This study investigated using spectral detector CT (SDCT) to perform dynamic myocardial CT perfusion (CTP) in a porcine model. SDCT allows simultaneous acquisition of low and high energy projection data, enabling synthesis of monoenergetic images without beam hardening artifacts. A porcine model was used with adjustable coronary occlusion guided by fractional flow reserve measurements under different hemodynamic conditions. 70keV monoenergetic images had significantly reduced beam hardening artifacts and allowed more accurate myocardial blood flow quantification compared to conventional 120kV images. The study demonstrated the potential of SDCT to provide robust cardiac CTP for assessing both coronary anatomy and myocardial ischemia.
CASE: 58 year old male presented with a liver lesion seen on prior imaging. A dual energy scan was performed to further characterize the lesion. Volumetric Dual Energy scans were performed following the injection of 80mls of contrast. Scans were performed during Arterial Phase, early Portal Phase and Delayed at 3mins. Monochromatic images, iodine maps and virtual non contrast images were generated for review.
Application of dect in emergency radiology including the application in diagnosis of renal calculi, bone marrow edema, gout , abdominopelvic imaging,detection of pulmonary embolism and in cardiac imaging.
Review of current applications of spectral CT from head to toe. Contact info: Garry Choy MD MSc, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
Dual energy CT in radiotherapy: Current applications and future outlookWookjin Choi
Dual energy CT in radiotherapy: Current applications and future outlook
Wouter van Elmpt, Guillaume Landry, Marco Das, Frank Verhaegen
Department of Radiation Oncology (MAASTRO), GROW – School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany; Department of Radiology, GROW – School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands; and Medical Physics Unit, Department of Oncology, McGill University, Montréal, Canada
CT (Computed Tomography) scan is a modern imaging technique. It has undergone a lot of developments in the past decade.These developments are mostly focused to reduce the adverse effects of CT scan as much as possible. Moreover, there are many ongoing kinds of research on the post-processing of the reconstructed image, filtering of noise in image reconstruction, reducing radiation exposure etc.The recent advancements in CT scan technology are as follows:-
Higher Slice Systems
New Detector Technology
Iterative Reconstruction
Spectral CT Imaging
Artificial Intelligence
Low Dose CT
A brief description of them is given on the slide.
CASE: 58 year old male presented with a liver lesion seen on prior imaging. A dual energy scan was performed to further characterize the lesion. Volumetric Dual Energy scans were performed following the injection of 80mls of contrast. Scans were performed during Arterial Phase, early Portal Phase and Delayed at 3mins. Monochromatic images, iodine maps and virtual non contrast images were generated for review.
Application of dect in emergency radiology including the application in diagnosis of renal calculi, bone marrow edema, gout , abdominopelvic imaging,detection of pulmonary embolism and in cardiac imaging.
Review of current applications of spectral CT from head to toe. Contact info: Garry Choy MD MSc, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
Dual energy CT in radiotherapy: Current applications and future outlookWookjin Choi
Dual energy CT in radiotherapy: Current applications and future outlook
Wouter van Elmpt, Guillaume Landry, Marco Das, Frank Verhaegen
Department of Radiation Oncology (MAASTRO), GROW – School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands; Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany; Department of Radiology, GROW – School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands; and Medical Physics Unit, Department of Oncology, McGill University, Montréal, Canada
CT (Computed Tomography) scan is a modern imaging technique. It has undergone a lot of developments in the past decade.These developments are mostly focused to reduce the adverse effects of CT scan as much as possible. Moreover, there are many ongoing kinds of research on the post-processing of the reconstructed image, filtering of noise in image reconstruction, reducing radiation exposure etc.The recent advancements in CT scan technology are as follows:-
Higher Slice Systems
New Detector Technology
Iterative Reconstruction
Spectral CT Imaging
Artificial Intelligence
Low Dose CT
A brief description of them is given on the slide.
MDCT Principles and Applications- Avinesh ShresthaAvinesh Shrestha
Multidetector CT (MDCT) is one of the most commonly used imaging modality in the field of Radiology. Development and advancement in MDCT has made it's application as a major component in diagnosis and treatment planning of multitude of disease across the planet. This presentation briefly describes its basic principle and it's wide variety of application in medical imaging.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
CT is one of the highest contributor for medical radiation exposure to patients. Some common CT dose descriptors and dose optimizations methods are briefly described in this presentation.
