Comparison of ^(99m)Tc-methoxyisobutylisonitrile myocardial single-photon emission computed tomography and electron beam computed tomography for detecting coronary artery disease in patients with no myocardial infarction

Background Previous studies have compared single-photon emission computed tomography (SPECT) and electron beam computed tomography (EBCT) in detection of coronary artery disease (CAD) in patients with myocardial infarction (MI) The purpose of this study was to compare SPECT with EBCT in detection of CAD in patients with no MI Methods One hundred and forty-seven patients with suspected CAD underwent stress-rest 99m Tc-methoxyisobutylisonitrile ( 99m Tc-MIBI) myocardial SPECT, cardiac EBCT and coronary angiography (CAG) within one month Of them, 73 patients (aged 52 6±10 6 years old) with no history of MI were included in this study Coronary artery calcium (CAC) was defined as a CT value ≥130 HU within the boundary of coronary artery on EBCT Results There were 35 and 38 patients with or without CAD according to CAG Ninety-six percent of the patients with abnormal SPECT and CAC had a coronary arteries stenosis ≥50%, and 90 9% patients with normal SPECT and EBCT showed no CAD The sensitivity of SPECT and EBCT in detection of CAD was comparable, and the specificity of SPECT (92 1%) was significantly higher than that of EBCT (55 3%) ( P <0 005) For the detection of individual coronary artery stenosis, both sensitivity and specificity of SPECT (75 0% and 93 7%) were significantly higher than those of EBCT (53 3% and 76 7%) ( P <0 025 and P <0 005, respectively) In patients without chest pain, the sensitivity and specificity of SPECT (76 9% and 91 4%) were significantly higher than those of EBCT (23 1% and 69 0%) in detection of a coronary artery stenosis of ≥50% ( P <0 01 and P <0 005, respectively) However, in patients with chest pain, both sensitivity and specificity of SPECT were comparable to those of EBCT In patients ≤45 years old, the sensitivity of SPECT (77 8%) was significantly higher than that of EBCT (27 8%) in assessing a coronary artery stenosis of ≥50% ( P <0 005), and the specificity of SPECT was comparable to that of EBCT In patients >45 years old, the specificity of SPECT (94 3%) was significantly higher than that of EBCT (70 5%) ( P <0 005), and the sensitivity of SPECT was comparable to that of EBCT Conclusion 99m Tc-MIBI myocardial perfusion SPECT has higher accuracy than that of EBCT in detection of CAD in patients without MI

Threedimensional electron beam CT angiography in the diagnosis of intracranial aneurysms

Objective To assess the accuracy of three dimensional electron beam CT angiography (3D EBCTA) in the detection of intracranial aneurysms Methods 31 patients with suspected cerebral aneurysms (including 3 post operative patients) were examined by 3D EBCTA Those receiving angiography or surgery acted as controls Maximum intensity projection (MIP) and shaded surface display (SSD) reconstruction ways were selected Results 24 aneurysms were found in 23 patients Of the 31 patients, false positive was noted in 1 patient,and false negative in 2 on 3D EBCTA The sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 92 0%, 88 9%, 91 2%, 95 8% and 80 0% respectively Conclusion 3D EBCTA is an noninvasive, rapid, valuable method in diagnosis and screening of patients with suspected aneurysms The reconstruction modes such as MIP and SSD should be used together to optimise the visualization