SpringerLink
Log in

Validating the safety of low-dose CTPA in pregnancy: results from the OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) Study

  • Chest
  • Published:
European Radiology Aims and scope Submit manuscript

Abstract

Background

Pulmonary embolism (PE) is a leading cause of pregnancy-related mortality. CT pulmonary angiogram (CTPA) is the first-line advanced imaging modality for suspected PE in pregnancy at institutes offering low-dose techniques; however, a protocol balancing safety with low dose remains undefined. The wide range of CTPA doses reported in pregnancy suggests a lack of confidence in implementing low-dose techniques in this group.

Purpose

To define and validate the safety, radiation dose and image quality of a low-dose CTPA protocol optimised for pregnancy.

Materials and methods

The OPTICA study is a prospective observational study. Pregnant study participants with suspected PE underwent the same CTPA protocol between May 2018 and February 2022. The primary outcome, CTPA safety, was judged by the reference standard; the 3-month incidence of venous thromboembolism (VTE) in study participants with a negative index CTPA. Secondary outcomes defined radiation dose and image quality. Absorbed breast, maternal effective and fetal doses were estimated by Monte-Carlo simulation on gestation-matched phantoms. Image quality was assessed by signal-to-noise and contrast-to-noise ratios and a Likert score for pulmonary arterial enhancement.

Results

A total of 116 CTPAs were performed in 113 pregnant women of which 16 CTPAs were excluded. PE was diagnosed on 1 CTPA and out-ruled in 99. The incidence of recurrent symptomatic VTE was 0.0% (one-sided 95% CI, 2.66%) at follow-up. The mean absorbed breast dose was 2.9 ± 2.1mGy, uterine/fetal dose was 0.1 ± 0.2mGy and maternal effective dose was 1.4 ± 0.9mSv. Signal-to-noise ratio (SNR) was 11.9 ± 3.7. Contrast-to-noise ratio (CNR) was 10.4 ± 3.5.

Conclusion

The OPTICA CTPA protocol safely excluded PE in pregnant women across all trimesters, with low fetal and maternal radiation.

Clinical relevance

OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) is the first prospective study to define the achievable radiation dose, image-quality and safety of a low-dose CT pulmonary angiogram protocol optimised for pregnancy (NCT04179487). It provides the current benchmark for safe and achievable CT pulmonary angiogram doses in the pregnant population.

Key Points

• Despite the increased use of CT pulmonary angiogram in pregnancy, an optimised low-dose protocol has not been defined and reported doses in pregnancy continue to vary widely.

• The OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) study prospectively defines the achievable dose, image quality and safety of a low-dose CT pulmonary angiogram protocol using widely available technology.

• OPTICA provides a benchmark for safe and achievable CT pulmonary angiogram doses in the pregnant population.

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

Access this article

Log in via an institution

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price includes VAT (United Kingdom)

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2

Similar content being viewed by others

Abbreviations

AEC:

Automatic exposure control

ATPM:

Automatic tube potential modulation

CIAC:

Central independent adjudication committee

CNR:

Contrast-to-noise ratio

CTDIvol:

Volume CT dose index

DLP:

Dose length product

ICC:

Intra-class correlation coefficient

IQR:

Interquartile range

PE:

Pulmonary embolism

SNR:

Signal-to-noise ratio

VTE:

Venous thromboembolism

References

  1. Righini M, Robert-Ebadi HEA, Sanchez O et al (2018) Diagnosis of pulmonary embolism during pregnancy. a multicenter prospective management outcome study. Ann Intern Med 169:766–773

    Article  PubMed  Google Scholar 

  2. Van der Pol LM, Tromeur C, Bistervels IM et al (2019) Pregnancy-adapted YEARS algorithm for diagnosis of suspected pulmonary embolism. N Engl J Med 80:1139–1149

    Google Scholar 

  3. van Mens TE, Scheres LJJ, de Jong PG, Leeflang MMG, Nijkeuter M, Middeldorp S (2017) Imaging for the exclusion of pulmonary embolism in pregnancy. Cochrane Database Syst Rev CD011053

  4. Tromeur C, Van der Pol LM, Le Roux PY et al (2019) Computed tomography pulmonary angiography versus ventilation-perfusion lung scanning for diagnosing pulmonary embolism during pregnancy: a systematic review and meta-analysis. Haematologica 104:176–188

