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Neuroimaging
Original research
Diagnostic quality and accuracy of low dose 3D-DSA protocols in the evaluation of intracranial aneurysms
  1. Monica S Pearl1,
  2. Collin Torok2,
  3. Zinovy Katz1,
  4. Steven A Messina2,
  5. Jordi Blasco3,
  6. Rafael J Tamargo4,
  7. Judy Huang4,
  8. Richard Leigh5,
  9. Steven Zeiler5,
  10. Martin Radvany1,
  11. Tina Ehtiati6,
  12. Philippe Gailloud1
  1. 1Division of Interventional Neuroradiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
  2. 2Division of Neuroradiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
  3. 3Neurointerventional Department C.D.I, Hospital Clinic of Barcelona, Barcelona, Spain
  4. 4Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
  5. 5Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
  6. 6Siemens Corporate Research, Baltimore, Maryland, USA
  1. Correspondence to Dr Monica S Pearl, Division of Interventional Neuroradiology, The Johns Hopkins Hospital, 1800 Orleans Street, Bloomberg Building, 7218, Baltimore, MD 21287, USA; msmit135{at}jhmi.edu

Abstract

Background 3D-DSA is the ‘gold standard’ imaging technique for the diagnosis and characterization of intracranial aneurysms.

Objective To compare the image quality and accuracy of low dose 3D-DSA protocols in patients with unruptured intracranial aneurysms.

Materials and methods The standard manufacturer 5 s 0.36 μGy/f protocol and one of three low dose 3D-DSA protocols (5 s 0.10 μGy/f, 5 s 0.17 μGy/f, 5 s 0.24 μGy/f) were performed in 12 patients with unruptured intracranial aneurysms. Three interventional neuroradiologists, two neurosurgeons, and two neurologists rated the image quality of all 3D reconstructions as good, acceptable, or poor. Three interventional neuroradiologists measured two dimensions of each aneurysm for all protocols. The radiation dose metric Ka,r (reference point air kerma, in mGy) was recorded for each 3D-DSA protocol.

Results The standard 5 s 0.36 μGy/f protocol earned the highest average subjective rating of 2.76, followed by the 5 s 0.24 μGy/f (2.72), and 5 s 0.17 μGy/f (2.59) protocols. The ranges of differences in aneurysm measurements between the 5 s 0.24 μGy/f protocol and the standard were <0.5 mm. The median Ka,r metrics for each protocol were as follows: 5 s 0.36 μGy/f (89.0 mGy), 5 s 0.24 μGy/f (57.7 mGy), 5 s 0.17 μGy/f (45.9 mGy), and 5 s 0.10 μGy/f (27.6 mGy).

Conclusions Low dose 3D-DSA protocols with preserved image quality are achievable, and can help reduce exposure of patients and operators to unnecessary radiation. The 5 s 0.24 μGy/f protocol generates one-third smaller radiation dose than the standard 5 s 0.36 μGy/f protocol without compromising diagnostic image quality or accuracy.

  • Aneurysm
  • Angiography
  • Technique

https://doi.org/10.1136/neurintsurg-2014-011137

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    Introduction

    DSA is the ‘gold standard’ imaging method for evaluating patients with subarachnoid hemorrhage (SAH) and intracranial aneurysms.1–6 Treatment of aneurysm-related SAH with diagnostic DSA and embolization, however, potentially exposes patients and operators to high doses of radiation.7–17 Cumulative doses for these patients have been reported to range from 1 to 12.8 Gy, which are comparable to doses known to result in severe late secondary skin injury and delayed neoplasia.7–9 ,11 ,12 ,14 ,15 ,18 ,19 In accordance with the radiation safety philosophy of ALARA (as low as reasonably achievable), imaging protocols and operator knowledge of fluoroscopic principles should be optimized to limit the exposure of patients and staff to radiation.20

