Korean J Radiol.  2011 Apr;12(2):163-168. 10.3348/kjr.2011.12.2.163.

Usefulness of the CAD System for Detecting Pulmonary Nodule in Real Clinical Practice

• Song KD
• Chung MJ
• Kim HC
• Jeong SY
• Lee KS

• KMID: 1088560
• DOI: http://doi.org/10.3348/kjr.2011.12.2.163

Abstract

OBJECTIVE
We wanted to evaluate the usefulness of the computer-aided detection (CAD) system for detecting pulmonary nodules in real clinical practice by using the CT images.
MATERIALS AND METHODS
Our Institutional Review Board approved our retrospective study with a waiver of informed consent. This study included 166 CT examinations that were performed for the evaluation of pulmonary metastasis in 166 patients with colorectal cancer. All the CT examinations were interpreted by radiologists and they were also evaluated by the CAD system. All the nodules detected by the CAD system were evaluated with regard to whether or not they were true nodules, and they were classified into micronodules (MN, diameter < 4 mm) and significant nodules (SN, 4 < or = diameter < or = 10 mm). The radiologic reports and CAD results were compared.
RESULTS
The CAD system helped detect 426 nodules; 115 (27%) of the 426 nodules were classified as true nodules and 35 (30%) of the 115 nodules were SNs, and 83 (72%) of the 115 were not mentioned in the radiologists' reports and three (4%) of the 83 nodules were non-calcified SNs. One of three non-calcified SNs was confirmed as a metastatic nodule. According to the radiologists' reports, 60 true nodules were detected, and 28 of the 60 were not detected by the CAD system.
CONCLUSION
Although the CAD system missed many SNs that are detected by radiologists, it helps detect additional nodules that are missed by the radiologists in real clinical practice. Therefore, the CAD system can be useful to support a radiologist's detection performance.

Keyword

Computer-aided detection; Computed tomography (CT); Lung; Nodule

MeSH Terms

Colorectal Neoplasms/*pathology
*Diagnosis, Computer-Assisted
Female
Humans
Lung Neoplasms/*radiography/secondary
Male
Middle Aged
Retrospective Studies
Solitary Pulmonary Nodule/*radiography/secondary
*Tomography, X-Ray Computed

Figure

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  Fig. 1 57-year-old man who underwent transanal endoscopic microsurgery for rectal cancer four years before chest CT scan. Candidate lesion is marked (arrow) on captured image from computer-aided detection. This was actually branch of right superior pulmonary vein.

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  Fig. 2 55-year-old man who underwent low anterior resection for rectal cancer six months before chest CT scan. A. On axial CT image, small non-calcified lung nodule (diameter = 5.4 mm) is noted in right minor fissure (arrow). B. On captured image from computer-aided detection, nodule is marked as C1 candidate lesion (arrow). This nodule was detected by both computer-aided detection system and radiologist. C. On axial CT image performed one year later, nodule shows no interval change of size and shape (arrow). Note newly appeared malignant pleural effusion in left hemithorax.

• 

  Fig. 3 61-year-old woman who underwent right hemicolectomy for colon cancer one year before chest CT scan. A. On axial CT image, small lung nodule (diameter = 4.0 mm) is noted in right lower lobe (arrow). This non-calcified significant nodule was missed in official report. B. On captured image from computer-aided detection, same nodule is marked as C1, candidate lesion. C. On axial CT image performed four months later, nodule demonstrated interval increase in size (arrow). Metastatic adenocarcinoma was confirmed by video-assisted thoracoscopic surgery metastasectomy.

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