    Article  PubMed  PubMed Central  Google Scholar 

  5. Remy-Jardin M, Pistolesi M, Goodman LR et al (2007) Management of suspected acute pulmonary embolism in the era of CT angiography: a statement from the Fleischner society. Radiology 245:315–329

    Article  PubMed  Google Scholar 

  6. Hurwitz LM, Yoshizumi TT, Reiman RE et al (2006) Radiation dose to the female breast from 16-MDCT body protocols. AJR Am J Roentgenol 186:1718–1722

    Article  PubMed  Google Scholar 

  7. Parker MS, Hui FK, Camacho MA, Chung JK, Broga DW, Sethi NN (2005) Female breast radiation exposure during CT pulmonary angiography. AJR Am J Roentgenol 185:1228–1233

    Article  PubMed  Google Scholar 

  8. Konstantinides SV, Meyer G, Becattini C et al (2020) 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS). Eur Heart J 41:543–603

    Article  PubMed  Google Scholar 

  9. Armstrong L, Gleeson F, Mackillop L, Mutch S, Beale A (2017) Survey of UK imaging practice for the investigation of pulmonary embolism in pregnancy. Clin Radiol 72:696–701

    Article  CAS  PubMed  Google Scholar 

  10. Rotzinger DC, Dunet V, Ilic V, Hugli OW, Meuli RA, Schmidt S (2020) Pulmonary embolism during pregnancy: a 17-year single-center retrospective MDCT pulmonary angiography study. Eur Radiol 30:1780–1789

    Article  PubMed  Google Scholar 

  11. Gillespie C, Foley S, Rowan M, Ewins K, NiAinle F, MacMahon P (2019) The OPTICA study (Optimised Computed Tomography Pulmonary Angiography in Pregnancy Quality and Safety study): rationale and design of a prospective trial assessing the quality and safety of an optimised CTPA protocol in pregnancy. Thromb Res 177:172–179

    Article  CAS  PubMed  Google Scholar 

  12. Lee C, Kim KP, Bolch WE, Moroz BE, Folio L (2015) NCICT: a computational solution to estimate organ doses for pediatric and adult patients undergoing CT scans. J Radiol Prot 35:891–909

    Article  CAS  PubMed  Google Scholar 

  13. Yuan R, Shuman WP, Earls JP et al (2012) Reduced iodine load at CT pulmonary angiography with dual-energy monochromatic imaging: comparison with standard CT pulmonary angiography–a prospective randomized trial. Radiology 262:290–297

    Article  PubMed  Google Scholar 

  14. Mitchell DP, Rowan M, Loughman E, Ridge CA, MacMahon PJ (2017) Contrast monitoring techniques in CT pulmonary angiography: an important and underappreciated contributor to breast dose. Eur J Radiol 86:184–189

    Article  CAS  PubMed  Google Scholar 

  15. Dronkers CEA, van der Hulle T, Le Gal G et al (2017) Towards a tailored diagnostic standard for future diagnostic studies in pulmonary embolism: communication from the SSC of the ISTH. J Thromb Haemost 15:1040–1043

    Article  CAS  PubMed  Google Scholar 

  16. Van Beek EJ, Brouwers EM, Song B, Stein PD, Ouderk M (2001) Clinical validity of a normal pulmonary angiogram in patients with suspected pulmonary embolism. A Critical Review. Clin Radiol 56:838–842

    Article  PubMed  Google Scholar 

  17. Shahir K, McCrea JM, Lozano LA, Goodman LR (2015) Reduced z-axis technique for CT pulmonary angiography in pregnancy–validation for practical use and dose reduction. Emerg Radiol 22:651–656

    Article  PubMed  Google Scholar 

  18. Shahir K, Goodman LR, Lam CA, Midia EC (2013) Dose reduction of 69% for computed tomography pulmonary angiography: reduced z-axis computed tomography pulmonary angiography retains accuracy in those younger than 40 years. Comput Assist Tomogr 37:765–769

    Article  Google Scholar 

  19. Schmid J, Nagy E, Kaufmann-Bühler AK et al (2022) Diagnosing pulmonary embolism with computed tomography pulmonary angiography. Diagnostic Accuracy of a Reduced Scan Range. J Thorac Imaging 37:323–330

