中华放射学杂志
中華放射學雜誌
중화방사학잡지
Chinese Journal of Radiology
2009年
7期
684-687
,共4页
刘玥%彭芸%李剑颖%曾津津%张祺丰
劉玥%彭蕓%李劍穎%曾津津%張祺豐
류모%팽예%리검영%증진진%장기봉
婴儿,新生%辐射剂量%体层摄影术,X线计算机
嬰兒,新生%輻射劑量%體層攝影術,X線計算機
영인,신생%복사제량%체층섭영술,X선계산궤
Infant,newborn%Radiation dosage%Tomography,X-ray computed
目的 评估降低扫描剂量对新生儿头颅64层MSCT图像的影响,计算最低剂量.方法 选择57例颅内出血患儿进行MSCT扫描,获得每例患儿后颅窝、基底节区及半卵圆中心3个层面实际扫描原始图像171幅.应用噪声添加工具,模拟扫描剂量减少25%、40%、50%和70%时的扫描情况,将相对应的不同模拟噪声添加到原始图像上,共获得5组855幅图像.2名放射科医师独立对图像质量进行评估,图像分析包括图像质量和图像噪声,即诊断接受率评分、图像主观噪声评分及客观噪声指数(noise index,NI).诊断接受率和图像主观噪声均采用5分制评分.图像噪声测量方法:分别在后颅窝、基底节区及半卵圆中心3个层面的小脑实质、丘脑及放射冠脑白质上放置ROI.测量NI值,然后计算平均值.应用Kappa法评价2名医师评定结果间的一致性,SPearman线性相关分析用于评估NI和诊断接受率评分之间的关系.结果 患者原始扫描剂量、模拟剂量分别减少25%、40%、50%、70%时图像诊断接受率评分分别为(4.47±0.51)、(3.96±0.33)、(3.21±0.45)、(2.92.±0.32)、(1.85±0.57)分,主观噪声评分(1.62±0.48)、(1.99±0.48)、(2.76±0.81)、(3.19±0.67)、(4.27±0.54)分,NI为1.90±0.19、2.17±0.20、2.44±0.25、2.68±0.28、3.37±0.39.2名医师的诊断接受率评分呈很好的一致性(K=0.860,P=0.017),图像噪声评分呈中度一致性(K=0.630,P=0.022).NI与诊断接受率评分之间呈正相关性(r=0.826,P=0.001).模拟扫描剂量减少40%,即管电流为107 mAs时,NI是2.44,诊断接受率评分是3.21,符合临床诊断需求.结论 在NI为2.44,模拟扫描剂昔减少40%时,可获得能满足临床诊断的图像.
目的 評估降低掃描劑量對新生兒頭顱64層MSCT圖像的影響,計算最低劑量.方法 選擇57例顱內齣血患兒進行MSCT掃描,穫得每例患兒後顱窩、基底節區及半卵圓中心3箇層麵實際掃描原始圖像171幅.應用譟聲添加工具,模擬掃描劑量減少25%、40%、50%和70%時的掃描情況,將相對應的不同模擬譟聲添加到原始圖像上,共穫得5組855幅圖像.2名放射科醫師獨立對圖像質量進行評估,圖像分析包括圖像質量和圖像譟聲,即診斷接受率評分、圖像主觀譟聲評分及客觀譟聲指數(noise index,NI).診斷接受率和圖像主觀譟聲均採用5分製評分.圖像譟聲測量方法:分彆在後顱窩、基底節區及半卵圓中心3箇層麵的小腦實質、丘腦及放射冠腦白質上放置ROI.測量NI值,然後計算平均值.應用Kappa法評價2名醫師評定結果間的一緻性,SPearman線性相關分析用于評估NI和診斷接受率評分之間的關繫.結果 患者原始掃描劑量、模擬劑量分彆減少25%、40%、50%、70%時圖像診斷接受率評分分彆為(4.47±0.51)、(3.96±0.33)、(3.21±0.45)、(2.92.±0.32)、(1.85±0.57)分,主觀譟聲評分(1.62±0.48)、(1.99±0.48)、(2.76±0.81)、(3.19±0.67)、(4.27±0.54)分,NI為1.90±0.19、2.17±0.20、2.44±0.25、2.68±0.28、3.37±0.39.2名醫師的診斷接受率評分呈很好的一緻性(K=0.860,P=0.017),圖像譟聲評分呈中度一緻性(K=0.630,P=0.022).NI與診斷接受率評分之間呈正相關性(r=0.826,P=0.001).模擬掃描劑量減少40%,即管電流為107 mAs時,NI是2.44,診斷接受率評分是3.21,符閤臨床診斷需求.結論 在NI為2.44,模擬掃描劑昔減少40%時,可穫得能滿足臨床診斷的圖像.
