Comparison of Virtual Bronchoscopy with Fiberoptic Bronchoscopy Findings in Patients Exposed to Sulfur Mustard Gas

Transcription

1 Comparison of Virtual Bronchoscopy with Fiberoptic Bronchoscopy Findings in Patients Exposed to Sulfur Mustard Gas Poster No.: C-487 Congress: ECR 212 Type: Scientific Exhibit Authors: S. Akhlaghpoor, A. Aziz Ahari; Tehran/IR Keywords: Occupational / Environmental hazards, Drugs / Reactions, Computer Applications-Virtual imaging, Computer ApplicationsDetection, diagnosis, Computer Applications-3D, CT, Thorax, Respiratory system, Lung DOI: /ecr212/C-487 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 11

2 Purpose Fiberoptic Bronchoscopy (FB) is the best modality for evaluation of tracheobronchial endoluminal and mucosal lesions [1]. However, it cannot evaluate the concurrent extra luminal disease or the luminal patency distal to severe stenoses [2]. With current computed tomography (CT) technologies, three dimensional (3D) images of the tracheobronchial tree can be generated. Two basic types of such reconstructed images are available [3, 4]: External rendering or CT bronchography(ctb) in which external features of tracheobronchial tree are reconstructed (Fig. 1). Internal rendering or virtual bronchoscopy (VB) which provides endoscopic like visualization of major airways (Fig 2). In addition to high diagnostic accuracy of VB for detection of airway stenosis, post stenotic regions can also be evaluated [5]. During Iraq-Iran war ( ), some chemical warfare agents including sulfur mustard (SM) gas were used against Iranian people [6-8]. In addition to other pulmonary sequelae, direct damage of SM on the upper airways can lead to scarring, fibrosis, mucociliary malfunction, and subsequently large airway stenosis [9]. With regard to their respiratory complaints, FB is indicated for many of chemical warfare victims to evaluate suspected stenotic lesions. The purpose of current study is the comparison of VB and FB diagnostic abilities in SM exposed patients who are clinically suspected for airway stenosis. Images for this section: Page 2 of 11

3 Fig. 1: An example of CT bronchography (CTB) in a patient with tracheal and bronchial stenosis. Page 3 of 11

4 Fig. 2: An example of virtual bronchoscopy (VB) showing trachea in a patient with tracheal and bronchial stenosis. Page 4 of 11

5 Methods and Materials Fifteen years after chemical attacks, thirty-one patients suspected for tracheobronchial stenosis were selected among patients with documented exposure to SM during IranIraq war. This was a retrospective study on the stored CT data and bronchoscopic findings. Inclusion criteria: unilateral decrease of lung volume and/or signs of localized bronchiectasis in chest x-ray, inspiratory stridor and/or unilateral wheezing, or flow limitation on maximal inspiratory or expiratory flow volume curves in pulmonary function test. Exclusion criteria: previously diagnosis of lung cancer, tuberculosis, or burn injury, history of intubation, intensive care unit admission, or inability to hold breath during CT study. First, CT studies were performed using a Somatom plus 4 CT scanner (Siemens Medical Systems, Erlangen, Germany) with 3-mm collimation (12 kv, 2-25 mas, subsecond 36º rotation and pitch of 1.5). As the scanned segments had 6 to 12 cm length, the acquisition time was about 1-2 sec and the studies were completed in a single breath-hold at full inspiration. Using the kernel 5 algorithm, overlapped axial images were reconstructed at 1.5 mm intervals in a small 2-cm field of view including trachea and proximal airways. In a Syngo MultiModality Workplace (Siemens AG, Erlangen, Germany), VB and CTB images of the major airways were generated. Close to the CT scan time, FB exams were performed by a flexible FB (Olympus BF1T, Tokyo, Japan) via the transnasal route. The estimated grade of stenosis was recorded by a 3-point scale: grade, no stenosis; grade 1, luminal narrowing of < 5%; or grade 2, luminal narrowing of # 5% (Figs. 3-5). Two isolated anatomical locations were evaluated: trachea (from vocal cords to carina) and main bronchi (from carina to the end of each main bronchus before branching). VB or FB results of 4 different patients' bronchi were not available due to technical problems; therefore, the FB-VB comparison was performed for 54 bronchi only (in 27 patients). Finally, diagnostic indices of VB were calculated lesion by lesion and not by patient. Images for this section: Page 5 of 11

6 Fig. 3: A 63 year-old male with tracheobronchial stenosis. (A) CTB image of Grade I tracheal stenosis, (B) VB image of Grade I tracheal stenosis, (C) CTB image of Grade II left bronchial stenosis, (D) VB image of Grade II left bronchial stenosis. Page 6 of 11

