Clinical significance of dipyridamole Tl-201 emission computed tomography perfusion abnormality for evaluating pathophysiological and pathological aspects in hypertrophic cardiomyopathy

A dipyridamole-induced Tl-201 perfusion abnormality was evaluated from its clinical features, echocardiography and myocardial histopathology in 39 patients with hypertrophic cardiomyopathy (HCM). From the findings of Tl-201 emission computed tomography (ECT), subjects were divided into three groups: group 1 (n = 16) which did not show a perfusion abnormality in the hypertrophic region; group 2 (n = 12) which showed a perfusion defect on the initial image with complete redistribution on the delayed image; and group 3 (n = 11) which showed a persistent perfusion defect--this group included most patients who revealed partial and/or incomplete redistribution. Echocardiography revealed that group 2 showed a marked asymmetrical septal hypertrophy and an incidental obstructive pattern, and that group 3 had a significantly dilated left ventricular diastolic dimension and a decreased percentage of fractional shortening. Group 3 also showed frequent ventricular tachycardia and a familial history of cardiomyopathy. As for the myocardial biopsy findings, group 3 had significantly advanced myocardial fibrosis, the percentage being 6.0 +/- 3.1% in group 1; 5.5 +/- 2.5% in group 2; and 11.9 +/- 3.4% in group 3. Thus, it was concluded that the persistent perfusion defect on dipyridamole stress Tl-201 ECT testing is an important finding corresponding to the advanced clinical and pathological aspects of HCM.     

Medium- to long-term prognostic impact of dipyridamole thallum-201 myocardial single-photon emission computed tomography in elderly patients.

Dipyridamole thallium-201 single-photon emission computed tomography (SPECT) has not been extensively evaluated for risk stratification and the medium- to long-term prognostic value in elderly cardiac patients who are unable to exercise. The present study group comprised 210 consecutive patients aged at least 70 years with known or suspected coronary artery disease (CAD). The SPECT findings were classified as a reversible, fixed, or combined (reversible and fixed) defect. Of the 210 patients, 201 (77+/-5 years, 85 male) were successfully followed for 49+/-26 months. Thirteen (7%) patients had cardiac events: cardiac death (n=10), non-fatal myocardial infarction (n=1), or coronary artery bypass grafting (n=2). Cardiac events occurred in 3 of 112 patients with normal SPECT and in 10 of 89 patients with an abnormal scan (0.7% /year vs 2.8% /year, p=0.01). Stepwise Cox regression analysis revealed that the significant predictors of cardiac events were combined defects (relative risk 7.3) and the number of defect areas (relative risk 4.4). The predictive value of dipyridamole thallium-201 SPECT is maintained over 4 years in mixed populations of elderly CAD patients who are unable to exercise.     

Hypertrophic non-obstructive cardiomyopathy assessed by dipyridamole thallium single photon emission computed tomography: comparisons with hypertrophic cardiomyopathy with a dilated heart

