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Atrial pacing and thallium-201 scintigraphy in patients with chest pain: correlation with coronary anatomy.

Atrial pacing and thallium-201 scintigraphy were performed in 72 patients referred for evaluation of chest pain. Coronary artery disease (CAD) was present in 63 patients, as documented by cardiac catheterization performed at the same time or within 2 months of atrial pacing. Nine patients had no or insignificant (less than 50% stenosis) CAD. The sensitivity of pacing-induced angina for CAD was 51%, and was 49% for ST depression. Specificities were 89% and 78%, respectively. A reversible perfusion defect was seen in 54% of patients with CAD (specificity 89%), and a fixed defect in 29% (specificity 100%). The sensitivity of an abnormal thallium-201 scan (one or more reversible or fixed defects) was 79% (p less than 0.05 compared to angina or ST depression). Combined sensitivity of ST depression and/or an abnormal thallium-201 scan was 87%. There were no significant changes in any of these sensitivities as the number of vessels with CAD increased. Thallium-201 scintigraphy correctly identified 11 of 19 (58%) patients with single-vessel disease as having CAD in only one vessel, but underestimated the extent of disease in all but a few patients with multivessel disease. The sensitivity of perfusion imaging to identify lesions in specific vessels ranged from 27% (circumflex) to 57% (right coronary artery). Specificities were 100% for circumflex, 78% for anterior descending, and 83% for right coronary artery lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Dipyridamole thallium imaging may not be a reliable screening test for coronary artery disease in patients undergoing vascular surgery.

Dipyridamole thallium imaging has been proposed for cardiac risk stratification in patients undergoing peripheral vascular surgery. The purpose of this study was to define the benefit of this investigation in routine preoperative evaluation of these patients. The outcome of 86 patients undergoing vascular surgery procedures was examined in light of preoperative clinical assessment and dipyridamole SPECT thallium imaging (DST). Fifty-one patients (59%) were considered at high risk on clinical grounds, and 22 patients (26%) had perfusion defects. Ten patients suffered a perioperative coronary event, including unstable angina, myocardial infarction, or cardiac death. Seven of the patients with such events were among the 51 clinically high-risk subjects (14%). Three perioperative events occurred in the group of 19 patients with positive DST images who underwent surgery (16%), but the DST test failed to identify 7 patients who suffered coronary events. The frequency of abnormal thallium imaging was similar to the prevalence of angiographically significant coronary disease reported previously at this center, but considerably less than the rate of abnormal thallium imaging in past studies of vascular surgery patients. The application of the test to a low to moderate risk population is probably responsible for its lower predictive accuracy for coronary events. DST is not an ideal routine noninvasive technique for risk stratification in patients undergoing vascular surgery.

Aged↗

Long-term prognostic value of a normal dipyridamole thallium-201 perfusion scan.

In a 4-year period, 84 patients who were referred for a dipyridamole thallium-201 stress test to rule out significant coronary artery disease had normal scans. A dipyridamole study was recommended instead of exercise because of arthritis, severe obesity, peripheral vascular disease, pulmonary disease, other chronic illnesses, or combinations of these problems. All patients had three-view (i.e., anterior, shallow left anterior oblique, and steep left anterior oblique) planar thallium-201 imaging 10 minutes and 3.5 hours after administration of 0.6 mg/kg of intravenous dipyridamole. The patients were followed for 42 +/- 13 (range 1-58) months to document the cardiac event rate. Of the 84 patients with normal results, 14 died during the follow-up period from noncardiac causes. Three other patients died 29-51 months after the test due to an acute myocardial infarction, a probable acute myocardial infarction, and sudden cardiac death, respectively. Of the survivors, 5 suffered an acute myocardial infarction 28-50 months after the dipyridamole thallium scan and 1 had coronary artery bypass grafting due to increasing angina pectoris 58 months after the scan (overall cardiac event rate of 0.4% per year). Of the remaining 61 patients, 39 (64%) were asymptomatic, 20 (33%) had the same symptoms they had at the time of testing without significant deterioration, while 2 patients (3%) had deterioration of their chest pains but no cardiac complication. Thus, in this group of patients, a normal dipyridamole thallium-201 perfusion scan predicted a good cardiovascular outcome for at least 24 months following the test.

Adult↗

Distribution of nerve conduction velocities in acute thallium poisoning.

