Table of Contents

1. Overview

2. Introduction

Importance of Heart Rate Control

Importance of Nitrates

Selection of Tube Current and Potential

3. Siemens SOMATOM Definition Flash, SOMATOM Drive and SOMATOM Force

Topogram

CaSc (optional) - Non-contrast Examination

Test Bolus

Alternatively, CARE Bolus

Prospective Adaptive Triggered Sequential Coronary CT Angiography

(Heart Rates: up to 80 bpm)

Alternatively, Flash/ Turbo Flash Cardio

(Heart Rates: Below 62 bpm (Flash/Drive), below 66 bpm (Force), stable HR)

Contrast Protocol

4. Siemens SOMATOM Definition AS+ & Edge

Topogram

CaSc (optional) - non-contrast examination

Test Bolus

Alternatively, CARE Bolus

Prospective adaptive triggered sequential coronary CT Angiography

(Heart Rates: up to 70 bpm)

Contrast Protocol

5. Siemens SOMATOM go.Top

Topogram

CaSc (optional) - non-contrast examination

Test Bolus

Alternatively, CARE Bolus

Coronary CT Angiography (Heart Rates: up to 70 bpm)

Contrast Protocol

6. Bibliography

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1. Overview

Coronary computed tomography angiography (CCTA) is a non-invasive diagnostic for detecting coronary

artery disease (CAD). CCTA is increasingly utilized in clinical practice for evaluating coronary anatomy for

obstructive disease and plaque.

It is, however, imperative that artifact free CCTA image data is obtained in order for it to be successfully

analysed for anatomic assessment and/or to act as adequate input for adjunct analyses such as physiologic

simulations. Data acquisition strategies and scanning protocols may vary depending on scanner manufacturer,

system, and institutional preferences. This document provides references for reliable image acquisition

for CCTA.

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2. Introduction

Image acquisition in computed tomography is governed ultimately by the principle of As Low As Reasonably

Achievable (ALARA). In the first 10 years of CCTA, the focus was almost exclusively on the detection of

anatomical stenosis in low to intermediate risk patients. With the evolution of technology, the clinical utility

of CCTA has extended beyond stenosis assessment to atherosclerosis characterization, the evaluation of

structural heart disease, and the functional and physiological assessment of coronary stenoses. Recently

the SCCT acquisition guidelines were updated and provide an excellent reference for Cardiac CT imaging

specialists to help optimize their scan protocols. That being said, given the growing information that is

provided from cardiac CT, the imaging requirements have evolved and require tailoring to meet the clinical

indication. The purpose of this white paper is to highlight the parameters and image acquisition protocols that

are important to help optimize image quality, provide accurate representation of anatomy and thus enable

quantitative CT.

Importance of Heart Rate Control

With the advancements in scanner technology, the necessary requirement for heart rate reduction has

decreased over time. The demands for a low and steady heart rate to ensure diagnostic image quality may not

be what they once were but best practice remains to optimize image quality through heart rate control. SCCT

guidelines recommend performing CCTA with heart rates below 60 bpm.

In addition, CCTA no longer simply provides stenosis evaluation but needs to enable the interpreting physician

to identify and characterize plaque and, following the identification of a stenosis, to perform functional or

physiologic evaluation. As a result, while latest generation CT scanners may enable diagnostic image quality

at higher heart rates, there remains meaningful image quality benefits from heart rate reduction. In addition,

lower heart rates allow the use of lower dose scan acquisitions that are not possible at higher heart rates. Heart

rate control strategies are well established and the appropriate strategy is dependent on a number of variables

including available medications, setting of practice and site preference. For recommendations please refer to

the recently updated SCCT acquisition guidelines.

