正电子发射断层显像评价衰老心肌葡萄糖代谢的变化

目的用正电子发射断层显像(positron emission computed tomography,PET)评估增龄对心肌葡萄糖代谢的影响。方法入选40例健康者,按照年龄分为成年组(40～59岁)和老年组(60～79岁),每组20例。所有研究对象进行静息心肌单光子发射计算机断层摄影(SPECT)和静息心肌PET,测定2组SPECT的左心室17节段静息总评分和各节段评分,与SPECT相匹配的各节段心肌的最大标准化摄取值(SUV_(max))。结果老年组与成年组左心室心肌SPECT的平均静息总评分差异无统计学意义(P0.05)。老年组前间隔基底部、下间隔中份、尖前壁和尖下壁静息评分较成年组明显增高(P0.05);老年组左心室各节段心肌~(18)F-脱氧葡萄糖(~(18)F-FDG)的总SUV_(max)较成年组明显增高(P0.01);老年组左心室多个节段的SUV_(max)较成年组明显增高,差异有统计学意义(P0.05,P0.01)。结论衰老可导致心肌对缺血敏感性加重的趋势;增龄可使心肌对~(18)F-FDP摄取和利用增加,可能是对衰老所致心肌缺血的自然保护性机制。

Evaluation of the glucose metabolism changes of aging myocardium by PET

Objective To evaluate the influence of aging on glucose metabolism of myocardium by positron emission computed tomography(PET).Methods Forty healthy volunteers were included and divided into the adult group(40 — 59 years old,n = 20) and the aged group(60 —79 years old, n = 20).All subjects received cardiac gated single photon emission computerized tomography (SPECT) and PET scan.The sum of rest scores of 17 segments of left ventricle and the rest scores of each segment by SPECT image were gained.The maximum standardized uptake value (SUV_(max)) of the 17 matched segments compared with gated SPECT were analyzed.Results There was no statistically significant difference between the average sum rest scores of the adult and the aged groups (P> 0.05).The rest scores of basal anteroseptal,mid inferoseptal,apical anterior and apical inferior segments from the aged group were significantly higher than those from the adult group by analysis (P < 0.05).The sum SUV_(max) of ~(18)F-deoxyglucose(~(18)F-FDG) of 17 segments from the aged group was significantly higher than that of the adult group (P <0.01). Most segments of the left ventricle of aged group had significantly higher SUV_(max) than that from the adult group (P <0.05,P <0.01).Conclusions Myocardial ischemia was detected during cardiac aging,increased glucose uptake and utilization might be the natural protective mechanism against ischemia in aging myocardium.