Protocol - Chest Computed Tomography (CT)

Description

Chest computed tomography (CT) is a non-invasive test that shows the size, shape, and structure of the lungs and other structures in the thorax. The chest CT scanning machine takes many pictures, called slices, of the lungs and the inside of the chest. A computer processes these pictures to be viewed on a monitor or printed on film. The computer can also stack the pictures to create a detailed, three-dimensional (3D) model of the organs. This 3D digital information can be used to measure the dimensions of the structure, such as the bronchial tree, or the density of the structure, such as the lung parenchyma. It is important that the CT scanner used in any clinical research study be calibrated regularly against calibration standards that are provided by the manufacturer or in some instances by the study itself.

Specific Instructions

Risks of CT Scan: CT scans are acquired using ionizing radiation. Exposure to ionizing radiation may cause some increase in risk of cancer. The precise level of risk is not known, but appears relatively small. For example, in a 57-year-old female smoker, the estimated lung cancer risk from the radiation from a COPD CT scan is about 0.05%, or 1 in 2,000. Nonetheless, it is important to minimize any risk. Because CT may be associated with a small increased risk of cancer, CT should be performed only where this risk is outweighed by potential clinical benefit, or in the context of an approved research study. The CT scans should be performed with the lowest possible radiation exposure (http://www.copdgene.org/imaging).

Availability

Available

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Protocol

A. Subject Preparation for CT Scan

1. Prior to the study, the subject’s identity will be confirmed according to institutional policy.

2. The subject will remove all metallic devices from the chest area.

3. The subject will be informed of the importance of compliance with the breathing instructions. Ability to comply with instructions should be assessed, and conditions that might impair compliance such as deafness, breathlessness, or mental impairment should be noted.

4. At least one rehearsal of the end-inspiratory breath-hold should be performed.

B. CT Acquisition

All CT scans will be obtained using the protocol and breathing instructions as indicated. Scans must be reconstructed using two algorithms, edge enhancing and smooth. Contiguous end-expiratory CT images will also be obtained where possible.

Instructions for CT Scan Acquisition

GENERAL: This study consists of two scouts (topograms) and two scans. All scans use the same parameter grid.

CONTRAST: Oral/IV. None.

SUPINE INSPIRATION: Start at bottom of lungs, end at top of lungs. Instruct the patient to breathe as follows:

"For the first part of this study you will be asked to hold your breath for about 10 seconds. If you cannot hold your breath that long, try the best you can and then take very shallow, slow breaths if you need to."

"For now, take several easy, deep breaths and relax while we prepare to take a CT scan of your lungs."

Allow patient to breathe and relax for at least 15 seconds.

"I am now going to give you specific breathing instructions. Try to follow as best you can."

"Take in a deep breath....and let it out."

"Take in another deep breath....and let it out."

"Take in another deep breath, and hold your breath in. Keep holding your breath!"

Scan the patient in one breath-hold at full-inspiration.

When the scan is completed, tell the study participant to "Breathe and relax!"

SUPINE EXPIRATION: Same protocol as SUPINE INSPIRATION. Start at bottom of lungs, end at top of lungs. Instruct the patient to breathe as follows:

"For the second part of this study you will be asked to blow out your breath and hold it out for about 10 seconds. This is usually more difficult than holding your breath in, but do the best that you can. If you cannot hold your breath out that long, take a very slow shallow breath in if you need to."

"For now, take several easy, deep breaths and relax while we prepare to take the last CT scan of your lungs."

Allow patient to breathe and relax for at least 15 seconds.

"I am now going to give you more specific breathing instructions. Try to follow as best you can. "

"Take in a deep breath....and let it out."

"Take in another deep breath....and let it out."

"Take in another deep breath, let it out, and hold your breath out! Do not breathe!"

Scan the patient in one breath-hold at expiration as quickly as possible.

When the scan is completed, tell the study participant to "Breathe and relax!"

Personnel and Training Required

A trained radiologic technologist

Equipment Needs

The equipment necessary is an MDCT scanner. These are usually in the radiology departments of any major hospital. General Electric® (GE), Philips®, Siemens®, and Toshiba® all make MDCT scanners, which cost around $2 million; the room that the scanner is contained in generally costs around $1 million to build because of the need for lead shielding. Therefore, clinical study scans are usually performed under subcontract to a radiology department at a hospital or clinic or through a study radiologist with access to an MDCT machine. If computerized image segmentation processing and analysis is to be performed, this will require a separate computer workstation, usually a PC, with the image sets from the MDCT scanner being transferred to the computer workstation by direct computer link or through burning DVDs.

General Electric® is a registered trademark of the General Electric Company.

Philips® is a registered trademark of Koninklijke Philips Electronics N.V.

Siemens® is a registered trademark of Siemens Healthcare.

Toshiba® is a registered trademark of Toshiba Corporation.

