CADTH Health Technology Review

Canadian Medical Imaging Inventory 2022–2023: Methods

CMII Report

Abbreviations

CMII

Canadian Medical Imaging Inventory

CT

computed tomography

FTE

full-time equivalent

MRI

magnetic resonance imaging

OECD

Organisation for Economic Co-operation and Development

PACS

picture archiving and communication system

PET

positron emission tomography

SPECT

single-photon emission computed tomography

The Canadian Medical Imaging Inventory

The Canadian Medical Imaging Inventory (CMII) was created in 2015 to track, compare, and map trends over time related to the availability, distribution, technical specifications, and use of advanced imaging equipment in Canada (i.e., computed tomography [CT], magnetic resonance imaging [MRI], positron emission tomography [PET]-CT, PET-MRI, single-photon emission computed tomography [SPECT], and SPECT-CT). This is the fourth iteration of the CMII since CADTH resumed the collection of this data in 2015. Previously, from 2003 to 2012, the Canadian Institute for Health Information (CIHI) collected data on medical imaging technologies in Canada.

The CMII collects data through a survey conducted approximately once every 2 years and details the use of strategies for improving appropriate imaging, enhancing system efficiencies, reducing wait lists, and addressing other systemic challenges.

Robust data are required to ensure health systems can deliver the imaging required to provide timely, safe, patient-centred care; improve health outcomes; and deliver health care efficiencies. The data collected by the CMII can be used by decision-makers for the following purposes:

Methodology and Analysis

Data about CT, MRI, PET-CT, PET-MRI, SPECT, and SPECT-CT availability and use were primarily collected via a web-based survey. Both English- and French-language versions were offered.

The 2022–2023 survey was based on the 2019–2020 iteration of the survey,1 with the following change:

The survey respondents who had participated in previous iterations of the inventory1-3 were presented with prepopulated forms for updating and completion. The respondents for new sites were identified by jurisdiction validators and other imaging professionals and were provided with blank forms.

Prepopulation data were obtained from the following sources:

Sites with name changes were updated and verified via web searches and/or by contacting the facility directly. Data for sites that were identified as being closed (by web search or respondent or validator communication) were archived.

The site-level data collected consisted of the availability of each modality, as well as, for each modality:

Site-level data also included the type of facility, the use of picture archiving and communication system (PACS), and the proportions of funding received from different sources (e.g., public, private).

The unit-level information collected consisted of, for each unit:

The 2022–2023 survey respondents were asked to update the available data to reflect the status as of the time of their survey response. If they did not update the survey, it was assumed that no changes had been made from the 2019–2020 survey.1

Jurisdiction Validators

Senior medical imaging decision-makers within health ministries and/or regional health authority located in each province and territory were consulted to validate unit and exam counts for consistency. These validator-reported unit counts and examinations in the last fiscal year were preferentially used over survey data. Validator data were also used to calculate unit counts per population and exams per population.

Validators at times reported equipment dates that differed slightly from those documented the 2022–2023 CMII report. This often depended on the availability of regional- or provincial-level data at the time of reporting or for specific reporting periods. The site-level unit counts supplied by validators were used to identify missing or surplus units in the database.

Validators were also requested to identify:

In some instances, validators also updated this provincial and/or regional data up until October 31, 2023.

Identification of Potential Respondents

Most respondents were identified in advance from a database of previous participants. These contacts were updated to account for changes due to position turnover, retirement, or restructuring.

Potential respondents included:

Some respondents were identified through validators, external collaborators, and participant referrals. Respondents for new private facilities were identified by cross-referencing provincial documents, conducting web searches, and contacting facilities directly.

Passive methods of recruitment included promoting the renewed survey on the CADTH website and by word of mouth.

To access the survey, all participants were asked to register a profile on an external website to ensure their response was linked to a unique registration profile. Registrants were matched to sites if there was a preexisting record or, if there was no preexisting record, were presented with a blank form to create a new record.

Duration of Survey

The survey opened on May 15, 2023, and data collection from survey respondents and validators was closed on October 31, 2023.

