CT-Guided Percutaneous Transthoracic Needle Biopsy Using the Additional Laser Guidance System by a Pulmonologist with 2 Years of Experience in CT-Guided Percutaneous Transthoracic Needle Biopsy

Min-Cheol Jeon; Ju Ock Kim; Sung Soo Jung; Hee Sun Park; Jeong Eun Lee; Jae Young Moon; Chae Uk Chung; Da Hyun Kang; Dong Il Park

doi:10.4046/trd.2017.0123

Tuberc Respir Dis > Volume 81(4); 2018 > Article

Jeon, Kim, Jung, Park, Lee, Moon, Chung, Kang, and Park: CT-Guided Percutaneous Transthoracic Needle Biopsy Using the Additional Laser Guidance System by a Pulmonologist with 2 Years of Experience in CT-Guided Percutaneous Transthoracic Needle Biopsy

Original Article

Tuberculosis and Respiratory Diseases 2018;81(4):330-338.

Published online: June 19, 2018

DOI: https://doi.org/10.4046/trd.2017.0123

CT-Guided Percutaneous Transthoracic Needle Biopsy Using the Additional Laser Guidance System by a Pulmonologist with 2 Years of Experience in CT-Guided Percutaneous Transthoracic Needle Biopsy

Min-Cheol Jeon, Ph.D.¹

, Ju Ock Kim, M.D., Ph.D.², Sung Soo Jung, M.D., Ph.D.², Hee Sun Park, M.D., Ph.D.², Jeong Eun Lee, M.D., Ph.D.², Jae Young Moon, M.D., Ph.D.², Chae Uk Chung, M.D., Ph.D.², Da Hyun Kang, M.D.², Dong Il Park, M.D.²

¹Department of Radiology, Daejeon Health Institute of Technology, Daejeon, Korea.

²Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea.

Address for correspondence: Dong Il Park, M.D. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Chungnam National University Hospital, 282 Munhwa-ro, Jung-gu, Daejeon 35015, Korea. Phone: 82-42-280-7147, Fax: 82-42-257-5753, rahm3s@gmail.com

Received December 03, 2017 Revised January 16, 2018 Accepted February 20, 2018

It is identical to the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/)

Abstract

Background

We developed an additional laser guidance system to improve the efficacy and safety of conventional computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB), and we conducted this study to evaluate the efficacy and safety of our system.

Methods

We retrospectively analyzed the medical records of 244 patients who underwent CT-guided PTNB using our additional laser guidance system from July 1, 2015, to January 20, 2016.

Results

There were nine false-negative results among the 238 total cases. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of our system for diagnosing malignancy were 94.4% (152/161), 100% (77/77), 100% (152/152), 89.5% (77/86), and 96.2% (229/238), respectively. The results of univariate analysis showed that the risk factors for a false-negative result were male sex (p=0.029), a final diagnosis of malignancy (p=0.033), a lesion in the lower lobe (p=0.035), shorter distance from the skin to the target lesion (p=0.003), and shorter distance from the pleura to the target lesion (p=0.006). The overall complication rate was 30.5% (74/243). Pneumothorax, hemoptysis, and hemothorax occurred in 21.8% (53/243), 9.1% (22/243), and 1.6% (4/243) of cases, respectively.

Conclusion

The additional laser guidance system might be a highly economical and efficient method to improve the diagnostic efficacy and safety of conventional CT-guided PTNB even if performed by inexperienced pulmonologists.

