The localization of myocardial ischaemia with technetium-99m methoxy isobutyl isonitrile and single photon emission computed tomography

Thirty-two patients with suspected coronary artery disease were studied by single photon emission computed tomography (SPECT) imaging with oblique reconstructions of the myocardium following the intravenous administration of technetium-99m methoxy isobutyl isonitrile at peak exercise. All patients also underwent three-vessel coronary angiography. The SPECT technique produced very detailed images allowing easy delineation of localized myocardial defects. Segmental myocardial uptake defects were compared with diseased vessels as shown at angiography. A good correlation was shown between right coronary artery (RCA) disease and mid and proximal inferior segments and between left circumflex (LCx) artery disease and mid and proximal lateral segments, allowing accurate localization of a defect to one of these two vessels' territories. Sensitivity and specificity of detection of disease of the RCA and LCx artery were high. Defects associated with a lesion of the left anterior descending vessel were more variable.     

Simultaneous assessment of wall motion and myocardial perfusion by technetium-99m methoxy isobutyl isonitrile

The aim of this study was to assess whether or not myocardial uptake of Technetium-99m methoxy isobutyl isonitrile (Tc-MIBI) indicated myocardial viability. We performed simultaneous Tc-MIBI angiography and myocardial SPECT at rest on 12 patients with suspected coronary artery disease. Left ventricle was divided into 3 segments, and regional wall motion was graded as normal, hypokinesis and akinesis/dyskinesis. Myocardial uptake of Tc-MIBI was assessed as normal, reduced and absent in each segment. In segments with normal and reduced Tc-MIBI uptake, 7% (2 of 28) and 33% (2 of 6) showed wall motion abnormalities of akinesis/dyskinesis, respectively. However, all segments with absent Tc-MIBI uptake had asynergy of akinesis/dyskinesis (2 of 2, 100%). Myocardial Tc-MIBI uptake at rest indicated wall motion abnormalities and was considered to be useful for the evaluation of myocardial viability. First-pass radionuclide angiography followed by myocardial SPECT with Tc-MIBI demonstrated to be useful for the simultaneous assessment of the left ventricular wall motion and myocardial perfusion.     

Quantitative exercise technetium-99m tetrofosmin myocardial tomography for the identification and localization of coronary artery disease

The aim of this study was to evaluate the accuracy of quantitative 1-day exercise-rest technetium-99m tetrofosmin tomography in the identification of patients with coronary artery disease (CAD) and in the detection of individual stenosed coronary vessels. Sixty-one patients with suspected CAD who underwent coronary angiography and 13 normal volunteers were studied. All patients were submitted to two i.v. injections of^99mTc-tetrofosmin, one at peak exercise (370 MBq) and the other (1110 MBq) at rest 3 h after exercise (images 15–30 min after injection for both studies). All patients with CAD (0% luminal stenosis) (n=50) had an abnormal^99mTc-tetrofosmin tomogram. Only one patient without significant coronary narrowing showed abnormal findings. Overall sensitivity, specificity and diagnostic accuracy in the detection of individual stenosed vessels were 77%, 93% and 85%, respectively. Sensitivity and diagnostic accuracy in the identification of individuals stenosed coronary vessels were significantly higher (P<0.05) in patients with single-vessel disease (n=21) than in those with multivessel disease (n=29). Sensitivity, specificity and accuracy for detecting individual diseased vessels were similar in patients without previous myocardial infarction (n=26) and in those with previous myocardial infarction (n=35). In myocardial territories related to non-infarcted areas (n=128), sensitivity and specificity in the detection of stenosed vessels were 70% and 95%, respectively. In infarcted areas (n=55), sensitivity and specificity in the detection of stenosed vessels were 85% (P=NS vs non-infarcted areas) and 75% (P<0.05 vs non-infarcted areas), respectively. Finally, sensitivity was significantly lower (P<0.05) in vascular territories supplied by vessels with moderate stenosis (50%–75%) than in those supplied by vessels with severe stenosis (>75%). The results of this study demonstrate that quantitative 1-day exercise-rest^99mTc-tetrofosmin single-photon emission tomographic imaging is a suitable and accurate technique to identify patients with CAD and to detect individual stenosed coronary vessels.     

