How to Deliver Suitable MR and CT Data for Catheterization Overlay
Jason N. Johnson MD MHS
Director, Cardiac MRIAssociate Professor of Pediatrics and RadiologyUniversity of Tennessee Health Sciences Center
Le Bonheur Children’s HospitalSt. Jude Children’s Research Hospital
Disclosure Statement
• Consultant for Abbott
Outline
• Imaging acquisition– MR– CT
• Segmentation• Registration• Visualization
Not all examples tetralogy of Fallot
RoadmappingDevice
positioning
Radiation reduction
Utility of MR Fusion
InterventionalPlanning
Camera angleselection
Multimodality Fusion - Workflow
MRI / CT acquisition
Registration to Fluoro
Visualization
IMAGE ACQUISITION
Time-resolved angiography (TWIST, TRICKS, TRAK, Freeze Frame)
3D MRA technique with very high temporal (sub-second) resolution which will allow to capture the arterial,
mixed and venous phase images during the passage of a contrast agent through the vascular anatomy
✔ Good temporal resolution (sub-second) allows for separating right and left side
✖ Not gated
✖ Lower spatial resolution (sub-millimeter)
MRI acquisition Registration Visualization
MRA Acquisition
Parameter: TR 3 ms, TE 1 ms, flip angle 25FOV 250-400 mm, isotropic voxel -1.0 mm
Left Right
MRI acquisition Registration Visualization
MRA AcquisitionBolus Triggered 3D MRA (Care Bolus, SmartPrep, BolusTrak, Visual Prep)
✓ Good temporal and spatial resolution ✓ Focus region of interest without losing critical information✓ Gadolinium: 0.15 mmol/kg (0.3 ml/kg) @1.5 ml/sec✓ ✖ Breath hold✓ ✖ ECG gated
Parameter: TR 3.5 ms, TE 1.3 ms, flip angle 30FOV 250-400 mm, isotropic voxel -1.0 mm
Navigator gated 3D GRE sequence:
✓ High spatial but lower temporal resolution
✓ ECG (systole, diastole, or both) and respiration gated
✓ Useful for real time MRI guided procedures
✖Hard to separate right and left side
MRI acquisition Registration Visualization
MRA Acquisition
Isotropic voxels of 1.0 to 1.3 mm, TE 1.6 msec, TI 260 msec, and flip angle of 18 degrees. Whitehead KK, et al. J Cardiovasc Magn Resonan. 2014;16:P109.
CTA acquisition Registration Visualization
CTA AcquisitionCT Angiography with contrast
✓ Excellent temporal and spatial resolution ✓ Quick acquisition with minimal radiation*✓ Contrast: Isovue 300 ~ 2 ml/kg @ 3 ml/sec✓ Breath hold✓ ✖ ECG gated
Parameter: Slice thickness 0.5 mm, kVP 100, rotation time 0.35 s, pitch 0.813, CTDI 2.7 mGy
3D Rotational Angiogram
Rotational Angio Registration Visualization
✓ Excellent temporal and spatial resolution
✓ Quick acquisition with radiation exposure
✓ ContrastX Requires pacingX Different catheters required to
see multiple structures
Segmentation
CTA Segmentation
Smooth Hollow
CTA Segmentation
3DRA Reconstruction
Registration
2D / 3D Visual Matching RegistrationAP Lateral
MRI acquisition Registration Visualization
Registration – Internal Markers
MRI acquisition Registration Visualization
Registration – Internal Markers
CTA acquisition Registration Visualization
Ribs
Sternum
Spine
Registration – Internal Markers
Rotational Angio Registration Visualization
Surgical Clips
Sternal Wires
Tubes
Aligned
Registration – Internal Markers
MRI acquisition Registration Visualization
Valve Marker
LPA Stent
Registration – External Markers
MRI acquisition Registration Visualization
Vitamin E Capsule –Radiopaque Marker
Visualization
Fusion Visualization
Rotational Angio Registration Visualization
CMR Registration / Visualization
MRI acquisition Registration Visualization
CTA Registration / Visualization
CTA acquisition Registration Visualization
Registration / Visualization LimitationsMisaligned
Sternal Wires
Surgical Clip Sternal Wires
Tubes
Rotational Angio Registration Visualization
Case Utilization
HLHS status post GlennSevere TRResidual arch obstruction
Case Utilization
Le Bonheur Experience
Variable3DRA-Fusion
(n=25)
MR-Fusion
(n=25)
CT-Fusion
(n=25)P-Value
Radiation (min) 21.8 ± 12.2 18 ± 9.7 19.4 ± 10.4 0.04
# of angiography 7.2 ± 3.8 5.4 ± 4.7 6.8 ± 3.6 0.52
Dose-Area (cGy.cm2) 4101 ± 1382 2454 ± 1113 5607 ± 2465 0.01
Air Kerma (mGy) 654 ± 224 499 ± 189 806 ± 328 0.01
Contrast (mL/Kg) 4.9 ± 3.1 2.7 ± 2.4 5.9 ± 3.8 <0.001
Procedure (min) 214 ± 93 163 ± 38 167 ± 42 0.03
Anesthesia time (min) 258 ± 112 384 ± 174 213 ± 98 <0.001
Conclusions
MRI / CT acquisition
Registration to Fluoro
Visualization
References• Dori Y, Sarmiento M, Glatz AC, Gillespie MJ, Jones VM, Harris MA, Whitehead KK,
Fogel MA, Rome JJ. X-ray magnetic resonance fusion to internal markers and utility in congenital heart disease catheterization. Circ Cardiovasc Imaging. 2011;4:415-424.
• Glöckler M, Halbfaβ J, Koch A, Achenbach S, Dittrich S. Multimodality 3D-Roadmap for cardiovascular interventions in congenital heart disease – A single-center, retrospective analysis of 78 cases. Cathet Cardiov Interv. 2013;82:436-442.
• Goreczny S, Dryzek P, Moszura T. Novel 3-dimensional image fusion software for live guidance of percutaneous pulmonary valve implantation. Circ CardiovascInterv. 2016;9:e003711.
• Whitehead KK, Harris MA, McNeal GR, Fogel MA. Use of a 3D respiratory navigated IR-FLASH sequence after gadofosveset in the pediatric adult congenital population. J Cardiovasc Magn Resonan. 2014;16:P109.
Thank YouLe Bonheur Children’s
Hospital
Cardiac Catheterization TeamShyam Sathanandam, MDRush Waller, MDHitesh Agrawal, MD
Cardiovascular Magnetic Resonance Team
Anthony Merlocco, MDCara Morin, MD PhDRonak Naik, MDGovinda Paudel, MD
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