Artificial Intelligence for Clinical Interpretation of Bedside Chest Radiographs.

Background Supine chest radiography for bedridden patients in intensive care units (ICUs) is one of the most frequently ordered imaging studies worldwide. Purpose To evaluate the diagnostic performance of a neural network-based model that is trained on structured semiquantitative radiologic reports of bedside chest radiographs. Materials and Methods For this retrospective single-center study, children and adults in the ICU of a university hospital who had been imaged using bedside chest radiography from January 2009 to December 2020 were reported by using a structured and itemized template. Ninety-eight radiologists rated the radiographs semiquantitatively for the severity of disease patterns. These data were used to train a neural network to identify cardiomegaly, pulmonary congestion, pleural effusion, pulmonary opacities, and atelectasis. A held-out internal test set (100 radiographs from 100 patients) that was assessed independently by an expert panel of six radiologists provided the ground truth. Individual assessments by each of these six radiologists, by two nonradiologist physicians in the ICU, and by the neural network were compared with the ground truth. Separately, the nonradiologist physicians assessed the images without and with preliminary readings provided by the neural network. The weighted Cohen κ coefficient was used to measure agreement between the readers and the ground truth. Results A total of 193 566 radiographs in 45 016 patients (mean age, 66 years ± 16 [SD]; 61% men) were included and divided into training (n = 122 294; 64%), validation (n = 31 243; 16%), and test (n = 40 029; 20%) sets. The neural network exhibited higher agreement with a majority vote of the expert panel (κ = 0.86) than each individual radiologist compared with the majority vote of the expert panel (κ = 0.81 to ≤0.84). When the neural network provided preliminary readings, the reports of the nonradiologist physicians improved considerably (aided vs unaided, κ = 0.87 vs 0.79, respectively; P < .001). Conclusion A neural network trained with structured semiquantitative bedside chest radiography reports allowed nonradiologist physicians improved interpretations compared with the consensus reading of expert radiologists. © RSNA, 2022 Supplemental material is available for this article. See also the editorial by Wielpütz in this issue.

Temporary Vascular Occlusion with Retrievable Microvascular Plugs to Protect Normal Liver during Yttrium-90 Radioembolization.

This case series describes a technique to protect nondiseased liver parenchyma during transarterial radioembolization (TARE) using microvascular plugs to occlude nontarget vessels temporarily and protect normal liver. This technique, defined as temporary vascular occlusion, was performed in 6 patients, with complete vessel occlusion obtained in 5 of the 6 patients and partial occlusion with flow reduction in 1 of the 6 patients. A statistically significant (P = .001) dose decrease of 5.7 ± 3.1 times was measured using postadministration yttrium-90 positron emission tomography/computed tomography in the protected zone compared with that in the treated zone.

Perioperative and long-term outcome after ascending aortic and arch repair with elephant trunk and open thoracoabdominal aortic aneurysm repair.

