Unveiling the diagnostic enigma of D-dimer testing in cancer patients: Current evidence and areas of application.

BACKGROUND: Cancer is a well-known risk factor for venous thromboembolism (VTE). A combined strategy of D-dimer testing and clinical pre-test probability is usually used to exclude VTE. However, its effectiveness is diminished in cancer patients due to reduced specificity, ultimately leading to a decreased clinical utility. This review article seeks to provide a comprehensive summary of how to interpret D-dimer testing in cancer patients. METHODS: In accordance with PRISMA standards, literature pertaining to the diagnostic and prognostic significance of D-dimer testing in cancer patients was carefully chosen from reputable sources such as PubMed and the Cochrane databases. RESULTS: D-dimers have not only a diagnostic value in ruling out VTE but can also serve as an aid for rule-in if their values exceed 10-times the upper limit of normal. This threshold allows a diagnosis of VTE in cancer patients with a positive predictive value of more than 80%. Moreover, elevated D-dimers carry important prognostic information and are associated with VTE reoccurrence. A gradual increase in risk for all-cause death suggests that VTE is also an indicator of biologically more aggressive cancer types and advanced cancer stages. Considering the lack of standardization for D-dimer assays, it is essential for clinicians to carefully consider the variations in assay performance and the specific test characteristics of their institution. CONCLUSIONS: Standardizing D-dimer assays and developing modified pretest probability models specifically for cancer patients, along with adjusted cut-off values for D-dimer testing, could significantly enhance the accuracy and effectiveness of VTE diagnosis in this population.

Postoperative radiological assessment of the mastoid facial canal in cochlear implant patients in correlation with facial nerve stimulation.

OBJECTIVES: To correlate the radiological assessment of the mastoid facial canal in postoperative cochlear implant (CI) cone-beam CT (CBCT) and other possible contributing clinical or implant-related factors with postoperative facial nerve stimulation (FNS) occurrence. METHODS: Two experienced radiologists evaluated retrospectively 215 postoperative post-CI CBCT examinations. The mastoid facial canal diameter, wall thickness, distance between the electrode cable and mastoid facial canal, and facial-chorda tympani angle were assessed. Additionally, the intracochlear position and the insertion angle and depth of electrodes were evaluated. Clinical data were analyzed for postoperative FNS within 1.5-year follow-up, CI type, onset, and causes for hearing loss such as otosclerosis, meningitis, and history of previous ear surgeries. Postoperative FNS was correlated with the measurements and clinical data using logistic regression. RESULTS: Within the study population (mean age: 56 ± 18 years), ten patients presented with FNS. The correlations between FNS and facial canal diameter (p = 0.09), wall thickness (p = 0.27), distance to CI cable (p = 0.44), and angle with chorda tympani (p = 0.75) were statistically non-significant. There were statistical significances for previous history of meningitis/encephalitis (p = 0.001), extracochlear-electrode-contacts (p = 0.002), scala-vestibuli position (p = 0.02), younger patients' age (p = 0.03), lateral-wall-electrode type (p = 0.04), and early/childhood onset hearing loss (p = 0.04). Histories of meningitis/encephalitis and extracochlear-electrode-contacts were included in the first two steps of the multivariate logistic regression. CONCLUSION: The mastoid-facial canal radiological assessment and the positional relationship with the CI electrode provide no predictor of postoperative FNS. Histories of meningitis/encephalitis and extracochlear-electrode-contacts are important risk factors. KEY POINTS: • Post-operative radiological assessment of the mastoid facial canal and the positional relationship with the CI electrode provide no predictor of post-cochlear implant facial nerve stimulation. • Radiological detection of extracochlear electrode contacts and the previous clinical history of meningitis/encephalitis are two important risk factors for postoperative facial nerve stimulation in cochlear implant patients. • The presence of scala vestibuli electrode insertion as well as the lateral wall electrode type, the younger patient's age, and early onset of SNHL can play important role in the prediction of post-cochlear implant facial nerve stimulation.

Feasibility of diffusion-weighted magnetic resonance imaging in evaluation of early therapeutic response after CT-guided microwave ablation of inoperable lung neoplasms.