Data Validation

Once initial data collection from the survey was complete, we created summary statistics of the number of units per modality in each jurisdiction. The summary statistics were reviewed by the identified validators. Depending on the jurisdiction, each validator reviewed data for an entire province or territory, or for 1 or more health regions within a province. The validators assessed the summaries for accuracy and provided corrections and information on nonrespondents (e.g., unit counts or examinations, either at a site or jurisdictional level). The validators were also asked to encourage no-respondents in their regions to participate in the survey.

The validators provided unit counts and examination volume data for their jurisdiction (i.e., province or region). They were also given an early draft of the 2022–2023 CMII overview report and modality-specific reports to confirm the main findings. In some instances, validators adjusted site-level data.

Data Analysis

The data sources used in the CMII, with the exception of the survey and validator responses, are presented in Table 1. Use of the datasets in the analysis are presented in Table 2.

Table 1: Additional Data Sources Used in the CMII

Data source

Application of data

Canadian population data and projections

We obtained population data and projections for Canada and the provinces from Statistics Canada.4

International comparison data

We obtained international comparison data for the number of units and examinations for CT, MRI, and PET from the OECD website.5-9

CMII = Canadian Medical Imaging Inventory; OECD = Organisation for Economic Co-operation and Development.

Table 2: Use of Datasets in Analyses

Data summaries

Data sources

CMII 2022–2023 survey

CMII 2019–2020 survey

CMII 2017 surveya,b

CIHI 2012 datac

Validatior datad

Statistics Canadae

International dataf

Other sourcesg

Summaries of site characteristics

x

x

x

Summaries of modality availability and number of units

x

x

x

x

Summary of planned installations and planned decommissioning

x

x

Summary of units at sites that had responses to the 2015 survey but no responses or validation data for the 2017 surveya

x

Maps of machine locations

x

Summaries of exams in 1 fiscal year

x

x

x

x

x

Summaries of average hours per week and hours per day of operation; summaries of proportions of types of use

x

x

x

Summaries of units per site and units per population

x

x

Comparisons of inventory with international availability for CT, MRI, and PET-CT

x

x

Age of units, current and decommissioned

x

x

x

x

Technical specifications of current units

x

x

x

x

Equipment decision-making considerations (e.g., funding source, equipment procurement, and expansion)

x

Summaries related to health human resources and wait times

X

x

x

x

x

CIHI = Canadian Institute for Health Information; CMII = Canadian Medical Imaging Inventory; CT = computed tomography; MRI = magnetic resonance imaging; OECD = Organisation for Economic Co-operation and Development; PET = positron emission tomography; x = data source used.

aSites that had a response to the 2015 survey, but not the 2017 survey, identified by the lack of a submission form for the 2017 survey or of correspondence indicating no change or describing changes.

bThese data included responses from site survey responses (supplemented by data validators) and a supplementary grey literature search conducted for the 2015 report.2

cFrom the dataset originally supplied to CADTH by CIHI, consisting of data collected between 2003 and 2012, as described in the 2015 CMII report.2

dData were supplied by jurisdictional validators.

eInternational data from the OECD.5-9

fPopulation data from Statistics Canada.4,10

gData were sourced from literature searches, research and professional organizations, and personal correspondence.

Data Summaries

We present the data using descriptive summaries and graphs of site-level and jurisdiction-level findings. We use counts for discrete data, such as the number of sites with a given modality or the number of units at a site. Continuous values are presented either as summary statistics (e.g., mean [average], median, or range between minimum and maximum values) or as assigned categories (e.g., hours of use per day as less than 8 hours, 8 to less than 12 hours, 12 to less than 18 hours, and 18 hours or more). Where we asked respondents to choose between 2 or more responses (e.g., yes or no), we report the counts and/or percentages of respondents who selected each response. Stacked bar charts were used to display the number of units and hours and percentage of use as categories. The geographical distribution of modalities was presented on maps using geocoded data.

International Comparison

The total or per capita number of units and exams of 3 imaging modalities — CT, MRI, and PET — from Organisation for Economic Co-operation and Development (OECD) countries was plotted with the data from the CMII 2022–2023 survey. Canada’s ranking among OECD countries was reported.

Future Projections of the Numbers of Units and Exams for Canadian Provinces and Territories

The number of units and exams in Canada was projected for the years 2025, 2030, 2035, and 2040 based on the per capita values in 2022–2023 and estimated population growth provided by Statistics Canada.10 Three different population scenarios were envisioned for low, medium, and high projected growth. Median units and exams were projected based on median growth and upper and lower limits were based on the high- and low-growth assumptions.

