Conventional and Contrast-enhanced US of the Lung: From Performance to Diagnosis.

In recent years, lung US has evolved from a marginal tool to an integral component of diagnostic chest imaging. Contrast-enhanced US (CEUS) can improve routine gray-scale imaging of the lung and chest, particularly in diagnosis of peripheral lung diseases (PLDs). Although an underused tool in many centers, and despite inherent limitations in evaluation of central lung disease caused by high acoustic impedance between air and soft tissues, lung CEUS has emerged as a valuable tool in diagnosis of PLDs. Owing to the dual arterial supply to the lungs via pulmonary and bronchial (systemic) arteries, different enhancement patterns can be observed at lung CEUS, thereby enabling accurate differential diagnoses in various PLDs. Lung CEUS also assists in identifying patients who may benefit from complementary diagnostic tests, including image-guided percutaneous biopsy. Moreover, lung CEUS-guided percutaneous biopsy has shown feasibility in accessible subpleural lesions, enabling higher histopathologic performance without significantly increasing either imaging time or expenses compared with conventional US. The authors discuss the technique of and basic normal and pathologic findings at conventional lung US, followed by a more detailed discussion of lung CEUS applications, emphasizing specific aspects of pulmonary physiology, basic concepts in lung US enhancement, and the most commonly encountered enhancement patterns of different PLDs. Finally, they discuss the benefits of lung CEUS in planning and guidance of US-guided lung biopsy. ©RSNA, 2024 Supplemental material is available for this article.

Diffusion-weighted Imaging of the Chest: A Primer for Radiologists.

Diffusion-weighted imaging (DWI) is a fundamental sequence not only in neuroimaging but also in oncologic imaging and has emerging applications for MRI evaluation of the chest. DWI can be used in clinical practice to enhance lesion conspicuity, tissue characterization, and treatment response. While the spatial resolution of DWI is in the order of millimeters, changes in diffusion can be measured on the micrometer scale. As such, DWI sequences can provide important functional information to MRI evaluation of the chest but require careful optimization of acquisition parameters, notably selection of b values, application of parallel imaging, fat saturation, and motion correction techniques. Along with assessment of morphologic and other functional features, evaluation of DWI signal attenuation and apparent diffusion coefficient maps can aid in tissue characterization. DWI is a noninvasive noncontrast acquisition with an inherent quantitative nature and excellent reproducibility. The outstanding contrast-to-noise ratio provided by DWI can be used to improve detection of pulmonary, mediastinal, and pleural lesions, to identify the benign nature of complex cysts, to characterize the solid portions of cystic lesions, and to classify chest lesions as benign or malignant. DWI has several advantages over fluorine 18 (18F)-fluorodeoxyglucose PET/CT in the assessment, TNM staging, and treatment monitoring of lung cancer and other thoracic neoplasms with conventional or more recently developed therapies. © RSNA, 2023 Quiz questions for this article are available in the supplemental material. Supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Deep brain stimulation as a palliative treatment for myorhythmia: A case of failure.

BACKGROUND AND PURPOSE: Myorhythmia is a hyperkinetic movement disorder that derives from a disruption of the Guillain-Mollaret triangle, due to an identifiable structural lesion. It is often disabling and with disappointing control under medical treatment. METHODS: Herein, a case of myorhythmia secondary to a vascular insult in the brainstem is reported and an unsuccessful attempt to palliate it with functional neurosurgery. RESULTS: A 67-year-old man displayed a repetitive, rhythmic, slow 2-3 Hz movement, 6 months after suffering a pontomesencephalic hypertensive haematoma. The kinetic phenomenon affected the orbicular and low facial muscles, the neck, the thorax and the upper limbs. Furthermore, he exhibited tremor of the soft palate and pendular nystagmus. On T2-weighted magnetic resonance imaging, hypertrophic degeneration of the inferior olivary complex was seen. He was diagnosed with secondary myorhythmia and multiple pharmacological treatments were tested, but failed. Ultimately, deep brain stimulation with bilateral electrodes placed in the thalamic ventralis intermedius nucleus was offered. Unfortunately, no alleviation of the symptoms was achieved other than mild improvement in involuntary eye movements. CONCLUSIONS: This is the first case to report the use of deep brain stimulation for myorhythmia. Better understanding of the pathophysiology of this condition, and localization of the pacemaker, may allow identification of reliable neurosurgical therapeutic targets.

Role of a portable gamma-camera with optical view for margins assessment of pulmonary nodules resected by radioguided surgery.