OBJECTIVE: To determine the early treatment response after microwave ablation (MWA) of inoperable lung neoplasms using the apparent diffusion coefficient (ADC) value calculated 24 h after the ablation. MATERIALS AND METHODS: This retrospective study included 47 patients with 68 lung lesions, who underwent percutaneous MWA from January 2008 to December 2017. Evaluation of the lesions was done using MRI including DWI sequence with ADC value calculation pre-ablation and 24 h post-ablation. DWI-MR was performed with b values (50, 400, 800 mm2/s). The post-ablation follow-up was performed using chest CT and/or MRI within 24 h following the procedure; after 3, 6, 9, and 12 months; and every 6 months onwards to determine the local tumor response. The post-ablation ADC value changes were compared to the end response of the lesions. RESULTS: Forty-seven patients (mean age: 63.8 ± 14.2 years, 25 women) with 68 lesions having a mean tumor size of 1.5 ± 0.9 cm (range: 0.7-5 cm) were evaluated. Sixty-one lesions (89.7%) showed a complete treatment response, and the remaining 7 lesions (10.3%) showed a local progression (residual activity). There was a statistically significant difference regarding the ADC value measured 24 h after the ablation between the responding (1.7 ± 0.3 × 10-3 mm2/s) and non-responding groups (1.4 ± 0.3 × 10-3 mm2/s) with significantly higher values in the responding group (p = 0.001). A suggested ADC cut-off value of 1.42 could be used as a reference point for the post-ablation response prediction (sensitivity: 66.67%, specificity: 84.21%, PPV: 66.7%, and NPV: 84.2%). No significant difference was reported regarding the ADC value performed before the ablation as a factor for the prognosis of treatment response (p = 0.86). CONCLUSION: ADC value assessment following ablation may allow the early prediction of treatment efficacy after MWA of inoperable lung neoplasms. KEY POINTS: • ADC value calculated 24 h post-treatment may allow the early prediction of MWA efficacy as a treatment of pulmonary tumors and can be used in the early immediate post-ablation imaging follow-up. • The pre-treatment ADC value of lung neoplasms is not different between the responding and non-responding tumors.

Long-term outcomes following percutaneous microwave ablation for colorectal cancer liver metastases.

PURPOSE: To evaluate the overall survival (OS), local progression-free survival (PFS) and prognostic factors of patients with colorectal cancer liver metastases (CRLM) undergoing microwave ablation (MWA). METHOD: A total of 132 patients were retrospectively enrolled who had been treated between 2010 and 2018. For the evaluation of survival rates, all patients were divided according to their indications (curative n = 57 and debulking (patients with additional non-target extrahepatic metastases) n = 75). In total, 257 ablations were evaluated for prognostic factors: number of liver metastases, primary tumor origin (PTO), diameter and volume of metastases, duration and energy of ablation. RESULTS: The OS was 32.1 months with 93.2% of patients free from recurrence at 28.3 months (median follow-up time). The one- year and three-year OS were 82.72% and 41.66%, respectively. The OS and recurrence-free survival of the curative group were statistically significantly higher than the debulking group (p < .001). Statistically significant prognostic factors for OS included the location of the primary tumor (p < .038) and the number of metastases (all p < .017). Metastasis diameter and volume and ablation duration and energy had no significant correlation with survival (p > .05). CONCLUSIONS: Satisfactory OS and local tumor PFS can be achieved in patients with CRLM using MWA with the number of metastases and the location of the primary tumor influencing the outcome of patients. The metastasis's size and the duration and energy used for ablation were not of significant prognostic value.

Microwave Ablation (MWA) of Pulmonary Neoplasms: Clinical Performance of High-Frequency MWA With Spatial Energy Control Versus Conventional Low-Frequency MWA.