Comparison between exercise and trans-oesophageal atrial pacing in patients with coronary artery disease: technetium-99m methoxy isobutyl isonitrile simultaneous evaluation of ventricular function and myocardial perfusion

In this study we compared the results of exercise and trans-oesophageal atrial pacing (TAP) technetium-99m methoxyisobutyl isonitrile (^99mTc-SESTAMIBI) cardiac imaging in the evaluation of left ventricular (LV) function and myocardial perfusion in patients with angiographically proven coronary artery disease. Ten patients (8 men and 2 women, mean age 59 ± 6 years) were submitted to 3 separate injections of ^99mTc-SESTAMIBI, one under control conditions, one after exercise and one after TAP. LV ejection fraction, as measured by electrocardiogram (ECG) gated first pass, decreased from 49 ± 5 % under control conditions to 42 ±6% during exercise (P < 0.05 versus control) and to 43 ±8 % during TAP (P<0.05 versus control and insignificant change versus exercise). Segmental myocardial perfusion analysis was performed on a total of 150 myocardial segments. On both exercise and TAP ^99mTc-SESTAMIBI studies, 103 segments (69% of the total) were normal, 32 (21 %) had reversible, and 15 (10%) irreversible, perfusion defects. Relative regional tracer uptake was not statistically different between exercise and TAP in normal regions (91.1 ± 9.1 % versus 90.7 ± 8.5 %, respectively), in regions with reversible (61.9±12% versus 62.4±10.4%, respectively) and irreversible perfusion defects (55.8 ± 7.8 % versus 58.8 ± 9.5 %, respectively). Our results demonstrated that ^99mTc-SESTAMIBI TAP cardiac imaging shows similar results to ^99mTc-SESTAMIBI exercise myocardial scintigraphy in the assessment of LV function and myocardial perfusion in patients with coronary artery disease.This work was partially supported by a grant from the Italian National Council of Research (CNR) (Special Project Immagini Biomediche in-Vivo)     

Comparison between exercise and trans-oesophageal atrial pacing in patients with coronary artery disease: technetium-99m methoxy isobutyl isonitrile simultaneous evaluation of ventricular function and myocardial perfusion.

In this study we compared the results of exercise and trans-oesophageal atrial pacing (TAP) technetium-99m methoxyisobutyl isonitrile (99mTc-SESTAMIBI) cardiac imaging in the evaluation of left ventricular (LV) function and myocardial perfusion in patients with angiographically proven coronary artery disease. Ten patients (8 men and 2 women, mean age 59 +/- 6 years) were submitted to 3 separate injections of 99mTc-SESTAMIBI, one under control conditions, one after exercise and one after TAP. LV ejection fraction, as measured by electrocardiogram (ECG) gated first pass, decreased from 49 +/- 5% under control conditions to 42 +/- 6% during exercise (P less than 0.05 versus control) and to 43 +/- 8% during TAP (P less than 0.05 versus control and insignificant change versus exercise). Segmental myocardial perfusion analysis was performed on a total of 150 myocardial segments. On both exercise and TAP 99mTc-SESTAMIBI studies, 103 segments (69% of the total) were normal, 32 (21%) had reversible, and 15 (10%) irreversible, perfusion defects. Relative regional tracer uptake was not statistically different between exercise and TAP in normal regions (91.1 +/- 9.1% versus 90.7 +/- 8.5%, respectively), in regions with reversible (61.9 +/- 12% versus 62.4 +/- 10.4%, respectively) and irreversible perfusion defects (55.8 +/- 7.8% versus 58.8 +/- 9.5%, respectively). Our results demonstrated that 99mTc-SESTAMIBI TAP cardiac imaging shows similar results to 99mTc-SESTAMIBI exercise myocardial scintigraphy in the assessment of LV function and myocardial perfusion in patients with coronary artery disease.     

