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Purpose: Assess the impact of 24/7/365 emergency trauma radiology (ETR) coverage on Emergency Department (ED) patient flow in an urban, quaternary-care teaching hospital. Methods: Patient ED visit and imaging information were extracted from the hospital patient care information system for 2008 to 2018. An interrupted time-series approach with a comparison group was used to study the impact of 24/7/365 ETR on average monthly ED length of stay (ED-LOS) and Emergency Physician to disposition time (EP-DISP). Linear regression models were fit with abrupt and permanent interrupts for 24/7/365 ETR, a coefficient for comparison series and a SARIMA error term; subgroup analyses were performed by patient arrival time, imaging type and chief complaint. Results: During the study period, there were 949,029 ED visits and 739,796 diagnostic tests. Following implementation of 24/7/365 coverage, we found a significant decrease in EP-DISP time for patients requiring only radiographs (-29 min;95%CI:-52,-6) and a significant increase in EP-DISP time for major trauma patients (46 min;95%CI:13,79). No significant change in patient throughput was observed during evening hours for any patient subgroup. For overnight patients, there was a reduction in EP-DISP for patients with symptoms consistent with stroke (-78 min;95%CI:-131,-24) and for high acuity patients who required imaging (-33 min;95%CI:-57,-10). Changes in ED-LOS followed a similar pattern. Conclusions: At our institution, 24/7/365 in-house ETR staff radiology coverage was associated with improved ED flow for patients requiring only radiographs and for overnight stroke and high acuity patients. Major trauma patients spent more time in the ED, perhaps reflecting the required multidisciplinary management.

Purpose Cavitary lung lesions often pose a diagnostic challenge, and tissue sampling can be required to obtain a confident diagnosis. Many authors contend that a computed tomography-guided percutaneous transthoracic lung biopsy (PTLB) of a cavitary lung lesion places a patient at higher risk for systemic air embolism (SAE) compared with biopsy of a noncavitary lesion. Materials and methods We reviewed the literature for studies of SAE complicating PTLB. We searched English-language articles indexed through PubMed, Embase, and Ovid Medline and included articles published up to March 31, 2020. Results We identified 10 case reports of SAE complicating PTLB, and 3 case-cohort studies comparing cavitary and noncavitary lesion biopsy. Among the case-cohort studies reviewed, 4 SAE occurred among 145 biopsies of cavitary lesions (2.7%), and 65 SAE occurred among 3050 biopsies of noncavitary lesions (2.1%). The pooled odds ratio of PTLB complicating SAE of cavitary lesions compared with noncavitary lesions was 1.29 (95% confidence interval: 0.47-3.60). No deaths following SAE after computed tomography-guided PTLB of cavitary lesions were reported in recent literature. Conclusions On the basis of available evidence, air embolism rates are similar for PTLB of cavitary and noncavitary lesions. Additional research and registry studies are necessary to better understand this topic.

Pulmonary MRI provides structural and quantitative functional images of the lungs without ionizing radiation, but it has had limited clinical use due to low signal intensity from the lung parenchyma. The lack of radiation makes pulmonary MRI an ideal modality for pediatric examinations, pregnant women, and patients requiring serial and longitudinal follow-up. Fortunately, recent MRI techniques, including ultrashort echo time and zero echo time, are expanding clinical opportunities for pulmonary MRI. With the use of multicoil parallel acquisitions and acceleration methods, these techniques make pulmonary MRI practical for evaluating lung parenchymal and pulmonary vascular diseases. The purpose of this Fleischner Society position paper is to familiarize radiologists and other interested clinicians with these advances in pulmonary MRI and to stratify the Society recommendations for the clinical use of pulmonary MRI into three categories: (a) suggested for current clinical use, (b) promising but requiring further validation or regulatory approval, and (c) appropriate for research investigations. This position paper also provides recommendations for vendors and infrastructure, identifies methods for hypothesis-driven research, and suggests opportunities for prospective, randomized multicenter trials to investigate and validate lung MRI methods.

Objective In lung cancer screening practice low-dose computed tomography, diameter, and volumetric measurement have been used in the management of screen-detected lung nodules. The aim of this study was to compare the performance of nodule malignancy risk prediction tools using diameter or volume and between computer-aided detection (CAD) and radiologist measurements. Methods Multivariable logistic regression models were prepared by using data from two multicenter lung cancer screening trials. For model development and validation, baseline low-dose computed tomography scans from the Pan-Canadian Early Detection of Lung Cancer Study and a subset of National Lung Screening Trial (NLST) scans with lung nodules 3 mm or more in mean diameter were analyzed by using the CIRRUS Lung Screening Workstation (Radboud University Medical Center, Nijmegen, the Netherlands). In the NLST sample, nodules with cancer had been matched on the basis of size to nodules without cancer. Results Both CAD-based mean diameter and volume models showed excellent discrimination and calibration, with similar areas under the receiver operating characteristic curves of 0.947. The two CAD models had predictive performance similar to that of the radiologist-based model. In the NLST validation data, the CAD mean diameter and volume models also demonstrated excellent discrimination: areas under the curve of 0.810 and 0.821, respectively. These performance statistics are similar to those of the Pan-Canadian Early Detection of Lung Cancer Study malignancy probability model with use of these data and radiologist-measured maximum diameter. Conclusion Either CAD-based nodule diameter or volume can be used to assist in predicting a nodule's malignancy risk.

This retrospective study reports the frequency and severity of coronary artery motion on dual-source high-pitch (DSHP), conventional pitch single-source (SS), and dual-source dual-energy (DE) CT pulmonary angiography (CTPA) studies. Two hundred eighty-eight consecutive patients underwent CTPA scans for suspected pulmonary embolism between September 1, 2013 and January 31, 2014. One hundred ninety-four at DSHP scans, 57 SS scans, and 37 DE scans were analyzed. Coronary arteries were separated into nine segments, and coronary artery motion was qualitatively scored using a scale from 1 to 4 (non-interpretable to diagnostic with no motion artifacts). Signal intensity, noise, and signal to noise ratio (SNR) of the aorta, main pulmonary artery, and paraspinal muscles were also assessed. DSHP CTPA images had significantly less coronary artery motion, with 30.1% of coronary segments being fully evaluable compared to 4.2% of SS segments and 7.9% of DE segments (p

Purpose Primary lung cancers associated with cystic airspaces are increasingly being recognized; however, there is a paucity of data on their natural history. We aimed to evaluate the prevalence, pathologic, and imaging characteristics of cystic lung cancer in a regional thoracic surgery center with a focus on the evolution of computed tomography morphology over time. Materials and methods Consecutive patients referred for potential surgical management of primary lung cancer between January 2016 and December 2018 were included. Clinical, imaging, and pathologic data were collected at the time of diagnosis and at the time of the oldest computed tomography showing the target lesion. Descriptive analysis was carried out. Results A total of 441 cancers in 431 patients (185 males, 246 females), median age 69.6 years (interquartile range: 62.6 to 75.3 y), were assessed. Overall, 41/441 (9.3%) primary lung cancers were cystic at the time of diagnosis. The remaining showed solid (67%), part-solid (22%), and ground-glass (2%) morphologies. Histopathology of the cystic lung cancers at diagnosis included 31/41 (76%) adenocarcinomas, 8/41 (20%) squamous cell carcinomas, 1/41 (2%) adenosquamous carcinoma, and 1/41 (2%) unspecified non-small cell lung carcinoma. Overall, 8/34 (24%) cystic cancers at the time of diagnosis developed from different morphologic subtype precursor lesions, while 8/34 (24%) cystic precursor lesions also transitioned into part-solid or solid cancers at the time of diagnosis. Conclusions This study demonstrates that cystic airspaces within lung cancers are not uncommon, and may be seen transiently as cancers evolve. Increased awareness of the spectrum of cystic lung cancer morphology is important to improve diagnostic accuracy and lung cancer management.

