Quantitative analysis from ultrafast dynamic contrast-enhanced breast MRI using population-based versus individual arterial input functions, and comparison with semi-quantitative analysis

PURPOSE

To evaluate the value of inline quantitative analysis of ultrafast dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using a population-based arterial input function (P-AIF) compared with offline quantitative analysis with an individual AIF (I-AIF) and semi-quantitative analysis for diagnosing breast cancer.

METHODS

This prospective study included 99 consecutive patients with 109 lesions (85 malignant and 24 benign). Model-based parameters (Ktrans, kep, and ve) and model-free parameters (washin and washout) were derived from CAIPIRINHA-Dixon-TWIST-VIBE (CDTV) DCE-MRI. Univariate analysis and multivariate logistic regression analysis with forward stepwise covariate selection were performed to identify significant variables. The AUC and F1 score were assessed for semi-quantitative and two quantitative analyses.

RESULTS

kep from inline quantitative analysis with P-AIF for diagnosing breast cancer provided an AUC similar to kep from offline quantitative analysis with I-AIF (0.782 vs 0.779, p = 0.954), higher compared to washin from semi-quantitative analysis (0.782 vs 0.630, p = 0.034). Furthermore, the inline quantitative analysis with P-AIF achieved the larger F1 score (0.920) compared with offline quantitative analysis with I-AIF (0.780) and semi-quantitative analysis (0.480). There were no statistically significant differences for kep values between the two quantitative analysis schemes (p = 0.944).

CONCLUSION

The inline quantitative analysis with P-AIF from CDTV in characterizing breast lesions could offer similar diagnostic accuracy to offline quantitative analysis with I-AIF, and higher diagnostic accuracy to semi-quantitative analysis.

Tislelizumab, a novel PD-1 monoclonal antibody in urothelial cancer: A real-world study

OBJECTIVE

Tislelizumab, a monoclonal antibody against programed death protein-1 (PD-1), has shown encouraging antitumor activity in urothelial cancer. This study was designed to assess the efficacy and safety of tislelizumab in urotelial cancer in a real-world setting.

METHODS

The study was a real-world retrospective study undertaken at Liaoning Cancer Hospital & Institute, China. Eligible patients were ≥18 years. Patients received 200-mg tislelizumab monotherapy intravenously every 3 weeks until the disease progressed to intolerable toxicity. Outcomes included an objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and safety.

RESULTS

Between March 2020 and December 2022, 33 patients were enrolled. The median follow-up was 10.17 (IQR 5.73-12.47) months. Of all 33 patients, ORR and DCR were 30.30% (95% CI 15.6%-48.7%) and 42.42% (95% CI 25.48%-60.78%), respectively. The median PFS was 5.73 (95% CI 3.27-13.00) months, with a 12-month PFS rate of 31.90% (95% CI 19.20%-53.00%). The median OS was 17.7 (95% CI 12.80-not reach) months, with a 12-month OS rate of 67.50% (95% CI 52.70%-86.40%). Eleven (33.33%) and 8 (24.24%) experienced ≥grade 3 treatment-related adverse events (TRAEs) and immune-related Aes, respectively. No treatment-related deaths occurred.

CONCLUSION

The excellent efficacy and controllable safety of tislelizumab in locally advanced or metastatic urothelial cancer suggest that it may be a promising therapeutic option for this population.

Multi-task reconstruction network for synthetic diffusion kurtosis imaging: Predicting neoadjuvant chemoradiotherapy response in locally advanced rectal cancer

PURPOSE

To assess the feasibility and clinical value of synthetic diffusion kurtosis imaging (DKI) generated from diffusion weighted imaging (DWI) through multi-task reconstruction network (MTR-Net) for tumor response prediction in patients with locally advanced rectal cancer (LARC).

METHODS

In this retrospective study, 120 eligible patients with LARC were enrolled and randomly divided into training and testing datasets with a 7:3 ratio. The MTR-Net was developed for reconstructing Dapp and Kapp images from apparent diffusion coefficient (ADC) images. Tumor regions were manually segmented on both true and synthetic DKI images. The synthetic image quality and manual segmentation agreement were quantitatively assessed. The support vector machine (SVM) classifier was used to construct radiomics models based on the true and synthetic DKI images for pathological complete response (pCR) prediction. The prediction performance for the models was evaluated by the receiver operating characteristic (ROC) curve analysis.

RESULTS

The mean squared error (MSE), peak signal-to-noise ratio (PSNR), and structural similarity index measure (SSIM) for tumor regions were 0.212, 24.278, and 0.853, respectively, for the synthetic Dapp images and 0.516, 24.883, and 0.804, respectively, for the synthetic Kapp images. The Dice similarity coefficient (DSC), positive predictive value (PPV), sensitivity (SEN), and Hausdorff distance (HD) for the manually segmented tumor regions were 0.786, 0.844, 0.755, and 0.582, respectively. For predicting pCR, the true and synthetic DKI-based radiomics models achieved area under the curve (AUC) values of 0.825 and 0.807 in the testing datasets, respectively.

CONCLUSIONS

Generating synthetic DKI images from DWI images using MTR-Net is feasible, and the efficiency of synthetic DKI images in predicting pCR is comparable to that of true DKI images.

Establishment and evaluation of rat models of parastomal hernia

PURPOSE

Parastomal hernia poses a challenging problem in the field of hernia surgery. The high incidence and recurrence rates of parastomal hernia necessitate surgeons to enhance surgical techniques and repair materials. This study aimed to develop a rat model of parastomal hernia by inducing various types of defects on the abdominal wall with colostomy. This established method has potential for future studies on parastomal hernia.

METHODS

In this study, 32 male rats were included and randomly divided into four groups: the oblique abdominis excision (OE), oblique abdominis dissection (OD), rectus abdominis excision (RE), and rectus abdominis dissection (RD) groups. In each group, colostomy was performed and an abdominal wall defect was induced. The rats were observed for 28 days following surgery. The survival rate, body weight, parastomal hernia model scores, abdominal wall adhesion and inflammation, and collagen level in the hernial sac were compared.

RESULTS

No significant differences in survival rate and weight were observed among the four groups. The parastomal hernia model scores in the RE and RD groups were significantly higher than those in the OE and OD groups. The ratio of collagen I/III in the RE and RD groups was significantly lower than that in the OE and OD groups. Adhesion and inflammation levels were lower in the RE group than in the RD group.

CONCLUSION

Based on a comprehensive comparison of the findings, RE with colostomy emerged as the optimal approach for establishing parastomal hernia models in rats.

Deep learning reconstruction for turbo spin echo to prospectively accelerate ankle MRI: A multi-reader study

PURPOSE

To evaluate a deep learning reconstruction for turbo spin echo (DLR-TSE) sequence of ankle magnetic resonance imaging (MRI) in terms of acquisition time, image quality, and lesion detectability by comparing with conventional TSE.

METHODS

Between March 2023 and May 2023, patients with an indication for ankle MRI were prospectively enrolled. Each patient underwent a conventional TSE protocol and a prospectively undersampled DLR-TSE protocol. Four experienced radiologists independently assessed image quality using a 5-point scale and reviewed structural abnormalities. Image quality assessment included overall image quality, differentiation of anatomic details, diagnostic confidence, artifacts, and noise. Interchangeability analysis was performed to evaluate the equivalence of DLR-TSE relative to conventional TSE for detection of structural pathologies.

RESULTS

In total, 56 patients were included (mean age, 32.6 ± 10.6 years; 35 men). The DLR-TSE (233 s) protocol enabled a 57.4 % reduction in total acquisition time, compared with the conventional TSE protocol (547 s). DLR-TSE images had superior overall image quality, fewer artifacts, and less noise (all P < 0.05), compared with conventional TSE images, according to mean ratings by the four readers. Differentiation of anatomic details, diagnostic confidence, and assessments of structural abnormalities showed no differences between the two techniques (P > 0.05). Furthermore, DLR-TSE demonstrated diagnostic equivalence with conventional TSE, based on interchangeability analysis involving all analyzed structural abnormalities.

CONCLUSION

DLR can prospectively accelerate conventional TSE to a level comparable with a 4-minute comprehensive examination of the ankle, while providing superior image quality and similar lesion detectability in clinical practice.

Multi-b-value DWI to evaluate the synergistic antiproliferation and anti-heterogeneity effects of bufalin plus sorafenib in an orthotopic HCC model

BACKGROUND

Multi-b-value diffusion-weighted imaging (DWI) with different postprocessing models allows for evaluating hepatocellular carcinoma (HCC) proliferation, spatial heterogeneity, and feasibility of treatment strategies. We assessed synergistic effects of bufalin+sorafenib in orthotopic HCC-LM3 xenograft nude mice by using intravoxel incoherent motion (IVIM), diffusion kurtosis imaging (DKI), a stretched exponential model (SEM), and a fractional-order calculus (FROC) model.

METHODS

Twenty-four orthotopic HCC-LM3 xenograft mice were divided into bufalin+sorafenib, bufalin, sorafenib treatment groups, and a control group. Multi-b-value DWI was performed using a 3-T scanner after 3 weeks' treatment to obtain true diffusion coefficient Dt, pseudo-diffusion coefficient Dp, perfusion fraction f, mean diffusivity (MD), mean kurtosis (MK), distributed diffusion coefficient (DDC), heterogeneity index α, diffusion coefficient D, fractional order parameter β, and microstructural quantity μ. Necrotic fraction (NF), standard deviation (SD) of hematoxylin-eosin staining, and microvessel density (MVD) of anti-CD31 staining were evaluated. Correlations of DWI parameters with histopathological results were analyzed, and measurements were compared among four groups.

RESULTS

In the final 22 mice, f positively correlated with MVD (r = 0.679, p = 0.001). Significantly good correlations of MK (r = 0.677), α (r = -0.696), and β (r= -0.639) with SD were observed (all p < 0.010). f, MK, MVD, and SD were much lower, while MD, α, β, and NF were higher in bufalin plus sorafenib group than control group (all p < 0.050).

CONCLUSION

Evaluated by IVIM, DKI, SEM, and FROC, bufalin+sorafenib was found to inhibit tumor proliferation and angiogenesis and reduce spatial heterogeneity in HCC-LM3 models.

