Improving diagnostic strategies in bronchoscopy for peripheral pulmonary lesions.

INTRODUCTION: In the past two decades, bronchoscopy of peripheral pulmonary lesions (PPLs) has improved its diagnostic yield due to the combination of various instruments and devices. Meanwhile, the application is complex and intertwined. AREAS COVERED: This review article outlines strategies in diagnostic bronchoscopy for PPLs. We summarize the utility and evidence of key instruments and devices based on the results of clinical trials. Future perspectives of bronchoscopy for PPLs are also discussed. EXPERT OPINION: The accuracy of reaching PPLs by bronchoscopy has improved significantly with the introduction of combined instruments such as navigation, radial endobronchial ultrasound, digital tomosynthesis, and cone-beam computed tomography. It has been accelerated with the advent of approach tools such as newer ultrathin bronchoscopes and robotic-assisted bronchoscopy. In addition, needle aspiration and cryobiopsy provide further diagnostic opportunities beyond forceps biopsy. Rapid on-site evaluation may also play an important role in decision making during the procedures. As a result, the diagnostic yield of bronchoscopy for PPLs has improved to a level comparable to that of transthoracic needle biopsy. The techniques and technologies developed in the diagnosis will be carried over to the next step in the transbronchial treatment of PPLs in the future.

Dynamic reconstruction for digital tomosynthesis: a phantom proof of concept for breast care.

Objective. Digital tomosynthesis (DTS) is a type of limited-angle Computed Tomography (CT) used in orthopedic and oncology care to provide a pseudo-3D reconstructed volume of a body part from multiple x-ray projections. Patient motion during acquisitions results in artifacts which affect screening and diagnostic performances. Hence, accurate reconstruction of moving body parts from a tomosynthesis projection series is addressed in this paper, with a particular focus on the breast. The aim of this paper is to assess the feasibility of a novel dynamic reconstruction technique for DTS and evaluate its accuracy compared to an available ground truth.Approach. The proposed method is a combination of a 4D dynamic tomography strategy leveraging the formalism of Projection-based Digital Volume Correlation (P-DVC) with a multiscale approach to estimate and correct patient motion. Iterations of two operations are performed: (i) a motion-corrected reconstruction based on the Simultaneous Iterative Reconstruction Technique (SIRT) algorithm and (ii) a motion estimation from projection residuals, to obtain motion-free volumes. Performance is evaluated on a synthetic Digital Breast Tomosynthesis (DBT) case. Three slabs of a CIRS breast phantom are imaged on a Senographe PristinaTM, under plate-wise rigid body motions with amplitudes ranging up to 10 mm so that an independent measurement of the motion can be accessed.Results. Results show a motion estimation average precision down to 0.183 mm (1.83 voxels), when compared to the independent measurement. Moreover, an 84.2% improvement on the mean residual error and a 59.9% improvement on the root mean square error (RMSE) with the original static reconstruction are obtained.Significance. Visual and quantitative assessments of the dynamically reconstructed volumes show that the proposed method fully restores conspicuity for important clinical features contained in the phantom.

First-in-human use of a new robotic electromagnetic navigation bronchoscopic platform with integrated Tool-in-Lesion Tomosynthesis (TiLT) technology for peripheral pulmonary lesions: The FRONTIER study.

BACKGROUND AND OBJECTIVE: As the presentation of pulmonary nodules increases, the importance of a safe and accurate method of sampling peripheral pulmonary nodules is highlighted. First-generation robotic bronchoscopy has successfully assisted navigation and improved peripheral reach during bronchoscopy. Integrating tool-in-lesion tomosynthesis (TiLT) may further improve yield. METHODS: We performed a first-in-human clinical trial of a new robotic electromagnetic navigation bronchoscopy system with integrated digital tomosynthesis technology (Galaxy System, Noah Medical). Patients with moderate-risk peripheral pulmonary nodules were enrolled in the study. Robotic bronchoscopy was performed using electromagnetic navigation with TiLT-assisted lesion guidance. Non-specific results were followed up until either a clear diagnosis was achieved or repeat radiology at 6 months demonstrated stability. RESULTS: Eighteen patients (19 nodules) were enrolled. The average lesion size was 20 mm, and the average distance from the pleura was 11.6 mm. The target was successfully reached in 100% of nodules, and the biopsy tool was visualized inside the target lesion in all cases. A confirmed specific diagnosis was achieved in 17 nodules, 13 of which were malignant. In one patient, radiological monitoring confirmed a true non-malignant result. This translates to a yield of 89.5% (strict) to 94.7% (intermediate). Complications included one pneumothorax requiring observation only and another requiring an overnight chest drain. There was one case of severe pneumonia following the procedure. CONCLUSION: In this first-in-human study, second-generation robotic bronchoscopy using electromagnetic navigation combined with integrated digital tomosynthesis was feasible with an acceptable safety profile and demonstrated a high diagnostic yield for small peripheral lung nodules.