The projections calculations used the current per capita number of units and exams volumes for 2022–2023 and assumed that these values remained unchanged over the forested period.11 The projections are based on jurisdiction-wide population data and did not reflect projected growth in specific areas within a jurisdiction. This simplified assumption was similar to the 1 made by the Conference Board of Canada.11

Missing Data and Imputation

Handling of Data From Sites Without Updated Data in 2022–2023

If the 2022–2023 survey was not updated for a site, we assumed there was no change from the 2019–2020 data. We carried forward data from previous surveys according to the following rules:

Imputing Missing Data

References

1.Chao Y-S, Sinclair A, Morrison A, Hafizi D, Pyke L. The Canadian Medical Imaging Inventory 2019-2020. Ottawa: CADTH; 2021: https://www.cadth.ca/sites/default/files/ou-tr/op0546-cmii3-final-report.pdf. Accessed 2024 Jan 10.

2.Sinclair A, Quay T, Pyke L, Morrison A. The Canadian Medical Imaging Inventory 2015. Ottawa: CADTH; 2016: https://www.cadth.ca/sites/default/files/pdf/canadian_medical_imaging_inventory_2015_e.pdf. Accessed 2024 Jan 10.

3.Sinclair A, Morrison A, Young C, Pyke L. Canadian Medical Imaging Inventory, 2017. Ottawa: CADTH; 2018: https://www.cadth.ca/sites/default/files/pdf/canadian_medical_imaging_inventory_2017.pdf. Accessed 2024 Jan 10.

4.Statistics Canada. Canada's population estimates, first quarter 2023. The Daily. Ottawa (ON): Government of Canada; 2023: https://www150.statcan.gc.ca/n1/daily-quotidien/230628/dq230628c-eng.htm. Accessed 2024 Jan 5.

5.Organisation for Economic Co-Operation and Development. Computed tomography (CT) scanners https://data.oecd.org/healtheqt/computed-tomography-ct-scanners.htm. Accessed 2023 Nov 9.

6.Organisation for Economic Co-Operation and Development. Magnetic resonance imaging (MRI) units. https://data.oecd.org/healtheqt/magnetic-resonance-imaging-mri-units.htm#indicator-chart. Accessed 2023 Nov 9.

7.Organisation for Economic Co-Operation and Development. Positron emission tomography (PET) scanners and exams. https://stats.oecd.org/ Accessed 2023 Nov 9.

8.Organisation for Economic Co-Operation and Development. Computed tomography (CT) exams. 2023; https://data.oecd.org/healthcare/computed-tomography-ct-exams.htm. Accessed 2023 Nov 9.

9.Organisation for Economic Co-Operation and Development. Magnetic resonance imaging (MRI) exams. 2023; https://data.oecd.org/healthcare/magnetic-resonance-imaging-mri-exams.htm#indicator-chart. Accessed 2023 Nov 9.

10.Canada S. Population Projections for Canada (2021 to 2068), Provinces and Territories (2021 to 2043): Technical Report on Methodology and Assumptions. 2023.

11.The value of radiology, part II. Ottawa: The Conference Board of Canada; 2019: https://car.ca/wp-content/uploads/2019/07/value-of-radiology-part-2-en.pdf. Accessed 2020 Sep 30.

Appendix 1: Survey Questions for the 2022–2023 CMII Survey

Site and Facility Information

Picture Archiving and Communication System (PACS)

Machine Types

CT

CT: Make and Model

CT: Individual Unit Specifications

MRI

MRI: Make and Model

MRI: Individual unit specifications

MRI: Fixed/Mobile

MRI: Portable

PET or PET-CT

PET or PET-CT: Make and Model

PET or PET-CT: Individual Unit Specifications

PET or PET-CT: Usage

SPECT

SPECT: Make and Model

SPECT: Individual Unit Specifications

SPECT-CT

SPECT-CT: Make and Model

SPECT-CT: Individual Unit Specifications

PET-MRI

PET-MRI: Make and Model

PET-MRI: Individual Unit Specifications

All Modalities

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI

This applies to: CT, MRI, PET or PET-CT, SPECT, SPECT-CT, PET-MRI