Management of an incidentally discovered pulmonary nodule

Frequency and Clinical Significance of Incidental Findings on CBCT Imaging: a Retrospective Analysis of Full-Volume Scans

Objectives

This retrospective study aims to identify incidental findings in cone-beam computed tomography scans of patients irradiated for preoperative evaluation for implant placement and obtained using the same imaging unit as well as the same field of view. The incidence of each incidental finding, as well as the overall incidence, were calculated and the findings were ranked according to their clinical significance.

Material and Methods

A total of 741 cone-beam computed tomography (CBCT) examinations with extended field of view (15 x 15 cm) were retrospectively evaluated for incidental findings (IFs). These were identified, recorded, classified as to their location, and ranked according to their clinical significance.

Results

The vast majority of CBCT examinations presented at least one IF, resulting in a surprisingly high prevalence in total. If extreme anatomical variants are considered (nasal septum deviation, sinus septations etc.), the cumulative prevalence exceeds 99%. IFs of major significance, that may require immediate attention, are beyond 10% in frequency.

Conclusions

We found high prevalence of incidental findings on cone-beam computed tomography examinations performed for preoperative evaluation for implant placement (99.5% if anatomical variants included). Most incidental findings were of minor significance. Although the number of incidental findings that require immediate attention is relatively low, there is a considerable number of cases that need periodic evaluation and/or referral.

Case report: Brucellosis with rare multiple pulmonary nodules in a depressed patient

Background

Brucellosis is a zoonotic disease that threatens public health and creates an economic burden. Unfortunately, it is often overlooked in developing countries, with misdiagnosis causing negative impacts on those with low income. Although the symptoms of brucellosis are commonly reported as fever and fatigue, rare pulmonary, and psychiatric involvements should also be considered. We present the first brucellosis patient in China with multiple pulmonary nodules and depression. Furthermore, this report highlights the importance of collecting patient history in epidemic areas of brucellosis.

Case presentation

We report the case of a 40-year-old woman with intermittent fever for 2 months and gradually accompanied by chills, dry cough, arthralgia, and fatigue. The patient was also diagnosed with depression after fever. She received symptomatic treatment at a regional hospital; however, there was no significant symptom relief. She suddenly developed hemoptysis 1 day prior to arrival at our hospital, where we discovered that her liver, spleen, neck, and axillary lymph nodes were enlarged, and there were multiple nodules in both lungs. The patient was eventually diagnosed with brucellosis after the serum agglutination test and received antibiotic therapy, which provided symptom relief.

Conclusion

This report describes a case of brucellosis with uncommon multipulmonary nodules and depression in China. This study has widened the evidence of respiratory involvement due to brucellosis. Second, it demonstrates the importance of collecting a comprehensive medical history, especially in epidemic areas. In conclusion, for febrile patients with pulmonary nodules and depression, especially in endemic areas, brucellosis should be considered.

Normal blindness: when we Look But Fail To See

Humans routinely miss important information that is 'right in front of our eyes', from overlooking typos in a paper to failing to see a cyclist in an intersection. Recent studies on these 'Looked But Failed To See' (LBFTS) errors point to a common mechanism underlying these failures, whether the missed item was an unexpected gorilla, the clearly defined target of a visual search, or that simple typo. We argue that normal blindness is the by-product of the limited-capacity prediction engine that is our visual system. The processes that evolved to allow us to move through the world with ease are virtually guaranteed to cause us to miss some significant stimuli, especially in important tasks like driving and medical image perception.

Application “Lung Nodule" Software With Lungrads On Early Detection And Follow Up The Pulmonary Nodules By Lung Low Dose CT Findings

Background: A pulmonary nodule is defined as a rounded or irregular opacity, well or poorly defined, measuring up to 3 cm in diameter. Early detection the malignancy of nodules has a significant role in decreasing the mortality, increasing the survival time and consider as early diagnosis lung cancer. Content: The main risk factors are those of current or former smokers, aged 55 to 74 years with a smoking history of at least 1 pack-day. Low dose CT: Screening individuals with high risk of lung cancer by low dose CT scans could reduce lung cancer mortality by 20 percent compared to chest X-ray. Radiation dose has to maximum reduced but respect the rule of ALARA (As Low as Resonably Archivable). ACR-LungRADS 2014: Classification of American College of Radiology, LungRADS, is a newly application but showed many advantages in comparison with others classification such as increasing positive predict value (PPV), no result of false negative and cost effectiveness. “Lung nodule” was applied as a smart phone application in order to have a quickly evaluation, especially the malignancy and management face on a pulmonary nodule.

Visual search errors are persistent in a laboratory analog of the incidental finding problem

When radiologists search for a specific target (e.g., lung cancer), they are also asked to report any other clinically significant “incidental findings” (e.g., pneumonia). These incidental findings are missed at an undesirably high rate. In an effort to understand and reduce these errors, Wolfe et al. (Cognitive Research: Principles and Implications 2:35, 2017) developed “mixed hybrid search” as a model system for incidental findings. In this task, non-expert observers memorize six targets: half of these targets are specific images (analogous to the suspected diagnosis in the clinical task). The other half are broader, categorically defined targets, like “animals” or “cars” (analogous to the less well-specified incidental findings). In subsequent search through displays for any instances of any of the targets, observers miss about one third of the categorical targets, mimicking the incidental finding problem. In the present paper, we attempted to reduce the number of errors in the mixed hybrid search task with the goal of finding methods that could be deployed in a clinical setting. In Experiments 1a and 1b, we reminded observers about the categorical targets by inserting non-search trials in which categorical targets were clearly marked. In Experiment 2, observers responded twice on each trial: once to confirm the presence or absence of the specific targets, and once to confirm the presence or absence of the categorical targets. In Experiment 3, observers were required to confirm the presence or absence of every target on every trial using a checklist procedure. Only Experiment 3 produced a marked decline in categorical target errors, but at the cost of a substantial increase in response time.

