Measurement of Perfusion of Pulmonary Nodules by Electron Beam Tomography

PURPOSE: To investigate the perfusion of pulmonary nodules and the flow pattern revealed by electron beam tomography (EBT), and to evaluate their usefulness in the differential diagnosis of pulmonary nodules. MATERIALS AND METHODS: A prospective perfusion study involving 28 nodules in 23 men and five women (mean age, 57 years) was performed using EBT with the multislice flow mode. There were four phases. Precontrast density (Hounsfield units, HU) in phase 0; perfusion, peak HU and time to peak in phase 1; and mean HU and percentage decrease of HU to peak HU of phase 1 in phases 2 and 3 were measured and compared according to the diagnosis. RESULTS: Malignancy was diagnased in 19 cases [primary lung cancer (n=14); metastatic nodules (n=5)], while nine nodules were benign. Perfusion was significantly higher in malignant nodules than in benign (p<0.001) and a higher mean delay 1 HU (p<0.05) and a significantly short time to peak (p<0.05) were recorded in malignant nodules. In primary lung cancer cases, perfusion was significantly high compared with benign nodules (p<0.001), and a mean delay 1 HU was observed (p<0.05). There was no significant difference in perfusion between primary lung cancer and metastasis. CONCLUSION: Perfusion and flow pattern data measured by EBT can provide the useful information for differentiation between malignant and benign pulmonary nodules.

Accuracy of Three-dimensional Coronary Arteriography by Electron-Beam Tomography

PURPOSE: To evaluate the diagnostic accuracy of non-invasive coronary angiography by electron beam tomography(EBT) for the depiction of coronary artery stenosis, as compared with conventional coronary angiography. MATERIALS AND METHODS: In 20 patients with no history of coronary artery disease, EBT (Imatron C-150) study was performed with EKG-gating. Forty images were obtained in each patient from the pulmonary trunk to the cardiac base at 80% R-R interval, and data were reconstructed into a three-dimensional coronary angiography. The interval between conventional coronary arteriograpy and EBT was less than 30 (mean, 9) days. Coronary arteries were divided into seven segments, and stenosis was defined as a narrowing of the luminal diameter of the coronary artery of more than 50 %. The results of EBT and of conventional angiography were compared for diagnostic accuracy. RESULTS: Conventional argiography revealed significant stenosis of the coronary artery in 12 of the 20 patients, while the use of three-dimensional coronary angiography by EBT revealed this in 16. The sensitivity and specificity of EBT were relatively high in the depiction of stenosis in the proximal left anterior descending (LAD), left circumflex (LCx), and right coronary artery (RCA) and middle LAD, but low sensitivity in the middle LCx and RCA. In the left main coronary artery, sensitivity was 50%. The sensitivity, specificity, accuracy, and positive and negative predictive values for the depiction of coronary artery stenosis with three-dimensional coronary arteriography by EBT were 79%, 95 %, 93 %, 71%, and 97 %, respectively. CONCLUSION: Three-dimensional coronary angiography by EBT is a non-invasive diagnostic modality for the depiction of proximal epicardial coronary artery stenosis and appears to be useful for excluding the probability of ischemic heart disease in a selected patient group.

Correlation Between Obstructive Coronary Artery Disease and Electron Beam Tomography Coronary Artery CalciumScan

PURPOSE: To determine the correlation between obstructive coronary artery disease and electron beamtomography coronary artery calcium(EBT CAC) scan and to measure the difference in calcium score according tosymptoms. MATERIALS AND METHODS: Fifty-six patients underwent EBT CAC scanning and either coronary angiography orstress thallium 201 scanning or the treadmill test. When the results were positive, coronary artery obstructivedisease(CAOD) was assumed to be present. The patients were divided into three groups : symptomatic CAOD,asymptomatic CAOD, and asymptomatic non- CAOD; those with a previous history of myocardial ischemia or who showedpositive results in any of the three tests relating to typical symptoms of angina were assigned to the symptomaticgroup. RESULTS: The number of cases assigned to group to group 1,2 and 3 was 19, 16 and 21, respectively; totalCAC scores were 571+/-751, 600+/-726 293+/-401, respectively. The difference in CAC score between asymptomatic CAODand asymptomatic non- CAOD was not statistically significant(p=0.079) but in asymptomatic CAOD, the score tendedto be higher. The CAC score was not different between symptomatic and asymptomatic CAOD(p>0.1). When the CACthreshold was 1, sensitivity was 89% and specificity was 14%;when the threshold was 200, sensitivity was 60% andspecificity was 67%. CONCLUSION: When the EBT CAC score is high, further evaluation provides early evidence ofcoronary artery obstructive disease.