logan_analysis#

petpal.kinetic_modeling.graphical_analysis.logan_analysis(tac_times_in_minutes: numpy.ndarray, input_tac_values: numpy.ndarray, region_tac_values: numpy.ndarray, t_thresh_in_minutes: float) → numpy.ndarray#

Performs Logan analysis on given input TAC, regional TAC, times and threshold, considering non-zero values.

This function is similar to logan_analysis_with_rsquared(), but avoids the issue of division by zero by only considering non-zero TAC values for the region TAC since it is in the denominator. If the number of non-zero indices is less than or equal to 2, or if the number of time points after the threshold is less than or equal to 2, the function returns an array of NaNs.

Parameters:

  • tac_times_in_minutes (np.ndarray) – Array of times in minutes.

  • input_tac_values (np.ndarray) – Array of input TAC values.

  • region_tac_values (np.ndarray) – Array of ROI TAC values.

  • t_thresh_in_minutes (np.ndarray) – Threshold time in minutes. Line is fit for all values after the threshold.

Returns:

np.ndarray –

Array of two elements - (slope, intercept) of the best-fit line to the given

data.

Important

  • The interpretation of the returned values depends on the underlying kinetic model.

  • We assume that the input TAC and ROI TAC values are sampled at the same times.

On this page

This Page