Managing the Small Pulmonary Nodule Discovered by CT

Deep learning in pulmonary nodule detection and segmentation: a systematic review

OBJECTIVES

The accurate detection and precise segmentation of lung nodules on computed tomography are key prerequisites for early diagnosis and appropriate treatment of lung cancer. This study was designed to compare detection and segmentation methods for pulmonary nodules using deep-learning techniques to fill methodological gaps and biases in the existing literature.

METHODS

This study utilized a systematic review with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, searching PubMed, Embase, Web of Science Core Collection, and the Cochrane Library databases up to May 10, 2023. The Quality Assessment of Diagnostic Accuracy Studies 2 criteria was used to assess the risk of bias and was adjusted with the Checklist for Artificial Intelligence in Medical Imaging. The study analyzed and extracted model performance, data sources, and task-focus information.

RESULTS

After screening, we included nine studies meeting our inclusion criteria. These studies were published between 2019 and 2023 and predominantly used public datasets, with the Lung Image Database Consortium Image Collection and Image Database Resource Initiative and Lung Nodule Analysis 2016 being the most common. The studies focused on detection, segmentation, and other tasks, primarily utilizing Convolutional Neural Networks for model development. Performance evaluation covered multiple metrics, including sensitivity and the Dice coefficient.

CONCLUSIONS

This study highlights the potential power of deep learning in lung nodule detection and segmentation. It underscores the importance of standardized data processing, code and data sharing, the value of external test datasets, and the need to balance model complexity and efficiency in future research.

CLINICAL RELEVANCE STATEMENT

Deep learning demonstrates significant promise in autonomously detecting and segmenting pulmonary nodules. Future research should address methodological shortcomings and variability to enhance its clinical utility.

KEY POINTS

Deep learning shows potential in the detection and segmentation of pulmonary nodules. There are methodological gaps and biases present in the existing literature. Factors such as external validation and transparency affect the clinical application.

Deep learning for malignancy risk estimation of incidental sub-centimeter pulmonary nodules on CT images

OBJECTIVES

To establish deep learning models for malignancy risk estimation of sub-centimeter pulmonary nodules incidentally detected by chest CT and managed in clinical settings.

MATERIALS AND METHODS

Four deep learning models were trained using CT images of sub-centimeter pulmonary nodules from West China Hospital, internally tested, and externally validated on three cohorts. The four models respectively learned 3D deep features from the baseline whole lung region, baseline image patch where the nodule located, baseline nodule box, and baseline plus follow-up nodule boxes. All regions of interest were automatically segmented except that the nodule boxes were additionally manually checked. The performance of models was compared with each other and that of three respiratory clinicians.

RESULTS

There were 1822 nodules (981 malignant) in the training set, 806 (416 malignant) in the testing set, and 357 (253 malignant) totally in the external sets. The area under the curve (AUC) in the testing set was 0.754, 0.855, 0.928, and 0.942, respectively, for models derived from baseline whole lung, image patch, nodule box, and the baseline plus follow-up nodule boxes. When baseline models externally validated (follow-up images not available), the nodule-box model outperformed the other two with AUC being 0.808, 0.848, and 0.939 respectively in the three external datasets. The resident, junior, and senior clinicians achieved an accuracy of 67.0%, 82.5%, and 90.0%, respectively, in the testing set. The follow-up model performed comparably to the senior clinician.

CONCLUSION

The deep learning algorithms solely mining nodule information can efficiently predict malignancy of incidental sub-centimeter pulmonary nodules.

CLINICAL RELEVANCE STATEMENT

The established models may be valuable for supporting clinicians in routine clinical practice, potentially reducing the number of unnecessary examinations and also delays in diagnosis.

KEY POINTS

• According to different regions of interest, four deep learning models were developed and compared to evaluate the malignancy of sub-centimeter pulmonary nodules by CT images. • The models derived from baseline nodule box or baseline plus follow-up nodule boxes demonstrated sufficient diagnostic accuracy (86.4% and 90.4% in the testing set), outperforming the respiratory resident (67.0%) and junior clinician (82.5%). • The proposed deep learning methods may aid clinicians in optimizing follow-up recommendations for sub-centimeter pulmonary nodules and may lead to fewer unnecessary diagnostic interventions.

Accuracy of CT-Guided Core-Needle Biopsy in Diagnosis of Thoracic Lesions Suspicious for Primitive Malignancy of the Lung: A Five-Year Retrospective Analysis

BACKGROUND

Lung cancer represents a heterogeneous group of neoplasms, with the highest frequency and mortality in both sexes combined. In a clinical scenario characterized by the widespread of multidetector-row spiral CT, core-needle biopsy under tomographic guidance is one of the main and safest methods to obtain tissue specimens, even though there are relatively high rates of pneumothorax (0-60% incidence) and pulmonary hemorrhage (4-27% occurrence rates). The aim of this retrospective study is to assess the diagnostic accuracy of CT-guided core-needle biopsy in the diagnosis of primary lung malignancies and to compare our results with evidence from the literature.

MATERIALS AND METHODS

Our analysis included 350 thoracic biopsies, performed from 2017 to 2022 with a 64-row CT guidance and 16/18 G needles mounted on a biopsy gun. We included in the final cohort all samples with evidence of primary lung malignancies, precursor lesions, and atypia, as well as inconclusive and negative diagnoses.

RESULTS

There was sensitivity of 90.07% (95% CI 86.05-93.25%), accuracy of 98.87% (95% CI 98.12-99.69%), positive predictive value of 100%, and negative value of 98.74% (95% CI 98.23-99.10%). Specificity settled at 100% (93.84-100%). The AUC was 0.952 (95% CI 0.924-0.972). Only three patients experienced major complications after the procedure. Among minor complications, longer distances from the pleura, the presence of emphysema, and the lower dimensions of the lesions were correlated with the development of pneumothorax after the procedure, while longer distances from the pleura and the lower dimensions of the lesions were correlated with intra-alveolar hemorrhage. Immunohistochemistry analysis was performed in 51% of true positive cases, showing TTF-1, CK7, and p40 expression, respectively, in 26%, 24%, and 10% of analyzed samples.

CONCLUSIONS

The CT-guided thoracic core-needle biopsy is an extremely accurate and safe diagnostic procedure for the histological diagnosis of lung cancer, a first-level interventional radiology exam for peripheral and subpleural lesions of the lung, which is also able to provide adequate samples for advanced pathologic assays (e.g., FISH, PCR) to assess molecular activity and genetic sequencing.