Thallium-201 (Tl) single photon emission computed tomography (SPECT) after dipyridamole infusion (0.56 mg/kg) was performed in 23 patients with hypertrophic non-obstructive cardiomyopathy (HNCM) and in seven patients with HCM simulating dilated cardiomyopathy (HCM-DCM) to clarify the mechanism and clinical significance of decreased coronary vasodilatory reserve. The coronary vasodilatory reserve in the hypertrophied area assessed by SPECT was compared with the findings of echocardiography, left ventriculography and endomyocardial biopsy. 1. Eleven patients with HNCM had no perfusion defects in the hypertrophied area (group I), but the other 12 patients (52.2%) had such defects (group II). All seven patients with HCM-DCM had perfusion defects in the anterior or septal walls (group III). Redistribution was observed in 11 of the 12 patients in group II and in three of the seven patients in group III. 2. The regional washout rate was relatively low in the upper septum in group II and in the anterior wall and upper septum in group III. Thus, coronary vasodilatory reserve in the hypertrophied area was decreased in groups II and III. 3. Echocardiographically, the degree of hypertrophy did not differ between groups I and II, but the latter had significantly greater left ventricular diastolic dimension (42.3 mm vs 49.5 mm: p less than 0.05) and lower percent fractional shortening (%FS) (43.7% vs 35.6%: p less than 0.05). However, group III showed thinner left ventricular wall, much greater diastolic dimension (60.9 mm vs 49.5 mm: p less than 0.05), and lower %FS (24.0% vs 35.6%: p less than 0.05) than did those of group II. 4. On left ventriculography, those in group II showed larger left ventricular end-diastolic volume index (93.9 ml/m2 vs 79.7 ml/m2: p less than 0.05) than that of group I. Left ventricular ejection fraction showed the same tendency, but this was not statistically significant. 5. On endomyocardial biopsy, the specimens of the patients in group II had significantly higher percent fibrosis than did those of group I (11.4% vs 6.8%: p less than 0.05). These findings suggest that the mechanism of decreased coronary vasodilatory reserve in the hypertrophied area may be related to myocardial fibrosis, and this decrease may induce left ventricular dysfunction and compensatory dilatation.     

Myocardial perfusion abnormalities in patients with hypertrophic cardiomyopathy: assessment with thallium-201 emission computed tomography

Myocardial ischemia may play a critical role in the symptomatic presentation and natural history of hypertrophic cardiomyopathy (HCM). To assess the relative prevalence and functional significance of myocardial perfusion abnormalities in patients comprising the broad clinical spectrum of HCM, we studied 72 patients (ages 12 to 69 years, mean 40) using thallium-201 emission computed tomography. Imaging was performed immediately after maximal exercise and again after a 3 hr delay. Regional perfusion defects were identified in 41 of the 72 patients (57%). Fixed or only partially reversible defects were evident in 17 patients, 14 of whom (82%) had left ventricular ejection fractions of less than 50% at rest. Twenty-four patients demonstrated perfusion defects during exercise that completely reversed at rest; all had normal or hyperdynamic left ventricular systolic function (ejection fraction greater than or equal to 50%). Perfusion abnormalities were present in all regions of the left ventricle. However, the fixed defects were observed predominantly in segments of the left ventricular wall that were of normal or only mildly increased (15 to 20 mm) thickness; in contrast, a substantial proportion (41%) of the completely reversible defects occurred in areas of moderate-to-marked wall thickness (greater than or equal to 20 mm, p less than .001). Neither a history of chest pain nor its provocation with treadmill exercise was predictive of an abnormal thallium study, since regional perfusion defects were present in 10 of 18 (56%) completely asymptomatic patients, compared with 31 of 54 (58%) symptomatic patients. These data indicate that myocardial perfusion abnormalities occur commonly among patients with HCM. Fixed or only partially reversible defects suggestive of myocardial scar and/or severe ischemia occur primarily in patients with impaired systolic performance. Completely reversible perfusion abnormalities occur predominantly in patients with normal or supranormal left ventricular systolic function. Such dynamic changes in regional thallium activity may reflect an ischemic process that contributes importantly to the clinical manifestations and natural history of HCM.     

Improved specificity of myocardial thallium-201 single-photon emission computed tomography in patients with left bundle branch block by dipyridamole

Reduced septal uptake of thallium-201 during exercise is frequently observed in patients with left bundle branch block (LBBB) and normal coronary arteries. This may reflect normal coronary autoregulation in response to lower septal oxygen demand; thus, dipyridamole, which uniformly exploits flow reserve, would be more accurate for diagnosis of coronary artery disease (CAD). Sixteen patients with LBBB underwent exercise and dipyridamole thallium-201 single-photon emission computed tomography and coronary angiography within 3 months. Sensitivity for detection of left anterior descending CAD (greater than 50% stenosis) was 0.83 for exercise and 1.00 for dipyridamole. Specificity was 0.30 (visual) or 0.20 (quantitative analysis) for exercise and 0.80 (visual) or 0.90 (quantitative) for dipyridamole (p less than 0.05). Dipyridamole combined with quantitative analysis also improved specificity of CAD detection overall (p less than 0.01). These data demonstrate that pharmacologic vasodilation is more accurate than exercise when diagnosing CAD by myocardial perfusion scintigraphy in patients with LBBB.     

