Dr. Marco Ha · author and medical reviewer
Paediatric surgery, trauma surgery, hyperbaric and diving medicine · Last medically reviewed
Direct answer
What Haller Index Is Severe? Understanding CT Measurements in Pectus Excavatum
The Haller index helps describe pectus severity, but surgery should not be decided by one number alone. Learn how it is measured and interpreted.
The full guide below explains assessment, options and warning signs. Online information cannot replace an examination.
How is the Haller index calculated?
The Haller index is generally the widest internal transverse chest diameter divided by the shortest distance between the sternum and spine. A deeper depression reduces the anteroposterior diameter and raises the index.
Slice level, breathing phase and chest shape can affect the result, so tiny decimal differences should not be overinterpreted.
Is 3.25 an absolute surgical cutoff?
No. A value around 3.25 is widely used as a severity reference, but it is not an automatic yes-or-no rule. Symptoms, cardiac compression, asymmetry, exercise capacity and psychosocial impact also matter.
What is the correction index?
The correction index estimates the percentage of correction needed to bring the sternum toward an expected position. It can better represent severity in some chest shapes and may complement the Haller index.
Does every child need a CT scan?
No. Imaging should be ordered when it is likely to affect management, while considering radiation exposure. Low-dose protocols or alternative imaging may be used in selected settings.
What can the Haller index answer?
It describes chest proportions on a selected imaging slice and can support communication about anteroposterior narrowing, other imaging findings, research, or coverage rules. It does not directly measure exercise capacity, pain, psychological distress, or guaranteed benefit from surgery.
Check three things before interpreting the number
- Whether CT, MRI, or another method was used and the respiratory phase during imaging.
- Whether depression is eccentric, the sternum is rotated, or the Correction Index adds useful context.
- Whether the image will change observation, nonoperative care, or surgical planning.
What should be reviewed after the number?
For breathlessness, chest pain, or palpitations, use the heart and lung function page. For observation versus surgery, use the criteria page. A value of 3.25 is not a switch between two automatic paths.
Related guide: Imaging indices are only one part of assessment. For the symptoms and findings that may support a surgical evaluation, read Does pectus excavatum always need surgery?
Frequently asked questions
Is a Haller index of 3.0 severe?
The number alone is insufficient; symptoms, chest shape, cardiopulmonary findings and progression matter.
Can breathing change the Haller index?
Yes. Respiratory phase and measurement level can affect the anteroposterior diameter.
References and source topics
Original educational content based on publicly available professional guidance. It does not replace clinical examination.
How sources are selected, reviewed and corrected: medical editorial and source policy.
Pediatric surgery, trauma surgery and hyperbaric medicine. Last updated: October 3, 2026.