HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Figures Only Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Onodera, Y. Articles by Miyasaka, K. Search for Related Content PubMed PubMed Citation Articles by Onodera, Y. Articles by Miyasaka, K. Social Bookmarking                      What's this?

Enhanced Virtual Bronchoscopy Using the Pulmonary Artery: Improvement in Route Mapping for Ultraselective Transbronchial Lung Biopsy

¹ Department of Radiology, Hokkaido University School of Medicine, North 15 West 7, Kita-Ku, Sapporo 060-8638, Japan.
² First Department of Medicine, Hokkaido University School of Medicine, Sapporo 060-8638, Japan.

Received September 25, 2003; accepted after revision March 31, 2004.

 
Address correspondence to Y. Onodera (yono{at}radi.med.hokudai.ac.jp).

Abstract

Top Abstract Introduction Materials and Methods Results Discussion References

 
OBJECTIVE. We evaluated a new simulation method for ultraselective transbronchial lung biopsy using the pulmonary artery.

MATERIALS AND METHODS. A new method for enhanced virtual bronchoscopy using the pulmonary artery was developed for ultraselective transbronchial lung biopsy. In a volunteer study of healthy adults, three radiologists with different levels of experience independently reconstructed conventional virtual bronchoscopy and enhanced virtual bronchoscopy using the pulmonary artery until reaching the farthest point of the bronchus and pulmonary artery. The bronchovascular branch order and the minimum luminal diameter (e.g., for bronchus and artery) for reconstruction were compared. In a clinical study, virtual bronchoscopy and enhanced virtual bronchoscopy using the pulmonary artery were compared with regard to accessibility to target lesions in 40 patients with small pulmonary nodules or ground-glass opacities. A comparison between the simulated bronchial route reconstructions and actual bronchoscopic routes on biopsy was made to determine the efficacy of each reconstruction method.

RESULTS. In the volunteer study, quality of enhanced virtual bronchoscopy using the pulmonary artery was not significantly affected by the experience levels of the radiologists. In the clinical study, bronchial reconstruction was successful in guiding to a bronchoscopic tumor in 35 (87.5%) of 40 cases. The maximum bronchial order on reconstruction was the sixth for the virtual bronchoscopy group and the eighth for the group with enhanced virtual bronchoscopy using the pulmonary artery (p < 0.001, Wilcoxon's signed rank test). The bronchial route reconstructed on enhanced virtual bronchoscopy using the pulmonary artery agreed with the actual biopsy routes in 30 cases (85.7%), but those reconstructed on virtual bronchoscopy alone agreed in only eight cases (22.9%) (p < 0.001, chi-square test).

CONCLUSION. Enhanced virtual bronchoscopy using the pulmonary artery is feasible and helpful for ultraselective transbronchial lung biopsy of small nodules in the lung.

Introduction

Top Abstract Introduction Materials and Methods Results Discussion References

 
Recent advances in MDCT have resulted in improved quality of 3D images. Virtual endoscopy is a fly-through technique in a 3D object, which is usually constructed using the surface-rendering method with the region-growing method [1] or the volume-rendering method [2, 3]. Virtual endoscopic object reconstruction by auto segmentation has become possible with the improvements in workstations. In abdominal radiology, virtual endoscopy has proven effective in the detection of small polyps and malignant tumors [3]. In thoracic radiology, virtual endoscopy has been used for evaluating the bronchial tree [1–21]. In previous studies, the role of virtual bronchoscopy has been limited to the evaluation of proximal airway diseases [1, 2, 4–9, 12–21]. Few reports have examined the use of virtual bronchoscopy in the peripheral airway system, although the potential has been recognized [4]. Indeed, one study suggested the usefulness of virtual bronchoscopy simulation for selective transbronchial lung biopsy [22]. However, the efficacy of virtual bronchoscopy simulation in lung biopsy has remained uncertain for small peripheral lesions. The spatial resolution of virtual bronchoscopy is not sufficient to allow construction of a route map for narrow bronchial branches [10, 11].

The pulmonary artery is an important structure in the lung because it forms a unit, the bronchovascular bundle, with the bronchus. In the periphery of the lung, a bronchial lumen cannot be observed on thin-section CT, but the pulmonary artery is visible. The pulmonary artery and the bronchus in the bronchovascular bundle are close to each other, so the pulmonary artery is used for understanding bronchial anatomy [23]. Enhanced virtual bronchoscopy using the pulmonary artery could be useful to guide biopsy routes to tumors, particularly when bronchial lumina are not visible on CT. To our knowledge, this use of virtual endoscopy has not been reported in a clinical setting.

