Remotely Controlled Electrochemical Degradation of Metallic Implants.

Biodegradable medical implants promise to benefit patients by eliminating risks and discomfort associated with permanent implantation or surgical removal. The time until full resorption is largely determined by the implant's material composition, geometric design, and surface properties. Implants with a fixed residence time, however, cannot account for the needs of individual patients, thereby imposing limits on personalization. Here, an active Fe-based implant system is reported whose biodegradation is controlled remotely and in situ. This is achieved by incorporating a galvanic cell within the implant. An external and wireless signal is used to activate the on-board electronic circuit that controls the corrosion current between the implant body and an integrated counter electrode. This configuration leads to the accelerated degradation of the implant and allows to harvest electrochemical energy that is naturally released by corrosion. In this study, the electrochemical properties of the Fe-30Mn-1C/Pt galvanic cell model system is first investigated and high-resolution X-ray microcomputed tomography is used to evaluate the galvanic degradation of stent structures. Subsequently, a centimeter-sized active implant prototype is assembled with conventional electronic components and the remotely controlled corrosion is tested in vitro. Furthermore, strategies toward the miniaturization and full biodegradability of this system are presented.

Inferior vena cava-syndrome.

Inferior vena cava syndrome (IVCS) is caused by agenesis, compression, invasion, or thrombosis of the IVC, or may be associated with Budd-Chiari syndrome. Its incidence and prevalence are unknown. Benign IVCS is separated from malignant IVCS. Both cover a wide clinical spectrum reaching from asymptomatic to highly symptomatic cases correlated to the underlying cause, the acuity, the extent of the venous obstruction, and the recruitment and development of venous collateral circuits. Imaging is necessary to determine the underlying cause of IVCS and to guide clinical decisions. Interventional therapy has changed the therapeutic approach in symptomatic patients. This article provides an overview over IVCS and focuses on interventional therapeutic methods and results.

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.

Superior vena cava syndrome.

The superior vena cava syndrome (SVCS) is caused by compression, invasion, and/or thrombosis of the superior vena cava and/or the brachiocephalic veins. Benign SVCS is separated from malignant SVCS. SVCS comprises a broad clinical spectrum reaching from asymptomatic cases to rare life-threatening emergencies with upper airway obstruction and increased intracranial pressure. Symptoms are correlated to the acuity and extent of the venous obstruction and inversely correlated to the development of the venous collateral circuits. Imaging is necessary to determine the exact underlying cause and to guide further interventions. Interventional therapy has widely changed the therapeutic approach in symptomatic patients. This article provides an overview over this complex syndrome and focuses on interventional therapeutic methods and results.

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.

Characterization of Focal Liver Lesions using CEUS and MRI with Liver-Specific Contrast Media: Experience of a Single Radiologic Center.

AIM: The purpose of this study was to compare contrast-enhanced ultrasound (CEUS), magnetic resonance imaging (MRI) using liver-specific contrast agent and a combination of both for the characterization of focal liver lesions (FLL). METHODS: 83 patients with both benign and malignant liver lesions were examined using CEUS and MRI after the intravenous administration of liver-specific contrast media. All patients had inconclusive results from prior imaging examinations. Histopathological specimens could be obtained in 53 patients. Ultrasound was performed using a multi-frequency curved probe (1 - 6 MHz) after the injection of 1 - 2.4 ml ultrasound contrast media. The sensitivity, specificity, positive predictive value and negative predictive value of CEUS, MRI and a combination of both (CEUS + MRI) were compared. RESULTS: The sensitivity, specificity, positive and negative predictive values regarding lesion classification were 90.9 %, 70.6 %, 92.3 % and 66.6 %, respectively, for CEUS; 90.9 %, 82.4 %, 95.2 % and 70.0 %, respectively, for MRI; and 96.9 %, 70.6 %, 92.7 % and 85.7 % respectively, for CEUS + MRI. There were no statistically significant differences. 6 malignant lesions were missed using CEUS or MRI alone (false negatives). The use of both modalities combined reduced the false-negative results to 2. CONCLUSION: CEUS and MRI with liver-specific contrast media are very reliable and of equal informative value in the characterization of focal liver lesions. The number of false-negative results can be decreased using a combination of the two methods.

