Skip to main content

Advertisement

Log in

Periprocedural Management in Transthoracic Needle Biopsy: Review of the Current Evidence

  • Chest Imaging (T Henry, Section Editor)
  • Published:
Current Radiology Reports Aims and scope Submit manuscript

Abstract

Purpose of Review

Transthoracic needle biopsy (TTNB) is a common diagnostic tool with expanding clinical indications. While most literature on this topic has focused on complications and techniques, this review will examine the evidence for periprocedural care specific to lung biopsy.

Recent Findings

Review of the literature reveals great heterogeneity in clinical practice regarding periprocedural management of TTNB, for example, in terms of post-procedural monitoring as well as strategies for dealing with potential complications of TTNB. This is on the basis of a relative paucity of systematic clinical studies to guide management specific to the procedure.

Summary

Further studies focused on periprocedural management in TTNB are needed to establish evidence-based guidelines that address the unique clinical aspects and complications of this procedure.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

Similar content being viewed by others

References

Recently published papers of particular interest have been highlighted as: • Of importance

  1. Nordenström B. A new technique for transthoracic biopsy of lung changes. Br J Radiol. 1965;38(451):550–3. https://doi.org/10.1259/0007-1285-38-451-550.

    Google Scholar 

  2. Lorenz JM. Updates in percutaneous lung biopsy: new indications, techniques and controversies. Semin Intervent Radiol. 2012;29(4):319–24. https://doi.org/10.1055/s-0032-1330067.

    PubMed  PubMed Central  Google Scholar 

  3. DiBardino DM, Yarmus LB, Semaan RW. Transthoracic needle biopsy of the lung. J Thorac Dis. 2015;7(Suppl 4):S304–16. https://doi.org/10.3978/j.issn.2072-1439.2015.12.16.

    PubMed  PubMed Central  Google Scholar 

  4. Klein JS, Zarka MA. Transthoracic needle biopsy. Radiol Clin N Am. 2000;38(2):235–66, vii.

  5. Birchard KR. Transthoracic needle biopsy. Semin Intervent Radiol. 2011;28(1):87–97. https://doi.org/10.1055/s-0031-1273943.

    PubMed  PubMed Central  Google Scholar 

  6. Winokur RS, Pua BB, Sullivan BW, Madoff DC. Percutaneous lung biopsy: technique, efficacy, and complications. Semin Intervent Radiol. 2013;30(2):121–7. https://doi.org/10.1055/s-0033-1342952.

    PubMed  PubMed Central  Google Scholar 

  7. 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(6):e0131373. https://doi.org/10.1371/journal.pone.0131373.

    PubMed  PubMed Central  Google Scholar 

  8. • Chang YY, Chen CK, Yeh YC, Wu MH. Diagnostic feasibility and safety of CT-guided core biopsy for lung nodules less than or equal to 8 mm: a single-institution experience. Eur Radiol. 2017. https://doi.org/10.1007/s00330-017-5027-1. This study specifically examines the biopsy of nodules smaller than 8 mm while most previous studies have used a larger upper limit of 10 mm.

  9. • Tam AL, Lim HJ, Wistuba, II, Tamrazi A, Kuo MD, Ziv E, et al. Image-guided biopsy in the era of personalized cancer care: proceedings from the society of interventional radiology research consensus panel. J Vasc Interv Radiol. 2016;27(1):8–19. https://doi.org/10.1016/j.jvir.2015.10.019. This article is an excellent resource for updates for the role of image-guided biopsy in individualized treatments.

  10. Haas BM, Clayton JD, Elicker BM, Ordovas KG, Naeger DM. CT-guided percutaneous lung biopsies in patients with suspicion for infection may yield clinically useful information. AJR Am J Roentgenol. 2017;208(2):459–63. https://doi.org/10.2214/AJR.16.16255.

    PubMed  Google Scholar 

  11. Haas BM, Elicker BM, Nguyen J, Ordovas KG, Jones KD, Henry TS, et al. Nondiagnostic computed tomography-guided percutaneous lung biopsies are more likely when infection is suspected. J Thorac Imaging. 2016;31(3):151–5. https://doi.org/10.1097/RTI.0000000000000207.