OBJECTIVE. The objective of our study was to evaluate the clinical performance of a new high-frequency (HF) microwave ablation (MWA) technology with spatial energy control for treatment of lung malignancies in comparison with a conventional low-frequency (LF) MWA technology. MATERIALS AND METHODS. In this retrospective study, 59 consecutive patients (mean age, 58.9 ± 12.6 [SD] years) were treated in 71 sessions using HF spatial-energy-control MWA. Parameters collected were technical success and efficacy, tumor diameter, tumor and ablation volumes, ablation time, output energy, complication rate, 90-day mortality, local tumor progression (LTP), ablative margin size, and ablation zone sphericity. Results were compared with the same parameters retrospectively collected from the last 71 conventional LF-MWA sessions. This group consisted of 56 patients (mean age, 60.3 ± 10.8 years). Statistical comparisons were performed using the Wilcoxon-Mann-Whitney test. RESULTS. Technical success was 98.6% for both technologies; technical efficacy was 97.2% for HF spatial-energy-control MWA and 95.8% for LF-MWA. The 90-day mortality rate was 5.1% (3/59) in the HF spatial-energy-control MWA group and 5.4% (3/56) in the LF-MWA group; for both groups, there were zero intraprocedural deaths. The median ablation time was 8.0 minutes for HF spatial-energy-control MWA and 10.0 minutes for LF-MWA (p < 0.0001). Complications were recorded in 21.1% (15/71) of HF spatial-energy-control MWA sessions and in 31.0% (22/71) of LF-MWA sessions (p = 0.182); of these complications, 4.2% (3/71) were major complications in the HF spatial-energy-control MWA group, and 9.9% (7/71) were major complications in the LF-MWA group. The median deviation from ideal sphericity (1.0) was 0.195 in the HF spatial-energy-control MWA group versus 0.376 in the LF-MWA group (p < 0.0001). Absolute minimal ablative margins per ablation were 7.5 ± 3.6 mm (mean ± SD) in the HF spatial-energy-control MWA group versus 4.2 ± 3.0 mm in the LF-MWA group (p < 0.0001). In the HF spatial-energy-control MWA group, LTP at 12 months was 6.5% (4/62). LTP at 12 months in the LF-MWA group was 12.5% (7/56). Differences in LTP rate (p = 0.137) and time point (p = 0.833) were not significant. CONCLUSION. HF spatial-energy-control MWA technology and conventional LFMWA technology are safe and effective for the treatment of lung malignancies independent of the MWA system used. However, HF spatial-energy-control MWA as an HF and high-energy MWA technique achieves ablation zones that are closer to an ideal sphere and achieves larger ablative margins than LF-MWA (p < 0.0001).

Transarterial chemoembolization in pancreatic adenocarcinoma with liver metastases: MR-based tumor response evaluation, apparent diffusion coefficient (ADC) patterns, and survival rates.

PURPOSE: To retrospectively investigate the effectiveness of triple drug combination transarterial chemoembolization (TACE) on local tumor response and survival in patients with liver metastases from pancreatic cancer. Also, this study will evaluate the variances in response regarding the number of metastases, assess the correlation between tumor response and the changes in the apparent diffusion coefficients (ADC) in diffusion weighted (DW) MRI. MATERIALS AND METHODS: One hundred and twelve patients (58 men and 54 women; mean age 57) with malignant liver metastases from pancreatic adenocarcinoma underwent at least one session of TACE with a chemotherapeutic combination of mitomycin C, cisplatin, and gemcitabine. A size-based evaluation of tumor response (response evaluation criteria in solid tumors (RECIST)) was conducted, along with ADC values, and survival indices as related to treatment pattern. RESULTS: Four weeks following the end of the treatment, 78.26% of patients showed stable disease and 11.59% showed partial response. The median survival time was 19 months and for the stable disease group, 26 months. Low pretreatment ADC values showed no significant correlation to poor response to treatment (r = 0.347,p = 0.146). CONCLUSION: The triple drug TACE technique showed improvements in median survival times in patients with hepatic metastases from pancreatic carcinoma and helped control disease progression, whereas the number of hepatic lesions was not a statistically significant factor in patients' response to TACE. The data suggest that pre-treatment ADC values in DW-MRI have no statistical correlation with tumor response.

Purse-string closure technique reduces the incidence of incisional hernias following the reversal of temporary ileostomy.

PURPOSE: The incidence of incisional hernia (IH) at ileostomy closure site has not been sufficiently evaluated. Temporary loop ileostomy is routinely used in patients after low anterior resection for rectal cancer. The goal of this study was to compare the IH rates of standard suture skin closure and purse-string skin closure techniques. PATIENTS AND METHODS: Patients undergoing ileostomy reversal and follow-up CT scan at the University Hospital Frankfurt between January 2009 and December 2015 were retrospectively analyzed regarding IH and associated risk factors. Patients received either direct stitch skin closure (group DC) or purse-string skin closure (group PS). RESULTS: In total, 111 patients underwent ileostomy reversal in the aforementioned period. In 88 patients, a CT scan was performed 12-24 months after ileostomy reversal for cancer follow-up. Median follow-up was 12 months. Median time interval between ileostoma formation and closure was 12 (± 4 SD) weeks. In 19 of 88 patients (21.5%), an IH was detected. The incidence of IH detected by CT scan was significantly lower in the PS group (n = 7, 12.9%) compared to the DC group (n = 12, 35.2%, p = 0.017). CONCLUSIONS: This retrospective study shows an advantage of the purse-string skin closure technique in ileostomy reversals. The use of this technique for skin closure following ileostomy reversals is recommended to reduce the IH rates. Randomized controlled trials are needed to confirm these findings.

The role of MRI in the early evaluation of lung microwave ablation.

