Somatic RIT1 delins in arteriovenous malformations hyperactivate RAS-MAPK signaling amenable to MEK inhibition.

Arteriovenous malformations (AVM) are benign vascular anomalies prone to pain, bleeding, and progressive growth. AVM are mainly caused by mosaic pathogenic variants of the RAS-MAPK pathway. However, a causative variant is not identified in all patients. Using ultra-deep sequencing, we identified novel somatic RIT1 delins variants in lesional tissue of three AVM patients. RIT1 encodes a RAS-like protein that can modulate RAS-MAPK signaling. We expressed RIT1 variants in HEK293T cells, which led to a strong increase in ERK1/2 phosphorylation. Endothelial-specific mosaic overexpression of RIT1 delins in zebrafish embryos induced AVM formation, highlighting their functional importance in vascular development. Both ERK1/2 hyperactivation in vitro and AVM formation in vivo could be suppressed by pharmacological MEK inhibition. Treatment with the MEK inhibitor trametinib led to a significant decrease in bleeding episodes and AVM size in one patient. Our findings implicate RIT1 in AVM formation and provide a rationale for clinical trials with targeted treatments.

Outcome of bleomycin electrosclerotherapy of slow-flow malformations in adults and children.

OBJECTIVES: To evaluate the safety and clinical outcome of bleomycin electrosclerotherapy (BEST) for treating extracranial slow-flow malformations. METHODS: In this retrospective investigation of a multicenter cohort presenting symptomatic slow-flow malformations, patient records were analyzed with respect to procedural details and complications. A treatment-specific, patient-reported questionnaire was additionally evaluated, obtained 3-12 months after the last treatment, to assess the subjective outcomes, including mobility, aesthetic aspects, and pain, as well as the occurrence of postprocedural skin hyperpigmentation. All outcome parameters were compared according to patients' age. RESULTS: Overall, 325 BEST treatments were performed in 233 patients after intralesional and/or intravenous bleomycin injection. The total complication rate was 10.2% (33/325), including 29/352 (8.9%) major complications. Patient-reported mobility decreased in 10/133 (8.8%), was stable in 30/113 (26.5%), improved in 48/113 (42.5%), and was rated symptom-free in 25/113 (22.1%) patients. Aesthetic aspects were rated impaired compared to baseline in 19/113 (16.8%), stable in 21/133 (18.6%), improved in 62/113 (54.9%), and perfect in 11/133 (9.7%) patients. Postprocedural skin hyperpigmentation occurred in 78/113 (69%) patients, remaining unchanged in 24/78 (30.8%), reduced in 51/78 (65.5%), and completely resolved in 3/78 (3.8%) patients. The median VAS pain scale was 4.0 (0-10) preprocedural and 2.0 (0-9) postprocedural. Children/adolescents performed significantly better in all parameters compared to adults (≥ 16 years) (mobility, p = 0.011; aesthetic aspects, p < 0.001; pain, p < 0.001). CONCLUSIONS: BEST is effective for treating slow-flow vascular malformations, with few but potentially significant major complications. Regarding patient-reported outcomes, children seem to benefit better compared to older patients, suggesting that BEST should not be restricted to adults. CLINICAL RELEVANCE STATEMENT: Bleomycin electrosclerotherapy is a safe and effective approach and therapy should not be restricted to adults due to good clinical outcomes in children.

Pulmonary lesions in early response assessment in pediatric Hodgkin lymphoma: prevalence and possible implications for initial staging.

