Discordance between dipyridamole technetium-99m-sestamibi myocardial perfusion single photon emission computed tomography and two-dimensional echocardiography in Kawasaki disease--a preliminary report

This study attempts to establish a noninvasive diagnostic method for early assessment of cardiac involvement in Kawasaki disease (KD), 36 children with KD were studied. The presence of abnormal coronary arteries (CA) with aneurysms was determined by experienced pediatric cardiologists using two-dimensional echocardiography (2D-Echo). Rest and dipyridamole-stress technetium-99m sestamibi (Tc-MIBI) single photon emission computed tomography (SPECT) was performed on the 36 children with KD for the assessment of myocardial perfusion and for comparison with 2D-Echo findings. The results showed that (1) 17/36 (47.2%) of the cases had no aneurysm and 19/36 (52.8%) had significant aneurysms; (2) 16/36 (44.4%) of the cases had normal myocardial perfusion and 20/36 (55.6%) had myocardial perfusion defects; (3) 9/36 (25.0%) cases showed both normal 2D-Echo and Tc-MIBI SPECT findings and 12/36 (33.3%) showed both abnormal 2D-Echo and Tc-MIBI SPECT findings; and (4) There was poor agreement between 2D-Echo and Tc-MIBI SPECT findings (-value = 0.161, p = 0.332). We concluded that the most of the KD children had aneurysms or abnormal myocardial perfusion. However, poor agreement exists between 2D-Echo and Tc-MIBI SPECT findings with aneurysms and abnormal myocardial perfusion in patients with KD.     

Adenosine myocardial contrast echo in intermediate severity coronary stenoses: a prospective two-center study

Background We sought to evaluate the role of adenosine myocardial contrast echocardiography (MCE) for the determination of functional relevance of coronary stenoses with intermediate angiographic severity and compared the results to single photon imaging (SPECT). We hypothezised that sole assessment of myocardial blood volume changes during adenosine on MCE would indicate functional stensosis relevance when accompanied by increased myocardial oxygen consumption (MVO2). Methods Fifty-seven patients with ≥1 coronary stenosis underwent adenosine MCE (ultraharmonic imaging) and exercise SPECT. On MCE, myocardial blood volume was assessed and constant or increased myocardial opacification during adenosine coupled with increased MVO2 was defined as normal and decreased opacification as abnormal. Results Rate–pressure product significantly increased during adenosine in all patients due to reflex tachycardia following mild hypotension, indicative of increased MVO2. Concordance between MCE and SPECT for the detection of reversible myocardial perfusion defects was 89% (κ = 0.83). Comparison of regions between rest and during adenosine as opposed to comparison to remote regions of the same stage was important for accurate assessment because concordance betweenn MCE and SPECT was less on separate assessment at rest (73%, κ = 0.40) compared to stress (91%, κ = 0.81, P < 0.05) mainly due to territories scored normal on SPECT and abnormal on MCE. Conclusions Assessment of myocardial blood volume changes during adenosine using MCE can be used for the determination of the functional relevance of coronary stenoses of intermediate angiographic severity if MVO2 is increased during adenosine.     

Identification of hemodynamically significant coronary artery stenoses by dipyridamole-magnetic resonance imaging and99mTc-methoxyisobutyl-isonitrile-SPECT

