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Pituitary microadenomas: experience with Gd-DOTA-enhanced MR imaging at 0.5 Telsa
M Hamon-Kérautret1, X Leclerc, D Dewailly
1Department of Neuroradiology, Hôpital B, C.H.R.U. Lille, France.
Purpose:
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.
Conclusion:
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.
Insights
The early postcontrast MRI sequence is most effective for detecting pituitary microadenomas. Precontrast scans are vital for identifying hemorrhagic lesions, while late postcontrast scans offer minimal additional diagnostic value.
Area of Science:
- Radiology
- Neuroradiology
- Medical Imaging
Background:
- Pituitary adenomas are common tumors.
- Accurate radiological diagnosis is crucial for effective treatment.
- Magnetic resonance imaging (MRI) is a key tool for pituitary lesion detection.
Purpose of the Study:
- To evaluate the diagnostic utility of 0.5 Tesla MRI in identifying pituitary adenomas.
- To assess the added benefit of gadolinium contrast in detecting small intrasellar lesions.
Main Methods:
- Prospective study of 38 patients with pituitary microadenomas.
- Utilized three coronal T1-weighted MRI sequences: precontrast, early postcontrast, and late postcontrast.
- Lesion visibility was categorized as definite, probable, or absent for each sequence.
Main Results:
- Early postcontrast scans detected lesions in 89.5% of patients, significantly higher than precontrast (55%) or late postcontrast (60.5%).
- Nine microadenomas missed on precontrast scans were detected on early postcontrast images.
- Precontrast scans were essential for identifying one hemorrhagic microadenoma not seen on early postcontrast.
Conclusions:
- The early postcontrast MRI sequence is the most sensitive for detecting pituitary microadenomas.
- Precontrast imaging is necessary for identifying hemorrhagic lesions.
- Late postcontrast sequences provide limited additional diagnostic information and may be unnecessary.