Response to “T2-weighted PROPELLER MRI is not suitable for pulmonary emphysema quantification”

Dear editor,

First of all, we would like to thank the authors of this letter for their interest in our work [1]. The authors state that qualitative assessment of emphysema is known to have poor to moderate agreement based on a CT study on pulmonary emphysema by Smith et al. [2]. However, Smith et al. report substantial to excellent intra-reader agreement for all subtypes of emphysema (centrilobular, paraseptal, panlobular), moderate to substantial inter-reader agreement for centrilobular and paraseptal emphysema (only poor for panlobular emphysema), moderate to excellent reliability of severity for all subtypes for both intra-reader and inter-reader assessment, and substantial inter-reader agreement for predominant emphysema subtypes [2]. Smith et al. also point out that the visual assessment of emphysema on CT is clinical gold standard [2]. For this reason and because Smith et al. did not mention MRI in their study [2], we think that the authors’ statement regarding the poor to moderate agreement is a bit misleading.

• References

• 1 Meier-Schroers M, Sprinkart AM, Becker M. et al. Quantitative and Qualitative Assessment of Pulmonary Emphysema with T2-Weighted PROPELLER MRI in a High-Risk Population Compared to Low-Dose CT. Rofo 2018; 190: 733-739
• 2 Smith BM, Austin JH, Newell JD. et al. Pulmonary Emphysema Subtypes on Computed Tomography in Smokers. Am J Med. 2014; 127: 94.e7-94.e23
• 3 Lynch DA, Al-Qaisi MA. Quantitative computed tomography in chronic obstructive pulmonary disease. J Thorac Imaging 2013; 28: 284-290
• 4 Gierada DS, Pilgram TK, Whiting BR. et al. Comparison of standard- and low-radiation-dose CT for quantification of emphysema. Am J Roentgenol 2007; 188: 42-47
• 5 Roach DJ, Crémillieux Y, Serai SD. et al. Morphological and quantitative evaluation of emphysema in chronic obstructive pulmonary disease patients: A comparative study of MRI with CT. J Magn Reson Imaging 2016; 44: 1656-1663
• 6 Wielpütz M, Kauczor HU. MRI of the lung: state of the art. Diagn Interv Radiol 2012; 18: 344-353