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emission attenuation correction
Journal of Nuclear Cardiology V o l u m e 4, Number 1, Part 2
Abstracts Monday morning, April 7, 1997
11.2
S 17
11.4
EFFECTS ON DIAGNOSTIC ACCURACY OF MYOCARDIAL SPECT OF TRANSMISSION/EMISSION ATTENUATION CORRECTION. M.DONDI; P.L.GUIDALO'I3"I; R. CASANOVA; A.L. PATRONCINI; S.FANTI; P.F.CAPACCI; A. MARESTA. Nuclear Me~cine Service and Division of Cardiology; Ospedale per gli Infermi, Faenza (RA), Italy This study aimed at evaluating if transmission/emission attenuation correction may increase dagnostic capabilities of SPECT. We used a threeheaded camera and a simultaneous transmission/emission aoopisition to produce a double series of tomographio studies, attenuation corrected (AC) and non-attenuation corrected (NAC) for each patient. We applied a segmental analysis (29 segments) and a qualitative 5-point score (0=norrflal; 4=no uptake). Overall 60 patients (48 males; 12 females) were submitted to coronary angiography and are the subjects of the present study. Significant CAD (stenosis >_70%)was found in 51 pts. LAD was involved in 27 cases, RCA in 24 and CX in 30. Singta-~,~sseldisease (1VD) was detected in 28 pts, two-vessel disease {2VD) in 16 and ~hree-vessel(3VD) in 7. Out of the 9 pls with all patent vessels, CAD was correctly ruled out in 8/9 (spac 89%) by AC-studtes and in 5/9 (spat 56%) by NAC-studias. AC-studies identified 1VD in 24/28 cases (86%); 2VD in 9116(56%) and 3VD in 6/7 (86%). NAC-studies identified lVD in 15/28 (54%); 2VD in 8/16 (50%) and 3VD in 2/7 (29%) of cases. Stenotic arteries were identified as follows: SENS
AC-atudiea SPEC
SENS
NAC-studies SPEC
IMPACT OF TRANSMISSION-EMISSION ATTENUATION CORRECTION ON MYOCARDIAL SPECT SPECIFICITY IN A POPULATION AT LOW-RISK FOR CAD. S.Fanti, M.Dondi, P.L.Guidalotti, S.Zoboli, A.Romeo, C.Corbelli, N.Monetti. Nuclear Medicine Dpt, S.Orscia-Malpighi Hospital, Bologna, Italia. Photonattenuationin the chestdeterminesalJfactualabnormalitiesof relativeb'acer dis~u6on in myoca-dialSPECT(M-SPECT),and attenua~onis retainedto be one of the majorcauseof falsepositivecetdiecperfusionimaging.In order to assessthe impactof attenuationcorrectionon M-SPECTspecificity,we evaluatedthe studiesof 67 consecutivepatientsat low prd~bility for CAD (< 5%). out of the population referredfor sb'eea+restM-SPECT.We employeda three-headcameraequipped~th a commercially available nnsmieaioNemission device. A double series of tor~ic studies,attonuationcorrected(AC) and non attenua~oncorrected(NC), were reconsltuetedand analysedadopting a qealitatJve5-point score (0=normal; 4=no uptake), For each myocardialwall a total score and a mean sege~ental score was calculated, We consideredas false positiveall studieswib 2 or more segments
scored;P_2.Resultsare detailedin tab.1.After attenuationcorrectionsegmentsof the TABLE1 TOTAL SCORE infadorand septet walls stressNC .restNC ;stressAC restAC showed a significant ANTER 28 22 40 35 decreaseof their scores APEX
INFER SEPT LATER
.... 69
15t 130 51
53 139
77 82
75 64
(p<0.05), while segmentsof the anterior
126
63
58
wall showed a mild
38
42
31
increase o[
score,
CX 87% (26/30) 96% (27/28) 73% (22/30) 96% (27/28) In ~g~.lusions, attenuation correction increased diagnostic a~curacy of SPECT, improving bofh sensitivity and specificity. This approach seems to be a definite improvement of myocardial SPECT.
though the change did not reach sta~slk~alsignificance(p=ns). The applicationof aflenuationeoweclion. decreasedthe false positiverate from 25.4% (17/67)to 4.4% (3/87) for 14Cand AC studies raspec~ely. In conclusion,nonuniformattenuationwithin ~ chest heavily affected M-SPECT results in a pq0~lation at low risk for CAD. Correction for aUeouationarfifects effectivelyreducedthe numberof false positivestudies,~th a consequentimprovementof specificity.
