Seiichi Nobuyama

Airway measurements in tracheobronchial stenosis using endobronchial ultrasonography during stenting.

Purpose To assess airway measurements, endobronchial ultrasonography (EBUS) and multidetector, row computed tomography (MDCT) images were compared in patients with tracheal stenosis. Methods Airway stenting was performed on 31 patients, 25 malignant and 6 benign. EBUS and MDCT images were compared before intervention to assess the degree of airway narrowing at 212 sites. Of these, 130 sites were considered normal and 82 abnormal. For malignant stenosis, airway measurements were taken at 160 sites including 112 normal and 48 abnormal. For benign stenosis, airway measurements were taken at 52 sites including 18 normal and 34 abnormal. This technique enables the EBUS probe to measure the distal end to the proximal end of the stenosis whereby the inflated balloon size changes according to the degree of stenosis. Results The diameter and length of the stenotic sites measured by EBUS and MDCT were nearly equal in all patients. Significant correlation was seen at all 212 sites (r=0.805, P<0.0001), 130 normal (r=0.758, P<0.0001) and 82 abnormal (r=0.654, P<0.0001). For malignant cases, there was significant correlation in a total of 160 sites (r=0.810, P<0.0001), 112 normal (r=0.782, P<0.0001) and 48 abnormal (r=0.564, P<0.0001). Benign cases showed significant correlations in total 52 sites (r=0.780, P<0.0001), 18 normal (r=0.778, P<0.0001) and 34 abnormal (r=0.731, P<0.0001). Conclusion This EBUS technique was successful in establishing accurate airway measurements for suitable airway stent sizes in interventional procedures, especially in cases with tracheobronchial malacia.

New technique for endobronchial ultrasound-guided transbronchial needle aspiration to improve diagnostic yield.

Background:Although the pooled sensitivity of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) using a convex scanning ultrasound bronchoscope is equivalent to the gold standard of mediastinoscopy, diagnosis cannot be obtained in a small number of patients with poor cellularity. The method described was investigated with the aim of avoiding puncturing the cartilage and enabling reliable tissue harvesting, as this can be expected to improve diagnostic yield. Methods:Outer sheath method (OSM): While pressing the outer sheath (OS) of the puncture needle gently against the bronchial wall, the hyperechoic line appeared on surface of the bronchial wall on EBUS image. Then pulling and pushing the entire bronchoscope, the tip of OS moved to the epithelium above the bronchial cartilage while detecting the best position for puncturing on the EBUS images simultaneously. The bronchoscopist could visualize the cartilage moving longitudinally on EBUS image. The movement of the cartilage was stopped when the tip of the OS was caught in a concavity between 2 rings of cartilage. Group A consisted of 169 patients who underwent EBUS-TBNA before the introduction of OSM, and group B consisted of 169 patients who underwent EBUS-TBNA after the introduction of OSM. These 2 groups were compared with to investigate the usefulness of OSM. Results:Adding this operation enabled a suitable puncture site to be identified, significantly improving diagnostic yield from 92.7% (group A) to 98.2% (group B). Conclusions:This method was regarded as useful for improving diagnostic yield by enabling the selection of a puncture site between rings of cartilage during EBUS-TBNA.

Vibration response imaging in healthy Japanesesubjects

BACKGROUND Vibration response imaging (VRI) records the intensity and distribution of lung sounds during the respiration cycle. Our objective was to analyze VRI findings in healthy Japanese adults. METHODS VRI images of 106 healthy subjects (33.7±9.6 years, 52 male and 54 female), including 67 nonsmokers and 39 asymptomatic smokers, were recorded. The regional intensity of vibrations was assessed using quantitative lung data (QLD), and VRI dynamic images by rater assessment, left and right lung asynchrony (gap index), and regional lung asynchrony (asynchrony score). RESULTS A dominance of total left lung QLD was observed in all subjects, and this phenomenon was more prominent in female subjects. However, there was no significant difference between the total left and total right lung QLD in smokers. Rater assessments showed that 81.1% of all subjects had a normal final assessment. Male subjects had a significantly higher percentage of good or normal assessments for all image scores, except dynamic image scoring. The asynchrony score was significantly higher in female subjects. There were no significant differences in these qualitative assessments between non-smokers and smokers. CONCLUSIONS Although our QLD results were similar to those of a previous report, there were discrepancies between sexes for the qualitative assessments. A significantly higher number of female subjects had abnormal images as assessed by the raters. Furthermore, significantly higher asynchrony scores were observed in female subjects. The VRI variability in sex may be considered normal among the Japanese population. This study is registered with UMIN-CTR under registration number UMIN000002355.

The Correlation between Lung Sound Distribution and Pulmonary Function in COPD Patients

Background Regional lung sound intensity in chronic obstructive pulmonary disease (COPD) patients is influenced by the severity and distribution of emphysema, obstructed peripheral airways, and altered ribcage and diaphragm configurations and movements due to hyperinflation. Changes in the lung sound distribution accompanied by pulmonary function improvements in COPD patients were observed after bronchodilator inhalation. We investigated the association of lung sound distribution with pulmonary functions, and the effects of emphysematous lesions on this association. These studies were designed to acquire the basic knowledge necessary for the application of lung sound analysis in the physiological evaluation of COPD patients. Methods Pulmonary function tests and the percentage of upper- and lower-lung sound intensity (quantitative lung data [QLD]) were evaluated in 47 stable male COPD patients (54 - 82 years of age). In 39 patients, computed tomography taken within 6 months of the study was available and analyzed. Results The ratio of lower QLD to upper QLD showed significant positive correlations with FEV1 %predicted (%FEV1; ρ = 0.45, p<0.005) and MEF50 %predicted (%MEF50; ρ = 0.46, p<0.005). These correlations were not observed in COPD patients with dominant emphysema (% low attenuation area >40%, n = 20) and were stronger in less emphysematous patients (n = 19, %FEV1; ρ = 0.64, p<0.005, %MEF50; ρ = 0.71, p<0.001). Conclusions In COPD patients, the ratio of lower- to upper-lung sound intensities decreased according to the severity of obstructive changes, although emphysematous lesions considerably affected lung sound distribution.

