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Polarmaps of myocardial blood flow from dynamic [O-15]water pet-studies
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M O N D A Y A M A P R I L 7
Abstracts Monday morning, April 7, 1997
Journal of Nuclear Cardiology January/February 1997, Part 2
8.38
8.40
POLARMAPS OF MYOCARDIAL BLOOD FLOW FROM DYNAMIC [O-15]WATER PET-STUDIES. F. Hermansen, P.G, Camici and A.A. Lammertsma, Cyclotron Unit, MRC Clinical Sciences Centre, Hammersmith Hospital, London, UK.
CONSTANCY OF MYOCARDIAL BLOOD FLOW AND PAIN PERCEPTION OVER TIME IN PATIENTS W1TH SYNDROME X SD Rosen, H Boyd, *J-C Kaski and PG Camiei. MRC-CSC/RPMS, Hammersmith Hospital and *St George's tlospilal, London, UK.
The purpose of the present study was to develop a method with substantially improved precision for calculation of myocardial blood flow (MBF) with [O-15]water and PET. Methods Two linear combinations (representing essentially flow and tissue volume) of the dynamic sinograms were reconstructed iteratively providing two low-noise images. MBF polarmaps were generated as the quotient in 109 ROIs of these images and corrected for non-linearity. The results of the present method were compared with those of traditional non-linear regression in both normal and hyperemic states of three patients with coronary artery disease (CAD). Results The noise was 2.5 + 0.4 times lower (P<0.0001) with the new method. MBF values were similar although not identical with the two methods. The hyperemic polarmaps showed the expected flow patterns for the CAD patients. Conclusions The new method reduces substantially the noise in MBF measurements. Further studies are needed for validation.
8.39 CORONARY FLOW RESERVE DETERMINATION AFTER HEART TRANSPLANTATION M. M. Kbrner, D. Bailer, N. Kromer, G. Gleichmann, G. Notohamiprodjo, R. Koerfer Heart Center NRW, Ruhr University of Bochum, 32545 Bad Oeynhausen, Germany To measure the coronary flow reserve (CFR) in 14 heart transplant recipients (HTx) (group A) calculation of myocardial blood flow (MBF) was performed by the N-13 ammonia PET (Siemens ECAT-951]R) following i.v. application of I015 mCi N-13 ammonia at rest and after pharmacological determination of coronary vasodilation reserve. CFR was calculated as MBF-dipyridamole/basal MBF ratio. Reference: 7 patients (group B) with normal CFR and coronary angiograms and 23 patients (group C) with angina pectoris withoutlwith minor angiographic coronary disease. Results (mean values ± standard deviation): Mean CFR was significantly reduced in HTx with 1.6 • 3 compared to group C: 2.5 ± 0.7 and compared to B: 4.7 ± 0.8. The dipyridamoleinduced mean coronary flow was: 200 ± 71 in HTx compared to 199 ± 45/ml]min I00 g in C and 396 ± 59 in B.
In HTx the determination of CRF by PET contribute to objectifying or excluding a limited blood flow regulation.
We previously investigated patients with syndrome X [SX, angina, isehaemie-like changes in the stress electrocardiogram (ECG) and a :normal coronary arteriogram] and found no relationships amongst m y ~ d i a l blood flow (MBF), ECG changes and pain perception after dipyridamole challenge (D). To assess the stability of these parameters, we repeated the investigationS, (identical technique), in 14 SX, 9 female, age [mean (SD)] 52 (8) years. MBF (ml/min/g) was measuredat rest (R) and after intravenous D (0.56 mg/kg over 4 rain) using positron emission tomography (PET) with H2150 -: Chest pain 'was noted as P+ , its severity scoredon a 0--10 scale (pain score). The reinvestigation (Study II) took place 212 (251) days after the original study (Study 1) and ,after 10 days' placebo therapy. MBF(R) did not differ between the studies: 1.16 (0.41) in study I vs 1.20 (0.26) in Study IL Resting MBF was cbrrected for heart rate (HR) x systolic blood pressure (SBP) as: MBF(Corr) = MBF(Rest)xl04/(HRxSBP). MBF(Corr) was unchanged; 1.34 (0.35) in Study I vs 1.43 (0.37) in Study II, p=NS. MBF(D)was also comparable: 3.11 (L08) in study I vs 3.65 (1.13) in study II. Corrected coronary vasodilator reserve [MBF(D)/MBFCorr)] was unchanged: 2.38 (0.75) vs 2.64 (0.85), p=NS. Pain score tended to be lower in Study II: 4.2 (3.2) vs 3.0 (3.0), p=O.07. In Study I as in Study If, no relationships were fotmd amongst MBF, ECG changes and P+. In conclusion, MBF values me in the normal range in SX patients [Normals: (n=20, age 51(15) years, p=NS vs patients) MBF(R) 1.00 (0.22), MBF(D) 3.00 (1.00), MBF(Corr) 1.34 (0.29), CVR 3.06 (1.08), CVR(Corr) 2.34 (0.90)]; MBF and CVR remain stable over time. The placebo may influence pereeivedchest pain in SX.
