Influence of age on serial change in TL/BMIPP dual isotope SPECT images after direct PTCA in patients with acute myocardial infarction

The purpose of this study was to investigate the influence of age on serial change in 201TlCl (TL) and 123I-BMIPP (BMIPP) dual isotope single photon emission computed tomography (SPECT) images after direct PTCA in patients (pts) with acute myocardial infarction (MI). Dual SPECT with TL and BMIPP at rest, radionuclide ventriculography for left ventricular ejection fraction (LVEF), and two-dimensional echocardiography for wall motion analysis were performed in 26 pts at the subacute and chronic phases after direct PTCA for acute MI. A defect score (DS) for SPECT images was interpreted as normal: 0, mildly decreased: 1, moderately or severely decreased: 2, complete defect: 3. The difference in DS between TL and BMIPP was defined as the mismatch score (MS). DS in BMIPP was greater than that in TL at the subacute phase in all pts. Significant improvement in the wall motion score was recognized in pts who showed TL/BMIPP discrepancy at the subacute phase. Pts were classified by age into two groups; group I: younger than 65 years old (n = 18); group II: 65 years and older (n = 8). Improvement of MS from the subacute to chronic phase was significant in group I (5.2 +/- 1.9 to 3.2 +/- 1.9, p = 0.0001), whereas not significant in group II (6.2 +/- 2.9 to 6.1 +/- 2.9, NS). There was a significant negative correlation between relative MS (ratio of subacute MS to chronic MS) and age (r = -0.78, p < 0.0001). No significant correlation was observed between age and improvement in LVEF. These results indicate that disordered myocardial fatty acid metabolism, reflected by TL/BMIPP discrepancy, persist longer in elderly pts than younger pts after acute MI.     

Myocardial imaging in acute myocardial infarction using beta-methyl-p-(123I)-iodophenylpentadecanoic acid: comparison with 201Tl imaging and wall motion]

Myocardial imaging using beta-methyl-p-(123I)-iodophenylpentadecanoic acid (BMIPP) was performed in 11 patients with acute myocardial infarction. The left ventricular images were divided into 12 segments, and myocardial imagings with BMIPP were compared with coronary angiography (CAG), thallium-201 myocardial scintigraphy (TL) and wall motion obtained by two-dimensional echocardiography (WM). When the culprit lesion was at the proximal point of the left anterior descending artery (LAD), all segments showed depressed uptake. In 3 cases with single vessel disease of the LAD, inferior wall of the basis showed reduced uptake of BMIPP despite the location of the culprit lesion. In cases with discordant uptake between the two tracers, BMIPP frequently showed more severely depressed uptake than TL in the subacute phase, although the uptake of BMIPP correlated with that of TL (tau = 0.82, p less than 0.001). In such cases, the discordance was related to the improvement in WM from the acute phase to the convalescent phase. BMIPP uptake correlated with WM in the subacute phase (tau = 0.50, p less than 0.001). BMIPP showed more severely depressed uptake while WM showed mild asynergy in most cases in which discordance was found between the BMIPP and WM findings. However, there was no correlation between the change in WM from the acute to subacute phases, or the uptakes of BMIPP and TL alone. We concluded that the myocardial condition can be evaluated in detail in acute myocardial infarction by comparing the findings of BMIPP with those of TL and WM.     

Prediction of improvement of left ventricular wall motion in patients with myocardial infarction--by using 99mTc-tetrofosmin and 123I-BMIPP myocardial SPECT at subacute phase

The relationship between myocardial perfusion, fatty acid metabolism, and cardiac functional recovery were investigated by using single photon emission computed tomography (SPECT) with 99mTc-1,2-bis[bis(2-ethoxyethyl)phosphino]ethane (tetrofosmin: TF) and lodine-123-beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) in patients with myocardial infarction. We examined myocardial SPECT in 18 patients with acute myocardial infarction (AMI) underwent successful reperfusion therapy within 24 hours from onset. TF myocardial SPECT (early and delayed images) and BMIPP (early image) SPECT were performed 2 weeks after onset of AMI, and regional TF and BMIPP defect scores of the infarct area were scored visually by a 4-point system. There was a significant correlation between the defect score of the TF delayed image, BMIPP image and SD/chord (indicator of regional wall motion abnormalities on left ventriculograms) at subacute phase (TF: r = -0.592, p = 0.011, BMIPP: r = -0.643, p = 0.004). Good correlations were also found between the defect score of the TF delayed image, the BMIPP image and the SD/chord at chronic phase (TF: r = -0.491, p = 0.037, BMIPP: r = -0.599, p = 0.007). Furthermore, there was a significant correlation between the improvement of SD/chord (acute to chronic phase) and the degree of reverse redistribution score of TF (r = 0.735, p = 0.022), and discordance score between TF and BMIPP (r = 0.691, p = 0.037). In conclusion, resting BMIPP and TF myocardial SPECT performed in patients with subacute phase AMI were shown to be useful in predicting improvement of left ventricular function at chronic phase.     

