Cardiac applications of 16 slice MDCT

:Initial experience

Samsung Medical CenterDong-Joon Ahn

Purpose

• Applications of 16 slice MDCT

in cardiac disease

• To evaluate the effectiveness :

CAC , CTA , Functional analysis

Materials & Equipments

• 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.)

• CAC : 8 , CTA : 28

Method

– No contrast material

– 2.5mm x 8i scan (cine mode)

– Gantry rotation time : 0.5sec

– Prospective ECG gating : 75%

Calcium scoring

II. Evaluation

I. Image acquisition

– Agatstone score

Coronary arteries angiography

– 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

Method

I. Image acquisition

II. Evaluation

– Compare 45%, 55% & 75% of RR interval

Reconstruction method & heart rate

H R Acquisition

Mode

Temporal

Resolution

40~60 Snapshot

Segment

250ms, 1cycle

60~75 Snapshot Burst 125ms, 2cycles

75~90 Snapshot Burst

Plus

65ms, 4cycles

Reconstruction method

Snapshot segment mode

Snapshot burst mode

Snapshot burst plus mode

Post processing methods

• Volume rendering

• Maximum intensity projection (MIP)

• Reformation in cardiac short and long axis

• Vessel analysis

• Endoscopic view (fly-through)

• Curved reformation

Method

Results

Agatscore

0 in 4 14 in 1 55 in 1 821 in 1 928 in 1

I. Calcium scoring

• 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%)

II.Coronary arteries angiographyResults

LAD: 75% = Best

45%

55%

75%

Phase location and image quality

45% 55%

75%65%

Short and long axis of heart

Volume renderingCoronary vessel tree

view

LIMA - SVG Artifact

Automatic MIP MPVR

Curved reformation

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

– 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 (I)

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 EKG 동조화동조화

• Temporal resolution Temporal resolution 향상향상

• Isotropic resolutionIsotropic resolution영상획득영상획득

• SoftwareSoftware

Cardiac functionCardiac function

Short and long axis of heart

Before Before AfterAfter

Phase registrationPhase registration

Vessel Vessel analysisanalysis

Volume Volume renderingrendering

Isotropic resolutionIsotropic resolution영상획득영상획득

RCA Stent HR = 75-47-75RCA Stent HR = 75-47-75

Y- graft :RITA-LAD, Y- graft :RITA-LAD,

RITA-OM1-OM2-PLRITA-OM1-OM2-PL

45% volume rendering, HR: 45% volume rendering, HR: 75-8475-84