The Scatterplot Over Time report helps identify unusual patterns or outliers for DIR dose indices. You may elect to plot either the maximum or total dose index for CTDIvol, Dose Length Product (DLP), or Size-Specific Dose Estimate (SSDE).
To access the report, start by clicking CT Standardized Dose Index Reports from the Interactive Reports submenu, then click on the Scatterplot Over Time tab.
Select at least one Corporate Account and click Apply to create a scatterplot. By default, the report filters are set to retrieve exams for all facilities for the current month for all RPIDs and scanners.
Use the report filters and parameters to refine the data in the scatterplot:
Note: DIR statistics are available only for scatterplots when Query by is set to RPID because Study Descriptions are not standardized and cannot be aggregated and compared across DIR facilities.
Sample Scatterplot and Functionality
The following example illustrates different features and components of the scatterplot report using the following criteria:
DIR Measure: CTDIVol Max across Scans
Include Data from: This year
Exam Date Range: 01-Jan-19 to 26-Jul-19
Query by: RPID
RPIDs: CT ABD PELVIS W IVCON (RPID145)
Highlight: 75th Percentile
The report plots each value of CTDIvol, in mGy, by date. The Facility Exam Count table lists the number of exams, by age group, and the Registry Statistics table lists the corresponding number of studies, the median and the 75th percentile for the entire registry for the comparison time period. Because the Highlight parameter is set to 75th Percentile that statistic is highlighted on the chart, using data for the Adult (Over 18) age group because it has the most data of all age groups listed in the Facility Exam Counts table.
A total of 581 exams for the facility appear on the plot for two different scanners. The Scanner Statistics table summarizes the number of observations and minimum, maximum, and median measure values, with color coding to indicate the largest values within each column. The color coding highlights 15.1 as the largest median across all scanners. Clicking on that row highlights it in the table and filters the scatterplot to show only the data points for that scanner, making it easier to see which exams from that scanner are higher than the DIR statistic. To undo the filter, click on the highlighted row a second time, or click the Undo button, in the lower left corner.
Note: You can also highlight data by clicking on a scanner in the Scanner Legend.
Although the majority of exams are for adult patients, there are also a few pediatric exams, as indicated by the age group distribution. Using the Age Group filter, you can restrict the plot to a single pediatric age group, such 15 - 18y. Doing so also changes the highlighted registry statistic from 18.1 to 11.9, providing a more useful comparison for these data points. You can also click on the 15-18y group in the Facility Exam Count table, which then filters the scatterplot and updates the highlighted 75th percentile.