Cardiac applications of
16 slice MDCT
:Initial experience
Samsung Medical Center
Dong-Joon Ahn
Purpose
• Applications of 16 slice MDCT
in cardiac disease
• To evaluate the effectiveness :
CAC , CTA , Functional analysis
Materials & Equipments
• CAC : 8 , CTA : 28
• Lightspeed ultra 16 (GE)
• Advantage workstation version 4.0 (GE)
• Millenia 3500 CT ECG monitoring system
(Invivo rsearch Inc.)
• Envision CT (Medrad)
• Iomeron 300 (Braco co.)
Method
Calcium scoring
I. Image acquisition
– No contrast material
– 2.5mm x 8i scan (cine mode)
– Gantry rotation time : 0.5sec
– Prospective ECG gating : 75%
II. Evaluation
– Agatstone score
Method
Coronary arteries angiography
I. Image acquisition
– Non-ionic CM 120 - 150ml, 4ml/s
– 0.625mm scan
– Gantry rotation time : 0.5sec
– Retrospective ECG gating
– Image reconstruction according to cardiac
phases : 5 - 95% of RR interval
II. Evaluation
– Compare 45%, 55% & 75% of RR interval
Reconstruction method & heart rate
HR
Acquisition Mode
Temporal
Resolution
40~60
Snapshot Segment
250ms, 1cycle
60~75
Snapshot Burst
125ms, 2cycles
75~90
Snapshot Burst
65ms, 4cycles
Plus
Reconstruction method
Snapshot segment mode
Snapshot burst mode
Snapshot burst plus mode
Method
Post processing methods
• Volume rendering
• Maximum intensity projection (MIP)
• Reformation in cardiac short and long axis
• Vessel analysis
• Endoscopic view (fly-through)
• Curved reformation
Results
I. Calcium scoring
Agatscore
0 in 4
14 in 1
55 in 1
821 in 1
928 in 1
Results
II.Coronary arteries angiography
• Best phase locations for image quality
– 45% : RCA in 7, distal LAD in 5
– 55% : RCA in 1
– 75% : LAD in most patients and RCA in 2
• good image quality in 33/36 (91%)
LAD: 75% = Best
45%
55%
75%
Phase location and image quality
45%
55%
65%
75%
Short and long axis of heart
Volume rendering
LIMA - SVG
Coronary vessel tree view
Artifact
Automatic MIP
Curved reformation
MPVR
Consideration
• Improved image reconstruction algorithm and
software
• Prospective or retrospective ECG gating
• Better temporal resolution
• Image acquisition of isotropic resolution
Limitations of coronary CTA
• Extensive calcifications
• Stents : spatial resolution
• Variable heart rate : poor image quality
• Radiation dose
• Small branches / septal branches
Conclusion (I)
– Screening asymptomatic high risk population
(CAC, CTA)
– Exclusion of stenosis in patients with low
likelihood of extensive disease
– Diagnosis in pts with atypical angina
– Post-procedural evaluation (CABG, stent)
– Plaque characterization
– Follow-up after drug treatment
Conclusion (II)
• The fast volume coverage of ECG gated 16
slice CT enables acquisition of the entire
heart volume with nearly isotropic resolution
within a single breath hold.
Hr 100-105
Cardiac CT
• EKG 동조화
• Temporal resolution 향상
• Isotropic resolution영상획득
• Software
Cardiac function
Short and long axis of heart
Phase registration
Before
After
Vessel analysis
Volume rendering
Isotropic resolution영상획
득
RCA Stent HR = 75-47-75
Y- graft :RITA-LAD,
RITA-OM1-OM2-PL
45% volume rendering, HR: 75-84