The Chrispin-Norman score in cystic fibrosis: doing away with the lateral view

The Chrispin-Norman chest radiograph scoring (CNS) system is widely used to assess respiratory disease progression in cystic fibrosis (CF). Frontal and lateral chest radiographs were performed. The present authors developed a modified CNS, which obviates the need for the lateral film. This study compares the original and the current authors' modified scoring system. A total of 50 chest radiographs from CF children, taken between August and December 2003, were scored according to the original and modified CNS. Two observers scored all 50 chest radiographs, scoring in random order the frontal radiographs, and separately the frontal and lateral radiographs together. There was no evidence of a difference between the methods for either observer, using the Bland and Altman 95% limits of agreement as follows: observer 1 (-2.0-1.9), and observer 2 (-1.77-2.2). No evidence of a difference between the observers for either method was found, comparing the 95% limits of agreement (-5.5-5.7) with the modified CNS (-5.6-6.4). In conclusion, in terms of the final score, good agreement was found between the use of the original and modified Chrispin-Norman score. In addition, low inter-observer variability was shown for both methods. The use of the modified Chrispin-Norman chest radiograph scoring system to stage disease severity in cystic fibrosis removes the need for a lateral chest radiograph.