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. Reference Protocol: Aquilion

1. Scanogram

General

Data Acquisition

Comments

Lateral and AP scout covering the

• AP Scanogram: 120kVp/50mA

Position the patient for AP scanogram

heart and coronaries

• Lat Scanogram: 120kVp/100mA

to acquire AP and lateral scanograms.

Offset the patient to the right so the

• Auto Voice (Breath hold command):

heart is at the center of the scan field.

Place the patient's arms above their

head with the ECG leads outside the

scan range.

Have the patient practice breath-

holding before starting the

examination. This should be a single

"breathe in and hold" command.

The patient should be instructed

to hold their breath at about 75%

of maximum lung capacity (“take a

comfortable breath in”) and to take

the same size breath each time they

are told. This important step has two

purposes: To ensure that the patient

can hold their breath for the required

scan time. To monitor the patient's

heart rate during breath-holding.

Make sure that a steady heart rate is

displayed with a clean ECG signal.

2. Non-enhanced Scan (optional) - Calcium Score

General

Data Acquisition

Data Reconstruction

• Can be used for quantification of

Helical CCTA Acquisition

Coronary CTA (Acquisition)

annular calcification

• Acquisition mode: Ca Score

• Field of View limited to the heart

• Can be used for planning of

Volume Mode

(200-220 mm)

subsequent contrast-enhanced

• Tube Voltage: 120kVp

• Slice thickness 0.5mm

data acquisition

• Tube Current: ^SUREExposure

• Increment 0.25mm

• Volume data can be acquired as a

• R-R Scanning Window:

• SUREIQ: Ca Score

single-beat/one rotation scan

HR<71BPM (75%)

FC -12

HR>71BPM (40%)

OSR - Cardiac

Determined by scanner

Dose Reduction - OFF

• Slice/Collimation: 0.5/240 (120mm)

Filter - OFF

• Rotation time:

Aquilion One 640 - 350msec

Aquilion One Vision: 275msec

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3. ECG Gated CTA

a. kV and mA

General

Data Acquisition

Data Reconstruction

From the calcium scoring

• Tube Voltage: 120kVp (the kV can

• Low Dose CTA mode is a low-

examination, select the start and end

be adjusted by selecting the lowest

dose scanning technique in which

positions, the same scanogram can

kV where the graph does not reach

exposure is performed for only a

be used as the Calcium scan.

the maximum)

portion of the R-R interval (general

diastole). The desired exposure

It is advisable to plan 1 cm above the

• Tube Current: ^SUREExposure Cardiac

phase is set as a percentage of the

superior image selected and 1 cm

recommendations

R-R interval, so the actual exposure

below the inferior image selected in

SD - 33

time varies depending on the

case the patient's breath-holding is

^SUREIQ - Cardiac CTA

patient’s heart rate. The exposure

inconsistent. Note: that the proximal

Max mA - 580

phase setting can be expanded

LAD is often located superior to the

Min mA - 40

to include systole if the heart rate

origin of the left main coronary artery

• Open the ^SURECardio menu and

is high, and a function is provided

Can be used for quantification of

click the ‘Breath Ex’, this monitors

to perform such setting based on

annular calcification

the patient’s heart rate during

the results of breathing exercise.

breath-hold training

Multisegments reconstruction is

also available for patients with high

heart rates. Functional analysis is not

possible in this scan mode because

exposure does not cover the entire

R-R interval.

b. Timing: Acquiring the ^SUREStart S and V

General

Data Acquisition

Data Reconstruction

•

Confirm that the descending aorta

•

OPTION You may prefer to trigger

can be clearly identified on the

^SUREStart using manual mode.

^SUREstart slice.

Triggering ^SUREStart in manual mode

•

Place the ^SUREStart ROI over the

is easy, but you need to be confident

descending aorta as shown above

of your anatomy. Remember that

you will still get a graphical readout

•

Set the ^SUREStart trigger at 180 HU

of the ROI density. In manual mode,

you can easily compensate for low

cardiac output by delaying the start

of scanning. Place the ^SUREStart ROI

over the descending aorta as shown

above

•

Reassure the patient that it is normal

to experience a sensation of warmth

following contrast administration.

Inform the patient that the next

breath-hold is the last one for the

examination. Confirm that the

patient's heart rate is steady. It is a

good idea to have someone monitor

the first few seconds of contrast

administration to avoid extravasation.

