Re-irradiation for humeral epicondylitis : Retrospective analysis of 99 elbows.

BACKGROUND: Humeral epicondylitis is a common elbow disease. The prevalence is about 1.7%. One of the most effective treatment options is radiotherapy. Some authors mention that they apply a second or third course of radiation for recurrent pain or partial or no response to the initial course. As the results of a re-irradiation have not been systematically analyzed, the aim of this study was to document the results of repeated radiation treatment and to identify those patients who will benefit. MATERIAL AND METHODS: The analysis was performed on patients from three German radiotherapy institutions and included 99 re-irradiated elbows. Pain was documented with the numeric rating scale (NRS). Evaluation of the NRS was done before and directly after each radiation therapy as well as for the follow-up of 24 months. The median age of the patients was 51 years with 48.8% male and 51.2% female patients. Repeated radiation was indicated because the initial radiotherapy resulted in 39.7% of no response, in 41.0% of partial response and in 19.3% of recurrent pain. RESULTS: A significant response to re-irradiation was found. For the whole sample the median pain score was 6 before re-irradiation, 3 after 6 weeks, 2 after 12 months and 1 after 24 months. The percentage of patients being free of pain or with very little pain was 50.9% 24 months after re-irradiation. All subgroups, notably those with no response, partial response and recurrent pain had a significant reduction of pain. CONCLUSION: Re-irradiation of humeral epicondylitis is an effective and safe treatment. All subgroups showed a good response to re-irradiation for at least 24 months.

18F-FDG PET/MRI compared with clinical and serological markers for monitoring disease activity in patients with aortitis and chronic periaortitis.

OBJECTIVES: We compared the diagnostic value of fully integrated 18F-FDG PET/MRI to that of clinical and serological markers for monitoring disease activity in patients with aortitis/chronic periaortitis (A/CPA) during immunosuppressive therapy. METHODS: Patients positive for A/CPA at the initial and at least 2 consecutive PET/MRI studies were included for retrospective analysis. Imaging (qualitative and quantitative analysis), clinical, and serologic (C-reactive protein, erythrocyte sedimentation rate) assessments were determined at each visit, and their findings compared. Differences in various PET/MRI parameters, clinical symptoms, and serologic markers during therapy between first and second visits were tested for statistical significance. Spearman's rank correlation coefficient was calculated to relate imaging to serologic marker changes between the first 2 visits. RESULTS: Serial assessments were performed in 12 patients with A/CPA, over 34 visits. PET/MRI suggested active disease in 22/34 (64.7%) studies, whereas clinical assessment and serological analysis were positive in only 18/34 (52.9%) and 17/34 (50%) cases, respectively. Disease activity assessment differed between PET/MRI, and clinical and serological markers, in 8/34 (23.5%) and 9/34 (26.5%) cases, respectively. Imaging and serologic parameters (p < 0.009) and clinical symptoms (p = 0.063) predominantly improved at the second visit. Changes from the first to the second visit were not correlated between PET/MRI and serologic markers. CONCLUSIONS: Fully integrated 18F-FDG PET/MRI provides a comprehensive imaging approach with data on vascular/perivascular inflammation that is complementary to clinical and laboratory assessments. This highlights the potential value of imaging-based disease activity monitoring, which might have a crucial impact on clinical management in patients with A/CPA.

Radiotherapy of epicondylitis humeri : Analysis of 138 elbows treated with a linear accelerator.