RELEVANCE STATEMENT

Multi-b-value DWI provides potential metrics for evaluating the efficacy of treatment in HCC.

KEY POINTS

• Bufalin plus sorafenib combination may increase the effectiveness of HCC therapy. • Multi-b-value DWI depicted HCC proliferation, angiogenesis, and spatial heterogeneity. • Multi-b-value DWI may be a noninvasive method to assess HCC therapeutic efficacy.

Evaluation of Open Versus Arthroscopic Anterior Talofibular Ligament Reconstruction for Chronic Lateral Ankle Instability With Talar and Subtalar Cartilage MRI T2 Mapping: A 3-Year Prospective Study

BACKGROUND

Previous studies have examined patients with chronic lateral ankle instability (CLAI) undergoing open and arthroscopic anterior talofibular ligament (ATFL) reconstruction, reporting equivalent clinical results between the 2 procedures. However, data on the magnetic resonance imaging (MRI) outcomes on cartilage health after the 2 procedures are limited.

PURPOSE

To compare the cartilage MRI T2 values of the talar and subtalar joints between patients with CLAI undergoing open and arthroscopic ATFL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A prospective study was conducted on patients who underwent open or arthroscopic ATFL reconstruction between January 2018 and December 2019, with a mean follow-up duration of 3 years. MRI scans and American Orthopaedic Foot & Ankle Society (AOFAS) and Tegner score estimations were completed by patients ≤1 week before surgery, as a baseline measurement, and at a 3-year follow-up. A total of 21 healthy volunteers were included who underwent MRI at baseline. Cartilage health was evaluated using MRI T2 mapping. The talar and subtalar cartilage regions were segmented into 14 subregions.

RESULTS

At baseline, patients with CLAI had substantially higher T2 values in the medial anterior, medial center, medial posterior, and lateral center regions on the talus compared with the healthy controls (P = .009, .003, .001, and .025, respectively). Remarkable increases in T2 values in the lateral posterior region on the talus were observed from baseline to follow-up in the open group (P = .007). Furthermore, T2 values were considerably higher in the medial center, medial posterior, lateral posterior, and lateral posterior calcaneal facets of the posterior subtalar joint at follow-up in the arthroscopic group compared with the baseline values (P = .025, .002, .006, and .044, respectively). No obvious differences in ΔT2 values were noted between the 2 groups at follow-up. The AOFAS and Tegner scores remarkably improved from baseline to follow-up for the 2 groups (open: 3.25 ± 0.58 vs 5.13 ± 0.81, P < .001; arthroscopic: 3.11 ± 0.90 vs 5.11 ± 1.08, P < .001), with no considerable difference between them.

CONCLUSION

The elevated T2 values of cartilage could not be fully recovered after open or arthroscopic ATFL reconstruction. Both arthroscopic and open ATFL reconstruction displayed similar effects on cartilage health concerning ΔT2, but the arthroscopic group demonstrated more degenerative cartilage subregions than the open group.

Diffusion-Weighted MRI-Based Virtual Elastography and Shear-Wave Elastography for the Assessment of Breast Lesions

BACKGROUND

Diffusion-weighted imaging (DWI)-based virtual MR elastography (DWI-vMRE) in the assessment of breast lesions is still in the research stage.

PURPOSE

To investigate the usefulness of elasticity values on DWI-vMRE in the evaluation of breast lesions, and the correlation with the values calculated from shear-wave elastography (SWE).

STUDY TYPE

Prospective.

POPULATION/SUBJECTS

153 patients (mean age ± standard deviation: 55 ± 12 years) with 153 pathological confirmed breast lesions (24 benign and 129 malignant lesions).

FIELD STRENGTH/SEQUENCE

1.5-T MRI, multi-b readout segmented echo planar imaging (b-values of 0, 200, 800, and 1000 sec/mm2 ).

ASSESSMENT

For DWI-vMRE assessment, lesions were manually segmented using apparent diffusion coefficient (ADC0-1000 ) map, then the region of interests were copied to the map of shifted-ADC (sADC200-800 , sADC 200-1500 ). For SWE assessment, the shear modulus of the lesions was measured by US elastic modulus (μUSE ). Intraclass/interclass kappa coefficients were calculated to measure the consistency.

STATISTICAL TESTS

Pearson's correlation was used to assess the relationship between sADC and μUSE . A receiver operating characteristic analysis with the area under the curve (AUC) was performed to compare the diagnostic accuracy between benign and malignant breast lesions of sADC and μUSE . A P value <0.05 was considered statistically significant.

RESULTS

There were significant differences between benign and malignant breast lesions of μUSE (24.17 ± 10.64 vs. 37.20 ± 12.61), sADC200-800 (1.38 ± 0.31 vs. 0.97 ± 0.18 × 10-3  mm2 /sec), and sADC200-1500 (1.14 ± 0.30 vs. 0.78 ± 0.13 × 10-3  mm2 /sec). In all breast lesions, a moderate but significant correlation was observed between μUSE and sADC200-800 /sADC200-1500 (r = -0.49/-0.44). AUC values to differentiate benign from malignant lesions were as follows: μUSE , 0.78; sADC200-800 , 0.89; sADC200-1500 , 0.89.

DATA CONCLUSIONS

Both SWE and DWI-vMRE could be used for the differentiation of benign versus malignant breast lesions. Furthermore, DWI-vMRE with the use of sADC show relatively higher AUC values than SWE.

LEVEL OF EVIDENCE

4 TECHNICAL EFFICACY: Stage 2.

Toripalimab plus axitinib versus sunitinib as first-line treatment for advanced renal cell carcinoma: RENOTORCH, a randomized, open-label, phase III study

BACKGROUND

Immune checkpoint inhibitors in combination with tyrosine kinase inhibitors are standard treatments for advanced clear cell renal cell carcinoma (RCC). This phase III RENOTORCH study compared the efficacy and safety of toripalimab plus axitinib versus sunitinib for the first-line treatment of patients with intermediate-/poor-risk advanced RCC.

PATIENTS AND METHODS

Patients with intermediate-/poor-risk unresectable or metastatic RCC were randomized in a ratio of 1 : 1 to receive toripalimab (240 mg intravenously once every 3 weeks) plus axitinib (5 mg orally twice daily) or sunitinib [50 mg orally once daily for 4 weeks (6-week cycle) or 2 weeks (3-week cycle)]. The primary endpoint was progression-free survival (PFS) assessed by an independent review committee (IRC). The secondary endpoints were investigator-assessed PFS, overall response rate (ORR), overall survival (OS), and safety.

RESULTS

A total of 421 patients were randomized to receive toripalimab plus axitinib (n = 210) or sunitinib (n = 211). With a median follow-up of 14.6 months, toripalimab plus axitinib significantly reduced the risk of disease progression or death by 35% compared with sunitinib as assessed by an IRC [hazard ratio (HR) 0.65, 95% confidence interval (CI) 0.49-0.86; P = 0.0028]. The median PFS was 18.0 months in the toripalimab-axitinib group, whereas it was 9.8 months in the sunitinib group. The IRC-assessed ORR was significantly higher in the toripalimab-axitinib group compared with the sunitinib group (56.7% versus 30.8%; P < 0.0001). An OS trend favoring toripalimab plus axitinib was also observed (HR 0.61, 95% CI 0.40-0.92). Treatment-related grade ≥3 adverse events occurred in 61.5% of patients in the toripalimab-axitinib group and 58.6% of patients in the sunitinib group.

CONCLUSION

In patients with previously untreated intermediate-/poor-risk advanced RCC, toripalimab plus axitinib provided significantly longer PFS and higher ORR than sunitinib and had a manageable safety profile TRIAL REGISTRATION: ClinicalTrials.gov NCT04394975.

A double-tuned 1 H/31 P coil for rabbit heart metabolism detection at 3 T

Magnetic resonance imaging (MRI)/magnetic resonance spectroscopy (MRS) employing proton nuclear resonance has emerged as a pivotal modality in clinical diagnostics and fundamental research. Nonetheless, the scope of MRI/MRS extends beyond protons, encompassing nonproton nuclei that offer enhanced metabolic insights. A notable example is phosphorus-31 (31 P) MRS, which provides valuable information on energy metabolites within the skeletal muscle and cardiac tissues of individuals affected by diabetes. This study introduces a novel double-tuned coil tailored for 1 H and 31 P frequencies, specifically designed for investigating cardiac metabolism in rabbits. The proposed coil design incorporates a butterfly-like coil for 31 P transmission, a four-channel array for 31 P reception, and an eight-channel array for 1 H reception, all strategically arranged on a body-conformal elliptic cylinder. To assess the performance of the double-tuned coil, a comprehensive evaluation encompassing simulations and experimental investigations was conducted. The simulation results demonstrated that the proposed 31 P transmit design achieved acceptable homogeneity and exhibited comparable transmit efficiency on par with a band-pass birdcage coil. In vivo experiments further substantiated the coil's efficacy, revealing that the rabbit with experimentally induced diabetes exhibited a lower phosphocreatine/adenosine triphosphate ratio compared with its normal counterpart. These findings emphasize the potential of the proposed coil design as a promising tool for investigating the therapeutic effects of novel diabetes drugs within the context of animal experimentation. Its capability to provide detailed metabolic information establishes it as an indispensable asset within this realm of research.

Ambient Phosphor with High Efficiency and Long Lifetime in Poly(Methyl Methacrylate) Through Charge-Transfer-Mediated Triplet Exciton Formation for Photolithography Applications

Currently, purely organic compounds showing ambient phosphorescence with high efficiency (ΦP ) and ultra-long lifetime (τP ) are quite rare and often need to be achieved in hydrophilic poly(vinyl alcohol)-based hosts. This severely limits their applications. Here, we provide a solution to this issue by constructing an ortho-linked donor-acceptor (D-A) dyad whose D moiety has not only a long-lived T1 state to achieve a long τP , but also a Tn state that is close to the S1 state of the dyad to trigger effective spin-orbit charge transfer intersystem crossing (SOCT-ISC). The rationality of this strategy was validated by a new phosphor OF-BCz that is able to show a τP of 1.92 s and a ΦP of 30 % even in a less rigid matrix of poly(methyl methacrylate) (PMMA). Excitingly, OF-BCz exhibited its potential as both a photocuring initiator and an in situ quality indicator, allowing for the visual detection of defects in photolithographic patterning.