Regional metabolic abnormality in relation to perfusion and wall motion in patients with myocardial infarction: assessment with emission tomography using an iodinated branched fatty acid analog.

The clinical usefulness of single-photon tomography using both a beta-methyl-branched fatty acid analog, 123I-15-(p-iodophenyl)-3-methyl pentadecanoic acid (BMIPP) and 201TI was assessed in 4 normal subjects and 28 patients with myocardial infarction. A homogeneous distribution of the tracer in the left ventricular myocardium was observed in each normal subject. BMIPP uptake was decreased compared to 201TI (discordant) in 17/28 patients (61%) and in 49/196 myocardial segments (25%). Such discordant BMIPP uptake was observed more often in areas of acute myocardial infarction (59% at less than or equal to 4 wk versus 31% at greater than 4 wk after onset) (p less than 0.01) and areas supplied with revascularized arteries (74% for revascularized versus 28% for nonrevascularized areas) (p less than 0.01). In addition, the discordant BMIPP uptake was seen more often in the segments exhibiting a wall motion score lower than the perfusion score (46%) in comparison to segments showing a similar decrease in both the wall motion and perfusion scores (12%) (p less than 0.01). Thus, BMIPP imaging may play a major role in increasing our understanding of the relationship between perfusion and wall motion, particularly in patients with acute myocardial infarction and those who received revascularization therapy.     

Dynamic changes in cardiac fatty acid metabolism in the stunned human myocardium

BACKGROUND: The chronological changes or mechanisms in cardiac fatty acid metabolism under clinical conditions of hypoxia and ischemia have not been fully elucidated. 123-15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) can be used with single photon emission computed tomography (SPECT) to evaluate myocardial fatty acid metabolism. We investigated chronological changes in energy metabolism in the stunned human myocardium by means of 123I-BMIPP myocardial SPECT. METHODS AND RESULTS: We conducted 123I-BMIPP myocardial SPECT in 10 patients with stunned myocardium during the acute, subacute and chronic phases after onset. The left ventricle was divided into 9 regions on SPECT, and the degree of abnormalities in each region was scored in four grades from normal (0) to defect (4). We also examined wash-out rates on BMIPP images. The scores on early BMIPP images in the acute, subacute and chronic phases were 5.6 +/- 1.8, 13.4 +/- 3.5 and 2.5 +/- 1.1, respectively, and the score was highest in the subacute phase (p < 0.001). Similarly, scores on the late images were 2.3 +/- 1.7, 18.3 +/- 4.5 and 4.7 +/- 2.6, respectively, and highest in the subacute phase (p < 0.001). The wash-out rates (normal: 18.2 +/- 2.1%) in the acute, subacute and chronic phases were 12.1 +/- 4.8%, 44.9 +/- 10.0% and 23.1 +/- 4.6%, respectively, with the value being lowest during the acute phase (p < 0.05), and highest during the subacute phase (p < 0.001). CONCLUSION: These results suggested that fatty acid metabolism in the stunned human myocardium changes dynamically over time.     

Value of fatty acid imaging using 123I-beta-methyl iodophenyl pentadecanoic acid (BMIPP) to assess viability of infarcted myocardium]