Importance of Nitrates

Nitrates as smooth muscle dilators have direct effect on coronary vasodilation and result in tangible

enlargement of coronary size. As such, similar to invasive coronary catheterization, nitroglycerine (glyceryl

trinitrate) should be administered prior to CCTA to optimize image quality and enable the most accurate

stenosis evaluation. A commonly used regimen is 400-800 µg of sublingual nitroglycerin administered as either

sublingual tablets or a metered lingual spray (commonly 1-2 tablets or 1-2 sprays) prior to the CCTA. While

the evidence is modest and there is no randomized data, both a higher dose and administration via spray are

becoming increasingly preferred in clinical practice and have been shown to help optimize coronary evaluation.

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Selection of Tube Current and Potential

The scan parameters used for any cardiac CT should be tailored to the individual patient but also the intended

application. The image quality issues with the greatest impact on the interpretability of CT are misalignment

and image noise. As such, care must be given to ensure that image noise properties are appropriate and

adequate for accurate lumen segmentation. To do so, tube current and potential should be selected carefully,

guided by chest wall circumference, the iodine concentration of the intravenous contrast medium, and whether

iterative reconstruction is available or not.

Iterative reconstruction (IR) has the ability to reduce image noise in CT without compromising the diagnostic

quality of the CT image dataset, which permits a significant reduction in effective radiation dose. In current

clinical practice, IR has enabled a significant reduction in radiation dose by allowing for a reduction in tube

current and is now increasingly available across all cardiac capable CT scanners. IR commonly takes the form

of a blended reconstruction of IR and filtered back projection (FBP). While a very helpful tool, care should

be given when using a very high percentage of IR for quantitative CT analysis due to the potential impact on

vessel segmentation.

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3. Siemens SOMATOM Definition Flash,

SOMATOM Drive and SOMATOM Force

SOMATOM Definition Flash, SOMATOM Drive and Siemens SOMATOM Force are Dual Source systems

allowing for a heart rate independent temporal resolution of 75 ms for both the SOMATOM Definition Flash

and SOMATOM Drive and 66 ms for the SOMATOM Force.

1. Topogram

General

Data Acquisition (default)

Patient Preparation

AP topogram covering the chest.

• Ref. kVp: 120 kVp

• Patient positioning:

• Qual. ref. mAs: 35 mAs

The following technique provides

patient comfort and optimal image

• Slice/Collimation: 6 x 0.6 mm

quality for the study:

• Length: 512 mm

— Head or feet first, supine with

head, knees, and lower legs

supported by appropriate

accessories.

— Arms raised above the head,

resting comfortably on the head-

arm support.

— The torso of the patient must be

straight, not rotated.

— Torso in the middle of the scan

field, centered with the help of the

laser light markers.

• Place ECG-electrodes, as

anatomically depicted on the

labeled electrodes and IV access

in accordance with institutional

policies.

Recommendation: 18-gauge or

larger intravenous needle in the

right antecubital vein. Automated

contrast injection using a dual-

cylinder injector.

• Provide enough time for the patient

to practice breath hold prior to

acquisition. To avoid breathing

motion artifacts, the patient is

instructed not to breathe and

swallow during the acquisition. It

is necessary to observe the ECG

behavior during the breath hold

procedure. The heart rate may

decrease during the initial seconds

of breath-holding or increase if the

patient is straining to hold his breath

at the end of the scan.

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2. CaSc (optional) - Non-contrast Examination

General

Data Acquisition

Data Reconstruction

Scan range of 12-15 cm from the

• Prospective ECG-triggering

• Axial reconstruction within the ECG

carina to the apex of the heart.

• Ref. kVp: 120 kVp

trigger window, commonly BestDiast

Can be used for subsequent contrast-

• Qual. ref. mAs: 80 mAs

• Field of view limited to the heart

enhanced data acquisition.

• CARE kV: Off

• Slice thickness: 3 mm

Can be used to rule out the presence

• CARE Dose4D^™: on

• Increment: 1.5 mm

of excessive calcification, which may

• Rotation time: 0.28 s (SOMATOM

• WFBP Reconstruction (filtered back

reduce the diagnostic accuracy of the

Definition Flash, SOMATOM Drive)

projection) Convolution kernel:

CTA study.

