Evaluation Of Deep Bone Suppression Imaging(deepBSI) For Lung Nodule Detection:A Comparative Study

[Background and Objective]In recent years,lung cancer is the world’s highest prevalence and mortality of malignant tumors.In China,the incidence and mortality of lung cancer also showed a significant increase.In 2015,the incidence and mortality of lung cancer ranked the first among malignant tumors.Early screening and diagnosis is the key to reducing mortality.Clinical imaging examination is the most common method of lung cancer screening and diagnosis.At present,imaging methods include general chest X-ray,computed tomography(CT)and so on.Chest CT is the most commonly used method for the qualitative,staging,and follow-up of lung cancer.However,there is a large dose of radiation,could not be used as a first methods.Chest X-ray is cheap,simple and easy to use,low radiation dose is the most basic examination of the chest,the current use of more digital radiography(Digital radiograph,DR).Early lung cancer often presents as a solitarynodule in the chest radiograph.However,there is an overlap of anatomical structures on the chest radiograph and the lung lesions are easily obscured and the detection sensitivity is low.A number of studies report that the missed diagnosis of pulmonary nodules is mainly caused by Bone structure occlusion.With the development of imaging technology,some imaging-based technologies have been developed based on DR,including Dual energy substxaction(DES)and deep bone suppression imaging(deepBSI)And Digital Tomosynthesis(DTS).The aim of this study was to evaluate the clinical value of the four methods in detecting pulmonary nodules by analyzing the diagnostic capabilities of four methods:DR,deepBSI,DES and DTS,The research into two parts.The first part studied the detection rate of pulmonary nodules in the four methods.The second part evaluated the diagnostic efficiency of four kinds of examination methods in solitary pulmonary nodules by ROC curve analysis.[Materials and Methods]1.Clinical informationCollection of our hospital 2016.12～2017.09 line chest X-ray examination of 288 patients,aged 18 to 70 years.All the patients underwent X-ray,DES and DTS examinations.CT was taken as the gold standard to diagnose pulmonary nodules in 155 cases(single nodules in 126 cases,multiple in 29 cases)and blank control group in 133 cases.A total of 305 nodules was detected.Three radiologists and three residents a total of six physicians participated in the experiment.129 cases of single nodule classification:According to the distribution of nodules is divided into three groups:upper,middle and lower lung field;according to nodules and ribs overlap area divided into two groups:<50%,>50%;by nodule diameter divided into three groups:<6mm,6～10mm,>10mm.2.Equipment and methodsGE XR650 X-ray system is used for both DR,DES and DTS.BSI imaging uses deep convolutional network bone imaging(deepBSI)technology model.3.lung field divisionThe lung field on each side to the second anterior inferior margin and the fourth anterior inferior border as the border into the upper,middle and lower lung field.4.Rating rulesScoring 0～100 points system,0 points certainly no nodules,100 points certainly have nodules.0～20 points:approaching the lung no nodules;21～40 points:the lung may not exist nodules;41～60 points:the lung may exist nodules;61～80 points:the height of the lung may exist nodules;81～100:approaching certainly nodules.5.Image evaluationDisplayer:double screens liquid crystal display,EIZO G22 type.PACS:START-PACS invented independently by Southem Medical University.6 physicians independent double-blind reading:Take DR images →deepBSI images→DEIS images →DTS image reading sequence.Observations:includes two parts,the first part:DR,deepBSI,DES,DTS four images show the number of nodules.The second part:the confidence score of pulmonary nodules in four images of DR,deepBSI,DES,DTS.Before the formal experiment through pre-experiment so that each physician familiar with the judgment criteria,observation and operation of the process.6.Statistics analysisIn the first part,the number of pulmonary nodules was shown by CT as the relative gold standard.According to the different seniority of physicians,the physicians were divided into two groups:low and high senior,,two groups were observed between the observation results,P<0.05 considered statistically significant,comparing the DR,deepBSI,DES,DTS four methods of lung nodule detection rate.In the second part,according to different doctors ’seniority,different nodules were distributed in different positions.According to the nodules’ size,according to different nodule and rib overlap area,the observation results between groups and groups were Z Test,P<0.05 considered statistically significant,the four methods of diagnosis of pulmonary nodules diagnostic efficacy.[Results]First part:Different years physicians four check the number of pulmonary nodules detectedDR,deepBSI,DES,DTS four examination methods,the number of 148,191,192,229 were detected by three residents;195,234,231,277by three radiologists.2.Chest DR,deepBSI,DES,DTS four methods of detection of pulmonary nodule detection rate comparisonSix physicians,the four methods of detection of lung nodules were not all the same,radiologists and residents research results above.The detection rates of six physicians,deepBSI,DES and DTS nodules were all higher than those of DR,the differences were statistically significant.3.When physicians are different,the nodules detection rate comparisonThe overall detection rates of DR,deepBSI,DES and DTS in residents were about 48.52%,62.62%,62.95%and 75.08%respectively.The overall detection rates of radiologists were 63.93%,76.72%and 75.74%,90.81%respectively.The detection rate of nodules under the four examinations by radiologists and was higher than that of residents,with statistical significance.Comparing to DR,the detection rate of deepBSI,DES,DTS by residents increased more than radiologists.The second part1.DR,deepBSI,DES,DTS four methods of detection of SPN under the area under the ROC curve were about 0.760,0.882,0.884,0.946.2.Chest DR,deepBSI,DES,DTS four methods of diagnosis of SPN under the ROC curve area analysisThe area under the ROC curves of six physicians,deepBSI,DES and DTS in diagnosing SPN were all higher than those in DR and DTS higher than those in deepBSI and DES.The area under the ROC curve of deepBSI and DES diagnostic nodules was similar,with no significant difference.3.When the physician different seniority,four kinds of examination method to diagnose the area under the ROC curve analysis of SPN①Under the four methods of DR,deepBSI,DES and DTS,the area under the ROC curve of diagnosis nodules of radiologists was higher than that of residents.