MR imaging using specialized coils.

Abstract

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.

Magnetic Resonance Imaging of Cutaneous Neoplasms: Clinicopathologic Correlation

“…MRI does not utilize ionization radiation and, therefore, like ultrasound techniques, is believed to be harmless to the patient 11 . Development of an MRI surface coil that facilitates imaging of small and superficial structures 12 made MRI the radiologic technique of choice for evaluation of certain soft tissues, 13 orbital, 14 and musculoskeletal system neoplasms 15 . This report and recently published data by these and other authors 1–4 indicate that MRI has a definite role in dermatology.…”

Optimization of the number of selectable channels for spine phased array coils for transverse imaging

“…7 Image-J software (National Institutes of Health, Bethesda, MD, USA) was used for ROI outlining and signal intensity measurement. Comparisons among the four coil combinations were statistically analyzed, and a paired t-test with Bonferroni correction was made for SNR values from the images obtained using four coils and each of the other combinations.…”

High-resolution imaging at 3T and 7T with multiring local volume coils

“…In our design approach for a lower noise and higher signal, we considered the issues mentioned in the literature [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. To compare SNR, we assume uniform excitation in all cases of (A) volume coil; (B) volume transmit, surface coil receive; and (D) multiring surface coil.…”