To assess the effects of thallium on the conduction velocities of faster and slower nerve fibers, the distribution of conduction velocities in sensory fibers of the median nerve was examined in a patient with acute thallium poisoning 2 and 11 months after the onset of symptoms. In the first examination, the patient showed evidence of a distal sensorimotor neuropathy and had an elevated urinary thallium concentration (3.5 mg/L); the conduction velocities of faster fibers were below the normal lower limit, whereas those of slower fibers were within normal limits. At the second examination, the conduction velocities of all faster and slower fibers increased and were within normal limits; clinical signs and symptoms of neuropathy almost disappeared. It is concluded that the conduction velocities of faster fibers significantly decrease in an early stage of acute thallium poisoning and recover following recuperation from the poisoning; those of slower fibers are minimally affected and then improve.

Adult↗

Electrophysiologic investigation of thallium poisoning.

Electrophysiologic findings in thallium intoxication are usually untimely, limited in extent, and often uninformative. This report documents serial conduction and electromyographic findings in a case of thallium poisoning, beginning 10 days after symptom onset and ending 24 months later. Initially, the plantar nerves in the foot demonstrated profound axonal loss while the sural and peroneal nerves were essentially normal. The latter two nerves subsequently underwent axonal loss. Two years were required for the sural and peroneal nerves to display recovery. At 24 months, the plantar nerves continue to remain absent. A primarily distal axonopathy, significantly worse in the lower than upper extremities and requiring more than 2 years for recovery, now documents what was previously speculated: the electrophysiologic course of thallium intoxication. Additionally, this case emphasizes the need to examine the plantar nerves of the foot to avoid missing distal axonopathies during the early course of the disease process. The clinical course and pathophysiology of thallium poisoning are also reviewed.

Axons↗

The detection of coronary artery disease: a comparison of exercise thallium imaging and exercise equilibrium radionuclide ventriculography.

This study compared the accuracy of rest and exercise gated equilibrium technetium ventriculography with exercise thallium imaging in 50 consecutive male patients undergoing routine coronary angiography for the evaluation of chest pain. No patients were excluded on the basis of prior myocardial infarction, nature of angiographically defined coronary disease or symptoms. Antianginal therapy was continued in all patients. Eight patients had normal coronary arteries, 9 had single vessel, disease, 20 had double vessel disease and 13 had triple vessel disease. Sixteen patients had previously documented myocardial infarction. Using exercise radionuclide ventriculography, 34 patients with coronary disease were detected resulting in a sensitivity of 81%; 6 patients with normal coronary arteries had normal scans, a specificity of 75%, with a predictive accuracy of 80%. In comparison, thallium imaging detected 42 patients with coronary disease resulting in a sensitivity of 100%. Six patients with normal coronary arteries had normal thallium images resulting in a specificity of 75% and a predictive accuracy of 96%. These results suggest that exercise thallium imaging is a more accurate investigation than exercise equilibrium radio-nuclide ventriculography and is the investigation of choice in the noninvasive detection of coronary artery disease.

Adult↗

The use of thallium-201 in the preoperative detection of breast cancer: an adjunct to mammography and ultrasonography.

Thallium-201 breast scans were performed preoperatively in 72 female patients with breast abnormalities detected by mammography and/or ultrasonography (7.5-13 MHz), in order to differentiate benign from malignant breast disease. Informed consent was obtained from each patient. Scintigraphy consisted of anterior and oblique planar images of the affected breast and axilla at 10 min and 3 h following the injection of 201Tl chloride (110 MBq). All 201Tl scans were interpreted without prior knowledge of surgery data. Pathological features of breast malignancies, such as tumour size, axillary lymph node metastases, tumour grading, lymphatic vascular channel invasion and receptor status, were analysed for their association with 201Tl uptake by tumour cells. A total of 76 breast lesions were assessed in the study. On final histological diagnosis, there were 56 malignant tumours, 14 benign nodules (9 fibroadenomas, two cases of adenosis, two cases of focal fibrosis and one case of epitheliosis) and six atypical lesions (atypical ductal or lobular hyperplasia). Thallium scintigraphy was shown to have high accuracy (92%) in detecting breast cancer, better than mammography (74%) and ultrasonography (84%). Almost all (51/56) breast cancers showed greater 201Tl activity than surrounding normal breast tissue while there was no significant increase in 201Tl activity above background in all but one (19/20) case of non-malignant disease. 201Tl activity within breast tumours, calculated as tumour/background (T/B) ratio, ranged between 1.2 and 2.5 with a mean value of 1.45. In our experience the concentration of thallium in the breast cancer seems to be primarily dependent on vascularity and tumour size rather than tumour grading, lymphatic/vascular invasion or receptor status. 201Tl scan sensitivity was 97% for malignant lesions larger than 1.5 cm (n = 35) and 80% for lesions of 1.5 cm or less (n = 21); however, five of the eight breast cancers smaller than 1.0 cm were also detectable by 201Tl scintigraphy, compared with five out of seven by mammography. Thallium scintigraphy would not be useful in evaluating the axilla for lymph node metastases (sensitivity 27%, specificity 77%).