    Article  PubMed  PubMed Central  Google Scholar 

  20. Chan WS, Ray JG, Murray S, Coady GE, Coates G, Ginsberg JS (2002) Suspected pulmonary embolism in pregnancy: clinical presentation, results of lung scanning, and subsequent maternal and pediatric outcomes. Arch Intern Med 162:1170–1175

    Article  CAS  PubMed  Google Scholar 

  21. Astani SA, Davis LC, Harkness BA, Supanich MP, Dalal I (2014) Detection of pulmonary embolism during pregnancy: comparing radiation doses of CTPA and pulmonary scintigraphy. Nucl Med Commun 35:704–711

    Article  PubMed  Google Scholar 

  22. Litmanovich D, Boiselle PM, Bankier AA, Kataoka ML, Pianykh O, Raptopoulos V (2009) Dose reduction in computed tomographic angiography of pregnant patients with suspected acute pulmonary embolism. J Comput Assist Tomogr 33:961–966

    Article  PubMed  Google Scholar 

  23. Halpenny D, Park B, Alpert J et al (2017) Low dose computed tomography pulmonary angiography protocol for imaging pregnant patients: can dose reduction be achieved without reducing image quality? Clin Imaging 44:101–105

    Article  PubMed  Google Scholar 

  24. Hansen SL, de Nijs R, Mortensen J, Berg RMG (2020) Ventilation-perfusion SPECT versus CTPA in young adult females with suspected pulmonary embolism. Eur Respir J 55(6):2000448

  25. Rusandu A, Odegard A, Engh GC, Olerud HM (2019) The use of 80 kV versus 100 kV in pulmonary CT angiography: an evaluation of the impact on radiation dose and image quality on two CT scanners. Radiography (Lond) 25:58–64

    Article  CAS  PubMed  Google Scholar 

  26. Boos J, Kropil P, Lanzman RS et al (2016) CT pulmonary angiography: simultaneous low-pitch dualsource acquisition mode with 70kVp and 40ml of contrast medium and comparison with high-pitch spiral dual-source acquisition with automated tube potential selection. Br J Radiol 89:1062

    Article  Google Scholar 

  27. Godoy MC, Heller SL, Naidich DP et al (2011) Dual-energy MDCT: comparison of pulmonary artery enhancement on dedicated CT pulmonary angiography, routine and low contrast volume studies. Eur J Radiol 79:e11-17

    Article  PubMed  Google Scholar 

  28. De Zordo T, Von Lutterotti K, Dejaco C et al (2012) Comparison of image quality and radiation dose of different pulmonary CTA protocols on a 128-slice CT: high-pitch dual source CT, dual energy CT and conventional spiral CT. Eur Radiol 22:279–286

    Article  PubMed  Google Scholar 

  29. Laqmani A, Regier M, Veldhoen S et al (2014) Improved image quality and low radiation dose with hybrid iterative reconstruction with 80 kV CT pulmonary angiography. Eur J Radiol 83:1962–1969

    Article  PubMed  Google Scholar 

  30. Yılmaz Ö, Üstün ED, Kayan M et al (2013) Diagnostic quality of CT pulmonary angiography in pulmonary thromboembolism: a comparison of three different kV values. Med Sci Monit 19:908–915

    Article  PubMed  PubMed Central  Google Scholar 

  31. Ridge CA, Ni Mhuircheartaigh J, Dodd JD, Skehan SJ (2011) Pulmonary CT angiography protocol adapted to the hemodynamic effects of pregnancy. AJR Am J Roentgenol 197:1058–1063

    Article  PubMed  Google Scholar 

  32. Rose S, Viggiano B, Bour R, Bartels C, Kanne JP, Szczykutowicz TP (2021) Applying a new CT quality metric in radiology: how CT pulmonary angiography repeat rates compare across institutions. J Am Coll Radiol 18:962–968

    Article  PubMed  Google Scholar 

  33. Willemink MJ, Noël PB (2019) The evolution of image reconstruction for CT-from filtered back projection to artificial intelligence. Eur Radiol 29:2185–2195

    Article  PubMed  Google Scholar 

Download references

Acknowledgements

The authors acknowledge Ms Brenda Molloy and the UCD Clinical Research Committee’s assistance with trial set-up and statistical analysis, the Mater Misericordiae University Hospital Data Protection Officer, Mr Ronan O’Halloran for advising on data-access considerations and Dr. Lee and the National Cancer Institute for access to the NCICT software for Monte-Carlo analysis. Furthermore, the authors acknowledge that a small subset of OPTICA’s dataset (20 of 100 CTPAs) was previously analysed with regard to the impact of shielding on breast dose, as per protocol.

