Diagnosis of acute myocardial infarction in patients undergoing open heart surgery: a comparison of serial myocardial imaging with cardiac enzymes, electrocardiography, and vectorcardiography.

In 44 consecutive patients undergoing elective open heart surgery (OHS), serial electrocardiograms (ECG), vectorcardiograms (VCG), serum CPK, cardiac isoenzymes (CPKMB), and myocardial images using Tc-99m pyrophosphate were obtained, before and after the operation, for the detection of acute myocardial infarction (AMI). Twenty-nine patients developed one or more positive tests postoperatively. Two patients had positive myocardial scintiscans; both had other evidence of infarction. Conversely, the appearance of CPKMB, or new ECG and VCG changes, occurred frequently without evidence of infarction, and were not associated with the development of a positive scintiscan. The results show that false-negative results are infrequent in patients imaged early after OHS, and that cardiac surgical procedures do not cause a high incidence of false-positive scintigrams. Consequently, radionuclide imaging for AMI offers an important adjunct for excluding acute infarction following open heart surgery.     

Comparison of Tc-99m pyrosphosphate and Tc-99m hydroxymethylene diphosphonate in acute myocardial infarction: concise communication

A clinical comparison between a new bone seeking radiopharmaceutical, Tc-99m hydroxymethylene diphosphonate (TcHMDP) and the standard agent, Tc-99m pyrophosphate (TcPPi), was performed in 18 patients with acute myocardial infarction. Each patient was imaged initially with either TcHMDP or TcPPi, and imaged 24 hr later with the other tracer. All 18 patients had images positive for acute myocardial infarction with TcPPi, whereas 16 of 18 patients (89%) had positive studies with TcHMDP. The TcPPi images were graded significantly superior to those obtained with TcHMDP in 61% of the patients, and they were equal in 33%. In only one patient (6%) was TcHMDP better. The results indicate that compared with TcHMDP, TcPPi not only has a superior sensitivity for acute myocardial infarction but also has a significantly increased intensity of uptake in positive areas. TcPPi remains the agent of choice for myocardial infarct imaging.     

Comparison of technetium-99m pyrophosphate and technetium-99m methylene diphosphonate with variable amounts of stannous chloride in the detection of acute myocardial infarction

The authors prospectively compared the ability of Tc-99m pyrophosphate (PYP) and Tc-99m methylene diphosphonate (MDP) to detect acute myocardial infarctions. The agents used were PYP (12 mg) with 3.4 mg of stannous chloride, MDP (10 mg) with 1.0 mg of stannous chloride, and MDP (10 mg) with 3.4 mg of stannous chloride. Imaging was performed on three consecutive days on 34 patients with proven myocardial infarctions, using the same agent on the first and third days of the study and an alternate agent on the second day. Agents were assigned randomly to each of six groups of patients. First images were obtained an average of 3.7 days (range, one to six days) following myocardial infarction. Seventeen of 23 patients (75%) had images positive for acute myocardial infarction with Tc-99m PYP, whereas only two of 21 patients (9.5%) had positive studies with Tc-99m MDP with 3.4 mg of stannous chloride and one of 24 patients (4.2%) had positive studies with Tc-99m MDP and 1.0 mg of stannous chloride. All three myocardial infarctions detected by Tc-99m MDP were extensive and transmural. When MDP and PYP were both positive in the same patient, the apparent size of the myocardial infarction was much smaller with the MDP. It is concluded that MDP can detect only large myocardial infarctions, has poor localization in the infarcted tissue, and varying the stannous chloride content of the preparation does not improve the ability of MDP to detect acute myocardial infarctions.     

