盐酸去甲乌药碱负荷99Tcm-MIBI心肌灌注显像在冠心病诊断中的价值

目的 评估盐酸去甲乌药碱(HG)负荷MPI对冠心病的诊断价值.方法 62例疑诊冠心病患者行HG负荷-静息99Tcm-MIBI MPI和CAG.以CAG结果为“金标准”,计算HG负荷显像诊断冠心病的灵敏度、特异性准确性、阳性预测值和阴性预测值.结果 以冠状动脉(简称冠脉)主支或其一级分支狭窄≥50％作为诊断标准,62例患者中CAG阳性38例(61.3％),阴性24例(38.7％);阳性者中单支病变24例,双支病变9例,三支病变5例.CAG阳性者中HG负荷显像异常22例;阴性者中HG负荷显像正常者22例.HG负荷显像诊断冠心病的灵敏度为57.9％(22/38),特异性为91.7％(22/24),准确性为71.0％(44/62),阳性预测值为91.7％(22/24),阴性预测值为57.9％(22/38).62例患者显像时发生不良反应22例(35.5％),但均能在短时内缓解,完成检查.结论 盐酸去甲乌药碱负荷99Tcm-MIBI心肌显像对冠心病的诊断价值尚可,不良反应较少;该药有望成为MPI新型负荷药物.     

盐酸去甲乌药碱注射液负荷核素心肌灌注显像诊断冠心病的有效性与安全性：Ⅱ期临床试验

目的评价盐酸去甲乌药碱注射液（HG）在负荷MPI诊断冠心病中的有效性和安全性。方法采用多中心、随机、开放、阳性药自身交叉对照设计研究。怀疑或已经确诊为冠心病的患者120例,每例均根据随机数字表按照不同顺序先后进行HG和腺苷负荷MPI。受试者负荷显像前后90d内行CAG检查,主要血管狭窄程度〉50％为冠心病。负荷MPI按心肌缺血严重程度与缺血范围分析,以CAG结果为“金标准”,比较HG和腺苷负荷MPI诊断冠心病的诊断效能及结果的一致性。同时进行试验的安全性评价,包括检查生命指征,血、尿常规、血生化指标等,以及记录不良反应。组间比较用两样本t检验、r检验或Fisher确切概率法,一致性分析采用Kappa检验。结果120例受试者中有11例未完成全部试验,不参加有效性分析,但参加安全性评价;另109例参加有效性分析。HG负荷MPI诊断冠心病的灵敏度为56．1％（32／57）,特异性为78．8％（41／52）,准确性为67．0％（73／109）,阳性预测值为74．4％（32／43）,阴性预测值为62．1％（41／66）;腺苷负荷MPI的诊断灵敏度为52．6％（30／57）,特异性为82．7％（43／52）,准确性为67．0％（73／109）,阳性预测值为76．9％（30／39）,阴性预测值为61．4％（43／70）。2药各对应诊断效能指标的差异均无统计学意义（r=0—0．2476,均P〉0．05）。HG负荷MPI诊断单支、双支和三支病变的灵敏度分别为29．6％（8／27）、64．7％（11／17）和100％（13／13）,腺苷负荷MPI相应结果分别为22．2％（6／27）、64．7％（11／17）和100％（13／13）。两药负荷MPI诊断LAD、LCX、RCA缺血的总一致性分别为95．41％（104／109）、97．25％（106／109）和97．25％（106／109）,Kappa值分别为0．8905、0．8420和0．8874。HG对受试者的收缩压几乎没有影响,舒张压有一定程度下降;心率可明显升高;血、尿常规和血生化等结果无异常改变。试验中共发生176例次与试验药物有关的不良反应,主要为胸闷、气短、心悸、头晕、头痛等,但症状轻微,停药后很快自行缓解。HG和腺苷负荷试验不良反应的发生率分别为69．2％（83／120）和77．5％（93／120）,差异无统计学意义（X2=2．1307,P〉0．05）。结论HG用于负荷MPI诊断冠心病的灵敏度和特异性与腺苷类似,安全性良好,具有临床应用价值。     