Isomeric Effect of a π Bridge in an IDT-Based Nonfused Electron Photovoltaic Acceptor

A pair of isomers, IDT-BOF containing S⋅⋅⋅O/F⋅⋅⋅H noncovalently configurational locks and IDT-BFO containing F⋅⋅⋅H/O⋅⋅⋅H noncovalently configurational locks, with an acceptor-π-donor-π-acceptor (A-π-D-π-A) structure have been designed and synthesized by choosing 4,9-dihydro-s-indaceno[1,2-b : 5,6-b']dithiophene (IDT) as the D unit, an F/n-hexyloxy substituted phenyl ring as π bridge, and 3-(dicyanomethylidene)indan-1-one as the A unit. Owing to the S⋅⋅⋅O/F⋅⋅⋅H or F⋅⋅⋅H/O⋅⋅⋅H noncovalently configurational locks, both IDT-BOF and IDT-BFO have a completely planar structure. IDT-BOF exhibits a similar LUMO to IDT-BFO, but higher HOMO energy levels, leading to a smaller optical bandgap and red-shifted absorption. However, IDT-BOF-based bulk-heterojunction organic solar cells (BHJ-OSCs) coupled with PBDB-T, and PCE-10 as donor materials both exhibited a lower PCE than that of IDT-BFO (PBDB-T: 5.2 vs. 6.1 %; PCE-10: 1.7 vs. 3.2 %). Comprehensively comparing and investigating IDT-BOF : PBDB-T and IDT-BFO : PBDB-T OSCs suggested that the large phase separation and serious charge recombination of IDT-BOF-based OSCs contributed to its lower power conversion efficiency. Importantly, ternary solar cells based on PBDB-T : Y5 as control devices with an additional 10 % IDT-BFO exhibited a 5 % enhancement in the PCE compared to the control device (14.3 vs. 13.46 %).

Acquiring Charge-Transfer-Featured Single-Molecule Ultralong Organic Room Temperature Phosphorescence via Through-Space Electronic Coupling

Although long-lived triplet charge-transfer (3 CT) state with high energy level has gained significant attention, the development of organic small molecules capable of achieving such states remains a major challenge. Herein, by using the through-space electronic coupling effect, we have developed a compound, namely NIC-DMAC, which has a long-lived 3 CT state at the single-molecule level with a lifetime of 210 ms and a high energy level of up to 2.50 eV. Through a combination of experimental and computational approaches, we have elucidated the photophysical processes of NIC-DMAC, which involve sequential transitions from the first singlet excited state (S1 ) that shows a 1 CT character to the first triplet excited state (T1 ) that exhibits a local excited state feature (3 LE), and then to the second triplet excited state (T2 ) that shows a 3 CT character (i.e., S1 (1 CT)→T1 (3 LE)→T2 (3 CT)). The long lifetime and high energy level of its 3 CT state have enabled NIC-DMAC as an initiator for photocuring in double patterning applications.

Whole tumor based texture analysis of magnetic resonance diffusion imaging for colorectal liver metastases: A prospective study for diffusion model comparison and early response biomarker

PURPOSE

To evaluate and compare the diagnostic value of diffusion-related texture analysis parameters obtained from various magnetic resonance diffusion models as early predictors of the clinical response to chemotherapy in patients with colorectal liver metastases (CRLM).

METHODS

Patients (n = 145) with CRLM were prospectively and consecutively enrolled and scanned using diffusion-weighted imaging (DWI)-magnetic resonance imaging (MRI)/intravoxel incoherent motion (IVIM)/diffusion kurtosis imaging (DKI) before (baseline) and two-three weeks after (follow-up) commencing chemotherapy. Therapy response was evaluated based on the Response Evaluation Criteria in Solid Tumors (RECIST, version 1.1). The histogram and texture parameters of each diffusion-related parametric map were analysed between the responding and non-responding groups, screened using LASSO, and fitted with binary logistic regression models. The diagnostic efficacy of each model in the early prediction of CRLM was analysed, and the corresponding receiver operating characteristic (ROC) curve was drawn. The area under the curve (AUC) and 95% confidence intervals (CI) were calculated.

RESULTS

Of the 145 analysed patients, 69 were in the responding group and 76 were in the non-responding group. Among all models, the difference value based on the histogram and texture features of the DKI-derived parameters performed best for the early prediction of CRLM treatment efficacy. The AUC of the DKI model in the validation set reached 0.795 (95% CI 0.652-0.938). Among the IVIM-derived parameters, the difference model based on D and D* performed best, and the AUC in the validation set reached 0.737 (95% CI 0.586-0.889). Finally, in the DWI sequence, the model comprising baseline features performed the best, with an AUC of 0.699 (95% CI 0.537-0.86) in the validation set.

CONCLUSIONS

Baseline DWI parameters and follow-up changes in IVIM and DKI parameters predicted the chemotherapeutic response in patients with CRLM. In addition, as very early predictors, DKI-derived parameters were more effective than DWI- and IVIM-related parameters, in which changes in D-parameters performed best.

Prospective Comparison of Standard and Deep Learning-reconstructed Turbo Spin-Echo MRI of the Shoulder

Background Deep learning (DL)-based MRI reconstructions can reduce imaging times for turbo spin-echo (TSE) examinations. However, studies that prospectively use DL-based reconstructions of rapidly acquired, undersampled MRI in the shoulder are lacking. Purpose To compare the acquisition time, image quality, and diagnostic confidence of DL-reconstructed TSE (TSEDL) with standard TSE in patients indicated for shoulder MRI. Materials and Methods This prospective single-center study included consecutive adult patients with various shoulder abnormalities who were clinically referred for shoulder MRI between February and March 2023. Each participant underwent standard TSE MRI (proton density- and T1-weighted imaging; conventional TSE sequence was used as reference for comparison), followed by a prospectively undersampled accelerated TSEDL examination. Six musculoskeletal radiologists evaluated images using a four-point Likert scale (1, poor; 4, excellent) for overall image quality, perceived signal-to-noise ratio, sharpness, artifacts, and diagnostic confidence. The frequency of major pathologic features and acquisition times were also compared between the acquisition protocols. The intergroup comparisons were performed using the Wilcoxon signed rank test. Results Overall, 135 shoulders in 133 participants were evaluated (mean age, 47.9 years ± 17.1 [SD]; 73 female participants). The median acquisition time of the TSEDL protocol was lower than that of the standard TSE protocol (288 seconds [IQR, 288-288 seconds] vs 926 seconds [IQR, 926-950 seconds], respectively; P < .001), achieving a 69% lower acquisition time. TSEDL images were given higher scores for overall image quality, perceived signal-to-noise ratio, and artifacts (all P < .001). Similar frequency of pathologic features (P = .48 to > .99), sharpness (P = .06), or diagnostic confidence (P = .05) were noted between images from the two protocols. Conclusion In a clinical setting, TSEDL led to reduced examination time and higher image quality with similar diagnostic confidence compared with standard TSE MRI in the shoulder. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Chang and Chow in this issue.

Computed Diffusion-Weighted Images of Rectal Cancer: Image Quality, Restaging, and Treatment Response after Neoadjuvant Therapy

BACKGROUND

Computed diffusion-weighted images (cDWI) of random b value could be derived from acquired DWI (aDWI) with at least two different b values. However, its comparison between aDWI and cDWI images in locally advanced rectal cancer (LARC) patients after neoadjuvant therapy (NT) is needed.

PURPOSE

To compare the cDWI and aDWI in image quality, restaging, and treatment response of LARC after NT.

STUDY TYPE

Retrospective.

POPULATION

Eighty-seven consecutive patients.

FIELD STRENGTH/SEQUENCE

3.0 T/DWI.

ASSESSMENT

All patients underwent two DWI sequences, including conventional acquisition with b = 0 and 1000 s/mm2 (aDWIb1000 ) and another with b = 0 and 700 s/mm2 on a 3.0-T MR scanner. The images of the latter were used to compute the diffusion images with b = 1000 s/mm2 (cDWIb1000 ). Four radiologists with 3, 4, 14, and 25 years of experience evaluated the images to compare the image quality, TN restaging performance, and treatment response between aDWIb1000 and cDWIb1000 .

STATISTICAL TESTS

Interclass correlation coefficients, weighted κ coefficient, paired Wilcoxon, and McNemar or Fisher test were used. A significance level of 0.05 was used.

RESULTS

The cDWIb1000 images were superior to the aDWIb1000 ones in both subjective and objective image quality. In T restaging, the overall diagnostic accuracy of cDWIb1000 images was higher than that of aDWIb1000 images (57.47% vs. 49.43%, P = 0.289 for the inexperienced radiologist; 77.01% vs. 63.22%, significant for the experienced radiologist), with better sensitivity in determining ypT0-Tis tumors. Additionally, it increased the sensitivity in detecting ypT2 tumors for the inexperienced radiologist and ypT3 tumors for the experienced radiologist. N restaging and treatment response were found to be similar between two sequences for both radiologists.

DATA CONCLUSION

Compared to aDWIb1000 images, the computed ones might serve as a wise approach, providing comparable or better image quality, restaging performance, and treatment response assessment for LARC after NT.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 2.

Machine-learning-based performance comparison of two-dimensional (2D) and three-dimensional (3D) CT radiomics features for intracerebral haemorrhage expansion

AIM

To investigate the value of non-contrast CT (NCCT)-based two-dimensional (2D) radiomics features in predicting haematoma expansion (HE) after spontaneous intracerebral haemorrhage (ICH) and compare its predictive ability with the three-dimensional (3D) signature.

MATERIALS AND METHODS

Three hundred and seven ICH patients who received baseline NCCT within 6 h of ictus from two stroke centres were analysed retrospectively. 2D and 3D radiomics features were extracted in the manner of one-to-one correspondence. The 2D and 3D models were generated by four different machine-learning algorithms (regularised L1 logistic regression, decision tree, support vector machine and AdaBoost), and the receiver operating characteristic (ROC) curve was used to compare their predictive performance. A robustness analysis was performed according to baseline haematoma volume.

