A novel semi-automatic image processing approach to determine Plasmodium falciparum parasitemia in Giemsa-stained thin blood smears
A novel semi-automatic image processing approach to determine Plasmodium falciparum parasitemia in Giemsa-stained thin blood smears
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DOI：
10.1186/1471-2121-9-15
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发表时间：
2008-03-28
期刊：
影响因子：
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通讯作者：
Preiser, Peter R.
中科院分区：
文献类型：
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作者：
Le, Minh-Tam;Bretschneider, Timo R.;Preiser, Peter R.
背景资料：疟疾寄生虫血症通常被用作测量患者血液中寄生虫的数量和感染程度的重要指标。在显微镜下手动评估Giemsa染色的薄血涂片是繁重的，耗时的，并且容易出现人为错误。虽然自动评估可以克服这些问题中的一些，现有的方法是目前有限的，他们无法评估偏离选定的“标准”model.Results的情况下：在这项研究中，可靠的寄生虫血症计数，甚至低于标准的涂片和图像质量。通过与200多个样本涂片的手动评价进行比较，并与细胞重叠的复杂性相关，对结果进行评估。平均而言，相对于手动获得的寄生虫血症计数的平均值，估计误差小于1%。特别是从所提出的方法的结果通常是一个标准偏差内的计数提供了一个比较组的疟疾学家产生的相关性为0.97。变化主要发生在模糊的离焦图像，表现出较大程度的细胞重叠在集群的红细胞。评估也进行了精度和召回方面，并结合在F-措施提供的结果一般在92%至97%的范围内的各种涂片。在这种情况下，所观察到的精确度和召回率之间的权衡关系保证了稳定的结果。最后，有关的F-措施与细胞重叠的程度，表明高达50%的总细胞重叠可以容忍，如果涂片图像是良好的重点和涂片本身充分染色。结论：自动分析已被证明是可比的手动评估的准确性。此外，测试结果表明，所提出的基于比较的方法，通过利用不同的图像和颜色通道之间的相互关系，已成功地克服了大多数的固有的限制可能发生在样品制备和图像采集阶段。最终，这可以被视为开发低成本大规模筛查解决方案的机会。
Background: Malaria parasitemia is commonly used as a measurement of the amount of parasites in the patient's blood and a crucial indicator for the degree of infection. Manual evaluation of Giemsa-stained thin blood smears under the microscope is onerous, time consuming and subject to human error. Although automatic assessments can overcome some of these problems the available methods are currently limited by their inability to evaluate cases that deviate from a chosen "standard" model.Results: In this study reliable parasitemia counts were achieved even for sub-standard smear and image quality. The outcome was assessed through comparisons with manual evaluations of more than 200 sample smears and related to the complexity of cell overlaps. On average an estimation error of less than 1% with respect to the average of manually obtained parasitemia counts was achieved. In particular the results from the proposed approach are generally within one standard deviation of the counts provided by a comparison group of malariologists yielding a correlation of 0.97. Variations occur mainly for blurred out-of-focus imagery exhibiting larger degrees of cell overlaps in clusters of erythrocytes.The assessment was also carried out in terms of precision and recall and combined in the F-measure providing results generally in the range of 92% to 97% for a variety of smears. In this context the observed trade-off relation between precision and recall guaranteed stable results. Finally, relating the F-measure with the degree of cell overlaps, showed that up to 50% total cell overlap can be tolerated if the smear image is well-focused and the smear itself adequately stained.Conclusion: The automatic analysis has proven to be comparable with manual evaluations in terms of accuracy. Moreover, the test results have shown that the proposed comparison-based approach, by exploiting the interrelation between different images and color channels, has successfully overcome most of the inherent limitations possibly occurring during the sample preparation and image acquisition phase. Eventually, this can be seen as an opportunity for developing low-cost solutions for mass screening.