18F-FLT和18F-FDG评价食管癌细胞照射后超早期生物学反应

目的 比较18F-氟代脱氧胸腺嘧啶(18F-FLT)和18F-氟代脱氧葡萄糖(18F-FDG)在反映食管癌细胞受照后超早期生物学反应的差异.方法 将人食管癌Eca-109细胞分别接受5、10、15 Gy剂量X射线照射,照射后2、4、8h检测细胞对18F-FDG和18F-FLT摄取率的变化,以及细胞相对存活率和ATP表达情况的变化.结果 5 Gy照射后2、4h,细胞对18F-FDG摄取率与对照组相比分别减少了9.45％和16.4％,差异无统计学意义;但15 Gy照后2h,对18F-FDG摄取率却增加了26.5％(=3.04,P＜0.05),其余照射组对18F-FDG摄取率均有明显减少(F=25.75,P＜0.05).5 Gy照后2h,18F-FLT摄取率(3.65±0.41)％与对照组(4.00±0.42)％相比,差异无统计学意义,其余照射组对18F-FLT摄取率与对照组比较均有明显减少(F=33.93,P＜0.05).在5、10、15 Gy照后2、4、8h,各组细胞相对存活率差异无统计学意义.经不同剂量照射后,细胞对18F-FLT摄取率与ATP浓度之间的相关性(r=0.887,P＜0.05)优于18F-FDG与ATP浓度之间的相关性(r=0.622,P＞0.05).结论 18F-FDG和18 F-FLT两者均可反映食管癌细胞照射后超早期生物学反应,18F-FLT比18F-FDG能较好地反映食管癌细胞照射后超早期生物学反应.     

18F-FLT体外监测结肠癌细胞早期放射反应

目的 评价18F-脱氧胸腺嘧啶核苷（FLT）监测结肠癌细胞早期放射反应的作用.方法 应用四甲基偶氮唑蓝（MTT）检测并绘制SW480细胞受X线照射后生长曲线,光学显微镜下观察细胞形态变化.流式细胞仪检测照射后肿瘤细胞增殖周期的重新分布.分别于体外细胞以及肿瘤内检测照射前、后细胞摄取18F-FLT的变化.将18F-FLT（0.05±0.01）MBq加入培养液孵育细胞,分别于30,60,90,120 min测定细胞摄取18F-FLT的放射性.经荷瘤裸鼠尾静脉注射18F-FLT（1.90±0.85）MBq（0.25 ml）,60 min后处死动物,切除肿瘤与肌肉、肺、肝等,测定肿瘤与其他脏器摄取放射性比值变化.应用单因素方差分析进行统计学处理.结果 X线照射后,SW480细胞增殖受到明显的抑制,呈剂量依赖性.细胞形态随照射剂量的不同发生不同的变化.照射后细胞周期发生重新分布.10 Gy组,S期细胞百分比24 h从33.23%降至15.19%,72 h后降至12.44%.20 Gy组,S期细胞百分比24 h后从33.23%降至9.24%,72 h后降至5.43%.体外摄取实验发现,注射后60 min,SW480细胞摄取18F-FLT百分比为（5.21±1.60）%,10 Gy照射24 h后下降至（4.27±0.48）%,72 h降至（3.39±0.59）%.20 Gy组：照射后24 h,SW480摄取的放射性百分比下降至（3.41±0.58）%,72 h后降至（1.63±0.49）%.两照射组在72 h内分别下降了34.94%,69.72%（24 h∶F=8.253,P=0.009;72 h∶F=36.715,P＜0.001）.单位质量肿瘤组织摄取的18F-FLT随照射剂量的增加而逐渐降低（10Gy组：F=12.388,P=0.007;20 Gy组：F=16.744,P=0.004）.结论 18F-FLT在结肠癌细胞内的摄取可以快速反映照射治疗后的细胞变化,18F-FLT可能用于检测结肠癌放射治疗早期反应.     