Diagnostic accuracy of dipyridamole technetium 99m-labeled sestamibi myocardial tomography for detection of coronary artery disease

Background

The diagnostic accuracy of exercise ^99mTc-labeled sestamibi and intravenous dipyridamole ²⁰¹Tl-labeled myocardial tomography is established. The accuracy of dipyridamole stress ^99mTc-labeled sestamibi myocardial tomography for the detection of coronary artery disease has not been reported.

Methods and Results

Our purpose was to determine the diagnostic accuracy of same-day, rest-dipyridamole stress ^99mTc-labeled sestamibi myocardial single-photon emission computed tomography (SPECT) compared with coronary angiography. Two hundred forty-four patients who were unable to exercise adequately underwent both dipyridamole ^99mTc-labeled sestamibi SPECT and coronary angiography within 6 months. Dipyridamole was administered intravenously in a standard dose of 0.56 mg/kg for 4 minutes. Cardiac and noncardiac side effects were recorded. The presence of coronary stenoses of 50% or greater diameter reduction in each of the major coronary arteries was compared with imaging data in corresponding myocardial perfusion beds. The patient population was predominately (98.8%) male with a mean age of 63±9 years (range 33 to 83 years). The majority of patients had stable angina (88%). Eighty-four patients (35%) gave a prior history of myocardial infarction; 44 patients (18%) had a history of congestire heart failure. The principal limitation to exercise stress was peripheral vascular disease in 62 patients (26%). No serious side effects occurred during dipyridamole stress; 14% of patients had chest pain and 8% of patients had 1 mm or greater ST segment depression. Of the 204 patients with documented coronary stenoses, 43 (21%) had single-vessel disease and 161 (79%) had multivessel disease. The sensitivity was 93% (40/43 in patients with single-vessel disease) and 91% (146/161 in patients with multivessel disease). Overall sensitivity was 91%. The specificity was 28% (11/40) in this population with a high prestest probability of coronary artery disease and posttest referral for cardiac catheterization.

Conclusion

^99mTc-labeled sestamibi myocardial tomography in conjunction with intravenous dipyridamole stress is a safe and sensitive method for the detection of coronary artery disease. The diagnostic accuracy of dipyridamole stress ^99mTc-labeled sestamibi SPECT for the detection of coronary artery disease is similar to that reported for exercise stress ^99mTc-labeled sestamibi tomography, making this a suitable alternative for the evaluation of patients who are unable to exercise adequately.     

Left ventricular dysfunction in coronary artery disease: Comparison between rest-redistribution thallium 201 and resting technetium 99m methoxyisobutyl isonitrile cardiac imaging

Background

We compared rest-redistribution thallium 201 and resting technetium 99m methoxyisobutyl isonitrile (MIBI) cardiac imaging in 29 men with angiographically proven coronary artery disease and regional ventricular dysfunction. Left ventricular ejection fraction at radionuclide angiography was 35%±9%.

Methods and Results

Regional left ventricular wall motion was assessed on gated^99mTc MIBI images according to a 3-point scale (0=normal, 1=hypokinetic, 2=akinetic or dyskinetic).²⁰¹Tl and^99mTc MIBI uptake values were analyzed quantitatively. A total of 435 myocardial segments were classified on the basis of wall motion analysis into three groups: group 1 (normal wall motion;n=201), group 2 (hypokinetic;n=132), and group 3 (akinetic or dyskinetic;n=102).²⁰¹Tl and^99mTc MIBI uptake values were significantly higher in groups 1 and 2 compared with group 3 (p<0.05) and in group 1 compared with group 2 (p<0.05). When²⁰¹Tl and^99mTc MIBI uptake values were directly compared, no significant differences in groups 1 and 2 were observed. In group 3,^99mTc MIBI uptake (67%±14%) was significantly lower (p<0.001) than initial (72%±11%) and delayed²⁰¹Tl uptake (73%±12%).

Conclusion

Thus rest-redistribution²⁰¹Tl and resting^99mTc MIBI cardiac imaging reflect the severity of left ventricular dysfunction in coronary artery disease. However, in segments with severely impaired regional ventricular function,²⁰¹Tl uptake is significantly higher than^99mTc MIBI uptake.     