Adult↗

Quantitative myocardial thallium single-photon emission computed tomography in normal women: demonstration of age-related differences.

The aim of this study is the development of a database of normal women for quantitative analysis of exercise and reinjection myocardial single-photon emission computed tomography (SPET). We studied 101 subjects (40 males and 61 females) with less than 5% likelihood of coronary artery disease. All patients underwent stress and rest thallium-201 myocardial SPET. Myocardial stress was induced by bicycle exercise test (n=51), dipyridamole infusion (n=27) or a combined test (n=23). Multivariate ANOVA showed that the type of stress did not influence the percentage of thallium uptake for each region. Significant differences between men and women were found for the percentage of uptake in the inferior and the anterior wall. The most original finding of this study is the correlation between age and thallium uptake in the three regions of the anterior wall, showing an increase in measured thallium uptake with age for women. Consequently, two groups of women, those under and those over 55 years old, were separated, with a significantly lower tracer uptake in the anterior wall in the younger age group. These results may suggest that the commonly described breast tissue attenuation is due not only to breast volume or morphology but also to breast density. This emphasizes the need for two different databases for myocardial SPET quantitative analysis in the female population. Awareness of this fact should allow avoidance of any underestimation of possible anterior wall ischaemia in women aged more than 55 years.

Adult↗

The impact of clinical data on interpretation of thallium scintigrams.

BACKGROUND: The availability of clinical information often influences the interpretation of diagnostic imaging information. METHODS AND RESULTS: In this study we examined the impact of such data on interpretation of exercise thallium scans and the differences in analysis of such information between radiologists and clinicians. Two hundred thirty-seven exercise tolerance test-thallium scans (122 in patients with suspected coronary disease and 115 in patients with documented coronary disease) were read prospectively, first without and then with the knowledge of clinical information. Test scores, the readers' and clinicians' interpretations of historic data, and any changes in readings or interpretation of scintigraphic data were recorded. We found that the addition of clinical information resulted in changes in interpretation of 63 test results (27%), 20 (8%) of them major. Furthermore, clinical data significantly affected final test scores in 26 patients (11%), potentially affecting clinical management in this group. The changes in test scores were triggered predominantly by differences in interpretation of perfusion abnormalities rather than thallium lung uptake or left ventricular dilation with exercise. The impact of clinical data on overall test scores was greater in patients with suspected than documented coronary disease (p < 0.05). There was good agreement in assessment of clinical information between scan readers and a clinician in tests done in patients with suspected coronary artery disease but not in patients with known coronary disease. CONCLUSIONS: We conclude that clinical information has major influences on the interpretation of thallium scans, and interpretation of data can vary significantly between cardiologists and radiologists depending on the nature of the clinical data.

Coronary Disease↗

Reduced variability of interpretation and improved image quality with a technetium 99m myocardial perfusion agent: comparison of thallium 201 and technetium 99m-labeled tetrofosmin.

