Analysis Of Misdiagnosis Causes Of Pulmonary Nodules In Conventional DR Chest Film

ObjectiveTo investigate misdiagnosis causes of pulmonary nodules in the PA & LAT chest film of digital radiography(DR) by compared with multi-slice spiral CT.MethodsA retrospective analysis was performed to 136 patients(male 86,female 50,age range from 19 to 79,age average 49.0) with pulmonary nodules on the 64-slice computed tomography(MSCT),and all these patients underwent the PA & LAT chest film of DR within a week before or after the CT examination. 227 nodules were detected by the PA & LAT chest film of digital radiography while 296 nodules were detected by CT.Detection rates of pulmonary nodules by 64-slice CT and the PA & LAT chest film of DR was compared to analyze the difference causes.Siemens Sensation Cardiac 64-slice CT was used,and patients were told to have a deep breath before volume scanning from apex of lung to the level of costophrenic angle.The acquired data was transferred to Wizard Workstation and multiple planner reconstruction(MPR) was processed.KODAK-DR3000 was used in digital radiography,and the chest film was gotten from standard post-anterior position.The acquired data was transferred to KODAK Workstation as post-procession.All the data was analyzed by 2 radiologists independently.When consistency was obtained among the independent results,the diagnosis of misdiagnosis pulmonary nodules could be confirmed.SPSS12.0 software was used,and the size and detection rate was compared by x~2test.The difference was believed significant while P＜0.05.ResultsAmong 296 nodules detected on MDCT,227 were found on the PA & LAT chest film of DR,and the detection rate was 76.69%.In MDCT,20 nodules were found at apex pulmonis,10 at ilum of lung,14 in the posterior area of heart,21 by the sides of the backbone,13 at disphragmatic muscle, 45 at overlap compass of the cervical ribs,173 at the common lung field.69 nodules were misdetected on the conventional post-anterior DR chest film,of which 38 were at the in the lung crypticity compass(9 at apex pulmonis,2 at ilum of lung,4 in the posterior area of heart,6 by the sides of the backbone,4 at disphragmatic muscle,13 at overlap compass of the cervical ribs),and the other 31 were at the common lung field.4 of the 69 nodules displayed as frosted glass on MSCT,which could be found only in lung window,with the CT value below -600HU.MSCT detected 109 nodules whose diameter was no more than 10mm,while only 64 were detected by conventional DR post-anterior chest films,and the detection rate of DR was 58.72%. MSCT detected 187 nodules whose diameter was more than 10mm,while 163 cases were detected by the PA & LAT chest film of DR,and the detection rate of DR was 76.69%.Therefore,there was a significant difference between the diameter of the misdiagnosed pulmonary nodules and the detection rate on the PA & LAT chest film of DR(p＜0.05).ConclusionDetection rate of pulmonary nodules by MSCT was significantly higher than that by DR.The pulmonary nodules which were small,low density and at the compass of the lung could be easily misdiagnosed on the PA & LAT chest film of DR.