0.25 s (SOMATOM Force)

B35f (SOMATOM Definition Flash,

SOMATOM Drive) Qr36 (SOMATOM

• Temporal resolution: 75 ms

Force)

(SOMATOM Definition Flash,

SOMATOM Drive) 66 ms

(SOMATOM Force)

• Slice/Collimation: 2 x 128 x 0.6 mm

(SOMATOM Definition Flash,

SOMATOM Drive) 2 x 192 x 0.6 mm

(SOMATOM Force)

• Scan direction cranio-caudal

3. Test Bolus

General

Data Acquisition

A series of sequential scans to

• Delay: 10 s

monitor the arrival of the bolus to

• Ref. kVp: 100 kVp

generate a time density curve. The

• Qual. ref. mAs: 24 mAs

peak of the curve is then used to

• Slice/Collimation: 1 x 10 mm

determine the scanning delay for the

• No. of scans: 15 But can be

CTA acquisition.

suspended when the bolus has

Scans are set up at the level of

passed through the region

ascending aorta at the level of the

carina. The region of interest (ROI) is

placed within the ascending aorta.

A small bolus of contrast plus saline

chaser is injected at the same

flow rate that will be used for CTA

acquisition.

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3.1. Alternatively, CARE Bolus

General

Data Acquisition

CARE Bolus (automatic bolus tracking)

• Delay: 10 s

monitors the attenuation within the

• Ref. kVp: 100 kVp

vessel of interest (ascending aorta).

• Qual. Ref. mAs: 24 mAs

Scans are set up at the level of ascend-

• Slice/Collimation: 1 x 10 mm

ing aorta at the level of the carina.

The full dose of contrast media is

injected at the decided flow rate.

The CTA acquisition is automatically

triggered when the vessel

enhancement reaches the pre-

defined HU level (100- 150HU) above

the baseline. See “Contrast Protocols”

for customers’ best practice.

4. Prospective Adaptive Triggered Sequential Coronary CT Angiography (Heart Rates: up to 80 bpm)

General

Data Acquisition

Data Reconstruction

General ECG triggered Dual Source

If Test Bolus was used:

• Axial reconstruction within the ECG

data acquisition of the heart.

• Delay: time-to-peak value in s

trigger window, commonly

BestDiast.

Scan range of 12-15 cm from the

• Ref. kVp: 100 kVp *

Choose BestSyst and Millisecond

carina to the apex of the heart.

• Qual. Ref. mAs: 380 mAs (Flash)

unit for arrhythmic heart rates.

Use unenhanced CaSc CT data for

300 mAs (Drive) 300 mAs (Force)

• Field of view limited to the heart

planning if available.

• Slice/Collimation: 2 x 128 x 0.6 mm

• Slice thickness: 0.6 mm

(Flash, Drive) 2 x 192 x 0.6 mm

kV will be automatically selected by

(Force)

• Increment: 0.4 mm

CARE kV.

• CARE kV: on

• TrueStack: on

Use TrueStack reconstructions.

• CARE Dose4D^™: on

• Medium smooth convolution kernel

with either filltered back projection:

• ECG Pulsing: auto

B26f Or iterative reconstruction (e.g.

• Scan direction craniocaudal

SAFIRE/ADMIRE, strength ≤ 2)

• Rotation time: 0.28 s (Flash, Drive)

• If the patient has high calcium

0.25 s (Force)

consider a sharper convolution

• Temporal resolution: 75 ms (Flash,

kernel: B46f (Flash, Drive) and

Drive) 66 ms (Force

Bv49 (Force)

• Scan window:

Stable HR

HR < 65 bpm: 70%

HR < 70 bpm: 65%-75%

HR > 70 bpm: 35%-75%

HR > 80 bpm: 30%-40%

Arrhythmic HR

(e.g. atrial fibrillation)

HR < 70 bpm: 250ms-450ms

HR > 70 bpm: 200ms-400ms

* If the patient has high calcium or

stents consider the Care kV setting to

‘Semi’ or adjust the kV to 120

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4.1. Alternatively, Flash/ Turbo Flash Cardio (Heart Rates: Below 62 bpm (Flash/Drive), below 66 bpm (Force), stable HR)

General

Data Acquisition

Data Reconstruction

High pitch (“Flash” “Turbo Flash”)

If Test Bolus was used:

• Axial reconstruction Field of view

single heart beat acquisition.