Imaging modalities during navigational bronchoscopy.

INTRODUCTION: Lung nodules are commonly encountered in clinical practice. Technological advances in navigational bronchoscopy and imaging modalities have led to paradigm shift from nodule screening or follow-up to early lung cancer detection. This is due to improved nodule localization and biopsy confirmation with combined modalities of navigational platforms and imaging tools. To conduct this article, relevant literature was reviewed via PubMed from January 2014 until January 2024. AREAS COVERED: This article highlights the literature on different imaging modalities combined with commonly used navigational platforms for diagnosis of peripheral lung nodules. Current limitations and future perspectives of imaging modalities will be discussed. EXPERT OPINION: The development of navigational platforms improved localization of targets. However, published diagnostic yield remains lower compared to percutaneous-guided biopsy. The discordance between the actual location of lung nodule during the procedure and preprocedural CT chest is the main factor impacting accurate biopsies. The utilization of advanced imaging tools with navigation-based bronchoscopy has been shown to assist with localizing targets in real-time and improving biopsy success. However, it is important for interventional bronchoscopists to understand the strengths and limitations of these advanced imaging technologies.

Diagnostic yield of dental radiography and digital tomosynthesis for the identification of anatomic structures in cats.

Introduction: Digital tomosynthesis (DT) has emerged as a potential imaging modality for evaluating anatomic structures in veterinary medicine. This study aims to validate the diagnostic yield of DT in identifying predefined anatomic structures in feline cadaver heads, comparing it with conventional intraoral dental radiography (DR). Methods: A total of 16 feline cadaver heads were utilized to evaluate 19 predefined clinically relevant anatomic structures using both DR and DT. A semi-quantitative scoring system was employed to characterize the ability of each imaging method to identify these structures. Results: DT demonstrated a significantly higher diagnostic yield compared to DR for all evaluated anatomic structures. Orthogonal DT imaging identified 13 additional anatomic landmarks compared to a standard 10-view feline set obtained via DR. Moreover, DT achieved statistically significant higher scores for each of these landmarks, indicating improved visualization over DR. Discussion: These findings validate the utility of DT technology in reliably identifying clinically relevant anatomic structures in the cat skull. This validation serves as a foundation for further exploration of DT imaging in detecting dentoalveolar and other maxillofacial bony lesions and pathologies in cats.

Target sign in COVID-19, radiological interpretation and diagnostic contribution of digital thoracic tomosynthesis.

INTRODUCTION: Our objectives are: To describe the radiological semiology, clinical-analytical features and prognosis related to the target sign (TS) in COVID-19. To determine whether digital thoracic tomosynthesis (DTT) improves the diagnostic ability of radiography. MATERIAL AND METHODS: Retrospective, descriptive, single-centre, case series study, accepted by our ethical committee. Radiological, clinical, analytical and follow-up characteristics of patients with COVID-19 and TS on radiography and DTT between November 2020 and January 2021 were analysed. RESULTS: Eleven TS were collected in 7 patients, median age 35 years, 57% male. All TS presented with a central nodule and a peripheral ring, and in at least 82%, the lung in between was of normal density. All TS were located in peripheral, basal regions and 91% in posterior regions. TS were multiple in 43%. Contiguous TS shared the peripheral ring. Other findings related to pneumonia were associated in 86% of patients. DTT detected 82% more TS than radiography. Only one patient underwent a CT angiography of the pulmonary arteries, positive for acute pulmonary thromboembolism. Seventy-one per cent presented with pleuritic pain. No distinctive laboratory findings or prognostic worsening were detected. CONCLUSIONS: TS in COVID-19 predominates in peripheral and declining regions and can be multiple. Pulmonary thromboembolism was detected in one case. It occurs in young people, frequently with pleuritic pain and does not worsen the prognosis. DTT detects more than 80 % of TS than radiography.

