Blurring Cancellation

Blurring Cancellation acquires k-space twice, with the second pass being acquired in the reverse order. It minimizes image ghosting by reducing the amount of time between the first and second acquisition of each line in k-space.

Use Blurring Cancellation for breath hold abdominal imaging when a dual acquisition is required. The sequential-slice-ordering technique can result in fewer misregistration problems that typically occur with interleaved slice ordering.

• It uses a multiple NEX technique to average signals to reduce ghosting artifacts.
• It can add to acquisition time with 1 NEX acquisitions.
• It decreases ghosting, especially on 1 NEX scans, but increases the breath hold duration. Acqs before Pause must be set to 1 to enable breath hold slice ordering. This allows a pause between groups of slices for free breathing.
• It should NOT be used with 1 NEX in combination with ASSET. It degrades image quality.
• It is most effective when the echo from the center k-space phase encoding represents the middle of the echo train. It has minimum effect when the center k-space echo represents the beginning or end of the echo train. Therefore, select an odd ETL value and make the effective TE the mid-point between the shortest and the longest echo. For example, if you are prescribing a 3 ETL acquisition with a minimum TE of 15 ms (the echo space), then program the effective TE to 30 ms (30 is the midpoint between echoes 15, 30, and 45).
• A lower TR can be used at no expense to contrast-to-noise; this also helps to reduce overall scanning time.