Neonatal X-Ray Interpretation Smeeta Sardesai, MD, MS Ed. Associate - - PowerPoint PPT Presentation

Neonatal X-Ray Interpretation

Smeeta Sardesai, MD, MS Ed. Associate Professor of Pediatrics Keck School of Medicine University of Southern California University of Southern California Los Angeles

Why X-Rays are Done?

• X-rays are ordered:

– To assess symptoms of conditions related to the heart or lungs – To check the position of – To check the position of internal devices such as central venous catheters or ETT – To correlate with physical findings

Assessment of the Quality of the Neonatal Chest X-Ray

• Radiographs of the newborn chest must be of a high

quality for accurate interpretation

• The clinician evaluating the newborn chest film must be

able to evaluate rotation, presence of artifacts, technique used, and be able to make an accurate diagnosis

• Knowledgeable (Eyes cannot see what the mind doesn’t know)

• Visualization of dorsal intervertebral spaces through the cardiac

Assessment of the Quality of the Neonatal Chest X-Ray: Normal Findings

• Visualization of dorsal intervertebral spaces through the cardiac

silhouette (film density)

• Chest with trapezoid morphology
• Ribs horizontally disposed and parallel to each other
• Cardiophrenic sinuses well delineated
• Anterior arch of the sixth rib is projected over the diaphragm
• Caudal inclination of anterior costal arcs (adequate centralization)
• Symmetry of bone structures on both sides of the thoracic cage

(correct positioning of the neonate)

• Supraclavicular fossas and superior hemiabdomen included

• Quality is essential for accurate evaluation

– Position – Rotation – Artifact – Penetration/exposure – Penetration/exposure

Good Quality Poor Quality

Position

Normal

• There should be symmetry between the hemithoraces
• The spine should lie in the middle of the chest, bisecting the lung

fields – ability to make relative comparisons

• Rotation causes skewed lung fields and possible misdiagnosis
• Difficult to evaluate ETT and/or line position

Normal

Rotation

• Rotation to the

right makes the heart appear central Rotation to the right Normal Rotation to the Left

• Rotation to the left

makes the heart look large and can make the right heart border disappear

Artifacts

Skin fold at left

Artifacts need to be recognized so that they are not mistaken for pathology

Artifact related to projection of neonatal incubator access port

To differentiate “skin fold” from air leak, trace the outline of the lucency; if it crosses diaphragm or upwards into the neck, it is a skin fold.

Penetration/Exposure

Exposure differences in chest x-rays for two different infants

• The overall appearance is very

white

• The details of the lung fields are

exaggerated due to the exposure

• The vertebral bodies are not clearly

defined

• The soft tissues very apparent
• The details of the lung fields

are lost

• The ribs and vertebral bodies

are very distinct

• The soft tissue is not as

apparent Overexposed Underexposed

Supine expiratory CXR Supine inspiratory CXR

Assessment of Inspiratory Effort

• Methods used by practitioners to assess the degree of inspiration:

Normal

• Methods used by practitioners to assess the degree of inspiration:
• Number of ribs above the diaphragm:
• Diaphragm at or below the eighth rib- normal
• Contour of the diaphragm:
• Over inflation: overly flattened diaphragms
• Under inflation: rounded diaphragms bulging into the lung fields
• Position of the stomach bubble:
• Should be located below the edge of the left diaphragm

Normal Findings

• Radiographically, the thymus is characterized by widening
• f the upper mediastinum, above the cardiac image
• On the frontal view, the normal width of the thymic image

must be higher than the double width of the third thoracic vertebra, shorter dimensions representing a sign of thymic involution. involution.

X-Ray Characteristics of Thymus

Thymic configuration may mimic disease and some signs are useful to identify its normal appearance

In the Spinnaker sail sign, the lobes of the thymus are laterally displaced from mediastinum indicating pneumomediastinum

Spinnaker sail sign Spinnaker sail sign

Assessment of Tubes

Endotracheal Tube

• The tip of Endotracheal tube should be in the trachea approximately

midway between the interclavicular line and the carina. (with baby's head midline).

The most common malpositioning is in the right mainstem bronchus Right mainstem bronchus intubation with atelectasis of the entire left lung.

Endotracheal Tube Misplacement

atelectasis of the entire left lung. Endotracheal tube is positioned in the esophagus Complete collapse of left lung and Rt upper lobe with bronchus intermedius intubation

Assessment of Catheters

Umbilical catheters

Optimal levels

• Umbilical venous catheter:
• At the level of D9 (ICV)
• An intracardiac placement may cause arrhythmias

and even death in case of atrial wall perforation and cardiac tamponade. and cardiac tamponade.

• Umbilical arterial catheter:
• At the level of D6 (D5-D9) or L3-L5
• It's important to avoid the origin of main arterial vessels:
• D12 (level of celiac trunk).
• D12-L1 (level of the superior mesenteric artery, SMA).
• L1-L2 (level of renal arteries).
• L3 (inferior mesenteric artery, IMA).
• L4 (aorto-iliac bifurcation)

Anomalous Position of UVC

Complications Associated With Catheters

Catheters inside an artery or into the portal vein may cause thrombosis or portal cavernomatosis

• Malpositioned catheter should be removed immediately

Other complications include hepatic necrosis, hepatic fluid collections, and hematoma, with the intraparenchymal liver lesions

Anomalous Positions of UAC

Umbilical Catheter Complication

Chest Tube

Thoracostomy Tubes Complications

Thirteen-year-old girl with bilateral breast deformity after multiple pneumothoraces as a neonate and treatment with chest tubes

Pediatrics 2003;111;80-86

Orogastric Tube

Respiratory Distress Syndrome (RDS)

• Classic RDS: thorax is Bell-shaped due to

generalized under-aeration, lung parenchyma has a fine granular pattern, and air bronchograms that extend to the periphery

• Moderately severe RDS: reticulogranular
• Moderately severe RDS: reticulogranular

pattern is more prominent and uniformly distributed than usual. The lungs are hypo- aerated with increased air bronchograms

• Severe RDS: beside the reticulogranular
• pacities and air bronchograms there is total
• bscuration of the cardiac silhouette

Respiratory Problems in Neonates

TTN

• TTN: hyperinflated lungs with retained fluid

within the alveoli, interstitium and right fissure, as well as increased perihilar interstitial markings

• Imaging findings of TTN typically improve

within 24 hours MAS: pulmonary hyperinflation secondary to

TTN

MAS: pulmonary hyperinflation secondary to the ball-valve mechanism of air trapping. Air trapping results in pneumothorax, pneumomediastinum & pulmonary interstitial emphysema. Other findings include perihilar ropey opacities and interspersed areas of atelectasis

Neonatal Pneumonia

• Radiographic presentation of neonatal

pneumonia is frequently nonspecific

• Diffuse reticulonodular densities similar to

RDS or patchy, asymmetric infiltrates with hyperaeration

• Small pleural effusion will be present in 2/3 of

pneumonia (uncommon in RDS) pneumonia (uncommon in RDS) X-rays should be interpreted with full reference to the clinical scenario