Applying Compressed Sensing Volumetric Interpolated Breath-Hold Examination and Spiral Ultrashort Echo Time Sequences for Lung Nodule Detection in MRI

This prospective study aimed to investigate the ability of spiral ultrashort echo time (UTE) and compressed sensing volumetric interpolated breath-hold examination (CS-VIBE) sequences in magnetic resonance imaging (MRI) compared to conventional VIBE and chest computed tomography (CT) in terms of image quality and small nodule detection. Patients with small lung nodules scheduled for video-assisted thoracoscopic surgery (VATS) for lung wedge resection were prospectively enrolled. Each patient underwent non-contrast chest CT and non-contrast MRI on the same day prior to thoracic surgery. The chest CT was performed to obtain a standard reference for nodule size, location, and morphology. The chest MRI included breath-hold conventional VIBE and CS-VIBE with scanning durations of 11 and 13 s, respectively, and free-breathing spiral UTE for 3.5–5 min. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and normal structure visualizations were measured to evaluate MRI quality. Nodule detection sensitivity was evaluated on a lobe-by-lobe basis. Inter-reader and inter-modality reliability analyses were performed using the Cohen κ statistic and the nodule size comparison was performed using Bland–Altman plots. Among 96 pulmonary nodules requiring surgery, the average nodule diameter was 7.7 ± 3.9 mm (range: 4–20 mm); of the 73 resected nodules, most were invasive cancer (74%) or pre-invasive carcinoma in situ (15%). Both spiral UTE and CS-VIBE images achieved significantly higher overall image quality scores, SNRs, and CNRs than conventional VIBE. Spiral UTE (81%) and CS-VIBE (83%) achieved a higher lung nodule detection rate than conventional VIBE (53%). Specifically, the nodule detection rate for spiral UTE and CS-VIBE reached 95% and 100% for nodules >8 and >10 mm, respectively. A 90% detection rate was achieved for nodules of all sizes with a part-solid or solid morphology. Spiral UTE and CS-VIBE under-estimated the nodule size by 0.2 ± 1.4 mm with 95% limits of agreement from −2.6 to 2.9 mm and by 0.2 ± 1.7 mm with 95% limits of agreement from −3.3 to 3.5 mm, respectively, compared to the reference CT. In conclusion, chest CT remains the gold standard for lung nodule detection due to its high image resolutions. Both spiral UTE and CS-VIBE MRI could detect small lung nodules requiring surgery and could be considered a potential alternative to chest CT; however, their clinical application requires further investigation.

After All, It was Not Lung Cancer: When The Evidence is Misleading

The aetiology of pulmonary nodules is varied, with malignant lesions being the most important and requiring rapid diagnosis and treatment. However, although clinical presentation and imaging may suggest a specific diagnosis, it should be kept in mind that some benign pathologies mimic more serious disease. A 50-year-old man presented with left pleuritic chest pain. A CT scan showed an ipsilateral pulmonary spiculated nodule. Pneumonia was assumed and the patient was started on antibiotic therapy. In the absence of improvement, positron emission tomography and a transthoracic aspiration biopsy were performed. Lung cancer was diagnosed and the patient underwent an upper lobectomy. However, examination of the surgical specimen showed no malignancy.

LEARNING POINTS

Although complementary diagnostic exams are increasingly available and widely used, they may produce false positive or false negative results.A correct diagnostic approach can lead to an incorrect diagnosis.The preoperative diagnosis of pulmonary nodules can be a challenge.

The Regimen of Computed Tomography Screening for Lung Cancer: Lessons Learned Over 25 Years From the International Early Lung Cancer Action Program

We learned many unanticipated and valuable lessons since we started planning our study of low-dose computed tomography (CT) screening for lung cancer in 1991. The publication of the baseline results of the Early Lung Cancer Action Project (ELCAP) in Lancet 1999 showed that CT screening could identify a high proportion of early, curable lung cancers. This stimulated large national screening studies to be quickly started. The ELCAP design, which provided evidence about screening in the context of a clinical program, was able to rapidly expand to a 12-institution study in New York State (NY-ELCAP) and to many international institutions (International-ELCAP), ultimately working with 82 institutions, all using the common I-ELCAP protocol. This expansion was possible because the investigators had developed the ELCAP Management System for screening, capturing data and CT images, and providing for quality assurance. This advanced registry and its rapid accumulation of data and images allowed continual assessment and updating of the regimen of screening as advances in knowledge and new technology emerged. For example, in the initial ELCAP study, introduction of helical CT scanners had allowed imaging of the entire lungs in a single breath, but the images were obtained in 10 mm increments resulting in about 30 images per person. Today, images are obtained in submillimeter slice thickness, resulting in around 700 images per person, which are viewed on high-resolution monitors. The regimen provides the imaging acquisition parameters, imaging interpretation, definition of positive result, and the recommendations for further workup, which now include identification of emphysema and coronary artery calcifications. Continual updating is critical to maximize the benefit of screening and to minimize potential harms. Insights were gained about the natural history of lung cancers, identification and management of nodule subtypes, increased understanding of nodule imaging and pathologic features, and measurement variability inherent in CT scanners. The registry also provides the foundation for assessment of new statistical techniques, including artificial intelligence, and integration of effective genomic and blood-based biomarkers, as they are developed.

Clinicopathologic Characteristics and Prognosis of Patients With Non–Small Cell Lung Cancer Who Undergo Pulmonary Segmentectomy

This study retrospectively investigated the clinical characteristics and prognosis of the non–small cell lung cancer (NSCLC) patients who underwent segmentectomy as either intentional or passive limited surgery. The subjects included in this study comprised 72 patients who underwent segmentectomy at our hospital. There were 23 patients who underwent intentional segmentectomy. The histologic type was adenocarcinoma in all of these patients. Regarding the tumor size, 9 tumors were 1 cm or less in diameter, 13 were 1.1 to 2 cm, and 1 was 2.5 cm. All patients who underwent intentional segmentectomy were alive without any recurrence as of the last follow-up examination. A passive segmentectomy was performed for 49 patients. The reasons for passive segmentectomy were due to the presence of metachronous multiple lung cancer in 14 patients, synchronous multiple lung cancer in 9 patients, age above 80 years in 12 patients, reduced pulmonary function in 8 patients, and moderate to severe cardiovascular disease in 4 patients; another 2 patients were receiving treatment for another primary cancer. The 5-year survival rate of the patients who underwent passive segmentectomy was 69.8%. There was no postoperative mortality in either of the groups. This study showed that all of the patients who underwent intentional segmentectomy were alive without any recurrence, thus suggesting that the procedure is associated with sufficient oncologic efficacy, along with preservation of the lung function. The passive segmentectomy was a feasible procedure and was an alternative procedure with an acceptable overall survival rate in high-risk patients with underlying medical comorbidities.

Effectiveness of intraoperative bimanual palpation in metastatic tumors of lung

Background

In this study, we aimed to compare effectiveness of thoracic computed tomography versus intraoperative bimanual palpation in the detection of number of nodules in patients undergoing thoracotomy.

Methods

Between January 2011 and January 2019, a total of 157 patients (63 males, 94 females; mean age: 46.6±11.2 years; range, 13 to 77 years) who underwent pulmonary metastasectomy in our institution were retrospectively analyzed. Metastatic nodules evaluated using thoracic computed tomography were compared with nodules detected by intraoperative palpation.

Results

A total of 226 muscle-sparing thoracotomy was performed in 157 patients. The time between the preoperative thoracic computed tomography and operation ranged from 3 to 24 days. Metastasectomy with muscle-sparing thoracotomy was performed in 41 (26%) patients two times, in eight (5%) patients three times, and in four (2.5%) patients four times due to bilateral lung metastasis or re-metastasectomy. The thoracic computed tomography could detect 476 metastatic nodules, while 1,218 nodules were palpated and resected intraoperatively. Of these nodules, 920 were pathologically evaluated as metastatic.

Conclusion

Our study results showed that the number of nodules reported as pathologically malignant after resection was 1.9 times higher than those reported by thoracic computed tomography. This finding indicates that intraoperative bimanual examination significantly increases the possibility of complete resection. This situation raises the need for more caution for the thoracoscopic metastasectomy procedure in which there is no possibility of intraoperative bimanual palpation.

