Quantitative evaluation of acute myocardial infarction by In-111 antimyosin Fab myocardial imaging]

For quantitative evaluation of acute myocardial infarction, In-111 antimyosin Fab myocardial imaging (InAM) was performed in 17 patients with myocardial infarction who underwent Tl-201 (TL) and Tc-99m pyrophosphate (PYP) myocardial imaging in acute phase. For calculating the infarct size, voxel counter method was used for analysis in PYP and InAM, and extent and severity score were used on bull's-eye polar map in TL. The most appropriate cut-off level ranged from 65 to 80% by the fundamental experiment using cardiac phantom. The cut-off level of 0.70 (InAM) and 0.65 (PYP) were used for clinical application of voxel counter analysis. The infarct size calculated by InAM and PYP was compared with wall motion abnormality index by echocardiography (WMAI), TL extent score, TL severity score, peak CK and sigma CK. Infarct size by InAM showed the following correlations with other indices. PYP: r = 0.26 (ns), TL extent score: r = 0.72 (p less than 0.01), TL severity score: r = 0.65 (p less than 0.05), WMAI: r = 0.69 (p less than 0.05). The infarct size by PYP did not show any correlations with these indices. Therefore, the infarct size by InAM showed better correlations with TL and WMAI than that of PYP. So InAM was considered superior to PYP for quantitative evaluation of acute myocardial infarction.     

Estimation of destruction of necrotic myocardium with serial PYP SPECT images and serum myosin light chain I level]

PYP SPECT images were underwent in 15 patients with acute myocardial infarction 2-5 times in three weeks. PYP SPECT images were reconstructed as to include both vertebral images and myocardial images. Quantitative estimation of PYP images was performed by the ratio of maximal PYP myocardial uptake to maximal PYP vertebral uptake in the central sagittal images (%PYP). Disappearance of PYP images was defined as the day, when %PYP reached 50%. Normalization of serum myosin light chain I (LCI) level was defined as the day, when LCI level reached 2.5 ng/ml. %PYP decreased continuously and maximal PYP point remained at the same area. Shape of PYP images varied and diminished. In case of anterior wall infarction apical PYP uptake persisted longer than basal uptake. In case of inferior wall infarction basal PYP uptake persisted longer than apical uptake. The mean period from onset to the disappearance of PYP images was 9 +/- 3 days. Pattern of serial serum MB level was simple, however corresponding pattern of serial serum LCI level showed various types. The mean period from onset to the peak level was 4.1 +/- 1 day. Normalization of LCI level was 9.3 +/- 2.9 days. It showed that process of destruction of necrotic myocardium vary in each case. Weak relation was noted between disappearance of PYP images (DAY-PYP) and normalization of LCI level (DAY-LCI). DAY-PYP = 4.4 +/- 0.46 DAY-LCI (n = 13, r = 0.4). Quantitative PYP images were useful for detecting ongoing necrotic myocardium and serum LCI level was useful for estimating destruction of necrotic myocardium.2+ level were useful to study the process of destruction of necrotic myocardium.     

Myocardial uptake of antimyosin antibody compared with serum myosin light chain I levels in patients with myocardial infarction

Myocardial accumulation of In-111-antimyosin (InAM) was evaluated in comparison with circulating serum myosin light chain I (LCI) level at the time of InAM injection. Seventeen consecutive patients were studied at various stages ranging from 6 days to 34 days after myocardial infarction (MI). The infarct area was positive for InAM uptake in all patients (100%), and significant myocardial uptake was observed in 14 patients (82.4%). The intensity of InAM uptake correlated with the infarct location shown by ECG and CAG. In contrast, 12 patients (70.6%) had normal or undetectable serum myosin LCI levels, with 5 being normal (0.42-2.5 ng/ml) and 7 undetectable (0.42 ng/ml or less). Only 5 patients (29.4%) had elevated serum myosin LCI levels at the time of InAM injection, and this elevation was slight, ranging from 3.4 to 4.5 ng/ml (mean: 3.75 ng/ml). Among patients with undetectable, normal, and elevated serum myosin LCI levels, there was no significant correlation between InAM uptake and the serum myosin LCI level. Thus, even after the serum myosin LCI level has decreased to normal, InAM can still bind to cardiac myosin in patients with MI, presumably until there is complete recovery from the hibernating myocardium due to ischemic damage.     