    Defining aneurysm location and morphology, including the projection, neck, and relationship to neighboring and parent arteries, is vital for endovascular and neurosurgical interventions. Three-dimensional DSA (3D-DSA) and 3D volume rendered reconstructions are instrumental in elucidating these critical features and are valuable for reducing radiation dose, injected contrast volume, and procedure time.21 ,22 Patient radiation dose for 3D-DSA has been reported to be significantly lower than for biplanar DSA, by nearly four times in peak skin dose and 40% lower in cumulative dose.22 The information provided by 3D-DSA obviates the need for multiple DSA runs to evaluate the aneurysm and for determining optimal working projections.3 Moreover, 3D-DSA is more reliable for the detection of additional aneurysms that might be overlooked by 2D-DSA, particularly aneurysms <3 mm in maximum diameter.23 ,24

    Guidelines have been created by the US Food and Drug Administration International Commission on Radiologic Protection and the National Cancer Institute for monitoring operator and patient maximal doses, including physician training to reduce potential injury to patients and operators from radiation exposure.25 ,26 More recently, attention has been devoted to screening, preventing, and dealing with fluoroscopic sentinel events during neuroendovascular procedures, with an emphasis on the interventionalist's responsibility for reducing radiation exposure to patients and staff.27 This further underscores the need for the design and implementation of protocols and techniques that maintain diagnostic image quality while reducing radiation exposure.20 We hypothesized that low dose 3D-DSA protocols in the evaluation of patients with intracranial aneurysms reduce radiation exposure while preserving diagnostic image quality in comparison with standard manufacturer 3D-DSA settings.

    Materials and methods

    All patients gave written informed consent to participate in this institutional review board approved study. Three low dose 3D-DSA protocols (5 s 0.24 μGy/f, 5 s 0.17 μGy/f, 5 s 0.10 μGy/f) were chosen based on a previous study,28 and compared against the standard manufacturer 5 s 0.36 μGy/f 3D-DSA setting in 12 patients with unruptured intracranial aneurysms. The standard and one of three low dose 3D-DSA protocols were performed in each patient. Parameters for each 3D-DSA protocol including tube voltage (kV), tube current (mA), and pulse width (ms) are listed in table 1. All 3D-DSA protocols used the following acquisition parameters: 1.5°/f, 133 images, 30f/s, and 4.4 s. Copper beam filtration was not applied. All examinations were performed on a clinical biplane system (Artis Zee, Siemens Medical Solutions, Erlangen, Germany).

    View this table:
    Table 1

    Patient demographics and 3D-DSA settings

    Multiplanar 2D and 3D reconstructions were created for all aneurysms and all protocols by an interventional neuroradiologist (MSP), not involved in the subjective or quantitative analysis and blinded to the specific protocol. The Ka,r (reference point air kerma) obtained from the manufacturer-generated examination protocol was recorded in mGy for each 3D-DSA protocol.

    Subjective image quality assessment: low dose versus standard

    Reconstructed 3D images of each aneurysm were subjectively evaluated by a group of interventional neuroradiologists (ZK, JB, PG), cerebrovascular neurosurgeons (JH, RFT), and stroke neurologists (RL, SZ). All reconstructions were assessed for image quality and rated as good, acceptable, or poor, and assigned corresponding values of 3, 2, or 1, respectively. Poor quality images were considered unacceptable for clinical use.

    Statistical analysis

    A non-parametric paired signed rank test was performed to determine if quality assessments for the lower dose images were consistently different from those of the standard dose images. A parametric mixed model analysis was performed to take into account multiple raters evaluating multiple images, including images from the same patients, for the standard and low dose protocols. The ratings were considered as continuous variables, the raters and patients were considered as crossed random effects, and the average assessment scores for various protocols were calculated.

    Protocol identification: low dose (0.24 μGy/f) versus standard (0.36 μGy/f)

    Randomly ordered 3D reconstructed images from the 5 s 0.24 μGy/f and 5 s 0.36 μGy/f protocols (four patients, eight images in total) were presented to all raters, who were asked to determine if the image shown was generated by a standard or low dose protocol.