Hemodynamic and prognostic value of thallium-201 myocardial imaging in patients with dilated cardiomyopathy

We studied 70 patients with dilated cardiomyopathy to determine whether extent of perfusion defect on thallium imaging could be related to the hemodynamics and prognosis of the patients. Patients were divided into three groups according to the extent of perfusion defect, i.e., Grade I: no perfusion defect (n = 19), Grade II: apical perfusion defect (n = 22), and Grade III: extensive perfusion defect (n = 29). The patients of Grade III demonstrated marked hemodynamic deterioration compared with those of Grade I and II. Three-year survival rate showed lower value in proportion to the extent of perfusion defect (P less than 0.05). Death from progressive heart failure tended to occur in patients with extensive perfusion defect (P less than 0.05). In patients of Grade III, the perfusion defect extended mainly to the posterolateral segment. Although autopsy studies showed increased fibrosis in the left ventricular wall in these patients, the extension of the fibrosis was not related to that of fibrosis. Moreover, the perfusion defect had regressed in three of 18 patients in the follow-up examination. These results indicate that the extent of perfusion defect on thallium imaging may be of value in non-invasive evaluation and prediction of the prognosis in patients with dilated cardiomyopathy. Distribution of the perfusion defect was, however, not related to that of myocardial fibrosis.     

Functional significance of myocardial perfusion defects induced by dipyridamole using thallium-201 single-photon emission computed tomography and two-dimensional echocardiography

The mechanisms responsible for inhomogeneous myocardial blood flow after oral administration of a large dose (300 mg) of dipyridamole were assessed in 27 patients with serial thallium-201 single-photon emission computed tomography (SPECT) and simultaneous 2-dimensional echocardiograms. Myocardial tomographic images were obtained 50 minutes and 3 to 4 hours after administration of dipyridamole. Two-dimensional echocardiograms were recorded at baseline and then every 15 minutes for 60 minutes. Dipyridamole caused only a mild reduction in blood pressure (from 129 +/- 18 to 126 +/- 16 mm Hg) and a mild increase in heart rate (from 69 +/- 15 to 73 +/- 4 beats/min). Sixteen patients had perfusion defects after dipyridamole by SPECT, which underwent partial or total filling-in. Fourteen of these patients (87.5%) had either a new abnormality or further deterioration of a preexisting wall motion abnormality by 2-dimensional echocardiography, and thus were considered to have developed transient ischemia during dipyridamole administration. Ten of 11 patients (91%) with normal perfusion or fixed defects by SPECT had no further deterioration in wall motion after oral dipyridamole, and were thus considered to have no evidence of myocardial ischemia. In conclusion, most patients with transient thallium-201 defects after dipyridamole develop transient worsening of resting wall motion by 2-dimensional echocardiography, suggestive of true myocardial ischemia. Because myocardial oxygen demand, as indicated by the heart rate-blood pressure product, did not change significantly, the mechanism of myocardial ischemia in these patients is likely to be diminished regional blood flow related to a "subendocardial steal" induced by dipyridamole.     

