In:
Journal of Applied Physiology, American Physiological Society, Vol. 110, No. 1 ( 2011-01), p. 225-235
Abstract:
Regional and global relationships of lung function and structure were studied using hyperpolarized 3 He MRI in a rat elastase-induced model of emphysema ( n = 4) and healthy controls ( n = 5). Fractional ventilation ( r) and apparent diffusion coefficient (ADC) of 3 He were measured at a submillimeter planar resolution in ventral, middle, and dorsal slices 6 mo after model induction. Pulmonary function testing (PFT) was performed before MRI to yield forced expiratory volume in 50 ms (FEV 50 ), airway resistance (R I ), and dynamic compliance (C dyn ). Cutoff threshold values of ventilation and diffusion, r* and ADC*, were computed corresponding to 80% population of pixels falling above or below each threshold value, respectively. For correlation analysis, r* was compared with FEV 50 /functional residual capacity (FRC), R I and C dyn , whereas ADC* was compared with FEV 50 /FRC, total lung capacity (TLC), and C dyn . Regional correlation of r and ADC was evaluated by dividing each of the three lung slices into four quadrants. C dyn was significantly larger in elastase rats (0.92 ± 0.16 vs. 0.61 ± 0.12 ml/cmH 2 O). The difference of R I and FEV 50 was insignificant between the two groups. The r* of healthy rats was significantly larger than the elastase group (0.42 ± 0.03 vs. 0.28 ± 0.06), whereas ADC* was significantly smaller in healthy animals (0.27 ± 0.04 vs. 0.36 ± 0.01 cm 2 /s). No systematic difference in these quantities was observed between the three lung slices. A significant 33% increase in ADC* and a significant 31% decline in r* for elastase rats was observed compared with a significant 51% increase in C dyn and a nonsignificant 26% decline in FEV 50 /FRC. Correlation of imaging and PFT metrics revealed that r and ADC divide the rats into two separate clusters in the sample space.
Type of Medium:
Online Resource
ISSN:
8750-7587
,
1522-1601
DOI:
10.1152/japplphysiol.00269.2010
Language:
English
Publisher:
American Physiological Society
Publication Date:
2011
detail.hit.zdb_id:
1404365-8
SSG:
12
SSG:
31
Bookmarklink