Side lobes and grating lobes are both unwanted parts of the ultrasound
beam emitted off axis that produce image artifacts due to error in po
sitioning the returning echo, The purpose of this study was to reprodu
ce artifacts associated with side lobes and grating lobes in vitro usi
ng different transducer types and recognize these artifacts in vivo. A
phantom, composed of a water bath, a metallic wire, and a wooden tong
ue depressor, was imaged using a linear array, a curved linear array,
a vector array, and a sector mechanical transducer, When imaging the m
etallic wire in a transverse plane, an echogenic artifact was constant
ly seen on each side of the wire, with a shape and intensity variable
with the transducer type, The artifact was curvilinear and concave (li
near and curved linear arrays), or curvilinear and convex (vector arra
y and the mechanical transducer). When the tongue depressor was imaged
in a longitudinal plane, the artifact was a straight line (linear arr
ay), a curved convex line (curved array), a series of convex curviline
ar echo (vector array) or a small convex curvilinear echo (mechanical
transducer). In vivo situations similar to the phantom experiment were
investigated using clinical patients, Artifacts produced in vitro wer
e recognized in vivo when a highly reflective object (urinary bladder
wall) was imaged adjacent to an anechoic region (urine), These artifac
ts corresponded to the principle of secondary ultrasound lobes, and we
re therefore interpreted as such.