    Statistical analysis

    An unadjusted analysis of agreement was performed as a κ statistic. A parametric mixed model analysis was also performed, taking into account individual patients contributing multiple images and raters contributing multiple assessments. A crossed random-effects model was used with the classification by the raters taken as a continuous variable.

    Quantitative aneurysm measurement: low dose versus standard

    Using 2D multiplanar reconstructions, three interventional neuroradiologists (ZK, JB, PG) measured the anterior–posterior and transverse dimensions of each aneurysm for all protocols in all patients.

    Statistical analysis

    A clinically acceptable difference in aneurysm measurements obtained between the standard and each low dose protocol was defined as <0.5 mm, reflecting the smallest available coil size increment. Multiple measurements by each rater were not performed owing to the previously demonstrated high intraclass correlation coefficient on the preceding animal study.28 An intraclass correlation coefficient was calculated.

    Results

    A standard and one of the three low dose 3D-DSA protocols were performed in each of the 12 patients with 12 unruptured intracranial aneurysms for a total of 24 3D-DSA datasets (figures 1⇓–3). Aneurysms were predominantly located in the anterior circulation (n=11), and aneurysm size ranged from 2.1×1.5 mm to 7.6×4.8 mm.

    Figure 1
    Figure 1

    Reconstructed 3D-DSA images from subjects 1–4 (subject number on bottom left of each image) show preserved image quality in the low dose 5 s 0.24 μGy/f images (bottom) in comparison with their corresponding standard 5 s 0.36 μGy/f images (top).

    Figure 2
    Figure 2

    3D-DSA reconstructed images from subjects 5–8 (subject number on bottom left of each image) show acceptable image quality in the low dose 5 s 0.17 μGy/f images (bottom) in comparison with the standard 5 s 0.36 μGy/f images (top).

    Figure 3
    Figure 3

    Reconstructed 3D-DSA images from subjects 9–12 (subject number on bottom left of each image) show inferior image quality in the low dose 5 s 0.10 μGy/f images (bottom) in comparison with the standard 5 s 0.36 μGy/f images (top). Images generated with this low dose protocol accounted for more than two-thirds of the unacceptable image quality ratings.

    General subjective image quality assessment: low dose versus standard

    All seven raters evaluated the standard and low dose images in all 12 patients for a total number of 168 ratings (84 ratings for the 5 s 0.36 μGy/f images; 28 ratings for each of the low dose groups). The numbers of good, acceptable, and poor ratings were 110, 47, and 11, respectively. The 5 s 0.36 μGy/f protocol achieved the highest average subjective rating of 2.76, closely followed by the 5 s 0.24 μGy/f (average rating of 2.72) and 5 s 0.17 μGy/f (average rating of 2.59) protocols. The 5 s 0.10 μGy/f protocol scored the lowest average rating of 1.94 and accounted for eight of the 11 ‘poor’ ratings. A non-parametric paired signed rank test was used to calculate the following p values to evaluate the perceived differences between the standard and the low dose protocols: 5 s 0.36 μGy/f versus 5 s 0.24 μGy/f (p=0.71), 5 s 0.36 μGy/f vs 5 s 0.17 μGy/f (p=0.01), 5 s 0.36 μGy/f vs 5 s 0.10 μGy/f (p=0.002). There was no significant difference between the 5 s 0.36 μGy/f and 5 s 0.24 μGy/f protocols, whereas a significant difference was found between the 5 s 0.36 μGy/f protocol and the other two low dose protocols.

    A parametric mixed model analysis was performed and showed no significant difference between the 5 s 0.36 μGy/f and 5 s 0.24 μGy/f protocols, and a significant linear trend between average assessments scores and the protocol dose (increasing score with increasing dose per frame).

