Improvement of CT Target Scanning Quality for Pulmonary Nodules by PDCA Management Method

Radiology Department, Ninghai First Hospital Medicare and Health Group, Ningbo, China College of Information Engineering, Huzhou University, Huzhou, China College of Digital Technology and Engineering, Ningbo University of Finance & Economics, Ningbo, China College of Electronics and Computer, Zhejiang Wanli University, Ningbo, China Department of Nursing, -e First People’s Hospital of Huzhou, Huzhou, Zhejiang, China


Introduction
Delivering improvements in the quality and safety of clinical diagnosis of pulmonary nodules remain an international challenge [1]. In recent years, quality improvement (QI) methods such as plan-do-check-act (PDCA) cycles [2] have been used in an attempt to drive such improvements. CT target scanning is a key process during clinical diagnosis of pulmonary nodules, and the image quality of CT target scanning of pulmonary nodules is one of the major factors affecting the radiologist's judgment of patients' condition and directly related to the doctor's clinical treatment and patient's rehabilitation [3]. CT target scanning of pulmonary nodules includes the following steps: scanning appointment process, saving and utilization of scanning results, operation specification of doctors in the diagnosis group, respiratory training of patients, and setting of scanning range, which involves the cooperation of registrants, technicians, diagnostic doctors, and patients at various levels [4]. Key components of the imaging process, such as patient scheduling and protocol selection, must occur before image generation, diagnostic interpretation, and report generation can be performed [5][6][7].
PDCA management method ensures the effect and quality of management by formulating activity methods and steps strictly [8][9][10]. At present, lung cancer is one of the malignant tumors that endanger human life and health. Its morbidity and mortality are at the top of the list [11]. According to the statistical analysis of cancer epidemiology in 2013, the 5-year survival rate of lung cancer is only 15% [12]. e survival rate of lung cancer can be significantly improved by surgical resection in time.
erefore, early diagnosis of lung cancer can improve the survival rate of patients and reduce the rate of nodule thoracotomy with lung benign [13]. e PDCA management and the statistical methods [14,15] are always used to control the occurrence of the problems by analyzing the problems and the causes of the problems [16]. With the development of multislice spiral CT technology and the rapid development of scanning technology in lung cancer screening, the detection rate of pulmonary nodules has significantly increased. However, the focus of pulmonary nodule is usually small, and conventional scanning cannot clearly show the morphological features of the focus. Some phenomena increase the rate of misdiagnosis, such as volume effect after calcification of nodules and solid nodules presented as ground glass nodules. e CT target scan of pulmonary nodules can clearly show the signs of vacuole, lobulation, air bronchus, and margin [17,18]. e purpose of our study was to apply the advantages of PDCA cycle management to the quality control management of CT target scanning of pulmonary nodule, which improves the image quality significantly.

Materials.
e prospective study was approved by the ethical committee of Ninghai First Hospital. In this study, we implemented PDCA management method on January 1, 2019, and selected 60 patients' image of CT target scanning of pulmonary nodules per month from September 1st, 2018, to April 30th, 2019.
ere was no significant statistical difference between the selected data (P < 0.05), and the results were comparable.

Methods.
Before implementing the PDCA management method, the routine method is used to manage CT target scanning of pulmonary nodules; since January 2019, the PDCA circulation method is used to manage it and the PDCA project improvement and implementation team are established. All the staff members of the department participated in the team. e director of the department was appointed as the team leader and responsible for the implementation, training, and supervision of the members of the team. e group meeting is held every week.

Planning (P).
We established a PDCA project improvement implementation team with department director as the leader and organized all members of the department to brainstorm the reasons for the poor image quality of CT target scanning part of pulmonary nodules, the nonuniform standard of image postprocessing and reconstruction, and the nonstandard numerical measurement. e fishbone diagram of poor quality of CT target scan of pulmonary nodules is shown in Figure 1, and the detail plans are shown in Table 1.

