CTCA联合CT首过心肌灌注成像检查在无症状性心肌缺血诊断中的应用效果

目的分析CT冠状动脉(CTCA)联合CT首过心肌灌注成像(CT first－pass MPI)检查在无症状性心肌缺血(SMI)诊断中的应用价值。 方法选取2016年4月至2017年12月胶州市人民医院收治的79例疑似SMI患者,均行核素心肌灌注成像(MPI)、CTCA检查、CT first－pass MPI检查,以MPI检查结果为准,统计CTCA检查、CT first－pass MPI检查、联合检查确诊SMI情况及诊断灵敏度、准确度、特异度。 结果79例SMI患者中：MPI检出48例SMI,31例无心肌缺血;CTCA检出50例SMI,29例无心肌缺血;CT first－pass MPI检出53例SMI,26例无心肌缺血;联合检查检出54例SMI,25例无心肌缺血;CTCA检查、CT first－pass MPI检查、联合检查灵敏度、准确度比较差异显著(P<0.05);联合检查灵敏度95.83%、准确度87.34%高于CTCA检查72.92%、64.56%(P<0.05)。 结论CTCA与CT first－pass MPI联合应用诊断SMI,不仅可了解冠脉狭窄程度与位置,亦可观察心肌血流灌注情况,诊断价值较高。     

老年冠心病患者无症状心肌缺血的临床研究

目的 :探讨老年冠心病患者无症状性心肌缺血 （SMI）的临床特点和发生规律。方法 :对 2 5 6例老年冠心病患者行 2 4 h动态心电图检测 ,检出心肌缺血 16 7例 ,按临床情况分为 3组 : 组 :单纯 SMI; 组 :有心绞痛史的患者 ; 组 :心肌梗死后患者。结果 :SMI的发生明显高于有症状性心肌缺血 ,占 84 .3% ,发作时间主要是白天 ,以上午 6～ 12点发作最频 ,0～ 6点最少。 , , 组的心肌缺血程度 （SMI发作次数 ,缺血持续时间 ,ST段压低幅度 ）及室性心律失常发生率依次增加 ,而 SDNN和 HRVI依次递减。结果表明 ,心肌缺血程度与室早发生率呈正相关 ,与SDNN,r MSSD,PMN50 及 HRVI呈负相关。结论 :SMI是老年冠心病最常见的表现形式 ,应引起足够重视。冠心病患者心脏自主神经受损程度随着心肌缺血程度而加重     

Radiation dose difference between state of the art myocardial perfusion scintigraphy and computed tomography coronary angiography in patients undergoing evaluation for suspected coronary artery disease

Minimisation of radiation exposure with cardiac imaging reduces the potential of secondary side effects. Radiation exposure from myocardial perfusion scintigraphy and computed tomography coronary angiography (CTCA) was compared. Overall doses were low with both modalities. Doses were lower in the CTCA group, but by only a small difference of 1.1 mSv. Radiation exposure should not be the primary consideration when choosing between these two modalities.     

Assessment of myocardial perfusion for detection of coronary artery stenoses by steady-state, free-precession magnetic resonance first-pass imaging

Objective

To evaluate the diagnostic impact of magnetic resonance imaging (MRI) first‐pass perfusion using steady‐state, free‐precession (SSFP) sequences with parallel imaging (SENSE) for detection of coronary stenoses.

Design

Prospective observational study.

Setting

University hospital, cardiac MRI and catheterisation laboratories.

Patients and methods

228 patients were examined with coronary angiography and MRI (1.5 T Intera CV). A three‐slice, short‐axis SSFP perfusion scan with a saturation prepulse was performed during infusion of adenosine and at rest followed by myocardial scar (late enhancement) imaging. Gadolinium‐DTPA was given at 0.1 mmol/kg body weight. Perfusion images were visually assessed. Analysis for myocardial hypoperfusion was done according to patient group and according to vessel.

Results

Sensitivity, specificity and accuracy of MRI first‐pass perfusion for detection of a coronary artery stenosis (>50% luminal narrowing) in the total patient group were 93.0%, 85.7%, 91.2% and for a significant lesion (>70% luminal narrowing) 96.1%, 72.0%, 88.2%, respectively. Based on 536 coronary artery territories without myocardial scar, the sensitivity of MRI perfusion analysis for detection of a significant lesion was for the left anterior descending artery 91.4%, for the circumflex artery 81.6% and for the right coronary artery 65.1% (p<0.001).