    Low dose versus standard: 0.24 μGy/f versus 0.36 μGy/f protocol identification

    The same seven raters categorized eight 3D reconstructed images from four patients as either standard or low dose images for a total of 56 classifications. The raters more often thought the images were generated by the standard protocol, considering this to be true for 33 of the 56 reconstructions.

    The expected agreement by chance was 50%. The observed agreement was 60% (κ=0.18, p=0.1018), indicating poor agreement between the actual 3D-DSA protocol and the readers’ identification of the protocol. The parametric mixed model analysis demonstrated a non-significant (p=0.187) association of the raters’ classification with the actual protocol, indicating that the image quality differences between the 5 s 0.36 μGy/f and the 5 s 0.24 μGy/f low dose protocol were not reliably perceptible.

    Low dose versus standard: quantitative aneurysm measurement assessment

    Three interventional neuroradiologists (ZK, JB, PG) measured the anterior–posterior and transverse dimensions of each aneurysm for all protocols in all 12 patients for a total of 144 measurements. The ranges of differences in measurements (in mm) for each low dose protocol relative to the standard were 5 s 0.24 μGy/f (0.33–0.39); 5 s 0.17 μGy/f (0.47–0.60); 5 s 0.10 μGy/f (0.71–0.74). Values in the 0.24 μGy/f group were within the threshold for a clinically acceptable difference, defined as <0.5 mm. The range of values for the 5 s 0.17 μGy/f protocol extended above this threshold. The greatest measured difference was found in the 5 s 0.10 μGy/f group, with the range of values entirely above the threshold defined as clinical acceptable. The intraclass correlation coefficient (0.970, p<0.001) indicated high inter-rater reliability.

    Reference point air kerma (Ka,r)

    The Ka,r for all 3D-DSA protocols ranged from 26.6 mGy to 101.2 mGy. The median and ranges (in mGy) of Ka,r per protocol were as follows: 5 s 0.36 μGy/f (89.0; 73.0–101.2); 5 s 0.24 μGy/f (57.7; 50.0–69.4); 5 s 0.17 μGy/f (45.9; 36.6–53.8); 5 s 0.10 μGy/f (27.6; 26.6–31.8). The median delivered dose from the 5 s 0.24 μGy/f protocols was 35% less than the delivered dose from the 5 s 0.36 μGy/f setting. All protocols showed a significant difference in the dose of radiation delivered compared with the standard protocol, p<0.001.

    Discussion

    Fluoroscopy-guided endovascular procedures are an important source of radiation exposure for patients and operators. Repetitive irradiation during the care of patients with aneurysmal SAH has been shown to result in significant cumulative radiation doses, accounting for up to 87% of the total radiation exposure associated with neurointerventional procedures.19 The long-term stochastic effects for these patients remain unknown; however, the deterministic effects of radiation, including skin epilation, erythema, and desquamation when doses exceed 3 Gy, 6 Gy, and 15 Gy, respectively,8 ,29 are better recognized.30 Radiation exposure during endovascular procedures should be reduced as much as possible and this can be achieved by tailoring examination protocols to each patient and indication, and by following basic principles of radiation protection.20 Simple fluoroscopy techniques can result in a significant dose reduction without compromising procedural safety.30 Creating lower dose 3D-DSA protocols, as shown in this study, can further aid in reducing the radiation dose delivered while maintaining diagnostic accuracy.

    This study shows the feasibility of significantly reducing delivered radiation doses with low dose 3D-DSA protocols while maintaining diagnostic image quality and accuracy. The median Ka,r from the 5 s 0.24 μGy/f protocol was 35% less than that of the 5 s 0.36 μGy/f setting. The images generated from this low dose protocol were indiscernibly different from those obtained with the standard protocol. Furthermore, mean differences in aneurysm measurements between the two groups were below the predefined clinically acceptable limit of 0.5 mm.

