{{Short description|Medical ratio}} thumb|A CT scan showing a 3.58 index The '''Haller index''', created in 1987 by J. Alex Haller, S. S. Kramer, and S. A. Lietman,<ref>{{cite journal | vauthors = Haller JA, Kramer SS, Lietman SA | title = Use of CT scans in selection of patients for pectus excavatum surgery: a preliminary report | journal = Journal of Pediatric Surgery | volume = 22 | issue = 10 | pages = 904–6 | date = October 1987 | pmid = 3681619 | doi = 10.1016/s0022-3468(87)80585-7 }}</ref> 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).<ref>{{cite web|url=http://www.scielo.br/pdf/jbpneu/v30n6/en_a03v30n6.pdf|title=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}}</ref>
:<math>\ 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.<ref>{{cite journal | vauthors = Khanna G, Jaju A, Don S, Keys T, Hildebolt CF | title = Comparison of Haller index values calculated with chest radiographs versus CT for pectus excavatum evaluation | journal = Pediatric Radiology | volume = 40 | issue = 11 | pages = 1763–7 | date = November 2010 | pmid = 20473605 | doi = 10.1007/s00247-010-1681-z | s2cid = 23984787 }}</ref><ref>{{cite journal | vauthors = Poston PM, McHugh MA, Rossi NO, Patel SS, Rajput M, Turek JW | title = The case for using the correction index obtained from chest radiography for evaluation of pectus excavatum | journal = Journal of Pediatric Surgery | volume = 50 | issue = 11 | pages = 1940–4 | date = November 2015 | pmid = 26235532 | doi = 10.1016/j.jpedsurg.2015.06.017 }}</ref><ref>{{cite journal | vauthors = Mueller C, Saint-Vil D, Bouchard S | title = Chest x-ray as a primary modality for preoperative imaging of pectus excavatum | journal = Journal of Pediatric Surgery | volume = 43 | issue = 1 | pages = 71–3 | date = January 2008 | pmid = 18206458 | doi = 10.1016/j.jpedsurg.2007.09.023 }}</ref>
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.<ref>{{cite news|url=http://findarticles.com/p/articles/mi_m0FSL/is_6_74/ai_81218971|title=Haller ranges | work=AORN Journal | vauthors = Swoveland B | year=2001}}</ref><ref>{{cite web|url=http://pigeonchestproblems.com/pigeon-chest-stuff/haller-index/|title=Haller Index. Pigeon Chest Problems|year=2015|access-date=2016-10-19|archive-url=https://web.archive.org/web/20180330082310/http://pigeonchestproblems.com/pigeon-chest-stuff/haller-index/|archive-date=2018-03-30|url-status=dead}}</ref> In severe asymmetric cases, where the sternum dips below the level of the vertebra, the index can be a negative value.<ref>{{cite journal | vauthors = Dore M, Triana Junco P, De La Torre C, Vilanova-Sánchez A, Bret M, Gonzalez G, Nuñez Cerezo V, Jimenez Gomez J, Luis Encinas J, Hernandez F, Martínez Martínez L, Lopez Santamaria M | display-authors = 6 | title = Nuss Procedure for a Patient with Negative Haller Index | journal = European Journal of Pediatric Surgery Reports | volume = 6 | issue = 1 | pages = e18–e22 | date = January 2018 | pmid = 29473012 | pmc = 5820059 | doi = 10.1055/s-0038-1623537 }}</ref>
== See also == *Pectus carinatum *Nuss procedure
==Sources== {{Reflist}}
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