Do (D).
e improvement measures for the noncompliance with the diagnostic specifications (the first reason shown in Table 1) are as follows: (1) e director of the department organizes all the staff members to study the "CT scan specification of pulmonary nodules" and "imaging diagnosis specification of pulmonary nodules" regularly.
(2) According to the standard, we hold a seminar on the improvement of CT target scanning image of pulmonary nodules and put forward the improving measures and that can be used to solve existing problems on CT target scanning of pulmonary nodules, as follows: (i) In order to improve the problem of nonstandard reconstruction image caused by the unreasonable FOV setting of thinning image, the scanning technician selects the upper and lower +3 cm nodules according to the upper and lower ranges of the specifications, and one lung field and half mediastinum are selected for thinning in the left and right ranges. e reconstructed image was not standard due to the unreasonable FOV setting of thinning image. (ii) e measures to strengthen the management of scanning plan to improve the problem caused by wrong position selection are as follows: on the day of appointment scanning, the registration personnel shall fill in the basic information of the patient and send it to the doctor of the diagnosis group to mark the location of the nodule; the scanning plan sheet shall be transferred to the CT operation platform for storage; on the day of scanning, the technician shall determine the location of the nodule scanning according to the location marked on the plan sheet and carry out accurate scanning. e lateral position shall be adopted for the CT target scanning of the pulmonary nodule according to the location of the nodule. According to the location of the nodule, the position can be adjusted to recline, supine, and prone so that the nodule is located at the center of the radiation field at the top of the chest. (iii) e following measures are taken to solve the problem of blur artifacts caused by poor breath holding: the simple and practical method is adopted so that the patients can carry out breathing training in an understanding way, and it can be demonstrated on the spot, establishing the corresponding dialect training mechanism for county hospital, the voice prompts of inspiratory breath holding operation added to the scanning console, and some certain time inspiratory live demonstration for elderly patients; respiratory training was conducted in the scanning interval of the last patient for improving scanning efficiency.
(iv) e unreasonable improvement measures for the measurement of nodule diameter surface are as follows: measure the maximum diameter and its vertical diameter at the maximum level of transverse section, and calculate the average diameter; if there is postprocessing, measure the maximum diameter and its vertical diameter at the second large section on MPR and calculate the average value. We measure them on fc52 with a thickness of 3 mm for effect comparison.  (v) In order to solve the problem of irregular measurement of CT value of nodule, the CT value was measured on fc03, superimposed with 1 mm slice thickness image, and the CT value of lung background was measured for comparison. (vi) In order to solve the problem of image distortion caused by MIP or MINP reconstruction, we unify the image and select the average menu for reconstruction.
e measures for testing the theoretical knowledge and CT scanning procedures of pulmonary nodules are as follows: (i) Using "Ding Ding" app to check theoretical knowledge. (ii) Detecting the scanning image quality after the improvement measures, and trace each nonstandard image to the responsible employee. (iii) Retraining and assessment of unqualified employees. e corresponding measures taken due to poor process (the second reason shown in Table 1) are as follows: improve the appointment process of CT target scanning of pulmonary nodule: (i) Improve the appointment process of CT target scanning of pulmonary nodule: if the routine CT is performed in our hospital, the CT target scanning of pulmonary nodule can be performed directly; if the routine CT is performed in the external hospital, the CT target scanning of pulmonary nodule can also be performed in our department with the CT film and report sheet; if only the chest plain film is performed, the CT target scanning of pulmonary nodule cannot be performed in our department, and the patient should be examined by routine CT scanning before deciding whether to have a CT target scanning. (ii) Attach the flow chart of CT target scanning (shown in Figure 2) to the box where the target scanning plan is stored, and the technician should process it according to the CT target scanning flow of pulmonary nodule strictly. (iii) Attach the flow chart of CT target image reconstruction of pulmonary nodules (shown in Figure 3) on the table of the image-reconstruction computer where the target scanning plan is stored, and the diagnoses should reconstruct it according to the reconstruction procedure.
For problem of the unskilled technician (the third reason shown in Table 1), the senior doctors will conduct one-toone guidance and training for the junior doctors, and the regular assessment will be conducted after the training.

Check (C).
When they viewed the CT images, the readers were asked to make a diagnosis, evaluate the quality of CT findings, and assign scores using a 100-point score as follows: (1) Each CT image was subjectively evaluated and graded using a 100-point score, and the detailed scoring items are as follows: (i) Scanning position selection (10 points (2) Diagnostic confidence: "90-100" indicated excellent, and "80-90" indicated full good.

Action (A).
e actions are as follows: (i) According to the norms of pulmonary nodule scanning and diagnosis, the technician scans the pulmonary nodule to narrow the scanning range and POV value, and the diagnostic physician measures the CT value of ground glass nodule during reconstruction. (ii) We analyze the unqualified target scanning image to find out the problems and improve continuously every month. (iii) Administrators need to gather the clinical needs and suggestions every quarter, and the team needs to rectify it and feedback in time. (iv) Holding training in theory and technology for employees every year.

Image Excellent
Rate. e image quality was evaluated by radiologists from the aspects of noise, artifact, contrast, and resolution. e image excellent rate is given by where m is the number of high-quality CT scanning image and n is the total number of CT scanning image.

