European Journal of Cardiovascular Medicine

Accurate assessment of airway pathology is vital in the diagnosis, staging, therapeutic planning, and follow-up of patients with tracheobronchial lesions. Traditionally, flexible fiberoptic bronchoscopy (FOB) has served as the gold standard for direct visualization of the tracheobronchial tree, allowing not only anatomic assessment but also biopsy and therapeutic interventions. However, FOB is an invasive and may lead to patient discomfort, bleeding, respiratory compromise, or procedural complications, particularly in critically ill or uncooperative individuals (1).

With the advent of multi-detector computed tomography (MDCT), thoracic imaging has undergone significant advancement. MDCT enables high-resolution data acquisition, which, through sophisticated post-processing techniques, can be reconstructed into virtual bronchoscopy (VB), multiplanar reformatted (MPR), and minimal-intensity projection (minIP) images. These tools offer a noninvasive means to evaluate the tracheobronchial tree and surrounding structures, often overcoming limitations posed by FOB, such as inability to traverse high-grade obstructions or assess extraluminal extension (2,3).

Introduced in 1993, virtual bronchoscopy uses MDCT-derived volumetric datasets to generate three-dimensional, endoluminal views that simulate those of conventional bronchoscopy. Several studies have demonstrated that VB can reliably delineate tracheobronchial stenoses, determine the extent of airway narrowing, visualize distal airways beyond obstructions, and identify adjacent mediastinal lymphadenopathy (4–7). VB has also been shown to aid in pre-procedural planning, such as stent placement or lymph node biopsy (8–10). Nevertheless, unlike FOB, VB does not permit mucosal inspection or tissue sampling, limiting its role as a standalone diagnostic modality (11,12).

Moreover, although VB has gained clinical acceptance, only a limited number of studies have directly compared its diagnostic performance with FOB, particularly in the follow-up of large airway stenosis (13,14). Given these gaps, the present study was designed to compare MDCT-based virtual bronchoscopy with conventional fiberoptic bronchoscopy in terms of their ability to detect airway lesions, estimate the degree and length of stenosis, assess segmental involvement, visualize distal airways, and evaluate overall diagnostic confidence.

This comparative evaluation aims to asssess the diagnostic value of MDCT-derived reconstructions and determine their potential role as adjuncts or alternatives to conventional bronchoscopy in clinical practice, particularly in patients for whom invasive procedures pose additional risks.

This study was conducted in the Department of Radiodiagnosis in collaboration with the Department of Pulmonary Medicine at , a tertiary care center. The sample size was determined based on previously reported diagnostic performance of MDCT virtual bronchoscopy in airway lesion assessment. Assuming an expected sensitivity and specificity of around 85–90% and aiming for sufficient statistical validity, the final sample size was calculated 50 patients.

Fifty adult patients clinically suspected of having tracheobronchial pathology were enrolled based on symptoms such as persistent cough, hemoptysis, stridor, wheezing, or unexplained dyspnea. All patients were referred for both contrast-enhanced MDCT chest imaging and  fiberoptic bronchoscopy (FOB) for evaluation. Inclusion criteria were patients aged 18 years and above who could undergo both procedures. Patients were excluded if they had contraindications to bronchoscopy such as severe coagulopathy or unstable cardiopulmonary status, or if their CT images were of suboptimal quality due to motion artifacts or incomplete scanning.

 All patients underwent contrast-enhanced MDCT of the thorax using a 64-slice multidetector CT scanner. Scanning was performed in the supine position during a single breath-hold with parameters set at 120 kVp, 150–250 mAs, pitch 1–1.2, and slice thickness ranging from 0.6 to 1.25 mm. Images were reconstructed using both soft tissue and lung algorithms. Post-processing was performed on a dedicated workstation to generate multiplanar reformatted (MPR) images, minimal intensity projection (minIP) views, and virtual bronchoscopy (VB) using volume rendering techniques.

