Interplay of RUNX2 and KLF4 in initial commitment of odontoblast differentiation.

Odontoblast differentiation is a key process in dentin formation. Mouse dental papilla cells (mDPCs) are pivotal in dentinogenesis through their differentiation into odontoblasts. Odontoblast differentiation is intricately controlled by transcription factors (TFs) in a spatiotemporal manner. Previous research explored the role of RUNX2 and KLF4 in odontoblast lineage commitment, respectively. Building on bioinformatics analysis of our previous ATAC-seq profiling, we hypothesized that KLF4 potentially collaborates with RUNX2 to exert its biological role. To investigate the synergistic effect of multiple TFs in odontoblastic differentiation, we first examined the spatiotemporal expression patterns of RUNX2 and KLF4 in dental papilla at the bell stage using immunostaining techniques. Notably, RUNX2 and KLF4 demonstrated colocalization in preodontoblast. Further, immunoprecipitation and proximity ligation assays verified the interaction between RUNX2 and KLF4 in vitro. Specifically, the C-terminus of RUNX2 was identified as the interacting domain with KLF4. Functional implications of this interaction were investigated using small hairpin RNA-mediated knockdown of Runx2, Klf4, or both. Western blot analysis revealed a marked decrease in DSPP expression, an odontoblast differentiation marker, particularly in the double knockdown condition. Additionally, alizarin red S staining indicated significantly reduced mineralized nodule formation in this group. Collectively, our findings highlight the synergistic interaction between RUNX2 and KLF4 in promoting odontoblast differentiation from mDPCs. This study contributes to a more comprehensive understanding of the regulatory network of TFs governing odontoblast differentiation.

Comparing Sonazoid contrast-enhanced ultrasound to contrast-enhanced CT and MRI for differentially diagnosing renal lesions: a prospective multicenter study.

PURPOSE: To evaluate the diagnostic performance of contrast-enhanced (CE) ultrasound using Sonazoid (SNZ-CEUS) by comparing with contrast-enhanced computed tomography (CE-CT) and contrast-enhanced magnetic resonance imaging (CE-MRI) for differentiating benign and malignant renal masses. MATERIALS AND METHODS: 306 consecutive patients (from 7 centers) with renal masses (40 benign tumors, 266 malignant tumors) diagnosed by both SNZ-CEUS, CE-CT or CE-MRI were enrolled between September 2020 and February 2021. The examinations were performed within 7 days, but the sequence was not fixed. Histologic results were available for 301 of 306 (98.37%) lesions and 5 lesions were considered benign after at least 2 year follow-up without change in size and image characteristics. The diagnostic performances were evaluated by sensitivity, specificity, positive predictive value, negative predictive value, and compared by McNemar's test. RESULTS: In the head-to-head comparison, SNZ-CEUS and CE-MRI had comparable sensitivity (95.60 vs. 94.51%, P = 0.997), specificity (65.22 vs. 73.91%, P = 0.752), positive predictive value (91.58 vs. 93.48%) and negative predictive value (78.95 vs. 77.27%); SNZ-CEUS and CE-CT showed similar sensitivity (97.31 vs. 96.24%, P = 0.724); however, SNZ-CEUS had relatively lower than specificity than CE-CT (59.09 vs. 68.18%, P = 0.683). For nodules > 4 cm, CE-MRI demonstrated higher specificity than SNZ-CEUS (90.91 vs. 72.73%, P = 0.617) without compromise the sensitivity. CONCLUSIONS: SNZ-CEUS, CE-CT, and CE-MRI demonstrate desirable and comparable sensitivity for the differentiation of renal mass. However, the specificity of all three imaging modalities is not satisfactory. SNZ-CEUS may be a suitable alternative modality for patients with renal dysfunction and those allergic to gadolinium or iodine-based agents.

Application of the ankle pump method in a sitting position to evaluate calf perforating veins by color Doppler ultrasound.