OBJECTIVE: To describe the outcome of open thoracoabdominal aortic aneurysm (TAAA) repair following previous aortic arch repair including elephant trunk (ET) or frozen elephant trunk (FET) for acute and chronic pathologies. METHODS: This was a retrospective, observational, multicenter study including 32 patients treated between 2006 and 2019 in two aortic centers using identical surgical protocols. Assessment focused on perioperative and long-term outcome, namely in-hospital morbidity and mortality, as well as procedure-related reintervention rate and aortic-related mortality rate. Kaplan-Meier curves with 95% confidence intervals were used to analyze the overall survival after surgery within the cohort. RESULTS: Thirty-two patients (mean age, 45.0 ± 13.6 years; 20 males [62.5%]) were treated because of acute (34.38% [n = 11]) or chronic (65.62% [n = 21]) aortic pathologies, including residual dissection following acute, symptomatic type A dissection (n = 7) and symptomatic mega aortic syndrome (n = 4), as well as post-dissection TAAA (n = 18) and asymptomatic mega aortic syndrome (n = 3). Twenty-eight patients (87.5%) received type II repair, and 4 patients (12.5%) received type III repair after previous ascending aorta and arch repair including ET/FET. Concomitant infrarenal and iliac vessel repair was performed in 38.7% (n = 12) and 29.4% (n = 10), respectively. The in-hospital mortality rate was 18.75% (n = 6). Spinal cord ischemia occurred in two cases, both after one-stage emergency procedure with one case of permanent paraplegia. Temporary acute kidney injury occurred in 41.94% (n = 13). The estimated 1-year survival rate was 78.1% (95% confidence interval, 63.9%-95.6%), with a median follow-up time of 1.29 years (interquartile range, 0.26-3.88 years). No procedure-related reinterventions and one case of aortic-related mortality, namely sepsis because of graft infection, was observed. CONCLUSIONS: Open TAAA repair following aortic arch repair including ET or FET because of acute or chronic aortic pathologies is associated with a relevant perioperative morbidity and mortality rate. During follow-up, a low aortic-related mortality rate and procedure-related reintervention rate were observed.

Safety and efficacy of right portal vein embolization in patients with prior left lateral liver resection.

BACKGROUND: In patients with bilobar metastatic liver disease, surgical clearance of both liver lobes may be achieved through multiple-stage liver resections. For patients with extensive disease, a major two-staged hepatectomy consisting of resection of liver segments II and III before right-sided portal vein embolization (PVE) and resection of segments V-VIII may be performed, leaving only segments IV ± I as the liver remnant. PURPOSE: To describe the outcome following right-sided PVE after prior complete resection of liver segments II and III. MATERIAL AND METHODS: In this retrospective study, 15 patients (mean age = 60.4 ± 9.3 years) with liver metastases from colorectal cancer (n = 14) and uveal melanoma (n = 1) who were scheduled to undergo a major two-stage hepatectomy, were included. Total liver volume (TLV) and volume of the future liver remnant (FLR) were measured on pre- and postinterventional computed tomography (CT) scans, and standardized FLR volumes (ratio FLR/TLV) were calculated. Patient data were retrospectively analyzed regarding peri- and postinterventional complications, with special emphasis on liver function tests. RESULTS: The mean standardized post-PVE FLR volume was 26.9% ± 6.4% and no patient developed hepatic insufficiency after the PVE. Based on FLR hypertrophy and liver function tests, all but one patient were considered eligible for the subsequent right-sided hepatectomy. However, due to local tumor progression, only 9/15 patients eventually proceeded to the second stage of surgery.  . CONCLUSION: Right-sided PVE was safe and efficacious in this cohort of patients who had previously undergone a complete resection of liver segments II and III as part of a major staged hepatectomy pathway leaving only segments IV(±I) as the FLR. .

An accelerometer-based guidance device for CT-guided procedures: an improved wireless prototype.

INTRODUCTION: The aim of the study was to demonstrate the feasibility of a prototype for accelerometer-based guidance for percutaneous CT-guided punctures and compare it with free-hand punctures. MATERIAL AND METHODS: The prototype enabled alignment with the CT coordinate system and a wireless connectivity. Its feasibility was tested in a swine cadaver model: 20 out-of-plane device-assisted punctures performed without intermittent control scans (one-step punctures) were evaluated regarding deviation to target and difference between planned and obtained angle. Thereafter, 22 device-assisted punctures were compared with 20 free-hand punctures regarding distance to target, deviation from the planned angle, number of control scans and procedure time. Differences were compared with the Mann-Whitney U-test (p < .05). RESULTS: The one-step punctures revealed a deviation to target of 0.26 ± 0.37 cm (axial plane) and 0.21 ± 0.19 cm (sagittal plane) and differences between planned and performed puncture angles of 0.9 ± 1.09° (axial plane) and 1.15 ± 0.91° (sagittal planes). In the comparative study, device-assisted punctures showed a significantly higher accuracy, 0.20 ± 0.17 cm vs. 0.30 ± 0.21 cm (p < .05) and lower number of required control scans, 1.3 ± 1.1 vs. 3.7 ± 0.9 (p < .05) compared with free-hand punctures. CONCLUSION: The accelerometer-based device proved to be feasible and demonstrated significantly higher accuracy and required significantly less control scans compared to free-hand puncture.