Magnetic resonance imaging (MRI) has been used in conjunction with dipyridamole induced wall motion abnormalities for the noninvasive detection of coronary artery disease (CAD). To assess the clinical usefulness of dipyridamole-MRI for the localization of CAD and to evaluate the relation between dipyridamole induced wall motion abnormalities and myocardial perfusion 33 patients with severe CAD (>70% diameter reduction) underwent MRI at rest and after dipyridamole infusion (0.75 mg dipyridamole/kg over a period of 10 minutes). All patients performed exercise stress testing and 20 patients of the study group additionally had rest and exercise stress^99mTc-methoxyisobutyl-isonitrile-SPECT (MIBI-SPECT). Two patients (6%) could not be evaluated due to severe motion artifacts during dipyridamole MRI. Segmental wall motion and perfusion of corresponding short axis planes were related to the major coronary arteries using a standardized segmental coronary artery perfusion pattern. Detection of wall motion abnormalities or perfusion defects by 2 blinded observers in consensus was the criterion for grading a segment normal or pathologic. For localization of CAD, segmental gradings were related to the presumed coronary artery territories. Stress-ECG was pathologic in 19/31 patients yielding a sensitivity of 61% and dipyridamole induced angina was present in 68% (21/31) of patients. Dipyridamole-MRI detected coronary artery disease with a sensitivity of 84% (26/31 patients) and all patients with new wall motion abnormalities also had dipyridamole induced angina. For the subgroup of 20 patients with MIBI-SPECT images, CAD was detected by both MIBI-SPECT and Dipyridamole-MRI in 90% (18/20) of patients. Dipyridamole-MRI and MIBI-SPECT gradings agreed in 55/60 (92%) coronary artery perfusion territories. There were no significant differences with respect to the sensitivities of Dipyridamole-MRI/MIBI-SPECT for the localization of individual coronary artery stenoses yielding 81%/78% for left anterior descending, 80%/80% for left circumflex and 92%/89% for right coronary artery stenoses. However, specificity of Dipyridamole-MRI (89%) for the detection of RCA stenoses was slightly better than for MIBI-SPECT (80%). Dipyridamole-MRI induced regional wall motion abnormalities proved to be a highly sensitive parameter for the non-invasive localization of CAD. The similarity of dipyridamole-MRI and MIBI-SPECT results suggests a close agreement between functional and perfusion parameters in the assessment of hemodynamically significant coronary artery stenoses. The clinical utility of this MRI stress test is still limited by high cost and long imaging times which may, however, be overcome by the development of new shorter imaging sequences.     

Comparison of thallium-201 SPECT redistribution patterns and rubidium-82 PET rest-stress myocardial blood flow imaging

To compare regional thallium-201 SPECT redistribution patterns with rubidium-82 PET, we studied 81 patients with both imaging modalities. Sixty patients had significant coronary artery disease. All patients underwent PET imaging after dipyridamole infusion, while SPECT imaging was performed after exercise stress (38 patients) and dipyridamole (43 patients). Sixty-eight percent of patients with prior infarct had fixed defects on SPECT, compared to 39% with PET. Sixty-one percent of patients with prior infarct had PET perfusion defects which exhibited ‘reflow’ or normal rubidium-82 tracer uptake (p < 0.05 vs. SPECT). Similar results were seen in patients without prior infarct (26% fixed defects on SPECT vs. 12% for PET, p < 0.05). Regional analysis showed that 57% of fixed SPECT defects corresponded to PET defects with reflow or normal rubidium-82 uptake, while 78% of ‘fixed’ PET defects corresponded to fixed SPECT defects. PET reflow and normal rubidium-82 uptake in sites of fixed thallium-201 SPECT perfusion defects suggest that imaging modalities employing separate tracer injections at rest and after stress, such as rubidium-82 PET, may be more specific in the assessment of myocardial viability, especially in patients with prior myocardial infarction.     

A Reverse Perfusion Pattern During Technetium-99m Stress Myocardial Perfusion Imaging Does Not Predict Flow Limiting Coronary Artery Disease