核素心肌灌注显像结合冠状动脉CT成像评价2型糖尿病功能相关冠状动脉病变的价值

目的 应用核素心肌灌注显像(MPI)结合冠状动脉CT成像(CTCA)评价2型糖尿病冠状动脉病变对心肌血供的影响,并与单一MPI或CTCA进行比较.资料与方法 纳入120例怀疑或确诊的冠状动脉粥样硬化性心脏病患者,根据其病史分为糖尿病组(n=58)和非糖尿病组(n=62),所有患者均行常规腺苷负荷/静息MPI和CTCA,并均于1个月内行冠状动脉血管造影术(CAG).以CAG、CAG联合MPI作为标准评价单一MPI、CTCA、MPI结合CTCA对“功能相关冠状动脉病变”的诊断效能.结果 糖尿病组MPI结合CTCA评价2型糖尿病冠状动脉病变与心肌血供关系的敏感性、特异性、准确性、阳性预测值和阴性预测值分别为93.58％、86.15％、90.80％、91.89％、88.89％.非糖尿病组MPI结合CTCA评价冠状动脉病变与心肌血供关系的敏感性、特异性、准确性、阳性预测值和阴性预测值分别为93.10％、91.43％、92.47％、94.74％、88.89％,均高于单一MPI或CTCA的诊断效能.结论 MPI结合CTCA评价2型塘尿病冠状动脉病变对心肌血供的影响,其诊断“功能相关冠状动脉病变”的效能明显高于单一影像技术.     

99Tcm-替曲膦心肌灌注显像诊断冠心病的临床价值

目的 评价99Tcm-替曲膦MPI对冠心病的诊断价值.方法 对73例临床怀疑冠心病的患者[男46例,女27例,年龄(61.16±12.95)岁],行99Tcm-TF MPI,第1天行静息显像,次日行运动或药物负荷显像.1周内行CAG,以其结果为“金标准”,计算99Tcm-TF MPI诊断冠心病的灵敏度、特异性和准确性等.结果 在73例患者中,43例CAG阳性,其中MPI阳性32例,阴性11例.单支病变27例,双支病变10例,三支病变6例.共65支病变血管,累及LAD 33支,LCX 16支,RCA 16支.30例CAG阴性,其中MPI阴性25例,阳性5例.99Tcm-TF MPI对冠心病诊断的灵敏度74.4％(32/43),特异性83.3％(25/30),阳性预测值86.5％(32/37),阴性预测值69.4％(25/36),准确性为78.1％(57/73).诊断单支、双支及三支病变患者的灵敏度分别为66.7％(18/27)、80.0％(8/10)和5/6.99Tcm-TF MPI诊断病变血管的灵敏度为67.7％(44/65),特异性为89.0％ (137/154).结论 99Tcm-TF MPI对冠心病有较好的诊断价值,是继99Tcm-MIBI之后又一优良的心肌灌注显像剂.     

