NIST proposes new universal standard for CT calibration

Scientists at the National Institute of Standards and Technology have proposed a new universal standard for calibrating computed tomography devices that they claim may improve comparisons between scans from various devices. The newly released calibration approach was outlined in a research paper recently published in the academic journal PLOS One, the NIST said in a press release. “If the technical community could agree on a definition, then the vendors could create measurements that are interchangeable. Right now, calibration is not as thorough as it could be. Better comparisons among scanners might allow us to establish cutoff points for disease—such as emphysema getting a particular Hounsfield score or lower,” NIST physicist and paper author Zachary Levine said in a press release. To calibrate CT machines, radiologists use an object called a phantom, which has a known radiodensity. The Phantom is used to verify that the machine is giving the appropriate measurement in Hounsfield Units, or HUs. But CT scanner tubes generate beams of photons with different wavelengths, according to the report, and the beams’ overall effect on the phantom must be averaged, making it “challenging to define the calibration.” In addition, the beams can be adjusted for scanning more or less dense objects, requiring a variable spectrum of light that makes it more difficult to calibrate across voltages, NIST researchers report. NIST researchers filled several p...
Source: Mass Device - Category: Medical Devices Authors: Tags: Featured Imaging National Institute of Standards and Technology Source Type: news

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This report details the pathological and radiological findings in a rare case of massive subcutaneous emphysema. A 74-year-old male presented with sudden onset dyspnea and facial swelling following a fall. His symptoms were refractory to treatments for anaphylaxis, which was suspected clinically, and he quickly succumbed. Autopsy, including post mortem CT scan revealed the underlying etiology to be multiple rib fractures with rupture of the parietal pleura, bilateral pneumothoraxes and massive subcutaneous emphysema involving the face, torso and upper limbs. Multiple frothy air bubbles were observed throughout the mediasti...
Source: Forensic Science, Medicine, and Pathology - Category: Forensic Medicine Source Type: research
CONCLUSIONS: This clinical scenario evaluates institutional management in two trauma centres for PNI and associated carotid artery injury, and compares it to current guidelines. In comparison with guideline recommendations, CTA scanning and the so called "No zone" approach appears to have assumed a more prominent role in management of PNI. PMID: 31307866 [PubMed - as supplied by publisher]
Source: PubMed: Eur J Vasc Endovasc ... - Category: Surgery Authors: Tags: Eur J Vasc Endovasc Surg Source Type: research
Conclusions: CT-derived lobar volume and emphysema quantification using the LungSeg program is efficient and reliable in allowing lobar volume assessment. LungSeg has low inter-user variability and agrees better with plethysmography for COPD assessment in our study.Respiration
Source: Respiration - Category: Respiratory Medicine Source Type: research
Abstract BACKGROUND: Tobacco smoke exposure is associated with emphysema and pulmonary fibrosis, both of which are irreversible. We have developed a new objective computed tomography (CT) analysis tool that combines densitometry with machine learning to detect high attenuation changes in visually normal appearing lung (NormHA) that may precede these diseases. METHODS: We trained the classification tool by placing 34528 training points in chest CT scans from 297 COPDGene participants. The tool was then used to classify lung tissue in 9038 participants as normal, emphysema, fibrotic/interstitial, or NormHA. Ass...
Source: Chest - Category: Respiratory Medicine Authors: Tags: Chest Source Type: research
Authors: Wilmshurst P Abstract In this issue, Anderson and colleagues report follow-up of divers who were found to have a persistent (patent) foramen ovale (PFO) or, in eleven cases, an atrial septal defect (ASD). In most divers diagnosis followed an episode of decompression illness (DCI). The efficacy of closure of the PFO/ASD in preventing future DCI was compared with conservative diving. They reported that in the closure group the occurrence of confirmed DCI decreased significantly compared with pre-closure, but in the conservative group this reduction was not significant. It is believed there are three requ...
Source: Diving and Hyperbaric Medicine - Category: Sports Medicine Tags: Diving Hyperb Med Source Type: research
This study presents a two-step deep learning architecture that enables accurate normalization of reconstruction kernel effects on emphysema quantification in low-dose CT. Deep learning is used to convert a CT image of a sharp kernel to that of a standard kernel with restoration of truncation artifacts and smoothing-free pixel size normalization. We selected 353 scans reconstructed by both standard and sharp kernels from four different CT scanners from the United States National Lung Screening Trial program database. A truncation artifact correction model was constructed with a combination of histogram extrapolation and a d...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research
1328Objectives: Characterization of malignant risk within lung nodules remains an uncertain science with both computed tomography (CT) and fluorodeoxyglucose (FDG) positron emission tomography (PET). While schema exist for CT and PET alone for lung nodule risk stratification, few studies have modeled the predictive value of combining CT and PET data. Existing CT predictive models may not be applicable in this setting, as patients referred for PET imaging are at higher risk for cancer than an unselected population. Our objective was to assess the value of combining CT parameters with PET parameters toward quantifying risk o...
Source: Journal of Nuclear Medicine - Category: Nuclear Medicine Authors: Tags: Lung Cancer Posters Source Type: research
Recent advances in bronchoscopic lung volume reduction (BLVR) offer new therapeutic alternatives for patients with emphysema and hyperinflation. Endobronchial valves and coils are 2 potential BLVR techniques which have been shown to improve pulmonary function and the quality of life in patients with emphysema. Current patient selection for LVR procedures relies on 3 main inclusion criteria: low attenuation area (in %), also known as emphysema score, heterogeneity score, and fissure integrity score. Volumetric analysis in combination with densitometric analysis of the affected lung lobe or segment with quantitative CT to de...
Source: Respiration - Category: Respiratory Medicine Source Type: research
AbstractPleuropulmonary blastoma (PPB) is a rare, malignant tumor of the lung and is the most common primary pulmonary malignancy in children. Here, we report a case of a boy who was diagnosed with type I regressed PPB after being mislabeled with congenital pulmonary malformation. A 10-year-old boy presented to our hospital with a history of worsening dyspnea. Since birth, his clinical status and radiographic images were concerning for congenital lobar emphysema that was managed conservatively. A chest computed tomography (CT) scan confirmed the persistence of a large cystic lesion and a diagnostic and therapeutic cystecto...
Source: Indian Journal of Thoracic and Cardiovascular Surgery - Category: Cardiovascular & Thoracic Surgery Source Type: research
ConclusionPrompt diagnosis with thoracic drainage and a damage control treatment plan might lead to good prognosis for patients with this rare and potentially fatal condition.
Source: International Journal of Surgery Case Reports - Category: Surgery Source Type: research
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