Welcome to Classifications and Online Calculators in Radiology

This site was build along with the Atlas of Radiology Images to support your knowledge in radiology.

You will find here:

that are used in radiology and related fields with free access.


  • Some pages are accompanied by illustrations
  • All pages contain tags for easy navigation

The concept

The concept of this website is based on a previous site that was founded in 2008 and is still up and running. The website is composed as a book, where all sources are properly referenced, according to a good practice in scientific publications.

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    Gastroesophageal reflux - grading on barium study

    In 1977, a grading system of gastroesophageal reflux on barium study was devised. It is based on the extent of retrograde flow of barium.

    Grade Description
    I reflux into distal esophagus only
    II reflux extending above carina
    III reflux into cervical esophagus
    IV free persistent reflux into cervical esopagus with a wide open cardia (chalasia)
    V reflux of barium with aspiration into the trachea or lungs
    D delayed reflux - barium is seen in esophagus on delayed films


    1. McCauley RG, Darling DB, Leonidas JC, Schwartz AM. Gastroesophageal reflux in infants and children: a useful classification and reliable physiologic technique for its demonstration. American Journal of Roentgenology 1978;130(1), 47-50.

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