BACKGROUND: A reverse redistribution pattern during myocardial perfusion imaging is most widely described using thallium (Tl-201), when stress images exhibit greater perfusion than rest. Technetium (Tc-99 m) radiopharmaceuticals may also yield a reverse perfusion (RP) pattern, but its significance is uncertain. This study tested the hypothesis that RP correlates with the presence and location of flow limiting coronary stenosis(es). METHOD: We reviewed 842 consecutive Tc-99 m tetrofosmin SPECT stress studies performed at a cardiothoracic centre over a 15 month period. 69 (8.2%) demonstrated RP. Thirty-three patients (age 32-79 mean 56, 17 female) had undergone cardiac catheterisation within 12 months of the scan. Correlation was sought between the presence and location of angiographic stenoses and RP pattern. RESULTS: 10/33 (30.3%) had significant (>60%) coronary stenosis(es); 5 single-vessel, 2 two-vessel and 3 three-vessel disease (3VD). Stenosis location correlated poorly with the RP territory (LAD/Anterior 5/17, RCA/Inferior 1/10, Cx/lateral 0/4 (p = 0.57)). Of the 6 patients with a lesion in the RP territory, 3 had 3VD; 2 of these had a simultaneous reversible defect. All 5 patients with previous myocardial infarction had a simultaneous fixed defect. However only 3/12 with co-existent reversible defects had significant disease. CONCLUSION: The reverse perfusion pattern is a poor predictor of flow limiting coronary disease, and does not correlate with stenosis location in those with significant lesions. Such patients should not undergo invasive investigation purely on the basis of this result.     

Arterial concentration of 99mTc-sestamibi at rest, during peak exercise and after dipyridamole infusion

Tracers for myocardial perfusion imaging during stress should not only have high cardiac uptake but they should also have a fast blood clearance to prevent myocardial tracer uptake after the ischaemic stimulus. The present study characterize the early phase of the arterial (99m)Tc-sestamibi (MIBI) time-activity curve after venous bolus injection at rest, during peak exercise and after dipyridamole infusion. We included 11 patients undergoing angioplasty for one-vessel disease (rest study) and 20 patients evaluated for the detection of haemodynamic significant coronary stenoses by (99m)Tc-sestamibi single photon emission computed tomography (SPECT) using either bicycle exercise testing (10 patients) or standard dipyridamole testing (10 patients). Arterial blood samples of 1 ml were taken from the left femoral artery (rest study) or the right radial artery (exercise and dipyridamole studies) every 5 s during the first 5 min postinjection. In the exercise and the dipyridamole studies blood sampling were extended to include blood samples every 5 min 5-30 min postinjection. Peak MIBI concentration was lower and decrease in concentration slower after tracer injection during exercise than during dipyridamole stress testing. This may cause an underestimation of perfusion defects during exercise because of MIBI uptake after the ischaemic stimulus. The implications of the study not only refer to the choice of stress modality when using MIBI. This study also underlines the importance of considering early blood clearance in addition to regional myocardial tracerkinetic aspects such as myocardial extraction fraction when new tracers are introduced.     

Feasibility of continuous venous infusion of SonoVue for qualitative assessment of reversible coronary perfusion defects in stress myocardial contrast echocardiography

OBJECTIVE: To study the feasibility of continuous intravenous SonoVue contrast echocardiography for qualitative assessment of reversible myocardial perfusion in dipyridamole stress tests. METHODS: Eleven patients (10 male and 1 female, mean age 66 years) with a history of chest pain and a clinical indication for stress sestamibi single photon emission computed tomography (SPECT) underwent concurrent SonoVue 99mTc myocardial contrast echocardiography (MCE). RESULTS: Of the total 176 segments obtained, 53 (30%) were regarded as indeterminate, 39 (22%) as discordant, and 84 (48%) as concordant between MCE and SPECT imaging. Two patients had abnormal SPECT results. The overall feasibility and specificity of MCE were 70 and 74%, respectively. The concordant (p = 0.59) and discordant (p = 0.55) segments were comparable with either MCE technique. However, continuous low-mechanical-index imaging produced fewer indeterminate segments (17 segments, 32%) than intermittent harmonic B-mode imaging (36 segments, 68%) (p = 0.04). Significantly more indeterminate segments were found in the left anterior descending artery territory. However, the overall concordance was similar (p = 0.5) in all three coronary artery territories. The concordance and discordance rates at different left ventricular levels (i.e., basal, mid, and apical) were similar (p = 0.50 and 0.08, respectively). CONCLUSION: Continuous-infusion SonoVue contrast echocardiography is feasible, with high specificity, for detecting myocardial perfusion defects as assessed by dipyridamole SPECT.     

