Nodule characterization: subsolid nodules

CT-guided microcoil versus hook-wire localization of pulmonary nodule prior to video-assisted thoracoscopic surgery without fluoroscopic guidance

BACKGROUND

Both microcoils and hook-wires are commonly utilized for preoperative pulmonary nodule localization due to their convenience, but it remains unclear which one should be prioritized for recommendation.

AIMS

To compare the safety and efficacy of microcoils and hook-wires for pulmonary nodule localization.

METHODS

From January 2021 to December 2021, 310 consecutive patients (113 males and 197 females) with 341 pulmonary nodules who underwent CT-guided microcoil or hook-wire localization prior to video-assisted thoracoscopic surgery (VATS) at our center were retrospectively included in this study. There were 161 patients in the microcoil group and 149 patients in the hook-wire group. The successful localization rate, complication rate, radiation exposure, and medical costs were compared between the two groups.

RESULTS

A total of 341 pulmonary nodules were localized, with a success rate of 99% (180/184) in the microcoil group and 93% (146/157) in the hook-wire group, respectively. All patients successfully underwent VATS. Multivariate analysis revealed that hook-wire localization, shorter needle depth into the lung tissue and the longer waiting time from localization to VATS were the risk factors for the localization failure. The incidences of pneumothorax in the microcoil group and hook-wire group were 34.8% (56/161) and 34.9% (52/149), respectively (P = 0.983). The incidences of pneumorrhagia were 13% (24/184) and 46.5% (73/157), respectively (P = 0.000). Multivariate analysis revealed that hook-wire localization and greater depth of needle penetration into lung tissue were risk factors for pneumorrhagia.

CONCLUSION

Microcoil localization of pulmonary nodules is superior to hook-wire localization in terms of efficacy and safety. This finding provides insight into priority and broader promotion of microcoil localization.

Retrospective Analysis of Subsolid Nodules' Frequency Using Chest Computed Tomography Detection in an Outpatient Population

INTRODUCTION

The study was designed to evaluate the frequency of detection and the characteristics of subsolid nodules (SSNs) in outpatients' chest computed tomography (CT) scans from a private hospital in Southern Brazil.

METHODS

A retrospective analysis of all chest CT scans was performed in adult patients from ambulatory care (non-lung cancer screening population) over a thirty-day period. Inclusion criteria were age > 18 years and lung-scanning protocols, including standard-dose high-resolution chest CT (HRCT), enhanced CT, CT angiography, and low-dose chest CT (LDCT). SSNs main features collected were mean diameter, number, density (pure or heterogenous ground glass nodules and part-solid), and localization. TheLungRADS system and the updated Fleischner Society's pulmonary nodules recommendations were used for categorization only for study purposes, although not specifically fitting the population. The presence of emphysema, as well as calcified and solid nodules were also addressed. Statistical analysis was performed using R software, categorial variables are shown as absolute or relative frequencies, and continuous variables as mean and interquartile ranges.

RESULTS

Chest computed tomography were performed in 756 patients during the study period (September 2019), and 650 met the inclusion criteria. The IQR for age was 53/73 years; most participants were female (58.3%) and 10.6% had subsolid nodules detected.

CONCLUSIONS

The frequency of SSNs detection in patients in daily clinical practice, not related to screening populations, is not negligible. Regardless of the final etiology, follow-up is often indicated, given the likelihood of malignancy for persistent lesions.

Multiple fibrotic lung nodules in a patient with primary Sjögren's syndrome

Evaluation of bilateral lung nodules noted on imaging poses a diagnostic challenge to clinicians as it can have many differentials from benign to malignant causes. It becomes especially critical to identify them right when there are underlying autoimmune conditions and risk factors for infection. However, a thorough investigation can lead to the recognition of rare associations as described below. We present here a 57-year-old woman who was admitted to the hospital with shortness of breath. Imaging with a computed tomography (CT) scan showed that she had 8 bilateral cystic pulmonary nodules with focal areas of ground-glass opacity and mediastinal lymphadenopathy. Fibrobronchoscopy and histopathological studies were done on the right middle lobe lung nodule demonstrated that the lung nodule was fibrotic with reactive inflammation but showed no malignant cells. Upon further detailed history and chart review, it was noted that the patient had a history of dry eyes leading to an autoimmune workup showing positive antinuclear antibodies (ANA), anti-Ro, and anti-La antibodies with no follow-up since then. This lead to the suspicion that these nodules could be related to underlying Sjögren's syndrome. Initial inpatient management with intravenous steroids showed significant improvement in her symptomatology. Hence, we present this rare association of lung nodules with Sjögren's syndrome and its management for awareness of this condition.

