Medtronic 3391S-40 Technical Manual

Cranial scans

This document contains guidance for developing imaging protocols for the SureTune™ 4 Software. Use the information in “ types of preoperative and postoperative scans), and then refer to the additional requirements for each scan type starting with “Cranial MRI scans only” on page 2. Using the requirements for preoperative and postoperative scans included in this document will help to provide scans that are appropriate for use with SureTune™ 4 Software.

Note: The registration algorithms have been tested to perform accurately when using the

requirements described in this document.

For all scans, keep the patient as motionless as possible.

Cranial scan requirements

D00565102-IP-EN

Rev. B

2021-09

Imaging Protocols for

SureTune™ 4 Software

Cranial scan requirements” on page 1 (which applies to all

Contrast Contrast agents may be injected before scanning.

Slices For patient scans that will be used with the SureTune

into account.

• Use a constant slice thickness.

• Use a slice thickness of 1 mm or less, which usually produces the highest quality data set for image segmentation, localizing a lead model, and planning stimulation with SureTune™ 4 Software.

• For preoperative images, axial or coronal slices are preferred (MRI scans can be acquired in the axial orientation or reformatted into axial slices).

• Scan contiguous slices. (Slice spacing must equal slice thickness. Make sure that there is no gap or overlap between slices).

1: Figure 1: Contiguous slice scan

Correct: contiguous slices with no gap and no overlap

Incorrect: gap between slices

Incorrect: overlap of slices

™

4 Software, take the following guidance

D00565102-IP-EN Rev. B Medtronic, Inc. 1

710 Medtronic Parkway, Minneapolis, MN 55432 USA

Size and pixels • Use a square image matrix of 256 x 256 pixels or 512 x 512 pixels.

• Use square pixels.

Cranial MRI scans only

Cranial CT scans only

For MRI scans, use the information in “Slices” on page 1 and “Size and pixels” on page 2 in conjunction with the following information.

• Use axial or coronal slices for preoperative MR images. Scan along the axis of the magnet bore.

• Use single-echo scans. Do not use multi-echo scans.

• Any MR imaging sequence can be used to show anatomy. However, when registering an image to a reference image, MR-T1 and MR-T2, and combinations thereof have been evaluated and found effective for use with SureTune™ 4 Software. Other modalities, such as those listed in “Scans to merge” on page 3, have not been evaluated.

• MR 3D volume acquisition is acceptable as long as the scan can be reconstructed in a way that conforms to all requirements of the imaging protocol.

For CT scans, use the information in “Slices” on page 1 and “Size and pixels” on page 2 in conjunction with the following information.

• Use a standard soft tissue algorithm.

• Use axial slices for postoperative CT or O-arm™ images.

• Do not use gantry tilt.

• Use a circular (or square) field of view (FOV). Use the smallest FOV to encompass the region of interest, which is usually 28

• Include both anterior commissure (AC) and posterior commissure (PC) anatomy and the target region within the scan.

• 8-bit or 16-bit reconstructions are supported (16-bit reconstructions are recommended to obtain a higher image dynamic range).

cm to 32 cm (280 mm to 320 mm).

Cranial O-arm™ scans only

For O-arm™ scans, use the information in “Slices” on page 1 and “Size and pixels” on page 2 in conjunction with the following information.

• For postoperative lead placement scans, use 20 cm FOV protocols (High Definition [HD], Enhanced Cranial, Standard, Low Dose).

Patient position • Make sure that the patient anatomy is oriented as close as possible to LPS space (the left-right,

anterior-posterior, and inferior-superior axes).

• Separate the patient’s head from the scanner headrest with towels or foam.

• Use padding to prevent patient motion, but make sure that the padding does not distort any fiducial markers or the skin.

• Make sure that the patient's ears do not touch the sides of the headrest, and that they are not pushed away from their normal position.

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