Comparative Evaluation of Super High-Resolution CT Scan and Virtual Bronchoscopy for the Detection of Tracheobronchial Malignancies: Discussion
As with SHR-CT scans and VBs, additional obstructive lesions were appreciated by CT scans that were not visualized by FB. Three of six of these obstructive lesions (50%) were confirmed to be positive by histologic evaluation. The locations of these lesions were in the left lower lobe (two lesions) and the right lower lobe (one lesion) [Fig 3, bottom right, F],
Rapid technological advances in image processing have permitted the simulation of endoscopic procedures using sophisticated, but relatively inexpensive, computer workstations. In thoracic imaging, the trachea, mainstem bronchi, and many of the segmental bronchi can be readily visualized by new diagnostic modalities. Although standard methodologies are readily available, their limitations may lead to an inaccurate characterization of airway pathology.
Preliminary studies reported by Finkelstein et al, Fleiter et al, Liewald et al, Rapp-Bernhardt and colleagues, and Seemann et al have demonstrated the feasibility and utility of VB in patients with primary or metastatic cancers involving the lungs and mediastinum (Table 2). However, limited information is available comparing SHR-CT scanning to other imaging modalities in this clinical context. Our current study was performed to directly compare in a prospective manner the diagnostic potentials of standard CT scanning, SHR-CT scanning, and VB relative to FB for the detection of tracheobronchial neoplasms. other
We observed that SHR-CT scanning and VB are excellent imaging modalities with sensitivities of 100% for the detection of obstructive stenotic lesions. Furthermore, these modalities are highly effective for assessing airway patency distal to high-grade stenoses and for identifying lesions in subsegmental bronchi. Therefore, SHR-CT scanning and VB had overall sensitivities of 83% for the detection of any abnormality in the tracheobronchial tree. However, these techniques are presently not effective for the detection of subtle mucosal abnormalities such as erythema or early sessile lesions. SHR-CT scans and VB may not be appropriate for identifying premalignant lesions in the respiratory tract. Nevertheless, technologies such as fiberoptic confocal microscopy, optical CT scanning, high-resolution ultrasonography, and positron emission tomography may complement the detection of these lesions in the near future.
Table 2—Summary of Literature for VB Detection of Tracheobronchial Malignancies
|Fleiter et al/1997||20||Thoracic malignancies||Images successfully created in 19/20 patients; high-grade stenoses accurately detected; discrete malignant infiltration and extraluminal compression not visualized in five patients||Not reported||Not reported|
|Liewald et al/1998||30||Lung cancer||Thirteen obstructive lesions seen equally well by VB and FB; VB visualized anatomy beyond high-grade stenosis in two patients; mucosal lesions not visualized||Not reported||Not reported|
|Rapp-Bernhardt et al/1998||21||Esophageal carcinoma||No statistically significant difference in the location or grading of stenoses comparing VB with FB||Not reported||Not reported|
|Rapp-Bernhardt et al/2000||18||Bronchogenic
|CT scan and VB used to evaluate tracheobronchial stenoses that had been detected by FB||CT scan, 93%; VB, 94%||CT scan, 100%; VB, 99.7%|
|Finkelstein et al/2002||20||Thoracic malignancies||Images successfully created in all patients; high-grade stenosis and endoluminal lesions accurately detected; difficulty detecting subtle mucosal lesions||VB, 82%||VB, 100%|