title: Feasibility and Diagnostic Potential of Pulmonary Transit Time Measurement by Contrast Echocardiography: A Pilot Study.
abstract: OBJECTIVE
  Pulmonary transit time (PTT; the time for ultrasound contrast to travel from the right ventricle [RV] to the left atrium) may provide a single metric that reports on cardiopulmonary function while overcoming some of the challenges of standard echocardiographic measures. We conducted a pilot study to test the feasibility and reproducibility of echocardiographically derived PTT and to determine its association with established measures of cardiopulmonary function.
  
  
  RESULTS
  A total of 39 patients receiving clinically indicated ultrasound contrast were prospectively enrolled. PTT was measured in the apical four-chamber view using commercially available software. Reproducibility and inter-observer agreement were assessed in 9 patients. PTT was correlated with established measures of left ventricular systolic and diastolic function, RV function, and pulmonary vascular status. PTT could be measured in 89% (33/37) of patients without a contraindication to ultrasound contrast; all measurements from the last 20 patients were interpretable and obtained independently by a sonographer. Reproducibility and inter-observer agreement were excellent. PTT correlated well with standard echocardiographic indicators of cardiac status. A PTT >4.5 seconds accurately identified all but 1 patient with cardiopulmonary dysfunction.
  
  
  CONCLUSIONS
  This pilot study demonstrates that measurement of PTT using ultrasound contrast is highly reproducible, accurately reflects global cardiopulmonary function across a range of cardiopulmonary disease, and can be readily obtained by an independent sonographer. Further studies are needed to determine whether PTT has incremental value in diagnosis and prognosis compared to conventional echocardiographic parameters.
authors: Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.
authors: Evan L
authors: EL
authors: Brittain
authors: Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.
authors: Laura N
authors: LN
authors: Doss
authors: Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.
authors: Linda
authors: L
authors: Saliba
authors: Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.
authors: Waleed
authors: W
authors: Irani
authors: Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.
authors: Benjamin F
authors: BF
authors: Byrd
authors: Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.
authors: Ken
authors: K
authors: Monahan
mesh_terms: D002318:Cardiovascular Diseases / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000493:pharmacokinetics*; D004452:Echocardiography / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006334:Heart Function Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D011652:Pulmonary Circulation / Q000502:physiology*; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media
keywords: contrast echocardiography; diastolic dysfunction; heart failure; left ventricular function; right ventricular function