BACKGROUND: The purpose of this study was to determine the relative image quality and interobserver variability among four readers for 201Tl and 99mTc-labeled tetrofosmin myocardial perfusion images. 99mTc-labeled perfusion agents, with near-optimal physical characteristics for gamma camera imaging, may allow for superior image quality and improved consistency of interpretation. However, most studies to date have demonstrated only similarity in the diagnostic accuracy between technetium agents and thallium. Tetrofosmin is a recently developed 99mTc-labeled agent that has shown promising results in early clinical trials. METHODS AND RESULTS: A multicenter, open-label trial was performed during which treadmill exercise thallium and tetrofosmin scintigraphy was performed within a 2-week period of each other in 216 subjects. Image quality was evaluated subjectively and scans were interpreted in a blinded, independent fashion by four readers. Perfusion abnormalities were graded as consistent with ischemia, infarction, or mixed and were described both globally and regionally. Interobserver variability was assessed by use of the kappa statistic, and receiver-operator curves were compared for each observer for the diagnostic accuracy of each agent. More tetrofosmin images were of excellent quality than with thallium (52% vs 28%; p < 0.05), and when differences in quality were noted between the agents, tetrofosmin was more often superior (p < 0.0001). The interobserver variability was lower with tetrofosmin scintigraphy because generally higher kappa values were noted, especially in the lateral wall. Higher receiver-operator curve areas indicative of improved diagnostic accuracy were noted among the four readers for tetrofosmin in 80% of vascular territories. CONCLUSIONS: 99mTc-labeled tetrofosmin scintigraphy yields images of improved quality compared with thallium, and there is an overall improvement in the consistency of image analysis associated with the use of tetrofosmin.

Coronary Disease↗

Comparison of the treadmill exercise score and single-photon emission computed tomographic thallium imaging in risk assessment.

BACKGROUND: This study compared the prognostic value of exercise single-photon emission computed tomographic (SPECT) thallium imaging with that of treadmill exercise score in medically treated patients with coronary artery disease (CAD). METHODS AND RESULTS: The treadmill exercise score was derived from exercise duration, degree of ST segment depression, and the treadmill anginal index. There were 121 patients with no CAD and 316 patients with angiographically defined CAD (> or = 50% diameter stenosis of one or more vessels). During a mean follow-up of 29 months, there were 35 cardiac deaths or nonfatal myocardial infarctions. Multivariate Cox survival analysis showed the extent of thallium imaging abnormality and CAD to be independent predictors of prognosis. On the other hand, the treadmill exercise score was not a significant predictor even on univariate analysis. The results of thallium uptake were the strongest independent predictors of prognosis and in addition provided incremental prognostic power to coronary angiography (chi 2 = 29 for SPECT, 27 for coronary angiography, and 37 for both). CONCLUSIONS: Thus exercise SPECT thallium imaging is significantly better than the treadmill exercise score in risk assessment. The size of the perfusion abnormality is an important predicator of prognosis.

Adult↗

Positive gallium-67 and thallium-201 scans in thymic rebound after chemotherapy for lymphoma.

It is a diagnostic problem to distinguish thymic rebound or rebound thymic hyperplasia from thymic malignancy, but it is frequently made more difficult because most patients have had previous malignancies. Recently we evaluated a six-year-old girl with thymic rebound after chemotherapy for lymphoma, by both gallium-67 and thallium-201 scans. On gallium-67 scan, intensive uptake was seen in the anterior mediastinum. CT revealed a triangular-shaped, homogeneous mass in the anterior mediastinum. On early scan of thallium-201 study, slight accumulation was seen in the anterior mediastinum and was enhanced in delayed scans. Considering the clinical state and imaging results, thymic rebound after chemotherapy was the most likely diagnosis, and follow-up observation was done without therapy. During the course, there were no signs of relapse. Some reports have described both positive and negative thallium-201 accumulation in thymic rebound. Although more experience with similar cases is necessary, it is likely that thallium-201 also tends to accumulate in thymic rebound as well as gallium-67.

Antineoplastic Agents↗

Identification of asynergic but viable myocardium in patients with chronic coronary artery disease by gated blood pool scintigraphy during isosorbide dinitrate and low-dose dobutamine infusion: comparison with thallium-201 scintigraphy with reinjection.