BACKGROUND: Disseminated pulmonary involvement in pediatric Hodgkin lymphoma (pHL) is indicative of Ann Arbor stage IV disease. During staging, it is necessary to assess for coexistence of non-malignant lung lesions due to infection representing background noise to avoid erroneously upstaging with therapy intensification. OBJECTIVE: This study attempts to describe new lung lesions detected on interim staging computed tomography (CT) scans after two cycles of vincristine, etoposide, prednisolone, doxorubicin in a prospective clinical trial. Based on the hypothesis that these new lung lesions are not part of the underlying malignancy but are epiphenomena, the aim is to analyze their size, number, and pattern to help distinguish true lung metastases from benign lung lesions on initial staging. MATERIALS AND METHODS: A retrospective analysis of the EuroNet-PHL-C1 trial re-evaluated the staging and interim lung CT scans of 1,300 pediatric patients with HL. Newly developed lung lesions during chemotherapy were classified according to the current Fleischner glossary of terms for thoracic imaging. Patients with new lung lesions found at early response assessment (ERA) were additionally assessed and compared to response seen in hilar and mediastinal lymph nodes. RESULTS: Of 1,300 patients at ERA, 119 (9.2%) had new pulmonary lesions not originally detectable at diagnosis. The phenomenon occurred regardless of initial lung involvement or whether a patient relapsed. In the latter group, new lung lesions on ERA regressed by the time of relapse staging. New lung lesions on ERA in patients without relapse were detected in 102 (7.8%) patients. Pulmonary nodules were recorded in 72 (5.5%) patients, the majority (97%) being<10 mm. Consolidations, ground-glass opacities, and parenchymal bands were less common. CONCLUSION: New nodules on interim staging are common, mostly measure less than 10 mm in diameter and usually require no further action because they are most likely non-malignant. Since it must be assumed that benign and malignant lung lesions coexist on initial staging, this benign background noise needs to be distinguished from lung metastases to avoid upstaging to stage IV disease. Raising the cut-off size for lung nodules to ≥ 10 mm might achieve the reduction of overtreatment but needs to be further evaluated with survival data. In contrast to the staging criteria of EuroNet-PHL-C1 and C2, our data suggest that the number of lesions present at initial staging may be less important.

Additive value of transarterial embolization to systemic sirolimus treatment in kaposiform hemangioendothelioma.

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor in children, which can be accompanied by life-threatening thrombocytopenia, referred to as Kasabach-Merritt phenomenon (KMP). The mTOR inhibitor sirolimus is emerging as targeted therapy in KHE. As the sirolimus effect on KHE occurs only after several weeks, we aimed to evaluate whether additional transarterial embolization is of benefit for children with KHE and KMP. Seventeen patients with KHE and KMP acquired from 11 hospitals in Germany were retrospectively divided into two cohorts. Children being treated with adjunct transarterial embolization and systemic sirolimus, and those being treated with sirolimus without additional embolization. Bleeding grade as defined by WHO was determined for all patients. Response of the primary tumor at 6 and 12 months assessed by magnetic resonance imaging (MRI), time to response of KMP defined as thrombocyte increase >150 × 103 /µL, as well as rebound rates of both after cessation of sirolimus were compared. N = 8 patients had undergone additive embolization to systemic sirolimus therapy, sirolimus in this group was started after a mean of 6.5 ± 3 days following embolization. N = 9 patients were identified who had received sirolimus without additional embolization. Adjunct embolization induced a more rapid resolution of KMP within a median of 7 days vs 3 months; however, tumor response as well as rebound rates were similar between both groups. Additive embolization may be of value for a more rapid rescue of consumptive coagulopathy in children with KHE and KMP compared to systemic sirolimus only.

Mosaic RASopathy due to KRAS variant G12D with segmental overgrowth and associated peripheral vascular malformations.

