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Les Outils Cliniques de Demain en Scanner Cardiaque · ECR 2018 –From Diagnosis to Prognosis...
Transcript of Les Outils Cliniques de Demain en Scanner Cardiaque · ECR 2018 –From Diagnosis to Prognosis...
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ECR 2018 – From Diagnosis to PrognosisECR 2018 – From Diagnosis to PrognosisThursday, March 1, 2018/08:30-10:00/Room N
Les Outils Cliniques de Demain en Scanner CardiaqueLes Outils Cliniques de Demain en Scanner Cardiaque Status en 2018Status en 2018
Rodrigo Salgado, MD, PhDRodrigo Salgado, MD, PhD
Dpt. Of Radiology | Antwerp University Hospital - Heilig Hart Lier | BelgiumDpt. Of Radiology | Antwerp University Hospital - Heilig Hart Lier | Belgium
[email protected]@uza.be
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Cardiac CT was a popstar!
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Myocardial perfusion CT4D evaluation of prosthetic heart valves
Movie courtesy of Ricardo Budde, MD - UMC Utrecht
Clinical applications are evolving as equipment improves
Evolving applications
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Acquiring the Data: CT
Steady increase in performance of CT
performance
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CT: The Holy Grail
Spatial resolution
Temporal resolution
Speed of execution
Have we now everything that we desire?
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New CT technology
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New hardwareI HAVE A NEW TOY!
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Single Energy CT
• Single x-ray energy spectrum• attenuation based on material density & composition
Attenuation characteristics are not necessarily unique to different materials
Ca+
IodineCT detector Photons
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Dual Energy CT
• Dual x-ray energy spectrum
Specific materials attenuate differently from two X-ray spectra
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Dual Energy CT
DECT can be performed with single- or double-source systems
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Dual Energy CT
Latest technology uses one detector with two layers
Continuous dual energy acquisition in every scan
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Dual Energy CT
DECT technology offers new applications
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Clinical applications
• Virtual unenhanced CT from CT-A acquisition
Dual energy CT can provide Ca-score from CT-A images
native CT-A Virtual unenhanced CT
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Clinical applications
• Thrombus or not?
Single contrast-phase detection of thrombus in LAA
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Clinical applications
• Better SNR & CNR
Dual energy CT can lead to >50% CM savings due to better contrast
30 ml contrast medium
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OK, this is boring!WHAT ELSE DO YOU HAVE?
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Dual X-ray source Fast kVp switching Dual-layer detector
• Relatively high overlap of the energy spectra
• Noise level may differ between low and high energy images
• 90° phase shift between low-and high-energy data
• Scattered radiation
• Relatively high overlap of the energy spectra
• Fixed thresholds
Dual Energy CT problems
Current dual energy CT systems have their disadvantages
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New Kid in Town
Photon counting CT is coming!
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• Photon-counting detectors (PCDs) X-ray photon -> electric signal (fast)
INDIRECT CONVERSION DIRECT CONVERSION
DETECTOR DETECTOR
SEPTUM
SEPTUM
SEPTUM - ---
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• Energy-Integrating Detectors (EIDs) X-ray photon -> light -> electric signal
(slow)
Detector comparison
Slide courtesy of R. Symons, MD
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• Energy-Integrating Detectors (EIDs)
Combine effects of energy and number of photons in intensity value
Loss of spectral information
• Photon-counting detectors (PCDs)
Measure number of photons (counts) and energies separately (faster integration time)
Photons divided into energy binsSpectral information retained
Detector comparisonSlide courtesy of R. Symons, MD
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Advantages over current technology
• Spectral information always available: no special protocol required• Less overlap between low and high energy data: better material separation• Energy thresholds can be adapted to clinical indication: more flexible• >2 energies possible: potential for multi-contrast imaging
Slide courtesy of R. Symons, MD
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• 3 wild mongrel dogs with chronic myocardial infarction• Late enhancement: Gadolinium• first pass Iodine
Gd injection I injection Imaging
10 min20 sec
By using different contrast media, can we differentiate them with one CT-acquisition??
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• 3 wild mongrel dogs with chronic myocardial infarction• Late enhancement Gadolinium, first pass Iodine
Multiphase CT acquired in a single acquisition!
Multi-energy cardiac imaging
First-pass enhancement of blood
late enhancement of subendocardial
Virtual unenhanced
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Excellent CT-MR-histology correlation of scar
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Spectral information
Noise propertiesSpatial resolution
Time
Pulse)Height
Intensity
E3
T ime
Pulse+Height
E2
E1
E4
E bin 1
E bin 2
E bin 3
E bin 4
PC-CT also provides better spatial resolution & noise properties
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Photon-counting CT• Multi-Energy visualization of plaques
PC-CT can help in differentiating plaque materials
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Software!THE POWER OF THE ROBOTS
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Coronary CTA• One-pass CT subtraction
Subtraction of Calcium & stent material without additional acquisition
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Coronary CTA• Arrhythmia & low-Dose CT
Cardiac CT is applicable to a larger population
0,19 mSV – 30 cc contrast medium144 BPM Atrial fibrillation
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CT-FFR• Additional value over conventional angiography
CT-FFR requires excellent image quality
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CT-FFR• Additional value over conventional angiography
CT-FFR still has some problems in the critical range
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Combining CT Perfusion & FFR
Diagnostic performance may improve by CT perfusion & -FFR
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From little to big data
Comparison with large datasetsComparison with large datasetsComparison with large datasets
MorphologyMorphologyMorphology FunctionFunctionFunction
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Machine learning (ML)• Automatic Ca-score determination
ML can help in automated Ca-score from CT-A & non-gated scans
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CT-FFR has potential to improve FFR algorithms
Machine learning (ML)
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• ML in patients with suspected coronary artery disease
Adding Machine Learning for better mortality prediction than other scores
Machine learning (ML)
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Integration of automated AI results in clinical reporting
Machine learning (ML)
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Final ThoughtsA PRACTICAL POINT OF VIEW
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CT detector technology is evolving
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New technologies induce new applications
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Excellent image quality is nevertgheless required
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A radiologist with AI is probably better than one without
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Thank you!