Pearls and Pitfalls in Lung Cancer CT Screening

Annual LDCT lung cancer screening is recommended by the United States Preventive Services Task Force (USPSTF) for high-risk population based on the results from the National Lung Cancer Screening Trial (NLST) that showed a significant (20%) reduction in lung cancer-specific mortality rate with the use of annual low-dose computed tomography (LDCT) screening. More recently, the benefits of lung cancer screening were confirmed by the Dutch- Belgian NELSON trial in Europe. With the implementation of lung screening in large scale, knowledge of the limitations related to false positive, false negative and other potential pitfalls is essential to avoid misdiagnosis. This review outlines the most common potential pitfalls in the characterization of screen-detected lung nodules that include artifacts in LDCT, benign nodules that mimic lung cancer, and causes of false negative evaluations of lung cancer with LDCT and PET/CT studies. Awareness of the spectrum of potential pitfalls in pulmonary nodule detection and characterization, including equivocal or atypical presentations, is important for avoiding misinterpretation that can alter patient management.

Application Value of PET/CT and MRI in the Diagnosis and Treatment of Patients With Synchronous Multiple Pulmonary Ground-Glass Nodules

Background

Synchronous multiple ground-glass nodules (SMGGNs) in synchronous multiple lung cancers are associated with specific imaging findings. It is difficult to distinguish whether multiple nodules are primary tumors or metastatic lesions in the lungs. The need for PET/CT and contrast-enhanced brain MRI for these patients remains unclear. This study investigated the necessity of these two imaging examinations for SMGGN patients by means of retrospective analysis.

Methods

SMGGN patients who were diagnosed and treated in our hospital from October 2017 to May 2020 and underwent whole-body PET/CT(Cranial excepted) and/or contrast-enhanced brain MRI+DWI were enrolled in this study. We analyzed the imaging and clinical characteristics of these patients to evaluate SMGGN patients’ need to undergo whole-body PET/CT and brain MRI examination.

Results

A total of 87 SMGGN patients were enrolled. 51 patients underwent whole-body PET/CT examinations and did not show signs of primary tumors in other organs, metastatic foci in other organs, or metastasis to surrounding lymph nodes. 87 patients underwent whole-brain MRI, which did not reveal brain metastases but did detect an old cerebral infarction in 23 patients and a new cerebral infarction in one patient. 87 patients underwent surgical treatment in which 219 nodules were removed. All nodules were diagnosed as adenocarcinoma or atypical adenomatous hyperplasia. No lymph node metastasis was noted.

Conclusion

For SMGGN patients, PET/CT and enhanced cranial MRI are unnecessary for SMGGNs patients, but from the perspective of perioperative patient safety, preoperative MRI+DWI examination is recommended for SMGGNs patients.

Surgery for pre- and minimally invasive lung adenocarcinoma

OBJECTIVE

Adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) are the pre- and minimally invasive forms of lung adenocarcinoma. We aimed to investigate safety results and survival outcomes following different types of surgical resection in a large sample of patients with AIS/MIA.

METHODS

Medical records of patients with lung AIS/MIA who underwent surgery between 2012 and 2017 were retrospectively reviewed. Clinical characteristics, surgical types and complications, recurrence-free survival, and overall survival were investigated.

RESULTS

A total of 1644 patients (422 AIS and 1222 MIA) were included. The overall surgical complication rate was significantly lower in patients receiving wedge resection (1.0%), and was comparable between patients undergoing segmentectomy (3.3%) or lobectomy (5.6%). Grade ≥ 3 complications occurred in 0.1% of patients in the wedge resection group, and in a comparable proportion of patients in the segmentectomy group (1.5%) and the lobectomy group (1.5%). There was no lymph node metastasis. The 5-year recurrence-free survival rate was 100%. The 5-year overall survival rate in the entire cohort was 98.8%, and was comparable among the wedge resection group (98.8%), the segmentectomy group (98.2%), and the lobectomy group (99.4%).

CONCLUSIONS

Sublobar resection, especially wedge resection without lymph node dissection, may be the preferred surgical procedure for patients with AIS/MIA. If there are no risk factors, postoperative follow-up intervals may be extended. These implications should be validated in further studies.

What's New on Quantitative CT Analysis as a Tool to Predict Growth in Persistent Pulmonary Subsolid Nodules? A Literature Review

Pulmonary subsolid nodules (SSNs) are observed not infrequently on thin-section chest computed tomography (CT) images. SSNs persisting after a follow-up period of three to six months have a high likelihood of being pre-malignant or malignant lesions. Malignant SSNs usually represent the histologic spectrum of pulmonary adenocarcinomas, and pulmonary adenocarcinomas presenting as SSNs exhibit quite heterogeneous behavior. In fact, while most lesions show an indolent course and may grow very slowly or remain stable for many years, others may exhibit significant growth in a relatively short time. Therefore, it is not yet clear which persistent SSNs should be surgically removed and for how many years stable SSNs should be monitored. In order to solve these two open issues, the use of quantitative analysis has been proposed to define the "tailored" management of persistent SSNs. The main purpose of this review was to summarize recent results about quantitative CT analysis as a diagnostic tool for predicting the behavior of persistent SSNs. Thus, a literature search was conducted in PubMed/MEDLINE, Scopus, and Web of Science databases to find original articles published from January 2014 to October 2019. The results of the selected studies are presented and compared in a narrative way.