Abnormal electron beam computed tomography results: the value of repeating myocardial perfusion single-photon emission computed tomography in the ongoing assessment of coronary artery disease

OBJECTIVE: To determine whether asymptomatic patients with atherosclerosis, indicated by the presence of coronary artery calcium on electron beam computed tomography, are at enough risk for progression of disease to justify a repeated stress single-photon emission computed tomography (SPECT) examination after an initial normal to low-risk perfusion study. PATIENTS AND METHODS: We retrospectively identified patients who had abnormal results on electron beam computed tomography (coronary artery calcium score > 0) and normal to low-risk results on SPECT (defined as a summed stress score of 0-3) within a 3-month period from January 1, 1995, to October 31, 2002. Of the 504 identified patients, 285 remained after exclusion criteria were applied. Of the 285 patients, 69 (mean +/- SD age, 58.2 +/- 7.6 years; 91% male) underwent at least 1 repeated myocardial perfusion SPECT imaging study within 4 years of their initial assessment as normal or at low risk without recurrence of symptoms. The value of repeated SPECT imaging was assessed by detection of a substantial change in the repeated SPECT study and by documentation of a clinical event (death, nonfatal myocardial infarction, or revascularization). Follow-up was 100% complete at a mean of 4.3 +/- 1.6 years. RESULTS: Only 4 patients (6%) had a substantial progression in their SPECT risk category; substantial changes on the SPECT scans occurred only in patients with a coronary artery calcium score greater than 100. Three patients underwent revascularization, yielding a 5-year rate for survival free of revascularization of 94% (95% confidence interval, 88%-100%). No deaths or nonfatal myocardial infarctions were reported. CONCLUSION: The principal findings of this study indicate that asymptomatic patients with initial normal or low-risk results from stress SPECT performed because of abnormal coronary artery calcium scores who remain asymptomatic are at low risk of death, myocardial infarction, or coronary revascularization. Three patients underwent revascularization by percutaneous coronary intervention despite the absence of symptoms. A substantial change in SPECT results (defined as progression from normal or low-risk summed stress score to intermediate- or high-risk summed stress score) affected 6% of patients and was not associated with any adverse hard events (nonfatal myocardial infarction or death).     

Effect of caffeine on myocardial perfusion imaging using single photon emission computed tomography during adenosine pharmacologic stress

Approximately 6 million cardiac stress tests are performed annually in the United States, of which 2.4 million are pharmacologic stress tests using agents such as adenosine. Adenosine induces differential coronary hyperemia in normal coronary arteries versus coronary arteries with atherosclerosis, allowing single photon emission computed tomography (SPECT) imaging to identify reduced coronary flow in segments subtended by diseased coronary arteries. The potential attenuation of pharmacologic effects of adenosine in the presence of caffeine is why patients are routinely instructed to abstain from caffeine for 12 to 24 hours prior to administration of an adenosine stress test. Failure to abstain from caffeine results in cancellation or delaying of cardiac stress testing, resulting in procedural delays and its impact on patient throughput. Recent studies have evaluated such interaction and suggested a lack of clinically significant effect of caffeine on adenosine-induced hyperemia during myocardial SPECT imaging. This article reviews the clinical pharmacology of caffeine, adenosine, and dipyridamole and effect of caffeine on myocardial stress testing using adenosine and dipyridamole in clinical cardiovascular medicine. The limited published data are conflicting, but some recent publications suggest that myocardial perfusion SPECT imaging using adenosine may not be clinically significantly altered by routine consumption of caffeine, such as a cup of coffee. Although prospective randomized studies would be required to obtain a definitive answer to this question, it appears on the basis of some of the studies reviewed in this article that caffeine consumption prior to myocardial perfusion imaging may not necessitate cancellation or rescheduling of adenosine stress testing.     