To evaluate clinical value of a new fatty acid imaging tracer, 123I-beta-methyl iodophenyl pentadecanoic acid (BMIPP), 27 patients with myocardial infarction (MI) underwent BMIPP imaging at rest. The results were compared with those of thallium-201 imaging and contrast ventriculography. Of 100 hypoperfused segments on thallium-201 imaging, 34 segments (34%) showed lower BMIPP uptake than thallium-201, and remaining 66 segments showed similar distribution of those tracers. This discrepancy was more often observed in a patients with acute or subacute stages of MI (less than 4 weeks from onset) than those with chronic stage of MI (greater than 4 weeks) (75% vs. 47%; p less than 0.005). In addition, in the patients with chronic stage of MI, the regional wall motion abnormality was less severe in those showing discrepant BMIPP uptake than those showing concordant distribution (the wall motion score: 1.33 +/- 0.62 vs. 0.63 +/- 0.99; p less than 0.05). Furthermore, redistribution on stress thallium-201 imaging was more often observed in than those showing concordant distribution (12%) than those showing concordant distribution (12%) (p less than 0.005). These preliminary study indicates that discrepant distribution of BMIPP and thallium-201 may be often observed, particularly in recent MI and those showing less wall motion abnormality and redistribution on stress thallium-201 imaging. Thus, the combined study of BMIPP and thallium-201 has a potential for assessing tissue viability in patients with MI.     

The usefulness of 123I-BMIPP myocardial SPECT in diagnosis for silent myocardial ischemia induced by vasospasm

This study was designed to evaluate the clinical usefulness of 123I-BMIPP myocardial SPECT in patients with silent myocardial ischemia induced by vasospasm. Ultrasonic echocardiography (UCG), Holter electrocardiogram recording (Holter ECG), exercise 201Tl myocardial SPECT (EX-Tl) and rest 123I-BMIPP myocardial SPECT (BMIPP) were performed in 8 patients with asymptomatic vasospasm without history of myocardial infarction. The sensitivity of each modality in detecting coronary artery spasm was 37.5% (3 of 8 cases) for UCG, 37.5% (3 of 8 cases) in Holter ECG, 25.0% (2 of 8 cases) in Ex-Tl, 62.5% (5 of 8 cases) on initial BMIPP images and 75.0% (6 of 8 cases) on delayed BMIPP images. Severity of regional left ventricular wall motion abnormality in UCG correlated with the severity of regionally decreased tracer uptake in BMIPP. The washout rate of BMIPP was 18.7 +/- 2.4 in normal controls, 32.4 +/- 5.9 in asymptomatic vasospasm, and 38.2 +/- 4.0 in asymptomatic vasospasm with abnormal left ventricular wall motion. It was suggested that 123I-BMIPP myocardial SPECT might be useful for assessing asymptomatic vasospasm.     

Recovery of impaired left ventricular function in patients with acute myocardial infarction is predicted by the discordance in defect size on123I-BMIPP and201TI SPET images

A discrepancy between myocardial perfusion defect and wall motion abnormalities is frequently found early after coronary reperfusion in patients with acute myocardial infarction. The purpose of this study was to assess recovery of impaired left ventricular function by reference to the discordance in defect size between myocardial fatty acid uptake and myocardial perfusion using combined single-photon emission tomographic (SPET) imaging early after coronary perfusion therapy. In 37 patients with acute myocardial infarction, iodine-123 15(p-iodophenyl)-3(R, S)-methylpentadecanoic acid (BMIPP) and thallium-201 SPET scans were performed early after coronary reperfusion. A severity score was determined from the extent of the imaging defect with each tracer. Left ventricular wall motion score (WMS) and ejection fraction (EF) were obtained at admission and at 4 weeks after the onset of infarction. In 32 of the 37 patients, discordance in defect sizes delineated with the two SPET studies was found during the acute stage. The severity score for BMIPP was larger than that for²⁰¹Tl during the acute stage (7.7±2.4 vs 4.4±2.5,P <0.001). There was a fair correlation between the severity score for BMIPP and WMS (r=0.82,P <0.0001), but a poor correlation between that for²⁰¹Tl and WMS. The extent of discordance in severity scores between BMIPP and²⁰¹Tl during the acute stage correlated well with the extent of the improvement in WMS (r=0.86,P <0.0001) and that of EF (r=0.85,P <0.0001). We conclude that the discordance in defect size on BMIPP and²⁰¹TI SPET images during the acute stage of infarction is an early predictor of the viability of the myocardium at risk of infarction.     

Clinical evaluation of 99mTc-hexakis 2-methoxy isobutyl isonitrile (MIBI): multicenter phase III clinical trial]

Multicenter Phase III clinical trial on a new myocardial imaging agent, 99mTc-hexakis 2-methoxy isobutyl isonitrile (99mTc-MIBI), was carried out in 464 patients with various cardiac disorders. Both planar and tomographic images provided high-quality regional myocardial perfusion images which correlated well with 201TlCl images. The positive ratios of myocardial infarction and angina pectoris by the agent were as high as that of 201TlCl. In addition, ventricular function and wall motion could be assessed with first-pass and ECG gated studies. There was no serious adverse reaction which were attributed to 99mTc-MIBI in any of patients studied. A transient metallic taste was observed immediately after the injection in approximately 64% of the patients. Based on its safety and efficacy, the clinical usefulness of 99mTc-MIBI was observed in 562 (93.1%) of 604 injections. In conclusion, 99mTc-MIBI was useful as a imaging agent of myocardial blood flow.     