PURPOSE: Radioguided occult lesion localization (ROLL) of pulmonary nodules is an alternative to hook-wire. Both required of a histological margin assessment. The activity emerging from the radiotracer allows to obtain an intraoperative scintigraphic image of the surgical specimen by a portable gamma-camera (PGC) fitted with an optical view, which provides information about the localization of the nodule in relation to the margins. The aim of this study was to evaluate the intraoperative use of a PGC for margin assessment of pulmonary nodules. METHODS: ROLL technique was used in 38 nodules (36 pulmonary, 1 chest wall, and 1 pleural nodules). A PGC intraoperative image of the surgical specimen was obtained in 32. Scintigraphic results were compared to the histological assessment. Other factors, such as nodule size, distance from the pleural surface, or distance covered by the needle, were considered as possible factors for non-centered lesions. RESULTS: PGC images showed that the lesion was in contact with the margins in 8/32 cases and centered in 24. In all cases in which the lesion was considered as centered by the PGC, the margins were free of involvement (NPV 100%), although the PPV is low. CONCLUSIONS: The use of a PGC for margin assessment after pulmonary nodule resection is feasible and provides a high NPV in our series. In addition, the short intraoperative time required for its use makes the PGC a useful tool for providing supplementary information to histopathologic results. Further studies from different surgical teams are required for an external validation.

Lung cancer staging: a concise update.

Diagnosis and clinical staging of lung cancer are fundamental to planning therapy. The techniques for clinical staging, i.e anatomic and metabolic imaging, endoscopies and minimally invasive surgical procedures, should be performed sequentially and with an increasing degree of invasiveness. Intraoperative staging, assessing the magnitude of the primary tumour, the involved structures, and the loco-regional lymphatic spread by means of systematic nodal dissection, is essential in order to achieve a complete resection. In resected tumours, pathological staging, with the systematic study of the resected specimens, is the strongest prognostic indicator and is essential to make further decisions on therapy. In the present decade, the guidelines on lung cancer staging of the American College of Chest Physicians and the European Society of Thoracic Surgeons are based on the best available evidence and are widely followed. Recent advances in the classification of the adenocarcinoma of the lung, with the definition of adenocarcinoma in situ, minimally invasive adenocarcinoma and lepidic predominant adenocarcinoma, and the publication of the eighth edition of the tumour, node and metastasis classification of lung cancer, have to be integrated into the staging process. The present review complements the latest guidelines on lung cancer staging by providing an update of all these issues.

Left ventricular noncompaction: imaging findings and diagnostic criteria.

OBJECTIVE: The objectives of this article are to review the imaging findings of left ventricular noncompaction (LVNC) at echocardiography, cardiac MRI, and MDCT; to discuss diagnostic criteria for and the advantages and limitations of these imaging techniques; and to describe pitfalls that can lead to misinterpretation of findings of LVNC. CONCLUSION: LVNC is a cardiac disease of emerging importance, and imaging has a key role in its diagnosis. Accordingly, radiologists should be familiar with LVNC imaging findings to realize an accurate diagnosis.

Imaging of chronic thromboembolic pulmonary hypertension before, during and after balloon pulmonary angioplasty.

Balloon pulmonary angioplasty (BPA) has recently been elevated as a class I recommendation for the treatment of inoperable or residual chronic thromboembolic pulmonary hypertension (CTEPH). Proper patient selection, procedural safety, and post-procedural evaluation are crucial in the management of these patients, with imaging work-up playing a pivotal role. Understanding the diagnostic and therapeutic imaging algorithms of CTEPH, the imaging features of patients amenable to BPA, all imaging findings observed during and immediately after the procedure and the changes observed during the follow-up is crucial for all interventional radiologists involved in the care of patients with CTEPH. This article illustrates the imaging work-up of patients with CTEPH amenable to BPA, the imaging findings observed before, during and after BPA, and provides a detailed description of all imaging modalities available for CTEPH evaluation.

Biological equivalent dose is associated with radiological toxicity after lung stereotactic ablative radiation therapy.

