SAR limit reached: how to get the sequence to run
The scanner holds the sequence because the predicted RF heating is over the limit. This is what to change, in order.
SAR limit reached
Too much RF power per unit time for this patient: many 180° pulses, short TR, many slices, saturation bands, a wrong (too low) weight entry, or scanning at 3 T.
- Check the weight entered
- Reduce the refocusing flip angle, or choose the low-SAR RF option
- Lengthen TR or reduce slices, or split into two acquisitions
- Shorten the echo train or remove a saturation band
- Let the patient cool between sequences; consider a gradient-echo alternative
Never. Do not bypass the limit and do not enter a false weight.
This page is one entry from the MRI Technologist Reference
The full reference has 31 protocols, 9 dynamic study timelines, 19 artifacts, 16 scanner problems and 15 safety topics, as a PDF in English and Arabic plus an interactive tool.
Educational reference. It does not replace your site protocols, the radiologist's instructions, the MR safety officer, or the manufacturer's instructions for any implant, device or contrast agent. Parameter values are typical starting points at 1.5 T and must be adapted to the scanner, coil and patient.