Image Quality, Artifacts and it's Remedies in CT-Avinesh ShresthaAvinesh Shrestha
CT is one of the frequently used diagnostic imaging modalities in Radiology. Knowledge about image quality and artifacts is essential when diagnosing a patient with the help of CT images. Moreover, Radiology Technologist's should be very well aware about the ways to identify and eliminate or minimize the artifacts in CT for better image quality.
Dual energy imaging and digital tomosynthesis: Innovative X-ray based imaging...Carestream
Dual-energy (DE) imaging and digital tomosynthesis (DT) have been around for a few decades, but recent advancements in digital detectors have made this technology increasingly promising in clinical use. For more information about Carestream's imaging portfolio, visit www.carestream.com/medical or http://www.carestream.com/blog/2016/03/15/dual-energy-imaging-and-digital-tomosynthesis/
Explain the non safe or harm aspects of CT scan on the patient,, particularly after multiple CT scans done for one patient. mentioned essentially the risk of cancer in later life, which reach 1/2000.
Also, mentioned the organs, age group, and gender which affected more by CT radiation
Finally , stressing on eliminating CT scan as possible
Computed tomography (CT scan) is a medical imaging procedure that uses computer-processed X-rays to produce tomographic images or 'slices' of specific areas of the body. These cross-sectional images are used for diagnostic and therapeutic purposes in various medical disciplines.
GE Healthcare Revolution ACT EX Clinical Image GalleryGaurav Shah
Designed with your needs in mind, Revolution ACTs helps you improve standards of patient care by providing new levels of image quality. Intelligent technology designed to help you acquire high-quality images using lower doses of radiation, contributing to more accurate diagnoses and lower exposures for patients.
MDCT Principles and Applications- Avinesh ShresthaAvinesh Shrestha
Multidetector CT (MDCT) is one of the most commonly used imaging modality in the field of Radiology. Development and advancement in MDCT has made it's application as a major component in diagnosis and treatment planning of multitude of disease across the planet. This presentation briefly describes its basic principle and it's wide variety of application in medical imaging.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
CT is one of the highest contributor for medical radiation exposure to patients. Some common CT dose descriptors and dose optimizations methods are briefly described in this presentation.
Image Quality, Artifacts and it's Remedies in CT-Avinesh ShresthaAvinesh Shrestha
CT is one of the frequently used diagnostic imaging modalities in Radiology. Knowledge about image quality and artifacts is essential when diagnosing a patient with the help of CT images. Moreover, Radiology Technologist's should be very well aware about the ways to identify and eliminate or minimize the artifacts in CT for better image quality.
Dual energy imaging and digital tomosynthesis: Innovative X-ray based imaging...Carestream
Dual-energy (DE) imaging and digital tomosynthesis (DT) have been around for a few decades, but recent advancements in digital detectors have made this technology increasingly promising in clinical use. For more information about Carestream's imaging portfolio, visit www.carestream.com/medical or http://www.carestream.com/blog/2016/03/15/dual-energy-imaging-and-digital-tomosynthesis/
Explain the non safe or harm aspects of CT scan on the patient,, particularly after multiple CT scans done for one patient. mentioned essentially the risk of cancer in later life, which reach 1/2000.
Also, mentioned the organs, age group, and gender which affected more by CT radiation
Finally , stressing on eliminating CT scan as possible
Computed tomography (CT scan) is a medical imaging procedure that uses computer-processed X-rays to produce tomographic images or 'slices' of specific areas of the body. These cross-sectional images are used for diagnostic and therapeutic purposes in various medical disciplines.
