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Free‐breathing quantification of regional ventilation derived by phase‐resolved functional lung (PREFUL) MRI
Author(s) -
Klimeš F.,
Voskrebenzev A.,
Gutberlet M.,
Kern A.,
Behrendt L.,
Kaireit T.F.,
Czerner C.,
Renne J.,
Wacker F.,
VogelClaussen J.
Publication year - 2019
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.4088
Subject(s) - supine position , ventilation (architecture) , repeatability , nuclear medicine , relaxation (psychology) , prone position , medicine , radiology , mathematics , physics , statistics , thermodynamics
Purpose To test the feasibility of regional fully quantitative ventilation measurement in free breathing derived by phase‐resolved functional lung (PREFUL) MRI in the supine and prone positions. In addition, the influence of T 2 * relaxation time on ventilation quantification is assessed. Methods Twelve healthy volunteers underwent functional MRI at 1.5 T using a 2D triple‐echo spoiled gradient echo sequence allowing for quantitative measurement of T 2 * relaxation time. Minute ventilation (Δ V ) was quantified by conventional fractional ventilation (FV) and the newly introduced regional ventilation ( V R), which corrects volume errors due to image registration. Δ V FV versus Δ V VR and Δ V VR versus Δ V VR with T 2 * correction were compared using Bland–Altman plots and correlation analysis. The repeatability and physiological plausibility of all measurements were tested in the supine and prone positions. Results On global and regional scales a strong correlation was observed between Δ V FV versus Δ V VR and Δ V VR versus Δ V VRT2* ( r > 0.93); however, regional Bland–Altman analysis showed systematic differences ( p < 0.0001). Unlike Δ V VRT2* , Δ V VR and Δ V FV showed expected physiologic anterior–posterior gradients, which decreased in the supine but not in the prone position at second measurement during 3 min in the same position. For all quantification methods a moderate repeatability (coefficient of variation <20%) of ventilation was found. Conclusion A fully quantified regional ventilation measurement using Δ V VR in free breathing is feasible and shows physiologically plausible results. In contrast to conventional Δ V FV, volume errors due to image registration are eliminated with the Δ V VR approach. However, correction for the T 2 * effect remains challenging.