Myocardial distribution of indium-111-antimyosin Fab in acute inferior and right ventricular infarction: comparison with technetium-99m-pyrophosphate imaging and histologic examination.

In a postmortem study of a 69-yr-old female patient who had suffered 2 yr previously a non-Q-wave anterior infarction and who had sustained just seven days earlier a left inferior and right ventricular infarction, the distribution of 111In-antimyosin Fab was compared to the results of 99mTc-pyrophosphate imaging and histologic examination. Indium-111-antimyosin Fab imaging could not be performed because of cardiogenic shock. However, postmortem gamma scintillation counting revealed increased activities of antimyosin Fab in the inferoapical and right ventricular infarcted regions in which 99mTc-pyrophosphate positive imagings were observed; in contrast, a histologically confirmed old subendocardial anterior infarction had no definite activity. Thus, the myocardial distribution of 111In-antimyosin Fab corresponded well to the results of 99mTc scintigrams and histologic examinations in a human heart, suggesting that this technique could be useful in vivo for detecting several-day-old myocardial infarction of the right ventricle as well as the left ventricle. Tissue from the 2-yr-old infarction was not identified by this technique.     

Indium-111-antimyosin uptake in acute and remote myocardial infarction: comparison with pathohistologic findings.

Indium-111-Fab antimyosin antibody accumulation was studied in an 81-yr-old patient who was treated twice for unstable angina on ECG, signs of apicoseptal infarction, anterolateral and inferior ischemia without clinical evidence of an acute coronary event. During the last hospitalization, 9 and 3 mo after the previous ones, additional ischemia in the inferoposterior wall was demonstrated. Antimyosin was administered to detect acute infarction but pump failure developed and the patient died. Autopsy confirmed all stages of infarction on the anterior and lateral walls, predominant fibrosis in the apicoseptal region and predominant acute necrosis in the inferior wall. Macroscopic and scintigraphic examinations of transverse slices gave concordant results. A mixture of infarctions and normal tissue was confirmed by histologic findings. Antimyosin antibody accumulation was seen in areas of acute necrosis or bordering areas of reduced uptake in myocardium with remote damage, probably caused by prolonged episodes of unstable angina without evident acute coronary event.     

Indium-111 chloride for detecting suspected hepatomas in patients with focal defects on technetium-99m sulfur colloid liver imaging

Twenty-three patients with hepatic cirrhosis and focal defects on Tc-99m sulfur colloid (SC) scintigrams were restudied with In-111 chloride to determine if indium localization in the focal defect is indicative of a hepatoma. Seven of eight patients with proven hepatomas had positive studies; however, six of 15 patients without hepatomas also had studies interpreted as positive. Thus, In-111 chloride is highly sensitive for the detection of hepatomas, and a negative indium study would militate against this diagnosis. The high false-positive rate found may be due to technical factors rather than a lack of specificity of localization; the experience of others seems to support this impression. At present, In-111 chloride scintigraphy for focal hepatic defects appears to be useful in ruling out hepatoma.     

Myocardial distribution of indium-111-antimyosin Fab and technetium-99m-sestamibi in experimental nontransmural infarction.

Early revascularization in acute myocardial infarction results in normal, necrotic and partially damaged and partially salvaged ("intermediate") myocardium. By combining a perfusion tracer and a marker for myocardial injury, we attempted to differentiate between these three types of cardiac tissue. The LAD was occluded in nine pigs for 45 min and then reperfused. After 48 and 72 hr, 74 MBq 111In-antimyosin Fab and 740 MBq 99mTc-sestamibi, respectively, were injected intravenously. Normally perfused myocardium was labeled with fluorescein and the heart excised. Three to four slices were cut from the apex. Tetrazolium staining revealed the zone of necrosis. Tracer distribution on double-nuclide scintigrams of the slices also reflected the three different myocardial zones. Guided by fluorescence and macrohistochemistry, tissue samples were excised from each zone. In relation to normal myocardium, mean activity in the intermediate zone was 0.82 +/- 0.20 for 99mTc-sestamibi and 2.84 +/- 1.31 for 111In-antimyosin Fab. Activity in necrotic myocardium was 0.30 +/- 0.19 and 3.95 +/- 2.47, respectively. These results show that 111In-antimyosin Fab fragments not only accumulate in necrotic but also in intermediate myocardium. Therefore, an overestimation of infarct size may occur if 111In-antimyosin Fab fragments are used alone without a perfusion tracer.     

