Pituitary microadenomas: experience with Gd-DOTA-enhanced MR imaging at 0.5 Telsa.
OBJECTIVE
We report our experience with magnetic resonance imaging at 0.5 Tesla in the radiological diagnosis of pituitary adenomas.


METHODS
Over 2 years we performed a prospective study in 38 patients with pituitary microadenomas to assess the potential additional benefit of gadolinium in the detection of small intrasellar lesions. The protocol included three coronal T1-weighted sequences: precontrast, early postcontrast (obtained less than 2 min after injection) and late postcontrast (obtained 5 min after injection). For each sequence lesions were classified according to their visibility into three categories: definite lesion, probable lesion or absent lesion.


RESULTS
Lesions were classified as well-defined in 55% of patients on the precontrast study, 89.5% on the early postcontrast study and 60.5% on the late postcontrast study. Of nine microadenomas not detected on the precontrast scans, all were clearly seen on the early post contrast scans; only four were well-defined on the late postcontrast study. Only one lesion was not seen on the early postcontrast study but was well-defined on precontrast study as a spontaneous high-intensity focal area: it was a hemorrhagic microadenoma.


CONCLUSIONS
Our results suggest that the early postcontrast study is the most useful sequence for the detection of microadenomas. Precontrast image is necessary to detect hemorrhagic lesions; the late postcontrast sequence has a low additional diagnostic yield and seems unnecessary unless the other sequences are inconclusive.
Department of Neuroradiology, Hôpital B, C.H.R.U. Lille, France.
M
M
Hamon-Kérautret
X
X
Leclerc
D
D
Dewailly
J P
JP
Pruvo
P
P
Fossati
J
J
Clarisse
D000236:Adenoma / Q000097:blood / Q000175:diagnosis* / Q000473:pathology; D000293:Adolescent; D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000328:Adult; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D005682:Gadolinium / Q000008:administration & dosage; D006470:Hemorrhage / Q000175:diagnosis; D006571:Heterocyclic Compounds / Q000008:administration & dosage; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds / Q000008:administration & dosage; D010911:Pituitary Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000473:pathology; D011388:Prolactin / Q000097:blood; D015175:Prolactinoma / Q000473:pathology; D011446:Prospective Studies; D012658:Sella Turcica / Q000473:pathology
D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D000324:Adrenocorticotropic Hormone; D011388:Prolactin; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate; D005682:Gadolinium