Benefit of Hybrid Rooms

Pr Stephan Haulon, CHU Lille Aortic Center, France

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Disclosures

Research support, Consulting, IP• Cook Med, GE Healthcare

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EVAR procedures in the Hybrid Room

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Outcomes for EVAR procedures at CHU LilleLiterature overview

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Operator dose at CHU Lille

Operator exposure over the lead apron

per procedure typec

The limit for occupational exposure suggested by the ICRP is maximal 50 mSv/yeard.

a. Patel A.P. et al, Occupational Radiation Exposure During Aortic Procedures, Eur J Vasc Endovasc Surg. 2013 Oct;46(4):424-30b. G. Panuccio at al. Comparison of indirect radiation dose estimates with directly measured radiation dose for patients and operators during complex endovascular procedures. J Vasc Surg 2011;53:885-94. c. Hertault A et al. Impact of Hybrid Rooms with Image Fusion on Radiation Exposure duringEndovascular Aortic Repair, Eur J Vasc Endovasc Surg. 2014 Oct;48(4):382-90. d. International Commission on Radiological Protection, 1990. Recommendationsof the International Commission on Radiological Protection. ICRP Publication 60. Ann ICRP 1991.

How do we achieve this low radiation dose?

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Hybrid room with angiography systems

Any image frame is automatically analyzed by AutoEx AI algorithm to select the best exposure parameters to optimize CNR, based on the estimated patient thickness.

Detector High Detective Quantum Efficiency DQE Auto Exposure Management

dose versus image quality and all detector components are summarized into DQE

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Optimize system geometry

Haqqani J Vasc Surg 2012

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Optimize system geometry

InnovaSense patient contouring automatically positions the detector as close as possible to the patient

1. Retrospective analysis of 956 patient rom one-year usage (2013) of PCI activities on Innova IGS520 at CHU Brest. Simulated with the user working at max SID (120cm) instead of optimized SID obtained with InnovaSense

Air Kerma Dose Reduction by up to 25%

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A

B

C

Limit C-arm angulation

When LAO/RAO angle are >30°,patient & operator dose rate increases exponentially.

Same with CRA/CAU >15°

LAO/RAOOperator Dose rate

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Use lowest acceptable protocol and frame rate

100%

50%

24%

9%5% 2%

IQ+Normal30fps

IQ+Normal15fps

RDL+Normal15fps

RDL+Low

15fps

RDL+Low

7.5fps

RDLLow

3.75fps

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Before the procedure

EVAR ASSIST 2 planning to define ostia contours & best working angulations

3D Volumes preparation for Image Fusion

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Planning automatically exported to the Discovery C-arm

3D overlay

Planned Landing zones

Ostia contours

Optimized C-arm angulations

Planning on CT AngioCT Angio fused with fluoroscopy

Recall of C-arm angulations from table-side

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Routinely use image fusion : reposition anatomy without fluoro

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Automatic reposition of table and gantry without fluoroscopy using preset working views

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Avoid Magnification, Use large FOV + Collimation

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Routinely use image fusion: use digital zoom, not magnification

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Limit DSA runs, use Fluoroscopy

In term of dose, 1 DSA image ~ 500 fluoro images

Prefer fluoroscopy instead of DSA, except for completion angio or difficult situations

Could these results be achievable elsewhere?

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REVAR study

Methodology

• Bifurcated EVAR

• 6 centers worldwide using same Hybrid Room

(Discovery IGS from GE Healthcare)

• Each center has received a dose and fusion

imaging training before enrolling patients

• Monitoring dose and practice via Dosewatch,

cloud-based tracking system

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Pre study Result : The Importance of practice feedbacks

Site X prior to the study

DAP is correct but large room for improvement! increase collimation usage

Avoid magnification

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After Practice analysis and dedicated training…

32%

68%

Fluoro DSA

100%

7,5

100%

30

19%81%

8%

74%

18%

30

0% 20% 40% 60% 80% 100%

Irradiated

Collimated

Acquisition Type (% of Total DAP)

Frame Rate(% of Total DAP)

Angulation(% of Fluoro Time & DAP)

FOV

(% of Total DAP)

Collimation (% of estimated collimated area per FOV)Number Of Cases 8

MeanDAP 16.5Gy.cm²

MeanAK 0.105Gy

Mean Fluoro Time 14.05 min

Mean SID 1.15 m

… DAP divided by 2 thanks to better FOV & Collimation management

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0 50 100 150 200

Site 1

Site 2

Site 3

Site 4

Median Air Kerma (mGy)

0 500 1000 1500 2000 2500

Site 1

Site 2

Site 3

Site 4

Median DAP (cGy.cm2)

0 200 400 600 800 1000 1200

Site 1

Site 2

Site 3

Site 4

Median Fluoro time (sec)

REVAR study preliminary results

Achieving consistent low dose results across sitesMedian AK < 200 mGy, DAP < 25 Gycm2

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Intra-op CBCT assessment

Median radiation exposure of CBCTa is 7 Gy.cm2

a. *Hertault A et al. Benefits of Completion 3D Angiography Associated with Contrast Enhanced Ultrasound to Assess Technical Success after EVAR, Eur J Vasc Endovasc Surg (2015)

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Intra-op CBCT assessment

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FEVAR in Chronic Dissections

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Tear inflation

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Conclusion

• Low dose technologies enabled by modern hybrid ORs, associated with good practices, has a huge impact on low dose results

• Integrated workflow of EVAR ASSIST from sizing to CBCT including fusion imaging reduces total dose throughout patients’ hospital stay

• Routine use of fusion imaging with full control at table side enables to achieve low dose results and high technical success