Ultrathin Bronchoscopic Barium Marking With Virtual Bronchoscopic Navigation for Fluoroscopy-Assisted Thoracoscopic Surgery

Intraoperative patient radiation dose from cone-beam computed tomography in thoracic surgery

BACKGROUND

Several methods can be used to intraoperatively identify pulmonary lesion using radiation technology. However, little is known about patient radiation exposure during chest surgery. We aimed to measure patients' radiation exposure from cone-beam computed tomography (CBCT) used in a hybrid operating room.

METHODS

This retrospective study included patients who underwent surgical treatment in a hybrid operating room between April 2019 and December 2023 at the Teikyo University Hospital. All data was obtained prospectively, but the study was approved by the IRB as a retrospective study because of repeated extensions of study period in order to collect more cases. Skin radiation exposure was measured using five wearable dosimeters per patient. The measurements were compared to cumulative Air Kerma. Furthermore, the radiation exposure dose on the surgical side, which cannot be measured, was estimated by computer simulation.

RESULTS

Among 182 patients who underwent surgery in a hybrid operating room, radiation exposure measurements were conducted on 67 patients. The patients' mean age was 60.7 years. The average number of CBCT scans was 2.1 (1-5) and the intraoperative identification rate was 100%, with no marking-related complications. Average patient's skin radiation dose was 3.69 ± 5.48 mGy per dosimeter, and cumulative Air Kerma was 25.4 ± 19.3 mGy. The highest radiation exposure was recorded in the 5th intercostal space whereas the lowest was measured in the supraclavicular or 11th intercostal spaces. Referring to phantom and computer simulation data, the 5th and 8th intercostal spaces were significantly more exposed to radiation at not only measurement side but also the surgical field, particularly when the number of CT scans was four.

CONCLUSION

We found that the patient's 5th to 8th intercostal space was the most radiation exposed area by intraoperative CBCT imaging because the CBCT movement was restricted by the patient's arm, anesthesia machine, and operating table during chest surgery. In future, it is strongly required to research for radiation protection in this area. Furthermore, performing no more than three scans intraoperatively may be preferable in order to protect patients from radiation exposure during CBCT guided thoracic surgery.

Technical Advances in Segmentectomy for Lung Cancer: A Minimally Invasive Strategy for Deep, Small, and Impalpable Tumors

With the increased detection of early-stage lung cancer and the technical advancement of minimally invasive surgery (MIS) in the field of thoracic surgery, lung segmentectomy using MIS, including video- and robot-assisted thoracic surgery, has been widely adopted. However, lung segmentectomy can be technically challenging for thoracic surgeons due to (1) complex segmental and subsegmental anatomy with frequent anomalies, and (2) difficulty in localizing deep, small, and impalpable tumors, leading to difficulty in obtaining adequate margins. In this review, we summarize the published evidence and discuss key issues related to MIS segmentectomy, focusing on preoperative planning/simulation and intraoperative tumor localization. We also demonstrate two of our techniques: (1) three-dimensional computed tomography (3DCT)-based resection planning using a novel 3DCT processing software, and (2) tumor localization using a novel radiofrequency identification technology.

Planting Seeds into the Lung: Image-Guided Percutaneous Localization to Guide Minimally Invasive Thoracic Surgery

Image-guided localization materials are constantly evolving, providing options for the localization of small pulmonary nodules to guide minimally invasive thoracic surgery. Several preoperative methods have been developed to localize small pulmonary lesions prior to video-assisted thoracic surgery. These localization techniques can be categorized into 4 groups according to the materials used: localization with metallic materials (hook-wire, microcoil, or spiral coil), localization with dye (methylene blue or indigo carmine), localization with contrast agents (lipiodol, barium, or iodine contrast agents), and radiotracers (technetium-99m). However, the optimal localization method has not yet been established. In this review article, we discuss the various localization techniques and the advantages and disadvantages of localization techniques as well as the available safety and efficacy data on these techniques.

Navigation Bronchoscopy

With the advent of lung cancer screening, and the increasingly frequent use of computed tomography (CT) scanning for investigating non-pulmonary pathology (for example CT coronary angiogram), the number of pulmonary nodules requiring further investigation has risen significantly. Most of these nodules are found in the lung periphery, which presents challenges to biopsy, and many centers rely on trans-thoracic needle biopsy performed under image guidance by radiologists. However, the desire to minimize complications is driving the development of increasingly accurate navigation bronchoscopy platforms, something that will be crucial in the new era of bronchoscopic therapeutics for lung cancer. This review describes these platforms, summarizes the current evidence for their use, and takes a look at future developments.

