|Year : 2018 | Volume
| Issue : 1 | Page : 128-132
Multislice spiral computed tomography in the differential diagnosis of ground-glass opacity
Jianqiang Yu1, Shiqiang Zhu1, Zufeng Ge1, Beilei Shen1, Yazhi Shen1, Chaojun Wang1, Xiong Fang1, Jian Dai2
1 Department of Radiology, Fenghua District Peoples' Hospital, Ningbo, PR China
2 Department of Radiology, Cixi People's Hospital, Zhejiang Province, PR China
|Date of Web Publication||8-Mar-2018|
Dr. Jian Dai
Department of Radiology, Cixi People's Hospital, Zhejiang Province 315300
Source of Support: None, Conflict of Interest: None
Objective: This study aimed to evaluate the value of multislice spiral computed tomography (CT) in differential diagnosis of benign or malignant pulmonary ground-glass opacity (GGO).
Materials and Methods: A total of 68 patients with pulmonary GGO who received surgical treatment in our hospital from January 2014 to January 2017 were retrospectively analyzed. Postoperative pathology showed that there were 22 cases of benign GGO and 47 cases of malignant GGO (adenocarcinoma). The diameter, maximum CT value, and mean CT value of benign and malignant GGOs were determined and compared. The clinical value of identifying benign or malignant GGOs with these indices was analyzed through receiver operating characteristic (ROC) curve.
Results: The mean GGO diameter, maximum CT value, and mean CT value in the benign group were significantly lower than those of in the malignant group, and the difference was statistically significant (P < 0.05). The diameter, maximum CT value, and mean CT value of GGO were applied to identify benign or malignant GGO: sensitivity was 60.87%, 69.57%, and 63.04%; and the specificity was 63.64%, 63.64%, and 81.82%; the cutoff values were 13.89 (mm), 26.18 (Hu), and 24.61 (Hu); and areas under the ROC curves were 0.66, 0.71, and 0.69, respectively.
Conclusion: The possibility of malignancy has been significantly increased for GGOs with a large diameter, high mean CT value and maximum CT value. Surgical treatment should be performed for this type of GGOs.
Keywords: Differential diagnosis, ground-glass opacity, multislice spiral computed tomography, pulmonary adenocarcinoma
|How to cite this article:|
Yu J, Zhu S, Ge Z, Shen B, Shen Y, Wang C, Fang X, Dai J. Multislice spiral computed tomography in the differential diagnosis of ground-glass opacity. J Can Res Ther 2018;14:128-32
|How to cite this URL:|
Yu J, Zhu S, Ge Z, Shen B, Shen Y, Wang C, Fang X, Dai J. Multislice spiral computed tomography in the differential diagnosis of ground-glass opacity. J Can Res Ther [serial online] 2018 [cited 2019 Nov 14];14:128-32. Available from: http://www.cancerjournal.net/text.asp?2018/14/1/128/226748
| > Introduction|| |
Lung cancer was one of the most common types of solid malignant carcinoma and exhibited high mortality. Lung cancer-related deaths accounted for 30% of the total deaths caused by all kinds of cancer. The mortality of this disease could be reduced with early diagnosis and intervention of lung cancer. The lung cancer death risk of the high-risk group could be reduced by 20% with low-dose spiral computed tomography (CT) examination annually. Many cases of pulmonary ground-glass opacity (GGO) have been detected because of the continuous development of CT examination technologies, such as the application of low-dose mass screening technology and high-resolution thin-slice CT (HRCT) examination, and improvement in CT machine performance (such as the application of multislice spiral CT). GGO can be classified according to its solid ingredients: pure GGO (pGGO; without solid ingredients) and mixed GGO (mGGO; containing solid ingredients). It was believed that most mGGOs were malignant. Therefore, understanding the CT characteristics of this malignancy was important for differential diagnosis, and improving the survival rate of lung cancers.
| > Materials and Methods|| |
Sixty-eight patients with pulmonary GGO who received operative treatment in our hospital from January 2014 to January 2017 were retrospectively analyzed. Among these patients, 22 and 46 were diagnosed with benign and malignant GGOs (adenocarcinoma), respectively. There were 28 males and 40 females, aged from 28 to 78 years (with the mean age of 59.2 ± 11.8). Of these patients, 39 were smokers and 29 were nonsmokers; and 37 cases with GGOs in the right lung and 31 cases with GGOs in the left lung.
