Dual Energy CT of the Heart: Perfusion and Beyond U. Joseph Schoepf, MD, FAHA, FSCBT MR, FSCCT Professor of Radiology, Medicine, and Pediatrics Director of Cardiovascular Imaging
Disclosures Consultant for / research support from Bayer Bracco General Electric Medrad Siemens
Integrative CHD Imaging with CT Primary morphological vs. functional evaluation of CAD (i.e. SPECT vs. ICA, CTA)? Early attempts at CT imaging Limited by experimental nature Limited by dedicated acquisition protocols Hybrid Imaging (e.g. SPECT and CT) Dual energy CT for myocardial perfusion defects Delayed enhancement dual energy CT Adenosine stress dual energy CT Quantitative, time resolved perfusion assessment
EBCT: Porcine Model of Myocardial Perfusion Perfusion CT: Animal Models Mohlenkamp, S. et al. Circulation 2000
Infarct Detection with CT CT for Myocardial Signs of CHD Nikolaou K. et al., Eur Radiol 2005
140kV 80 / 100kV Integrative Imaging: DECT
DECT for Myocardial Ischemia 74 yo woman with chest pain and abnormal SPECT 2x64x0.6mm, 80kV/140kV 0.33 s rotation time
Morphology and Function: DECT 74 yo woman with chest pain and abnormal SPECT Tight proximal stenosis D1 B. Ruzsics et al., Circulation 2008
Morphology and Function: DECT 74 yo woman with chest pain and abnormal SPECT B. Ruzsics et al., Circulation 2008
DECT Postprocessing F. Schwarz et al., Eur J Radiol 2008
DECT Radiation Dose 16 Slice CT DSCT DECT 12 ± 3.59 msv 9.8 ± 4.77 msv 4.54 ± 1.87 msv JM Kerl et al., Eur Radiol 2010
61 yo man, atypical chest pain Reversible Ischemia at Rest DECT
Vliegenthart et al., AJR in press DECT Can Detect Subtle Pathology
Ruszsics et al., RSNA 2009 Delayed Enhancement DECT
1 month 0 1 week Abnormal SPECT rest and/or stress Rest DECT Adenosine DECT Rest cemri (perfusion) Adenosine cemri (perfusion) Adenosine protocol: 140 µg/min/kg Delayed DECT (sequential) Delayed Enhancement (viability) B. Ruzsics et al., AHA 2008 Adenosine Stress DECT
Adenosine Stress DECT LM LAD D1 Reversible Ischemia
Adenosine Stress cmri Reversible Ischemia
Rest Stress Delayed Reversible Ischemia
Larger scan field of view (SFOV) for Dual Energy modes SFOV A/B detector: 50/33 cm 33 cm Next Generation DECT
Dual Energy with Selective Photon Shield Up to 80% improved separation of low and high energies Minimized spectral overlap Noise reduction Greater dose reserve Complete radiation dose neutrality compared with single energy CT number of quanta S 1 : 80 kv x 10 4 15 10 5 S 2 : 140 kv + SPS 80 kv 140 kv 140 kv + SPS 0.4 mm Sn 0 50 100 150 photon energy (kev) Next Generation DECT
75 msec Temporal Resolution in Dual Energy Mode 165 msec 75 msec DECT Temporal Resolution
Next Generation DECT
Quantitative DECT Perfusion Rest Stress
ECG triggered sequential shuttle mode, coverage 8 cm 4 cm 4 cm Dynamic Time Resolved Perfusion
Untitled-2 Stress Dynamic CT Perfusion Protocol G. Bastarrika et al., Invest Radiol 2010
140 µg/min/kg Adenosine Stress Dynamic Time Resolved Perfusion G. Bastarrika et al., J Cardiovasc Comput Tomography 2010
Absolute MBF Quantification MBF: 124ml/100 ml/min MBF: 60ml/100 ml/min
ccta Perfusion Viability Dynamic Time Resolved Perfusion G. Bastarrika et al., Invest Radiol 2010
50yo man w/ chest pain
Dynamic Time Resolved Perfusion
Monitoring Therapeutic Effects 95% RCA stenosis Stress Blood flow in defect: 65 cc/ 100 cc/ min Blood flow in healthy myocardium: 112 cc/ 100 cc/ min Rest Rotation time: 0.28 s Temporal resolution: 75 ms Tube voltage: 100 kv Prospectively triggered scans for 30 s Ho et al., Journal of Cardiovascular Computed Tomography, Vol 5, No 2, March/April 2011
Monitoring Therapeutic Effects Patent stent Stress Blood flow in former defect: 118 cc/ 100 cc/ min Blood flow in healthy myocardium: 112 cc/ 100 cc/ min Rest Ho et al., Journal of Cardiovascular Computed Tomography, Vol 5, No 2, March/April 2011 Rotation time: 0.28 s Temporal resolution: 75 ms Tube voltage: 100 kv Prospectively triggered scans for 30 s
Solving Clinical Dilemmas No stenosis Intermediate stenosis High grade stenosis Rule-out Rule-in Rule-out Dynamic Volumetric Stress MPI or DECT Stress/Rest MPI Discharge Discharge Cathlab Cathlab
F. Bamberg et al., Radiology 2011 Solving Clinical Dilemmas
Discriminator DECT Dynamic Perfusion Radiation dose +++ ++ Volume coverage +++ ++ Temporal resolution +++ +++ Ease of acquisition +++ ++ Ease of post processing ++ +++ Structural information +++ +++ Perfusion information ++ +++ Viability information +++ ++ Quantification ++ +++
Summary Future Perspectives Promising developments for CT imaging of myocardial perfusion and delayed enhancement CT not the primary method for evaluation of myocardial perfusion CTA is mainly aimed at imaging the coronaries CT a possibly attractive modality for integrative imaging of anatomy and perfusion Further refinements in technique (e.g. area detector CT, dual energy CT)
schoepf@musc.edu