Serial changes in BMIPP uptake in relation to thallium uptake in the rat myocardium after ischaemia

Several clinical studies have shown that iodine-123 labelled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) uptake is often lower than the uptake of perfusion tracers in patients with ischaemic heart disease. However, BMIPP accumulation may not decrease during the acute phase of a stunned myocardium in patients with acute coronary syndrome. We evaluated serial changes in BMIPP and perfusion tracer uptake in the myocardium after ischaemia. We performed a 20-min left coronary artery occlusion followed by reperfusion in male Wister rats. One hour after the reperfusion, echocardiography was performed. Intravenous injection of iodine-125 labelled BMIPP and thallium-201 was performed 1 day (acute group) and 5 days (subacute group) after the operation. To determine the myocardial distribution of ¹²⁵I-BMIPP and ²⁰¹Tl, dual-tracer autoradiography was conducted. We identified regions of interest in the anterolateral wall as an area at risk and in the inferoseptum as a remote control area. The anterolateral wall/inferoseptum ratio (A/I ratio) was calculated to compare the distributions of ¹²⁵I-BMIPP and ²⁰¹Tl. Coronary occlusion induced hypokinesia in the anterolateral region 1 h after the reperfusion. The A/I ratio of ¹²⁵I-BMIPP was significantly higher than that of ²⁰¹Tl in the acute group (1.01±0.15 vs 0.80±0.23, P<0.001). On the other hand, there was no significant difference between the A/I ratios of ¹²⁵I-BMIPP and ²⁰¹Tl in the subacute group (0.88±0.18 vs 0.85±0.18). Two rats showed a significantly lower A/I ratio of ¹²⁵I-BMIPP than ²⁰¹Tl in the subacute phase. These data suggest that BMIPP uptake is preserved despite a decrease in perfusion in the acute phase after ischaemia. In the subacute phase, on the other hand, BMIPP uptake is similar to or even lower than thallium uptake. Since BMIPP uptake may change with time after ischaemia, careful interpretation of BMIPP uptake after ischaemia is required in a clinical setting.     

Clinical usefulness of iodine 123-labeled fatty acid imaging in patients with acute myocardial infarction

Background  Iodine 123-labeled 15-(p-iodophenyl)-3R,S-methylpentadecanoic acid (BMIPP) has recently been developed, since normal myocardium metabolizes free fatty acids. This study investigated the clinical usefulness of BMIPP imaging in patients with acute myocardial infarction (MI), particularly in the detection of stunned myocardium in patients who underwent acute coronary revascularization. Methods  The subjects were 41 patients with acute MI who had undergone emergency coronary revascularization. Both BMIPP and thallium-201 images at rest were obtained during the subacute phase. The myocardial distribution of radiotracers was quantified by generating circumferential count-distribution profile analysis. Initial 201 Tl imaging, delayed 201Tl imaging, and BMIPP imaging were performed, and the mean count densities in the infarct region (initial 201Tl images [TL1], delayed 201Tl images [TL2], and BMIPP images in the infarct region [BM], respectively) were obtained. The differences between mean count densities (TL1-BM: BM subtracted from TL1; TL2-BM: BM subtracted from TL2) were also calculated. Results  BM showed a higher correlation with wall motion data by echocardiography (WM) in the acute phase than other nuclear imaging tests, whereas TL2 showed the highest correlation with WM in the chronic phase. Acute to chronic WM improvement showed a good correlation with TL2-BM. Conclusion  Single photon emission computed tomography imaging with BMIPP is a candidate for providing the “memory image” of ischemic damage, whereas TL2 reflects all viable tissue. The mismatch between the tracers can serve as an indicator of myocardial stunning.     

