CT 最新技術的發展最新技術的發展最新技術的發展最新技術的發展

Copyright © Siemens AG 2010. All rights reserved.

西門子股份有限公司

醫療//業務發展經理

陳明達/Mainder Chen

謹致謹致謹致謹致::::

經濟部標準檢驗局經濟部標準檢驗局經濟部標準檢驗局經濟部標準檢驗局

感謝感謝感謝感謝

� Dr Lim// Tae Hwan Lim, MD, PhD�

Agenda

� CT 發展里程碑

� Image Acquisition time

� Temporal resolution

� Spatial resolution

� Radiation lower dose technique

� Functional Imaging

FIRST: Functional, Image acquisition time , Radiation dose, Spatial resolution, Temporal Resolution

Dual source

Flash

256 or 320 CT750 HD

New imaging technologies after 64 slices

1970Seq CT

CT發展

80‘s

Seq CTIncrease speed

90‘s

Spiral

2000‘sMulti slice

Increase slices

2s 1s0.75s

4 1664

HeadLung

Body Single Souce單源單源單源單源 CT

128256

320 512?

全球全球全球全球CT發展里程碑發展里程碑發展里程碑發展里程碑

1990Spiral CT

1998Multi slice CT

2005

Dual source

2007

4D spiral

Dual source 4D DSCT

Flash

1. Single or Dual source

2. Rows or slices

2008

2nd G dual source

Dual Source雙源雙源雙源雙源CT

Image Acquisition Time

� Detector width (64, 256, 320 …)

� Gantry rotation time/ 1, 0.8, 0.6, 0.5, 0.35, 0.33, 0.3, 0.28, 0.27

� Table feed speed

� Dual source technique

64 slice x 0.625 mm40 mm coverage

64 X 0.625 40 mm

6-9 secData from : Tae Hwan Lim, MD, PhD,

320 MDCTone beat//廣角鏡頭廣角鏡頭廣角鏡頭廣角鏡頭

64 MDCT7-8 heart beats

256 MDCT 3 heart beats

• Less step→→→→ Less chance for respiratory motion artifact→→→→ Less chance for heart beat variability→→→→ Less Chance for longer temporal resolution

Acquisition mode: prospective

Data from : Tae Hwan Lim, MD, PhD,

Husmann, Eur Heart J 2008 29:191-197

• No or minimal stair-step or banding artifact

- heart beat variability or respiratory motion

• Uniform contrast opacification

Impact of Faster Acquisition Time

Rybicki FJ, Int J Cardiovasc Imaging. 2008;24:535-46

<

Data from : Tae Hwan Lim, MD, PhD,

• High-pitch cardiothoracic CTA

� Dual source (Definition Flash)

- pitch as high as 3.4

� Perform triple rule-out exams

- < 1 second

- < 5 mSv

� No motion artifact

- small kids

- uncooperated patients

Impact of Faster Acquisition Time

Data from : Tae Hwan Lim, MD, PhD,

History of MDCT:multiplying the detector number

Data from : Tae Hwan Lim, MD, PhD,

Detector 的發展的發展的發展的發展

Detector Configuration

320 x

0.5mm16 cm16 cm

Aquilion 64

Z - Axis

Data from : Tae Hwan Lim, MD, PhD,

Temporal Resolution

廣角寬度= CT Detector wide 偵檢器寬度偵檢器寬度偵檢器寬度偵檢器寬度

快門時間= CT Temporal Resolution時間解析度時間解析度時間解析度時間解析度

專家說:拍動態影像，那快門一定要快喔 !!