In this study, we examined the efficacy of enhanced virtual bronchoscopy using the pulmonary artery for the biopsy of small lung tumors in the periphery of the lung.

Materials and Methods

Top Abstract Introduction Materials and Methods Results Discussion References

 
All CT scans were obtained using a 4-MDCT scanner (Aquilion Multi, Toshiba). Scanning conditions were as follows: slice collimation, 0.5 mm; helical pitch, 2.5 and 6; 135 kVp with 250 mA; and 0.5 sec per rotation for the volunteer study. A helical pitch of 2.5 is the minimum speed of table transformation, and a helical pitch of 6 is the maximum speed of table transformation. The following equation was used for reconstruction parameters:

where FC and RASP are the original marks used by the Toshiba scanners. All data sets acquired using helical scanning were reconstructed to isotropic voxel data sets.

Volunteer Study
Three radiologists independently constructed virtual endoscopic images of a healthy volunteer to determine whether a radiologist's experience has an effect on 3D reconstruction. One of these radiologists (A) is particularly skillful in virtual endoscopic reconstruction because this person invented the technique and has worked with more than 100 3D objects. The other two radiologists (B and C) are board-certified and have ample experience in chest radiology, each having worked on more than 50 3D reconstructions. Contrast material was not used. All lung CT data were obtained in one breath-hold. Isotropic reconstruction was performed for raw data sets, and the reconstructed data were transferred to a 3D workstation (Virtual Place, Medical Imaging Laboratory). The volume-rendering method was used for the virtual endoscopy algorithm. Three-dimensional objects were automatically reconstructed in 30 sec. For viewing the inner side of the 3D lumina, a fly-through technique was used. Virtual endoscopic thresholds used were –600 and –900 H (virtual bronchoscopy: –800 to –900 H; enhanced virtual bronchoscopy using the pulmonary artery: –600 to –800 H). Each radiologist counted branch orders and measured intraluminal diameters at the farthest point of the bronchus and pulmonary artery on virtual endoscopy. Enhanced virtual bronchoscopy using the pulmonary artery has high image quality for the pulmonary artery in the periphery of the lung. The image quality was similar to that for the central airway on virtual bronchoscopy (Figs. 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 2A, 2B, 2C, 2D, and 2E). The inner opacity of the pulmonary artery is homogeneous in the peripheral lung. The opacity difference between the pulmonary artery and air was sufficient to reconstruct the 3D pulmonary artery. Enhanced virtual bronchoscopy using the pulmonary artery is simple and noninvasive, and no contrast material is required. To our knowledge, no previous reports have been published on using structures other than those in the lung to reach tumors in the periphery of the lung.

View larger version (94K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1A. —Images in 37-year-old healthy male volunteer show definition of enhanced virtual bronchoscopy using pulmonary artery. At farthest point on virtual bronchoscopy (A), next branch was unclear at any threshold, but peripheral bronchus was open and clear on CT scans (B and C).

View larger version (141K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1B. —Images in 37-year-old healthy male volunteer show definition of enhanced virtual bronchoscopy using pulmonary artery. At farthest point on virtual bronchoscopy (A), next branch was unclear at any threshold, but peripheral bronchus was open and clear on CT scans (B and C).

View larger version (166K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1C. —Images in 37-year-old healthy male volunteer show definition of enhanced virtual bronchoscopy using pulmonary artery. At farthest point on virtual bronchoscopy (A), next branch was unclear at any threshold, but peripheral bronchus was open and clear on CT scans (B and C).

View larger version (103K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1D. —Images in 37-year-old healthy male volunteer show definition of enhanced virtual bronchoscopy using pulmonary artery. At beginning of enhanced virtual bronchoscopy (D) of pulmonary artery reconstruction for peripheral branch, virtual endoscopic lumen is still clear. Tip of virtual endoscope was moved from bronchus to pulmonary artery on same bronchovascular bundle (E and F).

View larger version (145K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1E. —Images in 37-year-old healthy male volunteer show definition of enhanced virtual bronchoscopy using pulmonary artery. At beginning of enhanced virtual bronchoscopy (D) of pulmonary artery reconstruction for peripheral branch, virtual endoscopic lumen is still clear. Tip of virtual endoscope was moved from bronchus to pulmonary artery on same bronchovascular bundle (E and F).

