mono_t2 model does not output or plot Offset value if options.OffsetTerm = true

[gabuzi]

If I use the mono_t2 model to fit t2 maps and use the OffsetTerm in the model, the results do not contain any information about the OffsetTerm.

This leads to inconsistencies. For example, using plotModel with data where there may be a significant offset present, there is a systematic discrepancy between data and fit. Neither FitResults nor equation() do consider the offset.

Expected Behavior

If OffsetTerm is used in mono_t2, it should propagate to the fit results and be considered in the plot.

Actual Behavior

• the value of the offset term is not present in the fit results struct
• the equation() function does not consider the offset term either and returns the equation without offset, which is equivalent to offset = 0
• plotModel() also does not consider the offset, such that the behavior is as if offset = 0

Steps to Reproduce the Problem

1. acquire T2 data at low SNR
2. use mono_t2 with OffsetTerm enabled
3. look at FitResults: no offset value present. use plotModel(). the offset is not considered in the plot.

Specifications

• Version: 2.4.2
• Platform: windows with matlab 2023b
• Subsystem: ?