Keywords: Lasers; Solitary Pulmonary Nodule; Lung Neoplasms; Biopsy, Needle

Introduction

Conventional computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) is a well-established method and is the most common imaging modality used to obtain tissue from a lung lesion¹. Cone-beam CT (CBCT)-guided PTNB has recently been in the spotlight because of its real-time fluoroscopic capability, greater flexibility in orientating the detector around the patient, and relatively low radiation exposure compared with CT fluoroscopy-guided PTNB²^,3. The advantage of CBCT-guided PTNB over conventional CT-guided PTNB is its real-time properties that enable operators to avoid dangerous structures and access the target lesion in patients unable to cooperate with breath holding³. Lee et al.³ reported the outcomes of CBCT-guided PTNB in 1,108 patients. The results showed that the sensitivity, specificity, diagnostic accuracy, and incidence of complications (pneumothorax and hemoptysis) were 95.7% (733/766), 100% (323/323), 97.0% (1,056/1,089), and 23.9% (276/1,153), respectively. However, several studies on conventional CT-guided PTNB involving more than 100 patients have been reported since 2010, all of which showed similar results to those of CBCT-guided PTNB (sensitivities, 90%-96%; specificities, 92%-100%; diagnostic accuracies, 93%-97%)⁵^,6^,7^,8^,9^,10^,11. Choi et al.¹¹ performed conventional CT-guided PTNB on patients with pulmonary nodules <1 cm and reported a sensitivity, specificity, and diagnostic accuracy of 93.1% (148/159), 98.8% (81/82), and 95.0% (229/241), respectively. These results are comparable with those of a study that performed CBCT on pulmonary nodules ≤1 cm, in which the sensitivity, specificity, and diagnostic accuracy were 96.7% (58/60), 100% (38/38), and 98.0% (96/98), respectively¹². CBCT is very expensive and requires a large physical space for the equipment. Therefore, considering the diagnostic yield and patient safety of conventional CT reported in recent studies, which are comparable with those of CBCT, it is preferable to improve existing conventional CT-guided PTNB than to purchase a CBCT system¹^,2^,3^,4^,11^,12. We developed the additional laser guidance system to improve the efficacy and safety of conventional CT-guided PTNB. This study was conducted to evaluate the efficacy and safety of our laser guidance system.

Materials and methods

1. Patients

We performed a retrospective analysis of the medical records of 244 patients who underwent PTNB from July 1, 2015, to January 20, 2016. Approval for this study was given by the Chungnam National University Hospital Institutional Review Board (CNUH 2016-02-004), and requirement for informed consent was waived.

2. Procedures

1) Installation and alignment of the additional laser guidance system

The installation and alignment of the additional laser guidance system were as follows. (1) We mounted the laser level (HG-909A; X-CLOVE, China), which adhered to a wheel bracket, on a stainless steel frame and positioned it on the opposite side of the CT gantry (Figures 1, 2A). (2) By adjusting the wheel bracket (to the left or right), we matched both vertical laser beam lines, which came from the laser level (HG-909A; X-CLOVE) and the CT gantry (Figure 2B). (3) The second laser level, also mounted on an iron frame, was placed on the opposite side of the patient to the operator, perpendicular to the other laser (Figure 2C).

2) CT-guided PTNB procedure

All PTNBs were performed under CT (Siemens SOMATOM Sensation 64 CT scanner; Siemens Medical Solutions, Forchheim, Germany) guidance by one pulmonologist (D.I. Park with 2 years of experience in CT-guided PTNB). Before CT was initiated, the importance of breathing was explained to each patient, who was asked to practice breathing in at tidal volume and holding it three times. After obtaining a CT scout image, low-dose (100 kVp, 20 mA) CT was performed at the area of interest using a 2-mm section thickness and with the patient practicing breath-holding after inspiration. The subsequent procedures were as follows. (1) The skin entry site was determined by the CT gantry laser lights and radiopaque grid displayed on the skin and was sterilized using Betadine. (2) Local anesthesia from the skin to the pleural surfaces was administered using a 1% lidocaine solution. (3) By adjusting the laser position when the patient inhaled and held their breath, the intersection of the two laser lines originating from the head end and the side opposite to the operator was located at the entry point on the skin (Figure 3). In the case of an oblique approach, we used a digital level (DWL-80E; Sincon, China) to tilt the laser level (HG-909A; X-CLOVE) before performing procedure (Figure 2D). (4) A coaxial needle was inserted along the two laser lines into the target lesion via the skin entry site (Figure 3D). (5) A CT scan was conducted to ensure that the coaxial needle tip was in the correct position (Figure 4). (6) Then, a semi-automatic cutting needle ranging in size from 20 to 16 gauge (Stericut; TSK Laboratory, Tochigi, Japan) was inserted via the coaxial introducer, and the biopsy was performed. Specimen acquisition was repeated until a visually adequate amount of tissue was obtained. To check for biopsy-related complications, CT was performed after obtaining the tissue.

