Powars D R, Conti P S, Wong W Y, Groncy P, Hyman C, Smith E, Ewing N, Keenan R N, Zee C S, Harold Y, Hiti A L, Teng E L, Chan L S
Department of Pediatrics, University of Southern California School of Medicine, Los Angeles, USA.
Blood. 1999 Jan 1;93(1):71-9.
Children with sickle cell anemia (SS) have an increased risk for cerebral vasculopathy with stroke (CVA) and cognitive impairment. The present study examines the extent to which adding positron emission tomography (PET) to magnetic resonance imaging (MRI) can improve the detection of cerebral vasculopathy. Whereas MRI has been the prime modality for showing anatomical lesions, PET excels at assessing the functional metabolic state through glucose utilization 2-deoxy-2 [18F] fluoro-D-glucose (FDG) and microvascular blood flow ([15O]H2O). Forty-nine SS children were studied. Among them, 19 had clinically overt CVA, 20 had life-threatening hypoxic episodes or soft neurologic signs, and 10 were normal based on neurological history and examination. For the entire sample of 49 subjects, 30 (61%) had abnormal MRI findings, 36 (73%) had abnormal PET findings, and 44 (90%) showed abnormalities on either the MRI or the PET or both. Of the 19 subjects with overt CVA, 17 had abnormal MRI (89%), 17 had abnormal PET (89%), and 19 (100%) had either abnormal MRI or PET or both. Among the 20 subjects with soft neurologic signs, 10 (50%) had abnormal MRI, 13 (65%) had abnormal PET, and 17 (85%) had abnormal MRI and/or PET. Six (60%) of the 10 neurologically normal subjects had abnormal PET. Among the 30 subjects with no overt CVA, 25 (83%) demonstrated imaging abnormalities based on either MRI or PET or both, thus, silent ischemia. Lower than average full-scale intelligence quotient (FSIQ) was associated with either overt CVA or silent ischemic lesions. Four subjects who received chronic red blood cell transfusion showed improved metabolic and perfusion status on repeat PET scans. In conclusion, (1) the addition of PET to MRI identified a much greater proportion of SS children with neuroimaging abnormalities, particularly in those who had no history of overt neurologic events. (2) PET lesions are more extensive, often bihemispheric, as compared with MRI abnormalities. (3) PET may be useful in management as a tool to evaluate metabolic improvement after therapeutic interventions, and (4) the correlation of PET abnormalities to subsequent stroke or progressive neurologic dysfunction requires further study.
患有镰状细胞贫血（SS）的儿童发生伴有中风（CVA）和认知障碍的脑血管病变的风险增加。本研究探讨了在磁共振成像（MRI）基础上增加正电子发射断层扫描（PET）在多大程度上能够改善对脑血管病变的检测。虽然MRI一直是显示解剖学病变的主要方式，但PET擅长通过葡萄糖利用2-脱氧-2 [18F]氟-D-葡萄糖（FDG）和微血管血流（[15O]H2O）来评估功能代谢状态。对49名患有SS的儿童进行了研究。其中，19名有临床明显的CVA，20名有危及生命的缺氧发作或轻微神经体征，10名根据神经病史和检查结果正常。在49名受试者的整个样本中，30名（61%）有异常的MRI表现，36名（73%）有异常的PET表现，44名（90%）在MRI或PET或两者上均显示异常。在19名有明显CVA的受试者中，17名有异常的MRI（89%），17名有异常的PET（89%），19名（100%）有异常的MRI或PET或两者。在20名有轻微神经体征的受试者中，10名（50%）有异常的MRI，13名（65%）有异常的PET，17名（85%）有异常的MRI和/或PET。10名神经功能正常的受试者中有6名（60%）有异常的PET。在30名没有明显CVA的受试者中，25名（83%）基于MRI或PET或两者显示有影像学异常，即无症状性缺血。低于平均水平的全量表智商（FSIQ）与明显的CVA或无症状性缺血性病变相关。4名接受慢性红细胞输血的受试者在重复PET扫描时显示代谢和灌注状态有所改善。总之，（1）在MRI基础上增加PET可发现更大比例的有神经影像学异常的SS儿童，特别是那些没有明显神经事件病史的儿童。（2）与MRI异常相比，PET病变范围更广，常为双侧半球性。（3）PET作为评估治疗干预后代谢改善的工具，可能在管理中有用，（4）PET异常与随后的中风或进行性神经功能障碍之间的相关性需要进一步研究。
