Neonatal Chest Radiography

Introduction

Chest radiography with the portable X-ray unit is the most commonly requested X-ray examination in the neonatal unit. Achieving high quality images can be deceptively difficult. This page examines the issues and techniques peculiar to radiography in the neonatal unit.

Abbreviations and Terminology

UAC: Umbilical artery catheter
UVC: Umbilical vein catheter
ETT: Endotracheal tube
NGT: Nasogastric tube
TPT: Transpyloric tube
VP Shunt: Ventriculo-peritoneal shunt
CVC: Central Venous Catheter
VLBW: Very Low Birthweight
NEC: Necrotising Enterocolitis

Ground Rules

You learn quickly that radiography in the neonatal unit is different. The patients are very small, vulnerable and sometimes very ill. The following are some very simple dot point tips:

• wash your hands before entering the unit and on exiting. Also, wash your hands between babies (important)
• ensure that the baby's name matches the one on the request form (careful you don't get confused with twins)
  
• check the clinical information on the request form- this can influence what you include on the image
  
• don't run the mobile machine into the cot/incubator (surprisingly easy to do)
• ask the nurses for help- they know the babies, know their illnesses, and are skilled in handling them
• be careful to avoid patient rotation, particularly with chest radiography
• use a side marker (see Baker Cone)- left and right are not always clear from the anatomy, particularly in chest radiography
• check departmental protocol re removal of ECG leads
• think about radiation protection- horizontal ray technique considerations, gonad protection, long bone protection, the nurses fingers
  
• you are not the boss- if the nurse says the baby can't be moved..the baby can't be moved.
• use a cassette tray if there is one built into the cot/isolette
  

The Patients

The neonatal unit patients are small- this doesn't make the job easier...in many respects it makes the job harder. The multitude of attachments is also a challenge. The attachments seem to dominate the baby.



Radiation Protection

Operator Irradiation

The person holding the baby can receive an undesirable bonus image of their fingers. This is largely avoided by education, X-ray beam collimation and diligence. The nurse holding the baby may not be as aware of the significance of her fingers in the LBD light as you are.

Operator's Hands I

This is a non-digital film-screen radiograph. There are a number of issues with this image The operator's hands are covering the upper half of the chest no side marker Pre-processing film scratches in lower half of image

Operator's Hands II

The artifact in the RLQ is the umbilicus and umbilical cord clamp <a class="external" href="http://pregnancy.about.com/od/newbornbabies/ss/cordcare_2.htm" rel="nofollow" target="_blank">http://pregnancy.about.com/od/newbornbabies/ss/cordcare_2.htm</a>

This image is circa 1966 with manual processing. Note the characteristic rounded corners of the film. There are several valid criticisms/observations that can be levelled at this radiograph there is only one cone mark visible the operator's fingers are in the image the top artifact (white arrow) is probably a perspex head box (for O2 therapy)...see below there is a circular artifact that is produced by a hole in the perspex of the isolette (lower white arrow). <a class="external" href="http://www.flickr.com/photos/71774835@N00/94691534/" rel="nofollow" target="_blank">http://www.flickr.com/photos/71774835@N00/94691534/</a>

Coning I

This image is circa 1961. Once again it is taken using film/screen technology and manual processing. Note the following there are no cone marks The "R" at the end of the ID number should be on the patient's right side. Tension pneumperitoneum noted

Coning II

This image is circa 1970s. I suspect it is a chest X-ray and the coning is awful. Note also endotracheal tube down right main bronchus atelectasis left lung skin fold over left lung

Coning III

This image is more contemporary. Baby's chests are often vaguely triangle shaped. Using Baker Cones allows the radiographer to shape the beam to the baby's chest shape. This coning may be too tight for some centres that require more of the baby's upper airway to be included in the image.

Radiographic Technique

Side Markers

Side markers in the neonatal unit are important. The difficulty is that your side marker can appear to be almost as big as the baby's chest. There are two solutions that I am aware of Baker Cones Baker cones are pieces of lead rubber that have the side marker punched into them. Dedicated Neonatal Markers The marker on the left of screen is simply too large for use in the Neonatal Unit. You don't want to collimate out to include this relatively large marker. The marker on the right is the type used by the radiographers at the Adelaide Womens and Childrens Hospital. They also use these small markers with the operator's initials. Importantly, the operator's initials are engraved laterally on the marker- ie to the right on a right marker and to the left on a left marker. This ensures that if the marker is partly collimated off, it is the operator's initials that are collimated off and not the "L" or "R".

Side Markers

You should not rely on your ability to establish which is the correct left-right orientation of the image after it is taken. Pathology and patient rotation can make this very difficult. This patient's faintly visible left ventricle and nasogastric tube help, but what if the patient had situs inversus? The UVC tip has tracked into the liver and there appears to be faint portal venous gas. Air in portal venous branches can be associated with umbilical venous catheter insertion. Inconsequential transient portal venous air can be seen immediately after umbilical venous catheter insertion and should not necessarily be attributed to necrotizing enterocolitis. <a class="external" href="http://www.ajronline.org/cgi/content/full/180/4/1147" rel="nofollow" target="_blank">Alan E. Schlesinger1, Richard M. Braverman1 and Michael A. DiPietro2 </a><a class="external" href="http://www.ajronline.org/cgi/content/full/180/4/1147" rel="nofollow" target="_blank">AJR 2003; 180:1147-1153</a>

Cassette Name Window

If you are not using digital radiography, be aware of the patient name window on the cassette. Placing important anatomy over the name window of the cassette is very easy to do. Check your department protocol regarding the amount of upper airway that you should include on the image. Some centres require all of the baby's upper airway to be included on a chest image The umbilical vein catheter (UVC) tip appears to be in the right jugular vein.

Exposure

This image is overexposed. This problem tends to be masked with CR and DR systems because of their greater exposure latitude. It could be argued that the exposure used demonstrated the kinked NGT.

Skin Folds

This is a non-digital film-screen radiograph. There are a number of issues with this image the projection is apical. Note that the baby's clavicles are projected clear of the ribs. This can be avoided with caudal tube angle or angling the baby/cot head up.Some isolettes have tilting mechanisms built into them. no side marker There are multiple skin folds (white arrows) These can be misinterpreted as a pneumothorax

Rotation

This baby is lying in a slightly LPO position. You need a critical eye to pick up this rotation which may not be obvious at the time of exposure. A folded up cleaning cloth under the left shoulder or some tube angle would help to correct the rotation

Artifacts

	This is check film on a central line placement. The central line is partly obscured by the ECG dot. This image presents the case for removal of ECG dots prior to chest radiography in the neonatal unit.
	This baby has atelectasis of the left lung associated with an ET tube in the RMB. The monitor artifact is partly obscuring the tip of the ETT. There are multiple scratch marks on the film pre-processing

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