Medrad ecoil

Patients underwent preoperative MRI with a 3T Philips Achieva MR system with a 6-channel cardiac phased array coil placed around the pelvis, and with an endorectal coil (Medrad eCoil, Bayer Healthcare). To limit peristalsis of the rectal wall 1mg dose of Glucagon (Glucagon, Eli Lilly & Co., Indianapolis) was injected prior to imaging. T2W images and multi echo T2W images were acquired, and only patients who underwent T2 mapping were included in the study. The echo times used were 90, 150, and 180 ms. The field-of-view was 160 mm x 160 mm and the matrix size was 212 x 212 with an in-plane resolution of 0.75 x 0.75 mm. The repetition time (TR) was 7.5 ms.

Solid ERCs consisting of two loop elements (ERC-2L) were built by placing two rectangular loops on a 2.2 cm diameter 7.2 cm long solid cylindrical core. The short axis of each loop was 1.9 cm with an overlap of 0.3 cm (Figure 1.a). Both a transceiver and an actively detuned receive-only versions of the ERC-2L were constructed following the same geometry. A commercial version with the same general geometry of the ERC-2L is available for 1.5 and 3 T (Sentinelle Endorectal Coils, Invivo, Gainesville, FL).
In addition to the ERC-2L design, a transceiver version of a two-channel microstrip-loop ERC (ERC-ML) was built. The ERC-ML had a 2.2 cm diameter 7 cm long cylindrical core. The ground plane of the microstrip element was placed on the center axis of the core and the loop element was centered around the top conductor of the microstrip element with a short-axis diameter of 1.4 cm (Figure 1.c). The ERCs were positioned inside a sterilizable housing when used in any imaging or heating studies (Figure 1.e).
A previously described single-channel receive-only balloon-type ERC (ERC-b) was used for comparison by replacing the electrical components of a commercially available 3 T coil (Medrad eCoil, Bayer Healthcare, Whippany, NJ) (23 ). The size of the ERC-b loop was 7 × 3.5 cm².