宫术宁联合戊酸雌二醇在绝经妇女取器的应用

目的观察宫术宁胶棒联合戊酸雌二醇在绝经后取器术中的应用价值。方法选择来我院要求取器的绝经妇女188例,随机分成两组,观察两组患者的取环成功率、宫颈扩张情况及对受术者的镇痛效果。结果观察组取器成功率、宫颈软化、扩张、镇痛及手术时间与对照组差别有统计学意义(P<0.05)。结论宫术宁胶棒联合戊酸雌二醇用于绝经后妇女取器,操作简便、宫颈扩张好、痛苦轻、安全有效,值得临床广泛推广。     

Reduced myocardial flow reserve in anatomically normal coronary arteries due to elevated baseline myocardial blood flow in men with old myocardial infarction

BACKGROUND: Decreased myocardial flow reserve (MFR) in angiographically normal coronary arteries in patients with old myocardial infarction (OMI) has been reported. METHODS AND RESULTS: To clarify factors for the reduced MFR in OMI and to compare them with those in angina pectoris (AP), baseline myocardial blood flow (MBF) and MBF during dipyridamole administration were measured with nitrogen 13 ammonia positron emission tomography, after which MFR was calculated for 13 men with AP, 18 men with OMI, and 15 age-matched male control subjects. MFR was compared among the 3 groups in segments perfused by nonstenotic arteries. Baseline MBF in patients with OMI was significantly higher than that in patients with AP and control subjects. MBF during dipyridamole administration in patients with OMI was significantly lower than that in control subjects. MFR in patients with AP was 2.50 +/- 0.91 (P <.05 vs control subjects [3.47 +/- 1.25]), and that in patients with OMI was 1.83 +/- 0.61 (P <.01 vs control and AP groups). Ejection fraction (EF) in patients with OMI was significantly decreased compared with that in patients with AP. However, there was no significant difference in the mean score of the individual risk factors between patients with AP and those with OMI. In the pooled data with AP and OMI, baseline MBF and EF were significant for the reduced MFR. CONCLUSIONS: MFR and EF in patients with OMI were significantly decreased compared with those in patients with AP. Increased baseline MBF and decreased EF were significant factors for the reduced MFR in patients with AP and OMI.     

Assessment of myocardial viability in dysfunctional myocardium by resting myocardial blood flow determined with oxygen 15 water PET

BACKGROUND: There is controversy about the role of decreased resting blood flow as the pathophysiologic correlate of hibernating myocardium. The aim of this study was an absolute quantification of volumetric myocardial blood flow (MBFvol) in dysfunctional myocardium with different viability conditions as defined by fluorine 18 deoxyglucose (FDG) positron emission tomography (PET) while taking into consideration the functional recovery after revascularization. The impact of MBFvol in the diagnosis of functional recovery was also investigated. METHODS AND RESULTS: Forty-two patients with severe coronary artery disease and dysfunctional myocardium underwent resting oxygen 15 water PET, as well as FDG PET and technetium 99m tetrofosmin single photon emission computed tomography, all attenuation-corrected. Relative FDG and Tc-99m tetrofosmin uptake (normalized to the segment with 100% Tc-99m tetrofosmin uptake), as well as MBFvol (myocardial blood flow multiplied by the water-perfusable tissue fraction to account for the flow to the entire segment volume), were determined in 18 myocardial segments per patient. Viability in dysfunctional segments (estimated by ventriculography) with reduced Tc-99m tetrofosmin uptake of 70% or lower was classified as viable (FDG >70%, mismatch) or nonviable (FDG < or =70%, match). Fifteen patients underwent revascularization and were followed up. Mismatch segments with improved function were classified as hibernating myocardium. Mean MBFvol in viable myocardium was slightly reduced (0.60 +/- 0.02 mL x min(-1) x mL(-1)) compared with that in normokinetic myocardium (0.64 +/- 0.01 mL x min(-1) x mL(-1)) (P = .036) and was significantly higher than in nonviable myocardium (0.36 +/- 0.01 mL x min(-1) x mL(-1)) (P < .001). Receiver operating characteristic analysis confirmed an FDG uptake greater than 70% as the optimal threshold to predict functional recovery (diagnostic accuracy [ACC], 76%). MBFvol in hibernating myocardium (0.62 +/- 0.04 mL x min(-1) x mL(-1)) was not significantly reduced compared with that in normokinetic myocardium (0.66 +/- 0.02 mL x min(-1) x mL(-1)) and was significantly higher than in persistently dysfunctional myocardium (0.51 +/- 0.04 mL x min(-1) x mL(-1)) (P < .05). The ACC of MBFvol greater than 0.40 mL x min(-1) x mL(-1) as the threshold to predict functional recovery was 61% but did not improve the accuracy of FDG PET by itself. CONCLUSIONS: In patients with severe coronary artery disease and dysfunctional myocardium, MBFvol as determined with O-15 water differs significantly between viable and nonviable myocardium as determined by FDG PET and is not significantly reduced in hibernating compared with normokinetic myocardium. Therefore chronically reduced resting blood flow appears unlikely to be the pathophysiologic correlate of the functional state of hibernation. However, MBFvol does not improve the ACC of FDG PET by itself.     