RESULTS

Each feature type of 2D and 3D modalities used for subsequent analyses had excellent consistency (mean ICC >0.9). Among the different machine-learning algorithms, pairwise comparison showed no significant difference in both the training (mean area under the ROC curve [AUC] 0.858 versus 0.802, all p>0.05) and validation datasets (mean AUC 0.725 versus 0.678, all p>0.05), and the 10-fold cross-validation evaluation yielded similar results. The AUCs of the 2D and 3D models were comparable either in the binary or tertile volume analysis (all p>0.5).

CONCLUSION

NCCT-derived 2D radiomics features exhibited acceptable and similar performance to the 3D features in predicting HE, and this comparability seemed unaffected by initial haematoma volume. The 2D signature may be preferred in future HE-related radiomic works given its compatibility with emergency condition of ICH.

Value of T1 Mapping in the Non-invasive Assessment of Renal Pathologic Injury for Chronic Kidney Disease Patients

PURPOSE

The objective of this study was to evaluate renal function and pathologic injury in chronic kidney disease (CKD) using T1 mapping.

METHODS

We recruited fifteen healthy volunteers (HV) and seventy-five CKD patients to undergo T1 mapping examination, and renal parenchymal T1 values were measured. Spearman correlation analysis was used to evaluate the relevance between the pathologic injury score, estimated glomerular filtration rate (eGFR), and renal parenchymal T1 values. The diagnostic efficiency of T1 value in evaluating renal pathologic impairment was assessed.

RESULTS

In all subjects, renal cortical T1 value was remarkably lower than renal medullary T1 value (P < 0.01). The renal medullary T1 value of HV was considerably lower than that of CKD patients in all stages (P < 0.05). The T1 values were negatively correlated with eGFR (cortex, r = -0.718; medulla, r = -0.645). The T1 values were positively correlated with glomerular injury score (cortex, r = 0.692; medulla, r = 0.632), tubulointerstitial injury score (cortex, r = 0.758; medulla, r = 0.690) (all P < 0.01). The area under the curve (AUC) of renal cortical and medullary T1 values were 0.914 and 0.880 to distinguish moderate-severe from mild renal injury groups. To differentiate mild renal injury group from control group, the AUC values of renal cortical and medullary T1 values were 0.879 and 0.856.

CONCLUSION

T1 mapping has potential application value in non-invasively assessing renal pathologic injury in CKD.

Magnetic susceptibility and R2*-based texture analysis for evaluating liver fibrosis in chronic liver disease

PURPOSE

To explore potential feasibility of texture features in magnetic susceptibility and R2* maps for evaluating liver fibrosis.

METHODS

Thirty-one patients (median age 46 years; 22 male) with chronic liver disease were prospectively recruited and underwent magnetic resonance imaging (MRI), blood tests, and liver biopsy. Susceptibility and R2* maps were obtained using a 3-dimensional volumetric interpolated breath-hold examination sequence with a 3T MRI scanner. Texture features, including histogram, gray-level co-occurrence matrix (GLCM), gray-level dependence matrix (GLDM), gray-level run length matrix (GLRLM), gray-level size zone matrix (GLSZM), and neighboring gray tone difference matrix (NGTDM) features, were extracted. Texture features and blood test results of non-significant (Ishak-F < 3) and significant fibrosis patients (Ishak-F ≥ 3) were compared, and correlations with Ishak-F stages were analyzed. Areas under the curve (AUCs) were calculated to determine the efficacy for evaluating liver fibrosis.

RESULTS

Nine texture features of susceptibility maps and 19 features of R2* maps were significantly different between non-significant and significant fibrosis groups (all P < 0.05). Large dependence high gray-level emphasis (LDHGLE) of GLDM and long run high gray-level emphasis (LRHGLE) of GLRLM in R2* maps showed significantly negative and good correlations with Ishak-F stages (r = -0.616, P < 0.001; r = -0.637, P < 0.001). Busyness (NGTDM) in susceptibility maps, LDHGLE of GLDM and LRHGLE of GLRLM in R2* maps yield the highest AUCs (AUC = 0.786, P = 0.007; AUC = 0.807, P = 0.004; AUC = 0.819, P = 0.003).

CONCLUSION

Texture characteristics of susceptibility and R2* maps revealed possible staging values for liver fibrosis. Susceptibility and R2*-based texture analysis may be a useful and noninvasive method for staging liver fibrosis.

MR Diffusion Kurtosis Imaging (DKI) of the Normal Human Uterus in Vivo During the Menstrual Cycle

BACKGROUND

The uterus undergoes dynamic changes throughout the menstrual cycle. Diffusion kurtosis imaging (DKI) is based on the non-Gaussian distribution of water molecules and can perhaps represent the changes of uterine microstructure.

PURPOSE

To investigate the temporal changes in DKI-parameters of the normal uterine corpus and cervix during the menstrual cycle.

STUDY TYPE

Prospective.

POPULATION

21 healthy female volunteers (26.64 ± 4.72 years) with regular menstrual cycles (28 ± 7 days).

FIELD STRENGTH/SEQUENCE

Readout segmentation of long variable echo-trains (RESOLVE)-based DKI and fast spin-echo T2-weighted sequences at 3.0T.

ASSESSMENT

Each volunteer was scanned during the menstrual phase, ovulatory phase, and luteal phase. Regions of interest (ROI) were manually delineated in the endometrium, junctional zone, and myometrium of the uterine body, and in the mucosal layer, fibrous stroma layer, and loose stroma layer of the cervix. The mean Kapp (diffusion kurtosis coefficient), Dapp (diffusion coefficient), and ADC (apparent diffusion coefficient) values were measured in the ROI.

STATISTICAL TESTS

ANOVA with Bonferroni or Tamhane correction. Intraclass correlation coefficient (ICC) for assessing agreement. P < 0.05 was considered statistically significant.

RESULTS

During the menstrual cycle, the highest Kapp (0.848 ± 0.184) and lowest Dapp (1.263 ± 0.283 *10-3  mm2 /sec) values were found in the endometrium during the menstrual phase. The Dapp values for the myometrium were significantly higher than those of the endometrium and the junctional zone in every phase. Meanwhile, the Dapp values for the three zonal structures of the cervix during ovulation were significantly higher than those during the luteal phase. However, there was no significant difference in the ADC values of the loose stroma between ovulation and the luteal phase (P = 0.568). The reproducibility of DKI parameters was good (ICC, 0.857-0.944).

DATA CONCLUSION

DKI can show dynamic changes of the normal uterus during the menstrual cycle.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

Hyperon Polarization along the Beam Direction Relative to the Second and Third Harmonic Event Planes in Isobar Collisions at sqrt[s_{NN}]=200 GeV

The polarization of Λ and Λ[over ¯] hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru+Ru and Zr+Zr collisions at sqrt[s_{NN}]=200  GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial density fluctuations. The amplitudes of the sine modulation for the second and third harmonic results are comparable in magnitude, increase from central to peripheral collisions, and show a mild p_{T} dependence. The azimuthal angle dependence of the polarization follows the vorticity pattern expected due to elliptic and triangular anisotropic flow, and qualitatively disagrees with most hydrodynamic model calculations based on thermal vorticity and shear induced contributions. The model results based on one of existing implementations of the shear contribution lead to a correct azimuthal angle dependence, but predict centrality and p_{T} dependence that still disagree with experimental measurements. Thus, our results provide stringent constraints on the thermal vorticity and shear-induced contributions to hyperon polarization. Comparison to previous measurements at RHIC and the LHC for the second-order harmonic results shows little dependence on the collision system size and collision energy.

Salt tide affecting algae-laden micropolluted surface water treatment and membrane performance based on BDD electro-oxidation coupled with ceramic membrane process

Harmful algal blooms pose an emerging threat to freshwater ecological security and human health, necessitating further study in offshore areas. In this work, boron-doped diamond electro-oxidation (BDD/EO) coupled with a ceramic membrane filtration was employed aiming to assess the salt tide affecting algae-laden water treatment involving with various natural organic matters (e.g., HA, SA, and BSA). The results have demonstrated that BDD/EO remove chlorophyll from the algae-laden water effectively due to the inactivation of algal cells. Moreover, considering the influence of salt tide, NH3-N would be mainly oxidized through the in-situ generated active chlorine at the electrode-liquid interface. In addition, in three kinds of salt tide affecting algae-laden water, TOC content in BSA group was decreasing remarkably after BDD/EO with TOC removal efficiency above 80%; while those in HA and SA groups had no obvious reducing due to the more algae cells breakage synchronous with HA and SA removal. Based on the fluorescent characteristics and particle size distribution, the generated small molecular organics after electro-oxidation might raise the pore blockage probability and the hydrophobic organic and fluorescent substances were preferentially oxidized in BDD/EO process being beneficial to reducing membrane fouling. Besides, the membrane special flux in three groups were decreasing significantly and the irreversible fouling resistance in SA group accounted for a larger proportion of the total resistance than those of HA and BSA. At last, in BDD/EO-CM process, macromolecular substances degradation rate was greater than that of small molecules based on the molecular weight distribution in three groups of salt tide affected algae-laden water treatment. In a word, this work provides effective and innovative strategies for the harmful algal bloom control and contributes interesting insights of membrane fouling performance of electrochemical coupled ultrafiltration membrane process.

Deep Learning for Automated Contouring of Primary Gross Tumor Volumes by MRI for Radiation Therapy of Brain Metastasis

PURPOSE/OBJECTIVE(S)

Radiotherapy is one of the most effective methods for the treatment of brain metastases (BMs). Traditional manual delineation of primary gross tumor volumes (GTV) of multiple BMs (especially small metastases) in radiotherapy practice is extremely labor intensive and highly dependent on oncologists' experience, achieving the precise and efficient automatic delineation of BMs is of great significance for efficient and homogeneous one-stop adaptive radiotherapy.

MATERIALS/METHODS

We retrospectively collected 62 MRI (non-enhanced T1-weighted sequences) sequences of 50 patients with BMs from January 2020 to July 2021. An automatic model (BUC-Net) for automatic delineation BMs was proposed in this work, which was based on deep learning by combining 3D bottler layer module and the cascade architecture to improve the accuracy and efficient of BMs' automatic delineation, especially for small metastases with tiny size and relatively low contrast. The prosed method was compared with the existing 3D U-Net (U-Net) and 3D U-Net Cascade (U-Net Cascade). The performance of our proposed method was evaluated by Dice similarity coefficient (DSC), 95% Hausdorff distance (HD95) and average surface distance (ASD) with human experts.