목적 평고강저소묘제량대신생인두로64층MSCT도상적영향,계산최저제량.방법 선택57례로내출혈환인진행MSCT소묘,획득매례환인후로와、기저절구급반란원중심3개층면실제소묘원시도상171폭.응용조성첨가공구,모의소묘제량감소25%、40%、50%화70%시적소묘정황,장상대응적불동모의조성첨가도원시도상상,공획득5조855폭도상.2명방사과의사독립대도상질량진행평고,도상분석포괄도상질량화도상조성,즉진단접수솔평분、도상주관조성평분급객관조성지수(noise index,NI).진단접수솔화도상주관조성균채용5분제평분.도상조성측량방법:분별재후로와、기저절구급반란원중심3개층면적소뇌실질、구뇌급방사관뇌백질상방치ROI.측량NI치,연후계산평균치.응용Kappa법평개2명의사평정결과간적일치성,SPearman선성상관분석용우평고NI화진단접수솔평분지간적관계.결과 환자원시소묘제량、모의제량분별감소25%、40%、50%、70%시도상진단접수솔평분분별위(4.47±0.51)、(3.96±0.33)、(3.21±0.45)、(2.92.±0.32)、(1.85±0.57)분,주관조성평분(1.62±0.48)、(1.99±0.48)、(2.76±0.81)、(3.19±0.67)、(4.27±0.54)분,NI위1.90±0.19、2.17±0.20、2.44±0.25、2.68±0.28、3.37±0.39.2명의사적진단접수솔평분정흔호적일치성(K=0.860,P=0.017),도상조성평분정중도일치성(K=0.630,P=0.022).NI여진단접수솔평분지간정정상관성(r=0.826,P=0.001).모의소묘제량감소40%,즉관전류위107 mAs시,NI시2.44,진단접수솔평분시3.21,부합림상진단수구.결론 재NI위2.44,모의소묘제석감소40%시,가획득능만족림상진단적도상.
Objective To determine the effects of dose reduction on multi-slice spiral CT(MSCT) of neonatal head and assess the lowest possible radiation for acceptable clinical images.Methods Fifty-seven newborns suspected intracranial hemorrhage were entered into the study and underwent MSCT scans.Original images at three anatomic levels (posterior fossa, basal ganglia, centrum semiovale) were collected and synthetic noise was added so as to simulate dose reductions of 25%, 40%, 50% and 70%, respectively by using the noise addition tool.A total of 855 image data sets were obtained for the 57 patients.Original and simulated dose-reduction scan images were analyzed.Image noise and image quality were assessed by two independent experienced pediatric radiologists using diagnostic acceptability score, subjective image noise score on a 5-peint scale and objective noise index.Image noise was measured by respectively placing region of interest (ROI) at cerebellum, thalamus and corona radiata of 3 different slices.And the noise index and mean value was calculated.The degree of inter-observer concordance was determined by Kappa statistical analysis.The Spearman statistical correlations between the noise index and diagnostic acceptability score were performed.Results On the images of original dose and simulated dose reductions of 25%, 40%, 50% and 70%, the diagnostic acceptability was 4.47±0.51, 3.96±0.33, 3.21±0.45, 2.92±0.32, and 1.85±0.57, respectively,the subjective image scores were 1.62±0.48, 1.99±0.48, 2.76±0.81, 3.19±0.67, and 4.27±0.54, respectively, the noise index were 1.90±0.19, 2.17±0.20.2.44± 0.25, 2.68±0.28, and 3.37±0.39, respectively.The two radiologists had good intembserver agreement for diagnostic acceptability (K=0.860, P=0.017) and for image noise scoff ng (K=0.630, P=0.022).There was significant statistical correlation between image noise index and diagnostic acceptability (r= 0.826,P=0.001).At 40% dose reduction to the standard protocol, the noise index was 2.44 and the image quality score was 3.21 which were considered clinically acceptable.Conclusion The study revealed that acceptable imagos could be obtained with mean noise index of 2.44 and 40% dose reduction.