Simultaneous assessment of Tc-99m-sestamibi and I-123-BMIPP myocardial distribution in patients with myocardial infarction: Evaluation of left ventricular function with ECG-gated myocardial SPECT

123I-labeled 15-(p-iodophenyl)-3R,S-methyl pentadecanoic acid (BMIPP) is a branched-chain free fatty acid that is used to evaluate various cardiac diseases. The aim of the present study was to investigate the relationship between myocardial perfusion (99mTc-sestamibi) and BMIPP uptake, and to correlate perfusion and metabolic alterations with regional left ventricular dysfunction in patients with myocardial infarction (MI). ECG-gated dual-isotope myocardial SPECT was performed on 130 patients with MI with sestamibi (555 MBq) and BMIPP (148 MBq). The patients were classified into 3 groups according to PTCA therapy and the interval between the onset of infarction and RI injection (OR time). Group A (n = 56) included patients whose OR time was less than one month and who had undergone successful PTCA, Group B (n = 36) had OR times of less than one month and had conservative medical therapy, and Group C (n = 38) had OR times of over one month. The severity scores of the dual-isotope images were calculated from the defect scores in 9 segments. From the ECG-gated SPECT data with sestamibi, the left ventricular ejection fraction (LVEF; %) and regional wall motion were determined automatically using the QGS program LVEF obtained from gated SPECT correlated well with the severity scores for sestamibi and BMIPP (r = -0.68 and -0.76, respectively). The delta severity scores (BMIPP scores - sestamibi scores) of Group A were significantly higher than those of the other two groups (3.6 +/- 3.0 vs. 1.5 +/- 1.7 and 1.0 +/- 1.4, p < 0.001 ). The rate of dysfunctional segments with normal sestamihi distribution was significantly higher in Group A than in Group C (20.7% vs. 6.7%, p < 0.001). ECG-gated dual-isotope SPECT is useful since myocardial perfusion, fatty acid metabolism and left ventricular function can be analyzed during a single examination, so that this procedure has the potential to provide comprehensive information when evaluating patients with ischemic heart disease.     

The clinical significance of reverse redistribution of Tl-201 SPECT at rest in the 1st month after the onset of acute myocardial infarction

The pattern of Thallium-201 reverse redistribution (r-RD) at rest has been reported in some patients with acute myocardial infarction (AMI) in the acute phase. But there is no report of this pattern in the later phase. To investigate the significance of Thallium-201 reverse redistribution in the subacute phase, 37 patients with AMI underwent Thallium-201 SPECT at rest a month after the onset. The patients were classified into three groups visually and 19 of 37 patients (51%) showed the persistent defect pattern (Group PD), and the remaining 18 patients (49%) had the reverse redistribution pattern (Group r-RD). None of them had the redistribution pattern. Coronary reflow was earlier and the incidence of the scintigraphic overlap on Dual SPECT image of 99mTc-PYP/201TlCl in the acute phase was more frequent in Group r-RD than in Group PD. A decrease in thallium defect size of patients with r-RD from the acute phase to one month after the onset represented improvement more significantly than that with PD. Initial %Tl uptake of the infarcted region of Group r-RD was greater than that of Group PD. The degree of stenosis of the infarct-related coronary artery in Group r-RD was less severe than that in Group PD. And corresponding regional wall motion of Group r-RD was less impaired. The Thallium-201 washout in the infarcted region with r-RD was significantly faster than that in the normal region. It is concluded that the r-RD pattern at rest in the 1st month after the onset of AMI may be a sign of viable myocardium.     

Changes in perfusion and fatty acid metabolism of rat heart with autoimmune myocarditis

To elucidate the change in perfusion and aerobic metabolism in myocarditis, tissue counting and dual tracer ex vivo autoradiography with Tl-201 and a free fatty acid analog, I-123- or I-125-labeled (p-iodophenyl)-methyl-pentadecanoic acid (BMIPP), were performed in rats with myocarditis induced by immunization with cardiac myosin. Inflammatory damage was classified histologically. At the acute stage (2-4 weeks after the antigen-injection), total heart uptakes of Tl and BMIPP and the ratio (BMIPP/Tl) were significantly reduced in myocarditis rats (N = 15) compared with the controls (N = 12). Myocardial distribution of Tl and BMIPP was not homogeneous. Relative uptake of Tl and BMIPP (N = 9, 128 regions) was gradually decreased with the extent of inflammation, and the regional BMIPP/Tl was smaller than the control. At the subacute stage (7 weeks after the antigen-injection), total Tl uptake in myocarditis rats (N = 5) recovered to the control level (N = 4), but that of BMIPP was still significantly lower than the control. BMIPP/Tl was still significantly lower in myocarditis. Myocardial distribution of Tl and BMIPP recovered to be more homogeneous. Relative uptake of Tl and BMIPP (N = 6, 78 regions) still gradually but significantly decreased with the extent of inflammation. Regional BMIPP/Tl was still depressed in myocarditis. These results indicate that myocardial perfusion and aerobic metabolism were discrepant and heterogeneously suppressed with severe inflammation during the acute stages, but the difference decreases with time. Examination with Tl-201 and BMIPP may provide information about the severity of myocarditis.     