Deformable 3D/3D CT-to-digital-tomosynthesis image registration in image-guided bronchoscopy interventions.

Traditional navigational bronchoscopy procedures rely on preprocedural computed tomography (CT) and intraoperative chest radiography and cone-beam CT (CBCT) to biopsy peripheral lung lesions. This navigational approach is challenging due to the projective nature of radiography, and the high radiation dose, long imaging time, and large footprints of CBCT. Digital tomosynthesis (DTS) is considered an attractive alternative combining the advantages of radiography and CBCT. Only the depth resolution cannot match a full CBCT image due to the limited angle acquisition. To address this issue, preoperative CT is a good auxiliary in guiding bronchoscopy interventions. Nevertheless, CT-to-body divergence caused by anatomic changes and respiratory motion, hinders the effective use of CT imaging. To mitigate CT-to-body divergence, we propose a novel deformable 3D/3D CT-to-DTS registration algorithm employing a multistage, multiresolution approach and using affine and elastic B-spline transformation models with bone and lung mask images. A multiresolution strategy with a Gaussian image pyramid and a multigrid strategy within the B-spline model are applied. The normalized correlation coefficient is included in the cost function for the affine model and a multimetric weighted cost function is used for the B-spline model, with weights determined heuristically. Tested on simulated and real patient bronchoscopy data, the algorithm yields promising results. Assessed qualitatively by visual inspection and quantitatively by computing the Dice coefficient (DC) and the average symmetric surface distance (ASSD), the algorithm achieves mean DC of 0.82±0.05 and 0.74±0.05, and mean ASSD of 0.65±0.29mm and 0.93±0.43mm for simulated and real data, respectively. This algorithm lays the groundwork for CT-aided intraoperative DTS imaging in image-guided bronchoscopy interventions with future studies focusing on automated metric weight setting.

The use of digital tomosynthesis in suspected scaphoid fractures.

We report a retrospective observational series of patients undergoing digital tomosynthesis (DTS) for suspected scaphoid fractures. With a specificity and sensitivity of 100%, DTS demonstrates the potential to be an excellent tool in the diagnosis of occult scaphoid fractures.

Novel Technologies in Breast Imaging: A Scoping Review.

Breast cancer is one of the leading causes of death in the United States and can cause considerable suffering for not only the patient but their families as well. The current mainstay of screening is mammography, although this screening modality has its drawbacks. Multiple technologies have been recently explored in hopes of increasing breast cancer detection rates and decreasing false positive rates. Overall, improving breast cancer screening techniques has the potential to decrease cost, patient anxiety, and the use of unnecessary procedures. This review discusses multiple modalities including digital breast tomosynthesis, contrast-enhanced dual-energy digital mammography (CE DE DM), MRI with diffusion-weighted sequences and proton magnetic resonance spectroscopy. This paper was written with the objective of synthesizing information across several databases to provide clinicians with a more accessible tool to understand the underlying concepts behind these imaging modalities, as well as present reviewed data which highlights the benefits and drawbacks of these breast cancer-detecting techniques.

Digital wrist tomosynthesis (DWT)-based finite element analysis of ultra-distal radius differentiates patients with and without a history of osteoporotic fracture.

Despite effective therapies for those at risk of osteoporotic fracture, low adherence to screening guidelines and limited accuracy of bone mineral density (BMD) in predicting fracture risk preclude identification of those at risk. Because of high adherence to routine mammography, bone health screening at the time of mammography using a digital breast tomosynthesis (DBT) scanner has been suggested as a potential solution. BMD and bone microstructure can be measured from the wrist using a DBT scanner. However, the extent to which biomechanical variables can be derived from digital wrist tomosynthesis (DWT) has not been explored. Accordingly, we measured stiffness from a DWT based finite element (DWT-FE) model of the ultra-distal (UD) radius and ulna, and correlate these to reference microcomputed tomography image based FE (µCT-FE) from five cadaveric forearms. Further, this method is implemented to determine in vivo reproducibility of FE derived stiffness of UD radius and demonstrate the in vivo utility of DWT-FE in bone quality assessment by comparing two groups of postmenopausal women with and without a history of an osteoporotic fracture (Fx; n = 15, NFx; n = 51). Stiffness obtained from DWT and µCT had a strong correlation (R2 = 0.87, p < 0.001). In vivo repeatability error was <5 %. The NFx and Fx groups were not significantly different in DXA derived minimum T-scores (p > 0.3), but stiffness of the UD radius was lower for the Fx group (p < 0.007). Logistic regression models of fracture status with stiffness of the nondominant arm as the predictor were significant (p < 0.01). In conclusion this study demonstrates the feasibility of fracture risk assessment in mammography settings using DWT imaging and FE modeling in vivo. Using this approach, bone and breast screening can be performed in a single visit, with the potential to improve both the prevalence of bone health screening and the accuracy of fracture risk assessment.

