Microsurgical central lymphatic reconstruction-the role of thoracic duct lymphovenous anastomoses at different anatomical levels.

Introduction: In recent years advances have been made in the microsurgical treatment of congenital or acquired central lymphatic lesions. While acquired lesions can result from any surgery or trauma of the central lymphatic system, congenital lymphatic lesions can have a variety of manifestations, ranging from singular thoracic duct abnormalities to complex multifocal malformations. Both conditions may cause recurrent chylous effusions and downstream lymphatic congestion depending on the anatomical location of the thoracic duct lesion and are associated with an increased mortality due to the permanent loss of protein and fluid. Methods: We present a case series of eleven patients undergoing central lymphatic reconstruction, consisting of one patient with a cervical iatrogenic thoracic duct lesion and eleven patients with different congenital thoracic duct lesions or thrombotic occlusions. Results: Anastomosis of the thoracic duct and a nearby vein was performed on different anatomical levels depending on the underlying central lymphatic pathology. Cervical (n = 4), thoracic (n = 1) or abdominal access (n = 5) was used for central lymphatic reconstruction with promising results. In 9 patients a postoperative benefit with varying degrees of symptom regression was reported. Conclusion: The presented case series illustrates the current rapid advances in the field of central microsurgical reconstruction of lymphatic lesions alongside the relevant literature.

First-in-human Use of a Microsurgical Robotic System for Central Lymphatic Reconstruction.

Advances in the development of robotic systems have recently enabled the use of robotic technology in reconstructive lymphatic surgery. Although the advantages of microsurgical robots must be weighed carefully against the costs, their use may allow for smaller surgical approaches and easier access to anatomically deeper structures or even smaller vessels. We report on a case of a patient with central lymphatic dilation causing abdominal pain and severely reduced physical capacity. Sonography-assisted intranodal injection of indocyanine green allowed for localization of the lymphatic cyst and anastomosis with the left ovarian vein, applying robotic-assisted microsurgery for the first time on the central lymphatic system. Following the successful reconstruction of lymphatic drainage and decompression of the cyst, the patient reported a complete regression of her preoperative symptoms. From a surgical point of view, the Symani Surgical System improved precision and allowed significantly smaller surgical access. Considering the high morbidity and rarity of pathologies of the central lymphatic system, central lymphatic surgery is to date rarely performed. With improved precision and significantly smaller surgical access, robotic-assisted microsurgery has great potential to expand the treatment options for central lymphatic lesions.

Long-term patency of arteriovenous fistulas for hemodialysis: A decade's experience in a transplant unit.

BACKGROUND: The heterogeneous quality of studies on arteriovenous fistulas outcome, with variable clinical settings and large variations in definitions of patency and failure rates, leads to frequent misinterpretations and overestimation of arteriovenous fistula patency. Hence, this study aimed to provide realistic and clinically relevant long-term arteriovenous fistula outcomes. METHODS: We retrospectively analyzed all autologous arteriovenous fistulas at our center over a 10-year period (2012-2022). Primary and secondary patency analysis was conducted using the Kaplan-Meier method; multivariate analysis of variance was used to detect outcome predictors. Vascular access-specific endpoints were defined according to the European guidelines on vascular access formation. FINDINGS: Of 312 arteriovenous fistulas, 57.5% (n = 181) were radio-cephalic (RC_AVF), 35.2% (n = 111) brachio-cephalic (BC_AVF), and 6.3% (n = 20) brachio-basilic (BB_AVF). 6, 12, and 24 months follow-up was available in 290 (92.1%), 282 (89.5%), and 259 (82.2%) patients, respectively. Primary patency rates at 6, 12, and 24 months were 39.5%, 34.8%, and 27.2% for RC_AVF, 58.3%, 44.4%, and 27.8% for BC_AVF, and 40.0%, 42.1%, and 22.2% for BB_AVF (p = 0.15). Secondary patency rates at 6, 12, and 24 months were 65.7%, 63.8%, and 59.0% for RC_AVF, 77.7%, 72.0%, and 59.6% for BC_AVF, and 65.0%, 68.4%, and 61.1% for BB_AVF (p = 0.29). Factors associated with lower primary and secondary patency were hemodialysis at time of arteriovenous fistula formation (p = 0.037 and p = 0.024, respectively) and higher Charlson Comorbidity Index (p = 0.036 and p < 0.001, respectively). Previous kidney transplant showed inferior primary patency (p = 0.005); higher age inferior secondary patency (p < 0.001). DISCUSSION: Vascular access care remains challenging and salvage interventions are often needed to achieve maturation or maintain patency. Strict adherence to standardized outcome reporting in vascular access surgery paints a more realistic picture of arteriovenous fistula patency and enables reliable intercenter comparison.