View larger version (165K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1F. —Images in 37-year-old healthy male volunteer show definition of enhanced virtual bronchoscopy using pulmonary artery. At beginning of enhanced virtual bronchoscopy (D) of pulmonary artery reconstruction for peripheral branch, virtual endoscopic lumen is still clear. Tip of virtual endoscope was moved from bronchus to pulmonary artery on same bronchovascular bundle (E and F).

View larger version (124K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1G. —Images in 37-year-old healthy male volunteer show definition of enhanced virtual bronchoscopy using pulmonary artery. At end of enhanced virtual bronchoscopy (G), enhanced virtual bronchoscopy using pulmonary artery reached target at subpleural region. H is axial CT magnified image focused on periphery. Blue track in B, E, and H indicates road map.

View larger version (123K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 1H. —Images in 37-year-old healthy male volunteer show definition of enhanced virtual bronchoscopy using pulmonary artery. At end of enhanced virtual bronchoscopy (G), enhanced virtual bronchoscopy using pulmonary artery reached target at subpleural region. H is axial CT magnified image focused on periphery. Blue track in B, E, and H indicates road map.

View larger version (41K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 2A. —45-year-old man with primary lung adenocarcinoma in left lower lobe. Virtual bronchoscopy images (beginning at A and ending at C [but excluding B]) failed at fourth bronchial order. Images from enhanced virtual bronchoscopy using pulmonary artery (D) were successful in route mapping to tumor (seventh bronchial order). Images from actual bronchoscopy (beginning at B and ending at E [but excluding C and D]) show correlation with virtual bronchoscopy and enhanced virtual bronchoscopy. All arrows show next routes where virtual bronchoscopy or actual bronchoscopy is inserted.

View larger version (29K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 2B. —45-year-old man with primary lung adenocarcinoma in left lower lobe. Virtual bronchoscopy images (beginning at A and ending at C [but excluding B]) failed at fourth bronchial order. Images from enhanced virtual bronchoscopy using pulmonary artery (D) were successful in route mapping to tumor (seventh bronchial order). Images from actual bronchoscopy (beginning at B and ending at E [but excluding C and D]) show correlation with virtual bronchoscopy and enhanced virtual bronchoscopy. All arrows show next routes where virtual bronchoscopy or actual bronchoscopy is inserted.

View larger version (45K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 2C. —45-year-old man with primary lung adenocarcinoma in left lower lobe. Virtual bronchoscopy images (beginning at A and ending at C [but excluding B]) failed at fourth bronchial order. Images from enhanced virtual bronchoscopy using pulmonary artery (D) were successful in route mapping to tumor (seventh bronchial order). Images from actual bronchoscopy (beginning at B and ending at E [but excluding C and D]) show correlation with virtual bronchoscopy and enhanced virtual bronchoscopy. All arrows show next routes where virtual bronchoscopy or actual bronchoscopy is inserted.

View larger version (31K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 2D. —45-year-old man with primary lung adenocarcinoma in left lower lobe. Virtual bronchoscopy images (beginning at A and ending at C [but excluding B]) failed at fourth bronchial order. Images from enhanced virtual bronchoscopy using pulmonary artery (D) were successful in route mapping to tumor (seventh bronchial order). Images from actual bronchoscopy (beginning at B and ending at E [but excluding C and D]) show correlation with virtual bronchoscopy and enhanced virtual bronchoscopy. All arrows show next routes where virtual bronchoscopy or actual bronchoscopy is inserted.

View larger version (23K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 2E. —45-year-old man with primary lung adenocarcinoma in left lower lobe. Virtual bronchoscopy images (beginning at A and ending at C [but excluding B]) failed at fourth bronchial order. Images from enhanced virtual bronchoscopy using pulmonary artery (D) were successful in route mapping to tumor (seventh bronchial order). Images from actual bronchoscopy (beginning at B and ending at E [but excluding C and D]) show correlation with virtual bronchoscopy and enhanced virtual bronchoscopy. All arrows show next routes where virtual bronchoscopy or actual bronchoscopy is inserted.

Statistical analysis was performed using two-factor factorial analysis of variance. A multiple comparison test (the Scheffé F test) was added if an interaction was found in a result of the two-factor factorial analysis of variance. Statistical significance was set at the 5% level.

Clinical Study
The CT scanning conditions for virtual endoscopy were the same as in the volunteer study. Contrast material was not used. Scanning was performed during one breath-hold. All relevant branches of the bronchus and pulmonary arteries were scanned. CT fluoroscopy was also used to assist the biopsy procedure in this study. The parameters were as follows: 5-mm collimation, 135 kVp with 10 mA, and 0.5 sec per rotation. Scanning with CT fluoroscopy was performed in 30 sec.

