Functional evaluation of emphysema using diffusion-weighted 3Helium-magnetic resonance imaging, high-resolution computed tomography, and lung function tests.
OBJECTIVE
To assess the emphysematous enlargement of distal airspaces and concomitant large and small airway disease using diffusion-weighted Helium-magnetic resonance imaging (MRI), high-resolution computed tomography (HRCT), and lung function tests (LFT).


METHODS
Seven patients were examined after single lung transplantation (LTx) and 1 before double LTx for various forms of emphysema. Five patients after double LTx served as controls. Patients were assessed by Helium-MRI (apparent diffusion coefficient [ADC]), HRCT (mean lung density [MLD], emphysema index [EI]), and LFT.


RESULTS
Transplanted lungs: mean ADC = 0.17 cm/s, MLD = -848 H, EI = 22%. Emphysematous lungs: mean ADC = 0.33 cm/s, MLD = -922 H; EI = 54%. Good correlations were found between ADC and MLD (r = 0.6), EI (r = 0.8), intrathoracic gas volume (r = 0.7), forced expiratory volume in 1 second (r = 0.7), and forced expiratory flows (r = 0.7). In contrast, HRCT only provided moderate correlations with LFT (EI: r = 0.5; MLD: r [le] 0.4).


CONCLUSIONS
In this initial study, He-MRI yield good correlations with HRCT and agrees better than HRCT with the functional characterization of emphysema regarding hyperinflation, large and small airway disease as provided by LFT.
Ley
Sebastian
S
Department of Radiology, Johannes Gutenberg-University, Mainz, Germany. ley@gmx.net
Zaporozhan
Julia
J
Morbach
Andreas
A
Eberle
Balthasar
B
Gast
Klaus Kurt
KK
Heussel
Claus Peter
CP
Biedermann
Alexander
A
Mayer
Eckhard
E
Schmiedeskamp
Joerg
J
Stepniak
Andreas
A
Schreiber
Wolfgang G
WG
Kauczor
Hans-Ulrich
HU
D005260:Female; D006371:Helium; D006801:Humans; D007554:Isotopes; D016040:Lung Transplantation; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011656:Pulmonary Emphysema / Q000503:physiopathology*; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed / Q000379:methods*
D007554:Isotopes; D006371:Helium