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.

Evaluation of a Robotic Assistance-System For Percutaneous Computed Tomography-Guided (CT-Guided) Facet Joint Injection: A Phantom Study.

BACKGROUND The aim of this study was to compare robotic assisted and freehand facet joint puncture on a phantom model in regards to time requirements and puncture accuracy. MATERIAL AND METHODS Forty facet joints were punctured, 20 using a robotic guidance system and 20 using a freehand procedure. Side and height of the facet joints were randomized and identical for both groups. Procedural accuracy, defined as axial and sagittal deviation, as well as the number of corrections were assessed. Procedure times for each step were documented and time requirements for pre-positioning, reconstruction, planning, and total intervention were calculated. RESULTS Total procedure time for robotic guidance was 259±111 seconds versus 119±77 seconds for freehand procedure (p=1.0). Procedural accuracy for robotic guidance was significantly higher with 0 corrections versus 1.3 corrections for freehand procedure (p=0.02). Needle deviation in the robotics arm was 0.35±1.1 mm in the axial and 2.15±1.2 mm in the sagittal reconstruction. CONCLUSIONS Robotic assisted puncture of the facet joint allowed accurate positioning of the needle with a lower number of needle readjustments. Higher procedural accuracy was marginally offset by a slightly longer intervention time.

Factors associated with short-term local recurrence of liver cancer after percutaneous ablation using irreversible electroporation: a prospective single-center study.

PURPOSE: To evaluate the risk factors associated with short-term local recurrence of malignant liver lesions after irreversible electroporation (IRE). MATERIALS AND METHODS: Thirty-nine consecutive patients (79 malignant liver lesions) were treated with IRE, of whom 14 were excluded from the analysis (including 12 without 6 mo of follow-up and two with incomplete ablation). The remaining 25 patients (aged 59.4 y ± 11.2) had 48 malignant liver lesions, including 22 hepatocellular carcinomas (HCCs), six cholangiocellular carcinomas, and 20 metastatic liver cancers. Multivariate analyses were used to evaluate the associations of risk factors with early recurrence. The characteristics of patients, lesions, and IRE procedures were assessed by logistic regression. RESULTS: Fourteen of the 48 treated lesions (29.2%) showed early local recurrence after 6 months. Tumor volume (< 5 cm(3) vs ≥ 5 cm(3); P = .022) and underlying disease type (HCC, cholangiocellular carcinoma, or metastatic disease; P = .023) were independently associated with early local recurrence. However, distances to the surrounding portal veins (< 0.5 cm vs ≥ 0.5 cm; P = .810), hepatic veins (P = .170), hepatic arteries (P = .761), and bile ducts (P = .226) were not significantly associated with local recurrence. CONCLUSIONS: Because short distances to the surrounding vessels were not associated with early local recurrence, percutaneous IRE might provide an alternative treatment option for perivascular tumors. However, patients with larger tumor volumes appeared to be poor candidates for percutaneous IRE. Regarding the different types of treated lesions, patients with HCC had significantly better outcomes.

Irreversible electroporation ablation of malignant hepatic tumors: subacute and follow-up CT appearance of ablation zones.