11.3
11.5
i~EFT MAIN CORONARY DISEASE: INCREASED SENSITIVITY WITH QUANTITATIVE ATTENUATION CORRECTED SPECT PERFUSION IMAGING C. D u v e r n o y , E. Ficaro, M. K a r a b a j a k i a n , P. Rose, J. Corbett. U n i v e r s i t y of M i c h i g a n , A n n Arbor, MI, U.S.A.
LVEF CALCULATED FROM GATED THALLIUM (G TI) SPECT: COMPARISON WITIt Te-99m MUGASTUDIES, H.M, Abdet-Davem, M. N. Infantino', D.S. Acun~, S. Atay, J.Q, Luo, E.L Bemaski', H.H. AbujudehT,H. Etmquist'.S.Y. Naddaf, W.S. Omar, M. Kumar. Nucl Mad Sec,Dept Rad & Card See', Dept Med. St Vincent'sHosp & Mud Center of NY and NY Mud Coll, ValhallaN,Y.
T h e s e n s i t i v i t y o f S P E C T p e r f u s i o n i m a g i n g is g e n e r a l l y e x c e l l e n t for the d e t e c t i o n o f c o r o n a r y h e a r t disease. H o w e v e r , p r e s u m a b l y b e c a u s e of b a l a n c e d reductions in m y o c a r d i a l p e r f u s i o n , S P E C T has d e m o n s t r a t e d l i m i t e d s e n s i t i v i t y for the i d e n t i f i c a t i o n o f a pattern s p e c i f i c for left m a i n ( L M ) c o r o n a r y stenosis. B e c a u s e r e g i o n a l q u a n t i t a t i v e p e r f u s i o n b i a s e s are e l i m i n a t e d w i t h a t t e n u a t i o n c o r r e c t e d (AC) vs. u n c o r r e c t e d (UC) S P E C T , w e h y p o t h e s i z e d that A C SPECT should demonstrate increased diagnostic sensitivity for the d e t e c t i o n o f s i g n i f i c a n t L M c o r o n a r y s t e n o s e s . W e s t u d i e d 2 0 pts. (17 m e n , 13 p r i o r M I ) a g e 66+9 yrs w i t h s i g n i f i c a n t L M s t e n o s e s ( > 5 0 % stenosis). S i g n i f i c a n t coronary stenoses w e r e also p r e s e n t in 19 L A D , 13 L C x , and 17 R C A territories. S t r e s s T c - 9 9 m s e s t a m i b i S P E C T a n d A C w e r e p e r f o r m e d as w e h a v e p r e v i o u s l y described. Both A C and U C i m a g e s w e r e q u a n t i f i e d and c o m p a r e d to the a p p r o p r i a t e A C and U C n o r m a l d a t a b a s e s (_>2.5SD, 3-D M S P E C T ) . U C S P E C T i d e n t i f i e d 34 a n d A C 51 of the s t e n o s e d territories (p<0.001). T h e r e w e r e i n c r e a s e s in defect e x t e n t scores in the A C i m a g e s for all c o r o n a r y territories. A l a r g e c o n t i g u o u s area of r e d u c e d p e r f u s i o n e n c o m p a s s i n g > 2 0 % o f both the L A D and L C x t e r r i t o r i e s w a s c o n s i d e r e d s p e c i f i c for L M stenosis. W i t h A C S P E C T 14/20 pts. (70%) d e m o n s t r a t e d the L M pattern o f a b n o r m a l i t y w h e r e a s only 3 pts. (15%) did so with UC SPECT (p=0.001). Conclusion: Attenuation corrected S P E C T results in s i g n i f i c a n t l y i n c r e a s e d s e n s i t i v i t y for left m a i n c o r o n a r y stenoses.
