Occurrence of spontaneous fistulas detected by contrast filling during computed tomography-guided percutaneous drainage placement of splenic and perisplenic fluid collections.

BACKGROUND: Fistulas are serious complications of splenic and perisplenic fluid accumulations, which are often difficult to detect by routine imaging methods. PURPOSE: To evaluate the occurrence of spontaneous fistulas detectable during computed tomography-guided percutaneous drainage placement (CTGDP) with contrast filling of splenic or perisplenic fluid collections and to assess characteristics in comparison with perihepatic or peripancreatic fluid accumulations, also being treated with CTGDP. MATERIAL AND METHODS: In 127 CTGDP-procedures, pre-interventional CTs conducted with intravenous contrast agent were compared to post-interventional CTs including contrast filling of the drain to identify spontaneous fistulas. Patient and case characteristics were evaluated, and therapeutic consequences of fistula identification were analyzed. RESULTS: A total of 43 perisplenic, 40 peripancreatic, and 44 perihepatic drains were evaluated; 13 (30.2%) perisplenic, 7 (17.5%) peripancreatic, and 10 (22.7%) perihepatic fistulas were observed. Concerning the frequency of fistulas, no significant difference was found between the patient groups (P = 0.39). All fistulas were solely proven in CT scans including contrast filling of the drain. Seven fistulas (23.3%) required additional interventions. Perihepatic drains were significantly more often associated with recent surgery (P < 0.001). The mean size of peripancreatic drains was significantly greater (11.8 ± 3.9 F; P < 0.001) than in perihepatic or perisplenic fluid collections. CONCLUSION: Spontaneous fistulas detected during CTGDP of splenic or perisplenic fluid collections are common. Post-interventional contrast filling of the drain drastically improves the detection rate of perisplenic, peripancreatic and perihepatic fistulas simultaneously initiating appropriate follow-up interventions.

Necessity of Immediate MRI Imaging in the Acute Care of Severely Injured Patients.

Background and Objectives: The standard diagnostic procedure for a patient with a suspected polytrauma injury is computed tomography (CT). In individual cases, however, extended acute imaging using magnetic resonance imaging (MRI) can provide valuable and therapy-relevant information. The aim of our cohort study was to find such cases and to describe their characteristics in order to be able to give possible recommendations for MRI application in acute trauma situations. Materials and Methods: In the study period from 2015-2019, an evaluation of the imaging performed on polytrauma patients was carried out. The specific diagnostic and therapeutic criteria of the MRI group were further defined. Results: In total, 580 patients with an ISS ≥16 (injury severity score) were included in the study. Of these 580 patients, 568 patients received a CT scan and 12 patients an MRI scan as part of the initial diagnostic. Altogether, 66.67% of the MRIs took place outside of regular service hours. The main findings for MRI indications were neurological abnormalities with a focus on myelon injuries. Further MRI examinations were performed to rule out vascular injuries. All in all, 58.3% of the MRIs performed resulted in modified therapeutic strategies afterward. Conclusions: MRI in the context of acute diagnostic of a severely injured patient will likely remain reserved for special indications in the future. However, maximum care hospitals with a high flow of severely injured patients should provide 24/7 MR imaging to ensure the best possible care, especially in neurological and blunt vascular injuries.

Magnetic Resonance Image Findings and Potential Anatomic Risk Factors for Chodromalacia in Children and Adolescents Suffering from Non-Overload Atraumatic Knee Pain in the Ambulant Setting.

PURPOSE: To evaluate magnetic resonance image (MRI) findings in children and adolescents suffering from knee pain without traumatic or physical overload history and to identify potential anatomic risk factors. MATERIAL AND METHODS: A total of 507 MRIs of 6- to 20-year-old patients (251 males; 256 females) were evaluated with regard to detectable pathologies of the knee. The results were compared to a control group without pain (n = 73; 34 males; 39 females). A binary logistic regression model and t-tests for paired and unpaired samples were used to identify possible risk factors and significant anatomic differences of the study population. RESULTS: In 348 patients (68.6%), at least one pathology was detected. The most commonly detected finding was chondromalacia of the patellofemoral (PF) joint (n = 205; 40.4%). Chondral lesions of the PF joint occurred significantly more often in knee pain patients than in the control group (40% vs. 11.0%; p = 0.001), especially in cases of a patella tilt angle > 5° (p ≤ 0.001), a bony sulcus angle > 150° (p = 0.002), a cartilaginous sulcus angle > 150° (p = 0.012), a lateral trochlear inclination < 11° (p ≤ 0.001), a lateralised patella (p = 0.023) and a Wiberg type II or III patella shape (p = 0.019). Moreover, a larger patella tilt angle (p = 0.021), a greater bony sulcus angle (p = 0.042), a larger cartilaginous sulcus angle (p = 0.038) and a lower value of the lateral trochlear inclination (p = 0.014) were detected in knee pain patients compared to the reference group. CONCLUSION: Chondromalacia of the PF joint is frequently observed in children and adolescents suffering from non-overload atraumatic knee pain, whereby a patella tilt angle > 5°, a bony sulcus angle > 150°, a cartilaginous sulcus angle > 150°, a lateral trochlear inclination < 11°, a lateralised patella and a Wiberg type II or III patella shape seem to represent anatomic risk factors.

