Kookjin Ahn MD, PhD, Presenter: Nothing to Disclose

In Seong Kim PhD, Abstract Co-Author: Nothing to Disclose

Bum Soo Kim, Abstract Co-Author: Nothing to Disclose

The conventional MRIs with 60cm sized bores can make patients feel anxious and even cause claustrophobia. MRIs with 70cm sized bores have the advantage of a wider and more comfortable space for the patient. The purpose of our study is to compare the amount of motion in patients undergoing MRIs of two different size bores.

MR Imaging: the equipment used for the wide bore magnet (70 cm bore size) was MAGNETOM Verio 3.0T (Siemens) and for the narrow bore magnet (60 cm bore size), MAGNETOM Avanto 1.5T (Siemens) and Achieva 1.5T (Phillips). An EPI pulse sequences with following parameters: TR 3000 ms, total scanning time 5 min 6 sec, total 100 scans of the whole brain were applied. 60cm vs. 70cm bore size comparison: while fifteen volunteers (M : F = 9 : 6, 29 – 45 years) underwent 100 scans of 60cm bore and 70cm bore MRIs, SPM was used for realignment of the images and to compare the differences in the images to detect the amount of motion between them. The amount of motion of each scan was detected from the difference between the first image. Each difference was measured by the distance and angle and cumulated to compare between the 60cm and 70cm bore MRIs. Statistical Analysis: independent samples t-test from the SPSS was used to compare the two groups.  

More motion was detected in the 60cm bore MRIs in X translation, Y translation, Z translation, X rotation, Y rotation, and Z rotation. There were statistically significant differences between the two groups in the X translation (60 cm 2.2558 1.08263, 70 cm 1.0424 0.37330, p-value 0.03) and Z rotation (60 cm 0.0341 0.00742, 70 cm 0.0203 0.0069, p-value 0.007).

We have found that motion amount is significantly decreased in MRIs with wider bores, supporting the assumption that patients may feel more comfortable in the larger bore MRI and move less.

Wider bore magnet MRI has the benefit in reducing the patient's motion as compared with the narrower bore magnet MRI.

Ahn, K, Kim, I, Kim, B, Benefit of Wide-Bore Magnet In Reducing Patient’s Motion: Comparison with Narrow-Bore Magnet.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9014660.html