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!