    The 5 s 0.17 μGy/f protocols created clinically acceptable images with an average subjective rating of 2.59; however, some of the differences in measured aneurysm dimensions (range 0.49–0.60) were above the clinically acceptable threshold of 0.5 mm. Although not to be used in the initial diagnostic evaluation, this protocol might be appropriate for follow-up and for identifying the best working angles for intervention. The benefits of an average 48% reduction in Ka,r by this protocol must be considered in the above-mentioned scenarios and particularly in serially imaged patients.

    The median Ka,r from the 5 s 0.10 μGy/f protocols was 69% less than the delivered dose of the standard protocol. However, image quality was consistently inferior to that of the other low dose protocols and this protocol accounted for 73% of the images classified as unacceptable for clinical use. This group also produced the greatest measured differences in comparison with the standard protocol, and in particular, the range of values was entirely above the clinically acceptable threshold.

    Despite the limitations of a relatively small sample size and predominance of anterior circulation aneurysms, our results indicate the feasibility and applicability of lower dose 3D-DSA protocols in the evaluation of patients with intracranial aneurysms. Given that aneurysm management has been shown to contribute the majority of radiation exposure associated with neurointerventional procedures, we conclude that these findings are clinically relevant and can serve as a basis for further investigation aiming at providing the best treatment at the lowest radiation possible.

    Conclusion

    Low dose 3D-DSA protocols with preserved image quality are achievable, and can help to reduce unnecessary exposure to radiation of both patients and operators. The 5 s 0.24 μGy/f protocol can be considered as a reliable substitute for the standard 5 s 0.36 μGy/f protocol, generating one-third smaller radiation dose without compromising diagnostic image quality or accuracy.

