7/14/2015 1 Department of Biomedical Engineering Johns Hopkins University Advances in Cone-Beam CT and Emerging Applications: Extremities CBCT W Zbijewski The I-STAR Laboratory istar.jhu.edu Imaging for Surgery, Therapy, and Radiology JH Siewerdsen, JW Stayman, A Sisniega, G Gang, Q Cao, A Muhit, P DeJean, P Prakash Carestream Health J Yorkston, N Packard, R Senn, D Yang JHU Radiology JA Carrino, G Thawait, S Demehri, M Mahesh, A. Machado Funding Support Carestream Health NIH 2R01-CA-112163 NIH R21-AR-062293 NIH R01-EB-0188961 Fracture / Trauma →Monitoring of healing Insufficiency fractures Osteoporosis Dietary deficiencies Radiation therapy →Need for biomarkers Arthritis Osteoarthritis (OA) ~30 million US adults Joint replacement →Need for early biomarkers Rheumatoid arthritis ~1.5 million US adults Deformity and chronic pain Novel drugs →Monitoring of treatment response Gout ~8 million US adults →DE imaging Clinical Motivation Imaging capabilities: • Contrast resolution Joint space, tendons, ligaments • Spatial resolution Bone micoarchitecure • Bone composition (quantitative) • Weight-bearing (functional) • Longitudinal studies JHU Radiology JHU Radiology
12
Embed
Advances in Cone-Beam CT and Emerging Applications ...amos3.aapm.org/abstracts/pdf/99-27413-365478-110824.pdf · Advances in Cone-Beam CT and Emerging Applications: Extremities CBCT
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
7/14/2015
1
Department of Biomedical Engineering Johns Hopkins University
Advances in Cone-Beam CT
and Emerging Applications:
Extremities CBCT
W Zbijewski
The I-STAR Laboratory
istar.jhu.edu Imaging for Surgery, Therapy, and Radiology
JH Siewerdsen, JW Stayman,
A Sisniega, G Gang, Q Cao,
A Muhit, P DeJean, P Prakash
Carestream Health J Yorkston, N Packard, R Senn, D Yang
JHU Radiology JA Carrino, G Thawait, S Demehri,
M Mahesh, A. Machado
Funding Support
Carestream Health
NIH 2R01-CA-112163
NIH R21-AR-062293
NIH R01-EB-0188961
Fracture / Trauma →Monitoring of healing
Insufficiency fractures
Osteoporosis
Dietary deficiencies
Radiation therapy
→Need for biomarkers
Arthritis Osteoarthritis (OA)
~30 million US adults
Joint replacement
→Need for early biomarkers
Rheumatoid arthritis
~1.5 million US adults
Deformity and chronic pain
Novel drugs
→Monitoring of treatment response
Gout
~8 million US adults
→DE imaging
Clinical Motivation
Imaging capabilities: • Contrast resolution
Joint space, tendons, ligaments
• Spatial resolution
Bone micoarchitecure
• Bone composition (quantitative)
• Weight-bearing (functional)
• Longitudinal studies
JH
U R
ad
iolo
gy
JH
U R
ad
iolo
gy
50 100 150 200 250 300 350 400 450
50
100
150
200
250
300
350
400
450
500
7/14/2015
2
Contrast
resolution
Spatial
resolution
Quantitative Functional
(load-bearing)
Functional
(motion)
Rad First line imaging
+ +++ ++ +++ +