Photon-Counting Detector CT Angiography for Endoleak Detection After Endovascular Aortic Repair: Triphasic CT With True Noncontrast Versus Biphasic CT With Virtual Noniodine Imaging.

OBJECTIVES: The aim of this study was to compare image quality and endoleak detection after endovascular abdominal aortic aneurysm repair between a triphasic computed tomography (CT) with true noncontrast (TNC) and a biphasic CT with virtual noniodine (VNI) images on photon-counting detector CT (PCD-CT). MATERIALS AND METHODS: Adult patients after endovascular abdominal aortic aneurysm repair who received a triphasic examination (TNC, arterial, venous phase) on a PCD-CT between August 2021 and July 2022 were retrospectively included. Endoleak detection was evaluated by 2 blinded radiologists on 2 different readout sets (triphasic CT with TNC-arterial-venous vs biphasic CT with VNI-arterial-venous). Virtual noniodine images were reconstructed from the venous phase. The radiologic report with additional confirmation by an expert reader served as reference standard for endoleak presence. Sensitivity, specificity, and interreader agreement (Krippendorf α) were calculated. Image noise was assessed subjectively in patients using a 5-point scale and objectively calculating the noise power spectrum in a phantom. RESULTS: One hundred ten patients (7 women; age, 76 ± 8 years) with 41 endoleaks were included. Endoleak detection was comparable between both readout sets with a sensitivity and specificity of 0.95/0.84 (TNC) versus 0.95/0.86 (VNI) for reader 1 and 0.88/0.98 (TNC) versus 0.88/0.94 (VNI) for reader 2. Interreader agreement for endoleak detection was substantial (TNC: 0.716, VNI: 0.756). Subjective image noise was comparable between TNC and VNI (4; IQR [4, 5] vs 4; IQR [4, 5], P = 0.44). In the phantom, noise power spectrum peak spatial frequency was similar between TNC and VNI (both f peak = 0.16 mm -1 ). Objective image noise was higher in TNC (12.7 HU) as compared with VNI (11.5 HU). CONCLUSIONS: Endoleak detection and image quality were comparable using VNI images in biphasic CT as compared with TNC images in triphasic CT offering the possibility to reduce scan phases and radiation exposure.

Determinants of Advanced Liver Fibrosis in Adult Patients After Fontan Palliation: Usefulness of Ultrasound Transient Elastography.

BACKGROUND: Fontan-associated liver disease is an increasing concern. Our aim was to assess prevalence and predictors of advanced liver fibrosis with a specific focus on utility of liver stiffness measurement by ultrasound transient elastography. METHODS: A total of 97 adult Fontan patients (55% male, median age: 23.1 years, interquartile range [IQR]: 18.7-30.6); 92 (95%) were evaluated with transient elastography, and 50 (52%) underwent transjugular liver biopsy. Advanced liver fibrosis was defined as congestive hepatic fibrosis score 3 or 4. RESULTS: Only 4 patients (4%) had liver stiffness values < 10 kilopascal (kPa). Liver-stiffness measurements correlated weakly with peak oxygen uptake on exercise testing and Fontan pressure but not with Model for End-Stage Liver Disease excluding INR (MELD-XI) score or spleen size. Serial follow-up liver stiffness measurements in 73 clinically stable patients showed large variability among individual patients. Advanced liver fibrosis was present in 35 of 50 (70%) patients on liver biopsy and was associated to MELD-XI-Score ≥ 11 and splenomegaly but not to liver-stiffness measurements. Advanced liver fibrosis was not associated with patient age or time since Fontan operation but with younger age at completion of Fontan (3.7 years, IQR: 2.3-6.3 vs 6.8 years; IQR: 3.5-12.1; P = 0.037). CONCLUSIONS: In our cohort, advanced liver fibrosis was present in the majority of adult Fontan patients. Liver stiffness as measured by transient elastography was not associated with the degree of liver fibrosis. Because of its high variability on serial measurements, it seems not to be useful for clinical decision making. The unexpected finding that younger age at completion of Fontan was associated with advanced liver fibrosis merits further evaluation.