Oncogenic RAS variants lead to constitutive overactivation and increased signal transduction into downstream pathways. They are found as somatic driver events in various types of human cancer. In a somatic mosaic status, the same RAS variants have been associated with a wide spectrum of focal or segmental tissue dysplasia and overgrowth including various types of congenital nevi, vascular malformations, and other changes (mosaic RASopathies). We present a 3-year-old male patient with segmental overgrowth of the subcutaneous fatty tissue of the right lower extremity with colocalized arteriovenous and capillary malformations and dysplastic draining veins in combination with talipes equinovarus of the right foot. In tissue biopsies of the affected extremity, we identified a mosaic KRAS variant, c.35G>A (p.Gly12Asp), while this variant was absent in the DNA extracted from a biopsy of the normal extremity. This report provides further evidence for the wide clinical and phenotypic variability associated with mosaic KRAS variants. The described pattern confirms that the combination of segmental overgrowth and vascular anomalies in the form of arteriovenous and capillary malformations is a possible manifestation of a mosaic RASopathy. The accurate genetic diagnosis is crucial for molecular-targeted therapy, which might be a future therapeutic target for mosaic RASopathies.

Fluoroscopy-guided endoscopic sclerotherapy: a novel hybrid approach for symptomatic rectosigmoidal venous malformation (with video).

BACKGROUND AND AIMS: Recommendations for the treatment of lower GI bleeding do not include bleeding from venous malformations (VMs). The aim of this study was to delineate the usefulness of a novel hybrid intervention (fluoroscopy-guided endoscopic sclerotherapy) for the treatment of symptomatic VMs in the rectosigmoidal colon with bleeding. METHODS: The magnetic resonance images of 421 patients with VM, referred to multicenter vascular anomaly centers from 2009 to 2017, were analyzed retrospectively. Treatment was performed for all patients who experienced bleeding from rectosigmoidal VMs using fluoroscopy-guided endoscopic sclerotherapy with polidocanol foam as a novel approach. RESULTS: A total of 27 patients displayed VM in the rectosigmoidal area. Eleven of these presented with acute or previous bleeding and received treatment. Active bleeding was observed in 8 patients (72.7%), whereas 3 patients (27.3%) had signs of previous bleeding. Six of the 11 patients had anemia (54.5%). There were no adverse events within 24 hours of the intervention. In a 2-year follow-up period, only 1 patient (9.1%) presented with recurrent bleeding after 13 months and was successfully treated again with fluoroscopy-guided endoscopic sclerotherapy. CONCLUSIONS: Fluoroscopy-guided endoscopic sclerotherapy was shown to be a safe and effective treatment of symptomatic VMs of the rectosigmoidal area. Thus, fluoroscopy-guided endoscopic sclerotherapy should be considered for patients with bleeding from VMs of the rectosigmoid after a comprehensive workup and interdisciplinary case discussion.

CT after Endovascular Repair of Abdominal Aortic Aneurysms: Diagnostic Accuracy of Diameter Measurements for the Detection of Aneurysm Sac Enlargement.

PURPOSE: To evaluate the diagnostic accuracy of diameter measurements for the detection of aneurysm volume increase during follow-up after endovascular aortic repair (EVAR) of abdominal aortic aneurysms (AAAs). MATERIALS AND METHODS: This retrospective study analyzed 100 pairs of follow-up computed tomography scans randomly selected from an EVAR database (male/female ratio, 91/9; mean age, 71 y; bifurcated and aortouniiliac stent grafts, 96% and 4%, respectively; mean interval, 359 d). Five maximum diameter (Dmax) values were measured (anteroposterior, transverse, axial, coronal, and perpendicular). Aneurysm sac volume was measured by manual segmentation and used as the standard of reference. Overall, 37% of patients had a persistent type II endoleak. RESULTS: The anteroposterior, transverse, axial, coronal, and perpendicular Dmax values increased in 39 patients (mean, 4.3 mm), 30 patients (mean, 4.0), 35 patients (mean, 3.9 mm), 43 patients (mean, 3.9 mm), and 41 patients (mean, 4.3 mm), respectively. Aneurysm sac volume increased in 39 patients (mean, 25.7 cm3). The cutoff levels according to the reporting standard for aneurysm sac enlargement (diameter ≥ 5.0 mm, volume ≥ 5.0%) had sensitivity/specificity rates of 29%/95%, 33%/97%, 29%/99%, 33%/93%, and 38%/96%, respectively, for the five Dmax values. The reference standards failed to detect aneurysm volume increase in 72%, 67%, 72%, 61%, and 67% of patients, respectively, with persistent type II endoleak. CONCLUSIONS: Depending on the chosen cutoff value, diameter measurements showed low to moderate sensitivity for the detection of aneurysm volume increase. The diameter measurements failed to detect aneurysm enlargement in a large number of patients with persistent type II endoleak after EVAR of AAA.