Percutaneous transhepatic biliary drainage (PTBD) in patients with dilated vs. nondilated bile ducts: technical considerations and complications.

OBJECTIVES: The aim of this study was to compare success, technical complexity, and complication rates of percutaneous transhepatic biliary drainage (PTBD) in patients with dilated vs. nondilated bile ducts. METHODS: In a retrospective analysis, we evaluated all consecutive PTBD performed in our department over a period of 5 years. Technical success, technical data (side, fluoroscopy time, radiation dose, amount of contrast media, use of disposable equipment), procedure-related complications and peri-interventional mortality were compared for patients with dilated vs. non-dilated bile ducts. Independent t test and χ2 test were used to evaluate the statistical significance. RESULTS: A total of 253 procedures were performed on 187 patients, of whom 101/253 had dilated bile ducts and 152/253 not. In total, 243/253 procedures were successful. PTBD was significantly more often successful in patients with dilated vs. nondilated bile ducts (150/153 vs. 93/101; p 0.02). Overall complication rate (13%) did not differ significantly between patients with dilated vs. nondilated bile ducts. Procedures in patients with normal, nondilated bile ducts were associated with a significantly higher rate of post-interventional bleeding (5/101 vs. 0/152). Mean fluoroscopy time (42:36 ± 35:39 h vs. 30:28 ± 25:10 h; p 0.002) and amount of contrast media (66 ± 40 ml vs. 52 ± 24 ml; p 0.07) or use of disposables were significantly higher in patients with nondilated ducts. A significantly lower fluoroscopy time and amount of contrast medium were used in left hepatic PTBD. CONCLUSION: Despite the higher technical complexity, PTBD with nondilated bile ducts was associated with similar overall complication rates but higher bleeding complications compared with PTBD with dilated bile ducts. KEY POINTS: • PTBD was associated with similar overall complication rates in patients with dilated vs. nondilated bile ducts. • Although overall complication rates were low, PTBD in patients with nondilated bile ducts was associated with a higher incidence of post-interventional bleeding. • PTBD in patients with nondilated bile ducts is technically more complex.

Induction of Contralateral Hepatic Hypertrophy by Unilobar Yttrium-90 Transarterial Radioembolization versus Portal Vein Embolization: An Animal Study.

PURPOSE: To compare hepatic hypertrophy in the contralateral lobe achieved by unilobar transarterial radioembolization (TARE) versus portal vein embolization (PVE) in a swine model. METHODS: After an escalation study to determine the optimum dose to achieve hypertrophy after unilobar TARE in 4 animals, 16 pigs were treated by TARE (yttrium-90 resin microspheres) or PVE (lipiodol/n-butyl cyanoacrylate). Liver volume was calculated based on CT before treatment and during 6 months of follow-up. Independent t-test (P < .05) was used to compare hypertrophy. The relationship between hypertrophy after TARE and absorbed dose was calculated using the Pearson correlation. RESULTS: At 2 and 4 weeks after treatment, a significantly higher degree of future liver remnant hypertrophy was observed in the PVE group versus the TARE group, with a median volume gain of 31% (interquartile range [IQR]: 16%-66%) for PVE versus 23% (IQR: 6%-36%) for TARE after 2 weeks and 51% (IQR: 47%-69%) for PVE versus 29% (IQR: 20%-50%) for TARE after 4 weeks. After 3 and 6 months, hypertrophy converged without a statistically significant difference, with a volume gain of 103% (IQR: 86%-119%) for PVE versus 82% (IQR: 70%-96%) for TARE after 3 months and 115% (IQR: 70%-46%) for PVE versus 86% (IQR: 58%-111%) for TARE after 6 months. A strong correlation was observed between radiation dose (median 162 Gy, IQR: 139-175) and hypertrophy. CONCLUSIONS: PVE resulted in rapid hypertrophy within 1 month of the procedure, followed by a plateau, whereas TARE resulted in comparable hypertrophy by 3-6 months. TARE-induced hypertrophy correlated with radiation absorbed dose.