Eye Movements in Medical Image Perception: A Selective Review of Past, Present and Future

The eye movements of experts, reading medical images, have been studied for many years. Unlike topics such as face perception, medical image perception research needs to cope with substantial, qualitative changes in the stimuli under study due to dramatic advances in medical imaging technology. For example, little is known about how radiologists search through 3D volumes of image data because they simply did not exist when earlier eye tracking studies were performed. Moreover, improvements in the affordability and portability of modern eye trackers make other, new studies practical. Here, we review some uses of eye movements in the study of medical image perception with an emphasis on newer work. We ask how basic research on scene perception relates to studies of medical 'scenes' and we discuss how tracking experts' eyes may provide useful insights for medical education and screening efficiency.

Automatic Detection and Staging of Lung Tumors using Locational Features and Double-Staged Classifications

Lung cancer is a life-threatening disease with the highest morbidity and mortality rates of any cancer worldwide. Clinical staging of lung cancer can significantly reduce the mortality rate, because effective treatment options strongly depend on the specific stage of cancer. Unfortunately, manual staging remains a challenge due to the intensive effort required. This paper presents a computer-aided diagnosis (CAD) method for detecting and staging lung cancer from computed tomography (CT) images. This CAD works in three fundamental phases: segmentation, detection, and staging. In the first phase, lung anatomical structures from the input tomography scans are segmented using gray-level thresholding. In the second, the tumor nodules inside the lungs are detected using some extracted features from the segmented tumor candidates. In the last phase, the clinical stages of the detected tumors are defined by extracting locational features. For accurate and robust predictions, our CAD applies a double-staged classification: the first is for the detection of tumors and the second is for staging. In both classification stages, five alternative classifiers, namely the Decision Tree (DT), K-nearest neighbor (KNN), Support Vector Machine (SVM), Ensemble Tree (ET), and Back Propagation Neural Network (BPNN), are applied and compared to ensure high classification performance. The average accuracy levels of 92.8% for detection and 90.6% for staging are achieved using BPNN. Experimental findings reveal that the proposed CAD method provides preferable results compared to previous methods; thus, it is applicable as a clinical diagnostic tool for lung cancer.

Evaluation of Serum Paired MicroRNA Ratios for Differential Diagnosis of Non-Small Cell Lung Cancer and Benign Pulmonary Diseases

BACKGROUND AND OBJECTIVE

To clarify whether there are different expressions between lung cancer and benign pulmonary diseases, we studied seven microRNAs (miRNAs) in serum from patients with non-small cell lung cancer (NSCLC), benign pulmonary nodules and four pulmonary inflammation diseases.

METHODS

We detected the expression of miRNAs using quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR).

RESULTS

We found that five miRNA ratios-miR-15b-5p/miR-146b-3p, miR-20a-5p/miR-146b-3p, miR-19a-3p/miR-146b-3p, miR-92a-3p/miR-146b-3p, and miR-16-5p/miR-146b-3p-show higher expression in the NSCLC group than the benign pulmonary nodule group, and 13 ratios of miRNAs were significantly upregulated in the NSCLC group compared with the pulmonary inflammation diseases group. Receiver operating characteristic (ROC) curve analysis was performed. For NSCLC and benign pulmonary nodules, the sensitivity and specificity were 0.70 and 0.90, respectively. For NSCLC and pulmonary inflammation diseases, the sensitivity and specificity were 0.81 and 0.71, respectively.

CONCLUSION

The ratios of miRNAs can be used as potential non-invasive biomarkers for diagnosis of early-stage NSCLC and benign pulmonary diseases.

The clinical significance of indeterminate pulmonary nodules in melanoma patients at baseline and during follow-up chest CT

Objective

This study aims to determine an appropriate timeline to monitor indeterminate pulmonary nodules (IPN) in melanoma patients to confirm metastatic origin.

Materials and Methods

588 clinically non-metastatic melanoma patients underwent curative intent surgery during 3 years. Patients with baseline chest CT and at least one follow-up (FU) CT were retrospectively analyzed to assess for IPN. Patients with definitely benign nodules, metastases and non-melanoma malignancies were excluded. Change in volume from first to FU CT, initial diameter (D1) and volume (V1), distance from pleura, peripheral and perifissural location, density and clinical stage were evaluated. Nodules were volumetrically measured on CTs and were considered metastases if they increased in size between two CTs or if increase was accompanied by multiple new nodules or extrapulmonary metastases.

Results

148 patients were included. Two out of 243 baseline IPN detected in 70 patients, increased significantly in volume in 3 and 5 months and were proven metastases. During FU, 86% of 40 interval IPN detected in 28 patients, were proven metastases. Interval nodule (p < 0.0001, HR:243,CI:[57.32,1033.74]), 3-month volume change (OR:1.023,CI:[1.014,1.033]), V1 (OR:1.006,CI:[1.003,1.009]), D1 (OR:1.424,CI:[1.23,1.648]), distance from pleura (OR:1.03,CI:[1.003,1.059]), and combined stage IIC + III (OR:11.29,CI:[1.514,84.174]), were associated with increased risk for metastasis. 43%, 72% and 94% of patients with IPN were confirmed with metastases in the first FU CT at 3, 6 and 12 months respectively.

Conclusion

Baseline IPN are most likely benign, while interval IPN are high risk for metastasis. Absence of volume increase of IPN within 6 months excluded metastasis in most patients.

Coil Localization-Guided Video-Assisted Thoracoscopic Surgery for Lung Nodules

PURPOSE

To determine the clinical efficacy of preoperative coil localization-guided video-assisted thoracoscopic surgery (VATS) for lung nodules.

MATERIALS AND METHODS

Between November 2015 and July 2017, 56 patients with lung nodules underwent coil localization-guided VATS procedure. The coil implantation was performed under the guidance of computed tomography (CT). The end tail of the coil remained above the visceral pleura. The target lung nodules were removed by VATS wedge resection. Data on the technical success of coil localization and wedge resection, procedure-related complications, and pathological results were collected and analyzed.