Placement of markers to assist minimally invasive resection of peripheral lung lesions

With development of lung cancer screening programs and increased utilization of radiographic imaging there is significantly higher detection of smaller lung nodules and subsolid lesions. These nodules could be malignant and pose a diagnostic challenge. Video-assisted thoracoscopic surgery and robotic-assisted thoracoscopic surgery (RATS) represent minimally invasive methods for tissue sampling. Intraoperative identification of these lesions maybe difficult, requiring marking prior to surgery. We review different techniques for the placement of markers to assist in the resection of peripheral lung lesions (PLL).

Virtual-assisted lung mapping (VAL-MAP) shortened surgical time of wedge resection

Background

The detection of extremely small lung tumors has increased with the development of computed tomography. Resection of such tumors by thoracoscopy is often hindered due to the unclear location of the tumor. Various methods of preoperative determination of such lesions have been attempted, but without marked success. Here we used virtual-assisted lung mapping (VAL-MAP) to perform surgical resection of small lung lesions.

Methods

We selected patients with pulmonary tumors that we anticipated to be difficult to identify during thoracoscopy and/or decide the resection line for sub-lobar lung resection. The wedge resections in the VAL-MAP group were compared to a group of patients who underwent wedge resection without VAL-MAP in 2013.

Results

Surgery duration was significantly shorter in the VAL-MAP group (average: 76.4 min) than in the 2013 group (average: 108.6 min; P=0.000451), although the VAL-MAP group (average major axis: 9.6 mm) had smaller tumors (P=0.000032) and more pure ground-glass opacities (GGOs) (P=0.0000919) than the 2013 group (average major axis: 16.6 mm).

Conclusions

The findings of this study indicate that VAL-MAP is efficacious. In particular, VAL-MAP resulted in a shorter surgery duration and has expanded the indications of resectable lesions.

Virtual bronchoscopic navigation without X-ray fluoroscopy to diagnose peripheral pulmonary lesions: a randomized trial

Background

Transbronchial biopsy for peripheral pulmonary lesions is generally performed under X-ray fluoroscopy. Virtual bronchoscopic navigation (VBN) is a method in which virtual images of the bronchial route to the lesion are produced based on CT images obtained before VBN, and the bronchoscope is guided using these virtual images, improving the diagnostic yield of peripheral pulmonary lesions. VBN has the possibility of eliminating the need for X-ray fluoroscopy in the bronchoscopic diagnosis of peripheral lesions. To determine whether VBN can be a substitute for X-ray fluoroscopy, a randomized multicenter trial (non-inferiority trial) was performed in VBN and X-ray fluoroscopy (XRF) -assisted groups.

Methods

The non-inferiority margin in the VBN-assisted group compared with the XRF-assisted group was set at 15%. The subjects consisted of 140 patients with peripheral pulmonary lesions with a mean diameter > 3 cm. In the VBN-assisted group, the bronchoscope was guided to the lesion using a VBN system without X-ray fluoroscopy. In the XRF-assisted group, the same bronchoscope was guided to the lesion under X-ray fluoroscopy. Subsequently, in both groups, the lesion was visualized using endobronchial ultrasonography with a guide sheath (EBUS/GS), and biopsy was performed. In this serial procedure, X-ray fluoroscopy was not used in the VBNA group.

Results

The subjects of analysis consisted of 129 patients. The diagnostic yield was 76.9% (50/65) in the VBN-assisted group and 85.9% (55/64) in the XRF-assisted group. The difference in the diagnostic yield between the two groups was -9.0% (95% confidence interval: -22.3% ~ 4.3%). The non-inferiority of the VBN-assisted group could not be confirmed. The rate of visualizing lesions by EBUS was 95.4% (62/65) in the VBN-assisted group and 96.9% (62/64) in the XRF-assisted group, being high in both groups.

Conclusions

On EBUS/GS, a bronchoscope and biopsy instruments may be guided to the lesions using VBN without X-ray fluoroscopy, but X-ray fluoroscopy is necessary to improve the accuracy of sample collection from lesions. During transbronchial biopsy for peripheral pulmonary lesions, VBN cannot be a substitute for X-ray fluoroscopy.

Trial registration

UMIN-CTR (UMIN000001710); registered 16 February 2009.

