Combined CT angiography and SPECT myocardial perfusion imaging for the detection of functionally relevant coronary stenoses.

The present study aimed to discuss and evaluate the diagnostic performances and incremental clinical values of combined computed tomography coronary angiography (CTCA) and single photon myocardial perfusion imaging (MPI) for the detection of functionally relevant coronary stenoses (FRCS). In total, 54 patients underwent CTCA, MPI and coronary angiography (CAG) within 30 days. The diagnostic performances of CTCA and combined CTCA plus MPI for the detection of significant coronary stenoses (≥50%) were calculated on the patient­ or vessel­based levels and included the indices of sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) and accuracy (AC). On the patient­based level, the SP, PPV, NPV and AC of CTCA alone or combined with MPI in the detection of FRCS were 90.9 and 90.9, 71.9 and 96.9, 69.0 and 95.2, 92.0 and 93.9 and 79.6 and 94.4%, respectively. On the vessel­based level, the SN, SP, PPV, NPV and AC of CTCA alone or combined with MPI in the detection of FRCS were 90.3 and 90.3, 87.6 and 98.9, 54.9 and 93.3, 98.2 and 98.4 and 88.0 and 97.7%, respectively. The PPV, SP and AC of combined CTCA and MPI in the detection of FRCS were significantly improved compared with CTCA alone (all values, P<0.05). The diagnostic performance of combined CTCA and MPI in the detection of FRCS not only retains a high SN and NPV, but also markedly improves SP, PPV and AC, which should play an incremental and significant role in the decision­making process for the revascularization therapy of coronary artery disease (CAD).

Comparative Analysis between SPECT Myocardial Perfusion Imaging and CT Coronary Angiography for Diagnosis of Coronary Artery Disease.

The study aims to discuss the relationship and difference between myocardial perfusion imaging (MPI) using SPECT and CT coronary angiography (CTCA) for diagnosis of coronary artery disease (CAD). Five hundred and four cases undergoing MPI and CTCA were comparatively analyzed, including fifty six patients undergoing invasive coronary angiography in the same period. Among patients with negative MPI results, negative or positive CTCA occupied 84.7% or 15.3%, respectively. Among patients with positive MPI, positive or negative CTCA occupied 67.2% or 32.8%, respectively. Among patients with negative CTCA, negative or positive MPI occupied 94.4% or 5.6%, respectively. Among patients with positive CTCA, positive or negative MPI occupied 40.2% or 59.8%, respectively. Negative predictive value was relatively higher than the positive predictive value for positive CTCA eliminating or predicting abnormal haemodynamics. And there was no significant difference for sensitivity, specificity, and accuracy of MPI or CTCA in diagnosing CAD. Both MPI and CTCA have good diagnostic performance for CAD. They provide different and complementary information for diagnosis and evaluation of CAD, namely, detection of ischemia versus detection of atherosclerosis, which are quite different but have a definite internal link for each other.

[Coronary artery lumen diameter and bifurcation angle derived from CT coronary angiographic image in healthy people].

OBJECTIVE: To observe the coronary vessel lumen diameter and bifurcation angle in subjects with normal CT coronary angiography (CTCA) imaging. METHODS: 64-row CT coronary angiography imaging from 526 adult people with excellent image quality and normal vascular image were analyzed in this study. The lumen diameter from the origin to distal with 2 mm lumen of left main coronary artery (LM), anterior descending branch (LAD), left circumflex branch (LCX) and right coronary artery (RCA) was measured at 1 cm interval in CPR image. The vascular tapered ratio was calculated. The bifurcation angle in the diagonal branch, obtuse marginal branch, posterior descending branch, acute marginal branch as well as the origin diameter was also measured in VR image. RESULTS: The LAD average length was 13 cm and lumen diameter was 3.92 mm at origin and 2.10 mm at distal. The average decremented ratio of LAD was 7.7% (male 7.0%, female 8.4%). The maximal decremented ratio 8.0% - 10.0% occurred at 3 - 5 cm apart from the origin of LAD. The LCX average length was 13 cm and lumen diameter was 3.57 mm at origin and 2.10 mm at distal. The average decremented ratio of LCX was 9.7% (male 9.6%, female 9.7%). Lumen decremented ratio was less than 3.0% between origin and proximal 3 cm and 8.3% - 10.7% in the rest portion of the LCX. The RCA average length was 18 cm and lumen diameter was 3.97 mm at origin and 2.15 mm at distal. The average decremented ratio of RCA was 5.1% (male 4.9%, female 5.3%). The decremented ratio of RCR was less than 4.0% between origin and proximal 10 cm and 6.1% - 15.2% in the rest portion. The bifurcation angle was 50, 55, 66 and 76 degree for LAD with diagonal branch, LCX with obtuse marginal branch, RCA with posterior descending branch and RCA with obtuse marginal branch respectively. CONCLUSION: Coronary artery length, lumen diameter and decremented ratio as well as bifurcation angel could be identified in 64 row CTCA image in vivo. This information could help us to understand the in vivo coronary artery anatomy.