Quantification of myocardial infarct size by technetium-99m pyrophosphate single photon emission computed tomography

Myocardial infarct size in 41 patients with the first attack of acute transmural myocardial infarction (MI) was assessed by technetium-99m pyrophosphate single photon emission computed tomography (99mTcPYP-SPECT). A ratio of the number of voxels of 99mTcPYP uptake into the infarct area to that into the thorax was calculated as a parameter of MI size. The ratio was positively correlated with both peak CPK activity (r = 0.53, p less than 0.005, n = 24) and extent score in 201TI-SPECT (r = 0.70, p less than 0.005, n = 14) significantly in patients with anterior MI but not in patients with inferior MI. There was also significant negative correlation between the ratio and the left ventricular ejection fraction (LVEF) measured by RI angiography in both acute (r = -0.67, p less than 0.005, n = 18) and chronic (r = -0.75, p less than 0.005, n = 25) phases in patients with anterior MI. Recovery in LVEF at chronic phase was noted in patients with small anterior MI but not with large anterior MI. 8 of 14 patients with inferior MI had right ventricular MI, that might have affected evaluation of MI size and resulted in no correlation between variables. It was suggested that 99mTcPYP-SPECT was a useful method to evaluate MI size and to predict prognosis of cardiac function in patients with anterior MI but not in patients with inferior MI.     

The significance of calcific valvular heart disease in Tc-99m pyrophosphate myocardial infarction scanning: radiographic, scintigraphic, and pathological correlation.

Technetium-99m pyrophosphate (PPi) is currently considered the best scanning agent for the diagnosis of acute myocardial infarction. False-positive scans have been reported in association with unstable angina, alcoholic cardiomyopathy, and ventricular aneurysms. In this study, 86% of patients (12/14) with either calcific aortic or mitral valvular heart disease had positive PPi cardiac scintiscans and the location of the PPi uptake was limited to the calcific valve in all (9/9) of the patients who underwent valve replacement surgery. Six patients with valvular disease without radiologic evidence of calcium had negative PPi heart images. Three of these patients had surgical valve replacement, and in none was there increased uptake in the resected valve. Seventy-five percent of the patients with calcified aortic valves had localization of the PPi activity to the area of the aortic valve, whereas 50% of the patients with calcified mitral valves showed a diffuse pattern of uptake on the cardiac image. In vitro demonstration of increased radioactivity in surgically removed cardiac valves warrants the conclusion that Tc-99m PPi is taken up by calcified heart valves. We conclude that while PPi heart scanning is a sensitive indicator of acute myocardial infarction, false-positive scans can occur in the presence of calcific valvular disease, due to localization of PPi in the calcified portion of the valve.     

99m Tc－M IBI心肌灌注断层显像对实验性心肌梗塞的评价

目的：评价９９ｍ锝一甲氧基异丁基异腈（９９ｍＴｃ－ＭＩＢＩ）ＳＰＥＣＴ显像对心肌梗塞范围的估测及硝酸甘油介入后对存活心肌检测的价值。材料和方法：７条杂种犬通过结扎冠状动脉造成心肌梗塞模型，分别在实验第一天及实验第七天行９９ｍＴｃ－ＭＩＢＩＳＰＥＣＴ静息显像及硝酸甘油介入９９ｍＴｃ－ＭＩＢＩ心肌显像。用圆周剖面法定量分析短轴６个断面心肌缺损面积大小。结果：末次显像缺损面积与病理梗塞面积有良好相关性（ｒ＝０．８６和ｒ＝０．８７分别为硝酸甘油介入前后心肌缺损面积与病理梗塞面积的相关系数），末次显像与首次显像相比缺损面积明显缩小（Ｐ＜０．０５），硝酸甘油介入后心肌显像的平均缺损面积在首次和末次显像均明显减小（Ｐ＜０．０１），且缺损区的平均计数在硝酸甘油介入后均明显增高（Ｐ＜０．０５）。结论：９９ｍＴｃ－ＭＩＢＩ心肌断层显像是了解急性心肌梗塞范围的较好手段及硝酸甘油介入９９ｍＴｃ－ＭＩＢＩＳＰＥＣＴ显像可以提高检测低灌注区残存的存活心肌。     

Localization of myocardial disorders other than infarction with 99mTc-labeled phosphate agents.

