Purpose: To establish reference values of the ratios of flow velocity in the middle cerebral artery (VMCA) and the terminal portion of the internal carotid artery (VtICA) to flow velocity in the extracranial portion of internal carotid artery (VICA) in children with sickle cell disease (SCD). Materials and Methods: Institutional ethics committee approval and parental informed consent were obtained for this prospective HIPAA-compliant study. Sixty-eight children (38 female; mean age, 7.7 years ± 3.3; range, 2-14 years) with HbSS genotype, without neurologic deficits and no history of stroke, were enrolled. Final study population comprised 56 (mean age 8.0 ± 3.3 years, 26 females) children who underwent magnetic resonance (MR) angiography, which excluded intracranial arterial narrowing, transcranial color-coded duplex ultrasonography (US), and carotid US to determine VMCA/VICA and VtICA/VICA ratios from angle-corrected and uncorrected velocities. Tolerance interval estimates were used to calculate reference ranges and linear regression was used to quantify associations of Doppler parameters with age adjusted for hemoglobin and hematocrit. Results: Reference ranges in centimeters per second for mean angle-corrected VMCA on the left and right sides were 62-198 and 69-153; those for VtICA were 30-196 and 36-175; and those for VICA were 18-116 and 15-95, respectively. Reference ranges for mean angle-corrected V MCA/VICA ratio on the left and right sides were 1.2-4.0 and 0.4-3.4 and those for VtICA/VICA ratio were 0.5-2.9 and 0.5-2.7, respectively. VMCA, VtICA, and V tICA/VICA ratio were not age dependent, contrary to V ICA and VMCA/VICA ratio, after controlling for hematocrit and hemoglobin. Conclusion: The study provides reference limits for VMCA, VtICA, VICA, and velocity ratios obtained from children with SCD.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging