INTRODUCTION: Mild ischemia

in the inferolateral wall on myocardial perfusion

imaging is seen frequently in practice. The aim

of this study is to assess the importance of the

above issue on myocardial perfusion SPECT

with coronary angiography.

PATIENTS AND METHODS: All patients enrolled

in this study exhibited mild ischemia of

the inferolateral wall on myocardial single photon

emission computed tomography (SPECT)

with 99mTc-MIBI, using the 20 left ventricular

segments model. Each patient completed a

questionnaire, including type of chest pain, risk

factors, and previous examinations, and all cases

were followed up for one year. Luminal stenosis

of >50% was classified as significant stenosis

on coronary angiography. A p value < 0.05

was considered statistically significant.

RESULTS: During investigation, 105 cases had

mild ischemia on myocardial perfusion imaging

(MPI) of which 36 subjects (22 male and 14 female)

underwent coronary angiography. The

mean age was 56.62±10.23 years old (age range:

36-73 years). The inferolateral wall was compared

to the left circumflex (LCX) territory. Nineteen

out of 36 (52.7%) cases had stenosis in the

LCX. Twenty-three of 105 (21.90%) underwent

revascularization during the one year follow up.

In multiple logistic regressions, with LCX stenosis

on angiography as the dependent variable,

only abnormal MPI was independently associated

significantly.

CONCLUSIONS: The findings of the study may

indicate that even a mild perfusion defect in the

inferolateral wall should be carefully managed,

especially in high-risk subjects for coronary

artery disease.

European Review for Medical and Pharmacological Sciences

Clinical significance of mild inferolateral wall

ischemia of the left ventricle on 99mTc-MIBI

myocardial perfusion single photon emission

computed tomography (SPECT)

M. ASSADI, A. ABDI-ARDEKANI1, M. POURBEHI2, A. AMINI2,

H. JAVADI3, I. NABIPOUR, M. ABBASZADEH3, M. ASSADI3

The Persian Gulf Tropical Medicine Research Center, Bushehr University of Medical Sciences,

Bushehr, Iran

1Department of Cardiology, Bushehr Heart Center, Faculty of Medicine, Bushehr University of

Medical Sciences, Bushehr, Iran

2Golestan Research Center of Gastroenterology and Hepatology (GRCGH), Golestan University of

Medical Sciences (GUOMS), Gorgan, Iran

3The Persian Gulf Nuclear Medicine Research Center, Bushehr University of Medical Sciences

ABBASZADEH, M

ABDI-ARDEKANI, A

AMINI, A

ASSADI, M

JAVADI3, H

NABIPOUR, I

POURBEHI, M

INTRODUCTION: Mild ischemia

in the inferolateral wall on myocardial perfusion

imaging is seen frequently in practice. The aim

of this study is to assess the importance of the

above issue on myocardial perfusion SPECT

with coronary angiography.

PATIENTS AND METHODS: All patients enrolled

in this study exhibited mild ischemia of

the inferolateral wall on myocardial single photon

emission computed tomography (SPECT)

with 99mTc-MIBI, using the 20 left ventricular

segments model. Each patient completed a

questionnaire, including type of chest pain, risk

factors, and previous examinations, and all cases

were followed up for one year. Luminal stenosis

of >50% was classified as significant stenosis

on coronary angiography. A p value < 0.05

was considered statistically significant.

RESULTS: During investigation, 105 cases had

mild ischemia on myocardial perfusion imaging

(MPI) of which 36 subjects (22 male and 14 female)

underwent coronary angiography. The

mean age was 56.62±10.23 years old (age range:

36-73 years). The inferolateral wall was compared

to the left circumflex (LCX) territory. Nineteen

out of 36 (52.7%) cases had stenosis in the

LCX. Twenty-three of 105 (21.90%) underwent

revascularization during the one year follow up.

In multiple logistic regressions, with LCX stenosis

on angiography as the dependent variable,

only abnormal MPI was independently associated

significantly.