Salvage RFA in patients with intrahepatic recurrence after major hepatic surgery for colorectal cancer liver metastases: mid-term outcome.

OBJECTIVES: To evaluate the mid-term outcome of salvage radiofrequency ablation (RFA) treatment in patients who exhibited intrahepatic recurrence after major hepatectomy for colorectal liver metastases (CRCLM). METHODS: Observational study on 23 consecutive patients (mean age 59 ± 9 years; 14/9 male/female) who, after a single (11/23) or multiple rounds (12/23) of major hepatic surgery, developed recurrent CRCLM in the liver remnant. Patients with a maximum of three metastases measuring up to 3 cm, and without relevant extrahepatic disease, underwent CT-guided RFA. Using the Kaplan-Meier-method, median intrahepatic progression-free-survival (ihPFS) and overall survival (OS) times after salvage RFA were compared with the same patients' time between the respective last round of surgery and diagnosis of intrahepatic recurrence leading to RFA. RESULTS: Median follow-up was 26 months (range 12-103 months). Median ihPFS time after RFA was 8 months (range 1-81 months). Median ihPFS time after the respective last round of surgery and RFA in the same patients had been 5 months (range 1-23 months), thus yielding similar ihPFS times after surgery vs. after salvage RFA (p = 0.238; Mood's median test). After RFA, 15/23 (65%) of patients developed new hepatic metastases within the first year post-RFA. Median OS was 37 months, with a 1-year OS rate of 100%, 3-year OS rate of 57%, and 5-year OS rate of 24%. No major complications were observed. CONCLUSIONS: Patients who exhibit intrahepatic recurrence of CRCLM after major hepatectomy will experience intrahepatic recurrence after salvage RFA as well, and after similar time intervals. However, long-term ihPFS may still be achieved in some patients. KEY POINTS: • Patients who exhibit intrahepatic recurrence of colorectal liver metastases after major hepatectomy will experience intrahepatic recurrence after salvage RFA as well, and after similar time intervals. • About two-thirds of all patients develop new metastases elsewhere in the liver within 1 year after RFA. • However, long-term intrahepatic progression-free survival may still be achieved in some patients.

Predictors of Occlusion of Hepatic Blood Vessels after Irreversible Electroporation of Liver Tumors.

PURPOSE: To examine predictors of midterm occlusion in portal and hepatic veins within or adjacent to the ablation zone after irreversible electroporation (IRE) of liver tumors. MATERIALS AND METHODS: This retrospective cohort analysis included 39 patients who underwent CT-guided IRE of liver tumors. Vessels within or adjacent to the ablation zone were identified on CT images acquired immediately after the procedure, and the positional relationships with the ablation zone (within/adjacent), locations (proximal/distal), and diameters (< 4 mm or ≥ 4 mm) were evaluated. Using contrast-enhanced follow-up scans, each vessel was classified as patent, stenosed, or occluded. Associations between vessel occlusion and each variable were investigated. RESULTS: Overall, 33 portal veins and 64 hepatic veins were analyzed. Follow-up scans showed occlusion in 12/33 (36.7%) portal veins and 17/64 (26.6%) hepatic veins. Vessels within the ablation zone were occluded significantly more frequently than vessels adjacent to the ablation zone (portal: 55.6% [10/18] vs 13.3% [2/15], P = .04; hepatic: 45.4% [15/33] vs 6.4% [2/31], P = .011). Vessels with a diameter < 4 mm were also occluded significantly more frequently than vessels with a diameter ≥ 4 mm (portal: 72.7% [8/11] vs 18.1% [4/22], P = .011; hepatic: 54.8% [17/31] vs 0% [0/33], P < .001). The respective positive and negative predictive values for occlusion of vessels categorized as both within and < 4 mm were 88% (7/8) and 82% (20/25) for portal veins and 79% (15/19) and 96% (43/45) for hepatic veins. CONCLUSIONS: Midterm vessel occlusion after liver IRE could be predicted with relatively high accuracy by assessing ablation location and vessel diameter.