99Tcm-替曲膦在冠心病诊断中的应用

目的 探讨99Tcm-替曲膦(TF)在CHD诊断中的应用价值.方法 回顾性分析2009年10月至2011年4月疑诊CHD并行99Tcm-TF或99Tcm-MTBI腺苷负荷-静息MPI的患者各40例,比较2种放射性药物心肌显像的心肺摄取比(H/L).行99Tcm-TF显像的患者显像前后3个月内均行CAG,以冠状动脉狭窄≥50％为标准计算99Tcm-TF显像对CHD的诊断效能.对99Tcm-TF及99Tcm-MIBI H/L间差异行配对t检验,率的比较行x2检验.结果 99Tcm-TF心肌静息及负荷显像H/L分别为6.73±1.21及6.94±1.69,99Tcm-MIBI显像的相应值分别为6.58±1.94及6.64±1.81,2种显像方法H/L间差异无统计学意义(=0.41和0.78,P均＞0.05),99Tcm-TF心肌静息及负荷显像H/L差异亦无统计学意义(t=0.69,P＞0.05). 40例患者中99Tcm-TF显像阳性24例(60.0％),对应病变血管45支,其中LAD 20支,LCX 11支,RCA 14支.CAG阳性23例(57.5％,23/40),对应病变血管42支(LAD19支,LCX 12支,RCA 11支).99Tcm-TF负荷-静息MPI的灵敏度、特异性、准确性、阳性预测值及阴性预测值分别为87.0％(20/23)、76.5％(13/17)、82.5％(33/40)、83.3％(20/24)及81.2％(13/16).以病变血管计,99Tcm-TF MPI对LAD、LCX及RCA血管病变诊断的灵敏度分别为89.5％(17/19)、83.3％(10/12)及90.9％(10/11);阳性预测值分别为85.0％(17/20)、90.9％ (10/11)及71.4％(10/14).99Tcm-TF显像对不同血管病变的灵敏度和阳性预测值差异均无统计学意义(x2=0.377和1.789,P均＞0.05).结论 从H/L可知,99Tcm-TF显像图像质量与99Tcm-MIBI显像接近;99Tcm-TF负荷-静息MPI是诊断CHD的可靠方法.     

腺苷负荷13N-NH3 PET心肌灌注显像结合冠状动脉CTA诊断冠心病

目的 评价腺苷负荷13N-NH3PET心肌灌注显像(MPI)与CT冠状动脉造影(CTA)相结合对提高冠心病(CAD)诊断准确性的临床应用价值.方法 对25例怀疑CAD的患者同时行腺苷负荷13N-NH3MPI及CTA,1个月内行导管法冠状动脉造影(CAG).结果 (1)25例患者共300个冠状动脉节段,CTA显示良好节段为263个,显示率(显示良好节段所占百分比)达87.7%.(2)25例患者CTA、MPI及CTA+MPI诊断CAD的灵敏度、特异性、准确性、阳性预测值及阴性预测值分别为82.1%(23/28),87.5%(14/16)及93.8%(15/16);93.2%(219/235),8/9及9/9;92.O%(242/263),88.0%(22/25)及96.0%(24/25);58.9%(23/29),93.3%(14/15)及100.0%(15/15);97.8%(219/224),8/10及9/10.结论 PET/CT实现了同机腺苷负荷"N-NH3PET心肌灌注显像与CTA相结合,提高了诊断CAD的准确性.     

99Tcm-替曲膦与99Tcm-MIBI心肌灌注显像诊断无症状心肌缺血的比较研究

目的 比较99Tcm-替曲膦(TF)与99Tcm-MIBI腺苷负荷-静息MPI在无症状心肌缺血(SMI)患者中的应用价值.方法 选择符合WHO冠心病诊断标准的Ⅰ、Ⅱ、Ⅲ型SMI患者,分别为122、112和72例,各型SMI均按完全随机法分为2组,分别行99Tcm-MIBI及99Tcm-TF腺苷负荷-静息MPI.306例患者的冠心病经心电图(46例)、动态心电图(219例)和CAG(41例)证实.比较2种显像方法的心肌缺血诊断灵敏度及原始图像质量.数据比较采用x2检验及方差分析.结果 按照心肌缺血诊断标准(负荷显像节段性放射性稀疏或缺损处静息显像时明显填充),99Tcm-MIBI和99Tcm-TF心肌显像诊断心肌缺血的灵敏度分别为:Ⅰ型:57.38％(35/61)和60.66％(37/61),x2=0.136,P＞0.05;Ⅱ型:69.64％(39/56)和64.29％(36/56),x2=0.363,P＞0.05;Ⅲ型:83.33％(30/36)和88.89％(32/36),x2=0.465,P＞0.05,3型SMI患者各2组间诊断心肌缺血的灵敏度差异均无统计学意义.原始图像质量方面,99Tcm-MIBI及99Tcm-TF显像图优(心肌影像清晰,无肝、肺、血本底干扰)者百分比分别为41.18％(63/153)和48.37％(74/153),x2=1.599,P=0.206;良(心肌影像尚清晰,但肝可见放射性,无明显血液本底)者百分比分别为45.10％(69/153)和34.64％(53/153),x2=3.489,p=0.062;中(心肌显影,肝放射性高,血液本底低)者百分比分别为13.72％(21/153)和16.99％(26/153),x2=0.628,P=0.428,差异均无统计学意义.图像总体质量良好,无不合格图像.注射99Tcm-TF者较注射99Tcm-MIBI者肝、肺放射性清除快,与心肌放射性摄取差异较大,对心脏下壁及心尖部显示影响较小,且至少缩短1h待检时间.结论 99Tcm-TF可获得与99Tcm-MIBI同等的心肌缺血诊断显像效果,且肝、肺清除快,图像质量较好,可有效缩短患者待检时问,有很好的应用前景.     

