Caption: Figure 4: [T.sub.1]-weighted MR phantom images of aqueous dispersion of samples (0.9 mg/mL) acquired at 1.5 T and RT with different inversion times
Importantly, having fixed the infrastructure and the signalling system, the minimum headway between two successive convoys depends on inversion times
and the main features of the signalling system, that is,
The engineers originally formulated the inversion constraint as: "if a duplex sheet is followed by a simplex sheet, the simplex sheet has to be fed with a delay that is equal to the inversion time
of the duplex sheet." Engineers found it useful to "compile" the system's expected behavior into a constraint between simplex and duplex sheets, simply because traditionally duplex sheets were always inverted while simplex sheets were not.
Fast FLAIR imaging incorporates inversion times
in the range of 2000 msec to 3000 msec to cancel the signal from cerebral spinal fluid (CSF).
Certain imaging parameters were held constant during the study for CSE, (field of view, 100A-100 mm; number of acquisition,1; slice thickness,4mm; percentage sampling, 100; pixel per mm resolution, 1.280), FLAIR(inversion time
, 860 ms; echo train length, 5) and FSE (echo train length, 7).
Viability is assessed in MRI by the delayed-enhancement sequence (DE-MRI), which typically is acquired 10 to 20 minutes after administration of gadolinium-chelate (0.1 to 0.2 mmol/kg), most commonly using a segmented k-space inversion-recovery gradient-echo pulse sequence, where the inversion time
is set to null signal from normal myocardium.
At 160 [degrees] C the inversion time
was nearly doubled, and at 140 [degrees] C the inversion took a significantly longer time (on the order of 75 min).
In the imaging of an infarct, it is possible to select an inversion time
following manganese administration whereby the infarct is nulled and the myocardium enhances, in an opposite fashion to DEMRI with gadolinium.