Biomedical subjects

Li-ren Zhang

Publications and source records attributed to Li-ren Zhang.

5 recordsLinked to original sources

PubMed2006

[Comparison of coronary artery bypass graft imaging between 64-slice and 16-slice spiral CT].

OBJECTIVE: To compare the coronary artery bypass graft (CABG) imaging between 16-slice spiral CT and 64-slice spiral CT. METHODS: Totally 27 patients with CABG received multi-slice spiral CT imaging and the results were retrospectively analyzed. Among them, 8 patients received 16-slice spiral CT scanning, 19 patients received 64-slice spiral CT scanning. RESULTS: The evaluability rates of 64-slice spiral CT in evaluating the proximal anastomosis, bypass graft, distal anastomosis, and distal blood vessel were 100%, 100%, 90.2%, and 93.9%, respectively, while those of 16-slice spiral CT were 92.3%, 95.2%, 90.0%, and 90.0%, respectively. The patency rates of the above four aspects of 64-slice spiral CT were 66.7%, 70.0%, 71.7%, and 70.0%, respectively, while those of 16-slice spiral CT were 83.3%, 85.0%, 83.3%, and 88.9% . CONCLUSIONS: 64-slice spiral CT is superior to 16-slice spiral CT in CABG imaging. It can be used as a non-invasive tool for the post-operative follow-up of CABG.

Aged↗

PubMed2006

[Comparison of coronary angiography between 64-slice and 16-slice spiral CT].

OBJECTIVE: To compare the image quality and visibility of arteries of 64-slice spiral coronary CT angiography (CTA) with those of 16-slice spiral coronary CTA, and to evaluate the diagnostic accuracy of 64-slice spiral CT for the assessment of coronary artery stenosis. METHODS: Totally 100 patients (Group A) with suspected coronary artery diseases (CAD) were examined by 64-slice spiral CT, 48 of whom also underwent conventional coronary angiography (CAG). Another 100 patients (Group B) with suspected CAD were studied by 16-slice spiral CT. Patients with a heart rate above 70 bpm received oral beta-blockers before the scan. Data were retrospectively analyzed and reviewed by two observers. Image quality was assessed by using a 3-point grading scale from excellent (1) to non-assessable (3) and the rate of displayed coronary branches was calculated. The left main artery (LM), left anterior descending artery (LAD), circumflex artery (CX), and right coronary artery (RCA) were screened for the presence of over 50% stenosis. RESULTS: The mean heart rates of two groups showed no significant difference [(61 +/- 8) bpm vs. (61 +/- 7) bpm, P > 0.05]. The mean scan time of Group A was significantly shorter than that of Group B [(11.9 +/- 0.9) s vs. (22.2 +/- 1.1) s, P < 0.01]. In the evaluation of image quality, better results were obtained in Group A than in Group B (1.20 +/- 0.47 vs. 1.37 +/- 0. 63, P < 0.05). The visibility of proximal arteries was similar between two groups, while the visibility of some distal arteries and small branches was found higher in Group A than in Group B (LAD distal 92% vs. 48%, CX distal 98% vs. 89%, the first obtuse marginal (OMI) 93% vs. 84%, cone branch (CB) 86% vs. 71%, P < 0.05). Compared with CAG, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 64-slice spiral coronary CTA to identify over 50% stenosis were 94.9% (56/59), 93.2% (124/133), 86.2% (56/65), and 97.6% (124/127), respectively. CONCLUSIONS: With higher temporal and spatial resolution, 64-slice spiral CT provides improved image quality and visibility of small branches as compared with 16-slice spiral CT. 64-slice spiral coronary CTA allows reliable non-invasive diagnosis of obvious coronary artery stenosis.

Aged↗

PubMed2006

[Assessment of coronary stent lumen visibility and patency by 64-slice spiral CT angiography].

