高压氧促进急性髓性白血病离体细胞凋亡和化疗药物增敏的初步研究

目的　用体外实验探讨高压氧 (HBO)对化疗药物体外诱导急性髓性白血病 (AML )细胞凋亡及对 AML细胞体外阿糖胞苷敏感性的影响。方法　 3种化疗药物——高三尖杉酯碱 (H)、阿糖胞苷 (A)、足叶乙甙 (V)分别作用于 AML患者的单个核细胞 ,一份加 HBO作测定组 ,另一份不加 HBO作对照组 ,观察各组凋亡细胞 ,并测定各组细胞活性、Bax/ bcl- 2积分比和 TUNEL阳性率及阿糖胞苷组 P-gp的表达。同时设无药加 HBO组和不加 HBO组以排除 HBO或其它因素对 AML细胞的影响。结果　3种化疗药物测定组具有典型凋亡特征的 AML细胞明显增多 ;Bax/ bcl- 2积分比 [测定组 :H :(2 .4 6±0 .4 4 ) ,A:(2 .0 6± 0 .89) ,V:(1.95± 0 .70 ) ;对照组 :H :(1.6 6± 0 .2 5 ) ,A:(1.34± 0 .2 8) ,V:(1.2 9±0 .2 5 ) ]明显高于对照组 (P<0 .0 5 ) ,TU NEL阳性率 [测定组 :H :(0 .397± 0 .0 8) ,A:(0 .377± 0 .0 6 ) ,V:(0 .4 0± 0 .0 6 ) ;对照组 :H:(0 .2 4 9± 0 .0 8) ,A :(0 .2 35± 0 .0 6 ) ,V:(0 .2 4 1± 0 .0 5 ) ]明显高于对照组 (P<0 .0 1) ,且 3种药物测定组与对照组细胞 Bax/ bcl- 2积分比之差、TU NEL阳性率之差的差异无显著性 (P>0 .0 5 ) ,阿糖胞苷组与对照组之间 P- gp的表达差异无显著性 (P>0 .0 5 )。结论　 H     

急性心肌梗塞静脉溶栓疗法的临床观察

我科于91年4月至95年2月用静脉血栓溶解疗法治疗急性心肌梗塞(AMI)27例,男性21例,女性6例,年龄40~70岁,平均58±7岁,用药后2小时内梗塞相关血管再通12例,再通组发病至溶栓开始的平均时间214±54Min,较未通组328±83min短,差异有显著意义(P<0.05),再通组治疗2h内发生快速心律失常7例,占73%,较未通组27%高(0.05相似文献   

CT灌注成像在乳腺良、恶性病变诊断中的应用

目的对乳腺病变CT灌注进行初步评价。方法22例乳腺疾病女性行乳腺CT灌注。其中纤维腺瘤1例(合并乳腺囊肿);其他良性病变5例;乳腺癌16例。采用电影模式(0.5s/r),120kV,60mA,5mm×4;注射流率4.0ml/s,延迟5s,扫描时间50s。利用GE公司Perfusion3体部灌注软件,分别测量血流量(BF)、血容量(BV)、平均通过时间(MTT)和表面通透性(PS),并进行统计学分析。结果乳腺癌组BF、BV、MTT、PS均值分别为(33.55±28.40)ml.min-1.100g-1、(5.60±3.08)ml/100g、(15.37±6.41)s和(18.71±10.42)ml.min-1.100g-1,对侧正常乳腺组BF、BV、MTT、PS均值分别为(10.36±9.44)ml.min-1.100g-1、(0.70±0.22)ml/100g、(13.55±7.27)s和(1.54±1.74)ml.min-1.100g-1,2组间BF、BV、PS均值差异有统计学意义(P<0.05),MTT均值差异无统计学意义(P>0.05)。纤维腺瘤BF、BV、MTT、PS均值分别为(62.57±19.62)ml.min-1.100g-1、(7.37±1.30)ml/100g、(11.24±3.34)s和(27.63±3.87)ml.min-1.100g-1,与乳腺癌组之间PS均值差异有统计学意义(P<0.05),BF、BV、MTT均值差异无统计学意义(P>0.05)。其他良性病变BF、BV、MTT、PS均值分别为(7.65±10.24)ml.min-1.100g-1、(1.23±0.97)ml/100g、(14.94±10.68)s和(1.81±1.72)ml.min-1.100g-1,与乳腺癌组之间BF、BV、PS均值差异有统计学意义(P<0.05),MTT均值差异无统计学意义(P>0.05)。结论CT灌注成像能反映乳腺病变的血液灌注特点,提供有价值的血流动力学信息,有助于乳腺良、恶性病变的鉴别诊断。     