Introduction The 2011 IASLC classification system proposes guidelines for radiologists and pathologists to classify adenocarcinomas spectrum lesions as preinvasive, minimally invasive adenocarcinoma (MIA), or invasive adenocarcinoma (IA). IA portends the worst clinical prognosis, and the imaging distinction between MIA and IA is controversial. Materials and methods Subsolid pulmonary nodules resected by microcoil localization over a three-year period were retrospectively reviewed by three chest radiologists and a pulmonary pathologist. Nodules were classified radiologically based on preoperative computed tomography (CT), with the solid nodule component measured on mediastinal windows applied to high-frequency lung kernel reconstructions, and pathologically according to 2011 IASLC criteria. Radiology interobserver and radiological-pathological variability of nodule classification, and potential reasons for nodule classification discordance were assessed. Results Seventy-one subsolid nodules in 67 patients were included. The average size of invasive disease focus at histopathology was 5 mm (standard deviation 5 mm). Radiology interobserver agreement of nodule classification was good (Cohen’s Kappa = 0.604, 95 % CI: 0.447 to 0.761). Agreement between consensus radiological interpretation and pathological category was fair (Cohen’s Kappa = 0.236, 95 % CI: 0.054−0.421). Radiological and pathological nodule classification were concordant in 52 % (37 of 71) of nodules. The IASLC proposed CT solid component cut-off of 5 mm to distinguish MIA and IA yielded a sensitivity of 59 % and specificity of 80 %. Common reasons for nodule classification discordance included multiple solid components within a nodule on CT, scar and stromal collapse at pathology, and measurement variability. Conclusion Solid component(s) within persistent part-solid pulmonary nodules raise suspicion for invasive adenocarcinoma. Preoperative imaging classification is frequently discordant from final pathology, reflecting interpretive and technical challenges in radiological and pathological analysis.

Summary: Background: Current lung cancer screening guidelines use either mean diameter, volume, or density of the largest lung nodule on the previous CT scan or appearance of a new nodule to ascertain the timing of the next CT scan. We aimed to develop an accurate screening protocol by estimating the 3-year lung cancer risk after two screening CT scans using deep learning of radiologists' CT readings and other universally available clinical information. Methods: A deep learning algorithm (referred to as DeepLR) was developed using data from participants who had received at least two CT screening scans up to 2 years apart in the National Lung Screening Trial (NLST; training cohort). Double-blinded validation was done using data from participants in the Pan-Canadian Early Detection of Lung Cancer (PanCan) study (validation cohort). The primary analysis was to compare accuracy of DeepLR scores to predict lung cancer incidence at 1 year, 2 years, and 3 years with the Lung CT Screening Reporting & Data System (Lung-RADS) and volume doubling time, using time-dependent area under the receiver operating characteristic curve (AUC) analysis. Findings: The training cohort consisted of 25 097 participants from NLST and the validation cohort comprised 2294 individuals from PanCan. In the validation cohort, DeepLR showed good discrimination, with 1-year, 2-year, and 3-year time-dependent AUC values for cancer diagnosis of 0·968 (SD 0·013), 0·946 (0·013), and 0·899 (0·017), respectively. Among individuals deemed high risk by DeepLR, 94%, 85%, and 71% of incident and interval lung cancers diagnosed within 1 year, 2 years, and 3 years, respectively, after the second screening CT scan were identified. Furthermore, individuals with high DeepLR scores had a significantly higher risk of mortality (hazard ratio 16·07, 95% CI 10·15–25·44; p

Lung Cancer screening trials have demonstrated significant mortality reduction. Low-Dose Computed Tomography (LDCT) screening can frequently discover many small nodules in at risk participants. However classification of these, sub-cm nodules as cancerous or benign is a challenging task even for expert clinicians. In this work we use machine learning (ML) techniques to differentiate, cancerous (clinically confirmed) and benign nodules (>5 years of follow-up). Data for this study is drawn from a screening study (PanCan) from which we selected 613 distinct nodules (141 cancerous, and ~size matched 472 benign). We analyzed texture and shape features (~170) that are extracted from the nodule with and without perimeter transition pixels to control for perimeter effects. Features are also extracted from the ring of parenchyma surrounding the nodule to account for tumor effects on surrounding tissue. From the equivalent location in the opposite lung, parenchymal characteristics were extracted which we use to normalize the nodule texture features in an effort to reduce scanner bias. Our preliminary results for machine learning classification have shown model accuracies of up to ~80% (feature selection and classification algorithm dependent). Radiomic feature data can be combined with patient demographic variables such as age, sex, and smoking status to further improve our models, reaching ~84% classification accuracy. When normalized by the opposite lung, 58% of texture features showed improved classification ability. A single feature from the ring of parenchyma surrounding the nodule achieved 73.5% accuracy. Others have shown that nodule area/volume is a good classifier; for this data set it gave 68% accuracy. Data exploration to study classification accuracies among different subsets of patients reveals a number of interesting trends. We have noted for instance that in patients without emphysema, tumors can be classified with much higher accuracy (>90%) than in those who suffer from it. This and other results detailing classification among specific patient groupings may prove relevant in any potential future clinical implementation of these results. Citation Format: Rohan Abraham, Ian Janzen, Saeed Seyyedi, Sukhinder Khattra, John Mayo, Ren Yuan, Renelle Meyers, Stephen Lam, Calum MacAulay. Machine learning CADx process for classification of lung nodules below the Lung-RADS 4A threshold in LDCT scans [abstract]. In: Proceedings of the AACR Virtual Special Conference on Artificial Intelligence, Diagnosis, and Imaging; 2021 Jan 13-14. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(5_Suppl):Abstract nr PO-053.