An unsupervised semi-automated pulmonary nodule segmentation method based on enhanced region growing

Background

Nowadays, computer technology is getting popular for clinical aided diagnosis, especially in the direction of medical images. It makes physician diagnosis of lung nodules more efficient by providing them with reliable and accurate segmentation.

Methods

A region growing based semi-automated pulmonary nodule segmentation algorithm (ReGANS) was developed with three improvements: an automatic threshold calculation method, a lesion area pre-projection method, and an optimized region growing method. The algorithm can quickly and accurately segment a whole lung nodule in a set of computed tomography (CT) images based on an initial manual point.

Results

The average time taken for ReGANS to segment 1 pulmonary nodule was 0.83s, and the probability rand index (PRI), global consistency error (GCE), and variation of information (VoI) from a comparison between the algorithm and the radiologist's 2 manual results were 0.93, 0.06, and 0.3 for the boundary range (BR), and 0.86, 0.06, 0.3 for the precise range (PR). The number of images covered by one pulmonary nodule in a CT image set was also evaluated to compare the segmentation algorithm with the radiologist's results, with an error rate of 15%. At the same time, the results were verified in multiple data sets to validate the robustness.

Conclusions

Compared with other algorithms, ReGANS can segment the lung nodule image region more quickly and more precisely. The experimental results show that ReGANS can assist medical imaging diagnosis and has good clinical application value. It also provides a faster and more convenient method for pre-data preparation of intelligent algorithms.

Whole-Lesion Computed Tomography-Based Entropy Parameters for the Differentiation of Minimally Invasive and Invasive Adenocarcinomas Appearing as Pulmonary Subsolid Nodules

OBJECTIVE

The aim of this study was to investigate the differentiation of computed tomography (CT)-based entropy parameters between minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IAC) lesions appearing as pulmonary subsolid nodules (SSNs).

METHODS

This study was approved by the institutional review board in our hospital. From July 2015 to November 2018, 186 consecutive patients with solitary peripheral pulmonary SSNs that were pathologically confirmed as pulmonary adenocarcinomas (74 MIA and 112 IAC lesions) were included and subdivided into the training data set and the validation data set. Chest CT scans without contrast enhancement were performed in all patients preoperatively. The subjective CT features of the SSNs were reviewed and compared between the MIA and IAC groups. Each SSN was semisegmented with our in-house software, and entropy-related parameters were quantitatively extracted using another in-house software developed in the MATLAB platform. Logistic regression analysis and receiver operating characteristic analysis were performed to evaluate the diagnostic performances. Three diagnostic models including subjective model, entropy model, and combined model were built and analyzed using area under the curve (AUC) analysis.

RESULTS

There were 119 nonsolid nodules and 67 part-solid nodules. Significant differences were found in the subjective CT features among nodule type, lesion size, lobulated shape, and irregular margin between the MIA and IAC groups. Multivariate analysis revealed that part-solid type and lobulated shape were significant independent factors for IAC (P < 0.0001 and P < 0.0001, respectively). Three entropy parameters including Entropy-0.8, Entropy-2.0-32, and Entropy-2.0-64 were identified as independent risk factors for the differentiation of MIA and IAC lesions. The median entropy model value of the MIA group was 0.266 (range, 0.174-0.590), which was significantly lower than the IAC group with value 0.815 (range, 0.623-0.901) (P < 0.0001). Multivariate analysis revealed that the combined model had an excellent diagnostic performance with sensitivity of 88.2%, specificity of 73.0%, and accuracy of 82.1%. The AUC value of the combined model was significantly higher (AUC, 0.869) than that of the subjective model (AUC, 0.809) or the entropy model alone (AUC, 0.836) (P < 0.0001).

CONCLUSIONS

The CT-based entropy parameters could help assess the aggressiveness of pulmonary adenocarcinoma via quantitative analysis of intratumoral heterogeneity. The MIA can be differentiated from IAC accurately by using entropy-related parameters in peripheral pulmonary SSNs.

Synchronous multiple lung cancers presenting as multifocal pure ground glass nodules: are whole-body positron emission tomography/computed tomography and brain enhanced magnetic resonance imaging necessary?