BACKGROUND: Epicondylitis humeri is a common disease with a prevalence of 1.7%. One of the treatment options is radiotherapy. Most published cases were treated with the orthovoltage technique or with a telecobalt device. Many radiotherapy institutions are nowadays using linear accelerators for treatment of epicondylitis humeri. There is a discussion whether the treatment results with linear accelerators are comparable to the orthovoltage technique. The aim of this study was to analyze the results of radiotherapy with a linear accelerator for epicondylitis humeri. MATERIAL AND METHODS: The analysis was performed on patients of 2 German radiotherapy institutions and included 138 irradiated elbows. Pain was documented with the numeric rating scale (NRS). Evaluation of the NRS was done before and directly after each radiation therapy course as well as for the follow-up of 24 months. The median age of the patients was 49 years with 48.4% male and 51.6% female. In all, 81.0% were suffering from from epicondylitis humeri radialis while 16.7% were treated because of epicondylitis humeri ulnaris. In 65.4% the dominant arm was treated. RESULTS: A significant response to radiotherapy could be found. For the whole sample the median pain was 7 on the NRS before radiotherapy, 4 after 6 weeks and 0 after 12 and 24 months. The percentage of patients with 0 or 1 on the NRS was 64.6% 12 months after radiotherapy. All subgroups, notably those with epicondylitis humeri radialis and epicondylitis humeri ulnaris had a significant reduction of pain. CONCLUSION: Radiotherapy of epicondylitis humeri with a linear accelerator is an effective treatment without showing side effects. All analyzed subgroups showed a good response to radiotherapy for at least 24 months.

Is low dose radiotherapy an effective treatment for Baker's cyst?

PURPOSE: Osteoarthritis of the knee is a common disease, often associated with a Baker's cyst. Besides osteoarthritis, also other joint pathologies of the knee can be causative for a Baker's cyst. Radiotherapy is known to be an effective treatment for osteoarthritis, with an anti-inflammatory effect. As the excessive production of synovia usually is associated with intraarticular inflammation, our hypothesis was that radiotherapy might positively influence the synovial production and reduce the volume of a Baker's cyst. MATERIALS AND METHODS: We performed a prospective trial, including 20 knees receiving radiotherapy for knee arthritis. Besides documentation of NRS (numeric rating scale), WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score and Knee Society Score, the volume of the Baker's cyst was calculated for a short- (6 to 12 weeks) and long-term (9 to 12 months) follow-up. Ultrasonic volumetry was performed using an ultrasound device with a high-resolution multifrequency linear probe (6-9 MHz). RESULTS: Low-dose radiotherapy improved NRS, WOMAC score and Knee Society Score significantly. The mean volume of Baker's cyst decreased from 22.3 ml to 10.7 respectively 3.1 ml during follow-up. A decrease in volume of more than 25% compared to the baseline could be achieved for 75% of the patients in the short-term and 79% of the patients in the long-term follow up. CONCLUSION: Radiotherapy of knee osteoarthritis is an effective treatment that decreases the volume of a Baker's cyst. Most patients respond to the treatment. Whether radiotherapy is an effective treatment for Baker's cyst without associated osteoarthritis has to be further examined.

Intraoperative Shear Wave Elastography vs. Contrast-Enhanced Ultrasound for the Characterization and Differentiation of Focal Liver Lesions to Optimize Liver Tumor Surgery.

PURPOSE: Assessment of intraoperative quantitative shear wave elastography (SWE) and contrast-enhanced ultrasound (CEUS) for the characterization of focal liver lesions (FLLs) during liver surgery using postoperative histopathological results as the gold standard. MATERIALS AND METHODS: US data of 79 consecutive patients with 98 FLLs who underwent liver surgery between 08/2015 - 06/2017 were prospectively acquired and retrospectively analyzed. Multifrequency linear/T-shaped probes (6 - 9 MHz) were used to store cine loops of at least 5 s and images of B-mode, SWE and CEUS. The first CEUS loop was continuously documented over 1 min. in each case. Quantitative SWE analysis of FLLs was performed by placing 5 regions of interest to measure shear wave speed (m/s) and stiffness (kPa). CEUS was evaluated during the arterial, portal venous and late phase after i. v. bolus injections of 2.4 - 10 ml sulfur hexafluoride microbubbles. Postoperative histopathology after tumor resection or intraoperative biopsy was obtained to confirm findings of SWE and CEUS. RESULTS: Of 98 FLLs in 79 patients (mean age: 58 years sd ±â€Š12y) 88 were malignant and 10 were benign ranging from 0.69 to 15.2 cm in size (mean: 2.8 cm, sd ±â€Š2.25 cm). SWE characterized 73/88 FLLs correctly as malignant and 7/10 as benign using a cut-off value of 2.5 m/s/21.3 kPa (p < 0.0005). The sensitivity was 83 %, specificity 70 %, accuracy 82 %. CEUS could correctly identify 86/88 malignant and 8/10 benign FLLs. The sensitivity was 98 %, specificity 80 %, accuracy 96 %. SWE could correctly identify 2 malignant FLLs which CEUS falsely characterized as benign. CONCLUSION: Intraoperative CEUS and SWE are excellent tools for the highly accurate visualization, characterization and malignancy assessment of hepatic tumors during liver surgery.