8.41 DIRECT COMPARISON OF N-13 PET AND SESTAMIBISPECT PERFUSION IMAGING IN SEVERE CHF PATIENTS.
M.Bottcher, N.P.Sand, M.M.Madsen, T.T.Nietsen, M.Rehling. Dept. of Card. and dept. ofNucl. Med., Aarhus Univ. Hosp., Denmark PET-scanning enables detection of myocardial viability. Due to the limited availability of PET facilities it has been proposed to combine Sestamibi-SPECT with FDG-PET. A prerequisite for this is that PET and SPECT yields similar perfusion scans. Thirty-one patients (57+8 years, mean EF 27+8%) with verified CAD were included. In random order perfusion scans using Ammonia-PET and Sestamibi-SPECT were performed. Two blinded observers scored a total of 610 segments on a 5-point scale in a 20 segment model of the left ventricle. Segmental score-differences (SPECT-PET) in % of the total number of segments are show~: . 0 -1,0rl >2 < -2 No, Segm K Anterior# 43 71 19 10 90 ' Lateral# 60 86 4 10 185 iI Ai}i_e.ai# 38 82 13 5 61 [ 0.53# I Septal + 42 68 28 4 185 I 0.33+ Posterior+ 25 63 32 5 89 ! 0.42 Overall 45 75 18 7 610 # and + represent weighted kappa (•) for pooled data of regional groups. The repeatability for SPECT and PET, (-l,0,1)-values, were 94% and 92%, respectively. In conclusion PET mid SPECT perfusion scans yield similar results, except for the septal and posterior regions, where SPECT tends to overestimate perfusion defects, most likely due to attenuation artifacts. Hence attenuation correction should be considered when combining FDG-PET and Sestamibi-SPECT for diagnosing myocardial viability.
M O N D A Y A M A P R I L 7
Abstracts Monday morning, April 7, 1997
Journal of Nuclear Cardiology January/February 1997, Part 2
8.38
8.40
POLARMAPS OF MYOCARDIAL BLOOD FLOW FROM DYNAMIC [O-15]WATER PET-STUDIES. F. Hermansen, P.G, Camici and A.A. Lammertsma, Cyclotron Unit, MRC Clinical Sciences Centre, Hammersmith Hospital, London, UK.
CONSTANCY OF MYOCARDIAL BLOOD FLOW AND PAIN PERCEPTION OVER TIME IN PATIENTS W1TH SYNDROME X SD Rosen, H Boyd, *J-C Kaski and PG Camiei. MRC-CSC/RPMS, Hammersmith Hospital and *St George's tlospilal, London, UK.
The purpose of the present study was to develop a method with substantially improved precision for calculation of myocardial blood flow (MBF) with [O-15]water and PET. Methods Two linear combinations (representing essentially flow and tissue volume) of the dynamic sinograms were reconstructed iteratively providing two low-noise images. MBF polarmaps were generated as the quotient in 109 ROIs of these images and corrected for non-linearity. The results of the present method were compared with those of traditional non-linear regression in both normal and hyperemic states of three patients with coronary artery disease (CAD). Results The noise was 2.5 + 0.4 times lower (P<0.0001) with the new method. MBF values were similar although not identical with the two methods. The hyperemic polarmaps showed the expected flow patterns for the CAD patients. Conclusions The new method reduces substantially the noise in MBF measurements. Further studies are needed for validation.
8.39 CORONARY FLOW RESERVE DETERMINATION AFTER HEART TRANSPLANTATION M. M. Kbrner, D. Bailer, N. Kromer, G. Gleichmann, G. Notohamiprodjo, R. Koerfer Heart Center NRW, Ruhr University of Bochum, 32545 Bad Oeynhausen, Germany To measure the coronary flow reserve (CFR) in 14 heart transplant recipients (HTx) (group A) calculation of myocardial blood flow (MBF) was performed by the N-13 ammonia PET (Siemens ECAT-951]R) following i.v. application of I015 mCi N-13 ammonia at rest and after pharmacological determination of coronary vasodilation reserve. CFR was calculated as MBF-dipyridamole/basal MBF ratio. Reference: 7 patients (group B) with normal CFR and coronary angiograms and 23 patients (group C) with angina pectoris withoutlwith minor angiographic coronary disease. Results (mean values ± standard deviation): Mean CFR was significantly reduced in HTx with 1.6 • 3 compared to group C: 2.5 ± 0.7 and compared to B: 4.7 ± 0.8. The dipyridamoleinduced mean coronary flow was: 200 ± 71 in HTx compared to 199 ± 45/ml]min I00 g in C and 396 ± 59 in B.