The inclusion criteria were as follows: patients were examined with preoperative CT examination in our hospital, who were first diagnosed as GGO with clear pathological confirmation from postoperative pathology diagnosis. The exclusion criteria were as follows: mass was larger than 3 cm in diameter in the CT image, with regression after the follow-up anti-inflammatory treatment, or with metastasis of lung cancer according to the pathological results.
The CT was Aquilion 16-slice spiral CT (Toshiba Company, Japan). The three-dimensional reconstruction workstation system was Vitrea (version 3.0.1, Vital Images, Plymouth, MN, USA).
All cases of patients adopted a supine position with their arms lifted upward, and the head was first scanned in the Toshiba Aquilion 16-slice spiral CT. The scan involved the entire area of the apex of the lung to the base of the lung at both sides, including the chest walls and the armpits. Scan parameters were as follows: Aquilion 16; thickness, 1 mm; reconstruction thickness, 7 mm; screw pitch, 15 (0.98); FC, 52/01 (lung algorithm/soft tissue algorithm). Images with conventional thickness were sent to Vitrea workstation for post-processing. The parameters for cross-section thin-slice reconstruction were as follows: Aquilion 16 CT; slice thickness, l mm; interval, 0.8 mm; display field of view, 18–20 cm; Lung algorithm/soft tissue algorithm 52/01. The multiple-plane reconstruction was conducted as follows. The morphological features of the lesion were shown from the sagittal plane, coronal plane, and oblique plane with multiangle, in addition to conventional lung window and mediastinal window. The middle window also showed the lesion [Figure 1].
|Figure 1: Computed tomography scan of the GGO lesion (a) a ground-glass opacity with irregular shape in the lower lobe of the left lung; (b) ground-glass opacity in the right upper lobe of the right lung; (c) a ground-glass opacity lesion in the left lung; (d) a ground-glass opacity lesion in the left lung with irregular shape; (e) a ground-glass opacity lesion in the lower lobe of the left lung; (f) three-dimensional reconstruction of a ground-glass opacity lesion|
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Data were analyzed with SPSS version 20.0 Statistical Software (SPSS, Inc., Chicago, IL, USA). CT parameters, such as GGO diameter, maximum CT value, and mean CT value, were compared between benign and malignant GGO groups and analyzed using independent-sample t-test. Two-tailed P < 0.05 was considered as the statistical difference.
| > Results|| |
Comparison of general conditions of patients
The benign group consisted of 8 males and 14 females, with an average age of 49.2 ± 9.8 years; 9 smokers; and 11 cases of GGO in the right lung. The malignant group consisted of 20 males and 26 females, with an average age of 61.3 ± 12.1 years; 30 smokers; and 26 cases of GGO in the right lung. There was no statistical difference between the benign and malignant groups, in the proportion of male to female (P > 0.05), the proportion of smokers to nonsmokers (P > 0.05) and the GGO position (P > 0.05). Moreover, the age of the patients in the malignant group was significantly higher than those of in the benign group (P< 0.05) [Table 1].
|Table 1: The general information of patients in the benign and malignant group, n (%)/mean|
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Comparison of ground-glass opacity-related computed tomography parameters between the benign and malignant groups
Compared to that of in malignant GGO group, the mean diameter, maximum CT value, and mean CT value of GGO in the benign group were significantly lower, with statistically significant differences (P< 0.05) [Table 2] and [Figure 2].
|Table 2: Comparison of ground-glass opacity related computed tomography parameters in benign and malignant groups (x̄±s)|
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|Figure 2: Box plot of ground-glass opacity-related computed tomography parameters in benign and malignant groups (a) diameter comparison; (b) maximum computed tomography value comparison; (c) mean computed tomography value comparison|
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Diagnostic sensitivity, specificity, and area under the receiver operating characteristic curve
The sensitivity of GGO diameter, maximum CT value and mean CT value for identifying benign or malignant GGO was 60.87%, 69.57%, and 63.04%, respectively. Correspondingly, the specificity was 63.64%, 63.64%, and 81.82%; the cutoff values of differential diagnosis were 13.89 mm, 26.18 Hu, and 24.61 Hu [Table 3]; and the areas under the receiver operating characteristic curves were 0.66, 0.71, and 0.69, respectively [Figure 3].