GO Contrast injection and scanning

are started simultaneously

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c. Cardiac Reconstructions

General

Data Acquisition

Data Reconstruction

phaseXact - Fully automated phase

• Phase selection is performed in the

• After the eXam Plan is completed,

selection software

raw data domain and requires no

phaseXact finds and reconstructs

operator intervention.

the best motion-free cardiac phase.

The phaseXact software automatically

• phaseXact is set ON in the

It may be necessary to reconstruct

determines the optimal cardiac phase

eXamplan.

other phases to create a temporal

for motion-free imaging.

window to permit better assessment

• Select “Best Phase”.

The concept of imageXact is to

of the proximal and distal arteries.

perform reconstruction at an absolute

• imageXact - Guided image-based

time point after the R wave (R + ms).

phase selection software

Phase selection is performed using a

• In rare cases, phaseXact may not

single image located at the mid-heart

be able to automatically determine

level and reconstructed throughout

the best motion-free cardiac phase.

the entire cardiac cycle.

In such cases, imageXact can help

by guiding the operator through a

simple and precise manual phase

selection process.

^SUREIQ Settings

The following ^SUREIQ settings are recommended for cardiac reconstructions:

^SUREIQ

OSR

Dose Reduction

Filter

CTA

Cardiac

AIDR 3D

OFF

Stent

Cardiac

AIDR 3D

OFF

Low Dose

Cardiac

AIDR 3D

OFF

4. Contrast Protocol

General

Data Acquisition

Comments

The injection rate should be

Set the ^SUREStart trigger at 180 HU

Single Phase Contrast with Saline

increased for shorter scan times and

Flush This protocol ensures complete

larger patients!

washout of the right side of the heart.

Streak artifacts from undiluted contrast

CTA requires contrast medium with

medium are eliminated, providing

an iodine concentration of at least

excellent visualization of the RCA. The

350 mgI/mL.

saline solution replaces about 20 mL

Place a 20- or 18-gauge IV cannula in

(5 seconds of injection) of the contrast

the RIGHT arm.

medium.

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4. Contrast Protocol (contd.)

General

Contrast Formula

Comments

The injection rate should be

Biphasic Injection with

Biphasic Injection with a Contrast/Saline

increased for shorter scan times and

Contrast/Saline Mix

Mix A biphasic injection protocol with

larger patients!

(Maintains right heart contrast for CFA)

a contrast/saline mix reduces streak

artifact in the SVC and right heart, but

CTA requires contrast medium with

Phase 1 (Contrast)

maintains adequate opacification of the

an iodine concentration of at least

60 mL @ 4 mL/s* (15 s) @ 4 mL/s

right ventricle. This may improve the

350 mgI/mL.

detection of the ventricular septal wall

Phase 2 (Mix)

Place a 20- or 18-gauge IV cannula in

for CFA.

50% Contrast + 50% Saline

the RIGHT arm.

XX = (Scan Time s) x 4

(Simultaneous injection of contrast

@2mL/s & saline @2mL/s)

XX = (Scan Time s) x 4

In the above formula, the duration of

mixed injection = scan time

* The Injection rate should be increased for larger patients to ensure adequate iodine flux and therefore good

arterial enhancement.

The following guidelines are suggested for injection rates:

Weight (kilograms)

Weight (pounds)

Injection Rate

< 59 kg

< 129 lb

3.5 mL/s

60 - 100 kg

130 - 219 lb

4 mL/s

> 100 kg

> 220 lb

5 mL/s

Review of Data Reconstruction and ECG-Editing

• Image reconstructions of the heart should be reviewed immediately after the scan when raw data is

still available 

• The ECG-gating should be reviewed to ensure that the automated algorithms correctly identified the

R-peaks 

• If R-peaks were not correctly identified, manual correction should be performed (e.g. add an R-peak if an

R-peak was not identified, or delete an R-peak if an R-peak was placed on anything other than the R-peak;

alternatively R-peaks can be shifted manually) 

• In case of ectopic contractions, absolute ms reconstruction should be used and the R-peak of the ectopic

beat should be deleted 

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4. Bibliography

Dewey M, Hoffmann H, Hamm B. Multislice CT coronary angiography: effect of sublingual nitroglycerine

on the diameter of coronary arteries. RoFo: Fortschritte auf dem Gebiete der Rontgenstrahlen und der

Nuklearmedizin. 2006;178(6):600-4.