腺苷和运动试验201Tl心肌灌注显像诊断女性冠心病价值比较

目的 对比腺苷试验和运动试验201Tl心肌灌注显像诊断女性冠心病的价值.方法 采用随机对照研究,观察138例女性冠心病疑似病例,按随机数字表法将其分为腺苷试验组和运动试验组,每组69例,分别进行201Tl心肌灌注显像,并在1周内行冠状动脉造影检查.负荷心肌灌注显像按心肌缺血严重程度与缺血范围分析,冠状动脉造影按主要血管狭窄程度(>50%为冠心病)分析.以冠状动脉造影结果 为"金标准",比较腺苷和运动试验对女性冠心病的诊断灵敏度、准确性、阴性预测值和假阳性率.2组间比较采用χ2检验或确切概率法.结果 腺苷试验方法 对女性冠心病诊断的灵敏度、阴性预测值、准确性分别为88.2%(45/51)、72.7%(16/22)和88.4%(61/69);运动试验组分别为91.7%(44/48)、66.7%(8/12)和81.2%(52/64),二者间差异无统计学意义(χ2=0.571,0.714,0.249,P>0.05).腺苷试验组假阳性率低于运动试验组[11.1%(2/18)与50.0%(8/16),P=0.023].结论 对于女性冠心病患者,腺苷试验心肌灌注显像与运动试验心肌灌注显像同样有效,且腺苷试验的诊断假阳性率低.

Abstract：

Objective To compare the diagnostic value of adenosine and exercise stress myocardial perfusion imaging (MPI) for detecting coronary heart disease (CHD) in women. Methods One hundred and thirty-eight patients with CHD were randomly divided into two groups: adenosine stress group (n = 69)and exercise stress group (n = 69). All patients underwent myocardial SPECT evaluation. Coronary angiography (CAG), referred as "gold standard" , was performed in each patient within 1 week before or after MPI. The diagnostic value of the two stress MPI was compared with χ2 test or Fisher's exact test. Results In adenosine stress group, the sensitivity, negative predictive value and accuracy were 88.2% (45/51),72.7% (16/22), 88.4% (61/69), respectively, which were not significantly different from those of the exercise stress group (91.7% (44/48), 66.7% (8/12), 81.2% (52/64); χ2 =0. 571, 0. 714, 0.249, P >0.05). However, the false positive rate of adenosine stress (11.1%, 2/18) was significantly lower than that of exercise stress (50.0%, 8/16), P = 0.023. Conclusions Adenosine and exercise stress MPI have similar value for CHD diagnosis in women, however, adenosine stress MPI may have an advantage of low false positive rate.     