18F-FLT细胞摄取率评价结直肠癌HCT116细胞早期放射反应

目的 观察不同剂量6MVX射线照射人结直肠癌细胞株HCT116后,体外细胞摄取18F-FLT的变化,分析18F-FLT用于早期预测肿瘤放射反应性的可行性.方法 测定1.0×105 ～1.5×106个细胞、培养36、60、84 h条件下,结直肠癌细胞株HCT116的18F-FLT摄取率.测定细胞经0、2、4、6、8 Gy6 MVX射线照射后,不同时间点(24、48、72 h)18F-FLT的细胞摄取率及细胞摄取抑制率;同时测定不同剂量照射后的细胞生长曲线、细胞增殖及细胞周期情况.结果 HCT116细胞对18F-FLT摄取率达(18.97 ±1.16)％.18F-FLT细胞摄取抑制率在照射2、4、6、8 Gy后24 h分别为(32.10±0.02)％、(54.46±0.04)％、(62.74±0.04)％和(65.81±4.81)％;18F-FLT细胞摄取抑制率与照射剂量呈正相关. 18F-FLT细胞摄取率与细胞周期S期比例呈正相关.结论 18F-FLT细胞摄取率可以早期反映人结直肠癌HCT116细胞株对放射的反应性.     

^18F-FLT和^18F-FDG PET显像早期评估荷肺腺癌小鼠放疗疗效

目的:比较18F-FLT和18F-FDG早期评估荷肺腺癌小鼠放疗疗效.材料和方法:24只T739荷肺腺癌小鼠随机分为18F-FLT和18F-FDG两组,各组再分为对照组和放疗组.放疗组接受20Gy的X线放射治疗后2天,各组小鼠经尾静脉注入18F-FLT和18F-FDG60min后行PET显像并井形探测仪测量活性分布.肿瘤增殖判定采用免疫组织化学方法测定PCNA.结果:放疗后肿瘤18F-FLT摄取较对照组明显降低(0.37±0.12%和1.25±0.19%,P<0.01),而18F-FDG摄取变化不明显.PET显像18F-FLTSUVmax值低于对照组,18F-FDG摄取变化不明显.肿瘤18F-FLT摄取与PCNA指数显著相关(r=0.8805),18F-FDG摄取与PCNA无相关性.结论:放疗后18F-FLT摄取降低较18F-FDG明显,与PCNA指数显著相关,因而18F-FLT是一种监测肿瘤治疗疗效的有前途的示踪剂.     

淋巴瘤细胞株Raji摄取~(18)F-氟脱氧葡萄糖和~(18)F-氟脱氧胸腺嘧啶核苷的体外实验研究

目的 研究测定人淋巴瘤细胞株Raji摄取~(18)F-氟脱氧葡萄糖(~(18)F-FDG)和~(18)F-氟脱氧胸腺嘧啶核苷(~(18)F-FLT)的方法并比较两者的差异.方法 在不同条件下测定淋巴瘤细胞株Raji对~(18)F-FDG和~(18)F-FLT的细胞结合率:细胞数量1×10~5～1×10~7/瓶;~(18)F-FDG和~(18)F-FLT的放射性活度1.85～29.6 kBq;反应时间20～120min;葡萄糖浓度0～11.1mmol/L.结果 每瓶1×10~7个细胞、加入3.7 kBq ~(18)F-FDG、葡萄糖浓度在0～2.78 mmol/L、作用100min,~(18)F-FDG细胞结合率达到(50.42±1.07)%;每瓶1×10~7个细胞、加入3.7 kBq ~(18)F-FLT、作用100min,~(18)F-FLT细胞结合率达到(59.48±0.77)%;~(18)F-FDG和~(18)F-FLT的细胞结合率之间具有统计学差异(F=1192.805,P<0.001).结论 Raji细胞与~(18)F-FDG的结合率与细胞数量、作用时间及葡萄糖浓度有关,与~(18)F-FDG的放射性活度无关;Raji细胞与~(18)F-FLT的结合率与细胞数量和作用时间有关,与~(18)F-FLT的放射性活度及葡萄糖浓度无关;同等条件下,Raji细胞对~(18)F-FLT的细胞结合率高于~(18)F-FDG.     