    PubMed  Google Scholar 

  12. Meyer CA. “Transthoracic needle aspiration biopsy of benign and malignant lung lesions”—a commentary. AJR Am J Roentgenol. 2007;188(4):891–3. https://doi.org/10.2214/AJR.06.0986.

    PubMed  Google Scholar 

  13. • Lass-Florl C, Aigner M, Nachbaur D, Eschertzhuber S, Bucher B, Geltner C, et al. Diagnosing filamentous fungal infections in immunocompromised patients applying computed tomography-guided percutaneous lung biopsies: a 12-year experience. Infection. 2017. https://doi.org/10.1007/s15010-017-1072-6. This study establishes a protocol that can be used to improve the yield in percutaneous biopsy for the diagnosis of fungal infections, thought to previously be less useful.

  14. Lass-Florl C, Resch G, Nachbaur D, Mayr A, Gastl G, Auberger J, et al. The value of computed tomography-guided percutaneous lung biopsy for diagnosis of invasive fungal infection in immunocompromised patients. Clin Infect Dis. 2007;45(7):e101–4. https://doi.org/10.1086/521245.

    PubMed  Google Scholar 

  15. Klein JS, Salomon G, Stewart EA. Transthoracic needle biopsy with a coaxially placed 20-gauge automated cutting needle: results in 122 patients. Radiology. 1996;198(3):715–20. https://doi.org/10.1148/radiology.198.3.8628859.

    CAS  PubMed  Google Scholar 

  16. Boiselle PM, Shepard JA, Mark EJ, Szyfelbein WM, Fan CM, Slanetz PJ, et al. Routine addition of an automated biopsy device to fine-needle aspiration of the lung: a prospective assessment. AJR Am J Roentgenol. 1997;169(3):661–6.

    Article  CAS  PubMed  Google Scholar 

  17. • Heerink WJ, de Bock GH, de Jonge GJ, Groen HJ, Vliegenthart R, Oudkerk M. Complication rates of CT-guided transthoracic lung biopsy: meta-analysis. Eur Radiol. 2017;27(1):138–48. https://doi.org/10.1007/s00330-016-4357-8. This is the most comprehensive and recent meta-analysis regarding the complications of transthoracic lung biopsy.

  18. Mills M, Choi J, El-Haddad G, Sweeney J, Biebel B, Robinson L, et al. Retrospective analysis of technical success rate and procedure-related complications of 867 percutaneous CT-guided needle biopsies of lung lesions. Clin Radiol. 2017. https://doi.org/10.1016/j.crad.2017.07.023.

    PubMed  Google Scholar 

  19. Sangha BS, Hague CJ, Jessup J, O’Connor R, Mayo JR. Transthoracic computed tomography-guided lung nodule biopsy: comparison of core needle and fine needle aspiration techniques. Can Assoc Radiol J. 2016;67(3):284–9. https://doi.org/10.1016/j.carj.2015.10.005.

    PubMed  Google Scholar 

  20. Clayton JD, Elicker BM, Ordovas KG, Kohi MP, Nguyen J, Naeger DM. Nonclotted blood patch technique reduces pneumothorax and chest tube placement rates after percutaneous lung biopsies. J Thorac Imaging. 2016;31(4):243–6. https://doi.org/10.1097/RTI.0000000000000215.

    PubMed  Google Scholar 

  21. Ko JM, Ahn MI, Han DH. CT-guided core biopsy of the lung: comments on the technical details. AJR Am J Roentgenol. 2011;196(3):W350; author reply W1. https://doi.org/10.2214/ajr.10.5328.

  22. Aviram G, Schwartz DS, Meirsdorf S, Rosen G, Greif J, Graif M. Transthoracic needle biopsy of lung masses: a survey of techniques. Clin Radiol. 2005;60(3):370–4. https://doi.org/10.1016/j.crad.2004.09.006.

    CAS  PubMed  Google Scholar 

  23. Patel IJ, Davidson JC, Nikolic B, Salazar GM, Schwartzberg MS, Walker TG, et al. Consensus guidelines for periprocedural management of coagulation status and hemostasis risk in percutaneous image-guided interventions. J Vasc Interv Radiol. 2012;23(6):727–36. https://doi.org/10.1016/j.jvir.2012.02.012.