Indium-111-antimyosin images compared with triphenyl tetrazolium chloride staining in a patient six days after myocardial infarction.

The results of indium-111 (111In) antimyosin imaging during life and the findings on postmortem imaging and triphenyl tetrazolium chloride (TTC) staining of the heart are reported from a patient who received 111In-antimyosin on the sixth day following myocardial infarction and died after imaging the next day. The planar images obtained during life showed abnormal 111In-antimyosin uptake in the posterior, lateral, and apical walls of the left ventricle. Autopsy revealed extensive infarction of the left ventricular lateral and posterior walls with cardiac rupture, which was the cause of sudden death. Direct imaging of the sliced specimen of heart revealed abnormal tracer uptake in the lateral and posterior walls of the left ventricle, which correlated closely with the area of necrosis outlined by TTC staining. Our results confirm the experimental findings that antimyosin antibody binds specifically to the acute irreversibly damaged myocardial cells. A high degree of tracer uptake can be seen even when 111In-antimyosin is injected six days postinfarction.     

Indium-111-leukocyte/technetium-99m-MDP bone and magnetic resonance imaging: difficulty of diagnosing osteomyelitis in patients with neuropathic osteoarthropathy

Fourteen patients (16 sites) with clinical and/or radiographic evidence of neuropathic osteoarthropathy (Charcot joints) were evaluated with combined indium-111-leukocyte (111In-WBC) and technetium-99m-methylene diphosphonate (99mTc-MDP) bone imaging for suspected osteomyelitis. Magnetic resonance (MR) images were obtained in seven patients. Using a positive bone culture as the criterion for the presence of osteomyelitis, there were four true-positive studies, six true-negative sites, and one false-negative 111In-WBC study. Five of 16 sites (31%) had false-positive 111In-WBC uptake at noninfected sites. There were four true-positive and three false-positive MR studies. All false-positives showed at least moderately abnormal findings by both techniques at sites of rapidly progressing osteoarthropathy of recent onset. In this preliminary study, both techniques appear to be sensitive for detection of osteomyelitis, and a negative study makes osteomyelitis unlikely. However, the findings of 111In-WBC/99mTc-MDP and MR images at sites of rapidly progressing, noninfected neuropathic osteoarthropathy may be indistinguishable from those of osteomyelitis.     

111In-antimyosin antibody imaging for detection of myocardial infarction: a quantitative approach

Indium-111-antimyosin imaging has been shown to be a sensitive and specific method for detecting myocardial necrosis, but a quantitative method for interpretation of 111In-antimyosin planar images is lacking. A prospective study was performed in 114 patients with suspected acute myocardial infarction using planar 111In-antimyosin imaging. A ratio of maximum myocardial uptake counts (H) (9 X 9 pixels) over adjacent lung background (L), i.e. H/L ratio, was obtained from 24 and 48 h images. This value was compared with peak creatine kinase (CK) enzyme and left ventricular ejection fraction (LVEF). The patients were classified into groups based upon standard criteria for Q-wave acute myocardial infarction (Q-MI) (n = 50), non-Q-MI (n = 21), unstable angina (n = 15) and those with no evidence of MI or ischaemia (n = 28). The mean +/- S.D. H/L ratio in the Q-MI group was 2.28 +/- 0.50 (24 h, left anterior oblique, LAO, view) and was greater than the non-Q-MI group (1.98 +2- 0.30) (P less than 0.02). In patients with unstable angina (UA), seven had a high ratio (1.75 +/- 0.29) and eight had a lower ratio (1.29 +/- 0.07). In the group of patients without MI or UA, the ratio was 1.24 +/- 0.11 and this was significantly lower than the Q-MI and non-Q-MI groups and those patients with UA and positive 111In uptake (P less than 0.001, respectively). However, there was no significant difference between old MI and patients without evidence of MI or UA.(ABSTRACT TRUNCATED AT 250 WORDS)     

