Central Airway Diseases Research Articles

Removal of Self-Expandable Metallic Stents: Is It Possible?

Self-expandable metallic stents (SEMS) have become an important component of the management of central airway disease. These stents are not, however, without problems and stent-related complications (SRCs) can be more formidable to treat than the original indication for SEMS placement. As use of SEMS has increased, the number of patients returning to hospital for management of SRCs has similarly risen. A small group of these patients will have, as their only therapeutic option, stent removal Thus far limited experience exists with late stent removal. Stent extraction is difficult and requires expertise in a variety of techniques. A multidisciplinary approach to both SEMS placement and extraction is strongly advocated.

Multi-Detector Row CT of the Central Airway Disease

Multi-detector row CT (MDCT) provides faster speed, longer coverage in conjunction with thin slices, improved spatial resolution, and ability to produce high quality multiplanar and three-dimensional (3D) images. MDCT has revolutionized the non-invasive evaluation of the central airways. Simultaneous display of axial, multiplanar, and 3D images raises precision and accuracy of the radiologic diagnosis of central airway diseases. This article introduces central airway imaging with MDCT emphasizing on the emerging role of multiplanar and 3D reconstruction. (Tuberculosis and Respiratory Diseases 2003, 55:***-***)

Anatomy of Central Airway and Classification of Bronchoscopic Findings of Central Airway Diseases

Anatomy of Central Airway and Classification of Bronchoscopic Findings of Central Airway Diseases

Nonneoplastic lesions of the tracheobronchial wall: radiologic findings with bronchoscopic correlation.

Nonneoplastic diseases of the central airways are uncommon but can be categorized as either focal or diffuse, although there is some overlap. Focal diseases include postintubation stenosis, postinfectious stenosis, posttransplantation stenosis, and various systemic diseases that may involve the airways and lead to focal stenosis (eg, Crohn disease, sarcoidosis, Behçet syndrome). Diffuse diseases of the central airways include Wegener granulomatosis, relapsing polychondritis, tracheobronchopathia osteochondroplastica, amyloidosis, papillomatosis, and rhinoscleroma. Conventional radiography is often the first step in the evaluation of suspected central airway disease and may be adequate in itself to identify the abnormality. However, computed tomography (CT) improves both the detection and characterization of central airway disease. Bronchoscopy remains the primary procedure for the diagnostic work-up of these disease entities. Nevertheless, a thorough radiologic evaluation with radiography and CT may demonstrate specific imaging findings (eg, calcification) that can help narrow the differential diagnosis and aid in the planning of bronchoscopy or therapeutic intervention.

Measuring in situ central airway resistance in patients with laryngotracheal stenosis.

To evaluate a newly developed bronchoscopic technique for the assessment of intratracheal pressures. In situ measurement of central airway resistance in 20 consecutive spontaneously breathing subjects. Thirteen patients had benign glottic or subglottic stenosis. Seven patients without central airway disease served as normal control subjects. A pressure catheter was introduced into the trachea via the working channel. The pressure swing was measured upstream and downstream of the stenosis. Central airflow was monitored simultaneously using a commercial pneumotachograph attached to a mouthpiece. Data acquisition frequency was 500 Hz. Prestenotic and poststenotic inspiratory and expiratory resistances could be calculated and displayed from the raw data off-line. Inspiratory and expiratory resistances measured in mid-trachea or below the stenosis (subglottic) were 0.36 +/- 0.13 and 0.35 +/- 0.13 kPa.s/L for the control subjects (C), 1.11 +/- 0.47 and 0.65 +/- 0.26 kPa.s/L for patients who did not need to be operated on (NOOP), 7.11 +/- 7.19 and 3.35 +/- 2.25 kPa.s/L respectively for those who required surgical correction (OP). Supraglottic inspiratory and expiratory resistances for C were 0.22 +/- 0.09 and 0.25 +/- 0.06 kPa.s/L, for NOOP 0.15 +/- 0.10 and 0.14 +/- 0.11 kPa.s/L, and for OP 0.26 +/- 0.13 and 0.24 +/- 0.07 kPa.s/L respectively. The cut-off point for surgical correction was estimated to be > 2.5 kPa.s/L of inspiratory resistance. Concurrent expiratory values showed a considerable overlap between OP and NOOP. No correlation could be established between local resistance values and dyspnea score. In situ subglottic flow-pressure tracing in spontaneously breathing patients who present with benign obstruction of the upper airways is well tolerated and may help to identify patients who need surgical correction.