Venous Malformations: Phleboliths Correlate With the Presence of Arteriovenous Microshunts.

OBJECTIVE: The objective of this study was to identify differences between venous malformations (VMs) with arteriovenous (AV) microshunts and VMs without AV microshunts. MATERIALS AND METHODS: In this retrospective study, 83 patients with untreated VMs of the extremities underwent a prospectively defined MRI protocol performed at 3 T. MR images were reviewed to determine localization and extent of each VM and tissue involvement. The VM volume and the lesion volume relative to body surface were measured. The number of phleboliths within the lesions was determined. Using time-resolved MR angiography, the hemodynamic subtype (VM with AV microshunts versus VM without AV microshunts) was classified, and the interval between the onset of arterial enhancement and lesion enhancement (tonset) was measured. Clinical data were reviewed to determine patient demographic characteristics, the onset of symptoms, the frequency of thrombophlebitis, and the pain score. RESULTS: Of the 83 patients, 56 (67%) presented with AV microshunts. The tonset (p ≤ 0.001), absolute and relative lesion volume (p = 0.001), and number of phleboliths (p = 0.038) differed significantly between these two subgroups. With use of a multivariable regression model, the strongest indicator for VM with AV microshunts was the presence of more than two phleboliths (odds ratio, 2.80; p = 0.007). No differences were noted regarding patient demographic characteristics and history or lesion morphologic features or anatomy. CONCLUSION: Occurrence of AV microshunts in untreated VM is a frequent phenomenon. This hemodynamic subtype is significantly associated with phleboliths and large lesions. The subtypes did not differ in terms of history and clinical course.

Time-resolved magnetic resonance angiography (MRA) at 3.0 Tesla for evaluation of hemodynamic characteristics of vascular malformations: description of distinct subgroups.

OBJECTIVES: Quantitative evaluation of hemodynamic characteristics of arteriovenous and venous malformations using time-resolved magnetic resonance angiography (MRA) at 3.0 Tesla. METHODS: Time-resolved MRA with interleaved stochastic trajectories (TWIST) at 3.0 Tesla was studied in 83 consecutive patients with venous malformations (VM) and arteriovenous malformations (AVM). Enhancement characteristics were calculated as percentage increase of signal intensity above baseline over time. Maximum percentage signal intensity increase (signalmax), time intervals between onset of arterial enhancement and lesion enhancement (tonset), and time intervals between beginning of lesion enhancement and maximum percentage of lesion enhancement (tmax) were analyzed. RESULTS: All AVMs showed a high-flow hemodynamic pattern. Two significantly different (p < 0.001) types of venous malformations emerged: VMs with arteriovenous fistulas (AVF) (median signalmax 737 %, IQR [interquartile range] = 511 - 1182 %; median tonset 5 s, IQR = 5 - 10 s; median tmax 35 s, IQR = 26 - 40 s) and without AVFs (median signalmax 284 %, IQR = 177-432 %; median tonset 23 s, IQR = 15 - 30 s; median tmax 60 s, IQR = 55 - 75 s). CONCLUSIONS: Quantitative evaluation of time-resolved MRA at 3.0 Tesla provides hemodynamic characterization of vascular malformations. VMs can be subclassified into two hemodynamic subgroups due to presence or absence of AVFs. KEY POINTS: • Time-resolved MRA at 3.0 Tesla provides quantitative hemodynamic characterization of vascular malformations. • Malformations significantly differ in time courses of enhancement and signal intensity increase. • AVMs show a distinctive high-flow hemodynamic pattern. • Two significantly different types of VMs emerged: VMs with and without AVFs.