Indium-111 antimyosin monoclonal antibody Fab imaging in patients with cardiomyopathy

Six patients with cardiomyopathy were imaged following intravenous injection of an indium-111 labeled monoclonal antibody directed against the heavy chain of cardiac myosin. Two patients had hypertrophic non-obstructive cardiomyopathy (HNCM), two patients had dilated cardiomyopathy (DCM), and two patients had specific heart muscle disease. One of 2 patients with HNCM and one of 2 patients with DCM had a positive antimyosin scan. The 2 patients with specific heart muscle disease manifested persistent blood pool activity of the antibody, thereby precluding interpretation of the images. The present report demonstrates that antimyosin antibody imaging may provide evidence of myocardial injury, or necrosis in some patients with cardiomyopathy.     

A neutral technetium-99m complex for myocardial imaging

Technetium-99m-CDO-MeB [Bis[1,2-cyclohexanedione-dioximato(1-)- O]-[1,2-cyclohexanedione dioximato(2-)-O]methyl-borato(2-)- N,N',N',N',N',N'')-chlorotechnetium) belongs to a family of compounds generally known as boronic acid adducts of technetium dioxime complexes (BATOs). It has an intrinsic affinity for the myocardium, with negligible lung activity and rapid blood clearance. The uptake of 3.44% ID in rat heart at 1 min postinjection for [99mTc]CDO-MeB versus 3.03% for 201TI indicates high extraction of [99mTc]CDO-MeB by the myocardium. In dogs an ischemic defect is clearly seen in SPECT images obtained 10 min after injection of [99mTc]CDO-MeB. Tissue distribution data in rats show that [99mTc]CDO-MeB is excreted primarily in the feces and to a lesser extent in the urine. Approximately 80% of the activity is excreted within 24 hr after injection.     

Indium-111-labelled antimyosin antibody imaging in a patient with cardiac sarcoidosis

The aetiology of cardiac dysfunction caused by sarcoid granulomatous inflammation may be difficult to clarify, and the potential of imaging methods is limited. We report on a patient who presented with acute biventricular decompensation. Pulmonary sarcoidosis was confirmed after hospitalization. Four weeks after the initiation of corticosteroid treatment, scintigraphy with indium-111-labelled antimyosin antibody Fab fragments (AMAB) revealed distinct activity accumulation in major parts of the left ventricular wall (heart-lung ratio: 1.6) 72 h following injection. There may be a role for AMAB scintigraphy in the early detection of cardiac sarcoidosis.     

Time course of myocardial infarction evaluated by indium-111-antimyosin monoclonal antibody scintigraphy: clinical implications and prognostic value.

To investigate the clinical implications of 111In-antimyosin antibody scintigraphy in the chronic stage of myocardial infarction, 34 studies were performed in 26 patients with 36 infarcts of various infarct ages. The infarcts were divided into three groups according to time from onset of chest pain to scintigraphy. Positive antimyosin images were obtained in 93% of Group I patients (3 days to 1 mo), 71% of Group II patients (1.5 mo to 1 yr) and none were obtained from Group III patients (1.5-6 yr). A negative correlation was observed between antimyosin uptake and the time after myocardial infarction. In Group II, patients with coronary artery patency and patients showing redistribution on exercise 201TI scintigraphy were more likely to have positive antimyosin images compared to patients without these features. Recurrent angina may also relate to chronic antimyosin uptake. Indium-111-antimyosin antibody scintigraphy may be a useful method in assessing the course of myocardial infarction and for the patient follow-up.     