Thirty-nine patients with 40 lesions were enrolled in this study (16 men, 24 women; age range, 49–80 years). The diameters of the lesions were 2 cm or less in all patients (32 nodules, five ground-glass opacities, and two nodules with ground-glass opacities). All lesions were located in the periphery of the lung.

Virtual endoscopy was performed within 2 weeks before transbronchial lung biopsy. Virtual endoscopic images were constructed in the same way as described for the volunteer study. Figures 1A, 1B, 1C, 1D, 1E, 1F, 1G, and 1H shows a typical process for enhanced virtual bronchoscopy using the pulmonary artery. First, the bronchus was reconstructed as peripherally as possible (i.e., until the bronchial lumen was invisible). Second, the pulmonary artery was reconstructed to track the bronchovascular bundle. In all cases, a radiologist made fly-through movies from virtual endoscopic images in 30 min.

Two pulmonologists simulated the bronchoscopic procedure using the virtual endoscopy fly-through movie. This simulation was repeated until they were confident of the anatomy of the biopsy. For all patients, 15 mg of pentazocine hydrochloride and 0.5 mg of atropine sulfate were used as premedication, and 4% lidocaine was used for local anesthesia. In this study, an ultrathin bronchoscope BF-type XP-40 (Olympus) was used. The external diameter was 2.8 mm, and the inner diameter (i.e., the biopsy channel) was 1.2 mm. This bronchoscope can be inserted selectively into peripheral bronchial branches farther than the fifth order [22]. The process of a lung biopsy is shown in Figures 3A, 3B, 3C, and 3D. The bronchoscope was inserted into the bronchial branches under virtual endoscopic guidance (Figs. 3A and 3B). The position of the bronchoscope tip was adjusted using CT fluoroscopy. After adjusting the position of the bronchoscope, we performed the biopsy (Fig. 3C). To avoid unnecessary X-ray exposure, we limited the time of CT fluoroscopy to 5 min.

View larger version (67K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3A. —Agreement of route map with biopsy path is shown in images from 65-year-old woman with lung cancer in right lower lobe. Image from virtual bronchoscopy shows most distal point reached.

View larger version (133K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3B. —Agreement of route map with biopsy path is shown in images from 65-year-old woman with lung cancer in right lower lobe. CT image with road map (blue) shows route of virtual bronchoscopy.

View larger version (148K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3C. —Agreement of route map with biopsy path is shown in images from 65-year-old woman with lung cancer in right lower lobe. Flouroscopic CT images show tips of ultrathin bronchoscope and bioptome reaching target lesion, which coincided with road map image.

View larger version (145K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3D. —Agreement of route map with biopsy path is shown in images from 65-year-old woman with lung cancer in right lower lobe. Flouroscopic CT images show tips of ultrathin bronchoscope and bioptome reaching target lesion, which coincided with road map image.

The efficacy of enhanced virtual bronchoscopy using the pulmonary artery was evaluated using the success criteria described for the volunteer study. The success of virtual endoscopic reconstruction was defined as 3D anatomy on virtual endoscopy (i.e., bronchial bifurcation, trifurcation, and branching angle) accurately agreeing with that encountered during actual bronchoscopy. Biopsy success was defined as obtaining biopsy specimens.

The chi-square test was used to measure biopsy success between virtual bronchoscopy and enhanced virtual bronchoscopy using the pulmonary artery, and Fisher's exact test was used to examine the relationship between the success of lung biopsy and the success of the bronchial route mapping by each method. The Mantel-Haenszel test was used to evaluate improvement for biopsy and route-mapping success between the two methods. Wilcoxon's signed rank test was performed for the branch order at the farthest point reached. Statistical significance was set at 5%.

Results

Top Abstract Introduction Materials and Methods Results Discussion References

 
Volunteer Study
The smallest average bronchial diameter reconstructed by the three radiologists was 1.5 mm. No significant difference in bronchial diameter was observed among the three radiologists (Fig. 4A). The smallest average pulmonary artery diameter reconstructed by the three radiologists was 0.8 mm. The mean value of the maximum branch order differed significantly between the bronchus and the pulmonary artery among the radiologists (p < 0.001, two-factor factorial analysis of variance) (Fig. 4B). The farthest average bronchovascular branch order reached was 7.5 for virtual bronchoscopy and 10 for enhanced virtual bronchoscopy using the pulmonary artery.