Background

Multifocal ground glass nodules (GGNs) represent a special radiological pattern indicative of synchronous multiple lung cancers (SMLCs), especially adenocarcinoma. However, the necessity of performing whole-body positron emission tomography/computed tomography (PET-CT) scanning and brain enhanced magnetic resonance imaging (MRI) as a staging workup for multifocal pure GGN (pGGN) patients remains unclear. The purpose of this study was to determine the utility of these two imaging scans for patients with multifocal pGGNs.

Methods

This retrospective study was reviewed and approved by the ethics committee of the Cancer Hospital of the Chinese Academy of Medical Sciences. The study cohort was retrospectively selected from patients with multifocal pGGNs who underwent whole-body PET-CT examinations and/or brain enhanced MRIs between January 2010 and February 2019 at our institution. The additional value of the two exams for detecting nodal and distant metastases was evaluated.

Results

In total, 73 patients (male-to-female ratio, 20:53; median age, 57 years) with multifocal pGGNs who underwent whole-body PET-CT (55 patients) and/or brain enhanced MRI (25 patients) were enrolled. No clearly metastatic lesions were detected. Among the enrolled patients, 53 (128 pGGNs) underwent complete surgical resection. All pGGNs were adenocarcinomas and/or preneoplasias, and no lymph node metastases were found on final pathology. Whole-body PET-CT and brain enhanced MRI added no definite benefit compared with chest CT alone before surgery.

Conclusions

Whole-body PET-CT scans and brain enhanced MRIs are not necessary for patients with multifocal pGGNs.

Computed tomography-guided cyanoacrylate localization of small pulmonary nodules: feasibility and initial experience

OBJECTIVES

We report our initial technical experience with computed tomography (CT)-guided cyanoacrylate localization for resection of small pulmonary nodules (SPNs) and evaluate the feasibility of this technique.

METHODS

Between June 2016 and December 2017, the diagnostic results of 55 consecutive patients (69 SPNs) who underwent preoperative CT-guided cyanoacrylate localization and consequent video-assisted thoracoscopic surgery (VATS) resection were retrospectively evaluated. Localization-related outcomes and perioperative outcomes were assessed.

RESULTS

Preoperative CT-guided cyanoacrylate localization was successfully performed in all the cases. Simultaneous localization was achieved in 8 (14.5%) patients with 2 nodules and 3 (5.5%) patients with 3 nodules. The mean size of the nodules was 8.5 ± 3.2 mm (range 5-20 mm), and their mean depth from the nearest pleural surface was 10.9 ± 7.7 mm (range 2-36 mm). The overall mean localization procedural time was 13.7 ± 7.2 min (range 6-37 min). Two localization-related complications (intrapulmonary focal haemorrhage and pneumothorax) were observed in 7 (12.7%) and 12 (21.8%) patients, respectively. All patients with complications were asymptomatic and received conservative treatment only. All SPNs were resected under VATS without any conversion to minithoracotomy or thoracotomy.

CONCLUSIONS

CT-guided cyanoacrylate localization is a feasible procedure to localize SPNs. The advantages of this technique include flexibility between insertion and excision, the ability to be applied to the whole lung field, a high success rate, patient comfort after insertion and a fast learning curve. Further studies are warranted to confirm the efficacy of this technique.

18F-fluorodeoxyglucose positron emission tomography/computed tomography in the diagnosis of benign pulmonary lesions in sarcoidosis

Background

Many benign pulmonary lesions, especially sarcoidosis, are metabolically active and are indistinguishable from lung cancer using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) imaging. This study sought to analyze the 18F-FDG PET/CT imaging features of benign pulmonary lesions and to improve the differential diagnosis of benign pulmonary lesions by 18F-FDG PET/CT imaging.

Methods

One hundred and thirteen patients with benign pulmonary lesions were studied retrospectively. Each patient underwent an 18F-FDG PET/CT scan. All cases were identified by pathology, diagnostic therapy or follow-up. The maximum standardized uptake value (SUVmax) was calculated for each pulmonary lesion.

Results

According to the final results, the benign pulmonary lesions were classified as inflammatory lesions (n=77) and granulomas (n=36) by histopathological diagnoses. The SUVmax of inflammatory lesions and granulomas were both high (4.55±2.77 and 6.81±3.96, respectively; P<0.05). When the benign pulmonary lesions were classified by clinical diagnoses, the SUVmax of sarcoidosis was significantly different from other diseases (15.12±5.67; P<0.01).

Conclusions

Inflammatory lesions and granulomas show moderate or high FDG uptake on 18F-FDG PET/CT, but granulomas have higher values. 18F-FDG PET/CT appeared to have a higher SUVmax for the differential diagnosis of sarcoidosis and benign pulmonary lesions.

