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 current month 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 current month, to date.

    • Exam Date Range 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

  • Highlight selects comparison statistics for the entire registry to display on the graph, using data for the age group with the most exams, as listed in the Facility Exam Count table. Registry statistics are not highlighted in the boxplot chart 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

    • There are too few exams or facilities for the entire registry (fewer than 100 exams or 10 facilities) for the RPID and age group

    • 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

  • Include Data From: Previous year (1/1/2018 to 12/31/2018)

  • Exam Date Range: January 1 – March 31, 2018

  • Query by: RPID

  • RPID: CT HEAD BRN WO IVCON (RPID266)

  • Highlight: 75th Percentile

DIR Interactive Reports - Sample Boxplot by Scanner 1


The report shows boxplots for each of the scanners meeting the filter criteria. The Facility Exam Count table lists the number of exams, by age group, and the Registry Statistics table shows the comparison statistics for the entire DIR. The Scanner Statistics table shows the number of exams and minimum, maximum and median 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 may provide 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 often varies by patient size, we can also further restrict the data by age group to identify any outliers. For example, we can select the 0 - 2y age group using the Age Group filter or by clicking on the 0 - 2y row in the Facility Exam Count table.

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 a few 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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