乳腺专用伽玛显像仪对乳腺癌的诊断价值

目的 通过与钼靶成像进行比较,探讨乳腺专用伽玛显像(BSGI)仪诊断乳腺癌的临床价值.方法 56例拟行手术的乳腺肿块女性患者分别进行BSGI和钼靶成像,2次检查间隔不超过15 d.对照术后病理结果,分别计算2种显像方法诊断乳腺癌的灵敏度、特异性、准确性、阳性预测值和阴性预测值,并采用配对x2检验比较检出率差异.结果 BSGI和钼靶成像诊断乳腺癌的灵敏度分别为92％ (34/37)和76％(28/37),特异性分别为84％(16/19)和74％ (14/19),准确性分别为89％ (50/56)和75％(42/56),阳性预测值分别为92％(34/37)和85％ (28/33),阴性预测值分别为84％(16/19)和61％(14/23),但两者诊断效能差异无统计学意义(X2=1.14,P＞0.05).BSGI准确诊断出6例钼靶成像漏诊的乳腺癌,该6例患者的乳腺组织均呈致密型.结论 BSGI对于乳腺癌(尤其是乳腺组织呈致密型者)的诊断具有一定的临床应用价值,弥补了钼靶成像的不足.     

CT血管造影在诊断功能相关性冠状动脉狭窄中的应用

目的以 SPECT 心肌灌注显像(MPI)为参考,评价 CT 血管造影检测功能相关性冠状动脉狭窄(FRCS)的诊断效能.资料与方法2005-11~2011-03在天津医科大学心血管病临床学院同期(30d 内)行冠状动脉 CT血管造影(CCTA)和 MPI 的504例可疑或确诊冠状动脉疾病患者,以 CCTA冠状动脉狭窄≥50%并伴有相应血管支配区域 MPI 灌注缺损作为诊断 FRCS的参考标准.以病例或血管为观察对象,分别计算 CCTA 冠状动脉狭窄≥50%或≥75%时检测 FRCS 的诊断效能.结果以病例为观察对象,CCTA 冠状动脉狭窄≥50%或≥75%检测 FRCS 的灵敏度、特异性、阳性预测值和阴性,预测值分别为67.2%和35.8%、84.7%和97.3%、40.2%和66.7%、94.4%和90.8%,差异均有统计学意义(P<0.05);以血管为观察对象,CCTA 冠状动脉狭窄≥50%或≥75%检测 FRCS 的灵敏度、特异性、阳性预测值和阴性预测值分别为70.2%和33.7%、95.4%和99.0%、42.9%和60.0%、98.5%和97.0%,差异均有统计学意义(P<0.05).结论 CCTA 具有较佳的排除 FRCS 的能力.当冠脉狭窄≥50%时,CCTA 虽然对 FRCS 检测灵敏度较高,但其阳性预测值相对较差.当冠脉狭窄≥75%时,CCTA 检测 FRCS 的阳性预测值有一定的提高.     

Stress MR imaging for evaluation of popliteal artery entrapment

The popliteal artery entrapment (PAE) syndrome has been recognized as a cause of arterial occlusion in young people. It is the result of an anomaly of the relationship between the popliteal artery and the gastrocnemius muscle. Eight young healthy volunteers (16 legs) and six patients (10 legs) with suspected PAE underwent magnetic resonance (MR) imaging. Gradient-echo images were obtained in axial planes with the leg at rest and during active plantar flexion against resistance. Imaging at rest allowed identification of PAE signs in only one leg, which had an anomalous medial course of the popliteal artery. In the other cases, only the stress technique was able to show signal loss in the popliteal artery due to muscular compression (two legs) or the presence of accessory muscle slip around the vessel (two legs), as confirmed at surgery. MR imaging is therefore a useful technique for the diagnosis of PAE because of its capability of combining information obtainable with other modalities.     

MR imaging of muscle and tender points in fibromyalgia

Fibromyalgia is a syndrome manifested by chronic, diffuse muscu-loskeletal aching and soreness, palpable muscle tender points, and other symptoms. Standardized clinical diagnostic criteria have recently been developed. Skeletal muscle has been postulated as the end organ in this disease. Biochemical, histologic, electromyographic, and conventional radiographic studies have demonstrated no definitive abnormality. This study sought to establish whether magnetic resonance (MR) imaging could demonstrate any abnormality in these patients. Eighteen patients were entered in the study, 14 of whom were able to complete their examinations. T1 -weighted, T2-weighted, gradient-echo, and STIR (short-tau inversion-recovery) sequences were performed in all patients, with selected patients examined with T1weighted, gadopentetate dimeglu-mine-enhanced sequences. The trapezius and suboccipital regions were imaged in patients who, clinically, had active fibro-myalgia. No abnormalities could be detected. The authors conclude that the conventional MR imaging used in this study was unable to depict any primary skeletal muscle abnormality in fibromyalgia.     

