BACKGROUND: The extent of lung involvement visualized by high-resolution computed tomography (HRCT) is a predictor of decline in forced vital capacity (FVC) in scleroderma-interstitial lung disease. Our objective was to evaluate the performance of three different HRCT-defined staging systems in the Scleroderma Lung Study I (SLS I) over a 1-year period. METHODS: We assessed two visual semiquantitative scores: the maximum fibrosis score (MaxFib, the fibrosis score in the zone of maximal lung involvement) and visual assessment of total lung involvement (TLI) as proposed by Goh and Wells. In addition, we evaluated the computer-aided diagnosis and calculated the quantitative percentage with fibrosis (QLF) and TLI.

RATIONALE AND OBJECTIVES: Tumor volume change has potential as a biomarker for diagnosis, therapy planning, and treatment response. Precision was evaluated and compared among semiautomated lung tumor volume measurement algorithms from clinical thoracic computed tomography data sets. The results inform approaches and testing requirements for establishing conformance with the Quantitative Imaging Biomarker Alliance (QIBA) Computed Tomography Volumetry Profile.MATERIALS AND METHODS: Industry and academic groups participated in a challenge study. Intra-algorithm repeatability and inter-algorithm reproducibility were estimated. Relative magnitudes of various sources of variability were estimated using a linear mixed effects model. Segmentation boundaries were compared to provide a basis on which to optimize algorithm performance for developers.

PURPOSE: One of the hallmarks of cancer immunotherapy is the long duration of responses, evident with cytokines like interleukin-2 or a variety of cancer vaccines. However, there is limited information available on very long term outcomes of patients treated with anti-cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) antibodies. Tremelimumab is an anti-CTLA-4 antibody of immunoglobulin G2 (IgG2) isotype initially tested in patients with advanced melanoma over 12 years ago. METHODS: We reviewed the outcomes of patients with advanced melanoma enrolled in four phase 1 and 2 tremelimumab trials at two sites to determine response rates and long-term survival.

Portable chest radiography is a fundamental and frequently utilized examination in the critically ill patient population. The chest radiograph often represents a timely investigation of new or rapidly evolving clinical findings and an evaluation of proper positioning of support tubes and catheters. Thoughtful consideration of the use of this simple yet valuable resource is crucial as medical cost containment becomes even more mandatory. This review addresses the role of chest radiography in the intensive care unit on the basis of the existing literature and as formed by a consensus of an expert panel on thoracic imaging through the American College of Radiology. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

RATIONALE: Annual computed tomography (CT) is now widely recommended for lung cancer screening in the United States, although concerns remain regarding the potential harms, including those from overdiagnosis. OBJECTIVES: To examine the effect of airflow limitation on overdiagnosis by comparing lung cancer incidence, histology, and stage shift in a subgroup of the National Lung Screening Trial (NLST). METHODS: In an NLST subgroup (n = 18,714), screening participants were randomized to annual computed tomography (CT, n = 9,357) or chest radiograph (n = 9,357) screening and monitored for a mean of 6.1 years. After baseline prebronchodilator spirometry, to identify the presence of airflow limitation, 18,475 subjects (99%) were assigned as having chronic obstructive pulmonary disease (COPD) or no COPD. Lung cancer prevalence, incidence, histology, and stage shift were compared after stratification by COPD.

A 44-year-old man presented with a 3-day history of persistent upper-back pain, chest discomfort, and dyspnea. He denied any precipitating events such as trauma or vigorous activity before the presentation of symptoms. His exercise capacity had been excellent. He is a lifetime nonsmoker and never had significant lung problems apart from intermittent asthma for which he had several ED visits in the past. Chest CT scan performed during an asthma exacerbation 2 years earlier demonstrated two left-side lung blebs. He had no prior surgical procedures.

INTRODUCTION: To assess the feasibility, safety and local tumor control of cryoablation for treatment of pulmonary metastases. MATERIALS AND METHODS: This Health Insurance Portability and Accountability Act (HIPAA) compliant, IRB-approved, multicenter, prospective, single arm study included 40 patients with 60 lung metastases treated during 48 cryoablation sessions, with currently a minimum of 12 months of follow-up. Patients were enrolled according to the following key inclusion criteria: 1 to 5 metastases from extrapulmonary cancers, with a maximal diameter of 3.5 cm. Local tumor control, disease-specific and overall survival rates were estimated using the Kaplan-Meier method. Complications and changes in physical function and quality of life were also evaluated using Karnofsky performance scale, Eastern Cooperative Oncology Group performance status classification, and Short Form-12 health survey.