Comparison of cyanoacrylate and hookwire for localizing small pulmonary nodules: A propensity-matched cohort study

BACKGROUND

Localizing small pulmonary nodules (SPNs) is a challenge during thoracoscopic resection, but preoperative computed tomography (CT)-guided localization using either cyanoacrylate or hookwire can be helpful. This study compared the safety, efficiency, and operability of the two techniques.

METHODS

From September 2013 to November 2018, 269 patients (269 SPNs) who underwent preoperative CT-guided SPN localization were enrolled. A propensity-matched analysis, incorporating 13 variables, was performed to control potential selection bias.

RESULTS

All the patients were divided into two groups: CT-guided cyanoacrylate localization group (Group C, n = 149) and CT-guided hookwire localization group (Group H, n = 120). Eighty-six patients were propensity-matched in each group. All SPNs were successfully removed thoracoscopically, and no conversion was required. Localization-related complications in the two groups were similar, including intrapulmonary focal hemorrhage (p = 0.823), pneumothorax (p = 1.000), or hemoptysis (p = 0.121). For pain assessment and management, the cyanoacrylate localization saw a lower pain score (p < 0.001) and less morphine use (p < 0.001). In Group H, the localization took a significantly longer time (p < 0.001). Covering only the patients in Group C, the sub-analysis found that cyanoacrylate localization on the day before surgery did not compromise the accuracy of intraoperative targeting or increase the incidence of complications, compared with the localization on the day of surgery (all p > 0.05).

CONCLUSION

Compared to hookwire localization, CT-guided cyanoacrylate localization decreased pain and morphine use and allowed flexible surgical schedules, suggestive of its preferability for the resection of SPNs.

Implementation planning for lung cancer screening in China

Lung cancer is the leading cause of cancer-related deaths in China, with over 690 000 lung cancer deaths estimated in 2018. The mortality has increased about five-fold from the mid-1970s to the 2000s. Lung cancer low-dose computerized tomography (LDCT) screening in smokers was shown to improve survival in the US National Lung Screening Trial, and more recently in the European NELSON trial. However, although the predominant risk factor, smoking contributes to a lower fraction of lung cancers in China than in the UK and USA. Therefore, it is necessary to establish Chinese-specific screening strategies. There have been 23 associated programmes completed or still ongoing in China since the 1980s, mainly after 2000; and one has recently been planned. Generally, their entry criteria are not smoking-stringent. Most of the Chinese programmes have reported preliminary results only, which demonstrated a different high-risk subpopulation of lung cancer in China. Evidence concerning LDCT screening implementation is based on results of randomized controlled trials outside China. LDCT screening programmes combining tobacco control would produce more benefits. Population recruitment (e.g. risk-based selection), screening protocol, nodule management and cost-effectiveness are discussed in detail. In China, the high-risk subpopulation eligible for lung cancer screening has not as yet been confirmed, as all the risk parameters have not as yet been determined. Although evidence on best practice for implementation of lung cancer screening has been accumulating in other countries, further research in China is urgently required, as China is now facing a lung cancer epidemic.

CT-guided percutaneous core needle biopsy of pulmonary nodules smaller than 2 cm: technical aspects and factors influencing accuracy

OBJECTIVE

To evaluate the diagnostic accuracy of CT-guided percutaneous core needle biopsy (CT-CNB) of pulmonary nodules ≤ 2 cm, as well as to identify factors influencing the accuracy of the procedure and its morbidity.

METHODS

This was a retrospective, single-center study of 170 consecutive patients undergoing CT-CNB of small pulmonary nodules (of ≤ 2 cm) between January of 2010 and August of 2015.

RESULTS

A total of 156 CT-CNBs yielded a definitive diagnosis, the overall diagnostic accuracy being 92.3%. Larger lesions were associated with a higher overall accuracy (OR = 1.30; p = 0.007). Parenchymal hemorrhage occurring during the procedure led to lower accuracy rates (OR = 0.13; p = 0.022). Pneumothorax was the most common complication. A pleura-to-lesion distance &gt; 3 cm was identified as a risk factor for pneumothorax (OR = 16.94), whereas performing a blood patch after biopsy was a protective factor for pneumothorax (OR = 0.18).

CONCLUSIONS

Small nodules (of < 2 cm) represent a technical challenge for diagnosis. CT-CNB is an excellent diagnostic tool, its accuracy being high.

Preoperative risk assessment with computed tomography in patients undergoing lung cancer surgery

Background

Although whole lung computed tomography (CT) is included in the routine workup before lung cancer surgery, it is not utilized to assess the preoperative pulmonary function.

Methods

Two hundred ninety patients (development cohort) who underwent lung lobectomy for cancer in our institute and another 100 patients (validation cohort) who subsequently underwent the same operation in a referral hospital were included. The total lung volume (TLV) and emphysematous lung volume (ELV) were obtained by quantitative CT.

Results

The TLV was higher in patients with a smoking history than in those without. The ELV to the TLV was higher in elderly patients than in younger patients. The regression equation for forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV₁) were developed using CT-derived variables, together with sex, age, height, and smoking habit, by a multiple regression analysis in the development cohort. The regression equation-based FVC and FEV₁ were significantly correlated with the actual FVC and FEV₁ in the development cohort, as well as in the validation cohort. The predicted postoperative FEV₁ (ppo%FEV₁) calculated based on the regression equation was also correlated with the postoperative FEV₁ value obtained by the conventional method (R=0.53), and the regression equation-based ppo%FEV₁ was a significant predictor of postoperative cardiopulmonary complications (P=0.02).

Conclusions

Whole lung CT can be used to assess the preoperative pulmonary function in patients undergoing lobectomy for cancer. This method may be helpful in preoperative risk assessment, particularly in patients who have difficulty in implementation of spirometry.

Long-term results after surgical treatment of the dominant lung adenocarcinoma associated with ground-glass opacities

Background

To evaluate the effect of first-time and eventual reiterative surgery on overall survival (OS) and disease-free survival (DFS) in Caucasian patients affected by an invasive adenocarcinoma (ADC) with at least another ground-glass opacity (GGO).

Methods

We analysed 47 patients operated on for lung ADC, identified as main cancer (MC), with at least one synchronous GGO, from January 2003 to March 2017. Characteristics associated with the evolution of GGOs were investigated with logistic regression and overall and DFS were evaluated with Kaplan-Meier method.

Results

Forty-two (89%) patients received an anatomic resection of the MC, 5 patients were treated by a single or multiple wedge resections. In total, 9 (19.1%) patients had all the lesions resected undergoing simultaneous resection of ipsilateral GGOs at first surgery while the remaining 38 (80.9%) patients still had at least one GGO that was followed up by serial CT scan. At the median follow-up of 41 months, GGO evolved in 16 (42.1%) patients. The presence of solid component at the initial CT scan was the only risk factor for evolution of the GGO. Thirteen patients underwent surgical resection showing an invasive ADC in 9 patients, MIA in 3 and AIS in 1. New GGOs developed in 7 (14.9%) patients, in which three underwent surgery showing the presence of solid ADC, MIA and AAH. OS rate at 5 years was 97.4%. DFS at 3 years was 82% and was significantly influenced by the stage of MC.