RESULTS

The automatic segmentation results of BUC-Net evaluated with 310 BMs in 13 test patients was summarized in Table 1. These BMs in each test patient were automatically delineated by two types of contours: as a whole tumor contour (Whole-delineation) and the multiple tumor contours (Multiple-delineation). BUC-Net performed the best mean DSC and HD95, which is significantly outperformed U-Net (Whole-delineation: 0.911 & 0.894 of DSC, Multiple-delineation: 0.794 & 0.754 of DSC, P < 0.05 for both) and U-Net cascade (Whole-delineation: 0.947 & 7.141 of HD95, Multiple-delineation: 0.902 & 1.171 of HD95, P < 0.05 for both); Additionally, BUC-Net achieved the best mean ASD for Whole-delineation and comparable ASD (0.290 & 0.277, P > 0) for Multiple-delineation with U-Net Cascade.

CONCLUSION

Our results showed that the proposed approach is promising for the automatic delineation of BMs in MRI, which can be integrated into a radiotherapy workflow to significantly shorten segmentation time.

Magnetic Resonance Imaging-guided Focused Ultrasound Surgery in a Swine Adenomyosis Model

RATIONALE AND OBJECTIVES

The purpose of this study was to explore the feasibility of magnetic resonance imaging-guided focused ultrasound surgery (MRgFUS) for the treatment of an adenomyosis model of Bama pigs and the changes in the level of oxytocin receptor (OTR), vascular endothelial growth factor (VEGF), and cyclooxygenase-2 (COX-2) in the myometrium tissues of Bama pigs after MRgFUS.

MATERIALS AND METHODS

Three Bama pig models of adenomyosis were established by autologous endometrial implantation and evaluated by magnetic resonance imaging, computed tomography, and hematoxylin-eosin (H&E) staining. After the successful construction of the model, the pigs underwent MRgFUS. Before the modeling surgery, three months after the modeling, and two months after ablation, the myometrium tissues were clipped, then embedded and H&E stained for immunohistochemical examination. The average optical density of OTR, VEGF, and COX-2 were semi-quantitatively analyzed.

RESULTS

The adenomyosis models were established in all Bama pigs and confirmed by magnetic resonance imaging, computed tomography and H&E staining. Magnetic resonance imaging and computed tomography examination showed that the uterine wall at the modeling site was significantly thickened with uneven enhancement after contrast injection. All Bama pigs with adenomyosis lesions underwent MRgFUS without complications. The expression level of OTR and COX-2 in the myometrium increased three months after modeling surgery and decreased two months after MRgFUS. The expression level of VEGF decreased two months after MRgFUS.

CONCLUSION

Autologous endometrial implantation is effective in establishing the adenomyosis model of Bama pigs. It is feasible to treat adenomyosis in the Bama pig model with MRgFUS. The levels of OTR, COX-2 and VEGF in the local myometrium decreased after MRgFUS, which may be associated with symptom relief after treatment.

Endometriosis-targeted MRI imaging using bevacizumab-modified nanoparticles aimed at vascular endothelial growth factor

Endometriosis is a tumor-like disease with high recurrence. In this case, the accurate imaging-based diagnosis of endometriosis can help clinicians eradicate it by improving their surgical plan. However, although contrast agents can improve the visibility of the tissue of interest in vivo via magnetic resonance imaging (MRI), the lack of biomarkers in endometriosis hinders the development of agents for its targeted imaging and diagnosis. Herein, aiming at the enriched vascular endothelial growth factor (VEGF) in endometriosis, we developed a targeting MRI contrast agent modified with bevacizumab, i.e., NaGdF₄@PEG@bevacizumab-Cy5.5 nanoparticles (NPBCNs), to detect endometriosis. NPBCNs showed negligible cytotoxicity and high affinity towards VEGF in endometrial cells in vitro. Furthermore, NPBCNs generated a strong signal enhancement in vivo in endometriosis lesions in rats in T₁-weighted images via MRI at 3 days post-injection, as confirmed by the histopathological staining results and fluorescence imaging on the same day. Our approach can enable NPBCNs to target endometriosis effectively, thus avoiding missed diagnoses.

Variabilities in apparent diffusion coefficient (ADC) measurements of the spleen and the paraspinal muscle: A single center large cohort study

Purpose

Evaluation of the variabilities in apparent diffusion coefficient (ADC) measurements of the spleen (ADC_spleen) and the paraspinal muscles (ADC_muscle) to identify the reference organ for normalizing the ADC from the abdominal diffusion weighted imaging (DWI).

Methods

Two MRI scanners, with 314 abdominal exams on the GE and 929 on the Siemens system, were used for MRI examinations including DWI (b-values, 50 and 800 s/mm²). For a subset of 73 exams on the Siemens system a second exam was conducted. Four regions of interest (ROIs) in each exam were placed to measure the ADC_spleen and the bilateral ADC_muscle. ADC variability between patients (on each scanner separately), ADC variability due to ROI placement between the two ROIs in each organ, and variability in the subset between the first and second exams were assessed.

Results

The ADC_spleen was more scattered and variable than the ADC_muscle in the comparability (n = 929 and 314 for two MRI scanners, respectively) and repeatability (n = 73) datasets. The Bland-Altmann bias and limits of agreement (LoAs) for the ADC_spleen (ICC, 0.47; CV, 0.070) and ADC_muscle (ICC, 0.67; CV, 0.023) in the repeatability datasets (n = 73) were -0.1 (-25.7%-25.6%) and -0.3 (-8.8%-8.1%), respectively. For the Siemens system, the Bland-Altmann bias and LoAs for the ADC_spleen (ICC, 0.72; CV, 0.061) and ADC_muscle (ICC, 0.53; CV, 0.030) in the comparability datasets (n = 929) were 2.1 (-20.0%-24.2%) and 0.7 (-10.0%-11.4%), respectively. Similar findings have been found in the GE system (n = 314). The CVs for the ADC_muscle measurements were lower than those of the ADC_spleen both in the repeatability and the comparability analyses (all p < 0.001).

Conclusion

Paraspinal muscles demonstrate better reference characteristics than the spleen in estimating ADC variability of abdominal DWI.

Does Bi-Exponential Fitting Perform Better than Mono-Exponential Fitting in IVIM-DWI? An Assessment of Renal Pathological Injury of IgA Nephropathy

BACKGROUND

Chronic kidney disease has become one of the world's major public health problems, immunoglobulin A (IgA) nephropathy is a common pathological type of CKD. Delaying the progression of IgA nephropathy has currently become the main clinical treatment strategy, precise evaluation of renal pathological injury during follow-up of patients with IgA nephropathy is important. Therefore, it is imperative to develop an accurate and non-invasive imaging technique for effective follow-up of renal pathological injury in patients with IgA nephropathy.

OBJECTIVE

To investigate the clinical value of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) in assessing renal pathological injury in patients with immunoglobulin A (IgA) nephropathy compared with a mono-exponential model.

METHODS

Altogether, 80 patients with IgA nephropathy were divided into the mild (41 cases) andmoderate-severe (m-s) renal injury groups (39 cases) according to pathology scores, and 20 healthy volunteers were recruited as controls. All participants underwent IVIM-DWI of the kidneys, and renal parenchymal apparent diffusion coefficient (ADC), pure molecular diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) values were measured. One-way analysis of variance, receiver operating characteristic (ROC) curve analysis, and Pearson correlation analysis were performed for all the DWI-derived parameters.

RESULTS

The DWI-derived parameters of the m-s renal injury group were significantly lower than those of the mild renal injury and control groups (P < 0.01). The ROC analysis revealed that f had the largest area under the ROC curve for differentiation between the m-s and mild renal injury groups and between the m-s renal injury and control groups. The f had the largest correlation coefficient with renal pathology scores (r=-0.81), followed by the D* (-0.69), ADC (-0.54), and D values (-0.53), respectively (all P<0.01).

CONCLUSION

IVIM-DWI demonstrated better diagnostic performance than the mono-exponential model in assessing renal pathological injury in patients with IgA nephropathy.

Measurements of the Elliptic and Triangular Azimuthal Anisotropies in Central ^{3}He+Au, d+Au and p+Au Collisions at sqrt[s_{NN}]=200 GeV

The elliptic (v_{2}) and triangular (v_{3}) azimuthal anisotropy coefficients in central ^{3}He+Au, d+Au, and p+Au collisions at sqrt[s_{NN}]=200  GeV are measured as a function of transverse momentum (p_{T}) at midrapidity (|η|<0.9), via the azimuthal angular correlation between two particles both at |η|<0.9. While the v_{2}(p_{T}) values depend on the colliding systems, the v_{3}(p_{T}) values are system independent within the uncertainties, suggesting an influence on eccentricity from subnucleonic fluctuations in these small-sized systems. These results also provide stringent constraints for the hydrodynamic modeling of these systems.

Saturation-prolongated and inhomogeneity-mitigated chemical exchange saturation transfer imaging with parallel transmission

Chemical exchange saturation transfer (CEST) imaging benefits from a longer saturation duration and a higher saturation duty cycle. Dielectric shading effects occur when the radiofrequency (RF) wavelength approaches the object size. Here, we proposed a simultaneous parallel transmission-based CEST (pTx-CEST) sequence to prolongate the saturation duration at a 100% duty cycle and improve the RF saturation homogeneity in CEST imaging. The simultaneous pTx-CEST sequence was implemented by switching the CEST saturation module from the non-pTx to pTx mode, using the pTx functionality with both transmit channels being driven simultaneously (instead of time-interleaved). The optimization of amplitude ratio and phase difference settings between RF channels for best B1 homogeneity was performed in phantoms of two different sizes mimicking the human brain and abdomen. The optimal amplitude and phase settings generating the best B1 homogeneity in the phantoms were used in pTx-CEST scans of the human study. The comparison of the maximum achievable saturation duration between the non-pTx-CEST and pTx-CEST sequences was performed in a protein phantom, healthy volunteers, and a metastatic brain tumor patient. The optimal amplitude ratio and phase difference setting between transmit channels manifested circular and elliptical polarization in the head-sized and abdomen-sized phantoms. In the brain, the maximum saturation durations achieved at a 100% duty cycle using the simultaneous pTx-CEST sequence were prolonged to 2240, 3220, and 4200 ms compared with 980 ms using the non-pTx-CEST sequence at repetition times of 3, 4, and 5 s, respectively. The longer saturation duration helped improve the image contrast between the tumor and the normal tissue in the patient. The optimized elliptical polarization mode saturation pulses yielded improved uniformity of CEST signals acquired from the human abdomen. The proposed simultaneous pTx-CEST sequence enabled essentially arbitrarily long saturation duration at a 100% duty cycle and helped reduce the dielectric shading effects with the optimized RF setting.

