Validity of apparent diffusion coefficient hyperpolarized 3He-MRI using MSCT and pulmonary function tests as references.
OBJECTIVE
To compare apparent diffusion coefficient (ADC) measurements from hyperpolarized (HP) helium ((3)He)-magnetic resonance imaging (MRI) with quantitative data from multislice Computed Tomography (CT) (MSCT) of the whole lungs and pulmonary function tests (PFT).


METHODS
Twenty-seven subjects, 22 with established emphysema and 5 with preclinical emphysema defined by PFT criteria, were examined with HP (3)He-MRI and MSCT. Mean age was 55 (+/-12) years, 18 female and 9 male. Mean ADC from (3)He-MRI was compared with emphysema index (EI), 15th percentile and mean lung density (MLD) values from MSCT. Both mean ADC and MSCT data were compared to PFT, especially percent of predicted diffusing capacity of carbon monoxide (%predicted DLCO), using Pearson's correlation test.


RESULTS
Mean ADC and standard deviation values were 0.392+/-0.119 cm(2)/s for the established emphysema group and 0.216+/-0.046 for the pre-clinical emphysema group. MSCT values for the established emphysema group and pre-clinical emphysema group were: EI (%) 11+/-12 and 0.4+/-0.6, respectively; 15th percentile (Hounsfield Units (HU)), -956+/-25 and -933+/-13, respectively and MLD (HU) -877+/-20 and -863+/-15, respectively. Correlations between mean ADC and EI and 15th percentile were both r=0.90 and for MLD r=0.59. There was higher correlation between mean ADC and %predicted DLCO (r=0.90) than between EI and %predicted DLCO (r=0.76).


CONCLUSIONS
HP (3)He-MRI correlates well with density measurements from MSCT and agrees better than MSCT with %predicted DLCO which is the PFT most related to emphysema.
Department of Radiology, Malmö University Hospital, Malmö, Sweden. Sandra.diaz@med.lu.se
Sandra
S
Diaz
Ingrid
I
Casselbrant
Eeva
E
Piitulainen
Peter
P
Magnusson
Barry
B
Peterson
Per
P
Wollmer
Peter
P
Leander
Olle
O
Ekberg
Per
P
Akeson
D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006371:Helium; D006801:Humans; D007554:Isotopes; D008297:Male; D008875:Middle Aged; D011656:Pulmonary Emphysema / Q000175:diagnosis*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; D007554:Isotopes; D019275:Radiopharmaceuticals; D006371:Helium