The prognostic significance of left ventricular response to isoproterenol infusion in patients with dilated cardiomyopathy

To evaluate the prognostic value of the left ventricular response to isoproterenol infusion in patients with dilated cardiomyopathy (DCM), 25 patients, 17 men and eight women, were studied. According to responses of left ventricular function to isoproterenol (0.02 microgram/kg/min), the patients were classified in two groups: the normal response group, in which fractional shortening increased by more than 10% (n = 10); and the low response group, in which fractional shortening increased by 10% or less (n = 15). A follow-up spanning four to 40 months with an average of 21 months disclosed that six patients died, two deteriorated, and six had no change in the low response group, while seven patients were improved, three stabilized, and no one deteriorated or died in the normal response group. There was a difference in the clinical courses of the two groups. Thus, the left ventricular response to isoproterenol proved useful in predicting the course of DCM.     

快速性心律失常对扩张型心肌病患者预后的影响

目的　探讨快速性心律失常 ( TCA)对扩张型心肌病 ( DCM)患者预后的影响。方法　对 4 2例 DCM伴 TCA患者 ,住院期间是否发生死亡 ,分为死亡组与存活组 ,分析两组临床特征及心电图。结果　死亡组室性心动过速 ( VT)发作频率快、阵数高、多形性 VT的发生率高 ( P <0 .0 5～ 0 .0 0 1) ;死亡组左心室射血分数 ( L VEF)明显低于存活组 ( P <0 .0 0 1)。结论　 DCM伴 VT,具有发作频率快、阵数高、多形性 VT的特点 ,是 DCM患者猝死的危险因素     

扩张性心肌病心电图表现与临床意义探讨

目的：探讨心电图对扩张性心肌病（DCM）的诊断及预后的价值。方法：分析83例DCM病人和86例健康体检者心电图,分析参数包括QRS时限,RV5电压,异常QRS波切迹,异常Q波,心律失常,及ST-T改变。83例扩心病人按QRS时限分为A组（41例,QRS时限〈0.10秒）、B组（14例,0.10秒〈QRS时限〈0.12秒）、C组（20例,QRS时限〉0.12秒）,比较各组纽约心脏病学会（NYHA）分级情况及左、右室内径差异。结果：与健康体检者比较,DCM病人QRS时限明显增宽[（0.086±0.02）比（0.119±0.04）],RV5电压明显减低[（1.58±0.51）比（1.08±0.72）],异常QRS波切迹（5.8%比54.1%）、异常Q波（1.4%比23%）、心律失常（2.9%比67.2%）及ST-T改变（7.2%比100%）发生率明显增加（P〈0.05～0.01）。DCM患者A、B、C组中,心功能II级,C组显著少于A组（20.0%比48.1%）,左室舒张内径C组显著大于A组[（7.03±0.67）mm比（5.68±0.58）mm,P〈0.05]。结论：扩心病患者心电图有显著改变,QRS时限与心功能及左室内径有一定关系,对临床诊断有一定参考价值。     

Diagnostic accuracy of multidetector computed tomography coronary angiography in patients with dilated cardiomyopathy.

OBJECTIVES: The purpose of this work was to assess the safety, feasibility, and diagnostic accuracy of multidetector computed tomography (MDCT) in dilated cardiomyopathy (DCM) of unknown etiology. BACKGROUND: Multidetector computed tomography is an appropriate noninvasive tool for coronary artery disease (CAD) detection, particularly in patients with low probability of the disease, such as patients with DCM of unknown origin. METHODS: We studied 61 unknown origin DCM patients (ejection fraction: 33.9 +/- 8.6%, group 1) and 139 patients with normal cardiac function with indications for coronary angiography (group 2, control population). All underwent coronary MDCT and angiography. Multidetector computed tomography images were acquired by light speed 16-slice computed tomography. The degree of stenosis was estimated in 15 coronary artery segments according to the American Heart Association model. RESULTS: In group 1, no MDCT-related complications were found, while 10 complications were associated with conventional angiography (p = 0.001). Overall feasibility of coronary artery visualization was 97.2% (863 of 888 segments). The most frequent cause of artifacts was interference from a hypertrophic cardiac venous system (10 artifacts, 40%). In group 2, overall feasibility was 96.1% (p = NS vs. group 1). In group 1, all cases with normal (44 cases) or pathological (17 cases) coronary arteries by conventional coronary angiography were correctly detected by MDCT, with, in 1 case, disparity of stenosis severity. In group 1, sensitivity, specificity, and positive and negative predictive values of MDCT for the identification of >50% stenosis were 99%, 96.2%, 81.2%, and 99.8%, respectively. In group 2, sensitivity and negative predictive values were lower than in group 1 (86.1% vs. 99% and 96.4% vs. 99.8%, respectively); specificity (96.4%) and positive predictive value (86.1%) were not significantly different versus group 1. CONCLUSIONS: Multidetector computed tomography is feasible, safe, and accurate for identification of idiopathic versus ischemic DCM, and may represent an alternative to coronary angiography.     

