-
Radiology. Cardiothoracic Imaging Feb 2024Purpose To achieve ultra-high temporal resolution (approximately 20 msec) in free-breathing, real-time cardiac cine MRI using golden-angle radial sparse parallel (GRASP)...
Purpose To achieve ultra-high temporal resolution (approximately 20 msec) in free-breathing, real-time cardiac cine MRI using golden-angle radial sparse parallel (GRASP) reconstruction amplified with view sharing (VS) and k-space-weighted image contrast (KWIC) filtering. Materials and Methods Fourteen pediatric patients with congenital heart disease (mean age [SD], 9 years ± 2; 13 male) and 10 adult patients with arrhythmia (mean age, 62 years ± 8; nine male) who underwent both standard breath-hold cine and free-breathing real-time cine using GRASP were retrospectively identified. To achieve high temporal resolution, each time frame was reconstructed using six radial spokes, corresponding to acceleration factors ranging from 24 to 32. To compensate for loss in spatial resolution resulting from over-regularization in GRASP, VS and KWIC filtering were incorporated. The blur metric, visual image quality scores, and biventricular parameters were compared between clinical and real-time cine images. Results In pediatric patients, the incorporation of VS and KWIC into GRASP (ie, GRASP + VS + KWIC) produced significantly ( < .05) sharper x-y-t (blur metric: 0.36 ± 0.03, 0.41 ± 0.03, 0.48 ± 0.03, respectively) and x-y-f (blur metric: 0.28 ± 0.02, 0.31 ± 0.03, 0.37 ± 0.03, respectively) component images compared with GRASP + VS and conventional GRASP. Only the noise score differed significantly between GRASP + VS + KWIC and clinical cine; all visual scores were above the clinically acceptable (3.0) cutoff point. Biventricular volumetric parameters strongly correlated ( > 0.85) between clinical and real-time cine images reconstructed with GRASP + VS + KWIC and were in good agreement (relative error < 6% for all parameters). In adult patients, the visual scores of all categories were significantly lower ( < .05) for clinical cine compared with real-time cine with GRASP + VS + KWIC, except for noise ( = .08). Conclusion Incorporating VS and KWIC filtering into GRASP reconstruction enables ultra-high temporal resolution (approximately 20 msec) without significant loss in spatial resolution. Cine, View Sharing, k-Space-weighted Image Contrast Filtering, Radial k-Space, Pediatrics, Arrhythmia, GRASP, Compressed Sensing, Real-Time, Free-Breathing © RSNA, 2024.
Topics: Adult; Humans; Male; Child; Middle Aged; Magnetic Resonance Imaging, Cine; Retrospective Studies; Magnetic Resonance Imaging; Tachypnea; Hyperventilation; Arrhythmias, Cardiac
PubMed: 38358330
DOI: 10.1148/ryct.230107 -
Nucleic Acids Research Mar 2024Arginine/R methylation (R-met) of proteins is a widespread post-translational modification (PTM), deposited by a family of protein arginine/R methyl transferase enzymes...
Arginine/R methylation (R-met) of proteins is a widespread post-translational modification (PTM), deposited by a family of protein arginine/R methyl transferase enzymes (PRMT). Regulations by R-met are involved in key biological processes deeply studied in metazoan. Among those, post-transcriptional gene silencing (PTGS) can be regulated by R-met in animals and in plants. It mainly contributes to safeguard processes as protection of genome integrity in germlines through the regulation of piRNA pathway in metazoan, or response to bacterial infection through the control of AGO2 in plants. So far, only PRMT5 has been identified as the AGO/PIWI R-met writer in higher eukaryotes. We uncovered that AGO1, the main PTGS effector regulating plant development, contains unique R-met features among the AGO/PIWI superfamily, and outstanding in eukaryotes. Indeed, AGO1 contains both symmetric (sDMA) and asymmetric (aDMA) R-dimethylations and is dually targeted by PRMT5 and by another type I PRMT in Arabidopsis thaliana. We showed also that loss of sDMA didn't compromise AtAGO1 subcellular trafficking in planta. Interestingly, we underscored that AtPRMT5 specifically promotes the loading of phasiRNA in AtAGO1. All our observations bring to consider this dual regulation of AtAGO1 in plant development and response to environment, and pinpoint the complexity of AGO1 post-translational regulation.
Topics: Animals; Arabidopsis; Arabidopsis Proteins; Arginine; Argonaute Proteins; Eukaryota; Plants; RNA Interference; Protein-Arginine N-Methyltransferases
PubMed: 38321923
DOI: 10.1093/nar/gkae045 -
Radiology. Imaging Cancer Mar 2024Purpose To determine the pathologic features of nonmass enhancement (NME) directly adjacent to biopsy-proven malignant masses (index masses) at preoperative MRI and...