• Delay: time-to-peak value in s

limited to the heart

Scan range of 12-15 cm from the

• Ref. kVp: 100 kVp *

• Slice thickness: 0.6 mm

carina to the apex of the heart.

• Increment: 0.4 mm

• Qual. ref. mAs: 380 mAs (Flash) 300

Use unenhanced CaSc CT data for

mAs (Drive) 300 mAs (Force)

• Medium smooth convolution kernel

planning if available.

• Slice/Collimation: 2 x 128 x 0.6

with either filtered back projection:

mm (Flash, Drive) 2 x 192 x 0.6 mm

B26f (Flash, Drive) Bv40 (Force) Or

kV will be automatically selected by

(Force)

iterative reconstruction (e.g. SAFIRE

CARE kV.

ADMIRE, strength ≤ 2)

• CARE kV: on *

• If the patient has high calcium

• CARE Dose4D^™: on

consider a sharper convolution

• ECG Pulsing: auto

kernel: B46f (Flash, Drive) and

• Scan direction cranio-caudal

Bv49 (Force)

• Rotation time: 0.28 s (Flash, Drive)

0.25 s (Force)

• Temporal resolution: 75 ms (Flash,

Drive) 66 ms (Force)

• Pitch: 3.4 (Flash, Drive) 3.2 (Force)

* If the patient has high calcium or

stents consider the Care kV setting

to ‘Semi’ or adjust the kV to 120.

5. Contrast Protocol

General

Parameter

Comments

The injection rate should be

Test Bolus

increased for shorter scan times and

• CM Bolus: 10-15mL

larger patients!

• Saline chaser: 40-50mL

CTA requires contrast medium with

• Flow rate: 4-5mL/s

an iodine concentration of at least

(same as during CTA Acquisition)

350 mgI/mL.

cCTA

Place a 20- or 18-gauge IV cannula in

(Generally:)

the RIGHT arm.

• Iodine Concentration:

• 300-370mg Iodine/mL

• Contrast Volume: 50-80mL

• Saline Volume: 50mL

• Flow rate: 4-5mL/s

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4. Siemens SOMATOM Definition AS+ & Edge

Siemens SOMATOM Definition AS+ and Edge are single source systems allowing for a temporal resolution

of 166 ms and optionally 150 ms and 142 ms, respectively, when rotation times of 300 ms and 285 ms are

employed.

1. Topogram

General

Data Acquisition (default)

Patient Preparation

AP topogram covering the chest.

• Ref. kVp: 120 kVp

• Patient positioning:

• Qual. ref. mAs: 35 mAs

The following technique provides

• Slice/Collimation: 6 x 0.6 mm

patient comfort and optimal image

quality for the study:

• Length: 512 mm

— Head or feet first, supine with

head, knees, and lower legs

supported by appropriate

accessories.

— Arms raised above the head,

resting comfortably on the head-

arm support.

— The torso of the patient must be

straight, not rotated.

— Torso in the middle of the scan

field, centered with the help of the

laser light markers.

• Place ECG-electrodes, as

anatomically depicted on the

labeled electrodes and IV access

in accordance with institutional

policies.

Recommendation: 18-gauge or

larger intravenous needle in the

right antecubital vein. Automated

contrast injection using a dual-

cylinder injector.

• Provide enough time for the patient

to practice breath hold prior to

acquisition. To avoid breathing

motion artifacts, the patient is

instructed not to breathe and

swallow during the acquisition. It

is necessary to observe the ECG

behavior during the breath hold

procedure. The heart rate may

decrease during the initial seconds

of breath-holding or increase if the

patient is straining to hold his breath

at the end of the scan.