GE Healthcare Revolution ACT EX Clinical Image GalleryGaurav Shah
Designed with your needs in mind, Revolution ACTs helps you improve standards of patient care by providing new levels of image quality. Intelligent technology designed to help you acquire high-quality images using lower doses of radiation, contributing to more accurate diagnoses and lower exposures for patients.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Recent advances in imaging techniques/ /certified fixed orthodontic courses b...Indian dental academy
Welcome to Indian Dental Academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy has a unique training program & curriculum that provides students with exceptional clinical skills and enabling them to return to their office with high level confidence and start treating patients
State of the art comprehensive training-Faculty of world wide repute &Very affordable
Baby Car Seat 1Roughly above 60% of baby car seat types become established incorrectly. A typical blunder includes upgrading a baby seat sooner than necessary. This article discusses some basic tips to help reduce errors.
Engineered Wood Flooring UK - Hardwood and Oak FlooringSource Wood Floors
Engineered wood flooring is popular nowadays because of its unmatched strength and durability. At source wood floors you can buy wide range of engineered wood flooring products with unbeatable prices and quality. In this document we have represent some of our most demanding engineered flooring products view now.
Automated quantitative assessment of left ventricular functions by MR image s...An-Cheng Chang
Thesis (English):
http://handle.ncl.edu.tw/11296/ndltd/08095156356149825986
General Information:
This is the slides for my MSc thesis defense, which introduces an algorithm that automatically analyzes cardiac magnetic resonance scans for extracting left ventricular cardiac parameters. These parameters are crucial for determining whether or not a patient suffers from certain forms of cardiovascular diseases, such as ischaemic heart disease and hypertrophy.
The performance of the algorithm in terms of segmentation accuracy (APD) outperforms all other similar reported algorithms (as of 2014) that also use the same CMR scan database* by at least 15%. This means more accurate cardiac parameters can be obtained using my proposed algorithm.
*Evaluation is done using the Cardiac MR Database provided by Sunnybrook Health Science Center, Toronto, Canada.
this presentation targets radio-diagnosis, neurology and neurosurgery junior staff, it presents simple basics of CT perfusion including principle, technique, applications, interpretation with few quiz cases.
Perfusion MRI (DSC and DCE perfusion techniques) for radiology residents
SPIE_2015_Fahmi
1. Dynamic Myocardial Perfusion in a
Porcine Balloon-induced Ischemia Model
using Spectral Detector CT
Rachid Fahmi 1, Ph.D.,
Brendan Eck1, Jacob Levi1, Anas Fares2, Mani Vembar3, Amar Dhanantwari3,
Hiram Bezerra2, and David Wilson1,4
1 Biomedical Imaging Laboratory, Case Western Reserve University
2 Harrington Heart and Vascular Institute, University Hospitals, Case Medical Center
3 Philips Healthcare
4 Radiology, Case Western Reserve University
rxf143@case.edu
2. Investigate the performance of dual energy CT (DECT) with a prototype
spectral detector CT (SDCT) scanner (Philips Healthcare) to perform
dynamic myocardial CT perfusion (CTP) on a percutaneous porcine
model with adjustable coronary occlusion guided by fractional flow
reserve (FFR) measurements.
Objective
Adding robust cardiac CTP to coronary CTA will make CT a one stop
shop imaging modality for cardiac imaging.
Clinical Relevance
Clinical use of CTP remains limited to date due in part to x-ray dose, BH
artifacts, and partial scan artifacts.
Current Challenges
3. Context and motivation
How can we address some CTP challenges?
• DECT has the potential of producing images free of beam hardening artifacts
by synthesizing mono-energetic (monoE) images.
• Dynamic CTP requires faster scanners to avoid partial scan artifacts.
• Coronary CTA is the only non-invasive imaging method capable of detecting
coronary stenoses.
• Significant discordance between angiographic stenosis (anatomy) and
myocardial ischemia (function).
• Over 60% of invasive coronary angiographies (ICA) are negative, subjecting
patients to unnecessary discomfort/risk, and driving up costs.
• No existing non-invasive test to assess both anatomic and functional
ischemia in a single setting.
• Current guidelines recommend documenting ischemia with a non-invasive
functional test (s.a., SPECT, MR).
• CT may be the perfect gatekeeper exam giving both anatomy (CTA) and
function (CTP), a one-stop-shop for value-based reimbursement.