To evaluate the ability of low-dose dobutamine and isosorbite dinitrate (ISDN) gated blood pool scintigraphy (GBPS) and thallium SPECT with reinjection to identify viability in asynergic myocardium, both procedures were performed in 38 consecutive patients with chronic coronary artery disease and left ventricular dysfunction. Twenty-two of the 38 patients with successful revascularization were analyzed. GBPS was performed at the baseline and during continuous infusion of low dose dobutamine (5 micrograms/kg/min) and ISDN (2 micrograms/kg/min). Cine mode GBPS wall motion was scored from normal (0) to dyskinesis (4) semiquantitatively. Forty-seven of 110 segments with severe asynergy at the baseline were analyzed. Viability determined by GBPS was defined as wall motion score improvement by more than 1 grade. Thallium viability was defined as the segment with redistribution or fill in with severe initial perfusion defect. GBPS was 76.7% sensitive and 70.6% specific for predicting post vascularization wall motion improvement (p < 0.005). Of 47 segments with severe asynergy, concordance of judgement was obtained in 40 segments (85.1%), and reversibility was correctly diagnosed in 34 of 40 patients (85.0%), but thallium with reinjection correctly identified tissue viability in 6 of 7 segments with discordance between 2 studies. These data suggest that most cases of reversible asynergy (hibernating myocardium) respond to ISDN and dobutamine, suggesting the possibility of predicting improvement by revascularization, although some underestimation of tissue viability remained to be resolved. Thallium with reinjection is superior to low-dose dobutamine + ISDN GBPS for the assessment of myocardial viability.

Adult↗

Sodium bicarbonate-augmented stress thallium myocardial scintigraphy.

It is well known that sodium bicarbonate in pharmacological doses induces transient alkalosis, causing intracellular transport of serum potassium. The aims of this study were (a) to investigate whether, in humans, myocardial thallium-201 uptake can be augmented by pretreatment with a single bolus of sodium bicarbonate at a pharmacological dose, (b) to verify general safety aspects of the intervention and (c) to evaluate the clinical implications of augmentation of (201)Tl uptake, if any. Routine exercise myocardial scintigraphy was performed twice in eight adult volunteers (five normal and three abnormal), once without intervention and the second time (within a week) following intravenous administration of sodium bicarbonate (88 mEq in 50 ml) as a slow bolus 1 h prior to the injection of (201)Tl. Conventional myocardial thallium study was compared with sodium bicarbonate interventional myocardial scintigraphy with respect to myocardial uptake (counts per minute per mCi injected dose), washout patterns in normal and abnormal myocardial segments, and overall clinical interpretation based on planar and single-photon emission tomographic (SPET) images. All patients remained asymptomatic after the intervention. A mean increase of 53% in myocardial uptake of thallium was noted in post-exercise acquisitions after the intervention, confirming uptake of the tracer via the potassium-hydrogen pump and its augmentation by transient alkalosis. The washout pattern remained unchanged. The visual quality of planar and SPET images improved significantly after the intervention. Out of the five abnormal myocardial segments identified in three cases, four showed significant filling-in after the intervention, causing the diagnosis to be upgraded from "partial scar" to "ischaemia", or from "ischaemia" to "normal". The overall scan impression changed in two out of three such cases. Sodium bicarbonate augmentation may have significant implications for stress-thallium scintigraphy and may be a new parameter for defining myocardial viability.

Adult↗

Motion detection and correction using multi-rotation 180 degrees single-photon emission tomography for thallium myocardial imaging.

Patient and organ motion is a potentially limiting factor in gamma camera single-photon emission tomography (SPET) imaging, as highlighted in stress thallium myocardial SPET, where the heart may exhibit a systematic axial motion (cardiac creep) following stress. Multi-rotation SPET has previously been described as a means of obtaining better raw data for motion detection and correction. This study describes the validation of a computerised motion detection algorithm applied to multi-rotation SPET, and reports measured motions in thallium myocardial stress SPET studies from a single-headed gamma camera. Forty-two patients underwent pharmacological stress (dipyridamole) with leg raising, with injection of 75 MBq thallium-201 and imaging after a 10-min delay to detect or evaluate coronary artery disease. Multi-rotation gamma camera SPET was performed with a single-headed gamma camera, with five sequential rapid (4.5 min) continuous SPET mode rotations over 180 degrees. A one-dimensional cross-correlation alignment technique was applied to the projection images to perform motion detection and correction in the axial direction prior to combining the five data sets for tomographic reconstruction. Validation of the cross-correlation alignment analysis was carried out by performing imaging with measured whole-body axial motions in nine subjects, and by reproducibility measurements on multi-rotation data sets. The effect of the applied motion correction was evaluated by calculating mean differences between image pairs before and after shifting, and the general reliability of the automatic motion detection was checked to within one pixel by visual assessment of 160 image pairs. Validation measurements of the cross-correlation technique gave a mean absolute error of 1.5+/-0.4 mm (0.24+/-0.06pixels) with a maximum error of 3.7 mm (0.6 pixels). In 40 subjects undergoing pharmacological stress 201Tl myocardial SPET imaging, the mean cardiac axial creep movement was calculated as 3.1+/-0.7 mm (0. 49+/-0.11 pixels), with 13 out of 40 (32%) having a calculated motion of 1 pixel (6.3 mm) or more. The automatic image shift was visually judged to be within 1 pixel in all 160 image pair analyses, and the mean pixel value difference between image pairs was reduced following image shifting. It is concluded that multi-rotation 180 degrees SPET imaging provides raw data which allow objective and accurate motion detection of cardiac motion in thallium stress myocardial imaging, whilst the one-dimensional cross-correlation technique demonstrates adequate accuracy and reliability to be applied as an automatic motion screening technique on these data.

