55 research outputs found

    Rare solid and cystic presentation of hemangiopericytoma/ solitary fibrous tumor: A case report

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    Hemangiopericytoma/Solitary Fibrous Tumor (HPC/SFT) is a rare fibroblastic sarcoma characterized by hyper-vasculature and STAT6 trans-nuclear localization. Cystic HPC/SFT is extremely rare. Due to the scarcity of cystic HPC/SFT cases, diagnostic and treatment guidelines are not well established. To our knowledge, we present the first case of cystic HPC/SFT observed in the liver. In addition, the patient had over 6 years of recurrent hypervascular solid HPC/SFT in the brain, bone, leptomeninges, liver and lung prior to developing a cystic HPC/SFT. Briefly, a 37-year-old Caucasian female with a history of HPC/SFT presented with several enlarging cystic hepatic lesions on surveillance MRI. The cystic/nonenhancing nature of these liver metastases were confirmed by contrast-enhanced ultrasound. Due to diagnostic uncertainty, two of these hepatic cysts were removed laparoscopically and pathology confirmed cystic HPC/SFT with a high MIB-1 index. Previously, in 2014, the patient was diagnosed with solid intracranial grade III pseudopapillary mesenchymal HPC/SFT in the posterior fossa and underwent subtotal resection followed by external beam radiation. In 2017, she had recurrent intracranial, vertebral, and intraspinal intradural extramedullary HPC/SFTs followed by surgery, proton therapy, and SRS radiotherapy. In 2019, after an uneventful pregnancy and birth, routine surveillance revealed metastases in the liver requiring an extended right hepatectomy. In 2020-2021 two solid hypervascular hepatic HPC/SFT were found and treated with microwave ablation. Shortly afterwards, several rapidly growing hepatic cystic HPC/SFT lesions developed. Of note, she has not taken any systemic therapy, indicating the cystic tumors are from metastases rather than cystic degradation as a sequela of therapy. Overall, this case highlights that cystic metastasis are a potential clinical manifestation of solid HPC/SFT. Moreover, cystic HPC/SFT can co-exist with the more typical primary solid hypervascular HPC/SFTs in the same patient. Lastly, in this case cystic HPC/SFT had a higher growth rate and propensity to metastasize as compared to the solid equivalent.Peer reviewe

    The Atacama Cosmology Telescope: Data Characterization and Map Making

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    We present a description of the data reduction and mapmaking pipeline used for the 2008 observing season of the Atacama Cosmology Telescope (ACT). The data presented here at 148 GHz represent 12% of the 90 TB collected by ACT from 2007 to 2010. In 2008 we observed for 136 days, producing a total of 1423 hours of data (11 TB for the 148 GHz band only), with a daily average of 10.5 hours of observation. From these, 1085 hours were devoted to a 850 deg^2 stripe (11.2 hours by 9.1 deg) centered on a declination of -52.7 deg, while 175 hours were devoted to a 280 deg^2 stripe (4.5 hours by 4.8 deg) centered at the celestial equator. We discuss sources of statistical and systematic noise, calibration, telescope pointing, and data selection. Out of 1260 survey hours and 1024 detectors per array, 816 hours and 593 effective detectors remain after data selection for this frequency band, yielding a 38% survey efficiency. The total sensitivity in 2008, determined from the noise level between 5 Hz and 20 Hz in the time-ordered data stream (TOD), is 32 micro-Kelvin sqrt{s} in CMB units. Atmospheric brightness fluctuations constitute the main contaminant in the data and dominate the detector noise covariance at low frequencies in the TOD. The maps were made by solving the least-squares problem using the Preconditioned Conjugate Gradient method, incorporating the details of the detector and noise correlations. Cross-correlation with WMAP sky maps, as well as analysis from simulations, reveal that our maps are unbiased at multipoles ell > 300. This paper accompanies the public release of the 148 GHz southern stripe maps from 2008. The techniques described here will be applied to future maps and data releases.Comment: 20 pages, 18 figures, 6 tables, an ACT Collaboration pape

    Planck 2015 results. V. LFI calibration

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    We present a description of the pipeline used to calibrate the Planck Low Frequency Instrument (LFI) timelines into thermodynamic temperatures for the Planck 2015 data release, covering four years of uninterrupted operations. As in the 2013 data release, our calibrator is provided by the spin-synchronous modulation of the cosmic microwave background dipole, but we now use the orbital component, rather than adopting the Wilkinson Microwave Anisotropy Probe (WMAP) solar dipole. This allows our 2015 LFI analysis to provide an independent Solar dipole estimate, which is in excellent agreement with that of HFI and within 1σ (0.3% in amplitude) of the WMAP value. This 0.3% shift in the peak-to-peak dipole temperature from WMAP and a general overhaul of the iterative calibration code increases the overall level of the LFI maps by 0.45% (30 GHz), 0.64% (44 GHz), and 0.82% (70 GHz) in temperature with respect to the 2013 Planck data release, thus reducing the discrepancy with the power spectrum measured by WMAP. We estimate that the LFI calibration uncertainty is now at the level of 0.20% for the 70 GHz map, 0.26% for the 44 GHz map, and 0.35% for the 30 GHz map. We provide a detailed description of the impact of all the changes implemented in the calibration since the previous data release

    Radiofrequency and microwave ablation in a porcine liver model: non-contrast CT and ultrasound radiologic-pathologic correlation

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    Purpose The goal of this study was to compare intra-procedural radiofrequency (RF) and microwave ablation appearance on non-contrast CT (NCCT) and ultrasound to the zone of pathologic necrosis. Materials and methods Twenty-one 5-min ablations were performed in vivo in swine liver with (1) microwave at 140 W, (2) microwave at 70 W, or (3) RF at 200 W (n = 7 each). CT and US images were obtained simultaneously at 1, 3, and 5 min during ablation and 2, 5, and 10 min post-ablation. Each ablation was sectioned in the plane of the ultrasound image and underwent vital staining to delineate cellular necrosis. CT was reformatted to the same plane as the ultrasound transducer and transverse diameters of gas and hypoechoic/hypoattenuating zones at each time point were measured. CT, ultrasound and gross pathologic diameter measurements were compared using Student’s t-tests and linear regression. Results Visible gas and the hypoechoic zone on US images were more predictive of the pathologic ablation zone than on NCCT images (p < 0.05). The zone of necrosis was larger than the zone of visible gas on US (mean 3.2 mm for microwave, 6.4 mm for RF) and NCCT (7.6 mm microwave, 13.9 mm RF) images (p < 0.05). The zone of visible gas and hypoechoic zone on US are more predictive of pathology with microwave ablations when compared with RF ablations (p < 0.05). Conclusion When evaluating images during energy delivery, US is more accurate than CT and microwave- more predictable than RF-ablation based on correlation with in-plane pathology
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