CINE SEQUENCE

What are cine Sequences?

Cine sequences are used for the assessment of cardiac function. During cine acquisition several individual images are acquired in different phases of the cardiac cycle. These are then played as a movie to provide the user with a ‘video’ of the cardiac activity.

TrueFISP sequences are highly recommended for cine imaging due to high temporal and spatial resolution and improved blood- tissue contrast. For cardiac cine imaging TrueFISP is used in combination with i-pat technology to reduce the acquisition time

Steady-state free precession (SSFP) imaging is a magnetic resonance imaging (MRI) sequence which uses steady states of magnetizations. In general, SSFP MRI sequences are based on a (low flip angle) gradient echo MRI sequence with a short repetition time which in its generic form has been described as the FLASH MRI technique. While spoiled gradient-echo sequences refer to a steady state of the longitudinal magnetization only, SSFP gradient-echo sequences include transverse coherences (magnetizations) from overlapping multi-order spin echoes and stimulated echoes. This is usually accomplished by refocusing the phase-encoding gradient in each repetition interval in order to keep the phase integral (or gradient moment) constant. Fully balanced SSFP MRI sequences achieve a phase of zero by refocusing all imaging gradients..

Steady-state free precession MRI (SSFP) is a type of gradient echo MRI pulse sequence in which a steady, residual transverse magnetisation (Mxy) is maintained between successive cycles. The sequence is noted for its superiority in dynamic/cine assessment of cardiac function.

Types of image formed

At steady state, two signal types are present:

T1/T2* weighted: the mixed steady-state signal - subjected to refocusing gradient; this generates the FID (typical of a GRE sequence)
T2 weighted: the residual Mxy at the beginning of the next pulse; the α flip (50°-80° in typical GRE) results in spin-echo (analogous to the 180° refocusing pulse used in spin-echo)

Applications