OBJECTIVE: We investigated the feasibility and efficacy of assessing calf perforating veins (PVs) using the ankle pump in a sitting position (AP-sit) method by color Doppler ultrasound. METHODS: We performed a multicenter prospective clinical trial between November 2022 and October 2023. Eligible patients with chronic venous disease and healthy controls were enrolled. The calf PVs were assessed using three different methods: manual compression in a standing position, manual compression in a sitting position, and AP-sit method. The reflux durations and detection rate of incompetent PVs (IPVs) were compared among the three methods. The number and diameter of calf PVs and distribution of IPVs were analyzed. RESULTS: A total of 50 patients with chronic venous disease and 50 healthy controls were included. There were 173 calves analyzed, including 97 healthy calves and 76 calves with chronic venous disease. The number of PVs per calf was higher in the diseased calves (median, 7.0; interquartile range [IQR], 6.0-8.0) than in the healthy calves (median, 5.0; IQR, 3.0-6.0; P < .001). The diameter of IPVs (median, 2.3 mm; IQR, 2.0-3.1 mm) was larger than that of competent PVs (median, 1.4 mm; IQR, 1.2-1.7 mm). Most of the IPVs (78.8%) were located in the medial and posterior middle of the calf. The reflux duration induced by the AP-sit method was greater than that induced by the manual compression methods (P < .001). Although the AP-sit method had a higher detection rate (92.0%) of IPVs than the manual compression methods (71.7% and 74.3% for standing and sitting, respectively; P < .001), especially in the distal lower leg, the manual compression methods found IPVs not found using the AP-sit method. CONCLUSIONS: Diseased calves with chronic venous disease have more PVs than do healthy calves. IPVs are commonly larger than competent PVs, with most IPVs located in the medial and posterior middle of the calf. Most importantly, the AP-sit method provides a convenient and effective approach for assessing the calf PVs, especially those located in the distal calf, as an alternative or complementary method to traditional manual compression, which is valuable in the daily practice of sonographers.

Comparison between spleen and liver stiffness measurements by sound touch elastography for diagnosing cirrhosis at different aminotransferase levels: a prospective multicenter study.

OBJECTIVES: To compare the performance of spleen stiffness measurement (SSM) and liver stiffness measurement (LSM) by sound touch elastography (STE) for the diagnosis of cirrhosis at different alanine aminotransferase (ALT) levels, and to compare the applicability and repeatability of SSM with LSM performed by STE, a new two-dimensional shear wave elastography technology. METHODS: This prospective multicenter study included 25 centers and recruited chronic hepatitis B (CHB) patients with liver biopsy between May 2018 and November 2019. All patients underwent LSM and SSM by STE. Success and reliability rates were calculated and compared. Intra-observer agreement was assessed using intraclass correlation coefficients (ICCs). Differences between areas under the receiver operating characteristic curves (AUCs) of LSMs and SSMs at different ALT levels were compared using the Delong test. RESULTS: Among 603 CHB patients, the success and reliability rates of SSM were 94.53% (570/603) and 85.74% (517/603), respectively, which were similar to those of LSM (p > 0.05), respectively. The ICC for intra-observer agreements of SSM was 0.964 (p < 0.001). In the total cohort, ALT ≤ 2 × upper limit of normal (ULN) group, and A0-1 group, the AUCs of SSMs were significantly lower than those of LSMs for the diagnosis of cirrhosis (p < 0.001). In the ALT > 2 × ULN group and A2-3 group, the AUC of SSM improved and was not significantly different from that of LSM (p = 0.342, p = 0.510, respectively). CONCLUSIONS: SSM by STE achieved applicability and repeatability equivalent to those of LSM. SSM might be a good substitute to LSM in patients with high ALT levels. KEY POINTS: • Spleen stiffness measurement performed by sound touch elastography was proven to have similar applicability and repeatability to liver stiffness measurement in this prospective multicenter study. • Spleen stiffness measurement demonstrated a poorer diagnostic performance for cirrhosis compared with liver stiffness measurement in the total cohort and low ALT level group, yet it showed a similar diagnostic performance to liver stiffness measurement in patients with high ALT levels.

Usefulness of New Shear Wave Elastography Technique for Noninvasive Assessment of Liver Fibrosis in Patients with Chronic Hepatitis B: A Prospective Multicenter Study.