Recent advances in multidetectorgamma cameras, acquisition and processing protocols have made multlgatedTI SPECT myocardialperfusfun (MP) imaging available and feasible for clinical practice. The purpose of this study was to correlate LVEF calculated(talc) t~'omG TI SPECT in both the early (E) and the delayed(D) imagingwith that talc from Tc-99m MUGA studies. 41 patients(29 M and 12 F) who were referred for stress TI MP imaging (treadmill (I 9) or pharmaco[stressing(17 adenosine. 5 dobutamine),age 39 to 89 years with mean age 61.7 years. All pts had IV injection 2.8-3.2 mCi of TI-201 at peak exerciseand imaged 15 rain and 3 hours later, dual head (ADAC, Vertex Epic at 90"), 16 projectionsper head for a total of 32 projections, 180",64 x 64 matrix, 60 secondsper projectionand 8 slicesper cardiaccycle. E and D summedimageswere processedand displayedfor evaluationof MP. Gatedstudieswere processedfor cale of LVEF accordingto manufacturers'protocol. All pts agreed for Te-99m MUGA study immediately following TI study using Tc-99m pertachnetate for invlvo labelledRBCs technique20 mCi, IV, MUGAstudies were processed for eatc of LVEF. 24 pts had history of at least 3 risk factors ~rbr1HD with abnormalMP studies, 21 had normalMP, 18 stressiuducedmyocardialischemiaaud 2 had myocardialscar. The calc LVEF ranged from 17-81% with a mean of 54.59% from the E gated SPECTand rangedfrom 21-81% with a mean of 54.88% from the D gated SPECT studies,From mugaLVEFrangedfrom 19-77%with a meanof 53,75%. Correlation ofcalc LVEFbetweenthe MUGA and the E gated SPECT was 0.8 with SD 13 and betweenthe MUGAand the delayedG SPECTwas 0.9 with SD 14.
LAD
92% (25/27)
97% (32/33)
67% (18/27)
100%(3,3/33)
RCA
87% (21/24)
92% (35/38)
91% (22/24)
53% (20/38)
We conclude:G TI SPECT is useful for LVEF ealc and correlateswith MUGA. This further promotesTI use for MP imaging.With currenttechnology,low dose and energyof Tl is not a limitationfor the G SPECT,
Abstracts Monday morning, April 7, 1997
11.2
S 17
11.4
EFFECTS ON DIAGNOSTIC ACCURACY OF MYOCARDIAL SPECT OF TRANSMISSION/EMISSION ATTENUATION CORRECTION. M.DONDI; P.L.GUIDALO'I3"I; R. CASANOVA; A.L. PATRONCINI; S.FANTI; P.F.CAPACCI; A. MARESTA. Nuclear Me~cine Service and Division of Cardiology; Ospedale per gli Infermi, Faenza (RA), Italy This study aimed at evaluating if transmission/emission attenuation correction may increase dagnostic capabilities of SPECT. We used a threeheaded camera and a simultaneous transmission/emission aoopisition to produce a double series of tomographio studies, attenuation corrected (AC) and non-attenuation corrected (NAC) for each patient. We applied a segmental analysis (29 segments) and a qualitative 5-point score (0=norrflal; 4=no uptake). Overall 60 patients (48 males; 12 females) were submitted to coronary angiography and are the subjects of the present study. Significant CAD (stenosis >_70%)was found in 51 pts. LAD was involved in 27 cases, RCA in 24 and CX in 30. Singta-~,~sseldisease (1VD) was detected in 28 pts, two-vessel disease {2VD) in 16 and ~hree-vessel(3VD) in 7. Out of the 9 pls with all patent vessels, CAD was correctly ruled out in 8/9 (spac 89%) by AC-studtes and in 5/9 (spat 56%) by NAC-studias. AC-studies identified 1VD in 24/28 cases (86%); 2VD in 9116(56%) and 3VD in 6/7 (86%). NAC-studies identified lVD in 15/28 (54%); 2VD in 8/16 (50%) and 3VD in 2/7 (29%) of cases. Stenotic arteries were identified as follows: SENS