Single-needle electroporation and interstitial electrochemotherapy: in vivo safety and efficacy evaluation of a new system.

OBJECTIVES: We conducted an in vivo trial to investigate the safety and efficacy of a newly developed system for the application of a combined therapy consisting of irreversible electroporation (IRE) and electrochemotherapy (IRECT) in the liver. The system is conceived as a single-needle multitined applicator with expandable electrodes that allow interstitial injection of fluids, e.g., chemotherapy. METHODS: Experiments were conducted in ten domestic pigs. The applicator was placed in different liver lobes under CT guidance. In one lobe, the applicator was used for conventional IRE (1500 V, 120 pulses, pulse length 100 µs). In the other lobe, the same procedure was performed preceded by the injection of a doxorubicin mixture through the expandable electrodes (IRECT). Contrast-enhanced CT and MRI were performed on days 1, 3, and 7 after the procedure. Accordingly, three animals were sacrificed on days 1, 3, and 7 after the imaging and ablation volumes were evaluated histopathologically. Related t test was used to compare the groups. RESULTS: Technical success was achieved in 9/10 experiments. One animal deceased during the intervention because of ventricular fibrillation. Follow-up CT 1 and 3 days after intervention showed a significant (p < 0.05) difference in the ablation volumes of IRECT vs IRE, respectively, of 4.47 ± 1.78 ml vs 2.51 ± 0.93 ml and of 3.39 ± 1.05 vs 1.53 ± 0.78 ml. CONCLUSIONS: IRECT using the newly developed system proved to be effective and provided significantly larger ablation volumes compared with IRE alone. However, ECG triggering is a necessary prerequisite to allow a safe application of the system. KEY POINTS: • Working on the geometry of the IRE applicator in terms of expandable electrodes may overcome the current limitations of IRE resulting from the placement of multiple electrodes. • Efficacy of IRE ablations can be enhanced by the interstitial application of chemotherapy in the periphery of ablation areas.

Preoperative Embolization of the Celiac Axis or Common Hepatic Artery before Distal Pancreatectomy with Resection of the Celiac Axis.

Patients with locally advanced pancreatic cancer who undergo distal pancreatectomy with resection of the celiac axis (CA) are at risk for postoperative hepatic or gastric ischemia if collateral blood flow from the superior mesenteric artery (SMA) via the gastroduodenal artery is insufficient. This study presents a technique for preoperative angiographic evaluation of these collateral vessels by using an AMPLATZER Vascular Plug to temporarily occlude the CA or common hepatic artery while simultaneously performing digital subtraction angiography of the SMA. If collateral vessels are deemed sufficient, the plug can subsequently be released for permanent occlusion with the intent to enhance the blood flow in these collateral vessels.

Operator radiation exposure during radioembolisation of the liver: transfemoral versus transradial access using real-time dose monitoring.

In this study, operator radiation exposure is compared utilising transradial access (TRA) versus transfemoral access (TFA) during transarterial radioembolisation (TARE) of liver tumors. Patients who underwent Y90 TARE between May 2017 and April 2018 were included. Electronic medical records and interventional data were collected and the following parameters evaluated: technical success, fluoroscopy time, operator radiation exposure and rate of operator radiation exposure per fluoroscopy time. Statistical analysis was performed with the Wilcoxon rank-sum test. A total of 22 patients (12 males, 10 females) underwent 22 procedures. A total of 12 procedures were performed via TFA and 10 via TRA. Technical success was 100% in both groups. Median fluoroscopy time (10 minutes for TRA vs 6.4 minutes for TFA, p = 0.082) was not statistically different. Both operator radiation exposure (49 vs 4.2 µSv, p = 0.00016) and rate of operator exposure (4.9 vs 0.71 µSv per min, p = 0.00021) were significantly higher in the TRA versus TFA groups, respectively.