老年原发性高血压患者BNP、hs-CRP与房颤关系的研究

目的探讨老年原发性高血压患者血清B型利钠肽(BNP)、高敏C反应蛋白(hs-CRP)水平与心房颤动之间的关系。方法对我院2008年10月—2011年10月连续诊治的老年原发性高血压患者209例,根据超声心动图(UCG)测量左室舒张末内径(LVEDD)、室间隔厚度(IVSD)、左室后壁厚度(LVPWD)、左室射血分数(LVEF)、左房内径(LA),计算左室质量指数(LVMI)。根据ECG将患者分为房颤组(AF组,105例)及无房颤组(NAF组,104例),测定两组患者的血清BNP、hs-CRP水平。结果 AF组中阵发性房颤48例,持续性房颤24例,永久性房颤33例。AF组患者的BNP[(198.66±118.85)ng/L与(86.37±66.96)ng/L]与LVMI[(127.19±28.04)g/m2与(83.70±17.23)g/m2]明显高于NAF组(P<0.01)。永久性房颤患者BNP明显高于阵发性房颤患者[(242.45±134.36)ng/L与(178.95±102.73)ng/L,P<0.05],而阵发性房颤、持续性房颤患者BNP无统计学差异(P>0.05);三组间hs-CRP均无统计学差异(P>0.05)。老年原发性高血压房颤患者BNP与患者LVMI、LA、房颤持续时间成正相关,与LVEF成负相关。Logistic回归分析表明,老年原发性高血压患者血清BNP水平升高,房颤的可能性增大。hs-CRP与房颤之间无相关性(P>0.05)。结论 BNP与老年原发性高血压房颤之间关系密切。BNP可作为老年原发性高血压左心室心肌肥厚的标志物。     

正常人内耳前庭、半规管及耳蜗的MRI测量

目的　利用高级快速自旋回波 (FASE)重T2 WI三维重建技术重建正常内耳膜迷路 ,建立内耳系统各主要结构的MRI测量正常值。方法　将 5 3例健康志愿者按年龄分为婴幼儿组、少年组、青年组、中年组和老年组 ,共 10 6只内耳分别行三维 ( 3D)FASE重T2 WI横断扫描。原始图像行最大强度投影 (MIP)重建 ,多角度旋转并测量内耳各主要结构的径线 ( 3个半规管高度和管径 ,耳蜗蜗高、底周直径和管径 ,前庭垂直径 ) ;行透视容积成像 (PVR)重建测量内耳液体容积。各观察指标就侧别、性别和年龄组间进行比较。结果　 ( 1) 3DFASE重T2 WI可清晰显示正常膜迷路结构和内听道内的神经 ;( 2 )内耳液体容积无年龄组间、侧别间差异 ,但男性 ( 0 2 42± 0 0 2 3 6)mm3与女性 ( 0 2 2 6±0 0 2 1)mm3间差异有非常显著性意义 (P <0 0 0 1)。 3个半规管高度、前庭垂直径无年龄组间、侧别间差异 ,但上半规管高度男性 ( 5 5 11± 0 62 6)mm与女性 ( 5 167± 0 3 5 7)mm间差异有非常显著性意义(P <0 0 0 1) ;水平半规管高度男性 ( 3 763± 0 495 )mm与女性 ( 3 44 6± 0 40 5 )mm间差异有非常显著性意义 (P <0 0 0 1) ;后半规管高度男性 ( 5 2 2 7± 0 5 47)mm与女性 ( 4 786± 0 5 0 0 )mm间差异有非常显著性意义 (     