Percutaneous Treatment of Malignant Liver Lesions: Evaluation of Success Using Contrast- Enhanced Ultrasound (CEUS) and Perfusion Software.

AIM: Using new perfusion software for evaluation of the success of percutaneous treatments of malignant liver tumors with CEUS. MATERIALS AND METHODS: Retrospective analysis of 88 patients (74 male, 14 female; 30 - 84 years) with 165 malignant liver lesions. The lesions were 57 metastases and 108 HCCs. The success of interventional treatment (IRE n = 47; RFA n = 38; MWA n = 44; TACE n = 36) was evaluated by CEUS and perfusion software (VueBox®). CEUS was performed after injection of 1 - 2.4 ml of sulfur hexafluoride microbubbles (SonoVue®) using a 1 - 5 MHz convex probe. DICOM loops up to 1 min. in the ablation area were stored digitally in the PACS. Regions of interest (ROI) were manually placed in the center, the margins of the lesions as well as in the surrounding tissue. Using VueBox® peak, time to peak (TTP), mean transit time (mTT), rise time (RT), the wash-in and wash-out rate were calculated for the regions, in order to evaluate the success of the percutaneous treatment after the ablation in comparison to the ceCT/ceMRI up to 6 months after the treatment. RESULTS: There were significant differences in all cases between the center compared to the margins for the main perfusion parameters (peak, mTT, RT) (p < 0.001). Peak, wash-in and wash-out ratios were further analyzed with the type of lesion and the method of ablation. All parameters were significantly different between lesions treated successfully vs. lesions with recurrence. CONCLUSION: A combination of CEUS with perfusion imaging enables critical assessment of successful treatment after percutaneous interventional procedures for a malignant liver lesion.

Bile Duct Injury after Irreversible Electroporation of Hepatic Malignancies: Evaluation of MR Imaging Findings and Laboratory Values.

PURPOSE: To evaluate biliary complications after irreversible electroporation (IRE) of hepatic malignancies. MATERIALS AND METHODS: In 24 patients (17 men; mean age, 59.3 y), bile ducts were located within a 1.0-cm radius of the ablation zone at subacute follow-up (ie, 1­3 d) after percutaneous IRE of 53 hepatic tumors (primary hepatic tumors, n = 14). MR imaging, conducted with a hepatocyte-specific contrast agent before and after treatment, was examined for evidence of bile duct injury. Serum bilirubin and alkaline phosphatase levels measured at subacute and short-term follow-up (ie, 1­2 mo after IRE) were analyzed for evidence of biliary injury. Correlations between bile duct injury and characteristics of patients, lesions, and ablation procedures were assessed by generalized linear models. RESULTS: Fifty-five bile ducts were located within 1.0 cm of an ablation defect. Locations relative to the ablation area were as follows: 33 were encased, 14 were abutting, and 8 were located within a radius of 0.1­1.0 cm of the ablation zone. Subacute follow-up MR images showed 15 bile duct injuries (narrowing, n = 8; dilation, n = 7). At subacute follow-up, three patients showed transient abnormalities of laboratory values (bilirubin, 1.6­5.2 mg/dL). Short-term laboratory values were abnormal in one patient (increase in alkaline phosphatase of 533 U/L vs baseline) as a result of local tumor recurrence. Patient age (continuous, P = .026; < 65 y vs ≥ 65 y, P = .001) was independently associated with post-IRE bile duct injury. CONCLUSIONS: Bile ducts adjacent to an IRE ablation area remain largely unaffected by this procedure.

Percutaneous Ablation of Hepatic Tumors Using Irreversible Electroporation: A Prospective Safety and Midterm Efficacy Study in 34 Patients.