RESULTS

Sixty-seven lung nodules in 56 patients (1.2 nodules/case) were localized. The technical success rate of coil localization was 89.6% (60/67). Sixty-three nodules were localized with one coil and four nodules with two coils. The mean time taken to perform CT-guided coil implantation was 15.7 ± 5.3 (range: 8-40) minutes. Six patients (9.0%) experienced pneumothorax after coil implantation. The technical success rate of wedge resection was 97.0% (65/67). Two nodules were removed directly by video-assisted lobectomy. Nine patients with multiple target lung nodules underwent single-stage resection. The mean total operating time was 147.2 ± 79.1 (range: 50-360) minutes. The mean volume of blood loss was 113.2 ± 113.0 (range: 10-700) mL. Postoperative complications included prolonged air leak (n = 2) and pleural effusion (n = 5).

CONCLUSIONS

Preoperative coil localization is a safe and effective method to facilitate a high successful rate of VATS wedge-resection for lung nodules.

How did I miss that? Developing mixed hybrid visual search as a 'model system' for incidental finding errors in radiology

In a real world search, it can be important to keep ‘an eye out’ for items of interest that are not the primary subject of the search. For instance, you might look for the exit sign on the freeway, but you should also respond to the armadillo crossing the road. In medicine, these items are known as “incidental findings,” findings of possible clinical significance that were not the main object of search. These errors (e.g., missing a broken rib while looking for pneumonia) have medical consequences for the patient and potential legal consequences for the physician. Here we report three experiments intended to develop a ‘model system’ for incidental findings – a paradigm that could be used in the lab to develop strategies to reduce incidental finding errors in the clinic. All the experiments involve ‘hybrid’ visual search for any of several targets held in memory. In this ‘mixed hybrid search task,’ observers search for any of three specific targets (e.g., this rabbit, this truck, and this spoon) and three categorical targets (e.g., masks, furniture, and plants). The hypothesis is that the specific items are like the specific goals of a real world search and the categorical targets are like the less well-defined incidental findings that might be present and that should be reported. In all these experiments, varying target prevalence, number of targets, etc., the categorical targets are missed at a much higher rate than the specific targets. This paradigm shows promise as a model of the incidental finding problem.

CT-guided percutaneous hookwire localization increases the efficacy and safety of VATS for pulmonary nodules

BACKGROUND AND OBJECTIVES

The diagnosis of pulmonary nodules of unknown origin is challenging, and such nodules are not always suitable for transthoracic needle biopsy. With the advent of video assisted thoracic surgery (VATS) and CT-guided percutaneous hookwire localization (CT-PHL) we hypothesized that the combination of these two procedures will improve early diagnosis.

METHODS

Selection criteria were a nodule not well approachable with fine needle biopsy and the therapeutic consequences of a diagnosis as assessed by the multidisciplinary oncology board. Efficacy and safety of the combination of CT-PHL prior to VATS was studied in terms of, histological diagnosis, complete resection rate, complications, conversion rate to thoracotomy, and duration of procedures.

RESULTS

A total of 150 pulmonary nodules were located and resected in 150 patients. The median nodule diameter was 9 mm (range 4-24) and located within 30 mm of the pleural surface (median 7, range 0-29). The resection was complete in 96%, and in 100% a definitive histological diagnosis was obtained. Complications requiring intervention during the CT-procedure occurred in 11 patients (7.3%). Complications of VATS consisted of major complications (2.0%) and minor complications (4.0%). The 30 Day mortality was 1.4% and in hospital mortality 0.7%. Conversion to thoracotomy occurred in 4.7% patients. Median CT-localization time was 25 min (range 5-72), median VATS time was 49 min (range 14-169).

CONCLUSIONS

CT-PHL is a very efficient and safe procedure prior to VATS for pulmonary nodules and allows in 96% radical resection with a diagnostic accuracy of 100%.

Incidence of solitary pulmonary nodules in Northeastern France: a population-based study in five regions

Background

The discovery of a solitary pulmonary nodule (SPN) on a chest imaging exam is of major clinical concern. However, the incidence rates of SPNs in a general population have not been estimated. The objective of this study was to provide incidence estimates of SPNs in a general population in 5 northeastern regions of France.

Methods

This population-based study was undertaken in 5 regions of northeastern France in May 2002-March 2003 and May 2004-June 2005. SPNs were identified by chest CT reports collected from all radiology centres in the study area by trained readers using a standardised procedure. All reports for patients at least 18 years old, without a previous history of cancer and showing an SPN between 1 and 3 cm, were included.

Results

A total of 11,705 and 20,075 chest CT reports were collected for the 2002–2003 and 2004–2005 periods, respectively. Among them, 154 and 297 reports showing a SPN were included, respectively for each period. The age-standardised incidence rate (IR) was 10.2 per 100,000 person-years (95% confidence interval 8.5–11.9) for 2002–2003 and 12.6 (11.0–14.2) for 2004–2005. From 2002 to 2005, the age-standardised IR evolved for men from 16.4 (13.2–19.6) to 17.7 (15.0–20.4) and for women from 4.9 (3.2–6.6) to 8.2 (6.4–10.0). In multivariate Poisson regression analysis, gender, age, region and period were significantly associated with incidence variation.

Conclusions

This study provides reference incidence rates of SPN in France. Incidence was higher for men than women, increased with age for both gender and with time for women. Trends in smoking prevalence and improvement in radiological equipment may be related to incidence variations.

Computed Tomography as Primary Screening for Appraisal of Pulmonary Small Nodules in Liver Transplant Candidates

BACKGROUND

Chest computed tomography (CT) as a primary screening method in candidates for living donor liver transplantation (LDLT) is not yet a standardized procedure. The aim of this study is to present our methods and result of evaluation of pulmonary small nodules (PSN) after CT as a primary screening tool.

PATIENTS AND METHODS

A total of 360 primary adult LDLTs were performed between October 2009 and December 2012. The 37 candidates with PSNs found on CT were divided into two groups, with 23 patients in the group that was chest radiography (CXR) positive (+) and 14 in the group that was CXR negative (-).