CONCLUSIONS: The findings of the study may

indicate that even a mild perfusion defect in the

inferolateral wall should be carefully managed,

especially in high-risk subjects for coronary

artery disease.

Key Words:

Myocardial perfusion imaging (MPI), Inferolateral

wall, SPECT

Pourbehi, Mohammad Reza

JAVADI, H

Nabipour, Iraj

Bushehr University of Medical Sciences Repository

Abstract. – INTRODUCTION: Mild ischemiain the inferolateral wall on myocardial perfusionimaging is seen frequently in practice. The aimof this study is to assess the importance of theabove issue on myocardial perfusion SPECTwith coronary angiography.PATIENTS AND METHODS: All patients en-rolled in this study exhibited mild ischemia ofthe inferolateral wall on myocardial single pho-ton emission computed tomography (SPECT)with 99mTc-MIBI, using the 20 left ventricularsegments model. Each patient completed aquestionnaire, including type of chest pain, riskfactors, and previous examinations, and all cas-es were followed up for one year. Luminal steno-sis of >50% was classified as significant steno-sis on coronary angiography. A p value < 0.05was considered statistically significant.RESULTS: During investigation, 105 cases hadmild ischemia on myocardial perfusion imaging(MPI) of which 36 subjects (22 male and 14 fe-male) underwent coronary angiography. Themean age was 56.62±10.23 years old (age range:36-73 years). The inferolateral wall was com-pared to the left circumflex (LCX) territory. Nine-teen out of 36 (52.7%) cases had stenosis in theLCX. Twenty-three of 105 (21.90%) underwentrevascularization during the one year follow up.In multiple logistic regressions, with LCX steno-sis on angiography as the dependent variable,only abnormal MPI was independently associat-ed significantly.CONCLUSIONS: The findings of the study mayindicate that even a mild perfusion defect in theinferolateral wall should be carefully managed,especially in high-risk subjects for coronaryartery disease.European Review for Medical and Pharmacological SciencesClinical significance of mild inferolateral wallischemia of the left ventricle on 99mTc-MIBImyocardial perfusion single photon emissioncomputed tomography (SPECT)M. ASSADI, A. ABDI-ARDEKANI1, M. POURBEHI2, A. AMINI2,H. JAVADI3, I. NABIPOUR, M. ABBASZADEH3, M. ASSADI3The Persian Gulf Tropical Medicine Research Center, Bushehr University of Medical Sciences,Bushehr, Iran1Department of Cardiology, Bushehr Heart Center, Faculty of Medicine, Bushehr University ofMedical Sciences, Bushehr, Iran2Golestan Research Center of Gastroenterology and Hepatology (GRCGH), Golestan University ofMedical Sciences (GUOMS), Gorgan, Iran3The Persian Gulf Nuclear Medicine Research Center, Bushehr University of Medical Sciences,Bushehr, IranCorresponding Author: Majid Assadi, MD; e-mail: assadipoya@yahoo.com, asadi@bpums.ac.ir 2639Key Words:Myocardial perfusion imaging (MPI), Inferolateralwall, SPECT.IntroductionCardiovascular disease is the main cause ofdeath in humans and it is characterized by signif-icant societal morbidity and huge health carecost1,2. Myocardial perfusion imaging (MPI) is anextremely important procedure in the accuratemanagement of patients with cardiovascular dis-ease because it provides unique information fordiagnosing cardiovascular disease, making prog-noses, evaluating therapies , and assessing viabil-ity3,4. Nonetheless, it also exposes a number ofpotential artifacts that can limit its use4,5. Arti-facts and pitfalls may be related to the equip-ment, the patient, or the technologist4,5. Further-more, mild ischemia in the inferolateral wall onmyocardial perfusion imaging is seen frequentlyin practice. This can be due to real perfusion de-fects, artifacts, or some anomalies6,7.This study was designed to determine the clin-ical significance of mild inferolateral wall is-chemia on MPI in patients suspected of having orknown to have coronary artery disease (CAD),with coronary angiography