Quantitative feature analysis of CT images of transbronchial dye markings mimicking true pulmonary ground-glass opacity lesions

Background

Transbronchial dye marking is a preoperative localization technique aiding pulmonary resection. Post-marking computed tomography (CT) is performed to confirm the locations of the actual markings. This study aimed to evaluate the CT images of dye markings that present as ground-glass opacities (GGO), using quantitative feature analysis.

Methods

Thin-slice (1 mm) CT images of the dye markings and true ground glass nodule (GGN) lesions were obtained for quantitative analysis with gray-level co-occurrence matrix (GLCM) features. The quantification features including correlation, auto correlation, contrast, energy, entropy, and homogeneity were evaluated. Statistical analysis with boxplot was performed.

Results

GLCM features of multi-detector computed tomography (MDCT) images of the dye markings (n=13) and true GGN lesions (n=13) differed significantly in contrast, energy, entropy, auto correlation, and homogeneity. Cone beam computed tomographic (CBCT) image features of another group of dye markings (n=15) also showed a different distribution of feature values, than those of the MDCT images.

Conclusions

Quantitative analysis of the dye marking images revealed a discriminative variance, compared with those of the true GGN lesions. Furthermore, the image textures of dye markings on MDCT and CBCT also presented with obvious discrepancies.

Identification of epidermal growth factor receptor mutations in pulmonary adenocarcinoma using dual-energy spectral computed tomography

OBJECTIVES

To explore the role of dual-energy spectral computed tomography (DESCT) quantitative characteristics for the identification of epidermal growth factor receptor (EGFR) mutation status in a cohort of East Asian patients with pulmonary adenocarcinoma.

MATERIALS AND METHODS

Patients with lung adenocarcinoma who underwent both DESCT chest examination and EGFR test were retrospectively selected from our institution's database. The DESCT visual morphological features and quantitative parameters, including the CT number at 70 keV, normalized iodine concentration (NIC), normalized water concentration, and slopes of the spectral attenuation curves (slope λ HU [Hounsfield unit]), were evaluated or calculated. The patients were divided into two groups: the EGFR mutation group and EGFR wild-type group. Statistical analyses were performed to identify the DESCT quantitative parameters for diagnosis of EGFR mutation status.

RESULTS

EGFR mutations were detected in 66 (55.0%) of the 120 enrolled patients. The univariate analysis revealed that sex, smoking history, CT texture, NIC, and slope λ HU were significantly associated with EGFR mutation status (p = 0.037, 0.001, 0.047, 0.010, and 0.018, respectively). The multivariate logistic analysis revealed that smoking history (odds ratio [OR] = 3.23, p = 0.005) and NIC (OR = 58.026, p = 0.049) were the two significant predictive factors associated with EGFR mutations. Based on this analysis, the smoking history and NIC were combined to determine the predictive value for EGFR mutations with the area under the curve of 0.702.

CONCLUSIONS

NIC may be a potential quantitative DESCT parameter for predicting EGFR mutations in patients with pulmonary adenocarcinoma.

KEY POINTS

• DESCT can provide multiple quantitative image parameters compared to conventional CT. • Identification of the radio-genomic relation between DESCT and EGFR status can help to define molecular subcategories of lung adenocarcinoma, which is valuable for personalized clinical targeted therapy. • NIC may be a potential DESCT quantitative parameter for predicting EGFR mutations in pulmonary adenocarcinoma.

Combined lipiodol marking and video-assisted thoracoscopic surgery in a hybrid operating room

Background

The development of diagnostic technology has led to detection of an increasing number of small pulmonary nodules (SPNs), which can be difficult to locate intraoperatively. Here, we report our experience performing single-stage lipiodol localization and surgical resection in a hybrid operating room (OR).

Methods

Between June 2016 and August 2017, 30 patients with 32 SPNs underwent sliding gantry-based multidetector computed tomography (MDCT)-guided lipiodol marking followed by video-assisted thoracoscopic surgery (VATS) in a hybrid OR. After induction of general anesthesia, all nodules were marked with 0.2 mL lipiodol under MDCT fluoroscopic guidance, followed by immediate VATS.

Results

The mean SPN diameter and distance from the pleural surface were 10.7±4.5 mm (range, 5.0-21.0 mm) and 18.0±9.0 mm (range, 2.8-32.0 mm) respectively. The MDCT-guided localization procedure required 15.8±6.0 min (range, 8.0-32.0 min). All the nodules were marked with lipiodol and detected during fluoroscopy as a clear spot. The median deviation between the radio-opaque nodule and the target nodule was 7.8±3.6 mm (range, 3.0-20.0 mm). In two cases, MDCT scans performed after completion of marking revealed mild pneumothorax, which did not need further intervention. VATS resection was converted to thoracotomy in two patients because of strong pleural adhesions and intraoperative bleeding from the pulmonary vein. No other complications occurred during the combined approach, and there was no intra- or post-operative mortality or morbidity.