Accuracy of stress Tc-99m tetrofosmin myocardial perfusion tomography for the diagnosis and localization of coronary artery disease in women

Background  Earlier studies have suggested a modest accuracy of stress thallium 201 myocardial perfusion imaging (MPI) for the diagnosis of coronary artery disease (CAD) in women. The accuracy of stress MPI with technetium 99m tetrofosmin has not been studied in women. The aim of this study was to assess the accuracy of stress Tc-99m tetrofosmin MPI for the diagnosis and localization of CAD in women. Methods and Results  We studied 88 women who underwent exercise or dobutamine stress Tc-99m tetrofosmin tomography and coronary angiography within 3 months. Significant CAD was defined as a stenosis 50% or greater in diameter in at least 1 major epicardial coronary artery. Myocardial perfusion abnormalities were detected in 44 of 53 patients with significant CAD and in 7 of 35 patients without significant CAD (overall sensitivity, 83% [95% confidence interval (CI), 73%-93%]; specificity, 80% [95% CI, 67%-93%]; and accuracy, 82% [95% CI, 74%-90%]). The sensitivity was 72% (18/25) in patients with single-vessel CAD and 93% (26/28) in patients with multivessel CAD. Perfusion abnormalities were detected in 2 or more vascular distributions in 20 of 28 patients with multivessel CAD and in 4 of 60 patients without multivessel CAD (sensitivity for the identification of multivessel CAD, 71% [95% CI, 55%-88%]; specificity, 93% [95% CI, 86%-98%]; and accuracy, 86% [95% CI, 79%-93%]). The sensitivity, specificity, and accuracy were 82%, 84%, and 83%, respectively, for the diagnosis of CAD in the left anterior descending artery; 77%, 84%, and 81%, respectively, for CAD in the right coronary artery; and 74%, 80%, and 78%, respectively, for CAD in the left circumflex artery. Conclusion  Stress Tc-99m tetrofosmin MPI is an accurate noninvasive technique for the diagnosis and localization of CAD in women. Supported in part by a publication grant from GE Healthcare     

99mTc-hexakis methoxy isobutyl isonitrile MIBI scintigraphy and bronchoalveolar fluid lactic dehydrogenase in pulmonary tuberculosis

In cases of chronic pulmonary tuberculosis (PTB) with negative sputum smears, particularly when they are symptomatic, physicians encounter problems in differentiating the active from the inactive stage of the disease. This study was undertaken to determine the usefulness of technetium-99m hexakis methoxy isobutyl isonitrile ((99m)Tc-MIBI) pulmonary scintigraphy and lactic dehydrogenase (LDH) in bronchoalveolar lavage fluid (BALF), in differentiating active from inactive PTB. According to the methods we used, BALF LDH level was measured in 12 patients with documented active PTB (Group 1) before of treatment and in 7 patients with treated PTB (Group 2) after treatment. Lung scan with (99m)Tc-MIBI was performed in 7/12 patients of Group 1 (Group 1a) and in all of Group 2. Five patients of Group 1 refused the lung scan (Group 1b). Five adults who had a normal myocardial perfusion scan were considered as normal lung cases (Group 3). Our results showed that the mean LDH level in BALF was not statistically higher in Group 1 (252.42+/-189.06 mIU/ml) than in Group 2 (106.28+/-139.99 mIU/ml). Very low values, less than 24 mIu/ml, excluded active PTB. Of the 7 patients of Group 1a, 6 had a positive lung scan (85.7%). Of the 7 patients of Group 2, 6 had negative lung scan (85.7%). Both tests had a positive correlation in differentiating active and inactive PTB. In conclusion, although none of the tests were specific for PTB, low BALF LDH of less than 24 mIUL and negative (99m)Tc-MIBI pulmonary scintigraphy, seemed to indicate inactive PTB. If our findings are confirmed by others with more related cases, these tests can be shown useful in the follow up of treated PTB patients.     