PURPOSE: To retrospectively investigate the role of a contrast enhanced MRI (ceMRI) performed 24 h after a microwave ablation (MWA) of the lung, in predicting local tumour progression (LTP) and detecting complications compared to an unenhanced CT. MATERIAL AND METHODS: Forty-nine patients who underwent MWA of 77 lung metastases between 2008 and 2015 were included. All patients received an unenhanced chest CT and a ceMRI (including T2 and ceT1) 24 h after MWA. The conspicuities of the peripheral rim and the ablated tumour were scored using 1-3 scales and compared between examinations. The safety margin was measured directly (both scores ≥2) and indirectly using a subtraction method. The ability of each imaging modality to predict LTP based on safety margin width was analysed using receiver operating characteristic curves. The MRI ability to detect a pneumothorax was compared to CT. RESULTS: The peripheral rim was best visualised on T2 followed by T1 and CT. The tumour was best visualised on CT, followed by T1 and T2. Direct safety margin measurement was possible on CT, ceT1 and T2 in 68.8%, 64.9% and 27.3% of cases, respectively. Direct CT (AUC = 0.77) and ceT1 (AUC = 0.76) measurements had better diagnostic performance than indirect CT (AUC = 0.72), ceT1 (AUC = 0.70) and T2 (AUC = 0.69) measurements. The MRI sensitivity and specificity for pneumothorax were 60.8% and 87.0%, respectively. Only one pneumothorax >1 cm was missed. CONCLUSIONS: A ceMRI performed 24 h after MWA of lung tumours has a similar ability to predict LTP and detect important complications as a CT has.

Evaluation of microwave ablation of liver malignancy with enabled constant spatial energy control to achieve a predictable spherical ablation zone.

OBJECTIVES: To evaluate the clinical performance of a new microwave ablation (MWA) system with enabled constant spatial energy control (ECSEC) to achieve spherical ablation zones in the treatment of liver malignancies. MATERIALS AND METHODS: In this retrospective study, 56 hepatic tumours in 48 patients (23 men, 25 women; mean age: 59.6 years) were treated using a new high-frequency MWA-system with ECSEC. Parameters evaluated were technical success, technical efficacy, tumour diameter, tumour and ablation volume, complication rate, 90-day mortality, local tumour progression (LTP) at the 12-month follow-up, ablative margin and ablation zone sphericity. These parameters were compared using the Kruskal-Wallis test with the same parameters collected retrospectively from cohorts of patients treated with conventional high-frequency (HF) MWA (n = 20) or low-frequency (LF) MWA (n = 20). RESULTS: Technical success was achieved in all interventions. The technical efficacy was 100% (ECSEC) vs. 100% (LF-MWA) vs. 95% (HF-MWA). There were no intra-procedural deaths or major complications. Minor complications occurred in 3.57% (2/56), 0% (0/20) and 0% (0/20) of the patients, respectively. The one-year mortality rate was 16.1% (9/56), 15% (3/20) and 10% (2/20), respectively. The LTP was 3.57% (2/56), 5% (1/20) and 5% (1/20), respectively. The median deviation from ideal sphericity (1.0) was 0.135 (ECSEC) vs. 0.344 (LF-MWA) vs. 0.314 (HF-MWA) (p < 0.001). The absolute minimal ablative margin was 8.1 vs. 2.3 vs. 3.1 mm (p < 0.001). CONCLUSIONS: Microwave ablation of liver malignancies is a safe and efficient treatment independent of the system used. Hepatic MWA with ECSEC achieves significantly more spherical ablation zones and higher minimal ablative margins.

Microwave ablation of pancreatic tumors.

OBJECTIVES: To evaluate the clinical performance of percutaneous microwave ablation (MWA) for treatment of locally-advanced-pancreatic-cancer (LAPC). MATERIAL AND METHODS: Twenty-two MWA sessions (August 2015-March 2017) in 20 patients with primary pancreatic cancer (13 men, 7 women, mean-age: 59.9 ± 8.6 years, range: 46-73 years), who had given informed consent, were retrospectively evaluated. All procedures were performed percutaneously under CT-guidance using the same high-frequency (2.45-GHz) MWA device. Tumor location and diameter, ablation diameter and volume, roundness, duration, technical success and efficacy, output energy, complications, and local tumor progression defined as a tumor focus connected to the edge of a previously technically efficient ablation zone were collected. RESULTS: Seventeen pancreatic malignant tumors (77.3%) were located in the pancreatic head and five (22.7%) in the pancreatic tail. Initial Mean Tumor Diameter was 30 ± 6 mm. Technical success and efficacy were idem (100%). No major complications occurred. Two patients (9.1%) showed minor complications of severe local pain related to MWA. Post-ablation diameter was on average 34.4 ± 5.8 mm. Mean ablation volume was 7.8 ± 3.8 cm³. The mean transverse roundness index was 0.74 ± 0.14. Mean ablation time was 2.6 ± 0.96 min. The mean applied energy per treatment was 9627 ± 3953 J. Local tumor progression was documented in one case (10%) of the 10/22 available three-month follow-up imaging studies. CONCLUSION: High-frequency (2.45 GHz) microwave ablation (MWA) for treatment of unresectable and non-metastatic locally-advanced-pancreatic-cancer (LAPC) shows promising results regarding feasibility and safety of percutaneous approach after short-term follow-up and should be further evaluated.