Myocardial studies with 99mTc-labeled phosphate agents were obtained in 20 patients without demonstrable cardiovascular disease, 24 patients with unstable arteriosclerotic heart disease (ASHD) without acute infarction, and six patients with myocardiopathy. The patients without cardiovascular disease showed no localization or tracer; the patients with unstable ASHD and without acute infarction showed nonfocal ill-defined accumulation of tracer; and the patients with myocardiopathy showed diffuse accummulation of tracer throughout the confines of an enlarged cardiac outline. Careful evaluation of both the distribution and intensity of the activity, in conjunction with the clinical picture, allows differentiation among these disease processes. Since ischemic areas around infarcted tissue may show increased activity, the value of this technique for sizing acute myocardial infarction may be limited.     

Selective uptake of 99mTc complexes and 67Ga in acutely infarcted myocardium.

The suitability of various radiopharmaceuticals (99mTc-tetracycline analogs, 99mTc-glucoheptonate, 99mTc-diphosphonate, and 67Ga-citrate) for use in imaging acute myocardial infarction was assessed by determining their biologic distributions in experimentally infarcted dogs. The highest infarct-to-normal myocardial concentration ratio was found with 99mTc-diphosphonate (27.9:1); the highest infarct-to-liver ratio was also found with 99mTc-diphosphonate (15.9:1). The infarct-to-bone ratio, however, was 0.4:1 with 99mTc-diphosphonate. There was an excellent positive linear correlation between blood-flow reduction and uptake of the radiopharmaceutical after a threshold reduction in blood flow with 99mTc-glucoheptonate and 99mTc-tetracycline. Technetium-99m-tetracycline accumulated only in infarcted tissue while 99mTc-diphosphonate was increased in both ischemic and infarcted tissue. Thus, 99mTc-diphosphonate has characteristics best suited for scintigraphic imaging. Since 99mTc-tetracycline accumulates only in infarcted tissue, however, this tracer more accurately defines the size of an acute infarction.     

Acute myocardial infarction imaged with 99mTc-stannous pyrophosphate and 201Tl: a clinical evaluation.

Twenty-six patients suspected of having acute myocardial infarction (AMI) underwent myocardial scintigraphy sequentially with 201Tl and 99mTc-stannous pyrophosphate (99mTc-PPi). Of the 26 patients, 24 had AMI documented by enzyme and electrocardiographic changes. Nineteen had transmural and five had subendocardial myocardial infarctions. The remaining two patients had "unstable angina pectoris." The mean time from onset to imaging was 4 days. Of the 24 patients with AMI, 22 had positive 99mTc-PPi scintigrams. In 20 the area of acute myocardial damage appeared to be the same by 99mTc-PPi scintigram as by ECG; in two, the location could not be precisely determined. The two patients with negative 99mTc-PPi scintigrams at the time of combined myocardial imaging had had positive 99mTc-PPi images previously. In all 24 patients, the 201Tl images were abnormal in at least the location suggested by the electrocardiogram. In seven patients, the area of decreased 201Tl activity was grossly equal to the positive area on the 99mTc-PPi images; in 15, the 201Tl defect was definitely larger; and in two, the 201Tl defect appeared slightly smaller. Although the 99mTc-PPi and 201Tl myocardial images provide different information, both are valuable in determining the overall integrity of the myocardium in patients with ischemic heart disease.     