RESULTS

The nodular size in the CXR (-) group was significantly smaller than in the CXR (+) group (3.86 ± 1.24 vs 7.56 ± 4.08, P = .004). The sensitivity of CT for PSN was 37/360 (10.28%), much higher than the 14/360 (3.89%) for CXR alone. A total of 27 patients underwent video-assisted thoracoscopic surgery for pathologic diagnosis, and 10 were diagnosed as having benign PSNs by stationary sizes on serial CT scans. In the CXR (-) group, there were 2 cases of malignancy, 3 tuberculosis (TB), 3 Cryptococcus, and 15 other benign PS. In the CXR (+) group, there were 1 malignancy, 3 TB, 4 Cryptococcus, and other 6 benign PSNs. Recurrent infection was not seen in the posttransplantation follow-up of 13 candidates with infections. Excluding the 3 malignant PSNs, the 34 candidates in both groups survived 100% for more than 2 years after LDLT.

CONCLUSION

To exclude malignancy and to diagnose infectious PSN for further treatment in a timely manner, chest CT should be used as the primary screening tool for asymptomatic candidates for LDLT.

Community-Based Multidisciplinary Computed Tomography Screening Program Improves Lung Cancer Survival

BACKGROUND

Lung cancer is the most common cause of cancer deaths in the United States. Overall survival is less than 20%, with the majority of patients presenting with advanced disease. The National Lung Screening Trial, performed mainly in academic medical centers, showed that cancer mortality can be reduced with computed tomography (CT) screening compared with chest radiography in high-risk patients. To determine whether this survival advantage can be duplicated in a community-based multidisciplinary thoracic oncology program, we initiated a CT scan screening program for lung cancer within an established health care system.

METHODS

In 2008, we launched a lung cancer CT screening program within the WellStar Health System (WHS) consisting of five hospitals, three health parks, 140 outpatient medical offices, and 12 imaging centers that provide care in a five-county area of approximately 1.4 million people in Metro-Atlanta. Screening criteria incorporated were the International Early Lung Cancer Action Program (2008 to 2010) and National Comprehensive Cancer Network guidelines (2011 to 2013) for moderate- and high-risk patients.

RESULTS

A total of 1,267 persons underwent CT lung cancer screening in WHS from 2008 through 2013; 53% were men, 87% were 50 years of age or older, and 83% were current or former smokers. Noncalcified indeterminate pulmonary nodules were found in 518 patients (41%). Thirty-six patients (2.8%) underwent a diagnostic procedure for positive findings on their CT scan; 30 proved to have cancer, 28 (2.2%) primary lung cancer and 2 metastatic cancer, and 6 had benign disease. Fourteen patients (50%) had their lung cancer discovered on their initial CT scan, 11 on subsequent scans associated with indeterminate pulmonary nodules growth and 3 patients who had a new indeterminate pulmonary nodules. Only 15 (54%) of these 28 patients would have qualified as a National Lung Screening Trial high-risk patient; 75% had stage I or II disease. Overall 5-year survival was 64% and 5-year cancer specific survival was 71% in the screened patients, whereas nonscreened lung cancer patients during that time in WHS had an overall survival of only 19% (p < 0.001).

CONCLUSIONS

A community-based multidisciplinary lung cancer screening program can improve survival of patients with lung cancer outside of a large multicenter study. This survival advantage was caused by a significant stage shift to earlier disease. Lung cancer CT screening may also benefit patients not meeting the National Lung Screening Trial criteria who are at moderate or high risk for lung cancer.

[Management of solid pulmonary nodules]

The increasing availability of computed tomography has meant that the number of incidentally detected solitary pulmonary nodules (SPN) has greatly increased in recent years. A reasonable management of these SPN is necessary in order to firstly be able to detect malignant lesions early on and secondly to avoid upsetting the patient unnecessarily or carrying out further stressful diagnostic procedures. This review article shows how the dignity of SPNs can be estimated and based on this how the management can be accomplished taking established guidelines into consideration.

Evidence based imaging strategies for solitary pulmonary nodule

Solitary pulmonary nodule (SPN) is defined as a rounded opacity ≤3 cm in diameter surrounded by lung parenchyma. The majority of smokers who undergo thin-section CT have SPNs, most of which are smaller than 7 mm. In the past, multiple follow-up examinations over a two-year period, including CT follow-up at 3, 6, 12, 18, and 24 months, were recommended when such nodules are detected incidentally. This policy increases radiation burden for the affected population. Nodule features such as shape, edge characteristics, cavitation, and location have not yet been found to be accurate for distinguishing benign from malignant nodules. When SPN is considered to be indeterminate in the initial exam, the risk factor of the patients should be evaluated, which includes patients' age and smoking history. The 2005 Fleischner Society guideline stated that at least 99% of all nodules 4 mm or smaller are benign; when nodule is 5-9 mm in diameter, the best strategy is surveillance. The timing of these control examinations varies according to the nodule size (4-6, or 6-8 mm) and the type of patients, specifically at low or high risk of malignancy concerned. Noncalcified nodules larger than 8 mm diameter bear a substantial risk of malignancy, additional options such as contrast material-enhanced CT, positron emission tomography (PET), percutaneous needle biopsy, and thoracoscopic resection or videoassisted thoracoscopic resection should be considered.

Comparison of three software systems for semi-automatic volumetry of pulmonary nodules on baseline and follow-up CT examinations

BACKGROUND

Early diagnosis of lung cancer in a treatable stage is the main purpose of lung cancer screening by computed tomography (CT). Accurate three-dimensional size and growth measurements are essential to assess the risk of malignancy. Nodule volumes can be calculated by using semi-automated volumetric software. Systematic differences in volume measurements between packages could influence nodule categorization and management decisions.

PURPOSE

To compare volumetric measurements of solid pulmonary nodules on baseline and follow-up CT scans as well as the volume doubling time (VDT) for three software packages.