Ablation therapy of non-colorectal cancer lung metastases: retrospective analysis of tumour response post-laser-induced interstitial thermotherapy (LITT), radiofrequency ablation (RFA) and microwave ablation (MWA).

PURPOSE: To retrospectively compare the local tumour response and survival rates in patients with non-colorectal cancer lung metastases post-ablation therapy using laser-induced thermotherapy (LITT), radiofrequency ablation (RFA) and microwave ablation (MWA). MATERIAL AND METHODS: Retrospective analysis of 175 computed tomography (CT)-guided ablation sessions performed on 109 patients (43 males and 66 females, mean age: 56.6 years). Seventeen patients with 22 lesions underwent LITT treatment (tumour size: 1.2-4.8 cm), 29 patients with 49 lesions underwent RFA (tumour size: 0.8-4.5 cm) and 63 patients with 104 lesions underwent MWA treatment (tumour size: 0.6-5 cm). CT scans were performed 24-h post-therapy and on follow-up at 3, 6, 12, 18 and 24 months. RESULTS: The overall-survival rates at 1-, 2-, 3- and 4-year were 93.8, 56.3, 50.0 and 31.3% for patients treated with LITT; 81.5, 50.0, 45.5 and 24.2% for patients treated with RFA and 97.6, 79.9, 62.3 and 45.4% for patients treated with MWA, respectively. The mean survival time was 34.14 months for MWA, 34.79 months for RFA and 35.32 months for LITT. In paired comparison, a significant difference could be detected between MWA versus RFA (p = 0.032). The progression-free survival showed a median of 23.49 ± 0.62 months for MWA,19.88 ± 2.17 months for LITT and 16.66 ± 0.66 months for RFA (p = 0.048). The lowest recurrence rate was detected in lesions ablated with MWA (7.7%; 8 of 104 lesions) followed by RFA (20.4%; 10 of 49 lesions) and LITT (27.3%; 6 of 22 lesions) p value of 0.012. Pneumothorax was detected in 22.16% of MWA ablations, 22.73% of LITT ablations and 14.23% of RFA ablations. CONCLUSION: LITT, RFA and MWA may provide an effective therapeutic option for non-colorectal cancer lung metastases with an advantage for MWA regarding local tumour control and progression-free survival rate.

Intraprocedural blood volume measurement using C-arm CT as a predictor for treatment response of malignant liver tumours undergoing repetitive transarterial chemoembolization (TACE).

PURPOSE: To evaluate feasibility of measuring parenchymal blood volume (PBV) of malignant hepatic tumours using C-arm CT, test the changes in PBV following repeated transarterial chemoembolization (TACE) and correlate these changes with the change in tumour size in MRI. METHODS: 111 patients with liver malignancy were included. Patients underwent MRI and TACE in a 4- to 6-week interval. During intervention C-arm CT was performed. Images were post-processed to generate PBV maps. Blood volume data in C-arm CT and change in size in MRI were evaluated. The correlation between PBV and size was tested using Spearman rank test. RESULTS: Pre-interventional PBV maps showed a mean blood volume of 84.5 ml/1000 ml ± 62.0, follow-up PBV maps after multiple TACE demonstrated 61.1 ml/1000 ml ± 57.5. The change in PBV was statistically significant (p = 0.02). Patients with initial tumour blood volume >100 ml/1000 ml dropped 7.1% in size and 47.2% in blood volume; 50-100 ml/1000 ml dropped 4.6% in size and 25.7% in blood volume; and <50 ml/1000 ml decreased 2.8% in size and increased 82.2% in blood volume. CONCLUSION: PBV measurement of malignant liver tumours using C-arm CT is feasible. Following TACE PBV decreased significantly. Patients with low initial PBV show low local response rates and further increase in blood volume, whereas high initial tumour PBV showed better response to TACE. KEY POINTS: Parenchymal blood volume assessment of malignant hepatic lesions using C-arm CT is feasible. The parenchymal blood volume is reduced significantly following transarterial chemoembolization. Parenchymal blood volume can monitor the response of tumours after transarterial chemoembolization. Although not significant, high initial parenchymal blood volume yields better response to TACE.