Atypical patterns of spinal segment degeneration in patients with abdominal aortic aneurysms.

PURPOSE: Abdominal aortic aneurysms (AAAs) affect the vascular perfusion of the lumbar spine. The treatment of AAAs with endovascular aortic aneurysm repair (EVAR) completely occludes the direct vascular supply to the lumbar spine. We hypothesized that patients with AAA who undergo EVAR show a different pattern of spinal degeneration than individuals without AAA. METHODS: In this retrospective institutional review board-approved study, 100 randomly selected patients with AAA who underwent EVAR with computed tomography (CT) scans between 2005 and 2017 were compared with age- and gender-matched controls without AAA. In addition, long-term follow-up CT images (> 6 months before EVAR, at the time of EVAR, and > 12 months after EVAR) of the patients were analysed to compare the progression of degeneration from before to after EVAR. Degeneration scores, lumbar levels with the most severe degeneration, and lumbar levels with progressive degeneration were analysed in all CT images. Fisher's exact test, Wilcoxon signed-rank test, and Mann-Whitney U test were performed for statistical analyses. RESULTS: Compared with the control group (n = 94), the most severe degeneration was more commonly detected in the mid-lumbar area in the patient group (n = 100, p = 0.016), with significantly more endplate erosions being detected in the lumbar spine (p = 0.015). However, EVAR did not result in significant additional acceleration of the degenerative process in the long-term follow-up analysis (n = 51). CONCLUSION: AAA is associated with atypical, more cranially located spinal degradation, particularly in the mid-lumbar segments; however, EVAR does not seem to additionally accelerate the degenerative process. This observation underlines the importance of disc and endplate vascularization in the pathomechanism of spinal degeneration. LEVEL OF EVIDENCE I: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Quantitative and qualitative evaluation of liver metastases with intraprocedural cone beam CT prior to transarterial radioembolization as a predictor of treatment response.

Purpose: To investigate, by quantitative and qualitative enhancement measurements, the correlation between tumor enhancement on cone beam computed tomography (CBCT) images and treatment response at 6 months in patients undergoing transarterial radioembolization (TARE) for liver metastases. Materials and Methods: 36 patients (56% male; median age 62.5 years) with 104 metastases were retrospectively included. Quantitative and qualitative enhancement of liver metastases were evaluated on CBCT images before TARE. Quantitative analysis consisted of lesion enhancement measurements (ROI HU lesion - ROI HU relative to inferior vena cava). Qualitative analysis consisted of subjective enhancement pattern analysis (diffuse, sparse, rim-like or non-enhancing). Morphologic tumor response was evaluated according to RECIST 1.1 criteria on follow-up CT or MR imaging. Results: At a mean follow up of 6.5 ± 3.7 months, progressive disease (PD) was found in 4 patients, partial response (PR) in 11 and stable disease (SD) in 21. Relative lesion enhancement was significantly different between these groups (-37.5±154.2 HU vs. 103.8±93.4 vs. 181±144 HU in PD vs. SD vs. PR group, respectively; p<0.01). ROC analysis of relative lesion enhancement to predict progressive disease showed an area under the curve of 0.86 (p<0.01). For qualitative lesion enhancement analysis, no difference between groups was found. Conclusion: Quantitative enhancement measurements derived from intraprocedural contrast enhanced CBCT may identify responders to TARE in patients with liver metastases.

Prediction of treatment response to transarterial radioembolization of liver metastases: Radiomics analysis of pre-treatment cone-beam CT: A proof of concept study.

