title: Inflow-weighted pulmonary perfusion: comparison between dynamic contrast-enhanced MRI versus perfusion scintigraphy in complex pulmonary circulation.
abstract: BACKGROUND
  Due to the different properties of the contrast agents, the lung perfusion maps as measured by 99mTc-labeled macroaggregated albumin perfusion scintigraphy (PS) are not uncommonly discrepant from those measured by dynamic contrast-enhanced MRI (DCE-MRI) using indicator-dilution analysis in complex pulmonary circulation. Since PS offers the pre-capillary perfusion of the first-pass transit, we hypothesized that an inflow-weighted perfusion model of DCE-MRI could simulate the result by PS.
  
  
  METHODS
  22 patients underwent DCE-MRI at 1.5T and also PS. Relative perfusion contributed by the left lung was calculated by PS (PS(L%)), by DCE-MRI using conventional indicator dilution theory for pulmonary blood volume (PBV(L%)) and pulmonary blood flow (PBFL%) and using our proposed inflow-weighted pulmonary blood volume (PBV(iw)(L%)). For PBViw(L%), the optimal upper bound of the inflow-weighted integration range was determined by correlation coefficient analysis.
  
  
  RESULTS
  The time-to-peak of the normal lung parenchyma was the optimal upper bound in the inflow-weighted perfusion model. Using PSL% as a reference, PBV(L%) showed error of 49.24% to -40.37% (intraclass correlation coefficient R(I) = 0.55) and PBF(L%) had error of 34.87% to -27.76% (R(I) = 0.80). With the inflow-weighted model, PBV(iw)(L%) had much less error of 12.28% to -11.20% (R(I) = 0.98) from PS(L%).
  
  
  CONCLUSIONS
  The inflow-weighted DCE-MRI provides relative perfusion maps similar to that by PS. The discrepancy between conventional indicator-dilution and inflow-weighted analysis represents a mixed-flow component in which pathological flow such as shunting or collaterals might have participated.
authors: Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan.
authors: Yi-Ru
authors: YR
authors: Lin
authors: Shang-Yueh
authors: SY
authors: Tsai
authors: Teng-Yi
authors: TY
authors: Huang
authors: Hsiao-Wen
authors: HW
authors: Chung
authors: Yi-Luan
authors: YL
authors: Huang
authors: Fu-Zong
authors: FZ
authors: Wu
authors: Chu-Chuan
authors: CC
authors: Lin
authors: Nan-Jing
authors: NJ
authors: Peng
authors: Ming-Ting
authors: MT
authors: Wu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001810:Blood Volume; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D003097:Collateral Circulation; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007201:Indicator Dilution Techniques; D007223:Infant; D008168:Lung / Q000098:blood supply*; D008171:Lung Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D055420:Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011652:Pulmonary Circulation; D019275:Radiopharmaceuticals; D012039:Regional Blood Flow; D013997:Time Factors
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019786:Gadolinium DTPA