Fluoro Motion
+ ++ + ++ +++
CT Trauma
Fracture
++(+) ++ +++ + ++
MRI
Joint internal
derangement
+++ + ++ + ++
US
Soft-tissue lesions
Guidance
++ +++ + ++ +++
NM Infection
++ + +++ + +
(Dual Energy-CT)
MSK Radiology
MRI (www.GE.com)
MR – exquisite soft tissue
MR – limited spatial resolution
CT (www.GE.com)
CT – high-resolution bone
– limited soft tissue
System Configuration Flat-panel detector (FPD)
Compact gantry
Sitting / standing examination
Capabilities Weight-bearing scans
Natural stance
High isotropic spatial resolution
Multi-mode Rad / Fluoro / CBCT
Simplified logistics
Modest imaging dose
Longitudinal studies
*Zbijewski et al. Med Phys 2011 *Carrino et al. Radiology 2014
**Tuominen et al. AJR 2013 ** Huang et al. Skeletal Radiol 2015
A Dedicated Extremity CBCT Scanner
Planmed
Verity**
Carestream
+ JHU*
planmed.com
Sitting Configuration
General considerations Side entry – sliding door
Natural stance
FOV: 20 x 20 x 20 cm3
~20 sec/scan
X-ray source and FPD Fixed anode, 0.5 focal spot
50-125 kVp, 0.8 kW max
0.194 mm detector pixel
Clinical Prototype Patient studies:
Weight-bearing lower extremities
Arthritis and trauma
Application Development Joint space morphology
Bone health
Bone microarchitecture
Bone Mineral Density (BMD)
Standing Configuration
X-ray
Tube
FPD
Side Entry
Scanner Configuration
7/14/2015
3
Spatial Resolution
14
15
16
17 lp/cm
18
19
20
21
14
15
16
17 lp/cm
18
19
20
21
Cadaver Hand
Nominal Protocol (2x2 Binning) 0.388 mm pixels (0.26 mm voxels)
High-Res Protocol (1x1 Binning) 0.194 mm pixels (0.13 mm voxels)
Line-Pair Pattern High-Res Nominal
0 0.5 1 1.5 2 2.5 3
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
11
2x2
(Hann)
2x2
(Ramp)
1x1
(Ramp)
1x1
(Hann)
Frequency [lp/mm]
|MT
F|
Contrast Resolution
60 70 80 90 100 110 1200
0.5
1
1.5
2
2.5
3
kVp
SD
NR
Constant dose ~10 mGy
3 mGy
5.7 mGy
60 kVp
80 kVp
100 kVp
Cadaver knee
Adipose (-100 HU)
BR-1 (-45 HU)
Muscle (+10 HU)
Max Power ~0.875 kW
Dynamic Gain, 2X2 Binning (0.388 mm pixels)
0.52 mm isotropic voxels, Hann Filter
CBCT – MDCT comparison Bone and soft-tissue visualization tasks
CBCT: 1st generation prototype
MDCT: Siemens Definition
Observer study Fresh cadavers
10x knee, 10x hand
4 expert radiologists
8 diagnostic tasks
Preference and satisfaction
Diagnostic Imaging Performance
CBCT (10 mGy) MDCT (25 mGy)
Bone Recon
Ramp Filter
0.26 mm voxels isotropic
Bone Recon
‘Ultra-High-Res’
0.4 mm voxels isotropic
Soft Tissues
‘UHR Soft’ Protocol
0.6 mm voxels isotropic
Soft Tissues
Hann Fitler
0.52 mm voxels isotropic Demehri et al, Eur Radiol 2015
7/14/2015
4
Bone Tasks
Tissue Assessment Criteria Cortical
Bone
Visibility and integrity
Medullary
Bone
Architecture of trabeculae
Fracture
(if present)
Detection and
characterization
Soft Tissue Tasks
Tissue Assessment Criteria Tendon Uniform density