serving as the refer-ence standard. Also, the study included a one-year follow up.2013; 17: 2639-26432640Patients and MethodsParticipants and Study DesignOne hundred and thirty patients with known orsuspected CAD, who were referred to the Re-searchers’ Center for myocardial perfusion imag-ing from January 2007 to September 2009, wereinvited to participate in the study. Inclusion in theinvestigation was restricted to patients who hadmild ischemia of the inferolateral wall on themyocardial perfusion single photon emissioncomputed tomography (SPECT) with 99mTc-MIBI, using the 20 left ventricular segmentsmodel. None of the participants had valvularheart disease (VHD), congestive heart failure(CHF), congenital heart disease (CHD), or car-diomyopathy. Patients who were not eager totake part in the study or did not meet the requi-site eligibility for the study were excluded. Theremaining 105 subjects who gave informed con-sent were enrolled in the study.Body weight, height, and blood pressure weredetermined during the initial investigation. Riskfactors encountered during the study included:(1) hypertension (self-reported history of hyper-tension and/or use of antihypertensive medica-tion, or a blood pressure > 140/90 mm Hg); (2)smoking; (3) dyslipidemia (high-density lipopro-tein cholesterol < 40 mg/dl, low-density lipopro-tein cholesterol > 100 mg/dl, or antihypercholes-terolemic treatment); and (4) family history ofcoronary heart disease (in men, a first-degree rel-ative < 55 years of age; in women, a first-degreerelative < 65 years of age). The pretest likelihoodof CAD was anticipated by consideration of age,the ratio of cholesterol to HDL, gender, andsmoking8.All cases were followed for one year.The study complies with the Declaration ofHelsinki and it was confirmed by the institutionalEthics Committee of Bushehr University of Med-ical Sciences.Study ProtocolAll subjects underwent a 2 day SPECT proto-col. Technetium-99m sestamibi was intravenous-ly injected at rest and during exercise or pharma-cologic stress.Dipyridamole Technetium 99m-SestamibiSPECT ProtocolAll cardiovascular drugs were stopped for atleast 2 days and participants fasted overnight be-fore the study. An intravenous line of normalsaline solution was inserted into an antecubitalvein using a 20-gauge cannula. Dipyridamole(0.56 mg/kg) was administered over 4 min A12-lead ECG was recorded and patient symptomswere continuously monitored and noted. A doseof 740 MBq of Tc-99m sestamibi as a compactbolus was administered 4 min after the beginningof the infusion. Twenty minutes later, the patientswere requested to eat a fatty meal to hasten hepa-tobiliary clearance of Tc-99m sestamibi, andimaging occurred 90 minutes after the initial in-fusion of dipyridamole. The rest phase took placethe next day.Exercise Stress ProtocolAll cardiovascular drugs were stopped for atleast 2 days and participants fasted overnight be-fore the study. All cases were asked to exerciseon a treadmill under a standard Bruce protocol.740 MBq (20 mCi) Tc-99m MIBI as a compactbolus was administered when the peak heart ratewas achieved (more than 85% of the age-predict-ed maximum heart rate), at the appearance oftypical angina, and/or at positive exercise ECGfindings. The exercise test was recorded to con-firm if there was a horizontal or down-sloping STsegment depression more than 1 mm for 80 mi-croseconds after the J point. Imaging was per-formed 15-30 minutes after exercise. On the nextday, 20 minutes after the administration of 740MBq Tc-99m MIBI, the patients were requestedto eat a fatty meal to accelerate hepatobiliaryclearance of Tc-99m MIBI. The resting SPECTwas carried out 90 minutes after Tc-99m MIBIadministration.Acquisition and Processing ProtocolsA double-head SPECT scintillation camera(ADAC Genesys, Malpitas CA, USA) was uti-lized to obtain 32 views over 180º using a step-and-shoot method, progressing from 45º right an-terior oblique to 45º left