Professional
Technical
IVT
lung-to-head ratio
Also written as: LHR
Ultrasound measurement used to assess fetal lung development, particularly in cases of congenital diaphragmatic hernia.
Full Definition
The lung-to-head ratio (LHR) is a prenatal ultrasound measurement that compares the area of the contralateral lung to the head circumference in fetuses with congenital diaphragmatic hernia. This ratio serves as a prognostic indicator for postnatal survival and helps guide decisions regarding fetal intervention. An observed-to-expected LHR less than 25% indicates severe pulmonary hypoplasia and poor prognosis without intervention.
Usage
Usage note: Often abbreviated as LHR in clinical documentation.
In Context
- "The lung-to-head ratio was severely diminished at 0.8, indicating candidacy for fetal intervention." — Prenatal evaluation
- "Serial lung-to-head ratio measurements showed improvement following FETO procedure." — Follow-up assessment
Also known as
LHR
Don't confuse with
total lung volume
pulmonary index