Observation of Directed Flow of Hypernuclei _{Λ}^{3}H and _{Λ}^{4}H in sqrt[s_{NN}]=3 GeV Au+Au Collisions at RHIC

We report here the first observation of directed flow (v_{1}) of the hypernuclei _{Λ}^{3}H and _{Λ}^{4}H in mid-central Au+Au collisions at sqrt[s_{NN}]=3  GeV at RHIC. These data are taken as part of the beam energy scan program carried out by the STAR experiment. From 165×10^{6} events in 5%-40% centrality, about 8400 _{Λ}^{3}H and 5200 _{Λ}^{4}H candidates are reconstructed through two- and three-body decay channels. We observe that these hypernuclei exhibit significant directed flow. Comparing to that of light nuclei, it is found that the midrapidity v_{1} slopes of _{Λ}^{3}H and _{Λ}^{4}H follow baryon number scaling, implying that the coalescence is the dominant mechanism for these hypernuclei production in the 3 GeV Au+Au collisions.

Beam Energy Dependence of Triton Production and Yield Ratio (N_{t}×N_{p}/N_{d}^{2}) in Au+Au Collisions at RHIC

We report the triton (t) production in midrapidity (|y|<0.5) Au+Au collisions at sqrt[s_{NN}]=7.7-200  GeV measured by the STAR experiment from the first phase of the beam energy scan at the Relativistic Heavy Ion Collider. The nuclear compound yield ratio (N_{t}×N_{p}/N_{d}^{2}), which is predicted to be sensitive to the fluctuation of local neutron density, is observed to decrease monotonically with increasing charged-particle multiplicity (dN_{ch}/dη) and follows a scaling behavior. The dN_{ch}/dη dependence of the yield ratio is compared to calculations from coalescence and thermal models. Enhancements in the yield ratios relative to the coalescence baseline are observed in the 0%-10% most central collisions at 19.6 and 27 GeV, with a significance of 2.3σ and 3.4σ, respectively, giving a combined significance of 4.1σ. The enhancements are not observed in peripheral collisions or model calculations without critical fluctuation, and decreases with a smaller p_{T} acceptance. The physics implications of these results on the QCD phase structure and the production mechanism of light nuclei in heavy-ion collisions are discussed.

A red ambient afterglow material with lifetime of 0.5 s and efficiency over 12

γCbPhAP, a D-A dyad with γ-carboline as the D unit and 3-phenylacenaphtho[1,2-b]pyrazine-8,9-dicarbonitrile as the A moiety and phosphorescence core, was designed and synthesized. The doping system of 1 wt% γCbPhAP in PMMA shows red ambient phosphorescence-dominated afterglow with long lifetime of 0.5 s and decent efficiency over 12%.

Distinguishing glutamate and glutamine in in vivo 1 H MRS based on nuclear spin singlet order filtering

PURPOSE

The signals of glutamate (Glu) and glutamine (Gln) are often significantly overlapped in routine ¹ H-MR spectra of human brain in vivo. Selectively probing the signals of Glu and Gln in vivo is very important for the study of the metabolisms in which Glu and Gln are involved.

METHODS

The Glu-/Gln- targeted pulse sequences are developed to selectively probe the signals of Glu and Gln. The core part of the Glu-/Gln- targeted pulse sequences lies on the preparation of the nuclear spin singlet orders (SSOs) of the five-spin systems of Glu and Gln. The optimal control method is used to prepare the SSOs of Glu and Gln with high efficiency.

RESULTS

The Glu-/Gln- targeted pulse sequences have been applied on phantoms to selectively probe the signals of Glu and Gln. Moreover, in the in vivo experiments, the signals of Glu and Gln in human brains of healthy subjects have been successfully probed separately.

CONCLUSION

The developed Glu-/Gln- targeted pulse sequences can be used to distinguish the ¹ H-MR signals of Glu and Gln in human brains in vivo. The optimal control method provides an effective way to prepare the SSO of a specific spin system with high efficiency and in turn selectively probe the signals of a targeted molecule.

Numerical fitting of Extrapolated semisolid Magnetization transfer Reference signals: Improved detection of ischemic stroke

PURPOSE

To propose a novel Numerical fitting method of the Extrapolated semisolid Magnetization transfer Reference (NEMR) signal for quantifying the CEST effect.

THEORY AND METHODS

Modified two-pool Bloch-McConnell equations were used to numerically fit the magnetization transfer (MT) and direct water saturation (DS) signals at far off-resonance frequencies, which was subsequently extrapolated into the frequency range of amide proton transfer (APT) and nuclear Overhauser enhancement (NOE) pools. Then the subtraction of the fitted two-pool z-spectrum and the experimentally acquired z-spectrum yielded APT^# and NOE^# signals mostly free of MT and DS contamination. Several strategies were used to accelerate the NEMR fitting. Furthermore, the proposed NEMR method was compared with the conventional extrapolated semisolid magnetization transfer reference (EMR) and magnetization transfer ratio asymmetry (MTR_asym ) methods in simulations and stroke patients.

RESULTS

The combination of RF downsampling, MT lineshape look-up table, and conversion of MATLAB code to C code accelerated the NEMR fitting by over 2700-fold. Monte-Carlo simulations showed that NEMR had higher accuracy than EMR and eliminated the requirement of the steady-state condition. In ischemic stroke patients, the NEMR maps at 1 μT removed hypointense artifacts seen on EMR and MTR_asym images, and better depicted stroke lesions than EMR. For NEMR, NOE^# yielded significantly (p < 0.05) stronger signal contrast between stroke and normal tissues than APT^# at 1 μT.

CONCLUSION

The proposed NEMR method is suitable for arbitrary saturation settings and can remove MT and DS contamination from the CEST signal for improved detection of ischemic stroke.

Transcriptomics Reveals the Effect of Strain Interactions on the Growth of A. Oryzae and Z. Rouxii

The microbial community structure in traditional fermented foods is quite complex, making the relationship between strains unclear. In this regard, the co-culture system can simulate microbial interactions during food fermentation and reveal the morphological changes, metabolic processes, and gene expression of microbial communities. The present study sought to investigate the effects of microbial interactions on the growth of Aspergillus oryzae and Zygosaccharomyces rouxii through omics. After co-cultivation, the pH value and dry weight were consistent with the pure culture of Z. rouxii. Additionally, the consumption of reducing sugar decreased, and the enzymatic activity increased compared with the pure culture of fungus. The analysis of volatile organic compounds (VOCs) and transcriptomics showed that co-culture significantly promoted the effect on Z. rouxii. A total of 6 different VOCs and 2202 differentially expressed genes were identified in the pure and co-culture of Z. rouxii. The differentially expressed genes were mainly related to the endonucleolytic cleavage of rRNA, ribosome biogenesis in eukaryotes, and RNA polymerase metabolic pathways. The study results will provide insights into the effect of microbial interactions on the growth of A. oryzae and Z. rouxii.

Measurement of Sequential ϒ Suppression in Au+Au Collisions at sqrt[s_{NN}]=200 GeV with the STAR Experiment

We report on measurements of sequential ϒ suppression in Au+Au collisions at sqrt[s_{NN}]=200  GeV with the STAR detector at the Relativistic Heavy Ion Collider (RHIC) through both the dielectron and dimuon decay channels. In the 0%-60% centrality class, the nuclear modification factors (R_{AA}), which quantify the level of yield suppression in heavy-ion collisions compared to p+p collisions, for ϒ(1S) and ϒ(2S) are 0.40±0.03(stat)±0.03(sys)±0.09(norm) and 0.26±0.08(stat)±0.02(sys)±0.06(norm), respectively, while the upper limit of the ϒ(3S) R_{AA} is 0.17 at a 95% confidence level. This provides experimental evidence that the ϒ(3S) is significantly more suppressed than the ϒ(1S) at RHIC. The level of suppression for ϒ(1S) is comparable to that observed at the much higher collision energy at the Large Hadron Collider. These results point to the creation of a medium at RHIC whose temperature is sufficiently high to strongly suppress excited ϒ states.

Beam Energy Dependence of Fifth- and Sixth-Order Net-Proton Number Fluctuations in Au+Au Collisions at RHIC

We report the beam energy and collision centrality dependence of fifth and sixth order cumulants (C_{5}, C_{6}) and factorial cumulants (κ_{5}, κ_{6}) of net-proton and proton number distributions, from center-of-mass energy (sqrt[s_{NN}]) 3 GeV to 200 GeV Au+Au collisions at RHIC. Cumulant ratios of net-proton (taken as proxy for net-baryon) distributions generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at 3 GeV. The measured values of C_{6}/C_{2} for 0%-40% centrality collisions show progressively negative trend with decreasing energy, while it is positive for the lowest energy studied. These observed negative signs are consistent with QCD calculations (for baryon chemical potential, μ_{B}≤110  MeV) which contains the crossover transition range. In addition, for energies above 7.7 GeV, the measured proton κ_{n}, within uncertainties, does not support the two-component (Poisson+binomial) shape of proton number distributions that would be expected from a first-order phase transition. Taken in combination, the hyperorder proton number fluctuations suggest that the structure of QCD matter at high baryon density, μ_{B}∼750  MeV at sqrt[s_{NN}]=3  GeV is starkly different from those at vanishing μ_{B}∼24  MeV at sqrt[s_{NN}]=200  GeV and higher collision energies.

