Myth #4: “A clear X-ray means the lesion is gone”

Fact: A normal (or “clear”) chest X-ray does not reliably rule out a congenital lung malformation.

Many CLMs can be hard to see on an X-ray, especially if a baby is breathing well and the area isn’t causing obvious changes. A newborn chest X-ray is mainly a quick safety check. A normal X-ray can be reassuring about how baby is doing right now, but it doesn’t reliably rule out a congenital lung malformation. That’s why a CT scan is used to confirm what’s actually happening and to understand the size, location, and blood supply. The CT scan is normally recommended a few months after birth unless the baby is symptomatic, in which case it will need to happen sooner.

Why a CLM might not show up on an X-ray:

• X-rays have limited contrast for soft tissues.
  An X-ray works by showing differences in how much tissues absorb radiation. Bone looks bright because it blocks a lot, air looks dark because it blocks very little. Most lung issues only show up if they change the balance of air vs tissue enough to create a clear pattern. Many CLMs don’t do that in an obvious way, especially when a baby is otherwise well.

• Some lesions are “invisible” when they’re fluid-filled or not air-trapping yet.
  A lot of CLMs are detected on prenatal ultrasound because they look bright (echogenic) or cystic in that context. After birth, those same areas may still be fluid-filled, partially collapsed, or just not behaving differently enough from surrounding lung to stand out on a plain X-ray.

• Small lesions and certain locations are easy to miss.
  If the lesion is small, deep, behind the heart/diaphragm, or overlapping other structures, the X-ray may look “normal” because everything is layered on top of everything else in a 2D image.

• A normal X-ray can reflect “baby is stable,” not “nothing is there.”
  Chest X-ray is great for big, obvious changes (collapsed lung, infection, big air pockets, major shift of structures). It’s not great for confidently ruling out a congenital lesion that was seen prenatally.

So why do doctors do a chest X-ray right after birth?

1. To check how baby is doing right now.
   Right after birth, the priority for a baby with a known or suspected lung lesion is: is the baby breathing comfortably and are the lungs inflating normally? A chest X-ray can quickly show very serious issues like a collapsed area of lung, a large air pocket, trapped air, fluid, pneumonia, or a shift of the heart/mediastinum that might explain breathing distress.

2. To look for complications that need urgent action.
   If a lesion is large or acting like a one-way valve (air trapping), it can sometimes cause over-inflation and push on other structures. An X-ray is a rapid first check for anything that would change immediate management.

3. Baseline imaging.
   Even if it doesn’t “prove” the CLM, it gives a starting point to compare against later images if symptoms develop (like respiratory distress, fever, or recurrent infections).

4. It’s the easiest first-line test in a newborn setting.
   CT is more detailed, but it’s not usually done right away because it’s higher radiation, often needs careful timing, and depending on age/center may involve sedation or very controlled conditions. So X-ray is a sensible first step when the question is “is there anything urgent happening today?”

   
   An X-ray is a simpler, lower-detail picture. It can miss smaller lesions or ones that blend in with normal lung tissue. A CT scan gives the detailed view doctors need to make informed decisions about monitoring vs surgery, and to plan safely if surgery is recommended. If you’ve been told “the X-ray looks fine,” that can be reassuring about breathing right now, but it isn’t the final word on whether a CLM is actually present. If you’re unsure what imaging is planned, it’s completely reasonable to ask your care team: “What study will confirm the diagnosis?”