posterior oblique projec-tions. A symmetric 20% energy window over the140 keV Tc-99m photopeak and a low energyall-purpose (LEAP) collimator were used, andthe data were stored in 64 * 64 matrices. Acquisi-tion time was 25 seconds per projection duringrest and stress studies. An expert nuclear medi-cine specialist used the cine display of the rotat-ing planar projections to evaluate sub-diaphrag-matic activities, attenuations, and patient motionto optimize the quality of the images. Processingwas performed using a two-dimensional Butter-worth prefilter and a ramp filter for back projec-M. Assadi, A. Abdi-Ardekani, M. Pourbehi, A. Amini, H. Javadi, I. Nabipour, M. Abbaszadeh, M. AssadiMild inferolateral ischemia2641Coronary ArteriographyThirty-six of the 105 patients underwent coro-nary angiography to confirm myocardial is-chemia. Coronary arteriography was done with amonoplane imaging system and recorded onDVD. Angiographic images were visually as-sessed by two readers who were blind to the MPIdata. Luminal stenosis of > 50% was consideredsignificant stenosis.Statistical AnalysisA 2-tailed t-test compared the mean values be-tween groups. Continuous variables are ex-pressed as the mean ± SD, and categorical vari-ables as the absolute values and percentages. Thechi-square test was used for categorical variables.Multiple logistic regression analysis was used toascertain the association of angiographic resultsas dependent variables and the remaining itemswere considered covariates. The statistical analy-sis was done using the Statistical Package for theSocial Science (SPSS) version 18, (SPSS Inc.,Chicago, IL, U.S.A). A p value < 0.05 was con-sidered statistically significant.ResultsDuring the investigation of 105 cases with mildischemia on MPI, 36 subjects (22 males and 14 fe-males) underwent coronary angiography. The meantion of transaxial tomographic images. Thetransaxial images were reoriented along the verti-cal long axis, the horizontal axis, and the shortaxis of the left ventricle. Acquisition parameterswere similar for the rest and stress studies. Foreach patient, each of the three stress images wasinterpreted individually in comparison to thesame rest image.Visual SPECT AnalysisFor assessment, scans were divided into 20segments, corresponding to the location of theterritories of the various coronary arteries (Figure1). For evaluation of the segments, a five-gradescale was used: normal perfusion, mild, moder-ate, and severe ischemia, and fixed segments. Is-chemia was defined as the existence of a regionwith decreased or absent myocardial activity onexercise scans but that improved on the rest stageimages. A fixed segment was defined as a regionof decreased or absent myocardial activity bothon exercise and rest sets. The location of eachsegment was corresponded to each vessel territo-ry based on the 20-segment model of MPI size.In this way, the inferolateral wall was congruentwith the LCX territory (Figure 1).Image interpretation was performed visually,supported by standard autoquant software (Auto-QUANT; ADAC Laboratories, Milpitas, CA,USA), by two observers without knowledge ofthe patient’s data.Figure 1. The 20-segment model, obtained by three individual short-axis slices as well as one mid-cavity vertical long-axisslice. A depiction of the coronary artery distribution is also noted. (LAD: left anterior descending coronary artery; LCX: leftcircumflex coronary artery; RCA: right coronary artery).2642age was 56.62±10.23 years old (age range: 36-73years). In 25 (69.4%) patients, stress was created bydipyridamole and in 11 (30.6%) cases by treadmillexercise. In total, 16 (44.4%) cases had hyperten-sion, 18 (50%) had hyperlipidemia, 9 (25%) had di-abetes mellitus, 2 (5%) were obese, 20 (55.55%)smoked, and 7 (19.44%) cases had a family historyof CAD. In addition, 7 (19.44%) cases had typicalchest pain and the remaining 29 (80.56%) cases hadatypical chest pain.In total, 25 cases had