MATERIAL AND METHODS

From a Lung Cancer Screening study (NELSON), 50 participants were randomly selected from the baseline round. The study population comprised participants with at least one pulmonary nodule at the baseline and consecutive CT examination. The volume of each nodule was determined for both time points using three semi-automated software packages (P1, P2, and P3). Manual modification was performed when automated assessment was visually inaccurate. VDT was calculated to evaluate nodule growth. Volume, VDT, and nodule management were compared for the three software packages, using P1 as the reference standard.

RESULTS

In 25 participants, 147 nodules were present on both examinations (volume: 12.0-436.6 mm(3)). Initial segmentation at baseline was evaluated to be satisfactory in 93.9% of nodules for P1, 84.4 % for P2, and 88.4% for P3. Significant difference was found in measured volume between P1 and the other two packages (P < 0.001). P2 overestimated the volume by 38 ± 24%, and P3 by 50 ± 22%. At baseline, there was consensus on nodule size categorization in 80% for P1&P2 and 74% for P1&P3. At follow-up, consensus on VDT categorization was present in 47% for P1&P2 and 44% for P1&P3.

CONCLUSION

Software packages for lung nodule evaluation yield significant differences in volumetric measurements and VDT. This variation affects the classification of lung nodules, especially in follow-up examinations.

Early diagnosis of solitary pulmonary nodules

Early detection of solitary pulmonary nodules (SPNs) and early treatment are of great importance. However, patients with early SPNs always do not present with any symptoms or signs, only to demonstrate SPNs in radiology findings. So it is very critical to improve the ability to identify the SPNs, and with the development of sorts of diagnostic modalities, the accuracy in the evaluation of the SPNs has improved greatly. In this paper, the diagnostic methods and techniques of SPNs are reviewed.

Indeterminate lung nodules in cancer patients: pretest probability of malignancy and the role of 18F-FDG PET/CT

OBJECTIVE

The purpose of this study was to determine likelihood of malignancy for indeterminate lung nodules identified on CT comparing two standardized models with (18)F-FDG PET/CT.

MATERIALS AND METHODS

Fifty-nine cancer patients with indeterminate lung nodules (solid tumors; diameter, ≥5 mm) on CT had FDG PET/CT for lesion characterization. Mayo Clinic and Veterans Affairs Cooperative Study models of likelihood of malignancy were applied to solitary pulmonary nodules. High probability of malignancy was assigned a priori for multiple nodules. Low (<5%), intermediate (5-60%), and high (>60%) pretest malignancy probabilities were analyzed separately. Patients were reclassified with PET/CT. Histopathology or 2-year imaging follow-up established diagnosis. Outcome-based reclassification differences were defined as net reclassification improvement. A null hypothesis of asymptotic test was applied.

RESULTS

Thirty-one patients had histology-proven malignancy. PET/CT was true-positive in 24 and true-negative in 25 cases. Negative predictive value was 78% and positive predictive value was 89%. On the basis of the Mayo Clinic model (n=31), 18 patients had low, 12 had intermediate, and one had high pretest likelihood; on the basis of the Veterans Affairs model (n=26), 5 patients had low, 20 had intermediate, and one had high pretest likelihood. Because of multiple lung nodules, 28 patients were classified as having high malignancy risk. PET/CT showed 32 negative and 27 positive scans. Net reclassification improvements respectively were 0.95 and 1.6 for Mayo Clinic and Veterans Affairs models (both p<0.0001). Fourteen of 31 (45.2%) and 12 of 26 (46.2%) patients with low and intermediate pretest likelihood, respectively, had positive findings on PET/CT for the Mayo Clinic and Veterans Affairs models, respectively. Of 15 patients with high pretest likelihood and negative findings on PET/CT, 13 (86.7%) did not have lung malignancy.

CONCLUSION

PET/CT improves stratification of cancer patients with indeterminate pulmonary nodules. A substantial number of patients considered at low and intermediate pretest likelihood of malignancy with histology-proven lung malignancy showed abnormal PET/CT findings.

Small irregular pulmonary nodules in low-dose CT: observer detection sensitivity and volumetry accuracy

OBJECTIVE

The purpose of this study is to evaluate observer detection and volume measurement of small irregular solid artificial pulmonary nodules on 64-MDCT in an anthropomorphic thoracic phantom.

MATERIALS AND METHODS

Forty in-house-made solid pulmonary nodules (lobulated and spiculated; actual volume, 5.1-88.4 mm3; actual CT densities, -51 to 157 HU) were randomly placed inside an anthropomorphic thoracic phantom with pulmonary vasculature. The phantom was examined on two 64-MDCT scanners, using a scan protocol as applied in lung cancer screening. Two independent blinded observers screened for pulmonary nodules. Nodule volume was evaluated semiautomatically using dedicated software and was compared with the actual volume using an independent-samples t test. The interscanner and interobserver agreement of volumetry was assessed using Bland-Altman analysis.

RESULTS

Observer detection sensitivity increased along with increasing size of irregular nodules. Sensitivity was 100% when the actual volume was at least 69 mm3, regardless of specific observer, scanner, nodule shape, and density. Overall, nodule volume was underestimated by (mean±SD) 18.9±11.8 mm3 (39%±21%; p<0.001). The relative interscanner difference of volumetry was 3.3% (95% CI, -33.9% to 40.4%). The relative interobserver difference was 0.6% (-33.3% to 34.5%).

CONCLUSION

Small irregular solid pulmonary nodules with an actual volume of at least 69 mm3 are reliably detected on 64-MDCT. However, CT-derived volume of those small nodules is largely underestimated, with considerable variation.