Digital Tomosynthesis: Review of Current Literature and Its Impact on Diagnostic Bronchoscopy.

Bronchoscopy has garnered increased popularity in the biopsy of peripheral lung lesions. The development of navigational guided bronchoscopy systems along with radial endobronchial ultrasound (REBUS) allows clinicians to access and sample peripheral lesions. The development of robotic bronchoscopy improved localization of targets and diagnostic accuracy. Despite such technological advancements, published diagnostic yield remains lower compared to computer tomography (CT)-guided biopsy. The discordance between the real-time location of peripheral lesions and anticipated location from preplanned navigation software is often cited as the main variable impacting accurate biopsies. The utilization of cone beam CT (CBCT) with navigation-based bronchoscopy has been shown to assist with localizing targets in real-time and improving biopsy success. The resources, costs, and radiation associated with CBCT remains a hindrance in its wider adoption. Recently, digital tomosynthesis (DT) platforms have been developed as an alternative for real-time imaging guidance in peripheral lung lesions. In North America, there are several commercial platforms with distinct features and adaptation of DT. Early studies show the potential improvement in peripheral lesion sampling with DT. Despite the results of early observational studies, the true impact of DT-based imaging devices for peripheral lesion sampling cannot be determined without further prospective randomized trials and meta-analyses.

AI-based computer-aided diagnostic system of chest digital tomography synthesis: Demonstrating comparative advantage with X-ray-based AI systems.

BACKGROUND: Compared with chest X-ray (CXR) imaging, which is a single image projected from the front of the patient, chest digital tomosynthesis (CDTS) imaging can be more advantageous for lung lesion detection because it acquires multiple images projected from multiple angles of the patient. Various clinical comparative analysis and verification studies have been reported to demonstrate this, but there is no artificial intelligence (AI)-based comparative analysis studies. Existing AI-based computer-aided detection (CAD) systems for lung lesion diagnosis have been developed mainly based on CXR images; however, CAD-based on CDTS, which uses multi-angle images of patients in various directions, has not been proposed and verified for its usefulness compared to CXR-based counterparts. BACKGROUND AND OBJECTIVE: This study develops and tests a CDTS-based AI CAD system to detect lung lesions to demonstrate performance improvements compared to CXR-based AI CAD. METHODS: We used multiple (e.g., five) projection images as input for the CDTS-based AI model and a single-projection image as input for the CXR-based AI model to compare and evaluate the performance between models. Multiple/single projection input images were obtained by virtual projection on the three-dimensional (3D) stack of computed tomography (CT) slices of each patient's lungs from which the bed area was removed. These multiple images result from shooting from the front and left and right 30/60∘. The projected image captured from the front was used as the input for the CXR-based AI model. The CDTS-based AI model used all five projected images. The proposed CDTS-based AI model consisted of five AI models that received images in each of the five directions, and obtained the final prediction result through an ensemble of five models. Each model used WideResNet-50. To train and evaluate CXR- and CDTS-based AI models, 500 healthy data, 206 tuberculosis data, and 242 pneumonia data were used, and three three-fold cross-validation was applied. RESULTS: The proposed CDTS-based AI CAD system yielded sensitivities of 0.782 and 0.785 and accuracies of 0.895 and 0.837 for the (binary classification) performance of detecting tuberculosis and pneumonia, respectively, against normal subjects. These results show higher performance than the sensitivity of 0.728 and 0.698 and accuracies of 0.874 and 0.826 for detecting tuberculosis and pneumonia through the CXR-based AI CAD, which only uses a single projection image in the frontal direction. We found that CDTS-based AI CAD improved the sensitivity of tuberculosis and pneumonia by 5.4% and 8.7% respectively, compared to CXR-based AI CAD without loss of accuracy. CONCLUSIONS: This study comparatively proves that CDTS-based AI CAD technology can improve performance more than CXR. These results suggest that we can enhance the clinical application of CDTS. Our code is available at https://github.com/kskim-phd/CDTS-CAD-P.