正常成年男性脑干听觉诱发电位参量分析

目的测量并分析一组正常成年男性脑干听觉诱发电位各参量,为本实验室建立正常参考值。方法选择30-40岁正常成年男性34例,用KeypointⅡ型肌电图/诱发电位仪,进行脑干听觉诱发电位测试,记录各个参量数值。结果脑干听觉诱发电位各波形重复性良好,Ⅰ、Ⅲ、V波出现率均为100％,Ⅰ、Ⅲ、V波峰潜伏期分别为(1.77±0.14)、(3.88±0.19)、(5.82±0.22)ms,波幅分别为(O.24±O.14)、(O.24±0.10)、(O.35±O.13)μv,Ⅰ、Ⅲ、Ⅰ-v、Ⅲ一v峰间潜伏期分别为(2.13±0.12)、(4.05±O.18)、(1.92±O.12)ms。左右两侧无明显差异(P>O.05)。结论正常成年男性脑干听觉诱发电位各波重复性好,数据可靠,可作为本实验室的正常参考值使用。     

高脂饮食大鼠高住高练模型的建立

目的:建立高脂饮食致肥胖大鼠的高住高练0～4周动物模型,观察高住高练对肥胖大鼠的时序性影响。方法:出生21天离乳SD雄性大鼠280只,体重(42.7±4.7)g,随机选20只普通饲料喂养,其余260只高脂饲料喂养,自由饮食饮水。饲养10周后,随机选取普通饮食大鼠和高脂饮食大鼠各10只,称重、量身长,计算体重指数;取肾周和附睾脂肪垫称重计算脂体比;取血测血脂;从体重、体脂和血脂角度验证肥胖与否。验证肥胖后从高脂饮食组挑选出160只肥胖大鼠,进行适应性训练,确定常氧下训练强度为26 m/min。根据适应训练的情况保留130只大鼠进行正式实验,分成对照组,低住低练1、2、3、4周组,低氧安静1、2、3、4周组,高住高练1、2、3、4周组,保证各组间大鼠体重无显著性差异。用水平动物跑台进行耐力训练,持续运动1 h/d,6 d/w,1～4 w。低氧氧浓度为13.6%(约相当于3500 m高度)。根据血乳酸确定低氧下训练强度。结果:饲养10周后,普通饮食大鼠体重(425.1±54.2g)和身长(24.0±1.3cm)均显著(P<0.05)高于高脂饮食大鼠(362.7±37.9 g;22.3±0.7 cm),两组大鼠肾周脂肪和附睾脂肪重绝对值之间无显著差异,高脂饮食大鼠体重指数(320.39±13.55)和脂体比(0.99±0.15)%均高于普通饮食组(305.48±11.49,0.61%±0.29%),且具有显著性(P<0.05)和高度显著性(P<0.01)差异。高脂饮食大鼠胆固醇(1.91±0.26 mmol/L)、甘油三酯(0.59±0.25mmol/L)水平显著性(P<0.05)和高度显著性(P<0.01)高于普通饮食组(1.58±0.21 mmol/L、0.40±0.14 mmol/L),高脂饮食组大鼠低密度脂蛋白(0.20±0.04 mmol/L)与普通饮食组大鼠(0.15±0.03mmol/L)比较,高度显著性升高(P<0.01)。常氧26 m/min与低氧21 m/min运动后大鼠血乳酸较为接近。结论:(1)高脂饮食大鼠具有体脂比例、大鼠体重指数和血脂代谢紊乱的多重表现,可视为肥胖造模成功。(2)常氧下25～26 m/min的训练强度和13.6%低氧下20～21 m/min的训练强度相对于高脂饮食大鼠的代谢反应来说是相同的。     

