99m Tc-MIBI心肌显像对冠状动脉病变的定位研究

目的：探讨９９ｍＴｃ－ＭＩＢＩ心肌显像在检出冠心病病变心肌节段和病变血管定位上的价值。方法：对照分析２０例冠心病和５例对照组冠状动脉造影与９９ｍＴｃ－ＭＩＢＩ单光子发射断层显像（ＳＰＥＣＴ）的结果。结果：潘生丁负荷ＳＰＥＣＴ检出冠心病、病变血管和病变心肌节段的敏感性分别为９５．００％、６３．６４％和４３．６８％明显高于静息相的６０．００％、４２．４２％和２７．５９％（Ｐ＜０．０１）。与静息相比较,潘生丁负荷ＳＰＥＣＴ多发现３３．３３％的病变血管和３６．８４％的病变心肌节段。对病变血管的敏感性,ＬＡＤ高于ＲＣＡ和ＬＣＸ;对于病变心肌节段检测敏感性ＲＣＡ支配节段高于ＬＡＤ和ＬＣＸ,特异性均较高。结论：潘生丁ＳＰＥＣＴ能显著提高冠心病的检出,有效估计病变心肌范围和病变冠状动脉     

Combined thallium 201/technetium 99m-labeled pyrophosphate tomography for identification of the “culprit” vessel in acute myocardial infarction

Background

Many previous investigations have used the presence of transient ischemic ²⁰¹Tl perfusion defect to localize coronary artery stenosis. This study reports the results of ²⁰¹Tl tomography alone and combined ²⁰¹Tl/^99mTc-labeled pyrophosphate (^99mTc PYP) tomography employed to identify the infarct-related vessel in patients with acute myocardial infarction (AMI).

Methods and Results

All short-axis images were evaluated by dividing each left ventricular slice into eight equal sectors. In addition, for combined ²⁰¹Tl/^99mTc PYP tomography, two sectors were added to evaluate involvement of the right ventricle. In a preevaluation phase of the study, the sectors were assigned to the supplying coronary arteries in 75 patients with single chronic myocardial infarction related to the left anterior descending coronary artery (LAD), left circumflex artery (LCX), or right coronary artery (RCA). In this pilot phase, ²⁰¹Tl tomograms were reviewed in conjunction with the angiographic data. This assignment was then tested prospectively in 117 patients with AMI. As confirmed by angiography, the AMI was related to the LAC, LCX, and RCA in 54, 17, and 46 patients, respectively. Sensitivity and specificity for ^99mTc PYP accumulation on combined ²⁰¹Tl/^99mTc PYP tomography were 98% a nd 100% for the LAD, 88% and 99% for the LCX, and 98% and 96% for the RCA, respectively. For ²⁰¹Tl tomography, sensitivity and specificity for identification of the culprit vessel were 94% and 89% for the LAD, 82% and 91% for the LCX, and 72% and 96% for the RCA, respectively.

Conclusion

This prospective study demonstrates that combined ²⁰¹Tl/^99mTc PYP tomography is highly accurate for identification of the infarct-related artery in AMI, even in patients with multivessel disease. Positive contrast visualization of myocardial necrosis in both the left and right ventricle allows for reliable differentiation between AMI related to the LCX or RCA territory. In comparison, for ²⁰¹Tl tomography the sensitivity to detect the culprit vessel, particularly the LCX and RCA, appears to be lower than for ²⁰¹Tl/^99mTc PYP imaging, particularly in patients with prior infarction or right dominant coronary artery.     

Dipyridamole technetium-99m-2-methoxy isobutyl isonitrile tomoscintigraphic imaging for identifying diseased coronary vessels: comparison with thallium-201 stress-rest study

A same-day double injection protocol employing 99mTc-methoxyisobutyl isonitrile (MIBI) and myocardial single-photon emission computed tomography (SPECT) for detecting coronary artery disease (CAD) was assessed in 30 patients. SPECT was performed 1 hr after a first injection (250 MBq) of 99mTc-MIBI, given after 0.56 mg/kg dipyridamole (DPD) infusion. Patients were then reinjected at rest (750 MBq) and were reimaged 1 hr later. Within 1 wk, all patients underwent a complete stress-rest SPECT thallium study. Of the 330 myocardial segments evaluated, 25 were judged ischemic by both techniques, while persistent defects were demonstrated in 50 and in 47 with 99mTc-MIBI and 201TI, respectively. Six regions were considered for diseased vessels identification. Sensitivity and specificity for CAD were 100% and 75%, respectively, for both 201TI and 99mTc-MIBI. Sensitivity for identification of diseased vessels by 201TI was 68% for LAD, 89% for RCA, and 80% for LCX as opposed to 75%, 89% and 80%, respectively, by 99mTc-MIBI. Specificity was 93% in both cases for LAD, 73% and 63% for RCA, and 53% and 46% for LCX.     