Conclusions

These results suggest that a combined approach using MDCT-guided lipiodol marking followed by VATS is feasible and has acceptable accuracy in resection of SPNs.

Treatment of pulmonary nodule: from VATS to RATS

Background

The incidental detection of solitary pulmonary nodule (SPN) is currently increasing due to the widespread use of computed tomography (CT) during the follow up in oncological patients or in screening trials. A quick and definitive histological diagnosis of these nodes is mandatory as, in case of primitive lung cancer, an early detection could improve both surgical results and prognosis. The minimally invasive pulmonary resection (MIPR) is the gold standard procedure for diagnosis and treatment of small lung nodules, but it can be difficult to localize deep nonpalpable nodes that lie in the lung parenchyma. Hence, throughout the years several techniques have been developed to better localize deep or sub solid nodes. We describe our experience with radio-guided technique.

Methods

Patients with SPN smaller than 10 mm and/or with a distance from the visceral pleura equal or larger than 10 mm underwent MIPR after CT injection of a solution containing 0.2 mL ⁹⁹Tc-labelled human serum albumin microspheres and 0.1 mL of non-ionic contrast. During surgical procedures, a collimated probe, connected to a gamma-ray detector, was used to scan the lung and detect the target area. The area of major radioactivity was then resected.

Results

Between 2010 and 2015, 175 patients (M/F: 97/78) underwent minimally invasive resection (thoracoscopic or robotic) with radio-guided technique. The mean node diameter was 13 mm (range, 5-20 mm), and the mean distance from the visceral pleura was 15 mm (range, 6-39 mm). No significant CT-guided-injection-related complications occurred, except for 13 patients (7.4%) who developed a pneumothorax (PNX) not requiring chest tube insertion. This technique guaranteed a successfully intra-operative node localization in 100% of cases. The mean duration of the surgical procedure was 44 min (range, 25-130 min). The mean length of pleural drainage and mean hospital stay was 2.6 days (range, 1-5 days) and 3.9 days (range, 1-7 days) respectively. No mortality or perioperative complications occurred. Pathology reports showed 105 metastases, 55 primitive lung cancers and 15 benign lesions. In case of suspicion of primitive lung tumour an intraoperative frozen exam was conducted, and all patients underwent lobectomy or segmentectomy with lymphadenectomy [41 patients with thoracotomy, 11 with robotic surgery and 3 with video-assisted thoracoscopic surgery (VATS)].

Conclusions

Our experience confirms that radio-guided thoracoscopic surgery (RGTS) is a feasible and safe procedure, thanks to its high success rate the radio-guided technique is helpful to overcome the lack of tactile feedback during MIPR [VATS and robotic-assisted thoracoscopic surgery (RATS)] and to limit conversion to open surgery.

The impact of chemotherapy on persistent ground-glass nodules in patients with lung adenocarcinoma

Backgrounds

To evaluate the response of persistent ground glass nodules (GGNs) in patients with lung adenocarcinoma treated with platinum-based chemotherapy on computed tomography (CT).

Methods

We retrospectively studied patients with GGNs that met the following criteria: (I) GGNs found in patients with lung adenocarcinoma, which persist for more than 3 months; (II) patients treated with platinum-based (cisplatin or carboplatin) chemotherapy for at least 2 cycles; (III) ground glass proportion ¡Ý50%. For each patient, if more than two CTs satisfied the inclusion criteria, then the baseline and last CTs were used for analysis, defined as CT1 and CT2. A total of 91 persistent pulmonary GGNs in 51 patients fulfilled the inclusion criteria. We defined growth as a nodule ¡Ý2 mm increase in diameter or showing up a solid portion. GGN response to therapy was assessed and compared with the baseline CT. Differences in CT findings were analyzed using a paired t-test and Pearson ¦Ö² test.

Results

Between 2010 and 2015, 25 of the 51 (49%) were male and 26 of the 51 (51%) were female. The average age at time of detection of a GGN was 63.8 (range, 36-84) years. Mean follow-up duration was 24.1¡À17.9 months. During the follow-up periods, on a per-nodule basis, 94.5% of GGNs (n=86) remained unchanged in size. Only 5.5% GGNs (n=5) in 5 patients increased in size. The nodules CT feature in each lung adenocarcinoma clinical stage show no difference. No significant difference was found in the size, attenuation, volume, and mass of GGN between baseline and post-treatment measurements, regardless of the type of chemotherapy (P>0.05).

