Proton magnetic resonance spectroscopy in pituitary macroadenomas: preliminary results.
OBJECTIVE
The aim of this study was to correlate proton MR (1H-MR) spectroscopy data with histopathological and surgical findings of proliferation and hemorrhage in pituitary macroadenomas.


METHODS
Quantitative 1H-MR spectroscopy was performed on a 1.5-T unit in 37 patients with pituitary macroadenomas. A point-resolved spectroscopy sequence (TR 2000 msec, TE 135 msec) with 128 averages and chemical shift selective pulses for water suppression was used. Voxel dimensions were adapted to ensure that the volume of interest was fully located within the lesion and to obtain optimal homogeneity of the magnetic field. In addition, water-unsuppressed spectra (16 averages) were acquired from the same volume of interest for eddy current correction, absolute quantification of metabolite signals, and determination of full width at half maximum of the unsuppressed water peak (FWHM water). Metabolite concentrations of choline-containing compounds (Cho) were computed using the LCModel program and correlated with MIB-1 as a proliferative cell index from a tissue specimen.


RESULTS
In 16 patients harboring macroadenomas without hemorrhage, there was a strong positive linear correlation between metabolite concentrations of Cho and the MIB-1 proliferative cell index (R = 0.819, p < 0.001). The metabolite concentrations of Cho ranged from 1.8 to 5.2 mM, and the FWHM water was 4.4-11.7 Hz. Eleven patients had a hemorrhagic adenoma and showed no assignable metabolite concentration of Cho, and the FWHM water was 13.4-24.4 Hz. In 10 patients the size of the lesion was too small (< 20 mm in 2 directions) for the acquisition of MR spectroscopy data.


CONCLUSIONS
Quantitative 1H-MR spectroscopy provided important information on the proliferative potential and hemorrhaging of pituitary macroadenomas. These data may be useful for noninvasive structural monitoring of pituitary macroadenomas. Differences in the FWHM water could be explained by iron ions of hemosiderin, which lead to worsened homogeneity of the magnetic field.
Stadlbauer
Andreas
A
Department of Neurosurgery, University of Erlangen-Nuremberg, Erlangen, Germany.
Buchfelder
Michael
M
Nimsky
Christopher
C
Saeger
Wolfgang
W
Salomonowitz
Erich
E
Pinker
Katja
K
Richter
Gregor
G
Akutsu
Hiroyoshi
H
Ganslandt
Oliver
O
D049913:ACTH-Secreting Pituitary Adenoma / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D000236:Adenoma / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D002455:Cell Division; D005260:Female; D049912:Growth Hormone-Secreting Pituitary Adenoma / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D006801:Humans; D020300:Intracranial Hemorrhages / Q000378:metabolism / Q000473:pathology; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D015175:Prolactinoma / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D011522:Protons
D011522:Protons