Diagnosis of coronary artery disease using thallium imaging: tomographic versus planar imaging

Coronary artery disease was evaluated with tomographic and planar thallium imaging in 31 subjects who had undergone coronary angiography for assessment of chest pain syndrome. Coronary arteriography revealed significant coronary artery disease in 17; and 14 had normal coronary arteries. The sensitivity and specificity for planar imaging was 71% and 79%, and that for tomography, 94% and 79% respectively. The sensitivity and specificity figures for individual coronary artery lesion detection for planar imaging were 87/83 for LAD, 33/100 for LCX and 50/86 for RCA respectively, and for tomography the figures were 87/87 for LAD, 33/95 for LCX and 90/76 for RCA respectively. The use of coronary arteriography as a gold standard was considered by assessing its interobserver variability, which was 16%. The interobserver variability for thallium imaging was 8% and 3% respectively for tomographic and planar acquisitions.     

Diagnostic accuracy of simultaneous acquisition of transmission and emission data with technetium-99m transmission source on thallium-201 myocardial SPECT

PURPOSE: This study evaluates not only the clinical usefulness but also the problems in attenuation correction for thallium-201 (Tl-201) myocardial SPECT by means of simultaneous transmission and emission data acquisition in the detection of coronary artery disease (CAD). METHODS: A three-detector SPECT system equipped with a Tc-99m line source and fan-beam collimators was used for simultaneous transmission and emission data acquisition for Tl-201 myocardial SPECT in 73 patients (18 patients for normal database and 55 patients for the evaluation of diagnostic accuracy). Attenuation-corrected (AC) images and non-attenuation-corrected (NC) images were reconstructed with an iterative maximum-likelihood estimation-corrected (ML-EM) algorithm. Both sets of images were reoriented into the short axis. Normal database polar maps were constructed from the AC and NC images for quantitative analysis. RESULTS: There was a significant difference in specificity between NC and AC images in the RCA territory and those in specificity and accuracy in the LCX territory. There was no significant difference in sensitivity found between NC and AC images in either territory, but sensitivity in both territories tended to decrease with attenuation correction. In the LAD territory, there were various changes in sensitivity and specificity observed with attenuation correction in cases with each quantitative criterion. CONCLUSIONS: Diagnostic performance of significant stenosis in the RCA and LCX territories quantitatively improved with attenuation correction because of an increase in specificity, but no significant improvement in diagnostic performance was obtained in the LAD territory with attenuation correction. We recommend combined interpretation of AC and NC images and careful evaluation of any SPECT image by means of transmission computed tomography.     

Impact of attenuation correction by simultaneous emission/transmission tomography on visual assessment of 201Tl myocardial perfusion images.

It has been shown in clinical studies that for subjects with a low likelihood of coronary artery disease (CAD), attenuation correction (AC) improves the specificity of defect detection in the inferior wall (right coronary artery [RCA] region). The aim of this study was to investigate the effect of AC on the visual interpretation of the RCA and anteroseptal (corresponding to the left anterior descending artery [LAD]) regions in CAD patients. METHODS: Fifty-six patients with suspected CAD underwent 20Tl stress/4 h-delayed imaging SPECT using a simultaneous 201Tl emission/99mTc transmission imaging protocol. Images were reconstructed using the maximum likelihood-expectation maximum algorithm without and with AC. The stress/4 h-delayed images were interpreted blindly for reversible or fixed defects in the RCA and LAD regions by three experienced physicians. Coronary angiography, electrocardiography and enzyme findings were used to establish diagnoses of ischemia or infarction, and receiver operating characteristic (ROC) analyses were performed. RESULTS: Statistical testing of ROC curve areas showed that defect detection performance improved with AC when compared with performance without AC in the RCA region. This was mainly the result of a systematic increase in specificity of 12% or more (for any observer and any type of defect) for a similar sensitivity (no definite change in sensitivity values). However, defect detection performance significantly decreased in the LAD territory with AC images (P < 0.05) because of a systematic decrease in sensitivity of 20% or more, with no consistent change in specificity. Similar trends were observed when reversible and fixed defects were considered separately. CONCLUSION: AC significantly affects the visual interpretation of 201Tl stress/4 h-delayed SPECT images. This study confirmed the increase in specificity obtained with AC in the RCA territory. However, in the population considered, the studied AC was deleterious for the LAD territory assessment.     