Ethanolgel sclerotherapy of venous malformations improves health-related quality-of-life in adults and children - results of a prospective study.

OBJECTIVES: To assess the treatment-induced changes of health-related quality-of-life (HRQoL) in patients with venous malformations (VM) who underwent ethanol gel sclerotherapy. METHODS: The prospective study in children and adults was approved by the local ethics committee. 31 patients (mean age 23.42 years, range 6.6 - 46.5; 26 female, 5 male) with VM were included. Patients' self-assessed HRQoL was measured before and after treatment using psychometrically validated questionnaires for adults and children. Differences were analysed with a paired t test. RESULTS: 58 sclerotherapy sessions were performed. The Physical Component Summary (PCS) at baseline was 43.69 and increased significantly (p = 0.01122) to 48.95 after treatment. The bodily pain (BP) scale increased significantly from 37.94 to 48.56 (p = 0.00002), the general health (GH) scale increased significantly from 46.69 to 52.17 (p = 0.00609). Baseline Physical Summary Score (PHS) in children increased significantly after treatment (p < 0.00001) from 25.25 to 45.89. The baseline Psychosocial Summary Score (PSS) in children was 51.08 and increased significantly (p = 0.00031) after treatment to 58.84. CONCLUSION: Paediatric and adult patients with VM suffer from bodily pain with overall reduced physical functioning. After sclerotherapy, these restrictions are successfully returning to normal levels with a positive effect on mental and psychosocial domains. KEY POINTS: • Sclerotherapy in venous malformation patients has an unknown effect on health-related quality-of-life • Prospective study showed improvements in bodily pain and general health in adults • Children and adults improved from treatment with ethanol gel • Sclerotherapy is an appropriate therapy.

Treatment of Acute Hemoptysis by Bronchial Artery Embolization with the Liquid Embolic Agent Ethylene Vinyl Alcohol Copolymer.

PURPOSE: To determine the technical and clinical success of bronchial artery embolization (BAE) with the liquid embolic agent ethylene vinyl alcohol (EVOH) copolymer in patients with acute hemoptysis. MATERIALS AND METHODS: Thirty-four patients (25 male; mean age, 58 y; range, 13-78 y) who underwent BAE with EVOH were retrospectively reviewed. Reasons for acute hemoptysis included lung cancer (44%), pulmonary metastases (12%), bronchiectasis (21%), arteriovenous malformation (5%), tuberculosis (6%), aspergilloma (3%), acute respiratory distress syndrome (3%), anticoagulant overdose (3%), and scar tissue (3%). Technical and clinical success of BAE were retrospectively assessed. RESULTS: Embolization was technically successful in 94% of patients. Additional embolization material was needed in 4 patients (12%). The immediate clinical success rate was 94% (32 of 34); in 2 patients (6%), hemoptysis recurred immediately after the intervention or could not be stopped. Periinterventional minor complications included headache (n = 1), fever (n = 1), and acute renal failure (n = 1). During follow-up (mean, 8.8 mo), 5 patients had a recurrence of hemoptysis (15%). CONCLUSIONS: The use of EVOH copolymer for BAE in patients with acute hemoptysis is technically successful and safe and has a good clinical outcome with a low number of recurrences.

Ethanol-Gel Sclerotherapy of Venous Malformations: Effectiveness and Safety.

