tic_analyse: Plot and analyse time-intensity data

In tican: Plot and Analyse Time-Intensity Data

Plot and analyse time-intensity data

Description

This function plots and analyzes time-intensity data, such as data from (contrast-enhanced) ultrasound cineloops. Peak intensity and time to peak intensity are calculated from a smoothed curve through the data (loess smoother). Area under the curve is calculated from the raw data using the trapezium method for integration. Time to peak proportion (for example time to 90 percent of peak) can also be calculated.

Usage

tic_analyse(
  data,
  timevar,
  intensityvar,
  loess.span = 0.1,
  AUCmax = NULL,
  peakproportion = NULL,
  plotresult = TRUE,
  ...
)

Arguments

data	A dataframe with time and intensity values as columns.
timevar	A character string (in quotes) with the dataframe column name for the time variable.
intensityvar	A character string (in quotes) with dataframe column name for the intensity variable.
loess.span	A number between 0 and 1, with larger values resulting in a smoother curve.
AUCmax	A number - the maximum time that area under the curve is measured until.
peakproportion	A number between 0 and 1 which is used in the time to peak proportion calculations.
plotresult	TRUE or FALSE to determine whether a plot of the results is generated.
...	Additional arguments to be passed into the loess() function.

Details

A plot of the data is generated and a dataframe with the results is returned.

Value

A dataframe with the results. Depending on the plotresult argument can also return a plot of the smoothed curve.

Examples

# Example usage:

# Generating simulated data
set.seed(123)
example_data <- data.frame(time = seq(0, 82, by = 0.25))
random_vals <- sample(1:10, nrow(example_data), replace = TRUE)
example_data$regionA_intensity <- log(example_data$time + 1) * 50 -
  example_data$time * 2 + random_vals
example_data$regionB_intensity <- log(example_data$time + 7, base = 10) *
  80 - example_data$time * 1.5 + random_vals

# Example with defaults:

tic_analyse(data = example_data, timevar = "time", intensityvar = "regionA_intensity")

# Example with additional arguments:

tic_analyse(data = example_data, timevar = "time", intensityvar = "regionA_intensity",
                  loess.span = 0.1, AUCmax = 30, peakproportion = 0.9, plotresult = TRUE)

tican documentation built on June 8, 2025, 11:05 a.m.