American Journal of Neuroradiology 2009;30:1149.
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American Journal of Neuroradiology
DOI 10.3174/ajnr.A1501
PEDIATRICS
Maturation of the Olfactory Bulbs: MR Imaging Findings
From the Department of Pediatric Radiology, University Children's Hospital UKBB, Basel, Switzerland.
Please address correspondence to J.F. Schneider, Department of Pediatric Radiology, University Children's Hospital UKBB, Römergaße 8, 4058 Basel, Switzerland; e-mail: jacques.schneider{at}ukbb.ch
BACKGROUND AND PURPOSE: The detection of time-related maturational changes of the olfactory bulb (OB) on MR imaging may help early identification of patients with abnormal OB development and anatomic-based odor-cueing anomalies.
MATERIALS AND METHODS: Two separate reviewers retrospectively analyzed coronal T2-weighted spin-echo MR images of the frontobasal region in 121 patients. There were 22 patients who underwent MR imaging examinations several times, accounting for a total of 156 studies. Age range was 1 day to 19.6 years. OBs were bilaterally identified in all cases and categorized according to their shape and signal intensity.
RESULTS: Three different anatomic patterns were identified. In pattern 1 (median age, 15 days; age range, 1–168 days), the OBs were round to oval with a continuous external T2-hypointense rim and a prominent T2-hyperintense central area. In pattern 2 (median age, 287 days; age range, 4 days–22 months), the OBs were U shaped, with thinning and concave deformation of the superior layer. A hyperintense central area on T2-weighted images was still visible. In pattern 3 (median age, 5.2 years; age range, 107 days–19.6 years), the OBs were small, round, or J shaped with a more prominent lateral part. No difference in signal intensity between the central area and the peripheral layer was identified anymore.
CONCLUSIONS: The OBs show time-related maturational changes on MR imaging. There is a progressive reorganization of the peripheral neuronal layers and signal intensity changes of the central area, which are completed at the end of the second year, paralleling cerebral maturational changes.