Clinical trial of 111In-antimyosin antibody imaging: (3) Comparison with 99mTc-pyrophosphate imaging

Clinical value of 111In-antimyosin monoclonal antibody F ab (AM) was compared with 99mTc-pyrophosphate (PYP) in 13 patients with myocardial infarction and 3 patients with myocarditis. Following PYP injection, PYP imaging was performed 3 hours later. Immediately after PYP imaging, AM was administrated and AM images were obtained 48 hours later. Abnormal accumulation in the infarcted myocardium was observed in 11 patients (85%) on AM images but only in 3 patients (23%) on PYP images. All patients within 8 days after the onset of infarction showed abnormal uptake on both images. Of 5 patients with 1 to 2 weeks after the onset of infarction, abnormal uptake was observed in all of them on AM images but only in one of them on PYP imaging. Furthermore, of 6 patients with more than 2 weeks after the onset, AM imaging showed abnormal uptake in 4 (67%) but PYP imaging did not show abnormal uptake in any of them. Similarly. Of 3 patients with myocarditis, diffuse uptake in the myocardium ws observed in 2 of them on AM images but none of them showed abnormal uptake on PYP images. We conclude that AM imaging is a useful means for identifying not only acute stages but also subacute stages of myocardial necrosis where PYP imaging did not show any abnormality.     

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.     

Diagnostic utility of myocardial imaging using 123I-labeled beta-methyl-iodophenyl pentadecanoic acid in ischemic heart disease]

We evaluated the myocardial metabolism in the acute and subacute phases of myocardial infarction or unstable angina using 123I-labeled beta-methyl-iodophenyl pentadecanoic acid (BMIPP). We then compared those findings with (1) myocardial perfusion images obtained with 201TlCl and (2) the regional and global left ventricular function determined by left ventriculography. Thirty-one patients were examined, consisting of 16 with acute myocardial infarction (6.8 +/- 2.6 days after onset), 8 with subacute myocardial infarction (35 +/- 3.0 days after onset) and 7 with unstable angina. The BMIPP images showed a larger uptake-defect than 201TlCl images in the patients in the acute or subacute phase of myocardial infarction. This finding was especially remarkable in the acute phase after successful coronary revascularization therapy. Moreover, in such cases, the myocardial BMIPP uptake improved to the same degree as 201TlCl one month later. The decrease in myocardial uptake of BMIPP agreed well with the decrease in regional wall motion in the acute and subacute phases of myocardial infarction. In contrast, the myocardial perfusion of 201TlCl did not always agree with the regional wall motion in stunned or hibernating myocardium, where BMIPP showed an uptake-defect in the acute phase but improved in the subacute phase. Thus, BMIPP is surmised to be able to depict fatty acid metabolism in in vivo myocardial imaging.     

Serial assessment of myocardial infarction by using gated MR imaging and Gd-DTPA

In order to assess the usefulness of Gd-DTPA in the evaluation of myocardial infarction, 17 patients were examined with gated MR imaging. Scans were made by using a spin-echo pulse sequence before and after IV administration of 0.15 mmol/kg of Gd-DTPA. The images were made at four intervals (average of 5, 12, 30, and 90 days) after the onset of the infarction. Gd-DTPA uptake at the infarcted area was graded as marked, moderate, or no increase in signal intensity by visual inspection. At these four time intervals, an area of increased signal intensity in the infarcted myocardium was detected on T1-weighted images after administration of Gd-DTPA in 14 (82%) of 17 cases, 16 (94%) of 17 cases, six (38%) of 16 cases, and three (21%) of 14 cases, respectively. Markedly increased signal intensity in infarcted areas was shown on T1-weighted images with Gd-DTPA at 5 and 12 days. The ratio of gadolinium uptake in the infarcted area to that in normal myocardium also was evaluated. At 5 and 12 days, the mean increase in signal intensity in the infarcted area was significantly higher than that in a normal area, but not at 30 and 90 days. Increased signal intensity also was apparent on T2-weighted images without Gd-DTPA at 5 and 12 days; however, the use of late echo reduced the signal-to-noise ratio, leading to image degradation. Uptake of Gd-DTPA was a positive marker in acute myocardial infarction, but no significant uptake of Gd-DTPA occurred in chronic myocardial infarction.     