PURPOSE: To investigate the potential of texture analysis and machine learning to predict treatment response to transarterial radioembolization (TARE) on pre-interventional cone-beam computed tomography (CBCT) images in patients with liver metastases. MATERIALS AND METHODS: In this IRB-approved retrospective single-center study 36 patients with a total of 104 liver metastases (56 % male, mean age 61.1 ± 13 years) underwent CBCT prior to TARE and follow-up imaging 6 months after therapy. Treatment response was evaluated according to RECIST version 1.1 and dichotomized into disease control (partial response/stable disease) versus disease progression (progressive disease). After target lesion segmentation, 104 radiomics features corresponding to seven different feature classes were extracted with the pyRadiomics package. After dimension reduction machine learning classifications were performed on a custom artificial neural network (ANN). Ten-fold cross validation on a previously unseen test data set was performed. RESULTS: The average administered cumulative activity from TARE was 1.6 Gbq (± 0.5 Gbq). At a mean follow-up of 5.9 ± 0.8 months disease control was achieved in 82 % of metastases. After dimension reduction, 15 of 104 (15 %) texture analysis features remained for further analysis. On a previously unseen set of liver metastases the Multilayer Perceptron ANN yielded a sensitivity of 94.2 %, specificity of 67.7 % and an area-under-the receiver operating characteristics curve of 0.85. CONCLUSION: Our study indicates that texture analysis-based machine learning may has potential to predict treatment response to TARE using pre-treatment CBCT images of patients with liver metastases with high accuracy.

Recanalization of Chronic Noncirrhotic, Nonmalignant Splanchnic Thromboses is Feasible: A Transsplenic Assisted Patient-Tailored Approach.

The purpose of this study was to evaluate the feasibility of recanalization of chronic noncirrhotic, nonmalignant splanchnic thromboses with a transsplenic assisted patient-tailored approach with or without transjugular intrahepatic portosystemic shunt (TIPS) creation. In this retrospective study, 10 patients (median age, 48.4 years; interquartile range, 5.1 years) underwent revascularization between November 2016 and August 2020. Portal cavernoma was present in all patients, with complete splenic vein thrombosis in 70%. The technical success rate was 80%. Additional TIPS creation was performed in 5 (50%) patients. At a median follow-up of 19.3 months (interquartile range, 17.9 months), the primary and secondary patency rate was 70% and 100%, respectively. During follow-up, 1 patient died due to recurrent upper gastrointestinal variceal hemorrhage. In conclusion, percutaneous transsplenic assisted recanalization of chronic noncirrhotic, nonmalignant splanchnic thromboses is feasible. However, multiple access points may still be needed. Additional TIPS creation appears to be necessary only in case of insufficient portal venous flow into the liver.

Fusion of Preinterventional MR Imaging With Liver Perfusion CT After RFA of Hepatocellular Carcinoma: Early Quantitative Prediction of Local Recurrence.

OBJECTIVES: The aim of this study was to evaluate the ability of fusion of pretreatment magnetic resonance (MR) imaging with posttreatment perfusion-CT (P-CT) after radiofrequency ablation (RFA) of hepatocellular carcinomas (HCCs) and to determine treatment success in an objective, quantitative way. MATERIALS AND METHODS: In this institutional review board-approved study, 39 patients (78.4% male; mean age 68.2 ± 8.5 years) with a total of 43 HCCs, who underwent RFA at our institution and had diagnostic pre-RFA MR imaging and post-RFA P-CT, were included in the study. Post-RFA P-CT was performed within 24 hours after RFA. In a first step, the pre-RFA MR imaging, depicting the HCC, was registered onto the post-RFA P-CT using nonrigid image registration. After image registration, the MR data were reloaded jointly with the calculated perfusion parameter volumes into the perfusion application for quantitative analysis. A 3-dimensional volume of interest was drawn around the HCC and the ablation zone; both outlines were automatically projected onto all perfusion maps. Resulting perfusion values (normalized peak enhancement [NPE, %]; arterial liver perfusion [ALP, in mL/min/100 mL]; BF [blood flow, mL/100 mL/min]; and blood volume [BV, mL/100 mL]) and histogram data were recorded. Local tumor recurrence was defined in follow-up imaging according to the EASL guidelines. RESULTS: Image registration of MR imaging and CT data was successful in 37 patients (94.9%). Local tumor recurrence was observed in 5 HCCs (12%). In the local tumor recurrence group (LTR-group), HCC size was significantly larger (22.7 ± 3.9 cm vs 17.8 ± 5.3 cm, P = 0.035) and the ablation zone was significantly smaller (29.8 ± 6.9 cm vs 39.3 ± 6.8 cm, P = 0.014) compared with the no-local tumor recurrence group (no-LTR group). The differences (ablation zone - tumor) of the perfusion parameters NPE, ALP, BF, and BV significantly differed between the 2 groups (all P's < 0.005). Especially, the difference (ablation zone - tumor) of NPE and ALP, with a cutoff value of zero, accurately differentiated between LTR or no-LTR in all cases. A negative difference of these perfusion parameters identified local tumor recurrence in all cases. CONCLUSIONS: Image registration of pre-RFA MR imaging onto post-RFA P-CT is feasible and allows to predict local tumor recurrence within 24 hours after RFA in an objective, quantitative manner and with excellent accuracy.