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2. CaSc (optional) - Non-contrast Examination

General

Data Acquisition

Data Reconstruction

Scan range of 12-15 cm from the

• Prospective ECG-triggering

• Axial reconstruction within the ECG

carina to the apex of the heart.

• Ref. kVp: 120 kVp

trigger window, commonly BestDiast

Can be used for subsequent contrast-

• Qual. ref. mAs: 40 mAs

• Field of view limited to the heart

enhanced data acquisition.

• CARE kV: semi

• Slice thickness: 3 mm

Can be used to rule out the presence

• CARE Dose4D^™: on

• Increment: 1.5 mm

of excessive calcification, which may

• Rotation time: 0.30 s (SOMATOM

• WFBP Reconstruction (Filtered

reduce the diagnostic accuracy of the

Definition AS+)

Backprojection) Convolution kernel:

CTA study.

0.28 s (SOMATOM Definition Edge)

B35f

• Temporal resolution: 150 ms

(SOMATOM Definition AS+)

142 ms (SOMATOM Definition

Edge)

• Slice/Collimation: 128 x 0.6 mm

• Scan direction cranio-caudal

3. Test Bolus

General

Data Acquisition

A series of sequential scans to

• Delay: 10 s

monitor the arrival of the bolus to

• Ref. kVp: 100 kVp

generate a time density curve. The

• Qual. ref. mAs: 30 mAs

peak of the curve is then used to

• Slice/Collimation: 1 x 10 mm

determine the scanning delay for the

• No. of scans: 15

CTA acquisition.

But can be suspended when the

Scans are set up at the level of

bolus has passed through the region

ascending aorta at the level of the

carina. The region of interest (ROI) is

placed within the ascending aorta.

A small bolus of contrast plus saline

chaser is injected at the same

flow rate that will be used for CTA

acquisition.

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3.1. Alternatively, CARE Bolus

General

Data Acquisition

CARE Bolus (automatic bolus tracking)

• Delay: 10 s

monitors the attenuation within the

• Ref. kVp: 100 kVp

vessel of interest (ascending aorta).

• Qual. Ref. mAs: 30 mAs

Scans are set up at the level of ascend-

• Slice/Collimation: 1 x 10 mm

ing aorta at the level of the carina.

The full dose of contrast media is

injected at the decided flow rate.

The CTA acquisition is automatically

triggered when the vessel enhance-

ment reaches the pre-defined HU level

(100- 150HU) above the baseline.

4. Prospective Adaptive Triggered Sequential Coronary CT Angiography (Heart Rates: up to 70 bpm)

General

Data Acquisition

Data Reconstruction

General ECG triggered data

If Test Bolus was used:

• Axial reconstruction within the ECG

acquisition of the heart.

• Delay: time-to-peak value in s

trigger window, commonly

BestDiast.

Scan range of 12-15 cm from the

• Ref. kVp: 100 kVp

Choose BestSyst and Millisecond

carina to the apex of the heart.

• Qual. Ref. mAs:190 mAs (AS+)

unit for arrhythmic heart rates

150 mAs (Edge)

Use unenhanced CaSc CT data for

• Field of view limited to the heart

planning if available.

• Slice/Collimation: 128 x 0.6 mm

• Slice thickness: 0.6 mm

• CARE kV: on *

kV will be automatically selected by

• Increment: 0.4 mm

CARE kV.

• CARE Dose4D^™: on

• TrueStack: on

Use TrueStack reconstructions.

• ECG Pulsing: auto

• Medium smooth convolution kernel

• Scan direction craniocaudal

with either filltered back projection:

• Rotation time: 0.30 s (AS+)

B26f Or iterative reconstruction (e.g.

0.28 s (Edge)

SAFIRE/ADMIRE, strength ≤ 2)

• Temporal resolution: 150 ms (AS+)

• If the patient has high calcium

142 ms (Edge)

consider a sharper convolution

• Scan window:

kernel

Stable HR

HR < 70 bpm: 60%-80%

Arrhythmic HR

(e.g. atrial fibrillation)

HR < 70 bpm: 200-400 ms

For HRs > 70 bpm switch to

retrospective gated cCTA with same

parameter settings

* If the patient has high calcium or

stents consider the Care kV setting to

‘Semi’ or adjust the kV to 120

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5. Contrast Protocol

General

Parameter

Comments

The injection rate should be

Test Bolus

increased for shorter scan times and

• CM Bolus: 10-15mL

larger patients!