Sensitivity and specificity of Tc-99m-pyrophosphate myocardial scintigraphy for the detection of acute myocardial infarction

Tc-99m-pyrophosphate myocardial scintigraphy was performed on 1,077 patients admitted to the Coronary Care Unit. Results of scintigraphy were compared to the diagnosis as established by ECG, enzymes, and clinical findings to determine the sensitivity and specificity of scintigraphy for the diagnosis of acute myocardial infarction (AMI). Scintigrams were graded according to the intensity of myocardial radioactivity and the distribution pattern of activity as either diffuse or localized. In a coronary care unit, a scintigram of positive intensity grade is 92% sensitive and 68% specific for the diagnosis for AMI. A localized pattern of myocardial radioactivity is 66% sensitive and 93% specific for AMI. With a localized pattern of the highest intensity, the sensitivity is 28% with a specificity of 99.8% for AMI. Therefore, a myocardial scintigram of normal intensity grade excludes the diagnosis of AMI with a 92% probability. A localized pattern is a strong indicator of an AMI and a localized pattern of the greatest intensity is very specific for AMI.     

Indium-111-chloride and three-phase bone scintigraphy: a comparison for imaging experimental osteomyelitis

To investigate the utility of indium-111-chloride (111In-Cl) imaging in detecting osteomyelitis complicating surgical or fracture sites, the proximal tibia of 11 dogs were experimentally infected with Staphylococcus aureus after creation of a cortical defect. The contralateral limb served as a sham-operated control. Animals were serially imaged by radiography, three-phase technetium-99m-methylene diphosphonate (99mTc-MDP) scintigraphy, and 111In-Cl scintigraphy. There was a significant difference between infected (1.93) and noninfected (1.32) limb's tibia/femur count density ratios on 24-hr (p = 0.0001) and 72-hr (p = 0.0001) 111In-Cl images. A smaller difference was found for 99mTc-MDP bone-phase tibia/femur ratios (p = 0.0199). Using receiver operator characteristic analysis of tibia/femur ratios, a sensitivity of 61%, specificity of 88%, and positive (75%) and negative (79%) predictive values were determined for the 24-hr 111In-Cl images. Indium-111-chloride was superior to 99mTc-MDP in differentiating infected and noninfected operative sites.     

99mTc-annexin V and 111In-antimyosin antibody uptake in experimental myocardial infarction in rats

Purpose ^99mTc-annexin V (ANX) allows scintigraphic detection of apoptotic cells via specific binding to exposed phosphatidylserine. In myocardial infarction, apoptosis of myocytes is variable and depends especially on the presence or absence of coronary reperfusion. In this study, ANX uptake in non-reperfused experimental myocardial infarcts was compared with uptake of a marker of myocyte necrosis (¹¹¹In-antimyosin antibodies, AM) and an immunohistochemical marker of apoptosis (Apostain).Methods The left anterior coronary artery was ligated in 47 Wistar rats, which were then injected with ANX (n=20), AM (n=21) or both (n=6). Myocardial uptake of ANX and AM was determined at 2 h (n=14), 4 h (n=14) and 24 h (n=19) after coronary ligation (CL), by quantitative autoradiography with (n=23) or without (n=24) gamma imaging. Heart-to-lung ratios (HLRs) and infarct-to-remote myocardium activity ratios (INRs) were calculated on the scintigrams and autoradiograms respectively. Cardiac sections were stained with haematoxylin-eosin and Apostain. The above studies were repeated in 12 normal rats.Results All rats with CL showed increased ANX and AM uptake in cardiac areas on scintigrams 24 h after CL, with HLRs higher than in controls: 3.1±0.6 versus 1.5±0.3 (p=0.001) for ANX and 1.99±0.44 versus 1.01±0.05 (p<0.0005) for AM. Autoradiography showed intense ANX and AM uptake in infarcts, with comparable topography and INRs at 2 h, 4 h and 24 h after CL (4.6±0.9 versus 5.0±1.8 at 24 h), while Apostain staining was very low (0.06±0.06% of cells).Conclusion In this model of persistent CL, we observed increased ANX uptake in injured myocardium, comparable in intensity, topography and kinetics to that of AM. There was only minimal Apostain staining in the same areas.An editorial commentary on this paper is available at .     