3. Statistical analysis

To determine the risk factors for diagnostic failure, the study population was divided into a diagnostic success group (i.e., true-positive and true-negative results) and a diagnostic failure group (i.e., false-positive and false-negative results). The factors related to diagnostic failure were evaluated by univariate analyses using the Mann-Whitney U test for numerical values and the chi-square test for categorical values. Statistical analysis was performed using PASW Statistics version 18.0 (IBM Corp., Armonk, NY, USA). A p-value of < 0.05 was considered to indicate statistical significance.

Results

1. Patient and target lesion characteristics

The baseline patient characteristics and procedures performed are summarized in Table 1 (n=244). The mean age of the patients was 66.5±11.3 years, and 64.8% (n=158) of all cases were male. Among all target lesions, 41.4% (n=101) were located in the lower lobes. The mean longest diameter was 33.8±20.1 mm. The numbers of solid, sub-solid, and groundglass lesions were 218 (89.3%), 14 (5.7%), and 12 (4.9%), respectively.

2. Procedure and radiation dose

During the procedure, 79 (32.4%) patients were placed in the supine position, 159 (65.2%) in the prone position, and six (2.4%) in the decubitus position; 58 (23.8%) 16-gauge biopsy needles, 136 (55.7%) 18-gauge needles, and 50 (20.5%) 20-gauge needles were used. The mean distance from the skin to the target lesion was 51.8±21.5 mm. The total procedure time was 8.8±2.9 minutes, and the needle dwelling time was 2.2±1.3 minutes. The number of biopsies performed was 2.2±1.2. The calculated mean effective radiation dose was 1.0±0.4 mSv.

3. Pathological results and final diagnoses

A lung lesion was recorded as ‘benign’ if the nodule met the following criteria. (1) The pathologic results showed definitive benign features (e.g., aspergilloma, tuberculosis). (2) The pathologic results did not show definitive benign features (e.g., inflammation, fibrosis); for example, (a) the CT findings favored a benign lesion, (b) the size of the lesion decreased or showed no interval change on follow-up CT after more than 18 months, or (c) the physician decided to discontinue follow-up because the lesion was regarded as benign. (3) The pathologic results confirmed the nodule as “benign” on more than two occasions. All lesions not determined to be benign or malignant were classified as “indeterminate” and were excluded from the statistical analysis.

Among the technically successful cases (n=243), 161 (66.3%), 77 (31.7%), and five (2.1%) were diagnosed as malignant, benign, and indeterminate lesions, respectively. Of the malignant lesions (n=161), 152 (94.4%) were diagnosed by PTNB. False-negative cases (n=9) were finally diagnosed as malignancy by re-PTNB (n=4), bronchoscopy (n=2), surgical biopsy (n=1), endobronchial ultrasound (n=1), and pleural effusion cytology (n=1). Of the 77 (31.7%) lesions diagnosed as benign, 32 (13.2%) had specific benign pathologic features, with the most common benign lesion being tuberculosis (n=16, 6.6%). There were five indeterminate cases. In the remaining technically successful cases, excluding the indeterminate cases, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy for the diagnosis of malignancy were 94.4% (152/161), 100% (77/77), 100% (152/152), 89.5% (77/86), and 96.2% (229/238), respectively. The pathologic results and final diagnoses of the malignant lesions are summarized in Table 2.

4. Risk factors for diagnostic failure

There were nine false-negative results among the 238 total cases. The results of the univariate analyses showed that the risk factors for a false-negative result were male sex (p=0.029), a final diagnosis of malignancy (p=0.033), a lesion in the lower lobe (p=0.035), and a shorter distance from the pleura to the target lesion (p=0.006). The longest diameter of the target lesion was not related to diagnostic failure (p=0.274) (Table 3).