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.     

Abnormal fatty acid metabolism in patients with coronary vasospasm

Although various noninvasive methods have been used to detect vasospasm, none of them are sensitive enough for patients with sporadic attacks. Since abnormal fatty acid metabolism is observed in ischemic myocardium, 123I-beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP), a radiolabeled fatty acid analog, has recently been proposed as a useful tracer for detecting myocardial damage. The aim of this study was to clarify the clinical implications of decreased myocardial BMIPP uptake in patients with vasospastic angina. We evaluated 53 patients with vasospastic angina (32 with clinically documented vasospasm [Group-A] and 21 with vasospasm induced by ergonovine provocation [Group-B]) and 27 control subjects, 20 in Group-A were re-evaluated 6 months after medical treatment. The territorial regions of vasospasm-induced coronary artery, the wall motion by left ventriculography, and BMIPP uptake were compared. Vasospasm was induced in multiple coronary arteries in 29 (55%) patients. Reduced wall motion and decreased BMIPP uptake were observed in 19 (36%) patients and 47 (89%) patients, respectively. The sensitivity and specificity of determination of vasospasm-induced coronary arteries with BMIPP scintigraphy were 71% (69/97 coronary arteries) and 88% (126/143), respectively. Vasospasm was re-induced by ergonovine provocation in 8 patients (Group-I) and not re-induced in 12 (Group-II) after treatment. In Group-I, improvement of decreased BMIPP uptake was lower than in Group-II (19+/-11 vs. 59+/-22%, mean+/-SD, p < 0.001). The regions in which vasospasm was re-provoked exhibited decreased BMIPP uptake. Abnormal fatty acid metabolism was more often observed than wall motion abnormality in the vasospastic region in patients with vasospastic angina. BMIPP scintigraphy is a highly accurate and non-invasive technique for determining the presence and location of vasospasm.     

Assessment of regional wall motion and perfusion by multigated myocardial scintigraphy after intracoronary Tl-201

Fourteen patients undergoing intracoronary thrombolysis for acute myocardial infarction had intracoronary injection of thallium-201 to assess myocardial salvage after reperfusion. Scintigrams of the perfused myocardium were gated and compared with both ungated scans and radionuclide ventriculograms (multigated blood pool scintigrams) to determine the value of gated perfusion images for studies of both perfusion and regional wall motion. Multigated and ungated thallium images provided comparable information about regional myocardial perfusion. Correlation between multigated thallium images of regional wall motion and radionuclide ventriculograms was poor (tau = 0.44). Assessment of wall motion was most accurate in well-perfused segments and least accurate in partially perfused segments.     

Impairment of regional fatty acid uptake in relation to wall motion and thallium-201 uptake in ischaemic but viable myocardium: Assessment with iodine-123-labelled beta-methyl-branched fatty acid

