133Xenon ventilation scintigraphy applied to bronchoscopic lung volume reduction techniques for emphysema: relevance of interlobar collaterals.
BACKGROUND
133Xenon ventilation scintigraphy and (99m)Tc-MAA perfusion scintigraphy can be used to assess dynamic ventilation patterns in patients with severe emphysema.


OBJECTIVE
To describe the scintigraphic features of attempted bronchoscopic lung volume reduction (BLVR), exploring mechanisms that might explain the unexpected lack of postoperative atelectasis.


METHODS
Five patients with heterogenous severe upper lobe emphysema were evaluated with 133Xenon ventilation and (99m)Tc-MAA perfusion scintigraphy, chest radiography, bronchoscopy and high resolution computed tomography before and up to 1 month after endoscopic placement of bronchial prostheses (BLVR). Ex vivo assessment of the lungs of two further patients with severe upper lobe emphysema was performed.


RESULTS
No significant subsegmental or lobar collapse was evident on post-procedure chest radiography or high resolution computed tomography, despite bronchoscopic confirmation of adequate position and functioning of prostheses. 133Xenon ventilation scintigraphy confirms significantly decreased upper lobe wash-in (P < 0.023), unchanged lower lobe wash-in and significantly increased lower lobe wash-out rates (P < 0.005) after BLVR. Significant redistribution of perfusion to the lower lobes occurred after BLVR (P < 0.025). Ex vivo experiments on explanted emphysematous lungs demonstrated that these findings could best be explained by collateral interlobar ventilation, which was calculated in one specimen to be as high as 15% of total lower lobe ventilation. Peri-valvular leak is a much less likely possibility.


CONCLUSIONS
133Xenon ventilation scintigraphy indicated the presence of significant interlobar collateral ventilation in patients with severe emphysema that may have major relevance to these novel alternative techniques to lung volume reduction surgery. 133Xenon scintigraphy can be used in the evaluation of severe emphysema before and after novel therapeutic interventions.
Salanitri
J
J
Department of Nuclear Medicine, Alfred Hospital and Monash University, Melbourne, Victoria, Australia.
Kalff
V
V
Kelly
M
M
Holsworth
L
L
Williams
T
T
Snell
G
G
D001999:Bronchoscopy; D003097:Collateral Circulation; D006801:Humans; D008875:Middle Aged; D011013:Pneumonectomy / Q000379:methods; D019736:Prostheses and Implants; D011656:Pulmonary Emphysema / Q000473:pathology / Q000601:surgery*; D014980:Xenon Radioisotopes
D014980:Xenon Radioisotopes