The chronic pancreatitis (CP) Type Cambridge 2 as a cause of unclear upper abdominal pain: a radiologically underestimated diagnosis. / Die chronische Pankreatitis (CP) Typ Cambridge 2 als Ursache unklarer Oberbauchschmerzen: eine radiologisch unterschätzte Diagnose.

The time interval from symptom onset to the diagnosis of chronic pancreatitis (CP) remains disproportionately long today due to nonspecific symptoms and the absence of a definitive laboratory marker. Nevertheless, mortality is increased by 3.6 times compared to the general population. Additionally, the risk of developing pancreatic carcinoma is 16 times higher in the presence of CP. According to the current S3 guideline, the morphological staging of CP should be based on the Cambridge Classification for CT/MRCP. Most radiologists morphologically associate CP with Cambridge Stage 4, which is characterized by classic calcifications. The subtle morphologies of earlier Cambridge Stages are often unrecognized, leading to delayed diagnosis. The aim of this study was to diagnose CP at Cambridge Stage 2 as the cause of unexplained upper abdominal discomfort.A retrospective analysis was conducted on 266 patients with unexplained upper abdominal pain who underwent outpatient MRI with MRCP between January 1, 2021, and October 1, 2023. The criteria for Cambridge Stage 2 were evaluated: pancreatic duct in the corpus measuring between 2 and 4 mm, pancreatic hypertrophy, cystic changes < 10 mm, irregularities in the duct, or > 3 pathological side branches. Patients with known tumors or other leading diagnoses, which explained the discomfort, were excluded.25 patients (15 female, 10 male) met the criteria for CP Stage 2 (9%). Ductal dilation between 2 and 4 mm was visible in 21 cases. Pancreatic hypertrophy was observed in six cases. Cystic changes < 10 mm were identified in three cases. Irregularities in the duct ("wavy duct") were diagnosed in 19 patients. Dilation of > 3 side branches was recognized in 17 cases. Lipase levels were additionally determined, with 13 patients showing pathologically elevated levels (> 60 U/l).CP at Cambridge Stage 2 is an important and underestimated diagnosis in patients with unexplained upper abdominal pain in the outpatient setting. Radiologists should pay attention not only to common signs like calcifications, large cysts, or duct strictures but also to subtle changes such as duct irregularities ("wavy duct configuration") and pathologically dilated side branches, which could lead to a significantly earlier diagnosis of CP. Lipase determination may be an additional indication of chronic pancreatitis in this context. · Early-stage Cambridge 2 CP is an important and underestimated diagnosis in patients with unexplained upper abdominal pain in the outpatient setting.. · Radiologists should pay attention to subtle signs of early CP.. · Additional information about lipase levels can be helpful in the diagnostic process..

Detection of Incomplete Irreversible Electroporation (IRE) and Microwave Ablation (MWA) of Hepatocellular Carcinoma (HCC) Using Iodine Quantification in Dual Energy Computed Tomography (DECT).