Decramer I, Vanhoenacker PK, Sarno G, Van Hoe L, Bladt O, Wijns W, et al. Effects of sublingual

nitroglycerin on coronary lumen diameter and number of visualized septal branches on 64-MDCT

angiography. American Journal of Roentgenology. 2008;190(1):219-25.

Laslett LJ, Baker L. Sublingual nitroglycerin administered by spray versus tablet: comparative timing of

hemodynamic effects. Cardiology. 1990;77(4):303-10.

Bachmann KF, Gansser RE. Nitroglycerin oral spray: evaluation of its coronary artery dilative action by

quantitative angiography. The American journal of cardiology. 1988;61(9):7E-11E.

Sato K, et al. Optimal starting time of acquisition and feasibility of complementary administration of

nitroglycerin with intravenous beta-blocker in multislice computed tomography. JCCT. 2009;33(2):193)

Abbara S, Blanke P, Maroules CD, Cheezum M, Choi AD, Han BK, Marwan M, Naoum C, Norgaard BL,

Rubinshtein R, Schoenhagen P, Villines T, Leipsic J. SCCT guidelines for the performance and acquisition

of coronary computed tomographic angiography: A report of the society of Cardiovascular Computed

Tomography Guidelines Committee: Endorsed by the North American Society for Cardiovascular Imaging

(NASCI). J Cardiovasc Comput Tomogr. 2016 Oct 12. pii: S1934-5925(16)30239-8.

Leipsic J, Abbara S, Achenbach S, Cury R, Earls JP, Mancini GJ, et al. SCCT guidelines for the interpretation

and reporting of coronary CT angiography: a report of the Society of Cardiovascular Computed

Tomography Guidelines Committee. Journal of cardiovascular computed tomography. 2014;8(5):342-58.

Budoff MJ, Dowe D, Jollis JG, Gitter M, Sutherland J, Halamert E, et al. Diagnostic performance of

64-multidetector row coronary computed tomographic angiography for evaluation of coronary artery

stenosis in individuals without known coronary artery disease: results from the prospective multicenter

ACCURACY (Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing

Invasive Coronary Angiography) trial. Journal of the American College of Cardiology. 2008;52(21):1724-32.

Meijboom WB, Meijs MF, Schuijf JD, Cramer MJ, Mollet NR, van Mieghem CA, et al. Diagnostic accuracy

of 64-slice computed tomography coronary angiography: a prospective, multicenter, multivendor study.

Journal of the American College of Cardiology. 2008;52(25):2135-44.

10. Miller JM, Rochitte CE, Dewey M, Arbab-Zadeh A, Niinuma H, Gottlieb I, et al. Diagnostic performance of

coronary angiography by 64-row CT. The New England journal of medicine. 2008;359(22):2324-36.

11. Min JK, Shaw LJ, Devereux RB, Okin PM, Weinsaft JW, Russo DJ, et al. Prognostic value of multidetector

coronary computed tomographic angiography for prediction of all-cause mortality. Journal of the

American College of Cardiology. 2007;50(12):1161-70.

HeartFlow, Inc.

| Acquisition and Reconstruction Techniques for Coronary CT Angiography: Canon Medical Systems Scanner Platforms

15991228 V2

12. Min JK, Dunning A, Lin FY, Achenbach S, Al-Mallah M, Budoff MJ, et al. Age- and sex-related differences

in all-cause mortality risk based on coronary computed tomography angiography findings results from

the International Multicenter CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An

International Multicenter Registry) of 23,854 patients without known coronary artery disease. Journal of the

American College of Cardiology. 2011;58(8):849-60.

13. Villines TC, Hulten EA, Shaw LJ, Goyal M, Dunning A, Achenbach S, et al. Prevalence and severity of

coronary artery disease and adverse events among symptomatic patients with coronary artery calcification

scores of zero undergoing coronary computed tomography angiography: results from the CONFIRM

(Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter) registry. Journal

of the American College of Cardiology. 2011;58(24):2533-40.

14. Leipsic J, Taylor CM, Gransar H, Shaw LJ, Ahmadi A, Thompson A, et al. Sex-based prognostic implications

of nonobstructive coronary artery disease: results from the international multicenter CONFIRM study.

Radiology. 2014;273(2):393-400.