Conclusions

Patients affected by an invasive ADC with at least another GGO nodule enjoy good OS and DFS with a surgical reiterative approach. Part-solid GGO is associated with GGO progression requiring treatment, but OS is not influenced by the new onset or evolution of GGOs. DFS is affected by the stage of the MC which dictates the treatment strategy.

Image guidance in proton therapy for lung cancer

Proton therapy is a promising but challenging treatment modality for the management of lung cancer. The technical challenges are due to respiratory motion, low dose tolerance of adjacent normal tissue and tissue density heterogeneity. Different imaging modalities are applied at various steps of lung proton therapy to provide information on target definition, target motion, proton range, patient setup and treatment outcome assessment. Imaging data is used to guide treatment design, treatment delivery, and treatment adaptation to ensure the treatment goal is achieved. This review article will summarize and compare various imaging techniques that can be used in every step of lung proton therapy to address these challenges.

Risk factors for pulmonary nodules in north China: A prospective cohort study

OBJECTIVES

Pulmonary nodules have become common incidental findings with the widespread use of computed tomography (CT) technology. Such nodules have the potential to become early lung cancer lesions, so understanding more about factors that may be associated with them is important.

MATERIALS AND METHODS

The present work was based on a large prospective cohort comprising 32,438 participants in Hebei Province (China) between January 2014 and March 2016. Participants aged 40-75 years completed a questionnaire, underwent low-dose CT (LDCT), and were followed up to March 2017. Grouped by the results of LDCT, normal participants and those with pulmonary nodules were included in the data analysis.

RESULTS

In total 7752 subjects were included in this study, of whom 2040 (26.32%) were pulmonary nodule patients. Older age, current smoking status (hazard ratio (HR) = 1.43, 95% confidence interval (95%CI): 1.21, 1.68), exposure to second-hand smoke (SHS) at work (HR = 1.17, 95%CI: 1.01, 1.35), dust exposure (HR = 1.49, 95%CI: 1.06, 2.11), history of lung disease (HR = 1.44, 95%CI: 1.16, 1.77), and family history of cancer (HR = 1.28, 95%CI: 1.12, 1.48) were associated with pulmonary nodules. However, consumption of vegetables (HR = 0.82, 95%CI: 0.68, 0.99), tea (HR = 0.88, 95%CI: 0.78, 0.99) and legumes reduced the risk. Approximately 10.09% and 8.58% of pulmonary nodule incidences were attributed to tobacco smoking and low fruit intake, respectively. An estimated 6.36% and 3.88% of patients with pulmonary nodules attributable to family history of cancer and history of lung disease were detected.

CONCLUSION

The results of this study suggest that age, smoking, SHS, dietary factors, occupational exposures, history of disease and family history of cancer may affect the incidence of pulmonary nodules.

Three-dimensional Navigation for Thoracoscopic Sublobar Resection Using a Novel Wireless Marking System

We developed a novel localization technique for small intrapulmonary lesions using radiofrequency identification (RFID) technology. Micro-RFID markers with nickel-titanium coils were designed to be placed from subsegmental bronchi to the peripheral parenchyma. In this preclinical study, thoracoscopic subsegmentectomy of a canine pseudotumor model was performed to demonstrate the feasibility and three-dimensional positional accuracy of the system. To recover subcentimeter pseudotumors, markers were bronchoscopically placed to determine the resection line: (1) next to the pseudotumor; (2) in the responsible subsegmental bronchi as the central margin; and (3) on the intersubsegmental plane as the lateral margin. Specific marker positions were located by wireless communication using a wand-shaped probe with a 30-mm communication range, with the distance to the marker indicated by gradual changes in sound pitch. Thirty-four markers were placed for 10 pseudotumors (14.6 mm from the pleura) in 10 canines. Three markers were placed at a mean distance of 5.5 mm from the pseudotumors, and 11 central and 20 lateral markers were placed at mean distances of 17.2 and 20.7 mm from the pseudotumors, respectively. Central markers (20.5 mm from the pleura) were detected within 16.0 seconds in 2.9-mm-diameter bronchi. All resection stumps were within 5.4 mm (range 2-8 mm) from each marker, and pseudotumors were removed with adequate surgical margins toward the central (11.5 mm; range 7-16 mm) and lateral (12.4 mm; range 9-17 mm) directions. RFID wireless markers provided precise three-dimensional positional information and are a potential viable alternative to conventional markers.

Robust transcriptional signatures for low-input RNA samples based on relative expression orderings

Background

It is often difficult to obtain sufficient quantity of RNA molecules for gene expression profiling under many practical situations. Amplification from low-input samples may induce artificial signals.

Results

We compared the expression measurements of low-input mRNA samples, from 25 pg to 1000 pg mRNA, which were amplified and profiled by Smart-seq, DP-seq and CEL-seq techniques using the Illumina HiSeq 2000 platform, with those of the paired high-input (50 ng) mRNA samples. Even with 1000 pg mRNA input, we found that thousands of genes had at least 2 folds-change of expression levels in the low-input samples compared with the corresponding paired high-input samples. Consequently, a transcriptional signature based on quantitative expression values and determined from high-input RNA samples cannot be applied to low-input samples, and vice versa. In contrast, the within-sample relative expression orderings (REOs) of approximately 90% of all the gene pairs in the high-input samples were maintained in the paired low-input samples with 1000 pg input mRNA molecules. Similar results were observed in the low-input total RNA samples amplified and profiled by the Whole-Genome DASL technique using the Illumina HumanRef-8 v3.0 platform. As a proof of principle, we developed REOs-based signatures from high-input RNA samples for discriminating cancer tissues and showed that they can be robustly applied to low-input RNA samples.

Conclusions

REOs-based signatures determined from the high-input RNA samples can be robustly applied to samples profiled with the low-input RNA samples, as low as the 1000 pg and 250 pg input samples but no longer stable in samples with less than 250 pg RNA input to a certain degree.

Electronic supplementary material

The online version of this article (10.1186/s12864-017-4280-7) contains supplementary material, which is available to authorized users.

Management of indeterminate pulmonary nodules (<1 cm) newly detected during the follow-up of nasopharyngeal carcinoma patients

AIM

To investigate the management for the indeterminate pulmonary nodules newly detected during the follow-up for nasopharyngeal carcinoma (NPC) patients.

METHODS

Indeterminate pulmonary lesions were identified by searching medical records of NPC patients, who were followed-up with thoracic CT between April 2008 and February 2014. Indeterminate pulmonary nodules were defined as opacities that may be solitary or multiple, which were <1 cm in size and not calcified. Nodules which were followed-up for at least two years, were included into analysis. The nodules with growth were considered as metastatic lesions and those which remained stable or regressed were defined as benign. The relations between the risk of the nodules to develop into metastatic lesions and clinical features and characteristics of nodules were analyzed.

RESULTS

Through a median follow-up of 50 months, the majority (81 of 102, 79.4%) had no change in the size of nodules. The nodules have regressed in 11 patients. There were 10 (9.8%) cases with progression at the follow-up. The 10 patients were considered to have lung metastases, for whom continuous increases of lesions were revealed. The volume doubling time of the increasing nodules ranged from 34 to 105 days. The nodules emerging within two years after primary therapies were more likely to develop into metastatic lesions (P = 0.043).