Plant-based model for the visual evaluation of electroporated area after irreversible electroporation and its comparison to in-vivo animal data.

Electroporation (EP) is widely used in medicine, such as cancer treatment, in form of electrochemotherapy or irreversible electroporation (IRE). For EP device testing, living cells or tissue inside a living organism (including animals) are needed. Plant-based models seem to be a promising alternative to substitute animal models in research. The aim of this study is to find a suitable plant-based model for visual evaluation of IRE, and to compare the geometry of electroporated areas with in-vivo animal data.For this purpose, a variety of fruit and vegetables were selected and visually evaluated after 0/1/2/4/6/8/12/16/24 h post-EP. Apple and potato were found to be suitable models as they enabled a visual evaluation of the electroporated area. For these models, the size of the electroporated area was determined after 0/1/2/4/6/8/12/16/24 h. For apples, a well-defined electroporated area was visual within two hours, while in potatoes it reached a plateau after eight hours only. The electroporated area of apple, which showed the fastest visual results was then compared to a retrospectively evaluated swine liver IRE dataset which had been obtained for similar conditions. The electroporated area of the apple and swine liver both showed a spherical geometry of comparable size. For all experiments, the standard protocol for human liver IRE was followed. To conclude, potato and apple were found to be suitable plant-based models for the visual evaluation of electroporated area after irreversible EP, with apple being the best choice for fast visual results. Given the comparable range, the size of the electroporated area of the apple may be promising as a quantitative predictor in animal tissue. Even if plant-based models cannot completely replace animal experiments, they can be used in the early stages of EP device development and testing, decreasing animal experiments to the necessary minimum.

Calcification of the visceral aorta and celiac trunk is associated with renal and allograft outcomes after deceased donor liver transplantation.

PURPOSE: Atherosclerosis affects clinical outcomes in the setting of major surgery. Here we aimed to investigate the prognostic role of visceral aortic (VAC), extended visceral aortic (VAC+), and celiac artery calcification (CAC) in the assessment of short- and long-term outcomes following deceased donor orthotopic liver transplantation (OLT) in a western European cohort. METHODS: We retrospectively analyzed the data of 281 consecutive recipients who underwent OLT at a German university medical center (05/2010-03/2020). The parameters VAC, VAC+, or CAC were evaluated by preoperative computed tomography-based calcium quantification according to the Agatston score. RESULTS: Significant VAC or CAC were associated with impaired postoperative renal function (p = 0.0016; p = 0.0211). Patients with VAC suffered more frequently from early allograft dysfunction (EAD) (38 vs 26%, p = 0.031), while CAC was associated with higher estimated procedural costs (p = 0.049). In the multivariate logistic regression analysis, VAC was identified as an independent predictor of EAD (2.387 OR, 1.290-4.418 CI, p = 0.006). Concerning long-term graft and patient survival, no significant difference was found, even though patients with calcification showed a tendency towards lower 5-year survival compared to those without (VAC: 65 vs 73%, p = 0.217; CAC: 52 vs 72%, p = 0.105). VAC+ failed to provide an additional prognostic value compared to VAC. CONCLUSION: This is the first clinical report to show the prognostic role of VAC/CAC in the setting of deceased donor OLT with a particular value in the perioperative phase. Further studies are warranted to validate these findings. CT computed tomography, OLT orthotopic liver transplantation.

Augmented Reality-Assisted CT-Guided Puncture: A Phantom Study.

