| Background and purpose Esophageal carcinoma is the eighth most common cancer worldwide.However,the overall prognosis of esophageal carcinoma remains poor due to the late stage and the poor preoperative stage at diagnosis.Computed tomography(CT)is widely employed to identify the relationships of surrounding organs and to assess distant metastasis of oesophageal carcinoma,but it does not reveal the invasion of the specific layer of the oesophageal wall due to poor soft-tissue contrast.Endoscopic ultrasonography(EUS)can be used to depict the mucosal and submucosal invasion but entails the limitation in the evaluation of muscularis propria and adventition.Magnetic resonance imaging(MRI)has been employed to evaluate esophageal wall invasion by esophageal carcinoma,and its potential as an alternative imaging modality to CT and EUS has been demonstrated.The purpose of this study is to prospectively determine the feasibility of 3.0 T MR imaging for evaluating the esophageal wall invasion by oesophageal carcinoma.Part 1: Esophageal carcinoma: comparsion of ex vivo high-resolution 3.0 T MR imaging with histopathological findingsObjective To prospectively determine the feasibility of 3.0 T MR imaging for evaluating the esophageal layers of the normal esophageal wall ex vivo and to subsequently assess the depth of oesophageal wall invasion by esophageal carcinoma.Materials and methods All the 95 esophageal carcinoma proven by gastroscopy biopsy were imaged by using a 3.0-T MR system.The MR images were interpreted by two experienced radiologists independently,who were blinded to the results of the histopathological examinations.When the two radiologists could not fully agree on the findings,a consensus was achieved by discussion.The stage at MR was compared with that at the histopathological findings.The corresponding MR images and histopathological slices were matched.The Kappa test was used to evaluate the MR findings and the histopathological results;and the sensitivity?specificity were used to assess the diagnostic efficacy.Results High-resolution MRI scan can clearly show the normal esophageal wall as consisted of eight layers which were consistent with histological anatomy.86(90.5%)of 95 cases,the MR stage were highly consistent with histopathological findings(Kappa=0.870).The sensitivity,specificity and accuracy of high-resolution MR imaging for T1 a staging were 76.9%?97.6% and 94.7%;for T1 b were 80.6%?95.3% and 90.5%,and T2 were 100%?94.2% and 95.8%;for T3 and T4 were100%?100% and 100%,respectively.Conclusion High-Resolution MRI can provide clear delineation of the esophageal wall layers in vitro with good diagnostic sensitivity,specificity and accuracy for assessing esophageal carcinoma invasion.Part 2: Esophageal carcinoma: ex vivo evaluation by high-resolution T2-mapping MRI compared with histopathological findings at 3.0TObjective To prospectively determine the feasibility of T2-mapping MR imaging to quantitatively describe the signal characteristics of the normal esophageal wall and assess the depth of esophageal wall invasion by carcinoma at 3.0 T.Materials and methods Fifty-two patient specimens,each having foci of carcinoma,were studied using 3.0T MR.Freehand regions of interest were placed to measure the T2 value of the normal esophageal layers and were comparedwith the regions of carcinoma.Three independent readers reviewed the MR images to evaluate the depth of carcinoma invasion;when the three radiologists could not fully agree with each other,the final stage was determined by consensus.The Games-Howell test was used to compare the difference between the normal esophageal layers and carcinoma.Spearman correlation coefficient analysis was used to compare the stage at MRI with that at histopathological analysis.The interobserver agreement was compared with Kappa test.The sensitivity,specificity,and accuracy for detecting carcinoma invasion were calculated.Results The T2 values between the carcinoma and normal esophageal layers were different(all P < 0.01),except for the inner circular muscle(P=0.790).The T2 value of each layer of the normal esophageal wall was also different from that of the adjacent layer(all P < 0.01).In 47 of 52 lesions,the depth of the esophageal wall invasion determined by MR was consistent with the histopathological stage(r=0.968,P < 0.001).The sensitivity,specificity,and accuracy were 75%,95.5%,and 92.3%,respectively,for invasion into the mucosa;80%,94.6%,and 90.4%,respectively,for invasion into submucosa;100%,97.4%,and 98.1%,respectively,for invasion into muscularis propria;and 100%,100%,and 100%,respectively,for invasion into the adventitia.Conclusion T2-mapping MR images obtained using a 3.0T MR scanner can be used to depict the eight histopathological layers of the esophageal wall clearly and provide excellent diagnostic accuracy for assessing esophageal carcinoma invasion.Part 3: Esophageal carcinoma: comparsion of in vivo high-resolution 3.0 T MR imaging with histopathological findingsObjective To prospectively determine the feasibility of High-resolution in vivo MR imaging in the evaluation of esophageal carcinoma invasion at 3.0 T.Materials and methods One hundred and thirty-five patients with esophageal carcinoma,proven by the gastroscopic biopsy,were consecutively included and studied using 3.0-T MR.Three independent radiologists reviewed the MR images to evaluate the depth of carcinoma invasion,when the three radiologists cannot fully agree on each other,the final stage were determined by consensus.The thickness of the tumors was also measured by the three radiologists.A pathologist identified the depth of carcinoma invasion of staging and measured the thickness of the tumor on the largest traverse diameter histopathological slice.The Kappa test was used to compare the stage of MR imaging with that at the histopathological analysis as well as the interobserver agreement.Bland-Altman scatterplots was used to compare the thickness of tumor measured on the MR images by three radiologists with that at the histopathological measurement and the interobserver agreement.Results 109(80.7%)cases of MR staging were highly consistent with the histopathological stage(Kappa=0.753).The sensitivity,specificity and accuracy were for T1 a were 57.1%? 98.3%?94.1%,respectively;for T1 b were 73.9%?94.6%?91.1%,respectively;for T2 were 76.9%?93.6%?90.4%,respectively;for T3 were 78.4%? 95.9%?91.1%,respectively;for T4 a were100%?95%?96.3,respectively.Bland-Altman scatterplots demonstrated that the discrepancy of the mean thickness between the three radiologists and the histopathological analysis were 2.0 mm?2.6 mm and 2.1 mm,the mean thickness for the interobserver were 0.6 mm?0.1 mm and 0.4 mm,which demonstrated a good consistency.Conclusion High-resolution MR images obtained using a 3.0T MR scanner can be used to provide excellent diagnostic accuracy for assessing in vivo esophageal carcinoma invasion. |
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