Segmental analysis of stress thallium myocardial emission tomography for localization of coronary artery disease

The value of stress thallium 201 myocardial emission computed tomography (ECT) in the assessment of coronary artery disease (CAD) was analyzed in 75 patients admitted for coronary arteriography. The ECT provided contiguous transaxial, short-axis, and long-axis sections of the myocardium and the myocardial images were divided into nine segments. The sensitivity and specificity in the diagnosis of CAD were 95% and 93%, respectively. Using selected segments, the ECT identified 97 of 111 (83%) major vessels involved: 89% for right coronary artery (RCA), 88% for left anterior descending (LAD), and 70% for left circumflex (LCx). Among the 75 cases, 35 underwent stress conventional planar imaging within 3 months. The planar imaging provided high sensitivity (90%) and specificity (100%) for the detection of CAD patients as well, but it showed lower sensitivity (57%, P<0.001) in identifying individual vessels involved: 55% for RCA (P<0.01), 70% for LAD, and 36% for LCx (P<0.05). Stress ECT detected vessel involvement more in two-vessel disease (85%) and three-vessel disease (78%) than the planar imaging (50%: P<0.05 and 44%: P<0.01, respectively). Thus, segmental analysis of stress ECT yielded as high sensitivity and specificity in the diagnosis of CAD as the planar imaging. This can improve sensitivity in identifying individual vessels involved in deep myocardial regions, especially in those with multivessel disease.     

Tc-99m tetrofosmin myocardial perfusion SPECT after dipyridamole combined with low-level exercise in the diagnosis of coronary artery disease

Tc-99m tetrofosmin is a lipophilic, cationic perfusion imaging agent that changes to Tl-201 in detecting coronary artery disease during exercise testing. The purpose of this study is to evaluate the usefulness of Tc-99m tetrofosmin dipyridamole stress imaging combined with low level exercise for the detection of coronary artery disease. We examined 42 patients and 10 normal volunteers who also underwent coronary angiography. A one-day protocol was used: in the stress study, 296 MBq of tetrofosmin was injected and in the rest study 888 MBq was injected. After intravenous administration of dipyridamole (0.142 mg/kg/min for 4 minutes), the patient was exercised on a bicycle ergometer for 3 min (25 Watts). Tetrofosmin was injected 2 minutes after dipyridamole infusion during the exercise. Single photon emission computed tomographic images were obtained 30 minutes after the tracer injection. Images were interpreted as abnormal in 36 of 42 patients with coronary artery disease, and normal in all of 10 normal volunteers. The overall sensitivity of detection of coronary artery disease was 83.3% and the normalcy rate was 100%. The diagnostic values for the detection of significant stenosis in the three major arteries were: LAD sensitivity 83%, specificity 92%; LCX sensitivity 47%, specificity 91%; RCA sensitivity 75%, specificity 83%. Of the 66 arteries with more than 50% stenosis, 48 arteries were correctly identified. Of the 36 with more than 70% stenosis, 31 were identified. Scintigraphic evidence of multivessel disease was found in only 9 patients (50%). A protocol of Tc-99m tetrofosmin SPECT combined with low level exercise after dipyridamole is therefore useful for the detection of the coronary artery disease.     

