Deep Learning Accelerated Brain Diffusion-Weighted MRI with Super Resolution Processing.

OBJECTIVES: To investigate the clinical feasibility and image quality of accelerated brain diffusion-weighted imaging (DWI) with deep learning image reconstruction and super resolution. METHODS: 85 consecutive patients with clinically indicated MRI at a 3 T scanner were prospectively included. Conventional diffusion-weighted data (c-DWI) with four averages were obtained. Reconstructions of one and two averages, as well as deep learning diffusion-weighted imaging (DL-DWI), were accomplished. Three experienced readers evaluated the acquired data using a 5-point Likert scale regarding overall image quality, overall contrast, diagnostic confidence, occurrence of artefacts and evaluation of the central region, basal ganglia, brainstem, and cerebellum. To assess interrater agreement, Fleiss' kappa (Ï°) was determined. Signal intensity (SI) levels for basal ganglia and the central region were estimated via automated segmentation, and SI values of detected pathologies were measured. RESULTS: Intracranial pathologies were identified in 35 patients. DL-DWI was significantly superior for all defined parameters, independently from applied averages (p-value <0.001). Optimum image quality was achieved with DL-DWI by utilizing a single average (p-value <0.001), demonstrating very good (80.9%) to excellent image quality (14.5%) in nearly all cases, compared to 12.5% with very good and 0% with excellent image quality for c-MRI (p-value <0.001). Comparable results could be shown for diagnostic confidence. Inter-rater Fleiss' Kappa demonstrated moderate to substantial agreement for virtually all defined parameters, with good accordance, particularly for the assessment of pathologies (p = 0.74). Regarding SI values, no significant difference was found. CONCLUSION: Ultra-fast diffusion-weighted imaging with super resolution is feasible, resulting in highly accelerated brain imaging while increasing diagnostic image quality.

Ultrafast Brain MRI with Deep Learning Reconstruction for Suspected Acute Ischemic Stroke.

Background Deep learning (DL)-accelerated MRI can substantially reduce examination times. However, studies prospectively evaluating the diagnostic performance of DL-accelerated MRI reconstructions in acute suspected stroke are lacking. Purpose To investigate the interchangeability of DL-accelerated MRI with conventional MRI in patients with suspected acute ischemic stroke at 1.5 T. Materials and Methods In this prospective study, 211 participants with suspected acute stroke underwent clinically indicated MRI at 1.5 T between June 2022 and March 2023. For each participant, conventional MRI (including T1-weighted, T2-weighted, T2*-weighted, T2 fluid-attenuated inversion-recovery, and diffusion-weighted imaging; 14 minutes 18 seconds) and DL-accelerated MRI (same sequences; 3 minutes 4 seconds) were performed. The primary end point was the interchangeability between conventional and DL-accelerated MRI for acute ischemic infarction detection. Secondary end points were interchangeability regarding the affected vascular territory and clinically relevant secondary findings (eg, microbleeds, neoplasm). Three readers evaluated the overall occurrence of acute ischemic stroke, affected vascular territory, clinically relevant secondary findings, overall image quality, and diagnostic confidence. For acute ischemic lesions, size and signal intensities were assessed. The margin for interchangeability was chosen as 5%. For interrater agreement analysis and interrater reliability analysis, multirater Fleiss κ and the intraclass correlation coefficient, respectively, was determined. Results The study sample consisted of 211 participants (mean age, 65 years ± 16 [SD]); 123 male and 88 female). Acute ischemic stroke was confirmed in 79 participants. Interchangeability was demonstrated for all primary and secondary end points. No individual equivalence indexes (IEIs) exceeded the interchangeability margin of 5% (IEI, -0.002 [90% CI: -0.007, 0.004]). Almost perfect interrater agreement was observed (P > .91). DL-accelerated MRI provided higher overall image quality (P < .001) and diagnostic confidence (P < .001). The signal properties of acute ischemic infarctions were similar in both techniques and demonstrated good to excellent interrater reliability (intraclass correlation coefficient, ≥0.8). Conclusion Despite being four times faster, DL-accelerated brain MRI was interchangeable with conventional MRI for acute ischemic lesion detection. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Haller in this issue.

