To assess the association between sex and clinical and disease activity indices, and X-rays and magnetic resonance imaging (MRI) features, in early-stage axial spondyloarthritis (axSpA).
Baseline ...data analysis was conducted on the Italian SPACE cohort, including patients with chronic back pain (duration ≥ 3 months and ≤ 2 years; onset < 45 years). Patients underwent MRI and X-rays of the sacroiliac joints (SIJs) to establish the diagnosis of axSpA, according to Assessment of SpondyloArthritis international Society criteria and physician's judgement. Clinical features, disease activity and functional indices, and images were collected at baseline and yearly during 48 months. Spinal and SIJ X-rays and MRI images were scored by two readers following Spondyloarthritis Research Consortium of Canada (SPARCC), modified Stoke Ankylosing Spondylitis Spinal Score, and modified New York criteria. Characteristics of axSpA patients according to sex (male/female) were compared over time using descriptive statistics.
Ninety-one patients had axSpA (83.5% non-radiographic; 16.5% radiographic); 47.3% were male. Males were younger, with shorter duration of axial symptoms, and more frequently had HLA-B27 positivity, radiographic sacroiliitis with a bilateral/symmetric pattern, and more signs of spondylitis. Females more frequently showed peripheral/entheseal involvement and the non-radiographic phenotype. Males showed increased pelvic/spinal radiographic progression and more often had active sacroiliitis on MRI. Although the frequency of inflammatory corner lesions did not differ between males and females, localization varied, with more cervical/thoracic MRI-spine lesions in females and more lumbar lesions in males. We observed a significant downward trend of SPARCC SIJ/spine scores in all patients, irrespective of sex. More fat lesions were observed on MRI-spine in females and on MRI-SIJ in males.
Sex was associated with distinct axSpA features: females showed low-grade radiographic sacroiliitis and spinal progression, and a higher prevalence of cervical and thoracic spine MRI signs.
Aim To evaluate the modifications of the apparent diffusion coefficient (ADC) in myelomatous lesions before and after induction treatment and the correlation with patient response to therapy ...according to International Myeloma Working Group (IMWG) criteria. Materials and methods A homogeneous group of 18 patients with a diagnosis of symptomatic multiple myeloma who underwent whole-body MRI with diffusion-weighted imaging (DWI-MRI) before and after bortezomib-based induction chemotherapy were evaluated prospectively. Quantitative analysis of ADC maps of myelomatous lesions was performed with the following pattern types: focal pattern, diffuse pattern (moderate and severe), and “salt and pepper” pattern. Lesions were evaluated by quantitative image analysis including measurement of the mean ADC in three measurements. Imaging results were compared to laboratory results as the clinical reference standard. Results A statistically significant increase in ADC values were found in the lesions of patients that responded to treatment. Interestingly, focal lesions showed a strongly significant increase in ADC values in responders, whereas no significant variation in ADC value in non-focal lesions (diffuse pattern and “salt and peppers” pattern) between responders and non-responders group was demonstrated. Conclusions DWI-MRI could provide additional quantitative information useful in monitoring early therapy response according to ADC changes of focal lesions.
Very High Energy (VHE) photons are a powerful probe of fundamental physics under extreme conditions. During the recent years, the observation of g-rays throws light on the high energy Universe thanks ...to the current and future satellite-borne detectors and ground-based telescopes. Ground-based gamma-ray astronomy is part of a new field of fundamental research of Astroparticle Physics and recently made spectacular discoveries, studying sources that, already known in several other energy bands (i.e. gamma-ray, X-ray, radio and/or optical frequencies), are expected to be VHE gamma-rays emitters. In this contribution I present some recent results obtained with the MAGIC telescope, the world's largest single-dish Imaging Atmospheric Cherenkov Telescope (IACT). In particular I will discuss the VHE photons originated in extragalactic gamma-rays emitters: Active Galactic Nuclei (AGN) and Gamma Ray Bursts (GRBs).
ABSTRACT We present coordinated multiwavelength observations of the bright, nearby BL Lacertae object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, ...VERITAS, and other collaborations and instruments, providing data from radio to very high energy (VHE) γ-ray bands. NuSTAR yielded previously unattainable sensitivity in the 3-79 keV range, revealing that the spectrum softens when the source is dimmer until the X-ray spectral shape saturates into a steep power law, with no evidence for an exponential cutoff or additional hard components up to ∼80 keV. For the first time, we observed both the synchrotron and the inverse-Compton peaks of the spectral energy distribution (SED) simultaneously shifted to frequencies below the typical quiescent state by an order of magnitude. The fractional variability as a function of photon energy shows a double-bump structure that relates to the two bumps of the broadband SED. In each bump, the variability increases with energy, which, in the framework of the synchrotron self-Compton model, implies that the electrons with higher energies are more variable. The measured multi band variability, the significant X-ray-to-VHE correlation down to some of the lowest fluxes ever observed in both bands, the lack of correlation between optical/UV and X-ray flux, the low degree of polarization and its significant (random) variations, the short estimated electron cooling time, and the significantly longer variability timescale observed in the NuSTAR light curves point toward in situ electron acceleration and suggest that there are multiple compact regions contributing to the broadband emission of Mrk 421 during low-activity states.
MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located in the Canary island of La Palma. Since autumn 2009 both telescopes have been working together in stereoscopic mode, ...providing a significant improvement with respect to the previous single-telescope observations. We use observations of the Crab Nebula taken at low zenith angles to assess the performance of the MAGIC stereo system. The trigger threshold of the MAGIC telescopes is 50−60GeV. Advanced stereo analysis techniques allow MAGIC to achieve a sensitivity as good as (0.76±0.03)% of the Crab Nebula flux in 50h of observations above 290GeV. The angular resolution at those energies is better than ∼0.07°. We also perform a detailed study of possible systematic effects which may influence the analysis of the data taken with the MAGIC telescopes.
The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar Radio Source (in ...short: radio quasar) 3C 279, at a distance of more than 5 billion light-years (a redshift of 0.536). No quasar has been observed previously in very-high-energy gamma radiation, and this is also the most distant object detected emitting gamma rays above 50 gigaelectron volts. Because high-energy gamma rays may be stopped by interacting with the diffuse background light in the universe, the observations by MAGIC imply a low amount for such light, consistent with that known from galaxy counts.
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