PURPOSE: To summarize data on computed tomographic (CT) radiation doses collected from consecutive CT examinations performed at 12 facilities that can contribute to the creation of reference levels. MATERIALS AND METHODS: The study was approved by the institutional review boards of the collaborating institutions and was compliant with HIPAA. Radiation dose metrics were prospectively and electronically collected from 199 656 consecutive CT examinations in 83 181 adults and 3871 consecutive CT examinations in 2609 children at the five University of California medical centers during 2013. The median volume CT dose index (CTDIvol), dose-length product (DLP), and effective dose, along with the interquartile range (IQR), were calculated separately for adults and children and stratified according to anatomic region. Distributions for DLP and effective dose are reported for single-phase examinations, multiphase examinations, and all examinations.

Patient portals have the potential to provide content that is specifically tailored to a patient's information needs based on diagnoses and other factors. In this work, we conducted a survey of 41 lung cancer patients at an outpatient lung cancer clinic at the medical center of the University of California Los Angeles, to gain insight into these perceived information needs and opinions on the design of a portal to fulfill them. We found that patients requested access to information related to diagnosis and imaging, with more than half of the patients reporting that they did not anticipate an increase in anxiety due to access to medical record information via a portal. We also found that patient educational background did not lead to a significant difference in desires for explanations of reports and definitions of terms.

PET/CT with the glucose analog (18)F-FDG has several potential applications for monitoring tumor response to therapy in patients with non-small cell lung cancer (NSCLC). A prerequisite for many of these applications is detailed knowledge of the repeatability of quantitative parameters derived from (18)F-FDG PET/CT studies. METHODS: The repeatability of the (18)F-FDG signal was evaluated in 2 prospective multicenter trials. Patients with advanced NSCLC (tumor stage III-IV) underwent two (18)F-FDG PET/CT studies while not receiving therapy. Tumor (18)F-FDG uptake was quantified by measurement of the maximum standardized uptake value within a lesion (SUVmax) and the average SUV within a small volume of interest around the site of maximum uptake (SUVpeak). Analysis was performed for the lesion in the chest with the highest (18)F-FDG uptake and a size of at least 2 cm (target lesion) as well as for up to 6 additional lesions per patient. Repeatability was assessed by Bland-Altman plots and calculation of 95% repeatability coefficients (RCs) of the log-transformed SUV differences.

Although there has been extensive research done on the biological response to doses of ionizing radiation relevant to radiodiagnostic procedures, very few studies have examined radiation schemes similar to those frequently utilized in CT exams. Instead of a single exposure, CT exams are often made up of a series of scans separated on the order of minutes. DNA damage dose-response kinetics after radiation doses and schemes similar to CT protocols were established in both cultured (ESW-WT3) and whole blood lymphocytes and compared to higher dose exposures. Both the kinetics and extent of H2AX phosphorylation were found to be dose dependent. Damage induction and detection showed a clear dose response, albeit different, at all time points and differences in the DNA repair kinetics of ESW-WT3 and whole blood lymphocytes were characterized. Moreover, using a modified split-dose in vitro experiment, we show that phosphorylation of H2AX is significantly reduced after exposure to CT doses fractionated over a few minutes compared to the same total dose delivered as a single exposure. Because the split-dose exposures investigated here are more similar to those experienced during a CT examination, it is essential to understand why and how these differences occur. This work provides compelling evidence supporting differential biological responses not only between high and low doses, but also between single and multiple exposures to low doses of ionizing radiation.

PURPOSE: The aim of this study is to evaluate the difference in radiation doses from adult Brain-Neck CT angiography (CTA) between two CT scanners. METHODS: We collected CT dose index data (CTDIvol, DLP) from adult Brain-Neck CTA performed with two CT scanners (Sensation 64 (S64) and Definition AS (AS), Siemens Healthcare) performed at two of our facilities from Jan 1st to Dec 31th, 2014. X-ray dose management software (Radmetrics, Bayer Healthcare) was used to mine these data. All exams were performed with Tube Current Modulation (Care Dose 4D), tube voltage of 120 kVp, quality reference mAs of 300, beam collimation of 64*0.6 mm. The rotation time was set to 0.5 sec for S64 and 1.0 sec for AS. We also scanned an anthropomorphic skull and chest phantom under routine Brain-Neck CTA protocol with the two scanners and extracted the tube current values from the raw projection data.