Outpatient Yttrium-90 microsphere radioembolization: assessment of radiation safety and quantification of post-treatment adverse events causing hospitalization.

PURPOSE: Quantification of post-interventional adverse events of outpatient SIRT leading to hospitalization and quantification of radiation exposure. MATERIALS AND METHODS: In this single-center, retrospective cohort study, we reviewed 212 patients treated with SIRT (90Y-microspheres) for primary and secondary liver malignancies. We searched for adverse events (AEs) and serious adverse events (SAEs), defined as AE's causing hospitalization. Additionally, radiation exposure was measured in 36 patients. RESULTS: Seven patients had an SAE (3.3%), four patients had AE without readmission/hospitalization (1.9%) and 201 patients had no complications (94.8%). The mean ambient dose rate at 1 m distance from the source after administration of 90Y-microspheres was 1.88 µSv/h ± 0.74 (± SD) with a range from 4.3 to 0.2 µSv/h. CONCLUSION: Outpatient radioembolization with 90Y-microspheres is safe and requires hospitalization only in a very small number of patients. The mean dose rate was low and met the national conditions for outpatient treatment (< 5 µSv/h).

Frequency and causes of delayed diagnosis of visceral artery pseudoaneurysms with CT: Lessons learned.

OBJECTIVE: Visceral artery pseudoaneurysms (VAPA) are associated with a high morbidity and mortality, but sometimes are missed in initial computed tomography (CT) examinations. The aims of this study were to determine the frequency and causes of misdiagnoses of VAPA with CT. MATERIALS AND METHODS: We retrospectively identified 77 patients with VAPA in our database who underwent contrast-enhanced CT. The frequency of delayed diagnosis was determined and the reasons were noted. We identified the etiology of VAPA, measured size, and noted the affected vessels. RESULTS: Forty-five of the 77 patients (58 %) had a delayed diagnosis of VAPA. There was no difference in the rate of missed VAPA in symptomatic compared to asymptomatic patients (p = 0.255). The majority of VAPA were associated with previous surgery or interventions (n = 48/62 %). The major affected vessel was the hepatic (n = 31) followed by the splenic artery (n = 17). The main reasons for misdiagnosis were a missed arterial phase in CT (n = 16/36 %), artifacts masking the aneurysm (n = 9/20 %), overlooked pseudoaneurysm (n = 19/42 %), and misinterpretation by attending radiologists (n = 1/2 %). Missed VAPA were smaller (median 8 mm) than those VAPA that were initially diagnosed (median 13 mm, p < 0.01), but occurred with a similar frequency in larger and smaller visceral arteries (p = 0.601). CONCLUSIONS: Our study showed that 58 % of VAPA were diagnosed with delay, with the following four reasons for misdiagnosis: Lack of an arterial contrast phase in CT, no techniques for artifact reduction, and lack of awareness of the radiologists. Avoiding delayed diagnosis will most probably improve outcome of patients with VAPA.

Sclerotherapy With OK-432 for the Treatment of Symptomatic Lymphocele After Lymph Node Dissection: A Retrospective Comparative Cohort Study.