Quantification of myocardial blood flow and blood flow reserve in the presence of arterial dispersion: a simulation study.

Myocardial blood flow (MBF) can be quantified using dynamic T1-weighted MRI of diffusible tracers and a mathematical model of underlying vasculature. Quantification of MBF by means of T1- weighted MRI requires knowledge of the arterial input function (AIF). The AIF can be estimated from the left ventricular (LV) cavity. However, dispersion may occur between the LV and the tissue of interest because of the laminar blood flow profiles, branching of venules, and because of stenosis. To evaluate the influence of dispersion on the results of MBF quantification, a simulation study was performed. The dispersion was described as a convolution of the AIF with an exponential residue function. Synthetic tissue and AIF curves were analyzed and the derived parameters fit to the simulated parameters. The results show that an unaccounted dispersion may result in a systematic underestimation of MBF up to approximately 50%. Underestimation increases with increasing dispersion and with increasing MBF. Assuming equal dispersion at rest and during hyperemia, myocardial perfusion reserve (MPR) estimates are also susceptible to underestimation of approximately 20%. An unaccounted dispersion therefore can lead to systematic underestimation of both blood flow and perfusion reserve.     

Quantification of myocardial blood flow using model based analysis of first‐pass perfusion MRI: Extraction fraction of Gd‐DTPA varies with myocardial blood flow in human myocardium

For the absolute quantification of myocardial blood flow (MBF), Patlak plot‐derived K1 need to be converted to MBF by using the relation between the extraction fraction of gadolinium contrast agent and MBF. This study was conducted to determine the relation between extraction fraction of Gd‐DTPA and MBF in human heart at rest and during stress. Thirty‐four patients (19 men, mean age of 66.5 ± 11.0 years) with normal coronary arteries and no myocardial infarction were retrospectively evaluated. First‐pass myocardial perfusion MRI during adenosine triphosphate stress and at rest was performed using a dual bolus approach to correct for saturation of the blood signal. Myocardial K1 was quantified by Patlak plot method. Mean MBF was determined from coronary sinus flow measured by phase contrast cine MRI and left ventricle mass measured by cine MRI. The extraction fraction of Gd‐DTPA was calculated as the K1 divided by the mean MBF. The extraction fraction of Gd‐DTPA was 0.46 ± 0.22 at rest and 0.32 ± 0.13 during stress (P < 0.001). The relationship between extraction fraction (E) and MBF in human myocardium can be approximated as E = 1 ? exp(?(0.14 × MBF + 0.56)/MBF). The current results indicate that MBF can be accurately quantified by Patlak plot method of first‐pass myocardial perfusion MRI by performing a correction of extraction fraction. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.     

