Coronary computed tomographic angiography using low-dose prospectively electrocardiographic triggered high-pitch spiral acquisition by dual-source computed tomography: image quality and radiation dose / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate image quality (IQ) and radiation exposure of coronary computed tomographic angiography (CTA) with prospectively electrocardiographic (ECG) triggered high-pitch spiral acquisition using dual source CT.</p><p><b>METHODS</b>Totally 75 consecutive patients with a stable heart rate (HR) ≤65 bpm underwent coronary CTA. patients were divided into two groups according to their HR (group A HR≤60 bpm, group B HR >60 bpm to≤65 bpm) . A dual-source CT scanner was used (0.6mm collimation, 0.28s rotation time, 80~100 kV, 370 mAs/rot) . Data acquisition was prospectively ECG-triggered at 60% of the R-R interval with a pitch of 3.4. Images were reconstructed with 75ms temporal resolution, 0.75mm slice thickness and 0.5mm increment. IQ was evaluated using a four-point scale (1=excellent, 4=unevaluable) .</p><p><b>RESULTS</b>The mean HR and scan time of all patients was (57.2 ± 4.8) bpm and (0.42 ± 0.02) s. Of 1103 coronary artery segments, 934 (84.7%) had an IQ score of 1, 135 (12.2%) score of 2, 18 (1.6%) score of 3,and 16 (1.5%) were rated as unevaluable. There was no significant difference between the two groups in IQ [mean score (1.19 ± 0.52 vs. 1.22 ± 0.55;Z=-1.107,P=0.268) . The rate of evaluable segments showed no significant difference between the two groups (98.5% vs. 98.6%;X2=0.000,P=1.000) . Mean dose-length product of all patients was (67.2 ± 30.4) mGy × cm, mean effective dose was (0.94 ± 0.43) mSv.</p><p><b>CONCLUSION</b>In patients with a stable HR of 65 bpm or less, prospectively ECG-triggered high-pitch spiral CT acquisition provides high IQ at low radiation dose.</p>

Computed tomographic angiography for evaluation of the relationship between coronary artery stenosis and head and neck artery stenosis / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the relationship between coronary artery stenosis and internal carotid artery, vertebral and basilar artery stenosis using computed tomographic angiography.</p><p><b>METHODS</b>The imaging and clinical data of 84 patients who underwent coronary, head and cervical computed tomographic angiography in our hospital between September 2008 and June 2010 were retrospectively analyzed. Segment stenosis scoring was performed to quantify the degree of stenosis of coronary arteries. The relationship between the segment stenosis scoring and the degree of stenosis for internal carotid artery, vertebral and basilar artery was analyzed.</p><p><b>RESULT</b>The coronary segment stenosis scores were significantly correlated with the degree of stenosis for internal carotid artery, vertebral and basilar artery (r=0.450 and 0.475,P<0.05) .</p><p><b>CONCLUSION</b>The degree of the stenosis of coronary artery is associated with the stenosis of internal carotid artery, vertebral and basilar artery, which can be confirmed by computed tomographic angiography."</p>

Dual-source computed tomographic angiography using triple-rule-out protocols in combination with abdominal computed tomographic angiography for evaluation of aortic dissection / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the clinical value of "triple-rule-out" protocols using dual-source computed tomography for aortic dissection (AD) assessment.</p><p><b>METHODS</b>Totally 25 patients suspecting of suffering from AD were examined on a dual-source computed tomography scanner. Two-dimensional and three-dimensional reconstruction was performed in all patients by means of multiplanar reconstruction, curved planar reformation, maximum intensity projection, and volume rendering. All images were read by two experienced radiologists in consensus. All patients were divided into AD group (n=12) and NO AD group (n=13) , The average Hounsfield unit values of true and false lumen were compared between superior of the aortic around the first endoleak and inferior of the aortic around renal artery.</p><p><b>RESULTS</b>In AD group, there were 6 patients with DeBakey type 1, 2 patients with DeBakey type 2, and 4 patients with DeBakey type 3. The image quality was rated on a 3-point scale as excellent in 10 patients (83.3%) and good in 2 patients (16.7%) . All cases was fully evaluable in NO AD group. The average Hounsfield unit values of true lumen between superior of the aortic around the first endoleak and inferior of the aortic around renal artery showed no significant difference between AD and NO AD group.</p><p><b>CONCLUSION</b>Dual-source computed tomography offers a non-invasive, accurate, and rapid way to evaluate AD.</p>

Retrospective analysis of magnetic resonance myocardial delayed enhancement / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To explore the imaging and related clinical characteristics of magnetic resonance (MR) delayed enhancement in patients with ischemic or nonischemic heart disease.</p><p><b>METHODS</b>Thirty-two cases who underwent MR myocardial cine and delayed enhancement imaging from January 2004 to October 2006 were retrospectively analyzed. The cine sequence imaging included the four-chamber view and the left ventricular short axis view. The delayed enhancement imaging was taken 10 minutes after the infusion of gadolinium from the antecubital vein with a segmented inversion-recovery-prepared T1-weighted fast gradient echo sequence. Patients underwent coronary computed tomography angiography (CTA) two weeks before or after the MR imaging examination. Combined with clinical history, the clinical and MR imaging characteristics of the patients who had delayed enhancement were analyzed.</p><p><b>RESULTS</b>MR delayed enhancement could be found in 16 cases. Among them, 12 cases had ischemic heart disease. Their coronary CTA showed one to three vessel diseases. The delayed enhancement was transmural or subendocardium, and the area of delayed enhancement corresponded well with one or more coronary arteries which had severe stenosis or occlusion. Four cases had nonischemic heart diseases. One case was dilated cardiomyopathy, with diffuse small midwall spots in delayed enhancemen and only 30% stenosis of the anterior descending coronary artery in coronary CTA. One case was hypertrophic cardiomyopathy, with delayed enhancement of strip- and patch-shaped at midwall of the hypertrophic myocardium. One case was restrictive cardiomyopathy, and the delayed enhancement was located in the area of subendocardium of both the right and left ventricles. Coronary CTA of these two cases were normal. The other case was a mass of the lateral wall of the left ventricle, and the delayed enhancement with a clumpy shape was located in the lateral wall of the left ventricle.</p><p><b>CONCLUSIONS</b>MR myocardial delayed enhancement is not a specific sign of myocardial infarction of ischemic heart disease. Nonischemic heart diseases including all kinds of primary cardiomyopathy and some other diseases affecting myocardium can also cause delayed enhancement, but their characteristics are different. The differentiation of the etiology of the nonischemic heart disease with delayed enhancement relies upon the intimate connection with clinical history and the cine sequence MR images.</p>