ObjectiveTo analyze the characteristics of magnetic resonance diffusion tensor imaging(DTI)and diffusion tensor tractography (DTIT) in patients with cerebral infarction, and explore the diagnosis values and prognosis of diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) in patients with cerebral infarction in different stages. Methods58 patients with cerebral infarction in different stages and 25 healthy volunteers were examined by magnetic resonance imaging(MRI), including conventional T1 and T2 weighted imaging, DWI and DTI. Fractional anisotropy (FA) images were reconstructed. The values of FA and apparent diffusion coefficient (ADC) were measured in the infarcted regions, corresponding contralateral normal regions and corresponding normal regions in normal control group. Results①DWI and DTI showed size of infarction focus was more accurate and clearer than that of conventional MRI; ②The FA and ADC values of the infarcted regions during superacute stage, acute stage, subacute stage and chronic stage were (0.24±0.02, 0.31 ±0.11), (0.20±0.02, 0.32±0.12), (0.18±0.02, 0.34±0.11) and (0.16±0.02, 0.37±0.13), respectively, lower than those in the contralateral corresponding regions which were (0.40±0.03, 0.70±0.21), (0.37±0.03, 0.71±0.21), (0.39±0.03, 0.72±0.22) and (0.40:±0.03, 0.72±0.23), respectively. The differences were statistically significant (P＜0.05). The FA and ADC values had no significant differences between the uninjured sides in patients with cerebral infarction and the corresponding regions in the normal control group (P＞0.05); ③The FA and ADC values in brain tissues changed regularly with the time of infarction after cerebral infarction. The FA values in the affected sides had no consistent changes as compared with the contralateral sides in the superacute stage. They increased or decreased slightly, then (during acute stage, subacute stage and chronic stage) decreased irreversibly. The ADC values in the affected sides changed with time regularly, they decreased significantly, gradually returned to normal, and then increased again. Conclusion DTI and DTT examination contribute to the diagnosis of cerebral infarction. The combination of the FA and ADC values may more accurately conduct clinical staging and evaluate the time of the occurrence of cerebral infarction.

[Objective]To compare the clinical application value of fusion imaging of ultrasound(US)and computed tomogra-phy(CT)or magnetic resonance(MR)(US-CT/MR fusion imaging)and fusion imaging of US and three-dimensional US(US-US fusion imaging)in treatment response assessment of thermal ablation combined with other surgeries and procedures.[Methods]This clinical research included patients confirmed with liver cancers that underwent thermal ablation combined with other surgeries and procedures from Aug to Dec 2015. Both US-CT/MR and US-US fusion imaging together with contrast-enhanced US was applied on the same patient to assess the treatment response of the thermal ablation during the ablation procedure. The applicable rate ,the success rate of registration and the duration required for fusion imaging were recorded and compared. Contrast-enhanced CT/MR 1-3 months after the ablation procedure was taken as the golden reference of the technical efficacy rate for ablation.[Results]67 liver can-cers in 50 patients were enrolled in this clinical research in total. The ablation of 47 lesions in 37 patients were combined with artifi-cial hydrothorax or ascites ,14 lesions in 10 patients with open surgeries and 8 lesions in 5 patients with laparoscopy surgeries. The applicable rate for US-US fusion imaging[52.5%(35/67)]was lower than that for US-CT/MR fusion imaging[98.7%(66/67)](P<0.001)while the success rate of registration for US-US fusion imaging[88.6%(31/35)]was higher than that for US-CT/MR[66.7%(44/66)](P=0.018). The duration time for US-US fusion imaging[3.8 min(2.7~10.0 min)]was significantly shorter than that for US-CT/MR fusion imaging[5.5 min(3.0 ~ 14.0 min)](P < 0.001). No major complication related to ablation was observed. The technical efficacy rate for ablation was 100%(62/62)according to the contrast-enhanced CT/MR 1-3 months after the ablation proce-dure.[Conclusion]For ablation combined with other surgeries and procedures ,US-US fusion imaging should be priority when the tumor is conspicuous in US,especially for cases combined with open surgeries while US-CT/MR fusion imaging should be selected in some cases when the tumor is inconspicuous on US.