The prognostic nutritional index might predict clinical outcomes in patients with idiopathic dilated cardiomyopathy

Background and aimsThe prognostic nutritional index (PNI) had been associated with adverse outcomes in numerous clinical conditions. However, its influence on idiopathic dilated cardiomyopathy (DCM) was not determined. This aim of this study was to determine the predictive ability of PNI in patients with idiopathic DCM.Methods and resultsA total of 1021 consecutive patients with idiopathic DCM were retrospectively included and divided into three groups based on admission PNI tertiles: <41.7 (n = 339), 41.7–47.3 (n = 342), >47.3 (n = 340). The association of PNI with in-hospital major adverse clinical events (MACEs) and death during follow-up was evaluated. In-hospital mortality (2.9% vs. 1.5% vs. 0.0%, respectively; p = 0.006) and MACEs (13.6% vs. 6.7% vs. 3.5%, respectively; p < 0.001) decreased from the lowest to the highest PNI tertile. The optimal cut-off value of PNI to predict in-hospital MACEs was 44.0 (area under the curve: 0.689; 95% confidence interval [CI]: 0.626–0.753; p < 0.001). Multivariate analysis showed that a PNI≤44.0 was an independent risk factor of in-hospital MACEs (odd ratio: 2.86; 95% CI: 1.64–4.98; p < 0.001) and all-cause mortality at a median follow-up of 27 months (hazard ratio: 1.67; 95% CI: 1.11–2.49; p = 0.013). In addition, patients with a PNI≤44.0 had a lower cumulative survival rate during follow-up (log-rank: 35.62; p < 0.001).ConclusionThe PNI was an independent risk factor for in-hospital MACEs and all-cause mortality at a median follow-up of 27 months in patients with idiopathic DCM; hence, it may be considered a tool for risk assessment.     

Dobutamine stress echocardiography compared with dipyridamole thallium-201 single-photon emission computed tomography in detecting coronary artery disease

To compare the diagnostic value of dobutamine stress echocardiographywith dipyridamole thallium-201 single-photon emission computedtomography (SPECT) in detecting coronary artery disease (CAD),we performed both tests on 54 patients who also underwent coronaryarteriography. Dobutamine was infused at an incremental regimenof 5,10,20,30 and 40 µg. kg^-1. min^-1. Dipyridamole wasinfused at a rate of 0.14 mg. kg^-1. min^-1 over 4 min. Dobutaminestress echocardiography detected 40 (93%) and SPECT 42 (98%,P=ns) of the 43 patients with significant CAD, defined as (greaterthan or equal) 50% diameter stenosis. The specificity was 73%(8 of 11) for both tests. The sensitivity for detecting individualcoronary artery stenosis with dobutamine stress echocardiographywas 81% (30 of 37) for the left anterior descending artery,75% (24 of 32) for the right coronary artery, and 61% (17 of28) for the left circumflex artery. For SPECT it was 89%, 97%(P>0.05 vs dobutamine stress echocardiography) and 75%, respectively. Among the 97 stenotic coronary arteries, 17 had mild to moderatestenosis (50%-69% diameter stenosis) and 80 had severe stenosis($$70% diameter stenosis). With dobutamine stress echocardiography,53% of the arteries with mild to moderate stenosis were identifiedvs 78% of those with severe stenosis (P<0.05). With SPECT,the sensitivity was 82% (14 of 17) in mild to moderate stenosisand 89% (71 of 80) in severe stenosis (P=ns). No major sideeffects occurred during either test. Thus, both dobutamine stressand SPECT are highly sensitive for detection and localizationof CAD. However, the sensitivity of dobutamine stress is affectedby the level of stenosis severity.     

