MR venography in the pediatric patient

BACKGROUND AND PURPOSE: Little is known about age-related changes in posterior fossa venous anatomy on 2D time-of-flight MR venography (MRV) or about artifacts that limit its accuracy in diagnosing venous occlusive disease. We evaluated pediatric appearances of posterior fossa venous drainage. METHODS: One hundred and eight children with normal MR imaging or minimal congenital anomalies underwent 2D MRV. Transverse sinus dominance and absence and the presence of an occipital sinus were correlated with age. Venous structure conspicuity was compared on source and maximum intensity projection images. RESULTS: Right, left, and codominance of the transverse sinus, respectively, was as follows: at < 25 months, 37%, 21%, and 42%; 25 months to 5 years, 35%, 30%, 35%; and ≥6 years, 50%, 16%, 34%. Transverse sinus dominance was not related to age between the three groups (P = .58, chi-square contingency), but some relationship was observed when patients <6 years were compared to those ≥6 years (P = .032). Chi-square trends showed a mildly positive correlation between age and an absent transverse sinus (P = .026) and a decreasing trend in the presence of an occipital sinus with age (P = .038). Saturation effects due to in-plane/slow flow were worse in patients <25 months; effects in the transverse sinuses or internal jugular veins were miminized with coronal or axial imaging, respectively. CONCLUSION: 2D TOF MRV shows age-related changes in venous anatomy. Caution should be used before posterior fossa venous occlusive disease is diagnosed on the basis of signal intensity loss, especially in neonates and young infants.