Comparison of Fetal Head Circumference Measurements Using Standard and Long Linear-Array Transducers

The authors compared relative fetal head circumference measurements between 8- and 12-cm 3.5-MHz lineararray transducers in a sonographic system that can generate a computed ellipse. The head circumference obtained from the 12-cm transducer was employed as the standard against which the 8-cm transducer was compared. Employing the computer-generated ellipse, the authors accurately predicted head circumference with the 8-cm transducer despite the transducer's inability to visualize the entire calvarial perimeter in any case.