Early detection of local tumor progression (LTP) after irreversible electroporation (IRE) and microwave ablation (MWA) of hepatocellular carcinoma (HCC) remains challenging. The goal of this study was to identify cases with insufficient ablation and prevent HCC recurrencies by measuring iodine uptake using dual-energy computed tomography (DECT). In 54 HCC-patients, the volumetric iodine concentration (VIC) of the central and peripheral ablation area was evaluated by DECT within 24 h after IRE or MWA. Follow-up was performed with CT and/or MRI at 6 weeks, 3, 6, 9, and 12 months, respectively. In both groups, LTP was solely detected in the peripheral area (IRE: n = 4; MWA: n = 4) and LTP patients showed significantly higher VIC values in the peripheral zone than patients without LTP (IRE: * p = 0.0005; MWA: * p = 0.000). In IRE-LTP patients, no significant difference between the VIC values of non-ablated liver tissue and the peripheral zone was detected (p = 0.155). The peripheral zones of IRE patients without LTP (* p = 0.000) and MWA patients, irrespective of the presence of LTP (LTP: * p = 0.005; without LTP: * p = 0.000), showed significantly lower VIC values than non-ablated liver parenchyma. Higher BCLC tumor stages were indicative for LTP (* p = 0.008). The study suggests that elevated iodine uptake in the peripheral ablation zone could help identify LTP after IRE and MWA of HCC.

Erroneous placement of central venous catheters in subclavian artery: Retrieval and successful hemostasis with a femoral closure device.

BACKGROUND: Retrospective evaluation of the safety and efficacy of the retrieval of misplaced central venous catheters (CVCs) in subclavian arteries using the femoral closure device Angio-Seal™. METHODS: The clinical data of five patients (female, n = 2; mean age, 55.0 years ± 11.9) in whom a misplaced CVC within a subclavian artery was removed followed by closure of the vessel entry site with 8-French (F) Angio-Seal™ was analyzed. RESULTS: In 4/5 patients (80%; CVC diameter, 7-8F) the procedure was technically successful without complications. In 1/5 patients (20%; CVC diameter, 11.5F) the procedure failed and an additional covered stent was placed for successful closure of the vessel entry site. There were no complications associated with the Angio-Seal™ or stent implantation during follow-up. CONCLUSION: Retrieval of a misplaced CVC within a subclavian artery using the percutaneous closure device Angio-Seal™ is quite safe and effective; however, caution is required if there is a mismatch in the diameter of the Angio-Seal™ and CVC. In the case of procedure failure, successful closure of the vessel entry site can be achieved by covered stent placement.

Percutaneous Aspiration Thrombectomy for Arterial Thromboembolic Occlusion Following Percutaneous Transluminal Angioplasty: Technical Success Rates and Clinical Outcomes.

PURPOSE: We aimed to analyze the technical success rate of manual percutaneous aspiration thrombectomy (PAT) in patients with peripheral arterial thromboembolism as a complication of infrainguinal percutaneous transluminal angioplasty (PTA) and we sought to evaluate the 30-day postintervention clinical outcome. MATERIALS AND METHODS: We retrospectively identified 29 patients (men/women, 18/11; mean age, 74 years) who underwent infrainguinal PAT to treat thromboembolic complications of infrainguinal PTA. Primary and secondary technical successes were defined as residual stenosis of < 50 % of the vessel diameter after PAT alone and PAT with additional PTA, respectively. Clinical outcome parameters (e. g., amputation, need for further intervention) were evaluated during the first 30 days after intervention. RESULTS: The primary and secondary technical success rates were 58.6 % (17/29) and 79.3 % (23/29), respectively. Clinical outcome data were available for 93.1 % (27/29) of patients. No further intervention was required within 30 days in 81.5 % (22/27) of patients. Four patients underwent minor amputations owing to preexisting ulcerations (Rutherford Category 5), and no patients underwent major amputations (Rutherford Category 6). Revascularization of the previously treated vessel segment with PTA was necessary on the first postintervention day in one patient. CONCLUSION: Manual PAT, with PTA if needed, has a good technical success rate and satisfactory early clinical outcome in patients with iatrogenic thromboembolic complications after infrainguinal PTA. KEY POINTS: · Manual PAT is a possible first-choice treatment of infrainguinal PTA-induced acute thromboembolism.. · Performing additional PTA increases the success rate of manual PAT.. · Unlike catheter-directed intraarterial lysis, manual PAT carries no risk of bleeding.. CITATION FORMAT: · Schicho A, Bäumler W, Verloh N et al. Percutaneous Aspiration Thrombectomy for Arterial Thromboembolic Occlusion Following Percutaneous Transluminal Angioplasty: Technical Success Rates and Clinical Outcomes. Fortschr Röntgenstr 2022; 194: 291 - 295.

Early Detection of Local Tumor Progression after Irreversible Electroporation (IRE) of a Hepatocellular Carcinoma Using Gd-EOB-DTPA-Based MR Imaging at 3T.

