| Part Ⅰ Value of Spectrum CT with isotonic mannitol gastrointestinal hypotonic radiography in the preoperative staging of rectal carcinomaObjective To evaluate the clinical value of spectral imaging combined with oral isotonic mannitol gastrointestinal hypotonic radiography in the diagnosis of preoperative staging of rectal carcinoma. Materials and Methods 90 patients with rectal cancer confirmed by surgery and pathology in our hospital were included in this study, all people were encouraged to drink up 2.5% isotonic mannitol and low distension,then received CT scan in the gemstone spectral imaging mode, after scanning the optimal contrast-to-noise ratio imaging were got by the spectrum analysis software, then evaluate the T-stage and compared with the pathological T-stage; Respectively using the traditional method and the spectral curve method to evaluate N-stage and compared with pathological N-stage. Results ①90 patients were able to successfully complete the examination, the rectal filling and lesions showed were satisfactory, and no obvious complications happened. ②The overall diagnostic accuracy of T-stage by the monochromatic images was 83.3%(75/90), which had a fair correlation with pathological results and the kappa value was 0.735 (P<0.001),among them, the T1～2, T3 and T4 diagnostic accuracy were 91.1%,83.3% and 92.2% respectively; the diagnostic sensitivity were 90.6%,82.5% and 72.2% respectively; the diagnostic specificity were 91.4%,84% and 91.4% respectively; the diagnostic positive predictive value were 85.3%,80.5% and 86.7% respectively; the diagnostic negative predictive value were 91.4%,85.7% and 93.3% respectively; the diagnostic positive likelihood ratio were 10.53,5.16,25.79 respectively; the diagnostic negative likelihood ratio were 0.10,0.21,0.29 respectively; ③The accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio of N-stage by the traditional method were 81.1%,82.2%,80%,80.4%,81.8%, 4.11,0.22 respectively, which had a general correlation with pathological results and the kappa value was 0.622 (P＜0.001); The accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio of N-stage by the Spectral curve method were 92.1%,86.4%,97.8%,97.4%, 88.2%,39.27,0.14 respectively, which had a fair correlation with pathological results and the kappa value was 0.844 (P＜0.001).Spectral curve method had higher Youden’s index for N-stage than traditional method (0.84 vs 0.62). Conclusion Oral isotonic mannitol gastrointestinal hypotonic radiography can provide a good rectal background, and it is a safe, convenient and efficient method for rectal examination, Combination with spectrum imaging, it can highlight the detail of lesions and judge the lesion homology to some extent, which might optimize preoperative T, N staging of rectal carcinoma.Part Ⅱ Value of Spectral CT imaging in quantitative evaluation on histodifferentiation of rectal adenocarcinoma in preoperativeObjective To discuss the value of the spectrum CT parameters in the preoperative evaluation on histodifferentiation of rectal adenocarcinoma with the spectrum CT scanning and spectrum analysis software. Materials and methods Totally 90 patients with rectal adenocarcinoma confirmed by pathology underwent double-phase enhanced CT scan by GSI mode, after scanning the data were transferred to GE AW 4.5 professional workstation automatically, and then the iodine and water concentration, the NIC, mean CT value of 40 keV to 140 keV(10 keV interval), and slope K values were got by using the GSI Viewer software. According to the results of pathology, the 90 patients were divided into poorly, moderately and well differentiated adenocarcinoma groups, and the various spectrum parameters between the different groups were analysis and compared with the pathology. Using the ROC curve to evaluate the differentiation diagnosis efficiency of NIC and slope K in rectal adenocarcinoma respectively. Results In the 90 cases of patients, there were 22 well differentiated adenocarcinoma,50 moderately differentiated adenocarcinoma and 18 poorly differentiated adenocarcinoma. In the arterial phase, there were statistically difference between poorly-moderately differentiated group under 40～80 keV CT values (P＜0.05); there were statistically difference between poorly-well differentiated group under 40～110 keV CT values (P<0.05); there were statistically difference between moderately-well differentiated group under 40～100 keV CT values (P＜0.05). In the venous phase, there were statistically difference between poorly-moderately differentiated group under 40-60 keV CT values (P＜0.05); there were statistically difference between poorly-well differentiated group under 40～70 keV CT values (P＜0.05); there were statistically difference between moderately-well differentiated group under 40～60 keV CT values (P＜0.05). The iodine concentration, NIC and slope K value has statistically difference both in the arterial and venous phase (P＜0.05), but no of the Water concentration (P>0.05). According to the ROC curve, the diagnostic value of NIC was close to the slope K, in the arterial phase, choosing the appropriate NIC threshold can make the sensitivity＞76% and specificity＞74%, choosing the appropriate slope K threshold can make the sensitivity＞77% and specificity＞79%. In the venous phase, choosing the appropriate NIC threshold can make the sensitivity＞77% and specificity＞72%, choosing the appropriate slope K threshold can make the sensitivity＞86% and specificity＞70%. Conclusion There were correlation between the iodine concentration, NIC, slope K and mean CT value of 40-140keV with the histodifferentiation, so the spectrum CT can provide a new imaging method for evaluating the histodifferentiation of rectal adenocarcinoma in preoperative. |
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