    PubMed  Google Scholar 

  24. Cronin CG, Sharma A, Digumarthy SR, Gilman MD, McLoud T, Muse VV, et al. Percutaneous lung biopsy after pneumonectomy: factors for improving success in the care of patients at high risk. AJR Am J Roentgenol. 2011;196(4):929–34. https://doi.org/10.2214/AJR.10.4920.

    PubMed  Google Scholar 

  25. Manhire A, Charig M, Clelland C, Gleeson F, Miller R, Moss H, et al. Guidelines for radiologically guided lung biopsy. Thorax. 2003;58(11):920–36.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  26. Perlmutt LM, Johnston WW, Dunnick NR. Percutaneous transthoracic needle aspiration: a review. AJR Am J Roentgenol. 1989;152(3):451–5. https://doi.org/10.2214/ajr.152.3.451.

    CAS  PubMed  Google Scholar 

  27. Digumarthy SR, Kovacina B, Otrakji A, Lanuti M, Shepard JA, Sharma A. Percutaneous CT guided lung biopsy in patients with pulmonary hypertension: assessment of complications. Eur J Radiol. 2016;85(2):466–71. https://doi.org/10.1016/j.ejrad.2015.12.007.

    PubMed  Google Scholar 

  28. Veltri A, Bargellini I, Giorgi L, Almeida PAMS, Akhan O. CIRSE guidelines on percutaneous needle biopsy (PNB). Cardiovasc Intervent Radiol. 2017;40(10):1501–13.

    Article  PubMed  Google Scholar 

  29. Patel IJ, Davidson JC, Nikolic B, Salazar GM, Schwartzberg MS, Walker TG, et al. Addendum of newer anticoagulants to the SIR consensus guideline. J Vasc Interv Radiol. 2013;24(5):641–5. https://doi.org/10.1016/j.jvir.2012.12.007.

    PubMed  Google Scholar 

  30. Jaffe TA, Raiff D, Ho LM, Kim CY. Management of anticoagulant and antiplatelet medications in adults undergoing percutaneous interventions. AJR Am J Roentgenol. 2015;205(2):421–8. https://doi.org/10.2214/AJR.14.13342.

    PubMed  Google Scholar 

  31. Kirley K, Qato DM, Kornfield R, Stafford RS, Alexander GC. National trends in oral anticoagulant use in the United States, 2007 to 2011. Circ Cardiovasc Qual Outcomes. 2012;5(5):615–21. https://doi.org/10.1161/CIRCOUTCOMES.112.967299.

    PubMed  PubMed Central  Google Scholar 

  32. Hirsh J, Dalen J, Anderson DR, Poller L, Bussey H, Ansell J, et al. Oral anticoagulants: mechanism of action, clinical effectiveness, and optimal therapeutic range. Chest. 2001;119(1 Suppl):8S–21S.

    Article  CAS  PubMed  Google Scholar 

  33. McAvoy TJ. The biologic half-life of heparin. Clin Pharmacol Ther. 1979;25(3):372–9.

    Article  CAS  PubMed  Google Scholar 

  34. Baron TH, Kamath PS, McBane RD. Management of antithrombotic therapy in patients undergoing invasive procedures. N Engl J Med. 2013;368(22):2113–24. https://doi.org/10.1056/NEJMra1206531.

    CAS  PubMed  Google Scholar 

  35. Bou-Assaly W, Pernicano P, Hoeffner E. Systemic air embolism after transthoracic lung biopsy: a case report and review of literature. World J Radiol. 2010;2(5):193–6. https://doi.org/10.4329/wjr.v2.i5.193.

    PubMed  PubMed Central  Google Scholar 

  36. Tsai IC, Tsai WL, Chen MC, Chang GC, Tzeng WS, Chan SW, et al. CT-guided core biopsy of lung lesions: a primer. AJR Am J Roentgenol. 2009;193(5):1228–35. https://doi.org/10.2214/AJR.08.2113.