Amplitude analysis of stress technetium-99m methoxy isobutylisonitrile images in coronary artery disease

To determine the role of rest and stress gated technetium-99m methoxyisobutylisonitrile (sestamibi), in the detection of coronary artery disease, routine Fourier analysis of these images was performed with the best septal left anterior oblique (LAO) position of 20 patients (17 men, 3 women; aged 40–75 years) who also underwent rest or redistribution/stress single photon emission tomography (SPET) (^99mTc-sestamibi and Thallium-201), gated blood pool imaging and coronary angiogram. There were 6 patients with single-vessel disease, 6 with two-vessel disease, 4 with three-vessel disease, 2 with coronary spasms, 1 with a patent graft and 1 with anginal episodes but a normal angiogram result. Three normal volunteers (2 women, 1 man; aged 24–26 years) also had rest and stress gated blood pool as well as rest and stress gated ^99mTc-sestamibi imaging. Rest and stress ^99mTc-ses-tamibi amplitude and phase images depicted regional myocardial wall shortening from the outer layer of the myocardium to the center of the left ventricle as follows a high amplitude halo of maximal negative count rate variaton; a circular thinner halo of negligible amplitude; a central region of maximal positive count rate variation, as the images evolved from end-diastole to end-systole. Similar patterns with regional differences represented abnormal myocardial wall shortening. (^99mTc-sestamibi and ²⁰¹T1 SPET) images were in agreement in 90% of the patients and 92% of myocardial regions. ²⁰¹T1 SPET detected 83% of angiographically proven lesions, as compared with 80% for ^99mTc-setamibi SPET and 80% for the amplitude images. The amplitude images demonstrated a larger number of other abnormalities not predicted on the angiogram, probably because they were able to detect regions with a potential for flow improvement and transient regional wall shortening abnormalities. Amplitude and phase analyses of gated rest and stress ^99mTc-ses-tamibi images are easy to perform and may become an important adjunct to (^99mTc-sestamibi SPET) images for a complete evaluation of both regional myocardial perfusion and regional contractile function using a single tracer. Offprint requests to: E.E. Camargo     

Clinical comparison between thallium-201 and Tc-99m-methoxy isobutyl isonitrile (hexamibi) myocardial perfusion imaging for detection of coronary artery disease

99mTc-hexamibi (methoxy isobutyl isonitrile) is a new 99mTc-hexakis analog that can be used as a myocardial perfusion imaging agent. The purposes of this study were to compare 99mTc-hexamibi to 201Tl-thallous chloride myocardial stress scintigraphy in patients referred for investigation of chest pain and to evaluate the sensitivity of 99mTc-hexamibi in detection of coronary artery disease. One hundred patients were prospectively studied with both 201Tl and 99mTc-hexamibi planar imaging. Sixty five patients had a current coronary angiography. There was a total of 97 significantly (less than or equal to 70%) stenosed major coronary arteries. 99mTc-hexamibi (25 mCi) study was done within a week of the 201Tl scan with similar double products upon standard treadmil stress testing. Rest studies with 99mTc-hexamibi were obtained 24-48 h after the stress test using the same acquisition parameters and dose. Analysis was performed blind by three observers. The left ventricle was divided into five segments in each image. Analysis of 201Tl and 99mTc-hexamibi results in 1500 left ventricle segments showed an overall agreement in 1326/1500 (88.4%) segments. Correlation between the patient diagnosis on the 201Tl and 99mTc-hexamibi studies showed an agreement in 89 patients (89%). 201Tl revealed myocardial uptake defects in 526 segments, detecting 72 out of 97 (74.2%) significantly stenosed coronary arteries and 99mTc-hexamibi detected 513 segments corresponding to 68 (70.1%) stenosed arteries (no significant statistical difference). In conclusion, these results show a good correlation between 201Tl and 99mTc-hexamibi myocardial imaging in the detection of significant coronary artery disease.     