Assessment of Bronchial Obstruction Using Lateral Pressure Measurement during Bronchoscopy

Background: In patients with bronchial obstruction estimating the location of the maximal obstruction is crucial for guiding interventional bronchoscopy. However, flow-volume curves cannot discriminate between the right and left lungs. Objectives: The aim of this study was to physiologically evaluate bronchial obstruction during interventional bronchoscopy. Methods: We prospectively measured lateral airway pressure (Plat) at either side of the obstruction using a double-lumen catheter (pressure-pressure [P-P] curve) simultaneously to assess the degree of bronchial obstruction in 22 patients. The shape of the P-P curve was assessed to confirm the site of maximal obstruction. Results: In the experimental study, Plat was uniform between both bronchi in the normal model. For the unilateral and bilateral obstruction models, a phase shift was only seen for the more obstructed side. In healthy subjects, the angle of the P-P curve was close to 45° and linear in shape. In patients with bronchial obstruction, the angle was much smaller but approached 45° after the bronchoscopic procedure. The degree of bronchial obstruction was significantly correlated with the angle of the P-P curve (r = –0.51, p < 0.01). Dyspnea significantly increased when the airway lumen was obstructed by more than 60% (p < 0.0001), and when the P-P curve appeared loop-shaped (p < 0.01). Conclusions: The shape of the P-P curve could be used to detect the site of maximal obstruction for the optimal positioning of the stent and assess the need for additional procedures in real time in patients with bronchial obstruction.

Endobronchial Ultrasound for Difficult Airway Problems

Radial-type endobronchial ultrasound (EBUS) is useful for a diagnosis based on the depth of invasion of bronchial carcinoma, because it has the ability to analyze the delicate layer structure of the a

Novel use of a disposable curved stent insertion plastic device for silicone stent placement in patients with limited neck extension.

As granulation tissue formation frequently complicates the insertion of metallic tracheobronchial stents in patients with longer life expectancy, the inert silicone tracheobronchial stent remains the treatment of choice for inoperable benign tracheal stenosis. Similarly, the Y silicone stent insertion also plays an important role for refractory malignant stenoses involving the carina and tracheobronchial junction. The classic insertion method of a straight or Y silicone stent requires rigid bronchoscopy under general anesthesia with a hyperextended neck. This is not an option for patients with limited neck extension. We report a novel method of silicone stent insertion using a disposable curved stent insertion plastic device to solve the problem in 2 patients. The new device may have a role in managing patients with central airway obstruction but limited neck extension. As a valuable alternative to conventional rigid bronchoscope, it also adds to the ease of the silicone stent placement.

Comparison of Airway Measurements for Tracheobronchial Stenosis Between Stereoscopic Bronchoscope and MD-CT

Background: Stereoscopic bronchoscopy is a new diagnostic tool to measure the diameter and cross-sectional area of the airway. The stereoscopic bronchoscope, which operates the same as a standard bronchoscope, utilizes 2 lenses to measure the airway using the principles of triangulation. Furthermore, the stereoscopic bronchoscope has the capability to measure the size of the airway during intervention in real-time, including variable stenosis. Materials and Methods: To prospectively compare preoperative stereoscopic and multidetector computed tomography (MD-CT) images to select the appropriate stent size for airway stenosis. Stereoscopic and MD-CT images were then measured to confirm the correct placement of the stent. Results: Airway stenting was performed on 21 consecutive patients of whom, 15 were diagnosed with malignant and 6 with benign diseases. In total, 165 measurements were taken (134 healthy; 31 affected). For the diameter, Bland-Altman plots were used to measure data from 165 matched stereoscopic and MD-CT measurement sites (bias, 0.40±2.86 mm SD; percentage error, 33%), 134 healthy sites (bias, 0.554±2.83 mm SD; percentage error, 34%), and 31 affected sites (bias, 1.20±2.67 mm SD; percentage error, 52%). For the cross-sectional area, matched stereoscopic and MD-CT measurements were analyzed for 65 sites (bias, −10.53±92.85 mm2 SD; percentage error, 89%), 49 healthy sites (bias, −9.88±39.00 mm2 SD; percentage error, 32%), and 16 affected sites (bias, −13.12±48.81 mm2 SD; percentage error, 92%). Conclusion: Stereoscopic bronchoscopy was able to accurately measure the size of the airway during intervention, to assist in selecting the appropriate size of the stent.

Complete tracheal duplication with unilateral atelectasis in an adult.

Duplication of the trachea is an extremely rare condition that has been infrequently reported in the medical literature. We report an adult case with complete tracheal duplication associated with unilateral atelectasis, which was incidentally detected by computed tomography. Tracheal duplication should be considered as a possible cause of severe atelectasis in adults.