PURPOSE: To evaluate the safety and efficacy of percutaneous irreversible electroporation (IRE) of primary and secondary liver cancer unsuitable for resection or thermal ablation. MATERIALS AND METHODS: In this prospective, single-center study, 65 malignant liver tumors (hepatocellular carcinoma, n = 33; cholangiocellular carcinoma, n = 5; colorectal cancer metastasis, n = 22; neuroendocrine cancer metastasis, n = 3; testicular cancer metastasis, n = 2) in 34 patients (27 men, 7 women; mean age, 59.4 y ± 11.2) were treated. Local recurrence-free survival (LRFS) according to the Kaplan-Meier method was evaluated after a median follow-up of 13.9 months. RESULTS: Median tumor diameter was 2.4 cm ± 1.4 (range, 0.2-7.1 cm). Of 65 tumors, 12 (18.5%) required retreatment because of incomplete ablation (n = 3) or early local recurrence (n = 9). LRFS at 3, 6, and 12 months was 87.4%, 79.8%, and 74.8%. The median time to progressive disease according to modified Response Evaluation Criteria In Solid Tumors was 15.6 months. Overall complication rate was 27.5% with six major complications and eight minor complications. Major complications included diffuse intraperitonal bleeding (n = 1), partial thrombosis of the portal vein (n = 1), and liver abscesses (n = 4). Minor complications were liver hematomas (n = 6) and clinically inapparent pneumothoraces (n = 2). CONCLUSIONS: IRE showed promising results regarding therapeutic efficacy for the percutaneous treatment of liver tumors; however, significant concerns remain regarding its safety.

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.

Full-Core Biopsy Systems Take Larger Liver Tissue Samples with Lower Fragmentation Rates Than Conventional Side-Notch Systems: A Randomized Trial.

BACKGROUND: The aim of this study was to compare the histopathological quality and physical features of the specimen of a full-core end-cut biopsy system with that of the standard side-notch system for liver biopsies. METHODS: A full-core end-cut 16G biopsy device and a standard side-notch 16G needle were used to take biopsies of unclear liver lesions. Patients were randomized in two groups of 16 patients each. The primary endpoint of this prospective study was the core length measured using a dedicated microscope imaging software. Secondary endpoints were the quality of the specimen rated by an independent pathologist unaware of the device (scale from 1 to 5; with 1 as best and 5 as worst), the core diameter (determined by the microscopic imaging software) and presence of fragmentation (evaluated by the pathologist). RESULTS: For the full-core (FC) and side-notch (SN) groups, the mean core length was similar with 13,599 µm and 11,570 µm (p=0.131), respectively. The quality of the specimen was significantly better in the FC-group with an average rating of 1.68 vs 2.50 (p=0.009). The fragmentation rate in the FC-group was statistically significantly lower at 2/27 (7%) than in the SN-group at 13/33 (39%) (p=0.021). The diameter in the FC-group was 1042 µm vs 930 µm in SN-group (p=0.018).

Long-term survival after percutaneous irreversible electroporation of inoperable colorectal liver metastases.

BACKGROUND: For colorectal liver metastases (CRLM) that are not amenable to surgery or thermal ablation, irreversible electroporation (IRE) is a novel local treatment modality and additional option. METHODS: This study is a retrospective long-term follow-up of patients with CRLM who underwent IRE as salvage treatment. RESULTS: Of the 24 included patients, 18 (75.0%) were male, and the median age was 57 (range: 28-75) years. The mean time elapsed from diagnosis to IRE was 37.9±37.3 months. Mean overall survival was 26.5 months after IRE (range: 2.5-69.2 months) and 58.1 months after diagnosis (range: 14.8-180.1 months). One-, three-, and five-year survival rates after initial diagnosis were 100.0%, 79.2%, and 41.2%; after IRE, the respective survival rates were 79.1%, 25.0%, and 8.3%. There were no statistically significant differences detected in survival after IRE with respect to gender, age, T- or N-stage at the time of diagnosis, size of metastases subject to IRE, number of hepatic lesions, or time elapsed between IRE and diagnosis. CONCLUSION: For nonresectable CRLM, long-term survival data emphasize the value of IRE as a new minimally invasive local therapeutic approach in multimodal palliative treatment, which is currently limited to systemic or regional therapies in this setting.