Purpose To determine if there is a statistically significant difference in the computed tomography (CT)–guided trans-thoracic needle biopsy diagnostic rate, complication rate, and degree of pathologist confidence in diagnosis between core needle biopsy (CNB) and fine needle aspiration biopsy (FNAB). Methods A retrospective cohort design was used to compare the diagnostic biopsy rate, diagnostic confidence, and biopsy-related complications of pneumothorax, chest tube placement, pulmonary hemorrhage, hemoptysis, admission to hospital, and length of stay between 251 transthoracic needle biopsies obtained via CNB (126) or FNAB (125). Complication rates were assessed using imaging and clinical follow-up. Final diagnosis was confirmed via surgical pathology or clinical follow-up over a period of up to 10 years. Results CNB provided diagnostic samples in 91% and FNA in 80% of biopsies, which was statistically significant ( P < .05). The sensitivities for CNB and FNAB were 89% (85 of 95) and 95% (84 of 88), respectively. The specificity of CNB was 100% (21 of 21) and for FNAB was 81% (2 of 11) with 2 false positives in the FNAB group. The differences in complication rate was not statistically significant for pneumothorax (50% vs 46%; determined by routine postbiopsy CT), chest tube (2% vs 4%), hemoptysis (4% vs 6%), and pulmonary hemorrhage (38% vs 47%) between FNAB and CNB, respectively. Seven patients requiring chest tube were admitted to hospital, 2 in the FNAB cohort for an average of 2.5 days and 5 in the CNB cohort for an average of 4.6 days. Conclusions CNB provided more diagnostic samples with no statistical difference in complication rate.

Objective The study objective was to provide a 5-year update on our tertiary-level institutional experience with computed tomography–guided platinum microcoil lung surgery. Methods A retrospective cross-sectional study was conducted. All patients admitted to the Thoracic Service at Vancouver General Hospital to undergo computed tomography–guided microcoil lung surgery were included. Key primary outcome variables were successful nodule localization and severity of adverse events associated with placement. Secondary outcomes included nodule characteristics on preoperative computed tomography chest and nodule surgical pathology. Continuous variables were reported as mean (± standard deviation), and counts were reported as proportions n (%). Results A total of 97 lung nodules were resected in 92 patients. Mean age was 65.3 (±10.6) years, and 59 (61%) were female. All 97 nodules (100%) were successfully localized using video-assisted thoracic surgery wedge resection. There were 59 cases (60.8%) of placement-related events noted on computed tomography of the chest. All were minor and self-limited in nature and did not require treatment: pneumothorax 45 (46.4%), lung hematoma 18 (18.6%), dislodgement 4 (4.1%), and hemoptysis 2 (2.1%). Mean nodule diameter was 13.2 mm (±6.7). Density was nonsolid in 27 (27.8%) and semi-solid in 27 (27.8%). There was a single case of positive surgical margin, and 4 (4.1%) went on to completion lobectomy. Non–small lung cancer was identified in 66 nodules. Conclusions Computed tomography–guided platinum microcoil lung surgery is safe with a favorable clinical adverse event profile and is suitable for poor-risk patients. The method is efficient, yielding 100% diagnostic localization in our 5-year update. It eliminates the need for thoracotomy and palpation to localize worrisome subpleural tiny nodules. It is ideal for the management of changing nodules concerning for early lung cancer and diagnosis of small indeterminate lung nodules or metastases.

The purpose of this study is to determine the utility of preoperative CT-guided microcoil localization followed by fluoroscopy guided video-assisted thoracoscopic resection in the diagnosis and management of small peripheral pulmonary nodules in patients with extra-thoracic malignancies. This study is a retrospective analysis of prospectively collected data between August 2003 and September 2013. Fifty patients with extra-thoracic malignancies underwent preoperative localization of small indeterminate pulmonary nodules using CT-guided microcoil localization. Nodules were then resected by video-assisted thoracoscopic resection wedge excision and intraoperative fluoroscopy guidance. Univariate and multivariate logistic regression analysis were conducted. Fifty patients with a history of 14 different extra-thoracic cancers (57% female, mean age 62 years) had 55 nodules resected (mean size = 12 mm, depth from visceral pleura = 22 mm). Histology of resected nodules showed metastasis (25 of 50 patients), benign (10 of 50), and (15 of 50) early stage primary lung cancer. Smokers were found 6 times more likely to present with primary lung cancer than metastasis (P0.009). CT-guided microcoil localization procedure was successful in all patients with a mean time of 31(10) minutes and allowed successful wedge resection in all cases with no major complications. The mean operative time and fluoroscopy time were 27(12) minutes and 3(5) minutes, respectively. Microcoil-guided thoracoscopic wedge resection was effective in achieving early definitive diagnosis and changed management in 50% of patients with presumed metastasis with minimal morbidity.

Aims Left atrial appendage (LAA) device imaging after endovascular closure is important to assess for device thrombus, residual leak, positioning, surrounding structures, and pericardial effusion. Cardiac CT angiography (CCTA) is well suited to assess these non-invasively. Methods and results We report our consecutive series of non-valvular atrial fibrillation patients who underwent CCTA post-LAA closure with Amplatzer Cardiac Plug (ACP), Amulet (second generation ACP), or WATCHMAN devices. Patients underwent CCTA typically 1–6 months post-implantation. Prospective cardiac-gated CCTA was performed with Toshiba 320-detector or Siemens 2nd generation 128-slice dual-source scanners, and images interpreted with VitreaWorkstation™. GFR

Growing, small, peripheral, pulmonary nodules in patients at high risk for lung cancer lead to requests for video-assisted thoracoscopic (VATS) resection for pathologic diagnosis. The purpose of this randomized controlled trial was to determine if preoperative localization using percutaneously placed computed tomography (CT)-guided platinum microcoils decreases the need for thoracotomy or VATS anatomic resection (segmentectomy/lobectomy) for diagnosis.Patients with undiagnosed nodules of 15 mm or less were randomized to either no localization or preoperative microcoil localization. Coils were placed with the distal end deep to the nodule and the superficial end coiled on the visceral pleural surface with subsequent visualization by intraoperative fluoroscopy and VATS. Nodules were removed by VATS wedge excision using endostaplers. The primary outcome was a VATS wedge excision for pathologic diagnosis of the nodule without the need for either thoracotomy or VATS anatomic resection.Sixty patients were randomized and 56 underwent surgery between March 2010 and June 2012. Twenty-nine underwent microcoil localization and 27 did not. The baseline characteristics (age, sex, forced expiratory volume in the first second of expiration, nodule size/depth) were similar. The coil group had a higher rate of successful diagnosis with VATS wedge resection alone (27/29 vs 13/27; P .001), decreased operative time to nodule excision (37 ± 39 vs 100 ± 67 minutes; P .001), and reduced stapler firings (3.7 ± 2.0 vs 5.9 ± 31; P = .003) with no difference in total costs. Pathologic diagnoses included 14 benign nodules, 32 primary lung malignancies, and 10 metastases. There were no clinically significant complications related to the coil placement or wedge resection.Preoperative CT-guided microcoil localization decreases the need for thoracotomy or VATS anatomic resection for the diagnosis of small peripheral pulmonary nodules.