Role of post-mapping computed tomography in virtual-assisted lung mapping

Background Virtual-assisted lung mapping is a novel bronchoscopic preoperative lung marking technique in which virtual bronchoscopy is used to predict the locations of multiple dye markings. Post-mapping computed tomography is performed to confirm the locations of the actual markings. This study aimed to examine the accuracy of marking locations predicted by virtual bronchoscopy and elucidate the role of post-mapping computed tomography. Methods Automated and manual virtual bronchoscopy was used to predict marking locations. After bronchoscopic dye marking under local anesthesia, computed tomography was performed to confirm the actual marking locations before surgery. Discrepancies between marking locations predicted by the different methods and the actual markings were examined on computed tomography images. Forty-three markings in 11 patients were analyzed. Results The average difference between the predicted and actual marking locations was 30 mm. There was no significant difference between the latest version of the automated virtual bronchoscopy system (30.7 ± 17.2 mm) and manual virtual bronchoscopy (29.8 ± 19.1 mm). The difference was significantly greater in the upper vs. lower lobes (37.1 ± 20.1 vs. 23.0 ± 6.8 mm, for automated virtual bronchoscopy; p < 0.01). Despite this discrepancy, all targeted lesions were successfully resected using 3-dimensional image guidance based on post-mapping computed tomography reflecting the actual marking locations. Conclusions Markings predicted by virtual bronchoscopy were dislocated from the actual markings by an average of 3 cm. However, surgery was accurately performed using post-mapping computed tomography guidance, demonstrating the indispensable role of post-mapping computed tomography in virtual-assisted lung mapping.

Localizing small lung lesions in video-assisted thoracoscopic surgery via radiofrequency identification marking

BACKGROUND

To facilitate accurate localization of small lung lesions in thoracoscopic surgery, we employed a micro-radiofrequency identification tag designed to be delivered through the 2-mm working channel of a flexible bronchoscope. This report presents the results of preclinical studies of our novel localizing technique in a canine model.

METHODS

To evaluate functional placement, three types of tags [Group A, tag alone (n = 18); Group B, tag + resin anchor (n = 15); and Group C, tag + NiTi coil anchor (n = 15)] were bronchoscopically placed in subpleural areas and subsegmental bronchi via our new delivery device; tags were examined radiographically on days 0-7 and day 14. In addition, eight tags, which were placed at a mean depth of 13.3 mm (range 9-15.7 mm) from visceral pleura in bronchi with a mean diameter of 1.46 mm (range 0.9-2.3 mm), were recovered by partial lung resection under video-assisted thoracoscopic surgery using a 13.56-MHz wand-shaped probe with a 30-mm communication range.

RESULTS

Peripheral airway placement: Group C had a significantly higher retention rate than the other two groups (retention rate at day 14: Group A, 11.1 %; Group B, 26.7 %; Group C, 100.0 %; P < 0.0001). Central airway placement: Overall retention rate was 73.3 % in Group C, and placement was possible in bronchi of up to 3.3 mm in diameter. Outcomes of partial resection: Tag recovery rate was 100 %, mean time required for tag detection was 10.8 s (range 8-15 s), and mean surgical margin from the delivered tag was 9.13 mm (range 6-13 mm).

CONCLUSION

Radiofrequency identification marking enabled accurate localization with depth, which could ensure effective deep resection margins.

Techniques of stapler-based navigational thoracoscopic segmentectomy using virtual assisted lung mapping (VAL-MAP)

Anatomical segmentectomies play an important role in oncological lung resection, particularly for ground-glass types of primary lung cancers. This operation can also be applied to metastatic lung tumors deep in the lung. Virtual assisted lung mapping (VAL-MAP) is a novel technique that allows for bronchoscopic multi-spot dye markings to provide "geometric information" to the lung surface, using three-dimensional virtual images. In addition to wedge resections, VAL-MAP has been found to be useful in thoracoscopic segmentectomies, particularly complex segmentectomies, such as combined subsegmentectomies or extended segmentectomies. There are five steps in VAL-MAP-assisted segmentectomies: (I) "standing" stitches along the resection lines; (II) cleaning hilar anatomy; (III) confirming hilar anatomy; (IV) going 1 cm deeper; (V) step-by-step stapling technique. Depending on the anatomy, segmentectomies can be classified into linear (lingular, S6, S2), V- or U-shaped (right S1, left S3, S2b + S3a), and three dimensional (S7, S8, S9, S10) segmentectomies. Particularly three dimensional segmentectomies are challenging in the complexity of stapling techniques. This review focuses on how VAL-MAP can be utilized in segmentectomy, and how this technique can assist the stapling process in even the most challenging ones.