• Saline chaser: 40-50mL

CTA requires contrast medium with

• Flow rate: 4-5mL/s

an iodine concentration of at least

(same as during CTA Acquisition)

350 mgI/mL.

cCTA

Place a 20- or 18-gauge IV cannula in

(Generally:)

the RIGHT arm.

• Iodine Concentration:

• 300-370mg Iodine/mL

• Contrast Volume: 50-80mL

• Saline Volume: 50mL

• Flow rate: 4-5mL/s

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5. Siemens SOMATOM go.Top

Siemens SOMATOM go.Top is a single source system allowing for a temporal resolution of 165 ms, when

rotation times of 330 ms are employed.

1. Topogram

General

Data Acquisition (default)

Patient Preparation

AP topogram covering the chest.

• Sn100 kV; 60 mA

• Patient positioning:

• Scan mode:

The following technique provides

ScanplanningTopoAdultSn

patient comfort and optimal image

quality for the study:

• Length: 512 mm

— Head or feet first, supine with

head, knees, and lower legs

supported by appropriate

accessories.

— Arms raised above the head, resting

comfortably on the headarm

support.

— The torso of the patient must be

straight, not rotated.

— Torso in the middle of the scan field,

centered with the help of the laser

light markers.

• Place ECG-electrodes, as

anatomically depicted on the

labeled electrodes and IV access

in accordance with institutional

policies.

Recommendation: 18-gauge or

larger intravenous needle in the

right antecubital vein. Automated

contrast injection using a dual-

cylinder injector.

• Provide enough time for the patient

to practice breath hold prior to

acquisition. To avoid breathing

motion artifacts, the patient is

instructed not to breathe and

swallow during the acquisition. It

is necessary to observe the ECG

behavior during the breath hold

procedure. The heart rate may

decrease during the initial seconds

of breath-holding or increase if the

patient is straining to hold his breath

at the end of the scan.

HeartFlow, Inc.

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2. CaSc (optional) - Non-contrast Examination

General

Data Acquisition

Data Reconstruction

Scan range of 12-15 cm from the

• Prospective ECG-triggering

• Axial reconstruction within the ECG

carina to the apex of the heart .

• CARE Dose4D™ & CARE kV:

trigger window, commonly BestDiast

Can be used for subsequent

Manual kV

• Field of view limited to the heart

contrastenhanced data acquisition.

• Qual. ref. mAs @ 120 kV: 20 mAs

• Slice thickness: 3 mm

• Scan mode: CardiacSequenceAdult

• Increment: 1.5 mm

Can be used to rule out the presence

of excessive calcification, which may

• Scan direction cranio-caudal

• WFBP Reconstruction (Filtered

reduce the diagnostic accuracy of the

Backprojection) Convolution kernel:

CTA study.

Qr36

3. Test Bolus

General

Data Acquisition

A series of sequential scans to

• Delay: 8 s

monitor the arrival of the bolus to

• CARE Dose4D™ & CARE kV:

generate a time density curve. The

Manual kV

peak of the curve is then used to

• Qual. ref. mAs @ 120 kV: 20 mAs

determine the scanning delay for the

• Slice/Collimation: 1 x 10 mm

CTA acquisition.

• Scan mode:

Scans are set up at the level of

BolusSequenceAdult2d

ascending aorta at the level of the

• No. of scans: 15

carina. The region of interest (ROI) is

• Cycle time: 1.5 s

placed within the ascending aorta.

But can be suspended when the

A small bolus of contrast plus saline

bolus has passed through the region

chaser is injected at the same

flow rate that will be used for CTA

acquisition.

