The Boxplot by Scanner report compares data between scanners within a single facility or across multiple facilities.

You can access the report by selecting CT Standardized Dose Index Reports from the Interactive Reports menu, and then clicking the Boxplot by Scanner tab. 

Select at least one Corporate Account and click Apply to generate the boxplot. By default, the report filters are set to retrieve exams for all facilities with study dates occurring within the past seven days for all RPIDs and scanners.

Use the report filters and parameters to refine the data in the chart:

  • DIR Measure selects the Dose index type (CTDIvol, DLP, or SSDE) to be displayed using either the maximum value across scans or total for the exam

Note: Maximum and total values are equal for single-scan exams

  • There are two separate filters for study dates

    • Include Data From specifies the time period to include, relative to today. The default is the past seven days

    • Exam Date displays the range of exam dates actually available and can be used to narrow the time frame to a range within the Include Data From time period

  • Age Group

  • Query by determines whether the RPID / Study description filter displays standardized RPID exam names or the facility’s Study Descriptions

  • Body Part restricts the RPID / Study filter to exams for the specified body part(s)

  • RPID / Study Description lists the available RPIDs or Study Descriptions, as determined by the Query by parameter setting

  • Scanner

  • Registry Statistics selects comparison statistics for the entire registry to display on the graph. Only data for the oldest age group are used. Registry statistics are not highlighted in the following cases

    • No registry benchmarks are available for the selected RPID

    • More than one RPID is selected in the RPID / Study Description filter

    • The Query by parameter is set to Study Description

Note: DIR statistics are available only when Query by is set to RPID because Study Descriptions are not standardized and cannot be aggregated across DIR facilities.

  • Scanner Aggregation Level determines whether to aggregate scanner data in the chart by device name, model, or manufacturer

The following example shows the distribution of measures by scanner for brain CTs, without contrast, in the first three months of 2018, using the following criteria:
  • DIR Measure: CTDIvol Max across scans

  • Age Group: All

  • Date Range: January 1 – March 31, 2018

  • Scanners: All

  • Query by: RPID


  • Registry Statistics: 75th Percentile

DIR Interactive Reports - Sample Boxplot by Scanner 1

The report shows boxplots for each of the scanners meeting the filter criteria. The Registry Statistics table shows the DIR medians and 75th percentiles for the entire registry, by age group, as well as the facility exam counts. The Scanner Statistics table shows the number of exams and minimum, maximum and mean values for the selected measure. Scanner statistics are color coded in red indicating the largest values within each column.

Changing the Scanner Aggregation parameter from Device to Model provides a more useful comparison by aggregating data to the model level, as different scanner models may require different dose levels to obtain the same quality diagnostic image.

DIR Interactive Reports - Sample Boxplot by Scanner 2

Because dosage varies by size, we can also further restrict the data to age group 0-2 to identify any outliers.

DIR Interactive Reports - Sample Boxplot by Scanner 3

In the above example, one scanner model appears to be an outlier for the age group and exam compared to the DIR 75th percentile, although this based on only three data points. Additional information is available for each plotted data point by hovering over it with the cursor.

DIR Interactive Reports - Sample Boxplot by Scanner 4

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