Detection of severe cornary heart disease with TI-201: comparison of resting single photon emission tomography with invasive arteriography

To investigate the application of TI-201 single photon emission computed tomography (SPECT) at rest in the confirmation of coronary heart disease (CHD), we studied 95 patients who had all undergone coronary angiography and cineventriculography. We separated three groups, patients with (a) prior myocardial infarction (MI) (n = 45), (b) no history of MI (n = 40), and (c) no abnormality of coronary angiogram (n = 23). The results of planar imaging with computer-assisted evaluation (scintimetry, SCM) and of SPECT with a three-plane reconstruction (transverse, sagittal, frontal) were compared with the invasive, arteriographic findings. SPECT yielded a higher sensitivity (93%) than SCM (68%) in the detection of defects in both infarcted and noninfarcted groups. The specificity was found to be almost equal in the two imaging modalities. A significant (p less than or equal to 0.01) increase in accuracy was found in SPECT in the assessment of the posterior wall (54% compared with 88%) as well as in the general detection of defects (68% compared with 88%). Applying the SPECT imaging technique increases both the diagnostic accuracy of TI-201 myocardial imaging and the anatomical association of CHD.     

腺苷负荷心肌灌注显像评价心肌血流供应异常的临床研究

目的 回顾性分析腺苷负荷/静息心肌灌注显像用于评价冠心病心肌血流供应异常的准确性和临床价值.方法 1858例临床确诊或可疑冠心病患者行常规标准程序两日法腺苷负荷/静息99Tcm-甲氧基异丁基异腈心肌灌注断层显像,由2位以上核医学科医师共同阅片定性分析图像.所有患者在显像前后1个月内行冠状动脉（简称冠脉）造影检查.方法间的一致性分析用Kappa检验,Kappa＞0.45为一致性较好.结果 1858例患者中,冠脉造影有1支及1支以上冠脉狭窄≥50%的患者957例,其中单支病变506例,双支病变256例,三支病变195例;共累及冠脉1603支,其中左前降支（LAD）765支、左回旋支（LCX）399支、右冠脉（RCA）439支.腺苷负荷/静息心肌灌注显像示心肌缺血或心肌梗死者1126例,与冠脉造影对照,其诊断冠心病的灵敏度为91.54%（876/957）,特异性为72.25%（651/901）,阳性预测值为77.80%（876/1126）,阴性预测值为88.93%（651/732）,2种方法一致性好（Kappa=0.641）.对LAD、LCX和RCA病变诊断的灵敏度分别为81.31%（622/765）,56.64%（226/399）和70.62%（310/439）;对单支、双支和三支冠脉病变的灵敏度分别为87.55%（443/506）,94.92%（243/256）和97.44%（190/195）.腺苷不良反应的发生率为84.12%（1563/1858）,无严重心脏事件发生.结论 腺苷负荷心肌灌注断层显像诊断冠心病有较高的灵敏度、特异性和准确性,对评价心肌血流供应异常有重要的临床价值.     

SPECT attenuation artifacts in normal and overweight persons: insights from a retrospective comparison of Rb-82 positron emission tomography and TI-201 SPECT myocardial perfusion imaging

PURPOSE: Myocardial perfusion imaging can be performed using SPECT or positron emission tomography (PET). SPECT has lower specificity than PET, largely as a result of attenuation artifacts; however, it is more widely available. The authors describe a study of the effect of sex and body weight on the incidence of SPECT attenuation artifacts using a retrospective comparison of TI-201 SPECT and Rb PET. METHODS: One hundred sixty-one persons (101 men, 60 women; 81 normal weight, 80 overweight) underwent TI-201 SPECT and Rb PET. The incidence of observed perfusion defects was studied in territories of the three major coronary arteries. SPECT and PET results were also compared with those of angiography in a subset of 75 patients. RESULTS: One hundred fourteen defects were reported on Rb PET compared with 176 defects with TI-201 SPECT. Excess TI-201 SPECT defects occurred in male and female, normal-weight and overweight persons. The average specificity was 64% for TI-201 SPECT and 84% for Rb PET, reflecting this difference. CONCLUSIONS: Attenuation artifacts in TI-201 SPECT occur frequently and are not confined to easily identifiable subgroups of patients. Therefore, measures to improve specificity of SPECT (e.g., prone or gated imaging) or alternative imaging techniques such as PET have potential advantages for everyone, not simply for obese patients and women with large breasts. In addition, awareness of the prevalence of SPECT attenuation artifacts, in both sexes and all weight categories, may contribute to improved accuracy of interpretation.     