3.1. Alternatively, CARE Bolus

General

Data Acquisition

CARE Bolus (automatic bolus

• Delay: 10 s

tracking) monitors the attenuation

• CARE Dose4D™ & CARE kV:

within the vessel of interest

Manual kV

(ascending aorta). Scans are set

• Qual. ref. mAs @ 120 kV: 20 mAs

up at the level of ascending aorta

• Slice/Collimation: 1 x 10 mm

at the level of the carina. The full

• Scan mode:

dose of contrast media is injected

BolusSequenceAdult2d

at the decided flow rate. The CTA

acquisition is automatically triggered

when the vessel enhancement

reaches the pre-defined HU level

(100- 150HU) above the baseline.

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4. Coronary CT Angiography (Heart Rates: up to 70 bpm)

General

Data Acquisition

Data Reconstruction

General ECG triggered data

If Test Bolus was used:

Axial reconstruction within the ECG

acquisition of the heart.

• Delay: time-to-peak value in s + 3 s

trigger window, commonly BestDiast.

Choose BestSyst and Millisecond unit

Scan range of 12-15 cm from the

• CARE Dose4D™ & CARE kV*: Full

for arrhythmic heart rates

carina to the apex of the heart.

• Qual. Ref. mAs @ 120 kV: 70 mAs

• Field of view limited to the heart

Use unenhanced CaSc CT data

+ different geometry of systems

• Slice thickness: 0.8 mm

for planning if available. kV will be

• Scan mode:

• Increment: 0.5 mm

automatically selected by CARE kV.

CardiacSpiralAdultAngio

• Medium smooth convolution kernel

• ECG Pulsing: Standard

with either filtered back projection:

• Pulsing window:

Bv40 or iterative reconstruction (e.g.

Stable HR

SAFIRE/ADMIRE, strength ≤ 2)

HR < 70 bpm: 65%-85%

• If the patient has high calcium

HR > 70 bpm: 30%-80%

consider a sharper convolution

Arrhythmic HR

kernel (Bv49)

(e.g. atrial fibrillation)

• Enable TrueStack option to be

250-450 ms

switched on

* If the patient has high calcium or

stents consider the CARE kV setting

to ‘Manual kV’ or adjust the kV to

values equal to 120 kV. Additionally

define the minimum voltage for

CARE kV in the scan protocol

assistant to be 80 kV for adults.

5. Contrast Protocol

General

Data Acquisition

The injection rate should be

Test Bolus

increased for shorter scan times and

• CM Bolus: 10-15mL

larger patients!

• Saline chaser: 40-50mL

CTA requires contrast medium with

• Flow rate: 4-5mL/s

an iodine concentration of at least

(same as during CTA Acquisition)

350 mgI/mL.

cCTA

Place a 20- or 18-gauge IV cannula in

(Generally:)

the RIGHT arm.

• Iodine Concentration:

• 300-370mg Iodine/mL

• Contrast Volume: 50-80mL

• Saline Volume: 50mL

• Flow rate: 4-5mL/s

HeartFlow, Inc.

| Acquisition and Reconstruction Techniques for Coronary CT Angiography: Siemens Healthineers Scanner Platforms

15991236 V2

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This paper is presented as a service to medical personnel by HeartFlow and Siemens. The information in this white paper has been compiled

from available literature and best practices from expert users. Although every effort has been made to faithfully convey this information, the

editors and publisher cannot be held responsible for their correctness. This paper is not intended to be, and should not be construed as,

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be consulted. HeartFlow and the editors disclaim any liability arising directly or indirectly from the use of drugs, devices, techniques, or

procedures described in this paper.

WARNING: Any references to x-ray exposure, intravenous contrast dosage, and other medication are intended as reference guidelines only.

The guidelines in this document do not substitute for the judgment of a trained healthcare provider. Each scan requires medical judgment by

the healthcare provider about exposing the patient to ionizing radiation. Use the As Low As Reasonably Achievable (ALARA) radiation dose

principle to balance factors such as the patient’s condition, size and age; region to be imaged; and diagnostic task.

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