5. Complications and management

The overall complication rate was 30.5% (74/243). Pneumothorax, hemoptysis, and hemothorax occurred in 21.8% (53/243), 9.1% (22/243), and 1.6% (4/243) of cases, respectively. In terms of pneumothorax management, aspiration by syringe (3.7%, 9/243) and chest tube drainage (5.3%, 13/243) were performed. All hemoptysis (n=22) and hemothorax (n=4) cases recovered after oxygen therapy and close observation.

Discussion

In this study, we performed CT-guided PTNB using the additional laser guidance system. Our additional laser guidance system facilitated the ideal trajectory angle of the coaxial needle though the skin and pleura. The results showed that the sensitivity, specificity, PPV, NPV, and diagnostic accuracy for the diagnosis of malignancy were 94.4% (152/161), 100% (77/77), 100% (152/152), 89.5% (77/86), and 96.2% (229/238), respectively.

These results are comparable with the outcomes² of the initial experience with CBCT-guided PTNB, performed in 71 patients with lung nodules ≤30 mm. The sensitivity, specificity, diagnostic accuracy, and incidence of complications in that study were 97% (35/36), 100% (25/25), 98.4% (60/61), and 38.0%, respectively.

In terms radiation exposure, the mean effective radiation dose in our study was 1.0±0.4 mSv. This is less than the 7.3 mSv and 4.6 mSv doses of CBCT reported by Lee et al.³ and Hwang et al.¹³, respectively, and is similar to the mean effective dose of the National Lung Screening Trial (1.4±0.5 mSv)¹⁴. The additional laser guidance system provides operators guidance and confidence regarding the correct insertion angle of the coaxial needle, thereby decreasing the time and number of adjustments to the needle location required to approach the target lesion. We believe that these factors can reduce radiation exposure.

Regarding diagnostic failure, there was one technical failure case and nine false-negative cases. The one technical failure was caused by a marking error (marking the left lung lesion as the right lung lesion) made by the radiologic technologist when determining the skin entry site, and this case was not included in the analysis of the diagnostic yield. In this study, male sex (p=0.029), a final diagnosis of malignancy (p=0.033), a lesion in the lower lobe (p=0.035), a shorter distance from the skin to the target lesion (p=0.003), and a shorter distance from the pleura to the target lesion (p=0.006) were significantly related to false-negative results. Our finding that a malignant final diagnosis was a risk factor for diagnostic failure corresponds to the results of previous studies⁸^,15. A lower lobe lesion is a well-known risk factor for diagnostic failure and is explained by the greater respiratory motion of the lower lobe during the procedure³^,8^,15. In several studies, male sex has been reported as a risk factor for pneumothorax and for diagnostic failure³^,8^,16. Known patient-related risk factors for pneumothorax, such as chronic obstructive pulmonary disease, emphysema, and a history of smoking, are more common in males¹⁷^,18.

Interestingly, our results showed that shorter distances from the pleura to the target lesion (p=0.006) were significantly related to diagnostic failure. In studies analyzing the relationship between the distance from the pleura to the target lesion and diagnostic failure, there was a tendency toward increased diagnostic failure if the lesion was too close or too distant from the pleura³^,15^,19. Ko et al.²⁰ reported that adjacent pleural disease is a risk factor for pneumothorax. Other studies found that the incidence of pneumothorax increases with decreasing distance between the lesion and pleura³^,21. Biopsy of lesions adjacent to the pleura is technically challenging, because it is very difficult to reposition the needle tip. We believe that pneumothorax and technical difficulty may have influenced our results.

In terms of complications, the rates of overall complications (30.5%, 74/243), pneumothorax (21.8%, 53/243), and hemoptysis (9.1%, 22/243) in the current study were comparable with those of other studies¹^,2^,3. The incidence of chest tube placement for pneumothorax was 5.3% (13/243).

