Multiple TR Acquisitions

Multiple TR Acquisition (User CV 16) can be turned on or off for VIBRANT-Flex acquisitions. It is used to enable a single echo per TR mode for VIBRANT-Flex scans. When the CV is off, both in-phase and out-of-phase echoes are acquired within a single TR. When the CV is on, the in-phase and out-of-phase echoes are acquired in multiple TRs. Setting this CV to 1 increases the scan time but minimizes chemical shift affect. Also, TE and TE2 values can change when the User CV is on. Chemical shift artifact visibility increases when the Minimum TE increases above 1.4 ms. Therefor, consider adjusting scan parameters (primarily Frequency and Slice thickness) to keep the Minimum TE value below 1.4 ms to minimize chemical shift affect.The Frequency matrix value that can be prescribed is higher in a Multiple TR acquisition.

There are two VIBRANT-Flex protocols. One has User CV 16 turned on and the other protocol has it turned off.

• Chest > Breast Routine > Axial VIBRANT-Flex has User CV 16 turned On. It is recommended to use this protocol when higher spatial resolution is preferred. The protocol is a high resolution protocol and the User CV collects the data in a manner that minimizes chemical shift artifacts. There is a scan time penalty when the User CV is on. Acceleration can be used to decrease the scan time in this mode, if needed.
• Chest > Breast Routine > Axial VIBRANT-Flex Temporal Resolution High has User CV 16 turned Off.