Increased use of CT Pulmonary angiography in suspected pulmonary embolism (PE) has driven research to minimize radiation dose while maintaining image quality and diagnostic accuracy. Following institutional review board approval, we performed a retrospective comparison study in patients with suspected PE. Patients were scanned using an ultra high pitch dual source technique (pitch = 2.6) using 120 kV (SVCTPA) (n = 54) or 100 kV (RV-CTPA) (n = 52). SV-CTPA images were reconstructed using filtered back projection (SV-wFBP) and RV-CTPA images were reconstructed using both FBP (RV-wFBP) and Iterative Reconstruction (RV-IR). Comparison of radiation dose, diagnostic ability, subjective image noise, quality, and sharpness, diagnostic agreement, signal to noise (SNR) and contrast to noise ratios (CNR) were performed. Mean effective dose was 2.56 ± 0.19 mSv for the RV protocol compared to 5.36 ± 0.60 mSv for the SV. The RV-CTPA protocol resulted in a mean DLP reduction of 52 % and mean CTDI reduction of 51 %. Pulmonary artery SNR and CNR were significantly higher on RV-IR images than SV-wFBP (p = 0.007, p = 0.003). Mean subjective image noise, quality and sharpness scores did not differ significantly between the SV-wFBP and RVIR images (p > 0.05). Subjective quality scores were significantly better for the RV-IR group compared to the RV-wFBP group (p < 0.001). Agreement between readers for presence or absence of pulmonary emboli on RV-IR images was almost perfect (κ = 0.891, p < 0.001). Iterative reconstruction complements ultra high pitch dual source CTPA examinations acquired using a reduced voltage resulting in higher mean pulmonary artery SNR and CNR when compared to both RV-wFBP and SV-CTPA.

Despite the positive outcome of the recent randomized trial of computed tomography (CT) screening for lung cancer, substantial implementation challenges remain, including the clear reporting of relative risk and suggested workup of screen-detected nodules. Based on current literature, we propose a 6-level Lung-Reporting and Data System (LU-RADS) that classifies screening CTs by the nodule with the highest malignancy risk. As the LU-RADS level increases, the risk of malignancy increases. The LU-RADS level is linked directly to suggested follow-up pathways. Compared with current narrative reporting, this structure should improve communication with patients and clinicians, and provide a data collection framework to facilitate screening program evaluation and radiologist training. In overview, category 1 includes CTs with no nodules and returns the subject to routine screening. Category 2 scans harbor minimal risk, including

Rationale and Objectives To measure the impact of 1-year interventional fellowship training on fluoroscopic time and contrast media utilization in uterine artery embolization (UAE). Materials and Methods Retrospective single institution analysis of 323 consecutive UAEs performed by 12 interventional fellows using a standardized protocol. Fluoroscopy time and contrast media volume were recorded for each patient and correlated with stage of fellowship training. Preprocedure uterine volume (using MRI or ultrasound) was used as a measure of procedural complexity. Regression analysis was conducted per trainee factoring in duration of training, procedure number, supervising radiologist, uterine volume, and outcome variables of fluoroscopy time and contrast media volume. Results Median number of patients treated per trainee was 27 (range, 16-43) with mean fluoroscopic time 24.5 minutes (range, 4-90 min) and mean contrast volume 190 mL (range, 50-320 mL). Increasing uterine volume had no significant effect ( P > .05) on fluoroscopic time but significantly increased ( P 001) contrast media volume. Significant training effect was identified with decrease in fluoroscopic time ( P 001) and decrease in contrast volume ( P = . 02) over training. Over the course of a 1-year fellowship, these summed to a decrease of 12 minutes in UAE fluoroscopy time and 17 mL less contrast. Conclusion A significant ( P 05) training effect that is clinically relevant was demonstrated over the course of a yearlong interventional radiology fellowship program in performance of a standardized protocol for UAE. This data supports fellowship training as a basis for UAE credentialing and privileging.

Recent pathology studies report that the lungs of cigarette smokers may demonstrate small localized subpleural foci of interstitial fibrosis associated with emphysema. Pathologically, this lesion has been termed smoking-related interstitial fibrosis, respiratory bronchiolitis-interstitial lung disease (ILD) with fibrosis, or airspace enlargement with fibrosis, but it is commonly misinterpreted on imaging and biopsy as a diffuse fibrosing interstitial pneumonia. The high-resolution computed tomography (HRCT) appearance of this process has not been defined.We describe HRCT imaging of seven patients with this lesion present histologically.HRCT features consisted of patchy areas of mild reticulation around predominantly subpleural upper/mid zone emphysematous changes in all cases, with variable patchy ground-glass change in six cases. Pathologically, there were distinctly circumscribed foci of dense, often hyalinized, interstitial fibrosis mixed with emphysema; variable numbers of smoker's macrophages were present in the airspaces. The fibrosis was confined to the subpleural regions. Three patients with follow-up information were clinically stable.These data suggest that a CT pattern of patchy areas of reticular changes about predominantly upper zone emphysematous spaces may be seen in smokers who do not have clinical evidence of a diffuse ILD. We propose that this lesion be called respiratory bronchiolitis with fibrosis (RBF) to avoid confusion with other forms of ILD. RBF probably accounts for some of the cases of ILD seen in large radiologic surveys of smokers. The pathology literature indicates that RBF either has no functional effects or at worst represents mild, usually nonprogressive disease, and hence separation from other, more serious, forms of ILD is important. Recognition of this lesion on imaging may obviate the need for lung biopsy.

Imaging is pivotal in chest disease diagnosis as the chest wall renders the heart and lungs inaccessible to physical examination and chest disease symptoms are very nonspecific (eg, cough, shortness of breath). Very early in the development of medical x-ray technology, it was recognized that the chest radiograph could provide essential diagnostic information (eg, pneumonia, lung masses, pneumothorax, cardiac failure). For this reason there was rapid uptake of chest radiography, and it continues to be highly relevant, over 100 years later. However, the chest radiograph has substantial limitations as it only provides a single, 2-dimensional view of the complex 3-dimensional structure of the chest. Even with the addition of the lateral view, detection of small lung nodules may substantially vary amongst expert radiologists. Thus, while lung masses greater than 30 mm in diameter are reliably identified, it has been shown that depending on location, lung nodules may be missed with a median diameter of 19 mm [1]. The strongest prognostic indicator of lung nodule malignant potential is size. Therefore, the detection of small lung cancers is strongly correlated with improved 5-year survival. In the hope of improving lung cancer survival, randomized clinical trials of screening chest radiography were performed in the 1970s. However, these trials failed to show a significant effect on lung cancer mortality [2]. Failure of these trials to impact mortality was believed by some to be secondary to poor imaging of small nodules using plain radiography. Poor imaging also limited our understanding of the link between

A B S T R AC T Background Major issues in the implementation of screening for lung cancer by means of lowdose computed tomography (CT) are the definition of a positive result and the management of lung nodules detected on the scans. We conducted a populationbased prospective study to determine factors predicting the probability that lung nodules detected on the first screening low-dose CT scans are malignant or will be found to be malignant on follow-up. Methods We analyzed data from two cohorts of participants undergoing low-dose CT screening. The development data set included participants in the Pan-Canadian Early Detection of Lung Cancer Study (PanCan). The validation data set included participants involved in chemoprevention trials at the British Columbia Cancer Agency (BCCA), sponsored by the U.S. National Cancer Institute. The final outcomes of all nodules of any size that were detected on baseline low-dose CT scans were tracked. Parsimonious and fuller multivariable logistic-regression models were prepared to estimate the probability of lung cancer. Results In the PanCan data set, 1871 persons had 7008 nodules, of which 102 were malignant, and in the BCCA data set, 1090 persons had 5021 nodules, of which 42 were malignant. Among persons with nodules, the rates of cancer in the two data sets were 5.5% and 3.7%, respectively. Predictors of cancer in the model included older age, female sex, family history of lung cancer, emphysema, larger nodule size, location of the nodule in the upper lobe, part-solid nodule type, lower nodule count, and spiculation. Our final parsimonious and full models showed excellent discrimination and calibration, with areas under the receiver-operating-characteristic curve of more than 0.90, even for nodules that were 10 mm or smaller in the validation set. Conclusions Predictive tools based on patient and nodule characteristics can be used to accurately estimate the probability that lung nodules detected on baseline screening low-dose CT scans are malignant. (Funded by the Terry Fox Research Institute and others; ClinicalTrials.gov number, NCT00751660.)