stenosis in at least onevessel on angiography. Nineteen out of 36(52.7%) cases had stenosis in LCX.According to the pretest likelihood of CAD as-sessment, 13 (36.11%) cases had low risk ofCAD (Group1), 17 (47.22%) had intermediaterisk of CAD (Group 2) and 6 (16.66%) had highrisk of CAD (Group 3). Seven out of 13 cases inGroup 1, 9 out of 17 cases in Group 2, and 3 outof 6 cases in Group 3 had obvious stenosis in theLCX artery on angiography.In multiple logistic regressions with angio-graphic results as dependent variables, only theMPI results were independently associated sig-nificantly (p value < 0.05). None of the othervariables – family history of CAD, age, obesity,ejection fraction (EF), electrocardiographic(ECG) results, type of chest pain, and pretestlikelihood of CAD – showed such a correlation(p value > 0.05).In addition, 23 of the 105 cases (21.90%) un-derwent revascularization during the one-yearfollow up.DiscussionThe main finding of this study was the goodcorrelation of detection of CAD between MPIand angiography in the LCX territory. More than1/2 of the patients with mild inferolateral is-chemia, as evaluated by MPI SPECT, had a sig-nificant stenosis in the LCX artery. In addition,when patients with more severe ischemia (i.e.moderate, severe, and fixed perfusion defects)were included, this correlation was higher thanthe current value.Inferolateral wall ischemia, mainly mild inseverity, am seen frequently in practice and thecurrent study was designed to ascertain the im-portance of this finding. The inferolateral wallperfusion defect is also observed in some anom-alies6,7,9. MPI in the patients with an anomalousleft coronary artery arising from the pulmonaryartery [Bland-Garland White syndrome (BGWS)]depicted a perfusion defect in the posterolateralwall6,9. In anomalous origins of the entire coro-nary system by three separate ostia within theright coronary sinus, a perfusion defect in the in-ferolateral region was seen6,7. Because possibleanomalies can create perfusion defect images,Researchers checked all cases for anomalies dur-ing angiography and found.Artifacts related to the patients, equipment, ortechnologist may establish the same defect; thesemay be ruled out by careful attention during eachstage of MPI implementation, before the inter-pretation of each image4.In the literature, a number of investigations as-sess the accuracy of MPI in determining CAD inLCX territory3,10. In our previous study, sensitivi-ty and specificity of MPI in LCX territory were80% and 81%, respectively11. In that study, weenrolled all perfusion defects, regardless of de-grees of severity.Bae et al10 compared tc-99m-MIBI myocardialSPECT results with the findings of coronary an-giographies in 98 male and 37 female patientswho underwent dipyridamole Tc-99m-MIBI my-ocardial imaging within one month of cardiaccatheterization. They showed that sensitivity inmen and women was 52.2% and 46.7%, respec-tively, for LCX (p = ns); the specificity was88.9% and 86.4%, respectively, for LCX (p=ns)10. They concluded that Tc-99m-MIBI my-ocardial SPECT was a safe, noninvasive test forthe evaluation of CAD and that there was no gen-der difference in detecting CAD.The current investigation demonstrated that al-though the possibility of CAD is higher in pa-tients with more risk factors, only MPI perfusiondefects had good correlations with documentedangiographic CADs. It also showed that MPI isan accurate method to depict significant coronarystenosis in LCX territory in patients suspected ofhaving or known to have CAD.Finally, it depicted that even mild inferolateralperfusion defects in patients should be carefullymanaged because more than 1/5 cases underwentrevascularization during the one-year follow up;however these data must be vigilantly interpretedbecause of the small sample size in this study.In addition to the small sample size, this re-search had several limitations. Assessments ofglobal and regional ventricular