CONCLUSION

Ten percent of the indeterminate pulmonary nodules represent metastatic diseases. A short-interval follow-up is recommended and if the nodules remain stable after six months follow-up, it may be proper to prolong the interval of follow-up.

[Predictive factors of complications during CT-guided transthoracic biopsy]

INTRODUCTION

CT-guided transthoracic core-needle biopsy (TTNB) is frequently used for the diagnosis of lung nodules. The aim of this study is to describe TTNBs' complications and to investigate predictive factors of complications.

METHODS

All consecutive TTNBs performed in three centers between 2006 and 2012 were included. Binary logistic regression was used for multivariate analysis.

RESULTS

Overall, 970 TTNBs were performed in 929 patients. The complication rate was 34% (life-threatening complication in 6%). The most frequent complications were pneumothorax (29% included 4% which required chest-tube) and hemoptysis (5%). The mortality rate was 0.1% (n=1). In multivariate analysis, predictive factor for a complication was small target size (AOR=0.984; 95% CI [0.976-0.992]; P<0.001). This predictive factor was also found for occurrence of life-threatening complication (AOR=0.982; [0.965-0.999]; P=0.037), of pneumothorax (AOR=0.987; [0.978-0.995]; P=0.002) and of hemoptysis (AOR=0.973; [0.951-0.997]; P=0.024).

CONCLUSION

One complication occurred in one-third of TTNBs. The proportion of life-threatening complication was 6%. A small lesion size was predictive of complication occurrence.

Non-specific benign pathological results on transthoracic core-needle biopsy: how to differentiate false-negatives?

OBJECTIVES

To determine the negative predictive value (NPV) of non-specific benign results from cone-beam CT (CBCT)-guided transthoracic core-needle biopsy (TTNB) and identify predicting factors for false-negative for malignancies.

METHODS

From January 2009-December 2011, 1,108 consecutive patients with 1,116 lung lesions underwent CBCT-guided TTNB using an 18-gauge coaxial cutting needle. Among them, 226 patients with 226 TTNBs, initially diagnosed as non-specific benign, were included in this study. The medical charts, radiological or pathological follow-ups were reviewed to classify false-negative and true-negative results and to identify which variables were associated with false-negatives.

RESULTS

Of 226 lesions, 24 (10.6%) were finally confirmed as malignancies and 202 (89.4%) as benign, of which the NPV was 89.4% (202/226). Multivariate analysis revealed that part-solid nodule (PSN) (odds ratio (OR), 3.95; P = 0.022), a biopsy result of 'granulomatous inflammation' (OR, 0.04; P = 0.022), and exact location of needle tip within targets (OR, 0.37; P = 0.045) were significantly associated with false-negatives among initial non-specific benign biopsy results.

CONCLUSION

The NPV of the non-specific benign biopsy was 89.4%. PSN was a significant positive indicator, but a biopsy result of 'granulomatous inflammation' and exact location of needle tip within targets were significant negative indicators for false-negatives.

KEY POINTS

• The negative predictive value of the non-specific benign biopsy was 89.4%. • A part-solid nodule is a significant predictor for false-negative biopsy (OR = 3.95). • Pathological diagnosis of granulomatous inflammation is a robust indicator for 'true-negatives'. • Identifying needle tip within target lesions is a significant predictor for 'true-negatives'.

The imaging of small pulmonary nodules

Lung cancer is the leading cause of cancer death worldwide. The major goal in lung cancer research is the improvement of long-term survival. Pulmonary nodules have high clinical importance, they may not only prove to be an early manifestation of lung cancer, but decide to choose the right therapy. This review will introduce the development and current situation of several imaging examination methods: computed tomography (CT), positron emission tomography/computed tomography (PET/CT), endobronchial ultrasound (EBUS).

Recent developments in video-assisted thoracoscopic surgery for pulmonary nodule management

In the modern era when screening and early surveillance of pulmonary nodules is increasing in importance, the management of the pulmonary nodule represents a different challenge to thoracic surgeons. The difficulty lies in the merging of sound surgical and oncological principles with more minimally invasive and appropriate lung sparing surgery. Furthermore, the intra-operative identification and surgical management of small and sometimes multi-focal pulmonary lesions remain challenging. There have been many developments and innovations in the field of video-assisted thoracoscopic surgery (VATS) to cater for the demands from increasing incidence of pulmonary nodules with associated paradigm shift in their surgical management. Recently, uniportal VATS and non-intubated VATS represent an even less invasive alternative to the conventional multiport VATS. The emergence of image guided VATS, hybrid operating theatre and fluorescence thoracoscopy have all contributed to improved precision of VATS lung resection, and are becoming important adjuncts to lung sparing surgery. In this chapter, some of these recent developments in VATS with emphasize on their importance in surgical management of the pulmonary nodule will be discussed.

Image-guided video assisted thoracoscopic surgery (iVATS) - phase I-II clinical trial

Purpose

To facilitate localization and resection of small lung nodules, we developed a prospective clinical trial (ClinicalTrials.govnumber NCT01847209) for a novel surgical approach which combines placement of fiducials using intra‐operative C‐arm computed tomography (CT) guidance with standard thoracoscopic resection technique using image‐guided video‐assisted thoracoscopic surgery (iVATS).

Methods

Pretrial training was performed in a porcine model using C‐arm CT and needle guidance software. Methodology and workflow for iVATS was developed, and a multi‐modality team was trained. A prospective phase I‐II clinical trial was initiated with the goal of recruiting eligible patients with small peripheral pulmonary nodules. Intra‐operative C‐arm CT scan was utilized for guidance of percutaneous marking with two T‐bars (Kimberly‐Clark, Roswell, GA) followed by VATS resection of the tumor.

Results

Twenty‐five patients were enrolled; 23 underwent iVATS, one withdrew, and one lesion resolved. Size of lesions were: 0.6–1.8 cm, mean = 1.3 ± 0.38 cm.. All 23 patients underwent complete resection of their lesions. CT imaging of the resected specimens confirmed the removal of the T‐bars and the nodule. Average and total procedure radiation dose was in the acceptable low range (median = 1501 μGy*m², range 665–16,326). There were no deaths, and all patients were discharged from the hospital (median length of stay = 4 days, range 2–12). Three patients had postoperative complications: one prolonged air‐leak, one pneumonia, and one ileus.

Conclusions

A successful and safe step‐wise process has been established for iVATS, combining intra‐operative C‐arm CT scanning and thoracoscopic surgery in a hybrid operating room. J. Surg. Oncol. 2015 111:18–25. © 2015 The Authors. Journal of Surgical Oncology Published by Wiley Periodicals, Inc.

Effect of the high-pitch mode in dual-source computed tomography on the accuracy of three-dimensional volumetry of solid pulmonary nodules: a phantom study

Objective

To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules.

Materials and Methods

A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated.

Results

In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 ± 0.9%, and 1.7 ± 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 ± 7.4%) was significantly greater (p < 0.01) than that in the CPM (18.4 ± 5.3%), with an IVV of 13.1 ± 6.6%. However, the IVVs were in an acceptable range (< 25%), regardless of nodule size.

Conclusion

The accuracy of 3D volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule.

Lung cancer associated with cystic airspaces

OBJECTIVE

This study aimed to define computed tomographic morphologic features of lung cancer associated with cystic airspaces, their modifications in serial computed tomographic scans, and 18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography uptake.