Introduction: To assess the accuracy of CT pixel analysis for fat attenuation in pulmonary hamartomas. Methods: Retrospective review identified 32 patients in three separate groups; pathologically proven hamartoma (n = 11), hamartoma diagnosed on imaging (n = 9) and a control group (n = 14) of pathology-proven non-hamartomatous smoothly marginated solitary pulmonary nodules. All lesions were assessed using: visual assessment for fat, pixel analysis of the inner 2/3rds and mean attenuation of the entire lesion, using an internal reference for fat. Fat percentages on CT and at histology were compared. Results: Visual assessment for macroscopic fat was the most reliable method for diagnosing pulmonary hamartoma. Combining percentage of fatattenuation pixels in the inner 2/3rds of the lesion improved specificity to 100%. Mean attenuation or pixel analysis in isolation were not helpful in lesional characterization. Conclusion: Combining percentage fat-attenuating pixels in the inner 2/3rds with visual assessment for macroscopic fat improves specificity for diagnosing pulmonary hamartomas.

OBJECTIVE. The objective of our study was to estimate the mortality benefit-to-risk ratio of pulmonary CT angiography (CTA) by setting (ambulatory [emergency department or outpatient] or inpatient), age, and sex. MATERIALS AND METHODS. A retrospective evaluation of 1424 consecutive pulmonary CTA examinations was performed and the following information was recorded: examination setting, patient age, patient sex, pulmonary CTA interpretation for pulmonary embolus (PE), and CT radiation exposure (dose-length product). We estimated mortality benefit of pulmonary CTA by multiplying the rate of positive pulmonary CTA examinations by published estimates of mortality of untreated PE in ambulatory and inpatient settings. We estimated the lifetime attributable risk of cancer mortality due to radiation from pulmonary CTA by calculating the estimated effective dose and using sex-specific polynomial equations derived from the Biological Effects of Ionizing Radiation VII report. We calculated benefit-to-risk ratios by ...

To compare quantitative and subjective image quality and radiation dose between standard computed tomographic (CT) pulmonary angiography (CTPA) and CTPA with a dual-energy technique with reduced iodine load.This prospective study was approved by the institutional review board and each participant provided informed consent. Ninety-four patients (59% male; mean age ± standard deviation, 62 years ± 15) were randomized to one of two protocols: standard CTPA (100-120 kVp) with standard contrast medium injection (n = 46) and dual-energy CTPA (image reconstruction at 50 keV) with the same injection volume as in the standard protocol but composed of contrast medium and saline in a 1:1 fashion, resulting in 50% reduction in iodine load (n = 48). Signal intensity and noise in three central and two segmental pulmonary arteries were measured; signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. A five-point scale was used to subjectively evaluate vascular enhancement and image noise. The proportion of diagnostic (score, ≥ 3) studies and the interreader agreement regarding the dichotomized diagnostic versus nondiagnostic scale were compared between the two groups.Compared with standard CTPA, dual-energy CTPA demonstrated higher signal intensity in all pulmonary arteries (all P.01), inferior noise only in segmental arteries (P.05), higher SNR and CNR (both P.05), and compatible effective dose (P.05). The five-point score was higher in the standard CTPA protocol (P.05). The interreader agreement regarding the dichotomized diagnostic versus nondiagnostic scale was similar (P.05) between the two groups.Dual-energy CTPA with image reconstruction at 50 keV allows a significant reduction in iodine load while improving intravascular signal intensity, maintaining SNR and with comparable radiation dose.

Objective: To evaluate the significance of oesophageal dilatation on high-resolution CT (HRCT) chest in patients with systemic sclerosis. Methods: We retrospectively retrieved the database of patients with systemic sclerosis seen at our hospital between January 2008 and January 2009. A total of 50 patients (46 women and four men) who had HRCT chest, pulmonary function testing and echocardiography within 1 month were included in the study. Peak pulmonary artery (PA) pressures and pulmonary function testing were charted. The HRCT chest was interpreted by a chest radiologist. Oesophageal dilatation was defined as a luminal coronal diameter of ≥9 mm in infra-aortic oesophagus. Extent of ground glass, reticulation and honeycombing was objectively scored. Results: Statistical analysis using independent t-test showed that diffusion capacity of carbon monoxide was significantly lower (P = 0.042) and peak PA pressures were significantly higher (P = 0.045) in patients with oesophageal dilatation (n = 29) as compared with those without oesophageal dilatation (n = 21). The two cohorts had no significant difference in their total lung capacity and HRCT determined extent of interstitial lung disease. Conclusion: Patients with oesophageal dilatation on HRCT chest had significantly lower diffusion capacity of carbon monoxide and higher peak PA pressures, which suggest that these patients tend to have more severe pulmonary vascular disease.

The purpose of this study was to compare the subjective image quality, image noise, and radiation dose of chest CT images reconstructed with a 30% blend of iterative reconstruction and 70% conventional filtered back projection (FBP) with those of images generated with 100% FBP.Clinically indicated chest CT examinations of 292 consecutively registered patients were prospectively alternately assigned to two scanners on which different reconstruction techniques were used: adaptive statistical iterative reconstruction (ASIR) blended with FBP and 100% FBP. Both acquisitions were performed with dose modulation (noise index, 25 for ASIR and 21 for FBP). Patient demographics and habitus were recorded. Two radiologists blinded to the reconstruction algorithm independently scored subjective image quality on a 3-point Likert scale and measured image noise and radiation dose.Compared with FBP images, ASIR images had significantly lower subjective image quality (p = 0.01), less image noise (p = 0.02), and less radiation dose (p0.0001). The CT dose index of the ASIR cohort (11.3 ± 51) was significantly lower than that of the 100% FBP cohort (15.4 ± 6.3) (p0.0001). Interobserver agreement on subjective image quality was excellent for both ASIR and FBP (Cronbach α, 0.92, p0.0001; Cronbach α, 0.85, p0.0001).In clinically indicated chest CT examinations, ASIR images had better image quality and less image noise at a lower radiation dose than images acquired with a conventional FBP reconstruction algorithm.

