AutoAlign

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Image 1

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Image 2

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Image 3

MR Technique: 

Three series of scout images, to be used for slice positioning in a MR scan of the brain, are illustrated. The first is a typical scout (1), using 2D FLASH technique, with images acquired, as is common today, in the three orthogonal directions. These three directions (sagittal, coronal, and axial) are respective to the main magnetic field, but not to the anatomy of the patient. Note that the patient is less than perfectly positioned, a common occurrence in clinical practice, with the cause multifactorial. The second series of scout images (2) is acquired using a 3D VIBE scan, with the scan time however no longer than for the acquisition of the three scouts shown in (1), approximately 15 seconds. Illustrated are the images already after the initial iteration in slice positioning by the AutoAlign algorithm. The third series of scout images (3) is the final result from AutoAlign, which is produced automatically without user intervention. The axial images have been correctly chosen to span the brain from the vertex to the skull base, the plane of reference (alignment) has been chosen to be the equivalent of the AC-PC line (anterior commissure to posterior commissure), and the images are orthogonal to the coronal plane.

Imaging Findings:

AutoAlign makes possible reproducible positioning of the patient, without operator intervention. This holds the advantage of standardization of image quality from patient to patient, and in addition for the same patient on followup exams. Higher overall image quality can be achieved by standardizing the selection of imaging plane (tilt), as well as correcting for alignment in both axes – in this example axial and coronal. Likely just as important is the improvement in patient throughput. The process can be started in the scan room as the patient is centered in the magnet, with the scout thus complete and the first set of images already initiated (the sagittal series in this instance) automatically as the technologist is returning to the operator’s console. Approaches like AutoAlign can be applied in many anatomic areas to permit better standardization in terms of plane selection and to improve workflow, with other common applications being the knee and spine.

Acknowledgment: these scans were acquired with the assistance of Martin Harder and Katrin Wohlfarth of Siemens AG, Healthcare Sector.