Dipyridamole↗

Reconstruction of a case of thallium poisoning using LA-ICP-SFMS.

The unique capabilities of laser ablation in combination with inductively coupled plasma sector field mass spectrometry (LA-ICP-SFMS) were employed to reconstruct details of a homicide by thallium poisoning, which took place 38 years ago in Austria. Thallium was determined in several human bone samples after acid digestion in a microwave oven. The ICP-SFMS results showed that the thallium concentration in the victim's bones was in the range 1.07-2.63 microg g(-1), which is up to 170 times higher compared to concentrations found in bones of persons who have died due to natural causes. The results were in accordance with the values obtained by graphite furnace atomic absorption spectrometry (GF-AAS). Laser ablation ICP-SFMS was applied to assess the time interval between the victim's poisoning and death. Several line scans with a laser spot size of 50 mum were performed on a thumbnail of the poisoned person and on a reference thumbnail by laser ablation ICP-SFMS. Thallium peaks were detected on the nail of the victim at a distance of 2.5 mm from the younger edge of the nail.

Aged↗

Decrease in thallium-201 image defect size after permanent coronary occlusion.

In the 24 hours after coronary occlusion, some defects on thallium-201 images decrease in size. This study examined the mechanism of the decrease in defect size in dogs with experimental coronary occlusion. The left anterior descending coronary artery was permanently occluded in chronically instrumented awake dogs. Myocardial blood flow was measured with radioactive microspheres immediately before occlusion, 30 minutes, and 24 hours after occlusion. Thallium-201 was injected and imaging was performed 2 to 6 days before occlusion, 30 minutes, and 24 hours after occlusion. Two dogs, in which less than 1% of the left ventricle was infarcted, had no defects on the 30-minute postocclusion images. In four dogs the thallium-201 images did not change appreciably over 24 hours (group 1), while in three dogs the image defect size decreased (group 2). In groups 1 and 2 respectively the percent increase in blood flow to the hypoperfused area was: subendocardium 9 +/- 7% vs 31 +/- 15%; subepicardium 26 +/- 6% vs 47 +/- 2% (p less than 0.05). Therefore a decrease in the size of thallium-201 image defects occurred if a sufficient increase in collateral flow to the hypoperfused area took place in the first 24 hours after coronary occlusion. The defects appeared to decrease in size even in the absence of a detectable change in the lateral borders of the hypoperfused area.

Animals↗

The cardiokymography exercise test compared to the thallium-201 perfusion exercise test in the diagnosis of coronary artery disease.

To determine the usefulness of exercise cardiokymography (CKG) compared to thallium-201 perfusion scanning in the diagnosis of coronary artery disease (CAD), 179 patients with a mean age of 54 +/- 10 years (73% men) were studied. Previously documented CAD was present in 73 patients (41%); 13 (7%) were asymptomatic and 93 (53%) had chest pain syndrome. Exercise stress testing, CKG, and thallium-201 perfusion scanning were independently correlated with coronary angiographic data. Treadmill exercise stress test alone without CKG had a sensitivity of 68% and specificity of 62%. CKG showed a sensitivity of 76% and a specificity of 90%, and easily interpreted cardiokymograms were obtained in 78% of patients studied. Thallium-201 scans had a sensitivity of 79% and a specificity of 88%. However, when the CKG and treadmill exercise test results were concordant (both positive or both negative), the CKG exercise test had a sensitivity of 87% and specificity of 100%. Thus, when the CKG and exercise test results are concordant, the sensitivity and specificity are equal to or better than thallium-201 perfusion scanning for the prediction of CAD. Since CKG is an inexpensive and noninvasive test, its adjunctive use with routine exercise stress testing may be of great value.

Adolescent↗