Safety and efficacy of transarterial chemoembolization with degradable starch microspheres (DSM-TACE) in the treatment of secondary liver malignancies.

PURPOSE: To evaluate the safety and efficacy of degradable starch microspheres (DSM) as embolic agents in transarterial chemoembolization (TACE) in the treatment of secondary liver metastases. METHODS: This was a national, multicenter observational study. Primary endpoints were safety and treatment response according to Modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria. RESULTS: A total of 77 DSM-TACE procedures were performed in 20 patients. Minor immediate adverse events (AEs) were epigastric pain with an incidence of 45.5% (35/77), and nausea and vomiting at an incidence of 23.4% (18/77). Delayed minor AEs were epigastric pain in 13/77 (16.9%) treatments and nausea and vomiting in 10 (13.0%) treatments. No severe AEs were documented. Therapeutic efficacy of DSM-TACE procedures according to mRECIST was as follows: complete response 0/77, partial response 17/77, stable disease 33/77 and progressive disease 6/77, no data was available for 21/77 treatments. Overall, objective response was achieved in 8 of 20 patients (40.0%). CONCLUSION: DSM as embolic agent for TACE is safe in the treatment of liver metastases. An objective response in 40.0% of patients and disease control in 64.9% of procedures was achieved, and this should lead to further evaluation of DSM-TACE as treatment option for nonresectable liver metastases.

Transarterial chemoembolization (TACE) with degradable starch microspheres (DSM) in hepatocellular carcinoma (HCC): multi-center results on safety and efficacy.

BACKGROUND: Hepatocellular carcinoma (HCC) is the 3rd leading cause of cancer-related death worldwide. The majority of HCCs are diagnosed in a stage that is not eligible for curative resection. For intermediate stage HCC, transarterial chemoembolization (TACE) is the recommended treatment. We evaluated the safety and efficacy of DSM (degradable starch microspheres) as embolic agent in transarterial chemoembolization (TACE) for the treatment of intermediate stage, non-resectable hepatocellular carcinoma (HCC). METHODS AND FINDINGS: A national, multi-center observational study on the safety and efficacy of DSM-TACE for the treatment of intermediate HCC was conducted. The recruitment period for the study was from January 2010 to June 2014. The primary endpoints were safety and treatment response according to the mRECIST criteria. A total of 179 DSM-TACE procedures in 50 patients were included in the analysis. The therapeutic efficacy assessed with mRECIST was as follows: complete response (n=1; 2 %), 21 partial response (42 %), 13 stable disease (26 %), 9 progressive disease (18 %), and 6 incomplete data (12 %). Thus, the objective response rate was 44% (n=22) and disease control rate was 70% (n=35). A total of 76 immediate adverse events (AE) and 2 severe adverse events (SAE) were recorded. Forty-eight percent of patients (n=24) did not encounter any immediate AE/SAE. Between treatments, a total of 66 AE and one SAE were recorded. Twenty-four patients (48 %) did not encounter any AE/SAE in between treatments. CONCLUSION: The use of DSM as a TACE embolic agent appears to be safe for the treatment of HCC and has promising efficacy.

Impact of Different Embolic Agents for Transarterial Chemoembolization (TACE) Procedures on Systemic Vascular Endothelial Growth Factor (VEGF) Levels.

Background and Aims: Intermediate stage hepatocellular carcinoma (HCC) can be treated by transarterial chemoembolization (TACE). However, there appear to be side effects, such as induction of proangiogenic factors, e.g. vascular endothelial growth factor (VEGF), which have been shown to be associated with a poor prognosis. This prospective study was designed to compare serum VEGF level response after TACE with different embolic agents in patients with HCC. Methods: Patients were assigned to one of three different TACE regimens: degradable starch microspheres (DSM) TACE, drug-eluting bead (DEBDOX) TACE or Lipiodol TACE (cTACE). All patients received 50 mg doxorubicin/m2 body surface area (BSA) during TACE. Serum VEGF levels were assessed before TACE treatment, 24 h post-treatment and 4 weeks later. Results: Twenty-two patients with 30 TACE treatments were enrolled. Compared to baseline VEGF levels, a marked increase was observed for 24 h post-TACE (164% of baseline level) and during the 4-week follow-up (170% of baseline level) only for the cTACE arm (p < 0.05). In contrast, the increase of serum VEGF levels were only 114% and 123% for DEBDOX and 121% and 124% for DSM, respectively. Conclusions: Conventional TACE using Lipiodol shows marked increase in blood levels of the proangiogenic factor VEGF, while DEBDOX and DSM TACE induce only a moderate VEGF response.