Requirements

Requirement Category	Required
Major equipment	Yes
Specialized training	Yes
Specialized requirements for biospecimen collection	No
Average time of greater than 15 minutes in an unaffected individual	Yes

Mode of Administration

Noninvasive radiologic assessment

Lifestage

Adult, Senior

Participants

Age 18 or older

Selection Rationale

The recommended protocol is taken from the COPDGene Study. This is a multi-center National Institutes of Health-funded study that examines genome-wide association studies (GWAS) in human subjects with chronic obstructive pulmonary disease (COPD) and is using MDCT scanning to define the phenotype of these subjects. The protocol for undertaking MDCT scanning in clinical trials is changing as the MDCT scanners become more technologically advanced. Effectively, the protocol used should balance the radiation exposure from the MDCT scan against the information that the MDCT scan is expected to provide. In general, the lowest radiation dose to achieve the objectives of the study is what is required. As the radiation dose increases, the image clarity is also better, whereas in low radiation doses, the image may not be as clear (so-called "noise"). The suggested protocols for the major manufactures are described in section 15h of the Genetic Epidemiology of COPD Clinical Center Manual of Procedures Phase 2 Study Visits, Version 7.4, December 3, 2014.

Language

English

Standards

Standard	Name	ID	Source
Human Phenotype Ontology	Abnormality of the chest	HP:0000765	HPO
caDSR Form	PhenX PX090402 - Chest Computed Tomography Ct	6872325	caDSR Form

Derived Variables

None

Process and Review

The Expert Review Panel #6 (ERP 6) reviewed the measures in the Respiratory domain.

Guidance from ERP 6 includes:

• Updated protocol

Not back-compatible: requires changes to Data Dictionary

Previous version in Toolkit archive (link).

Protocol Name from Source

Genetic Epidemiology of COPD Clinical Center Manual of Procedures, 2014

Source

National Institutes of Health (NIH). (2014, December). Genetic Epidemiology of COPD Clinical Center Manual of Procedures Phase 2 Study Visits, section 15 (version 7.4). Retrieved from http://www.copdgene.org/sites/default/files/COPDGene_MOP_7.4_120314.pdf

General References

Regan, E. A., Hokanson, J. E., Murphy, J. R., Make, B., Lynch, D. A., Beaty, T. H., … Crapo, J. D. (2011). Genetic Epidemiology of COPD (COPDGene) study design. COPD: Journal of Chronic Obstructive Pulmonary Disease, 7(1), 32-43.

Protocol ID

90402

Variables

Export Variables

Variable Name	Variable ID	Variable Description	dbGaP Mapping
PX90402_Chest_Computed_Tomography_Scan_Algorithms
	PX090402050000	Were scans reconstructed using the edge more enhancing and smooth algorithms? show less	N/A
PX90402_Chest_Computed_Tomography_Scan_Contiguous_Expiratory_CT_Images
	PX090402060000	Were contiguous end-expiratory CT images obtained?	N/A
PX90402_Chest_Computed_Tomography_Subject_Identity
	PX090402010000	Has the subject's identity been confirmed?	N/A
PX90402_Chest_Computed_Tomography_Subject_Informed_Compliance_Instructions
	PX090402030000	Has the subject been informed of the more importance of compliance with the breathing instructions? show less	N/A
PX90402_Chest_Computed_Tomography_Subject_Rehearsal_Breath_Hold
	PX090402040000	Was at least one rehearsal of the more end-inspiratory breath-hold performed? show less	N/A
PX90402_Chest_Computed_Tomography_Subject_Remove_Metal_Devices
	PX090402020000	Has the subject removed all metallic devices more from the chest area? show less	N/A
PX90402_Chest_Computed_Tomography_Supine_Expiration_Breath_Hold
	PX090402100000	Was the scan taken during one breath-hold at more expiration as quickly as possible? show less	N/A
PX90402_Chest_Computed_Tomography_Supine_Expiration_Preparation
	PX090402090000	Was the subject allowed to breathe and relax more for at least 15 seconds while preparing to take a CT scan of the lungs? show less	N/A
PX90402_Chest_Computed_Tomography_Supine_Inspiration_Breath_Hold
	PX090402080000	Was the scan taken during one breath-hold at more full-inspiration show less	N/A
PX90402_Chest_Computed_Tomography_Supine_Inspiration_Preparation
	PX090402070000	Was the subject allowed to breathe and relax more for at least 15 seconds while preparing to take a CT scan of the lungs? show less	N/A

Respiratory

Measure Name

Chest Computed Tomography (CT)

Release Date

November 28, 2017

Definition

Chest computed tomography (CT) is a painless, non-invasive test that creates precise images of the structures in the chest, such as the lungs.

Purpose

The purpose of multi-detector computerized tomography (MDCT) scanning for research purposes relating to the thorax is generally to provide anatomical images. This structural assessment is an accurate depiction of the lungs and their components, including airways, lung parenchyma, and lung vasculature. The heart is also imaged when the lung images are acquired. At times, heart images can also be informative in the clinical research subject with lung problems.

Keywords

Respiratory, chest, CT scan, multi-detector computerized tomography, MDCT, COPDGene Study

Measure Protocols

Protocol ID	Protocol Name
90402	Chest Computed Tomography (CT)

Publications

There are no publications listed for this protocol.