In Situ X-ray Diffraction Studies on the Reduction of V2 O5 and WO3 by Using Hydrogen.

The reduction of metal oxides with hydrogen is widely used for the production of fine chemicals and metals both on the laboratory and industry scale. In situ methods can help to elucidate reaction pathways and to gain control over such synthesis reactions. In this study, the reduction of WO3 and V2 O5 with hydrogen was investigated by in situ X-ray powder diffraction with regard to intermediates and the influence of heating rates and hydrogen flow rates. Mixtures of V4 O9 , V6 O13 and VO2 in two modifications were identified as intermediates on the way to phase-pure V2 O3 . None of the intermediates occurs in a single phase and therefore cannot be prepared this way. In contrast, the intermediates of the WO3 reduction, H0.23 WO3 and W10 O29 , appear consecutively and can be isolated. For both reactions, the heating and flow rates have little influence on the formation of intermediates.

Linking Electronic Health Records to the American Community Survey: Feasibility and Process.

Objectives. To assess linkages of patient data from a health care system in the southeastern United States to microdata from the American Community Survey (ACS) with the goal of better understanding health disparities and social determinants of health in the population. Methods. Once a data use agreement was in place, a stratified random sample of approximately 200 000 was drawn of patients aged 25 to 74 years with at least 2 visits between January 1, 2016, and December 31, 2019. Information from the sampled electronic health records (EHRs) was transferred securely to the Census Bureau, put through the Census Person Identification Validation System to assign Protected Identification Keys (PIKs) as unique identifiers wherever possible. EHRs with PIKs assigned were then linked to 2001-2017 ACS records with a PIK. Results. PIKs were assigned to 94% of the sampled patients. Of patients with PIKs, 15.5% matched to persons sampled in the ACS. Conclusions. Linking data from EHRs to ACS records is feasible and, with adjustments for differential coverage, will advance understanding of social determinants and enhance the ability of integrated delivery systems to reflect and affect the health of the populations served. (Am J Public Health. 2022;112(6):923-930. https://doi.org/10.2105/AJPH.2022.306783).

Cloning and heterologous expression of bovine pyroglutamyl peptidase type-1 in Escherichia coli: purification, biochemical and kinetic characterisation.

We describe the cloning, expression and purification of the bovine XM866409 form of pyroglutamyl peptidase type-1 (PAP1). The cloned nucleotide sequence has an ORF coding for a primary sequence of 209 amino acid residues, which displays 98% identity with the human AJ278828 form of the enzyme. Three amino acid residues at positions 81, 205 and 208 were found to vary between the two sequences. The recombinant bovine PAP1 with a C-terminal His(6) tag (rBtaPAP1(6H)) was expressed in Escherichia coli XL10-Gold cells and purified by immobilised nickel ion affinity chromatography resulting in a yield of 2.6 mg of PAP1 per litre of culture. Purified rBtaPAP1(6H) had a specific activity of 3633 units mg(-1). SDS-PAGE revealed a band for bovine PAP1 with a molecular weight of approximately 24 kDa, which is in good agreement with previously reported data on PAP1. The K (m) and k (cat) values obtained for rBtaPAP1(6H) were 59 muM and 3.5 s(-1), respectively. The optimum pH for activity was 9.0-9.5 and the optimum temperature was 37 degrees C. rBtaPAP1(6H) was found to have an absolute requirement for the thiol-reducing agent DTT, consistent with the expected property of a cysteine protease. Kinetic studies using the peptides pGlu-His-Pro-NH(2) (TRH), pGlu-Ala and pGlu-Val revealed K (i) values of 44.1, 141 and 652.17 microM, respectively. The lowest K (i), observed for Thyrotropin-releasing Hormone (TRH), indicates that rBtaPAP1(6H) has a higher affinity for tripeptides over dipeptides.