15. Taylor AJ, Cerqueira M, Hodgson JM, Mark D, Min J, O'Gara P, et al. ACCF/SCCT/ACR/AHA/ASE/

ASNC/NASCI/SCAI/SCMR 2010 appropriate use criteria for cardiac computed tomography. A report

of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society

of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart

Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology,

the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and

Interventions, and the Society for Cardiovascular Magnetic Resonance. Journal of the American College of

Cardiology. 2010;56(22):1864-94.

16. Jacobs JE, Boxt LM, Desjardins B, Fishman EK, Larson PA, Schoepf J, et al. ACR practice guideline for the

performance and interpretation of cardiac computed tomography (CT). Journal of the American College of

Radiology : JACR. 2006;3(9):677-85.

17. Halliburton SS, Abbara S, Chen MY, Gentry R, Mahesh M, Raff GL, et al. SCCT guidelines on radiation dose

and dose-optimization strategies in cardiovascular CT. Journal of cardiovascular computed tomography.

2011;5(4):198-224.

18. Valentin J. Pregnancy and medical radiation: ICRP publication 84. . Ann ICRP 2000(30(1)):1-39.

19. Chen MM, Coakley FV, Kaimal A, Laros RK, Jr. Guidelines for computed tomography and magnetic

resonance imaging use during pregnancy and lactation. Obstet Gynecol. 2008;112(2 Pt 1):333-340.

20. Woussen S1, Lopez-Rendon X, Vanbeckevoort D, Bosmans H, Oyen R, Zanca F. Clinical indications and

radiation doses to the conceptus associated with CT imaging in pregnancy: a retrospective study. Eur

Radiol. 2015 Jul 23.

21. Webb JA, Thomsen HS, Morcos SK, Members of Contrast Media Safety Committee of European Society

of Urogenital R. The use of iodinated and gadolinium contrast media during pregnancy and lactation.

European radiology. 2005;15(6):1234-40.

HeartFlow, Inc.

| Acquisition and Reconstruction Techniques for Coronary CT Angiography: Canon Medical Systems Scanner Platforms

15991228 V2

22. Rubin G, Bluemke D, Duerinckx A, Flamm S, Grist T, Jacobs J, et al. ACR Committee on Cardiac Imaging.

Practice guideline for the performance and interpretation of cardiac computed tomography (CT). (Res. 10,

16g, 17, 34, 35, 36 - 2006) In: Practice Guidelines and Technical Standards. Reston, VA: American College

of Radiology. 2008;421-30.

23. Greenberger P, Patterson R. Prednisone-diphenhydramine regimen prior to use of radiographic contrast

media. The Journal of allergy and clinical immunology. 1979;63(4):295.

24. Zeiher AM, Schachinger V, Minners J. Long-term cigarette smoking impairs endothelium-dependent

coronary arterial vasodilator function. Circulation. 1995;92(5):1094-100.

25. Quillen JE, Rossen JD, Oskarsson HJ, Minor RL, Jr., Lopez AG, Winniford MD. Acute effect of cigarette

smoking on the coronary circulation: constriction of epicardial and resistance vessels. Journal of the

American College of Cardiology. 1993;22(3):642-7.

26. Elicker BM, Cypel YS, Weinreb JC. IV contrast administration for CT: a survey of practices for the screening

and prevention of contrast nephropathy. AJR American journal of roentgenology. 2006;186(6):1651-8.

27. Lee JK, Warshauer DM, Bush WH, Jr., McClennan BL, Choyke PL. Determination of serum creatinine

level before intravenous administration of iodinated contrast medium. A survey. Investigative radiology.

1995;30(12):700-5.

28. Owen RJ, Hiremath S, Myers A, Fraser-Hill M, Barrett BJ. Canadian Association of Radiologists consensus

guidelines for the prevention of contrast-induced nephropathy: update 2012. Canadian Association of

Radiologists journal = Journal l'Association canadienne des radiologistes. 2014;65(2):96-105.

29. Owen at al. Canadian Association of Radiologists consensus guidelines for the prevention of contrast-

induced nephropathy. Can Assoc Radiol J. 2014 May;65(2):96-105

30. Briguori C, Airoldi F, D'Andrea D, Bonizzoni E, Morici N, Focaccio A, et al. Renal Insufficiency Following

Contrast Media Administration Trial (REMEDIAL): a randomized comparison of 3 preventive strategies.

Circulation. 2007;115(10):1211-7.

31. Briguori C, Colombo A, Violante A, Balestrieri P, Manganelli F, Paolo Elia P, et al. Standard vs double

dose of N-acetylcysteine to prevent contrast agent associated nephrotoxicity. European heart journal.

