MRI pulse sequences

Last revised by Elmira Hassanzadeh on 29 Nov 2021

An MRI pulse sequence is a programmed set of changing magnetic gradients. Each sequence will have a number of parameters, and multiple sequences grouped together into an MRI protocol. 

A pulse sequence is generally defined by multiple parameters, including:

Different combinations of these parameters affect tissue contrast and spatial resolution.

Parameters are discussed more fully in a separate article: MRI parameters.

MRI sequences can be grouped in a number of ways. Probably most accurately they are grouped according to the type of sequence (e.g. spin echo, or inversion recovery etc..) however for non radiologists another way of grouping sequences is by general image weighting (e.g. T1 or T2) and additional features (e.g. fat suppressed or gadolinium enhanced). This simplified approach is described in a separate article: MRI sequences (basic)

Pulse sequences can be broadly grouped as follows:

Multiple sequences are usually needed to adequately evaluate a tissue, and the combination of sequences is referred to as a MRI protocol. The radiologist tailors the pulse sequences to try to best answer the clinical question posed by referring physician.

Protocols are discussed more fully in a separate article: MRI protocols.

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