|Table 3: Diagnostic sensitivity, specificity, and area under the receiver operating characteristic curve of computed tomography parameters|
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|Figure 3: The receiver operating characteristic curve of computed tomography parameters for malignant ground-glass opacity detection (a) ground-glass opacity diameter; (b) ground-glass opacity maximum computed tomography value; (c) ground-glass opacity mean computed tomography value|
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| > Discussion|| |
GGO, a common but nonspecific sign of lung cancer, has been an early manifestation of pulmonary interstitial or alveolar damage caused by pulmonary interstitial thickening, edema, fibrosis, neoplastic hyperplasia, partial alveolar collapse, normal breathing state, or increased blood volume of capillaries from the incompletely filled alveolar cavity or inflammation., GGO could be classified according to its solid components: PGGO and mGGO. The fibrosis or collapse of the alveoli with fibroblast proliferation could be observed in solid components of mGGO under the microscope.
Currently, most studies suggested that most of the mGGO cases were malignant. However, other scholars believed that the benign or malignant nature would be influenced by the amount of GGO components in mGGO. Clinical treatments for benign and malignant GGO were completely different. Therefore, the identification of the nature of GGO was particularly important. The present examination methods for GGO included contrast agent-enhanced examination (for nodules with diameter larger than 10 mm and specific rate of only 60%), 18F-fluorodeoxyglucose-positron emission tomography , (for nodules with diameter larger than 8 mm), percutaneous lung biopsy , (not applied as the first line) or bronchoscopic biopsy, which were almost ineffective for the GGO with diameter of <10 mm. In particular, the small diameter of a nodule leads to remarkable inaccuracy of these approaches. Furthermore, the presence of calcification or observation of signs in the edge was no longer qualitative indicator for benign or malignant small nodules. Thus, both thoracic surgeons and imaging physicians have currently focused on determining the suitable diagnosis method for pulmonary nodules.
Recently, with the continuous development of CT technology, especially the extensive application of multislice spiral CT and the improvement of post-image processing technology, multislice spiral CT played an important role in the identification of GGO nature., The GGO was manifested in HRCT as a relatively thin-density increased shadow in the lung with clearly shown local bronchial and vascular structures in the lesion. According to the amount of GGO: (i) pGGO; (ii) semisolid nodules; (iii) solid in the middle with GGO around (halo sign); (iv) mGGO with bronchial inflation sign in the solid part; (v) mGGO, but the proportion of GGO was <50%; (vi) completely solid nodules.
In this study, 68 patients with pulmonary GGO who received surgical treatment in our hospital from January 2014 to January 2017 were retrospectively analyzed. Postoperative pathology analysis showed 22 cases of neutral or benign GGO and 46 cases of malignant GGO (adenocarcinoma). Comparison of preoperative multislice spiral CT revealed that the mean GGO diameter, maximum CT value, and mean CT value in the benign group were significantly lower than those of in the malignant GGO group. The sensitivity for the application of the diameter, maximum CT value, and mean CT value of GGO to identify benign or malignant GGO was 60.87%, 69.57%, and 63.04%, respectively. Correspondingly, the specificities were 63.64%, 63.64%, and 81.82%; the critical values were 13.89 mm, 26.18 Hu, and 24.61 Hu; and the areas under the ROC curves were 0.66, 0.71, and 0.69, respectively. Therefore, this study suggested that the possibility of malignant GGO with a large diameter, mean CT value, and maximum CT value was significantly increased. This kind of GGO should be actively treated with a surgical operation.
With further GGO research, the diagnosis and treatment methods of GGO have developed to a certain degree. However, many controversies have still existed about GGO diagnosis and identification methods, especially for the nature of GGO., Consequently, no clear standard is available for GGO diagnosis and treatment. With the continuous development of medical treatment technology, as well as the improvement of imaging diagnosis and treatment technology, the nature of GGO will be accurately identified and effective clinical GGO treatment programs can be developed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]