Fiberoptic bronchoscopy was performed within 48 to 72 hours of MDCT imaging by an experienced pulmonologist using a standard flexible bronchoscope under local anesthesia, with or without mild sedation depending on clinical need. Observations regarding the presence, location, extent, and degree of airway narrowing; mucosal lesions; and distal airway patency were systematically recorded and served as the reference standard for comparison.

The diagnostic performance of MDCT-derived techniques  was evaluated against fiberoptic bronchoscopy in terms of lesion detection, measurement of the degree and length of stenosis, assessment of segmental involvement, visualization of airways distal to obstructions, and diagnostic confidence. The collected data were analyzed using IBM SPSS Statistics software version [25]. Continuous variables were expressed as mean ± standard deviation (SD), while categorical variables were summarized as frequencies and percentages. Diagnostic parameters such as sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy were calculated. Agreement between MDCT and bronchoscopy findings was assessed using Cohen’s kappa coefficient. A p-value less than 0.05 was considered statistically significant.

A total of 50 patients were enrolled in the study to compare the diagnostic utility of multi-detector computed tomography (MDCT) virtual tracheo-bronchoscopy (VB) with conventional fiberoptic bronchoscopy (FOB) in the assessment of airway lesions. The demographic profile of the study population is summarized in Table 1. The mean age of the patients was 52.6 ± 14.2 years, with an age range of 22 to 79 years. The median age was 54 years, with an interquartile range (IQR) of 41–63 years. Among the 50 patients, 34 (68.0%) were male and 16 (32.0%) were female.

Table 1: Comparison of Lesion Detection and Diagnostic Parameters between MDCT-VB and Fiberoptic Bronchoscopy (FOB) (n = 50)

Lesion detection was high in both MDCT-VB and FOB modalities. MDCT-VB successfully identified airway lesions in 45 out of 50 patients (90.0%), while FOB detected lesions in 47 patients (94.0%). The difference in detection rates between the two modalities was not statistically significant (p = 0.456, Chi-square test), indicating comparable efficacy in identifying airway pathology.

Regarding the quantitative assessment of airway narrowing, the mean degree of stenosis estimated on MDCT-VB was 71.2 ± 10.4%, while FOB reported a slightly higher mean value of 73.5 ± 9.8%. However, this difference did not reach statistical significance (p = 0.328, t-test). Similarly, the average length of the stenotic airway segment measured using MDCT-VB was 19.6 ± 4.2 mm, compared to 18.9 ± 3.9 mm with FOB, again showing no significant difference (p = 0.482, t-test). These findings suggest that MDCT-VB can reliably approximate the anatomical severity of airway narrowing comparable to FOB.

One of the notable advantages of MDCT-VB in this study was its superior ability to visualize distal airway segments beyond the site of obstruction. MDCT-VB successfully depicted the distal airway in 43 patients (86.0%) as opposed to FOB, which could do so in only 35 patients (70.0%). This difference was statistically significant (p = 0.027, Chi-square test), highlighting the noninvasive benefit of MDCT-VB in evaluating airway regions inaccessible to FOB due to high-grade stenosis or tight luminal narrowing(Table 2).

Table 2: Diagnostic Performance of MDCT Virtual Bronchoscopy (VB) Compared to Fiberoptic Bronchoscopy (FOB) (n = 50)

The diagnostic performance of MDCT-VB was further evaluated using fiberoptic bronchoscopy as the reference standard. The sensitivity of MDCT-VB for detecting airway lesions was 95.7%, while the specificity was 60.0%. The positive predictive value (PPV) and negative predictive value (NPV) were calculated to be 97.8% and 42.9%, respectively. The overall diagnostic accuracy of MDCT-VB was found to be 92.0%. Agreement analysis using Cohen’s Kappa statistic yielded a value of 0.73, which indicates substantial agreement between MDCT-VB and FOB in lesion detection(Table 3).