PURPOSE: To describe findings on contrast-enhanced computed tomography (CT) images of malignant hepatic tumors 24-72 hours after percutaneous ablation by irreversible electroporation (IRE) and at midterm follow-up. MATERIALS AND METHODS: Retrospective analysis of 52 malignant liver tumors-30 primary hepatic tumors and 22 hepatic metastases-in 34 patients (28 men and 6 women, mean age 64 y) treated by IRE ablation was performed. Ablation zones were evaluated by two examiners in a consensus reading by means of a dual-phase CT scan (consisting of a hepatic arterial and portal venous phase) performed 24-72 hours after IRE ablation and at follow-up. RESULTS: During the portal venous phase, ablation zones either were homogeneously hypoattenuating (n = 36) or contained heterogeneously isoattenuating or hyperattenuating (n = 16) foci, or both, in a hypoattenuating area. Of 52 lesions, 38 included gas pockets. Peripheral contrast enhancement of the ablation defect was evident in 23 tumors during the arterial phase and in 36 tumors during the portal venous phase. Four tumors showed intralesional abscesses after the intervention. At follow-up (mean, 4.7 mo), the mean volume of the ablation defects was reduced to 29% of their initial value. CONCLUSIONS: Because normal findings on contrast-enhanced CT images after IRE ablation may be very similar to the typical characteristics of potential complications following ablation, such as liver abscesses, CT scans must be carefully analyzed to distinguish normal results after intervention from complications requiring further treatment.

Update on Percutaneous Local Ablative Procedures for the Treatment of Hepatocellular Carcinoma. / Aktueller Stand zu perkutanen lokalablativen Verfahren beim hepatozellulären Karzinom.

BACKGROUND: Hepatocellular carcinoma (HCC) is the fifth most common tumor worldwide. Because many hepatocellular carcinomas are already unresectable at the time of initial diagnosis, percutaneous tumor ablation has become established in recent decades as a curative therapeutic approach for very early (BCLC 0) and early (BCLC A) HCC. The aim of this paper is to provide a concise overview of the percutaneous local ablative procedures currently in use, based on their technical characteristics as well as clinical relevance, taking into account the current body of studies. MATERIALS AND METHODS: The literature search included all original papers, reviews, and meta-analyses available via MEDLINE and Pubmed on the respective percutaneous ablation procedures; the primary focus was on randomized controlled trials and publications from the last 10 years. RESULTS AND CONCLUSIONS: Radiofrequency ablation (RFA) and microwave ablation (MWA) are well-established procedures that are considered equal to surgical resection in the treatment of stage BCLC 0 and A HCC with a diameter up to 3 cm due to their strong evidence in international and national guidelines. For tumors with a diameter between 3 and 5 cm, the current S3 guidelines recommend a combination of transarterial chemoembolization (TACE) and thermal ablation using RFA or MWA as combination therapy is superior to thermal ablation alone in tumors of this size and shows comparable results to surgical resection in terms of overall survival. Alternative, less frequently employed thermal procedures include cryotherapy (CT) and laser ablation (LA). Non-thermal procedures include irreversible electroporation (IRE), interstitial brachytherapy (IBT), and most recently, electrochemotherapy (ECT). Due to insufficient evidence, these have only been used in individual cases and within the framework of studies. However, the nonthermal methods are a reasonable alternative for ablation of tumors adjacent to large blood vessels and bile ducts because they cause significantly less damage to these structures than thermal ablation methods. With advances in the technology of the respective procedures, increasingly good evidence, and advancements in supportive techniques such as navigation devices and fusion imaging, percutaneous ablation procedures may expand their indications for the treatment of larger and more advanced tumors in the coming years. KEY POINTS: · RFA and MWA are considered equal to surgical resection as a first-line therapy for the curative treatment of stage BCLC 0 and A HCCs with a diameter of up to 3 cm.. · For HCCs with a diameter between 3 and 5 cm, a combination of TACE and RFA or MWA is recommended. This combination therapy yields results comparable to those of surgical resection in terms of overall survival.. · Due to insufficient evidence, alternative ablation methods have only been used in individual cases and within the framework of studies. However, nonthermal methods, such as IRE, IBT, and, most recently, ECT, are a reasonable alternative for ablation of HCCs adjacent to large blood vessels and bile ducts because they cause significantly less damage to these structures than thermal ablation methods.. CITATION FORMAT: · Luerken L, Haimerl M, Doppler M et al. Update on Percutaneous Local Ablative Procedures for the Treatment of Hepatocellular Carcinoma. Fortschr Röntgenstr 2022; 194: 1075 - 1086.