INTRODUCTION: Stereotactic ablative radiation therapy (SABR) is the standard of care for inoperable early-stage non-small-cell lung cancer. Although the probability of grade ≥ II toxicities is low, many patients present radiological subclinical toxicities usually associated with long-term patient management challenges. We evaluated radiological changes and correlated them with the received Biological Equivalent Dose (BED). METHODS: We retrospectively analyzed chest CT scans of 102 patients treated with SABR. An experienced radiologist evaluated the radiation-related changes 6 months and 2 years after SABR. The presence of consolidation, ground-glass opacities, organizing pneumonia pattern, atelectasis and the extent of affected lung were recorded. Dose-volume histograms of the lung healthy tissue were transformed to BED. Clinical parameters such as age, smoking habits, and previous pathologies were registered and correlations between BED and radiological toxicities were drawn. RESULTS: We observed a positive and statistically significant correlation between lung BED over 300 Gy and the presence of organizing pneumonia pattern, the degree of lung affectation and the 2-year prevalence and/or increase of these radiological changes. Radiological changes in patients receiving BED > 300 Gy to a healthy lung volume ≥ 30 cc increased or remained in the 2 years follow-up scan. We found no correlation between radiological changes and the analyzed clinical parameters. CONCLUSIONS: There seems to be a clear correlation between BEDs higher than 300 Gy and radiological changes both short and long term. If confirmed in an independent patient cohort, these findings could lead to the first radiotherapy dose constraints for grade I pulmonary toxicity.

The use of lung ultrasound in COVID-19.

This review article addresses the role of lung ultrasound in patients with coronavirus disease 2019 (COVID-19) for diagnosis and disease management. As a simple imaging procedure, lung ultrasound contributes to the early identification of patients with clinical conditions suggestive of COVID-19, supports decisions about hospital admission and informs therapeutic strategy. It can be performed in various clinical settings (primary care facilities, emergency departments, hospital wards, intensive care units), but also in outpatient settings using portable devices. The article describes typical lung ultrasound findings for COVID-19 pneumonia (interstitial pattern, pleural abnormalities and consolidations), as one component of COVID-19 diagnostic workup that otherwise includes clinical and laboratory evaluation. Advantages and limitations of lung ultrasound use in COVID-19 are described, along with equipment requirements and training needs. To infer on the use of lung ultrasound in different regions, a literature search was performed using key words "COVID-19", "lung ultrasound" and "imaging". Lung ultrasound is a noninvasive, rapid and reproducible procedure; can be performed at the point of care; requires simple sterilisation; and involves non-ionising radiation, allowing repeated exams on the same patient, with special benefit in children and pregnant women. However, physical proximity between the patient and the ultrasound operator is a limitation in the current pandemic context, emphasising the need to implement specific infection prevention and control measures. Availability of qualified staff adequately trained to perform lung ultrasound remains a major barrier to lung ultrasound utilisation. Training, advocacy and awareness rising can help build up capacities of local providers to facilitate lung ultrasound use for COVID-19 management, in particular in low- and middle-income countries.

Integral mediastinal staging in patients with NON-SMALL cell lung cancer and risk factors for occult N2 disease.

BACKGROUND: In patients with non-small cell lung cancer (NSCLC), the presence of abnormal hiliar lymph nodes (clinical N1; cN1), central tumor location and/or tumor size (diameter >3 cm) increases the risk of occult mediastinal metastasis (OMM). This study investigates prospectively the diagnostic value of an integral mediastinal staging (IMS) strategy that combines EndoBronchial Ultrasound-TransBronchial Needle Aspiration (EBUS-TBNA) and Video-Assisted Mediastinoscopy (VAM) in patients with NSCLC at risk of OMM. METHODS: Patients with NSCLC and radiologically normal mediastinum assessed non-invasively by positron emission tomography and computed tomography of the chest (PET-CT), and OMM risk factors (cN1, central tumor and/or >3 cm) underwent EBUS-TBNA followed by VAM if the former was negative. Those with negative IMS underwent resection surgery of the tumor. RESULTS: EBUS-TBNA identified OMM in 2 out of the 49 patients evaluated (4%) and VAM in 1 of the 47 patients with negative EBUS (2%). Two patients with a negative IMS had OMM at surgery. Overall, the prevalence of OMM was 10%. EBUS-TBNA has a sensitivity of 40%, a negative predictive value (NPV) of 93.6%, and negative likelihood ratio of 0.60 (95%CI:0.30-1.16). The risk of not diagnosing OMM after EBUS was 6% and after IMS was 4.4%. CONCLUSION: Integral mediastinal staging in patients with NSCLC and clinical risk factors for OMM, does not seem to provide added diagnostic value to that of EBUS-TBNA, except perhaps in patients with cN1 disease who deserve further research.

Preoperative localization of lung nodules: a comparative analysis of hookwire and radio-guided procedures.