A denoising model based on multi-agent reinforcement learning with data transformation for digital tomosynthesis.

Objective. Denoising models based on the supervised learning have been proposed for medical imaging. However, its clinical availability in digital tomosynthesis (DT) imaging is limited due to the necessity of a large amount of training data for providing acceptable image quality and the difficulty in minimizing a loss. Reinforcement learning (RL) can provide the optimal pollicy, which maximizes a reward, with a small amount of training data for implementing a task. In this study, we presented a denoising model based on the multi-agent RL for DT imaging in order to improve the performance of the machine learning-based denoising model.Approach. The proposed multi-agent RL network consisted of shared sub-network, value sub-network with a reward map convolution (RMC) technique and policy sub-network with a convolutional gated recurrent unit (convGRU). Each sub-network was designed for implementing feature extraction, reward calculation and action execution, respectively. The agents of the proposed network were assigned to each image pixel. The wavelet and Anscombe transformations were applied to DT images for delivering precise noise features during network training. The network training was implemented with the DT images obtained from the three-dimensional digital chest phantoms, which were constructed by using clinical CT images. The performance of the proposed denoising model was evaluated in terms of signal-to-noise ratio (SNR), structural similarity (SSIM) and peak signal-to-noise ratio (PSNR).Main results. Comparing the supervised learning, the proposed denoising model improved the SNRs of the output DT images by 20.64% while maintaining the similar SSIMs and PSNRs. In addition, the SNRs of the output DT images with the wavelet and Anscombe transformations were 25.88 and 42.95% higher than that for the supervised learning, respectively.Significance. The denoising model based on the multi-agent RL can provide high-quality DT images, and the proposed method enables the performance improvement of machine learning-based denoising models.

Digital Tomosynthesis as a Problem-Solving Technique to Confirm or Exclude Pulmonary Lesions in Hidden Areas of the Chest.

OBJECTIVES: To evaluate the capability of digital tomosynthesis (DTS) to characterize suspected pulmonary lesions in the so-called hidden areas at chest X-ray (CXR). MATERIALS AND METHODS: Among 726 patients with suspected pulmonary lesions at CXR who underwent DTS, 353 patients (201 males, 152 females; age 71.5 ± 10.4 years) revealed suspected pulmonary lesions in the apical, hilar, retrocardiac, or paradiaphragmatic lung zones and were retrospectively included. Two readers analyzed CXR and DTS images and provided a confidence score: 1 or 2 = definitely or probably benign pulmonary or extra-pulmonary lesion, or pulmonary pseudo-lesion deserving no further diagnostic work-up; 3 = indeterminate lesion; 4 or 5 = probably or definitely pulmonary lesion deserving further diagnostic work-up by CT. The nature of DTS findings was proven by CT (n = 108) or CXR during follow-up (n = 245). RESULTS: In 62/353 patients the suspected lung lesions were located in the lung apex, in 92/353 in the hilar region, in 59/353 in the retrocardiac region, and in 140/353 in the paradiaphragmatic region. DTS correctly characterized the CXR findings as benign pulmonary or extrapulmonary lesion (score 1 or 2) in 43/62 patients (69%) in the lung apex region, in 56/92 (61%) in the pulmonary hilar region, in 40/59 (67%) in the retrocardiac region, and in 106/140 (76%) in the paradiaphragmatic region, while correctly recommending CT in the remaining cases due to the presence of true solid pulmonary lesion, with the exception of 22 false negative findings (60 false positive findings). DTS showed a significantly (p < 0.05) increased sensitivity, specificity, and overall diagnostic accuracy and area under ROC curve compared to CXR alone. CONCLUSIONS: DTS allowed confirmation or exclusion of the presence of true pulmonary lesions in the hidden areas of the chest.

Shape-Sensing Robotic-Assisted Bronchoscopy vs Digital Tomosynthesis-Corrected Electromagnetic Navigation Bronchoscopy: A Comparative Cohort Study of Diagnostic Performance.