View larger version (18K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 4A. —Results of statistical analysis of three radiologists shown as mean (•) ± 2 SD (whiskers). A, B, and C are qualified radiologists. Radiologist A is highly experienced in 3D building, B and C are not. Br = conventional virtual bronchoscopy, PA = enhanced virtual bronchoscopy using pulmonary artery. Graph shows no significant difference in luminal diameters among three radiologists regarding limit of bronchus diameter, which was 1.5 mm. Significant difference was found in reconstructed diameter among radiologist A (0.75 mm), radiologist B (1.1 mm), and radiologist C (0.9 mm). Significant differences were found in luminal diameters between bronchus and pulmonary artery among radiologists.

View larger version (18K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 4B. —Results of statistical analysis of three radiologists shown as mean (•) ± 2 SD (whiskers). A, B, and C are qualified radiologists. Radiologist A is highly experienced in 3D building, B and C are not. Br = conventional virtual bronchoscopy, PA = enhanced virtual bronchoscopy using pulmonary artery. Graph shows no significant difference among three radiologists regarding limit of bronchial order, average of which was 7.5. Significant difference was found between radiologist A and other two radiologists regarding limit of pulmonary arterial order: 11.8 order, radiologist A; 9.8 order, radiologist B; and 9.2 order, radiologist C.

Clinical Study
A significant difference in the most peripheral branch order for luminal reconstruction was observed between virtual bronchoscopy and enhanced virtual bronchoscopy using the pulmonary artery (p < 0.001): sixth branch order for virtual bronchoscopy, eighth branch order for enhanced virtual bronchoscopy using the pulmonary artery (Fig. 5).

View larger version (12K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 5. —Graph shows maximum bronchial order in clinical cases. For virtual bronchoscopy, maximum was sixth branch. For enhanced virtual bronchoscopy enhanced using pulmonary artery, maximum was eighth branch. Results are shown by median (•) and 25th and 75th percentile values (whiskers). Significant difference was found between virtual bronchoscopy and enhanced virtual bronchoscopy using pulmonary artery for median limit of branch order.

Bronchial route mapping was successful in 35 of the 40 cases. Virtual bronchoscopy reached the target in only eight of these 35 cases. For the remaining 27 cases, enhanced virtual bronchoscopy using the pulmonary artery was successful in reaching the target. Enhanced virtual bronchoscopy using the pulmonary artery failed to reconstruct correct biopsy routes, and biopsies were unsuccessful in four cases. The failures were caused by peripheral branches that were too small for virtual endoscopic reconstruction and by artifacts on virtual endoscopy that were mistaken for bronchi. Virtual endoscopic reconstruction was successful but biopsy failed in five cases. The failures were caused by too steep a branching angle for the bronchoscope to be inserted into the next branch or by an unexpectedly long route (i.e., the bronchoscope could not reach the target). In one case, virtual endoscopic reconstruction was not correct but the biopsy was successful. In that instance, multiple routes to the target were found. The bioptome passed along an unplanned route and reached the target.

A significant difference in biopsy success was observed between the two methods (p < 0.01, chi-square test) (Table 1). Conventional virtual bronchoscopy was successful in 17 of 40 patients and enhanced virtual bronchoscopy was successful in 30 of 39. In conventional virtual bronchoscopy, no significant relationship was seen between biopsy success and route mapping success using Fisher's exact test (p = 0.2823) (Table 2). When route mapping was successful, the biopsy was successful in eight of nine patients. When route mapping failed, biopsy failed in 22 of 31 patients. In enhanced virtual bronchoscopy using the pulmonary artery, when the route mapping was successful, the biopsy was successful in 30 of 35 patients; when the route planning failed, the biopsy failed in four of five patients. The difference was significant. A statistically significant difference in biopsy success rates was observed between the virtual bronchoscopy group and enhanced virtual bronchoscopy using the pulmonary artery group when measured using the Mantel-Haenszel test (p < 0.001) (Tables 2 and 3).

Discussion

Top Abstract Introduction Materials and Methods Results Discussion References

 
Advantages of Enhanced Virtual Bronchoscopy Using the Pulmonary Artery
When we began this study, enhanced virtual bronchoscopy using the pulmonary artery was a new virtual endoscopic technique, and its limitations with regard to spatial resolution were unknown. Furthermore, whether a radiologist's experience affected virtual endoscopy quality was unclear. Before this clinical study, we clarified these issues using a volunteer study. In the volunteer study, order and inner diameter of the bronchus reconstructed were not affected by the radiologist's experience. The most distal order of the bronchus was 7.5 using conventional virtual bronchoscopy. These results were consistent with other reports [10, 11]. Enhanced virtual bronchoscopy using the pulmonary artery reached the 10th bronchial order on average, with a minimum average diameter of 0.8 mm.

