Cook’s interventional MReye Needles are used for initial puncture and positioning control as well as biopsies and other interventional procedures in combination with Magnetic Resonance Imaging.

• MReye products are created from a nonferromagnetic material that helps prevent disturbing artifacts.
• MReye needles are recommended for use with MRI scanners not exceeding 1.5 tesla.

To see different-sized images of the needle, try these scanner parameters:

• To see an image of the needle at a ratio of 1:1, select a spin echo sequence (TR/TE 200 ms/15 ms).
• To see an image of the needle enlarged approximately 2:1, select a gradient echo sequence (TR/TE/Flip angle 336 ms/15 ms/90°).

Nonclinical testing demonstrated that the Vital-Port Vascular Access Ports are MR Conditional. A patient with one of these implants can be safely scanned immediately after placement under the following conditions:

• Static magnetic field of 3.0 tesla or less
• Maximum spatial gradient magnetic field of 720 gauss/cm
• Maximum MR system reported whole-body averaged specific absorption rate (SAR) of 3 W/kg for 15 minutes of scanning

In nonclinical testing, the vascular access ports produced maximum temperature increases of less than or equal to 0.7°C at maximum MR system reported whole-body averaged specific absorption rate (SAR) of 3 W/kg for 15 minutes of MR scanning in a 3 tesla MR system using a transmit/receive body coil (Excite, software G3.0-052B, GE Healthcare, Milwaukee, WI).

MR image quality may be compromised if the area of interest is in the same area or relatively close to the position of the vascular access ports. Therefore, it may be necessary to optimize MR imaging parameters to compensate for the presence of one of these implants.

When using an MReye® Kopans Breast Lesion Localization Needle, do not exceed a magnet strength of 1.5 Tesla. MReye needles provide optimal artifact (distortion) results when a 1.5 Tesla magnet rate is used.

For MReye Needles

• Circumferential image distortion may occur around the body of the needle when the needle is oriented perpendicular to the magnetic field.
• RF heating of the needle may occur during MRI procedures. Heating effects are theoretically greatest when the needle is oriented along the length of the bore, near the bore wall.
• If using fast scan protocols, there is a theoretical possibility that peripheral nerve stimulation may occur under worst-case conditions (needle with inserted trocar oriented along the length of the bore, near the bore wall).
• Before using MReye Needles, physicians should have extensive training and experience with interventional magnetic resonance imaging.
• Different sizes of needle and hookwire on the image may be obtained. The following scanner parameters are recommended: A spin-echo sequence (TR/TE 200ms/15ms) will provide an image depicting the needle and hookwire 1:1. A gradient-echo sequence (TR/TE/flip angle 336ms/5ms/90°) will provide an image depicting the needle and hookwire enlarged approximately 2:1.
• Evaluation of image distortion was performed using a 1.5 Tesla scanner and SE (Spin Echo) and GRASS (Gradient-Recalled Acquisition in the Steady State) MRI sequences, with the device in two different orientations (0° and 90°) and the MRI parameters as shown in the following table. Results of this testing show that under worst-case conditions in terms of artifact size and needle position, circumferential image distortion of up to 2 cm may occur around the body of the needle when the needle is oriented perpendicular to the magnetic field using the GRASS sequence. Under these conditions, error in determining needle tip position may be as much as 1 cm.

MRI Parameters for Image Distortion Testing

Non-clinical testing demonstrated that the MReye Breast Localization Coil is MR conditional. A patient with this device can be scanned safely under the following conditions:

• Static magnetic field of 3 Tesla or less
• Maximum spatial gradient magnetic field of 720 Gauss/cm or less
• Maximum whole-body-averaged specific absorption rate (SAR) of 3.0 W/kg for 15 minutes of scanning.

In non-clinical testing, the MReye Breast Localization Coil produced a temperature rise of less than 2.6°C at a maximum whole-body-averaged specific absorption rate (SAR) of 2.9 W/kg, as assessed by calorimetry for 15 minutes of MR scanning in a 1.5 Tesla/64 MHz, Magnetom, Siemens Medical Solutions MR scanner. In non-clinical testing, the MReye Breast Localization Coil produced a temperature rise of less than 3.6°C at a maximum whole-body-averaged specific absorption rate (SAR) of 3.0 W/kg, as assessed by calorimetry for 15 minutes of MR scanning in a 3 Tesla/128 MHz, Excite, Software G3.0-052B, General Electric Healthcare MR scanner.

MR image quality may be compromised if the area of interest is in the same area or relatively close to the position of the following items for the MReye Breast Localization Coil:
(1) Stylet, needle, and coil in place
(2) Coil only

Therefore, optimization of MR imaging parameters to compensate for the presence of these devices may be necessary.

(1) Stylet, needle cannula, and coil

(2) Coil only