Comparative localization of myocardial ischemia by exercise electrocardiography and myocardial perfusion SPECT

BACKGROUND: Prior angiographic study has shown that the patterns of ST-segment depression during exercise do not provide localizing information of the responsible coronary lesion. However, little is known regarding the ability of exercise-induced ST-segment displacement to localize myocardial perfusion defects. METHODS AND RESULTS: We studied 552 consecutive patients without prior myocardial infarction who had reversible perfusion defect in one vascular territory on rest 201Tl/exercise 99mTc-labeled sestamibi dual-isotope myocardial perfusion single photon emission computed tomography (SPECT) and ischemic ST depression or elevation during exercise. Of these, 192 patients had angiographically documented coronary artery disease (CAD). Two hundred thirty-two patients had maximal ST depression in anterior leads, 247 patients had maximal ST depression in inferior leads, and 45 patients had similar maximal ST depression in both anterior and inferior leads. Twenty-eight (5%) patients had ST elevation with absent Q waves. In patients with maximal ST depression in anterior leads, perfusion defects were found in the territory of the left anterior descending coronary artery (LAD) in 30%, in the territory of the right coronary artery (RCA) in 52%, and in the territory of the left circumflex coronary artery (LCX) in 18%. In patients with maximal ST depression in inferior leads, perfusion defects were found in RCA territory in 44%, in the LAD territory in 42%, and in the LCX territory in 14%. Compared with exercise ST depression, the less common finding of ST elevation did provide accurate localization of perfusion defects. When ST elevation was greatest in the anterior leads, 96% of patients had LAD territory defects. When ST elevation was most prominent in the inferior leads, 100% patients had RCA territory defects. Data of coronary angiograms demonstrated that myocardial perfusion SPECT correctly identified the most stenotic coronary disease for LAD (94%), LCX (72%), and RCA (75%). CONCLUSIONS: The findings of this study indicate that the site of maximal ST-segment depression does not identify the localization of myocardial perfusion defects. However, the less common finding of exercise-induced ST-segment elevation does predict localization of myocardial ischemia.     

变异型心绞痛与冠状动脉病变关系临床分析

目的 :探讨变异型心绞痛与冠状动脉病变的关系。方法 :临床观察 88例VA患者 ,均采用标准 18导联心电图或CM5/CMavF导联系统进行Holter监测 2 4小时 ,并行冠状动脉造影检查 ,明确VA发作时ST段抬高导联的分布特点、与冠状动脉病变的有无、病变范围及程度的关系。结果 :88例患者经冠状动脉造影显示 :冠状动脉狭窄 <5 0 %者占 3 9 8% ,冠状动脉狭窄在 5 0 %～ 10 0 %者占 61 2 %。而冠状动脉造影正常的VA患者发作时痉挛部位在右冠状动脉 (RCA)的占 82 9% ,与在左前降支 (LAD)的占 11 4% ,在左回旋支 (LCX)的占 5 7%比 (P <0 0 0 1) ;存在冠状动脉固定性狭窄的VA患者发作时痉挛部位在LAD的占5 4 7% ,与痉挛部位在RCA的占 2 2 6% ,在LCX的占 2 2 6%比 (P <0 0 1)。结论 :在冠状动脉无明显病变的VA患者中 ,RCA痉挛的发生率明显高于LAD ;而对于存在冠状动脉固定性狭窄的VA患者 ,冠状动脉痉挛的发生率以LAD最高。     

Multi-center study for the evaluation of clinical usefulness of attenuation and scatter correction on 201Tl myocardial SPECT