Cardiac tomography with 99mTc-tetrofosmin after nitrate administration in patients with ischemic cardiopathy and left ventricular dysfunction

PURPOSE: To investigate the role of technetium-99m (99mTc) tetrofosmin single-photon emission Computed Tomography (SPECT) associated with nitrate administration in the detection of hypoperfused but still viable myocardium in patients with chronic coronary artery disease and left ventricular (LV) dysfunction. MATERIAL AND METHODS: Twenty-two patients (mean age 54 +/- 11 years) with coronary artery disease, previous myocardial infarction and LV dysfunction (LV ejection fraction 38 +/- 13%) were examined. On different days all patients underwent 99mTc tetrofosmin (740 MBq) SPECT under control conditions at rest and after sublingual nitroglycerin administration (10 mg). Regional tetrofosmin activity was quantitatively measured in 22 myocardial segments per patient. In each segment, tracer uptake was expressed as a percentage of the region with the peak activity. RESULTS: Under control conditions, 267 myocardial segments (55%) showed normal tetrofosmin uptake (> 70% of peak activity), 107 segments (22%) showed a moderate reduction (51-70%) and 110 segments (23%) a severe reduction (< or = 50%) in tracer uptake. Among the 110 segments with a severe reduction in tetrofosmin uptake, 20 (18%) showed increased tracer uptake > or = 10% of after nitrate administration (from 44 +/- 5% to 58 +/- 3%, p < 0.0001). The remaining 90 (82%) segments with a severe reduction in tetrofosmin uptake did not show any change after nitroglycerin administration (from 38 +/- 9% to 39 +/- 8%, p = ns). CONCLUSIONS: In patients with chronic coronary artery disease and LV dysfunction, tetrofosmin cardiac SPECT associated with sublingual nitrate administration allows the detection of severely hypoperfused but still viable myocardium.     

Dynamic and static 99mTc-ECD SPECT imaging of subacute cerebral infarction: comparison with 133Xe SPECT.

99mTc-ethylcysteinate dimer (99mTc-ECD) SPECT imaging reportedly fails to show reflow hyperemia in patients with subacute stroke. This study attempts to determine the clinical usefulness of dynamic 99mTc-ECD SPECT in evaluating regional blood flow in subacute cerebral infarction and the kinetic behavior of 99mTc-ECD in infarct areas. METHODS: 133Xe and consecutive dynamic and static 99mTc-ECD SPECT studies were performed on 24 patients with cortical infarction in the middle cerebral artery territory 13-15 d after the onset of a stroke. Image contrast between infarct and contralateral control areas on 99mTc-ECD tomograms (ECD uptake ratio) was compared with that on cerebral blood flow (CBF) images obtained using 133Xe inhalation (CBF ratio). RESULTS: In all cases, ECD uptake ratios from static images were lower than CBF ratios. This tendency was obvious when CBF in the infarct area increased above the normal control value, and no significant correlation was found between ECD uptake ratios from static images and CBF ratios. Only in the infarct areas with CBF below the normal control value, however, was a significant correlation between the two maintained (r = 0.795; P = 0.0011). A very strong correlation was found between CBF ratios and ECD uptake ratios on both the first dynamic scan (36 s after injection) (r = 0.991; P < 0.0001) and the second dynamic scan (72 s after injection) (r = 0.945; P < 0.0001). The correlation coefficient decreased in a time-dependent manner, with no significant correlation observed after the fourth dynamic scan (144 s after injection). On the other hand, significant correlations were observed on all dynamic scans only in the infarct areas with CBF below the control value. CONCLUSION: Super-early images of dynamic 99mTc-ECD SPECT provide a close imaging contrast with CBF and reveal reflow hyperemia in areas with irreversible changes produced by subacute stroke, which static 99mTc-ECD SPECT images fail to show. Decreased retention of the tracer in the infarct areas with hyperperfusion causes an underestimation of CBF on static 99mTc-ECD SPECT images. Given these results, we believe that dynamic 99mTc-ECD SPECT is an effective clinical tool to evaluate regional blood flow in subacute cerebral infarction.     

