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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
rodrigo.salgado@uza.berodrigo.salgado@uza.be
Cardiac CT was a popstar!
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
Acquiring the Data: CT
Steady increase in performance of CT
performance
CT: The Holy Grail
Spatial resolution
Temporal resolution
Speed of execution
Have we now everything that we desire?
New CT technology
New hardwareI HAVE A NEW TOY!
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
Dual Energy CT
• Dual x-ray energy spectrum
Specific materials attenuate differently from two X-ray spectra
Dual Energy CT
DECT can be performed with single- or double-source systems
Dual Energy CT
Latest technology uses one detector with two layers
Continuous dual energy acquisition in every scan
Dual Energy CT
DECT technology offers new applications
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
Clinical applications
• Thrombus or not?
Single contrast-phase detection of thrombus in LAA
Clinical applications
• Better SNR & CNR
Dual energy CT can lead to >50% CM savings due to better contrast
30 ml contrast medium
OK, this is boring!WHAT ELSE DO YOU HAVE?
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
New Kid in Town
Photon counting CT is coming!
• Photon-counting detectors (PCDs) X-ray photon -> electric signal (fast)
INDIRECT CONVERSION DIRECT CONVERSION
DETECTOR DETECTOR
SEPTUM
SEPTUM
SEPTUM - ---
--
- ---
- --
• Energy-Integrating Detectors (EIDs) X-ray photon -> light -> electric signal
(slow)
Detector comparison
Slide courtesy of R. Symons, MD
• 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
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
• 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??
• 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
Excellent CT-MR-histology correlation of scar
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
Photon-counting CT• Multi-Energy visualization of plaques
PC-CT can help in differentiating plaque materials
Software!THE POWER OF THE ROBOTS
Coronary CTA• One-pass CT subtraction
Subtraction of Calcium & stent material without additional acquisition
Coronary CTA• Arrhythmia & low-Dose CT
Cardiac CT is applicable to a larger population
0,19 mSV – 30 cc contrast medium144 BPM Atrial fibrillation
CT-FFR• Additional value over conventional angiography
CT-FFR requires excellent image quality
CT-FFR• Additional value over conventional angiography
CT-FFR still has some problems in the critical range
Combining CT Perfusion & FFR
Diagnostic performance may improve by CT perfusion & -FFR
From little to big data
Comparison with large datasetsComparison with large datasetsComparison with large datasets
MorphologyMorphologyMorphology FunctionFunctionFunction
Machine learning (ML)• Automatic Ca-score determination
ML can help in automated Ca-score from CT-A & non-gated scans
CT-FFR has potential to improve FFR algorithms
Machine learning (ML)
• ML in patients with suspected coronary artery disease
Adding Machine Learning for better mortality prediction than other scores
Machine learning (ML)
Integration of automated AI results in clinical reporting
Machine learning (ML)
Final ThoughtsA PRACTICAL POINT OF VIEW
CT detector technology is evolving
New technologies induce new applications
Excellent image quality is nevertgheless required
A radiologist with AI is probably better than one without
Thank you!