[Evaluation of cardiac structure and function by cardiac magnetic resonance imaging in healthy volunteers].

OBJECTIVE: To evaluate the role of cardiac magnetic resonance (CMR) sequence in assessing the cardiac structure and function. METHODS: A total of 36 healthy volunteers were examined with fast imaging employing steady-state acquisition cine MR sequence. All the MR images were processed on Report Card software to test the cardiac dimensions and function. The relationships between the CMR results and the ultrasonic cardiography (UCG) results were analyzed. RESULTS: CMR analysis showed that interventricular septum thickness, left ventricle posterior wall thickness, end diastolic dimension of left ventricle, and end systolic dimension of left ventricle were (9.2 +/- 2.1), (8.0 +/- 2.1), (48.6 +/- 5.5), and (30.3 +/- 5.3) mm, respectively. Major dimension of right ventricle, minor dimension of right ventricle, index of major, dimension of right ventricle and index of minor dimension of right ventricle were (69.2 +/- 9.7), (30.6 +/- 6.6) mm, and (39.4 +/- 5.5), (18.1 +/- 3.4) min/m2, respectively. The left ventricle indicators above measured by CMR correlated with those by UCG (r = 0.843, 0.784, 0.686, 0.730, all P < 0.01). CMR analysis showed that left ventricular end diastolic volume, right ventricular end diastolic volume, left ventricular end systolic volume, and right ventricular end systolic volume were (93.6 +/- 17.2), (108.6 +/- 28.2), (39.5 +/- 13.0), and (45.6 +/- 15.1) ml, respectively. The left ventricular ejection fraction and right ventricular ejection fraction were (58.5 +/- 8.19)% and (58.2 +/- 7.4)% , respectively. Left ventricular ejection fraction measured by CMR was correlated with that (64.1 +/- 6.8)% by UCG (r = 0.75, P < 0.01). CONCLUSIONS: CMR sequence with standard location is well applicable for accurate measurement of left and right ventricle dimensions and function, especially for right ventricle. CMR can be used to diagnose the heart disease and monitor the efficacy.

[Assessment of global left ventricular function by 64-slice spiral CT in patients with old myocardial infarction].

OBJECTIVE: To investigate the clinical value of 64-slice spiral CT (64SCT) in assessing global left ventricular function in patients with old myocardial infarction (OMI), with magnetic resonance imaging (MRI) as the reference standard. METHODS: A total of 28 patients (23 men and 5 women) with OMI underwent contrast-enhanced 64SCT with retrospective electrocardiographic-gating, MRI, and transthoracic echocardiography (Echo). The data sets of 64SCT and MRI were reconstructed at both end-diastole and end-systole to measure left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejective fraction (EF), and myocardial mass at end-diastole (MM). The data acquired with 64SCT and Echo were compared with the results obtained on MRI as the standard of reference respectively. RESULTS: The parameters of global left ventricular function obtained with 64SCT were significantly correlated with the MRI data (r = 0.788-0.976, P < 0.001). EDV, ESV, SV, EF, and MM were slightly overestimated by 64SCT compared with MRI; however, there was no significant difference among the measurements. 64SCT was in good agreement with MRI. For the EDV, ESV, SV, and EF, the limits of agreement with Echo were significantly larger than with 64SCT compared with MRI (P < 0.05). The sensitivity, specificity, and accuracy of 64SCT to identify EF value less than 50% were 84.6%, 100% and 92.9%, respectively, whereas those of Echo were 61.5%, 66.7% and 64.3%, respectively. The accuracy of 64SCT was significantly higher than that of Echo (P < 0.01). There was a significantly larger overestimation of EDV, ESV, and SV with Echo than with 64SCT compared with MRI (P < 0.05), whereas EF was not significantly different. CONCLUSIONS: A strong correlation between 64SCT and MRI is found for all parameters. 64SCT agrees well with MRI, and allows more reliable and accurate evaluation of global left ventricular function in patients with OMI than Echo compared with MRI.

[An experimental study on percutaneous autologous bone marrow mesenchymal stem cell grafting for bone defect].