Stereotactically-navigated percutaneous Irreversible Electroporation (IRE) compared to conventional IRE: a prospective trial.

Purpose. The purpose of this study was to compare CT-navigated stereotactic IRE (SIRE) needle placement to non-navigated conventional IRE (CIRE) for percutaneous ablation of liver malignancies. Materials and Methods. A prospective trial including a total of 20 patients was conducted with 10 patients in each arm of the study. IRE procedures were guided using either CT fluoroscopy (CIRE) or a stereotactic planning and navigation system (SIRE). Primary endpoint was procedure time. Secondary endpoints were accuracy of needle placement, technical success rate, complication rate and dose-length product (DLP). Results. A total of 20 IRE procedures were performed to ablate hepatic malignancies (16 HCC, 4 liver metastases), 10 procedures in each arm. Mean time for placement of IRE electrodes in SIRE was significantly shorter with 27 ± 8 min compared to 87 ± 30 min for CIRE (p < 0.001). Accuracy of needle placement for SIRE was higher than CIRE (2.2 mm vs. 3.3 mm mean deviation, p < 0.001). The total DLP and the fluoroscopy DLP were significantly lower in SIRE compared to CIRE. Technical success rate and complication rates were equal in both arms. Conclusion. SIRE demonstrated a significant reduction of procedure length and higher accuracy compared to CIRE. Stereotactic navigation has the potential to reduce radiation dose for the patient and the radiologist without increasing the risk of complications or impaired technical success compared to CIRE.

Irreversible Electroporation of Malignant Hepatic Tumors--Alterations in Venous Structures at Subacute Follow-Up and Evolution at Mid-Term Follow-Up.

PURPOSE: To evaluate risk factors associated with alterations in venous structures adjacent to an ablation zone after percutaneous irreversible electroporation (IRE) of hepatic malignancies at subacute follow-up (1 to 3 days after IRE) and to describe evolution of these alterations at mid-term follow-up. MATERIALS AND METHODS: 43 patients (men/women, 32/11; mean age, 60.3 years) were identified in whom venous structures were located within a perimeter of 1.0 cm of the ablation zone at subacute follow-up after IRE of 84 hepatic lesions (primary/secondary hepatic tumors, 31/53). These vessels were retrospectively evaluated by means of pre-interventional and post-interventional contrast-enhanced magnetic resonance imaging or computed tomography or both. Any vascular changes in flow, patency, and diameter were documented. Correlations between vascular change (yes/no) and characteristics of patients, lesions, and ablation procedures were assessed by generalized linear models. RESULTS: 191 venous structures were located within a perimeter of 1.0 cm of the ablation zone: 55 (29%) were encased by the ablation zone, 78 (41%) abutted the ablation zone, and 58 (30%) were located between 0.1 and 1.0 cm from the border of the ablation zone. At subacute follow-up, vascular changes were found in 19 of the 191 vessels (9.9%), with partial portal vein thrombosis in 2, complete portal vein thrombosis in 3, and lumen narrowing in 14 of 19. At follow-up of patients with subacute vessel alterations (mean, 5.7 months; range, 0 to 14 months) thrombosis had resolved in 2 of 5 cases; vessel narrowing had completely resolved in 8 of 14 cases, and partly resolved in 1 of 14 cases. The encasement of a vessel by ablation zone (OR = 6.36, p<0.001), ablation zone being adjacent to a portal vein (OR = 8.94, p<0.001), and the usage of more than 3 IRE probes (OR = 3.60, p = 0.035) were independently associated with post-IRE vessel alterations. CONCLUSION: Venous structures located in close proximity to an IRE ablation zone remain largely unaffected by this procedure, and thrombosis is rare.