Myocardial imaging. Coxsackie myocarditis

A 3-week-old male neonate with heart failure associated with Coxsackie virus infection was imaged with Tc-99m PYP and TI-201. The abnormal imaging pattern suggested myocardial infarction. Autopsy findings indicated that the cause was myocardial necrosis secondary to an acute inflammatory process. Causes of abnormal myocardial uptake of Tc-99m PYP in pediatrics include infarction, myocarditis, cardiomyopathy, bacterial endocarditis, and trauma. Myocardial imaging cannot provide a specific cause diagnosis. Causes of myocardial infarction in pediatrics are listed in Table 1.     

Diagnostic utility of 111In-antimyosin Fab scintigraphy in acute myocardial infarction: comparison with 201Tl and 99mTc-pyrophosphate myocardial scintigraphy]

To assess the diagnostic accuracy, extent, and characteristics of 111In-antimyosin Fab scintigraphy (In-AM) in acute myocardial infarction (AMI), we studied In-AM in 17 patients with AMI and compared with In-AM, 99mTc-PYP and 201Tl scintigraphy. Intensity of In-AM uptake was classified into 3 grades. Fourteen of 17 patients (82%) showed positive uptake of In-AM. The locations of infarct area diagnosed by In-AM were in accordance with those by electrocardiography. There was a good correlation between the extent score of In-AM planar and that of SPECT (r = 0.72), In-AM SPECT and Tl SPECT (r = 0.79), In-AM planar and PYP planar (r = 0.92), In-AM SPECT and PYP SPECT (r = 0.76), respectively (p less than 0.01). Thus, In-AM is a useful method for diagnosis of AMI.     

PET "reversed mismatch pattern" early after acute myocardial infarction: follow-up of flow, metabolism and function

The aim of this study was to evaluate changes of flow, metabolism and left ventricular function in patients revealing a "reversed mismatch" pattern (reduced glucose uptake relative to perfusion) on positron emission tomography (PET) early after myocardial infarction. In 19 out of 68 patients (28%), prospectively included in the GUSTO-I or STAR studies, a PET reversed mismatch pattern in the infarct-related region was found. All patients received thrombolytic therapy within 3 h after onset of pain and coronary angiography 90 min later. 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG)/nitrogen-13-labelled ammonia (13NH3) PET was performed after 5 days and 3 months. In 12 of the 19 patients, functional recovery was investigated with two-dimensional echocardiography at the same time points. In the infarct-related region, normalized 13NH3 uptake was 76% +/- 11% at 5 days and 85% +/- 10% at 3 months (P < 0.00001). Absolute blood flow in this region was 75 +/- 25 ml/min per 100 g at 5 days and 80 +/- 19 ml/min per 100 g at 3 months. At 5 days, normalized 18F-FDG uptake in the infarct-related region was decreased (51% +/- 12%). At 3 months, 18F-FDG uptake in this region had significantly recovered (75% +/- 11%, P < 0.00001). In the infarct-related region, absolute FDG metabolism was 17 +/- 6 mumol/min per 100 g at 5 days and 26 +/- 9 mumol/min per 100 g at 3 months (P < 0.0001). At 5 days, normalized 18F-FDG uptake was more severely decreased as compared to the normalized 13NH3 uptake (P < 0.00001) in the infarct-related region, resulting in a reversed mismatch pattern (25% +/- 13% of the left ventricle). At 3 months, 18F-FDG metabolism had partially recovered, giving rise to a change into a PET match pattern. Reversed mismatch regions were present in only 7% +/- 7% of the left ventricle at that time. The ratio of 18F-FDG uptake to 13NH3 uptake in the infarct-related region increased from 0.67 +/- 0.8 at 5 days to 0.88 +/- 0.09 at 3 months (P < 0.00001). No functional recovery was observed in the infarct-related region (the 5-day and 3-month wall motion scores were both 2.5 +/- 0.5). In patients with a myocardial infarction showing a PET reversed mismatch pattern 5 days after thrombolytic therapy, recovery of 18F-FDG uptake was found but no functional recovery was observed at 3-month follow-up.     