BACKGROUND: Electromagnetic navigational bronchoscopy has been the dominant bronchoscopic technology for targeting small peripheral lesions and now includes digital tomosynthesis-electromagnetic navigational bronchoscopy (DT-ENB), allowing near-real-time intraprocedural nodule visualization. Shape-sensing robotic-assisted bronchoscopy (ssRAB), with improved catheter stability and articulation recently became available. Although the diagnostic performance of these two methods seems higher than that of legacy systems, data remain limited. We sought to compare the diagnostic yield of these two novel platforms after their introduction at our institution. RESEARCH QUESTION: Does the diagnostic yield of ssRAB differ significantly from that of DT-ENB in patients undergoing biopsy of peripheral pulmonary lesions (PPLs)? STUDY DESIGN AND METHODS: This retrospective comparative cohort study analyzed prospectively collected data on consecutive procedures performed with DT-ENB and ssRAB in their first 6 months of use at our institution. Biopsies were considered diagnostic if histopathologic analysis revealed malignancy or specific benign features that readily explained the presence of a PPL. Nonspecific inflammation, normal lung or airway, and atypia not diagnostic of malignancy were considered nondiagnostic. RESULTS: SSRAB was used to biopsy 143 PPLs in 133 patients and DT-ENB was used to biopsy 197 PPLs in 170 patients. Diagnostic yield was 77% for ssRAB (110 of 143 PPLs) and 80% (158 of 197 PPLs) for DT-ENB (OR, 0.8; 95% CI, 0.5-1.4; P = .4). Median lesion diameters were 17 and 19 mm, respectively. No difference in diagnostic yield was found after adjustment for lesion size, bronchus sign, peripheral vs middle third location, and sex. Pneumothorax complicated 1.5% of ssRAB and 1.8% of DT-ENB procedures (P = .86). INTERPRETATION: SSRAB and DT-ENB showed comparable diagnostic yields and safety profiles in this comparative cohort study.

Aging-Related Findings of the Respiratory System in Chest Imaging: Pearls and Pitfalls.

Purpose of Review: The purpose of this review is to describe the main features of the aging chest, studied through different imaging modalities. Recent Findings: Aging-related changes of the respiratory system are inevitable. Therefore, it is mandatory to be familiar with the para-physiological changes that occurs, in order to avoid inappropriate interpretation of radiological findings that put patients at risk of over or undertreatment. Summary: The role of the radiologist is fundamental in evaluating aging-related processes affecting the respiratory system and in distinguishing them from frank diseases.

Advances in Bone Joint Imaging-Metal Artifact Reduction.

Numerous types of metal implants have been introduced in orthopedic surgery and are used in everyday practice. To precisely evaluate the postoperative condition of arthroplasty or trauma surgery, periprosthetic infection, and the loosening of implants, it is important to reduce artifacts induced by metal implants. In this review, we focused on technical advances in metal artifact reduction using digital tomosynthesis, computed tomography, and magnetic resonance imaging. We discussed new developments in diagnostic imaging methods and the continuous introduction of novel technologies to reduce metal artifacts; however, these innovations have not yet completely removed metal artifacts. Different algorithms need to be selected depending on the size, shape, material and implanted body parts of an implant. Future advances in metal artifact reduction algorithms and techniques and the development of new sequences may enable further reductions in metal artifacts even on original images taken previously. Moreover, the combination of different imaging modalities may contribute to further reductions in metal artifacts. Clinicians must constantly update their knowledge and work closely with radiologists to select the best diagnostic imaging method for each metal implant.

Usefulness of digital tomosynthesis in diagnosing cervical ossification of the posterior longitudinal ligament: a comparative study with other imaging modalities.

PURPOSE: The diagnosis and classification of ossification of the posterior longitudinal ligament (OPLL) can be difficult with radiography alone; therefore, computed tomography (CT) is also usually performed. There are many reports on the usefulness of digital tomosynthesis (DTS) for image analysis in orthopedics. This study aimed to compare the accuracy of DTS with radiography and CT for the diagnosis and classification of cervical OPLL (C-OPLL). MATERIALS AND METHODS: We included 31 patients with OPLL and 30 with cervical spondylotic myelopathy. The patients' cervical spine radiography, DTS, and CT images were each evaluated twice by three specialists and three residents. RESULTS: In the intra-observer reliability study, there was one observer with a fair level of kappa values for radiography and DTS among three residents. The kappa values for CT were the best for all observers. In the inter-observer reliability study, the interclass correlation coefficient (ICC) values were high for both diagnosis and classification by specialists at the almost perfect level for all three imaging modalities. On the other hand, the ICC values for both diagnosis and classification for radiography by the residents were lower than those for DTS and CT. CONCLUSIONS: This study revealed that DTS may be an alternative to CT for the diagnosis and classification of C-OPLL by specialists. Caution should be exercised in diagnosing and classifying C-OPLL using radiography and DTS by residents, and the use of CT is recommended.