OBJECTIVE: To evaluate the clinical value of assessment of coronary stent patency by 64-slice spiral CT coronary angiography. METHODS: Totally 29 patients (59 stents) were investigated using a retrospective ECG-gated enhanced scan by 64-slice spiral CT at a mean interval of (28.4 +/- 21.2) months after coronary stent implantation. Axial multi-planar reconstruction (MPR) of the stents and curved-planar reconstruction (CPR) through the stents were evaluated for image quality on a 5-point scale (1 = excellent, 5 = uninterpretable) and lumen diameter. Stent lumen diameter was compared with the vessel diameter proximal of the stents to assess the in-stent lumen visibility. Conventional coronary angiography was performed in 5 patients, and 9 stents were evaluated. RESULTS: The image quality was good to excellent on average (scores: 1.94 +/- 0.84), depending on heart rate, breath movement, and stent location. Stent lumen was visible, on average a percentage off (76.1 +/- 11.1)% of the lumen diameter. All the 9 stents were correctly detected as being patent, which was confirmed by conventional coronary angiography. CONCLUSION: 64-slice spiral CT is a useful tool to assess the coronary stent patency.

Adult↗

PubMed2006

[Assessment of global left ventricular function with multi-slice spiral computed tomography].

OBJECTIVE: To investigate the value of multi-slice spiral computed tomography (MSCT) in the determination of global left ventricular function. METHODS: Twenty-nine patients with confirmed or suspected coronary heart diseases were imaged with a contrast-enhanced retrospective electrocardiogram (ECG) -gated technique on a 64-slice spiral CT scanner. The data sets were reconstructed at both end-diastolic and end-systolic phases in order to measure left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular stroke volume (LVSV), and left ventricular ejection fraction (LVEF). The results were compared with corresponding values obtained from conventional left ventriculography (LVG). RESULTS: LVEDV, LVESV, LVSV, and LVEF obtained with 64-slice spiral CT were significantly correlated with the LVG data (r = 0. 887-0.956, P < 0.001). According to the Bland-Altman approach, the mean differences for LVEDV, LVESV, LVSV, and LVEF were -2.3 ml, 4.1 ml, -6.4 ml, and - 3.5%, respectively. The limits of agreement for LVEDV, LVESV, LVSV, and LVEF were -27.2-22.4 ml, -10.2-18.4 ml, -26.4-13.6 ml, and -9.8%-3.0%, respectively. CONCLUSION: MSCT has clinically acceptable agreement with LVG for the quantification of global left ventricular function.

Adult↗

PubMed2003

[Coronary angiography with sixteen-slice spiral CT: an initial study].

OBJECTIVE: To evaluate the scanning technique and primary clinical value of sixteen-slice spiral CT coronary angiography. METHODS: Plain and enhanced sixteen-slice spiral CT imaging was performed in 69 patients, including 64 cases of suspected coronary heart disease and 5 cases of coronary stent. Calcium scoring with plain scan images and MPR, MIP and VRT reconstruction with enhanced scan images were made in all cases, among which 10 underwent conventional coronary angiography. The demonstration and stenosis of coronary arteries were evaluated. The factors influencing the image quality were analyzed. Additional MPR and MIP reconstruction of slices perpendicular to the stent and virtual endoscopy of stent were made in 7 stents of the 5 cases of coronary stent. The patency of the stents was evaluated. RESULTS: A four-step scanning procedure was devised. Coronary calcium score could be got by plain scanning with sixteen-slice spiral CT angiography. All of the primary, most of the secondary and tertiary, and part of the fourth level branches of coronary artery could be shown isotropically with MPR, MIP and VRT reconstruction images of enhanced scanning. MPR and MIP were better than VRT in demonstrating small branches. Evaluated by VRT image, the image quality of 79.7% of the patients were first class, 10.1% second class, and 10.1% third class. The image quality was correlated to the contrast concentration in the root of aorta, heart rate, existence or absence of arrythmia, and the patient's breath-holding ability. Stenosis of coronary arteries was evaluated by sixteen-slice spiral CT imaging in 10 cases, with a result comparable to that by conventional coronary angiography. The stents were well shown, six stents being evaluated as patent, while one not. CONCLUSION: Sixteen-slice spiral CT coronary angiography is a noninvasive, simple and good method. Coronary calcium score and coronary artery stenosis can be evaluated with one study. The patency of stents can also be evaluated.

Adult↗