CT is increasingly being used to stage and quantify the extent of diffuse lung diseases both in clinical practice and in treatment trials. The role of CT in the assessment of patients entering treatment trials has greatly expanded as clinical researchers and pharmaceutical companies have focused their efforts on developing safe and effective drugs for interstitial lung diseases, particularly for idiopathic pulmonary fibrosis. These efforts have culminated in the simultaneous approval by the US Food and Drug Administration of two new drugs for the treatment of idiopathic pulmonary fibrosis. CT features are a key part of the inclusion criteria in many drug trials and CT is now being used to refine the type of patients enrolled. Interest in the potential use of serial CT as an effectiveness endpoint is increasing. For chronic progressive diseases, mortality may not be a feasible endpoint and many surrogate markers have been explored, ranging from pulmonary function decline to biomarkers. However, these surrogate markers are not entirely reliable and combinations of endpoints, including change in disease extent on CT, are being investigated. Methods to assess disease severity with CT range from simple visual estimates to sophisticated quantification by use of software. In this Position Paper, which cannot be regarded as a comprehensive set of guidelines in view of present knowledge, we examine the uses of serial CT in clinical practice and in drug trials and draw attention to uncertainties and challenges for future research.

PURPOSE: Texture features have been investigated as a biomarker of response and malignancy. Because these features reflect local differences in density, they may be influenced by acquisition and reconstruction parameters. The purpose of this study was to investigate the effects of radiation dose level and reconstruction method on features derived from lung lesions. METHODS: With IRB approval, 33 lung tumor cases were identified from clinically indicated thoracic CT scans in which the raw projection (sinogram) data were available. Based on a previously-published technique, noise was added to the raw data to simulate reduced-dose versions of each case at 25%, 10% and 3% of the original dose. Original and simulated reduced dose projection data were reconstructed with conventional and two iterative-reconstruction settings, yielding 12 combinations of dose/recon conditions. One lesion from each case was contoured. At the reference condition (full dose, conventional recon), 17 lesions were randomly selected for repeat contouring (repeatability). For each lesion at each dose/recon condition, 151 texture measures were calculated. A paired differences approach was employed to compare feature variation from repeat contours at the reference condition to the variation observed in other dose/recon conditions (reproducibility). The ratio of standard deviation of the reproducibility to repeatability was used as the variation measure for each feature.

In the United States, Lung Cancer is responsible for more cancer deaths than the next four cancers combined. In addition, the 5 year survival rate for lung cancer patients has not improved over the past 40 to 50 years. To combat this deadly disease, in 2002 the National Cancer Institute launched a very large Randomized Control Trial called the National Lung Screening Trial (NLST). This trial would randomize subjects who had substantial risk of lung cancer (due to age and smoking history) into either a Chest X-ray arm or a low dose CT arm. In November 2010, the National Cancer Institute announced that the NLST had demonstrated 20% fewer lung cancer deaths among those who were screened with low-dose CT than with chest X-ray. In December 2013, the US Preventive Services Task Force recommended the use of Lung Cancer Screening using low dose CT and a little over a year later (Feb. 2015), CMS announced that Medicare would also cover Lung Cancer Screening using low dose CT. Thus private and public insurers are required to provide Lung Cancer Screening programs using CT to the appropriate population(s). The purpose of this Symposium is to inform medical physicists and prepare them to support the implementation of Lung Screening programs. This Symposium will focus on the clinical aspects of lung cancer screening, requirements of a screening registry for systematically capturing and tracking screening patients and results (such as required Medicare data elements) as well as the role of the medical physicist in screening programs, including the development of low dose CT screening protocols.

AIM: To perform a systematic review and meta-analysis of the effectiveness and complications of BRTO for gastric varices. MATERIALS AND METHODS: A systematic review was performed to identify relevant articles. Inclusion criteria were applied to select studies with at least ten patients with acute bleeding or at-risk gastric varices treated with BRTO. Meta-analysis with random effects model was performed to calculate data for immediate technical success, clinical success, and complications.

PURPOSE: We are developing a research pipeline for generating CT image series that represent a wide variety of acquisition and reconstruction conditions. As part of this effort, we need stand-alone filtered backprojection (FBP) and iterative reconstruction methods that: (1) can operate on the raw CT data from clinical scans and (2) can be integrated into an acquisition/reconstruction pipeline for evaluating effects of acquisition and reconstruction settings on Quantitative Imaging metrics and CAD algorithms. METHODS: Two reconstruction methods were developed: (1) a weighted FBP method, and (2) an iterative method based on sequential minimization of a penalized least-squares objective function (i.e. iterative coordinate descent). Both methods were adapted from previously-published algorithms. Using information about the raw CT data format obtained through a research agreement with Siemens Healthcare, we extracted the sinogram from a low-dose lung screening case acquired on a Sensation 64 scanner as part of the National Lung Screening Trial. We reconstructed the raw data on the scanner with a B50 kernel and again with each of our standalone reconstruction methods. A relatively sharp kernel was used in our FBP method to match the appearance of the B50 kernel. The iterative method used a regularization parameter of 1 and a stopping criterion of 200 iterations. The reconstructed field of view was 29 cm for all methods.