The aim of this study was to evaluate the clinical usefulness of attenuation and scatter correction (AC, SC) on a 201Tl myocardial single-photon emission computed tomography (201Tl SPECT) as a multi-center trial. With a dual-detecter and a triple-detector SPECT systems with a 99mTc transmission source, simultaneous transmission/emission tomography (TCT/ECT) was performed on 38 patients with angiographically coronary heart disease (CHD) and 26 patients without evidence of CHD. Stress and delayed attenuation and scatter corrected images (SAC) and uncorrected images (NC) were reconstructed. On NC images of normal cases, influence of attenuation was greater in male than female. In comparison of 201Tl distribution between male and female, significant decrease in 201Tl activity was observed in the inferoposterior wall in male and that was observed in the anterobasal wall of the left myocardium in female. Such a difference in 201Tl distribution between male and female disappeared on SAC images. On the diagnostic performance for the identification of CHD, SAC images demonstrated improved specificity and accuracy values in the right coronary arterial territory (RCA) with visual analysis statistically. Sensitivity value in the RCA was also improved, but it was not statistically significant. Sensitivity value in the left circumflex arterial territory (LCX) increased without decrease in specificity value on SAC images. In the left anterior descending arterial territory (LAD), sensitivity value increased on SAC images. Although specificity value decreased on SAC images in LAD territory, it was not statistically significant. The difference in 201Tl distribution between male and female is improved in normal cases by attenuation and scatter correction on 201Tl myocardial SPECT. Diagnostic performance of CHD is also improved by attenuation and scatter correction, especially in territories of which specificity in assessing the absence of disease have been suboptimal. In conclusion, attenuation and scatter correction on 201Tl myocardial SPECT is considered to be clinically useful.     

静息心肌灌注显像判断梗塞相关动脉的作用

目的　评价静息心肌显像的缺血缺损部位对于判断梗塞相关动脉 (IRA)的价值。方法对 44例心肌梗死患者进行99Tcm 甲氧基异丁基异腈 (MIBI)静息心肌断层显像和冠状动脉造影(CAG)。结果　CAG提示IRA 44支 ,其中左前降支 (LAD) 2 7支 ,左旋支 (LCX) 9支 ,右冠脉 (RCA) 8支。当IRA是LAD时出现间壁受累 ,IRA是LCX时出现侧壁受累和IRA是RCA时表现下后壁受累的意义较大 (χ2 =8.98和 8.96 ,P均 <0 .0 5 ;χ2 =43.82 ,P <0 .0 0 5 )。前壁、心尖部、间壁和广泛前壁稀疏缺损对于判断IRA LAD的灵敏度较高 ,分别是 89% ,86 % ,80 %和 89% ;特异性以间壁最高 ,达 80 % ;侧壁和后侧壁判断IRA LCX的灵敏度和特异性分别是 75 % ,6 7%和 85 % ,83% ;下后壁病变判断IRA RCA的灵敏度和特异性分别是 71%和 91%。结论　心肌灌注显像对于判断心肌梗死的IRA有一定价值     

Interpolating scan and oblique-angle tomograms in myocardial PET using nitrogen-13 ammonia

The effect of low sensitivity areas or gaps between adjacent slices of the multislice positron emission tomography on detection of myocardial perfusion abnormality with 13NH3 was evaluated segmentally in 36 patients with coronary artery disease at rest or during exercise. The detectability of the defects in RCA or LAD region was 80% in single-position scans in stress studies. The false-negative defects were located mainly in the inferior wall, apicoinferior wall, or high anterior wall. When the patients were moved half the slice interval to perform the interpolating scan, and the two sets of images were interlaced with each other, the detectability increased to 88%. The interpolating scan also allowed reconstruction of long-axis and short-axis tomograms in high quality, which further improved the detectability of perfusion defects (100% for RCA or LAD and 75% for LCX lesion) and helped in understanding the anatomic relationships to the coronary artery territories.     

Clinical evaluation of 99Tcm-MIBI SPECT in the assessment of coronary artery disease.

To evaluate the clinical efficacy of 99Tcm-MIBI myocardial tomography for detecting coronary artery disease (CAD) 115 consecutive patients who underwent both 99Tcm-MIBI single photon emission computed tomography (SPECT) and coronary arteriography were studied. Thirty-three patients without and 82 with significant coronary artery disease were documented by coronary arteriography. The overall sensitivity and specificity of 99Tcm-MIBI SPECT for detecting coronary artery disease were 96 and 87.9%, respectively. The sensitivity for identifying patients with CAD without myocardial infarction was 88%. The sensitivity of 99Tcm-MIBI SPECT for detecting individual coronary artery lesions was 86% for left anterior descending artery (LAD), 69% for left circumflex artery (Lcx) and 86% for right coronary artery (RCA), lesions respectively. In conclusion, 99Tcm-MIBI SPECT provides a reliable method for detecting CAD.     

Thallium-201 single-photon emission CT versus CT for the detection of recurrent squamous cell carcinoma of the head and neck.