Uterine contractions: Possible diagnostic pitfall at MR imaging

A total of 206 nongravid patients with various gynecologic problems underwent pelvic magnetic resonance (MR) examinations that included both sagittal T2-weighted and contrast agent–enhanced T1-weighted images. MR images were retrospectively reviewed to identify changes in endometrial configuration on serial images obtained during the same MR examination. In 20 MR examinations (all in women of reproductive age), endometrial distortion due to myometrial bulging was noted on T2-weighted or contrast-enhanced T1-weighted images. It was absent on other MR images obtained at different times. Myometrial bulging exhibited low signal intensity in 18 examinations. The finding resembled adenomyosis or leiomyoma on T2-weighted or contrast-enhanced T1-weighted images. These results evidence the presence of transient myometrial bulging and transient low-intensity myometrium in the nongravid uterus. This phenomenon is thought to represent uterine contraction. Clinicians should be aware of the potential presence of transient low-signal-intensity myometrial bulging that could present diagnostic problems in the normal uterus.     

Controversies in cervical spine imaging in trauma patients

No area of emergency radiology has generated as much discussion in recent years as the subject of cervical spine imaging for trauma patients. This review will be in three parts. The first will examine the indications for cervical imaging and will focus on those factors that make patients at high risk or low risk for cervical injury. The second part will discuss the merits of radiography and computed tomography as the main screening diagnostic examination. In addition to the roles of each modality in the evaluation process, such factors as efficacy of diagnosis, time (duration) of study, and cost will be discussed. Finally, the third part will explore the methods currently employed to clear the cervical spine in comatose patients.Presented at the Annual Meeting of the American Society of Emergency Radiology, Las Vegas, Nevada, 22–25 October, 2003     

Brodie Abscess: MR imaging appearance in 10 patients

The magnetic resonance (MR) imaging features of Brodie abscess have not yet been fully evaluated. Ten patients with Brodie abscess, eight of long bone and two of vertebra, were studied with MR imaging. Long bone abscess had a characteristic “target” appearance with four layers: (a) a center with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR (short-inversion-time inversion recovery) images, (b) an inner ring isointense to muscle on T1-weighted images and with high signal intensity on T2-weighted and STIR images, (c) an outer ring hypoin-tense on all images, and (d) a peripheral halo hypointense on T1-weighted images. In six of eight cases, a soft-tissue mass was found. The two vertebral abscesses had a less specific appearance, with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR images. Only the peripheral halo was clearly identified in both cases.     

Adrenal tissue characterization with 0.5-T MR imaging: Value of T2*-weighted images

The authors investigated the value of magnetic resonance (MR) imaging at 0.5 T for distinguishing adrenal adenomas from adrenal metastases. The series included 23 adrenal adenomas (18 nonhyperfunctioning, five hyperfunctioning) and 23 adrenal metastases from various organs. Adrenal tumor–liver signal intensity ratios on T1-, T2-, and T2*-weighted images were calculated for adrenal tissue characterization. Adrenal adenomas were more precisely distinguished from adrenal metastases on T2*-weighted images (21 of 23, 91%) than on T2-weighted images (15 of 23, 65%). T1-weighted images were not useful for this distinction. In conclusion, T2*-weighted images were better than routine T2-weighted images for distinguishing adrenal adenomas from adrenal metastases. It can be postulated that the total signal intensity of adrenal adenomas, which contain some fat components, decreased on T2*-weighted images because of an out-of-phase effect.     

