title: Quantitative computed tomography assessment of transfusional iron overload.
abstract: Quantitative computed tomography (QCT) has been proposed for iron quantification for more than 30 years, however there has been little clinical validation. We compared liver attenuation by QCT with magnetic resonance imaging (MRI)-derived estimates of liver iron concentration (LIC) in 37 patients with transfusional siderosis. MRI and QCT measurements were performed as clinically indicated monitoring of LIC and vertebral bone-density respectively, over a 6-year period. Mean time difference between QCT and MRI studies was 14 d, with 25 studies performed on the same day. For liver attenuation outside the normal range, attenuation values rose linearly with LIC (r(2) = 0·94). However, intersubject variability in intrinsic liver attenuation prevented quantitation of LIC <8 mg/g dry weight of liver, and was the dominant source of measurement uncertainty. Calculated QCT and MRI accuracies were equivalent for LIC values approaching 22 mg/g dry weight, with QCT having superior performance at higher LIC's. Although not suitable for monitoring patients with good iron control, QCT may nonetheless represent a viable technique for liver iron quantitation in patients with moderate to severe iron in regions where MRI resources are limited because of its low cost, availability, and high throughput.
authors.affiliation: Division of Paediatric Cardiology, Department of Paediatrics, Children's Hospital Los Angeles, CA 90027, USA. jwood@chla.usc.edu
authors.forename: John C
authors.initials: JC
authors.lastname: Wood
authors.forename: Ashley
authors.initials: A
authors.lastname: Mo
authors.forename: Aakansha
authors.initials: A
authors.lastname: Gera
authors.forename: Montre
authors.initials: M
authors.lastname: Koh
authors.forename: Thomas
authors.initials: T
authors.lastname: Coates
authors.forename: Vicente
authors.initials: V
authors.lastname: Gilsanz
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007501:Iron / Q000378:metabolism; D019190:Iron Overload / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000209:etiology; D008099:Liver / Q000000981:diagnostic imaging / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods; D065227:Transfusion Reaction; D055815:Young Adult; D017086:beta-Thalassemia / Q000628:therapy
chemical_list: D007501:Iron