There are several disadvantages of CBCT-guided PTNB compared with conventional CT-guided PTNB. First, the operator is exposed to radiation in CBCT-guided PTNB but not in conventional CT-guided PTNB. The radiation exposure to patients is much higher in CBCT-guided PTNB than in conventional CT-guided PTNB, especially when using the low-dose CT protocol²²^,23. Second, the image quality of CBCT is inferior to that of conventional CT²⁴^,25. In general, reduced image quality does not negatively affect patient safety or the accuracy of PTNB²³^,26. However, if the target lesion is adjacent to the mediastinum or main vessels or is surrounded by pleural effusion, an inferior resolution could affect patient safety and the diagnostic yield. Third, CBCT is very expensive and requires a large physical space for the equipment²⁷. Our laser guidance system, however, is extremely economical and requires approximately 200 USD to build.

One of the limitations of this study was its retrospective design, which is associated with unknown bias. The efficacy of our laser guidance system could have been underestimated as a result of patient selection bias, which is a crucial factor for PTNB results, especially considering that the operator was a pulmonologist with only 2 years of experience. Recently, we conducted a review of medical records to identify rejection cases from October 2016 to May 2017. Surprisingly, there were only seven out of 298 PTNB cases that were rejected for any reason. Another limitation was that we did not compare our method with that of conventional CT-guided PTNB or CBCT-guided PTNB directly. Prospective randomized controlled trials with specific enrollment criteria are needed to determine the efficacy and safety of our method.

In conclusion, the additional laser guidance system might be a highly economical and efficient method to improve the diagnostic efficacy and safety of conventional CT-guided PTNB even performed by a pulmonologist (2 years of experience) who is unexperienced.

Notes

Authors' Contributions: Conceptualization: Park DI, Jeon MC. Methodology: Park DI, Jeon MC. Formal analysis: Park DI, Jeon MC. Data curation: Park DI, Jeon MC. Software: Park DI, Jeon MC. Validation: Kim JO, Jung SS, Park HS, Lee JE, Moon JY, Chung CU, Kang DH. Writing - original draft preparation: Park DI, Jeon MC. Writing - review and editing: Kim JO, Jung SS, Park HS, Lee JE, Moon JY, Chung CU, Kang DH. Approval of final manuscript: all authors.

Conflicts of Interest: No potential conflict of interest relevant to this article was reported.

References

1. DiBardino DM, Yarmus LB, Semaan RW. Transthoracic needle biopsy of the lung. J Thorac Dis 2015;7(Suppl 4):S304-S316. PMID: 26807279.

2. Jin KN, Park CM, Goo JM, Lee HJ, Lee Y, Kim JI, et al. Initial experience of percutaneous transthoracic needle biopsy of lung nodules using C-arm cone-beam CT systems. Eur Radiol 2010;20:2108-2115. PMID: 20393715.

3. Lee SM, Park CM, Lee KH, Bahn YE, Kim JI, Goo JM. C-arm cone-beam CT-guided percutaneous transthoracic needle biopsy of lung nodules: clinical experience in 1108 patients. Radiology 2014;271:291-300. PMID: 24475839.

4. Yan GW, Bhetuwal A, Yan GW, Sun QQ, Niu XK, Zhou Y, et al. A systematic review and meta-analysis of C-arm cone-beam CT-guided percutaneous transthoracic needle biopsy of lung nodules. Pol J Radiol 2017;82:152-160. PMID: 28392852.

5. Zhuang YP, Wang HY, Zhang J, Feng Y, Zhang L. Diagnostic accuracy and safety of CT-guided fine needle aspiration biopsy in cavitary pulmonary lesions. Eur J Radiol 2013;82:182-186. PMID: 23079048.

6. Li Y, Du Y, Yang HF, Yu JH, Xu XX. CT-guided percutaneous core needle biopsy for small (≤20 mm) pulmonary lesions. Clin Radiol 2013;68:e43-e48. PMID: 23177650.

7. Loh SE, Wu DD, Venkatesh SK, Ong CK, Liu E, Seto KY, et al. CT-guided thoracic biopsy: evaluating diagnostic yield and complications. Ann Acad Med Singapore 2013;42:285-290. PMID: 23842769.