Indium-111-antimyosin antibody imaging for detecting different stages of myocardial infarction: comparison with technetium-99m-pyrophosphate imaging

The diagnostic value of 111In-antimyosin (AM) imaging for identifying myocardial infarction was evaluated in comparison with 99mTc-pyrophosphate (PPi) imaging. Twenty-four patients with various stages of myocardial infarction, ranging from three days to nine months after the onset of infarction, underwent both AM and PPi scans. Of 26 infarct lesions AM scan identified 22 (85%), while PPi scans detected 10 (38%) (p less than 0.01). When less than a week had passed since the onset both scans demonstrated all infarct lesions. For seven subacute lesions studied within one to two weeks of onset, AM scans detected (100%), while PPi scans identified only 2 (29%). Furthermore, AM scans showed discrete myocardial uptake in 7 (64%) of those studied more than two weeks after onset. The intensity of AM uptake in the infarcts studied more than seven days after onset was less than that in acute infarcts studied within seven days of onset (p less than 0.05). These preliminary data indicate that the abnormal myocardial uptake of AM persists beyond the first two weeks when PPi no longer accumulates. Thus, AM scans can be considered to provide a sensitive diagnosis of subacute as well as acute myocardial necrosis.     

Acute subendocardial infarction with diffuse intense Tc-99m PYP uptake and minimal Tl-201 abnormality.

Tc-99m PYP scintigraphy performed on a patient with severe anterior chest pain showed diffuse intense uptake with central decreased activity corresponding to the left ventricular cavity. Tl-201 myocardial perfusion scintigraphy at rest revealed a minimal perfusion abnormality with decreased apical uptake in the lateral view. Because of these findings, diffuse subendocardial infarction was suggested.     

Myocardial viability in QS region after PTCR

Myocardial viability after PTCR in patients with first anterior myocardial infarction was studied one month after the onset of acute myocardial infarction by profile curve of Tl-201 coronal myocardial SPECT images. Patients were devided into two groups according to left ventricular ejection fraction (EF), i.e. group A (EF more than 50%; 11 cases , EF; 62 +/- 10%) and group B (EF less than 50%; 9 cases, EF; 40 7%). Patients in group A showed an increase in serum GOT at the acute phase of acute myocardial infarction (322 +/- 182IU), decreased %Tl-201 uptake in QS region (65 +/- 7%) significantly less than the normal range, large size of region of infarction (214 +/- 83 degree) and abnormal QS in ECG (V1-3QS; 2 cases, V1-4QS; 8 cases, V1-5QS; 1 case). Improvement of wall motion in region of infarction was noted in 9 cases. Patients in group B showed an increase in serum GOT (651 +/- 382 IU p; ns), %Tl-201 uptake in QS region (48 +/- 7% p greater than 0.001) significantly less than the %Tl-201 uptake in group A, size of defects (243 +/- 45 p; ns) and abnormal QS in ECG (V1-3QS; 1 case, V1-4QS; 7 cases V1-5QS; 1 case). Improvement of wall motion was noted in 2 cases. The study showed that %Tl-201 uptake in region of infarction in patients with well EF was significantly more than that in patients with depressed EF. Mechanism of maintaining well EF after PTCR was suggested as the following, i.e. in the region released from severe ischemic attack part of myocardium resulted in necrosis, accompanying elevation of serum enzyme and appearance of QS, though part of myocardium might be salvaged from necrosis and contribute to EF in chronic phase. It has been generally thought that abnormal QS waves noted in anterior chest leads of ECG in chronic phase indicated transmural myocardial infarction in the anterior region. From this study it was concluded that QS region with %Tl-201 more than 50% did not generally correspond to transmural myocardial necrosis and that for estimation of myocardial viability %Tl-201 uptake might be more useful than ECG.     

The diagnostic value of Tc-99m PYP, Tl-201 dual isotope SPECT to predict the viability of damaged myocardium in the acute phase of myocardial infarction--comparison with stress, delayed, and reinjected Tl-201 SPECT]

To assess the diagnostic value of Tc-99m PYP, Tl-201 dual isotope SPECT for the evaluation of myocardial viability, segmental comparison between dual isotope SPECT and exercise, delayed, and reinjected Tl study were performed with 18 AMI patients. Among 72 damaged myocardial segments, 48 segments (67%) were judged as viable by chronic phase Tl studies. The segments with severely reduced Tl uptake by dual SPECT showed significantly lower prevalence of viable myocardium than the segments with reduced and normal Tl uptake (p less than 0.001). The segments with PYP accumulation localized to the subendocardium represented the favorable outcome compared with the transmural accumulation (p less than 0.001). And overlap segments show better prognosis than the segments without overlap (p less than 0.05). Most importantly, we can get better predictive accuracy of myocardial scar by dual isotope SPECT than the judgement by Tl or PYP SPECT alone (83.3% vs 77.8%, 68.1%). Thus, we conclude that Tc-99m PYP, Tl-201 dual isotope SPECT is useful to assess the severity of myocardial damage in the acute phase of myocardial infarction.     