PURPOSE: To explore the usefulness of liver stiffness measurements (LSMs) by sound touch elastography (STE) and sound touch quantification (STQ) in chronic hepatitis B (CHB) patients for staging fibrosis. METHODS: This prospective multicenter study recruited normal volunteers and CHB patients between May 2018 and October 2019. The volunteers underwent LSM by STE and supersonic shear imaging (SSI) or by STQ and acoustic radiation force impulse imaging (ARFI). CHB patients underwent liver biopsy and LSM by both STE/STQ. The areas under the receiver operating characteristic curves (AUCs) for staging fibrosis were calculated. RESULTS: Overall, 97 volunteers and 524 CHB patients were finally eligible for the study. The successful STE and STQ measurement rates were both 100 % in volunteers and 99.4 % in CHB patients. The intraclass correlation coefficients (ICCs) for the intra-observer stability of STE and STQ (0.94; 0.90) were similar to those of SSI and ARFI (0.95; 0.87), respectively. STE and STQ showed better accuracy than the aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis-4 index (FIB-4) (AUC: 0.87 vs 0.86 vs 0.73 vs 0.77) in staging cirrhosis. However, both STE and STQ were not superior to APRI and FIB-4 in staging significant fibrosis (AUC: 0.76 vs 0.73 vs 0.70 vs 0.71, all P-values > 0.05). CONCLUSION: STE and STQ are convenient techniques with a reliable LSM value. They have a similar diagnostic performance and are superior to serum biomarkers in staging cirrhosis in CHB patients.

Lower Leg Muscle Stiffness on Two-Dimensional Shear Wave Elastography in Subjects With Medial Tibial Stress Syndrome.

OBJECTIVES: We aimed to explore, which muscle stiffness changes may be related to medial tibial stress syndrome (MTSS) and the correlation between the medial tibial periosteal thickness and lower leg muscle stiffness. METHODS: This study included 63 subjects distributed into 3 groups: the symptomless group, the MTSS group, and the control group. The lower leg muscle stiffness of the tibialis anterior (TA), extensor digitorum longus (EDL), peroneus longus (PL), soleus (SOL), lateral gastrocnemius (LG), medial gastrocnemius (MG), tibialis posterior (TP), and flexor digitorum longus (FDL) in the 3 groups was obtained by two-dimensional shear wave elastography. Differences in the muscle stiffness and medial tibial periosteal thickness in the 3 groups were determined by one-way analysis of variance (ANOVA) and least significant difference tests. The relationships between the periosteal thickness and the muscle stiffness were assessed using Pearson correlations. RESULTS: The shear wave velocity (SWV) of all lower leg muscles except the EDL was higher in the symptomless and MTSS groups than in the control group (TA, P = .001; PL, P = .006; SOL, P < .001; LG, P < .001; MG, P < .001; TP, P < .001; FDL, P = .013; and ANOVA). A significant difference was found in the SWV of the SOL, TP, and FDL between the control and symptomless groups (P = .041, P < .001, and P = .013, respectively). Moreover, the medial tibial periosteum was thickened after running training, and its thickness was positively correlated with muscle stiffness. CONCLUSION: The medial tibia periosteal thickness is positively correlated with the lower leg muscles stiffness. Changes in SOL, TP, and FDL stiffness may be related to the occurrence of MTSS.

Single-cell characterization of monolayer cultured human dental pulp stem cells with enhanced differentiation capacity.

Human dental pulp stem cells (hDPSCs) are easily obtained multipotent cells, however, their potential value in regenerative medicine is hindered by the phenotypic and functional changes after conventional monolayer expansion. Here, we employed single-cell RNA sequencing (scRNA-seq) to comprehensively study the transcriptional difference between the freshly isolated and monolayer cultured DPSCs. The cell cluster analysis based on our scRNA-seq data showed that monolayer culture resulted in a significant cellular composition switch compared to the freshly isolated DPSCs. However, one subpopulation, characterized as MCAM(+)JAG(+)PDGFRA(-), maintained the most transcriptional characteristics compared to their freshly isolated counterparts. Notably, immunofluorescent staining revealed that the MCAM(+)JAG(+)PDGFRA(-) hDPSCs uniquely located in the perivascular region of human dental pulp tissue. Flow-cytometry analysis confirmed that their proportion remained relatively stable (~2%) regardless of physiological senescence or dental caries. Consistent with the annotation of scRNA-seq data, MCAM(+)JAG(+)PDGFRA(-) hDPSCs showed higher proliferation capacity and enhanced in vitro multilineage differentiation potentials (osteogenic, chondrogenic and adipogenic) compared with their counterparts PDGFRA(+) subpopulation. Furthermore, the MCAM(+)JAG(+)PDGFRA(-) hDPSCs showed enhanced bone tissue formation and adipose tissue formation after 4-week subcutaneous implantation in nude mice. Taken together, our study for the first time revealed the cellular composition switch of monolayer cultured hDPSCs compared to the freshly isolated hDPSCs. After in vitro expansion, the MCAM(+)JAG(+)PDGFRA(-) subpopulation resembled the most transcriptional characteristics of fresh hDPSCs which may be beneficial for further tissue regeneration applications.