8. Takeshita J, Masago K, Kato R, Hata A, Kaji R, Fujita S, et al. CT-guided fine-needle aspiration and core needle biopsies of pulmonary lesions: a single-center experience with 750 biopsies in Japan. AJR Am J Roentgenol 2015;204:29-34. PMID: 25539234.

9. Yang W, Sun W, Li Q, Yao Y, Lv T, Zeng J, et al. Diagnostic accuracy of CT-guided transthoracic needle biopsy for solitary pulmonary nodules. PLoS One 2015;10:e0131373. PMID: 26110775.

10. Yaffe D, Koslow M, Haskiya H, Shitrit D. A novel technique for CT-guided transthoracic biopsy of lung lesions: improved biopsy accuracy and safety. Eur Radiol 2015;25:3354-3360. PMID: 25903714.

11. Choi SH, Chae EJ, Kim JE, Kim EY, Oh SY, Hwang HJ, et al. Percutaneous CT-guided aspiration and core biopsy of pulmonary nodules smaller than 1 cm: analysis of outcomes of 305 procedures from a tertiary referral center. AJR Am J Roentgenol 2013;201:964-970. PMID: 24147465.

12. Choo JY, Park CM, Lee NK, Lee SM, Lee HJ, Goo JM. Percutaneous transthoracic needle biopsy of small (≤1 cm) lung nodules under C-arm cone-beam CT virtual navigation guidance. Eur Radiol 2013;23:712-719. PMID: 22976917.

13. Hwang HS, Chung MJ, Lee JW, Shin SW, Lee KS. C-arm conebeam CT-guided percutaneous transthoracic lung biopsy: usefulness in evaluation of small pulmonary nodules. AJR Am J Roentgenol 2010;195:W400-W407. PMID: 21098171.

14. Larke FJ, Kruger RL, Cagnon CH, Flynn MJ, McNitt-Gray MM, Wu X, et al. Estimated radiation dose associated with low-dose chest CT of average-size participants in the National Lung Screening Trial. AJR Am J Roentgenol 2011;197:1165-1169. PMID: 22021510.

15. Hiraki T, Mimura H, Gobara H, Iguchi T, Fujiwara H, Sakurai J, et al. CT fluoroscopy-guided biopsy of 1,000 pulmonary lesions performed with 20-gauge coaxial cutting needles: diagnostic yield and risk factors for diagnostic failure. Chest 2009;136:1612-1617. PMID: 19429718.

16. Chami HA, Faraj W, Yehia ZA, Badour SA, Sawan P, Rebeiz K, et al. Predictors of pneumothorax after CT-guided transthoracic needle lung biopsy: the role of quantitative CT. Clin Radiol 2015;70:1382-1387. PMID: 26392317.

17. Boskovic T, Stanic J, Pena-Karan S, Zarogoulidis P, Drevelegas K, Katsikogiannis N, et al. Pneumothorax after transthoracic needle biopsy of lung lesions under CT guidance. J Thorac Dis 2014;6(Suppl 1):S99-S107. PMID: 24672704.

18. van Haren-Willems J, Heijdra Y. Increasing evidence for gender differences in chronic obstructive pulmonary disease. Womens Health (Lond) 2010;6:595-600. PMID: 20597622.

19. Yeow KM, Tsay PK, Cheung YC, Lui KW, Pan KT, Chou AS. Factors affecting diagnostic accuracy of CT-guided coaxial cutting needle lung biopsy: retrospective analysis of 631 procedures. J Vasc Interv Radiol 2003;14:581-588. PMID: 12761311.

20. Ko JP, Shepard JO, Drucker EA, Aquino SL, Sharma A, Sabloff B, et al. Factors influencing pneumothorax rate at lung biopsy: are dwell time and angle of pleural puncture contributing factors? Radiology 2001;218:491-496. PMID: 11161167.

21. Khan MF, Straub R, Moghaddam SR, Maataoui A, Gurung J, Wagner TO, et al. Variables affecting the risk of pneumothorax and intrapulmonal hemorrhage in CT-guided transthoracic biopsy. Eur Radiol 2008;18:1356-1363. PMID: 18351356.