Background: Histological diagnosis of pulmonary nodules requires surgical resection on many occasions. There are multiple localization strategies each with their own benefits and complications. The objective of this study is to compare preoperative lung nodule localization with hookwire and radiotracer injection (radioguided occult lesion localization, ROLL). To compare results, complications, and volume of the sample resected with both techniques. Methods: Patients undergoing resection of pulmonary nodules with video-assisted thoracoscopy and pre-surgical localization with hookwire or ROLL were studied. Eighty-eight pulmonary nodules were resected in 76 patients: 52 with a hook wire and 36 with a radiotracer. The localization rate, the shortest distance between the nodule and the pleura, the intrapulmonary distance of the locator, the complications, the volume of the resection piece, and the histological result were all assessed. In addition, the factors that influence the volume of the surgical piece were analyzed. Results: All the nodules were resected with both techniques. The intrapulmonary path of the locator is longer for the ROLL group (23.91 vs. 16.28 mm; P=0.04), with no differences in the distance from the nodule to the pleura. The rate of pneumothorax was significantly higher after the placement of a hook wire (69.2% vs. 24.2%; P<0.0001), while there were no differences in the presence of hemorrhage. The volume of the pieces resected using ROLL was more minor than with hookwire, although not statistically significant (20.19 vs. 34.26 cc; P=0.07). Conclusions: Preoperative localization with the ROLL technique is safer than the placement of hookwire. In addition, the ROLL technique shows a tendency to obtain a smaller volume of resected tissue since the marking is not affected by the intrapulmonary route used during marker placement. ROLL technique allows to locate lung nodules with fewer complications than hookwire and probably gets smaller resection samples.

A Pilot Study to Evaluate Early Predictive Value of Thorax Perfusion-CT in Advanced NSCLC.

BACKGROUND: The role of perfusion computed tomography (pCT) in detecting changes in tumor vascularization as part of a response to antiangiogenic therapy in non-small cell lung cancer (NSCLC) remains unclear. METHODS: In this prospective pilot study (IMPACT trial, NCT02316327), we aimed to determine the ability of pCT to detect early changes in blood flow (BF), blood volume (BV), and permeability (PMB), and to explore whether these changes could predict the response at day +42 in patients with advanced, treatment-naive, non-squamous NSCLC treated with cisplatin and gemcitabine plus bevacizumab. RESULTS: All of the perfusion parameters showed a consistent decrease during the course of treatment. The BV difference between baseline and early assessment was significant (p = 0.013), whereas all perfusion parameters showed significant differences between baseline and day +42 (p = 0.003, p = 0.049, and p = 0.002, respectively). Among the 16 patients evaluable for efficacy, a significant decline in BV at day +7 from baseline was observed in tumors with no response (p = 0.0418). CONCLUSIONS: Our results confirm that pCT can capture early changes in tumor vasculature. A substantial early decline of BV from baseline might identify tumors less likely responsive to antiangiogenic-drugs.

Image-guided percutaneous ablation for the treatment of lung malignancies: current state of the art.

Image-guided percutaneous lung ablation has proven to be a valid treatment alternative in patients with early-stage non-small cell lung carcinoma or oligometastatic lung disease. Available ablative modalities include radiofrequency ablation, microwave ablation, and cryoablation. Currently, there are no sufficiently representative studies to determine significant differences between the results of these techniques. However, a common feature among them is their excellent tolerance with very few complications. For optimal treatment, radiologists must carefully select the patients to be treated, perform a refined ablative technique, and have a detailed knowledge of the radiological features following lung ablation. Although no randomized studies comparing image-guided percutaneous lung ablation with surgery or stereotactic radiation therapy are available, the current literature demonstrates equivalent survival rates. This review will discuss image-guided percutaneous lung ablation features, including available modalities, approved indications, possible complications, published results, and future applications.

How do we Classify a Central Tumor? Results of a Multidisciplinary Survey from the SEPAR Thoracic Oncology Area. / ¿Cómo clasificamos un tumor central? Resultados de una encuesta multidisciplinaria propuesta desde el área de Oncología Torácica de SEPAR.