Conclusions

The clinical course of GGNs in patients with lung adenocarcinoma is predominantly indolent, and platinum-based chemotherapy may have no effect on the growth of persistent GGNs.

[Combined use of thin-section CT and 18F-FDG PET/CT for characterization of solitary pulmonary nodules]

OBJECTIVE

To investigate whether fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) combined with thin-section CT improves the diagnostic performance for solitary pulmonary nodules (SPNs).

METHODS

A total of 267 patients underwent examinations with 18F-FDG PET/CT and thin-section CT for evaluating the SPNs with undetermined nature, which was further confirmed by pathological examination or clinical follow-up. The performance of two diagnostic criteria based on findings in PET/CT alone (Criterion 1) and in PET/CT combined with thin-section CT (Criterion 2) were compared.

RESULTS

Thin-section CT provided greater diagnostic information for SPNs in 84.2% of the patients. Compared with Criterion 1, the diagnosis based on Criterion 2 significantly increased the diagnostic sensitivity (80.4% vs 91%, P&lt;0.01) and accuracy (76.4% vs 87.2%, P<0.01) for lung cancer. The lesion size and the CT features including lobulation, air bronchogram, and feeding vessel, but not SUV_max, were all helpful for characterizing non-solid SPNs. Thin-section CT rectified diagnostic errors in 50% (20/40) of the cancerous lesions, which had been diagnosed as benign by PET due to their low metabolism. For non-solid SPNs, Criterion 2 showed a significantly higher diagnostic sensitivity than Criterion 1 (90.0% vs 40.0%, P=0.000) but their diagnostic specificity were comparable (75.2% vs 58.3%, P=0.667). For solid nodules, the use of thin-section CT resulted in no significant improvement in the diagnostic performance (P>0.05).

CONCLUSION

The combination of PET/CT and thin-section CT creates a synergistic effect for the characterization of SPNs, especially non-solid nodules.

Computer-aided detection of pulmonary nodules using dynamic self-adaptive template matching and a FLDA classifier

Improving the performance of computer-aided detection (CAD) system for pulmonary nodules is still an important issue for its future clinical applications. This study aims to develop a new CAD scheme for pulmonary nodule detection based on dynamic self-adaptive template matching and Fisher linear discriminant analysis (FLDA) classifier. We first segment and repair lung volume by using OTSU algorithm and three-dimensional (3D) region growing. Next, the suspicious regions of interest (ROIs) are extracted and filtered by applying 3D dot filtering and thresholding method. Then, pulmonary nodule candidates are roughly detected with 3D dynamic self-adaptive template matching. Finally, we optimally select 11 image features and apply FLDA classifier to reduce false positive detections. The performance of the new method is validated by comparing with other methods through experiments using two groups of public datasets from Lung Image Database Consortium (LIDC) and ANODE09. By a 10-fold cross-validation experiment, the new CAD scheme finally has achieved a sensitivity of 90.24% and a false-positive (FP) of 4.54 FP/scan on average for the former dataset, and a sensitivity of 84.1% with 5.59 FP/scan for the latter. By comparing with other previously reported CAD schemes tested on the same datasets, the study proves that this new scheme can yield higher and more robust results in detecting pulmonary nodules.

Image-guided thoracoscopic surgery with dye localization in a hybrid operating room

BACKGROUND

The rate of detection of small pulmonary nodules (SPNs) has increased. Thoracoscopic resection following image-guided localization had been a reliable alternative in their treatment. We present our experience with image-guided dye localization using robotic C-arm computed tomography (CT) followed by immediate video-assisted thoracoscopic surgery (VATS) for SPNs in a hybrid operating room (OR).

METHODS

From July 2015 to July 2016, 25 consecutive patients with SPNs smaller than 2 cm underwent robotic C-arm CT-guided blue dye tattooing followed by immediate VATS in a hybrid OR. Their medical records were retrospectively reviewed to evaluate the feasibility and safety of this novel procedure.

RESULTS

Robotic C-arm CT-guided dye localization was successfully performed in 23 patients (92%). Wound extension was required for nodule identification in the remaining two patients. The median size of the nodules was 1.0 cm (range, 0.6-2.0 cm). The median needle localization time and surgery time were 46 and 109 min, respectively. All 25 patients had successful resection of their lesions. The pathological diagnoses were primary lung adenocarcinoma in 18 (72%), benign tumors in 5 (20%), and metastatic lesions in 2 (8%). There was no operative mortality. The median length of the postoperative stay was 3 days (range, 2-8 days). Complications were noted in two patients (8%). One patient had a penetrating injury of the diaphragm during needle localization. The other had pneumonia postoperatively. Both patients were managed conservatively.

CONCLUSIONS

Our experience showed that robotic C-arm CT-guided dye localization followed by immediate thoracoscopic surgery in a hybrid OR is safe and feasible. It may become an effective and attractive alternative in managing SPNs.