Furthermore, receiver operating characteristic (ROC) curve analysis was performed to assess the discriminative ability of MDCT-VB in comparison to FOB. The area under the ROC curve (AUC) for MDCT-VB was 0.93, indicating excellent diagnostic performance and high reliability in distinguishing between patients with and without airway lesions (Figure 1).

Figure 1: ROC Curve

Figure 2: From right to left — (A) Fiberoptic bronchoscopy, (B) Coronal CT image, and (C) Virtual bronchoscopy image showing tracheal stenosis.

This study aimed to assess the diagnostic performance of multi-detector computed tomography (MDCT) virtual bronchoscopy (VB) in comparison to conventional fiberoptic bronchoscopy (FOB) in patients with suspected tracheobronchial lesions. Our results demonstrate that VB is a highly effective and reliable non-invasive tool with diagnostic performance closely approximating that of FOB.

In the present study, MDCT-VB detected airway lesions in 45 of 50 patients (90.0%), whereas FOB identified lesions in 47 of 50 patients (94.0%). The difference was not statistically significant (p = 0.456), suggesting that VB has comparable lesion detection capability to FOB in most clinical settings. Similar findings were reported by Hafez et al., who observed that VB had a high sensitivity in identifying endoluminal lesions and was particularly useful in cases where FOB was limited due to obstruction or patient intolerance (15).

Quantitative assessment of airway stenosis showed a mean degree of narrowing of 71.2 ± 10.4% with VB, compared to 73.5 ± 9.8% with FOB (p = 0.328). The mean stenotic segment length was also comparable (VB: 19.6 ± 4.2 mm vs. FOB: 18.9 ± 3.9 mm; p = 0.482). These results align with those of T. Fleiter et al. (16), who reported that VB and FOB provided equivalent measurements of high-grade stenoses in lung cancer patients. VB, therefore, appears to be reliable in estimating the anatomical severity of airway narrowing.

One of the key advantages of VB observed in our study was its ability to visualize airways beyond stenotic segments. VB allowed distal airway evaluation in 86.0% of cases compared to only 70.0% by FOB (p = 0.027). This finding is consistent with several published studies. Hafez et al. (15)reported that visualization distal to obstruction was possible in 61.8% of cases using VB, compared to 32.4% with FOB. Similarly, Fleiter et al. (16) noted that VB enabled distal airway visualization in 25% of cases where FOB failed to advance beyond the stenosis. This enhanced visualization capability can be vital for planning therapeutic interventions such as stenting, resection, or ablative therapy.

In terms of diagnostic performance, VB demonstrated a sensitivity of 95.7%, specificity of 60.0%, and overall diagnostic accuracy of 92.0% in our study. The positive predictive value (PPV) was high at 97.8%, while the negative predictive value (NPV) was relatively low at 42.9%. The substantial agreement between VB and FOB was reflected in a Cohen’s Kappa coefficient of 0.73. These figures are comparable to those reported by previous researchers. For example, in a study by M. Beker Acay et al. (17), VB missed several abnormalities—especially mucosal lesions—and had a lower sensitivity compared to FOB. Notably, in our study, all 6 cases with mucosal changes and 3 with small endoluminal growths were missed by VB, which underlines the limitation of VB in detecting superficial mucosal pathology.

This shortcoming is well-documented. Both Acay et al. (17)and Liewald et al. (5) have highlighted that VB is incapable of identifying mucosal abnormalities such as erythema, hemorrhage, and friability. This is due to the intrinsic limitation of VB, which relies on density-based rendering and cannot capture subtle surface changes. As such, while VB may be valuable for structural assessment, it lacks the capability for mucosal evaluation and tissue sampling.