2004;25(3):206-11.

32. Lee PT, Chou KJ, Liu CP, Mar GY, Chen CL, Hsu CY, et al. Renal protection for coronary angiography in

advanced renal failure patients by prophylactic hemodialysis. A randomized controlled trial. Journal of the

American College of Cardiology. 2007;50(11):1015-20.

33. Marenzi G, Assanelli E, Marana I, Lauri G, Campodonico J, Grazi M, et al. N-acetylcysteine and contrast-

induced nephropathy in primary angioplasty. The New England journal of medicine. 2006;354(26):2773-82.

34. McDonald R, Mdcondal J, Bida Jet al Intravenous Contrast Material-induced Nephropathy:

35. Causal or Coincident Phenomenon?. RadiologyVolume 267: Number 1—April 2013

HeartFlow, Inc.

| Acquisition and Reconstruction Techniques for Coronary CT Angiography: Canon Medical Systems Scanner Platforms

15991228 V2

36. Newhouse JH, Kho D, Rao QA, Starren J. Frequency of serum creatinine changes in the absence of

iodinated contrast material: implications for studies of contrast nephrotoxicity. AJR American journal of

roentgenology. 2008;191(2):376-82.

37. McDonald RJ, McDonald JS, Carter RE, Hartman RP, Katzberg RW, Kallmes DF, et al. Intravenous contrast

material exposure is not an independent risk factor for dialysis or mortality. Radiology. 2014;273(3):714-25.

38. Owen RJ, Hiremath S, Myers A, Fraser-Hill M, Barrett BJ. Canadian Association of Radiologists consensus

guidelines for the prevention of contrast-induced nephropathy: update 2012. Canadian Association of

Radiologists journal = Journal l'Association canadienne des radiologistes. 2014;65(2):96-105.

39. Ahuja TS, Niaz N, Agraharkar M. Contrast-induced nephrotoxicity in renal allograft recipients. Clinical

nephrology. 2000;54(1):11-4.

40. Brodoefel H, Reimann A, Heuschmid M, Kuttner A, Beck T, Burgstahler C, et al. Non-invasive coronary

angiography with 16-slice spiral computed tomography: image quality in patients with high heart rates.

European radiology. 2006;16(7):1434-41.

41. Cademartiri F, Mollet NR, Runza G, Belgrano M, Malagutti P, Meijboom BW, et al. Diagnostic accuracy of

multislice computed tomography coronary angiography is improved at low heart rates. The international

journal of cardiovascular imaging. 2006;22(1):101-5; discussion 7-9.

42. Achenbach S, Manolopoulos M, Schuhback A, Ropers D, Rixe J, Schneider C, et al. Influence of heart rate

and phase of the cardiac cycle on the occurrence of motion artifact in dual-source CT angiography of the

coronary arteries. Journal of cardiovascular computed tomography. 2012;6(2):91-8.

43. Le Jemtel TH, Padeletti M, Jelic S. Diagnostic and therapeutic challenges in patients with coexistent chronic

obstructive pulmonary disease and chronic heart failure. Journal of the American College of Cardiology.

2007;49(2):171-80.

44. Maffei E, Palumbo AA, Martini C, Tedeschi C, Tarantini G, Seitun S, et al. "In-house" pharmacological

management for computed tomography coronary angiography: heart rate reduction, timing and safety of

different drugs used during patient preparation. European radiology. 2009;19(12):2931-40.

45. Roberts WT, Wright AR, Timmis JB, Timmis AD. Safety and efficacy of a rate control protocol for cardiac CT.

The British journal of radiology. 2009;82(976):267-71.

46.

40. Earls et al JCCT Metoprolol

47. Sadamatsu K, Koide S, Nakano K, Yoshida K. Heart rate control with single administration of a long-acting

beta-blocker at bedtime before coronary computed tomography angiography. Journal of cardiology.

2015;65(4):293-7.

48. Clayton B, Raju V, Roobottom C, Morgan-Hughes G. Safety of intravenous beta-adrenoceptor blockers for

computed tomographic coronary angiography. British journal of clinical pharmacology. 2015;79(3):533-6.

49. Kassamali RH, Kim DH, Patel H, Raichura N, Hoey ET, Hodson J, et al. Safety of an i.v. beta-adrenergic

blockade protocol for heart rate optimization before coronary CT angiography. AJR American journal of

roentgenology. 2014;203(4):759-62.