22. Rotolo N, Floridi C, Imperatori A, Fontana F, Ierardi AM, Mangini M, et al. Comparison of cone-beam CT-guided and CT fluoroscopy-guided transthoracic needle biopsy of lung nodules. Eur Radiol 2016;26:381-389. PMID: 26045345.

23. Adiga S, Athreya S. Safety, efficacy, and feasibility of an ultra-low dose radiation protocol for CT-guided percutaneous needle biopsy of pulmonary lesions: initial experience. Clin Radiol 2014;69:709-714. PMID: 24709093.

24. Lechuga L, Weidlich GA. Cone beam CT vs. fan beam CT: a comparison of image quality and dose delivered between two differing CT imaging modalities. Cureus 2016;8:e778. PMID: 27752404.

25. Schegerer AA, Lechel U, Ritter M, Weisser G, Fink C, Brix G. Dose and image quality of cone-beam computed tomography as compared with conventional multislice computed tomography in abdominal imaging. Invest Radiol 2014;49:675-684. PMID: 24853071.

26. Ravenel JG, Scalzetti EM, Huda W, Garrisi W. Radiation exposure and image quality in chest CT examinations. AJR Am J Roentgenol 2001;177:279-284. PMID: 11461845.

27. Hirota S, Nakao N, Yamamoto S, Kobayashi K, Maeda H, Ishikura R, et al. Cone-beam CT with flat-panel-detector digital angiography system: early experience in abdominal interventional procedures. Cardiovasc Intervent Radiol 2006;29:1034-1038. PMID: 16988877.

Figure 1

Laser level (HG-909A; X-CLOVE) and a wheel bracket. (A) Laser level, adhered to a wheel bracket. (B, D) Overhead and side view of laser level. (C) Wheel part of a bracket.

Figure 2

(A) The laser level, adhered to a wheel bracket, mounted on a stainless steel frame and positioned on the opposite side of the computed tomography (CT) gantry. Horizontal movement is possible (blue arrows). (B) Both vertical laser beam lines, which came from the laser level and CT gantry, had been aligned, such that they looked like a line (red arrows). (C) The second laser level was placed on the side of the patient opposite to the operator, perpendicular to the other laser. (D) In the case of an oblique approach, a digital level (DWL-80E, Sincon) was used to tilt the laser level. The digital level was 29.9° (red round arrows).

Figure 3

Adjustment of the laser lines. (A, B) The laser line originating from the head end was located at the entry point on the skin and ran along the coaxial needle. (C, D) The intersection of the two laser lines originating from the head end and the side opposite to the operator were matched at the entry point on the skin and ran long the coaxial needle.

Figure 4

A 76-year-old woman who was diagnosed with non-small cell lung cancer (adenocarcinoma) by percutaneous transthoracic needle biopsy. (A) Axial view. (B) Sagittal view.

Table 1

Baseline characteristics and procedure records (n=244)

Values are presented as means±SD or numbers (%) unless otherwise indicated.

^*Missing data were excluded from the analysis.

FEV₁: forced expiratory volume in 1 second; FVC: forced vital capacity; CT: computed tomography.

Variable	Value
Patient
Age, yr	66.5±11.3
Sex
Male	158 (64.8)
Female	86 (35.2)
Pulmonary function test (n=198)*, %
FEV₁	100.8±24.6
FVC	99.8±19.6
FEV₁/FVC	70.3±13.4
Target lesion
Lesion location
Upper and middle lobes	143 (58.6)
Lower lobes	101 (41.4)
CT findings
Solid	218 (89.3)
Subsolid	14 (5.7)
Ground glass appearance	12 (4.9)
Longest diameter of the target lesion, mm	33.8±20.1
Target lesion size, mm
≤10	17 (7.0)
11-30	118 (48.4)
31-50	63 (25.8)
51-70	35 (14.3)
>70	11 (4.5)
Procedure
Patient position
Supine	79 (32.4)
Prone	159 (65.2)
Decubitus	6 (2.4)
Needle diameter (gauge)
16	58 (23.8)
18	136 (55.7)
20	50 (20.5)
Distance from skin to target lesion, mm	51.8±21.5
Distance from skin to pleura, mm	31.9±10.1
Distance from pleura to target lesion, mm	19.8±17.4
Total procedure time, min	8.8±2.9
Needle dwelling time, min	2.2±1.3
No. of tissue samplings	2.2±1.2
Radiation dose, mGy	60.3±24.1
Effective radiation dose, mSv	1.0±0.4

Table 2

Pathological results and final diagnoses of malignancies (n=161)

^*Nine malignant lesions had been diagnosed as benign lesions by PTNB.