To describe and characterize the potential for malignancy of noncalcified lung nodules adjacent to fissures that are often found in current or former heavy smokers who undergo computed tomography (CT) for lung cancer screening.Institutional review board approval and informed consent were obtained. Baseline and follow-up thin-section multidetector CT scans obtained in 146 consecutive subjects at high risk for lung cancer (age range, 50-75 years;30 pack-year smoking history) were retrospectively reviewed. Noncalcified nodules (NCNs) were categorized according to location (parenchymal, perifissural), shape, septal connection, manually measured diameter, diameter change, and lung cancer outcome at 7(1/2) years.Retrospective review of images from 146 baseline and 311 follow-up CT examinations revealed 837 NCNs in 128 subjects. Of those 837 nodules, 234 (28%), in 98 subjects, were adjacent to a fissure and thus classified as perifissural nodules (PFNs). Multiple (range, 2-14) PFNs were seen in 47 subjects. Most PFNs were triangular (102/234, 44%) or oval (98/234, 42%), were located inferior to the carina (196/234, 84%), and had a septal connection (171/234, 73%). The mean maximal length was 3.2 mm (range, 1-13 mm). During 2-year follow-up in 71 subjects, seven of 159 PFNs increased in size on one scan but were then stable. The authors searched a lung cancer registry 7(1/2) years after study entry and found 10 lung cancers in 139 of 146 study subjects who underwent complete follow-up; none of these cancers had originated from a PFN.PFNs are frequently seen on screening CT scans obtained in high-risk subjects. Although PFNs may show increased size at follow-up CT, the authors in this study found none that had developed into lung cancer; this suggests that the malignancy potential of PFNs is low. (c) RSNA, 2010.

OBJECTIVE. The purpose of this article is to familiarize the radiologist with the technical aspects of transcatheter aortic valve replacement (TAVR). The wide range of MDCT imaging findings that are critical for planning and performing TAVR will be reviewed.CONCLUSION. TAVR is developing into an effective and reproducible therapy for aortic valve stenosis. We describe the important role of MDCT in planning and performing TAVR in a large transcatheter valve program.

Transcatheter aortic valve replacement (TAVR) required precise knowledge of the anatomic dimensions and physical characteristics of the aortic valve, annulus, and aortic root. Most groups currently use angiography, transthoracic echocardiography (TTE), or transesophageal echocardiography (TEE) to assess aortic annulus dimensions and anatomy. However, multislice computed tomography (MSCT) may allow more detailed 3-dimensional assessment of the aortic root. Twenty-six patients referred for TAVR underwent MSCT. Scans were also obtained for 18 patients after TAVR. All patients underwent pre- and postprocedural aortic root angiography, TTE, and TEE. Mean differences in measured aortic annular diameters were 1.1 mm (95% confidence interval 0.5, 1.8) for calibrated angiography and TTE, -0.9 mm (95% confidence interval -1.7, -0.1 mm) for TTE and TEE, -0.3 mm (95% confidence interval -1.1, 0.6 mm) for MSCT (sagittal) and TTE, and -1.2 mm (95% confidence interval -2.2, -0.2 mm) for MSCT (sagittal) and TEE. Coronal systolic measurements using MSCT, which corresponded to angiographic orientation, were 3.2 mm (1st and 3rd quartiles 2.6, 3.9) larger than sagittal systolic measurements, which were in the same anatomic plane as standard TTE and TEE views. There was no significant association between either shape of the aortic annulus or amount of aortic valve calcium and development of perivalvular aortic regurgitation. After TAVR, the prosthesis extended to or beyond the inferior border of the left main ostium in 9 of 18 patients (50%), and in 11 patients (61%), valvular calcium was

OBJECTIVE. The purpose of this article is to familiarize the radiologist with radiation dose in cardiac CT imaging and explain the current methods for dose reduction.CONCLUSION. Advances in CT technology have resulted in a significant increase in cardiac CT applications. It is imperative that the radiologist understand the resulting dose implication to the patient and actively engage in optimal protocol design to achieve adequate image quality with patient dose reduction in mind.

Computed tomography (CT) examinations are increasingly used for clinical diagnostic and research purposes, as they provide in vivo anatomic information similar to that provided by gross anatomy. In conjunction with physiologic maneuvers or contrast media, CT may also provide in vivo physiologic information. Using calibrated acquisition protocols, accurate noninvasive measurements of tissue density, air volume, blood volume, and capillary perfusion can be performed. Serial CT scans can provide longitudinal measurements indicative of disease progression or regression, allowing noninvasive assessment of treatment effects. However, the X-ray radiation associated with CT has been associated with a small but significant increased risk of malignancy, which may be fatal. Large studies have detected this small risk, which appears to be related to the cumulative radiation dose of all previous exposures in a linear fashion. It has been shown that the risk from a given radiation exposure is greater in young people and females compared with older males. The combination of these two risk-enhancing factors, found in pregnant females, provides the greatest risk. Radiation risk decreases with increasing age for both men and women, asymptotically approaching zero. Radiation risk can be calculated using dose metrics provided on current CT scanners as outlined in this article. Ethically, given that radiation is associated with measurable risk, clinically indicated and research CT examinations must provide an increase in knowledge that has substantial benefit to the subject. This benefit should be related to the potential of saving of life or to the prevention or mitigation of serious disease.

To compare the detection rate of pulmonary abnormalities between conventional high-resolution computed tomography (HRCT) and high-resolution multidetector computed tomography (MDCT) in lung transplant recipients and to correlate a composite computed tomography (CT) score with bronchiolitis obliterans syndrome (BOS) stage.Twenty-four lung transplant recipients (12 single/12 double lung transplants, 13 males/11 females, mean age: 53 y, range: 28 to 71) underwent contiguous 16-slice high-resolution MDCT of the lungs at maximal inspiration and maximal expiration. Eight reformatted image sets were reconstructed: (i) contiguous 1-mm slice MDCT image set in the transverse, sagittal, and coronal image planes at maximal inspiration; (ii) contiguous 1-mm slice MDCT image set in the transverse, sagittal, and coronal image planes at maximal expiration; (iii) conventional HRCT image set of 1-mm slices every 10 mm at maximal inspiration; and (iv) conventional expiratory HRCT of 1-mm slices at 3 selected levels at maximal expiration. Individual pulmonary abnormalities were added to give a composite CT score. Individual abnormalities and the composite CT score were correlated with BOS stage, as based on functional testing of airflow obstruction, for each of the 8 image sets.Transverse, sagittal, and coronal MDCT correlated significantly with BOS stage (R=0.46, 0.49, 0.52, respectively), whereas conventional HRCT did not. Multiple regression analysis demonstrated that transverse MDCT was the only independent predictor of BOS stage (R=0.33, P0.01). Interobserver agreement for composite CT scores for HRCT, transverse, sagittal, and coronal MDCT were R2=0.89, 0.87, 0.83 and 0.80, respectively. Interobserver agreement for individual abnormalities was better with MDCT than with conventional HRCT.In lung transplant recipients, high-resolution MDCT detects significantly more pulmonary abnormalities and has better interobserver agreement than conventional HRCT and is an independent predictor of BOS stage.

