What Does Bilateral Mean in a Radiology Report?

Bilateral in a radiology report means that both sides are affected. There are many parts of the body where we have right and left sides.  For example, we have a right and left lung.  We have a right and left leg.  This can be referred to as bilateral.

Medical definition of Bilateral

When we say bilateral in a radiology report, we mean the abnormality involves both sides of the anatomy.  Many structures and organs in our body have right and left sides.  We can refer to many of these as bilateral.

Brain examples of bilateral

Bilateral can refer to the brain hemispheres.  There can be strokes in bilateral hemispheres of the brain for example.  We can have atrophy or volume loss on both sides of the brain.  Both hemispheres of the brain can have metastasis or spread of cancer.  This would be referred to as bilateral brain metastasis.

Neck examples of bilateral

We can refer to structures in the neck as bilateral.  For example, the bilateral carotid arteries have areas of stenosis or narrowing.  The thyroid gland has right and left lobes which we can refer to as bilateral.   Some structures in the neck like the throat are referred to as right and left sides instead of bilateral.

Lung examples of bilateral

An example in the lungs would be a bilateral pneumonia.  This means both the right and left lungs are involved.  A bilateral pulmonary embolism would mean that both the right and left pulmonary arteries have clots.  Right and left sided ribs can be referred to as bilateral ribs.

Abdomen examples of bilateral

In the abdomen, many of the organs are not referred to as bilateral since they are only found on one side.  The spleen is only on the left and the liver on the right.  The adrenal glands which are above the kidneys are on the right and left and can be referred to as bilateral.

Some organs like the liver have right and left sides or lobes.   Most physicians would not refer to the lobes of the liver as bilateral.  Instead we would say the abnormality involves the right and left lobes.  So bilateral does not always mean involvement of both sides in medical terms.

The abdominal cavity has right and left sides and can be referred to as bilateral.  Some arteries which are found on the right and left sides are referred to as bilateral, like the renal arteries or those which feed the kidneys.

Pelvis examples of bilateral

In the pelvis, we can refer to the right and left ovaries as bilateral. The uterus has right and left sides but we would not refer to them as bilateral.  We can refer to lymph nodes or arteries in the pelvis as bilateral.

Arms and leg examples of bilateral

We also refer to the arms and legs as bilateral extremities.  Upper for arms and lower for legs.  An example would be bilateral clots in the arms and legs.  Bilateral cellulitis in the arms and legs means there is infection on both sides.

Bilateral in normal radiology reports

Bilateral is commonly found in normal and abnormal radiology reports.   In normal reports we may say that the bilateral lungs are clear of abnormality.  Or we may that there is no clot seen in the bilateral lower extremities.

Bilateral is therefore a common way of referring to both sides in a radiology report.  This can be in normal and abnormal reports.  In some cases, we may use right and left sides rather then bilateral. This can mean the same thing.