Scintimammography with technetium-99m methoxyisobutylisonitrile: comparison with mammography and magnetic resonance imaging

The aim of the study was to compare the diagnostic accuracy of scintimammography with technetium-99m methoxyisobutylisonitrile (MIBI; SMM) in the detection of primary breast cancer with that of mammography (MM) and magnetic resonance imaging (MRI). Fifty-six patients with suspected lesions detected by palpation or MM were included in the study. Within the 4 weeks preceding excisional biopsy, MM and MRI were performed in all patients. Between 5 and 10 min after the injection of 740 MBq^99mTc-MIBI, SMM in the prone position was performed. In the total group of 56 patients, 43 lesions were palpable, while 13 were non-palpable but were detected by MM. Breast cancer was confirmed by histopathology in 27 of the patients (22 palpable and 5 non-palpable carcinomas). The tumour size ranged from 6 to 80 mm in diameter. For non-palpable lesions, the sensitivity of SMM, MM and MRI was 60%, 60% and 100%, respectively, while the specificity was 75%, 25% and 50%, respectively. For palpable breast lesions, all methods showed high sensitivity (SMM 91%, MM 95%, MRI 91%) but SMM demonstrated significantly higher specificity (SMM 62%, MM 10%, MRI 15%). In two mammographically negative tumours (dense tissue), SMM showed a positive result. In comparison to MRI, one additional carcinoma could be diagnosed by SMM. It may be concluded that for palpable breast lesions, the diagnostic accuracy of SMM is superior to that of MM and MRI. Through the complementary use of SMM it is possible to increase the sensitivity for the detection of breast cancer and multicentric disease. In patients in whom the status of a palpable breast mass remains unclear, SMM may help to reduce the amount of unnecessary biopsies.     

Demonstration of reperfusion after thrombolysis with technetium-99m isonitrile myocardial imaging

Technetium-99m isonitrile myocardial perfusion imaging was employed in a patient undergoing thrombolytic therapy with recombinant tissue plasminogen activator for acute anteroseptal myocardial infarction. Technetium-99m isonitrile does not demonstrate significant myocardial redistribution after intravenous injection. The imaging agent was administered in the emergency room, prior to the initiation of thrombolytic therapy. The initial area at risk for infarction was visualized on images obtained after the patient had been effectively treated. Imaging performed 5 days later, after repeat injection of [99mTc]isonitrile, showed a smaller myocardial perfusion defect indicating salvage of myocardium. Thus, this technique offers promise as a noninvasive means of assessing the area at risk, the success of reperfusion, and the presence of salvaged myocardium, early in the course of acute myocardial infarction.     

Imaging of acute myocardial infarction in pigs with Indium-111 monoclonal antimyosin scintigraphy and MRI

Indium-111 antimyosin F(ab')2 was used in a series of scintigraphic studies on experimentally induced myocardial infarctions in pigs. Antimyosin distribution recorded by planar images of in vivo pigs and by single photon emission computed tomography (SPECT) of excised hearts delineated areas of myocardial necrosis if infarct volume exceeded 3.3 cm3. Scintigraphic images were compared with magnetic resonance images (MRI) obtained from excised hearts and with photographs of slices of the hearts. Infarct size and localization determined with antimyosin were compared. The MR images, with or without gadolinium-DTPA (Gd-DTPA), of the in vivo pigs were all false-negative; some myocardial wall thinning and high bloodpool signals were visible. Results show that both the antimyosin and the MR technique are specific methods for the visualization of induced myocardial necrosis in this animal model. However, the use of antimyosin is limited to a period ranging from 24 to 72 hours after infarction.     

Planar myocardial perfusion imaging with technetium-99m-teboroxime: comparison by vascular territory with thallium-201 and coronary angiography.

Myocardial perfusion agents labeled with 99mTc offer improved physical imaging properties compared to 201TI. Teboroxime is a new 99mTc-labeled compound for myocardial perfusion imaging that shows a high myocardial extraction and rapid clearance. Sixty-seven patients underwent planar teboroxime imaging with a rapid acquisition protocol. Agreement of teboroxime and 201TI for the presence or absence of disease occurred in 56/65 patients (86%). There was agreement (normal or abnormal) between the two agents in 156/195 vessels (80%) and 457/585 segments (78%). When abnormal segments (ischemia or infarction) were compared, teboroxime showed significantly more ischemic segments (89/135, 66%) than did 201TI (73/135, 54%, p < 0.05). Teboroxime offers accuracy comparable to 201TI for the diagnosis of coronary artery disease and may improve the detection of ischemic or viable myocardium. In addition, its rapid myocardial clearance permits stress/rest imaging in 60-90 min.     