Long-Term Changes in Aortic Length after Thoracic Endovascular Aortic Repair.

PURPOSE: To study long-term changes to the thoracic aorta following thoracic endovascular aortic repair (TEVAR) for treatment of different aortic pathologic conditions. MATERIALS AND METHODS: This retrospective study included 53 consecutive patients (mean age, 58.8 y ± 14; 13 female and 40 male) in whom TEVAR was performed between October 2002 and May 2010. The mean duration of follow-up was 21.1 months (range, 0.5-96 mo). Statistical analysis was performed with the Friedman test and Conover-Iman test. RESULTS: Nineteen patients with aortic aneurysm (group 1), 25 patients with type B dissection (group 2), and 9 patients with other pathologic conditions (group 3) were treated with TEVAR. The mean overall aortic lengths (from the origin of the left subclavian artery to the origin of the celiac trunk) before TEVAR were 271.4 mm, 268.6 mm, and 233.6 mm in groups 1, 2, and 3, respectively. At 12-month follow-up, the lengths were 282.8 mm, 294.4 mm, and 237.5 mm in groups 1, 2, and 3, respectively. The changes in aortic lengths following TEVAR were statistically significant (P < .001). A second intervention was required in 14 patients, and 6 patients died during follow-up. CONCLUSIONS: A significant change in the overall aortic length was observed following TEVAR. The changes in aortic length reached statistical significance after 12 months.

Thermal Ablation of Colorectal Lung Metastases: Retrospective Comparison Among Laser-Induced Thermotherapy, Radiofrequency Ablation, and Microwave Ablation.

OBJECTIVE: The purpose of this study is to retrospectively evaluate local tumor control, time to tumor progression, and survival rates among patients with lung metastatic colorectal cancer who have undergone ablation therapy performed using laser-induced thermotherapy (LITT), radiofrequency ablation (RFA), or microwave ablation (MWA). MATERIALS AND METHODS: Data for this retrospective study were collected from 231 CT-guided ablation sessions performed for 109 patients (71 men and 38 women; mean [± SD] age, 68.6 ± 11.2 years; range, 34-94 years) from May 2000 to May 2014. Twenty-one patients underwent LITT (31 ablations), 41 patients underwent RFA (75 ablations), and 47 patients underwent MWA (125 ablations). CT scans were acquired 24 hours after each therapy session and at follow-up visits occurring at 3, 6, 12, 18, and 24 months after ablation. Survival rates were calculated from the time of the first ablation session, with the use of Kaplan-Meier and log-rank tests. Changes in the volume of the ablated lesions were measured using the Kruskal-Wallis method. RESULTS: Local tumor control was achieved in 17 of 25 lesions (68.0%) treated with LITT, 45 of 65 lesions (69.2%) treated with RFA, and 91 of 103 lesions (88.3%) treated with MWA. Statistically significant differences were noted when MWA was compared with LITT at 18 months after ablation (p = 0.01) and when MWA was compared with RFA at 6 months (p = 0.004) and 18 months (p = 0.01) after ablation. The overall median time to local tumor progression was 7.6 months. The median time to local tumor progression was 10.4 months for lesions treated with LITT, 7.2 months for lesions treated with RFA, and 7.5 months for lesions treated with MWA, with no statistically significant difference noted. New pulmonary metastases developed in 47.6% of patients treated with LITT, in 51.2% of patients treated with RFA, and in 53.2% of patients treated with MWA. According to the Kaplan-Meier test, median survival was 22.1 months for patients who underwent LITT, 24.2 months for those receiving RFA, and 32.8 months for those who underwent MWA. The overall survival rate at 1, 2, and 4 years was 95.2%, 47.6%, and 23.8%, respectively, for patients treated with LITT; 76.9%, 50.8%, and 8.0%, respectively, for patients treated with RFA; and 82.7%, 67.5%, and 16.6%, respectively, for patients treated with MWA. The log-rank test revealed no statistically significant difference among LITT, RFA, and MWA. The progression-free survival rate at 1, 2, 3, and 4 years was 96.8%, 52.7%, 24.0%, and 19.1%, respectively, for patients who underwent LITT; 77.3%, 50.2%, 30.8%, and 16.4%, respectively, for patients who underwent RFA; and 54.6%, 29.1%, 10.0%, and 1.0%, respectively, for patients who underwent MWA, with no statistically significant difference noted among the three ablation methods. CONCLUSION: LITT, RFA, and MWA can be used as therapeutic options for lung metastases resulting from colorectal cancer. Statistically significant differences in local tumor control revealed a potential advantage in using MWA. No differences in time to tumor progression or survival rates were detected when the three different ablation methods were compared.