Purpose To determine the pathologic features of nonmass enhancement (NME) directly adjacent to biopsy-proven malignant masses (index masses) at preoperative MRI and determine imaging characteristics that are associated with a malignant pathologic condition. Materials and Methods This retrospective study involved the review of breast MRI and mammography examinations performed for evaluating disease extent in patients newly diagnosed with breast cancer from July 1, 2016, to September 30, 2019. Inclusion criteria were limited to patients with an index mass and the presence of NME extending directly from the mass margins. Wilcoxon rank sum test, Fisher exact test, and χ test were used to analyze cancer, patient, and imaging characteristics associated with the NME diagnosis. Results Fifty-eight patients (mean age, 58 years ± 12 [SD]; all women) were included. Malignant pathologic findings for mass-associated NME occurred in 64% (37 of 58) of patients, 43% (16 of 37) with ductal carcinoma in situ and 57% (21 of 37) with invasive carcinoma. NME was more likely to be malignant when associated with an index cancer that had a low Ki-67 index (<20%) ( = .04). The presence of calcifications at mammography correlating with mass-associated NME was not significantly associated with malignant pathologic conditions ( = .19). The span of suspicious enhancement measured at MRI overestimated the true span of disease at histologic evaluation ( < .001), while there was no evidence of a difference between span of calcifications at mammography and true span of disease at histologic evaluation ( = .27). Conclusion Mass-associated NME at preoperative MRI was malignant in most patients with newly diagnosed breast cancer. The span of suspicious enhancement measured at MRI overestimated the true span of disease found at histologic evaluation. Breast, Mammography © RSNA, 2024 See also the commentary by Newell in this issue.
Topics: Female; Humans; Middle Aged; Breast Neoplasms; Retrospective Studies; Breast; Mammography; Magnetic Resonance Imaging; Calcinosis
PubMed: 38305717
DOI: 10.1148/rycan.230060 -
Physical Biology Jan 2024Proteins populate a manifold in the high-dimensional sequence space whose geometrical structure guides their natural evolution. Leveraging recently-developed structure...
Proteins populate a manifold in the high-dimensional sequence space whose geometrical structure guides their natural evolution. Leveraging recently-developed structure prediction tools based on transformer models, we first examine the protein sequence landscape as defined by an effective energy that is a proxy of sequence foldability. This landscape shares characteristics with optimization challenges encountered in machine learning and constraint satisfaction problems. Our analysis reveals that natural proteins predominantly reside in wide, flat minima within this energy landscape. To investigate further, we employ statistical mechanics algorithms specifically designed to explore regions with high local entropy in relatively flat landscapes. Our findings indicate that these specialized algorithms can identify valleys with higher entropy compared to those found using traditional methods such as Monte Carlo Markov Chains. In a proof-of-concept case, we find that these highly entropic minima exhibit significant similarities to natural sequences, especially in critical key sites and local entropy. Additionally, evaluations through Molecular Dynamics suggests that the stability of these sequences closely resembles that of natural proteins. Our tool combines advancements in machine learning and statistical physics, providing new insights into the exploration of sequence landscapes where wide, flat minima coexist alongside a majority of narrower minima.
Topics: Protein Folding; Amino Acid Sequence; Proteins; Entropy; Molecular Dynamics Simulation; Algorithms; Protein Conformation; Thermodynamics
PubMed: 38237200
DOI: 10.1088/1478-3975/ad205c -
Skeletal Radiology Jul 2024To evaluate the distribution of intra- and extraarticular MRI findings in children and adolescents with clinically suspected intraarticular cause of hip pain in order to...
PURPOSE
To evaluate the distribution of intra- and extraarticular MRI findings in children and adolescents with clinically suspected intraarticular cause of hip pain in order to assess the need for additional intraarticular contrast administration.
MATERIAL AND METHODS
Database was searched over a period of 34 months retrospectively for consecutive hip MR arthrography in young patients (8-17 years) with suspected intraarticular cause of hip or groin pain. Exclusion criteria were prior hip surgery, follow-up examination due to known intraarticular pathology, incomplete examination, qualitatively non-diagnostic examinations, and missing informed consent. Reports of fellowship-trained MSK radiologists were searched for intraarticular versus extraarticular findings explaining hip or groin pain.
RESULTS
Seventy patients (68% female; median age: 14.5 years; range:10.8-16.9 years) were analyzed. No reason for pain was found in 30 (42.9%) hips, extraarticular reasons in 20 (28.6%) cases, intraarticular in 14 (20.0%), and both (intra- and extraarticular) in 6 (8.6%) hips. Most common extraarticular reasons were apophysitis (14.3%), other bony stress reactions (12.9%), intramuscular edema (7%), tendinitis (5.7%), and trochanteric bursitis (4.3%). Labral pathology was the most common intraarticular finding (overall:34.3%; partial tear:15.7%, complete tear:15.7%), most frequent at the anterosuperior position (81.8%). Cartilage defects (1.4%), intraarticular neoplasia (1.4%), and tear of the femoral head ligament (2.8%) were rarely found. Synovitis and loose bodies were not observed. Cam-(37.1%) and pincer-configurations (47.1%) were common while hip dysplasia was rare (5.7%).
CONCLUSION
MRI in children and adolescents with hip pain should be done primarily without intraarticular contrast administration since most cases show an extraarticular pain reason or no diagnosis detectable with MRI.
