Comparison between the ATS/ERS/JRS/ALAT criteria of 2011 and 2018 for Usual Interstitial Pneumonia on HRCT: a cross-sectional study

Abstract

Objectives: To determine whether the revised 2018 ATS/ERS/JRS/ALAT radiological criteria for usual interstitial pneumonia (UIP) provide better diagnostic agreement compared to the 2011 guidelines.

Methods: Cohort for this cross-sectional study (single center, nonacademic) was recruited from a multidisciplinary team discussion (MDD) from July 2010 until November 2018, with clinical suspicion of fibrosing interstitial lung disease (n= 325). Exclusion criteria were technical HRCT issues, known connective tissue disease (rheumatoid arthritis, systemic sclerosis, poly-or dermatomyositis), exposure to pulmonary toxins or lack of working diagnosis after MDD. Four readers with varying degrees in HRCT interpretation independently categorized 192 HRCTs, according to both the previous and current ATS/ERS/JRS/ALAT radiological criteria. An inter-rater variability analysis (Gwet's second-order agreement coefficient, AC2) was performed.

Results: The resulting Gwet's AC2 for the 2011 and 2018 ATS/ERS/JRS/ALAT radiological criteria is 0.62 (±0.05) and 0.65 (±0.05), respectively. We report only minor differences in agreement level among the readers. Distribution according to the 2011 guidelines is as follows: 57.3% 'UIP pattern', 24% 'possible UIP pattern', 18.8% 'inconsistent with UIP pattern' and for the 2018 guidelines: 59.6% 'UIP', 14.5% 'probable UIP', 15.9% 'indeterminate for UIP' and 10% 'alternative diagnosis'.

Conclusions: No statistically significant higher degree of diagnostic agreement is observed when applying the revised 2018 ATS/ERS/JRS/ALAT radiological criteria for UIP compared to those of 2011. The inter-rater variability for categorizing the HRCT patterns is moderate for both classification systems, independent of experience in HRCT interpretation. The major advantage of the current guidelines is the better subdivision in the categories with a lower diagnostic certainty for UIP.

Advances in knowledge: - In 2018, a revision of the 2011 ATS/ERS/JRS/ALAT radiological criteria for UIP was published, part of diagnostic guidelines for idiopathic pulmonary fibrosis.- The inter-rater agreement among radiologist is moderate for both classification systems, without a significantly higher degree of agreement when applying the revised radiological criteria.

Figure 1.

Axial HRCT images demonstrating the diagnostic categories according to the ATS/ERS/JRS/ALAT radiological criteria of 2011 (examples from the study cohort).

Figure 2.

Axial HRCT images demonstrating the diagnostic categories according to the ATS/ERS/JRS/ALAT radiological criteria of 2018 (examples from the study cohort).

Figure 3.

a) Percentage distribution of the HRCT examinations according to the ATS/ERS/JRS/ALAT radiological criteria of 2011. (1) UIP pattern, (2) possible UIP pattern, (3) inconsistent with UIP pattern. b) Percentage distribution of the HRCT examinations according to the ATS/ERS/JRS/ALAT radiological criteria of 2018. (1) UIP, (2) probable UIP, (3) indeterminate for UIP, (3a) early indeterminate UIP pattern (3b) truly indeterminate for UIP, (4) alternative diagnosis.

Figure 4.

Schematic representation of the redistribution of the HRCT patterns, demonstrating the evolution from each diagnostic category from 2011, and the absolute reallocation according to the 2018 ATS/ERS/JRS/ALAT guidelines. Column 1: (1) UIP pattern, (2) possible UIP pattern, (3) inconsistent with UIP pattern. Column 2 and 3: (1) UIP, (2) probable UIP, (3a) early indeterminate UIP pattern, (3b) truly indeterminate for UIP, (4) alternative diagnosis.

Figure 5.

Thin-section CT images showing subpleural reticular abnormalities, traction bronchiectasis and honeycombing, in a diffuse distribution pattern, which is more pronounced in the middle lung areas. This patient was scored by two readers as ‘inconsistent with UIP’ according to the guidelines of 2011, and as ‘UIP’ according to current guidelines.

Figure 6.

Top row: ‘Early indeterminate UIP pattern’. HRCT with subpleural reticulation, peripheral in the lower lobes. Bottom Row: ‘Probable UIP’. HRCT with subpleural reticulation, peripheral traction bronchiectasis and mild ground-glass opacity. No honeycombing. Both studies were classified as ‘possible UIP’ according to the 2011 guidelines.