Inspection Time.
In this study, we identified patients with at least one pulmonary nodule who came to our hospital. Two sets of images with 480 images were selected the final analysis. e one set images were selected from September 1st, 2018, to December 31th, 2018 (60 images per month), which were performed using routine CT scanning. e other set images were performed under CT target scanning from January 1st, 2019, to April 30th, 2019 (60 images per month). For each month, we evaluate the quality of CT findings and assign scores using the 100-point method, which is introduced in Section 2.2.3. e questionnaire survey was used to count the satisfaction of patients with our method. Inclusion criteria were as follows: operation process, service attitude, examination environment, health education, and inspection report and graded using a 20-point score according to a previous report. e total score is 100 points, and the score is directly proportional to the patient's satisfaction.

Statistical Analysis.
Data analysis was performed using the SPSS21.0 software package (SPSS Inc. Chicago, IL, United States). e diagnosis results, treatment recommendation, and diagnosis accuracy were determined using McNemar tests. e Wilcoxon signed-rank test was used to evaluate the image quality scores of the findings and confidence of readers. A P value of less than 0.05 was considered statistically significant.

Comparison of Image Excellent
Rate. As a result, 480 patients were included the final analysis, and the detail results of CT image quality are shown in Table 2 (all P < 0.05).

Comparison of Inspection Time.
Before the implementation of PDCA management, the CT target scan image score of pulmonary nodules is shown in Table 3. From September to December in 2018, the excellent rates of CT images were 60.0%, 76.6%, 83.3%, and 86.3%, respectively. e excellent rates of CT images with PDCA management have significantly higher score than without PDCA management. From January to April of 2019, the excellent rates of CT images were 90%, 95.0%, 93.3%, and 96.6%, respectively (shown in Table 4).

Comparison of Patient Satisfaction.
After the implementation of PDCA management, the patients' satisfaction with the examination was significantly higher than that without the implementation of PDCA management, and the P value of less than 0.05 was considered statistically significant; the results are shown in Table 5. Figures 4 and 5 show two representative cases. In cross-sectional images and corresponding MPR images, the edge of nodules and solid internal components were shown more clearly with PDCA management than that without PDCA management.

Discussion
e PDCA method originates from industry and Walter Shewhart and Edward Deming's articulation of iterative processes which eventually became known as the four stages of PDCA [2]. PDCA cycles offer a supporting mechanism for iterative development and scientific testing of improvements in medical diagnosis management [19]. In clinical examination, the image quality obtained by CT target scanning is often not high, thus affecting the diagnosis of patients [20][21][22]. However, the excessive and large region CT examination will increase the risk of high cumulative radiation doses. erefore, it is very important to manage the quality of CT target scan scientifically and effectively. Compared with the standard of technical and diagnostic, the quality of some images of CT target scanning of pulmonary nodules in our department is not high, the standards of image postprocessing and reconstruction are not unified, and the numerical measurement is not standardized.
In this study, PDCA management method was carried out in CT target scanning of pulmonary nodules in our department. In the planning stage (P), we analyzed the main reasons for the low excellent rate of pulmonary nodule image of CT target scanning in our department. e management plans are made to improve the quality of CT target scanning. e medical staff members were trained according to the operation and diagnosis criterion of CT target scanning of pulmonary nodule. In the implementation stage (D), the formulated measures were implemented strictly and all staff members carried out self-inspection actively. In the check     stage (C), the implementation of the measures shall be strictly supervised, and the corresponding operation results shall be spot checked to form the quality table of target scanning of pulmonary nodule. We also summarized and analyzed the existing deficiencies and recorded all rectification measures. In the action stage (A), we analyzed the unqualified target scanning images every month to find out problems and improve them continuously. e problems are found to be continuously improved and incorporated into the next cycle management. en, we put the new problems into the next cycle management and make a new plan to gradually improve and perfect the procedure. e results indicated that CT target scanning with PDCA management method can provide a higher image excellent rate compared to without PDCA management method. e application of scanning plan sheet can shorten the examination time and make the localization of scanning nodule more accurate. It can improve the efficiency and quality of the examination process to strengthen the breath holding training of patients according to the CT scan standard of pulmonary nodules. e measurement of the nodules of ground-glass and CT value of lung background can improve the quality of reconstruction image through the use of PDCA cycle to effectively control management of CT target scanning of pulmonary nodule, reduce the radiation dose of patients, optimize the patient's examination process, improve the patient's satisfaction, and achieve good results.

Data Availability
e simulation data used to support the findings of this study are available from the corresponding author upon request.

Ethical Approval
is article does not contain any studies with human participants or animals performed by any of the authors.

Disclosure
Dongquan Liu and Shaojun Zhu should be regarded as the co-first authors.

Conflicts of Interest
e authors declare that they have no conflicts of interest.

Authors' Contributions
Dongquan Liu and Shaojun Zhu contributed to the work equally.