This single-center retrospective study was conducted to improve the early detection of local tumor progression (LTP) after irreversible electroporation (IRE) of a hepatocellular carcinoma (HCC) using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-based 3T MR imaging and to identify helpful signal characteristics by comparing 23 patients with and 60 patients without LTP. To identify the differences in the sensitivity of MRI sequences, the specificity, positive prediction value, negative prediction value (NPV) and diagnostic odds ratio were calculated. A chi-squared test, two-tailed student's t-test and binary logistic regression model were used to detect distinct patient characteristics and variables for the prediction of LTP. LTP was mostly detected in the peripheral ablation zone (82.6%) within the first six months (87.0%). The central LTP ablation area presented more hypointensities in T1 p.v. (sensitivity: 95.0%; NPV: 90.0%) and in T1 d.p. (sensitivity: 100.0%; NPV: 100.0) while its peripheral part showed more hyperintensities in T2 BLADE (sensitivity: 95.5%; NPV: 80.0%) and in diffusion sequences (sensitivity: 90.0%). Liver cirrhosis seems to be an unfavorable prognosticator for LTP (p = 0.039). In conclusion, LTP mostly occurs in the peripheral ablation zone within six months after IRE. Despite often exhibiting atypical Gd-EOB-DTPA MR signal characteristics, T2 BLADE and diffusion sequences were helpful for their detection in the peripheral zone while T1 p.v. and T1 d.p. had the highest sensitivity in the central zone.

Complementary imaging of ultrasound and PET/CT: A new opportunity?

AIM: To evaluate the effectiveness of complementary imaging of high-resolution ultrasound including CEUS with PET/CT for tissue characterization and tumor detection. MATERIAL AND METHODS: 100 patients were examined with PET/CT and US/CEUS between January 2018 until February 2020. All patients underwent PET/CT followed by selective US/CEUS within 4 weeks. Comparison regarding concordant or diverging findings in PET/CT and US. Analysis of the differences concerning the lesions number of found by PET/CT and US/CEUS or the possibility of a secured diagnosis following ultrasound causing therapeutic changes. RESULTS: Diverging findings regarding the number of liver lesions in PET/CT and CEUS were found in 35 out of 64 patients (54%). Regarding renal lesions, a more definite diagnosis following ultrasound, causing a change of therapeutic approach, was achieved in 89%. Concordant results in PET/CT and US were found in 83% of patients with splenic and nodal findings. In 78% of patients with increased musculoskeletal or soft tissue tracer uptake, US was able to make a secured diagnosis with therapeutic changes. CONCLUSION: The present results indicate a strong benefit of complementary imaging of PET/CT and selective, high-resolution ultrasound especially in patients with liver, renal and musculoskeletal or soft tissue findings.

Prediction of transarterial chemoembolization (TACE) outcome by pre- and postinterventional 13C-methacetin breath test.

BACKGROUND AND OBJECTIVE: Liver function is one of the most important parameters for the outcome of transarterial chemoembolization (TACE). The liver maximum capacity (LiMAx) test is a bedside test that provides a real-time option for liver function testing. The objective of this pilot study was to investigate the suitability of the LiMAX test for predicting the TACE outcome. METHODS: 20 patients with intermediate-stage hepatocellular carcinoma (HCC) received a LiMAx test 24 h pre and post TACE. In addition, laboratory values were collected to determine liver function and model for endstage liver disease (MELD) scores. The success of TACE was assessed 6 weeks post intervention by morphological imaging tests using modified response evaluation criteria in solid tumors (mRECIST). RESULTS: Patients with an objective response (OR = CR + PR) according to mRECIST post TACE had significantly higher values in the pre-interventional LiMAx test than patients with a non-OR (PD or SD) post TACE (r(14) = 0.62, p = 0.01). Higher pre-interventional LiMAx values therefore indicate OR. Patients with a disease control (DC = CR + PR + SD) according to mRECIST post TACE had significantly higher values in the pre-interventional LiMAx test than patients with a non-DC (PD) post TACE (r(14) = 0.65, p = 0.01). Higher pre-interventional LiMAx values therefore indicate DC. The point biserial correlations of LiMAx values pre and post TACE with the outcome OR or DC were descriptively stronger than those of MELD with OR or DC. This suggests that the LiMAx test correlates better with the treatment response than the MELD score. CONCLUSIONS: For the first time, we were able to show in our study that patients who are scheduled for TACE could benefit from a LiMAx test to be able to estimate the benefit of TACE. The higher the pre-interventional LiMAx values, the higher the benefit of TACE. On the other hand, laboratory parameters summarized in the form of the MELD score had significantly less descriptive correlation with the TACE outcome.

