Observation of gravitational waves from the coalescence of a 2.5–4.5 M ⊙ compact object and a neutron star

We report the observation of a coalescing compact binary with component masses 2.5–4.5 M ⊙ and 1.2–2.0 M ⊙ (all measurements quoted at the 90% credible level). The gravitational-wave signal GW230529_181500 was observed during the fourth observing run of the LIGO–Virgo–KAGRA detector network on 2023 May 29 by the LIGO Livingston observatory. The primary component of the source has a mass less than 5 M ⊙ at 99% credibility. We cannot definitively determine from gravitational-wave data alone whether either component of the source is a neutron star or a black hole. However, given existing estimates of the maximum neutron star mass, we find the most probable interpretation of the source to be the coalescence of a neutron star with a black hole that has a mass between the most massive neutron stars and the least massive black holes observed in the Galaxy. We provisionally estimate a merger rate density of 55−47+127Gpc−3yr−1 for compact binary coalescences with properties similar to the source of GW230529_181500; assuming that the source is a neutron star–black hole merger, GW230529_181500-like sources may make up the majority of neutron star–black hole coalescences. The discovery of this system implies an increase in the expected rate of neutron star–black hole mergers with electromagnetic counterparts and provides further evidence for compact objects existing within the purported lower mass gap

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Mild endometriosis of the uterosacral ligaments: a retrospective study of magnetic resonance imaging performance for diagnosis

Research question: What are the diagnostic performances of magnetic resonance imaging (MRI) scans when used to identify mild endometriosis of the uterosacral ligaments (USL)?Design: Monocentric retrospective study of patients who underwent a pelvic MRI followed by laparoscopy for determination of endometriosis between January 2016 and December 2020. Patients were included whether endometriosis of USL was suspected or not, but patients presenting large lesions that left no doubt as to their endometriotic nature on the MRI were excluded. Six criteria for the description of USL on MRI were studied to determine their diagnostic performances in predicting the presence of endometriosis on laparoscopy as follows: asymmetry, thickening, irregularity, straightness, the presence of a nodule or a hypersignal T1 spot.Results: Seventy-seven patients were included. Among the criteria, 'asymmetry' and 'thickening' had the highest sensitivities (0.69 [95% confidence interval 0.54-0.80] and 0.51 [0.40-0.63], respectively) but moderate specificities (0.52 [0.31-0.73] and 0.62 [0.50-0.72]). Conversely, 'irregularity', 'nodule', 'straightness' and 'hypersignal T1 spot' were associated with high specificities (0.81 [0.70-0.89], 0.96 [0.89-0.99], 0.95 [0.87-0.99] and 0.99 [0.93-1.00], respectively) but poor sensitivities (0.22 [0.14-0.33], 0.12 [0.06-0.21], 0.08 [0.03-0.16] and 0.08 [0.03-0.16], respectively). The presence of at least one criterion for the description of the USL was associated with good sensitivity (0.80 [0.66-0.89]) but poor specificity (0.35 [0.16-0.57]).Conclusions: The results suggest that the identification of minimal changes in the normal appearance of USL should not automatically lead to a conclusion of mild endometriosis at this location

Radiomics model to classify mammary masses using breast DCE-MRI compared to the BI-RADS classification performance

International audienceRecent advanced in radiomics analysis could help to identify breast cancer among benign mammary masses. The aim was to create a radiomics signature using breast DCE-MRI extracted features to classify tumors and to compare the performances with the BI-RADS classification. Material and methods From September 2017 to December 2019 images, exams and records from consecutive patients with mammary masses on breast DCE-MRI and available histology from one center were retrospectively reviewed (79 patients, 97 masses). Exclusion criterion was malignant uncertainty. The tumors were split in a train-set (70%) and a test-set (30%). From 14 kinetics maps, 89 radiomics features were extracted, for a total of 1246 features per tumor. Feature selection was made using Boruta algorithm, to train a random forest algorithm on the train-set. BI-RADS classification was recorded from two radiologists. Results Seventy-seven patients were analyzed with 94 tumors, (71 malignant, 23 benign). Over 1246 features, 17 were selected from eight kinetic maps. On the test-set, the model reaches an AUC = 0.94 95 CI [0.85–1.00] and a specificity of 33% 95 CI [10–70]. There were 43/94 (46%) lesions BI-RADS4 (4a = 12/94 (13%); 4b = 9/94 (10%); and 4c = 22/94 (23%)). The BI-RADS score reached an AUC = 0.84 95 CI [0.73–0.95] and a specificity of 17% 95 CI [3–56]. There was no significant difference between the ROC curves for the model or the BI-RADS score ( p = 0.19). Conclusion A radiomics signature from features extracted using breast DCE-MRI can reach an AUC of 0.94 on a test-set and could provide as good results as BI-RADS to classify mammary masses

