| Objective By collecting the CT value and MRI T1 value of lung cancer before operation,the extracellular volume fraction(ECV)and its difference of different pathological types of lung cancer confirmed by postoperative or biopsy pathology were calculated and analyzed.To compare the diagnostic performance of two ECV parameters based on CT value and T1 value for pathological classification of lung cancer,and to explore their clinical application value.Methods A total of 62 patients with lung cancer who were hospitalized in Shandong Provincial Hospital Affiliated to Shandong University from September 2020 to March 2021 and were eligible for inclusion were prospectively recruited.Including 33 cases of adenocarcinoma,16 cases of squamous cell carcinoma,13 cases of small cell lung cancer.All cases received CT and MRI plain and enhanced scans before treatment.(1)CT scan:The scanning equipment is Germany Siemens Force CT scanner.The body position is supine with feet advanced.The scanning range is from the apex of the lung to the lower border of the lung.A thin-layer plain scan was performed first.Then,iohexol was injected through the right anterior cubital vein.And select the thoracic aorta as the trigger level.When the CT value of the thoracic aorta reached the threshold(100Hu),the arterial phase was scanned with a delay of 6 seconds,and the venous phase was scanned with a delay of 25 seconds.(2)MRI scan:The scanning equipment is German Siemens Prisma 3T MR scan and 1 8channel phased array body surface coil.The body position is supine with head advanced.The scanning range is from the apex of the lung to the lower border of the lung.Prior routine sequence scans(including T1-VIBE-COR,T2-HASTE-COR,T2-BLADE-TRA,T1-VIBETRA and DWI).Then,the B1 field corrected variable flip angle VIBE sequence was used to acquire T1 mapping images.Gd-DTPA was used for dynamic enhanced scanning.The B1 map was pre-scanned again,and then the MRI T1 mapping scan was performed.The scan parameters and positions are the same as those of the plain scan T1 mapping.(3)Data acquisition:The images were processed by two physicians with more than five years of clinical experience using Siemens syngo.via workstation.The ROI was delineated on the mediastinal window of CT and the pseudo-color image generated by T1 mapping,avoiding calcification,blood vessels and artifact areas seen by the naked eye.The CT value and T1 value of the lesion and blood pool before and after enhancement were recorded,and the patient’s hematocrit was collected.The extracellular volume fraction based on CT value(ECV-CT)and the extracellular volume fraction based on MRI T1 value(ECV-T1)were calculated according to the formula.(4)Statistical processing:IBM SPSS software(Version 25;Armonk,NY,USA)was used for statistical analysis of data.P<0.05 was regarded as a statistically significant difference.Results(1)CT image results:ECV-CT of small cell lung cancer and non-small cell lung cancer were(11.69±3.65)%and(18.09±6.32)%,respectively.NSCLC was larger than SCLC,and the difference was statistically significant(P<0.01).In NSCLC,adenocarcinoma and squamous cell carcinoma ECV-CT were(17.17±4.92)%and(19.98±8.38)%,respectively.Squamous cell carcinoma tended to be larger than adenocarcinoma,but the difference was not statistically significant(P>0.05).(2)MRI results:The mean values of ECV-T1 in SCLC and NSCLC were(13.79±5.93)%and(27.17±6.59)%,respectively.NSCLC was larger than SCLC,and the difference was statistically significant(P<0.01).In NSCLC,the mean values of ECV-T1 in adenocarcinoma and squamous cell carcinoma were(24.21±4.92)%and(33.28±5.32)%,respectively.Squamous cell carcinoma was larger than adenocarcinoma,and the difference was statistically significant(P<0.01).(3)Comparison of CT and MRI results:First,small cell lung cancer is compared with nonsmall cell lung cancer.The area under the curve of ECV-CT was 0.827(95%confidence interval was 0.707-0.947),the best cut-off value was 13.93%,and the sensitivity,specificity,and accuracy were 73.5%,84.6%,and 75.8%,respectively.The area under the curve of ECVT1 was 0.936(95%confidence interval was 0.842-1.000),the optimal cutoff value was 18.97%,and the sensitivity,specificity,and accuracy were 89.8%,92.3%,and 90.3%,respectively.The sensitivity,specificity and accuracy of ECV-T1 are higher than ECV-CT.Then,squamous cell carcinoma was compared with adenocarcinoma.The ECV-CT of squamous cell carcinoma tended to be greater than that of adenocarcinoma,but the difference was not statistically significant(P>0.05).The ECV-T1 of squamous cell carcinoma was greater than that of adenocarcinoma,and the difference was statistically significant.The area under the curve was 0.890(95%confidence interval was 0.789-0.991),the optimal cutoff value was 29.11%,and the sensitivity,specificity,and accuracy were 84.8%,81.2%,and 83.7%.Conclusion The extracellular volume fraction can reflect the tissue structure of lung cancer,and can accurately and non-invasively evaluate the pathological type of lung cancer.ECV-CT and ECV-T1 can quantitatively differentiate small cell lung cancer from non-small cell lung cancer.ECV-T1 has higher sensitivity,specificity and accuracy.And ECV-T1 can further distinguish squamous cell carcinoma and adenocarcinoma,with higher diagnostic performance.It has important clinical value and significance for the preoperative imaging qualitative diagnosis of lung cancer and the prediction of pathological classification. |
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