18F-FLT PET/CT与18F-FDG PET/CT在鼻咽癌诊断和分期中的应用比较

目的 通过与18F-FDG PET/CT显像对比,探讨18 F-FLT PET/CT检测鼻咽癌原发灶和颈部淋巴结转移灶的可行性.方法 12例初治且经病理确诊的鼻咽癌患者(年龄22～62岁)自愿进入该前瞻性临床研究.每位患者先行18F-FDG PET/CT检查,次日行18F-FLF PET/CT检查.至少有2位核医学科和放射科医师阅片,比较18F-FDG PET/CT和18F-FLT PET/CT图像,采用ROI技术计算鼻咽肿瘤、颈部淋巴结转移灶、正常组织对18F-FDG、18F-FLT的SUVmax、SUVmean和MTV.采用非参数Wilcoxon秩和检验比较组间摄取和MTV差异.结果 12例鼻咽癌患者病灶均明显摄取18F-FLT.18F-FLT PET/CT和18F-FDG PET/CT均可准确诊断该组病例,二者对原发灶和淋巴结转移灶的检测结果无明显差别.鼻咽癌病灶的18F-FDG和18F-FLT SUVmax分别为10.7±5.8和6.0±2.4,SUVmean分别为5.8±3.0和3.6±1.5;SUVmax和SUVmean组间差异均有统计学意义(Z=-2.589和-2.353,P均＜0.05),而 MTV在18F-FDG和8F-FLT PET/CT 2种显像方法之问的差异无统计学意义(15.9±9.2和18.1±11.1;Z=-0.786,P＞0.05).6例有颈部淋巴结转移灶患者的SUVmax、SUVmean和MTV在2种显像方法间差异均无统计学意义(8.5±6.2比6.4±2.5、5.3±4.2比3.8±1.4、6.5 ±4.8比6.0±4.4;Z=-0.734、-0.734和-0.674,P均＞0.05).18F-FLT在颞叶摄取(SUVmax 0.7±0.3)明显低于18F-FDG(SUVmax 8.3±2.7;Z=-3.062,P＜0.01),其对于原发灶颅内浸润显示较18F-FDG更清晰.结论 18F-FLT PET/CT在鼻咽癌原发灶和淋巴结转移灶的诊断效能与18F-FDG PET/CT相当,对于显示原发灶的颅底附近侵犯更有利,其临床应用值得进一步研究.     

^18F-FLT评价食管癌照射后早期生物学响应的实验研究

目的探讨^18F—FLT在评价食管癌细胞及其动物模型经X线照射后早期生物学响应中的应用价值。方法在体外以5、10和15Gyx线分别照射人食管癌细胞Eca-109,照射前及照射后2、4和8h检测细胞对^18F—FLT摄取率的变化、细胞相对存活率和ATP的表达情况。将24只荷食管癌裸鼠按随机数字表法分成4组：对照（未照射）组;10Gy照射后1、7及15d各1组,分别行^18F—FLT PET显像并测量肿瘤对^18F—FLT的摄取值（T／NT）的变化。显像后处死各组荷瘤裸鼠,取肿瘤组织,用免疫组织化学检测照射前、后瘤组织内细胞增殖核抗原（PCNA）及Ki67抗原的表达。组间差异比较用单因素方差分析及两独立样本t检验,数据间相关性分析用Pearson直线相关分析。结果照射前细胞对^18F-FLT摄取率为（4．00±0．42）％;经5、10、15Gy照射后2h分别下降至（3．65±0．41）％、（3．17±0．45）％和（2．53±0．28）％;照射后4h分别下降至（2．84±0．35）％、（2．58±0．39）％和（1．80±0．22）％;照射后8h分别下降至（2．71±0．23）％、（1．89±0．31）％和（1．44±0．20）％。与对照组比较,5、10、15q照射后2、4、8h,细胞相对存活率差异无统计学意义（F=4．02,P〉0．05）;ATP浓度下降明显,呈剂量依赖性。细胞受照后的^18F—FLT摄取率与ATP浓度呈正相关（r=0．89,P〈0．01）。^18F—FLTPET显像示裸鼠肿瘤呈高摄取,照射前T／NT为2．24±0．06,照射后1、7和15d分别下降至1．99±0．09、1．85±0．04和1．15±0．10。瘤组织对^18F-FLT的摄取值与PCNA、Ki67表达均呈正相关（r=0．83和0．88,均P〈0．01）。结论^18F—FLT在食管癌细胞及肿瘤内摄取的变化能较好地评价其照射后早期生物学响应,^18F—FLTPET有望用于监测食管癌照射后早期疗效。     