AC-atudiea SPEC
SENS
NAC-studies SPEC
IMPACT OF TRANSMISSION-EMISSION ATTENUATION CORRECTION ON MYOCARDIAL SPECT SPECIFICITY IN A POPULATION AT LOW-RISK FOR CAD. S.Fanti, M.Dondi, P.L.Guidalotti, S.Zoboli, A.Romeo, C.Corbelli, N.Monetti. Nuclear Medicine Dpt, S.Orscia-Malpighi Hospital, Bologna, Italia. Photonattenuationin the chestdeterminesalJfactualabnormalitiesof relativeb'acer dis~u6on in myoca-dialSPECT(M-SPECT),and attenua~onis retainedto be one of the majorcauseof falsepositivecetdiecperfusionimaging.In order to assessthe impactof attenuationcorrectionon M-SPECTspecificity,we evaluatedthe studiesof 67 consecutivepatientsat low prd~bility for CAD (< 5%). out of the population referredfor sb'eea+restM-SPECT.We employeda three-headcameraequipped~th a commercially available nnsmieaioNemission device. A double series of tor~ic studies,attonuationcorrected(AC) and non attenua~oncorrected(NC), were reconsltuetedand analysedadopting a qealitatJve5-point score (0=normal; 4=no uptake), For each myocardialwall a total score and a mean sege~ental score was calculated, We consideredas false positiveall studieswib 2 or more segments
scored;P_2.Resultsare detailedin tab.1.After attenuationcorrectionsegmentsof the TABLE1 TOTAL SCORE infadorand septet walls stressNC .restNC ;stressAC restAC showed a significant ANTER 28 22 40 35 decreaseof their scores APEX
INFER SEPT LATER
.... 69
15t 130 51
53 139
77 82
75 64
(p<0.05), while segmentsof the anterior
126
63
58
wall showed a mild
38
42
31
increase o[
score,
CX 87% (26/30) 96% (27/28) 73% (22/30) 96% (27/28) In ~g~.lusions, attenuation correction increased diagnostic a~curacy of SPECT, improving bofh sensitivity and specificity. This approach seems to be a definite improvement of myocardial SPECT.
though the change did not reach sta~slk~alsignificance(p=ns). The applicationof aflenuationeoweclion. decreasedthe false positiverate from 25.4% (17/67)to 4.4% (3/87) for 14Cand AC studies raspec~ely. In conclusion,nonuniformattenuationwithin ~ chest heavily affected M-SPECT results in a pq0~lation at low risk for CAD. Correction for aUeouationarfifects effectivelyreducedthe numberof false positivestudies,~th a consequentimprovementof specificity.
11.3
11.5
i~EFT MAIN CORONARY DISEASE: INCREASED SENSITIVITY WITH QUANTITATIVE ATTENUATION CORRECTED SPECT PERFUSION IMAGING C. D u v e r n o y , E. Ficaro, M. K a r a b a j a k i a n , P. Rose, J. Corbett. U n i v e r s i t y of M i c h i g a n , A n n Arbor, MI, U.S.A.
LVEF CALCULATED FROM GATED THALLIUM (G TI) SPECT: COMPARISON WITIt Te-99m MUGASTUDIES, H.M, Abdet-Davem, M. N. Infantino', D.S. Acun~, S. Atay, J.Q, Luo, E.L Bemaski', H.H. AbujudehT,H. Etmquist'.S.Y. Naddaf, W.S. Omar, M. Kumar. Nucl Mad Sec,Dept Rad & Card See', Dept Med. St Vincent'sHosp & Mud Center of NY and NY Mud Coll, ValhallaN,Y.