Assessment of myocardial infarctions using multidetector-row computed tomography

OBJECTIVE: To evaluate the diagnostic power of contrast-enhanced multidetector-row computed tomography (MDCT) in assessing the presence, age, and size of myocardial infarctions. METHODS: One hundred six patients underwent standard MDCT coronary angiography without additional changes in the protocol. In all patients, a complete patient history and left heart catheterization with biplane contrast ventriculography were available. The MDCT images were reviewed for the presence and age of myocardial infarctions in a blinded fashion. Infarct areas were detected as regions of reduced uptake of contrast in the early arterial phase and/or regional wall thinning. Reviewing the computed tomography (CT) images, CT density values (Hounsfield units [HU]) were measured at the site of infarcted and noninfarcted myocardium, and a volumetric assessment of the infarct size was performed. RESULTS: In 27 of 106 patients, myocardial infarctions were present. Multidetector-row computed tomography detected 23 of 27 infarctions (sensitivity of 85%, specificity of 91%, and accuracy of 90%). Comparing the HU of infarcted versus noninfarcted myocardium, the mean HU of infarcted areas was 54 +/- 19 HU versus 117 +/- 28 HU for noninfarcted myocardium (P < 0.01). Multidetector-row computed tomography was able to differentiate between recent and chronic infarctions. The infarct volumes of recent infarctions (6.3 +/- 3.6 cm) showed a negative correlation to the ejection fraction (EF) according to contrast ventriculography (ie, the larger the infarct volumes as measured using MDCT, the worse was the EF [r = -0.72, P < 0.01]). CONCLUSIONS: Performing standard MDCT coronary angiography, areas of infarcted myocardium can be identified with moderate to high sensitivity, without additional scanning or contrast administration. Infarct localization can be assessed accurately as compared with cineventriculography. To some degree, infarct age and infarct volume can be estimated.     

Prognostic implications of creatine phosphokinase levels after acute myocardial infarction--a study of low risk patients

To determine the prognostic value of Creatine Phosphokinase (CPK) levels after acute myocardial infarction in patients thought to be at low risk of death or major complications, 94 consecutive patients with definite myocardial infarction were divided into two groups according to peak CPK levels. Group I contained 23 patients with a peak CPK of less than 1000 units and Group II contained 71 patients with a peak CPK level of greater than 1000. They were followed for six months or to death. A CPK of greater than 1000 was significantly associated with left ventricular failure, major arrhythmias and late death and seemed therefore to have value as an indicator of poor prognosis.     

Clinical significance of augmented fluorine-18 deoxyglucose uptake in remote normoperfused myocardium in patients with acute coronary syndrome under fasting conditions

OBJECTIVES: We evaluated the relation between increased fluorine-18 deoxyglucose (FDG) uptake in remote normoperfused areas and acute ischemic events in patients with ischemic heart disease. METHODS: We performed nitrogen 13 ammonia (NH3) and FDG positron emission tomography (PET) on 67 patients (46 men, mean age 65 years) with ischemic heart disease (46 with myocardial infarction, 21 with angina pectoris). PET images were analyzed in only remote normoperfused areas (excluding infarct-related areas, areas containing coronary arteries with significant stenosis and/or showing vasoconstriction, and areas showing abnormal left ventricular wall motion). RESULTS: Seventeen patients (group 1) exhibited increased FDG uptake, as defined by our institution's guidelines, in remote normoperfused areas and 50 (group 2) did not. The plasma glucose levels (90.8+/-10.9 mg/dL vs. 94.9+/-11.8 mg/dL) and the serum insulin levels (7.3+/-2.9 IU/L vs. 8.6+/-3.4 IU/L) did not vary between the 2 groups. The serum free fatty acid levels were lower in group 1 than in group 2 (0.46+/-0.21 mEq/L vs. 0.62+/-0.29 mEq/L; P = .02). Patients were subsequently reclassified into either the acute coronary syndrome (ACS) group (n = 16), which consisted of patients exhibiting subacute myocardial infarction and unstable angina, or the non-ACS group (n = 51). A total of 11 (69%) of 16 ACS group patients but only 6 (12%) of 51 non-ACS group patients were included in group 1 (P<.0001). The serum free fatty acid levels were not different between ACS group and non-ACS group (0.52+/-0.21 mEq/L vs. 0.60+/-0.29 mEq/L; P = .17). CONCLUSIONS: Our data suggest that increased FDG uptake in remote normoperfused areas is closely related to the acute myocardial ischemia, suggesting that myocardial ischemic events may produce acceleration in glucose utilization even in remote nonischemic myocardium.     