淋巴瘤细胞株Raji摄取18F-氟脱氧葡萄糖和18F-氟脱氧胸腺嘧啶核苷的体外实验研究

目的研究测定人淋巴瘤细胞株Raji摄取18F-氟脱氧葡萄糖（18F—FDG）和18F-氟脱氧胸腺嘧啶核苷（18F—FLT）的方法并比较两者的差异。方法在不同条件下测定淋巴瘤细胞株Raji对18F—FDG和18F—FLT的细胞结合率：细胞数量1×10^5-1×10^7/瓶;18F-FDG和18F—FLT的放射性活度1．85—29．6kBq;反应时间20—120min;葡萄糖浓度0～11．1mmol／L。结果每瓶1×10^7个细胞、加入3．7kBq18F．FDG、葡萄糖浓度在0—2．78mmol／L、作用100min,18F-FDG细胞结合率达到（50．42×1．07）％;每瓶1×10^7个细胞、加入3．7kBq 18F—FLT、作用100min,18F—FLT细胞结合率达到（59．48±0．77）％;18F—FDG和18F-FLT的细胞结合率之间具有统计学差异（F=1192．805,P〈0．001）。结论Raji细胞与18F—FDG的结合率与细胞数量、作用时间及葡萄糖浓度有关,与18F-FDG的放射性活度无关;Raji细胞与18F-FLT的结合率与细胞数量和作用时间有关,与18F-FLT的放射性活度及葡萄糖浓度无关;同等条件下,Raji细胞对18F-FLT的细胞结合率高于18F—FDG。     

18F－FLT microPET/CT显像评价沉默BRCA1表达对MDA－MB－231乳腺癌裸鼠模型的放疗增敏作用

目的探讨3′-脱氧-3′-18F-氟胸苷(FLT) microPET/CT显像评价沉默乳腺癌易感基因1(shBRCA1)表达对MDA-MB-231乳腺癌裸鼠模型的放疗增敏作用。方法将24只BALB/c裸鼠按随机数字表法分为4组(每组6只), 分别为阴性对照(NC)组、NC+放疗组、shBRCA1组、shBRCA1+放疗组, 分别于放疗前和4次放疗结束后24 h对裸鼠行18F-FLT microPET/CT显像。比较4组肿瘤治疗前后SUVmax的变化, 并分析治疗后各组肿瘤总增殖体积(TPV)。免疫组织化学法分析肿瘤组织细胞增殖核抗原Ki-67的表达情况。采用配对t检验、单因素方差分析、最小显著差异t检验和Pearson相关分析数据。结果成功构建了靶向BRCA1的乳腺癌细胞。放疗前, NC组、NC+放疗组、shBRCA1组和shBRCA1+放疗组的SUVmax分别为1.034±0.137、1.031±0.152、1.028±0.169和1.026±0.156, 差异无统计学意义(F=0.00, P=0.999);4次放疗结束后24 h, 4组的SUVmax分别为1.367±0.100、0...     

P-gp影响18F-FDG摄取的体外实验

目的 评价P-gp抑制剂维拉帕米(VER)及GF120918作用后,人乳腺癌细胞株Bcap37和Bcap37/多药耐药蛋白1(MDR1)的18F-FDG摄取变化;探讨18F-FDG摄取与P-gp表达之间的关系.方法 将Bcap37及Bcap37/MDR1细胞分别接种于6孔培养板上,1×106细胞/孔,分成对照组、VER组和GF120918组.分别将18F-FDG、VER及GF120918用不含FBS的RPMI 1640培养基配成37 kBq/ml18 F-FDG溶液、37 kBq/ml 18F-FDG+100 μnol/L VER溶液及37 kBq/ml 18F-FDG+50 μmol/LGF120918溶液,2种细胞株在上述溶液中孵育,分别于10、30、60及120 min分离细胞与培养基,用γ计数仪测量各试管内的放射性计数,计算Bcap37、Bap37/MDR1细胞的18F-FDG摄取率.2种细胞间及同种细胞不同处理组间18F-FDG摄取率比较行t检验.结果 在无抑制剂存在的情况下,孵育10 minBcap37/MDR1细胞中18F-FDG摄取率高于Bcap37细胞,其摄取率分别为(1.88±0.19)％和(1.37±0.18)％(t=7.832,P＜0.05);孵育60和120 min时Bcap37细胞对18F-FDG摄取率高于Bcap37/MDR1细胞,分别为(2.29±0.23)％、(2.34±0.15)％和(1.47 ±0.14)％、(1.53±0.22)％(t值分别为8.437和8.283,均P＜0.05).给予Bcap37/MDR1细胞VER或GF120918后,60和120 min时18F-FDG摄取率分别为(2.45±0.21)％、(2.46±0.25)％和(2.50±0.24)％、(2.48±0.27)％,较未给抑制剂时明显增加(t值分别为9.032、9.243与8.765、8.803,均P＜0.05).Bcap37细胞在有无抑制剂作用的情况下,18F-FDG摄取率无明显变化.结论 18F-FDG是P-gp的底物之一,Bcap37/MDR1细胞与Bcap37细胞间18F-FDG摄取率差异是由P-gp介导的外排作用引起的,18F-FDG可用于评价肿瘤细胞的P-gp功能.     

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.     

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     

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.     

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.     

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.     

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.