[Diagnosis and management of solitary pulmonary nodules]

目前，肺癌已跃居成为我国发病率及死亡率最高的恶性肿瘤，总体5年生存率较低；早诊早治是提高肺癌患者生存率及改善预后的关键，而早期肺癌患者常无任何症状和体征，只在影像学上表现为肺孤立性结节病变。提高对孤立性肺结节良恶性的鉴别诊断能力是临床诊治过程中的难点与热点。随着各种诊治技术的发展，孤立性肺结节病变性质的诊断准确率已大大提高。

Geriatric chest imaging: when and how to image the elderly lung, age-related changes, and common pathologies

Even in a global perspective, societies are getting older. We think that diagnostic lung imaging of older patients requires special knowledge. Imaging strategies have to be adjusted to the needs of frail patients, for example, immobility, impossibility for long breath holds, renal insufficiency, or poor peripheral venous access. Beside conventional radiography, modern multislice computed tomography is the method of choice in lung imaging. It is especially important to separate the process of ageing from the disease itself. Pathologies with a special relevance for the elderly patient are discussed in detail: pneumonia, aspiration pneumonia, congestive heart failure, chronic obstructive pulmonary disease, the problem of overlapping heart failure and chronic obstructive pulmonary disease, pulmonary drug toxicity, incidental pulmonary embolism pulmonary nodules, and thoracic trauma.

Indeterminate pulmonary nodules at colorectal cancer staging: a systematic review of predictive parameters for malignancy

BACKGROUND

This study aimed to estimate the prevalence of indeterminate pulmonary nodules and specific radiological and clinical characteristics that predict malignancy of these at initial staging chest computed tomography (CT) in patients with colorectal cancer. A considerable number of indeterminate pulmonary nodules, which cannot readily be classified as either benign or malignant, are detected at initial staging chest CT in colorectal cancer patients.

METHODS

A systematic review based on a search in EMBASE, Medline, the Cochrane library and science citation index, PubMed databases, Google scholar, and relevant conference proceedings was performed in cooperation with the Cochrane Colorectal Cancer Group.

RESULTS

A total of 2,799 studies were identified, of which 12 studies met the inclusion criteria. The studies primarily consisted of case series and included a total of 5,873 patients. Of these patients, 9% (95% confidence interval [95% CI] 8.9-9.2%) had indeterminate pulmonary nodules at chest CT, of which 10.8% (95% CI 10.3-11.2%) turned out to be colorectal cancer metastases at follow-up. Generally, regional lymph node metastasis, and multiple numbers of indeterminate pulmonary nodules were reported to predict malignancy, whereas calcification of the nodules indicated benign lesions.

CONCLUSION

It was found that 1 in 100 colorectal cancer patients subjected to preoperative staging chest CT will have an indeterminate pulmonary nodule that proves to be metastatic disease. Such a low risk suggests that indeterminate pulmonary nodules should not cause further preoperative diagnostic workup or follow-up besides routine regimens.

Comparison of dual-energy subtraction and electronic bone suppression combined with computer-aided detection on chest radiographs: effect on human observers' performance in nodule detection

OBJECTIVE

The objective of our study was to compare the effect of dual-energy subtraction and bone suppression software alone and in combination with computer-aided detection (CAD) on the performance of human observers in lung nodule detection.

MATERIALS AND METHODS

One hundred one patients with from one to five lung nodules measuring 5-29 mm and 42 subjects with no nodules were retrospectively selected and randomized. Three independent radiologists marked suspicious-appearing lesions on the original chest radiographs, dual-energy subtraction images, and bone-suppressed images before and after postprocessing with CAD. Marks of the observers and CAD marks were compared with CT as the reference standard. Data were analyzed using nonparametric tests and the jackknife alternative free-response receiver operating characteristic (JAFROC) method.

RESULTS

Using dual-energy subtraction alone (p = 0.0198) or CAD alone (p = 0.0095) improved the detection rate compared with using the original conventional chest radiograph. The combination of bone suppression and CAD provided the highest sensitivity (51.6%) and the original nonenhanced conventional chest radiograph alone provided the lowest (46.9%; p = 0.0049). Dual-energy subtraction and bone suppression provided the same false-positive (p = 0.2702) and true-positive (p = 0.8451) rates. Up to 22.9% of lesions were found only by the CAD program and were missed by the readers. JAFROC showed no difference in the performance between modalities (p = 0.2742-0.5442).

CONCLUSION

Dual-energy subtraction and the electronic bone suppression program used in this study provided similar detection rates for pulmonary nodules. Additionally, CAD alone or combined with bone suppression can significantly improve the sensitivity of human observers for pulmonary nodule detection.

The role of dynamic magnetic resonance imaging in the evaluation of pulmonary nodules and masses

OBJECTIVE

The aim of our study was to determine whether or not dynamic magnetic resonance imaging (MRI) with kinetic and morphological parameters can reveal significant differences between malignant and benign pulmonary lesions, and thus to evaluate the use of dynamic MRI in the management of pulmonary nodules.

PATIENTS AND METHODS

Thirty-one patients (4 women and 27 men) underwent 1.5 T MRI, where 10 consecutive dynamic series were performed every 30 s by using 3D fast low-angle shot sequences. The percentage increase in the signal intensity of the lesions was determined for each time point. Time-enhancement curves of the lesions were drawn and classified into four types: A, B, C and D. Early peak (EP) and maximum peak (MP) values of the curves were calculated and compared with the diagnoses of the patients. The usefulness of these parameters was tested statistically. In addition to the comparison of the parameters between the groups, receiver-operating characteristic analysis was used to assess sensitivity, specificity, and both positive and negative predictive values of EP and MP parameters.

RESULTS

Of the 31 pulmonary lesions, 16 (52%) were malignant. These showed a stronger enhancement with higher median values of EP and MP (77.08 and 123.15, respectively) than those corresponding to the benign lesions (14.45 and 32.53, respectively). There were significant differences between the benign and malignant lesions (p < 0.001). Sensitivity, specificity, positive predictive value and negative predictive value were 75, 93, 92 and 78% for EP and 93, 86, 88 and 93% for MP, respectively.

CONCLUSION

A combination of kinetic and morphological evaluation in dynamic MRI provided accurate differentiation between benign and malignant pulmonary lesions. It was a useful and noninvasive method of evaluating pulmonary nodules.