Diagnosis of coronary artery disease using exercise echocardiography and positron emission tomography: comparison and analysis of discrepant results.

Both exercise echocardiography and rubidium-82 positron emission tomography are used in the detection and characterization of coronary artery disease. This study compared results of both in 74 patients with known coronary anatomy, by use of exercise echocardiography before and after treadmill exercise and positron emission tomography with intravenous dipyridamole-handgrip stress. Significant (greater than 50%) coronary stenoses were present in 70 patients; exercise echocardiography and positron emission tomography each identified 63 patients (sensitivity 90%). Significant stenoses without previous myocardial infarction were present in 34 patients; 29 (85%) were identified by exercise echocardiography and 28 by positron emission tomography (82%, p = NS). Four patients had no significant coronary disease, and were all identified as normal by both methods. Segments were classified as either normal or showing stress or resting abnormalities, and the diagnoses were compared in the territories of the three major coronary arteries. Results were concordant with respect to the presence or absence of coronary disease in 185 of 222 territories (83%). The remaining 37 regions had abnormalities by exercise echocardiography or positron emission tomography but not both. Stress defects were identified by only one of the tests in 24 areas (in 12 [50%], angiographic findings correlated with positron emission tomography). Resting defects were diagnosed by only one modality in 13 regions (angiographic findings correlated with the results of positron emission tomography in 9 [69%] of these). Both exercise echocardiography and positron emission tomography are sensitive for the identification of coronary artery disease, although on a regional basis, positron emission tomography appears to be more specific for the diagnosis of resting perfusion defects.     

ASCI 2010 contrast media guideline for cardiac imaging: a report of the Asian Society of Cardiovascular Imaging cardiac computed tomography and cardiac magnetic resonance imaging guideline working group

To evaluate the accuracy of myocardial perfusion SPECT (MPI) in the detection and allocation of vessel specific perfusion defects (PD) using standard distribution territories in a routine clinical procedure of patients with multivessel disease (MVD). Combined quantitative coronary angiography and fractional flow reserve (QCA/FFR) measurements were used as invasive reference standard. 216 vessels in 72 MVD patients (67 ± 10 years, 28 female) were investigated using MPI and QCA. FFR of 93 vessels with intermediate stenoses was determined. MPI detected significant stenoses according to QCA/FFR findings with a sensitivity of 85%. However, vessel-based evaluation using standard myocardial distribution territories delivered a sensitivity of only 62% (28 MPI+ out of 45 (QCA/FFR)+ findings), with specificity, PPV and NPV of 90, 62 and 90%. 7/17 false positive and 7/17 false negative findings (41%) could be attributed to incorrect allocation of reversible PD to their respective coronary arteries. 6/17 (35%) perfusion territories were classified as false negative when additional fixed PD were present. MPI had reasonable sensitivity for the detection of significant coronary artery disease in patients with multivessel disease. However, sensitivity decreased markedly, when the significance of each individual stenosis was evaluated using standard myocardial supplying territories. In this setting, 41% of false negative and false positive MPI findings resulted from incorrect allocation of reversible perfusion defects to their determining supplying vessel.     

Evaluation of immediate post-stress wall motion on adenosine stress/rest Thallium-201 Gated Myocardial SPECT