Another strength of VB, emphasized in our study and supported by literature, is its ability to detect extrinsic airway compression. In our study, VB identified 15 cases of external compression, compared to only 2 detected by FOB. This advantage arises from VB's ability to incorporate multiplanar reformatted (MPR) images, enabling detailed assessment of surrounding structures. In one of our cases, VB identified airway narrowing caused by calcified lymphadenopathy that was indistinguishable via FOB. Similar findings have been reported in lymphoma and chronic inflammation cases by Fleiter et al. (16), where VB provided a clearer understanding of compression-related changes.

Our ROC curve analysis further validated the high diagnostic performance of VB, with an area under the curve (AUC) of 0.93. This supports the reliability of VB in distinguishing pathological from normal airway segments. Previous studies by Vining and Summeret al. (18,12) and subsequent trials have also demonstrated similar ROC performance of VB in airway lesion evaluation.

Despite its advantages, VB has several limitations. As demonstrated in our study and others (19,20), it cannot provide histological diagnosis, evaluate mucosal color or texture, or assess dynamic airway conditions such as tracheobronchomalacia. Furthermore, VB’s accuracy decreases for lesions smaller than 5 mm. This was evident in our study where two small endoluminal lesions were missed, possibly due to their sub-5 mm size, a finding echoed by Summers et al. (12), who noted VB sensitivity significantly improves with lesions >5 mm.Our study supports the growing body of evidence that MDCT-based virtual bronchoscopy is a highly valuable, non-invasive modality for airway assessment. While it cannot replace FOB—particularly for mucosal evaluation and biopsy—it offers significant advantages in terms of patient comfort, visualization beyond stenoses, and structural assessment. VB serves as a powerful complementary tool to FOB and may be especially useful in pre-procedural planning and in patients for whom bronchoscopy is contraindicated

This study demonstrated that multi-detector computed tomography (MDCT) virtual bronchoscopy (VB) is a highly effective, non-invasive imaging modality for the evaluation of tracheobronchial lesions. VB showed excellent sensitivity (95.7%) and high overall diagnostic accuracy (92.0%) when compared with the reference standard, fiberoptic bronchoscopy (FOB). It was particularly superior in visualizing airway segments distal to high-grade stenoses and in detecting extraluminal compressions, offering valuable anatomical information that FOB could not always provide.

However, VB was limited in detecting subtle mucosal abnormalities and small endoluminal lesions, which were better visualized by FOB. Moreover, the inability of VB to perform biopsies or evaluate mucosal color and texture remains a critical limitation.

Given its strengths and limitations, VB should not be viewed as a replacement for FOB but rather as a complementary diagnostic tool. When used in conjunction with FOB, VB can enhance diagnostic confidence, facilitate procedural planning, and improve patient safety—particularly in cases where FOB is contraindicated or incomplete.a