Followup of a solid solitary pulmonary nodule with low metabolic activity

An incidentally found solid solitary pulmonary nodule (SPN) was studied using FDG PET/CT. The SPN (at that time 11mm) showed only minimal FDG uptake, with a maximum standardized uptake value of 1.7 (max SUV). This suggested a benign lesion. When followup CT was performed six months later, the SPN had grown to 12mm. The patient was re-examined by FDG PET/CT five months later to exclude malignancy. The SPN was now FDG avid, and its size was 14mm. The max SUV was 12.7, consistent with a malignant disease. The patient underwent surgery, and histological examination demonstrated a solid adenocarcinoma (gradus III). The increase in glucose metabolism can be attributed to a change in the histopathologic subtype or molecular features of the SPN. The importance of a followup of nonmetabolically active SPNs is emphasized, primarily by CT (due to its convenience and low cost).

Pulmonary staging in colorectal cancer: a review

AIM

Assessment of the chest in colorectal cancer (CRC) staging is variable. The aim of this review was to look at different chest staging strategies and determine which has the greatest efficacy.

METHOD

A review of studies assessing chest staging modalities for patients with CRC was performed. Modalities included chest X-ray (CXR), CT and positron emission tomography (PET).

RESULTS

The majority of data consisted of case series. Two studies identified a low pick-up rate for CXR as a staging tool. Five studies showed increased detection rates of pulmonary metastases for chest CT vs CXR and abdominal CT. The clinical benefit of the increased detection rates was not clear. The incidence of indeterminate lung lesions (ILL) on staging chest CT varied from 4 to 42%. The majority (≥ 70%) of ILLs did not have any clinical significance. On CT scans, the incidence of pulmonary metastases in patients with rectal cancer ranged from 10 to 18% and in patients with colon cancer the incidence of pulmonary metastases ranged from 5-6%. The incidence of synchronous liver and pulmonary metastases compared with the overall incidence of pulmonary metastases ranged from 45 to 70%. There was no evidence reporting the superiority of PET/CT vs CT for the detection of pulmonary metastases or characterization of ILL.

CONCLUSION

Studies show that chest CT scanning increases the detection rates for ILL and pulmonary metastases. The clinical benefit of the increased detection rates is not clear. There is a paucity of data assessing the optimal chest staging strategy for patients presenting with CRC.

Indeterminate pulmonary nodules in rectal cancer: a recommendation for follow-up guidelines

BACKGROUND

Incidental visualization of indeterminate pulmonary nodules is considered a clinical dilemma.

METHODS

We identified patients for inclusion in this study by searching for the term "indeterminate nodules" in the radiology database of rectal cancer patients who underwent surgery. Patients with definite metastatic disease were excluded.

RESULTS

In total, 224 patients underwent chest computerized tomography (CT) and 59 of these patients had indeterminate pulmonary nodules detected more than twice by CT scan. Six patients (10.2%) were confirmed to have metastatic lesions on follow-up evaluation. Pulmonary nodule size (P=0.028), pathologic N status (P=0.049), positive nodal status (P=0.036) and the number of positive lymph nodes (P=0.033) were significant risk factors for pulmonary metastasis. In the pulmonary metastasis group, the patients who had received adjuvant oxaliplatin-based (FOLFOX4) chemotherapy had longer intervals to developing metastasis compared to patients who had not received it.

CONCLUSIONS

It is not necessary to perform excessive surveillance routinely for all rectal cancer patients who have indeterminate pulmonary lesions. Intensive follow-up chest CT or other invasive diagnostic modalities should be considered only in patients with pulmonary nodules larger than 5.7 mm or positive nodal status. In addition, patients receiving adjuvant FOLFOX4 chemotherapy should be followed-up for longer periods.

Computed tomographic criteria for the discrimination of subcentimeter lung nodules in patients with soft-tissue sarcomas

The aim of this study was to identify criteria for nodule characterization on chest computed tomography in patients with soft tissue sarcomas. In 195 patients, a total of 194 benign and 117 malignant subcentimeter lung nodules were retrospectively analyzed according to lesion size, shape, margins, density, and localization. Benign lesions more frequently displayed complex shape and were of ground-glass density (P<.0001, respectively). In contrast, round shape and solid density were more frequently found in malignant lesions (P<.0001, respectively).

Diagnosis of lung cancer in individuals with solitary pulmonary nodules by plasma microRNA biomarkers

Background

Making a definitive preoperative diagnosis of solitary pulmonary nodules (SPNs) found by CT has been a clinical challenge. We previously demonstrated that microRNAs (miRNAs) could be used as biomarkers for lung cancer diagnosis. Here we investigate whether plasma microRNAs are useful in identifying lung cancer among individuals with CT-detected SPNs.

Methods

By using quantitative reverse transcriptase PCR analysis, we first determine plasma expressions of five miRNAs in a training set of 32 patients with malignant SPNs, 33 subjects with benign SPNs, and 29 healthy smokers to define a panel of miRNAs that has high diagnostic efficiency for lung cancer. We then validate the miRNA panel in a testing set of 76 patients with malignant SPNs and 80 patients with benign SPNs.

Results

In the training set, miR-21 and miR-210 display higher plasma expression levels, whereas miR-486-5p has lower expression level in patients with malignant SPNs, as compared to subjects with benign SPNs and healthy controls (all P ≤ 0.001). A logistic regression model with the best prediction was built on the basis of miR-21, miR-210, and miR-486-5p. The three miRNAs used in combination produced the area under receiver operating characteristic curve at 0.86 in distinguishing lung tumors from benign SPNs with 75.00% sensitivity and 84.95% specificity. Validation of the miRNA panel in the testing set confirms their diagnostic value that yields significant improvement over any single one.

Conclusions

The plasma miRNAs provide potential circulating biomarkers for noninvasively diagnosing lung cancer among individuals with SPNs, and could be further evaluated in clinical trials.