Objective To evaluate the feasibility and efficacy of mono-modality fusion imaging using ultrasound in the intraoperative immediate evaluation of therapeutic response of liver cancer thermal ablation.Methods A total of 70 liver cancers in 53 patients that underwent thermal ablation from October to November 2015 were included in this study.Mono-modality fusion imaging using ultrasound was applied immediately after the ablation procedure to evaluate the therapeutic response of the thermal ablation.The applicable rate,the success rate of registration,the duration time,the evaluation results and the rate of supplemental ablation were recorded.Ultrasound examination was performed on the first day after ablation to evaluate the early complication.Contrast-enhanced CT/MR within 1-3 months after the procedure was regarded as the golden criteria of the treatment response.In the follow-up period,the rate of local tumor recurrence,progression-free survival and overall survival were analyzed.Results The applicable rate for mono-modality ultrasound fusion imaging is 62.9％ (44/70) while the success rate of registration is 90.9％ (40/44).The duration time for mono-modality is 2.7-7.5 min,with an average of (3.9 ± 0.9) min.Thirty-seven out of 40 liver cancers were evaluated to achieve safety margin and 3 out of 40 were not.The rate of supplemental ablation was 40％ (16/40).The rate of complete ablation was 97.3％ (36/37) according to contrast-enhanced CT/MR within 1-3 months.In the follow-up period,no local tumor recurrence was observed and the rates of intra-hepatic recurrence and overall survival were 46.7％ (14/30) and 96.7％ (29/30),respectively.Conclusions Mono-modality ultrasound fusion imaging is a convenient,feasible,safe and efficient method in the intraoperative immediate evaluation of therapeutic response of liver cancer thermal ablation.

Objective To investigate the feasibility and accuracy of three-dimensional ultrasound-ultrasound(3DUS-US)fusion imaging based on electromagnetic positioning in the assessment of ablation zone of liver tumor through experimental study in phantom models.Methods Sixteen phantom models which could be ablated and used to assess the ablation zone were established.Then,they were ablated and divided into complete ablation group(n =8)and incomplete ablation group(n =8)randomly.Their ablation effects were assessed by 3DUS-US fusion imaging.If the tumor model was assessed as incomplete ablation,the maximum thickness of the residual tumor was measured.The assessments of gross specimen were used as golden standard to validate the feasibility and accuracy of assessment of 3DUS-US fusion imaging.The success rate of registration,duration time of fusion imaging,accuracy rate of assessment and measurement error in incomplete ablation group were recorded.Results All of the 16 phantom models were produced successfully.The success rate of registration was 100% and the duration time of 3DUS-US fusion imaging was(3.9±1.0)min.The accuracy rate of assessment was 100%.There was no significant difference between the assessment of residual tumor thickness in incomplete ablation group by 3DUS-US fusion imaging and gross specimen(t=-0.814,P =0.442),and the measurement error was(1.1±0.6) mm.Conclusions 3DUS-US fusion imaging based on electromagnetic positioning is a feasible,accurate and convenient method in the assessment of ablation zone of liver tumor.It would be a new immediate precise assessment method during ablation procedure for liver tumor.

Objective To investigate the effectiveness and safety of thermal ablation of patients with 3－5 cm hepatocellular carcinoma ( HCC ) under the assistance of ultrasound fusion imaging . Methods From December 2010 to December 2017 ,76 HCC patients with 78 medium‐size ( 3 －5 cm ) lesions who underwent radiofrequency ablation ( RFA ) or microwave ablation ( M WA ) were included in the study . Ultrasound fusion imaging was used to assist the ablation procedures and assess the technical success immediately ,then guided supplementary ablation . Contrast‐enhanced CT/M R was performed one month after ablation to assess the technique efficacy rate . T he complication ,local tumor progression ( L T P ) rate were followed up . Results According to the ultrasound fusion imaging evaluation ,24 lesions ( 30 .8% , 24/78) received supplementary ablation immediately during the ablation procedure . Seventy‐one of 78 liver tumors were evaluated to achieve 5 mm ablative margin while the other 7 liver tumors were not achieved . T here were no ablation‐related deaths ,and the major complication rate was 6 .6% ( 5/76 ) .T he technique efficacy rate was 100% ( 78/78) according to the contrast‐enhanced CT/M R one‐month later . Patients were followed up from 6 to 79 months with a median time of 22 months . L T P occurred in 4 lesions and the LT P rate was 5 .1% ( 4/78) . Conclusions With the assistance of ultrasound fusion imaging ,thermal ablation of medium‐sized HCC is effective and safe w hich could achieve a higher technique efficacy rate and a lower L T P rate .

Objective:To investigate the effectiveness and safety of the coaxial needle technique in percutaneous liver biopsy for patients with coagulation function abnormalities.Methods:Clinical data of 210 patients who underwent percutaneous liver biopsy using the coaxial needle technique under ultrasound guidance from December 2018 to May 2021 in 3 centers were collected. A retrospective analysis was conducted to compare the puncture success rate, number of samples obtained, pathology qualification rate, intraoperative and postoperative bleeding rates between the group with coagulation function abnormalities and the group with normal coagulation function.Results:After propensity score matching, there were 105 patients in each group, with a puncture success rate of 100% in both groups. The pathology qualification rate was 100% for all samples.Intraoperative bleeding occurred in 78 cases (74.3%, 78/105) in the coagulation function abnormalities group and in 64 cases (61.0%, 64/105) in the normal coagulation function group, with a statistically significant difference between the two groups ( P=0.006). Postoperative bleeding occurred in 3 cases (2.9%, 3/105) in the coagulation function abnormalities group and in 0 case in the normal coagulation function group, with no statistically significant difference between the two groups ( P=0.081). Conclusions:The use of the coaxial needle technique for percutaneous liver biopsy in patients with coagulation function abnormalities not only allows for obtaining an adequate tissue sample but also demonstrates good safety.