BACKGROUND AND PURPOSE: Thallium-201 single-photon emission computed tomography (SPECT) can be used to detect primary squamous cell carcinoma (SCCA) of the head and neck. Nevertheless, there have very few studies performed to evaluate the ability of thallium-201 to depict recurrent SCCA. The purpose of this study was to compare the ability of thallium-201 SPECT with CT to enable detection of recurrent SCCA of the upper aerodigestive tract. METHODS: Thirty-three patients with a history of previously treated SCCA of the extracranial head and neck underwent thallium-201 SPECT imaging and contrast-enhanced CT. A neuroradiologist and nuclear medicine physician with knowledge of the primary site evaluated all thallium-201 studies for abnormal radiotracer uptake at the primary site. These results were correlated with histologic findings and clinical follow-up in all patients. All patients were followed up for a minimum of 2 years after completion of treatment. The McNemar test was used to determine statistical significance. RESULTS: The diagnostic accuracy of thallium-201 SPECT was as follows: sensitivity, 88%; specificity, 94%; positive predictive value, 93%; and negative predictive value, 89%. The diagnostic accuracy of CT was as follows: sensitivity, 100%; specificity, 24%; positive predictive value, 55%; and negative predictive value, 100%. The diagnostic accuracy of thallium was superior to CT (P = .01). CONCLUSION: Thallium-201 SPECT is superior to CT for differentiating recurrent tumor from post-treatment changes and may complement CT in the evaluation of previously treated SCCA of the extracranial head and neck.     

Coronary angiography and thallium-201 single photon emission computed tomography in single vessel coronary artery disease

Polar presentations of selective coronary angiography and myocardial 201T1 SPECT were compared in 49 patients with single vessel disease. Twenty-six lesions were located in LAD, 8 in LCX and 15 in RCA. Perfusion defects were found within the supply area of 44 stenotic and 20 non-stenotic arteries. 201T1 SPECT detected coronary disease in 45 patients (92%) and the obstructed artery in 44 (90%). Single vessel disease was correctly indicated in 28 patients (57%) where the perfusion defects did not extend significantly outside the area supplied by the stenotic artery. Extensive perfusion defects could be explained by 'collateral steal', myocardial disease, LV aneurysm or spasm in 9 patients (18%). The absence of perfusion defect related to the stenotic artery could be explained by a moderate degree of stenosis or well developed collateral vessels in 5 patients (10%). Proximal LAD lesions resulted in larger perfusion defects than distal.     

A new method to evaluate ischemic heart disease: Combined use of rest thallium-201 myocardial SPECT and Tc-99m exercise tetrofosmin first pass and myocardial SPECT

We developed a new diagnostic method for simultaneously evaluating myocardial ischemia, myocardial viability and ventricular function in less than 90 minutes by combined use of rest thallium-201 (Tl) SPECT and exercise Tc-99m tetrofosmin (TF) first pass and SPECT. The subjects were 9 healthy controls, 19 angina pectoris patients, and 19 old myocardial infarction patients, in all of whom coronary angiography had been performed. Rest Tl myocardial SPECT was performed first, and was followed by exercise TF myocardial SPECT. We also performed first pass radionuclide angiography by TF during maximum exercise on a bicycle ergometer to assess the left ventricular ejection fraction (LVEF). The total examination time was less than 90 minutes. SPECT diagnosis was performed by semi-quantitative analysis. LVEF below 55% was regarded as abnormal. In the patients with angina pectoris, analysis according to the coronary artery showed that the diagnostic accuracy of SPECT was 85.0% for ischemia in the region of the left anterior descending branch (LAD), 87.5% for the left circumflex branch (LCX) and 77.8% for the right coronary artery (RCA). The accuracy of diagnosis for angina pectoris was 82.1%, as determined by SPECT alone, and rose to 89.3% when the LVEF levels were also taken into consideration. In the patients with old myocardial infarction, the diagnostic accuracy of SPECT was 84.2% for the LAD, 92.3% for the LCX and 85.0% for the RCA. Analysis by patients showed that the accuracy of diagnosis for myocardial infarction was 85.7%, as determined by SPECT alone. The diagnostic accuracy, however, rose to 89.3% when the LVEF levels also were taken into consideration. In conclusion, it was demonstrated that this combined diagnostic method was highly reliable for evaluating ischemic heart disease within a short time.