Clinical comparison of technetium-99m-N,N-bis(mercaptoacetyl)-2,3-diaminopropanoate with technetium-99m DTPA for renal imaging

We studied 14 patients having serum creatinines of 1.0 to 12.8 mg/dl with either Tc-99m-N,N'-bis(mercaptoacetyl)-2,3-diaminopropanoate (CO2-DADS) or Tc-99m DTPA, and within 48 hours with the other agent. Analog and digital images of the kidneys and bladder were acquired for 30 minutes after injection and after voiding. The kidney-to-background ratio at 3 minutes for Tc-99m CO2-DADS was 2.01 +/- 0.79 (mean +/- SD) times that for Tc-99m DTPA (P less than 0.001). The parenchymal transit time for Tc-99m CO2-DADS was 1.34 +/- 0.25 (mean +/- SD) times that for Tc-99m DTPA (P less than 0.005). The percent-excreted dose at 30 minutes for Tc-99m CO2-DADS was 2.57 +/- 1.24 (mean +/- SD) times that for Tc-99m DTPA (P less than 0.001). Analog Tc-99m CO2-DADS images showed spatial resolution comparable to that for Tc-99m DTPA. Hepatobiliary excretion was never seen. Tc-99m CO2-DADS appears to be generally superior to Tc-99m DTPA as a renal radiopharmaceutical.     

Detection of residual wall motion after myocardial infarction by gated technetium-99m tetrofosmin SPET: a comparison with contrast ventriculography

The differentiation of residual viability from necrotic myocardium in patients with a prior myocardial infarction is important when deciding whether revascularization is indicated. Myocardial viability can be assessed by studying perfusion and regional wall motion. Gated single-photon emission tomography (SPET) imaging allows the simultaneous assessment of perfusion and function through a single study. The aim of this study was to analyse the concordance between wall motion score derived by gated SPET and by contrast ventriculography. Furthermore, the agreement between myocardial perfusion and regional myocardial wall motion was analysed for both techniques. We studied a homogeneous group of 26 consecutive patients with a prior myocardial infarction, using both gated technetium-99m tetrofosmin SPET and contrast ventriculography. A seven-segment model of the left ventricle was employed to score regional myocardial wall motion on images obtained with gated SPET and contrast ventriculography using a four-point scale. Contrast ventriculography was performed within 2 weeks of the gated SPET study. Prevalence of abnormal wall motion (akinetic or dyskinetic) was 24/182 (13%) for gated SPET and 25/182 (14%) for contrast ventriculography (P = NS). There was a high agreement (80%) in wall motion score between gated SPET and contrast ventriculography (kappa = 0.67, P < 0.001). The agreement was better in segments with normal or mild to moderate hypoperfusion (82%, kappa = 0.69) than in those with severe hypoperfusion (67%, kappa = 0.56). The agreement between myocardial perfusion and myocardial wall motion was 89% (162/182), kappa = 0.57, for gated SPET and 80% (145/182), kappa = 0.21, for contrast ventriculography. The relation between the summed wall motion scores per patient on gated SPET and contrast ventriculography was excellent (y = 0.81x + 2.9, r = 0.82, P < 0.01). Thirteen (43%) out of 30 segments with severely diminished or no myocardial perfusion showed normal or hypokinetic wall motion on gated SPET, suggesting residual myocardial viability in malperfused regions. Our results suggest that gated SPET imaging is a reliable tool for the assessment of regional wall motion in post-myocardial infarction patients. Furthermore, in patients with a previous myocardial infarction, gated SPET imaging has the potential to detect preserved wall motion in regions with fixed perfusion defects, which might be indicative of residual myocardial viability.