When we used enhanced virtual bronchoscopy using the pulmonary artery, we saw significant improvement in maximum bronchial order reconstructed (10th on average) among radiologists A, B, and C. Although a difference in maximum bronchial order was seen between radiologist A and radiologists B and C, the order was always higher for enhanced virtual bronchoscopy using the pulmonary artery for each individual radiologist. We found a difference in diameter between the bronchi and pulmonary artery in the periphery on reconstruction. Although such a comparison has no clinical relevance (a comparison between different anatomic structures is not informative), the fact that the difference was seen in almost the same manner among the three radiologists for healthy bronchovascular bundles supports the notion that enhanced virtual bronchoscopy using the pulmonary artery is a stable 3D reconstruction method that can be applied to clinical patients. With a little more experience, board-certified radiologists will probably reach the level of technical expertise of radiologist A.

One way of achieving reviewer agreement may be to optimize the conditions for enhanced virtual bronchoscopy using the pulmonary artery. We used Hounsfield unit values from –600 to –800 H for visualization of the inner lumen of the pulmonary artery. These conditions allowed visualization of small branches even when the diameter was 1 mm. Thus, enhanced virtual bronchoscopy using the pulmonary artery under these conditions had adequate spatial resolution to detect narrow branches in clinical use. Although each radiologist using 3D technology may develop his or her own threshold preferences, we can define a narrow range of conditions for optimization of enhanced virtual bronchoscopy using the pulmonary artery for each patient. Notably, enhanced virtual bronchoscopy using the pulmonary artery produced high image quality without the need for contrast material (Figs. 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 2A, 2B, 2C, 2D, and 2E).

Route Mapping with Virtual Endoscopy for Transbronchial Lung Biopsy
In the clinical study, the maximum distal region was the sixth order for virtual bronchoscopy and the eighth order for enhanced virtual bronchoscopy using the pulmonary artery. As in the volunteer study, enhanced virtual bronchoscopy using the pulmonary artery allowed reconstruction of higher distal branch orders than virtual bronchoscopy alone. The success of bronchial route mapping led to successful biopsy. Our results clearly show that reconstructing most peripheral bronchial branches is necessary for biopsy success.

In all clinical cases, the diameters of the lesions were 2 cm or less, and the lesions were invisible on conventional radiographic fluoroscopy. The success rate of lung biopsy for small lesions is limited [24–28]. Transbronchial lung biopsy with CT fluoroscopy is useful [29, 30] but is not sufficient for tumors located in the periphery of the lung [24]. We achieved a biopsy success of 77.5% for tumors smaller than 2 cm or those having ground-grass opacity. In previous reports, the success rates for such tumors have been between 5% and 54% [24–28]. Our ultraselective biopsy procedure with enhanced virtual bronchoscopy using the pulmonary artery improved the success rate of lung biopsy.

Simulation is important in transbronchial biopsy for tumors in anatomically complicated sites. Good simulation is effective in reducing the effects of differences in experience among pulmonologists [31–33]. High-resolution CT can help in selection of bronchi leading to lesions [18]. On axial images, 3D understanding of complicated bronchial bifurcation is difficult [18]. Even with multiplanar reconstruction, difficulties remain in evaluating the morphology of narrow airways [16–20]. Asano et al. [22] reported that virtual bronchoscopy was useful for diagnosis or simulation of transbronchial lung biopsy. As shown in Figures 2A, 2B, 2C, 2D, and 2E, conventional virtual bronchoscopy had limitations in reconstruction and was insufficient for lung biopsy. Enhanced virtual bronchoscopy using the pulmonary artery visualized narrower bronchial branches better than virtual bronchoscopy did, even when those branches were invisible on CT. Ultrathin bronchoscopes are now commercially available, and expectations of their ability are high because of their flexibility, thinness, and long length [3]. These bronchoscopes will probably be more frequently used for biopsy of small tumors in the periphery of the lung [3]. Our results suggest that enhanced virtual bronchoscopy using the pulmonary artery will be helpful in ultrathin bronchoscopic biopsy.

In conclusion, enhanced virtual bronchoscopy using the pulmonary artery is feasible and clinically useful for planning ultraselective transbronchial lung biopsy because enhanced virtual bronchoscopy using the pulmonary artery provides more detailed bronchial information than conventional virtual bronchoscopy does.