Pericerebellar fluid collections in infancy,sequelae of birth injury? A retrospective CT study

Summary Retrospective analysis of axial CT scans from 600 consecutive pediatric patients revealed 37 patients (6%) with abnormal low density pericerebellar spaces. Fourteen of these 37 patients (38%) were diagnosed as cerebellar atrophy, whereas 23 of the 37 patients (62%) were diagnosed as mass-like pericerebellar fluid collections. Detailed analysis of the morphology of these spaces suggests that the CT criteria proposed in this paper distinguish between (a) those low attenuation pericerebellar spaces that represent cisternal dilatation caused by cerebellar atrophy (Group I — Atrophy) and (b) those low attenuation pericerebellar spaces that represent low density mass-like collections of fluid which distort a relatively normal cerebellum (Group II — Collections). Analysis of the medical records of the patients in Group II — Collections reveal a high incidence of prematurity, developmental delay, difficult birth and head trauma, possibly indicating that such collections represent sequelae of birth.     

Localized proton MR spectroscopy of the brain in children

Small-voxel (3.0–8.0 cm³), magnetic resonance (MR) imaging–guided proton MR spectroscopy was performed in 54 patients (aged 6 days to 19 years) with intracranial masses (n = 16), neurodegenerative disorders (n = 34), and other neurologic diseases (n = 4) and in 23 age-matched control subjects without brain disease. A combined short TE (18 msec) stimulatedecho acquisition mode (STEAM) and long TE (135 and/or 270 msec) spin-echo point-resolved spatially localized spectroscopy (PRESS) protocol, using designed radio-frequency pulses, was performed at 1.5 T. STEAM spectra revealed short T2 and/or strongly coupled metabolites; prominent resonances were obtained from N-acetyl aspartate (NAA), choline-containing compounds (Cho), and total creatine (tCr). Lactate was well resolved with the long TE PRESS sequence. Intracranial tumors were readily differentiated from cerebrospinal fluid (CSF) collections. All tumors showed low NAA, high Cho, and reduced tCr levels. Neurodegenerative disorders showed low or absent NAA levels and enhanced mobile lipid, glutamate and glutamine, and inositol levels, consistent with neuronal loss, gliosis, demyelination, and amino acid neuro-toxicity. Preliminary experience indicates that proton MR spectroscopy can contribute in the evaluation of central nervous system abnormalities of infants and children.     

Dynamic contrast-enhanced MR imaging assessment of vascularized free fibular grafts

Magnetic resonance (MR) imaging may be a noninvasive method for assessing perfusion of vascularized bone grafts placed for treatment of avascular necrosis. One proximal femur of seven beagles was devascularized, with insertion of a vascularized fibular graft. MR imaging at 1 week (seven dogs) and 6 weeks (five dogs) after surgery included pre- and postcontrast spin-echo sequences, unenhanced twodimensional time-of-flight (TOF) vascular imaging, and dynamic gradient-echo imaging during infusion of gadolinium. Relative signal intensity values of selected regions obtained from the dynamic gradientecho images were plotted as percent enhancement versus time. In the operated hip, MR imaging did not show enhancement in six of seven femoral heads and greater trochanters at 1 week after surgery, with similar results after 6 weeks. MR imaging of fibular grafts 6 weeks after surgery showed an initial rapid increase in enhancement and a subsequent slower increase in five of five dogs, although no enhancement was seen in six of seven dogs at 1 week. These findings contrasted with a rapid initial increase in enhancement followed by slow decline in non-operated hips. Two-dimensional TOP imaging did not show the vascular pedicle of the graft in any dog. Findings of radionuclide bone scanning performed 1 week after surgery were consistent with devascularization of the operated femur and fibular graft. However, tetracycline distribution and histologic findings confirmed the viability of five of five grafts within the devascularized femurs 6 weeks after surgery. Thus, dynamic contrast-enhanced MR imaging at 6 weeks after surgery is valuable for assessing vascular bone graft perfusion, while similar imaging at 1 week may suggest otherwise.