Single and combined toxicity assessment of primary or UV-aged microplastics and adsorbed organic pollutants on microalga Chlorella pyrenoidosa

Microplastics (MPs), an emerging pollutant, have been increasingly raising concern due to the potential impacts on aquatic organisms. Moreover, the environmental aged MPs always exhibit different environmental behavior and interaction effect with organic pollutants from virgin MPs. In this work, the single and combined toxicity impact on Chlorella pyrenoidosa, a symbiont representative, has been investigated between MPs (e.g., polyamide microplastic (PA6), 75 μm) and organic pollutants (e.g., sulfamethoxazole (SMX) and dicamba (DCB)). Growth inhibition, chlorophyll accumulation, superoxide dismutase (SOD), malondialdehyde (MDA), and catalase (CAT) were investigated with the primary or UV-aged PA6. Above 0.5 g/L PA6 (primary or UV-aged) inhibited cell growth and chlorophyll accumulation after 96 h cultivation as compared with the control. Besides, the inhibition impacts have enhanced as the UV-aging time extending in the single PA6 systems. The algae growth inhibition rate after 96 h cultivation in both the system i.e., single (PA6: 6.9%) and combined (PA6-SMX: 14.2%, PA6-DCB: 14.9%) was slightly lower than that of exposing in organic pollutants alone (SMX: 23.9%, DCB: 25.0%), while the chl. b concentration in 60 days UV-aged PA6 combined with SMX (1.19 mg/L) or DCB (1.40 mg/L) systems were higher than in single SMX (1.04 mg/L) or DCB (1.33 mg/L) system. In addition, there were several differences of the cellular oxidative stress in the combined system of SMX and DCB. Specially, it was not noticeable of three enzymatic activities for SMX exposing in the presence of primary or UV-aged PA6. While SOD, CAT, and MDA activities was obviously increasing after exposing in PA6 and DCB combined system, indicating the significant synergistic effect on algae cells damage. This research verified the remarkable combined toxicity between UV-aged MPs and organic pollutants on microalgae.

Prediction of tumor budding in patients with rectal adenocarcinoma using b-value threshold map

OBJECTIVE

To investigate the feasibility of b-value threshold (b_Threshold) map in preoperative evaluation of tumor budding (TB) in patients with locally advanced rectal cancer (LARC).

METHODS

Patients with LARC were enrolled and underwent diffusion-weighted imaging (DWI). Contrast-to-noise ratio (CNR) between the lesions and normal tissues was assessed using DWI and b_Threshold maps. TB was counted and scored using hematoxylin and eosin staining. Reproducibility for the apparent diffusion coefficient (ADC), b_Threshold values, and region-of-interest (ROI) sizes were compared. Differences in ADC and b_Threshold values with low-intermediate and high TB grades and the correlations between mean ADC and b_Threshold values with TB categories were analyzed. Diagnostic performance of ADC and b_Threshold values was assessed using area under the curve (AUC) and decision curve analysis.

RESULTS

Fifty-one patients were evaluated. The CNR on b_Threshold maps was significantly higher than that on DW images (9.807 ± 4.811 vs 7.779 ± 3.508, p = 0.005). Reproducibility was excellent for the ADC (ICC 0.933; CV 8.807%), b_Threshold values (ICC 0.958; CV 7.399%), and ROI sizes (ICC 0.934; CV 8.425%). Significant negative correlations were observed between mean ADC values and TB grades and positive correlations were observed between mean b_Threshold values and TB grades (p < 0.05). b_Threshold maps showed better diagnostic performance than ADC maps (AUC, 0.914 vs 0.726; p = 0.048).

CONCLUSIONS

In LARC patients, b_Threshold values could distinguish different TB grades better than ADC values, and b_Threshold maps may be a preoperative, non-invasive approach to evaluate TB grades.

KEY POINTS

• Compared with diffusion-weighted images, b_Threshold maps improved visualization and detection of rectal tumors. • Agreement and diagnostic performance of b_Threshold values are superior to apparent diffusion coefficient in assessing tumor budding grades in patients with locally advanced rectal cancer. • b_Threshold maps could be used to evaluate tumor budding grades non-invasively before operation.

Automated deep-learning system in the assessment of MRI-visible prostate cancer: comparison of advanced zoomed diffusion-weighted imaging and conventional technique

BACKGROUND

Deep-learning-based computer-aided diagnosis (DL-CAD) systems using MRI for prostate cancer (PCa) detection have demonstrated good performance. Nevertheless, DL-CAD systems are vulnerable to high heterogeneities in DWI, which can interfere with DL-CAD assessments and impair performance. This study aims to compare PCa detection of DL-CAD between zoomed-field-of-view echo-planar DWI (z-DWI) and full-field-of-view DWI (f-DWI) and find the risk factors affecting DL-CAD diagnostic efficiency.

METHODS

This retrospective study enrolled 354 consecutive participants who underwent MRI including T2WI, f-DWI, and z-DWI because of clinically suspected PCa. A DL-CAD was used to compare the performance of f-DWI and z-DWI both on a patient level and lesion level. We used the area under the curve (AUC) of receiver operating characteristics analysis and alternative free-response receiver operating characteristics analysis to compare the performances of DL-CAD using f- DWI and z-DWI. The risk factors affecting the DL-CAD were analyzed using logistic regression analyses. P values less than 0.05 were considered statistically significant.

RESULTS

DL-CAD with z-DWI had a significantly better overall accuracy than that with f-DWI both on patient level and lesion level (AUC_patient: 0.89 vs. 0.86; AUC_lesion: 0.86 vs. 0.76; P < .001). The contrast-to-noise ratio (CNR) of lesions in DWI was an independent risk factor of false positives (odds ratio [OR] = 1.12; P < .001). Rectal susceptibility artifacts, lesion diameter, and apparent diffusion coefficients (ADC) were independent risk factors of both false positives (OR_{rectal susceptibility artifact} = 5.46; OR_diameter, = 1.12; OR_ADC = 0.998; all P < .001) and false negatives (OR_{rectal susceptibility artifact} = 3.31; OR_diameter = 0.82; OR_ADC = 1.007; all P ≤ .03) of DL-CAD.

CONCLUSIONS

Z-DWI has potential to improve the detection performance of a prostate MRI based DL-CAD.

TRIAL REGISTRATION

ChiCTR, NO. ChiCTR2100041834 . Registered 7 January 2021.

Performance and mechanisms for tetrabromobisphenol A efficient degradation in a novel homogeneous advanced treatment based on S2O42- activated by Fe3

Tetrabromobisphenol A (TBBPA), a representative brominated flame retardant (BFR), generally could be debrominated and degraded effectively in photolysis systems with the high energy consumption. In this study, the novel sulfate radical (SO₄^•-) generation resource of dithionite (S₂O₄^2-), activated by the common transition metal of Fe³⁺, has been applied for establishing an innovative homogeneous advance treatment system for BFR treatment in water. When coupling Fe³⁺ with S₂O₄^2-, TBBPA degradation efficiency could be remarkably improved from 38.7% to 93.8% with the debromination and mineralization efficiency of 83.9% and 18.5% in 60 min, respectively. The primary reactive species also have been identified as SO₃^•-, SO₄^•- and •OH responsible for TBBPA treatment and the contributions of SO₄^•- and •OH have been calculated as 43.8% and 28.4% for TBBPA degradation, respectively. In Fe³⁺/S₂O₄^2- system, TBBPA was effectively degraded in a wide initial pH range (3.0-9.0), whose activation energy was calculated as 32.01 kJ mol^-1. Due to the only operation of reagents dosing, the energy consumption and cost could be decreasing significantly without any light energy input and reaction conditions (e.g., pH and dissolved oxygen) adjustment compared with the general photolysis process. Moreover, some possible degradation approaches of TBBPA also have been proposed via GC-MS including debromination, hydroxylation, methylation, and mineralization in Fe³⁺/S₂O₄^2- system. And these probable degradation pathways also have been confirmed with the decreased Gibbs free energy (ΔG) based on density functional theory (DFT). This study has revealed that it was promising of Fe³⁺/S₂O₄^2- system for BFRs degradation and detoxification efficiently through the simple operation and mild condtions.

New insights into the degradation and detoxification of methylene blue using heterogeneous-Fenton catalyzed by sustainable siderite

The huge application of synthetic dyes caused a severe impact in the environment. In the present study, a physico-chemical strategy of heterogeneous-Fenton catalyzed by the natural ferrous ore has been established for toxic chemical degradation, of which the complex and high-expense repetitive pH adjustment procedures were escaping. And this natural heterogeneous catalyst also could be recycled and sustainable for toxic substances treatment involved in synergetic adsorption and oxidation. The siderite, served as an adsorbent and catalyst for the degradation of methylene blue (MB). Siderite exhibited a better adsorption capacity with a saturated adsorption capacity of ∼11.08 mg/g. Batch adsorption experiments have verified that adsorption rate and adsorption equilibrium followed pseudo-second-order rate model and Langmuir isotherm equation, respectively. The combination with H₂O₂, showed significant enhancement of MB degradation without any pH adjustment. The effect of siderite dosage, H₂O₂ dosage, MB concentration, initial pH, and reaction temperature on MB degradation was investigated, which also has indicated the excellent catalytic performance of siderite. About 99.71% of MB was degraded in 480 min with initial pH of 7.0, reaction temperature of 25 °C, siderite, and H₂O₂ dosage of 2.5 g/L and 122.38 mM, respectively. It was found that siderite could be reused and remained high degradation efficiency on MB after 5 times reutilization, which also could demonstrate the sustainable and effective process to degrade organic pollution. The generation of reactive species including ·OH and O2·- have been confirmed based on scavenger test and electron spin resonance (ESR) analysis, which was dominated by heterogeneous reaction. The possible degradation mechanisms of MB have been predicted based on spectrum scanning and GC-MS analysis. Moreover, acute toxicity assessment with marine photobacterium Vibrio fisheri was conducted to investigate the toxicity change in the adsorption/oxidation coupled process. This sustainable heterogeneous-Fenton technology has been verified as a promising and applicable process for toxic organic chemicals removal due to effective mineralization and detoxification assisted with the natural ore mineral through the simple operation and mild condtions.

Collision-System and Beam-Energy Dependence of Anisotropic Flow Fluctuations

Elliptic flow measurements from two-, four-, and six-particle correlations are used to investigate flow fluctuations in collisions of U+U at sqrt[s_{NN}]=193  GeV, Cu+Au at sqrt[s_{NN}]=200  GeV and Au+Au spanning the range sqrt[s_{NN}]=11.5-200  GeV. The measurements show a strong dependence of the flow fluctuations on collision centrality, a modest dependence on system size, and very little if any, dependence on particle species and beam energy. The results, when compared to similar LHC measurements, viscous hydrodynamic calculations, and trento model eccentricities, indicate that initial-state-driven fluctuations predominate the flow fluctuations generated in the collisions studied.

