T1Relaxation Measurement ofEx-VivoBreast Cancer Tissues at Ultralow Magnetic Fields

Abstract

We investigated T 1 relaxations of ex-vivo cancer tissues at low magnetic fields in order to check the possibility of achieving a T 1 contrast higher than those obtained at high fields. The T 1 relaxations of fifteen pairs (normal and cancerous) of breast tissue samples were measured at three magnetic fields, 37, 62, and 122 μT, using our superconducting quantum interference device-based ultralow field nuclear magnetic resonance setup, optimally developed for ex-vivo tissue studies. A signal reconstruction based on Bayesian statistics for noise reduction was exploited to overcome the low signal-to-noise ratio. The ductal and lobular-type tissues did not exhibit meaningful T 1 contrast values between normal and cancerous tissues at the three different fields. On the other hand, an enhanced T 1 contrast was obtained for the mucinous cancer tissue.

SQUID-Based Magnetic Resonance Imaging at Ultra-Low Field Using the Backprojection Method

“…For example, the ULF MRI approach may provide open MRI systems for airport security [11], emergency rooms, and field hospitals [20,25], and it can also be combined with magnetoencephalography (MEG) for recording both anatomical and functional (biomagnetic) information about the brain [23,24]. Moreover, the unique advantage of ULF MRI is the higher T 1 -contrast in low-field MRI which has been proposed for the discrimination of tissue [35][36][37]. is Concepts in Magnetic Resonance Part B, Magnetic Resonance Engineering enhanced T 1 -contrast is a prospective supplement to highfield MRI in pathology studies using the SQUID-based ULF MRI.…”

Ultralow‐field and spin‐locking relaxation dispersion in postmortem pig brain

“…As a step toward developing clinical methods, it would be advantageous to estimate the sensitivity and specificity of ULF‐MRI to molecular processes likely to be found in pathology, and to quantify relaxation times pertinent to image contrast. For example, studies of excised specimens have demonstrated that ULF relaxation times can differentiate tumors from normal tissues .…”

Magnetic resonance imaging without field cycling at less than earth's magnetic field

“…In order to create a stronger B p , various types of B p coils have been used, such as a permanent magnet 1 and coils with the following cooling agents: forced air, 2 water, 3,4 a fluorine-based industrial coolant, 5 liquid helium, 6,7 and liquid nitrogen. [8][9][10][11][12] In spite of these efforts, the strength of B p has been limited to below approximately 150 mT. 3 Increasing the magnitude of the B p has also yielded unwanted effects: flux trapping in the superconducting pickup coil 7 and the generation of eddy currents on the walls of a magnetically shielded room (MSR).…”

“…Currently, a strong pre-polarization field (B p ) is indispensable for increasing the signal-to-noise ratio (SNR) in most superconducting quantum interference device (SQUID)-based ultra-low field (ULF) nuclear magnetic resonance (NMR)/magnetic resonance imaging (MRI) studies. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The field should be applied for a while before acquisition, because a static magnetic field (B m ) operating in the micro-tesla range cannot generate sufficient nuclear spin polarization. There are some challenges involved in producing a strong B p , which is one of the critical issues in ULF-NMR/MRI.…”