Objective To investigate the frequency and dose of X-ray computed tomography (CT) medical exposure in Shantou City, and to evaluate the collective effective dose burden of residents caused by CT medical exposure. Methods The study subjects were selected using the stratified random sampling method from CT scanners in all medical institutions in Shantou City in 2020. CT application units were divided into the four tiers of municipal hospitals, district hospitals, subdistrict hospitals, and private hospitals, and 50% of the hospitals in each tier were randomly selected according to the number of hospitals in the tier. The study analyzed CT dose index results, CT scanning standard conditions, and the distribution of characteristic doses of medical exposure to evaluate the dose burden of residents in Shantou City caused by CT medical exposure. Results There were 51 CT scanners in medical institutions in Shantou City. By the end of 2020, the average number of CT scanners per million population was 9.30, and the frequency of CT medical exposure was 135.24 per 1000 population. Jinping District had the highest number of CT scanners per million population (23.2), while Chaoyang District had the lowest number of CT scanners per million population (3.6). The median and range of effective doses for different scan regions were 1.65 (0.76, 4.49) mSv in the head, 4.12 (1.90, 53.21) mSv in the chest, 5.96 (2.68, 10.25) mSv in the abdomen, and 10.30 (4.12, 12.67) mSv in the lumbar spine. By the end of 2020, the effective dose to the public in Shantou City was 6080.67 Sv·person, and the average annual effective dose per person was 1.10 mSv. Conclusion Medical exposure is the most important factor affecting resident dose burden, particularly the overuse of medical exposure examinations. CT examination is the most significant component of medical exposure causing resident dose burden. Reducing unnecessary medical exposure, ensuring the rational use of CT examination, and properly utilizing personal protective equipment are effective measures to minimize the dose burden on examinees.

Objective:To investigate the diagnostic value of contrast-enhanced ultrasound（CEUS）in solid pseudopapillary tumor of pancreas（SPTP），summarize the CEUS characteristics of SPTP，and to compare its CEUS enhancement with contrast-enhanced computed tomography（CECT）.Methods:In this retrospective study，baseline characteristics，basic ultrasound and CEUS images，CECT images of 70 patients diagnosed as SPTP from January 2009 to August 2023 were collected. Images were analyzed for extraction of key features and diagnostic accuracies of both CEUS and CECT were calculated. The relationships between ultrasound features and lesion size of SPTP were analyzed by Point-Biserial correlation analysis and Student t test. The diagnostic accuracy was compared by Mann-Whitney U test. Results:Iso-enhancement（55.7%，39/70）was commonly appeared in the early phase of CEUS for SPTP，while hypo-enhancement（74.3%，52/70）was the most common in the late phase. And the most common enhancement pattern was iso-hypo enhancement（41.4%，29/70）. Lesion membrane enhancement（47.1%，33/70），intralesional compartmentalization（28.6%，20/70），and intralesional vessels（25.7%，18/70）were the 3 typical signs found in CEUS for SPTP，which were correlated with lesion size（ P＜0.001）. Differences were found between the enhancement pattern of SPTP in CEUS and CECT，in which the most common enhancement patterns were hypo-hypo enhancement（41.4%，24/58）and iso-iso enhancement（29.3%，17/58）along with progressive enhancement. The diagnostic accuracies of CEUS and CECT were 71.4% and 74.1% respectively without statistically significant difference（ P=0.733）. Conclusions:CEUS shows high application value in the diagnosis of SPTP，and the accuracy of CEUS is comparable to that of CECT.

Objective:To investigate the diagnostic value of contrast-enhanced ultrasound（CEUS）in solid pseudopapillary tumor of pancreas（SPTP），summarize the CEUS characteristics of SPTP，and to compare its CEUS enhancement with contrast-enhanced computed tomography（CECT）.Methods:In this retrospective study，baseline characteristics，basic ultrasound and CEUS images，CECT images of 70 patients diagnosed as SPTP from January 2009 to August 2023 were collected. Images were analyzed for extraction of key features and diagnostic accuracies of both CEUS and CECT were calculated. The relationships between ultrasound features and lesion size of SPTP were analyzed by Point-Biserial correlation analysis and Student t test. The diagnostic accuracy was compared by Mann-Whitney U test. Results:Iso-enhancement（55.7%，39/70）was commonly appeared in the early phase of CEUS for SPTP，while hypo-enhancement（74.3%，52/70）was the most common in the late phase. And the most common enhancement pattern was iso-hypo enhancement（41.4%，29/70）. Lesion membrane enhancement（47.1%，33/70），intralesional compartmentalization（28.6%，20/70），and intralesional vessels（25.7%，18/70）were the 3 typical signs found in CEUS for SPTP，which were correlated with lesion size（ P＜0.001）. Differences were found between the enhancement pattern of SPTP in CEUS and CECT，in which the most common enhancement patterns were hypo-hypo enhancement（41.4%，24/58）and iso-iso enhancement（29.3%，17/58）along with progressive enhancement. The diagnostic accuracies of CEUS and CECT were 71.4% and 74.1% respectively without statistically significant difference（ P=0.733）. Conclusions:CEUS shows high application value in the diagnosis of SPTP，and the accuracy of CEUS is comparable to that of CECT.