Clinical comparison between thallium-201 and Tc-99m-methoxy isobutyl isonitrile (hexamibi) myocardial perfusion imaging for detection of coronary artery disease

^99mTc-hexamibi (methoxy isobutyl isonitrile) is a new ^99mTc-hexakis analog that can be used as a myocardial perfusion imaging agent. The purposes of this study were to compare ^99mTc-hexamibi to ²⁰¹Tl-thallous chloride myocardial stress scintigraphy in patients referred for investigation of chest pain and to evaluate the sensitivity of ^99mTc-hexamibi in detection of coronary artery disease. One hundred patients were prospectively studied with both ²⁰¹Tl and ^99mTc-hexamibi planar imaging. Sixty five patients had a current coronary angiography. There was a total of 97 significantly (70%) stenosed major coronary arteries. ^99mTc-hexamibi (25 mCi) study was done within a week of the ²⁰¹Tl scan with similar double products upon standard treadmil stress testing. Rest studies with ^99mTc-hexamibi were obtained 24–48 h after the stress test using the same acquisition parameters and dose. Analysis was performed blind by three observers. The left ventricle was divided into five segments in each image. Analysis of ²⁰¹Tl and ^99mTc-hexamibi results in 1500 left ventricle segments showed an overall agreement in 1326/1500 (88.4%) segments. Correlation between the patient diagnosis on the ²⁰¹Tl and ^99mTc-hexamibi studies showed an agreement in 89 patients (89%). ²⁰¹Tl revealed myocardial uptake defects in 526 segments, detecting 72 out of 97 (74.2%) significantly stenosed coronary arteries and ^99mTc-hexamibi detected 513 segments corresponding to 68 (70.1%) stenosed arteries (no significant statistical difference). In conclusion, these results show a good correlation between ²⁰¹Tl and ^99mTc-hexamibi myocardial imaging in the detection of significant coronary artery disease.     

Same day injections of Tc-99m methoxy isobutyl isonitrile (hexamibi) for myocardial tomographic imaging: Comparison between rest-stress and stress-rest injection sequences

It has been shown that both rest and stress ^99mTc-hexamibi myocardial perfusion imaging can be performed on the same day using two different doses injected within few hours (the first one at rest followed by a second at stress). In order to evaluate and compare 2 sequences (rest-stress and stress-rest) of ^99mTc-hexamibi injections performed the same day, 18 patients with either abnormal ²⁰¹Tl myocardial scan or abnormal coronary angiography were studied with 2 ^99mTc-hexamibi injections protocols. The rest-stress study was performed as follows: 7 mCi ^99mTc-hexamibi was injected at rest. Single photon emission computed tomography (SPECT) was performed 60 min later. Immediately after the rest study, patients were injected at peak stress with 25 mCi ^99mTc-hexamibi. Tomographic imaging was repeated 1 h later. Patients were submitted to the stress-rest protocol within 3 days. Tomographic imaging was done 1 h after a 7 mCi injection at stress. This study was followed by an injection of 25 mCi ^99mTc-hexamibi at rest, a tomographic study was performed 60 min later. Myocardial sections were reconstructed in horizontal long, vertical long, and short axes. Data analysis also included polar map representation. A total of 324 segments were interpreted blind by 3 observers, there was an agreement in 283/324 (87.3%) segments between the 2 protocols. However, 24 segments (7.4%) judged ischemic on rest-stress were called scars on stress-rest. In three patients, myocardial segments were judged normal on the rest image of the rest-stress protocol while they were found abnormal (false positive images) on the stress-rest sequence. Stress images from both protocols were judged similar in 17 patients. In conclusion, when using a short time interval (less than 2 h) between two ^99mTc-hexamibi injections, it is preferable to do a rest-stress sequence since the rest image performed initially represents a true rest study, which is not necessarily the case with the stress-rest sequence.     