正常高值血压42例心血管病危险因素分析

目的探讨正常高值血压患者的心血管病危险因素。方法根据《中国高血压防治指南(2005年修订版)》选择正常高值血压组42例及理想血压组50例,测量腰围、身高、体质量、坐位血压,计算体质量指数(BMI)、腰臀围比(WHR);测定空腹血糖(FPG)、总胆固醇(TC)、三酰甘油(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、尿酸(UA)、尿液微量白蛋白(MAU);并进行24 h动态心电图(Holter)、24 h动态血压(ABPM)监测。结果正常高值血压组与理想血压组相比,UA和MAU含量分别为(337.48±70.58)μmol/L比(257.63±69.42)μmol/L;(3.84±1.62)mg/L比(3.09±0.62)mg/L,差异有统计学意义(P<0.01)。正常高值血压组的WHR(0.83±0.08)与理想血压组(0.73±0.04)比较,差异有统计学意义(P<0.01)。两组的心率变异性(HRV)时域和频域参数比较差异有统计学意义(P<0.05)。两组的24 h收缩压变异系数(24 hSSD)分别为(17.3±2.3)%和(13.9±1.8)%;24 h舒张压变异系数(24hDSD)分别为(13.2±1.7)%和(10.3±1.7)%;非杓型血压的比例分别为26%和8%;收缩压负荷率(SBP-L)分别为(34±21)%和(12±10)%;舒张压负荷率(DBP-L)分别为(32±20)%和(11±9)%;差异有统计学意义(P<0.01)。比较两组的BMI、FPG、CHO、TG、HDL-C、和LDL-C差异无统计学意义(P>0.05)。结论与理想血压组比较,正常高值血压组的UA、MAU明显升高;迷走神经张力下降;血压变异性(BPV)、血压负荷和非杓型血压比例增高。     

骨质疏松老年妇女腰椎骨密度及结构的多层螺旋CT研究

目的评价容积性定量CT(vQCT)技术测量的腰椎骨密度(BMD)参数区分骨质疏松性椎体骨折与无骨折老年妇女的能力,对骨质疏松老年妇女腰椎结构与正常老年妇女进行比较。方法将有骨质疏松脊椎骨折的26例老年妇女归为第1组,选择年龄与其相匹配的无脊椎骨折的30例骨质疏松妇女归为第2组。应用多层螺旋CT(MSCT)对56例病人腰椎L1、L2椎体行容积扫描,在横断面影像中经传统的QCT法测量L1、L2小梁骨BMD(2D-TRAB)、整体骨BMD(2D-INTGL);在经计算机工作站行容积再现(VR)三维处理的影像中应用直方图功能测量L1、L2椎体整体骨BMD(3D-INTGL)、皮质骨BMD(3D-CORT)、小梁骨BMD(3D-TRAB)。双能X线吸收仪(DXA)测量参数为腰椎正位BMD(AP-SPINE)、腰椎正位表观BMD(BMAD)。比较2组老年妇女间上述7组的BMD值。另对10例2D-TRAB正常的老年妇女在VR像中测量L1椎体中部边长为20mm的正方体内骨小梁容积比值,并与在56例妇女中随机选取的10例的数值比较。结果DXA测量中AP-SPINE、BMAD在第1组妇女为(0·796±0·170)g/cm2、(272·7±27·7)mg/cm3,与第2组妇女(0·817±0·140)g/cm2、(249·5±26·5)mg/cm3之间差异无统计学意义;vQCT中第1组的2D-TRAB为(70·4±22·2)mg/cm3、2D-INTGL为(138·3±35·1)mg/cm3、3D-INTGL为(139·4±34·9)mg/cm3、3D-CORT为(133·8±26·9)mg/cm3、3D-TRAB为(69·9±18·6)mg/cm3,比第2组数值(89·1±21·8)mg/cm3、(170·6±34·5)mg/cm3、(180·5±28·2)mg/cm3、(163·2±27·5)mg/cm3、(83·8±17·1)mg/cm3下降18%~23%。10例骨质疏松老年妇女L1椎体骨小梁容积比值为(8·12±1·96)%,明显低于正常老年妇女的(39·13±2·15)%,差异有统计学意义(P<0·01)。结论MSCT中vQCT参数区分骨质疏松性椎体骨折与无骨折老年妇女的能力优于DXA,三维重组影像显示的骨质疏松老年妇女椎体骨小梁容积明显低于正常老年妇女。     