HeartFlow, Inc.

| Acquisition and Reconstruction Techniques for Coronary CT Angiography: Canon Medical Systems Scanner Platforms

15991228 V2

50. Wang JD, Zhang HW, Xin Q, Yang JJ, Sun ZJ, Liu HB, et al. Safety and efficacy of intravenous esmolol before

prospective electrocardiogram-triggered high-pitch spiral acquisition for computed tomography coronary

angiography. Journal of geriatric cardiology : JGC. 2014;11(1):39-43.

51. Dobre D, Borer JS, Fox K, Swedberg K, Adams KF, Cleland JG, et al. Heart rate: a prognostic factor and

therapeutic target in chronic heart failure. The distinct roles of drugs with heart rate-lowering properties.

European journal of heart failure. 2014;16(1):76-85.

52. Pichler P, Pichler-Cetin E, Vertesich M, Mendel H, Sochor H, Dock W, et al. Ivabradine versus metoprolol

for heart rate reduction before coronary computed tomography angiography. The American journal of

cardiology. 2012;109(2):169-73.

53. Celik O, Atasoy MM, Erturk M, Yalcin AA, Aksu HU, Diker M, et al. Comparison of different strategies of

ivabradine premedication for heart rate reduction before coronary computed tomography angiography.

Journal of cardiovascular computed tomography. 2014;8(1):77-82.

54. Guaricci AI, Schuijf JD, Cademartiri F, Brunetti ND, Montrone D, Maffei E, et al. Incremental value and safety

of oral ivabradine for heart rate reduction in computed tomography coronary angiography. International

journal of cardiology. 2012;156(1):28-33.

55. Guaricci AI, Maffei E, Brunetti ND, Montrone D, Di Biase L, Tedeschi C, et al. Heart rate control with oral

ivabradine in computed tomography coronary angiography: a randomized comparison of 7.5 mg vs 5 mg

regimen. International journal of cardiology. 2013;168(1):362-8.

56. Adile KK, Kapoor A, Jain SK, Gupta A, Kumar S, Tewari S, et al. Safety and efficacy of oral ivabradine as

a heart rate-reducing agent in patients undergoing CT coronary angiography. The British journal of

radiology. 2012;85(1016):e424-8.

57. Cademartiri F, Garot J, Tendera M, Zamorano JL. Intravenous ivabradine for control of heart rate during

coronary CT angiography: A randomized, double-blind, placebo-controlled trial. Journal of cardiovascular

computed tomography. 2015;9(4):286-94.

58. Parker JD, Parker JO. Nitrate therapy for stable angina pectoris. The New England journal of medicine.

1998;338(8):520-31.

59. Dewey M, Hoffmann H, Hamm B. Multislice CT coronary angiography: effect of sublingual nitroglycerine

on the diameter of coronary arteries. RoFo : Fortschritte auf dem Gebiete der Rontgenstrahlen und der

Nuklearmedizin. 2006;178(6):600-4.

60. Decramer I, Vanhoenacker PK, Sarno G, Van Hoe L, Bladt O, Wijns W, et al. Effects of sublingual

nitroglycerin on coronary lumen diameter and number of visualized septal branches on 64-MDCT

angiography. AJR American journal of roentgenology. 2008;190(1):219-25.

61. Laslett LJ, Baker L. Sublingual nitroglycerin administered by spray versus tablet: comparative timing of

hemodynamic effects. Cardiology. 1990;77(4):303-10.

62. Bachmann KF, Gansser RE. Nitroglycerin oral spray: evaluation of its coronary artery dilative action by

quantitative angiography. The American journal of cardiology. 1988;61(9):7E-11E.

HeartFlow, Inc.

| Acquisition and Reconstruction Techniques for Coronary CT Angiography: Canon Medical Systems Scanner Platforms

15991228 V2

63. Sato K, et al. Optimal starting time of acquisition and feasibility of complementary administration of

nitroglycerin with intravenous beta-blocker in multislice computed tomography. JCCT. 2009;33(2):193)

64. Chun EJ et al J. Effects of nitroglycerin on the diagnostic accuracy of electrocardiogram-gated coronary

computed tomography angiography. JCCT. 2008;32(1):86-92)

65. Wang G, Vannier MW. Spatial variation of section sensitivity profile in spiral computed tomography.

Medical physics. 1994;21(9):1491-7.