Conclusions

MRI first‐pass perfusion analysis using an SSFP sequence with three myocardial slices was a highly accurate diagnostic method for detection of coronary artery stenoses. This MRI technique can be included in daily practice and has the potential to guide the indication for invasive coronary angiography.     

The association of coronary non-calcified plaque loading based on coronary computed tomography angiogram and adverse cardiovascular events in patients with unstable coronary heart disease-a retrospective cohort study

BackgroundCoronary computed tomography angiogram (CCTA) has the characteristics of non-invasive, high resolution, and can accurately determine the characteristics of tubular wall plaques. The non-calcified plaque loading of the coronary arteries is unstable and prone to shedding, leading to adverse cardiovascular events. However, few studies focused on the predictive value of non-calcified plaque loading for adverse cardiovascular events in patients with unstable coronary heart disease (CHD). The present study was conducted to investigate the association of coronary non-calcified plaque loading based on CCTA and adverse cardiovascular events in patients with unstable CHD.MethodsA total of 206 patients with unstable CHD were collected and followed up for 1 year. The patients were divided into an observation group (n=56) and a control group (n=150) according to whether adverse cardiovascular events occurred or not. We analyzed the predictive value of coronary artery non-calcified plaque loading for adverse cardiovascular events in unstable CHD using receiver operating characteristic and multivariate logistics regression analysis.ResultsCompared with the control group, the non-calcified plaque volume in the observation group was increased (160.10±44.02 vs. 128.06±42.22 mm³, P=0.000); non-calcified plaque loading increased (26.93%±7.98% vs. 21.46%±7.62%, P=0.000); carotid intima-media thickness increased (1.49±0.17 vs. 1.40%±0.18 mm, P=0.001); and left ventricular ejection fraction (LVEF) was significantly reduced (53.28%±7.39% vs. 58.02%±7.91%, P=0.000). Non-calcified plaque volume and non-calcified plaque loading have certain diagnostic value for recurrence of adverse cardiovascular events within 1 year (P<0.05). A non-calcified plaque volume >145.58 mm³ is a risk factor for recurrence of adverse cardiovascular events (P<0.05).ConclusionsIncreased non-calcified plaque volume in patients with unstable CHD is associated with the development of adverse cardiovascular events in patients with unstable CHD.     

Correlation between myocardial enzyme serum levels and markers of inflammation with severity of coronary artery disease and Gensini score: A hospital-based,prospective study in Greek patients

Background

Our objective was to associate serum levels of myocardial enzymes and inflammatory biomarkers with severity of coronary artery disease (CAD).

Patients and methods

123 patients participated in our study, including 65 cases of acute myocardial infarction (MI), 27 cases of newly diagnosed CAD – without MI – and 31 controls. In all subjects, myocardial serum enzyme levels (creatine phosphokinase, aspartate aminotransferase, lactate dehydrogenase) and inflammatory indices (C-reactive protein, fibrinogen, white blood cells, and erythrocyte sedimentation rate) were measured. Patients were all submitted to coronary angiography and CAD severity was evaluated by Gensini score.

Results

Significant differences concerning enzyme serum levels and inflammatory indices were found to exist between the three study groups, being highest among patients with acute MI (p < 0.001). A significant association was demonstrated between Gensini score and serum enzyme levels as well as inflammatory biomarkers.

Conclusions

Our findings suggest that serum levels of myocardial enzymes and inflammatory indices correlate with CAD severity in Greek patients.     

Feasibility and accuracy of coronary imaging in elderly patients using the 64-row multi-detector computed tomography: a correlation study with conventional coronary angiography

Background Elderly patients generally have higher occurrence of coronary calcification, increased heart rate and difficulty with prolonged breath-holding. The aim of our study was to investigate the feasibility and accuracy of using 64-row multi-detector computed tomography (MDCT) in the assessment of coronary artery stenoses in elderly patients. Methods One hundred and fifty two patients with suspected or known coronary artery disease were divided into 4 groups according to their age (Group A: 40-49 years, n=34; Group B: 50-59 years, n=57; Group C: 60-69 years, n=48; Group D: 70 years and above; n=13). Coronary CT angiography (CTA) using a 64-row MDCT was performed and the findings were compared with that of conventional coronary angiography (CCA). Using axial images, multi-planar reconstructions (MPR) and maximum intensity projections (MIP), coronary segments of lumen diameter = 1.5mm were analyzed for the presence of significant stenosis (= 50% ). Results Percentages of poor image quality from coronary CTA preventing reliable correlations with CCA were 21%, 14%, 19% and 62% in Groups A to D respectively. Patients in Group D had significantly higher calcium scores compared with the other groups (P<0.001). In patients where CTA images were of acceptable quality, percentages of accurate correlations with CCA were 89.8%, 93.4%, 86.6% and 78.0% for Groups A to D respectively. There were no significant difference in serum creatinine, heart rate and contrast volume between the 4 groups. Conclusions The 64-row MDCT coronary angiography was less accurate and feasible for patients aged 70 years or above due to heavy coronary calcification and inability to perform a satisfactory breath-hold. However, a high diagnostic accuracy with the MDCT is possible in patients aged less than 70 years.(J Geriatric Cardiol 2006;3(1):9-14)     