Noninvasive Assessment of Interstitial Fibrosis and Tubular Atrophy in Renal Transplant by Combining Point-Shear Wave Elastography and Estimated Glomerular Filtration Rate.

The purpose of this study was to evaluate the feasibility of the combination of point-shear wave elastography (p-SWE) and estimated glomerular filtration rate (eGFR) for assessing different stages of interstitial fibrosis and tubular atrophy (IF/TA) in patients with chronic renal allograft dysfunction (CAD). From September 2020 to August 2021, 47 patients who underwent renal biopsy and p-SWE examinations were consecutively enrolled in this study. The areas under the receiver operating characteristic curves (AUCs) were calculated to evaluate overall accuracy and to identify the optimal cutoff values for different IF/TA stages. A total of 43 patients were enrolled in this study. The renal cortical stiffness and eGFR showed a significant difference between IF/TA Grade 0-1 and Grade 2-3 (p < 0.001). Additionally, renal stiffness and eGFR were independent predictors for moderate-to-severe IF/TA (Grade ≥ 2) according to multiple logistic regression analysis. The combination of p-SWE and eGFR, with an optimal cutoff value of -1.63, was superior to eGFR alone in assessing moderate-to-severe interstitial fibrosis (AUC, 0.86 vs. 0.72, p = 0.02) or tubular atrophy (AUC, 0.88 vs. 0.74, p = 0.02). There was no difference between p-SWE and eGFR in assessing moderate-to-severe IF/TA (AUC, 0.85 vs. 0.79, p = 0.61). Therefore, combining p-SWE and eGFR is worthy of clinical popularization and application.

Deep learning Radiomics of shear wave elastography significantly improved diagnostic performance for assessing liver fibrosis in chronic hepatitis B: a prospective multicentre study.

OBJECTIVE: We aimed to evaluate the performance of the newly developed deep learning Radiomics of elastography (DLRE) for assessing liver fibrosis stages. DLRE adopts the radiomic strategy for quantitative analysis of the heterogeneity in two-dimensional shear wave elastography (2D-SWE) images. DESIGN: A prospective multicentre study was conducted to assess its accuracy in patients with chronic hepatitis B, in comparison with 2D-SWE, aspartate transaminase-to-platelet ratio index and fibrosis index based on four factors, by using liver biopsy as the reference standard. Its accuracy and robustness were also investigated by applying different number of acquisitions and different training cohorts, respectively. Data of 654 potentially eligible patients were prospectively enrolled from 12 hospitals, and finally 398 patients with 1990 images were included. Analysis of receiver operating characteristic (ROC) curves was performed to calculate the optimal area under the ROC curve (AUC) for cirrhosis (F4), advanced fibrosis (≥F3) and significance fibrosis (≥F2). RESULTS: AUCs of DLRE were 0.97 for F4 (95% CI 0.94 to 0.99), 0.98 for ≥F3 (95% CI 0.96 to 1.00) and 0.85 (95% CI 0.81 to 0.89) for ≥F2, which were significantly better than other methods except 2D-SWE in ≥F2. Its diagnostic accuracy improved as more images (especially ≥3 images) were acquired from each individual. No significant variation of the performance was found if different training cohorts were applied. CONCLUSION: DLRE shows the best overall performance in predicting liver fibrosis stages compared with 2D-SWE and biomarkers. It is valuable and practical for the non-invasive accurate diagnosis of liver fibrosis stages in HBV-infected patients. TRIAL REGISTRATION NUMBER: NCT02313649; Post-results.

Liver Fibrosis with Two-dimensional US Shear-Wave Elastography in Participants with Chronic Hepatitis B: A Prospective Multicenter Study.