1. Pereira W Jr, Kovnat DM, Snider GL. A prospective cooperative study of complications following bronchoscopy. Chest. 1978;73(6):813–6. doi:10.1378/chest.73.6.813
2. Dialani V, Ernst A, Sun M, et al. MDCT detection of airway stent complications: Comparison with bronchoscopy. Am J Roentgenol. 2008;191(5):1576–80. doi:10.2214/AJR.07.4031
3. Heyer CM, Nuesslein TG, Jung D, et al. Tracheobronchial anomalies and stenoses: detection with low-dose multidetector CT with virtual tracheobronchoscopy—comparison with flexible tracheobronchoscopy. Radiology. 2007;242(2):542–9. doi:10.1148/radiol.2422051962
4. Hoppe H, Walder B, Sonnenschein M, et al. Multidetector CT virtual bronchoscopy to grade tracheobronchial stenosis. AJR Am J Roentgenol. 2002;178(5):1195–200. doi:10.2214/ajr.178.5.1781195
5. Liewald F, Lang G, Fleiter T, et al. Comparison of virtual and fiberoptic bronchoscopy. Thorac Cardiovasc Surg. 1998;46(6):361–4. doi:10.1055/s-2007-1010284
6. Burke AJ, Vining DJ, McGuirt WF, et al. Evaluation of airway obstruction using virtual endoscopy. Laryngoscope. 2000;110(1):23–9. doi:10.1097/00005537-200001000-00006
7. Haponik EF, Aquino SL, Vining DJ. Virtual bronchoscopy. Clin Chest Med. 1999;20(1):201–17. doi:10.1016/S0272-5231(05)70041-4
8. McAdams HP, Goodman PC, Kussin P. Virtual bronchoscopy for directing transbronchial needle aspiration of hilar and mediastinal lymph nodes: a pilot study. AJR Am J Roentgenol. 1998;170(5):1361–4. doi:10.2214/ajr.170.5.9574604
9. Summers RM. Navigational aids for real-time virtual bronchoscopy. AJR Am J Roentgenol. 1997;168(5):1165–70. doi:10.2214/ajr.168.5.9129415
10. Ferretti G. Virtual endoscopy: which indications? Rev Mal Respir. 1999;3:59–60.
11. Bauer TL, Steiner KV. Virtual bronchoscopy: clinical applications and limitations. Surg Oncol Clin N Am. 2007;16(2):323–36. doi:10.1016/j.soc.2007.01.001
12. Summers RM, Shaw DJ, Shelhamer JH. CT virtual bronchoscopy of simulated endobronchial lesions: effect of scanning, reconstruction, and display settings and potential pitfalls. AJR Am J Roentgenol. 1998;170(4):947–50. doi:10.2214/ajr.170.4.9530044
13. Amorico MG, Drago A, Vetruccio E, et al. Tracheobronchial stenosis: role of virtual endoscopy in diagnosis and follow-up after therapy. Radiol Med. 2006;111(7):1064–77. doi:10.1007/s11547-006-0072-7
14. Ferretti GR, Kocier M, Calaque O, et al. Follow-up after stent insertion in the tracheobronchial tree: role of helical computed tomography in comparison with fiberoptic bronchoscopy. Eur Radiol. 2003;13(5):1172–8. doi:10.1007/s00330-002-1691-6
15. Hafez SA, Helmy SA, Mourad ST, Morsi TS, Abou zeid NA. Virtual and fiber-optic bronchoscopy in patients with indication for tracheobronchia evaluation.
16. Fleiter, E. M. Merkle, A. J. Aschoff, G. Lang, M. Stein, J. Gorich, F. Liewald, N. Rilinger, R. Sokiranski. Comparison of Real-Time Virtual and Fibreoptic Bronchoscopy in Patients with Bronchial Carcinoma: Opportunities and Limitations. American Journal of Roentgenology. 1997;169:1591-1595
17. Beker Acay, S. Sarinc-Ulasli, E. Ünlü, E. Kaçar, E. Gunay, N. okur, C. Ozdemir, A. Yucel; Afyonkarahisar/ TR Can virtual bronchoscopy be a complementary method for fibreoptic bronchoscopy?
18. Vining DJ, Liu K, Choplin RH, Haponik EF. Virtual bronchoscopy. Relationships of virtual reality endobronchial simulations to actual bronchoscopic findings. Chest. 1996;109:549–53. doi: 10.1378/chest.109.2.549.
19. Heyer CM, Nuesslein TG, Jung D, Peters SA, Lemburg SP, Rieger CH, et al. Tracheobronchial anomalies and stenoses: detection with low-dose multidetector CT with virtual tracheobronchoscopy--comparison with flexible tracheobronchoscopy. Radiology. 2007;242:542–9. doi: 10.1148/radiol.2422060153. [DOI] [PubMed] [Google Scholar]
20. .Finkelstein SE, Schrump DS, Nguyen DM, Hewitt SM, Kunst TF, Summers RM. Comparative evaluation of super high-resolution CT scan and virtual bronchoscopy for the detection of tracheobronchial malignancies. Chest. 2003;124:1834–40. doi: 10.1378/chest.124.5.1834.