66. Ohnesorge B, Flohr T, Becker C, Kopp AF, Schoepf UJ, Baum U, et al. Cardiac imaging by means of

electrocardiographically gated multisection spiral CT: initial experience. Radiology. 2000;217(2):564-71.

67. Halliburton SS, Abbara S. Practical tips and tricks in cardiovascular computed tomography: patient

preparation for optimization of cardiovascular CT data acquisition. Journal of cardiovascular computed

tomography. 2007;1(1):62-5.

68. Bae KT, Tran HQ, Heiken JP. Multiphasic injection method for uniform prolonged vascular enhancement

at CT angiography: pharmacokinetic analysis and experimental porcine model. Radiology.

2000;216(3):872-80.

69. Fleischmann D, Rubin GD, Bankier AA, Hittmair K. Improved uniformity of aortic enhancement with

customized contrast medium injection protocols at CT angiography. Radiology. 2000;214(2):363-71.

70. Haage P, Schmitz-Rode T, Hubner D, Piroth W, Gunther RW. Reduction of contrast material dose and

artifacts by a saline flush using a double power injector in helical CT of the thorax. AJR American journal of

roentgenology. 2000;174(4):1049-53.

71. Hopper KD, Mosher TJ, Kasales CJ, TenHave TR, Tully DA, Weaver JS. Thoracic spiral CT: delivery of contrast

material pushed with injectable saline solution in a power injector. Radiology. 1997;205(1):269-71.

72. Raju R, Thompson AG, Lee K, Precious B, Yang TH, Berger A, et al. Reduced iodine load with CT coronary

angiography using dual-energy imaging: a prospective randomized trial compared with standard coronary

CT angiography. Journal of cardiovascular computed tomography. 2014;8(4):282-8.

73. Carrascosa P, Leipsic JA, Capunay C, Deviggiano A, Vallejos J, Goldsmit A, et al. Monochromatic

image reconstruction by dual energy imaging allows half iodine load computed tomography coronary

angiography. European journal of radiology. 2015.

74. Yin WH, Lu B, Gao JB, Li PL, Sun K, Wu ZF, et al. Effect of reduced x-ray tube voltage, low iodine

concentration contrast medium, and sinogram-affirmed iterative reconstruction on image quality and

radiation dose at coronary CT angiography: results of the prospective multicenter REALISE trial. Journal of

cardiovascular computed tomography. 2015;9(3):215-24.

75. Hein PA, May J, Rogalla P, Butler C, Hamm B, Lembcke A. Feasibility of contrast material volume reduction

in coronary artery imaging using 320-slice volume CT. European radiology. 2010;20(6):1337-43.

76. Kim R, et al. Feasibility of 320-row CT coronary angiography using 40 mL…Eur Radiol. 2016; Feb 23 (Epub

ahead of print).

HeartFlow, Inc.

| Acquisition and Reconstruction Techniques for Coronary CT Angiography: Canon Medical Systems Scanner Platforms

15991228 V2

77. Marwan et al Radiology High Pitch TAVR

78. Segal A, Ellis J, Baumgartner B, Choyke P, Cohan R, Costouros N, et al. ACR Committee on Drugs and

Contrast Media. Practice guideline for the use of intravascular contrast media. (Res. 38 - 2007) In: Practice

Guidelines and Technical Standards. Reston, VA: . American College of Radiology. 2008;73-78.

79. Brenner DJ, Doll R, Goodhead DT, Hall EJ, Land CE, Little JB, et al. Cancer risks attributable to low doses of

ionizing radiation: assessing what we really know. Proceedings of the National Academy of Sciences of the

United States of America. 2003;100(24):13761-6.

80. Committee to Assess Health Risks from Exposure to Low Levels of Ionizing Radiation; Nuclear and

Radiation Studies Board, Division on Earth and Life Studies, National Research Council of the National

Academies. Health Risks From Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2. Washington,

DC: The National Academies Press. 2006.

81. Don S. Radiosensitivity of children: potential for overexposure in CR and DR and magnitude of doses in

ordinary radiographic examinations. Pediatric radiology. 2004;34 Suppl 3:S167-72; discussion S234-41.

82. Einstein AJ, Henzlova MJ, Rajagopalan S. Estimating risk of cancer associated with radiation exposure

from 64-slice computed tomography coronary angiography. JAMA : the journal of the American Medical

Association. 2007;298(3):317-23.