INTRODUCTION: In patients with non-small cell lung cancer (NSCLC) and normal mediastinal imaging tests, centrally located tumors have greater occult mediastinal involvement. Clinical guidelines, therefore, recommend invasive mediastinal staging in this situation. However, definitions of centrality in the different guidelines are inconsistent. The SEPAR Thoracic Oncology area aimed to evaluate the degree of familiarity with various concepts related to tumor site among professionals who see patients with NSCLC in Spain. METHODS: A questionnaire was distributed to members of Spanish medical societies involved in the management of NSCLC, structured according to the 3 aspects to be evaluated: 1) uniformity in the definition of central tumor location; 2) uniformity in the classification of lesions that extend beyond dividing lines; and 3) ability to delineate lesions in the absence of dividing lines. RESULTS: A total of 430 participants responded. The most voted definition of centrality was «lesions in contact with hilar structures¼ (49.7%). The lines most often chosen to delimit the hemitorax were concentric hilar lines (89%). Most participants (92.8%) classified tumors according to the side of the dividing line that contained most of their volume. Overall, 78.6% were able to correctly classify a central lesion in the absence of dividing lines. CONCLUSIONS: In our survey, the most widely accepted definition of centrality is not one of the proposals specified in the clinical guidelines. The results reflect wide variability in the classification of tumor lesions.

Limited Liver or Lung Colorectal Cancer Metastases. Systemic Treatment, Surgery, Ablation or SBRT.

The prognosis for oligometastatic colorectal cancer has improved in recent years, mostly because of recent advances in new techniques and approaches to the treatment of oligometastases, including new surgical procedures, better systemic treatments, percutaneous ablation, and stereotactic body radiation therapy (SBRT). There are several factors to consider when deciding on the better approach for each patient: tumor factors (metachronous or synchronous metastases, RAS mutation, BRAF mutation, disease-free interval, size and number of metastases), patient factors (age, frailty, comorbidities, patient preferences), and physicians' factors (local expertise). These advances have presented major challenges and opportunities for oncologic multidisciplinary teams to treat patients with limited liver and lung metastases from colorectal cancer with a curative intention. In this review, we describe the different treatment options in patients with limited liver and lung metastases from colorectal cancer, and the possible combination of three approaches: systemic treatment, surgery, and local ablative treatments.

Pathological response to neoadjuvant therapy with chemotherapy vs chemoradiotherapy in stage III NSCLC-contribution of IASLC recommendations.

BACKGROUND: Neoadjuvant treatment (NT) with chemotherapy (Ch) is a standard option for resectable stage III (N2) NSCLC. Several studies have suggested benefits with the addition of radiotherapy (RT) to NT Ch. The International Association for the Study of Lung Cancer (IASLC) published recommendations for the pathological response (PHR) of NSCLC resection specimens after NT. AIM: To contribute to the IASLC recommendations showing our results of PHR to NT Ch vs NT chemoradiotherapy (ChRT). METHODS: We analyzed 67 consecutive patients with resectable stage III NSCLC with positive mediastinal nodes treated with surgery after NT Ch or NT ChRT between 2013 and 2020. After NT, all patients were evaluated for radiological response (RR) according to Response Evaluation Criteria in Solid Tumours criteria and evaluated for surgery by a specialized group of thoracic surgeons. All histological samples were examined by the same two pathologists. PHR was evaluated by the percentage of viable cells in the tumor and the resected lymph nodes. RESULTS: Forty patients underwent NT ChRT and 27 NT Ch. Fifty-six (83.6%) patients underwent surgery (35 ChRT and 21 Ch). The median time from ChRT to surgery was 6 wk (3-19) and 8 wk (3-21) for Ch patients. We observed significant differences in RR, with disease progression in 2.5% and 14.8% of patients with ChRT and Ch, respectively, and partial response in 62.5% ChRT vs 29.6% Ch (P = 0.025). In PHR we observed ≤ 10% viable cells in the tumor in 19 (54.4%) and 2 cases (9.5%), and in the resected lymph nodes (RLN) 30 (85.7%) and 7 (33.3%) in ChRT and Ch, respectively (P = 0.001). Downstaging was greater in the ChRT compared to the Ch group (80% vs 33.3%; P = 0.002). In the univariate analysis, NT ChRT had a significant impact on partial RR [odds ratio (OR) 12.5; 95% confidence interval (CI): 1.21 - 128.61; P = 0.034], a decreased risk of persistence of cancer cells in the tumor and RLN and an 87.5% increased probability for achieving downstaging (OR 8; 95%CI: 2.34-27.32; P = 0.001). CONCLUSION: We found significant benefits in RR and PHR by adding RT to Ch as NT. A longer follow-up is necessary to assess the impact on clinical outcomes.

EBUS-TBNA Cytological Samples for Comprehensive Molecular Testing in Non-Small Cell Lung Cancer.

