Cone Beam CT

Room and Patient Setup

• Light sedation vs local only – important for breath holding
• Coach patient on breathing in preprocedural area
• IV location: left arm, away from elbow or locations predisposed to kinking
• BP cuff: left arm or on leg
• Arms by side but not tucked or restrained to allow for quick arms-up position
• C-arm position: left side of patient (as opposed to prop spin) - helps avoid C-arm getting caught on tubes and lines
• Femoral access may be easier for some operators

Cone-Beam CT Parameters

• Motion trumps photons
• Choose spin with shortest acquisition time
• Low-dose spins may provide better pictures than high dose/high quality spin because of shorter acquisition times
• Breath hold on end expiration

Injection Tips

• Suggests below were taken from Episode 51 - Cone Beam CT Techniques
• Delay time: time from contrast injection to spin acquisition beginning
• 8 second delay for mCRC – parenchymal phase
• Goal: injections with antegrade flow without reflux

Dr. Bourgeois’ approximate injections for right and left lobe:
• Dr. Bourgeois’ approximate right hepatic artery: 2.5 mL/s for 25 ml (or 2.0 for 20)
• Dr. Bourgeois’ approximate left hepatic artery: 1 mL/s for 10 ml (or 1.5 for 15)
• Shorter delay times between 2-4 seconds if interested in arterial anatomy or hypervascular tumors

Dr. Beck's approximate injections for right and left lobe:
• Injection rates for mCRC: RHA: 2 ml/s for 22 mL with 6 second delay
• Injection rates for mCRC: LHA: 1 ml/s for 11 mL with 6 second delay

Equipment

• Microcatheter
• High Pressure: 1200 PSI
• Shorter length allows for slightly better flow rates
• 130cm length as opposed to 150 cm from wrist
• If using shorter endhole catheter (65 cm instead of 80 cm), can try using 110 cm microcatheter

Contrast

• Contrast dilution: typically 50:50 dilution
• Examples: 50 mL contrast and 50 cc normal saline
• Agitate contrast mixture occasionally so that saline and contrast mix well