OBJECTIVE: In the treatment of venous malformations, ethanol may be administered in a gelified form to increase local effects and reduce systemic ones. The purpose of this prospective study was to evaluate the efficacy and safety of a commercially available viscous ethanol gel in the treatment of venous malformations. SUBJECTS AND METHODS: Thirty-one patients (mean age, 23.4 years; age range, 6.6-46.5 years) with venous malformations were prospectively scheduled for two ethanol-gel sclerotherapy sessions. Venous malformations were located at the lower extremity (n = 18), the upper extremity (n = 9), and the face (n = 4). Questionnaires to assess pain, clinical examinations, professional photographs, and contrast-enhanced MRI of the venous malformations were performed before and after therapy to measure therapy-induced changes. Two experienced radiologists blinded to the examination date and clinical status compared photographs and MR images before and after treatment. RESULTS: A mean of 4.2 mL of ethanol gel were administered per session. The technical success rate was 100%. Clinical success, defined as improvement or resolution of symptoms, was noted in 81% of patients. Mean pain score decreased, and the difference was statistically significant (3.9 vs 3.1, p = 0.005). In 54 treatment sessions where follow-up was available, four minor complications occurred. Comparison of photographs and MR images before and after treatment showed improvement in 35% and 93% of patients, respectively. CONCLUSION: Ethanol gel is an effective and safe sclerosing agent in the treatment of venous malformations.

CT features of early type II endoleaks after endovascular repair of abdominal aortic aneurysms help predict aneurysm sac enlargement.

PURPOSE: To determine computed tomographic (CT) features of early type II endoleaks associated with aneurysm sac enlargement after endovascular aortic aneurysm repair (EVAR) of abdominal aortic aneurysm. MATERIALS AND METHODS: Institutional review board approval was not required for this retrospective study. The authors reviewed imaging and clinical data from 56 patients (seven women, 49 men; mean age ± standard deviation, 71 years ± 7.9; age range, 52-85 years) with early type II endoleak who had undergone EVAR between December 2002 and December 2011 and who had been followed up with imaging and clinical evaluation for at least 6 months. The number and diameter of all feeding and/or draining arteries were measured, and endoleaks were classified according to their sources into simple inferior mesenteric artery (IMA), simple lumbar artery (LA), complex LA, and complex IMA-LA type II endoleaks. Volume and attenuation of the nidus were measured. Aneurysm enlargement was defined as an increase in the aneurysm volume of more than 5% during follow-up. Simple and multivariate logistic regression analyses were performed to identify independent clinical and imaging variables associated with aneurysm enlargement. RESULTS: Twenty-three of the 56 patients (41%) showed aneurysm sac enlargement during follow-up (mean follow-up, 3.0 years ± 2.0). With the multivariate model, the variables that showed the strongest indicators for aneurysm sac enlargement were complex IMA-LA type II endoleak (odds ratio [OR] = 10.29, P = .004) and the diameter of the largest feeding and/or draining artery (OR = 4.55, P = .013). Patients without complex IMA-LA type II endoleak in whom the largest feeding and/or draining artery was larger than 3.8 mm and patients with a complex IMA-LA type II endoleak in whom the largest feeding and/or draining artery was larger than 2.2 mm were at high risk for aneurysm sac enlargement. CONCLUSION: The strongest indicators for aneurysm sac enlargement are complex IMA-LA type II endoleak and the diameter of the largest feeding and/or draining artery.

Inferior mesenteric arterial type II endoleaks after endovascular repair of abdominal aortic aneurysm: are they predictable?

PURPOSE: To evaluate the association of inferior mesenteric arterial (IMA) type II endoleaks in patients undergoing endovascular aortic aneurysm repair (EVAR) for infrarenal abdominal aortic aneurysm with several morphologic parameters. MATERIALS AND METHODS: Approval of the institutional ethical review committee was not required. This was a retrospective review of 322 computed tomographic angiographic studies that were performed in patients before they underwent elective EVAR for infrarenal abdominal aortic aneurysm. Morphologic parameters evaluated were IMA patency, origin of the IMA in relation to the aneurysm sac, diameter of the IMA, the cross-sectional area of the contrast material-enhanced aortic lumen at the level of the IMA ostium, and the number of additional patent aortic side branches from the aneurysm sac. The association of IMA type II endoleaks with each variable was analyzed by using univariate and multivariate logistic regression models. RESULTS: The diameter of the IMA did not influence the development of IMA type II endoleaks (P = .51). The incidence of these endoleaks was significantly higher in patients with greater cross-sectional area of the aortic lumen at the IMA ostium (P < .001). Patients with an IMA type II endoleak had significantly more patent aortic side branches before EVAR than did patients without an endoleak (3.6 ± 1.7 vs 2.2 ± 1.4; P < .001). According to the final logistic regression model that included cross-sectional area of the aortic lumen at the IMA and the number of aortic side branches as independent predictors, risk for IMA type II endoleaks was determined with a sensitivity of 78% (39 of 50) and a specificity of 79% (92 of 116). CONCLUSION: Cross-sectional area of the contrast-enhanced aortic lumen at the level of the IMA ostium and the number of additional patent aortic side branches are associated with the development of IMA type II endoleaks.