In HTx the determination of CRF by PET contribute to objectifying or excluding a limited blood flow regulation.
We previously investigated patients with syndrome X [SX, angina, isehaemie-like changes in the stress electrocardiogram (ECG) and a :normal coronary arteriogram] and found no relationships amongst m y ~ d i a l blood flow (MBF), ECG changes and pain perception after dipyridamole challenge (D). To assess the stability of these parameters, we repeated the investigationS, (identical technique), in 14 SX, 9 female, age [mean (SD)] 52 (8) years. MBF (ml/min/g) was measuredat rest (R) and after intravenous D (0.56 mg/kg over 4 rain) using positron emission tomography (PET) with H2150 -: Chest pain 'was noted as P+ , its severity scoredon a 0--10 scale (pain score). The reinvestigation (Study II) took place 212 (251) days after the original study (Study 1) and ,after 10 days' placebo therapy. MBF(R) did not differ between the studies: 1.16 (0.41) in study I vs 1.20 (0.26) in Study IL Resting MBF was cbrrected for heart rate (HR) x systolic blood pressure (SBP) as: MBF(Corr) = MBF(Rest)xl04/(HRxSBP). MBF(Corr) was unchanged; 1.34 (0.35) in Study I vs 1.43 (0.37) in Study II, p=NS. MBF(D)was also comparable: 3.11 (L08) in study I vs 3.65 (1.13) in study II. Corrected coronary vasodilator reserve [MBF(D)/MBFCorr)] was unchanged: 2.38 (0.75) vs 2.64 (0.85), p=NS. Pain score tended to be lower in Study II: 4.2 (3.2) vs 3.0 (3.0), p=O.07. In Study I as in Study If, no relationships were fotmd amongst MBF, ECG changes and P+. In conclusion, MBF values me in the normal range in SX patients [Normals: (n=20, age 51(15) years, p=NS vs patients) MBF(R) 1.00 (0.22), MBF(D) 3.00 (1.00), MBF(Corr) 1.34 (0.29), CVR 3.06 (1.08), CVR(Corr) 2.34 (0.90)]; MBF and CVR remain stable over time. The placebo may influence pereeivedchest pain in SX.
8.41 DIRECT COMPARISON OF N-13 PET AND SESTAMIBISPECT PERFUSION IMAGING IN SEVERE CHF PATIENTS.
M.Bottcher, N.P.Sand, M.M.Madsen, T.T.Nietsen, M.Rehling. Dept. of Card. and dept. ofNucl. Med., Aarhus Univ. Hosp., Denmark PET-scanning enables detection of myocardial viability. Due to the limited availability of PET facilities it has been proposed to combine Sestamibi-SPECT with FDG-PET. A prerequisite for this is that PET and SPECT yields similar perfusion scans. Thirty-one patients (57+8 years, mean EF 27+8%) with verified CAD were included. In random order perfusion scans using Ammonia-PET and Sestamibi-SPECT were performed. Two blinded observers scored a total of 610 segments on a 5-point scale in a 20 segment model of the left ventricle. Segmental score-differences (SPECT-PET) in % of the total number of segments are show~: . 0 -1,0rl >2 < -2 No, Segm K Anterior# 43 71 19 10 90 ' Lateral# 60 86 4 10 185 iI Ai}i_e.ai# 38 82 13 5 61 [ 0.53# I Septal + 42 68 28 4 185 I 0.33+ Posterior+ 25 63 32 5 89 ! 0.42 Overall 45 75 18 7 610 # and + represent weighted kappa (•) for pooled data of regional groups. The repeatability for SPECT and PET, (-l,0,1)-values, were 94% and 92%, respectively. In conclusion PET mid SPECT perfusion scans yield similar results, except for the septal and posterior regions, where SPECT tends to overestimate perfusion defects, most likely due to attenuation artifacts. Hence attenuation correction should be considered when combining FDG-PET and Sestamibi-SPECT for diagnosing myocardial viability.