四脑室顶位置磁共振成像的临床定量研究

目的：用ＭＲＩ测量正常国人各性别、年龄组及Ｃｈｉａｒｉ畸形患者的第四脑室顶高距与水平距,以探讨其正常值范围及四脑室顶位置的发育规律。材料与方法：在颅脑（旁）正中矢状面ＳＥＴ１ＷＩ上测量３１７例正常国人和４２例Ｃｈｉａｒｉ畸形及可疑病人的第四脑室顶高距及水平距。正常组按性别、年龄分为１６组,每组２０例（７０岁以上女性组１７例）。ＭＲＩ应用１．０Ｔ全身ＭＲ机,用ｔ检验作统计分析。结果：四脑室顶高距女性为３０．０ｍｍ±１．９ｍｍ,男性为２９．６ｍｍ±２．９ｍｍ～３２．２ｍｍ±３．５ｍｍ;仅部分男性有显著年龄差异,但无显著性别差异。四脑室顶水平距男性为１１．０ｍｍ±１．５ｍｍ,女性为１０．６ｍｍ±１．３ｍｍ,无显著性别、年龄差异。Ｃｈｉａｒｉ畸形的四脑室高距明显低于正常人（Ｐ＜０．０１）,可疑组也明显低于部分年龄组正常男性（Ｐ＜０．０５）,而其水平距与正常各性别、年龄组的无显著差异（Ｐ＞０．０５）。结论：第四脑室顶位置有一定的生长发育规律,Ｃｈｉａｒｉ畸形常伴四脑室顶下移。     

Relation between exercise-induced ventricular arrhythmias and myocardial perfusion abnormalities in patients with intermediate pretest probability of coronary artery disease

The significance of exercise-induced ventricular arrhythmias (VAs) is largely dependent on the clinical characteristics of the studied population. The relation between exercise-induced VAs and myocardial perfusion abnormalities has not yet been evaluated in a homogeneous patient population with intermediate probability of coronary artery disease (CAD). We studied 302 patients (mean age 54±9 years, 152 men and 150 women) with intermediate pretest probability of CAD (range=0.25– 0.80, mean=0.43±0.20) by upright bicycle exercise stress test in conjunction with technetium-99m single-photon emission tomography (SPET) imaging. Exercise-induced VAs (frequent or complex premature ventricular contractions or ventricular tachycardia) occurred in 65 patients (22%). No significant difference was found between patients with and patient without VAs regarding the pretest probability of CAD (0.45±0.21 vs 0.43±0.20). Patients with exercise-induced VAs had a higher prevalence of perfusion abnormalities (52% vs 26%, P=0.002) and ischaemic electrocardiographic changes (31% vs 16%, P<0.05) compared to patients without VAs. A higher prevalence of perfusion abnormalities in patients with VAs was observed in both men (67% vs 35%, P<0.01) and women (38% vs 16%, P<0.05). However, the positive predictive value of exercise-induced VAs for the presence of myocardial perfusion abnormalities was higher in men than in women (67% vs 38%, P<0.05). The presence of abnormal myocardial perfusion was the only independent predictor of exercise-induced VAs (OR 2.2; 95% CI, 1.2–4.2) by multivariate analysis of clinical and stress test variables. It is concluded that in patients with intermediate pretest probability of CAD, exercise-induced VAs are predictive of a higher prevalence of myocardial perfusion abnormalities in both men and women. However, the positive predictive value of exercise-induced VAs for perfusion abnormalities is higher in men. Because of the underestimation of ischaemia by electrocardiographic changes, exercise-induced VAs should be interpreted as a marker of a higher probability of CAD. Received 15 September and in revised form 27 October 1999     

Dual input computed tomography perfusion in evaluating the therapeutic response of transarterial chemoembolization for hepatocellular carcinoma

Objective

To assess diagnostic role of multi-detector computed tomographic perfusion in evaluating the therapeutic response of trans-arterial chemo-embolization in hepatocellular carcinoma.