Does transbronchial lung cryobiopsy improve diagnostic yield of digital tomosynthesis-assisted electromagnetic navigation guided bronchoscopic biopsy of pulmonary nodules? A pilot study.

INTRODUCTION: Bronchoscopic biopsies have limited sensitivity for small, peripheral lung nodules. Electromagnetic navigation guided bronchoscopy (ENB) with fluoroscopic digital tomosynthesis and a 1.1 mm cryoprobe for transbronchial lung cryobiopsy (TBLC) may improve diagnostic yield. We evaluated the diagnostic yield and safety of this approach. METHODS: 42 patients (45 nodules) underwent sequential biopsies by transbronchial needle aspiration (TBNA), then forceps biopsy (FB), and finally TBLC. Demographic data, nodule characteristics, biopsy results, and procedural complications were recorded. RESULTS: Nodules were predominantly solid (n = 35, 78%), without a bronchus sign (n = 30, 67%), and 33% (n = 15) were <2 cm in all dimensions (mean axial: 25.7 ± 15.3 mm, coronal: 21.0 ± 10.1 mm, sagittal 25.5 ± 16.5 mm). TBNA was the most informative biopsy modality (31/45 diagnoses total, five unique, 69% modality diagnostic yield (MDY)) compared to FB (27/45, one unique, 60% MDY) or TBLC (27/45, six unique, 60% MDY). FB contributed four additional diagnoses, improving diagnostic yield to 80% (36/45). TBLC contributed six additional diagnoses for a final diagnostic yield of 93% (42/45). No bleeding that required intervention or pneumothoraxes occurred. In unadjusted logistic regression models, solid nodules had increased odds of obtaining a diagnosis with TBNA (OR: 5.06; 95% CI: 1.14-22.49) and increased axial dimension nodule size had increased odds of obtaining a diagnosis with TBLC (OR: 1.10; 95% CI: 1.02-1.19). CONCLUSION: ENB guided TBLC of lung nodules appears safe and may increase the final diagnostic yield when combined with other modalities. Future studies identifying nodule characteristics and comparing biopsy tools may clarify the most efficacious approach to maximize yield and minimize risk.

Size and vision: Impact of fluoroscopic navigation, digital tomosynthesis, and continuous catheter tip tracking on diagnostic yield of small, bronchus sign negative lung nodules.

INTRODUCTION: Accurate biopsies of lung nodules, including small (<2 cm), bronchus sign negative lesions, remain challenging. Technological advances, however, may improve outcomes. We describe our experience using a novel system combining fluoroscopic navigation with digital tomosynthesis and continuous catheter tip tracking to guide lung nodule biopsies. METHODS: Demographic data, procedural characteristics, and biopsy results from prospectively enrolled patients were collected. RESULTS: 159 nodules (144 patients) were biopsied. Average nodule size was 22.2 ± 15.2 mm (axial), 21.7 ± 13.9 mm (coronal), and 33.2 ± 20.5 mm (sagittal), with 45% (n = 72) <2 cm in all dimensions and 66% (n = 105) without a bronchus sign. Diagnostic yield was 84% (134/159), with malignancy (n = 75, 47%) most common. A diagnosis was obtained in 75% (n = 54/72) of lesions that were <2 cm in all dimensions and 79% (n = 83/105) of bronchus sign negative lesions. Unadjusted generalized mixed-effects logistic regression models showed that nodule size as a categorical variable (>2 cm in any dimension) and as a continuous variable in the coronal dimension, the presence of a bronchus sign, and a concentric radial EBUS view had an increased odds ratio for diagnosis. A concentric radial EBUS view also had an increased OR for diagnosis in a fully adjusted mixed-effects logistic regression model. CONCLUSION: Fluoroscopic navigation with digital tomosynthesis and continuous catheter tip tracking shows an overall improved diagnostic accuracy compared to historical controls, including for small, bronchus sign negative lesions. Future studies clarifying the optimal modality for patients with different nodules will be of importance to provide the most appropriate procedure tailored to each individual lesion's unique characteristics.