4种无创性检查及其组合对冠心病诊断的辅助作用研究

目的评价几种无创性检查联合临床危险因素对冠心病诊断的辅助价值。方法选择2001年1月至2007年3月在全国20家三级甲等医院心内科住院疑诊冠心病并初次行诊断性冠状动脉造影(CAG)的患者。纳入常见的临床危险因素后,评价4种无创性检查(包括动态心电图、负荷心电图、负荷核素心肌显像、冠脉CT)及其组合对冠心病诊断的敏感度、特异度。结果无创性检查组合在冠心病诊断中的敏感度为56.02%～87.43%,特异度为36.13%～89.66%,阳性预测值为58.83%～97.73%,阴性预测值为30.21%～73.36%。将危险因素纳入后共同参与判别,未提高判别能力。结论无创性检查组合可作为诊断冠心病的重要方法,动态心电图和冠脉CT组合可作为各级别医院冠心病筛查的基本及重要手段,临床危险因素未增加冠心病诊断的判别能力。     

Echocardiography with tissue harmonic imaging in the detection of st segment elevation myocardial infarction: comparison with coronary angiography

BACKGROUND: Tissue harmonic imaging (THI) has been used to improve endocardial border definition and cardiac structure visualization in patients with poor quality echocardiograms. However, little is known about the usefulness of THI in the detection of acute myocardial infarction. METHODS: Ninety-eight patients with a first ST segment elevation myocardial infarction were investigated using THI and coronary angiography. RESULTS: Using THI, adequate quality echocardiograms were obtained in 95.9% of the patients. THI detected myocardial infarction in 92.9% of the patients. The sites of myocardial infarction estimated by THI and echocardiogram were nearly consistent. The sites of myocardial infarction estimated by THI were in accordance with the territories subtended by the infarct-related artery in coronary angiography (accuracy 88.8%), among which the highest accuracy (96.8%) concerning infarcts caused by left anterior descending branch disease. Infarcts involving inferior, posterior wall, or right ventricle were commonly complicated with myocardial infarction of other location, and were more likely to be missed. CONCLUSIONS: Echocardiography with THI is a sensitive technique for detecting ST segment elevation myocardial infarction. More attention should be paid to the observation of inferior, posterior wall, or right ventricle to avoid missing the detection of myocardial infarction involving these sites.     

99mTc-MIBI SPECT负荷心肌灌注显像对怀疑心肌缺血糖尿病患者的预后价值

目的评价~(99m)锝-甲氧基异丁基异腈(~(99m)Tc-MIBI)SPECT负荷心肌灌注显像(MPI)对怀疑心肌缺血的糖尿病患者主要不良心血管事件(MACEs)是否具有预测作用。方法回顾性分析2013年6月至2016年3月首都医科大学附属北京友谊医院因怀疑心肌缺血而行~(99m)Tc-MIBI SPECT负荷MPI的糖尿病住院患者165例,根据负荷总积分(SSS)值分为0~7分组和≥8分组,比较两组患者的生存和MACEs发生情况。采用SPSS 17.0软件进行数据分析。根据数据类型分别采用t检验、秩和检验或X~2检验比较组间差异。结果两组患者男性比例、体质量指数(BMI)、左室射血分数(LVEF)、左室收缩末期内径(LVESD)、典型心绞痛、血运重建和室壁运动异常比例差异有统计学意义(P0.05)。两组间MACEs年发生率、因心绞痛住院率差异有统计学意义(P0.05)。Cox单因素回归分析结果表明室壁运动异常、SSS升高、冠心病家族史、既往血管重建治疗史、陈旧性心肌梗死史是MACEs的危险因素。Cox多因素回归分析结果表明冠心病家族史(RR=2.964,95%CI1.318~6.666;P=0.009)是MACEs的危险因素,其余变量无预测作用。Kaplan-Meier生存分析结果表明,SSS 0~7分组心脏事件年发生率为1%,SSS≥8分组心脏事件年发生率为4%。相比SSS 0~7分组,SSS≥8分组患者累积生存率偏低,差异有统计学意义(P=0.005)。结论应用~(99m)Tc-MIBI SPECT负荷MPI可对怀疑心肌缺血的糖尿病患者进行危险分层和预后评估,SSS≥8分的糖尿病患者危险分层为高危,建议血管重建治疗。     

