Study On The Diagnostic Efficacy Of Diffusion-Weighted Magnetic Resonance Imaging In Malignant Pleural Diseases

Background and objective:Pleural disease is one of the most common diseases in respiratory system.Multiple causes can lead to pleural effusions or pleural thickening.The corresponding treatment options are different for the primary diseases,and treatment effect and prognosis also undergo divergence.Especially for patients with lung cancer,the evaluation of pleural metastasis has important reference value for the choice of treatment options and their clinical prognosis.Therefore,the benign and malignant identification of pleural disease is of great significance,and imaging examination plays an important role in the evaluation of pleural diseases.At present,chest CT is widely utilized in clinical practice and has become a routine imaging examination for pleural diseases.However,the CT sensitivity of different studies varies from 38%to 72%,which leads to the controversial diagnostic value of chest CT for pleural diseases.And for patients with pleural diseases which are difficult to diagnose,the radiation damage caused by repeated chest CT examination can not be ignored.Compared with CT,MRI has better soft-tissue contrast,higher intrinsic flow sensitivity and no ionizing radiation.The basic principle of diffusion weighted imaging magnetic resonance imaging（DW-MRI）is to reflect the internal microstructure changes of the tissue by detecting the diffusion motion of water molecules on the basis of morphology.As a new functional imaging technique,DW-MRI has shown great potential in the clinical application of multiple diseases.However,the current research on DW-MRI for malignant pleural diseases is relatively limited,and its diagnostic value still needs further exploration.The aim of this study was to evaluate the diagnostic efficacy of DW-MRI and two different assessment methods of chest CT in distinguishing benign and malignant pleural diseases.Further imaging analysis was also performed to evaluate the presence or absence of pleural metastasis in patients with lung cancer,in order to estimate the value of thoracic DW-MRI in accurate staging of lung cancer patients.Methods:According to inclusion and exclusion criteria,70 patients with pleural effusions or pleural thickening were enrolled.Within 2 weeks,thoracic DW-MRI,chest CT examination and thoracentesis or pleural biopsy were performed.Pleural effusions were examed for pathological cytology and pleural biopsy specimens for histopathological and immunohistochemical staining.The chest CT was assessed by two methods using the traditional visual signs evaluation（recorded as CT¹）and the systematic score evaluation（recorded as CT²）.The pathological results were used as the standard to compare the sensitivity,specificity and accuracy of DW-MRI and chest CT in the diagnosis of malignant pleural disease.Also 54 patients with lung cancer of them were evaluated whether they had pleural metastasis or not.Results:（1）The sensitivity,specificity and accuracy of chest CT using traditional visual signs（CT¹）and systematic scoring evaluation（CT²）for the diagnosis of malignant pleural diseases were 67.3%,72.2%,68.6%and 82.7%,61.1%,77.1%,respectively（P>0.05）.There was no significant difference in sensitivity and specificity between the two methods（P>0.05）.（2）The sensitivity,specificity and accuracy of thoracic DW-MRI in the diagnosis of malignant pleural diseases were 94.2%,72.2%and 88.6%,respectively.The sensitivity of thoracic DW-MRI was significantly higher than that of CT¹（P<0.01）.（3）There was no significant difference in the specificity of DW-MRI,CT¹ and CT²for diagnosing of pleural metastasis of lung cancer（P>0.05）.Sensitivity of DW-MRI,CT¹ and CT² was 93.9%,69.4%and 81.6%,and the accuracy was 87.0%,72.2%and75.9%,respectively.The sensitivity of DW-MRI was significantly different from that of CT¹（P<0.01）.In addition,the possibility of pleural metastasis in patients with lung cancer who had the potential to benefit from surgery(staged T_1-4N_0-1 or T_1-2N₂)was also assessed.The pathological coincidence rates of DW-MRI,CT¹ and CT² were 100.0%,73.7%and 84.2%,respectively.There was statistical difference between DW-MRI and CT¹（P<0.05）.Conclusion:Thoracic DW-MRI,which combined with anatomical and functional imaging,is superior to CT in the differential diagnosis of benign and malignant pleural diseases.Pleural lesions with high signal intensity on DWI combined with traditional imaging signs are more reliable and accurate in diagnosis of malignant pleural diseases.Especially in patients with lung cancer,DW-MRI can better identify the occurrence of pleural metastasis in order to perform more accurate staging and reduce unnecessary invasive examinations,which processes a promising prospect of its clinical application.