The Study On Diffusion-weighted MR Imaging In Solitary Pulmonary Nodules

Objective:To study the feasibility of diffusion-weighted imaging(DWI)features in the solitarypulmonary nodules,and choose the optimal scan method and b value.To evaluate the DWIperformance and apparent diffusion coefficient(ADC) of differential diagnostic value andlimits om the solitary pulmonary nodules.Materials and Methods:Seventy-six patients（40female，36man）with seventy-six lesions of The ShandongQianfoshan Hospital from September2011to May2012unwent unenhanced CT、MRI andDWI scanning，who is the diameter of the solitary pulmonary nodules，were enrolled in thisstudy。The average age of patients was59years（28-81years old）。In the76cases oflesions，there are63cases of malignan（30cases of squamous cell carcinoma，33cases ofadenocarcinoma），and13cases of benign nodules （5cases of tuberculosis ball，3casesof inflammatory pseudotumor，5cases of hamartoma）。All cases were confirmed bypathology (surgery, biopsy, bronchoscopy)。Scanning with different different b values (0、500、700、900s/mm2) gets DWI and ADC images，measuring signal intensities of DWI andADC values of the lesions under different b values。Then doing the following analysis：（1）ADC values were measured nodules under the b value, then analysising the differencebetween the ADC compare different b values of benign nodules and malignant nodules。（2）Applying ROC curves under different b values analysis the different diagnositperformances of ADC values between malignant pulmonary lesions and benign lesions，then selecting theoptimal b value and confirm the diagnostic threshold。（3）Finally， quantitatively analyse the ADC values of the solitary pulmonary nodules with the optimalbvalue and compare the differences of ADC values between lung benign lesions andmalignancy and some different histological types of lung cancer。Results：ADC values of the solitary pulmonary nodules decreased with the increase of bvalues， the ADC value differences under different b values between groups werestatistically（p＜0.05）。When b value=700s/mm2，ADC values has the higest performncein the diagnostis，ROC area under the curve（Az）is the largest，The sensitivity, specificity,positive predictive value and negative predictive values were92.86%,76.92%,93.75%and66.67%。When the optimal b value is700mm2/s，ADC values of malignancy were（1.32±0.27）×10-3mm2/s，ADC values of malignancy were（2.22±0.34）×10-3mm2/s，there was statistical significance between ADC values for malignant pulmonary tumors andbenign lesions（p＜0.05），ADC values of malignant lesions were significantly lower thanthose benign lesions。ADC values of squamous cell carcinoma were（1.286±0.623）×10-3mm2/s，ADC values of adenocarcinoma were（1.452±0.521）×10-3mm2/s，there wasstatistical significance between ADC values for quamous cell carcinoma andadenocarcinoma （p＜0.05）。Conclusion：DWI examination is feasible for assessing malignant pulmonary lesions and benignlesions，and realizes quantitative analysis of ADC values of the solitary pulmonarynodules，and it may be a new ideal method in diagnosis the solitary pulmonary nodules。Therefore DWI examination is a beneficial complement for conventional CT and MRIexamination。...