Clinical guidelines promote the identification of several targetable biomarkers to drive treatment decisions in advanced non-small cell lung cancer (NSCLC), but half of all patients do not have a viable biopsy. Specimens from endobronchial-ultrasound transbronchial needle aspiration (EBUS-TBNA) are an alternative source of material for the initial diagnosis of NSCLC, however their usefulness for a complete molecular characterization remains controversial. EBUS-TBNA samples were prospectively tested for several biomarkers by next-generation sequencing (NGS), nCounter, and immunohistochemistry (PD-L1). The primary objectives were to assess the sensitivity of EBUS-TBNA samples for a comprehensive molecular characterization and to compare its performance to the reference standard of biopsy samples. Seventy-two EBUS-TBNA procedures were performed, and 42 NSCLC patients were diagnosed. Among all cytological samples, 92.9% were successfully genotyped by NGS, 95.2% by nCounter, and 100% by immunohistochemistry. There were 29 paired biopsy samples; 79.3% samples had enough tumor material for genomic genotyping, and 96.6% for PD-L1 immunohistochemistry. A good concordance was found between both sources of material: 88.9% for PD-L1, 100% for NGS and nCounter. EBUS-TBNA is a feasible alternative source of material for NSCLC genotyping and allows the identification of patient candidates for personalized therapies with high concordance when compared with biopsy.

Usefulness of Two Independent DNA and RNA Tissue-Based Multiplex Assays for the Routine Care of Advanced NSCLC Patients.

Personalized medicine is nowadays a paradigm in lung cancer management, offering important benefits to patients. This study aimed to test the feasibility and utility of embedding two multiplexed genomic platforms as the routine workup of advanced non-squamous non-small cell lung cancer (NSCLC) patients. Two parallel multiplexed approaches were performed based on DNA sequencing and direct digital detection of RNA with nCounter® technology to evaluate gene mutations and fusions. The results were used to guide genotype-directed therapies and patient outcomes were collected. A total of 224 advanced non-squamous NSCLC patients were prospectively included in the study. Overall, 85% of samples were successfully characterized at DNA and RNA levels and oncogenic drivers were found in 68% of patients, with KRAS, EGFR, METΔex14, BRAF, and ALK being the most frequent (31%, 19%, 5%, 4%, and 4%, respectively). Among all patients with complete genotyping results and follow-up data (n = 156), the median overall survival (OS) was 1.90 years (confidence interval (CI) 95% 1.69-2.10) for individuals harbouring an actionable driver treated with a matched therapy, compared with 0.59 years (CI 95% 0.39-0.79) in those not eligible for any targeted therapy and 0.61 years (CI 95% 0.12-1.10) in patients with no drivers identified (p < 0.001). Integrating DNA and RNA multiplexing technologies into the routine molecular testing of advanced NSCLC patients is feasible and useful and highlights the necessity of widespread integrating comprehensive molecular diagnosis into lung cancer care.

[Usefulness of radial endobronchial ultrasound-guided transbronchial needle aspiration for the diagnosis of mediastinal lymph nodes]. / Utilidad de la punción aspirativa transbronquial guiada con ultrasonografía endobronquial (USEB) radial para el diagnóstico de adenopatías mediastínicas.

INTRODUCTION: Transbronchial needle aspiration (TBNA) is a bronchoscopic technique that has been shown to be useful for sampling enlarged mediastinal lymph nodes. The yield of this technique can be increased by using endobronchial ultrasound (EBUS) to guide needle placement. The aim of the present study was to compare the yield of radial EBUS-guided TBNA to that of conventional TBNA in the analysis of mediastinal lymph nodes. PATIENTS AND METHODS: All patients undergoing either EBUS-guided or conventional TBNA for the diagnosis of mediastinal lymph nodes between January 2006 and May 2007 were studied consecutively. Histology results were used as a reference standard in the patients treated surgically. In cases in which surgery was not indicated, the results of cytology or of clinical follow-up of at least 6 months duration were used. RESULTS: TBNA was performed in 117 patients, and a total of 143 lymph nodes were punctured (mean shortest [SD] diameter, 17.9 [8]mm). The samples obtained were diagnostic in 58 patients (49.6%) and in 70 lymph nodes (49.0%). For paratracheal and hilar stations, the yield of radial EBUS-guided TBNA was superior to that of conventional TBNA (59.2% compared to 34.1%, P=.02). CONCLUSIONS: Radial EBUS guidance increases the diagnostic yield of TBNA in paratracheal and hilar lymph node stations.