Progression of adenomyosis magnetic resonance imaging features under ulipristal acetate for symptomatic fibroids

International audienceResearch question: What is the evolution of adenomyosis on magnetic resonance imaging (MRI) after a 3-month treatment course of daily 5 mg doses of ulipristal acetate (UPA) for symptomatic fibroids?Design: A monocentric prospective pilot study on patients who underwent a 3-month treatment course of UPA for symptomatic fibroids between January 2014 and December 2017. Patients underwent pelvic MRI shortly before (pre-MRI) and after treatment (post-MRI). The diagnosis of adenomyosis on MRI was defined by the observation of intramyometrial cysts and/or haemorrhagic foci within these cystic cavities and/or a thickening of the junctional zone >12 mm. The progression of adenomyosis was defined by the presence of at least one of the aforementioned criteria of adenomyosis on the pre-MRI and by at least one of the following on the post-MRI: (i) increased thickness of the junctional zone ≥20% and/or (ii) increased number of intramyometrial cysts. The appearance of adenomyosis was defined by the absence of the aforementioned criteria of adenomyosis on the pre-MRI and the presence of at least one of these criteria on the post-MRI.Results: Seventy-two patients were included. The MRI features of adenomyosis progressed for 12 of 15 patients (80.0%) for whom adenomyosis was identified on the pre-MRI. An appearance of adenomyosis was identified after treatment for 15 of 57 patients (26.3%) for whom adenomyosis was not identified on the pre-MRI.Conclusions: A 3-month treatment course of daily 5 mg doses of UPA could provoke a short-term progression or an emergence of typical adenomyosis intramyometrial cysts on MRI examinations

ClearPEM-Sonic: a multimodal PET-Ultrasound mammography system

International audienceThe ClearPEM-Sonic is a multimodal system dedicated to mammography, capable of providing co-registered metabolic, anatomical and structural information through combination of positron emission tomography with ultrasound elastographic imaging. The project is aimed to improve early stage detection of breast cancer through the high-resolution and high-sensitivity metabolic information provided by PEM, and the high-resolution anatomic information from US. Further improvements in the specificity of the system is provided by the ability to rule out non-cancerous findings from PEM, taking advantage of elastography imaging information. The ClearPEM-Sonic has been developed by the Crystal Clear Collaboration and is currently installed at Hopital Nord, Marseille, in the frame of CERIMED, the European Centre for Research in Medical Imaging. The detector is based on LYSO:Ce crystals, each of 2x2x20 mm3, grouped in 192 matrices of 8x4 crys- tals. BaSO4 is used as coating material and reflector. Read out is performed individually on both 2x2 mm2 faces of each crystal, using avalanche photodiodes (APDs). The detector performance has been thoroughly tested during the commissioning phase, confirming a spatial resolution of 1.5 mm, and a DOI precision of 2 mm. The co-registration software developed has proved to accurately superimpose images coming from the different modalities with a precision better than 2 mm. The clinical trial (phase 1) is being carried out on 20 patients with a known breast lesion who have been injected with FDG for a whole-body PET/CT as part of their diagnostic process. Results are compared to conventional imaging and MRI, with biopsy as a golden standard, to validate the use of ClearPEM-Sonic as a clinical imaging instrument for early detection of breast cancer