急性缺氧兔心肌区域血流量的变化及一氧化氮和腺苷的调节作用

目的探讨一氧化氮（NO）和腺苷在急性缺氧时心肌血流量调控中的作用。方法32只兔分为3组：Ⅰ组常氧对照组；Ⅱ组急性缺氧组；Ⅲ组急性缺氧＋NW-硝基-L-精氨酸（L－NA）组。后两组先在4000m高度停留30min，然后用戊巴比受纳麻醉。第Ⅲ组静脉滴入0．5％L－NA（0.3ml／min）20min。用放射性生物激球法测定心肌区域血流量和血管阻力。心肌组织中环磷酸鸟苷（cGMP）和腺苷含量分别用放免法和高效液相色谱仪测定。结果与对照组相比，急性缺氧组心肌区域血流量增加，心肌组织中cGMP和腺苷含量增高；急性缺氧＋L－NA组与急性缺氧组相比，心肌区域血流量降低，冠状血管阻力增加，心肌组织中cGMP含量降低，而腺苷含量则进一步增高。结论NO和腺苷均参与急性缺氧兔心肌血流量的调控。     

Fast mapping of myocardial blood flow with MR first-pass perfusion imaging.

Accurate and fast quantification of myocardial blood flow (MBF) with MR first-pass perfusion imaging techniques on a pixel-by-pixel basis remains difficult due to relatively long calculation times and noise-sensitive algorithms. In this study, Zierler's central volume principle was used to develop an algorithm for the calculation of MBF with few assumptions on the shapes of residue curves. Simulation was performed to evaluate the accuracy of this algorithm in the determination of MBF. To examine our algorithm in vivo, studies were performed in nine normal dogs. Two first-pass perfusion imaging sessions were performed with the administration of the intravascular contrast agent Gadomer at rest and during dipyridamole-induced vasodilation. Radiolabeled microspheres were injected to measure MBF at the same time. MBF measurements in dogs using MR methods correlated well with the microsphere measurements (R2=0.96, slope=0.9), demonstrating a fair accuracy in the perfusion measurements at rest and during the vasodilation stress. In addition to its accuracy, this method can also be optimized to run relatively fast, providing potential for fast and accurate myocardial perfusion mapping in a clinical setting.     

PET心肌灌注显像测定心肌血流量及冠状动脉血流储备的研究进展

PET心肌灌注显像可绝对定量测定局部心肌血流量（MBF）和冠状动脉血流储备（CFR）。由于显像剂半衰期短,允许在短时间内重复进行PET心肌灌注显像,获得静息态、冷加压试验和药物负荷试验等不同状态下的MBF,进而评价冠状动脉血管内皮依赖性和非依赖性的CFR功能。在早期诊断冠心病,准确诊断冠状动脉多支病变,评价微血管病变,早期检测冠状动脉内皮细胞功能异常及CFR功能的异常,估测预后,帮助临床治疗方案的制定以及检测疗效等方面,PET心肌灌注显像有重要的临床价值。该文将介绍PET心肌灌注显像相关知识及其在心血管领域的主要应用。     

Accurate myocardial T1 measurements: toward quantification of myocardial blood flow with arterial spin labeling.

In this study, we investigated a method for accurately measuring myocardial T(1) for the quantification of myocardial blood flow (MBF) with arterial spin labeling (ASL). A single-shot gradient-echo (GE)-based ASL sequence with an adiabatic hyperbolic secant inversion recovery pulse was modified to acquire a pair of myocardial T(1)'s within a breath-hold. A multivariable regression algorithm that accounted for the magnetization saturation effects was developed to calculate T(1). The MBF was then determined with a well-developed model. The accuracy of our T(1) calculation was first evaluated in a phantom, and then in six dogs for the MBF calculation, with (N = 4) and without (N = 2) coronary artery stenosis. In the phantom study, the accuracy of T(1) measured with a slice-selective inversion prepared pulse was within 2.5% of error. In healthy dogs, the MBF increased 2-5 times during vasodilation. In contrast, regional differences of MBF were well visualized in the stenotic dogs during vasodilation (perfusion reserve of 2.75 +/- 0.83 in normal myocardium, and 1.46 +/- 0.75 in the stenotic area). A correlation analysis revealed a close agreement in MBF between the ASL and microsphere (MS) in both healthy and stenotic dogs. In summary, the modified ASL technique and T(1) regression algorithm proposed here provide an accurate measurement of myocardial T(1) and demonstrate potential for reliably assessing MBF at steady state.     