References

Top Abstract Introduction Materials and Methods Results Discussion References

 

1. Mori K, Deguchi D, Sugiyama J, et al. Tracking of a bronchoscope using epipolar geometry analysis and intensity-based image registration of real and virtual endoscopic images. Med Image Anal2002; 6:321 -336[Medline]
2. Klaus N, Jan W, Martin K, et al. Real-time interactive virtual endoscopy of the tracheo-bronchial system: influence of CT imaging protocols and observer ability. Eur J Radiol1999; 30:50 -54
3. Ferretti GR, Vining DJ, Knoplioch J, et al. Transbronchial tree: three-dimensional spiral CT with bronchoscopic perspective. J Comput Assist Tomogr 1996;20:777 -781[Medline]
4. Naidich DP, Gruden JF, McGuinness G, McCauley DI, Bhalla M. Volumetric (helical/spiral) CT (VCT) of the airways. J Thorac Imaging 1997;12:11 -28[Medline]
5. Seemann MD, Claussen CD. Hybrid 3D visualization of the chest and virtual endoscopy of the tracheobronchial system: possibilities and limitations of clinical application. Lung Cancer2001; 32:237 -246[Medline]
6. Ferretti GR, Knoplioch J, Bricault I, et al. Central airway stenoses: preliminary results of spinal-CT-generated virtual bronchoscopy simulation in 29 patients. Eur Radiol1997; 7:854 -859[Medline]
7. Hoppe H, Waler B, Sonnenschein M, Vock P, Dinkel HP. Multidetector CT virtual bronchoscopy to grade transbronchial stenosis. AJR 2002;178:1195 -1200[Abstract/Free Full Text]
8. McAdams HP, Palmer SM, Erasmus JJ, et al. Bronchial anastomotic complications in lung transplant recipients: virtual bronchoscopy for noninvasive assessment. Radiology1998; 209:689 -695[Abstract/Free Full Text]
9. Summers RM, Selbie WS, Malley JD, et al. Polypoid lesions of airways: early experience with computer-assisted detection by using virtual bronchoscopy and surface curvature. Radiology1998; 208:331 -337[Abstract/Free Full Text]
10. Ferretti GR, Vining DJ, Knoplioch J, et al. Transbronchial tree: three-dimensional spiral CT with bronchoscopic perspective. J Comput Assist Tomogr 1996;20:777 -781
11. Rubin GD, Beaulieu CF, Argiro V, et al. Perspective volume rendering of CT and MR images: applications for endoscopic imaging. Radiology1996; 199:321 -330[Abstract/Free Full Text]
12. Hopper KD, Iyriboz TA, Maharaj RPM, et al. CT bronchoscopy: optimization of imaging parameters. Radiology1998; 209:872 -877[Abstract/Free Full Text]
13. Power NP, Pryor MD, Martin A, et al. Optimization of scanning parameters for CT colonography. Br J Radiol2002; 75:401 -408[Abstract/Free Full Text]
14. Laroche C, Fairbairn I, Moss H, et al. Role of computed tomographic scanning of the thorax prior to bronchoscopy in the investigation of suspected lung cancer. Thorax2000; 55:359 -363[Abstract/Free Full Text]
15. Hopper KD, Iyriboz AT, Wise SW, et al. Mucosal detail at CT virtual reality: surface versus volume rendering. Radiology2000; 214:517 -522[Abstract/Free Full Text]
16. Konen E, Katz M, Rozenman J, Ben-Shlush A, Itzchak Y, Szeinberg A. Virtual bronchoscopy in children: early clinical experience. AJR 1998; 171:1699 -1702[Abstract/Free Full Text]
17. Remy J, Remy-Jardin M, Artaud D, Fribourg M. Multiplanar and three-dimensional reconstruction techniques in CT: impact on chest diseases. Eur Radiol 1998;8:335 -351[Medline]
18. Boiselle PM, Reynolds KF, Ernst A. Multiplanar and three-dimensional imaging of the central airways with multidetector CT. AJR 2002;179:301 -308[Free Full Text]
19. Rapp-Bernhardt UR, Welte T, Doehring W, Kropf S, Bernhardt TM. Diagnostic potential of virtual bronchoscopy: advantages in comparison with axial CT slices, MPR and mIP? Eur Radiol2000; 10:981 -988[Medline]
20. Orantin E, Geiger B, Lindbichler F, et al. CT-based virtual tracheobronchoscopy in children: comparison with axial CT and multiplanar reconstruction—preliminary results. Pediatr Radiol 2002;32:8 -15[Medline]
21. Hopper KD, Lucas TA, Glesson K, et al. Transbronchial biopsy with virtual CT bronchoscopy and nodal highlighting. Radiology2001; 221:531 -536[Abstract/Free Full Text]
22. Asano F, Matsuno Y, Komaki C, et al. CT-guided transbronchial diagnosis using ultrathin bronchoscope for small peripheral pulmonary lesions [in Japanese]. Nihon Kokyuki Gakkai Zasshi2002; 40:11 -16[Medline]
23. Webb WR, Muller NL, Naidich DP. High-resolution CT of the lung, 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001: 49-69
24. Baaklini WA, Reinoso MA, Gorin AB, Sharafkaneh A, Manian P. Diagnostic yield of fiberoptic bronchoscopy in evaluating solitary pulmonary nodules. Chest2000; 17:1049 -1054
25. Chechani V. Bronchoscopic diagnosis of solitary pulmonary nodules and lung masses in the absence of endobronchial abnormality. Chest 1996;109:620 -625[Abstract/Free Full Text]
26. Zavala DC. Diagnostic fiberoptic bronchoscopy: techniques and results of biopsy in 600 patients. Chest1975; 68:12 -19[Abstract/Free Full Text]
27. Kvale PA, Frederick LTC, Bode R, Kini S. Diagnostic accuracy in lung cancer. Chest1976; 69:752 -757[Abstract/Free Full Text]
28. Torrington KG, Kern JD. The utility of fiberoptic bronchoscopy in the evaluation of solitary pulmonary nodules. Chest1993; 104:1021 -1024[Abstract/Free Full Text]
29. Kazuhiko K, Ryoichi K, Hirofumi A, et al. Guidance with real-time CT fluoroscopy: early clinical experience. Radiology1996; 200:851 -856[Abstract/Free Full Text]
30. White CS, Weiner EA, Patel P, et al. Transbronchial needle aspiration: guidance with CT fluoroscopy. Chest2000; 118:1630 -1638[Abstract/Free Full Text]
31. Haponik EF, Russel GB, Beamis JF Jr, et al. Bronchoscopy training: current fellows' experiences and some concerns for the future. Chest 2000;118:625 -630[Abstract/Free Full Text]
32. Ost D, DeRosiers A, Britt EJ, Fein AM, Lesser ML, Mehta AC. Assessment of a bronchoscopy simulator. Am J Respir Crit Care Med 2001;164:2248 -2255[Abstract/Free Full Text]
33. Colt HG, Crawford SW, Galbraith O. Virtual reality bronchoscopy simulation: a revolution in procedural training. Chest2001; 120:1333 -1339[Abstract/Free Full Text]