Use of multislice CT for the evaluation of emergency room patients with chest pain: The so‐called “Triple rule‐out”

Recent advances in computed tomography (CT) technology have made high resolution noninvasive coronary angiograms possible. Multiple studies involving over 2,000 patients have established that coronary CT angiography (CCTA) is highly accurate for delineation of the presence and severity of coronary atherosclerosis. The high negative predictive value (>95%) found in these studies suggests that CCTA is an attractive option for exclusion of coronary artery disease in properly selected emergency department patients with acute chest pain. CT is also a well established and accurate tool for the diagnosis of acute aortic dissection and pulmonary embolism. Recent technical developments now permit acquisition of well‐opacified images of the coronary arteries, thoracic aorta and pulmonary arteries from a single CT scan. While this so called “triple‐rule out” scan protocol can potentially exclude fatal causes of chest pain in all three vascular beds, the attendant higher radiation dose of this method precludes its routine use except when there is sufficient support for the diagnosis of either aortic dissection or pulmonary embolism. This article provides an overview of CCTA, and reviews the clinical evidence supporting the use of this technique for triage of patients with acute chest pain. © 2008 Wiley‐Liss, Inc.     

Accuracy of multidetector computed tomography for detection of coronary artery stenosis in acute coronary syndrome compared with stable coronary disease: A CORE64 multicenter trial substudy

Background

Multi-detector computed tomography angiography (MDCTA) is a promising method for risk assessment of patients with acute chest pain. However, its diagnostic performance in higher-risk patients has not been investigated in a large international multicenter trial. Therefore, in the present study we sought to estimate the diagnostic accuracy of MDCTA to detect significant coronary stenosis in patients with acute coronary syndrome (ACS).

Methods

Patients included in the CORE64 study were categorized as suspected-ACS or non-ACS based on clinical data. A 64-row coronary MDCTA was performed before invasive coronary angiography (ICA) and both exams were evaluated by blinded, independent core laboratories.

Results

From 371 patients included, 94 were categorized as suspected ACS and 277 as non-ACS. Patient-based analysis showed an area under the receiver-operating-characteristic curve (AUC) for detecting ≥ 50% coronary stenosis of 0.95 (95% CI: 0.88–0.98) in ACS and 0.92 (95% CI: 0.88–0.95) in non-ACS group (P = 0.29). The sensitivity, specificity, positive and negative predictive values of MDCTA were 0.90(0.80–0.96), 0.88(0.70–0.98), 0.95(0.87–0.99) and 0.77(0.58–0.90) in suspected ACS patients and 0.87(0.81–0.92), 0.86(0.79–0.92), 0.91(0.85–0.95) and 0.82(0.74–0.89) in non-ACS patients (P NS for all comparisons). The mean calcium scores (CS) were 282 ± 449 in suspected ACS and 435 ± 668 in non-ACS group. The accuracy of CS to detect significant coronary stenosis was only moderate and the absence or minimal coronary artery calcification could not exclude the presence of significant coronary stenosis, particularly in ACS patients.

Conclusions

The diagnostic accuracy of MDCTA to detect significant coronary stenosis is high and comparable for both ACS and non-ACS patients.     

Epicardial adipose tissue is a robust measure of increased risk of myocardial infarction – a meta-analysis on over 6600 patients and rationale for the EPIC-ACS study

