Comparison between the summed difference score and myocardial blood flow measured by13N-ammonia.
Both the myocardial perfusion pattern and myocardial blood flow (MBF) are used to assess patients with suspected coronary artery disease (CAD). The aim of this study was to compare the perfusion pattern (using the summed difference score [SDS]) to MBF in a consecutive group of patients undergoing PET/CT with 13 N-ammonia (13NH3).



47 consecutive patients, aged 65 ± 12 years (42 men) with known or suspected CAD, underwent vasodilator stress/rest PET/CT with13NH3for clinical indications. The SDS was determined by a commercially available software based on a 17-segment model. MBF was measured at rest and during hyperemia by dynamic acquisition and single-compartment model analysis. From the rest and stress MBF, the absolute difference (stress-rest) in myocardial blood flow defined as difference in myocardial blood flow (DMBF) was derived.



There were no significant differences between patients with no ischemia (SDS ≤ 1) and those with ischemia (SDS > 1) in CFR (2.84 ± 0.73 vs 2.63 ± 0.89, P = NS) and DMBF (1.34 ± 0.45 vs 1.24 ± 0.53 mL·minute-1·g-1, P = NS). There were however significant regional differences (141 different vascular territories in 47 patients) between these two groups (CFR: 2.84 ± 0.95 vs 2.16 ± 0.57, P < .001 and DMBF: 1.39 ± 0.6 vs 0.87 ± 0.39, P < .0001). The correlation between regional CFR and regional DMBF with SDS was significant (y = 2.7145e-0.059xR = 0.358 and y = 1.2769e-0.119xR = 0.44) CONCLUSION: The SDS is the difference between two measurements (stress-rest) and it correlates better with regional DMBF, which is another measurement that reflects the difference between stress and rest. The correlation is better on regional than global basis.
Chair of Nuclear Medicine and Nuclear Medicine Unit, Department of Medical Imaging, University and Spedali Civili, Piazza Spedali Civili, 1, Brescia, Italy. giubbini@med.unibs.it.
Raffaele
R
Giubbini
Chair of Nuclear Medicine and Nuclear Medicine Unit, Department of Medical Imaging, University and Spedali Civili, Piazza Spedali Civili, 1, Brescia, Italy.
Alessia
A
Peli
Nuclear Medicine Unit, San Giacomo Apostolo Hospital, Castelfranco Veneto, TV, Italy.
Elisa
E
Milan
Nuclear Medicine Unit, Department of Experimental and Clinical Biomedical Science, University of Florence, Florence, Italy.
Roberto
R
Sciagrà
Chair of Nuclear Medicine and Nuclear Medicine Unit, Department of Medical Imaging, University and Spedali Civili, Piazza Spedali Civili, 1, Brescia, Italy.
Luca
L
Camoni
Chair of Nuclear Medicine and Nuclear Medicine Unit, Department of Medical Imaging, University and Spedali Civili, Piazza Spedali Civili, 1, Brescia, Italy.
Domenico
D
Albano
Chair of Nuclear Medicine and Nuclear Medicine Unit, Department of Medical Imaging, University and Spedali Civili, Piazza Spedali Civili, 1, Brescia, Italy.
Mattia
M
Bertoli
Chair of Nuclear Medicine and Nuclear Medicine Unit, Department of Medical Imaging, University and Spedali Civili, Piazza Spedali Civili, 1, Brescia, Italy.
Mattia
M
Bonacina
Chair of Nuclear Medicine and Nuclear Medicine Unit, Department of Medical Imaging, University and Spedali Civili, Piazza Spedali Civili, 1, Brescia, Italy.
Federica
F
Motta
Chair of Nuclear Medicine and Nuclear Medicine Unit, Department of Medical Imaging, University and Spedali Civili, Piazza Spedali Civili, 1, Brescia, Italy.
Massimo
M
Statuto
Health Physics Department, Spedali Civili, Brescia, Italy.
Carlo Alberto
CA
Rodella
Health Physics Department, Spedali Civili, Brescia, Italy.
Antonio
A
De Agostini
Nuclear Medicine Unit, Department of Experimental and Clinical Biomedical Science, University of Florence, Florence, Italy.
Raffaella
R
Calabretta
Chair of Nuclear Medicine and Nuclear Medicine Unit, Department of Medical Imaging, University and Spedali Civili, Piazza Spedali Civili, 1, Brescia, Italy.
Francesco
F
Bertagna
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000641:Ammonia; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003326:Coronary Circulation; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009590:Nitrogen Radioisotopes; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*
D009590:Nitrogen Radioisotopes; C000615247:Nitrogen-13; D000641:Ammonia
Coronary blood flow; Coronary flow reserve; Myocardial perfusion imaging: PET; N-13 ammonia