Incidence, severity and clinical course of right ventricular involvement after acute inferior myocardial infarction; assessment by sequential 99Tcm-pyrophosphate scan and gated blood pool scan

To evaluate the incidence, severity and clinical course of right ventricular (RV) involvement after acute inferior myocardial infarction (IMI), 78 patients (pts) with IMI were investigated by both 99Tcm-pyrophosphate (PYP) scan and gated blood pool scan (GBPS). GBPS was performed at admission and 10 days, whereas 99Tcm-PYP scan was performed at 3 to 6 days. RV uptake of PYP was demonstrated in 25 (32%) pts on 99Tcm-PYP scan and RV akinesis or moderate hypokinesis by GBPS was observed in 39 (50%) pts on the acute scan; 25 pts (Group A) with positive RV uptake and 14 pts (Group B) with no RV uptake. In the remaining 39 pts (Group C) had normal RV wall motion. Severely depressed RVEF improved nearly 10 points on the tenth day in Group A (from 30.8 +/- 12.3 to 40.9 +/- 6.7%, p less than 0.01) and Group B (from 35.6 +/- 8.2 to 44.5 +/- 10.5%, p less than 0.01), respectively. Group C showed normal RVEF (from 47.4 +/- 7.6 to 50.1 +/- 10.2%). Fourteen pts of 39 (Groups A and B) who had developed shock or hypotension improved strikingly after appropriate therapy except for one death during their hospital course. Our data demonstrated: some patients with RV dysfunction in IMI do not have severe necrosis as judged by PYP scanning, those with positive RV uptake and depressed RV function show a lower degree of recovery than those with no RV uptake, but start from a lower initial value of RV function, and the combination of 99Tcm-PYP scan and GBPS offers prognostic information in IMI with RV dysfunction.     

Evaluation of myocardial function with the 201thallium scintimetry in various diseases of the heart. A correlative study based on 100 patients.

To assess the validity of the quantitative 201Tl scintimetry in various diseases of the heart (coronary heart disease with and without myocardial infarction, non-coronary cardiomyopathy, scleroderma heart disease and asymmetric septal hypertrophy with IHSS), the 201Tl myocardial uptake values for five standardized projections (a) were correlated with the grade of LAD stenosis, (b) the pattern of myocardial wall motion and (c) were compared with the 201Tl uptake values derived from normal patients. Significant reduction (c) of 201Tl myocardial uptake could in individual cases be evaluated in acute myocardial infarction (95%), in dys- and akinesia (90%), in hypokinesia (71%), in scleroderma heart disease (50%), in non-coronary cardiomyopathy (50%) as well as in normokinesia (28%) when associated with LAD stenosis. The mean values (b) of 201Tl uptake in normo- and hypokinesia significantly differed between these two groups and from those evaluated in dys- and akinesia. The latter group showed the lowest 201Tl uptake values computed which in some cases were very close to the mean mediastinal 201Tl uptake. The correlation (a) of individual 201Tl values demonstrated that 201Tl distribution in the myocardium is not only equivalent to myocardial "perfusion' but is corresponding with the myocardial function. In non-coronary cardiomyopathy reduced 201Tl values sometimes could not be separated from values in coronary heart disease (and myocardial infarction). A regional increase of myocardial mass as in septal hypertrophy correlated well with an augmented 201Tl uptake when referred to the 201Tl storage in the mediastinum.     

Evaluation of radiopharmaceuticals for the detection of acute myocardial infarction in man.