As early as 10 min after adenosine stress, immediate post-stress wall motion can be evaluated on adenosine stress/rest Tl-201 gated myocardial SPECT. To widen the applications of Tl-201 in gated SPECT, we investigated the reproducibility of LV parameters (EF, EDV, and ESV), and the diagnostic competency of immediate post-stress wall motion evaluations obtained by adenosine stress/rest Tl-201 gated myocardial SPECT. Myocardial perfusion and wall motion were evaluated using a 5-point scoring system in 20-segment model using Cedas automatic gated software (AutoQUANT 4.3.1). The reproducibilities of LV parameters were examined through repeated acquisition (n=31). Diagnostic competency was evaluated vs. coronary angiography, and multivariate logistic regression analysis was used to determine whether stress abnormal perfusion (SSSp), stress abnormal wall motion (SSSwm), or reversible abnormal wall motion (SDSwm) predict coronary stenosis (> 70%) (n=60). Two standard deviations for immediate post-stress wall motion were smaller than those for rest at EF (8.6 vs. 10.7%) and ESV (6.0 ml vs 8.4 ml). Univariate logistic regression analysis identified SSSp (p=0.006), SSSwm (p=0.016), and SDSwm (p=0.020) are significant predictors, but only SSSp (p=0.013) and SDSwm (p=0.039) were found to be significant by multivariate analysis. In addition, SSSwm or SDSwm were able to find undetected coronary artery disease in 54.5% (6/11) of patients with normal perfusion. We conclude that Tl-201 can be successfully applied to gated SPECT for immediate post-stress wall motion evaluation, and that reversible wall motion abnormality on adenosine stress/rest Tl-201 gated myocardial SPECT is an independent predictor of significant coronary artery disease.     

Real-time perfusion adenosine stress echocardiography versus myocardial perfusion adenosine scintigraphy for the detection of myocardial ischaemia in patients with stable coronary artery disease

BACKGROUND: Real-time perfusion (RTP) contrast echocardiography using low mechanical index power modulation technique allows for simultaneous myocardial perfusion and wall motion analysis. RTP-adenosine stress echocardiography (ASE) could be an alternative to dobutamine-atropine stress echocardiography; more tolerable for the patients and possibly similarly accurate. We aimed to evaluate RTP-ASE for the detection of myocardial ischaemia, compared to 99mTc-sestamibi single-photon emission computed tomography (SPECT). METHODS: Patients with suspected coronary artery disease, admitted to SPECT evaluation, were prospectively invited to participate. Patients underwent RTP imaging (SONOS 5500) using infusion of Sonovue (Bracco, Milano, Italy) before and during ASE. Two separate readers performed off-line analysis of myocardial perfusion and wall motion by RTP-ASE. A perfusion defect was the principal marker of ischaemia. Wall motion assessment was used to evaluate ischaemia in segments with perfusion artefacts. Each segment was attributed to one of the three main coronary vessel areas of interest: the left anterior descending (LAD); the left circumflex (LCx) and the right posterior descending (RPD). Normal SPECT at stress was judged normal at rest. RESULTS: In 33 patients, 99 coronary territories were analysed by SPECT and RTP-ASE. SPECT showed evidence of ischaemia in 9 of 33 patients. For the detection of ischaemia, the overall level of agreement between RTP-ASE and SPECT was 92% in all segments. The level of agreement was 88% in LAD, 97% in LCx and 91% in RPD segments. CONCLUSION: Real-time perfusion-adenosine stress echocardiography using power modulation could be an accurate and feasible tool for evaluation of ischaemia in patients with suspected coronary artery disease. The results from this study need confirmation by a study of a larger patient sample.     

Tl-201 myocardial SPECT in silent myocardial ischemia and angiographically proven coronary heart disease

Silent myocardial ischemia is defined as true myocardial ischemia without angina pectoris in patients with angiographically detected coronary artery disease. In this study 52 patients (46 male, 8 female: mean age 53 years) with a pathological exercise test but no symptoms were investigated. They showed stenosis of 75% or more of the diameter in at least one coronary segment on angiography. Prior to or after catheterization (within 14 days) Tl-201 SPECT was done and evaluated independently of angiography. A clear correlation between angiographically confirmed stenosis and reversible perfusion defects with Tl-201 SPECT was established (62 out of 76 lesions). Furthermore, there was a significant relation between angiographically detected subtotal or total occlusions of coronary vessels and irreversible perfusion defects using Tl-201 SPECT (35 in 44 lesions) (p less than 0.001). In patients with ST depression but without angina pectoris during the exercise test, the Tl-201 SPECT is highly suited to determine the hemodynamic effect of coronary stenoses.     