PURPOSE: Quantitative Imaging and CAD tasks performed with CT (e.g. lung nodule detection, assessment of tumor size, etc.) may be sensitive to image acquisition and reconstruction parameters such as dose level, image thickness and reconstruction method (FBP, iterative, etc.). The purpose of this work was to develop a research pipeline for generating CT image series that represent a wide variety of acquisition and reconstruction conditions under which CAD and Quantitative Imaging performance would be evaluated. METHODS: With IRB approval, we have collected the raw CT data from hundreds of patients. These raw sinogram files serve as the input to the research pipeline. To simulate a wide range of dose levels, we developed software which adds noise to the sinogram. Multiple reduced-dose sinograms can be generated for a single patient, and those reduced-dose sinograms are then fed either to the scanner's reconstruction engine or to our in-house reconstruction engine; each has conventional filtered back projection (FBP) and iterative reconstruction methods. After generating image series across a range of dose levels and reconstruction methods, we can evaluate the performance of various quantitative imaging or CAD tools in tasks such as automated and semi-automated lesion segmentation, assessment of lesion size, and measurement of density or texture.

PURPOSE: While Lung Cancer Screening CT is being performed at low doses, the purpose of this study was to investigate the effects of further reducing dose on the performance of a CAD nodule-detection algorithm. METHODS: We selected 50 cases from our local database of National Lung Screening Trial (NLST) patients for which we had both the image series and the raw CT data from the original scans. All scans were acquired with fixed mAs (25 for standard-sized patients, 40 for large patients) on a 64-slice scanner (Sensation 64, Siemens Healthcare). All images were reconstructed with 1-mm slice thickness, B50 kernel. 10 of the cases had at least one nodule reported on the NLST reader forms. Based on a previously-published technique, we added noise to the raw data to simulate reduced-dose versions of each case at 50% and 25% of the original NLST dose (i.e. approximately 1.0 and 0.5 mGy CTDIvol). For each case at each dose level, the CAD detection algorithm was run and nodules greater than 4 mm in diameter were reported. These CAD results were compared to "truth", defined as the approximate nodule centroids from the NLST reports. Subject-level mean sensitivities and false-positive rates were calculated for each dose level.

Thymoma is the most common primary tumor of the anterior mediastinum and often recurs after initial surgical resection. In this case series, percutaneous cryoablation, a locally ablative technique, was used to treat 25 mediastinal and pleural recurrent thymoma lesions in five patients. Safety and short-term efficacy data were collected. In 23 percutaneous cryoablations (92%), there were no or minimal complications. One serious complication, myasthenia gravis flare, occurred. Over the duration of follow-up (median, 331 d), 18 of 20 ablated lesions (90%) showed no evidence of local recurrence. Percutaneous cryoablation shows promise as a safe and effective treatment modality for recurrent thymoma.

The Quantitative Imaging Biomarker Alliance (QIBA) is a multidisciplinary consortium sponsored by the RSNA to define processes that enable the implementation and advancement of quantitative imaging methods described in a QIBA profile document that outlines the process to reliably and accurately measure imaging features. A QIBA profile includes factors such as technical (product-specific) standards, user activities, and relationship to a clinically meaningful metric, such as with nodule measurement in the course of CT screening for lung cancer. In this report, the authors describe how the QIBA approach is being applied to the measurement of small pulmonary nodules such as those found during low-dose CT-based lung cancer screening. All sources of variance with imaging measurement were defined for this process. Through a process of experimentation, literature review, and assembly of expert opinion, the strongest evidence was used to define how to best implement each step in the imaging acquisition and evaluation process. This systematic approach to implementing a quantitative imaging biomarker with standardized specifications for image acquisition and postprocessing for a specific quantitative measurement of a pulmonary nodule results in consistent performance characteristics of the measurement (eg, bias and variance). Implementation of the QIBA small nodule profile may allow more efficient and effective clinical management of the diagnostic workup of individuals found to have suspicious pulmonary nodules in the course of lung cancer screening evaluation.