Objective To explore the feasibility and convenience of automatic registration ultrasound-CT/MR fusion imaging based on hepatic vessel trees. Methods The PercuNav fusion imaging system of Philips Epiq 7 was used to perform ultrasound-CT/MR fusion imaging on 22 patients with focal liver lesions detected by contrast-enhanced CT or MR.Both automatic registration ultrasound-CT/MR fusion imaging based on hepatic vessel trees and the conventional ultrasound-CT/MR fusion imaging based on internal anatomic landmarks were employed for alignment in these patients.The results including the success rate of registration,duration time of initial registration,error of initial registration,number of times of fine-tuning, duration time of fine-tuning and the overall duration time of registration were compared between these two methods.Results The success rates of registration,duration time of initial registration,errors of initial registration,numbers of times of fine-tuning,duration time of fine-tuning and the overall duration time of registration for automatic registration ultrasound-CT/MR fusion imaging based on hepatic vessel trees and the conventional ultrasound-CT/MR fusion imaging based on internal anatomic landmarks were 72.73% and 95.45%,16.5 s (10~30 s) and 13 s (8~24 s),3 mm (1~14 mm) and 14 mm (2~43 mm),0 time (0 to 2 times) and 1 time (0~3 times),0 s(0~46 s) and 30 s (0~88 s),and 20 s (12~61 s) and 42 s (9~102 s),successively and respectively. There was no statistically significant difference in the success rates between these two methods ( P >0.05).The duration time of initial registration of conventional method was less than that of automatic registration method( P <0.05).The error of initial registration,number of times of fine-tuning,duration time of fine-tuning and the overall duration time of registration of automatic registration method were superior to those of conventional method ( P < 0.05).Conclusions Automatic registration ultrasound-CT/MR fusion imaging based on hepatic vessel trees is feasible. It is also more convenient than conventional ultrasound-CT/MR fusion imaging based on internal anatomic landmarks.

Objective To discuss the value of contrast-enhanced ultrasound (CEUS) in evaluating gallbladder injury during the thermal ablation of liver tumors adjacent to the gallbladder. Methods From January 2016 to March 2017, 40 patients with 42 hepatic tumors adjacent to the gallbladder who underwent ultrasonography-guided percutaneous microwave ablation or radiofrequency ablation in the Third Affiliated Hospital of Sun Yat-sen University were included in the study. Ultrasonography (US) was used to assess the change of gallbladder wall thickness before and after procedure. CEUS was used to assess the perfusion of gallbladder wall and determine the gallbladder injury immediately after ablation. Patients with bad perfusion of gallbladder wall accept combined treatment with cholecystectomy. The safety and therapeutic efficacy of the procedures were assessed in follow-up examinations. The change of gallbladder wallthickness were compared by signed ranks sum test. Results Assessed by US immediately after the ablations, gallbladder wall thickening adjacent to the ablated zone was noted in 8 of 40 patients. According the results of CEUS immediately after ablations, 38 patients was evaluated with good perfusion of gallbladder wall and 2 patients was evaluated with bad perfusion, who were treated with cholecystectomy. Perforation of the gallbladder was found in one of them. However, the necrosis of serosal tissue in gallbladder wall was confirmed by postoperative pathology. Another 4 patients with multiple gallbladder stones were also treated with cholecystectomy. Gallbladder wall thickening developed in six patients (17.6%) within 3 days after the ablation. Wall thickening showed complete disappearance on subsequent follow up US in 4 patients, and showed existence in 2 patients. However, complications related to the ablation such as acute cholecystitis and gallbladder perforation were not noted in 34 patients without cholecystectomy. There was significant difference in gallbladder wall thickness between preoperative and intraoperative assessment [5.00 mm (4.00-6.25 mm) vs 3.50 mm (3.00-5.00 mm), Z=-3.741, P < 0.001], as well as between preoperative and postoperative assessment[5.0 mm(3.0-8.0 mm)vs 3.5 mm(3.0-5.0 mm),Z=-3.735,P < 0.001].The complete ablation rate was 97.6% (41/42) based on one-month follow-up CT or MR imaging. Local tumor progression was not found in these completely ablated tumors during the follow-up period. Conclusion Immediate post-procedural CEUS can be used to demonstrate the perfusion of gallbladder wall in US-guided ablation of hepatic tumors adjacent to the gallbladder, which is helpful to determine thermal injury of the gallbladder.