CT post processing and low dose scanning

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1 CT post processing and low dose scanning Gabor Szell GE Healthcare CT Modality Manager EE Annual Scientific and Educational Meeting Innovations in Cardiothoracic Imaging May 2011, Tokuda Hospital Sofia

2 What CT users ask for? To go further in diagnostic capabilities, we need higher resolution To push the limits of CT research, we need dynamic imaging & more than HU To further develop CT imaging we need to drastically reduce dose See more, know more, less dose Vascular 5% Thorax 12% Cardiac 1% 1% Interventional 1% Extremities Spine 4% Other 0% Virtual Colonoscopy 0% Abdomen 29% Pelvis 19% Brain/Head/Neck 28%

3 Looking for an optimal solution the best compromise Spatial resolution Fine-cell Detector + Visualization of fine structure - Image noise IQ Low dose Opti-Dose + 4D Modulation + Bowtie filters ++ Iterative reconstruction Temporal resolution EBCT Dual Source CT + Temporal resolution - Spatial resolution - Fast Dual energy Coverage Flat-Panel CT + Volume acquisition - Large angle Blurring, Dose

4 Looking for an optimal solution the best compromise Spatial resolution m coverage with new GEMSTONE detector fast response Low dose Temporal resolution ASiR iterative recon on raw data up to 35 fps Veo TM - the new CT breakthrough 0.5ms fast kv Dual Energy spectral imaging Coverage up to 31.5 cm dynamic & perfusion imaging

5 From conventional to Iterative Reconstructions FBP: - Fast - Make assumptions - Sensitive to noise - Amplifies artifacts Projection based IR

6 Adaptive Statistical Iterative Reconstruction - Models noise root causes (photon statistics, object noise) - As a result noise can be extracted during image reconstruction throughout several iterations - same noise level at 50% less dose

7 ASiR: 0.22 msv Coronary CT Angio 5 beats Snapshot pulse acquisition X-Ray Exposure: 1.7 s 80 kv & 90 mas DLP = mgy.cm (Eqv dose = 0.22 msv*) * Obtained by IRCP, using an adult chest factor of 0.014*DLP

8 ASiR: 0.86 msv Thorax 100 kvp & mas DLP = 51 mgy.cm (Eff Dose* = 0.86 msv) * Obtained by EUR EN, using an adult chest factor of 0.017*DLP

9 ASiR: 1,42 msv Colonoscopy Prone & supine acquisitions DLP = mgy.cm Eqv dose = 1.42 msv* * Obtained by EUR EN, using an adult abdomen-pelvis factor of 0.017*DLP

10 ASiR: 3 msv Abdomen / Pelvis DLP = 192 mgy.cm Effective dose = 3,2 msv* * Obtained by EUR EN, using an adult abdomen-pelvis factor of 0.017*DLP

11 Introducing Veo TM Model Based IR Raw data FBP Direct Reconstruction ASiR SYSTEM NOISE STATISTICS REAL 3D SYSTEM OPTICS Veo FBP with iterative image space correction Limited dose reduction opportunity Improved image quality** at lower dose SYSTEM NOISE STATISTICS Exceptional image quality at the lowest dose CPU required CPU required CPU required The diagram compares three reconstruction methods currently applied by GE Healthcare. **Image quality measured as image standard deviation.

12 Improving resolution & reducing blooming effect FBP Veo Images courtesy of J.L. Sablayrolles, M.D.

html Veo 100kV, 10mA, 0.4 rot 6.3DLP, 0.09mSv* 3.

13 Ultra low dose Chest follow-up 4mAs, 0.09mSv* FBP ASiR (50%) Typical CXR effective dose is about 0.06 msv. Source: Health Physics Society. Veo 100kV, 10mA, 0.4 rot 6.3DLP, 0.09mSv* 3.0mm 277mm * Obtained by EUR EN, using a chest factor of 0.014*D

14 450mm Ultra low dose Abdomen Pelvis 0.68mSv* FBP ASiR (50%) Veo 100kV, 35-44mA, 0.5 rot DLP 40, 0.68mSv* 0.625mm slice thickness * Obtained by EUR EN, using an abdomen factor of 0.015*DLP and a pe

Water Iodine Spectral Imaging Challenge: speed

FOV Raw data based processing Accuracy of

15 Water Iodine Spectral Imaging Challenge: speed and registration Single tube ultra-fast dual energy switching 0.5 ms switching between two energies Full 50 cm FOV Raw data based processing Accuracy of material separation Access to monochromatic images (spectral) Separate tissues to characterize

Spectral Imaging- Clinical benefits Quantitative CT characterize the chemical compositions such as kidney stones Characterize small lesions help characterize

16 Spectral Imaging- Clinical benefits Quantitative CT characterize the chemical compositions such as kidney stones Characterize small lesions help characterize enhancing vs nonenhancing lesions Optimize the contrast visualization with monochromatic imaging Reduce Metal and Beam Hardening Artifacts for clearer anatomical visualization

Quantitative Small Lesion Characterization Normalized Spectral HU Curves Clinical

characteristic via ROI s, like iodinated contrast for characterization of lesions

areas to help characterize enhancing lesions vs.