Objective:To analyze the gray-scale ultrasound and contrast-enhanced ultrasound features in secondary hyperparathyroidism (SHPT) to construct a clinical and ultrasound-based model, and to investigate the relationship between this model and serum intact parathyroid hormone(iPTH) level in order to find proper indicators for evaluation of the severity of SHPT.Methods:From February 2016 to March 2021, a total of 59 SHPT patients with 181 parathyroid glands (PTGs) admitted to the First Affiliated Hospital of Sun Yat-Sen University were enrolled. Gray-scale ultrasound and contrast-enhanced ultrasound were performed in every participant. Patients were divided into low-iPTH group ( iPTH<800 ng/L) and high-iPTH group (iPTH≥800 ng/L) according to the serum iPTH level. The characteristics of gray-scale ultrasonic imaging and contrast-enhanced ultrasonic imaging were analyzed by 2 sonographers.Biochemical parameters were collected and combined with ultrasonic characteristics to construct the clinical and ultrasound-based model. The relationship between the model and serum iPTH level was analyzed by multivariate linear regression (stepwise). Independent influencing factors on serum iPTH level was investigated in SHPT patients without iPTH-reducing drugs using history.Results:There were 19 patients in low-iPTH group and 40 patients in high-iPTH group.Serum calcium, serum phosphorus, serum creatinine, PTG number, total PTG volume, blood scores, calcification and cysts scores, CEUS scores (washing-in phase and washing-out phase) were significantly different between two groups(all P<0.05). The multivariate linear regression (stepwise) showed that serum phosphorus, total PTG volume and blood scores were independently related with serum iPTH level (standardized β coefficient were 0.387, 0.254 and 0.242 respectively; all P<0.05). Conclusions:Serum phosphorus, total PTG volume and blood scores are independent influencing factors on serum iPTH level. Ultrasonography combined with clinical parameters can help evaluate the severity of SHPT more accurately.

Objective:To establish a model based on two-dimensional shear wave elastography (2D-SWE) for predicting post-hepatectomy liver failure (PHLF) among patients with hepatocellular carcinoma (HCC).Methods:One hundred and one consecutive patients with HCC undergoing hepatectomy from August 2018 to July 2019 were enrolled prospectively in the First Affiliated Hospital of Sun Yat-Sen University. Laboratory tests, shear wave elastography in liver parenchyma, and abdominal contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI) were performed preoperatively. Liver functional reserve, liver stiffness (LS), and tumor-related imaging parameters were assessed. PHLF was defined according to the definition of International Study Group of Liver Surgery Recommendations (ISGLS). A predictive model was developed by logistic regression analysis and the performance thereof was evaluated by receiver operating characteristic (ROC) curve analysis and Hosmer-Lemeshow test.Results:PHLF occurred in 39 patients (38.9%). Logistic regression analysis identified that international normalized ratio ( OR=1.09, P=0.026), LS( OR=1.297, P=0.004) and the largest nodule diameter( OR=1.191, P=0.015) were independent risk factors of PHLF.The area under curve (AUC) of the model was 0.842(95% CI =0.763-0.921), which was significantly higher than those of ALBI score, MELD score and Child-Pugh score (AUC 0.626-0.688, P<0.05). The model also showed good calibration in Hosmer-Lemeshow test ( P=0.498). Conclusions:A model based on 2D-SWE provides good preoperative prediction of PHLF among patients with HCC, which might have the potential in better customizing treatment strategy in those patients.

Objective:To explore the value of shear wave elastography imaging(SWE) in the diagnosis of renal allograft fibrosis and analyze its advantages and limitations.Methods:The renal allograft of 61 patients who underwent renal allograft biopsy from June 2019 to April 2020 in the First Affiliated Hospital of Sun Yat-sen University were included in this study. According to the Banff classification, there were 51 patients with mild-degree fibration(interstitial fibrosis/tubular atrophy, IFTA 0-Ⅰ), and 29 patients with moderate or severe-degree fibration(IFTA Ⅱ-Ⅲ). Two-dimensional ultrasound, color Doppler flow imaging, SWE and kidney function test performed. All the results were compared between the two groups. Diagnostic performance was evaluated by receiver operating characteristic (ROC) curve using pathology as gold standard. The sensitivity, specificity, positive predictive value and negative predictive value were calculated for the diagnosis of moderate or severe-degree fibration.Results:Compared to mild-degree fibration group, creatinine( P<0.001), glomerular filtration rate( P<0.001), RI of arcuate arteries( P=0.022) and SWE value( P<0.001) significantly increased in the moderate or severe-degree fibration group. There were significant correlations between IFTA and creatinine ( r s=0.488, P<0.001), glomerular filtration rate ( r s=-0.452, P<0.001), RI of arcuate arteries( r s=0.228, P=0.042), SWE value( r s=0.584, P<0.001). Taking the cutoff value of SWE value deduced by ROC curve as 21.7 kPa, the area under ROC curve was 0.827. The sensitivity, specificity, positive predictive value and negative predictive value were 86.2%, 74.5%, 61.0% and 89.7%, respectively. Conclusions:There is a good correlation between the SWE value and the degree of fibrosis in the transplanted kidney. SWE can be used to distinguish mild from moderate or severe fibrosis of renal allograft, providing a potential noninvasive method for the assessment of kidney allograft fibration.