Combined quantitative supine-prone myocardial perfusion spect improves detection of coronary artery disease and normalcy rates in women

Background  We sought to determine the diagnostic performance of a recently developed combined supine-prone quantification algorithm for myocardial perfusion single photon emission computed tomography (MPS) for the detection of coronary artery disease (CAD) in women. Methods and Results  Consecutive MPS scans of women without known CAD and coronary angiography within 3 months of MPS (n ± 168) and with a low likelihood of CAD (n ± 291) were considered. Total perfusion deficit (TPD) was automatically derived for supine (S-TPD), prone (P-TPD), and combined prone-supine (C-TPD) data sets. The low-likelihood patients were grouped by bra cup size (A/B, n ± 102; C, n ± 101; and D, n ± 88). The areas under the receiver operator characteristic curves for S-TPD, P-TPD, and C-TPD were 0.84 ± 0.03, 0.88 ± 0.03, and 0.90 ± 0.03, respectively. C-TPD had a higher specificity than S-TPD and P-TPD for identification of CAD (stenosis <70%) without compromising sensitivity (61%, 76%, and 94% for S-, P-, and C-TPD, respectively; P > .0005 vs S-TPD and P > .05 vs P-TPD). Normalcy rates were higher for C-TPD than for S-TPD or P-TPD. Conclusions  Combined supine-prone quantitative MPS in women yields significantly increased specificity and normalcy rates without compromising sensitivity for the detection of CAD compared with standard analysis. (J Nucl Cardiol 2007;14:44–52.) Portions of this work were presented at the 52nd Annual Meeting of the Society of Nuclear Medicine, Toronto, Ontario, Canada, June 18–22, 2005. This work was supported in part by grants from Bristol-Myers Squibb Medical Imaging (North Billerica, Mass) and Astellas Healthcare (Deerfield, Ill).     

经右腋动脉选择性脑灌注在主动脉夹层手术中的应用

目的总结右腋动脉插管体外循环(ECC)、选择性顺行脑灌注在主动脉夹层手术中应用的初步经验。方法回顾性分析我院2005年1月—2008年7月采用深低温停循环(DHCA)加右腋动脉插管选择性顺行脑灌注(ASCP)手术治疗I型主动脉夹层10例。男8例,女2例。年龄24~63岁,平均(41.7±12.0)岁。升主动脉+全弓置换+降主动脉术中支架置入术5例,升主动脉+全弓置换2例,升主动脉+右半弓置换3例。结果本组主动脉阻断时间83~258min,平均(132.3±52.8)min。深低温停循环时间8~53min,平均(29.10±18.30)min,选择性脑灌注时间8~58min,平均(33.4±18.5)min。手术死亡2例,1例因术中出血、体外循环时间长不能脱机,1例因术后低心排和多脏器功能衰竭。术后暂时性脑损害2例,均治愈出院,无永久性脑损害发生。结论右腋动脉插管灌注和顺行脑灌注在主动脉夹层手术中可提供有效的脑保护,其操作简便、安全。     

Effects of respiratory cycle and body position on quantitative pulmonary perfusion by MRI

Purpose:

To evaluate the performance of lung perfusion imaging using two‐dimensional (2D) first pass perfusion MRI and a quantitation program based on model‐independent deconvolution algorithm.

Materials and Methods:

In eight healthy volunteers 2D first pass lung perfusion was imaged in coronal planes using a partial Fourier saturation recovery stead state free precession (SSFP) technique with a temporal resolution of 160 ms per slice acquisition. The dynamic signal in the lung was measured over time and absolute perfusion calculated based on a model‐independent deconvolution program.

Results:

In the supine position mean pulmonary perfusion was 287 ± 106 mL/min/100 mL during held expiration. It was significantly reduced to 129 ± 68 mL/min/100 mL during held inspiration. Similar differences due to respiration were observed in prone position with lung perfusion much greater during expiration than during inspiration (271 ± 101 versus 99 ± 38 mL/min/100 mL (P < 0.01)). There was a linear increase in pulmonary perfusion from anterior to posterior lung fields in supine position. The perfusion gradient reversed in the prone position with the highest perfusion in anterior lung and the lowest in posterior lung fields.