17 Quantitative Small Lesion Characterization Normalized Spectral HU Curves Clinical Value Spectral Curves aid physicians to graphically see the attenuation characteristic via ROI s, like iodinated contrast for characterization of lesions Normalized Spectral Curves allow clearer characterization Used in all anatomical areas to help characterize enhancing lesions vs. cysts or hemorrhagic lesions Quantify the material characteristics across all energy levels for a confident diagnosis Cases Courtesy of Dr. Hara

IV contrast administered, GSI MD Water clearly shows a very small kidney stone in the left kidney

18 Spectral Imaging Improved Visualization Left Kidney Stone Clinical Value Evaluate for kidney stones when IV contrast is utilized MD Water image described as a virtual non-contrast like With IV contrast administered, GSI MD Water clearly shows a very small kidney stone in the left kidney Monochromatic 70 kev Water (Virtual non-contrast) Images courtesy of Dr. Amy Hara, Mayo Clinic Arizona

Spectral Imaging Pulmonary embolism Spectral 70 kev Image Iodine

Curve Clinical value Thrombus in right pulmonary vein is depicted on

spectral HU curve confirms a low contrast enhancement in the lung

19 Spectral Imaging Pulmonary embolism Spectral 70 kev Image Iodine (Water) Color Map Iodine (Water) 70 kev w/roi Placements Spectral HU Curve Clinical value Thrombus in right pulmonary vein is depicted on 70 kev image MD Iodine images show clearly lung hypo perfusion resulting from the pulmonary emboli. This hypo perfusion is correlated with Nuclear medicine exam The spectral HU curve confirms a low contrast enhancement in the lung tissue surrounding the embolus. GSI allows physicians to evaluate lung perfusion defect resulting from pulmonary emboli

dramatically reduce metal artifacts Conventional

with MAR 75 kev with MAR 75 kev with MAR Metal /

clearly shows loss of bone around the femoral

interface (Blue arrows) The intact bone around

20 Metal Artifact Reduction Bilateral Hip Prosthetics Clinical value GSI with MARs can dramatically reduce metal artifacts Conventional 140 kvp image Conventional 140 kvp image 75 kev with MAR 75 kev with MAR 75 kev with MAR Metal / bone interface can be more easily appreciated GSI clearly shows loss of bone around the femoral prosthesis and soft tissue filling the metal-bone interface (Blue arrows) The intact bone around the lower part of the femoral prosthesis is also better seen (Red arrow)

21 Growing number of applications Neuro beam hardening correction Neuro clips Metal implants Lung perfusion Renal Stone characterization White/ grey matter differentiation CTA with implants Stent artefact reduction Lung nodules Virtual non-contrast imaging Brain hemorrhagecta calcium removal Endoleak assessmentlung vessels Gout

22 CT Advanced Technologies Spectral Imaging Iterative reconstruction Adaptive statistical IR Model Based IR Thank you!

23 Why spatial resolution is important in cardiac? 1. Calcium 2. Intracoronary stents 3. Moderate to severe stenosis 4. High heart rates, Arrhythmia 5. Bypass grafts - Native vessel heavily calcified 6. Dose Spatial resolution Spatial resolution Spatial resolution Temporal resolution Spatial resolution Image Noise /Dose

24 Highest Cardiac Spatial Resolution in the Industry 18.2 lp/cm Stent Follow-up Distal stents clearly visualized

Spectral Imaging Material Quantification Unusual example of quantifying renal calculi Renal

3 to 17.6 indicating Calcium Monohydrate.

Atlantic Medical Imaging Chemical Composition Chemical Name Composition Formula

25 Spectral Imaging Material Quantification Unusual example of quantifying renal calculi Renal stone passed by a 48 yo The stone was scanned using GSI GSI reports effective Z of 17.3 to 17.6 indicating Calcium Monohydrate. Lab analysis of the stone confirmed GSI finding Case and Data Courtesy of Dr Dowe at Atlantic Medical Imaging Chemical Composition Chemical Name Composition Formula Mineralogical Name Calcium Oxalate Monohydrate 80% CaC 2 O 4 H 2 O Whewellite Calcium Oxalate Dihydrate 10% CaC 2 O 4 2H 2 O Wheddellite Uric Acid 10% C 5 H 4 N 4 O 3 Urate

GE Healthcare. Revolution GSI. A Better Exam.

GE Healthcare. Revolution GSI. A Better Exam. GE Healthcare Revolution GSI A Better Exam. Put yourself instantly at the forefront of spectral CT. Revolution* GSI is a new generation of CT that delivers consistently high-definition imaging, for confident