83. Deseive S, Chen MY, Korosoglou G, Leipsic J, Martuscelli E, Carrascosa P, et al. Prospective Randomized

Trial on Radiation Dose Estimates of CT Angiography Applying Iterative Image Reconstruction: The

PROTECTION V Study. JACC Cardiovascular imaging. 2015;8(8):888-96.

84. Deseive S, Pugliese F, Meave A, Alexanderson E, Martinoff S, Hadamitzky M, et al. Image quality and

radiation dose of a prospectively electrocardiography-triggered high-pitch data acquisition strategy for

coronary CT angiography: The multicenter, randomized PROTECTION IV study. Journal of cardiovascular

computed tomography. 2015;9(4):278-85.

85. Hausleiter J, Martinoff S, Hadamitzky M, Martuscelli E, Pschierer I, Feuchtner GM, et al. Image quality

and radiation exposure with a low tube voltage protocol for coronary CT angiography results of the

PROTECTION II Trial. JACC Cardiovascular imaging. 2010;3(11):1113-23.

86. Hausleiter J, Meyer TS, Martuscelli E, Spagnolo P, Yamamoto H, Carrascosa P, et al. Image quality and

radiation exposure with prospectively ECG-triggered axial scanning for coronary CT angiography:

the multicenter, multivendor, randomized PROTECTION-III study. JACC Cardiovascular imaging.

2012;5(5):484-93.

87. Chen MY, et al. Submillisievert median radiation dose for coronary angiography with a second-generation

320-detector row CTscanner in 107 consecutive patients. Radiology. 2013 Apr;267(1):76-85. doi: 10.1148/

radiol.13122621. Epub 2013 Jan 22.

88. Zhao L, Plank F, Kummann M, Burghard P, Klauser A, Dichtl W, Feuchtner G. Improved non-calcified plaque

delineation on coronary CT angiography by sonogram-affirmed iterative reconstruction withdifferent filter

strength and relationship with BMI. Cardiovasc Diagn Ther. 2015 Apr;5(2):104-12.

HeartFlow, Inc.

| Acquisition and Reconstruction Techniques for Coronary CT Angiography: Canon Medical Systems Scanner Platforms

15991228 V2

89. Task Group on Control of Radiation Dose in Computed T. Managing patient dose in computed

tomography. A report of the International Commission on Radiological Protection. Annals of the ICRP.

2000;30(4):7-45.

90. Hausleiter J, Meyer T, Hadamitzky M, Huber E, Zankl M, Martinoff S, et al. Radiation dose estimates from

cardiac multislice computed tomography in daily practice: impact of different scanning protocols on

effective dose estimates. Circulation. 2006;113(10):1305-10.

91. Siegel MJ, Schmidt B, Bradley D, Suess C, Hildebolt C. Radiation dose and image quality in pediatric CT:

effect of technical factors and phantom size and shape. Radiology. 2004;233(2):515-22.

92. Leipsic J, LaBounty TM, Mancini GB, Heilbron B, Taylor C, Johnson MA, et al. A prospective randomized

controlled trial to assess the diagnostic performance of reduced tube voltage for coronary CT

angiography. AJR American journal of roentgenology. 2011;196(4):801-6.

93. Oda S, Utsunomiya D, Funama Y, Yonenaga K, Namimoto T, Nakaura T, et al. A hybrid iterative

reconstruction algorithm that improves the image quality of low-tube-voltage coronary CT angiography.

AJR American journal of roentgenology. 2012;198(5):1126-31.

94. Williams MC, Weir NW, Mirsadraee S, Millar F, Baird A, Minns F, et al. Iterative reconstruction and

individualized automatic tube current selection reduce radiation dose while maintaining image quality in

320-multidetector computed tomography coronary angiography. Clinical radiology. 2013;68(11):e570-7.

95. Deseive S, Pugliese F, Meave A, Alexanderson E, Martinoff S, Hadamitzky M, et al. Image quality and

radiation dose of a prospectively electrocardiography-triggered high-pitch data acquisition strategy for

coronary CT angiography: The multicenter, randomized PROTECTION IV study. Journal of cardiovascular

computed tomography. 2015;9(4):278-85.

This paper is presented as a service to medical personnel by HeartFlow and Canon Medical Systems. 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, medical advice. For any use, the product information guides, inserts, and operation manuals of the various CT acquisition

devices should 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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| Acquisition and Reconstruction Techniques for Coronary CT Angiography: Canon Medical Systems Scanner Platforms

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