Background To evaluate the effect of radiation dose and scanner manufacturer on quantitative CT scan measurements of lung morphology in smokers. Methods Low-dose and high-dose, inspiratory, multislice CT scans were obtained in 50 subjects at intervals of approximately 6 months (mean [± SD] interval, 0.5 ± 0.2 years). In another 30 subjects, multislice CT scans were acquired first using a GE LightSpeed Ultra (General Electric Healthcare; Milwaukee, WI), followed a mean time of 1.2 ± 0.4 years later by using a Siemens Sensation 16 scanner (Siemens Medical Solutions; Erlangen, Germany). Custom software was used to measure lung volume, mass, mean density, and the extent of emphysema using threshold cutoffs of −950, −910, and −856 Hounsfield units (HU) and the lowest 15th and 5th percentile points. Results The change in radiograph dose significantly affected measurements of emphysema assessed using mean lung density, threshold, or percentile methods. There were also interactions between dose and total lung volume for all of the measurements except the −950-HU threshold and the lowest fifth percentile point. These two emphysema measurements suggest that there was more emphysema found in the CT scans obtained using a lower radiograph dose. Only the mean lung density and −856-HU threshold showed significant effects between CT scanner manufacturers and interactions between total lung volume and scanner. All other measures of lung structure were not different between the two CT scanners. Conclusion CT scan measurements of very low density lung structures are significantly affected by radiation dose but are less sensitive to the lung volume. Image acquisition parameters including radiation dose, scanner type, and the subject's breath size should be standardized to estimate emphysema severity in longitudinal studies.

Purpose The purpose of this pilot study was to evaluate the safety and efficacy of preoperative computed tomography (CT)-guided percutaneous microcoil lung nodule localization without pleural marking compared with the established technique with pleural marking. Materials and methods Sixty-three consecutive patients (66.7% female, mean age 61.6±11.4 y) with 64 lung nodules resected between October 2008 and January 2014 were retrospectively evaluated. Of the nodules, 29.7% (n=19) had microcoil deployment with pleural marking (control group) and 70.3% (n=45) had microcoil deployment without pleural marking (pilot group). Clinical, pathologic, and imaging characteristics, radiation dose, CT procedure and operating room time, and complete resection and complication rates were compared between the pilot and control groups. Results There was no significant difference in nodule size (P=0.552) or distance from the pleural surface (P=0.222) between the pilot and control groups. However, mean procedure duration (53.6±18.3 vs. 72.8±25.3 min, P=0.001) and total effective radiation dose (5.1±2.6 vs. 7.1±4.9 mSv, P=0.039) were significantly lower in the pilot group compared with the control group. CT procedure-related complications (P=0.483) [including pneumothoraces (P=0.769) and pulmonary hemorrhage (P=1.000)], operating room time (P=0.926), complete resection rates (P=0.520), intraoperative complications (P=0.549), and postoperative complications (P=1.000) were similar between the pilot and control groups. Conclusions Preoperative CT-guided lung nodule microcoil localization performed without visceral pleural marking appears to decrease the CT procedure time and radiation dose while maintaining equivalent complete resection rates and procedural and surgical complications, when compared with microcoil localization performed with pleural marking.

The purpose of this study was to compare diaphragmatic motion on dual-source high-pitch (DS-HP) and conventional single-source (SS) CT scans in trauma patients. Seventy-five consecutive trauma patients who presented to a level one trauma center over a 6-month period were scanned with a standardized whole body trauma CT protocol including both DS-HP chest (pitch = 2.1–2.5) and SS abdominal CT scans. Subjective analysis of diaphragmatic motion was performed by two readers using a four-point motion scale in seven regions of the diaphragm on coronal and axial slices. An overall confidence score to exclude a diaphragmatic tear was determined (1 to 10, 10: completely confident and 1: impossible to exclude). Wilcoxon rank sum tests were used for statistical analysis, and p

Since its first introduction by Hounsfield and Cormack in 1972, computed tomography (CT) has become one of the most important imaging modalities in diagnostic imaging, because of its strong impact on patient outcome. As a result, CT utilization has risen 10% per year during the last 15 years in the USA [1] and 142% between 1998 and 2008 in Switzerland [2]. In 2008, CT was responsible for 68% of the yearly Swiss medical radiation exposure while accounting for only 6% of the ionizing radiation examinations [2]. Current knowledge on the attributable risk of cancer induction by low level medical imaging radiation exposure (

Computed tomographic (CT) scanning may enable earlier diagnosis of chronic lung allograft dysfunction than forced expiratory volume in 1 second (FEV1). A study was undertaken to determine intra-observer and inter-observer agreement of composite and air trapping CT scores, to examine the association of FEV1 with the composite and air trapping CT score, and to relate the baseline composite CT score to changes in FEV1 and changes in the composite CT score over 1 year.Lung function and baseline CT scans following transplantation and at subsequent annual follow ups were analysed in 38 lung transplant recipients. Scans were randomly scored by two observers for bronchiectasis, mucus plugging, airway wall thickening, consolidation, mosaic pattern, and air trapping, and re-scored after 1 month. CT scores were expressed on a scale of 0-100 and correlated with FEV1 as a percentage of the post-transplant baseline value.The mean (SD) interval between baseline and follow up CT scans was 11.2 (4.7) months. Inter-observer and intra-observer agreement was good for both the composite and air trapping CT scores. There was a significant association between FEV1 and the composite CT score, with each unit of worsening in the baseline composite CT score predicting a 1.55% and 1.37% worsening in FEV1 over the following year (p0.0001) and a 1.25 and 1.12 unit worsening in the composite CT score (p0.0001) for observers 1 and 2, respectively.These findings indicate a potential role for a composite CT scoring system in the early detection of bronchiolitis obliterans.

Background— Mitral annuloplasty is the most common surgical procedure performed for ischemic mitral regurgitation (MR). Surgical mitral annuloplasty is limited by morbidity, mortality, and MR recurrence. We evaluated the safety and feasibility of a transvenous catheter-delivered implantable device to provide a percutaneous alternative to surgical mitral annuloplasty. Methods and Results— Five patients with chronic ischemic MR underwent percutaneous transvenous implantation of an annuloplasty device in the coronary sinus. Implantation was successful in 4 patients. Baseline MR in the entire group was grade 3.0±0.7 and was reduced to grade 1.6±1.1 at the last postimplantation visit when the device was intact or the last postprocedural visit in the patient in whom the device was not successfully implanted. Separation of the bridge section of the device occurred in 3 of 4 implanted devices and was detected at 28 to 81 days after implantation. There were no postprocedural device-related complications. Conclusions— Percutaneous implantation of a device intended to remodel the mitral annulus is feasible. Initial experience suggests a possible favorable effect on MR. Percutaneous transvenous mitral annuloplasty warrants further evaluation as a less invasive alternative to surgical annuloplasty.

