title: Quantification of aortic valve calcification using multislice spiral computed tomography: comparison with atomic absorption spectroscopy.
abstract: OBJECTIVE
  Multislice spiral computed tomography (MSCT) allows the in vivo detection of valvular calcification. The aim of this study was to validate the quantification of aortic valve calcification (AVC) by MSCT with in vitro measurements by atomic absorption spectroscopy.
  
  
  METHODS
  In 18 patients with severe aortic stenosis, 16 detector row MSCT (SOMATOM Sensation 16, Siemens, Forchheim, Germany with scan parameters as follows: 420 milliseconds tube rotation time, 12 x 0.75 mm collimation, tube voltage 120 KV) was performed before aortic valve replacement. Images were reconstructed at 60% of the RR interval with an effective slice thickness of 3 mm and a reconstruction increment of 2 mm. AVC was assessed using Agatston AVC score, mass AVC score, and volumetric AVC score. After valve replacement, the calcium content of the excised human stenotic aortic valves was determined in vitro using atomic absorption spectroscopy.
  
  
  RESULTS
  The mean Agatston AVC score was 3,842 +/- 1,790, the mean volumetric AVC score was 3,061 +/- 1,406, and mass AVC score was 888 +/- 492 as quantified by MSCT. Atomic absorption spectroscopy showed a mean true calcification mass (Ca5(PO4)3OH) of 19 +/- 8 mass%. There was a significant correlation between in vivo AVC scores determined by MSCT and in vitro mean true calcification mass (r = 0.74, P = 0.0004 for mass AVC score, r = 0.79, P = 0.0001 for volumetric AVC score and r = 0.80, P = 0.0001 for Agatston AVC score) determined by atomic absorption spectroscopy. Linear regression analysis showed a significant association between the degree of hydroxyapatite (given in mass%) in the aortic valve and the degree of AVC (R = 0.74, F = 19.6, P = 0.0004 for mass AVC score, R = 0.80, F = 29.3, P = 0.0001 for Agatston AVC score and R = 0.79, F = 27.3, P = 0.0001 for volumetric AVC score) assessed by MSCT.
  
  
  CONCLUSIONS
  MSCT allows accurate in vivo quantification of aortic valve calcifications.
authors.affiliation: Department of Cardiology, University Hospital RWTH Aachen, Germany. rkoos@ukaachen.de
authors.forename: Ralf
authors.initials: R
authors.lastname: Koos
authors.forename: Andreas Horst
authors.initials: AH
authors.lastname: Mahnken
authors.forename: Harald Peter
authors.initials: HP
authors.lastname: Kühl
authors.forename: Georg
authors.initials: G
authors.lastname: Mühlenbruch
authors.forename: Vera
authors.initials: V
authors.lastname: Mevissen
authors.forename: Ludwig
authors.initials: L
authors.lastname: Stork
authors.forename: Richard
authors.initials: R
authors.lastname: Dronskowski
authors.forename: Georg
authors.initials: G
authors.lastname: Langebartels
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Autschbach
authors.forename: Jan R
authors.initials: JR
authors.lastname: Ortlepp
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000737:chemistry / Q000000981:diagnostic imaging; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000473:pathology; D002114:Calcinosis / Q000000981:diagnostic imaging* / Q000473:pathology; D017886:Durapatite / Q000032:analysis; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D012720:Severity of Illness Index; D013054:Spectrophotometry, Atomic; D036542:Tomography, Spiral Computed
chemical_list: D017886:Durapatite