Objective To explore the application value of turbo spin echo-diffusion weighted imaging(TSE-DWI)sequences in 3.0 T rectal cancer MRI examination by comparing the image quality difference be-tween TSE-DWI and conventional echo planar imaging-diffusion weighted imaging(EPI-DWI)sequences.Methods The medical records of forty-two patients with newly diagnosed rectal cancer confirmed by colonos-copy were prospectively collected.All patients simultaneously underwent both TSE-DWI and EPI-DWI se-quence scans.The image quality of the two groups performed the subjective evaluation(lesion contrast,mag-netic susceptibility artifacts,geometric distortion)and objective evaluation[signal-to-noise ratio(SNR),con-trast-to-noise ratio(CNR),contrast,etc].Results In the subjective evaluation,compared with the conven-tional EPI-DWI sequences,the proportions of subjective score 3-5 points for the lesion contrast,magnetic susceptibility artifacts and geometric distortion in the TSE-DWI sequences lesions were over 95％,which all were higher the conventional EPI-DWI sequences;among them,the differences in the subjective scoring results of magnetic susceptibility artifacts and geometric deformation were statistically significant(x2=12.464,5.610,P＜0.05),while there was no statistical significance in lesion contrast(x2=2.363,P＞0.05).In the objective evaluation,SNR and CNR in the TSE-DWI sequences all were higher than those in the conventional EPI-DWI sequences,in which the difference in CNR was statistically significant(Z=—5.645,P＜0.05),while the difference in SNR was not statistically significant(Z=—1.057,P＞0.05).The contrast in the TSE-DWI sequences was lower than that in the conventional EPI-DWI sequences,and the difference was statistical-ly significant(t=3.012,P＜0.05).Conclusion The TSE-DWI sequence images have small geometric de-formation and few magnetic susceptibility artifacts,the image quality is superior to the EPI-DWI sequences.Especially in 3.0T rectal cancer MRI plain scan,the patients with gas accumulation in the intestinal lumen of rectal lesion could directly adopt the TSE-DWI sequences by replacing the conventional EPI-DWI sequences in order to increase the clinical application efficiency and image quality.

Objective:To explore the feasibility of dual-energy CT (DECT) in the evaluation of liver iodine concentration in patients on long-term oral amiodarone treatment (≥12 months).Methods:Eighteen subjects undergoing abdominal dual-energy CT who met the criterion in January 2017 were collected as a control group. Twenty-seven patients who received oral amiodarone treatment for more than 12 months from January 2017 to May 2019 were enrolled as an experimental group. The difference of CT value and iodine concentration of liver, pancreas and spleen in 140 kV, 100 kV and VNC images between experimental and control groups were measured and analyzed. The correlation between liver CT value and liver iodine concentration was analyzed by Spearman correlation.Results:The concentrations of iodine in the liver, pancreas and spleen of the experimental group were 0.2 (0.2, 0.4), 0.1 (0.1, 0.2) and 0.2 (0.1, 0.2) mg/ml, and those in the control group were 0.2 (0.1， 0.2), 0.1 (0.1, 0.2) and 0.1 (0.1, 0.2) mg/ml. The difference in the concentration of iodine of the liver was statistically significant ( Z=-3.354, P<0.05), however there was no significant difference in the concentration of pancreas and spleen between the two groups ( Z=-0.179 and -1.590, P>0.05). The CT values of 100 kV, 140 kV, VNC images in the experimental group [(74±18)， (70±10) and (71±5) HU] were higher than those in the control group [(60±6)， (59±6) and (62±6) HU], and the differences were statistically significant ( t=3.310, 4.205 and 5.241, P<0.05). There was a positive correlation between the CT value of 140 kV image and iodine concentration ( r=0.410, P<0.05). In the experimental group, the time difference of taking amiodarone was statistically significant ( P<0.05). Conclusions:DECT can be used to quantitatively measure the liver iodine concentration of patients with long-term oral amiodarone, and provides some biological indicators for the assessment of amiodarone induced liver injury.