Limitations of an automated embolism segmentation method in clinical practice
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Published on: July 4, 2021
Ruifeng Wang1,2, Nan Yu1,2, Sheng Zhou1,3
1Department of Radiology, The First Affiliated Hospital of Medical School of Xi'an Jiaotong University, Xi'an, Shaanxi, China.
Purpose:
Automated pulmonary embolism (PE) segmentation is frequently used as a preprocessing step in the quantitative analysis of pulmonary embolism. Objective of this study is to analyze the potential limitation in automated PE segmentation using clinical cases.
Methods:
A database of 304 computer tomography pulmonary angiography (CTPA) examinations was collected and confirmed to be PE. After processing using an automated scheme, two radiologists classified these cases into four groups of A, B, C and D, which represent 4 different segmentation results namely, (1) entire pulmonary artery identified without motivation artifacts, (2) entire pulmonary artery identified with motivation artifacts, (3) part of the pulmonary artery identified, and (4) none of the pulmonary artery identified. Then, the possible failed reasons in PE segmentation were analyzed and determined based on the image characterization of the diseases and the applied CTPA scanning protocols.
Results:
In the study, 143 (47.0%., 30 (9.9%., 110 (36.2%. and 21 (6.9%. examinations were classified into groups A, B, C and D, respectively. Group C and D included the cases with failed segmentation. Fifteen failure reasons, including intrapulmonary abnormalities, extra-pulmonary abnormalities, diffuse pulmonary diseases, enlarged heart, absolute occluded vessels, embolism attached to artery wall, delayed scan time, skewed location, low scan dose, obvious artifact of superior vena cava, previous chest surgery, congenital deformities of the chest, incorrect positioning, missed images and other unknown reasons, were determined with corresponding case percentages ranging from 0.3%.o 9.2%.
Conclusions:
Automated segmentation failures were caused by specific lung diseases, anatomy varieties, improper scan time, improper scan dose, manual errors or other unknown reasons. Realization of those limitations is crucial for developing robust automated schemes to handle these issues in a single pass when a large number of CTPA examinations need to be analyzed.
Insights
Automated pulmonary embolism segmentation has limitations due to various factors like lung diseases and scan protocols. Understanding these failures is key to improving automated analysis of CTPA scans.
Area of Science:
- Radiology
- Medical Imaging Analysis
- Artificial Intelligence in Healthcare
Background:
- Automated pulmonary embolism (PE) segmentation is a crucial preprocessing step for quantitative analysis.
- Clinical case studies are essential for evaluating the limitations of automated PE segmentation algorithms.
Purpose of the Study:
- To analyze the potential limitations of automated pulmonary embolism segmentation.
- To identify failure reasons in automated PE segmentation using clinical data.
Main Methods:
- A database of 304 CTPA examinations with confirmed PE was analyzed.
- Two radiologists classified segmentation results into four groups (A-D).
- Failure reasons were determined based on image characteristics and CTPA protocols.
Main Results:
- Segmentation failed in 46.1% of cases (Groups C and D).
- Fifteen distinct failure reasons were identified, including intrapulmonary abnormalities, scan protocol variations, and artifacts.
- Failure reasons ranged from 0.3% to 9.2% in case percentages.
Conclusions:
- Automated segmentation failures stem from lung diseases, anatomical variations, and suboptimal scanning parameters.
- Recognizing these limitations is vital for developing more robust automated segmentation schemes.
- Improved automated analysis is needed for large-scale CTPA examination processing.
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