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.

Assessment of Rib Fracture in Acute Trauma Using Automatic Rib Segmentation and a Curved, Unfolded View of the Ribs: Is There a Saving of Time?

Introduction: The fast and accurate diagnosis of rib fractures in polytrauma patients is important to reduce the mortality rate and relieve long-term pain and complications. Aim: To evaluate the diagnostic accuracy and potential time savings using automatic rib segmentation and a curved, unfolded view for the detection of rib fractures in trauma patients. Methods: The multidetector computed tomography raw data of 101 consecutive polytrauma patients (72 men; mean age 45 years, age range 17 to 84 years) admitted to a university hospital were retrospectively post-processed to generate a curved, unfolded view of the rib cage. No manual corrections were performed. Patients with reconstruction errors and movement artifacts were excluded from further analysis. All fractures were identified and classified by the study coordinator using the original data set. Two readers (reader 1 and reader 2) evaluated the original axial sections and the unfolded view, separately. The fracture locations, fracture type, and reading times were recorded. Sensitivity and specificity were calculated on a per-rib basis using a ratio estimator. Cohen's Kappa was calculated as an index of inter-rater agreement. Results: 26 of 101 patients (25.7%) were excluded from further analysis owing to breathing artifacts (6.9%) or incorrect centerline computation in the unfolded view (18.8%). In total, 107 (5.9%) of 1800 ribs were fractured in 25 (33%) of 75 patients. The unfolded view had a sensitivity/specificity of 81%/100% (reader 1) and 71%/100% (reader 2) compared to 94%/100% (reader 1; p = 0.002/p = 0.754) and 63%/99% (reader 2; p < 0.001/p = 0.002). The sensitivity (reader 1; reader 2) was poor for buckled fractures (31%; 38%), moderate for undislocated fractures (78%; 62%), and good for dislocated fractures (94%; 90%). The assessment of the unfolded view was performed significantly faster than that of the original layers (19.5 ± 9.4 s vs. 68.6 ± 32.4 s by reader 1 (p < 0.001); 24.1 ± 9.5 s vs. 40.2 ± 12.7 s by reader 2 (p < 0.001)). Both readers demonstrated a very high interobserver agreement for the unfolded view (κ = 0.839) but only a moderate agreement for the original view (κ = 0.529). Conclusion: Apart from a relatively high number of incorrect centerline reconstructions, the unfolded view of the rib cage allows a faster diagnosis of dislocated rib fractures.

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.

Stereotactic Microwave Ablation of Hepatocellular Carcinoma: The Impact of Tumor Size and Minimal Ablative Margin on Therapeutic Success.

BACKGROUND: Microwave ablation (MWA) has gained relevance in the treatment of hepatic malignancies and especially in hepatocellular carcinoma (HCC), and it is an important alternative to surgery. The purpose of the study was to evaluate whether the minimal ablative margin (MAM) or the initial tumor size has a greater effect on the success of stereotactic MWA of HCC regarding the time to local tumor progression (LTP) and overall survival (OS). METHODS: 88 patients, who received stereotactic MWA of 127 tumor lesions with a curative intention were included in this single-center, retrospective study. The MAM was evaluated in a side-by-side comparison of pre- and post-ablative, contrast-enhanced slice imaging. A Cox proportional hazard model with a frailty term was computed to assess the influence of the MAM and the maximum tumor diameter on the time to LTP and the OS. RESULTS: The maximum tumor diameter was identified as a significant positive predictor for LTP (hazard ratio 1.04, 95% CI 1.00-1.08, p = 0.03), but it was not a significant positive predictor for the OS (p = 0.20). The MAM did not have a significant influence on LTP-free survival (p = 0.23) and OS (p = 0.67). CONCLUSION: For the successful stereotactic MWA of HCC, the MAM and maximum tumor diameter might not have an influence on the OS, but the maximum tumor diameter seems to be an independent predictor of the time to LTP.