Detection Of Pulmonary Nodules: Optimization Of Sequence And The Diagnosis Of Invasive Lung Adenocarcinoma In MR

Part ? Detection of pulmonary nodules in MR:optimization of sequenceObjective: To study on the selection and optimization of sequence of 3-T magnetic resonance for detection of pulmonary nodules.Methods: Patients with ?6mm and ?20mm pulmonary nodules were collected prospective.All patients undergo 3-T MR scanning within 24 hours after CT scanning.The MR Sequences included T1-VIBE,T1-Star-VIBE,T2-TSE,HASTE.Adding 240 ms inverse recovery time to HASTE and T2-TSE repeat scanning.Two radiologists analysed images independently.The total detection rate,solid nodules' detection rate,ground-glass nodule' detection rate,CNR value and maximum diameter were calculated or measured.Gold standard is CT.The total detection rate of nodules,the detection rate of solid nodules or ground glass nodules,the CNR and the maximum diameter were compared.All statistical analyses were performed using SPSS 21.0.The measurement data were analyzed by using Wilcoxon test,count data were compared using chi square test.P<0.05 was considered statistically significant differences.Kappa test was used to evaluate two readers agreement.Result: 136 participants(74 men,59.8±10.1 year-old;62 women,56.7±14.3 year-old)with 145 nodules were examined from December 2014 to December 2016.The maximum diameter was 15.2±6.1mm.Among them,85 cases were solid nodules,maximum diameter was 14.7±6.3mm;60 cases were GGN,maximum diameter was 14.2±5.2mm.The total detection rate was 84.1%.The solid nodules' detection rate was 85.9%(73/85).The detection rates of solid nodule in each sequence were T1-VIBE(60%),STAR-VIBE(72.9%),HASTE(81.1%),HASTE-IR(82.4%),T2-TSE(76.5%),T2-TSE-IR(83.5%)respectly.The ground-glass nodule' detection rate was 81.6%%(49/60).The detection rates of GGN in each sequence were T1-VIBE(11.7%),STAR-VIBE(15.0%),HASTE(75.0%),HASTE-IR(78.3%),T2-TSE(66.7%),T2-TSE-IR(81.7%)respectly.There was no significant difference in the total detection rate of solid nodules and ground-glass nodules.The CNR values of each sequence were T1-VIBE(33.7±12.1),STAR-VIBE(95.1±33.2),HASTE(61.0±15.5),HASTE-IR(70.6±21.1),T2-TSE(47.3±12.2),T2-TSE-IR(71.9±22.1)respectly.There was statistical difference among each CNR values.The maximum diameter of the nodules in MRI was smaller than that of the CT images,and there was statistical difference.The Kappa value was 0.782(P<0.001)of the two readers.Conclusion: 3-T Magnetic resonance imaging has great potential in the detection of pulmonary nodules.HASTE-IR sequence and T2-TSE-IR sequence can be used for detection of ?6mm pulmonary nodules,and MRI can be used for the detection of ground-glass nodules.Part? The diagnosis of Invasive lung adenocarcinoma in MRIObjective: Discuss the value of magnetic resonance imaging(MRI)in the differential diagnosis of invasive pulmonary adenocarcinoma(IPA)appearing as ground-glass nodules.Methods:Retrospective analysis was performed on CT and MRI findings in patients with pulmonary ground-glass nodules in the Department of CT magnetic resonance imaging of the fourth hospital of Hebei Medical University from December 2014 to December 2016.All patients were surgically resected and pathologically proved to be precancerous lesions or clinical stage as stage ? lung adenocarcinoma.The MR Sequences included DWI,T1-Star-VIBE,T2-TSE,HASTE.Adding 240 ms inverse recovery time to HASTE and T2-TSE repeat scanning.The image features of the lesions were analyzed by two readers(one had more than 10 years of work experience and another had less than 5 years of work experience)who did not knowing the pathological results.Maximum diameter,T2 signal intensity and ADC value were measured.According to the pathology,the lesions were divided into two groups.One included preinvasive lesion(AAHs and AISs)and MIAs,another included IPAs.Compare this 3 indicators between two groups.All statistical analyses were performed using SPSS 21.0.The measurement data were analyzed by using two independent samples t test if satisfy the normal distribution,otherwise by Mann-Whitney U test.Count data were compared using chi square test.Receiver operating characteristic(ROC)curve analysis were performed to evaluate diagnostic test.P<0.05 was considered statistically significant differences.Results: A total of 34 participants(14 men,57.1±14.7 year-old;20 women,54.9±10.1year-old)with 34 nodules from December 2014 to December 2016 were enrolled in the study.There were 15 cases in group A,including 4 AAH,2 AIS and 9 MIA.There were 19 cases in group B.There was no significant differences in the age of patient and gender between 2 groups.The maximum diameter of lesions in group A was significantly less than that in group B(9.9±2.6mm vs 13.1±2.7mm,t=-3.405,P=0.002).The T2 signal intensity of lesions in group A was significantly lower than that in group B(93.0±8.3 vs 113.6±22.9,t=-3.6,P=0.001).The ADC value in group A was also significantly lower than that in group B(1.0±0.2*10-3 mm2/s vs 1.3±0.3*10-3 mm2/s,t=-2.697,P=0.011).The best index to distinguish 2 groups is the maximum diameter of lesions The optimal cut-off value for maximum diameter was 11.5mm(sensitivity,73.7%;specificity,73.3%).The AUC for maximum diameter was 0.791(95% confidence interval: 00.640,0.942).Conclusion: The maximum diameter of the nodule,T2 signal intensity and ADC value are helpful for the differential diagnosis of invasive lung adenocarcinoma.The best indicator for the differentiation invasive lung adenocarcinoma from the preinvasive lesions(including MIA)is the maximum diameter of the nodule.