Comparison of the Role of CT and Fiberoptic Bronchoscopy in the Diagnosis of Hemoptysis

Backgrounds: To investigate the role of CT as a screening tool and to compare the diagnostic accuracy with that of the fiberoptic bronchoscopy (FOB) in evaluating the causes of hemoptysis. Methods: The retrospective review of plain chest radiograph, CT and FOB was done in 72 patients with hemoptysis. The diagnosis were confirmed by histology (n=33), bacterial culture (n=6), cytology (n=3), serology (n=2), skin test (n= 1), clinical response (n=5), and airway disease mainly by HRCT (n=22). Results: The causes of hemoptysis were shown to be lung cancer (n=29), bronchiectasis (n=19), tuberculosis (n=12), aspergilloma (n=5), invasive aspergillosis (n=l), COPD (n=3) and others (n=3). The sensitivity was 100% and 91,7% by CT and FOB respectively. The diagnostic compatibility was 95.8% and 59.7% by CT and FOB respectively. The diagnostic compatibility in cases with central airway disease was 96.3% and 100 % in CT and FOB. In parenchymal disease, CT and FOB showed 91.3 % and 43.5 % of compatibility, respectively. airway disease, CT and FOB showed 100% and 31.8% compatibility, respectively. That is to say, CT has higher sensitivity and diagnostic compatibility than FOB for identifying the causes of hemoptysis, and is more helpful for patients with hemoptysis from parenchymal or airway disease. FOB had the advantage in obtaining histologic, cytologic and bacteriologic diagnosis with biopsy or washing Conclusion: CT should be used as the screening method before performing FOB for patients with hemoptysis who have normal or nonspecific findings or peripheral airway disease in plain chest radiograph.

Stenting therapy for stenosing airway disease

Stenosing airway disease is classified as intraluminal obstruction, extrinsic compression, and malacia by the anatomical site of the lesion. Stenting therapy is indicated for symptomatic relief of life-threatening dyspnea caused by the last two types. Airway stents are made with metal mesh and/or silicone rubber, and currently more than 20 kinds of stent are available. The metal stent (e.g. Gianturco stent, Wallstent) is easy to insert, may not need general anesthesia, and has wider internal lumen. Because it is very hard to reposition or remove, it is mainly used in malignant airway obstruction. Among many kinds of silicone stent, the Dumon stent is most widely used for benign and malignant airway stenoses, but general anesthesia and rigid bronchoscopy are needed for insertion. It can be removed when the stenosing airway disease subsides completely. In many clinical studies, most patients (85-90%) improved immediately after stenting, and procedure-related mortality is low (< 3%) in experienced centers. Stent displacement, mucus impaction, and granulation tissue formation are potential complications. Stenting is one of many effective therapeutic modalities for stenosing central airway disease. Careful patient selection, experiences, and continuous development of new technology will bring better results.

気管食道科領域における最新の画像診断（ｈｅｌｉｃａｌ ＣＴなども含む） 気管・気管支・肺： とくに３ＤＣＴ，ＭＲＩ

Spiral CT is a new technique that couples continuous X-ray tube rotation with a continuous table feed. It enables us to acquire a wide range of data during a single breath hold. With an uninterrupted volume of data, spiral CT provides high quality three dimensional (3D) images or Multiplanar Reconstruction (MPR) images. 3D images are useful for evaluating central airway diseases. The advantages include the following: (1) 3D images provide information on the poststenotic bronchus, which cannot be observed by bronchoscopy. (2) 3D images can assess the effect of chemotherapy or radiation therapy. (3) 3D images are useful in planning for stenting or resection. (4) 3D images can demonstrate tracheobronchial mucosal irregularity. However, intramural invasion cannot be evaluated by 3D image.In terms of spatial resolution, MRI is slightly inferior to CT. However, contrast resolutionis higher with MRI than with CT.In this paper, we will discuss the value of spiral CT and MRI in evaluating lung cancer, along with their specific advantages and disadvantages.

中枢気道病変の経過観察中に DPB の合併を見た 2 症例

中枢気道病変の経過観察中に DPB の合併を見た 2 症例