Radiology, Vol 157, 443-447, Copyright © 1985 by Radiological Society of North America
MR imaging using specialized coils
MR Fisher, B Barker, EG Amparo, G Brandt, M Brant-Zawadzki, H Hricak and CB Higgins
The purpose of this study was to evaluate the clinical utility of
specialized coils with magnetic resonance (MR) imaging and to determine the
potential improvement in the signal-to-noise ratio (SNR) provided by the
various coils. A total of 48 patients were studied-33 with surface coils
and 15 with limb coils. MR imaging was performed with a superconducting
magnet operating at 0.35 T. Two applications of surface coils were
evaluated; one used for both transmitting and receiving and the other used
only for receiving. Structures studied with the surface coils included the
orbit, carotid artery, cervical and lumbar spine, parotid and thyroid
glands, other neck structures, femoral artery, kidney, prostate, hip, and
heart. The regions studied with the limb coil were the ankle, knee, wrist,
elbow and popliteal artery. We calculated the SNR, and the results
demonstrated a marked improvement with the specialized coils: a twofold
increase for the 10-cm surface coil versus the head coil and a 4.6-fold
increase compared with the body coil, a 2.3-fold increase for the 20-cm
surface coil compared with the body coil, and 2.8- and 6.4-fold increases
for the limb coil versus the head coil and the body coil, respectively. The
use of specialized coils was feasible in the clinical setting and they
provided a marked improvement in the image SNR, which facilitated the
imaging of small and superficial structures.