Background:Epicardial adipose tissue (EAT) surrounds the heart and the coronary vessels. EAT produces pro- and anti-inflammatory cytokines. Several studies have already documented the association of EAT and cardiovascular risk factors as well as coronary artery disease manifestations. Currently computed tomography (CT) is considered the gold standard for measurement of 3-dimensional volume of EAT. In addition, echocardiography might be an easy accessible alternative in particular in an emergency setting.Methods:We performed a metaanalysis of existing studies describing the differences of EAT in patients with and without myocardial infarction. We used established databases and were searching for “epicardial adipose tissue” or “pericardial adipose tissue” and “myocardial infarction”, “coronary events”, or “acute coronary syndrome”. We included over 6600 patients from 7 studies. Random effect models were calculated and all analyses were performed by using the Review Manager 5.3.Results:Patients with myocardial infarction had 37% (confidence interval [0.21-0.54], P value <.001)] higher measures of EAT compared to patients without myocardial infarction. Comparing studies using echocardiography vs CT for assessment of EAT thickness, similar relative differences in EAT with wide overlap of confidence intervals were observed (for echocardiography: 0.4 [0.04-0.76], for CT: 0.36 [0.16-0.57], P value <.001 for both).Conclusions:Patients with myocardial infarction have more EAT as compared to patients without myocardial infarction independently of the used imaging modality. Further prospective studies are needed to evaluate, how quantification of EAT in clinical routine can improve patients management.     

Implementation of technetium-99m MIBI SPECT imaging guidelines: optimizing the two day stress-rest protocol

Objectives. In a previous study in 460 patients, we found that in patients with suspected or known coronary artery disease undergoing stress-rest technetium-99m sestamibi (MIBI) SPECT myocardial perfusion imaging, rest SPECT imaging could be withhold in approximately 20% of patients because of a completely normal stress study. The present study was set up to evaluate the consequences of the implementation of this finding in a subsequent population of patients, and to set standards for the variety of protocols now used for MIBI SPECT imaging. Methods. Within a period of 4 months, 235 consecutive patients referred for MIBI SPECT scintigraphy were studied. All patients had stable cardiac chest pain and underwent symptom-limited exercise MIBI SPECT perfusion imaging. The stress SPECT images were reconstructed and evaluated immediately after acquisition of the images. In case of a clearly normal stress SPECT study, rest imaging was cancelled. Results. Twenty-six of 235 patients (11%) had a completely normal stress MIBI SPECT study and the rest SPECT imaging procedure could be subsequently cancelled. In 20 patients (9%) the stress SPECT was inconclusive, and in 189 (80%) of patients stress imaging was clearly abnormal. In the first month of the study, the nuclear medicine physicians and cardiologists would interprete only 6% of the stress images as normal, while this number increased to 13% after 9 weeks, with a mean of 11% for the whole investigation period of 4 months. Conclusion. In patients undergoing stress MIBI SPECT imaging, it was found justified to cancel rest MIBI SPECT imaging in at least 11% of patients because of a completely normal stress SPECT. As 9% of the images were inconclusive, the number of normal stress images could theoretically increase to 20% if reliable measures are taken to improve reading accuracy. This number is in close agreement with the number of normal stress studies previously reported by our institution and would lead to a considerable reduction of radiation dose, costs, and increased convenience for an important subset of patients.     

Detection of transient regional myocardial ischemia using body surface Delta map in patients referred for myocardial perfusion imaging—A pilot study

Background

The diagnosis of transient regional myocardial ischemia (TRMI) in patients presenting with stable chest pain is a challenge. Exercise Tolerance Test (ETT) is no longer recommended in most cases due to its flaws. Alternative tests are more expensive and less readily available. The BSM Delta map is an intuitive color display of digitally subtracted ST-segment shift derived from two 80-electrode BSM recordings at baseline and at peak stress, and has shown promise as a tool for detection of TRMI.

Objectives

The purpose of this pilot study was to assess the feasibility of BSM Delta map as a tool to detect TRMI using dobutamine stress ECG gated single-photon emission computed tomography myocardial perfusion imaging (MPI) as a reference.

Method

Forty consecutive patients were recruited who were referred for MPI with a history of angina-like symptoms. The BSM Delta map was derived from two 80-electrode body surface mapping system recordings carried out simultaneously with MPI at (a) baseline and (b) peak dobutamine stress. Standard 12-lead ECGs were also recorded at the same time points.

Results

The mean patient age was 68 ± 7.1 years, and 52% (21/40) were female. Using MPI as the reference the sensitivity of BSM Delta map was 82% (9/11) and specificity was 86% (25/29) (95% CI 0.688–0.992), positive likelihood ratio 5.93 (95% CI 2.29–15), negative likelihood ratio 0.21 (95% CI 0.06–0.75). The sensitive of the 12-lead ECG was 36% (4/11) and specificity was 76% (22/29) (95% CI 0.356–0.767), positive likelihood ratio 1.51 (95% CI 0.55–4.15), negative likelihood ratio 0.84 (95% CI 0.51–1.37). BSM Delta map is more sensitive and specific (McNemar's chi-square test p = 0.03 (95% CI, 0.448–0.924). The PPV and NPV for BSM Delta map were 69% (9/13) and 93% (25/27) respectively, compared with 36% (4/11) and 76% (22/29) for 12-lead ECG.

