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

H R 40~60 60~75 75~90 Acquisition Mode Snapshot Segment Snapshot Burst Snapshot Burst Plus Temporal Resolution 250ms, 1cycle 125ms, 2cycles 65ms, 4cycles

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 Coronary 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

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