Rotator cuff tears: Preliminary application of high-resolution MR imaging with counter rotating current loop-gap resonators

J. B. Kneeland, G. F. Carrera, W. D. Middleton, N. F. Campagna, L. M. Ryan, A. Jesmanowicz, W. Froncisz, J. S. Hyde

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

A new class of radio frequency (RF) coils for magnetic resonance (MR) imaging and spectroscopy is introduced. The coils consist of two loop-gap resonators of equal diameters positioned along a common axis. They are tuned to the mode in which the current in the two loops flows in opposite directions. These coils are 'decoupled' from a uniform excitation field of arbitrary orientation (including circularly polarized fields) by intrinsic decoupling and by means of back-to-back fast recovery diodes. Measurements made with the coils and a phantom saline tank indicate that the signal-to-noise ratio obtainable with these coils is almost identical to that obtained with single loops. Imaging of several anatomic areas, including knee, wrist, and shoulder, has been performed with a 1.5-T MR system that uses circularly polarized RF. A small series of patients with torn rotator cuffs underwent imaging. Difficulties in establishing the diagnosis with MR imaging because of anatomic complexity are illustrated. The value of pulse sequences with long repetition times to increase the signal intensity of fluid in the joint is shown.

Original languageEnglish
Pages (from-to)695-699
Number of pages5
JournalRadiology
Volume160
Issue number3
DOIs
StatePublished - Jan 1 1986
Externally publishedYes

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