METHODS

Computed tomographic scans and 18F-FDG positron emission tomography in 24 patients with lung cancer (17 adenocarcinomas, 7 squamous cell carcinomas, 12 stage I and 12 stage II to IV) associated with cystic airspaces were reviewed.

RESULTS

Mean diameter of airspace was initially 17.6 mm (range, 5-30 mm), and 4 morphologic patterns were recognized: solid nodule protruding externally (type I, n = 5) or internally (type II, n = 4) from the cyst wall; circumferential thickening of the cyst wall (type III, n = 8); and tissue intermixed within clusters of cysts (type IV, n = 7). With tumor growth, airspace size decreased in 9, increased in 6, and was unchanged in 9 cases. Five cases evolved from type III to type I, and 5 lesions became completely solid. 18F-fluoro-2-deoxy-D-glucose uptake was initially absent to mild in 7 and moderate to marked in 14 lesions.

CONCLUSIONS

Progressive wall thickening or appearance/increase of a nodule inside or outside a cystic airspace should raise suspicion of lung cancer irrespective of FDG uptake.

The role of octreotate scan in discrimination of solitary pulmonary nodule

Solitary pulmonary nodule (SPN) is one of the most controversial clinical findings in patients. The aim of this study is to use (99m)Tc-ethylenediamine diacetic acid/hydrazine nicotinamide (HYNIC)-TATE scan technique to evaluate nodules. From 2008 to 2010, 21 patients with SPN underwent (99m)Tc-HYNIC-TATE scan after the initial assessment with high-resolution computed tomography and then accurate histopathologic diagnosis was established by trans-thoracic needle biopsy, Video Assisted Thoracic Surgery and thoracotomy. After demographic evaluations, specificity and sensitivity of this method was studied. A total of 21 patients were included in our study, of which 12 patients were male and 9 were female. Their mean age was 45 ± 14.3 years. About 43% of the patients were symptom-free and in patients with pulmonary complaints, the most prevalent symptom was cough. Final histopathology tests and clinical follow-up proved that 14 cases (67%) were benign and 7 (33%) were malignant. The diagnostic technique used in our study had no false negative and there were only 3 cases of false positive. Sensitivity and specificity of this method are 100% and 79%, respectively and the diagnostic accuracy is 86%. (99m)Tc-HYNIC-TATE scan can be helpful in evaluating patients with SPN and to reach a sensible decision on the method of treatment.

Initial LDCT appearance of incident lung cancers in the ITALUNG trial

OBJECTIVES

To characterize early features of lung cancers detected with low-dose computed tomography (LDCT) screening.

MATERIALS AND METHODS

Two radiologists reviewed prior LDCTs in 20 incident cancers diagnosed at annual repeat screening rounds and 83 benign nodules observed in the ITALUNG trial.

RESULTS

No abnormality was observed in 3 cancers. Focal abnormalities in prior LDCT were identified in 17(85%) cancers (14 adenocarcinomas; 14 stage I). Initial abnormalities were intra-pulmonary in 10, subpleural in 4 and perifissural in 3. Average mean diameter was 9mm (range 4.5-18mm). Nine exhibited solid, 4 part-solid and 4 non-solid density. The margins were smooth and regular in 5 cases, lobulated in 6, irregular with spiculations in 3 and blurred in 3. Ten (59%) initial focal abnormalities had a round or oval nodular shape, but 7(41%) had a non-nodular complex (n=5) or "stripe-like" (n=2) shape. Bronchus sign was observed in 3 cases and association with cystic airspace in 2 cases. Non-solid density, complex or "stripe-like" shape, bronchus sign and association with cystic airspace had a specificity higher than 90%, but positive predictive value of every feature of incident lung cancers was low (range 10.4-50%).

CONCLUSIONS

The vast majority of cancers diagnosed at annual repeat show corresponding focal lung abnormalities in prior LDCTs. Perifissural location and non-nodular shape do not exclude the possibility of early lung cancer. Since specificity of the early features of incident lung cancer is incomplete and their positive predictive value is low, all focal pulmonary abnormalities detected in screened subjects should be re-evaluated in subsequent LDCTs.

The assessment of the role of baseline low-dose CT scan in patients at high risk of lung cancer

BACKGROUND

Despite the progress in contemporary medicine comprising diagnostic and therapeutic methods, lung cancer is still one of the biggest health concerns in many countries of the world. The main purpose of the study was to evaluate the detection rate of pulmonary nodules and lung cancer in the initial, helical low-dose CT of the chest as well as the analysis of the relationship between the size and the histopathological character of the detected nodules.

MATERIAL/METHODS

We retrospectively evaluated 1999 initial, consecutive results of the CT examinations performed within the framework of early lung cancer detection program initiated in Szczecin. The project enrolled persons of both sexes, aged 55-65 years, with at least 20 pack-years of cigarette smoking or current smokers. The analysis included assessment of the number of positive results and the evaluation of the detected nodules in relationship to their size. All of the nodules were classified into I of VI groups and subsequently compared with histopathological type of the neoplastic and nonneoplastic pulmonary lesions.

RESULTS

Pulmonary nodules were detected in 921 (46%) subjects. What is more, malignant lesions as well as lung cancer were significantly, more frequently discovered in the group of asymptomatic nodules of the largest dimension exceeding 15 mm.

CONCLUSIONS

The initial, low-dose helical CT of the lungs performed in high risk individuals enables detection of appreciable number of indeterminate pulmonary nodules. In most of the asymptomatic patients with histopathologically proven pulmonary nodules greater than 15 mm, the mentioned lesions are malignant, what warrants further, intensified diagnostics.

Size of solitary pulmonary nodule was the risk factor of malignancy

OBJECTIVE

The purpose of this study was to analyze the role of the sizes of solitary pulmonary nodules (SPNs) in predicting their potential malignancies.

METHODS

A total of 379 patients with pathologically confirmed SPNs were enrolled in this study. They were divided into three groups based on the SPN sizes: ≤10, 11-20, and >20 mm. The computed tomography (CT) findings of these SPNs were analyzed in these three groups to identify the malignant and benign SPNs. The risk factors were analyzed using binary logistic regression analysis.

RESULTS

Of these 379 patients, 120 had benign SPNs and 259 had malignant SPNs. In the ≤10 mm SPN group, air cavity density was the risk factor for malignancy, with the sensitivity, specificity, and accuracy being 77.8%, 75.0%, and 76.3%. In the 11-20 mm SPN group, age, glitches and vascular aggregation were the risk factors for malignancy, with the sensitivity, specificity, and accuracy being 91.3%, 56.9%, and 81.5%. In the >20 mm SPN group, age, lobulation, and vascular aggregation were the risk factors for malignancy, with the sensitivity, specificity, and accuracy being 88.6%, 57.1%, and 79.1%.

CONCLUSIONS

According to CT findings of SPNs, age, glitches, lobulation, vascular aggregation, and air cavity density are the risk factors of malignancy, whereas calcification and satellite lesions are the protective factors. During the course of development from small to large nodules, air cavity density could be firstly detected in early stages, followed by glitches and vascular aggregation. Lobulation is associated with relatively large lesions.