Localization of nonpalpable pulmonary nodules using CT-guided needle puncture

Background

Surgical resection of small pulmonary nodule is challenging via thoracoscopic procedure. We describe our experience of computed tomography (CT)-guided needle puncture localization of indeterminate pulmonary nodules prior to video-assisted thoracoscopic surgery (VATS).

Methods

From January 2011 to July 2014, 78 consecutive patients underwent CT-guided marking for the localization of 91 small pulmonary nodules. We retrospectively reviewed the clinical data, technical details, surgical findings and pathologic results, and complications associated with CT-guided localization.

Results

Seventy-eight consecutive patients (36 men and 42 women) underwent CT-guided marking localization of 91 indeterminate pulmonary nodules (62 pure ground-glass opacity nodules, 27 part-solid nodules, and 2 solid nodules). The mean size of the nodules was 8.6 mm (3.0–23.0 mm). The mean pleural distance between the nodule and lung surface was 11.5 mm (3.0–31.3 mm). The mean procedure time of CT-guided localization was 15.2 min (8–42 min). All patients stood the procedures well without requiring conversion to open thoracotomy. Twenty-four patients (30.77 %) developed pneumothorax after the procedures. Only one patient required retention of the puncture needle introducer for air drainage. The mean visual assessment pain score was 1.7 (0–3). Fifty-seven nodules (62.63 %) were confirmed as malignances, including 45 primary lung cancer, and 34 nodules (37.37 %) were confirmed as benign lesions.

Conclusions

CT-guided needle puncture can be an effective and safe procedure prior to VATS, enabling accurate resection and diagnosis of small pulmonary nodules.

Video-Assisted Thoracoscopic Surgery after Preoperative CT-Guided Lipiodol Marking of Small or Impalpable Pulmonary Nodules

PURPOSE

Small pulmonary lesions that include ground-glass attenuation have been increasingly discovered because of progressive imaging diagnostic technologies. Despite the detection of such small lesions, sometimes it is quite difficult to localize them because of their size or considerable depth from the visceral pleura. In the present study, we examined the usefulness of computed tomography-guided lipiodol marking for thoracoscopic resection of impalpable pulmonary nodules.

METHODS

Fifty-six patients with an undiagnosed peripheral lesion(s) of the lung who had undergone preoperative computed tomography-guided lipiodol marking followed by video-assisted thoracoscopic surgery were studied.

RESULTS

All of the nodules were successfully marked by computed tomography-guided lipiodol marking, and all except for one case were localized by means of intraoperative fluoroscopy as clear spots. With regard to complications, pneumothorax occurred in 21 patients (37.5%), and only one patient required transient drainage. Although hemorrhaging in the lung parenchyma and hemosputum occurred in nine patients (16.1%) and one patient (1.8%), respectively, no patients were in serious condition. No intra- or postoperative mortality or morbidity was observed.

CONCLUSION

Preoperative computed tomography-guided lipiodol marking of small or impalpable pulmonary nodules is a safe and useful procedure for thoracoscopic resection of the lung.

Virtual bronchoscopic navigation for peripheral pulmonary lesions

Virtual bronchoscopic navigation (VBN) is a method in which the bronchoscope is guided on the bronchial route to a peripheral lesion using virtual bronchoscopic images. In reports on VBN for peripheral pulmonary lesions searched in PubMed as of November 2013, the diagnostic yield by ultrathin bronchoscopy in combination with computed tomography and VBN was within the range of 65.4-81.6%. Using endobronchial ultrasonography with a guide sheath (EBUS-GS) and VBN, it was between 63.3 and 84.4%, and using X-ray fluoroscopy and VBN, it was between 62.5 and 78.7%. The overall diagnostic yield was 73.8% [95% confidence interval (CI) 70.9-76.8%] and that for lesions ≤ 2 cm was 67.4% (95% CI 63.3-71.5%). These values indicate high diagnostic rates. In randomized comparative trials, the combination of VBN with EBUS-GS improved the diagnostic yield and shortened the examination time. The diagnostic yields for lesions in the right upper lobe, those invisible on posterior-anterior radiographs and those located in the peripheral third of the lung field were improved by VBN on ultrathin bronchoscopy in combination with X-ray fluoroscopy. The usefulness of VBN was also found on meta-analysis. Taken together, VBN is a promising navigational bronchoscopy method as it requires no specific training, has a low overall complication rate of 1.0% (95% CI 0.2-1.8%) and does not directly induce or cause severe complications. To maximize the full potential of VBN and promote its use, investigation of cases in which it is useful, determination of the optimum combination of procedures, a cost/benefit analysis and advancement of the VBN system are warranted.