    References

    1. ↵
      1. Gauvrit JY,
      2. Leclerc X,
      3. Vermandel M,
      4. et al
      . 3D rotational angiography: use of propeller rotation for the evaluation of intracranial aneurysms. AJNR Am J Neuroradiol 2005;26:163–5.
      OpenUrlAbstract/FREE Full Text
    2. ↵
      1. Hochmuth A,
      2. Spetzger U,
      3. Schumacher M
      . Comparison of three-dimensional rotational angiography with digital subtraction angiography in the assessment of ruptured cerebral aneurysms. AJNR Am J Neuroradiol 2002;23:1199–205.
      OpenUrlAbstract/FREE Full Text
    3. ↵
      1. Abe T,
      2. Hirohata M,
      3. Tanaka N,
      4. et al
      . Clinical benefits of rotational 3D angiography in endovascular treatment of ruptured cerebral aneurysm. AJNR Am J Neuroradiol 2002;23:686–8.
      OpenUrlAbstract/FREE Full Text
    4. ↵
      1. Sugahara T,
      2. Korogi Y,
      3. Nakashima K,
      4. et al
      . Comparison of 2D and 3D digital subtraction angiography in evaluation of intracranial aneurysms. AJNR Am J Neuroradiol 2002;23:1545–52.
      OpenUrlAbstract/FREE Full Text
    5. ↵
      1. van Rooij WJ,
      2. Sprengers ME,
      3. de Gast AN,
      4. et al
      . 3D rotational angiography: the new gold standard in the detection of additional intracranial aneurysms. AJNR Am J Neuroradiol 2008;29:976–9. doi:10.3174/ajnr.A0964
      OpenUrlAbstract/FREE Full Text
    6. ↵
      1. Anxionnat R,
      2. Bracard S,
      3. Ducrocq X,
      4. et al
      . Intracranial aneurysms: clinical value of 3D digital subtraction angiography in the therapeutic decision and endovascular treatment. Radiology 2001;218:799–808. doi:10.1148/radiology.218.3.r01mr09799
      OpenUrlCrossRefPubMedWeb of Science
    7. ↵
      1. Struelens L,
      2. Vanhavere F,
      3. Bosmans H,
      4. et al
      . Skin dose measurements on patients for diagnostic and interventional neuroradiology: a multicentre study. Radiat Prot Dosimetry 2005;114:143–6. doi:10.1093/rpd/nch537
      OpenUrlAbstract/FREE Full Text
    8. ↵
      1. Mooney RB,
      2. McKinstry CS,
      3. Kamel HA
      . Absorbed dose and deterministic effects to patients from interventional neuroradiology. BJR2000;73:745–51.
      OpenUrlPubMed
    9. ↵
      1. Bergeron P,
      2. Carrier R,
      3. Roy D,
      4. et al
      . Radiation doses to patients in neurointerventional procedures. AJNR Am J Neuroradiol 1994;15:1809–12.
      OpenUrlAbstract/FREE Full Text
    10. ↵
      1. Bor D,
      2. Cekirge S,
      3. Turkay T,
      4. et al
      . Patient and staff doses in interventional neuroradiology. Radiat Prot Dosimetry 2005;117:62–8. doi:10.1093/rpd/nci725
      OpenUrlAbstract/FREE Full Text
    11. ↵
      1. D'Ercole L,
      2. Mantovani L,
      3. Thyrion FZ,
      4. et al
      . A study on maximum skin dose in cerebral embolization procedures. AJNR Am J Neuroradiol 2007;28:503–7.
      OpenUrlAbstract/FREE Full Text
    12. ↵
      1. Gkanatsios NA,
      2. Huda W,
      3. Peters KR
      . Adult patient doses in interventional neuroradiology. Med Phys 2002;29:717–23. doi:10.1118/1.1470206
      OpenUrlCrossRefPubMed
    13. ↵
      1. Layton KF,
      2. Kallmes DF,
      3. Cloft HJ,
      4. et al
      . Radiation exposure to the primary operator during endovascular surgical neuroradiology procedures. AJNR Am J Neuroradiol 2006;27:742–3.
      OpenUrlAbstract/FREE Full Text
    14. ↵
      1. O'Dea TJ,
      2. Geise RA,
      3. Ritenour ER
      . The potential for radiation-induced skin damage in interventional neuroradiological procedures: a review of 522 cases using automated dosimetry. Med Phys 1999;26:2027–33. doi:10.1118/1.598718
      OpenUrlCrossRefPubMed
    15. ↵
      1. Theodorakou C,
      2. Horrocks JA
      . A study on radiation doses and irradiated areas in cerebral embolisation. BJR 2003;76:546–52. doi:10.1259/bjr/26353198
      OpenUrlPubMed
    16. ↵
      1. Vano E,
      2. Faulkner K
      . ICRP special radiation protection issues in interventional radiology, digital and cardiac imaging. Radiat Prot Dosimetry 2005;117:13–7. doi:10.1093/rpd/nci702
      OpenUrlAbstract/FREE Full Text
    17. ↵
      1. Vano E,
      2. Gonzalez L,
      3. Guibelalde E,
      4. et al