Purpose To investigate the diagnostic performance of two-dimensional (2D) shear-wave elastography (SWE) in chronic hepatitis B. Materials and Methods This prospective multicenter study from January 2015 to January 2016 was conducted at 12 hospitals and included 654 participants with chronic hepatitis B who had undergone liver biopsy and 2D SWE examination. Participants were divided into chronic infection and chronic hepatitis groups. The diagnostic performance of 2D SWE was compared with the aspartate amino transferase-to-platelet ratio index (APRI), the Fibrosis-4 index (FIB-4), and transient elastography (TE) by using a DeLong test and was also compared between two subgroups. Dual cutoff values for cirrhosis were determined with multilevel likelihood ratio analysis. Results Overall, 402 participants with chronic hepatitis B were enrolled (154 with chronic infection and 248 with chronic hepatitis). The areas under the receiver operating characteristic curve of 2D SWE (0.87; 95% confidence interval [CI]: 0.83, 0.90) were higher than those of TE (0.80; 95% CI: 0.68, 0.88), APRI (0.70; 95% CI: 0.65, 0.74), and FIB-4 (0.73; 95% CI: 0.69, 0.78) in cirrhosis. The high area under the receiver operating characteristic curve (0.92; 95% CI: 0.87, 0.96) was achieved in the chronic infection group and was significantly higher than that of the chronic hepatitis group (0.84; 95% CI: 0.78, 0.88; P = .017). Dual cutoff values with the likelihood ratios below 0.1 and above 10 (8.4 kPa and 11.0 kPa to rule out and rule in a diagnosis of cirrhosis, respectively) were effectively determined in chronic infection; a total of 81.2% (125 of 154) participants with cirrhosis were definitively diagnosed. Conclusion The performance of two-dimensional (2D) shear-wave elastography (SWE) was higher than that of other noninvasive methods. 2D SWE was most effective in ruling in and ruling out cirrhosis in participants with chronic infection, which may prompt antiviral treatment. © RSNA, 2018 Online supplemental material is available for this article.

Microwave treatment of renal cell carcinoma adjacent to renal sinus.

PURPOSE: To evaluate the efficacy and safety of ultrasound (US)-guided percutaneous microwave ablation (MWA) for renal cell carcinoma (RCC) adjacent to renal sinus. MATERIALS AND METHODS: This retrospective study included 41 patients who underwent US-guided percutaneous MWA of 41 RCCs adjacent to the renal sinus from April 2006 to December 2015. Contrast-enhanced images of US and computed tomography (CT) or magnetic resonance (MR) imaging were performed at pre-ablation and 1day, 1 month, 3 months, and every 6 months after ablation. Initial ablation success (IAS), disease-free survival (DFS), RCC-related survival (RRS), and overall survival (OS) were recorded at the follow-up visits. RESULTS: IAS was achieved in 92.7% (38/41) of the study subjects. The IAS significantly differed between patients with RCCs ≤4cm (100%, 29/29) and RCCs >4cm (75%, 9/12, p=0.021). During the median follow-up of 37.6 (range, 3.0-97.3) months, the estimated 1-, 3-, and 5-year DFS of patients with an initial tumor of ≤4cm were 100%, 89.7%, and 81.5%, respectively. The 1-, 3-, and 5-year RRS were 100%, 93.3%, and 93.3%, respectively. The 1-, 3-, and 5-year OS were 97.1%, 87.8%, and 83.6%, respectively. The multivariate analysis using the Cox proportional hazard model revealed no independent predictor of recurrence among all the variables. There were no MWA-related deaths among the study subjects. One patient developed a retroperitoneal abscess after ablation. CONCLUSION: US-guided percutaneous MWA appears to be a promising method for RCCs adjacent to renal sinus, especially for tumors ≤4cm.

High-resolution Sonographic Measurements of Lower Extremity Bursae in Chinese Healthy Young Men.

BACKGROUND: Lower extremity bursae are very vulnerable to injury during strenuous physical exercises. Understanding the imaging characteristics of normal bursae is essential for early diagnosis of morphological abnormalities. Therefore, we evaluated the normal range of lower extremity bursae in healthy young men using high-resolution ultrasound (HR-US) imaging. METHODS: Bursae in the lower extremities were examined by HR-US in 290 Chinese healthy young men with a median age of 18 years (range, 18-23 years). The bilateral suprapatellar bursa (SPB), deep infrapatellar bursa (DIPB), popliteal bursa (PB), and retrocalcaneal bursa (RCB) were imaged and measured for analysis. RESULTS: The HR-US identification rates of the SPB, DIPB, PB, and RCB were 89.0% (517/580), 55.0% (319/580), 29.4% (171/580), and 49.5% (287/580), respectively. With the assumption that the bursae were normal in 95% of the study participants, the length and width values at the maximal cross-section of the SPB, DIPB, PB, and RCB were ≤18.00 and 6.09 mm, 8.10 and 2.11 mm, 7.67 and 3.93 mm, and 7.82 and 2.04 mm, respectively. CONCLUSIONS: Using HR-US imaging, we were able to analyze lower extremity bursae with high detection rates in healthy young men. The normal ranges of lower extremity bursa dimensions in healthy young men measured by HR-US in this study could be used as reference values for evaluation of bursa abnormalities in the lower extremity.