Real-time qualitative MR monitoring of microwave ablation in ex vivo livers.

PURPOSE: Computed tomography (CT) and ultrasound-guided microwave ablations (MWA) are part of the established treatment of liver tumours. In spite of its potential advantages, magnetic resonance (MR) monitoring of MWA did not enter clinical practice because of the lack of compatible devices. The purpose of the current study was to prove the feasibility of real-time qualitative MR monitoring using a new MR-compatible MWA device. MATERIAL AND METHODS: We performed 27 MWA experiments with different durations (5, 10 and 15 min) on an ex vivo bovine liver model using a MR-compatible MWA device. We compared the diameters of the ablation zone as depicted on three T1-based sequences to those of the macroscopic specimen. The volume and the sphericity index of the macroscopic ablation area were calculated in order to characterise the device. Ablation pattern and artefacts on the three sequences were also taken into account. RESULTS: We obtained high-quality real-time images using all three sequences. The diameters as depicted on the MR sequences slightly overestimated the macroscopic ablation area but correlated significantly in all cases (p < 0.05). VIBE provided the best correlation for both short-axis diameter (r = 0.96) and long-axis diameter (r = 0.87), whereas starVIBE (r = 0.85; r = 0.72) and FLASH (r = 0.75; r = 0.84) correlated slightly less. Significantly more severe noise artefacts were observed on starVIBE compared to FLASH and VIBE sequences (p < 0.0001). CONCLUSION: The current ex vivo liver model experiment suggests that real-time qualitative MR monitoring of MWA is feasible. Further research using in vivo and human models are recommended.

High-frequency versus low-frequency microwave ablation in malignant liver tumours: evaluation of local tumour control and survival.

PURPOSE: To compare local tumour control and survival rates in patients with liver metastases treated with microwave ablation (MWA), using either a low-frequency (LF) (915 MHz) or high-frequency (HF) system (2.45 GHz). MATERIALS AND METHODS: The retrospective study included 221 patients (mean age: 61.7 years) with 356 malignant hepatic lesions. Ninety-four patients with 133 lesions underwent LF-MWA between September 2008 and February 2011, while 127 patients with 223 lesions were treated with HF-MWA between March 2011 and July 2013. MRI was performed after 24 h from each procedure and at 3, 6, 9, 12, 18 and 24 months post-ablation. Both groups were compared with the Fisher's exact test. Survival rates were calculated using the Kaplan-Meier test. RESULTS: The mean initial ablation volume of LF-MWA was nearly half of HF-MWA (19.1 mL vs. 39.9 mL). The difference in volume between both systems was significant (p < .0001). With LF-MWA, 39/133 lesions (29.32%) progressed at follow-up while the number of lesions which progressed with HF-MWA was 10/223 (4.5%). The mean time to progression was 5.03 and 5.31 months for the lesions treated with LF-MWA and HF-MWA, respectively. The difference between both systems was significant (p = .00059). The 1-, 2- and 4-year overall survival rates for curative indication were 98.9%, 95.7% and 82.9% for LF-MWA, respectively, and were 100%, 97.6% and 92.9% for HF-MWA, respectively. The difference in survival rates was not significant (p > .05). CONCLUSION: Both LF- and HF-MWA systems are effective treatment options for oligonodular liver malignant lesions, but significantly higher ablation volumes, longer time to progression and lower progression rates were observed in HF-MWA.

Improved visual delineation of the intimal flap in Stanford type A and B dissections at 3rd generation dual-source high-pitch CT angiography.

OBJECTIVE: Evaluation of the intimal flap visibility comparing 2nd and 3rd generation dual-source high-pitch CT. METHODS: Twenty-five consecutive patients with aortic dissection underwent CT angiography on a second and third generation dual-source CT scanner using prospective ECG-gated high-pitch dual-source CT acquisition mode. Contrast material, saline flush and flow rate were kept equal for optimum comparability. The visibility of the intimal flap as well as the delineation of the different vascular structures was evaluated. RESULTS: In 3rd generation dual-source high-pitch CT we could show a significant improvement of intimal flap visibility in aortic dissection. Especially, the far end of the dissection membrane could be better evaluated in 3rd generation high-pitch CT, reaching statistical significance (P < 0.01). CONCLUSION: 3rd Generation high-pitch CT angiography shows a better delineation of the aortic intimal flap in a small patient cohort, especially in the far ends of the dissection membrane. This might be due to higher tube power in this CT generation. However, to generalise these findings larger trials are needed.

