Optimizing diffusion-weighted magnetic resonance imaging for evaluation of lung tumors: A comparison of respiratory triggered and free breathing techniques

Signe Swerkersson; Oscar Grundberg; Karl Kölbeck; Andreas Carlberg; Sven Nyrén; Mikael Skorpil

doi:10.1016/j.ejro.2018.10.003

Optimizing diffusion-weighted magnetic resonance imaging for evaluation of lung tumors: A comparison of respiratory triggered and free breathing techniques

Eur J Radiol Open. 2018 Nov 3:5:189-193. doi: 10.1016/j.ejro.2018.10.003. eCollection 2018.

Authors

Signe Swerkersson¹, Oscar Grundberg², Karl Kölbeck², Andreas Carlberg³, Sven Nyrén⁴, Mikael Skorpil⁵

Affiliations

¹ Department of Radiology, St Göran's Hospital, St Göransplan 1, 11281 Stockholm, Sweden.
² Department of Respiratory Medicine & Allergology, Karolinska University Hospital, 17176 Solna, Sweden.
³ Siemens Healthcare AB, Johanneslundsvägen 12, 194 61 Upplands Väsby, Sweden.
⁴ Department of Thoracic radiology, Karolinska University Hospital, 17176 Solna, Sweden.
⁵ Department of Molecular Medicine and Surgery, Karolinska Institutet, Solnavägen 1, 171 77 Solna, Sweden.

Abstract

Purpose: The aim of this study was to compare respiratory-triggered (RT) and free breathing (FB) diffusion weighted imaging (DWI) techniques regarding apparent diffusion coefficient (ADC) measurements and repeatability in non-squamous non-small cell lung cancer (NSCLC) measuring the total tumor volume.

Material and methods: A total of 57 magnetic resonance imaging (MRI) examinations were analyzed. DWI was obtained by a single-shot spin-echo echo-planar imaging sequence, and for each MRI examination 2 consecutive RT and 2 consecutive FB DWI sequences were performed. Two radiologists independently read the images and made measurements. For each tumor the mean ADC value of the whole tumor volume was calculated. The difference in mean ADCs between FB and RT DWI was evaluated using the paired-sample t-test. The repeatability of ADC measurements related to imaging method was evaluated by intra class correlations (ICC) for each of the FB and RT DWI pairs.

Results: There were no significant differences in mean ADCs between FB and RT (Reader 1 p = 0.346, Reader 2 p = 0.583). The overall repeatability of ADC measurement was good for both acquisition methods, with ICCs > 0.9. Subgroup analysis showed somewhat poorer repeatability in small tumors (50 ml or less) and tumors in the lower lung zones for the RT acquisition, with ICC as low as 0.72.

Conclusions: No difference in ADC measurement or repeatability between FB and RT DWI in whole lesion ADC measurements of adenocarcinomas in the lung was demonstrated. The results imply that in this setting the FB acquisition method is accurate and possibly more robust than the RT acquisition technique.

Keywords: ADC, apparent diffusion coefficient; BH, breath-hold; DWI, diffusion weighted imaging; Diffusion weighted imaging; FB, free breathing; ICC, intra class correlations; MRI, magnetic resonance imaging; Magnetic resonance imaging; NSCLC, non-squamous non-small cell lung cancer; ROI, region of interest; RT, respiratory-triggered; SNR, signal-to-noise ratio; non-Small cell lung cancer.