2017 Imaging for Physicists Coursebook

Compliance Levels

Compliance Levels

Parameter

Parameter

Dynamic series

TE Acceptable

TR Acceptable

2.0-2.5ms 1.5-2.0ms

5-7ms 3-5ms < 3ms

Target

Target

Ideal

<1.5ms

Ideal

Temporal resolution: The temporal resolution should be less than 10 sec. Flip angles: Smaller flip angles will lead to potential saturation of the signal intensity vs. gadolinium concentration, particularly in vessels. Note should be made that SAR limits may affect the maximum allowable flip angle. Operators should use the maximal allowed flip angle when SAR limitations occur. Flip angles ranging from 25-35 degrees are recommended in order to minimize saturation effects and to avoid specific absorption rate (SAR) problems. Receiver Bandwidth : Greater or equal to ± 31.25 kHz (or ~250 Hz/pixel) Field of View (FOV) and Partial Fourier (“fractional echo” and/or reduced phase-encoding FOV) as needed to meet temporal resolution requirements Number of Slices: Acceptable: ≥10 prior to zero fill. Ideal: as many as possible while maintaining ideal temporal resolution. Slice thickness : Ideal : <5 mm, Target : 5.1-6 mm, Acceptable : 6.1-8 mm Matrix: 256 x 160 (before applying rectangular FOV) – in order to meet 1-2mm in-plane spatial resolution Number of acquisitions (phases): Sufficient to allow acquisition of at least 5 minutes of post injection data plus at least 5 phases acquired before contrast agent injection (baseline images). Digitized bit depth: The maximum dynamic range should be utilized, e.g., “extended

dynamic range” or equivalent. Temporal resolution < 10sec.

http://www.rsna.org/QIBA_.aspx