Detection of simulated inflicted metaphyseal fractures in a fetal pig model: image optimization and dose reduction with computed radiography.
OBJECTIVE
To prospectively determine in a fetal pig model whether diagnostic performance comparable to that of high-detail screen-film imaging can be achieved with computed radiography for the detection of simulated classic metaphyseal lesions (CMLs), by using Faxitron digital images as the reference standard, and whether radiation dose reduction is possible.


METHODS
This study was granted exempt status by the institutional review board and the animal care and use committee. Fractures simulating the CML were produced in distal femurs of 20 deceased fetal pigs. Twenty normal femurs served as control femurs. Femurs were imaged with a standard single-side-read 100-microm pixel sampling imaging plate (IP), a high-resolution dual-side-read 50-microm pixel sampling IP, and a high-detail screen-film imaging system. Eight tube current-time product settings (0.5-10.0 mAs) and two tube voltage selections (56 and 70 kVp) were employed. Two pediatric radiologists evaluated 920 images for fracture by using a five-point Likert scale. Area under the receiver operating characteristic curve (A(z)) values for the imaging systems were compared by using nonparametric chi(2) tests (all P < .05).


RESULTS
For pooled rater data, performance of computed radiography was comparable to that of screen-film imaging, and superior performance (P = .04) was achieved with the more experienced rater. The A(z) value tended to increase as the tube current-time product setting was increased. Within each system, there was no significant difference in A(z) values for all images obtained at 56 and 70 kVp (dual-side-read IP, P = .63; single-side-read IP, P = .25; screen-film imaging system, P = .5). At 56 kVp, a dose reduction of up to 69% was achieved, and accuracy of computed radiography was comparable to that of screen-film imaging.


CONCLUSIONS
Findings in this study suggest that computed radiography can replace screen-film imaging in the detection of CMLs and may permit dose reduction.
Kleinman
Patricia L
PL
Department of Radiology, Children's Hospital Boston, 300 Longwood Ave, Boston, MA 02115, USA.
Zurakowski
David
D
Strauss
Keith J
KJ
Cleveland
Robert H
RH
Perez-Rosello
Jeannette M
JM
Nichols
David P
DP
Zou
Kelly H
KH
Kleinman
Paul K
PK
D000818:Animals; D004195:Disease Models, Animal; D005264:Femoral Fractures / Q000000981:diagnostic imaging*; D005333:Fetus; D011446:Prospective Studies; D012372:ROC Curve; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods*; D013552:Swine; D014963:X-Ray Intensifying Screens