4. DECT Technologies
“Dual Source”
Two x-ray spectra (e.g.,
80kV and 140kV)
“Single source with dual
kV” in single rotation (e.g.,
80kV and 140kV)
“Spectral Detector System”
One x-ray source and two
energy-resolving detectors
… Single source and kV switching between sequential gantry rotations.
… Or photon counting detector
5. • Simultaneous detection of low and high x-ray photon energies:
Low and high projection data are perfectly registered, spatially
and temporally, with each other.
Ideal for imaging moving objects such as a beating heart.
• Allows for projection space reconstruction and processes
Accurate material decomposition and BH correction.
• Fast gantry rotation (0.27s)
Allows full 360degree acquisitions
No shading artifacts in dynamic acquisitions.
• Full field of view (FOV) acquisitions (50cm).
• No cross scatter .
Some advantages of the SDCT system
6. Generation of monoE images
( ) ( ) ( )1 2
1 2
, ( ) ( )r E r E r E
µ µ
µ ρ ρ
ρ ρ
= +
Two basis material
sinograms
Two basis material
density maps
70keV50keV 120keV
Synthesized
monoE images
7. Cylindrical acrylic phantom:
diameter: 26 cm
thickness: 6cm
8 inserts
Measured iodine
concentrations (IC) from
iodine equivalent-density
image versus real IC used in
the phantom.
Phantom Experiment
y = 1.0586x + 0.1298
R² = 0.9999
0
2
4
6
8
10
12
0 2 4 6 8 10 12
Measured[mgI/mL]
Real [mgI/mL]
Accuracy of material decomposition
9. -40
-20
0
20
40
60 70 80 90 100 110 120 120kVp
BHA(HU)
keV
conventional monoE
Optimal keV?
70keV is chosen as
the optimal keV to
quantify blood flow
at high iodine CNR
and low noise level.
10. Cardiac CTP Experiments: porcine model
Animal preparation in surgical suite:
placement of FFR wire, balloon, and
microsphere injections
Acquisition of CTP scans for different
hemodynamic conditions guided by FFR
Fluorescent image of microsphere
deposition in myocardium used for
ground truth flow quantification
FFR readings to achieve
a targeted ischemia level
Preparation of heart for
freezing and Cryo-imaging
• First myocardial CT perfusion using the SDCT scanner.
11. Imaging Protocol
11
• Prospective ECG-triggered scans at end systole (45% R-R).
• Tube Voltage: 120kVp; Tube Current: 100mAs.
• Full 360 degree scan coverage.
• Omnipaque 350 followed by saline flush (20 mL @ 5 mL/sec).
• Initiate scan 3-4sec post injection, and acquire every heart beat a total of
30-35 volumetric scans (< 25sec) with respirator off.
• Scan under different hemodynamic conditions, with >15min between
consecutive scans.
• Conventional and monoE reconstructions of 2mm thick slices with no overlap.
• Motion correction using a cubic B-spline deformable registration model.
• Average CT map generation from registered scans.
• Semi-automatic segmentation of LV myocardium using averaged CT volume.
• Propagate segmentation results to entire 4D sequence.
• Model-independent deconvolution method based on bSVD with Tikhonov
regularization to quantify myocardial blood flow (MBF).
Recons and Preprocessing
12. tissue artC (t) F.C (t) R(t)= ⊗
• Arterial input function and tissue time-attenuation curve are related by
Quantification of Myocardial Blood Flow
• Ill-posed problem due to noise Regularize using Tikhonov method
2 22
2 2x
x argmin( x x )A b Lλ= − +
2
2 2
1
.b
x ( ). .
Tn
i i
i
i i i
u
vλ
σ
σ λ σ=
=
+
∑
• Solve for flow-scaled IRF, x=F.R(t), using bSVD decomposition of
1
1
.
x ( . . ). ( ).
Tn
T i
i
i i
b
V U b
σ
−
=
=Σ =∑
u
v
2
2x
x argmin( x )lsq A b= −
. .VT
A U= Σ
• Discretize and transform into an algebraic form
.xA b= 1. (t ) 0 ,
0 .
a i j
ij
t C for j i
a
for j i
− −∆ ≤ <
=
≥
( ),i tissue ib C t=with and
13. log xA b−
optλ
Less filtering
More filtering
log Lx
How to pick ?λ
• L-curve criterion (LCC): log-log plot of for a range of values( Lx , x )A bλ λ − λ
• Fit a smooth spline to obtained data points.