    PubMed  Google Scholar 

  37. Glodny B, Schonherr E, Freund MC, Haslauer M, Petersen J, Loizides A, et al. Measures to prevent air embolism in transthoracic biopsy of the lung. AJR Am J Roentgenol. 2017;208(5):W184–91. https://doi.org/10.2214/AJR.16.16048.

    PubMed  Google Scholar 

  38. ACR-SIR-SPR Practice Parameter on Informed Consent for Image-guided Procedures. American College of Radiogy Website. https://www.acr.org/~/media/1A03224CA4894854800C516012B6DB5A.pdf. (2016). Accessed November 25 2017.

  39. Lee C, Guichet PL, Abtin F. Percutaneous lung biopsy in the molecular profiling era: a survey of current practices. J Thorac Imaging. 2017;32(1):63–7. https://doi.org/10.1097/RTI.0000000000000237.

    PubMed  Google Scholar 

  40. Sun C, Bian J, Lai S, Li X. Systemic air embolism as a complication of CT-guided percutaneous core needle lung biopsy: a case report and review of the literature. Exp Ther Med. 2015;10(3):1157–60. https://doi.org/10.3892/etm.2015.2643.

    PubMed  PubMed Central  Google Scholar 

  41. Freund MC, Petersen J, Goder KC, Bunse T, Wiedermann F, Glodny B. Systemic air embolism during percutaneous core needle biopsy of the lung: frequency and risk factors. BMC Pulm Med. 2012;12:2. https://doi.org/10.1186/1471-2466-12-2.

    PubMed  PubMed Central  Google Scholar 

  42. Richardson CM, Pointon KS, Manhire AR, Macfarlane JT. Percutaneous lung biopsies: a survey of UK practice based on 5444 biopsies. Br J Radiol. 2002;75(897):731–5. https://doi.org/10.1259/bjr.75.897.750731.

    CAS  PubMed  Google Scholar 

  43. Protopapas Z, White CS, Miller BH, Miller DL, Westcott JL. Transthoracic needle biopsy practices: results of a nationwide survey. Radiology. 1996;201:270–1.

    Google Scholar 

  44. Fontaine-Delaruelle C, Souquet PJ, Gamondes D, Pradat E, De Leusse A, Ferretti GR, et al. Negative predictive value of transthoracic core-needle biopsy: a multicenter study. Chest. 2015;148(2):472–80. https://doi.org/10.1378/chest.14-1907.

    PubMed  Google Scholar 

  45. Li H, Boiselle PM, Shepard JO, Trotman-Dickenson B, McLoud TC. Diagnostic accuracy and safety of CT-guided percutaneous needle aspiration biopsy of the lung: comparison of small and large pulmonary nodules. AJR Am J Roentgenol. 1996;167(1):105–9. https://doi.org/10.2214/ajr.167.1.8659351.

    CAS  PubMed  Google Scholar 

  46. Wallace MJ, Krishnamurthy S, Broemeling LD, Gupta S, Ahrar K, Morello FA Jr, et al. CT-guided percutaneous fine-needle aspiration biopsy of small (< or = 1-cm) pulmonary lesions. Radiology. 2002;225(3):823–8. https://doi.org/10.1148/radiol.2253011465.

    PubMed  Google Scholar 

  47. Tavare AN, Creer DD, Khan S, Vancheeswaran R, Hare SS. Ambulatory percutaneous lung biopsy with early discharge and Heimlich valve management of iatrogenic pneumothorax: more for less. Thorax. 2016;71(2):190–2. https://doi.org/10.1136/thoraxjnl-2015-207352.

    CAS  PubMed  Google Scholar 

  48. Gupta S, Hicks ME, Wallace MJ, Ahrar K, Madoff DC, Murthy R. Outpatient management of postbiopsy pneumothorax with small-caliber chest tubes: factors affecting the need for prolonged drainage and additional interventions. Cardiovasc Intervent Radiol. 2008;31(2):342–8. https://doi.org/10.1007/s00270-007-9250-z.

    PubMed  Google Scholar 

  49. Yamagami T, Nakamura T, Iida S, Kato T, Nishimura T. Management of pneumothorax after percutaneous CT-guided lung biopsy. Chest. 2002;121(4):1159–64.

