Katsuhiro Kida, Presenter: Nothing to Disclose

Sachiko Goto, Abstract Co-Author: Nothing to Disclose

Satoshi Kuwahara, Abstract Co-Author: Nothing to Disclose

Toshinori Maruyama, Abstract Co-Author: Nothing to Disclose

Tsutomu Kajitani, Abstract Co-Author: Nothing to Disclose

Yoshiharu Azuma PhD, Abstract Co-Author: Nothing to Disclose

Although the limit of detection of calcifications was 1.0 mm, it suggests a possibility that the high-pass filtered phase image is able to use for the breast cancer screening and diagnosis without the necessity of compression or the use of ionizing radiation.

Currently, mammography is the gold standard for breast cancer screening. The presence of microcalcifications in breast tissues is of great importance since microcalcifications are mammographic characteristics of early breast cancer. Since mammography is a projection technique, the breast has to be compressed to increase image quality and to reduce radiation dose. However, the breast compression causes strong pain for women with dense breast tissue and younger women. Furthermore, mammography requires the breast to be exposed to ionizing radiation.

To achieve detection of calcifications using magnetic resonance imaging (MRI) for breast cancer screening, we investigate the optimized high-pass filtered phase image using breast phantom. Since a difference of phase is enhanced at sufficiently long TE, optimization of TE was required. The TE was changed from 14 to 48 msec at 6.9 msec in-phase intervals. However, longer TE tends to increase the static field inhomogeneity effects. To remove the static field inhomogeneity effects, we employed high-pass filter processing. Then, several different filter sizes were tested to optimize the visualization of calcification. These filters contained 16×16, 32×32, 64×64 and 128×128 pixels.

TE of 48 msec had the highest contrast between between calcification and gel phantom. On phase image, since extended TE caused phase changes strongly, phase change of small magnetic susceptibility can make large. That is, a phase image is effectively utilizable even if it is a low magnetic field system such as 1.0 T. However, longer TEs tend to increase the static field inhomogeneity effects. The high-pass filter was useful in removing the static field inhomogeneity effects. The high-pass filter size of 128×128 pixels was able to remove the background phase effects and was able to show calcification as a hyperintense.

Kida, K, Goto, S, Kuwahara, S, Maruyama, T, Kajitani, T, Azuma, Y, Phantom Study for Breast Cancer Screening Using High-Pass Filtered Phase Image in Magnetic Resonance Imaging.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11009456.html