Pulmonary blood flow evaluation using a dynamic flat-panel detector: feasibility study with pulmonary diseases.
OBJECTIVE
Pulmonary ventilation and circulation dynamics are reflected on fluoroscopic images as changes in X-ray translucency. The purpose of this study was to investigate the feasibility of non-contrast functional imaging using a dynamic flat-panel detector (FPD).


METHODS
Dynamic chest radiographs of 20 subjects (abnormal, n = 12; normal, n = 8) were obtained using the FPD system. Image analysis was performed to get qualitative perfusion mapping image; first, focal pixel value was defined. Second, lung area was determined and pulmonary hilar areas were eliminated. Third, one cardiac cycle was determined in each of the cases. Finally, total changes in pixel values during one cardiac cycle were calculated and their distributions were visualized with mapping on the original image. They were compared with the findings of lung perfusion scintigraphy.


RESULTS
In all normal controls, the total changes in pixel value in one cardiac cycle decreased from the hilar region to the peripheral region of the lung with left-right symmetric distribution. In contrast, in many abnormal cases, pulmonary blood flow disorder was indicated as a reduction of changes in pixel values on a mapping image. The findings of mapping image coincided with those of lung perfusion scintigraphy.


CONCLUSIONS
Dynamic chest radiography using an FPD system with computer analysis is expected to be a new type of functional imaging, which provides pulmonary blood flow distribution additionally.
Tanaka
Rie
R
Division of Health Sciences, Department of Radiological Technology, Kanazawa University Graduate School of Medical Science, 5-11-80 Kodatsuno, Kanazawa, 920-0942, Japan. rie44@mhs.mp.kanazawa-u.ac.jp
Sanada
Shigeru
S
Fujimura
Masaki
M
Yasui
Masahide
M
Tsuji
Shiro
S
Hayashi
Norio
N
Nanbu
Yuko
Y
Matsui
Osamu
O
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008171:Lung Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging; D011237:Predictive Value of Tests; D011652:Pulmonary Circulation / Q000502:physiology*; D013902:Radiography, Thoracic / Q000295:instrumentation*; D055815:Young Adult