Intra and interobserver reliability and agreement of semiquantitative vertebral fracture assessment on chest computed tomography.
OBJECTIVE
To evaluate the reliability of semiquantitative Vertebral Fracture Assessment (VFA) on chest Computed Tomography (CT).


METHODS
Four observers performed VFA twice upon sagittal reconstructions of 50 routine clinical chest CTs. Intra- and interobserver agreement (absolute agreement or 95% Limits of Agreement) and reliability (Cohen's kappa or intraclass correlation coefficient(ICC)) were calculated for the visual VFA measures (fracture present, worst fracture grade, cumulative fracture grade on patient level) and for percentage height loss of each fractured vertebra compared to the adjacent vertebrae.


RESULTS
Observers classified 24-38% patients as having at least one vertebral fracture, giving rise to kappa's of 0.73-0.84 (intraobserver) and 0.56-0.81 (interobserver). For worst fracture grade we found good intraobserver (76-88%) and interobserver (74-88%) agreement, and excellent reliability with square-weighted kappa's of 0.84-0.90 (intraobserver) and 0.84-0.94 (interobserver). For cumulative fracture grade the 95% Limits of Agreement were maximally ±1,99 (intraobserver) and ±2,69 (interobserver) and the reliability (ICC) varied from 0.84-0.94 (intraobserver) and 0.74-0.94 (interobserver). For percentage height-loss on a vertebral level the 95% Limits of Agreement were maximally ±11,75% (intraobserver) and ±12,53% (interobserver). The ICC was 0.59-0.90 (intraobserver) and 0.53-0-82 (interobserver). Further investigation is needed to evaluate the prognostic value of this approach.


CONCLUSIONS
In conclusion, these results demonstrate acceptable reproducibility of VFA on CT.
Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht, Utrecht, The Netherlands.
Constantinus F
CF
Buckens
Pim A
PA
de Jong
Christian
C
Mol
Eric
E
Bakker
Hein P
HP
Stallman
Willem P
WP
Mali
Yolanda
Y
van der Graaf
Helena M
HM
Verkooijen
D000368:Aged; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D013902:Radiography, Thoracic / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D016103:Spinal Fractures / Q000000981:diagnostic imaging* / Q000453:epidemiology; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries*; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000706:statistics & numerical data