function with gat-ed MPS were not carried out in this study, as gat-ed MPS assessments were not routinely done atthe center. Angiography was limited to abnormalM. Assadi, A. Abdi-Ardekani, M. Pourbehi, A. Amini, H. Javadi, I. Nabipour, M. Abbaszadeh, M. AssadiMPI cases, for ethical reasons. However, theprobability of abnormal angiography in subjectswith normal MPI is low and Researchers fol-lowed the patients for one year. Finally, a longerfollow-up study to evaluate the progression ofmyocardial abnormalities did not occur.ConclusionsThe findings of the study may indicate thateven a mild perfusion defect in the inferolateralwall should be carefully managed, especially inhigh-risk subjects for coronary artery disease.–––––––––––––––––––AcknowledgementsThis study was the thesis of Dr. Mahsan Assadi and was car-ried out with the support of Bushehr University of MedicalSciences (grant no. 765). Thanks are extended to Colleaguesat our Institutes for technical help and data acquisition.––––––––––––––––––––Conflict of InterestThe Authors declare that they have no conflict of interests.References1) JAVADI H, PORPIRANFAR MA, SEMNANI S, JALLALAT S,YAVARI P, MOGHARRABI M, HOOMAN A, AMINI A,BAREKAT M, IRANPOUR D, SEYEDABADI M, ASSADI M, ASLIIN. Scintigraphic parameters with emphasis onperfusion appraisal in rest 99mTc-sestamibiSPECT in the recovery of myocardial function af-ter thrombolytic therapy in patients with ST eleva-tion myocardial infarction (STEMI). Perfusion2011; 26: 394-399.2) ROSENSTOCK L, OLSEN J. Firefighting and death fromcardiovascular causes. N Engl J Med 2007; 356:1261-1263.3) MOHAGHEGHIE A, AHMADABADI MN, HEDAYAT DK,POURBEHI MR, ASSADI M. Myocardial perfusionimaging using technetium-99m sestamibi inasymptomatic diabetic patients. Nuklearmedizin2011; 50: 3-8.4) BURRELL S, MACDONALD A. Artifacts and pitfalls inmyocardial perfusion imaging. J Nucl Med Tech-nol 2006; 34: 193-211.5) GERMANO G. Technical aspects of myocardialSPECT imaging. J Nucl Med 2001; 42: 1499-1507.6) MOODIE DS, COOK SA, GILL CC, NAPOLI CA. Thalli-um-20 1 myocardial imaging in young adults withanomalous left coronary artery arising from thepulmonary artery. J Nucl Med 1980; 21: 1076-1079.7) AL-MOHAISSEN M, HEILBRON B, LEIPSIC J, IGNASZEWSKIA. Anomalous origin of the entire coronary sys-tem by three separate ostia within the right coro-nary sinus--a rarely observed coronary anomaly.Can J Cardiol 2010; 26: 206-2008.8) 1996 NATIONAL HEART FOUNDATION CLINICAL GUIDE-LINES FOR THE ASSESSMENT AND MANAGEMENT OF DYSLIPI-DAEMIA. Dyslipidaemia Advisory Group on behalfof the Scientific Committee of the National HeartFoundation of New Zealand. N Z Med J 1996;109: 224-231.9) KATSURAGI M, YAMAMOTO K, TASHIRO T, NISHIHARA H,TOUDOU K. Thallium-201 myocardial SPECT inBland-White-Garland syndrome: two adult pa-tients with inferoposterior perfusion defect. J NuclMed 1993; 34: 2182-2184.10) BAE SK, LEE DS, OH BH, CHUNG JK, LEE MM, PARKYB, LEE MC, SEO JD, LEE YW, KOH CS. Comparisonof diagnostic accuracy for detecting coronaryartery disease of dipyridamole Tc-MIBI myocar-dial SPECT and it’s defect map between men andwomen. Korean J Nucl Med 1993; 27: 59-64.11) FARD-ESFAHANI A, ASSADI M, SAGHARI M, MOHAGHEGHIEA, FALLAHI B, EFTEKHARI M, BEIKI D, TAKAVAR A,NABIPOUR I, EBRAHIMI A, IZADYAR S, ANSARI-GILANI K.The role of myocardial perfusion imaging in theevaluation of patients undergoing percutaneoustransluminal coronary angioplasty. Hellenic J Car-diol 2009; 50: 396-401.2643Mild inferolateral ischemia

Clinical significance of mild inferolateral wall

ischemia of the left ventricle on 99mTc-MIBI

myocardial perfusion single photon emission

computed tomography (SPECT)

http://eprints.bpums.ac.ir/6590/1/2639-2643.pdf

Clinical significance of mild inferolateral wall ischemia of the left ventricle on 99mTc-MIBI myocardial perfusion single photon emission computed tomography (SPECT)

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