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The cardiothoracic ratio in AGA and SGA very low birth weight newborn infants
L J Wozniak1, S A Hussain, H Goldman
1Department of Pediatrics, Division of Neonatology, Albert Einstein College of Medicine, Jacobi Medical Center, Bronx, NY 10461, USA.
Insights
Very low birth weight (VLBW) infants who are small for gestational age (SGA) have larger cardiothoracic (CT) ratios than appropriate for gestational age (AGA) infants. Current CT ratio standards may not be suitable for SGA infants.
Area of Science:
- Neonatal imaging
- Pediatric cardiology
- Radiographic assessment
Background:
- Cardiothoracic (CT) ratio is a standard measure for heart size in pediatric chest radiographs.
- Recent data on CT ratio standards in very low birth weight (VLBW) infants are lacking.
Purpose of the Study:
- Establish improved CT ratio standards for VLBW infants.
- Compare CT ratios between small for gestational age (SGA) and appropriate for gestational age (AGA) VLBW infants.
Main Methods:
- Retrospective analysis of chest radiographs from 54 VLBW infants (2002-2004).
- Group-matched 18 SGA and 36 AGA infants by birthweight and sex.
- Calculated CT ratios within the first 24 hours of life.
Main Results:
- SGA infants had a significantly greater median gestational age (30 weeks) than AGA infants (27 weeks).
- Mean CT ratio was significantly larger in SGA infants (0.523) compared to AGA infants (0.479).
- No significant differences observed in birthweight, sex, Apgar scores, or intubation status between groups.
Conclusions:
- VLBW SGA infants exhibit larger CT ratios than their AGA counterparts.
- Existing CT ratio standards may be inappropriate for VLBW SGA infants.
- Further research is needed to refine CT ratio interpretation in this population.
Background:
Cardiothoracic (CT) ratio is a common measurement used to assess heart size in chest radiographs of pediatric patients, but no recent studies have analyzed the standards for CT ratios in very low birth weight (VLBW) infants.
Objective:
The aim of this study was to provide improved standards for CT ratios measured from chest radiographs of VLBW (<1500 g) infants, and to compare CT ratios between small for gestational age (SGA) and appropriate for gestational age (AGA) infants in this population.
Design/Methods:
Among VLBW infants admitted to the Jacobi Medical Center NICU from 2002 to 2004, CT ratios were calculated from anteroposterior supine chest radiographs taken of 54 VLBW infants (18 SGA and 36 AGA group-matched on the basis of birthweight and sex) during the first 24 h of life.
Results:
There were no significant differences between the two groups with respect to birthweight, sex, 1-min Apgar score, 5-min Apgar score, intubation status and degree of inspiration. Median GA of the SGA infants was significantly greater than the AGA infants (30 and 27 weeks, respectively; P<0.001). CT ratios among SGA infants were significantly larger than those among AGAs. Using the widest internal width of the bony thorax, the mean CT ratio among SGA and AGA infants was 0.523 and 0.479, respectively (P=0.00102).
Conclusions:
VLBW SGA infants have larger CT ratios than VLBW AGA infants, suggesting that existing standards for normal CT ratios may be inappropriate for use among SGA infants.