双嘧达莫与多巴酚丁胺负荷心肌超声造影探测冠脉狭窄的对比研究

目的对比双嘧达莫和多巴酚丁胺负荷心肌超声造影(MCE)探测静息状态下无心肌血流限制性冠脉狭窄的能力.方法用放置"水膨胀”式缩窄器于冠脉主干近端的方法,建立15只慢性多支冠脉狭窄闭胸犬模型.术后7～10d进行静息、双嘧达莫和多巴酚丁胺的小剂量微泡弹丸式注射法MCE,并同步用放射性标记微球测量心肌血流(MBF).以MBF储备≥3为正常和＜3为异常供血区.结果两种药物引起MBF增加,在正常和异常供血区均相近.两种药物负荷时,MCE示异常供血区灌注缺损的范围和程度相同.两种药物作用下异常供血区的峰值声强度(VI)均较正常供血区低(P＜0.05),异常和正常供血区峰值VI比值非常接近;且双嘧达莫和多巴酚丁胺的峰值VI比值均与相应的MBF比值呈良好的线性正相关(r=0.90和0.87,P＜0.0001).结论双嘧达莫和多巴酚丁胺负荷MCE探测冠脉狭窄的能力相近.因此,两者均可用于慢性冠脉狭窄的诊断.     

Diagnostic accuracy of quantitative cardiac MRI evaluation compared to stress single-photon-emission computed tomography

Background: Cardiac MRI (cMRI) perfusion is a promising non-invasive tool to assess myocardial ischemia. The accuracy of quantitative cMRI perfusion has been recently demonstrated, but to date no previous study has compared this technique with stress single-photon-emission computed tomography (SPECT). The aim of this study was to evaluate the diagnostic accuracy of myocardial perfusion reserve (MPR) based on cMRI compared with SPECT. Methods: We examined 24 patients who underwent coronary angiography, stress SPECT and cMRI perfusion. Qualitative assessment of both SPECT and cMRI images, quantification of cMRI perfusion, and quantitative coronary angiography (QCA) were independently performed. MPR was calculated using Fermi deconvolution technique. Accuracy of quantitative and qualitative data was examined to detect > 50% diameter stenosis (DS) by QCA. Results: Qualitative analysis was obtained in 198 segments and quantitative analysis was performed in 171 segments. Significant coronary artery disease (CAD) was present in 81.8% of patients. Visual cMRI assessment yielded sensitivity of 74.4% and specificity of 79.4% to predict > 50%DS, while SPECT showed sensitivity of 67.4% and specificity of 81.3%. The sensitivity for SPECT in the right coronary artery territory and apex was low compared to cMRI. Sensitivity and specificity for detection of significant CAD were 89.5% and 46.6% for MPR (cutoff 1.92). Area under the curve was 0.75 for MPR (P < 0.01). Conclusions: The diagnostic accuracy of qualitative examination of perfusion cardiac MRI and stress SPECT were comparable. The high sensitivity and low operator dependency of quantitative cMRI makes it an attractive tool to evaluate myocardial perfusion.     

腺苷负荷心肌核素显像在冠心病诊断与介入治疗中的作用

目的探讨腺苷负荷心肌核素显像在冠心病诊断及介入治疗中的作用。方法冠心病的可疑患者,行腺苷负荷心肌核素显像,部分患者进行冠脉造影和介入治疗,介入治疗前后进行腺苷负荷心肌核素显像检查对比。腺苷负荷心肌核素显像采用单光子发射断层显像图像采集系统,腺苷总量为840μg/kg静脉泵入,3 min后静脉推注99mTc-MBI925 MBq,90 min后进行心肌断层显像,如果发现心肌显像异常,次日再行静息心肌显像。结果134例冠心病患者,年龄21~85(63.3±14.8)岁,男90例,女44例,进行腺苷负荷心肌核素显像,109例提示有心肌缺血现象,25例正常,诊断阳性率达81.3%。12例患者经过冠状动脉造影,有冠脉狭窄的患者行PCI,前后复查腺苷心肌核素显像,介入后心肌核素血流灌注较介入前明显改善(P<0.01)。结论腺苷负荷心肌核素显像在冠心病的诊断中起着重要的作用,其敏感性与特异性较高,同时在冠心病介入治疗前后疗效评价方面有一定的临床意义。     

Relation between geometric dimensions of coronary artery stenoses and myocardial perfusion reserve in man.

