title: Quantitative analysis of regional lung ventilation and perfusion PET with (68)Ga-labelled tracers.
abstract: BACKGROUND
  The aims of this study were to determine the quantitative parameters of ventilation (V) and perfusion (Q) PET scans assessing V/Q quotients in patients with various lung pathologies, as well as the influence of patient position on regional perfusion patterns.
  
  
  METHODS
  Fifty-three patients (24 male and 29 female) underwent lung scintigraphy with (68)Ga-labelled radiopharmaceuticals. (68)Ga Galligas and B20 microspheres used for V and Q imaging were produced in-house. Images were acquired under a standard setup with two emission scans of the whole lung in the supine (S) position (acquisition time 3 min/bed position) on a PET/CT scanner combined with low-dose computed tomography (CT) for attenuation correction. In 27 patients the Q scan was repeated in the prone (P) position. Parametric images were calculated (V/Q, P/S when applicable) for each patient. Patients were grouped according to diagnostic findings, and V/Q ratio distributions were further analysed. Gradients of the regional blood flow in both the supine and prone position were calculated.
  
  
  RESULTS
  The results from visual interpretation could be confirmed with parametric images. Voxel-wise V/Q analysis revealed significant differences in descriptive parameters such as median, mean and SD between normal patients and patients with acute and previous pulmonary embolism. Skewness and kurtosis were not significantly different. The effect of gravitation could be demonstrated by significant position-dependent changes of the gradients in the ventral-dorsal and apical-basal directions.
  
  
  CONCLUSIONS
  PET/CT using (68)Ga-labelled tracers allows the application of quantitative procedures to improve functional pulmonary imaging in clinical diagnosis and research.
authors: aDepartment of Nuclear Medicine bDepartment of Radiology cPulmonary Engineering Group, Department of Anesthesiology and Intensive Care Medicine, Medical Faculty, University Hospital Carl Gustav Carus, TU Dresden, Dresden, Germany.
authors: Liane
authors: L
authors: Oehme
authors: Klaus
authors: K
authors: Zöphel
authors: Elena
authors: E
authors: Golgor
authors: Michael
authors: M
authors: Andreeff
authors: Gerd
authors: G
authors: Wunderlich
authors: Claudia
authors: C
authors: Brogsitter
authors: Marcelo G
authors: MG
authors: de Abreu
authors: Jörg
authors: J
authors: Kotzerke
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005710:Gallium Radioisotopes; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D016684:Prone Position; D011849:Radioactive Tracers; D012189:Retrospective Studies; D016683:Supine Position; D014692:Ventilation-Perfusion Ratio; D055815:Young Adult
chemical_list: D005710:Gallium Radioisotopes; D011849:Radioactive Tracers