Ultrasound-guided percutaneous microwave ablation of splenic metastasis: report of four cases and literature review.

PURPOSE: To investigate the feasibility, safety and efficacy of ultrasound guided percutaneous microwave (MW) ablation for small splenic metastasis. MATERIALS AND METHODS: A total of four patients with five pathologically proven splenic metastases (from ovarian, pulmonary, gastric adenocarcinoma and hepatocellular carcinoma, respectively) 1.3 to 2.9 cm in diameter were treated with microwave ablation. A cooled-shaft needle antenna was percutaneously inserted into the tumour under ultrasound guidance. One thermocouple was placed about 0.5 cm away from the tumour to monitor temperature in real time during ablation. Microwaves were emitted at 60 W for 600 s routinely and prolonged as necessary to attain temperatures sufficient to ensure tumour killing. Treatment efficacy was assessed by contrast-enhanced imaging at 1, 3 and 6 months, and every 6 months thereafter. RESULTS: All tumours were completely ablated at a single session and no complications occurred. No local tumour progression was observed at a mean follow up of 22 ± 17.1 months (range 4 to 43 months). The ablation zone was well defined on contrast-enhanced imaging and it gradually shrank with time. One new metastatic lesion was detected in the spleen at 11 months after the ablation and was successfully treated by another MW ablation. The post-ablation survival was mean 22 months. No other complications were observed except for fever and abdominal pain. CONCLUSIONS: Ultrasound-guided percutaneous MW ablation appears to be a safe and effective minimally invasive technique for management of small splenic metastasis in selected patients.

Microwave ablation in the spleen for treatment of secondary hypersplenism: a preliminary study.

OBJECTIVE: The purpose of this study is to evaluate the feasibility, safety, and efficacy of microwave (MW) ablation for the treatment of hypersplenism, via a laparoscopic or percutaneous approach, and its effect on liver function in patients with liver cirrhosis. SUBJECTS AND METHODS: Twenty patients (17 men and three women; mean age, 51.7 ± 11.4 years; age range, 31-68 years) with secondary hypersplenism resulting from liver cirrhosis were treated with MW ablation of splenic parenchyma (13 laparoscopically and seven percutaneously with ultrasound guidance). Splenic volume and ablated volume were calculated according to contrast-enhanced CT scan. Routine blood counts (platelet, leukocyte, and erythrocyte counts) and liver function test results were examined before and after MW ablation. RESULTS: The mean follow-up period was 26.4 ± 11.4 months (range, 6-48 months). After MW ablation, the ablation ratio ranged from 16% to 58% (mean, 30.9% ± 13%). All patients showed an increase in platelet count and leukocyte count after MW ablation, and patients with an ablation ratio greater than 40% showed more sustainable increase of platelet count in the follow-up period. Serum total protein levels significantly increased (p < 0.05). No severe complications occurred. CONCLUSION: MW ablation is a safe and effective technique for the management of hypersplenism in patients with liver cirrhosis. Ablating more than 40% of the splenic parenchyma may yield better long-term results.

915MHz microwave ablation with high output power in in vivo porcine spleens.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of 915 MHz microwave (MW) ablation with high output power in in vivo porcine spleens. MATERIALS AND METHODS: MW ablations were performed in 9 porcine spleens with an internally cooled 915 MHz antenna. Thermocouples were placed at 5, 10, 15, 20 mm away from the antenna to measure temperatures in real-time during MW emission. The energy was applied for 10 min at high output power of 60 W, 70 W or 80 W. Gross specimens were sectioned and measured to determine ablation size. Representative areas were examined by light microscopy and electron microscopy. Coagulation sizes and temperatures were compared among the three power groups. RESULTS: Hematoxylin-eosin staining showed irreversible necrosis in the splenic coagulation area after MW ablation. As the power was increased, long-axis diameter enlarged significantly (p<.05). Short-axis diameter also tended to increase, but there were no statistical difference (p>.05). The coagulation size of long-axis and short-axis diameter with 80 W in vivo spleen ablation was 6.43+/-0.52 and 4.95+/-0.30 cm, respectively. With the increase of output power, maximum temperatures at 5, 10, 15, 20 mm from the antenna were increased accordingly (p<.05). The maximum temperature with 80 W at 5 and 20 mm from the antenna reached 146.17+/-6.65 and 72.38+/-4.23 degrees C respectively. CONCLUSION: With internally cooled antenna and high output power, 915 MHz MW ablation in the spleen could produce irreversible tissue necrosis of clinical significance. MW ablation may be used as a promising minimally invasive method for the treatment of splenic diseases.