Decreased levels of circulating sex hormones as a biomarker of lung cancer in male patients with solitary pulmonary nodules

BACKGROUND

An early differentiation of malignant from benign solitary pulmonary nodules (SPNs) is essential for management and prognosis of lung cancer.

OBJECTIVES

Here we investigated whether measurement of circulating sex hormones could be useful for an early detection of malignancy among patients with SPNs.

METHODS

We recruited 47 patients with malignant SPNs 45 patients with benign SPNs, and 32 healthy persons. Testosterone, estradiol, and progesterone were measured. Carcinoembryonic antigen (CEA) as well as TNF-α, IL-1 and IL-6 were also measured.

RESULTS

We found that sex hormones were decreased significantly in patients with malignant SPNs, as compared to patients with benign SPNs and healthy controls (P<0.05). Sex hormones levels showed a trend to decline in patients with benign SPNs as compared to normal controls, but the difference was not statistically significant (P>0.05). CEA levels were only abnormally elevated in eight patients with lung adenocarcinoma. The inflammatory cytokines were remarkably higher in both patients than in normal controls. However, there was no statistical difference in these cytokines among patients.

CONCLUSIONS

The reduced sex hormones levels seemed to be uniquely associated with lung cancer. Therefore, measurement of sex hormones may have clinical potential in the diagnosis of malignancy in patients with SPNs.

Resource use and guideline concordance in evaluation of pulmonary nodules for cancer: too much and too little care

IMPORTANCE

Pulmonary nodules are common, and more will be found with implementation of lung cancer screening. How potentially malignant pulmonary nodules are evaluated may affect patient outcomes, health care costs, and effectiveness of lung cancer screening programs. Guidelines for evaluating pulmonary nodules for cancer exist, but little is known about how nodules are evaluated in the usual care setting.

OBJECTIVE

To characterize nodule evaluation and concordance with guidelines.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study was conducted including detailed review of medical records from pulmonary nodule detection through evaluation completion, cancer diagnosis, or study end (December 31, 2012). The participants included 300 adults with pulmonary nodules from 15 Veterans Affairs hospitals.

MAIN OUTCOMES AND MEASURES

Resources used for evaluation at any Veterans Affairs facility and guideline-concordant evaluation served as the main outcomes.

RESULTS

Twenty-seven of 300 patients (9.0%) with pulmonary nodules ultimately received a diagnosis of lung cancer: 1 of 57 (1.8%) with a nodule of 4 mm or less, 4 of 134 (3.0%) with a nodule of 5 to 8 mm, and 22 of 109 (20.2%) with a nodule larger than 8 mm. Nodule evaluation entailed 1044 imaging studies, 147 consultations, 76 biopsies, 13 resections, and 21 hospitalizations. Radiographic surveillance (n = 277) lasted a median of 13 months but ranged from less than 0.5 months to 8.5 years. Forty-six patients underwent invasive procedures (range per patient, 1-4): 41.3% (19 patients) did not have cancer and 17.4% (8) experienced complications, including 1 death. Notably, 15 of the 300 (5.0%) received no purposeful evaluation and had no obvious reason for deferral, seemingly "falling through the cracks." Among 197 patients with a nodule detected after release of the Fleischner Society guidelines, 44.7% received care inconsistent with guidelines (17.8% overevaluation, 26.9% underevaluation). In multivariable analyses, the strongest predictor of guideline-inconsistent care was inappropriate radiologist recommendations (overevaluation relative risk, 4.6 [95% CI, 2.3-9.2]; underevaluation, 4.3 [2.7-6.8]). Other systems factors associated with underevaluation included receiving care at more than 1 facility (2.0 [1.5-2.7]) and nodule detection during an inpatient or preoperative visit (1.6 [1.1-2.5]).

CONCLUSIONS AND RELEVANCE

Pulmonary nodule evaluation is often inconsistent with guidelines, including cases with no workup and others with prolonged surveillance or unneeded procedures that may cause harm. Systems to improve quality (eg, aligning radiologist recommendations with guidelines and facilitating communication across providers) are needed before lung cancer screening is widely implemented.

The Lung Reporting and Data System (LU-RADS): A Proposal for Computed Tomography Screening

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 <5 mm, perifissural, or long-term stable nodules that require no further workup before the next routine screening CT. Category 3 scans contain indeterminate nodules and require CT follow up with the interval dependent on nodule size (small [5-9 mm] or large [≥10 mm] and possibly transient). Category 4 scans are suspicious and are subdivided into 4A, low risk of malignancy; 4B, likely low-grade adenocarcinoma; and 4C, likely malignant. The 4B and 4C nodules have a high likelihood of neoplasm simply based on screening CT features, even if positron emission tomography, needle biopsy, and/or bronchoscopy are negative. Category 5 nodules demonstrate frankly malignant behavior on screening CT, and category 6 scans contain tissue-proven malignancies.

Evaluation of undiagnosed solitary lung nodules according to the probability of malignancy in the American College of Chest Physicians (ACCP) evidence-based clinical practice guidelines

Background

This study retrospectively investigated the clinical significance of undiagnosed solitary lung nodules removed by surgical resection.

Patients and methods

We retrospectively collected data on the age, smoking, cancer history, nodule size, location and spiculation of 241 patients who had nodules measuring 7 mm to 30 mm and a final diagnosis established by histopathology. We compared the final diagnosis of each patient with the probability of malignancy (POM) which was proposed by the American College of Chest Physicians (ACCP) guidelines.

Results

Of the 241 patients, 203 patients were diagnosed to have a malignant lung tumor, while 38 patients were diagnosed with benign disease. There were significant differences in the patients with malignant and benign disease in terms of their age, smoking history, nodule size and spiculation. The mean value and the standard deviation of the POM in patients with malignant tumors were 51.7 + 26.1%, and that of patients with benign lesions was 34.6 + 26.7%. The area under the receiver operating characteristic (ROC) curve (AUC) was 0.67. The best cut-off value provided from the ROC curve was 22.6. When the cut-off value was set at 22.6, the sensitivity was 83%, specificity 52%, positive predictive value 90%, negative predictive value 36% and accuracy 77%, respectively.

Conclusions

The clinical prediction model proposed in the ACCP guidelines showed unsatisfactory results in terms of the differential diagnosis between malignant disease and benign disease of solitary lung nodules in our study, because the specificity, negative predictive value and AUC were relatively low.

Gene expression ratio test distinguishes normal lung from lung tumors in solid tissue and FNA biopsies

Lung cancer is the leading cause of cancer-related deaths worldwide. Prognosis and survival are dependent on cell type, early detection, and surgical treatment. Hence, optimal screening strategies and new therapies are urgently required. Although surveillance with low-dose computed tomography can reduce lung cancer mortality by 20%, the number of false-positive detections is significant. Tissue diagnosis aids in the identification of benign nodules, reducing the number of false positive detections. To determine whether molecular testing of fine-needle aspirations (FNAs) can reduce false-positive detections, we developed a gene expression-based test that distinguishes normal from cancerous lung tissues. The test first was applied to published microarray data, showing overall sensitivity and specificity values of 95% (95% CI, 90%-98%) and 100% (95% CI, 40%-100%), respectively. Subsequently, it was validated on 30 solid and ex vivo FNA lung cancer tumor samples and matched normal lung specimens using real-time PCR. The validation test was 93% (95% CI, 78%-99%) sensitive and 100% (95% CI, 88%-100%) specific for the detection of tumor versus normal lung on solid samples, whereas FNA specimens yielded a sensitivity of 91% (95% CI, 72%-99%) and a specificity of 94% (95% CI, 70%-100%). This study supports the hypothesis that the gene-ratio approach reliably distinguishes normal lung from cancerous tissues in FNA samples and can be optimized to diagnose benign nodules.

