In-phase and opposed-phase MRI: what the signal drop means
A drop in signal on opposed-phase means fat and water in the same voxel. This is how it is read and what can fake it.
In-phase and opposed-phase (chemical shift)
Signal drops on opposed-phase where fat and water share a voxel. Signal drops on the in-phase image (longer TE) where iron is present.
Proves microscopic fat: liver steatosis, adrenal adenoma, fat-containing liver and kidney tumours. Detects iron overload.
TE must be correct for the field strength: about 2.2 and 4.4 ms at 1.5 T, about 1.1 and 2.2 ms at 3 T. Acquire before contrast.
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.