PURPOSE: To investigate the feasibility of a novel augmented reality system for CT-guided liver interventions and to compare it with free-hand interventions in a phantom setting. METHODS AND MATERIALS: A newly developed augmented reality interface was used, with projection of CT-imaging in multiplanar reconstruction and live rendering of the needle position, a bull`s eye view of the needle trajectory and a visualization of the distance to the target. Punctures were performed on a custom-made abdominal phantom by three interventional radiologists with different levels of expertise. Time and needle placement accuracy were measured. Two-tailed Wilcoxon signed rank test (p < 0.05) was performed to evaluate intraparticipant difference. RESULTS: Intraparticipant puncture times were significantly shorter for each operator in the augmented reality condition (< 0.001 for the resident, < 0.001 for the junior staff member and 0.027 for the senior staff member). The junior staff member had an improvement in accuracy of 1 mm using augmented reality (p 0.026); the other two participants showed no significant improvement regarding accuracy. CONCLUSION: In this small series, it appears that the novel augmented reality system may improve the speed of CT-guided punctures in the phantom model compared to the free-hand procedure while maintaining a similar accuracy.

Reliability as a Precondition for Trust-Segmentation Reliability Analysis of Radiomic Features Improves Survival Prediction.

Machine learning results based on radiomic analysis are often not transferrable. A potential reason for this is the variability of radiomic features due to varying human made segmentations. Therefore, the aim of this study was to provide comprehensive inter-reader reliability analysis of radiomic features in five clinical image datasets and to assess the association of inter-reader reliability and survival prediction. In this study, we analyzed 4598 tumor segmentations in both computed tomography and magnetic resonance imaging data. We used a neural network to generate 100 additional segmentation outlines for each tumor and performed a reliability analysis of radiomic features. To prove clinical utility, we predicted patient survival based on all features and on the most reliable features. Survival prediction models for both computed tomography and magnetic resonance imaging datasets demonstrated less statistical spread and superior survival prediction when based on the most reliable features. Mean concordance indices were Cmean = 0.58 [most reliable] vs. Cmean = 0.56 [all] (p < 0.001, CT) and Cmean = 0.58 vs. Cmean = 0.57 (p = 0.23, MRI). Thus, preceding reliability analyses and selection of the most reliable radiomic features improves the underlying model's ability to predict patient survival across clinical imaging modalities and tumor entities.

Long loop technique with bifemoral access as salvage technique for repositioning of dislodged port catheters.

BACKGROUND: Repositioning of dislocated port systems' catheters is usually performed with a pigtail catheter and/or a goose snare. In case of an inaccessible port catheter tip due to thrombosis, this classic approach may be not successful. For these cases, we describe a long loop bailout technique with bifemoral access. TECHNIQUE: Via a right transfemoral access, a first attempt to reposition the dislodged port catheter using pigtail catheter and goose snare was performed. After an unsuccessful attempt and delineation of thrombosis of the catheter tip, the contralateral femoral vein was subsequently punctured and a sheath was placed. Through both vascular sheaths, pigtail catheter and goose wire were advanced distally to the catheter. The guidewire in the pigtail catheter was snared, thus creating a "Long loop" configuration. Pulling down both catheters simultaneously with improved stability allowed to detach the catheter tip from the vessel wall and replacement into the superior vena cava was possible. Refinement of catheter tip position was done using the goose snare. This technique was applied on 5 patients with dislodged port catheters in the jugular vein (2/5), the innominate vein (1/5), the subclavian vein (1/5) and the azygos vein (1/5) with a technical success of 100%. No complications were observed. CONCLUSION: The Long loop technique can be used as salvage approach to reposition a dislodged catheter in case of failure with pigtail catheter and goose snare.

Recanalization and Stenting of the Celiac and the Superior Mesenteric Artery Supported by Use of a Steerable Introducer Sheath: Report on 2 Years' Experience.