快門的重要快門的重要快門的重要快門的重要

= 135 msrotation time 0.27 s

2Temp. Resolution =

達不到金標準的要求達不到金標準的要求達不到金標準的要求達不到金標準的要求,且心跳上限且心跳上限且心跳上限且心跳上限< 70 或更低或更低或更低或更低

目前所有單源CT的最佳快門(時間解析度)範圍135 ms and 175 ms, (廠家轉速都不同)

1 2

目前所有單源CT的補救方式,多段式影像重組計算

Coronary arteries change position =

limited image quality

(2 Segment Recon)

varies between = 67 - 200 msTemp. Resolution =

Source: Stephan Achenbach, M.D., University of Erlangen, Germany / Publication: Half-Scan vs. Multi-Segment Reconstruction for CT Coronary Angiography / December 2006

雙源CT的快門(時間解析度)=75 ms75 ms75 ms75 ms

= 75 msrotation time 0.28s

4Temp. Resolution =

心率無限制心率無限制心率無限制心率無限制,HR 40~140新的技術平台標準誕生了新的技術平台標準誕生了新的技術平台標準誕生了新的技術平台標準誕生了

Radiation Dose Exposure

Dose exposure

Effective Dose mSv (Mean)

GE 19 mSv, Philips 10 mSv, Siemens Single 9 mSv, Dual 11 mSv, Toshiba 15 mSv

Hausleiter et al JAMA Februar 2009

Slide:Courtesy of Dr. Hoffmann M

AMC

• Prospectively ECG-gated technique on 256

MDCT

Radiation Dose

Weigold WG, Int J Cardiovasc Imaging. 2009;25:217-230

n=200 Image quality: good to excellentRadiation exposure

�HR <65 bpm: one heart beat 5.7±±±±1.7 mSv in 151 (75%)

66-79 : two beats 13±±±±3.3 mSv>80 : three beats 19.5±±±±5.3 mSv

John Hoe, J Cardiovasc Comput Tomogr. 2009;3;257-261

First experience with 320First experience with 320--row MDCTrow MDCT

SOMATOM Definition Flash Lowest Dose: Sub-mSv heart

The Protection1 Study*Multi-center multi-vendor trial, 50 sites, 1965 coronary

CTAsMean radiation dose: 5.7 mSv – 36.5 mSv

*J. Hausleiter et al, JAMA 2009 Feb 4;301(5):500-7

Definition Flash:~ 1 mSv

70% of all Cardio scans performed with Flash Spiral

First scientific publications Low dose live counter

SOMATOM Definition Flash Scientific and routine proof

www.siemens.com/low-dose* for patients < 100 kg

Achenbach et al

Effective dose Ø 0.88 mSv*

Alkadhi et al

Effective dose Ø 0.90 mSv

Spatial Resolution

Limit for evaluation of in-stent restenosis

- Proximal vessel segment

- Larger diameter > 3.0 mm

- Strut thickness < 140 micro

- Instent restenosis > 35%

- Low and stable heart rate

- Absence of excessive image noise

Limitation -Stent

Data from : Tae Hwan Lim, MD, PhD,

Detector Slices Width SR

Definition 32x0.6 64* 1.9 cm 0.24 mm

Definition Flash 64x0.6 128* 3.8 cm 0.24 mm

Light speed VCT 64x0.625 64 4 cm 0.35 mm

CT750 HD 64x0.625 64 4 cm 0.23 mm †

Brilliance 64 64x0.625 64 4 cm 0.33 mm

iCT 128x0.625 256* 8 cm 0.33 mm

Aquilion 64 64x0.5 64 3.2 cm 0.35 mm

Aquilion One 320x0.5 320 16 cm 0.35 mm

Spatial Resolution (SR)

† Improved tube deflexion + New detector materialTemporal Resolution also very important

Data from : Tae Hwan Lim, MD, PhD,

Conventional Scan Technique for

Cardiac

Single Source scan technique

� Step and Shoot ( Prospective Triggering)� Need have stable low heart rate below 55

� low dose vs. Spiral scan

� No functional analysis

� Spiral (Retrospective Gating) � With functional analysis

� Dose higher than Step and Shoot mode

� Heart rate will be around 60~65 bpm

Single Source Step and shoot

MoveMove ScanScan Scan Scan Move

Robustness(Clinical challenges with arrhythmia and high heart rates. No functional imaging)