In coronary artery disease, discrepancy in the uptake of thallium-201 and of methyl-branched fatty acid at rest has been described. The purpose of this study was to evaluate iodine-123 labelled beta-methylbranched fatty acid (BMIPP) myocardial uptake and wall motion at rest in segments with stress-induced ischaemia identified by stress²⁰¹Tl tomography in patients with chronic coronary artery disease.¹²³I-BMIPP myocardial tomography was performed at rest and was compared with the findings of exercise-reinjection²⁰¹Tl tomography in 45 patients with chronic coronary artery disease. Regional wall motion was evaluated by contrast left ventriculography in 36 patients. Among 237 segments with reversible²⁰¹Tl defects, equally decreased uptake on both reinjection²⁰¹Tl and BMIPP images was observed in 93 (39%), more severely decreased uptake of BMIPP in 118 (50%) and more severely decreased uptake of reinjection²⁰¹Tl in 26 (11%). On the other hand, among 90 segments with non-reversible²⁰¹Tl defects, each pattern was observed in 71 (79%), 6 (7%) and 13 (14%) segments, respectively. When comparing the ischaemic segments with and without more severely reduced uptake of BMIPP than of reinjection²⁰¹Tl, wall motion was impaired to a greater extent in the segments with more severely reduced uptake of BMIPP than of reinjection²⁰¹Tl [severe hypo- or dyskinesis was present in 64 (70%) of 91 segments and in 24 (22%) of 110 segments, respectively,P<0.005]. In patients with chronic coronary artery disease, resting fatty acid uptake was frequently more reduced than reinjection²⁰¹Tl in the segments with stress-induced ischaemia, while in most of the fixed perfusion defects BMIPP and reinjection²⁰¹Tl uptake decreased concordantly. In ischaemic myocardium, wall motion was impaired to a greater extent in those segments which showed more severely reduced uptake of BMIPP than of reinjection²⁰¹Tl. In ischaemic but viable myocardium, discordant BMIPP uptake less than reinjection²⁰¹Tl uptake may indicate metabolic alterations and wall motion abnormality at rest independent of perfusion abnormalities. In conclusion, the combination of resting BMIPP and stress-reinjection²⁰¹Tl imaging may provide information on metabolic alterations and wall motion abnormality at rest independent of perfusion abnormalities.     

Effects of preinfarction angina on myocardial injury in patients with acute myocardial infarction: a study with resting 123I-BMIPP and 201T1 myocardial SPECT.

METHODS: Recent studies have suggested that patients with preinfarction angina have smaller infarcts and a better in-hospital outcome than those without angina. The mechanisms responsible for limitation of infarct size in the presence of preinfarction angina are unclear. We examined the effects of preinfarction angina on myocardial injury in patients with the first acute myocardial infarction with resting 123I-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) 201TI myocardial scanning performed within 1 mo of infarction. RESULTS: Of 136 patients tested, 48 (35%) had preinfarction angina within 72 h before infarction, whereas 88 (65%) did not. BMIPP and 201TI defects were scored in 9 segments of the left ventricle (0 = normal, 1 = mild defect, 2 = moderate defect, 3 = severe defect, and 4 = no uptake). The total defect score was defined as the sum of the defect scores. There was no significant difference in percentage diameters of stenoses of infarct-related arteries, collateral circulation, total defect scores for BMIPP, or 201TI between the groups with and without preinfarction angina. However, the ratio of total defect score for 201TI to that for BMIPP was significantly smaller for patients with than for those without preinfarction angina (0.64 +/- 0.21 versus 0.74 +/- 0.25, respectively; P = 0.007). CONCLUSION: Preinfarction angina did not affect the areas at risk in acute myocardial infarction, as shown by BMIPP defect, but decreased necrotic myocardium in the areas at risk, as shown by 201TI defect, and increased metabolically damaged but viable myocardium, as shown by BMIPP and 201TI mismatch through unidentified mechanisms other than collateral circulation (e.g., ischemic preconditioning).     

Time course of discordant BMIPP and thallium uptake after ischemia and reperfusion in a rat model.

Serial changes in fatty acid metabolism or use associated with acute ischemia and reperfusion were examined in rat hearts. METHODS: Male Wistar rats were subjected to occlusion of the left coronary artery for 20 min followed by reperfusion. After release of the occlusion, groups of animals were allowed to recover for intervals of 20 min (n = 9), 1 d (n = 9), 3 d (n = 6), 7 d (n = 6), or 30 d (n = 6). Hearts were excised 15-20 min after injection of 0.74 MBq of (125)I-15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) and 14.8 MBq of (201)Tl. One minute before resection, the left coronary artery was reoccluded and 185 MBq of (99m)Tc-sestamibi were injected to document the area at risk. Triple-tracer autoradiography was performed to assess tracer uptake. Uptake ratios of BMIPP and (201)Tl in the area at risk were calculated on the basis of the count density in the lesion divided by that in the normally perfused area. RESULTS: (201)Tl uptake did not change throughout the observation period (P = 0.25). In contrast, BMIPP uptake increased early in the acute phase (20 min and 1 d), decreased during the subacute phase (7 d), and subsequently recovered in the chronic phase (30 d). CONCLUSION: The present investigation clearly illustrated that BMIPP uptake is higher than (201)Tl uptake in the acute phase, that BMIPP uptake is lower than (201)Tl uptake in the subacute phase, and that BMIPP uptake and (201)Tl uptake are similar in the chronic phase. These results yield data essential to the precise interpretation of BMIPP images.