OBJECTIVES: To investigate in vive osteogenic potential in size-critical bone defect after percutaneous autologous grafting of culture-expanded rabbit autologous BMSCs, osteo-induced BMSCs and combination of both. METHODS: BMSCs were cultured and then induced with osteogenic supplement (OS) medium. BMSCs with and without OS induction were collected and percutaneously autologously injected respectively into the 15 mm bone defect of 20 experimental rabbit model. The grafts were BMSCs, osteo-induced BMSCs, BMSCs and osteo-induced BMSCs, BMP combined with fibrin sealant, and 0.9% NaCl solution. Osteogenesis at the defect areas were observed by regular radiography, histology and biomechanics. RESULTS: The group transplanted with BMSCs + osteo-induced BMSCs achieved complete bone healing with medullary cavity united, which showed the largest quantity of new bone measured by X-ray analysis, and also their maximal load were better than those in other groups. CONCLUSION: The bone-forming ability of rabbit osteo-induced BMSCs combined with BMSCs in bone defect is superior to those of BMSCs and osteo-induced BMSCs.

Coronary angiography with dual source computed tomography: initial experience.

OBJECTIVE: To explore the scan technique and image quality of coronary angiography with dual source computed tomography (CT) without oral metoprolol preparation. METHODS: Plain and enhanced dual source CT coronary angiography without oral metoprolol preparation was prospectively performed in 600 patients. Calcium scoring with plain scan images as well as multi-planar reconstruction (MPR), maximum intensity projection (MIP), and volume rendering technique (VRT) reconstruction with enhanced scan images were performed in all cases. The scan technique and post-reconstruction experience was summarized. The image quality was classified as 1 to 4 points, and coronary segments classified according to the American Heart Association standards were evaluated. RESULTS: The average calcium score of the 600 cases was 213.6 +/- 298.7 (0-3,216.5). The average heart rate of the enhanced scan was 82.1 +/- 16.2 (47-139) bpm. The post-reconstruction methods with which coronary segments could be shown as best as possible consisted of single phase reconstruction method, two or more phases supplemented method, and electrocardiogram editing method. Altogether 8,457 coronary segments were evaluated, among which 97.2% were evaluated as point 1, 1.7% point 2, 0.5% point 3, and 0.6% point 4. The coronary segments in 261 cases were completely normal, while 360 segments were diagnosed with < 50% stenosis and 625 segments with > or = 50% stenosis. CONCLUSIONS: Excellent coronary artery image can be obtained with dual source CT in patients with any heart rate without oral metoprolol preparation. Heart rate is not a major source of the artifact, coronary segments can be well shown with single or multiple-phase reconstruction method.

[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.

[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.

[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.

[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.

Retrospective analysis of magnetic resonance myocardial delayed enhancement.

OBJECTIVE: To explore the imaging and related clinical characteristics of magnetic resonance (MR) delayed enhancement in patients with ischemic or nonischemic heart disease. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Non-invasive imaging of coronary artery with 16-slice spiral computed tomography.

OBJECTIVE: To evaluate the value of 16-slice spiral CT in the demonstration of coronary artery and in the diagnose of coronary artery stenosis. METHODS: Plain and enhanced CT scans were performed with a 16-slice CT scanner (Sensation 16, Siemens, Germany) in 230 patients with suspected coronary heart disease (CHD). Parameters of the plain scan were: 120 kV, 133 mA, slice collimation 16 mm x 1.5 mm, rotation time 0.42 seconds, increment 1.5 mm, and slice width 3 mm. Parameters of the enhanced scan were: 120 kV, 500 mA, slice collimation 16 mm x 0.75 mm, rotation time 0.42 seconds, increment 0.5 mm, and slice width 1 mm. Enhanced CT scan was performed with a rapid intravenous injection of 100 mL iothalamate meglumine (Ultravist) (370 mgI/mL) or Omnipaque (350 mgI/mL) and 30 mL 0.9% NaCl chaser bolus at a flow rate of 3.5 mL/s. Calcium scoring with plain scan images and two and three dimensional reconstruction with enhanced scan images were made in all cases, among which 30 cases underwent conventional coronary angiography. Demonstration of coronary arteries and their stenosis were evaluated and the factors that might influence the image quality were analyzed. RESULTS: Coronary calcium scores were calculated and coronary artery was demonstrated in our study. In the evaluation of image quality with volume rendering technique (VRT) images, 78.3% of the images were of the first class, 12.2% the second class, and 9.6% the third class. Multi-planar reconstruction (MPR) and maximal intensity projection (MIP) were better than VRT in the demonstration of small branches. The image quality was related to the heart rate, with or without arrhythmia, and breath-hold ability of patients. Comparative study of the stenosis of coronary arteries in 30 cases showed that the sensitivity and specificity of 16-slice coronary CT angiography (CTA) to diagnose significant stenosis were 95.8% and 94.8% respectively. CONCLUSION: As a non-invasive and quick method, 16-slice coronary CTA is sensitive and specific to diagnose the stenosis of coronary arteries and can be used as a screening method in the diagnosis of CHD.

[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.