In vivo assessment of myocardial blood flow in rat heart using magnetic resonance imaging: effect of anesthesia

PURPOSE: To assess the influence of isoflurane and pentobarbital anesthesia and the carrier gases on myocardial blood flow (MBF) in the rat heart in vivo. MATERIALS AND METHODS: MBF was quantified in vivo using arterial spin-labeling (ASL) magnetic resonance imaging (MRI). Left ventricular (LV) function was estimated during the same experiment using cine-MRI. Thirty-four male Wistar-Kyoto rats were divided in four groups, one anesthetized with isoflurane in oxygen:nitrous oxide mix (ISO), the three others with intraperitoneal pentobarbital, and breathing either room air (PB), oxygen:nitrous oxide (PB + N(2)O), or oxygen:nitrogen (PB + N(2)). RESULTS: MBF was significantly higher in the ISO and PB + N(2)O groups vs. PB and in ISO vs. PB + N(2), with the following respective MBF values: ISO, 5.9 +/- 1.1; PB, 4.0 +/- 0.8; PB + N(2)O, 5.1 +/- 1.4; and PB + N(2), 4.6 +/- 0.8 mL/g/minute, mean +/- SD. Ejection fractions were reduced by 10% in PB and PB + N(2)O rats vs. ISO rats. Cardiac output (CO) and index (CI) were 25 to 30% lower in all rats anesthetized with pentobarbital than with isoflurane. CONCLUSION: Isoflurane and nitrous oxide induce a higher MBF than pentobarbital. Isoflurane also induces a higher ejection fraction in healthy rats.     

绝经前后急性心肌梗死患者冠状动脉病变及相关危险因素研究

 目的 探讨绝经前后急性心肌梗死(acute myocardial infarction,AMI)患者冠状动脉病变及相关危险因素.方法 回顾性分析2005-01至2010-01解放军总医院收治的女性AMI患者246例,根据是否绝经及绝经年限进行分组,对冠状动脉造影结果及冠心病危险因素进行对比分析.结果 (1)绝经前组阻塞性病变的比例低于绝经后各组(P＜0.05);各组前降支病变比例均高于其他位置病变(P＜0.01);绝经年限与冠状动脉阻塞性病变的发生有相关性(P=0.024,OR=0.697).(2)绝经前组HDL-C平均水平高于绝经后各组(P＜0.05);绝经前组高尿酸血症者比例低于绝经后各组(P＜0.05);绝经前组有早发冠心病家族史者比例高于绝经后各组(P＜0.01);绝经年限与高尿酸血症有相关性(P=0.031,OR=0.767).结论 绝经前后女性AMI的冠状动脉病变及危险因素有所不同,应根据不同生理阶段女性冠心病的发病特点,做好女性冠心病的早期预防和诊治工作.     

Changes with age in left ventricular function and volumes at rest and postexercise in postmenopausal women

