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Subependymal Giant Cell Astrocytoma Size Measurement in Tuberous Sclerosis Complex: Noncontrast vs Contrast-Enhanced 3-Dimensional T1-Weighted Magnetic Resonance Imaging (MRI)

Purpose: Tuberous sclerosis complex is a multisystem genetic disorder characterized by multiorgan hamartomas, seizures, and developmental delay. Current consensus recommendations for tuberous sclerosis complex include brain magnetic resonance imaging (MRI) without and with contrast every 1 to 3 years until age 25 years for subependymal giant cell astrocytoma screening, and more often in patients with known subependymal giant cell astrocytoma. Recent reports in the literature regarding gadolinium deposition have prompted us to investigate the added value of intravenous contrast in this setting. Materials and Methods: Thirty-nine MRI examinations from 12 tuberous sclerosis complex patients with known subependymal giant cell astrocytoma were retrospectively reviewed for all caudothalamic groove lesions larger than 1 cm. Lesions were measured in 2 planes on both noncontrast and contrast-enhanced axial 3-dimensional (3D) T1-weighted imaging in a randomized fashion by 2 attending pediatric neuroradiologists. Differences in lesion measurements were compared to zero using a 1-sample t test. Results: On average, radiologist A measured lesions 1.1 mm larger in long-axis diameter without contrast (P = .0003), whereas radiologist B measured lesions 0.1 mm larger without contrast (not significant). Differences in lesion measurement were smaller when comparing noncontrast to contrast-enhanced 3D T1-weighted imaging than when comparing radiologist A to radiologist B. Conclusions: Noncontrast axial 3D T1-weighted imaging is similar to contrast-enhanced axial 3D T1-weighted imaging for subependymal giant cell astrocytoma size measurement. It has high accuracy and may be a safer and more efficient imaging method for tuberous sclerosis complex patients who commonly undergo numerous MRI examinations throughout their lifetime. Further studies may be appropriate to determine whether contrast material could be beneficial in certain situations.