Integrity at attachment
Distinguish superficial from
deep
Muscle Architecture of muscle
Ligaments Integrity of ligaments
Fat Uniformity and visibility
Articular
Cartilage
Joint space width
CBCT (10 mGy) MDCT (25 mGy)
Bone Recon
Ramp Filter
0.26 mm voxels isotropic
Bone Recon
‘Ultra-High-Res’
0.4 mm voxels isotropic
Diagnostic Imaging Performance
Soft Tissues
‘UHR Soft’ Protocol
0.6 mm voxels isotropic
Soft Tissues
Hann Fitler
0.52 mm voxels isotropic
CBCT MDCT CBCT MDCT
p = 0.026 p = 0.353
* * * * 5
4
3
2
1
5
4
3
2
1
Bone Tasks Knee Hand
Excellent
Fair
Poor
Knee Hand
CBCT MDCT CBCT MDCT
p < 0.001 p < 0.001
*
*
*
* 5
4
3
2
1
5
4
3
2
1
Soft Tissue Tasks
Poor
Fair
Excellent
Observer study CBCT vs. MDCT and
radiography for fractures: Huang at el,
Skel Rad 2015 (Planmed Verity)
Week 9 Week 15
Bone Imaging: Fracture Healing JS
W c
han
ge in
OA
Thawait et al. RSNA 2013
Joint space width (JSW)
Bone image
Medial femoral condyle to tibial plateau
Joint Space Analysis in OA
Meniscal
protrusion
(MP)
4.65
mm
Soft-tissue image
Jo
int
Sp
ace W
idth
(JS
W)
(mm
)
Normal OA Normal OA
Non-Weight Bearing
(NWB)
Weight Bearing
(WB)
3.3
OA:
2.05
3.21
OA:
1.45
p < 0.001
Study setup
17 patients with OA of the knee
18 patients without OA
3 observers
Weight-bearing (WB) vs. Non-weight bearing (NWB):
Significant difference in JSW for OA
7/14/2015
5
Joint Space Analysis in OA
2.42
6.81
2.59
7.8
p = 0.001
4.65 mm
Soft-tissue image
Men
isca
l E
xtr
usio
n (
ME
) (m
m)
Normal OA Normal OA
Non-Weight Bearing
(NWB)
Weight Bearing
(WB)
Study setup
17 patients with OA of the knee
18 patients without OA
3 observers
Weight-bearing (WB) vs. Non-weight bearing (NWB):
Significant difference in JSW for OA
Significant difference in ME for OA
No significant difference in JSW or ME for non-OA
Meniscal Extrusion (ME)
WB vs. NWB hindfoot alignement: Hirschmann at el, Eur Rad 2014 (Planmed Verity)
𝚽 𝝏𝟏𝛀 = 𝐕𝟏
𝚽 𝝏𝟎𝛀 = 𝐕𝟎
𝑬 = −𝛁𝚽
𝛁 ⋅ 𝑬 =𝝆
𝝐𝟎 ⇒ 𝛁𝟐𝚽 𝒙 = 𝟎 ∀𝒙 ∈ 𝛀
𝚽 – Electric potential [V] 𝝆 – Charge density [𝐶 ⋅ 𝑚−3] 𝛀 – Joint space of interest
For an electric field 𝐸characterized by field lines l (𝑑𝑙 × 𝐸 = 0)
𝐽𝑆𝑊 𝑥0, 𝑦0, 𝑧0 = 𝑑𝑙 𝑠 𝑑𝑠𝑠1
𝑠0
𝑓𝑜𝑟 𝑎𝑙𝑙 𝑥0, 𝑦0, 𝑧0 ∈ 𝜕0Ω
𝛀 ⊂ ℝ𝟐, ℝ𝟑
The Electrostatic Model
Cao et al Phys Med Biol 2015
Joint Space Maps
Normal
Osteoarthritic A030 A038
A015
A041
A066
A067
A072
A073
A021
A023 A031 A043
M L A
P
Minimum JSW
Electrostatic Model JSM
Classification Accuracy
Radiologist
7/14/2015
6
Quantitative Imaging of Bone Health
Bone health Structure:
Micro-architecture (micro-CT)
Composition:
Bone Mineral Density BMD (DEXA / qCT)
Bone Marrow Edema BME (T2-weighted MRI)
(increased fluid content)
Risk of fracture
Mechanical competency (e.g. response to load)
Osteoporosis, arthritis, insufficiency fractures
CBCT: integrated platform for bone health assessment Superior bone visualization to conventional CT