Diagnostic bronchoscopy--current and future perspectives

Lung cancer is the leading cause of cancer-related mortality worldwide. Standard bronchoscopy has limited ability to accurately localise and biopsy pulmonary lesions that cannot be directly visualised. The field of advanced diagnostic bronchoscopy is rapidly evolving due to advances in electronics and miniaturisation. Bronchoscopes with smaller outer working diameters, coupled with miniature radial and convex ultrasound probes, allow accurate central and peripheral pulmonary lesion localisation and biopsy while at the same time avoiding vascular structures. Increases in computational processing power allow three-dimensional reconstruction of computed tomographic raw data to enable virtual bronchoscopy (VB), providing the bronchoscopist with a preview of the bronchoscopy prior to the procedure. Navigational bronchoscopy enables targeting of peripheral pulmonary lesions (PPLs) via a "roadmap", similar to in-car global positioning systems. Analysis of lesions on a cellular level is now possible with techniques such as optical coherence tomography (OCT) and confocal microscopy (CM). All these tools will hopefully allow earlier and safer lung cancer diagnosis and in turn better patient outcomes. This article describes these new bronchoscopic techniques and reviews the relevant literature.

Video-assisted thoracoscopic surgery using mobile computed tomography: new method for locating of small lung nodules

BACKGROUND

The O-arm is an intraoperative imaging device that can provide computed tomography images. Surgery for small lung tumors was performed based on intraoperative computed tomography images obtained using the O-arm. This study evaluated the usefulness of the O-arm in thoracic surgery.

METHODS

From July 2013 to November 2013, 10 patients with small lung nodules or ground glass nodules underwent video-assisted thoracoscopic surgery using the O-arm. A needle was placed on the visceral pleura near the nodules. After the lung was re-expanded, intraoperative computed tomography was performed using the O-arm. Then, the positional relationship between the needle marking and the tumor was recognized based on the intraoperative computed tomography images, and lung resection was performed.

RESULTS

In 9 patients, the tumor could be seen on intraoperative computed tomography images using the O-arm. In 1 patient with a ground glass nodule, the lesion could not be seen, but its location could be inferred by comparison between preoperative and intraoperative computed tomography images. In only 1 patient with a ground glass nodule, a pathological complete resection was not performed. There were no complications related to the use of the O-arm.

CONCLUSIONS

The O-arm may be an additional tool to facilitate intraoperative localization and surgical resection of non-palpable lung lesions.

Thoracoscopic wedge lung resection using virtual-assisted lung mapping

Background

Virtual-assisted lung mapping is a novel bronchoscopic preoperative lung marking technique using virtual images to conduct multiple concurrent lung markings with dye. This study analyzed the indications, mapping design, and outcomes of lung wedge resection using virtual-assisted lung mapping.

Methods

From August 2012 to October 2013, 35 patients with 59 lesions were planned to undergo thoracoscopic lung wedge resection aided by virtual-assisted lung mapping. The data related to virtual-assisted lung mapping were prospectively collected, with the exception of the mapping design which was retrospectively analyzed.

Results

Suspected primary lung cancer (21 lesions in 18 patients) and metastatic lung tumors (38 lesions in 17 patients) were treated by thoracoscopic lung wedge resection with the aid of virtual-assisted lung mapping; 50 wedge resections were conducted with 107 markings. Virtual-assisted lung mapping was most frequently designed to place 2 ( n = 15 wedge resections) or 3 ( n = 17) markings to both identify the tumor(s) and secure a sufficient resection margin. In 7 wedge resections, anatomical landmarks and/or imaginary auxiliary lines functioned as complementary parts of the lung map when bronchial anatomy did not allow for markings at ideal spots. The resection outcomes were satisfactory without clinically evident complications.

Conclusion

Multiple markings of virtual-assisted lung mapping not only enabled tumor identification, but also secured sufficient resection margins. Special techniques using anatomical landmarks and imaginary auxiliary lines were complementary to the lung map when bronchial anatomy did not allow for markings at ideal spots.

