The prone cross-table lateral view is an additional projection to demonstrate the pediatric abdomen and is a more ideal alternative to the invertogram, which may be less comfortable for the patient. This discomfort may result in a continuously crying baby, causing the puborectalis sling to contract, leading to a misleading impression of distal rectal obscuration 1,2.
On this page:
Indications
This view is ideal for indicating the distance between the gas bubble in the terminal colon and the perineal skin, allowing the classification of anal atresia in neonates. The image is often obtained 24 hours after birth, to allow for small fistulas to become apparent.
Patient position
patient is prone in genupectoral position (for a minimum of 3 minutes)
ensure no rotation of hips and shoulders
remove any radiopaque items (e.g. ECG dots, diaper, shiny decorative clothing)
take the x-ray in full inspiration
a radiopaque marker (i.e. a coin) is placed over the expected anus using radiolucent tape
Technical factors
lateral projection
suspended inspiration (on observation)
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centering point
the midcoronal plane at the level of the greater trochanter 1
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collimation
superior to the diaphragm
inferior to the rectum
anteroposterior to include soft tissue edge
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orientation
landscape
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detector size
will vary depending on the child's body habitus
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exposure 3
60-75 kVp
3-10 mAs
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SID
100 cm
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grid
if patient thickness is above 10 cm, use of a grid is advisable 3
Image technical evaluation
it should be possible to determine the distance between the air-filled distal rectal pouch and the anal dimple (marked by a radio-opaque marker)
the abdomen should be free from rotation
no blurring of the bowel gas from respiratory motion is ideal
Lead shielding
Contact lead shielding is no longer recommended for any pediatric examination. Statements have been released by several radiological societies supporting an end to this practice 4-7, with the most comprehensive guidance statement on this matter being in an 86-page joint report 8.
Please see your local department protocols for further clarification as they may differ from these recommendations.
Practical points
Preparing the room beforehand (setting up the detector, exposure and preparing lead gowns) is extremely beneficial as patients may get startled by the movement of loud equipment.
Imaging of neonates whilst they are calm or asleep can allow for a less challenging examination.
Immobilization techniques
To prevent malrotation and/or motion artifact in the radiograph, parental holding at the head and leg of the patient may be required. Placing immobilization devices to ensure the patient is faced down with their hips flexed will allow for increased stability in positioning.