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Objective: To investigate orbital vascular resistance by Doppler velocimetry in patients with steady-state sickle cell anemia, as well as to characterize its relationship with biomarkers of hemolysis. Materials and Methods: This was a cross-sectional study of two groups: 71 outpatients with sickle cell anemia; and 32 age- and gendermatched, healthy subjects (control group). All participants underwent Doppler velocimetry of the orbital arteries and laboratory tests. Results: All biochemical laboratory markers were abnormal in the sickle cell anemia patients (p < 0.0001 vs. controls). In the patient group, Doppler velocimetry revealed increased flow velocities in the ophthalmic artery and reduced flow velocities in the central retinal artery, as well as high values for the resistance index (RI) and pulsatility index (PI) in both arteries (p < 0.0001 vs. controls). Biomarkers of hemolysis were found to correlate significantly with the RI and PI indices. In the ophthalmic artery, the reticulocyte count showed a moderate direct correlation with RI and with PI. In the central retinal artery, hemoglobin showed a strong inverse correlation with RI and with PI. Conclusion: Orbital vascular resistance, as evaluated by Doppler velocimetry, is elevated in patients with steady-state sickle cell anemia and shows a significant correlation with biomarkers of hemolysis. [ABSTRACT FROM AUTHOR]

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Copyright of Radiologia Brasileira is the property of Radiologia Brasileira and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To identify predictive variables of iron overload in patients with sickle cell anemia, correlating biochemical and imaging markers. Materials and Methods: The authors developed a cross-sectional study involving 32 patients with sickle cell anemia who were evaluated for ferritin and iron serum levels and submitted to liver magnetic resonance imaging with one spin-echo and five gradient-echo sequences. The signal intensity was obtained at each sequence, corresponding to the arithmetical mean of the measurements on regions of interest in the liver and paraspinal muscles to obtain the liver/muscle signal intensity ratio (SIR). Based on such SIR, the liver iron concentration (LIC) was estimated by means of the following formula: e[5.808 – (0.877 × T2*) – (1.518 × IW)], where T2* is the SIR on the sequence with echo time = 13 ms and IW is the SIR on the intermediate-weighted sequence. Patients were grouped according to their blood transfusion regimen (regular monthly versus sporadic transfusions). Results: The comparison between the transfusion groups was based on clinical-laboratory variables, with significant differences in SIR, LIC and serum ferritin levels: the group with regular transfusions demonstrated greater hepatic iron overload. Conclusion: Magnetic resonance imaging is an efficient tool for evaluating liver iron overload in patients with sickle cell anemia. [ABSTRACT FROM AUTHOR]