Background: Thoracic computed tomography (CT) for lung cancer screening is sensitive for the detection of early peripheral lung cancer but is not sensitive for detecting central preinvasive and microinvasive cancer. Our hypothesis is that the use of a two-step strategy, using a sputum biomarker, may increase the detection rate of lung cancer by identifying individuals at highest risk. Methods: We completed a pilot study of 561 volunteer current or former smokers 50 years of age or older, with a smoking history of more than or equal to 30 pack years. All subjects received induced sputum examination and low-dose thoracic CT scan and were offered autofluorescence bronchoscopy. Results: CT detected 2408 pulmonary nodules, 80% of which were less than or equal to 4 mm in diameter. During 2-year follow-up, 95% of these nodules were stable or resolved, with only 4% showing growth at any time. A total of 28 cancers were detected in 22 subjects: 21 by CT scan and seven by autofluorescence bronchoscopy. Overall, 0.9% nodules were malignant, but growth on more than or equal to two CT scans increased the malignancy rate to 75%. The mean diameter of malignant nodules on detection was 12.8 mm (range, 3 to 36.4 mm). However, 18% of malignant nodules were less than or equal to 4 mm in diameter when first seen. Conclusions: Multi-detector row CT scanners found multiple small nodules in most subjects screened, but most were stable over the 2-year follow-up. Persistent interval growth increases the probability of malignancy from less than 1% to 75%. One quarter of detected cancers were CT occult and only seen with autofluorescence bronchoscopy. Prescreening using a sputum biomarker improved the detection rate of lung cancer from 3 to 5%.

BACKGROUND: Computed tomography (CT) scans are used extensively to investigate chest disease because of their cross-sectional perspective and superior contrast resolution compared with chest radiographs. These advantages lead to a more accurate imaging assessment of thoracic disease. The actual use and evaluation of the clinical impact of thoracic CT has not been assessed since scanners became widely available.OBJECTIVE: To identify patterns of utilization, waiting times and the impact of CT scan results on clinical diagnoses.DESIGN: A before and after survey of physicians who had ordered thoracic CT scans.SETTING: Vancouver General Hospital – a tertiary care teaching centre in Vancouver, British Columbia.SUBJECTS: Physicians who had ordered CT scans.INTERVENTION: Physicians completed a standard questionnaire before and after the CT scan result was available.MEASUREMENTS: Changes in the clinical diagnosis, estimates of the probabilities for the diagnosis both before and after the CT scan, and waiting times.RESULTS: Four hundred fifty-four thoracic CT cases had completed questionnaires, of whom 80% were outpatients. A change in diagnosis was made in 48% of cases (25% with a normal CT scan and 23% with CT scan findings that indicated a different diagnosis). The largest change in probability scores for the clinical diagnosis before and after the CT scan was 43.9% for normal scans, while it was 36.3% for a different diagnosis and 26.3% for the same diagnosis. High-priority scans were associated with decreased waiting time (−7.89 days for each unit increase in priority).CONCLUSIONS: The CT scan results were associated with a change in diagnosis in 48% of cases. Normal scans constituted 25% of the total and had the greatest impact scores. Waiting times were highly correlated with increased urgency of the presenting problem.

L ung cancer is the most common cause of cancer death for both men and women in the industrialized world. Small-cell lung cancer accounts for about 25% of lung cancers and is usually widespread by the time it is first seen. The remaining 75%of lung cancers are collectively termed non–small-cell lung cancers. When presentation is by symptoms or incidental discovery, about 50% to 60% of non–small-cell lung cancers are parenchymal nodules or masses, and 40% to 50% are bronchial or hilar. More than 50% of patients with non–small-cell lung cancer will have distant metastases at the time of diagnosis, and only 25%will have potentially resectable disease that can be cured. The overall survival rate at 5 years for lung cancer is approximately 15% and has not significantly improved over the last several decades. The prognosis for lung cancer is af

Postmortem studies of patients who died in the Warsaw Ghetto during World War II suggested that death from starvation was associated with pulmonary emphysema. This study re-examines this hypothesis in patients who are chronically malnourished because of anorexia nervosa. Age, smoking history, body mass index, and pulmonary function were measured in 21 subjects with anorexia nervosa and 16 control subjects. Computed tomography (CT) scans were obtained from three regions of the lung (at the level of the aortic arch, the carina, and the posterior position of the eighth rib) using a multislice scanner. The CT measurements of lung density, emphysema, and surface area-to-volume ratio were obtained using the X-ray attenuation values. CT measurements of emphysema were greater in the group that was anorexic than in historical control subjects (p < 0.001). Furthermore, there were significant correlations between the body mass index and the CT measures of emphysema for all the patients and between diffusing capacity and the CT measurements in the patients who were anorexic. A multiple linear regression analysis showed the diffusing capacity was predicted best by the percentage of lung voxels within the large emphysematous changes category. These data demonstrate that emphysema-like changes are present in the lungs of patients who are chronically malnourished.

Objectives: We sought to test the safety and efficacy of fluoroscopically guided, video-assisted, thoracoscopic resection after computed tomography (CT)-guided localization using platinum microcoils. Summary Background Data: Video-assisted thoracoscopic (VATS) resection of small pulmonary nodules 5 mm deep to the visceral pleura fails to locate the nodule and requires conversion to open thoracotomy in two thirds of cases. Therefore, we developed a new technique for intraoperative localization of these nodules using CTguided placement of platinum microcoils. This study tests the safety and efficacy of this technique in a Phase I human study. Methods: Twelve patients with undiagnosed growing pulmonary nodules 20 mm were marked preoperatively using percutaneously placed CT-guided platinum microcoils. The coil was deployed adjacent to the nodule with the distal end of the coil placed deep to the nodule and the superficial end coiled on the pleural surface. The nodule and coil were excised using endostaplers guided by VATS and fluoroscopy. Histopathologic diagnosis was performed immediately after resection. Results: CT-guided microcoil localization was successful in all patients. A small hemothorax and a pneumothorax requiring a chest tube occurred in 2 patients. Mean distance from visceral pleura to the deep edge of the nodule was 30.9 15.4 mm. VATS resection of the nodules (size 11.8 3.2mm) was successful in all patients. Mean microcoil localization, fluoroscopy, and operative times were 42 14, 3.1 2.0, and 67 27 minutes. A diagnosis of primary nonsmall cell bronchogenic carcinoma was made in 6 patients who then received a completion lobectomy. Six patients (hamartoma: 2, reactive lymph node: 1, bronchoalveolar cell carcinoma: 2, metastatic sarcoma: 1) did not receive further resections. Conclusions: Preoperative localization of pulmonary nodules using percutaneous CT-guided platinum microcoil insertion combined with operative fluoroscopic visualization is a safe, effective technique that increases the success rate of VATS excision.

Thoracic computed tomography (CT) is a sensitive method for detecting early lung cancer but has a high false-positive rate and is not sensitive for detecting central preinvasive and microinvasive cancer. Our hypothesis was that automated quantitative image cytometry (AQC) of sputum cells as the first screening method may improve detection rate by identifying individuals at highest risk for lung cancer. A total of 561 volunteer current or former smokers 50 years of age or older, with a smoking history of more than or equal to 30 pack/years, were studied. Among these, 423 were found to have sputum atypia defined as five cells or more with abnormal DNA content using AQC. Noncalcified pulmonary nodules were found in 46% (259/561). Of the 14 detected cancers, 13 were detected in subjects with sputum atypia-nine by CT and four carcinoma in situ/microinvasive cancers by autofluorescence bronchoscopy. One cancer was detected by CT alone. AQC of sputum cells improved the detection rate of lung cancer from 1.8 to 3.1%. CT scan alone would have missed 29% of the cancers. This screening paradigm shift has the additional potential of reducing the number of initial CT scans by at least 25% with further savings in follow-up investigations and treatment.