Pulmonary scintigraphy in elastase-induced emphysema in pigs. Correlation with high-resolution computed tomography and histology.
OBJECTIVE
The objective of this study is to evaluate the mild physiologic changes of elastase-induced pulmonary emphysema in the pig by radionuclide scintigraphy and to correlate these findings with high-resolution computed tomography (HRCT) and histologic examination.


METHODS
Eight 7- to 12-week-old Yorkshire pigs were studied. Perfusion and ventilation studies were performed in six pigs at 1- or 2-week intervals after elastase instillation. HRCT was simultaneously performed for correlation with radionuclide scintigraphy. For the perfusion scans, technetium 99m (99mTc) macroaggregated albumin (MAA) was used, and both planar and single-photon emission CT (SPECT) images were obtained. Ventilation studies were performed with xenon-133 gas with dynamic sequential imaging.


RESULTS
Histopathologic findings demonstrated dilatation and destruction of the alveoli and were similar to those previously reported by the authors. The SPECT perfusion images showed significantly impaired perfusion of the involved segment of the lung, corresponding to the region where elastase was instilled. The planar xenon-133 ventilation scintigraphy did not show abnormal air trapping. The mild emphysema induced with elastase manifested as decreased and impaired perfusion with no detectable ventilation abnormalities. The sensitivity of SPECT perfusion studies for the detection of the mild changes of elastase-induced pulmonary emphysema were higher than that of HRCT.


CONCLUSIONS
The perfusion studies reflect functional or physiologic changes in contrast to structural changes seen on HRCT. This pig model was valuable to study the scintigraphic manifestation of elastase-induced pulmonary emphysema.
Noma
S
S
Department of Radiology, Long Island Jewish Medical Center, Albert Einstein College of Medicine, New Hyde Park, New York 11042.
Moskowitz
G W
GW
Herman
P G
PG
Khan
A
A
Rojas
K A
KA
D000818:Animals; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D010196:Pancreatic Elastase; D011656:Pulmonary Emphysema / Q000139:chemically induced / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D013552:Swine; D013668:Technetium Tc 99m Aggregated Albumin; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014692:Ventilation-Perfusion Ratio; D014980:Xenon Radioisotopes
D013668:Technetium Tc 99m Aggregated Albumin; D014980:Xenon Radioisotopes; D010196:Pancreatic Elastase