• Optimal corresponds to location on fitted spline with max curvature.λ
• If too small: noisy solution.
• If too large: poor approximation to real solution.
λ
λ
14. • Due to high iodine concentration in aorta and heart chambers and to the polychromatic
x-ray beam, some BH artifacts appear as hypo-enhanced areas on myocardium.
• These artifacts may be construed as perfusion defects. If uncorrected they lead to
inaccurate perfusion quantification.
• BH artifacts are significantly reduced on the projection-based 70keV images.
Beam hardening (BH) artifacts
Successive slices corresponding to a baseline scan (FFR=1).
W/L:150/60
Conventional
120kV
monoE
70keV
15. Baseline scan: no inflation
• Baseline scan with balloon deflated.
• Deconvolution of distorted arterial and
myocardial TACs leads to inaccurate MBF
measurments.
Effects of BH on TACs
and quantified MBF
120kV 70keV
120kV 70keV
• 15% flow reduction in BH-affected
myocardial regions in 120kV data vs. 70keV.
• BH effects distort tissue TACs in 120kV
images.
• BH effects on myocardial TACs are
significantly reduced for 70keV.
16. 0
20
40
60
80
100
120
Antero-septal Inferior Lateral Anterior
MBF(ml/min/100g)
Myocardial wall
120 kVp
0
20
40
60
80
100
120
Antero-septal Inferior Lateral Anterior
MBF(ml/min/100g)
Myocardial wall
70 keV
• Baseline scan with balloon completely deflated.
• Reduced BH artifacts in 70keV lead to more
uniform MBF throughout the non-ischemic
myocardium compared to 120kV-based MBF.
BH effects MBF (Cont’d)
17. • Detection of ischemia in correct LAD territory (FFR~0.35).
• Consistency of MBF quantification across several consecutive slices.
• BH artifacts lead to inaccurate perfusion measurements for conventional 120kV data:
BH lead to underestimation of mean MBF in anterior and inferior walls (yellow arrows).
BH and higher noise lead to overestimation of mean flow in mid-septal and infero-lateral walls(red arrows).
MonoE 70keV
Conventional 120kV
Slice2 Slice8Slice6Slice4 ml/min/100g
Ischemic case
Slice2 Slice8Slice6Slice4
18. ischemic
ratio
normal
mbf
F
mbf
=
Validation of MBF quantification
• Use relative flow as ratio of mean ischemic to mean normal flow and compare against
wire FFR for different hemodynamic conditions:
*
**
***
p=0.001 from 70keV
p=0.002 from 70keV
p=0.08 from 70keV*
***
**
• Compute and average over 15 adjacent slices and compare results to pressure
FFR target for normal and two ischemic conditions.
ratioF
19. Summary
• We reported the first dynamic CT perfusion findings using a novel
percutaneous porcine model and Philips’s SDCT scanner.
• Simultaneous acquisitions of LE & HE data permits synthesis of projection-
based monoE images relatively free of BH artifacts.
• A phantom experiment designed to analyze sensitivity of iodine detection for
monoE images vs. conventional single energy CT.
• 70keV chosen as the optimal energy for myocardial CTP assessment.
• Designed a comprehensive processing tools for quantitative myocardial CTP.
• Compared to conventional SECT, 70keV-based flow less affected by BH and
corresponding relative flow correlates better with pressure FFR values.
• Ongoing work:
• Additional animal studies.
• CTP validation against microspheres-based measurements.
20. Acknowledgments
Biomedical Imaging Lab
Hao Wu
Radiology
Scott Esposito
Philips Healthcare
Tsvi Katchalski, PhD (Haifa, Israel)
Steve Utrup (Cleveland, OH)
Funding
Ohio Third Frontier research grant from the state of Ohio
to CWRU, Univ. Hospitals and Philips Healthcare, OH.
Surgery
Steve Schomisch, PhD
Cassandra Cipriano
Cardiovascular CORE Lab
Xiaorong Zhou, MD
Kashif Shaikh, MD