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				M. Nishimura Application of Three-Dimensional Airway Algorithms in a Clinical Study Proceedings of the ATS, December 15, 2008; 5(9): 910 - 914. [Abstract] [Full Text] [PDF]

				N. Shinagawa, K. Yamazaki, Y. Onodera, H. Asahina, E. Kikuchi, F. Asano, K. Miyasaka, and M. Nishimura Factors Related to Diagnostic Sensitivity Using an Ultrathin Bronchoscope Under CT Guidance Chest, February 1, 2007; 131(2): 549 - 553. [Abstract] [Full Text] [PDF]

				T. R. Gildea, P. J. Mazzone, D. Karnak, M. Meziane, and A. C. Mehta Electromagnetic Navigation Diagnostic Bronchoscopy: A Prospective Study Am. J. Respir. Crit. Care Med., November 1, 2006; 174(9): 982 - 989. [Abstract] [Full Text] [PDF]

				M. Hasegawa, Y. Nasuhara, Y. Onodera, H. Makita, K. Nagai, S. Fuke, Y. Ito, T. Betsuyaku, and M. Nishimura Airflow Limitation and Airway Dimensions in Chronic Obstructive Pulmonary Disease Am. J. Respir. Crit. Care Med., June 15, 2006; 173(12): 1309 - 1315. [Abstract] [Full Text] [PDF]

				H. Asahina, K. Yamazaki, Y. Onodera, E. Kikuchi, N. Shinagawa, F. Asano, and M. Nishimura Transbronchial Biopsy Using Endobronchial Ultrasonography With a Guide Sheath and Virtual Bronchoscopic Navigation Chest, September 1, 2005; 128(3): 1761 - 1765. [Abstract] [Full Text] [PDF]

This Article Abstract Figures Only Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Onodera, Y. Articles by Miyasaka, K. Search for Related Content PubMed PubMed Citation Articles by Onodera, Y. Articles by Miyasaka, K. Social Bookmarking                      What's this?