Use of virtual assisted lung mapping (VAL-MAP), a bronchoscopic multispot dye-marking technique using virtual images, for precise navigation of thoracoscopic sublobar lung resection

OBJECTIVE

We have developed a novel bronchoscopic multiple marking technique to assist resection of hardly palpable lung tumors. Because 3-dimensional virtual images were used and multiple markings made on the lung surface to provide "geometric" information, we termed this technique "virtual assisted lung mapping" (VAL-MAP). The safety and efficacy of VAL-MAP were evaluated.

METHODS

Virtual bronchoscopy was used to select 2 to 4 appropriate bronchial branches for marking. Bronchoscopy was conducted with the patient under local anesthesia. A metal-tip catheter was inserted into a selected bronchus and advanced to the pleura. The location of the catheter tip was fluoroscopically confirmed, and 1 mL of indigo carmine was injected. This procedure was repeated to complete all the planned markings. Post-VAL-MAP computed tomography was used to visualize the localization of the multiple markings on 3-dimensional virtual images, which were used as references in the subsequent operation.

RESULTS

Of the 95 marking attempts made for 37 tumors in 30 patients, 88 (92.6%) were identified and contributed to the surgery. No clinically evident complications were associated with the procedure. A total of 15 wedge resections and 18 segmentectomies were thoracoscopically conducted, with a successful resection rate of 100%. Multiple markings of the VAL-MAP were complementary, enabling us to achieve complete resection even when 1 of the markings failed. The markings were visible even on interlobar fissures, at the apex, and on the diaphragm, which conventional percutaneous marking can hardly reach.

CONCLUSIONS

VAL-MAP was safely conducted with satisfactory outcomes in our early experience. Additional confirmation of its safety and efficacy is necessary.

Newer modalities in the work-up of peripheral pulmonary nodules

Technological advances in recent years have translated into the availability of newer modalities to establish the cause of peripheral pulmonary nodules (PPN). Even though the verdict is still out on the ideal diagnostic modality, there is no doubt that the bronchoscope is becoming a popular tool in the armamentarium of physicians who deal with PPN. This article focuses on newer bronchoscopic modalities being studied for the work-up of PPN. The authors also summarize the value of established diagnostic modalities to provide a balanced perspective.

CT-guided percutaneous transthoracic localization of pulmonary nodules prior to video-assisted thoracoscopic surgery using barium suspension

Objective

To describe our initial experience with CT-guided percutaneous barium marking for the localization of small pulmonary nodules prior to video-assisted thoracoscopic surgery (VATS).

Materials and Methods

From October 2010 to April 2011, 10 consecutive patients (4 men and 6 women; mean age, 60 years) underwent CT-guided percutaneous barium marking for the localization of 10 small pulmonary nodules (mean size, 7.6 mm; range, 3-14 mm): 6 pure ground-glass nodules, 3 part-solid nodules, and 1 solid nodule. A 140% barium sulfate suspension (mean amount, 0.2 mL; range, 0.15-0.25 mL) was injected around the nodules with a 21-gauge needle. The technical details, surgical findings and pathologic features associated with barium localizations were evaluated.

Results

All nodules were marked within 3 mm (mean distance, 1.1 mm; range, 0-3 mm) from the barium ball (mean diameter, 9.6 mm; range, 8-16 mm) formed by the injected barium suspension. Pneumothorax occurred in two cases, for which one needed aspiration. However, there were no other complications. All barium balls were palpable during VATS and visible on intraoperative fluoroscopy, and were completely resected. Both the whitish barium balls and target nodules were identifiable in the frozen specimens. Pathology revealed one invasive adenocarcinoma, five adenocarcinoma-in-situ, two atypical adenomatous hyperplasias, and two benign lesions. In all cases, there were acute inflammations around the barium balls which did not hamper the histological diagnosis of the nodules.

Conclusion

CT-guided percutaneous barium marking can be an effective, convenient and safe pre-operative localization procedure prior to VATS, enabling accurate resection and diagnosis of small or faint pulmonary nodules.

LungPoint--a new approach to peripheral lesions

INTRODUCTION

Although flexible bronchoscopy is the least invasive procedure for sampling, it is limited by its inability to reach lesions in the peripheral segments of the lung. Biopsy success is further compromised if the lesion is less than 30 mm in diameter or cannot be seen on fluoroscopy. We wanted to explore whether a new bronchoscopic navigation system could help access the peripheral lung airways and enable lesion sampling.