Evaluation of interstitial fibrosis in chronic kidney disease by multiparametric functional MRI and histopathologic analysis

OBJECTIVES

To investigate the diagnostic value of functional MRI to assess renal interstitial fibrosis in patients with chronic kidney disease (CKD).

METHODS

We prospectively recruited 80 CKD patients who underwent renal biopsies and 16 healthy volunteers to undergo multiparametric functional MRI examinations. The Oxford MEST-C classification was used to score the interstitial fibrosis. The diagnostic performance of functional MRI to discriminate interstitial fibrosis was evaluated by calculating the area under the receiver operating characteristic (ROC) curves.

RESULTS

IgA nephropathy (60%) accounted for the majority of pathologic type in the CKD patients. Apparent diffusion coefficient (ADC) from diffusion-weighted imaging (DWI) was correlated with interstitial fibrosis (rho = -0.73). Decreased renal blood flow (RBF) derived from arterial spin labeling (rho = -0.78) and decreased perfusion fraction (f) derived from DWI (rho = -0.70) were accompanied by increased interstitial fibrosis. The T1 value from T1 mapping correlated with interstitial fibrosis (rho = 0.67) (all p < 0.01). The areas under the ROC curve for the discrimination of ≤ 25% vs. > 25% and ≤ 50% vs. > 50% interstitial fibrosis were 0.87 (95% confidence interval, 0.78 to 0.94) and 0.93 (0.86 to 0.98) by ADC, 0.84 (0.74 to 0.91) and 0.94 (0.86 to 0.98) by f, 0.93 (0.85 to 0.98) and 0.90 (0.82 to 0.96) by RBF, and 0.91 (0.83 to 0.96) and 0.77 (0.66 to 0.85) by T1, respectively.

CONCLUSIONS

Functional MRI parameters were strongly correlated with the interstitial fibrosis of CKD. Therefore, it might a powerful tool to assess interstitial fibrosis of CKD noninvasively.

KEY POINTS

• In CKD patients, the renal cortical ADC value decreased and T1 value increased significantly compared with healthy volunteers. • Functional MRI revealed significantly decreased renal perfusion in CKD patients compared with healthy volunteers. • The renal cortical ADC, f, RBF, and T1 values were strongly correlated with the interstitial fibrosis of CKD.

Prediction of new cerebral ischemic lesion after carotid artery stenting: a high-resolution vessel wall MRI-based radiomics analysis

OBJECTIVES

Carotid artery stenting (CAS) is an established treatment for local stenosis. The most common complication is new ipsilateral ischemic lesions (NIILs). This study aimed to develop models considering lesion morphological and compositional features, and radiomics to predict NIILs.

MATERIALS AND METHODS

One hundred and forty-six patients who underwent brain MRI and high-resolution vessel wall MR imaging (hrVWI) before and after CAS were retrospectively recruited. Lumen and outer wall boundaries were segmented on hrVWI as well as atherosclerotic components. A traditional model was constructed with patient clinical information, and lesion morphological and compositional features. Least absolute shrinkage and selection operator algorithm was performed to determine key radiomics features for reconstructing a radiomics model. The model in predicting NIILs was trained and its performance was tested.

RESULTS

Sixty-one patients were NIIL-positive and eighty-five negative. Volume percentage of intraplaque hemorrhage (IPH) and patients' clinical presentation (symptomatic/asymptomatic) were risk factors of NIILs. The traditional model considering these two features achieved an area under the curve (AUC) of 0.778 and 0.777 in the training and test cohorts, respectively. Twenty-two key radiomics features were identified and the model based on these features achieved an AUC of 0.885 and 0.801 in the two cohorts. The AUCs of the combined model considering IPH volume percentage, clinical presentation, and radiomics features were 0.893 and 0.842 in the training and test cohort respectively.

CONCLUSIONS

Compared with traditional features (clinical and compositional features), the combination of traditional and radiomics features improved the power in predicting NIILs after CAS.

KEY POINTS

• Volume percentage of IPH and symptomatic events were independent risk factors of new ipsilateral ischemic lesions (NIILs). • Radiomics features derived from carotid artery high-resolution vessel wall imaging had great potential in predicting NIILs after CAS. • The combination model with radiomics and traditional features further improved the diagnostic performance than traditional features alone.

Radiomics based on readout-segmented echo-planar imaging (RS-EPI) diffusion-weighted imaging (DWI) for prognostic risk stratification of patients with rectal cancer: a two-centre, machine learning study using the framework of predictive, preventive, and personalized medicine

Background

Currently, the rate of recurrence or metastasis (ROM) remains high in rectal cancer (RC) patients treated with the standard regimen. The potential of diffusion-weighted imaging (DWI) in predicting ROM risk has been reported, but the efficacy is insufficient.

Aims

This study investigated the potential of a new sequence called readout-segmented echo-planar imaging (RS-EPI) DWI in predicting the ROM risk of patients with RC using machine learning methods to achieve the principle of predictive, preventive, and personalized medicine (PPPM) application in RC treatment.

Methods

A total of 195 RC patients from two centres who directly received total mesorectal excision were retrospectively enrolled in our study. Machine learning methods, including recursive feature elimination (RFE), the synthetic minority oversampling technique (SMOTE), and the support vector machine (SVM) classifier, were used to construct models based on clinical-pathological factors (clinical model), radiomic features from RS-EPI DWI (radiomics model), and their combination (merged model). The Harrell concordance index (C-index) and the area under the time-dependent receiver operating characteristic curve (AUC) were calculated to evaluate the predictive performance at 1 year, 3 years, and 5 years. Kaplan‒Meier analysis was performed to evaluate the ability to stratify patients according to the risk of ROM.

Findings

The merged model performed well in predicting tumour ROM in patients with RC at 1 year, 3 years, and 5 years in both cohorts (AUC = 0.887/0.813/0.794; 0.819/0.795/0.783) and was significantly superior to the clinical model (AUC = 0.87 [95% CI: 0.80-0.93] vs. 0.71 [95% CI: 0.59-0.81], p = 0.009; C-index = 0.83 [95% CI: 0.76-0.90] vs. 0.68 [95% CI: 0.56-0.79], p = 0.002). It also had a significant ability to differentiate patients with a high and low risk of ROM (HR = 12.189 [95% CI: 4.976-29.853], p < 0.001; HR = 6.427 [95% CI: 2.265-13.036], p = 0.002).

Conclusion

Our developed merged model based on RS-EPI DWI accurately predicted and effectively stratified patients with RC according to the ROM risk at an early stage with an individualized profile, which may be able to assist physicians in individualizing the treatment protocols and promote a meaningful paradigm shift in RC treatment from traditional reactive medicine to PPPM.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-022-00303-3.

Cyclic changes in T2* relaxometry of human uterus during the menstrual cycle using BOLD MR imaging

PURPOSE

To evaluate dynamic changes of T2* values within the endometrium, junctional zone and myometrium during the menstrual cycle using blood oxygen level-dependent (BOLD) magnetic resonance imaging.

METHOD

Volunteers underwent MRI scans on menstrual phase, ovulatory phase and luteal phase, including T2-weighted imaging and BOLD MR imaging. Multi-gradient-recalled echo (MGRE) sequence was used to obtain BOLD MR images. T2* values of different uterine layers, including endometrium, junctional zone and myometrium, on sagittal images were analyzed quantitatively.

RESULTS

Twenty-four subjects calculated T2* values successfully. The T2* values of each zonal structure during menstruation were significantly lower than those during ovulatory phase (P < 0.05) and luteal phase (P < 0.001). The T2* value of junctional zone was significantly lower than that of the myometrium over all three menstrual phases (P = 0.000, menstrual; P = 0.000, ovulatory; P = 0.001, luteal). The mean T2* value in endometrium during the ovulatory phase was the highest of the uterine zones over menstrual cycle. During menstrual phase, there was no statistical difference between endometrium and junctional zone (P > 0.05). Conversely, the comparison of the T2* values between endometrium and myometrium, junctional zone and myometrium both showed significant difference (P = 0.000). The mean T2* values within endometrium during ovulatory phase and luteal phase were significantly higher than those within junctional zone and myometrium (P < 0.05).

CONCLUSIONS

Cyclic changes of T2* values in each zonal structure of the uterus were revealed during the menstrual cycle by means of BOLD technique, which may be potentially beneficial in investigating dysmenorrhea, guiding assisted reproductive technologies and monitoring hypoxia in gynecological tumors.

Algae-containing raw water treatment and by-products control based on ClO2 preoxidation-assisted coagulation/precipitation process

Eutrophication has become a great concern in recent years with the algae blooms in source water resulting in a serious threat posing to the safety of drinking water. Chlorine dioxide (ClO₂) has been served as an alternative oxidant for preoxidation or disinfection during drinking water treatment process due to its high oxidation efficiency and low risk of organic by-products formation. However, the generation of inorganic by-products including chlorite (ClO₂^-) and chlorate (ClO₃^-) has become a potential problem when applied in drinking water treatment. In this study, ClO₂ preoxidation-assisted coagulation/precipitation process was applied to improve the raw water quality, especially algae, turbidity, chemical oxygen demand (COD_Mn), and UV₂₅₄, and explore the formation mechanisms of inorganic by-products. It was found that the polymeric aluminum chloride (PAC) and ClO₂ have shown the best raw water treatment performance with the optimal dosage of 10 mg/L and 0.8 mg/L, respectively. Moreover, the initial pH also has exhibited a notable influence on pollutants treatment and by-products generation. Due to the adverse influence of algae and natural organic matters (NOM) and the generation of by-products, it was significant to investigate their inhibition effect on the water quality and the production of ClO₂^- and ClO₃^- in the ClO₂ preoxidation-assisted coagulation/precipitation process. Moreover, it was applicable of this process to apply for the algae-containing raw water (calculated as Chl.a lower than 50 μg/L) treatment with the ClO₂ dosage of less than 0.8 mg/L to achieve optimum treatment performance and minimum by-products generation.