Topics: Humans; Adolescent; Female; Male; Child; Magnetic Resonance Imaging; Hip Joint; Arthralgia; Contrast Media; Reproducibility of Results; Arthrography; Sensitivity and Specificity; Retrospective Studies; Joint Diseases
PubMed: 38206356
DOI: 10.1007/s00256-023-04552-9 -
Heliyon Jan 2024Esophageal cancer (EC) is a common and devastating tumor of the upper digestive tract. Unfortunately, by the time any symptoms have manifested, the disease has often... (Review)
Review
Esophageal cancer (EC) is a common and devastating tumor of the upper digestive tract. Unfortunately, by the time any symptoms have manifested, the disease has often progressed to an advanced stage and is accompanied by macro- and micrometastases, including in the bones. The treatment of esophageal cancer with bone metastases remains clinically challenging, given the poor prognosis associated with this condition. Effective prognostic biomarkers can help medical staff choose the appropriate operation and treatment plan, that is for most beneficial for making patients. Current treatments for esophageal cancer with bone metastases include pain-relieving drugs, surgical therapy, radiotherapy (RT), chemotherapy (CT, including molecular-targeted drug therapy), endocrine therapy (ET), bisphosphonates (BPs) and interventional therapy. Of these robust measures, radiotherapy has emerged as a particularly promising therapy for bone metastases from esophageal cancer. Substantial progress has been made in radiation therapy techniques since the discovery of X-rays by Roentgen in 1895. In its palliative capacity, the key goals of radiotherapy are to relieve the patients' bone pain and debilitate effects, including relieving spinal cord compression, correcting the spinal deformity and restoring spinal stability. However, it is worth mentioning that RT for esophageal cancer has various side effects. Currently, the available studies focused exclusively on radiotherapy for ECBM are too small to draw any definitive conclusions, and each of these studies has significant limitations. In this review, in addition to the epidemiology described at the beginning, we will explore the current prognostic biomarkers and radiotherapy for esophageal cancer, with a particular focus on those with bone metastases.
PubMed: 38170113
DOI: 10.1016/j.heliyon.2023.e23510 -
Radiology. Artificial Intelligence Jan 2024
Topics: Diagnostic Imaging; Archives; Radiography; Scotland
PubMed: 38166329
DOI: 10.1148/ryai.230466 -
RoFo : Fortschritte Auf Dem Gebiete Der... Jul 2024
Application of liver-specific contrast agents for evaluation of focal liver lesions - Expert recommendations from the Gastrointestinal and Abdominal Imaging Workgroup of the German Roentgen Society.
Topics: Humans; Contrast Media; Liver Neoplasms; Germany; Image Enhancement; Magnetic Resonance Imaging; Tomography, X-Ray Computed; Radiology; Liver; Societies, Medical
PubMed: 38113896
DOI: 10.1055/a-2192-9921 -
European Radiology Experimental Dec 2023To analyze regional variations in T2 and T2* relaxation times in wrist joint cartilage and the triangular fibrocartilage complex (TFCC) at 3 and 7 T and to compare...
BACKGROUND
To analyze regional variations in T2 and T2* relaxation times in wrist joint cartilage and the triangular fibrocartilage complex (TFCC) at 3 and 7 T and to compare values between field strengths.
METHODS
Twenty-five healthy controls and 25 patients with chronic wrist pain were examined at 3 and 7 T on the same day using T2- and T2*-weighted sequences. Six different regions of interest (ROIs) were evaluated for cartilage and 3 ROIs were evaluated at the TFCC based on manual segmentation. Paired t-tests were used to compare T2 and T2* values between field strengths and between different ROIs. Spearman's rank correlation was calculated to assess correlations between T2 and T2* time values at 3 and 7 T.
RESULTS
T2 and T2* time values of the cartilage differed significantly between 3 and 7 T for all ROIs (p ≤ 0.045), with one exception: at the distal lunate, no significant differences in T2 values were observed between field strengths. T2* values differed significantly between 3 and 7 T for all ROIs of the TFCC (p ≤ 0.001). Spearman's rank correlation between 3 and 7 T ranged from 0.03 to 0.62 for T2 values and from 0.01 to 0.48 for T2* values. T2 and T2* values for cartilage varied across anatomic locations in healthy controls at both 3 and 7 T.
CONCLUSION
Quantitative results of T2 and T2* mapping at the wrist differ between field strengths, with poor correlation between 3 and 7 T. Local variations in cartilage T2 and T2* values are observed in healthy individuals.
RELEVANCE STATEMENT
T2 and T2* mapping are feasible for compositional imaging of the TFCC and the cartilage at the wrist at both 3 and 7 T, but the clinical interpretation remains challenging due to differences between field strengths and variations between anatomic locations.
KEY POINTS
•Field strength and anatomic locations influence T2 and T2* values at the wrist. •T2 and T2* values have a poor correlation between 3 and 7 T. •Local reference values are needed for each anatomic location for reliable interpretation.
Topics: Humans; Wrist; Wrist Joint; Magnetic Resonance Imaging; Cartilage
PubMed: 38093075
DOI: 10.1186/s41747-023-00394-1 -
Radiology. Artificial Intelligence Nov 2023
PubMed: 38074781
DOI: 10.1148/ryai.230304