult population's infectious complications is lacking. METHODS: We retrospectively collected 101 adult patients with biopsy-proven idiopathic MCNS and analysed for the infectious complications. Published literatures were also reviewed aiming to evaluate the feasibility of prophylactic antibiotic treatment. RESULTS: Infectious complications developed in 17 of 101 (16.8%) patients, with pneumonia (n = 4), cellulitis/fasciitis (n = 4) and urinary tract infection (UTI) (n = 4) being the dominant diseases, and Gram-negative bacilli the main cause. AKI stage ≥2 (Hazard ratio = 6.1; 95% CI: 1.2-31.9, p = 0.031) and non-remission by treatment (Hazard ratio = 4.4; 95% CI: 1.2-15.6, p = .023) were the two independent risk factors relevant to developing infectious complications. Review of 16 published literatures and our data showed that even no prophylactic antibiotic therapy, only one case of Pneumocystis jirovecii pneumonia developed among the 1787 accumulative cases of MCNS. In contrast, 16 (44%) of acute flare cases were reported among the 36 patients with positive hepatitis B surface antigen that did not receive antiviral prophylactic therapy. CONCLUSIONS: Advanced acute kidney injury and non-remission by treatment are the risk factors toward developing infectious complications in adult MCNS undergoing immunosuppressive therapy. It appears unnecessary to use prophylactic antibiotic for Pneumocystis jirovecii pneumonia or other bacterial infections, while screening and prophylactic therapy for hepatitis B and latent tuberculosis are critical for patients in prevalent area.

Rare cause of ascites and pleural effusion: The first case report and literature review of pseudo-pseudo Meig's syndrome in Taiwan.

Pseudo-pseudo Meigs' syndrome (PPMS) exhibits patients with ascites, pleural effusion, elevated CA-125, and diagnosed of systemic lupus erythematosus (SLE) eventually without evidence of ovarian or pelvic tumor. It's a rare diagnosis but it has a good response to treatment. We here present an 82-year-old female, who was found to have ascites, pleural effusion, and elevated CA-125. CT of abdomen revealed absence of pelvic tumor. However, a rapid decline in renal function and progressive proteinuria were also observed. We performed an autoimmune-associated investigation. A diagnosis of late-onset SLE was made due to meeting the criteria of serositis, hemolytic anemia, thrombocytopenia, renal disease, and positive anti-smith antibody. We gave this patient a regimen with steroids and hydroxychloroquine. Both ascites and pleural effusion resolved in one month. PPMS is an important differential diagnosis in female patients with ascites, pleural effusion, and elevated CA-125. A survey of the pelvic tumor should be done first to exclude Meigs' syndrome or pseudo-Meigs' syndrome. SLE flare-up should be kept in mind even in the elderly.