Funding

The authors state that this work has not received any funding.

Author information

Authors and Affiliations

  1. Department of Radiology, Mater Misericordiae University Hospital, Whitty Building, North Circular Road, Dublin 7, Dublin, D07 R2WY, Ireland

    Ciara D. Gillespie, Andrew Yates, Mark Hughes, John Hynes, Mark C. Murphy, John Varden, Ferdia Bolster & Peter J. MacMahon

  2. Department of Haematology, Mater Misericordiae University Hospital, Dublin, D07 R2WY, Ireland

    Karl Ewins & Fionnuala NíAinle

  3. Department of Obstetrics, Rotunda Hospital, Dublin, D01 P5W9, Ireland

    Gabriella McMahon & Jennifer Donnelly

  4. Clinical Research Centre, School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland

    Marie Galligan, Sebastian Vencken & Ekele Alih

  5. School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland

    Jennifer Donnelly, Ferdia Bolster, Fionnuala NíAinle & Peter J. MacMahon

  6. Department of Medical Physics, St James Hospital, Dublin, D08 NHY1, Ireland

    Michael Rowan

  7. Radiography & Diagnostic Imaging, School of Medicine, University College Dublin, Dublin, D04 V1W8, Ireland

    Shane Foley

Authors
  1. Ciara D. Gillespie
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Andrew Yates
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Mark Hughes
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Karl Ewins
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Gabriella McMahon
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. John Hynes
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Mark C. Murphy
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Marie Galligan
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Sebastian Vencken
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Ekele Alih
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. John Varden
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Jennifer Donnelly
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. Ferdia Bolster
    View author publications

    You can also search for this author in PubMed Google Scholar

  14. Michael Rowan
    View author publications

    You can also search for this author in PubMed Google Scholar

  15. Shane Foley
    View author publications

    You can also search for this author in PubMed Google Scholar

  16. Fionnuala NíAinle
    View author publications

    You can also search for this author in PubMed Google Scholar

  17. Peter J. MacMahon
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Ciara D. Gillespie.

Ethics declarations

Guarantor

The scientific guarantor of this publication is the principal investigator Professor Peter MacMahon.

Conflict of interest

The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.

Statistics and biometry

The UCD Clinical Research Committee kindly provided statistical advice for this manuscript and the authors include a biostatistician.

Informed consent

Written informed consent was obtained from all subjects (patients) in this study.

Ethical approval

Institutional Review Board approval was obtained at Mater Misericordiae University Hospital, Dublin, Ireland.

Study subjects or cohorts overlap

A small subset of OPTICA’s dataset (20 of 100 CTPAs) was previously analysed and reported with regard to the impact of shielding on breast dose [1]. This was planned as part of the study and laid out in our published protocol [2]. Breast shielding was not implemented in the remaining 80 CTPAs in part due to concerns regarding cross-contamination in the context of the pandemic.

1. Gillespie CD, Yates A, Murphy MC, Hughes M, Ewins K, NíAinle F, Bolster F, Rowan M, Foley S, MacMahon PJ. Breast shielding combined with an optimized computed tomography pulmonary angiography pregnancy protocol: a special use-case for shielding? J Thorac Imaging 2023;38(1):36–43. https://doi.org/10.1097/rti.0000000000000677.

2. Gillespie C, Foley S, Rowan M, Ewins K, NiAinle F, MacMahon P. The OPTICA study (Optimised Computed Tomography Pulmonary Angiography in Pregnancy Quality and Safety study): rationale and design of a prospective trial assessing the quality and safety of an optimised CTPA protocol in pregnancy. Thrombosis research 2019;177:172–179. https://doi.org/10.1016/j.thromres.2019.03.007.

Methodology

• prospective

• observational

• performed at one institution.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Gillespie, C.D., Yates, A., Hughes, M. et al. Validating the safety of low-dose CTPA in pregnancy: results from the OPTICA (Optimised CT Pulmonary Angiography in Pregnancy) Study. Eur Radiol (2024). https://doi.org/10.1007/s00330-024-10593-y

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/s00330-024-10593-y

Keywords

Search

Navigation