A novel approach for lung nodules segmentation in chest CT using level sets

A new variational level set approach is proposed for lung nodule segmentation in lung CT scans. A general lung nodule shape model is proposed using implicit spaces as a signed distance function. The shape model is fused with the image intensity statistical information in a variational segmentation framework. The nodule shape model is mapped to the image domain by a global transformation that includes inhomogeneous scales, rotation, and translation parameters. A matching criteria between the shape model and the image implicit representations is employed to handle the alignment process. Transformation parameters evolve through gradient descent optimization to handle the shape alignment process and hence mark the boundaries of the nodule “head.” The embedding process takes into consideration the image intensity as well as prior shape information. A nonparametric density estimation approach is employed to handle the statistical intensity representation of the nodule and background regions. The proposed technique does not depend on nodule type or location. Exhaustive experimental and validation results are demonstrated on 742 nodules obtained from four different CT lung databases, illustrating the robustness of the approach.

Current status of lung cancer screening

Low-dose CT (LDCT) is effective in the early detection of lung cancer, providing higher resectability and long-term survival rates. The National Lung Screening Trial shows a statistically significant mortality reduction in LDCT compared with chest radiography. The efficacy and safety of annual LDCT screening in heavy smokers must be explored, and the magnitude of benefit compared with the cost of large-scale screening. Trials in Europe have different study designs and an observational arm. Strategies to reduce lung cancer mortality should combine early detection with primary prevention and innovative biologic approaches.

Characterisation of solitary pulmonary lesions combining visual perfusion and quantitative diffusion MR imaging

OBJECTIVE

To evaluate the diagnostic accuracy of dynamic contrast-enhanced (DCE) magnetic resonance (MR) and diffusion-weighted imaging (DWI) sequences for defining benignity or malignancy of solitary pulmonary lesions (SPL).

METHODS

First, 54 consecutive patients with SPL, clinically staged (CT and PET or integrated PET-CT) as N0M0, were included in this prospective study. An additional 3-Tesla MR examination including DCE and DWI was performed 1 day before the surgical procedure. Histopathology of the surgical specimen served as the standard of reference. Subsequently, this functional method of SPL characterisation was validated with a second cohort of 54 patients.

RESULTS

In the feasibility group, 11 benign and 43 malignant SPL were included. Using the combination of conventional MR sequences with visual interpretation of DCE-MR curves resulted in a sensitivity, specificity and accuracy of 100%, 55% and 91%, respectively. These results can be improved by DWI (with a cut-off value of 1.52 × 10(-3) mm(2)/s for ADChigh) leading to a sensitivity, specificity and accuracy of 98%, 82% and 94%, respectively. In the validation group these results were confirmed.

CONCLUSION

Visual DCE-MR-based curve interpretation can be used for initial differentiation of benign from malignant SPL, while additional quantitative DWI-based interpretation can further improve the specificity.

KEY POINTS

• Magnetic resonance imaging is increasingly being used to help differentiate lung lesions. • Solitary pulmonary lesions (SPL) are accurately characterised by combining DCE-MRI and DWI. • Visual DCE-MRI assessment facilitates the diagnostic throughput in patients with SPL. • DWI provides additional information in inconclusive DCE-MRI (type B pattern).

Imaging in childhood cancer: a Society for Pediatric Radiology and Children's Oncology Group Joint Task Force report

Contemporary medical imaging is a cornerstone of care for children with cancer. As 5-year survival rates for children with cancer exceed 80%, imaging technologies have evolved in parallel to include a wide array of modalities. Here, we overview the risks and benefits associated with commonly used imaging modalities and survey the current landscape of medical imaging for children with cancer. We find evidence-based imaging guidelines to assist in protocol development and to guide decision-making for optimal patient care are often lacking. The substantial variation in protocol-based recommendations for imaging both during and following therapy may hinder optimal clinical research and clinical care for children with cancer.

Computer-aided diagnosis systems for lung cancer: challenges and methodologies

This paper overviews one of the most important, interesting, and challenging problems in oncology, the problem of lung cancer diagnosis. Developing an effective computer-aided diagnosis (CAD) system for lung cancer is of great clinical importance and can increase the patient's chance of survival. For this reason, CAD systems for lung cancer have been investigated in a huge number of research studies. A typical CAD system for lung cancer diagnosis is composed of four main processing steps: segmentation of the lung fields, detection of nodules inside the lung fields, segmentation of the detected nodules, and diagnosis of the nodules as benign or malignant. This paper overviews the current state-of-the-art techniques that have been developed to implement each of these CAD processing steps. For each technique, various aspects of technical issues, implemented methodologies, training and testing databases, and validation methods, as well as achieved performances, are described. In addition, the paper addresses several challenges that researchers face in each implementation step and outlines the strengths and drawbacks of the existing approaches for lung cancer CAD systems.

Updates in percutaneous lung biopsy: new indications, techniques and controversies

The objective of percutaneous chest biopsy is to consistently reach the amount of tissue required to meet or exceed published diagnostic accuracy rates. Many recent publications have reevaluated the subject of chest biopsy to assess borderline or controversial indications such as very small lesions, ground-glass opacities, and cases with a past nondiagnostic percutaneous biopsy. In addition, publications have reviewed sample adequacy for the accurate determination of molecular markers. These new indications promise to expand the numbers of biopsy procedures performed by radiologists. This article discusses the current role of image-guided percutaneous lung biopsies in the management of patients with pulmonary malignancies.

Clinical management of solitary pulmonary micronodule: a pilot study

BACKGROUND

Solitary pulmonary micronodules (SPMN) characteristically have a diameter of 0.1-0.5cm.

OBJECTIVE

The aim of this prospective study is to evaluate the surgical approach to SPMN in order to establish the most appropriate treatment.

METHODS

Between January 2007 and June 2011, 146 SPMN patients (94 males and 52 females) were prospectively evaluated. Patients were divided into two groups based on history of malignancy (Group A, 59 patients) and generic risk factors for lung cancer (Group B, 87 patients). After gathering patient information, we proposed surgery or thin-section computed tomography (TSCT) follow-up to both Groups.

RESULTS

Preference for surgery versus TSCT follow-up was 90% versus 10% in Group A and 78% versus 22% in Group B, respectively. In Group A, we discovered 46 metastases from previous cancer (78%), 8 primary lung cancers (14%) and 5 benign lesions (8%). In Group B, we found 5 metastases (6%), 13 non-small-cell lung cancer (15%) and 69 benign lesions (79%). Statistical analysis revealed a high positive predictive value (PPV = 0.9) between total surgical patients versus TSCT follow-up patients.

CONCLUSIONS

The indication for surgery in solitary pulmonary micronodules is aimed at establishing early diagnosis and curing malignant disease. Our study indicates that in patients with previous cancer, surgery is essential. In patients with generic risk for lung cancer, surgical indications should be contemplated more carefully, even though the pulmonary malignancy rate of 21% in Group B seems to indicate the advisability of surgery.