Dose Saving(High Dose savings due to sequential acquisition)++

-

Robustness(Arrhythmia)

Dose Saving

Single Source _Retrospective Gating/ECG Pulsing

++++

-

Siemens uniqueAdaptive ECG Pulsing

with SOMATOM SensationStandard ECG Pulsingwith Conventional CT

z-axis

低螺距

低速度前進

Detector

傳統心臟螺旋掃描技術

z-axis

低螺距低速度前進

不必要的數據

及過度的劑量

Reco

n

Detector z-coverage

Reco

n

傳統心臟螺旋掃描技術

New Scan Technique for Cardiac

Single Source scan technique

� Flash ( Prospective with Spiral scan)� < 65 bpm heart rate� <1 mSv� No functional analysis

� Step and Shoot ( Prospective Triggering)� < 85~90 bpm Heart rate � 1.5~5 msV� with or without functional analysis setting

� Spiral (Retrospective Gating) � Any heart rate � With functional analysis� 4~10 mSv

Siemens Flash

無須使用藥物無須使用藥物無須使用藥物無須使用藥物

快門快門快門快門(Single(Single(Single(Single----Segement):75 msSegement):75 msSegement):75 msSegement):75 ms

冠狀動脈掃描須服用藥物來降低心跳冠狀動脈掃描須服用藥物來降低心跳冠狀動脈掃描須服用藥物來降低心跳冠狀動脈掃描須服用藥物來降低心跳 ????

z-axis0.25s

螺距3.4

連續掃描

0.25秒

覆蓋整顆心臟

超低劑量

<1mSv

Flash Spiral 瞬間掃描，最低輻射劑量≦ 1mSv

Siemens Flash 的特殊性,三種掃描模式

Adaptive ECG Pulsing

FlashCardio Sequence

Flash Spiral Cardio

� 所有心率所有心率所有心率所有心率

� 功能性成像功能性成像功能性成像功能性成像

� 中中中中~~~~高高高高劑量劑量劑量劑量

� 中高心率中高心率中高心率中高心率

� 功能性成像功能性成像功能性成像功能性成像

� 低劑量低劑量低劑量低劑量

� 低心率低心率低心率低心率< 65bpm< 65bpm< 65bpm< 65bpm

� 超低劑量超低劑量超低劑量超低劑量1mSv1mSv1mSv1mSv

Adaptive Cardio Sequence

� 中中中中----高心率高心率高心率高心率

� 沒有功能性成像沒有功能性成像沒有功能性成像沒有功能性成像

� 中中中中----低劑量低劑量低劑量低劑量

5-7 mSv

2-5 mSv

<1 mSv

� Adaptive Dose Shield

backuponly

Cardiac Dose Approaches

2

4

6

8

10

12

14

16

18

20

SOMATOM Definition Flash

Flash Cardiao sequenceStep-and-Shoot

Spiral CTA

Bhatti, SCCT 2007 abstract 19

Dewey, Rofo, Jun 2007

Mori, EurJRad, Jul 2007

Hausleiter, JAMA, Feb 2009

Rybicki, J Card Im, Mar 2008

Earls, SCCT 2007, abstract 16

Cole, SCCT 2007 abstract 15

Sablayrolles, RSNA 2007, abstract

Stolzmann, Eur Radiol 2007

McCollough, Radiology 2007

Hausleiter, SCCT 2007 abstract 17

Scheffel, Heart 2008

Stolzmann, Radiology 2008

Dose(in mSv)

Flash Spiral Cardial

ECG Pulsing

Lower dose Technique

ECG Pulsing

ECG Pulsing

Courtesy of Friedrich-Alexander University Erlangen-Nuremberg – IMP / Erlangen, Germany

SOMATOM Definition Flash: 75 ms temporal resolution, 0.33 mm spatial resolution, 300 ms for 135 mm, 0.28 second rotation, 100 kV, 370 mAs / rotation

SOMATOM Definition FlashSub-mSv heart

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