To determine the relation between stenosis anatomy and perfusion in man, 31 patients had quantitative coronary arteriography and positron imaging (PET) with Rb-82 or N-13 ammonia at rest and after dipyridamole-handgrip stress. 10 patients were also studied after angioplasty (total stenoses = 41). Percent narrowing and absolute cross-sectional luminal area were related through a quadratic function to myocardial perfusion reserve determined with PET. Arteriographically determined coronary flow reserve was linearly related to relative myocardial perfusion reserve as expected, based on the derivation of equations for stenosis flow reserve. All of the correlations had considerable scatter, indicating that no single measurement derived by coronary arteriography was a good indicator of perfusion reserve by PET in individual patients. This study provides the relation between all anatomic dimensions of coronary artery stenoses and myocardial perfusion reserve in man, and suggests that PET indicates the functional significance of coronary artery stenoses for clinical purposes.     

Transient ischemic dilatation of the left ventricle with severe post stress left ventricular dysfunction in the setting of severe aortic stenosis and normal coronary arteries

Transient ischemic dilatation (TID) of the left ventricle observed during single photon myocardial perfusion emission computed tomography (SPECT) is an important non-perfusion finding that may not only suggest underlying significant (usually multi-vessel) coronary artery disease (CAD) but also an independent prognostic factor of adverse outcomes regardless of abnormal or normal perfusion finding. We present a patient with no significant epicardial coronary disease who had significant TID and considerable decrease in the left ventricular ejection fraction with left ventricular dilatation after a rest-stress Tc-99 tetrofosmin SPECT study in the setting of severe aortic stenosis. With the advent of gated SPECT imaging the additive value of determining rest and post stress EF, as demonstrated in this case, aided in the recognition of TID and transient decrease in the left ventricular ejection fraction. These are not necessarily related to obstructive epicardial coronary disease, but are a result of severe aortic valve disease causing subendocardial ischemia in the setting of multilple other non-ischemic etiologies of TID such as left ventricular hypertrophy and diabetes mellitus.     

Added value of rest to stress study for recognition of artifacts in perfusion cardiovascular magnetic resonance.

BACKGROUND: The objective was to determine whether rest perfusion (RP) adds to stress perfusion (SP) and late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) for detection of impaired coronary flow reserve. METHODS: We enrolled patients (n=45) referred for myocardial perfusion SPECT (MPS) for adenosine CMR stress. SP, RP and LGE images were obtained with 99mTc sestamibi injection during a single adenosine infusion. Segmental perfusion and confidence scores were recorded for SP-LGE interpreted with and without RP. CMR agreement with MPS was determined. RESULTS: MPS was normal in 653 and abnormal in 67 segments. SP-LGE CMR interpreted without RP was normal in 407, abnormal in 313 segments, and showed poor agreement with MPS (58%). Two hundred thirty-seven segments were changed to normal using data from RP, improving agreement (87%, p<0.0001). Reader confidence was low in 33 patients with SP-LGE and improved in 26 patients using SP-RP-LGE, where 37/45 were read with high confidence. Artifact was present in 68% of SP CMR and accounted for false positive studies. CONCLUSION: Agreement between single stress adenosine CMR and MPS is optimized by combining RP, LGE and SP CMR. Addition of RP CMR to SP-LGE CMR improved agreement with MPS and reader confidence. Improved CMR pulse sequences may change the role of rest perfusion data.