Comparison of lesion enhancement on spin-echo and gradient-echo images.
OBJECTIVE
To compare lesion enhancement after injection of gadopentetate dimeglumine on spin-echo and gradient-echo T1-weighted images.


METHODS
A total of 48 contrast-enhancing intracranial lesions were evaluated using a spin-echo and two gradient-echo T1-weighted pulse sequences. Percent contrast, contrast-to-noise, and signal-to-noise measurements were made on the spin-echo T1-weighted, three-dimensional gradient-echo, and multiplanar gradient-echo sequences.


RESULTS
The measurements were somewhat different for the following categories of lesions: extraaxial, intraaxial with edema, and intraaxial without edema. The latter group provided the greatest diagnostic challenge: three of 19 such lesions 1 cm in size or smaller could not be identified on three-dimensional gradient-echo images, and one could not be identified on multi-planar gradient-echo images. The spin-echo T1-weighted sequence demonstrated significantly higher percent contrast (P < .05) and greater contrast to noise (P < .03) than either gradient-echo sequence for these small intraaxial lesions without edema. For extraaxial and intraaxial lesions with edema, percent C was similar for spin-echo T1-weighted and three-dimensional gradient-echo images, while contrast to noise was greater for spin-echo T1-weighted images. This reflected greater tissue noise with gradient-echo sequences.


CONCLUSIONS
The T1-weighted spin-echo sequence was preferred for detecting the full spectrum of contrast-enhancing lesions of the central nervous system.
Chappell
P M
PM
Department of Radiology, S072, Stanford University School of Medicine, CA 94305-5105.
Pelc
N J
NJ
Foo
T K
TK
Glover
G H
GH
Haros
S P
SP
Enzmann
D R
DR
D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology*; D001927:Brain Diseases / Q000175:diagnosis; D001929:Brain Edema / Q000175:diagnosis; D003287:Contrast Media; D004338:Drug Combinations; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives; D011446:Prospective Studies
D003287:Contrast Media; D004338:Drug Combinations; D009942:Organometallic Compounds; D008536:Meglumine; D004369:Pentetic Acid; D019786:Gadolinium DTPA