Conclusion:

Lung perfusion imaging using a 2D saturation recovery SSFP perfusion MRI coupled with a model‐independent deconvolution algorithm demonstrated physiologically consistent dynamic heterogeneity of lung perfusion distribution. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Dobutamine-atropine stress myocardial perfusion SPECT imaging in the diagnosis of graft stenosis after coronary artery bypass grafting

Objective  To assess the accuracy of dobutamine stress myocardial perfusion single photon emission computed tomographic imaging (SPECT) for the diagnosis of vascular stenosis after coronary artery bypass grafting (CABG). Background  Exercise thallium scintigraphy is a clinically useful method for the diagnosis of graft stenosis after CABG. Although dobutamine perfusion scintigraphy is an alternative method for the evaluation of patients with limited exercise capacity, its value in the diagnosis of vascular stenosis after CABG has not been studied. Methods  Dobutamine (up to 40 μg/kg/min)-atropine (up to 1 mg) stress test in conjunction with myocardial perfusion SPECT imaging (²⁰¹Tl or 99m technetium sestamibi [MIBI]) was performed in 71 patients (mean age 58±9 years, 57 men) with limited exercise capacity referred for evaluation of myocardial ischemia 3.7±3.5 years after CABG. Significant vascular stenosis was defined as ≥50% luminal diameter stenosis of a graft or a native nongrafted coronary artery and was predicted on the basis of reversible perfusion abnormalities. Results  Significant vascular stenosis was detected in 52 patients. Sensitivity, specificity, and accuracy of reversible perfusion defects at dobutamine SPECT for the overall diagnosis of vascular stenosis were 81%, confidence interval (CI) 72 to 90, 79%, CI 69 to 88, and 80%, CI 71 to 90, respectively. Significant vascular stenosis was detected in 73 arterial regions. Sensitivity, specificity, and accuracy of dobutamine SPECT for the diagnosis of regional vascular stenosis were 66%, CI 58 to 74, 83%, CI 76 to 89, and 74%, CI 67 to 81, respectively. Patients with multivessel stenosis had a higher number of ischemic segments (1.6±1.3 vs 1±1, P<.05) and ischemic perfusion score (3.2±2.7 vs 2.2±2.3, P<.05) than patients with single-vessel stenosis, respectively. Significant graft stenosis was detected in 67 graft regions. Sensitivity, specificity, and accuracy of dobutamine SPECT for the diagnosis of regional graft stenosis were 64%, CI 56 to 73, 85%, CI 78 to 91, and 74%, CI 66 to 82, respectively. Conclusion  Dobutamine stress myocardial perfusion SPECT imaging is a useful method for the diagnosis of significant vascular stenosis after CABG in patients with limited exercise capacity. Supported in part by the Department of Cardiology, Cairo University Hospital, Cairo, Egypt and by a grant from the NUFFIC, the Hague, the Netherlands.     

Comparison of myocardial perfusion estimates from dynamic contrast‐enhanced magnetic resonance imaging with four quantitative analysis methods

Dynamic contrast‐enhanced MRI has been used to quantify myocardial perfusion in recent years. Published results have varied widely, possibly depending on the method used to analyze the dynamic perfusion data. Here, four quantitative analysis methods (two‐compartment modeling, Fermi function modeling, model‐independent analysis, and Patlak plot analysis) were implemented and compared for quantifying myocardial perfusion. Dynamic contrast‐enhanced MRI data were acquired in 20 human subjects at rest with low‐dose (0.019 ± 0.005 mmol/kg) bolus injections of gadolinium. Fourteen of these subjects were also imaged at adenosine stress (0.021 ± 0.005 mmol/kg). Aggregate rest perfusion estimates were not significantly different between all four analysis methods. At stress, perfusion estimates were not significantly different between two‐compartment modeling, model‐independent analysis, and Patlak plot analysis. Stress estimates from the Fermi model were significantly higher (～20%) than the other three methods. Myocardial perfusion reserve values were not significantly different between all four methods. Model‐independent analysis resulted in the lowest model curve‐fit errors. When more than just the first pass of data was analyzed, perfusion estimates from two‐compartment modeling and model‐independent analysis did not change significantly, unlike results from Fermi function modeling. Magn Reson Med 64:125–137, 2010. © 2010 Wiley‐Liss, Inc.     