扩张型心肌病患者甲状腺素水平变化及临床意义

目的　探讨扩张型心肌病患者甲状腺素水平变化的临床意义。　方法　纠正心衰的同时加甲状腺素 5mg 天 ,用放射免疫法测定治疗前后TT3、TT4 、FT3、FT4 、TSH ,同时用超声心动图测定扩张型心肌病患者治疗前后的左室射血分数。　结果　治疗前TT3为 0 70nmol L± 0 32nmol L ,显著低于对照组的 2 32nmol L± 1 15nmol L ,加用甲状腺素 5mg 天治疗后为 2 12nmol L± 0 92nmol L。左室射血分数治疗前为 0 2 5± 0 0 2 ,治疗后为 0 4 9± 0 0 4。　结论　扩张型心肌病的严重程度与甲状腺素的水平密切相关。     

Assessment of regional wall motion and myocardial flow in patients with dilated cardiomyopathy using Tl-201 SPECT during dobutamine infusion

The present study clarified the relationship between wall motion and myocardial flow in dilated cardiomyopathy (DCM). Two-dimensional echocardiography (2-DE) was performed in 14 patients before and after dobutamine (DOB) drip infusion (8 micrograms/kg/min). Thallium-201 emission computed tomography (ECT) was performed after dobutamine infusion and three hours thereafter. The left ventricle was divided into nine segments. In each segment, the degrees of defects were scored from 0 (normal) to 3 (complete defect), and the severity of wall motion abnormalities was scored from 0 (normal) to 3 (akinesis) by visual inspection. 1. Perfusion defects on ECT images were observed during dobutamine infusion in all patients. Redistribution was observed in nine of 14 (64%) patients. 2. During infusion, 38 (81%) of 47 segments without defects showed normal wall motion, but 44 (86%) of 51 segments with defects showed wall motion abnormalities. 3. Redistribution was observed in 18 (35%) of 51 segments, and these segments showed lower incidence of wall motion abnormalities as compared to the other segments (94% vs 45%, p less than 0.001). 4. After infusion, the segments with redistribution frequently showed improved wall motion as compared to the other segments (56% vs 18%, p less than 0.05). These results indicate that redistribution on the ECT image is observed in some patients with dilated cardiomyopathy after dobutamine administration. This may be due to the capacity of the drug to increase myocardial flow in proportion to the increase of oxygen demand.     

The independent prognostic value of contractile and coronary flow reserve determined by dipyridamole stress echocardiography in patients with idiopathic dilated cardiomyopathy

