Hyperpolarized 3He apparent diffusion coefficient MRI of the lung: reproducibility and volume dependency in healthy volunteers and patients with emphysema.
OBJECTIVE
To measure the apparent diffusion coefficient (ADC) of hyperpolarized (HP) (3)He gas using diffusion weighted MRI in healthy volunteers and patients with emphysema and examine the reproducibility and volume dependency.


METHODS
A total of eight healthy volunteers and 16 patients with emphysema were examined after inhalation of HP (3)He gas mixed with nitrogen (N(2)) during breathhold starting from functional residual capacity (FRC) in supine position. Coronal diffusion-sensitized MR images were acquired. Each subject was imaged on three separate days over a seven-day period and received two different volumes (6% and 15% of total lung capacity [TLC]) of HP (3)He each day. ADC maps and histograms were calculated. The mean and standard deviation (SD) of the ADC at different days and volumes were compared.


RESULTS
The reproducibility of the mean ADC and SD over several days was good in both healthy volunteers and patients (SD range of 0.003-0.013 cm(2)/second and 0.001-0.009 cm(2)/second at 6% and 15% of TLC for healthy volunteers, and a SD range of 0.001-0.041 cm(2)/second and 0.001-0.011 cm(2)/second, respectively, for patients). A minor but significant increase in mean ADC with increased inhaled gas volume was observed in both groups.


CONCLUSIONS
Mean ADC and SD of HP (3)He MRI is reproducible and discriminates well between healthy controls and patients with emphysema at the higher gas volume. This method is robust and may be useful to gain new insights into the pathophysiology and course of emphysema.
Diaz
Sandra
S
Department of Radiology, Malmö University Hospital, Malmö, Sweden. Sandra.diaz@med.lu.se
Casselbrant
Ingrid
I
Piitulainen
Eeva
E
Pettersson
Goran
G
Magnusson
Peter
P
Peterson
Barry
B
Wollmer
Per
P
Leander
Peter
P
Ekberg
Olle
O
Akeson
Per
P
D000328:Adult; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005541:Forced Expiratory Volume; D006371:Helium / Q000008:administration & dosage; D006801:Humans; D007554:Isotopes; D008168:Lung / Q000033:anatomy & histology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology; D011656:Pulmonary Emphysema / Q000503:physiopathology*; D015203:Reproducibility of Results; D014797:Vital Capacity
D007554:Isotopes; D006371:Helium