Age dependence of regional proton metabolites T2 relaxation times in the human brain at 3 T

Although recent studies indicate that use of a single global transverse relaxation time, T₂, per metabolite is sufficient for better than ±10% quantification precision at intermediate and short echo‐time spectroscopy in young adults, the age‐dependence of this finding is unknown. Consequently, the age effect on regional brain choline (Cho), creatine (Cr), and N‐acetylaspartate (NAA) T₂s was examined in four age groups using 3D (four slices, 80 voxels 1 cm³ each) proton MR spectroscopy in an optimized two‐point protocol. Metabolite T₂s were estimated in each voxel and in 10 gray and white matter (GM, WM) structures in 20 healthy subjects: four adolescents (13 ± 1 years old), eight young adults (26 ± 1); two middle‐aged (51 ± 6), and six elderly (74 ± 3). The results reveal that T₂s in GM (average ± standard error of the mean) of adolescents (NAA: 301 ± 30, Cr: 162 ± 7, Cho: 263 ± 7 ms), young adults (NAA: 269 ± 7, Cr: 156 ± 7, Cho: 226 ± 9 ms), and elderly (NAA: 259 ± 13, Cr: 154 ± 8, Cho: 229 ± 14 ms), were 30%, 16%, and 10% shorter than in WM, yielding mean global T₂s of NAA: 343, Cr: 172, and Cho: 248 ms. The elderly NAA, Cr, and Cho T₂s were 12%, 6%, and 10% shorter than the adolescents, a change of under 1 ms/year assuming a linear decline with age. Formulae for T₂ age‐correction for higher quantification precision are provided. Magn Reson Med 60:790–795, 2008. © 2008 Wiley‐Liss, Inc.     

Arterial spin labeling MRI study of age and gender effects on brain perfusion hemodynamics

Normal aging is associated with diminished brain perfusion measured as cerebral blood flow (CBF), but previously it is difficult to accurately measure various aspects of perfusion hemodynamics including: bolus arrival times and delays through small arterioles, expressed as arterial-arteriole transit time. To study hemodynamics in greater detail, volumetric arterial spin labeling MRI with variable postlabeling delays was used together with a distributed, dual-compartment tracer model. The main goal was to determine how CBF and other perfusion hemodynamics vary with aging. Twenty cognitive normal female and 15 male subjects (age: 23-84 years old) were studied at 4 T. Arterial spin labeling measurements were performed in the posterior cingulate cortex, precuneus, and whole brain gray matter. CBF declined with advancing age (P < 0.001). Separately from variations in bolus arrival times, arterial-arteriole transit time increased with advancing age (P < 0.01). Finally, women had overall higher CBF values (P < 0.01) and shorter arterial-arteriole transit time (P < 0.01) than men, regardless of age. The findings imply that CBF and blood transit times are compromised in aging, and these changes together with differences between genders should be taken into account when studying brain perfusion.     

Aging‐related changes of cognitive performance and stress regulation in high functioning elderly individuals

This article aims to analyse long‐term changes in cognitive performance and psychophysiological stress regulation in a specific sample of 10 young‐old (age at pre‐test: M ± SD = 63.2 ± 1.5) and 12 old‐old (age at pre‐test: M ± SD = 69 ± 2) persons possessing a high psychosocial status and a physically active lifestyle. Psychophysiological parameters were recorded prior to, during, and after the administration of a cognitive performance test battery. The measurements took place three times within a 6‐month period, and again 6 years later in a follow‐up test. Considering practice and habituation effects, findings provide no compelling evidence of an aging‐associated cognitive decline in attention, multiple choice reaction performance, and information processing speed, either in the young‐olds, or in the old‐olds. Furthermore, psychophysiological stress regulation showed no long‐term alteration regarding skin conductance level and heart rate. Based on these findings, it is assumed that psychosocial health and physical activity might contribute to the preservation of cognitive abilities and stress regulation into the 70s. Finally, this study demonstrated the significance of considering practice and habituation effects elicited through test repetitions in order to estimate long‐term effects.