      . Evaluation of risk of deterministic effects in fluoroscopically guided procedures. Radiat Prot Dosimetry 2005;117:190–4. doi:10.1093/rpd/nci714
      OpenUrlAbstract/FREE Full Text
    18. ↵
      1. Miller DL,
      2. Balter S,
      3. Cole PE,
      4. et al
      . Radiation doses in interventional radiology procedures: the RAD-IR study: part I: overall measures of dose. J Vasc Interv Radiol 2003;14:711–27. doi:10.1097/01.RVI.0000079980.80153.4B
      OpenUrlCrossRefPubMedWeb of Science
    19. ↵
      1. Moskowitz SI,
      2. Davros WJ,
      3. Kelly ME,
      4. et al
      . Cumulative radiation dose during hospitalization for aneurysmal subarachnoid hemorrhage. AJNR Am J Neuroradiol 2010;31:1377–82. doi:10.3174/ajnr.A2132
      OpenUrlAbstract/FREE Full Text
    20. ↵
      1. Pearl MS,
      2. Torok C,
      3. Wang J,
      4. et al
      . Practical techniques for reducing radiation exposure during cerebral angiography procedures. J Neurinterv Surg 2015;7:141–5.
    21. ↵
      1. Beck J,
      2. Rohde S,
      3. Berkefeld J,
      4. et al
      . Size and location of ruptured and unruptured intracranial aneurysms measured by 3-dimensional rotational angiography. Surg Neurol 2006;65:18–25; discussion-7. doi:10.1016/j.surneu.2005.05.019
      OpenUrlCrossRefPubMed
    22. ↵
      1. Schueler BA,
      2. Kallmes DF,
      3. Cloft HJ
      . 3D cerebral angiography: radiation dose comparison with digital subtraction angiography. AJNR Am J Neuroradiol 2005;26:1898–901.
      OpenUrlAbstract/FREE Full Text
    23. ↵
      1. Kucukay F,
      2. Okten RS,
      3. Tekiner A,
      4. et al
      . Three-dimensional volume rendering digital subtraction angiography in comparison with two-dimensional digital subtraction angiography and rotational angiography for detecting aneurysms and their morphological properties in patients with subarachnoid hemorrhage. Eur J Radiol 2012;81:2794–800. doi:10.1016/j.ejrad.2011.10.006
      OpenUrlPubMed
    24. ↵
      1. Shi WY,
      2. Li YD,
      3. Li MH,
      4. et al
      . 3D rotational angiography with volume rendering: the utility in the detection of intracranial aneurysms. Neurology India 2010;58:908–13. doi:10.4103/0028-3886.73743
      OpenUrlPubMed
    25. ↵
      The 2007 Recommendations of the International Commission on Radiological Protection. ICRP publication 103. Ann ICRP 2007;37:1–332.
      OpenUrlFREE Full Text
    26. ↵
      1. Miller DL
      . Interventional fluoroscopy: reducing radiation risks for patients and staff. J Vasc Interv Radiol 2009;20(7 Suppl):S274. doi:10.1016/j.jvir.2009.04.057
      OpenUrlCrossRefPubMedWeb of Science
    27. ↵
      1. Vance AZ,
      2. Weinberg BD,
      3. Arbique GM,
      4. et al
      . Fluoroscopic sentinel events in neuroendovascular procedures: how to screen, prevent, and address occurrence. AJNR Am J Neuroradiol 2013;34:1513–5. doi:10.3174/ajnr.A3185
      OpenUrlAbstract/FREE Full Text
    28. ↵
      1. Pearl MS,
      2. Torok CM,
      3. Messina SA,
      4. et al
      . Reducing radiation dose while maintaining diagnostic image quality of cerebral three-dimensional digital subtraction angiography: an in vivo study in swine. J Neurointerv Surg 2014;6:672–6.
    29. ↵
      1. Norbash AMBD,
      2. Marks MP
      . Techniques for reducing interventional neuroradiologic skin dose: tube position rotation and supplemental beam filtration. AJNR Am J Neuroradiol 1996;17:41–9.
      OpenUrlAbstract
    30. ↵
      1. Wagner LK,
      2. Eifel PJ,
      3. Geise RA
      . Potential biological effects following high X-ray dose interventional procedures. J Vasc Interv Radiol 1994;5:71–84. doi:10.1016/S1051-0443(94)71456-1
      OpenUrlCrossRefPubMedWeb of Science

    Footnotes

    • Scientific Paper presented at the 50th Annual American Society of Neuroradiology Meeting, New York, NY, April 26, 2012.

    • Contributors All authors listed have contributed appropriately to satisfy criteria for authorship.

    • Funding Support for this work was provided by research grants from Siemens Corporate Research.

    • Competing interests None.

    • Ethics approval Institutional review board.

    • Provenance and peer review Not commissioned; externally peer reviewed.