METHODS

The LungPoint system produced a virtual bronchoscopic pathway indicating the bronchus into which the bronchoscope should be advanced. Virtual bronchoscopic images were displayed alongside and registered with actual bronchoscopic video. After performing broncoscopy with a standard bronchoscope for first examination, the thin bronchoscope was advanced to the target bronchus under direct visualization without fluoroscopy. A pilot study included consecutive patients at a tertiary teaching hospital with pulmonary peripheral lesions (<42 mm). Biopsies were taken later.

RESULTS

Study subjects included 25 patients (9 women and 16 men, mean age 67 years) with 25 lesions (mean size 28 mm). Using this navigation system, the bronchoscope could be advanced along the planned route in all cases. In 14 of the cases (56%), the bronchoscope could be advanced all the way to the lesion bronchus. The planning time was a median of 5 minutes, and the median examination time was 15 minutes. A definitive diagnosis was possible in 20 cases (80%). One patient experienced a small pneumothorax because of the biopsy that resolved without drainage. No other complications occurred.

CONCLUSIONS

This navigation system is useful for bronchoscopy for pulmonary peripheral lesions (NCT01067755).

3D MDCT-based system for planning peripheral bronchoscopic procedures

The diagnosis and staging of lung cancer often begins with the assessment of a suspect peripheral chest site. Such suspicious peripheral sites may be solitary pulmonary nodules or other abnormally appearing regions of interest (ROIs). The state-of-the-art process for assessing such peripheral ROIs involves off-line procedure planning using a three-dimensional (3D) multidetector computed tomography (MDCT) chest scan followed by bronchoscopy with an ultrathin bronchoscope. We present an integrated computer-based system for planning peripheral bronchoscopic procedures. The system takes a 3D MDCT chest image as input and performs nearly all operations automatically. The only interaction required by the physician is the selection of ROI locations. The system is computationally efficient and fits smoothly within the clinical work flow. Integrated into the system and described in detail in the paper is a new surface-definition method, which is vital for effective analysis and planning to peripheral sites. Results demonstrate the efficacy of the system and its usage for the live guidance of ultrathin bronchoscopy to the periphery.

3D CT-video fusion for image-guided bronchoscopy

Bronchoscopic biopsy of the central-chest lymph nodes is an important step for lung-cancer staging. Before bronchoscopy, the physician first visually assesses a patient's three-dimensional (3D) computed tomography (CT) chest scan to identify suspect lymph-node sites. Next, during bronchoscopy, the physician guides the bronchoscope to each desired lymph-node site. Unfortunately, the physician has no link between the 3D CT image data and the live video stream provided during bronchoscopy. Thus, the physician must essentially perform biopsy blindly, and the skill levels between different physicians differ greatly. We describe an approach that enables synergistic fusion between the 3D CT data and the bronchoscopic video. Both the integrated planning and guidance system and the internal CT-video registration and fusion methods are described. Phantom, animal, and human studies illustrate the efficacy of the methods.

Diagnosis of peripheral pulmonary lesions using a bronchoscope insertion guidance system combined with endobronchial ultrasonography with a guide sheath

We developed a bronchoscope insertion guidance system that produces virtual images by extracting the bronchi by automatic threshold adjustment, and searching for the bronchial route to the determined target. We used this system in combination with a thin bronchoscope and endobronchial ultrasonography with a guide sheath (EBUS-GS), and evaluated its practicability, usefulness and safety. The subjects were 31 patients with 32 peripheral pulmonary lesions. Computed tomography (CT) data were transferred into this system, and virtual bronchial images were automatically produced by setting the lesion as the target. While virtual images with the target were displayed for comparison with real images by the system, a thin bronchoscope was advanced to the target bronchus. Transbronchial biopsy (TBB) was then performed by EBUS-GS. The system automatically produced virtual images to a median of fifth- (third- to seventh-) order bronchi. In all patients, the thin bronchoscope could be guided along the planned route, and observation to a median of fifth- (third- to seventh-) order bronchi was possible. Thirty lesions (93.8%) were successfully visualized by EBUS, and 27 (84.4%) could be pathologically diagnosed. In lesions < or =30mm in size, the EBUS visualization yield was 91.7% (22/24), and the diagnostic yield was 79.2% (19/24). The median total examination time was 22.3 (9.8-41.5) min. In summary, using the bronchoscope insertion guidance system, virtual images can be readily produced, and the bronchoscope can be successfully guided to the target. This method is promising as a routine examination method in the biopsy of peripheral pulmonary lesions.