First Clinical Evaluation of High-Pitch Dual-Source Computed Tomographic Angiography Comparing Automated Tube Potential Selection With Automated Tube Current Modulation.

OBJECTIVE: To investigate and compare the use of automated tube potential selection (ATPS) with automated tube current modulation (ATCM) in high-pitch dual-source computed tomographic angiography (CTA) for imaging the whole aorta without electrocardiogram synchronization. METHODS: Two groups of 60 patients underwent CTA on a dual-source computed tomographic device in high-pitch mode: ATCM (with 100-kV fixed tube potential) was used in group 1 and ATPS (with the same image quality options) in group 2. For the evaluation of radiation exposure, CT dose index and dose-length product were analyzed. Contrast and image quality were assessed by 2 independent observers. RESULTS: The ATPS group received a higher radiation dose than the ATCM group (P < 0.001) because in 80% of patients, the software switched to use of a 120-kV tube potential. In all cases, images of the aorta were of sufficient quality. CONCLUSIONS: High-pitch dual-source CTA of the aorta using ATPS is feasible in clinical routine, but is associated with higher radiation exposure than the ATCM protocol. This finding contradicts previously evaluations of ATPS based on single-source techniques.

Ablation therapy of hepatocellular carcinoma: a comparative study between radiofrequency and microwave ablation.

PURPOSE: The aim of the study is to retrospectively evaluate and compare the therapeutic response of Radiofrequency (RF) and Microwave (MW) ablation therapy of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: 53 consecutive patients (42 males, 11 females; mean age 59 years, range: 40-68, SD: 4.2) underwent CT-guided percutaneous RF and MW ablation of 68 HCC liver lesions. The morphologic tumor response (number, location and size) was evaluated by magnetic resonance imaging. The follow-up protocol was 24 h post-ablation then within 3 monthly intervals post-ablation in the first year and 6 monthly intervals thereafter. RESULTS: Complete therapeutic response was noted in 84.4% (27/32) of lesions treated with RFA and in 88.9% (32/36) of lesions treated with MW ablation (P = 0.6). Complete response was achieved in all lesions ≤2.0 cm in diameter in both groups. There was no significant difference in rates of residual foci of HCC lesions between RF and MW ablation groups (P = 0.15, Log-rank test). Recurrence rate for 3, 6, 9, and 12 months in patients with HCC who underwent RF ablation compared with MW ablation were 6.3%, 3.1%, 3.1% versus 0%, 5.6%, 2.8%, and 2.8%. Progression-Free Survival rates for treated patients with RF ablation of 1, 2, and 3 years were 96.9%, 93.8%, and 90.6% and treated with MW ablation therapy were 97.2%, 94.5%, and 91.7, respectively (P = 0.98). CONCLUSION: In conclusion, RF and MW ablation therapy showed no significant difference in the treatment of HCC regarding the complete response, rates of residual foci of untreated disease, and recurrence rate.

CT chest and gantry rotation time: does the rotation time influence image quality?

BACKGROUND: Computed tomography (CT) gantry rotation time is one factor influencing image quality. Until now, there has been no report investigating the influence of gantry rotation time on chest CT image quality. PURPOSE: To investigate the influence of faster gantry rotation time on image quality and subjective and objective image parameters in chest CT imaging. MATERIAL AND METHODS: Chest CT scans from 160 patients were examined in this study. All scans were performed using a single-source mode (collimation, 128 × 0.6 mm; pitch, 1.2) on a dual-source CT scanner. Only gantry rotation time was modified, while other CT parameters were kept stable for each scan (120 kV/110 reference mAs). Patients were divided into four groups based on rotation time: group 1, 1 s/ rotation (rot); group 2, 0.5 s/rot; group 3, 0.33 s/rot; group 4, 0.28 s/rot. Two blinded radiologists subjectively compared CT image quality, noise, and artifacts, as well as radiation exposure, from all groups. For objective comparison, all image datasets were analyzed by a radiologist with 5 years of experience concerning objective measurements as well as signal-to-noise ratio (SNR). RESULTS: We found that faster gantry rotation times (0.28 s/rot and 0.33 s/rot) resulted in more streak artifacts, image noise, and decreased image quality. However, there was no significant difference in radiation exposure between faster and slower rotation times (P > 0.7). CONCLUSION: Faster CT gantry rotation reduces scan time and motion artifacts. However, accelerating rotation time increases image noise and streak artifacts. Therefore, a slower CT gantry rotation speed is still recommended for higher image quality in some cases.