② When the nodules were located in the upper lung field,the areas under the ROC curve of the four diagnostic methods were higher than those of the radiology residents,but no significant difference.③ When the nodules were located in the mid-lung field,the difference between radiologists and residents was statistically significant.④When the nodules were located in the lower lung field,the area under the ROC curve of the diagnostic methods of the four senior high-grade examinations was higher than that of the residents,and there was a significant difference.There was no significant difference between DES and DTS.⑤the deepBSI,DES,DTS and DR AUC value for three residents greater than radiologists.4.When the nodules are located in different lung field,the area under the ROC curve of four methods of diagnosis of solitary pulmonary nodules① When the nodules were located in the upper lung field,the area under the ROC curves of the deep BSI,DES and DTS in the diagnosis of SPN were all higher than those in the DR and DTS,all of them were significantly different.Radiologists research results above.For residents,DTS was higher than deepBSI and DES,but neither was statistically significant.② When the nodules were located in the mid-lung field,the area under the ROC curves of deep BSI,DES and DTS was significantly higher than that of DR and DTS in deep BSI and DES.Radiologists and residents research results above.③ When the nodules were located in the lower lung field,the areas under the ROC curves of deep lungs and pediatric patients with deep BSI,DES and DTS were significantly higher than that of DR and DTS.Residents research results above.The area under the ROC curve of isolated pulmonary nodules diagnosed by deep BSI and DTS were 0.875 and 0.929 respectively,with no significant difference.5.When nodules and ribs overlap area,four kinds of examination method to diagnose the area under the ROC curve analysis of SPN① The area under the ROC curves of deep BSI,DES,DTS in SPN diagnosed by 6 physicians was higher than that of DR and DTS higher than that of deep BSI and DES when the overlapping area of ribs was<50%or>50%.Radiologists and residents research results above.② When the overlapping area of ribs was>50%,the differences of AUC between deepBSI,DES,DTS and DR of 6 physicians were greater than 50%of the overlap area of ribs.6.When the nodules of different sizes,four kinds of examination methods to diagnose SPN under the ROC curve area analysis① When the nodules were less than 6mm andwas 6～10mm,the areas under the ROC curve of the deepBSI,DES,DTS diagnostic nodules were all higher than those of the DR and DTS in the six physicians.Radiologists and residents research results above.②When the nodules were larger than 10mm,the area under the ROC curve of the deepBSI,DES and DTS diagnostic nodules were all higher than those of the DR and the areas under the ROC curves of the DTS diagnostic nodules were higher than the deepBSI and DES.Residents research results above.For radiologists,the areas under the ROC curves of deepBSI,DES,and DTS diagnostic nodules were all significantly higher than those of DR.DTS were higher than deepBSI,DES,were not statistically significant.③ When the diameter of tubercle was less than 6mm and>6mm,the difference of AUC between deep BSI,DES,DTS and DR of the former 6 physicians was large.The difference of AUC between DTS and deepBSI and DES was large.Radiologists and residents research results above.The area under the ROC curves of deepBSI and DES diagnosis nodules were all similar in different classification for different years physicians,there was no significant difference.[Conclusion]1.In general,the deepBSI DES,DTS nodule detection rate and diagnostic efficacy are better than ordinary DR,DTS is better than deepBSI,DES.especially for residents.the detection rate and diagnostic efficiency of deepBSI,DES,and DTS methods are superior to those of DR.DTS is better than deepBSI and DES.deepBSI and DES always similar.When the nodules are located in the upper-middle lung field,the greater the overlap area between nodules and ribs and the smaller of the nodule,the deepBSI,DES,and DTS have more obvious advantages.In addition,the three methods are used to help the residents.2.There is no comparative study between BSI and DTS.Compared with deepBSI,DTS is more helpful to improve the detection rate and diagnostic efficiency of pulmonary nodules,especially in the middle lung field and small nodules.When the nodule is located in the lower lung field,respiratory motion artifacts are easily generated on the DTS image,and there is no obvious advantage.Compared with DTS and DTS,DTS is more helpful,especially for nodules located in the middle lung field and small nodules.When the nodules are located in the upper and lower lung fields,there is no obvious advantage in DTS,which is related to the DTS image volume limitation and the lower lung field respiratory motion artifacts.3.The DR examination is the most common method for chest examination.However,the lesions are often misdiagnosed and missed in the DR image.When there are suspicious lesions on DR films or the differential diagnosis is difficult,the three methods deepBSI,DES and DTS can be used as further examination methods.DES and DTS are mainly applicable to the review of patients with suspicious lesions in DR images,difficult diagnosis of some lesions and patients with previous tumor history.Screening for early stage lung cancer in high-risk groups will also help,but whether it can reduce lung cancer mortality needs further study.Compared to DR,DES and DTS need to increase the radiation dose and need to install additional machinery and equipment.The operation time is long and the patient needs to control the breathing.It is not applicable to patients with severe diseases in the lung,obese people and patients with poor respiratory control.Can it be widely used?Routine chest examination in the general population needs further clinical validation.4.The deep bone suppression imaging(deepBSI)technology does not require additional radiation dose and installation of equipment,as a computer post-processing software,can automatically decompose any chest X-ray to obtain a simple soft tissue and bone tissue image,suitable for any disease that requires chest DR examination has a promising clinical application.