Subsolid pulmonary nodule morphology and associated patient characteristics in a routine clinical population

OBJECTIVES

To determine the presence and morphology of subsolid pulmonary nodules (SSNs) in a non-screening setting and relate them to clinical and patient characteristics.

METHODS

A total of 16,890 reports of clinically obtained chest CT (06/2011 to 11/2014, single-centre) were searched describing an SSN. Subjects with a visually confirmed SSN and at least two thin-slice CTs were included. Nodule volumes were measured. Progression was defined as volume increase exceeding the software interscan variation. Nodule morphology, location, and patient characteristics were evaluated.

RESULTS

Fifteen transient and 74 persistent SSNs were included (median follow-up 19.6 [8.3-36.8] months). Subjects with an SSN were slightly older than those without (62 vs. 58 years; p = 0.01), but no gender predilection was found. SSNs were mostly located in the upper lobes. Women showed significantly more often persistent lesions than men (94 % vs. 69 %; p = 0.002). Part-solid lesions were larger (1638 vs. 383 mm³; p < 0.001) and more often progressive (68 % vs. 38 %; p = 0.02), compared to pure ground-glass nodules. Progressive SSNs were rare under the age of 50 years. Logistic regression analysis did not identify additional nodule parameters of future progression, apart from part-solid nature.

CONCLUSIONS

This study confirms previously reported characteristics of SSNs and associated factors in a European, routine clinical population.

KEY POINTS

• SSNs in women are significantly more often persistent compared to men. • SSN persistence is not associated with age or prior malignancy. • The majority of (persistent) SSNs are located in the upper lung lobes. • A part-solid nature is associated with future nodule growth. • Progressive solitary SSNs are rare under the age of 50 years.

Solid, part-solid, or non-solid?: classification of pulmonary nodules in low-dose chest computed tomography by a computer-aided diagnosis system

OBJECTIVES

The purpose of this study was to develop and validate a computer-aided diagnosis (CAD) tool for automatic classification of pulmonary nodules seen on low-dose computed tomography into solid, part-solid, and non-solid.

MATERIALS AND METHODS

Study lesions were randomly selected from 2 sites participating in the Dutch-Belgian NELSON lung cancer screening trial. On the basis of the annotations made by the screening radiologists, 50 part-solid and 50 non-solid pulmonary nodules with a diameter between 5 and 30 mm were randomly selected from the 2 sites. For each unique nodule, 1 low-dose chest computed tomographic scan was randomly selected, in which the nodule was visible. In addition, 50 solid nodules in the same size range were randomly selected. A completely automatic 3-dimensional segmentation-based classification system was developed, which analyzes the pulmonary nodule, extracting intensity-, texture-, and segmentation-based features to perform a statistical classification. In addition to the nodule classification by the screening radiologists, an independent rating of all nodules by 3 experienced thoracic radiologists was performed. Performance of CAD was evaluated by comparing the agreement between CAD and human experts and among human experts using the Cohen κ statistics.

RESULTS

Pairwise agreement for the differentiation between solid, part-solid, and non-solid nodules between CAD and each of the human experts had a κ range between 0.54 and 0.72. The interobserver agreement among the human experts was in the same range (κ range, 0.56-0.81).

CONCLUSIONS

A novel automated classification tool for pulmonary nodules achieved good agreement with the human experts, yielding κ values in the same range as the interobserver agreement. Computer-aided diagnosis may aid radiologists in selecting the appropriate workup for pulmonary nodules.

Advances in lung adenocarcinoma classification: a summary of the new international multidisciplinary classification system (IASLC/ATS/ERS)

Due to advances in the understanding of lung adenocarcinoma since the advent of its 2004 World Health System classification, an international multidisciplinary panel [sponsored by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS)] has recently updated the classification system for lung adenocarcinoma, the most common histologic type of lung cancer. Here, we summarize and highlight the new criteria and terminology, certain aspects of its clinical relevance and its potential treatment impact, and future avenues of research related to the new system.

Indeterminate pulmonary nodules: risk for having or for developing lung cancer?

This perspective discusses the report by Pinsky and colleagues, which addresses whether noncalcified pulmonary nodules identified on CT screening carry short- and long-term risk for lung cancer. We are facing challenges related to distinguishing a large majority of benign nodules from malignant ones and among those a majority of aggressive from indolent cancers. Key questions in determining individual probabilities of disease, given their history, findings on CT, and upcoming biomarkers of risk, remain most challenging. Reducing the false positives associated with current low-dose computed tomography practices and identification of individuals who need therapy and at what time during tumor surveillance could reduce costs and morbidities associated with unnecessary interventions.