Objective To compare three-dimensional contrast-enhanced ultrasound ( 3DCEUS) fusion imaging and computed tomography ( CT ) fusion imaging in evaluating ablation margin ( AM ) after radiofrequency ablation ( RFA) for hepatocellular carcinoma ( HCC) . Methods The 3DCEUS images of 60 patients before and after RFA were collected . The AM was evaluated by the self-developed 3DCEUS fusion imaging technique . The consistency of AM evaluation was compared between 3DCEUS and CT fusion imaging . The risk factors of local tumor progression ( LTP) including AM were analyzed . Results The registration success rate of 3DCEUS fusion imaging was 96 .7％ ( 58/60) . Thirty-one cases were in the AM<5 mm group ,and 27 cases were in the AM ≥5 mm group . The consistency of AM evaluation between 3DCEUS and CT fusion imaging was good ( Kappa coefficient = 0 .895 , P < 0 .001) . During a follow-up period ranging 4 .2 to 18 months ,LTP was identified in 5 tumors (8 .6％ ,5/58) .The incidence of LTP with the AM<5 mm was higher than that with the AM ≥5 mm ( P =0 .033) . Conclusions 3DCEUS fusion imaging is feasible for AM evaluation immediately after RFA with high consistency with CT fusion imaging . AM<5 mm evaluated on 3DCEUS fusion immediately after RFA is a risk factor for LTP .

Objective To investigate the utility of virtual endoscopy ultrasound Fly-Thru in the diagnosis of obstructive bile duct diseases.Methods One-hundred patients with obstructed bile duct diseases underwent Fly-Thru examination.All Fly-Thru images were reviewed by two radiologists with different experience.The capabilities of Fly-Thru for bile duct obstructive degree evaluation and distinguishing malignant lesion from benign one were assessed respectively.Results The accuracy and sensitivity of Fly-Thru image in obstruction degree evaluation were 70.59％ and 89.2％ (95％CI 74.6％-96.9％).The diagnosis accuracy of 2DUS for lesion characteristics increased from 80％ to 84％,accompany with Fly-Thru images,especially for lesions in common bile duct from 77.2％ to 86.0％ (x2 =14.399,P =0.001).Conclusions The virtual endoscopy ultrasound Fly-Thru is only partly capable to display the obstructed degree of some bile ducts,but it can improve the diagnostic accuracy of common bile duct diseases.

Objective To summarize the first experience with ultrasound-guided percutaneous ab lation treatment (PAT) for recurrent hepatoblastoma (HB) after liver resection in children.Methods From August 2013 to April 2015,PAT was used to treat 6 children with a total of 9 recurrent HB,including 5 patients with 8 tumors in the liver and 1 patient with 1 tumor in the lung.The mean size of ablated tumors was (1.5 ± 0.8) cm,and the tumor size range was 0.7 cm to 3.1 cm.Results Four patients were performed percutaneous radiofrequency ablation (RFA) for recurrent HB;and 2 patients were performed percutaneous ethanol injection (PEI).Ablation success was achieved in all patients (6/6,100％).The complete ablation rate after the first ablation session was 88.9％ (8/9) on a tumor-by-tumor basis.Only 1 patient developed a fever with temperature ＞ 39 ℃;it was resolved by conservative therapy.During the follow-up period of 5-30 months,3 patients died to tumor progression.The 1-and 2-year overall survival rates after ablation were 83.3％ and 41.7％,respectively.Conclusions PAT is a safe and promising therapy for children with recurrent HB after liver resection,and further investigation in large-scale randomized clinical trials is required to determine its role in the treatment of this disease.

Objective To retrospectively compare the safety and local efficacy of multiple-electrode switching based radiofrequency ablation (RFA) and the conventional RFA in treating single early-stage hepatocellular carcinoma (HCC).Methods A total of 82 patients with single early-stage HCC received either RFA with a multiple-electrode switching system (n =43) or conventional RFA (n =39) as the first-line treatment.The rate of initial local complete response,major complications and local tumor progression (LTP) were compared between two groups.Results The total ablation time was significantly shorter in the switching-RFA group [(16.7 ± 3.4) mins] than in the conventional RFA group [(29.8 ± 10.4) mins] (P ＜ 0.05).The rate of initial local complete response was 100％ (43/43) in the switching-RFA group and 94.9％ (37/39) in the conventional RFA group (P ＞0.05).After a mean follow-up period of (26.4 ± 21.8)months (ranging 3.0-91.6 months),the rates of LTP in the switching-RFA group and conventional RFA group were 16.3％ (7/43) and 17.9％ (7/39),respectively.The LTP rates in two groups were 16.1％ versus 11.2％ atyear1,and20.5％ versus 20.6％ at year2 (P=0.666).Conclusions The multiple-electrode switching based RFA is safe and effective with shorter ablation time in treating single early-stage hepatocellular carcinoma.