Virtual Mediastinoscopy for Safer and More Accurate Mediastinal Exploration

PURPOSE

Virtual endoscopy can theoretically produce images of hollow organs from computed tomographic scanning by discriminating walls with the air space. We produced virtual images of the mediastinum (ie, virtual mediastinoscopy based on positron emission tomography and computed tomography scanning data to visualize lymph nodes and great vessels similar to cervical mediastinoscopy).

DESCRIPTION

Virtual images from 5 patients with positive mediastinal positron emission tomography findings were produced using computer software designed for virtual endoscopy. Visualization of lymph nodes and vessels was done based on positron emission tomography-computed tomography and enhanced computed tomographic scanning data, respectively.

EVALUATION

Virtual mediastinoscopy clearly showed three-dimensional relationships between active nodes and surrounding structures. Great vessels, such as the innominate artery and azygos vein, which require assessment during a mediastinoscopy, were visualized in virtual movies. Further, perspective views in the craniocaudal direction based on surgeon-orientation, simulated actual views were obtained during cervical video mediastinoscopy.

CONCLUSIONS

Virtual mediastinoscopy provided realistic images of the mediastinal anatomy, and has the potential to make cervical mediastinoscopy and other mediastinal explorations safer, as well as more accurate.

A virtual bronchoscopic navigation system for pulmonary peripheral lesions

STUDY OBJECTIVES

We performed ultrathin bronchoscopy for pulmonary peripheral lesions using a system that displays virtual bronchoscopy (VB) images to the lesion simultaneously with actual images and navigates the bronchoscope to the target bronchus. We then evaluated the system with regard to its usefulness and problems.

DESIGN

A pilot study.

SETTING

A tertiary teaching hospital.

PATIENTS

The subjects were consecutive patients with small pulmonary peripheral lesions (< or = 30 mm).

INTERVENTIONS

Using this system, the rotation, advancement, and retreat of VB images were possible, and the bronchus into which the bronchoscope was to be advanced was displayed. VB images were displayed along with actual images, and the ultrathin bronchoscope was advanced to the target bronchus under direct vision. Under CT and radiographic fluoroscopy, a pair of forceps was inserted into the lesion via the bronchoscope. Thin-section CT images were obtained; after confirming the advancement of the bronchoscope into the target bronchus and the arrival of the forceps at the lesion, a biopsy was performed.

RESULTS

Study subjects included 37 patients with 38 lesions. VB images to a median of the sixth- (third- to ninth-) order bronchi could be produced. Using this system, the ultrathin bronchoscope could be advanced into the planned route for 36 of the 38 lesions (94.7%). The system was used for a median of 2.6 min, and the median examination time was 24.9 min. The biopsy forceps could be advanced to the lesion in 33 of the 38 lesions (86.8%), and diagnosis was possible for 31 lesions (81.6%).

CONCLUSIONS

This navigation system is useful for ultrathin bronchoscopy for pulmonary peripheral lesions.

Usefulness and complications of computed tomography-guided lipiodol marking for fluoroscopy-assisted thoracoscopic resection of small pulmonary nodules: Experience with 174 nodules

OBJECTIVE

Several techniques have been reported for the localization of small pulmonary nodules in thoracoscopic resection. In the present study we examined the usefulness and complications of computed tomography-guided lipiodol marking for thoracoscopic resection in our experience of 174 nodules.

METHODS

Computed tomography-guided lipiodol marking was performed on 174 nodules less than 30 mm in size. Of these nodules, 45 showed ground-glass opacity images and 129 showed solid images on computed tomography. The mean size of the nodules was 10 +/- 6 mm (range, 2-30 mm), and their mean depth from the pleural surface was 10 +/- 7 mm (range, 0-30 mm). One to 7 days before thoracoscopy, all of the nodules were marked with 0.4 to 0.5 mL of lipiodol by using computed tomography. The marked nodules were grasped with a ring-shaped forceps during fluoroscopy and resected by means of thoracoscopy.

RESULTS

All the nodules could be marked and localized by means of fluoroscopy as a clear spot during thoracoscopic surgery. Complications of the marking were chest pain requiring analgesia in 16 (11%) patients, hemosputum in 11 (6%) patients, pneumothorax in 30 (17%) patients, and hemopneumothorax in 1 (0.6%) patient. Eleven (6%) patients with pneumothorax required drainage, and the patient with hemopneumothorax required an emergency operation. No other complications were observed.

CONCLUSION

Lipiodol marking is a useful, safe, and inexpensive procedure for localizing ground-glass opacity lesions, small pulmonary nodules, or both for thoracoscopic resection.