    Article  PubMed  Google Scholar 

  50. Dennie CJ, Matzinger FR, Marriner JR, Maziak DE. Transthoracic needle biopsy of the lung: results of early discharge in 506 outpatients. Radiology. 2001;219(1):247–51. https://doi.org/10.1148/radiology.219.1.r01ap11247.

    CAS  PubMed  Google Scholar 

  51. Perlmutt LM, Braun SD, Newman GE, Oke EJ, Dunnick NR. Timing of chest film follow-up after transthoracic needle aspiration. AJR Am J Roentgenol. 1986;146(5):1049–50. https://doi.org/10.2214/ajr.146.5.1049.

    CAS  PubMed  Google Scholar 

  52. Yamagami T, Kato T, Hirota T, Yoshimatsu R, Matsumoto T, Nishimura T. Usefulness and limitation of manual aspiration immediately after pneumothorax complicating interventional radiological procedures with the transthoracic approach. Cardiovasc Intervent Radiol. 2006;29(6):1027–33. https://doi.org/10.1007/s00270-005-0368-6.

    PubMed  Google Scholar 

  53. Yamagami T, Terayama K, Yoshimatsu R, Matsumoto T, Miura H, Nishimura T. Role of manual aspiration in treating pneumothorax after computed tomography-guided lung biopsy. Acta Radiol. 2009;50(10):1126–33. https://doi.org/10.3109/02841850903232707.

    CAS  PubMed  Google Scholar 

  54. Shantaveerappa HN, Mathai MG, Byrd RP Jr, Karnad AB, Mehta JB, Roy TM. Intervention in patients with pneumothorax immediately following CT-guided fine needle aspiration of pulmonary nodules. Med Sci Monit. 2002;8(6):CR401–4.

    PubMed  Google Scholar 

  55. Yamagami T, Kato T, Iida S, Hirota T, Yoshimatsu R, Nishimura T. Efficacy of manual aspiration immediately after complicated pneumothorax in CT-guided lung biopsy. J Vasc Interv Radiol. 2005;16(4):477–83. https://doi.org/10.1097/01.RVI.0000150032.12842.9E.

    PubMed  Google Scholar 

  56. Yankelevitz DF, Davis SD, Henschke CI. Aspiration of a large pneumothorax resulting from transthoracic needle biopsy. Radiology. 1996;200(3):695–7. https://doi.org/10.1148/radiology.200.3.8756917.

    CAS  PubMed  Google Scholar 

  57. Haramati LB, Aviram G. What constitutes effective management of pneumothorax after CT-guided needle biopsy of the lung? Chest. 2002;121(4):1013–5.

    Article  PubMed  Google Scholar 

  58. Noh TJ, Lee CH, Kang YA, Kwon SY, Yoon HI, Kim TJ, et al. Chest computed tomography (CT) immediately after CT-guided transthoracic needle aspiration biopsy as a predictor of overt pneumothorax. Korean J Intern Med. 2009;24(4):343–9. https://doi.org/10.3904/kjim.2009.24.4.343.

    PubMed  PubMed Central  Google Scholar 

  59. Choi CM, Um SW, Yoo CG, Kim YW, Han SK, Shim YS, et al. Incidence and risk factors of delayed pneumothorax after transthoracic needle biopsy of the lung. Chest. 2004;126(5):1516–21. https://doi.org/10.1378/chest.126.5.1516.

    PubMed  Google Scholar 

  60. Traill ZC, Gleeson FV. Delayed pneumothorax after CT-guided percutaneous fine needle aspiration lung biopsy. Thorax. 1997;52(6):581–2 ; discussion 75–76.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  61. Veltri A, Bargellini I, Giorgi L, Almeida P, Akhan O. CIRSE guidelines on percutaneous needle biopsy (PNB). Cardiovasc Intervent Radiol. 2017. https://doi.org/10.1007/s00270-017-1658-5.

    Google Scholar 

  62. Tai R, Dunne RM, Trotman-Dickenson B, Jacobson FL, Madan R, Kumamaru KK, et al. Frequency and severity of pulmonary hemorrhage in patients undergoing percutaneous CT-guided transthoracic lung biopsy: single-institution experience of 1175 cases. Radiology. 2016;279(1):287–96. https://doi.org/10.1148/radiol.2015150381.