Percutaneous microwave ablation or nephrectomy for VX-2 carcinoma in rabbit kidney.

PURPOSE: We compared the effectiveness of percutaneous microwave ablation and radical nephrectomy for implanted VX-2 carcinoma in rabbit kidneys. MATERIALS AND METHODS: VX-2 tumors were surgically implanted into the left lower pole parenchyma of 26 New Zealand White rabbit kidneys. At 12 days after implantation implanted rabbits were randomly assigned to 1 of 3 groups according to therapy type, including percutaneous microwave ablation, nephrectomy and no treatment. The anticancer effect and safety were compared among the groups. Histopathological changes in tumor tissue with time after microwave ablation were evaluated. RESULTS: The survival rate in the percutaneous microwave ablation group was significantly higher than that in the no treatment group and showed no statistically significant difference compared with that in the nephrectomy group. Serum creatinine did not increase after microwave therapy but we noted a statistically significant serum creatinine increase in the nephrectomy group. Histological analysis revealed completely coagulative necrosis of the tumor in 10 of 12 rabbits (83.3%) after microwave ablation. Two rabbits died, including 1 of peritonitis in the nephrectomy group and 1 of intestinal fistula due to heat injury in the percutaneous microwave ablation group. CONCLUSIONS: This study shows that percutaneous microwave ablation can achieve effects similar to those of radical nephrectomy. It caused no significant changes in renal function when treating implanted VX-2 renal tumors. Percutaneous microwave ablation has the potential of being a minimally invasive treatment for small renal tumors.

Comparison of ablation zone between 915- and 2,450-MHz cooled-shaft microwave antenna: results in in vivo porcine livers.

OBJECTIVE: The objective of our study was to compare the ablation zones of two cooled-shaft microwave antennae-one operating at 915 MHz and one operating at 2,450 MHz-in in vivo porcine livers. CONCLUSION: The 915-MHz cooled-shaft microwave antenna can lead to deeper penetration of liver tissue and can yield a significantly larger ablation zone than the 2,450-MHz cooled-shaft antenna in in vivo porcine livers. In light of the result, 915-MHz cooled-shaft microwaves may be more effective for tumor ablation, especially for large tumors.

Ultrasound guided percutaneous microwave ablation for small renal cancer: initial experience.

PURPOSE: We evaluated the feasibility, safety and efficacy of ultrasound guided percutaneous microwave ablation for small renal cell cancers. MATERIALS AND METHODS: A total of 12 patients with a pathologically proven renal cell cancer 1.3 to 3.8 cm in diameter were treated with microwave ablation. A cooled shaft needle antenna was percutaneously inserted into the tumor under ultrasound guidance. One antenna was used for tumors 2 cm or smaller and antennae were used for tumors larger than 2 cm. One thermocouple was placed about 0.5 cm away from the tumor to monitor temperature in real time during ablation. Microwaves were emitted at 50 W for 500 seconds and prolonged as necessary to attain temperatures sufficient to ensure tumor kill. Immediate treatment efficacy was assessed by contrast enhanced ultrasound 1 day after ablation. Short-term efficacy was assessed by contrast enhanced computerized tomography and/or contrast enhanced ultrasound at 1, 3 and 6 months, and every 6 months thereafter. RESULTS: All tumors were completely ablated at a single session and no complications occurred. No residual tumor or recurrence was observed at a median followup of 11 months (range 4 to 20). The ablation zone was well defined on contrast enhanced imaging and it gradually shrank with time. CONCLUSIONS: Ultrasound guided percutaneous microwave ablation appears to be a safe and effective technique for small renal cell cancer in select patients.