HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Maris, T. G. Articles by Gourtsoyiannis, N. Search for Related Content PubMed PubMed Citation Articles by Maris, T. G. Articles by Gourtsoyiannis, N.

Transtympanic Iontophoresis with a Biocompatible Paramagnetic Solution at MR Imaging: Experimental Feasibility Study in Rabbits¹

¹ From the Department of Medical Physics, University Hospital of Heraklion, Crete, Greece (T.G.M.); and the Departments of Radiology (P.P., N.P., N.G.) and Otolaryngology (P.C., P.G.D., E.S.H.), Medical School of Crete, PO Box 1393, 71500 Stavrakia, Heraklion, Crete, Greece. Received July 6, 2001; revision requested August 20; revision received October 24; accepted November 12. Address correspondence to P.P. (e-mail: tmaris@med.uoc.gr).

View larger version (52K): [in a new window]   Figure 1. Plot of deionized water solvent SImean values and gadopentetate dimeglumine SImean values from solutions with six concentrations as a function of repetition time with the SE sequence. Error bars represent SDmean values for the deionized water and the gadopentetate dimeglumine solution with a 2 mmol/L concentration. Data were obtained from the means of SIs measured from ROIs on three consecutive transverse sections. Gadopentetate dimeglumine solution with a concentration of 2 mmol/L showed maximum SImean at repetition times of 250 msec or greater and was selected in the animal studies.

View larger version (52K): [in a new window]   Figure 2. Plot of deionized water solvent SImean values and gadopentetate dimeglumine SImean values from solutions with six concentrations as a function of flip angle with the GRE sequence. Error bars represent SDmean values for the deionized water and the gadopentetate dimeglumine solution with a concentration of 2 mmol/L. Data were obtained from the means of SIs measured from ROIs on three consecutive transverse sections. Gadopentetate dimeglumine solution with a concentration of 2 mmol/L showed maximum SImean at flip angles of 50° or greater. A 90° flip angle showed maximum relative contrast and was selected in the animal studies.

View larger version (127K): [in a new window]   Figure 3a. Images show circular ROI measurements in five anatomic areas. Transverse (a) SE (500/14; flip angle, 90°) and (b) GRE (300/10; flip angle, 90°) MR images. A = anterior, P = posterior, 1 = left middle ear cavity, 2 = neck muscle, 3 = subcutaneous fat, 4 = brain tissue, and 5 = left external ear canal. Image quality in a is superior to that in b. Flow artifacts (arrows) are present only on image obtained with GRE sequence.

View larger version (122K): [in a new window]   Figure 3b. Images show circular ROI measurements in five anatomic areas. Transverse (a) SE (500/14; flip angle, 90°) and (b) GRE (300/10; flip angle, 90°) MR images. A = anterior, P = posterior, 1 = left middle ear cavity, 2 = neck muscle, 3 = subcutaneous fat, 4 = brain tissue, and 5 = left external ear canal. Image quality in a is superior to that in b. Flow artifacts (arrows) are present only on image obtained with GRE sequence.

View larger version (122K): [in a new window]   Figure 4. Coronal T1-weighted SE MR image (500/14; flip angle, 90°) shows high SI observed in the left middle ear cavity (arrow on right side of image); iontophoresis was performed in the left ear. Note the absence of SI in the contralateral right middle ear cavity (arrow on left side of image). F = feet, H = head.

View larger version (121K): [in a new window]   Figure 5. Coronal T1-weighted SE MR image (500/14; flip angle, 90°) shows high SI within a semicircular canal in the left ear (arrow on right side of image), in which iontophoresis was performed. The corresponding right semicircular canal demonstrates low SI (arrow on left side of image). F = feet, H = head.