Modified Split-Scan Computed Tomography (CT) Diagnostics of Severely Injured Patients: First Results from a Level I Trauma Center Using a Dedicated Head-and-Neck CT-Angiogram for the Detection of Cervical Artery Dissections.

INTRODUCTION: Traumatic cervical artery dissections are associated with high mortality and morbidity in severely injured patients. After finding even higher incidences than reported before, we decided to incorporate a dedicated head-and-neck computed tomography angiogram (CT-A) in our imaging routine for patients who have been obviously severely injured or, according to trauma mechanism, are suspected to be severely injured. MATERIALS AND METHODS: A total of 134 consecutive trauma patients with an ISS ≥ 16 admitted to our level I trauma center during an 18 month period were included. All underwent standardized whole-body CT in a 256-detector row scanner with a dedicated head-and-neck CT-A realized as single-bolus split-scan routine. Incidence, mortality, patient and trauma characteristics, and concomitant injuries were recorded and analyzed in patients with carotid artery dissection (CAD) and vertebral artery dissection (VAD). RESULTS: Of the 134 patients included, 7 patients had at least one cervical artery dissection (CeAD; 5.2%; 95% CI 1.5-9.0%). Six patients (85.7%) had carotid artery dissections, with one patient having a CAD of both sides and one patient having a CAD and contralateral VAD combined. Two patients (28.6%) showed a VAD. Overall mortality was 14.3%, neurologic morbidity was 28.6%. None of the patients showed any attributable neurologic symptoms on admission. The new scanning protocol led to further 5 patients with suspected CeAD during the study period, all ruled out by additional magnetic resonance imaging with angiogram (MRI/MR-A). CONCLUSION: A lack of specific neurologic symptoms on admission urges the need for a dedicated imaging pathway for severely injured patients, reliable for the detection of cervical artery dissections. Although our modified CT protocol with mandatory dedicated CT-A led to false positives requiring additional magnetic resonance imaging, it likely helped reduce possible therapeutic delays.

Evaluation of Alterations to Bile Ducts and Laboratory Values During the First 3 Months After Irreversible Electroporation of Malignant Hepatic Tumors.

PURPOSE: To assess the incidence and evolution of biliary alterations adjacent to the ablation area in patients with hepatic malignancies during the first 3 months after percutaneous irreversible electroporation (IRE) and to investigate associated changes in laboratory values. MATERIAL AND METHODS: Bile ducts located within a ≤1.0 cm radius of the ablation zone were analyzed in 45 patients by preinterventional and postinterventional MRI (1-3 days, 6 weeks, and 3 months after IRE). Moreover, levels of alkaline phosphatase (AP) and serum bilirubin (SB) were examined for evidence of bile duct injury. Biliary alterations and the presence of postinterventional-elevated laboratory levels were correlated with features of the lesions, patients, ablation procedures, and laboratory values. RESULTS: A total of 80 bile ducts were located within a 1.0 cm radius of the ablation zone: 59 were encased, 16 were abutting and 5 were located within a radius of 0.1-1.0 cm of the ablation area. In total, 38 biliary injuries (narrowing, n=22; dilatation, n=14; biloma, n=2) were detected, 3 cases of narrowing occurred for the first time 6 weeks and 3 months after IRE, 21 alterations (dilatation: n=9; narrowing; n=10; biloma: n=2) had resolved during the first 6 weeks, 1 alteration (dilatation: n=1) had resolved by the last follow-up control. Three months after IRE, 19 patients showed elevated levels of AP, whereas SB levels were increased in 10 cases. No significant association between biliary alterations or postinterventional-elevated laboratory values and the investigated characteristics of lesions, patients, ablation procedures or laboratory values could be proven. CONCLUSION: Different alterations of bile ducts adjacent to an IRE ablation zone are common, of which dilatation and especially narrowing commonly represent a long-term complication after IRE. Moreover, a definite correlation between the frequently observed prolonged post-ablative elevation of AP- and SB-levels and the postinterventional biliary alterations could not be proven.

Changes in gadoxetic-acid-enhanced MR imaging during the first year after irreversible electroporation of malignant hepatic tumors.