Same day injections of Tc-99m methoxy isobutyl isonitrile (hexamibi) for myocardial tomographic imaging: comparison between rest-stress and stress-rest injection sequences

It has been shown that both rest and stress 99mTc-hexamibi myocardial perfusion imaging can be performed on the same day using two different doses injected within few hours (the first one at rest followed by a second at stress). In order to evaluate and compare 2 sequences (rest-stress and stress-rest) of 99mTc-hexamibi injections performed the same day, 18 patients with either abnormal 201Tl myocardial scan or abnormal coronary angiography were studied with 2 99mTc-hexamibi injections protocols. The rest-stress study was performed as follows: 7 mCi 99mTc-hexamibi was injected at rest. Single photon emission computed tomography (SPECT) was performed 60 min later. Immediately after the rest study, patients were injected at peak stress with 25 mCi 99mTc-hexamibi. Tomographic imaging was repeated 1 h later. Patients were submitted to the stress-rest protocol within 3 days. Tomographic imaging was done 1 h after a 7 mCi injection at stress. This study was followed by an injection of 25 mCi 99mTc-hexamibi at rest, a tomographic study was performed 60 min later. Myocardial sections were reconstructed in horizontal long, vertical long, and short axes. Data analysis also included polar map representation. A total of 324 segments were interpreted blind by 3 observers, there was an agreement in 283/324 (87.3%) segments between the 2 protocols. However, 24 segments (7.4%) judged ischemic on rest-stress were called scars on stress-rest.(ABSTRACT TRUNCATED AT 250 WORDS)     

Direct comparison of technetium 99m-sestamibi and technetium 99m-tetrofosmin cardiac single photon emission computed tomography in patients with coronary artery disease

Background  Technetium 99m-labeled sestamibi and tetrofosmin tomography have shown high diagnostic accuracy in the detection of coronary artery disease (CAD). However, few data are available comparing sestamibi and tetrofosmin imaging in the same patients. The aim of the study was to determine the image quality of the two tracers and to compare the results of exercise sestamibi and tetrofosmin tomography in the same patients. Methods  The results of exercise-rest sestamibi and tetrofosmin myocardial tomography were compared in 32 patients with suspected or known CAD who underwent coronary angiography. Image quality was evaluated subjectively. Regional tracer distribution was visually assessed and quantitatively measured in 22 segments/patient. Results  At coronary angiography 7 patients had normal coronary vessels, 11 single-vessel, and 14 multivessel CAD (≥50% luminal stenosis). Image quality judged visually was comparable with the two tracers. Heart/lung and heart/liver ratios for sestamibi and tetrofosmin were not different. At visual analysis, 68% of the patients with CAD had abnormal findings with sestamibi and 76% with tetrofosmin (p=NS). At quantitative analysis, 92% of the patients with CAD had abnormal findings with sestamibi and 96% with tetrofosmin (p=NS). At both visual and quantitative analyses, sensitivity, specificity, and diagnostic accuracy in the detection of individual stenosed vessels were not different between the two tracers. Moreover, for both tracers sensitivity, specificity, and diagnostic accuracy in the detection of diseased vessels were significantly higher (all p<0.05) at quantitative compared with visual analysis. Finally, defect size and severity were similar for the two tracers. Conclusions  Exercise-rest sestamibi and tetrofosmin tomography yielded images of comparable quality and provided similar results in the identification of patients with CAD and in the detection of the individual stenosed coronary vessels.     

Amplitude analysis of stress technetium-99m methoxy isobutylisonitrile images in coronary artery disease.

To determine the role of rest and stress gated technetium-99m methoxyisobutylisonitrile (sestamibi), in the detection of coronary artery disease, routine Fourier analysis of these images was performed with the best septal left anterior oblique (LAO) position of 20 patients (17 men, 3 women; aged 40-75 years) who also underwent rest or redistribution/stress single photon emission tomography (SPET) (99mTc-sestamibi and Thallium-201), gated blood pool imaging and coronary angiogram. There were 6 patients with single-vessel disease, 6 with two-vessel disease, 4 with three-vessel disease, 2 with coronary spasms, 1 with a patent graft and 1 with anginal episodes but a normal angiogram result. Three normal volunteers (2 women, 1 man; aged 24-26 years) also had rest and stress gated blood pool as well as rest and stress gated 99mTc-sestamibi imaging. Rest and stress 99mTc-sestamibi amplitude and phase images depicted regional myocardial wall shortening from the outer layer of the myocardium to the center of the left ventricle as follows: a high amplitude halo of maximal negative count rate variation; a circular thinner halo of negligible amplitude; a central region of maximal positive count rate variation, as the images evolved from end-diastole to end-systole. Similar patterns with regional differences represented abnormal myocardial wall shortening. 99mTc-sestamibi and 201Tl SPET images were in agreement in 90% of the patients and 92% of myocardial regions. 201Tl SPET detected 83% of angiographically proven lesions, as compared with 80% for 99mTc-setamibi SPET and 80% for the amplitude images. The amplitude images demonstrated a larger number of other abnormalities not predicted on the angiogram, probably because they were able to detect regions with a potential for flow improvement and transient regional wall shortening abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)     