PURPOSE: To compare technical parameters and success of recanalization of celiac (CA) or superior mesenteric artery (SMA) with usage of steerable vs not steerable introducer sheaths. METHODS: A retrospective analysis was performed on all consecutive patients who underwent recanalization with stent implantation of CA or SMA between 2015 and 2019. Data regarding technical success (successful stent placement with restoration of sufficient blood flow by the first attempt without changing kind of introducer sheath or access site), indication for treatment, vascular access, kind of introducer sheath, fluoroscopy time and radiation dose were collected. Preinterventional CT were analyzed to classify the difficulty of catheterization of target vessels. Technical parameters were compared with independent t-test (p ≤ 0.05). RESULTS: 66 patients underwent recanalization of CA or SMA. Usage of steerable introducer sheaths was associated with higher technical success compared to not steerable introducer sheaths with transfemoral approach respectively of 8/8 vs 15/19 for the CA and 11/11 vs 17/20 for the SMA. Steerable introducer sheaths were used in recanalization considered more technically difficult compared to not steerable introducer sheaths (58% vs 33%). Usage of steerable introducer sheath showed a statistically significant reduction of radiation dose in the recanalization of the SMA (respectively 32035 ± 15716 cGy cm2 vs 60102 ± 28432 cGy cm2; p = 0.005). CONCLUSION: Even if used in more difficult interventions, steerable introducer sheaths showed a higher technical success compared to not steerable introducer sheaths with transfemoral access.

Advancing diagnostic performance and clinical usability of neural networks via adversarial training and dual batch normalization.

Unmasking the decision making process of machine learning models is essential for implementing diagnostic support systems in clinical practice. Here, we demonstrate that adversarially trained models can significantly enhance the usability of pathology detection as compared to their standard counterparts. We let six experienced radiologists rate the interpretability of saliency maps in datasets of X-rays, computed tomography, and magnetic resonance imaging scans. Significant improvements are found for our adversarial models, which are further improved by the application of dual-batch normalization. Contrary to previous research on adversarially trained models, we find that accuracy of such models is equal to standard models, when sufficiently large datasets and dual batch norm training are used. To ensure transferability, we additionally validate our results on an external test set of 22,433 X-rays. These findings elucidate that different paths for adversarial and real images are needed during training to achieve state of the art results with superior clinical interpretability.

Endovascular Revascularization with Stent Implantation in Patients with Acute Mesenteric Ischemia due to Acute Arterial Thrombosis: Clinical Outcome and Predictive Factors.

PURPOSE: To determine 30-day-mortality rates and identify predictors for survival in patients undergoing endovascular revascularization for acute mesenteric ischemia (AMI) due to occlusion of the celiac (CA) or superior mesenteric artery (SMA) from arterial thrombosis in the setting of atherosclerosis at the vessel origin. MATERIALS AND METHODS: A retrospective analysis on patients who underwent acute endovascular revascularization to treat AMI caused by thrombotic occlusion of the CA and/or SMA between January 2011 and December 2019 was conducted. 30-day-mortality rates were calculated. Univariate binomial logistic regression analyses (p < 0.05) were performed to assess whether the following factors were associated with 30-day mortality: sex, age, history of smoking, history of abdominal angina, signs of bowel necrosis on pre-interventional CT, one- vs. two-vessel disease, patency of the inferior mesenteric artery, outpatient or inpatient occurrence of ischemia, onset of AMI during ITU stay, elevated pre-interventional serum lactate levels, total leukocyte count, platelet/lymphocyte ratio and neutrophil/lymphocyte ratio. RESULTS: 40 patients were included in this analysis. 30-day-mortality rate was 25/40 (62.5%). Median overall survival of patients who survived the first 30 days was 36 ± 18 months. None of the analyzed factors was statistically significantly associated with 30-day mortality. CONCLUSION: Although mortality of patients with AMI due to acute arterial thrombosis remains high, almost 40% of patient who underwent emergent endovascular revascularization survived longer than one month. Since no predictors for the outcome in these patients were identified, all patients with AMI should be offered an immediate revascularization effort.