Automated Multiplanar Imaging

Abbreviations AMI, automated multiplanar imaging; 3D; 3-dimensional; 2D, 2-dimensional nlike computed tomography and magnetic resonance imaging, ultrasonography is an operator-dependent imaging modality. Two-dimensional (2D) ultrasonographic images are obtained by manual positioning of the transducer, and the quality of such images is dependent on the technical skills and expertise of the sonographers and sonologists performing the ultrasound examinations. This manual process of generating images in 2D ultrasonography results in a lack of standardization and consistency of diagnosis. Furthermore, the variable position of the fetus within the uterus adds some technical difficulty to obstetric ultrasonography. Several studies have documented that the efficacy of obstetric ultrasonography, especially with regard to the detection of fetal abnormalities, is dependent on the expertise of the operator, and a significant difference in the detection of fetal abnormalities has been reported between tertiary and non–tertiary care centers.1–4 For anatomically complex organs, such as the fetal heart, detection of congenital abnormalities has been suboptimal in population-based studies.1,5–8 It is generally thought that many women in the United States today receive an obstetric ultrasound examination that is considerably lower in standards than currently recommended by various professional societies.9,10 The recent introduction of 3-dimensional (3D) ultrasonography to clinical practice provided an important advance in imaging technology. With 3D ultrasonography, an infinite number of 2D planes of a target volume are acquired. The volume acquired by 3D ultrasonography can be displayed on a monitor in 3 orthogonal planes, representing the sagittal, transverse, and coronal planes of a representative 2D plane within this volume (Figure 1). Such a display of 3 orthogonal planes from a 3D volume acquisition is termed a multiplanar display. The multiplanar display of 3D ultrasonographic volumes enables an operator to manipulate the acquired target volume to create and display reconstructed planes within this volume. Despite these recent advances in ultrasonographic imaging, the acquisition, display, and manipulation of 3D volumes is a technique that requires a substantial learning curve. Even for well-trained personnel, 3D volume manipulation can be diffi-