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.     

Twenty-four-hour Tl-201 delayed scan underestimates myocardial viability in patients with acute myocardial infarction after percutaneous transluminal coronary angioplasty

BACKGROUND: Myocardial viability in area at risk of acute myocardial infarction (AMI) after reperfusion therapy may be underestimated by the 24-hour images due to reverse redistribution (r-RD). METHODS: Subjects were 37 AMI patients in whom Tc-99m pyrophosphate (PYP)/Tl-201 dual-isotope SPECT was positive. The 24-hour delayed scan was performed with only a Tl window. One month later, follow up rest Tl SPECT was performed to evaluate myocardial viability. In early (at PYP/Tl-201 dual-isotope SPECT), 24-hour, and one month follow up Tl studies, Tl uptake in the area of AMI was scored into four grades: 3 as normal to 0 as severely reduced. The scores were evaluated. RESULTS: Among the 37 AMI lesions, there were 16 r-RD, 3 RD, 16 fixed defect (FD) and 2 normal (positive PYP and normal Tl). Mean Tl scores were early; 1.4 +/- 1.1, 24-hr; 0.9 +/- 0.9 and one month; 1.3 +/- 1.1. The 24-hour Tl score was lower than the early and one month Tl scores (p < 0.01). CONCLUSION: Reverse redistribution is frequently observed in an area at risk where PYP SPECT was positive. Nuclear medicine physicians should be aware of the existence of frequent r-RD in Tl scan to avoid the underestimation of myocardial viability in the acute phase after PTCA.     

老年人急性心肌梗塞的冠脉造影特点与护理

目的:探讨老年人急性心肌梗塞(AMI)冠脉造影(CAG)的特点及发病机制和围造影期的并发症,以指导临床治疗与护理。方法:1998年12月~2003年2月间老年人AMI 564例,入选病例均为发病后12h内先给予溶栓和抗凝治疗,后行CAG。梗塞相关动脉(IRA)根据狭窄程度按Proudilit分级法。结果:CAG显示564例中病变血管狭窄<50%者74例(13.2%),次全梗阻和完全闭塞病变415例(73.7%);双支病变409例(72.5%);病变血管狭窄>75%者有394例(69.8%)454处病变即刻或择期行介入治疗,其成功率为100%。围造影期常见并发症为低血压、迷走反射、对比剂反应、室颤、动脉夹层等。结论:老年人急性心肌梗塞以多支病变为多,以严重狭窄和闭塞病变为主,发病机制主要为粥样斑块基础上的血栓形成;围造影期常见的并发症低血压、对比剂反应、迷走反射等早期发现、及时处理可迅速缓解。     

Acute myocardial infarction: myocardial viability assessment in patients early thereafter comparison of contrast-enhanced MR imaging with resting (201)Tl SPECT. Single photon emission computed tomography

PURPOSE: To compare contrast material-enhanced magnetic resonance (MR) imaging with resting thallium 201 ((201)Tl) single photon emission computed tomography (SPECT) for predicting myocardial viability in patients early after acute myocardial infarction. MATERIALS AND METHODS: Inversion-recovery contrast-enhanced MR images and resting (201)Tl SPECT images were obtained in 22 patients after acute myocardial infarction. The (201)Tl SPECT images were obtained 4.3 days +/- 0.2 (standard error) after the onset of myocardial infarction. Contrast-enhanced MR imaging was performed 7.9 days +/- 1.6 after (201)Tl SPECT. Transmural extent of hyperenhancement on contrast-enhanced MR images and regional (201)Tl activity were quantitatively analyzed with a 12-segment model. Regional wall thickening on follow-up cine MR images obtained 67 days +/- 17 after contrast-enhanced MR imaging was used as an index for myocardial viability. Statistical analyses were performed with the chi(2) and two-tailed Student t tests. RESULTS: Both contrast-enhanced MR and resting (201)Tl SPECT images showed significant correlations with regional wall thickening on follow-up cine MR images. The sensitivity, specificity, and accuracy of contrast-enhanced MR imaging in the prediction of viable myocardium were significantly higher than those of resting (201)Tl SPECT (98.0% vs 90.3%, P <.01; 75.0% vs 54.4%, P <.05; and 92.0% vs 81.1%, P <.001, respectively). CONCLUSION: Delayed contrast-enhanced MR imaging can help predict myocardial viability as seen on follow-up cine MR images after acute myocardial infarction, with significantly improved sensitivity, specificity, and accuracy in comparison with those of resting (201)Tl SPECT.     