Conclusion

This pilot study confirms the feasibility of using Delta map in this context and suggests that it has promising diagnostic accuracy and is superior to the 12-lead ECG. It could potentially represent a clinically suitable screening tool for TRMI in patients presenting with stable chest pain, since it is near patient and requires little specialist training for acquisition and interpretation. A larger clinical study is now required.     

Cardiac mortality benefit of direct admission to percutaneous coronary intervention–capable hospital in acute myocardial infarction: Community registry–based study

Appropriate risk stratification and timely revascularization of acute myocardial infarction (AMI) are available in percutaneous coronary intervention (PCI) – capable hospitals (PCHs). This study evaluated whether direct admission vs inter-hospital transfer influences cardiac mortality in patients with AMI. This study was conducted in the PCH where the patients were able to arrive within an hour. The inclusion criteria were AMI with a symptom onset time within 24 hours and having undergone PCI within 24 hours after admission. The cumulative incidence of cardiac death after percutaneous coronary intervention was evaluated in the direct admission versus inter-hospital transfer groups. Among the 3178 patients, 2165 (68.1%) were admitted via inter-hospital transfer. Patients with ST-segment elevation myocardial infarction (STEMI) in the direct admission group had a reduced symptom onset-to-balloon time (121 minutes, P < .001). With a median period of 28.4 (interquartile range, 12.0–45.6) months, the cumulative incidence of 2-year cardiac death was lower in the direct admission group (NSTEMI, 9.0% vs 11.0%, P = .136; STEMI, 9.7% vs 13.7%, P = .040; AMI, 9.3% vs 12.3%, P = .014, respectively). After the adjustment for clinical variables, inter-hospital transfer was the determinant of cardiac death (hazard ratio, 1.59; 95% confidence interval, 1.08–2.33; P = .016). Direct PCH admission should be recommended for patients with suspected AMI and could be a target for reducing cardiac mortality.     

Low back pain: Influence of early MR imaging or CT on treatment and outcome - a randomized controlled study protocol

Objective:To establish whether early use of magnetic resonance imaging (MRI) or computed tomography (CT) influences treatment and outcome of patients with low back pain.Methods:This study will be implemented from March 2021 to March 2022 at Huzhou Traditional Chinese Medicine Hospital Affiliated to Zhejiang Chinese Medical University. The experiment was granted through the Research Ethics Committee of Huzhou Traditional Chinese Medicine Hospital Affiliated to Zhejiang Chinese Medical University (R609320987). Patients who have symptomatic lumbar spine disorders at presentation are eligible for the trial if there is clinical uncertainty about the need for imaging (MRI or CT). Patients are excluded who required immediate referral for imaging (those who had signs suggestive of serious abnormalities or disease or who required surgical intervention), who have undergone MR imaging or CT of the spine within 1 year, who do not need imaging, and who have pain of a nonspinal origin. The primary outcome measure is the Aberdeen Low Back Pain (ALBP) score. Other principal outcome measure is the Short Form 36.Results:Table 1 will show the quality of life outcome measures between groups.Conclusion:This study may guide the policy makers to develop an evidence-based protocol to assess the effect of early use of MRI or CT in the treatment of patients with low back pain.     

Effect of continued rt-PA administration on the residual stenosis after initially successful recanalization in acute myocardial infarction - a quantitative coronary angiography study of a randomized trial

Quantitative angiography was performed in 68 out of 123 patientstreated with intravenous rt-PA for acute myocardial infarction.At 90 min angiography, the median minimal cross-sectional areawas 1.11 mm² and the median percentage area stenosis was 80%.A percentage area stenosis greater than 70% was seen in 78%of the patients. Patients with a patent infarct related artery at the first angiogramwere randomized to receive subsequent infusions either of rt-PA+ heparin or placebo + heparin. There was a persistent trendof improvement in minimal lumen diameter and percentage diameterstenosis of the residual stenosis in the infarct related arteryin both treatment groups when re-examined 6–24 hours laterand at the time of hospital discharge. A reduction in ‘plaquearea’, the area between the detected and the referencecontours of the infarct related segment, was more frequentlyseen in patients receiving a second infusion of rt-PA than inpatients with no prolonged thrombolytic therapy (83% versus57%, P<0.025, chi square).