Accuracy of 99mTc-tetrofosmin myocardial tomography in the evaluation of coronary artery disease

BACKGROUND: Technetium 99m-labeled myocardial agents have been proposed as an alternative to thallium 201. The aim of this study was to assess retrospectively the accuracy of exercise myocardial 99mTc-tetrofosmin scintigraphy with tomographic imaging (SPECT) in a large group population in the evaluation of coronary artery disease. Furthermore we evaluated the relation between the severity of scintigraphic impaired myocardial perfusion and the angiographic coronary artery stenoses in patients without myocardial infarction and with stenosis localized exclusively in the proximal segment of the 3 main coronary arteries. METHODS AND RESULTS: The study group consisted of 235 consecutive patients, 204 (87%) of whom were men, with a mean age of 57+/-10 years, and with suspected or known coronary artery disease, who underwent 99mTc-tetrofosmin SPECT and coronary angiography. Furthermore, 61 patients in a low-likelihood group for coronary artery disease were also studied. Significant disease was defined by > or = 50% luminal coronary artery stenosis in > or = 1 native coronary artery or major branch or in a saphenous vein graft or arterial mammary graft. The overall sensitivity was 95%, specificity was 76%, and predictive accuracy was 95%. The normalcy rate for the low-likelihood group was 93%. Sensitivity was 71% for the left anterior descending artery, 61% for the left circumflex artery, and 73% for the right coronary artery. Specificity was 94% for the left anterior descending artery, 96% for the left circumflex artery, and 91% for the right coronary artery. Predictive accuracy was 79% for the left anterior descending artery, 78% for the left circumflex artery, and 81 % for the right coronary artery. In patients without myocardial infarction linear regression analysis between scintigraphy and angiography showed a significant correlation in patients with severe proximal coronary artery stenosis (r = 0.53, P < .002), but not in those with moderate proximal stenosis (r = 0.31, P = NS). CONCLUSIONS: This study shows that 99mTc-tetrofosmin SPECT is accurate in the detection of coronary artery disease. The relation of the severity of scintigraphic impaired myocardial perfusion and angiographic coronary artery stenosis, however, may differ significantly in patients with proximal stenosis of different severity.     

Segmental analysis of SPECT99mTc-methoxy isobutyl isonitrile and201Tl myocardial imaging in ischaemic heart disease

To study the potential usefulness of^99mTc-methoxy isobutyl isonitrile (^99mTc-MIBI) as a substitute for²⁰¹Tl in assessing patients with ischaemic heart disease, 24 patients underwent 1 day rest and exercise^99mTc-MIBI single photon emission computerised topography (SPECT) 1 week after SPECT exercise²⁰¹Tl. All patients were catheterized within 1 month after myocardial imaging. In 17 patients, resting first pass radionuclide angiography (FPRNA) was performed with^99mTc-MIBI. The heart to lung ratio for^99mTc-MIBI and²⁰¹Tl was calculated both at rest and exercise. The segmental analysis for myocardial perfusion reveals that 87/96 segments (91 %) were correctly classified by SPECT²⁰¹Tl and 84/96 segments (88%) were correctly classified by^99mTc-MIBI. A significant correlation was present between LVEF measured by^99mTc-MIBI FPRNA and contrast ventriculography (r = 0.85,P < 0.0001). The heart to lung ratio both at rest and exercise for^99mTc-MIBI is significantly higher than²⁰¹Tl (P < 0.01 and <0.001 respectively). We conclude that^99mTc-MIBI is a promising agent for simultaneous evaluation of myocardial perfusion and cardiac function.