PET-measured longitudinal flow gradient correlates with invasive fractional flow reserve in CAD patients

Ines Valenta, Alexander Antoniou, Wael Marashdeh, Thorsten Leucker, Edward Kasper, Steven R. Jones, Robert F. Dannals, Lilja Solnes, Martin G. Pomper, Thomas H. Schindler

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Aims: We aimed to evaluate whether a PET-determined longitudinal decrease in myocardial blood flow (MBF) or gradient, assumed as a more specific flow parameter for epicardial resistance, correlates with invasively measured fractional flow reserve (FFR) in coronary artery disease (CAD) patients. Methods and Results: In 29 patients with suspected or known CAD, myocardial perfusion and MBF in mL/g/min was determined with 13N-ammonia PET/CT during regadenoson stimulation and at rest, and corresponding myocardial flow reserve (MFR = MBF stress/MBF rest) was calculated. MBF parameters were assessed in the myocardial region with stress-related perfusion defect and with stenosis ≥50% (Region 1), without defect but with stenosis ≥50% (Region 2), or without stenosis ≥50% (Region 3). Hyperaemic MBFs were significantly lower in the mid-distal than in the mid-left ventricular myocardium in Regions 1-3 [median and IQ range: 1.57 (1.24, 1.84) vs. 1.87 (1.61, 2.00), and 1.23 (1.11, 1.86) vs. 1.89 (1.80, 1.97), and 1.78 (1.48, 2.00) vs. 1.94 (1.84, 2.05) mL/g/min, P < 0.0001]. Resulting longitudinal MBF gradient during hyperaemic flows was more pronounced in Region 2 than in Regions 1 and 3, respectively [-0.46 (-0.70, -0.10) vs. -0.17 (-0.29, -0.11) and -0.15 (-0.25, -0.09) mL/g/min, respectively, P < 0.01]. There was a significant correlation between the hyperaemic longitudinal MBF gradient and FFR (r = 0.95; P < 0.0001), while this association was less pronounced for corresponding MFR (r = 0.50; P = 0.006). Conclusion: The observed close correlation between a longitudinal MBF gradient during hyperaemic flows and invasively measured FFR suggests the longitudinal flow gradient as an emerging non-invasive index of flow-limiting CAD.

Original languageEnglish
Pages (from-to)538-548
Number of pages11
JournalEuropean heart journal cardiovascular Imaging
Issue number5
StatePublished - May 1 2017


  • CAD
  • PET
  • circulation
  • coronary stenosis
  • flow gradient
  • microvascular function
  • myocardial blood flow
  • myocardial flow reserve
  • myocardial perfusion


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