OBJECTIVES: In postmenopausal women, it has been reported that the plasma estrogen levels diminish immediately after menopause, and that this phenomenon affects left ventricular (LV) function and volumes. However, the effects of age on LV function and volumes for a relatively short period in the postmenopausal women remain to be established. Electrocardiographically gated-myocardial single-photon emission computed tomography (SPECT) has recently provided accurate estimations of perfusion, cardiac systolic and diastolic functions. We investigated the age-related changes in LV function and volumes in postmenopausal women using electrocardiographically gated-myocardial scintigraphy. METHODS: Twenty-two consecutive healthy postmenopausal women (mean age of 63.8 +/- 9.4 years, from 42 to 77 years) without cardiac disease underwent stress/rest technetium-99m tetrofosmin gated-myocardial SPECT with 16 frames per cardiac cycle at baseline and follow-up (1.0 +/- 0.3 years later). LV ejection fraction (LVEF) and LV volumes were calculated by QGS software. Fourier series were retained for the analysis of the volume curve. From this volume curve, we derived the following diastolic indices: peak filling rate (PFR) and time to PFR (TPFR). RESULTS: End-systolic volume index (ESVI) significantly decreased at postexercise (p = 0.02) and tended to decrease at rest (p = 0.06) from the baseline to the follow-up study. LVEF significantly increased at both postexercise (p = 0.01) and rest (p = 0.03) from the baseline to the follow-up study. The TPFR at rest tended to be prolonged from the baseline to the follow-up study (p = 0.07). The absolute increase in LVEF at postexercise tended to decrease with age [4.8% (50s) vs. 3.4% (60s) vs. 1.2% (70s)]. CONCLUSIONS: An age-related change in cardiac performance is apparent at an approximately 1 year follow-up in postmenopausal women. In particular, the increase in LV systolic function tends to show the greatest value in the 50s subjects among the 3 generations.     

Protocol for measuring myocardial blood flow by PET/CT in cats

Purpose  The aim of this study was to establish a protocol for measuring myocardial blood flow (MBF) by PET/CT in healthy cats. The rationale was its future use in Maine Coon cats with hypertrophic cardiomyopathy (HCM) as a model for human HCM. Methods  MBF was measured in nine anaesthetized healthy cats using a PET/CT scanner and ¹³NH₃ at rest and during adenosine infusion. Each cat was randomly assigned to receive vasodilator stress with two or three adenosine infusions at the following rates (μg/kg per minute): 140 (Ado 1, standard rate for humans), 280 (Ado 2, twice the human standard rate), 560 (Ado 4), 840 (Ado 6) and 1,120 (Ado 8). Results  The median MBF at rest was 1.26 ml/min per g (n = 9; range 0.88–1.72 ml/min per g). There was no significant difference at Ado 1 (n = 3; median 1.35, range 0.93–1.55 ml/min per g; ns) but MBF was significantly greater at Ado 2 (n = 6; 2.16, range 1.35–2.68 ml/min per g; p < 0.05) and Ado 4 (n = 6; 2.11, 1.92–2.45 ml/min per g; p < 0.05). Large ranges of MBF values at Ado 6 (n = 4; 2.53, 2.32–5.63 ml/min per g; ns) and Ado 8 (n = 3; 2.21, 1.92–5.70 ml/min per g; ns) were noted. Observed adverse effects, including hypotension, AV-block and ventricular premature contractions, were all mild, of short duration and immediately reversed after cessation of the adenosine infusion. Conclusion  MBF can be safely measured in cats using PET. An intravenous adenosine infusion at a rate of 280 μg/kg per minute seems most appropriate to induce maximal hyperaemic MBF response in healthy cats. Higher adenosine rates appear less suitable as they are associated with a large heterogeneity in flow increase and rate pressure product, most probably due to the large variability in haemodynamic and heart rate response.     

Comparison of myocardial blood flow and coronary flow reserve during dobutamine and adenosine stress: implications for pharmacologic stress testing in coronary artery disease