7 Fig. 4: Bronchoscopic view of a 39-years-old male showing severe left main bronchial stenosis. Page 7 of 11

8 Fig. 5: A 48 year-old male with Bronchial stenosis. (A) CTB image of Grade I left bronchial stenosis, (B) VB image of Grade I left bronchial stenosis. Page 8 of 11

9 Results The tracheal pathologies seen by FB are shown in Table 1 and the corresponding diagnostic indices of VB are also stated. Table 2 compares the stenotic lesions diagnosed by FB and VB in more detail by cross tabulating their results. Pathology FB VB Sensitivity Specificity Accuracy 9.9% 95% 93.5% Vocal cord 5 (16.1%) problems 4% 96.2% 87.1% Post operative 1 (3.2%) changes 1% 1% 1% Nodule 1 (3.2%) 1% 96.7% 96.8% Mucosal inflammation 8 (26.7%) Stenosis 11 (35.5%) Table 1 - Diagnostic indices of VB for different tracheal pathologies in comparison with FB Stenosis in VB Stenosis in FB Grade 2 Grade 1 Grade Grade 2 4 Grade Grade 1 19 Table 2 - Tracheal stenoses in FB versus VB The bronchial problems diagnosed by FB included 8 cases of stenosis, and one case with a nodule. Twenty patients had bronchial mucosal inflammation in FB. Table 3 compares FB versus VB in detection of bronchial stenosis. VB confirmed the only bronchial nodule shown by FB. Stenosis in VB Page 9 of 11

10 Stenosis in FB Grade 2 Grade 1 Grade Grade Grade Grade 1 45 Table 3 - Bronchial stenoses in FB versus VB The sensitivity, specificity and accuracy of VB in comparison with FB for detection of tracheal stenosis were 9.9%, 95% and 93.5% respectively. For revealing bronchial stenoses, sensitivity, specificity and accuracy indices of VB versus FB were 62.5%, 97.8% and 92.6%, respectively. Together, 13 patients (41.9%) had tracheal or bronchial stenosis diagnosed by either of methods. Comparing with FB, overall sensitivity, specificity and accuracy of VB for revealing tracheobronchial stenosis were shown to be 78.9%. 97.% and 92.6% respectively. Four out of 13 patients with airway stenosis had severe stenoses making the FB evaluation of more distal airways difficult or impossible. Additionally, several SM exposed patients had multiple concurrently affected sites in their respiratory tracts (6 out of 13 patients). VB also revealed two peripheral obstructive lesions beyond the size limits of FB endoscope. VB was unable to show mucosal inflammation. Conclusion This study showed that VB is an accurate and noninvasive way for assessing stenoses, endoluminal nodules, and poststenotic lesions within the central airways of SM exposed victims. Although FB is believed to be the best method for evaluating the airway patency and mucosal lesions, VB may be employed as a complementary study to assess possible post stenotic areas and also for better delineation of long tracheal strictures and their actual length, especially in SM victims who may have multiple coexisting airway stenoses. References Page 1 of 11

11 1. Masanes MJ, Legendre C, Lioret N, Maillard D, Saizy R, Lebeau B. Fiberoptic bronchoscopy for the early diagnosis of subglottal inhalation injury: comparative value in the assessment of prognosis. J Trauma. 1994;36: Aquino SL, Vining DJ. Virtual bronchoscopy. Clin Chest Med. 1999;2:725-73, vii-viii. 3. Finkelstein SE, Summers RM, Nguyen DM, Schrump DS. Virtual bronchoscopy for evaluation of airway disease. Thorac Surg Clin. 24;14: Xiong M, Zhang W, Wang D, Xu J. CT virtual bronchoscopy: imaging method and clinical application. Chin Med J (Engl). 2;113: Boiselle PM, Ernst A. Recent advances in central airway imaging. Chest. 22;121: Abbas F. Report of the specialists appointed by the Secretary-General of the United Nations to investigate allegations by the Islamic Republic of Iran concerning the use of chemical weapons. Arch Belg. 1984;Suppl: Abolghasemi H, Radfar MH, Rambod M, et al. Childhood physical abnormalities following paternal exposure to sulfur mustard gas in Iran: a case-control study. Confl Health.4: Hosseini-khalili A, Haines DD, Modirian E, et al. Mustard gas exposure and carcinogenesis of lung. Mutat Res. 29;678: Rowell M, Kehe K, Balszuweit F, Thiermann H. The chronic effects of sulfur mustard exposure. Toxicology. 29;263:9-11. Personal Information Shahram Akhlaghpoor, MD (Associate professor of Radiology): Tehran University of Medical Sciences Noor Medical Imaging Center Alireza Aziz Ahari, MD (Resident of Radiology): Tehran University of Medical Sciences National Elite Foundation of Iran Page 11 of 11