RATIONALE AND OBJECTIVES: The purpose of this study was to quantify the degree of imaging-histologic discordance in a cohort of patients undergoing computed tomography (CT)-guided lung biopsy for focal lung disease. MATERIALS AND METHODS: A retrospective review was performed of 186 patients who underwent percutaneous lung biopsy of a parenchymal lesion at our institution between January and December 2009. Diagnostic radiology reports of CT or positron emission tomography-CTs performed before biopsy were used to classify the lesion as malignant or benign by five readers. Pathology reports of the biopsied lesions were classified by three readers. Inter-reader agreement and imaging-histologic concordance were quantified using kappa statistics. Discordant benign cases were then revisited to determine downstream effects.

BACKGROUND AND PURPOSE: Glioblastoma is a common primary brain tumor with a poor but variable prognosis. Our aim was to investigate the feasibility of MR perfusion imaging by using arterial spin-labeling for determining the prognosis of patients with glioblastoma. MATERIALS AND METHODS: Pseudocontinuous arterial spin-labeling with 3D background-suppressed gradient and spin-echo was acquired before surgery on 53 patients subsequently diagnosed with glioblastoma. The calculated CBF color maps were visually evaluated by 3 independent readers blinded to patient history. Pathologic and survival data were correlated with CBF map findings. Arterial spin-labeling values in tumor tissue were also quantified by using manual fixed-size ROIs.

PURPOSE: The extensive use of computed tomography (CT) in diagnostic procedures is accompanied by a growing need for more accurate and patient-specific dosimetry techniques. Optically stimulated luminescent dosimeters (OSLDs) offer a potential solution for patient-specific CT point-based surface dosimetry by measuring air kerma. The purpose of this work was to characterize the OSLD nanoDot for CT dosimetry, quantifying necessary correction factors, and evaluating the uncertainty of these factors. METHODS: A characterization of the Landauer OSL nanoDot (Landauer, Inc., Greenwood, IL) was conducted using both measurements and theoretical approaches in a CT environment. The effects of signal depletion, signal fading, dose linearity, and angular dependence were characterized through direct measurement for CT energies (80-140 kV) and delivered doses ranging from ~5 to >1000 mGy. Energy dependence as a function of scan parameters was evaluated using two independent approaches: direct measurement and a theoretical approach based on Burlin cavity theory and Monte Carlo simulated spectra. This beam-quality dependence was evaluated for a range of CT scanning parameters.

This paper describes the information retrieval step in Casama (Contextualized Semantic Maps), a project that summarizes and contextualizes current research papers on driver mutations in non-small cell lung cancer. Casama's representation of lung cancer studies aims to capture elements that will assist an end-user in retrieving studies and, importantly, judging their strength. This paper focuses on two types of study metadata: study objective and study design. 430 abstracts on EGFR and ALK mutations in lung cancer were annotated manually. Casama's support vector machine (SVM) automatically classified the abstracts by study objective with as much as 129% higher F-scores compared to PubMed's built-in filters. A second SVM classified the abstracts by epidemiological study design, suggesting strength of evidence at a more granular level than in previous work. The classification results and the top features determined by the classifiers suggest that this scheme would be generalizable to other mutations in lung cancer, as well as studies on driver mutations in other cancer domains.

Abstract: Somatostatin receptor imaging with (68)Ga-DOTATATE PET/CT (DOTATATE) is increasingly used for managing patients with neuroendocrine tumors. The objective of this study was to determine referring physicians' perspectives on the impact of DOTATATE on the management of neuroendocrine tumors. METHODS: A set of 2 questionnaires (pre-PET and post-PET) was sent to the referring physicians of 100 consecutive patients with known or suspected neuroendocrine tumors, who were evaluated with DOTATATE. Questionnaires on 88 patients were returned (response rate, 88%). Referring physicians categorized the DOTATATE findings on the basis of the written PET reports as negative, positive, or equivocal for disease. The likelihood for metastatic disease was scored as low, moderate, or high. The intended management before and changes as a consequence of the PET study were indicated.

RATIONALE AND OBJECTIVES: Median survival of patients with idiopathic pulmonary fibrosis (IPF) is 2-5 years. Sensitive imaging metrics can play a role in detecting early changes in therapeutic development. The aim of the present study was to compare known computed tomography (CT) histogram kurtosis and a classifier-based quantitative score to assess baseline severity and change over time in patients with IPF. MATERIALS AND METHODS: A total of 57 patients with at least baseline and paired follow-up scans were selected from an imaging database of standardized CT scans obtained from patients with IPF. CT histogram measurement of kurtosis and quantitative lung fibrosis (QLF) and quantitative interstitial lung disease (QILD) scores from a classification algorithm were calculated. Spearman rank correlations were used to assess associations between baseline severity and changes for all CT-derived measures compared to forced vital capacity (FVC) and carbon monoxide diffusion capacity (DLCO) (percent predicted).