    PubMed  Google Scholar 

  63. Balsara ZN, Burks DD. Hyperbaric oxygen therapy for arterial air embolism. AJR Am J Roentgenol. 2007;188(1):W98 ; author reply W9.

    Article  PubMed  Google Scholar 

  64. Kok HK, Leong S, Salati U, Torreggiani WC, Govender P. Left atrial and systemic air embolism after lung biopsy: importance of treatment positioning. J Vasc Interv Radiol. 2013;24(10):1587–8. https://doi.org/10.1016/j.jvir.2013.07.007.

    PubMed  Google Scholar 

  65. McCarthy CJ, Behravesh S, Naidu SG, Oklu R. Air embolism: practical tips for prevention and treatment. J Clin Med. 2016;5(11):93.

    Article  PubMed Central  Google Scholar 

  66. Rott G, Boecker F. Influenceable and avoidable risk factors for systemic air embolism due to percutaneous CT-guided lung biopsy: patient positioning and coaxial biopsy technique-case report, systematic literature review, and a technical note. Radiol Res Pract. 2014;2014:349062. https://doi.org/10.1155/2014/349062.

    PubMed  PubMed Central  Google Scholar 

  67. Mizutani E, Nakahara K, Miyanaga S, Yoshiya T. Hyperbaric oxygen therapy for air embolism complicating computed tomography (CT)-guided needle marking of the lung. Kyobu Geka. 2012;65(10):899–902.

    PubMed  Google Scholar 

  68. Tomabechi M, Kato K, Sone M, Ehara S, Sekimura K, Kizawa T, et al. Cerebral air embolism treated with hyperbaric oxygen therapy following percutaneous transthoracic computed tomography-guided needle biopsy of the lung. Radiat Med. 2008;26(6):379–83. https://doi.org/10.1007/s11604-008-0242-y.

    PubMed  Google Scholar 

  69. Lattin G Jr, O’Brien W Sr, McCrary B, Kearney P, Gover D. Massive systemic air embolism treated with hyperbaric oxygen therapy following CT-guided transthoracic needle biopsy of a pulmonary nodule. J Vasc Interv Radiol. 2006;17(8):1355–8. https://doi.org/10.1097/01.RVI.0000231949.35479.89.

    PubMed  Google Scholar 

  70. Ashizawa K, Watanabe H, Morooka H, Hayashi K. Hyperbaric oxygen therapy for air embolism complicating CT-guided needle biopsy of the lung. AJR Am J Roentgenol. 2004;182(6):1606–7. https://doi.org/10.2214/ajr.182.6.1821606.

    PubMed  Google Scholar 

  71. Ohashi S, Endoh H, Honda T, Komura N, Satoh K. Cerebral air embolism complicating percutaneous thin-needle biopsy of the lung: complete neurological recovery after hyperbaric oxygen therapy. J Anesth. 2001;15(4):233–6. https://doi.org/10.1007/s005400170008.

    CAS  PubMed  Google Scholar 

  72. Tam A, Singh P, Ensor JE, Carter K, Kim ES, Hicks ME, et al. Air travel after biopsy-related pneumothorax: is it safe to fly? J Vasc Interv Radiol JVIR. 2011;22(5):595–602.e1.

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to David M. Naeger.

Ethics declarations

Conflict of interest

Eric R. Flagg, Brett M. Elicker, Kim G. Kallianos, and David M. Naeger each declare no potential conflicts of interest. Travis S. Henry is a section editor for Current Radiology Reports. Karen G. Ordovas is a section editor for Current Radiology Reports.

Human and Animal Rights and Informed Consent

This article does not contain any studies with human or animal subjects performed by any of the authors.

Additional information

This article is part of the Topical collection on Chest Imaging.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Flagg, E.R., Henry, T.S., Elicker, B.M. et al. Periprocedural Management in Transthoracic Needle Biopsy: Review of the Current Evidence. Curr Radiol Rep 6, 13 (2018). https://doi.org/10.1007/s40134-018-0274-8

Download citation

  • Published:

  • DOI: https://doi.org/10.1007/s40134-018-0274-8

Keywords

Navigation