Degradable starch microspheres versus ethiodol and doxorubicin in transarterial chemoembolization of hepatocellular carcinoma.

PURPOSE: To compare outcomes of transarterial chemoembolization with degradable starch microspheres (DSMs) and conventional transarterial chemoembolization with doxorubicin and Ethiodol in patients with unresectable intermediate-stage hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A total of 69 patients underwent 169 chemoembolization procedures with Ethiodol (n = 35) or DSMs (n = 34) as the embolic agent. The same chemotherapeutic agent was used for all patients (50 mg doxorubicin). The primary endpoint was patient survival, and secondary endpoints were local tumor response and incidence of therapy-associated complications with conventional or DSM chemoembolization. Tumor response was evaluated by consensus reading by two radiologists in accordance with modified Response Evaluation Criteria In Solid Tumors. Mean survival was calculated according to Kaplan-Meier analysis, and differences in survival curves were assessed by univariate log-rank test. The statistical significance of quantitative variables was determined by parameter-free Wilcoxon-Mann-Whitney U test. RESULTS: The study groups were similar with regard to demographic data and disease stage. For the DSM chemoembolization group, the objective response rate (ie, complete or partial response) was 44.1%, and the rate of stable disease was 38.2%. The respective rates for the conventional chemoembolization group were 48.6% and 31.4%. Mean survival (P = .337) and complications did not significantly differ between groups (P = .907; P = 1.000). CONCLUSIONS: DSM chemoembolization represents an alternative method of HCC treatment with a safety profile similar to that of conventional transarterial chemoembolization. Regarding local tumor response and overall survival, results of DSM chemoembolization were similar to those of conventional chemoembolization.

Incorporating a-priori information in deep learning models for quantitative susceptibility mapping via adaptive convolution.

Quantitative susceptibility mapping (QSM) has attracted considerable interest for tissue characterization (e.g., iron and calcium accumulation, myelination, venous vasculature) in the human brain and relies on extensive data processing of gradient-echo MRI phase images. While deep learning-based field-to-susceptibility inversion has shown great potential, the acquisition parameters applied in clinical settings such as image resolution or image orientation with respect to the magnetic field have not been fully accounted for. Furthermore, the lack of comprehensive training data covering a wide range of acquisition parameters further limits the current QSM deep learning approaches. Here, we propose the integration of a priori information of imaging parameters into convolutional neural networks with our approach, adaptive convolution, that learns the mapping between the additional presented information (acquisition parameters) and the changes in the phase images associated with these varying acquisition parameters. By associating a-priori information with the network parameters itself, the optimal set of convolution weights is selected based on data-specific attributes, leading to generalizability towards changes in acquisition parameters. Moreover, we demonstrate the feasibility of pre-training on synthetic data and transfer learning to clinical brain data to achieve substantial improvements in the computation of susceptibility maps. The adaptive convolution 3D U-Net demonstrated generalizability in acquisition parameters on synthetic and in-vivo data and outperformed models lacking adaptive convolution or transfer learning. Further experiments demonstrate the impact of the side information on the adaptive model and assessed susceptibility map computation on simulated pathologic data sets and measured phase data.

