CT照片质量临床评价标准的研究

Clinical evaluation of quality criteria for CT film

CT照片的质量评价 ,通常是采用主观和经验的方法 ,在具体操作中有一定的困难。本文试图采用量化或半量化的方法 ,以期获得相对客观的评价标准。作者随机从各等级CT机型中 ,每一等级机型选择4～5家医院一共13家医院的颅脑、胸部、上腹部及腰椎4个部位的平扫CT片共400份 ,统一规定扫描方式与扫描参数。经过反复测算 ,将各部位的评审参数分解为解剖结构的显示、CT值测量、CT机伪影以及图像观感4个方面。同时又细分了有关的评审参数 ,并且根据各参数在图像质量中的重要性采取加以不同“权重”的方法。参数指标的评分又细分为AA到DD6级 ,也通过多次测算分别赋值。最后根据每张照片所获得的总分评定为甲、乙、丙及不及格4个等级 ,据此制定了“CT照片临床应用评审表”。评审结果基本符合北京市医院的实际情况 ,即北京市医院CT照片质量总体上是比较好的。各解剖部位的甲级片为31.1 %(胸部)～56.4 %(腹部) ,丙级片为7.9 %(颅脑)～15.6 %(胸部) ,不及格片仅占4.4 %(颅脑)。本文还讨论了各评审参数的必要性与评审中的问题。通过与年轻医师的双盲评审 ,认为本文提出的经过量化的评审标准对CT照片的评审很有用处 ,但仍有一定的主观性 ,评审工作必须由有经验的医师进行。

Purpose To determine the parameters of clinical evaluation and classification criteria for CT films quality. Materials and Methods: The films were produced from different grade CT apparatus in 5 of 13 hospitals randomly. The total number of films is 400 sheets that represent four anatomical positions of head, thorax, upper abdomen and lumbar spine, respectively. The clinical evaluation parameter of the film for every anatomical position is computed weightily, based on the four indexes of the film that describe the detection of anatomy construct, a measurement of CT value, the artifact from CT apparatus and the doctor's feeling on the film, respectively. A class from AA to DD marks every index of the film. Then according to the total indexes, the film is evaluated as excellent, good, pass and no pass. Results: For different anatomy position, the excellent films is from 31.1% (thorax) to 56.4% (abdomen), the qualified films is from 7.9% (head) to 15.6% (thorax) and 4.4% (head) film is not passed. Conclusion: The parameter of clinical evaluation of CT film quality is a semi-quantitative parameter. It is reasonable and useful in clinic, but not perfect, so the clinical evaluation of CT film is also evaluated by expert doctors simultaneously.