BACKGROUND: Mechanistic differences between pharmacologic stressors may offer different clinical benefits. Therefore the effects of dobutamine and adenosine on absolute myocardial blood flow (MBF) and coronary flow reserve (CFR) were compared. METHODS AND RESULTS: We divided 36 patients (mean age, 61 +/- 8 years) with coronary artery disease into 2 groups based on stenosis severity as follows: greater than 50% but less than 75% (n = 16) and greater than 75% (n = 20). In addition, 18 normal volunteers (mean age, 46 +/- 7 years) served as control subjects. Groups of equal sizes received either dobutamine or adenosine. MBF at rest and peak MBF were measured by use of positron emission tomography in territories subtended by the stenosis (ischemic) and remote myocardium (remote), whereas left ventricular MBF was used in control subjects. CFR was calculated as peak MBF divided by MBF at rest. CFR was significantly greater with adenosine than with dobutamine stress in control subjects and remote CFR. Ischemic CFR was blunted to a similar degree with each stressor. Therefore adenosine achieved flow heterogeneity across all coronary stenosis severities greater than 50%. However, dobutamine achieved flow heterogeneity only in the presence of a severe coronary stenosis greater than 75% despite provoking a greater ischemic stimulus. CONCLUSION: Adenosine stress demonstrated a higher sensitivity and dobutamine demonstrated a higher specificity with quantitative perfusion imaging. Therefore adenosine is superior for diagnostic perfusion imaging, whereas dobutamine is better suited in combination with visual imaging and in the functional assessment of a known coronary stenosis.     

Mapping myocardial perfusion with an intravascular MR contrast agent: robustness of deconvolution methods at various blood flows.

Evaluation of quantitative parameters such as regional myocardial blood flow (rMBF), blood volume (rMBV), and mean transit time (rMTT) by MRI is gaining acceptance for clinical applications, but still lacks robust postprocessing methods for map generation. Moreover, robustness should be preserved over the full range of myocardial flows and volumes. Using experimental data from an isolated pig heart preparation, synthetic MR kinetics were generated and four deconvolution approaches were evaluated. These methods were then applied to the first-pass T(1) images of the isolated pig heart using an intravascular contrast agent and rMBF, rMBV and rMTT maps were generated. In both synthetic and experimental data, the fit between calculated and original data reached equally good results with the four techniques. rMBV was the only parameter estimated correctly in numerical experiments. Moreover, using the algebraic method ARMA, abnormal regions were well delineated on rMBV maps. At high flows, rMBF was underestimated at the experimental noise level. Finally, rMTT maps appeared noisy and highly unreliable, especially at high flows. In conclusion, over the myocardial flow range, i.e., 0-400 ml/min/100g, rMBF identification was biased in presence of noise, whereas rMBV was correctly identified. Thus, rMBV mapping could be a fast and robust way to detect abnormal myocardial regions.     

Estimation of absolute myocardial blood flow during first-pass MR perfusion imaging using a dual-bolus injection technique: comparison to single-bolus injection method

PURPOSE: To compare the dual-bolus to single-bolus quantitative first-pass magnetic resonance myocardial perfusion imaging for estimation of absolute myocardial blood flow (MBF). MATERIALS AND METHODS: Dogs had local hyperemia of MBF in the left anterior descending (LAD) coronary artery (intracoronary adenosine). Animals (n = 6) had sequential single- and dual-bolus perfusion studies with microsphere determination of absolute MBF. Perfusion imaging was performed using a saturation-recovery gradient-echo sequence. Absolute MBF was by Fermi function deconvolution and compared to transmural, endocardial, and epicardial microsphere values in the same region of interest (ROI). RESULTS: Signal and contrast were significantly higher for the dual-bolus perfusion images. The correlation with MBF by microspheres was r = 0.94 for the dual-bolus method and r = 0.91 for the single-bolus method. There was no significant difference between MRI and microsphere MBF values for control or hyperemic zones for transmural segments for either technique. When the ROI was reduced to define endocardial and epicardial zones, single-bolus MR first-pass imaging significantly overestimated MBF and had a significantly larger absolute error vs. microspheres when compared to dual-bolus perfusion. CONCLUSION: Both single-bolus and dual-bolus perfusion methods correlate closely with MBF but the signal and contrast of the dual-bolus images are greater. With smaller nontransmural ROIs where signal is reduced, the dual-bolus method appeared to provide slightly more accurate results.