New color imaging of [99mTc]-pyrophosphate and [201Tl]-chloride dual isotope single photon emission computed tomography in acute myocarditis

[99mTc]-pyrophosphate (PYP) and [201Tl]-chloride dual isotope single photon emission computed tomography (SPECT) is now available to detect the site and extent of acute myocardial infarction. In inflammatory myocardial disease, [99mTc]PYP makes hot image on damaged area. We performed dual isotope SPECT of [99mTc]PYP and [201Tl]Cl in two patients with acute myocarditis and severe rhythm disturbance to evaluate the severity of inflammation. Myocardial damage was estimated by [201Tl] perfusion coloring blue and myocardial inflammation was estimated by [99mTc]PYP uptake coloring red. The overlap display of both images made it clear to detect spatial extent of myocardial inflammation. Using this technique, we expect to estimate the severity of myocarditis and to make a decision of therapeutic plan.     

Kinetics of 123I-MIBG after acute myocardial infarction and reperfusion therapy.

Metaiodobenzylguanidine (MIBG) washout from the myocardium has been thought to reflect sympathetic nerve tone. After acute myocardial infarction, however, little is known about this parameter. The aim of this study was to determine the significance of cardiac washout after myocardial infarction and early reperfusion by investigating MIBG kinetics and correlating those kinetics to clinical parameters. METHODS: Sixty patients with acute myocardial infarction underwent planar MIBG and thallium imaging within 14 d of early reperfusion therapy. Global uptake and washout in myocardium, lungs and liver were calculated from early and delayed images. A regional analysis of myocardial kinetics in normal and infarcted myocardium and in an infarct border zone was also performed. Scintigraphic data were correlated with heart-rate variability as an electrophysiologic marker for autonomic tone and prevalence of arrhythmia in 52 patients. Heart-rate variability was described by time-domain indices from long-term electrocardiogram recordings. An age-matched normal control group for MIBG consisted of 10 individuals without heart disease. RESULTS: The infarct patients had preserved left-ventricular ejection fraction (LVEF) (56% +/- 17%). Although late myocardial uptake was expectedly lower in infarct patients compared with healthy volunteers (2.36 +/- 0.66 versus 2.80 +/- 0.55; P = 0.04), global myocardial MIBG washout was faster (11.6% +/- 7.9% versus 0.2% +/- 10.2%, respectively; P = 0.002). Lung and liver kinetics did not differ in patients and healthy volunteers. Global MIBG washout showed a weak but significant positive correlation with the baseline heart rate (r = 0.28, P = 0.03) and an inverse correlation with LVEF (r = -0.28, P = 0.04). Washout was faster in a subgroup of 8 patients with reduced heart-rate variability (16.5% +/- 9.9% versus 10.3% +/- 8.3%; P = 0.04). Regional analysis revealed similar degrees of enhanced MIBG washout for infarcted (low perfusion, low MIBG uptake) and remote myocardium (normal perfusion, high MIBG uptake), whereas the border zone (normal perfusion, low MIBG uptake) showed a nonsignificant trend toward higher washout. CONCLUSION: After myocardial infarction, changes in MIBG kinetics occur specifically in the myocardium, whereas kinetics in lung and liver remain unchanged. Even in patients with left-ventricular function preserved by reperfusion therapy, MIBG washout is abnormal and globally increased. Enhanced washout may reflect increased sympathetic nerve tone and represent increased catecholamine turnover or impaired reuptake in the subacute phase of myocardial infarction.