T h e s e n s i t i v i t y o f S P E C T p e r f u s i o n i m a g i n g is g e n e r a l l y e x c e l l e n t for the d e t e c t i o n o f c o r o n a r y h e a r t disease. H o w e v e r , p r e s u m a b l y b e c a u s e of b a l a n c e d reductions in m y o c a r d i a l p e r f u s i o n , S P E C T has d e m o n s t r a t e d l i m i t e d s e n s i t i v i t y for the i d e n t i f i c a t i o n o f a pattern s p e c i f i c for left m a i n ( L M ) c o r o n a r y stenosis. B e c a u s e r e g i o n a l q u a n t i t a t i v e p e r f u s i o n b i a s e s are e l i m i n a t e d w i t h a t t e n u a t i o n c o r r e c t e d (AC) vs. u n c o r r e c t e d (UC) S P E C T , w e h y p o t h e s i z e d that A C SPECT should demonstrate increased diagnostic sensitivity for the d e t e c t i o n o f s i g n i f i c a n t L M c o r o n a r y s t e n o s e s . W e s t u d i e d 2 0 pts. (17 m e n , 13 p r i o r M I ) a g e 66+9 yrs w i t h s i g n i f i c a n t L M s t e n o s e s ( > 5 0 % stenosis). S i g n i f i c a n t coronary stenoses w e r e also p r e s e n t in 19 L A D , 13 L C x , and 17 R C A territories. S t r e s s T c - 9 9 m s e s t a m i b i S P E C T a n d A C w e r e p e r f o r m e d as w e h a v e p r e v i o u s l y described. Both A C and U C i m a g e s w e r e q u a n t i f i e d and c o m p a r e d to the a p p r o p r i a t e A C and U C n o r m a l d a t a b a s e s (_>2.5SD, 3-D M S P E C T ) . U C S P E C T i d e n t i f i e d 34 a n d A C 51 of the s t e n o s e d territories (p<0.001). T h e r e w e r e i n c r e a s e s in defect e x t e n t scores in the A C i m a g e s for all c o r o n a r y territories. A l a r g e c o n t i g u o u s area of r e d u c e d p e r f u s i o n e n c o m p a s s i n g > 2 0 % o f both the L A D and L C x t e r r i t o r i e s w a s c o n s i d e r e d s p e c i f i c for L M stenosis. W i t h A C S P E C T 14/20 pts. (70%) d e m o n s t r a t e d the L M pattern o f a b n o r m a l i t y w h e r e a s only 3 pts. (15%) did so with UC SPECT (p=0.001). Conclusion: Attenuation corrected S P E C T results in s i g n i f i c a n t l y i n c r e a s e d s e n s i t i v i t y for left m a i n c o r o n a r y stenoses.
Recent advances in multidetectorgamma cameras, acquisition and processing protocols have made multlgatedTI SPECT myocardialperfusfun (MP) imaging available and feasible for clinical practice. The purpose of this study was to correlate LVEF calculated(talc) t~'omG TI SPECT in both the early (E) and the delayed(D) imagingwith that talc from Tc-99m MUGA studies. 41 patients(29 M and 12 F) who were referred for stress TI MP imaging (treadmill (I 9) or pharmaco[stressing(17 adenosine. 5 dobutamine),age 39 to 89 years with mean age 61.7 years. All pts had IV injection 2.8-3.2 mCi of TI-201 at peak exerciseand imaged 15 rain and 3 hours later, dual head (ADAC, Vertex Epic at 90"), 16 projectionsper head for a total of 32 projections, 180",64 x 64 matrix, 60 secondsper projectionand 8 slicesper cardiaccycle. E and D summedimageswere processedand displayedfor evaluationof MP. Gatedstudieswere processedfor cale of LVEF accordingto manufacturers'protocol. All pts agreed for Te-99m MUGA study immediately following TI study using Tc-99m pertachnetate for invlvo labelledRBCs technique20 mCi, IV, MUGAstudies were processed for eatc of LVEF. 24 pts had history of at least 3 risk factors ~rbr1HD with abnormalMP studies, 21 had normalMP, 18 stressiuducedmyocardialischemiaaud 2 had myocardialscar. The calc LVEF ranged from 17-81% with a mean of 54.59% from the E gated SPECTand rangedfrom 21-81% with a mean of 54.88% from the D gated SPECT studies,From mugaLVEFrangedfrom 19-77%with a meanof 53,75%. Correlation ofcalc LVEFbetweenthe MUGA and the E gated SPECT was 0.8 with SD 13 and betweenthe MUGAand the delayedG SPECTwas 0.9 with SD 14.
LAD
92% (25/27)
97% (32/33)
67% (18/27)
100%(3,3/33)
RCA
87% (21/24)
92% (35/38)
91% (22/24)
53% (20/38)
We conclude:G TI SPECT is useful for LVEF ealc and correlateswith MUGA. This further promotesTI use for MP imaging.With currenttechnology,low dose and energyof Tl is not a limitationfor the G SPECT,