NSCLC: non-small cell lung cancer; NOS: not otherwise specified.

	Pathologic results (n=152)^*	Final diagnoses (n=161)
Lung cancers
Adenocarcinoma	83	85
Squamous carcinoma	42	48
NSCLC, NOS	5	5
Small cell carcinoma	8	9
Large cell carcinoma	4	4
Metastases
Breast cancer	2	2
Colorectal cancer	2	2
Melanoma	2	2
Renal cell carcinoma	1	1
Stomach cancer	1	1
Cervical cancer	2	2

Table 3

Risk factors for diagnostic failure (n=238)

Values are presented as means±SD or numbers (%) unless otherwise indicated.

^*Missing data were excluded from the analysis.

FEV₁: forced expiratory volume in 1 second; FVC: forced vital capacity; CT: computed tomography.

Variable	Diagnostic success (n=229)	Diagnostic failure (n=9)	p-value
Patient
Age, yr	66.8±11.1	66.7±9.4	0.496
Sex			0.029
Male	146 (94.2)	9 (5.8)
Female	83 (100)	0 (0)
Pulmonary function test (n=198)^*, %
FEV₁	100.9±23.8	98.0±35.4	0.584
FVC	99.7±20.0	100.8±11.5	0.922
FEV₁/FVC	70.5±13.1	65.9±16.3	0.179
Target lesion
Final diagnosis			0.033
Benign	77 (100)	0 (0)
Malignancy	152 (94.4)	9 (5.6)
Lesion location			0.035
Upper and middle lobes	138 (98.6)	2 (1.4)
Lower lobes	91 (92.9)	7 (7.1)
CT findings			0.604
Solid	205 (95.8)	9 (4.2)
Subsolid and ground glass appearance	24 (100)	0 (0)
Necrosis			0.457
Yes	97 (94.4)	4 (5.6)
No	162 (97.0)	5 (3.0)
Cavity			0.571
Yes	20 (95.2)	1 (4.8)
No	209 (96.3)	8 (3.7)
Size, mm			0.274
≤10	15 (93.8)	1 (6.3)
11-30	109 (95.6)	5 (4.4)
31-50	63 (100)	0 (0)
>50	42 (93.3)	3 (6.7)
Distance from skin to target lesion, mm	52.6±20.6	33.4±9.5	0.003
Distance from skin to pleura	32.2±10.3	27.2±6.6	0.149
Distance from pleura to target lesion	20.4±17.5	6.2±5.8	0.006
Procedure
Patient position			0.696
Supine	74 (97.4)	2 (2.6)
Prone	149 (95.5)	7 (4.5)
Decubitus	6 (100)	0 (0)
Needle diameter (gauge)			0.660
16	55 (98.2)	1 (1.8)
18	126 (95.5)	6 (4.5)
20	48 (96.0)	2 (4.0)
Procedure time, min
Total procedure time	8.7±2.6	7.2±2.4	0.152
Needle dwelling time	2.2±0.9	2.7±2.3	0.803
Tissue acquisition
No. of tissue samplings	2.2±1.2	2.2±1.1	0.823
Length of obtained tissue, mm	32.5±15.4	31.7±13.7	0.990
Complications
Overall			0.465
Yes	70 (94.6)	4 (5.4)
No	159 (97.0)	5 (3.0)
Pneumothorax			0.114
Yes	49 (92.5)	4 (7.5)
No	180 (97.3)	5 (2.7)
Hemoptysis			1.000
Yes	22 (100)	0 (0)
No	207 (95.8)	9 (4.2)