The accuracy of the scintigraphic diagnosis of acute myocardial infarction with 99mTc-pyrophosphate, 99mTc-tetracycline and 99mTc-glucoheptonate was assessed in 63 patients, 43 of whom had clinical evidence of acute myocardial infarction. In 15, studies with both 99mTc-tetracycline and 99mTc-pyrophosphate were performed. Accuracy was greatest with 99mTc-pyrophosphate (17/17 true positives, 8/10 true negatives) contrasted with 99mTc-tetracycline (12/25 true positives, 6/11 true negatives) and 99mTc-glucoheptonate (3/13 true positives, 2/2 true negatives). 99mTc-pyrophosphate was the most sensitive tracer for the detection of acute myocardial infarction. The diagnostic accuracy with 99mTc-glucoheptonate was poor.     

Technetium-99m pyrophosphate tomogram of nontransmural myocardial infarction: a case report

Single-photon emission computed tomography (SPECT) with 99mTc-pyrophosphate (99mTc-PYP) has been reported to be useful in the detection and localization of acute nontransmural infarctions. Localized uptake of 99mTc-PYP has been shown in patients with nontransmural infarction in these studies. It is likely, however, that anatomically transmural infarctions could be mislabelled as nontransmural infarctions, since the absence of new abnormal Q waves has been used in differentiating between nontransmural and transmural infarctions. We report a case of relatively diffuse nontransmural infarction demonstrated by a semicircle of 99mTc-PYP activity which significantly overlapped 201Tl uptake on the SPECT study.     

99mTc-MIBI scintigraphy of parathyroid adenomas and its relation to tumour size and oxyphil cell abundance

The aim of this study was to assess the correlation between technetium-99m methoxyisobutylisonitrile (MIBI) uptake by parathyroid adenomas, oxyphil cell content and volume of the lesions. Thirty-one patients with parathyroid adenomas were evaluated prospectively. Preoperative double-phase 99mTc-MIBI scintigraphy was performed in all patients and tracer uptake by parathyroid lesions was assessed semi-quantitatively employing region of interest ratios to normal adjacent neck areas. Surgical specimens underwent histological evaluation and oxyphil cell content was determined. The intensity of tracer uptake was compared with oxyphil cell content, volume of the lesions and serum levels of calcium and parathormone. 99mTc-MIBI tracer uptake was correlated with oxyphil cell content, volume of parathyroid lesions and the functional status of the parathyroid adenomas. Tracer accumulation in oxyphil cells might partially explain the preferential 99mTc-MIBI retention in parathyroid lesions.     

Prognostic value of impaired myocardial fatty acid uptake in patients with acute myocardial infarction

Impaired cardiac fatty acid uptake, assessed by the radiolabelled fatty acid analogue beta-methyl-p-iodophenyl pentadecanoic acid (I-123-BMIPP), is observed in the myocardium following acute ischaemic events, but the long-term prognostic implication has not been established. This study aimed to determine the prognostic value of cardiac BMIPP uptake in patients with acute myocardial infarction. Following the assessment of thallium-201 and I-123-BMIPP uptake, 101 post-infarct patients were prospectively followed up with primary end points of cardiac death, heart failure and non-fatal infarction. During a mean follow-up of 28 months, three cardiac deaths, three non-fatal infarctions, 23 revascularizations and four recurrences of angina pectoris were observed. Multivariate analysis identified reduced uptake of BMIPP and perfusion, no beta-blocking treatment and greater thallium-BMIPP mismatch (i.e. larger BMIPP defect than thallium defect) as significant predictors for overall cardiac events. Prior myocardial infarction, reduced left ventricular ejection fraction and greater thallium-BMIPP mismatch were selected as independent predictors of harder cardiac events. Female patients, those with greater BMIPP defect or greater thallium-BMIPP mismatch showed worse clinical outcomes. The inclusion of BMIPP data improved the prognostic values of conventional significant predictors. In conclusion, impaired myocardial I-123-BMIPP uptake and perfusion-BMIPP mismatch are related to a high probability of fatal and non-fatal cardiac events, suggesting the aetiological relevance and prognostic value of impaired cardiac fatty acid metabolism in viable, but jeopardized, myocardium following acute myocardial infarction.