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Variability in the enhancement of the normal central skull base in children
G R Applegate1, W L Hirsch, L J Applegate
1University of Pittsburgh, Department of Diagnostic Radiology, Pennsylvania.
Insights
Contrast enhancement of the pediatric skull base is variable. Gadolinium-DTPA MRI shows normal enhancement patterns that should not be mistaken for pathology in children.
Area of Science:
- Pediatric Radiology
- Neuroimaging
- Magnetic Resonance Imaging
Background:
- The central skull base undergoes significant changes during childhood.
- Understanding normal MRI signal and enhancement characteristics is crucial for accurate diagnosis.
Purpose of the Study:
- To prospectively evaluate the signal and enhancement patterns of the central skull base in children using 1.5 T MRI.
- To differentiate normal enhancement from potential pathological findings in pediatric skull base imaging.
Main Methods:
- 40 children (13 days to 8 years) underwent sagittal spin echo MRI before and after gadolinium-DTPA administration.
- Three observers assessed contrast enhancement, signal intensity, pneumatization, and marrow fatty replacement.
- Standard sequences were used with identical window and level settings for comparison.
Main Results:
- No or mild enhancement of the basisphenoid and basiocciput was observed in 16-44% of cases post-gadolinium.
- Moderate to intense enhancement occurred in 28-42% of cases.
- Irregular fatty replacement did not preclude intense enhancement of residual hematopoietic elements.
Conclusions:
- Normal central skull base enhancement in children can be variable and may mimic pathology.
- Radiologists must be aware of these normal variations to avoid misinterpreting them as neoplastic invasion.
- This study provides a reference for normal pediatric central skull base MRI findings.
Abstract:
We studied the signal and enhancement characteristics of the central skull base prospectively in 40 children aged 13 days to 8 years, on a 1.5 T MRI system. Identical standard short TR/TE spin echo sequences in the sagittal plane were performed before and after intravenous gadolinium-DTPA. The sequences used for comparison were filmed at identical window and level settings. Three independent observers assessed (1) the intensity of contrast enhancement of the basisphenoid, basiocciput and presphenoid, (2) the signal intensity of the spheno-occipital synchondrosis, (3) the degree of pneumatization of the sphenoid sinus and (4) the uniformity of signal intensity reflecting fatty replacement of the marrow of the basisphenoid, basiocciput and presphenoid. In 16% and 28% respectively of cases there was no enhancement of the basisphenoid and basiocciput after gadolinium administration; in 42% and 44% there was mild enhancement, and moderate or intense enhancement was observed in 42% and 28% of cases. Even when there was irregular fatty replacement, residual hemopoietic clements could enhance intensely. When skull base neoplasms are being investigated, the normal signal irregularity and enhancement of the central skull base in children must not be confused with pathologic invasion of the marrow.