Review: Flow Diversion for the Treatment of Middle Cerebral Artery Aneurysms.

The invention of flow diverting stents (FDS) is a novel milestone in the field of endovascular aneurysm therapy, promoting physiological healing of the vessel segment contrary to prior deconstructive treatment strategies, such as coiling. The effects of FDS are based on changes in flow patterns, segmental wall stabilization, and the growth of a neointima. Although flow diversion is already well established for cerebral aneurysms in proximal segments, peripheral locations remain challenging. Especially the middle cerebral artery (MCA) with its predominance of non-collateralized perforators and functional end arteries that supply the eloquent areas of the brain is of major concern.The literature was reviewed for flow diversion of the MCA and antiplatelet therapy.Resulting from the special anatomical characteristics of the MCA, FDS implantation in this territory is completely different from the proximal vessel segments. Still, flow diversion represents an effective endovascular strategy, especially in otherwise non-accessible or sufficiently treatable lesions. However, the risk of ischemic adverse events might be increased. Special attention to the individual decision regarding device selection, antiplatelet regimen, and exact definition of the proximal and distal landing zone considering the jailed side branches is essential for a good angiographic and clinical outcome. · MCA aneurysms can be sufficiently treated by FDS.. · The anatomic and hemodynamic characteristics of the MCA result in an increased risk of thromboembolism.. · Individual device selection and antiplatelet regimen are essential for treatment success.. · Schüngel M, Wohlgemuth WA, Elolf E et al. Review: Flow Diversion for the Treatment of Middle Cerebral Artery Aneurysms. Fortschr Röntgenstr 2024; DOI 10.1055/a-2343-0046.

Remote operation of cross-sectional imaging devices as a new form of teleoperation: Structural, technical, regulatory, and qualification aspects in Germany.

BACKGROUND: There is a significant shortage of radiographers in Germany and this shortage is expected to increase. Thus, it is becoming increasingly difficult for radiological facilities to adequately provide their services for the required period of time. Teleradiology has already been established for electronic transmission of diagnostic radiographic imaging examinations between two geographical locations for diagnostic reporting. Recently, the concept of teleoperating radiological devices has become increasingly attractive. METHOD: We examined the potential of teleoperating magnetic resonance imaging (MRI) in radiological facilities within the German regulatory framework in order to address the shortage of qualified personnel. To this end, we are introducing the concept of remote scanning, the structural foundations, the technical requirements associated with it, as well as the legal and educational qualifications of the relevant professional groups. Furthermore, suggestions regarding nomenclature and necessary standard operating procedures to efficiently integrate teleoperation into a clinical workflow adhering to high patient safety standards are provided. RESULTS: Companies provide technical solutions or even experienced radiographers as a service on demand for teleoperating radiological imaging devices remotely from a distance. There should be a comprehensive on-site strategy to effectively embed remote scanning into clinics. Local information technology and data security institutions should be involved in implementation. In order to guarantee that the remote operation workflow is able to provide health care services in line with regulative and legal standards, it is essential to implement standardized personal and institutional training, certifications, and accreditation procedures. Standard operating procedures (SOPs) and checklists for the involved staff, which are adapted to the local workflow in the participating facilities, are beneficial. CONCLUSION: Remote MRI scanning is an evolving technology that further expands the concept of teleradiology to include teleoperations and provides flexibility with respect to the staffing of MRI operators. Careful consideration and dedicated expertise of all involved parties are required to ensure patient safety, meet regulations, and successfully integrate teleoperations into clinics. KEY POINTS: · Remote MRI scanning expands the concept of teleradiology.. · Remote scanning provides flexibility regarding the staffing of MRI operators.. · IT and data security institutions should be involved when implementing remote scanning.. · Comprehensible SOPs and checklists should be established for remote MRI scanning.. · Radiation protection legislation does not allow purely remote CT scanning..