PURPOSE: To evaluate the appearance and size of ablation zones in gadoxetic-acid-enhanced magnetic resonance imaging (MRI) during the first year after irreversible electroporation (IRE) of primary or secondary hepatic malignancies and to investigate potential correlations to clinical features. MATERIAL AND METHODS: The MRI-appearance of the ablation area was assessed 1-3 days, 6 weeks, 3 months, 6 months, 9 months and 1 year after IRE. The size of the ablation zone and signal intensities of each follow-up control were compared. Moreover, relationships between clinical features and the MRI-appearance of the ablation area 1-3 days after IRE were analyzed. RESULTS: The ablation zone size decreased from 5.6 ± 1.4 cm (1-3 days) to 3.7±1.2 cm (1 year). A significant decrease of central hypointensities was observed in T2-blade- (3 months), T2 haste- (6 weeks; 3 months; 6 months; 1 year), T1 arterial phase- (3 months; 1 year), and diffusion-sequences (6 weeks; 3 months; 6 months; 9 months; 1 year). The unenhanced T1-sequences showed significantly increasing central hypointensities (6 weeks; 3 months; 6 months; 9 months; 1 year). Significantly increasing peripheral hypointensities were detected in T1 arterial phase- (3 months; 6 months; 9 months; 1 year) and in T1 portal venous phase-sequences (6 weeks; 3 months; 6 months; 9 months; 1 year). Peripheral hypointensities of unenhanced T1-sequences decreased significantly 1 year after IRE. 1-3 days after IRE central T1 portal venous hypo- or isointensities were detected significantly more often than hyperintensities, if more than 3 IRE electrodes were used. CONCLUSION: Hepatic IRE results in continuous reduction of ablation zone size during the first postinterventional year. In addition to centrally decreasing T1-signal and almost steadily increasing signal in the enhanced T2 haste-, diffusion- and T1 arterial phase-sequences, there is a trend toward long-term decreasing T1 arterial- and portal venous MRI-signal intensity of the peripheral ablation area, probably representing a region of reversible electroporation.

Safety margin assessment after microwave ablation of liver tumors: inter- and intrareader variability.

Background The aim of the study was to evaluate the inter- and intrareader variability of the safety margin assessment after microwave ablation of liver tumors using post-procedure computed tomography (CT) images as well as to determine the sensitivity and specificity of identification remnant tumor tissue. Patients and methods A retrospective analysis of 58 patients who underwent microwave ablation (MWA) of primary or secondary liver malignancies (46 hepatocellular carcinoma, 9 metastases of a colorectal cancer and 3 metastases of pancreatic cancer) between September 2017 and June 2019 was conducted. Three readers estimated the minimal safety margin in millimeters using side-by-side comparison of the 1-day pre-ablation CT and 1-day post-ablation CT and judged whether ablation was complete or incomplete. One reader estimated the safety margin again after 6 weeks. Magnetic resonance imaging (MRI) after 6 weeks was the gold standard. Results The intraclass correlation coefficient (ICC) for estimation of the minimal safety margin of all three readers was 0.357 (95%-confidence interval 0.194-0.522). The ICC for repeated assessment (reader 1) was 0.774 (95%-confidence interval 0.645-0.860). Sensitivity and specificity of the detection of complete tumor ablation, defined as no remnant tumor tissue in 6 weeks follow-up MRI, were 93%/82%/82% and 33%/17%/83%, respectively. Conclusions In clinical practice, the safety margin after liver tumor ablation is often assessed using side-by-side comparison of CT images. In the study, we were able to show, that this technique has a poor reliability (ICC 0.357). From our point of view, this proves the necessity of new technical procedures for the assessment of the safety distance.

Improvement of the primary efficacy of microwave ablation of malignant liver tumors by using a robotic navigation system.

Background The aim of the study was to assess the primary efficacy of robot-assisted microwave ablation and compare it to manually guided microwave ablation for percutaneous ablation of liver malignancies. Patients and methods We performed a retrospective single center evaluation of microwave ablations of 368 liver tumors in 192 patients (36 female, 156 male, mean age 63 years). One hundred and nineteen ablations were performed between 08/2011 and 03/2014 with manual guidance, whereas 249 ablations were performed between 04/2014 and 11/2018 using robotic guidance. A 6-week follow-up (ultrasound, computed tomography and magnetic resonance imaging) was performed on all patients. Results The primary technique efficacy outcome of the group treated by robotic guidance was significantly higher than that of the manually guided group (88% vs. 76%; p = 0.013). Multiple logistic regression analysis indicated that a small tumor size (≤ 3 cm) and robotic guidance were significant favorable prognostic factors for complete ablation. Conclusions In addition to a small tumor size, robotic navigation was a major positive prognostic factor for primary technique efficacy.