Magnetic resonance imaging is the medical imaging modality with by far the largest diversity of “imaging modes” (aka MR sequences) and additional parametrization for each of it. Even more, preparation and data acquisition of MR signal are - though interrelated – independent most of the time. There seems to be the habit in the MR community to compete in terms of fantasy when it comes to sequence naming. Over the past, this has led to a huge variety of different acronym denoting MR sequence, which are closely related, but still carry different names. Very minor changes seem to justify the creation of new acronyms. This makes the field of MR sequences challenging. Fortunately, dictionaries of acronyms exist to guide one through this jungle (for links see reference section). To make things worse, vendors are using different names and brands for MR sequences, which have the same physical basis. The main reasons for this are sometimes historic, but most of the time patent law considerations and the wish for unique selling propositions are more relevant. There are very little MR sequences, which carry the same name at all of the larger companies. “SE” for spin echo imaging and EPI for echo planar imaging are glorious exceptions, but even for the acquisition of multiple spin echoes, vendors will use different names (like turbo spin echo (TSE) or fast spin echo (FSE)). If all lines are acquired in a single echo train (‘single-shot’), again, new names are created (single-shot FSE or TSE, HASTE, FASE). The are some commonalities like utilizing 2D/3D is some sequence names to label sequence with either one or two phase-encoding directions, however, after image reconstruction this distinction vanishes and a 3D image dataset is present. This can pose problems when interpreting certain image artifacts, which will behave differently for 2D multi-slice and 3D. This is even further enhanced by the fact that there is no clear definition of what contiguous slices mean (Is there a gap? How is the gap defined? How is the point-spread-function of the excitation pulse taken into account? …), which differs from vendor to vendor. Not only sequence names differ, parameter and option names will differ from vendor to vendor. In rare case, parameter will have the same name but have a rather different unit. Thus, care has to be taken when converting protocols across vendors. Also, when comparing scanner specifications, there are vendor specific habits how this data is presented. Sometimes different units are used for magnetic flux density (Tesla, Gauss) and derived parameters like gradient strength. 10,000 Gauss equal 1 Tesla, so for gradient performance, the max amplitude is often given in either mT/m or in G/cm (100 G/cm = 1000 mT/m = 1 T/m. MR sequence naming schemes across vendors are rather far from logical and easy to grasp (although typically consistent in each domain). The ideal way when dealing with standardization in cross-vendor studies or setups is the use of MR acronym guides, which can be found in the internet. Some useful links are provided in the reference section.

Acknowledgements

No acknowledgement found.