Haller index
The Haller index, created in 1987 by J. Alex Haller, S. S. Kramer, and S. A. Lietman,[1] is a mathematical relationship that exists in a human chest section observed with a CT scan. It is defined as the ratio of the transverse diameter (the horizontal distance of the inside of the ribcage) and the anteroposterior diameter (the shortest distance between the vertebrae and sternum).[2]
- [math]\displaystyle{ \ HI = \frac {\text{distance 1}}{\text{distance 2}} }[/math]
where:
- HI is the Haller Index
- distance 1 is the distance of the inside ribcage (at the level of maximum deformity or at the lower third of the sternum)
- distance 2 is the distance between the sternal notch and vertebrae.
More recent studies show that simple chest x-rays are just as effective as CT scans for calculating the Haller index and recommend replacing CT scans with CXR to reduce radiation exposure in all but gross deformities.[3][4][5]
A normal Haller index should be about 2.5. Chest wall deformities such as pectus excavatum can cause the sternum to invert, thus increasing the index.[6][7] In severe asymmetric cases, where the sternum dips below the level of the vertebra, the index can be a negative value.[8]
See also
- Pectus carinatum
- Nuss procedure
Sources
- ↑ "Use of CT scans in selection of patients for pectus excavatum surgery: a preliminary report". Journal of Pediatric Surgery 22 (10): 904–6. October 1987. doi:10.1016/s0022-3468(87)80585-7. PMID 3681619.
- ↑ "How the Haller is measured. Departament of Cardiology and Pulmonology of the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo – Thoracic Surgery Sector". http://www.scielo.br/pdf/jbpneu/v30n6/en_a03v30n6.pdf.
- ↑ "Comparison of Haller index values calculated with chest radiographs versus CT for pectus excavatum evaluation". Pediatric Radiology 40 (11): 1763–7. November 2010. doi:10.1007/s00247-010-1681-z. PMID 20473605.
- ↑ "The case for using the correction index obtained from chest radiography for evaluation of pectus excavatum". Journal of Pediatric Surgery 50 (11): 1940–4. November 2015. doi:10.1016/j.jpedsurg.2015.06.017. PMID 26235532.
- ↑ "Chest x-ray as a primary modality for preoperative imaging of pectus excavatum". Journal of Pediatric Surgery 43 (1): 71–3. January 2008. doi:10.1016/j.jpedsurg.2007.09.023. PMID 18206458.
- ↑ "Haller ranges". AORN Journal. 2001. http://findarticles.com/p/articles/mi_m0FSL/is_6_74/ai_81218971.
- ↑ "Haller Index. Pigeon Chest Problems". 2015. http://pigeonchestproblems.com/pigeon-chest-stuff/haller-index/.
- ↑ "Nuss Procedure for a Patient with Negative Haller Index". European Journal of Pediatric Surgery Reports 6 (1): e18–e22. January 2018. doi:10.1055/s-0038-1623537. PMID 29473012.
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