The aim of this study was to evaluate the prognostic value of Doppler echocardiographically derived coronary flow reserve (CFR) in assessing inotropic response in patients with idiopathic dilated cardiomyopathy (IDC). One hundred thirty-two patients with IDC (90 men; mean age 62 +/- 11 years) were evaluated by transthoracic dipyridamole (0.84 mg/kg in 10 minutes) stress echocardiography. All patients had ejection fractions <40% (mean 33 +/- 7%) and angiographically normal coronary arteries, with New York Heart Association class 0.25. All patients were followed for a median of 24 months. Mean CFR was 2.0 +/- 0.5. On individual patient analysis, 48 patients had normal CFR (>2), and 84 had abnormal CFR. The mean wall motion score index at rest was 2.0 +/- 0.33 and decreased to 1.8 +/- 0.4 at peak dipyridamole dose (p <0.000). Forty-two patients (32%) had inotropic reserve. During follow-up, 19 patients died, and 34 showed worsening of New York Heart Association class. The worst outcomes were observed in those patients with abnormal CFR and no inotropic reserve with high-dose dipyridamole. In a Cox model, mitral insufficiency (hazard ratio [HR] 1.7, 95% confidence interval [CI] 1.1 to 2.8), New York Heart Association class (HR 2.0, 95% CI 1.1 to 3.7), abnormal CFR (HR 2.8, 95% CI 1.0 to 8.5), wall motion score index at rest (HR 3.5, 95% CI 1.3 to 9.8), and the absence of inotropic reserve with high-dose dipyridamole (HR 2.3, 95% CI 1.06 to 5.1) were independent predictors of survival. In conclusion, in patients with IDC, CFR is often impaired. Reduced CFR and the absence of an inotropic response during vasodilator stress are additive in predicting a worse prognosis.     

The prognostic value of positron emission tomography/computed tomography in rheumatoid arthritis patients with methotrexate-associated lymphoproliferative disorders

Recently, methotrexate-associated lymphoproliferative disorders (MTX-LPDs) in rheumatoid arthritis (RA) have been found to commonly occur in association with iatrogenic immunodeficiency. Several factors have been reported to be related to the prognosis. We herein investigate the efficacy of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in predicting the prognosis of MTX-LPD. We performed a retrospective analysis of the clinical features, characteristics, and outcomes of 18 patients with MTX-LPDs who were treated from 2004 to 2015. All of the patients were diagnosed with MTX-LPD based on the histological examination of biopsy specimens. Spontaneous regression was detected after the cessation of MTX in 5 of 18 cases (28%). The maximum standardized uptake value (SUVmax) of the FDG uptake on PET/CT was significantly lower, and the maximum size of the LPD-associated tumor was significantly smaller among the patients who showed spontaneous regression (p?=?0.01, p?=?0.04, respectively). Both the SUVmax and the maximum tumor size were related to better overall survival (p?=?0.02, p?=?0.04, respectively). Thus, PET/CT can be used to predict spontaneous regression and the prognosis at the diagnosis of MTX/LPD. Cases that showed spontaneous regression never relapsed during the follow-up period, despite the usage of several anti-rheumatoid arthritis drugs, including biological agents. The early detection of LPDs and the early cessation of MTX are important for the management of RA patients. An evaluation by F-FDG-PET/CT can be useful for predicting spontaneous regression and the prognosis.     

Usefulness of exercise Tl-201 myocardial scintigraphy: comparison with positron emission tomography

To evaluate the usefulness of exercise Tl-201 myocardial scintigraphy, we performed positron emission tomography and conventional exercise Tl-201 emission computed tomography (ECT) in 33 patients with old anterior myocardial infarction (Q-MI: 24, non Q-MI: 9). N-13 ammonia was used as a blood flow tracer, and imaging was performed at rest and after multistage, symptom-limited ergometer exercise. After the administration of F-18 deoxyglucose (FDG) at rest in the fasting state, metabolic imagings were performed to evaluate regional exogenous glucose utilization. Tl-ECT showed fixed defects in 19 of the 33 patients, redistribution of the tracer in nine and no defects in five. All patients having partial or complete redistribution on Tl-ECT showed exercise-induced ischemia on PET with N-13 ammonia and an increased uptake of FDG in the hypoperfused region, suggesting the presence of ischemic but potentially salvageable tissues. In addition, PET with N-13 ammonia detected periinfarct ischemia in nine of the 19 with fixed defects on Tl-ECT, and increased uptakes of FDG were observed in eight of the 19. These results indicate that Tl-ECT may underestimate myocardial viability in clinically infarcted regions. Further studies are needed to determine whether restoring coronary flow improves wall motion in regions with fixed defects on Tl-ECT.