8/6/0 Diagnostic Image Quality Evaluation of an Extremity Cone-Beam CT Scanner: Pre-Clinical and First Clinical Results Abdullah Muhit Wojciech Zbijewski, J Webster Stayman John Yorkston, Nathan Packard, David Foos, Robert Senn, Dong Yang Gaurav Thawait, John Carrino Jeffrey Siewerdsen, Dept. of Biomedical Engineering, Johns Hopkins University Carestream Health Dept. of Radiology, Johns Hopkins University Cone-Beam CT for MSK Extremities Scope of Applications Orthopaedics Trauma (bone, joint, soft tissues) Arthroplasty (Implants) Osteoporosis Rheumatology OA, RA diagnosis and Tx response Sports Medicine Tendon, cartilage Peripheral vasculature Potential Capabilities Isotropic spatial resolution Potentially reduced dose Logistical factors - Space, workflow, cost Weight-bearing scans Multi-mode (Rad / Fluoro / CBCT) Dual-energy CBCT Complementary to MRI (and/or MDCT) MRI (www.ge.com) jeff.siewerdsen@jhu.edu
8/6/0 Cone-Beam CT for MSK Extremities 40 o Flat panel Detector X ray Tube SDD=55 cm X-ray source Side Entry Geometry SDD 55 cm SAD 4 cm Mag.. Up to 40 o rotation Imaging FOV xx cm Nominal scan time: 0 sec Flat-Panel Detector PaxScan 00+ FPD 0.94 mm pixels 0-0 fps Dynamic gain X-ray source Fixed anode (SRI Inc.) 0.5 mm focal spot 50-5 kvp 0. - 0 ma Max 0.875 kw Zbijewski et al. Med Phys 8(8) 0 Contrast Resolution Max ~0 ma Constant dose ~0 mgy Max Power ~0.875 kw 6 cm.5 mgy 5.7 mgy Adipose ( 00 HU) SDNR.5 BR ( 45 HU) 0.5 Muscle (+0 HU) 0 60 70 80 90 00 0 0 kvp Dynamic Gain, X Binning (0.88 mm pixels) 0.5 mm isotropic voxels, Hann Filter jeff.siewerdsen@jhu.edu
8/6/0 Contrast Resolution Adipose Insert 60 kvp 70 kvp 60 kvp 80 kvp 90 kvp 80 kvp 00 kvp 0 kvp 00 kvp Cadaver knee (Sagittal view) MTF Nominal Protocol (x Binning) 0.88 mm pixels (0.6 mm voxels) High-Res Protocol (x Binning) 0.94 mm pixels (0. mm voxels) 0.9 0.8 0.7 0.6 0.5 0.4 0. 0. 0. x (Hann) Spatial Resolution x (Ramp) x (Ramp) x (Hann) 0 0.5.5.5 Frequency [lp/mm] Line Pair Pattern Nominal 9 8 6 0 7 lp/cm 5 4 Cadaver Hand High Res 0 9 8 7 lp/cm 6 5 4 jeff.siewerdsen@jhu.edu
8/6/0 Pre-Clinical Assessment Fresh Cadaver Specimen 0 Cadavers 0 Cadavers Knees Hands with & without fracture MDCT Protocols (Siemens Definition) 0 kvp, 00 mas, 0.8 mm pitch Bone Recon Ultra High Res Protocol 0.4 mm voxels (isotropic) Soft Tissues UHR Soft Protocol 0.6 mm voxels (isotropic) CBCT Protocols 60 0 kvp (nominal 80 kvp) Bone Recon Ramp Filter 0.6 mm voxels (isotropic) Soft Tissues Hann Fitler 0.5 mm voxels (isotropic) ~5 mgy ~0 mgy 4 Expert Radiologists Pre-Clinical Assessment Soft Tissues Bone Tissues TaskTissue Assessment Criteria Tendon Uniform density Integrity at attachment Distinguish superficial from deep Muscle Architecture of muscle Ligaments Integrity of ligaments 4 Fat Uniformity and visibility 5 Articular Joint space width Cartilage 6 Cortical Visibility and integrity Bone 7 Medullary Architecture of Bone trabeculae 8 Fracture Detection and (if present) characterization jeff.siewerdsen@jhu.edu 4
8/6/0 Validation of Nominal CBCT Knee: Soft Tissues Preference Tests Side by side display Image = CBCT (kvp) vs Image = CBCT (kvp) Preference Score Normalized 0.8 0.6 04 0.4 0. Score PREFERENCE + Definite Preference for the Test image + Slight Preference for the Test image 0 No Preference Slight Preference for the Control limage Definite Preference for the Control image Preference Score Distribution 0 50 60 70 80 90 00 0 0 0 kvp * * * * * * * 0 60 70 80 90 00 0 0 kvp p = 0.00 0.00 0.87 0.77 0.0 0. Score Satisfaction 5 Excellent 4 Good Fair Poor Very Poor 5 4 Knee Diagnostic Satisfaction Bone Tasks Hand * * 5 * * 4 p = 0.06 p = 0.5 CBCT MDCT CBCT MDCT Knee Soft Tissue Tasks Hand Hand CBCT MDCT 5 * 5 * 4 * 4 * p < 0.00 p < 0.00 CBCT MDCT CBCT MDCT Knee jeff.siewerdsen@jhu.edu 5
8/6/0 Preference Tests CBCT MDCT CBCT MDCT Preference Definite Slight 0 No Pref. Preferen nce Scale * 0 * * Bone Tissues * CBCT MDCT Clinical Pilot Study Imaging Performance in Clinical Scenarios Knee Group Hand Group 0 participants Standing and/or Sitting 0 participants Repeat scans Tx response jeff.siewerdsen@jhu.edu 6
8/6/0 First Clinical Results Soft Tissues Fracture at 5 th Proximal Phalanx First Clinical Results Patient A00 STANDING (weight bearing) Knee Bone Recon Soft Tissue Recon jeff.siewerdsen@jhu.edu 7
8/6/0 First Clinical Results Sitting (Non weight bearing) Standing (Weight bearing) Comparison (Registered on Tibia) Sitting Standing Conclusions Previous Technical Assessment / Optimization 80 kvp [Dose ~0 mgy, less than MDCT (~5 mgy)] Bone Recon (0.6 mm voxels) Soft Tissue Recon (0.5 mm voxels) Supported by ini al qualita ve studies with expert observers Diagnostic Satisfaction EXCELLENT Cortical and medullary bone GOOD Soft tissues Comparison of CBCT and MDCT Bone Tasks: comparable or improved for CBCT Soft Tissue: comparable or improved for MDCT Significant room for improvement: Dose and spatial resolution Scatter correction, beam hardening correction Patient Pilot Study Underway (with promising initial results) Workflow, patient comfort Simple immobilization reducing motion Demonstrating new capabilities Weight bearing knee, Longitudinal monitoring jeff.siewerdsen@jhu.edu 8
8/6/0 Acknowledgements Collaborators K Means (Union Memorial Orthopaedics) C Johnson (JHU Orthopaedics) F Frassica (JHU Orthopaedics) S Mears (JHU Orthopaedics) L Schon (Union Memorial Orthopaedics) C Bingham (JHU Rheumatology) M Mahesh (JHU Radiology) Funding Support Carestream Health NIH R0-CA-6-0 jeff.siewerdsen@jhu.edu 9