“BLADE” and “PROPELLER” are terms used in MRI (Magnetic Resonance Imaging) to describe advanced imaging techniques that aim to reduce motion artifacts in images caused by patient movement during the scan. These techniques are particularly useful in situations where patients have difficulty remaining still, such as pediatric or critically ill patients.

BLADE (Balanced Steady State Free Precession Line Acquisition with Undersampling)

BLADE is an imaging technique that combines elements of steady-state free precession (SSFP) imaging with data undersampling and motion correction. It acquires multiple lines of k-space data during each repetition time, and the data from these lines are combined to create a single image. By acquiring data from multiple lines, BLADE can tolerate small motion artifacts, and the motion information within the lines can be used to correct for those artifacts during image reconstruction. This technique can help reduce blurring and ghosting caused by patient motion.

Sagittal blade imaging of the brain.

sagittal blade imaging of brain

Sagittal blade imaging of the spine.

sagittal blade imaging ofspine

PROPELLER (Periodically Rotated Overlapping Parallel Lines with Enhanced Reconstruction)

PROPELLER is another motion-correction technique that also utilizes undersampling. In PROPELLER, the k-space data is acquired in a segmented, radial manner, with each segment comprising several overlapping lines. The acquisition involves periodically rotating the readout gradient to gather data from different parts of k-space. The overlapping nature of the acquired data allows for robust motion correction during image reconstruction. PROPELLER can help create images that are less affected by motion artifacts, resulting in improved image quality, especially in cases of involuntary motion.


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  • Pipe, J. G. (1999). Motion correction with PROPELLER MRI: application to head motion and free-breathing cardiac imaging. Magnetic Resonance in Medicine, 42(5), 963-969. DOI: 10.1002/(SICI)1522-2594(199911)42:5<963::AID-MRM10>3.0.CO;2-F
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