[Conventional and CT diagnostics of bronchial carcinoma]

A number of important technical advances made in recent years in the area of both digital radiography as well as multidetector computed tomography (MDCT) have improved detection and staging of bronchial carcinoma. The aim of elaborate processing such as temporal subtraction, rib suppression, dual energy subtraction or CAD is to aid the radiologist in detecting lung tumors at the earliest stage possible. For both CT and radiography techniques the differentiation between true and false positive lesions seems to be the biggest challenge. MDCT with multiplanar projections is the imaging method of choice for staging of the extent of local tumor spread (T staging), while N staging and M staging are the domain of positron emission tomography (PET) or even better of integrated PET/CT. Management rules for follow-up of solid and semi-solid lesions seen in CT consider the risks of the patient and are summarized in international guidelines. In 2009 a new 7th edition of the TNM classification was published, which, among other aspects, sub-classifies tumor size more specifically and the presence of a satellite nodule in the tumor lobe is down-staged to T3 and no longer determines tumor resectability. The N staging was not modified. One of the most important new features is the fact that the new classification no longer applies only to non-small cell lung cancer (NSCLC) but also to SCLC and carcinoid tumors.

Incidental findings in imaging diagnostic tests: a systematic review

The objective of this review is to summarise the available evidence on the frequency and management of incidental findings in imaging diagnostic tests. Original articles were identified by a systematic search of the MEDLINE, EMBASE and Cochrane Library Plus databases using appropriate medical headings. Extracted variables were study design; sample size; type of imaging test; initial diagnosis; frequency and location of incidental findings; whether clinical follow-up was performed; and whether a definitive diagnosis was made. Study characteristics were assessed by one reviewer and checked by a second reviewer. Any disagreement was solved by consensus. The relationship between the frequency of incidental findings and the study characteristics was assessed using a one-way ANOVA test, as was the frequency of follow-up of incidental findings and the frequency of confirmation. 251 potentially relevant abstracts were identified and 44 articles were finally included in the review. Overall, the mean frequency of incidental findings was 23.6% (95% confidence interval (CI) 15.8-31.3%). The frequency of incidental findings was higher in studies involving CT technology (mean 31.1%, 95% CI 20.1-41.9%), in patients with an unspecific initial diagnosis (mean 30.5, 95% CI 0-81.6) and when the location of the incidental findings was unspecified (mean 33.9%, 95% CI 18.1-49.7). The mean frequency of clinical follow-up was 64.5% (95% CI 52.9-76.1%) and mean frequency of clinical confirmation was 45.6% (95% CI 32.1-59.2%). Although the optimal strategy for the management of these abnormalities is still unclear, it is essential to be aware of the low clinical confirmation in findings of moderate and major importance.

[Characterization and management of incidentally detected solitary pulmonary nodules]

How to deal with solitary pulmonary nodules (SPN) which are incidentally detected by computed tomography (CT) is an increasingly important task in the era of modern multislice CT. This paper reviews the morphological and functional characteristics and their value for discrimination between benign and malignant SPNs. In particular, the importance of nodule size, growth rate, margin morphology, density, calcifications or fatty components within the nodules, the significance of cavitations or aerobronchograms, enhancement patterns at dynamic contrast-enhanced CT and findings on positron emission tomography (PET) are discussed. The Bayesian analysis to calculate the probability of malignancy is presented. Finally, flow charts demonstrate the national and international recommendations for nodule management.

[Localized pure or mixed ground-glass lung opacities]

Localized ground-glass opacities (GGOs) have been recently individualized and account for between 2.9% and 19% of all pulmonary nodules detected in high-risk patients included in CT screening series for lung cancer. These opacities, nodular, lobular or flat, correspond to benign lesions (localised infectious and inflammatory diseases, focal interstitial fibrosis, and atypical alveolar hyperplasia) or malignant lesions (bronchioloalveolar carcinoma, early-stage adenocarcinoma and sometimes metastases). Localized GGOs are more likely to be malignant than solid nodules and prognosis is related to the percentage of the ground-glass component. However, doubling time of pure localized malignant GGOs is longer than mixed localized malignant GGOs and even longer than the doubling time of solid malignant nodules. Therefore, localized GGOs warrant a dedicated diagnostic workup.

Improved detection of pulmonary nodules on energy-subtracted chest radiographs with a commercial computer-aided diagnosis software: comparison with human observers

OBJECTIVE

To retrospectively analyze the performance of a commercial computer-aided diagnosis (CAD) software in the detection of pulmonary nodules in original and energy-subtracted (ES) chest radiographs.

METHODS

Original and ES chest radiographs of 58 patients with 105 pulmonary nodules measuring 5-30 mm and images of 25 control subjects with no nodules were randomized. Five blinded readers evaluated firstly the original postero-anterior images alone and then together with the subtracted radiographs. In a second phase, original and ES images were analyzed by a commercial CAD program. CT was used as reference standard. CAD results were compared to the readers' findings. True-positive (TP) and false-positive (FP) findings with CAD on subtracted and non-subtracted images were compared.

RESULTS

Depending on the reader's experience, CAD detected between 11 and 21 nodules missed by readers. Human observers found three to 16 lesions missed by the CAD software. CAD used with ES images produced significantly fewer FPs than with non-subtracted images: 1.75 and 2.14 FPs per image, respectively (p = 0.029). The difference for the TP nodules was not significant (40 nodules on ES images and 34 lesions in non-subtracted radiographs, p = 0.142).

CONCLUSION

CAD can improve lesion detection both on energy subtracted and non-subtracted chest images, especially for less experienced readers. The CAD program marked less FPs on energy-subtracted images than on original chest radiographs.

Chest tomosynthesis: technical principles and clinical update

Digital tomosynthesis is a radiographic technique that can produce an arbitrary number of section images of a patient from a single pass of the X-ray tube. It utilizes a conventional X-ray tube, a flat-panel detector, a computer-controlled tube mover, and special reconstruction algorithms to produce section images. While it does not have the depth resolution of computed tomography (CT), tomosynthesis provides some of the tomographic benefits of CT but at lower cost and radiation dose than CT. Compared to conventional chest radiography, chest tomosynthesis results in improved visibility of normal structures such as vessels, airway and spine. By reducing visual clutter from overlying normal anatomy, it also enhances detection of small lung nodules. This review article outlines the components of a tomosynthesis system, discusses results regarding improved lung nodule detection from the recent literature, and presents examples of nodule detection from a clinical trial in human subjects. Possible implementation strategies for use in clinical chest imaging are discussed.