OBJECTIVE: This study aimed to determine the benefits of sclerotherapy with OK-432 for the treatment of postoperative chronic lymphocele. BACKGROUND: Postoperative chronic lymphocele formation is common and accounts for a high postoperative morbidity. Nonsurgical strategies comprise repetitive percutaneous fluid aspiration or percutaneous sclerotherapy. OK-432 has been used to treat congenital lymphatic malformations with several reports of promising results. We hypothesized that it is more beneficial than repetitive percutaneous fluid aspiration for the treatment of symptomatic lymphocele. METHODS: Two cohorts of melanoma patients who developed recurrent lymphocele after lymph node dissection from January 2013 to August 2017 were compared. The first cohort was treated with repetitive percutaneous fluid aspiration (n = 20). The second cohort received OK-432 sclerotherapy (n = 20). Primary end points were overall treatment duration, number of treatment sessions, and the clinical success in both cohorts. Secondary end points were surgical site infection rate, need for additional antibiotic treatment, wound healing disorders, and the need for revision surgery. RESULTS: Mean overall duration of treatment with sclerotherapy was significantly shorter than with repetitive aspiration (9.4 ± 7.2 vs 47.5 ± 31.9 days, P < 0.01). Mean number of sclerotherapy treatment sessions were 2.5 ± 1.2. Clinical success with OK-432 was 19 of 20, and that with repeated aspiration was 7 of 20 (χ = 15.82, P < 0.001). No surgical site infection occurred in the sclerotherapy cohort, which was significantly lower than those treated with repetitive aspiration (P < 0.03). Surgical revision was mandatory in 12 of 20 patients who were treated with repetitive aspiration, and only 1 of 20 patients in the sclerotherapy cohort. CONCLUSION: Sclerotherapy with OK-432 for the treatment of postoperative lymphocele is highly beneficial with a significant reduction of morbidity and the overall treatment time compared with repetitive aspiration.

Lymphovenous Anastomosis for the Treatment of Thoracic Duct Lesion: A Case Report and Systematic Review of Literature.

BACKGROUND: Chylous leak is an uncommon complication after head and neck surgery and typically results from a lesion of the thoracic duct (TD). Beside conservative treatment, different minimally invasive and surgical procedures exist, of which almost all lead to a total closure of the TD. METHODS: We report on a rare case of microsurgical lymphovenous anastomosis to treat a TD lesion. An additional systematic review on surgical procedures to treat TD lesions with special attention to lymphovenous anastomoses was performed according to the PRISMA guidelines. RESULTS: A 52-year-old patient with a chylous fistula after modified radical neck dissection was successfully treated by a lymphovenous anastomosis of the TD and external jugular vein with additional coverage by sternocleidomastoid muscle flap. The patient showed a complete resolution of chylous leak with an uneventful postoperative course.The systematic search of literature yielded 684 articles with 4 case reports on lymphovenous anastomosis in chylous leak with a high success rate. Other surgical techniques include transcervical, thoracoscopic, or video-assisted thoracoscopic TD ligation, either alone or combined with a local muscle flap. CONCLUSIONS: Lymphovenous anastomosis of the TD is a feasible and safe technique allowing for treatment of cervical TD lesions, especially if minimally invasive procedures fail. Compared with other techniques, lymphatic circulation can successfully be maintained.

Computed Tomography for 4-Dimensional Angiography and Perfusion Imaging of the Prostate for Embolization Planning of Benign Prostatic Hyperplasia.

OBJECTIVES: The aim of this study was to evaluate the feasibility of a computed tomography (CT) protocol enabling the visualization of the prostatic artery (PA) before prostatic artery embolization (PAE) in benign prostatic hyperplasia, which provides quantitative perfusion information of the prostate gland. MATERIALS AND METHODS: In this institutional review board-approved study, 22 consecutive patients (mean age, 67 ± 7 years) who were planned to undergo PAE underwent a dynamic CT scan of the pelvis (scan range, 22.4 cm; cycle time, 1.5 seconds; scan time, 44 seconds; 25 scan cycles; 70 kVp; 100 mAs) after the administration of 70 mL of iodinated contrast media (flow rate, 6 mL/s; 10 seconds' delay). Image postprocessing consisted of a spatiotemporal, frequency-depending multiband filtering technique with noise reduction, motion correction, resulting in (1) time-resolved, temporal maximum intensity projection (MIP) images from fusion of multiple arterial time points; (2) 4-dimensional (4D) CT angiography images after bone and calcium plaque removal; and (3) parametric perfusion maps of the prostate. Intraprocedural cone-beam CT was performed with a microcatheter in the PA. In both modalities, the contrast-to-noise ratio of the right internal iliac artery or the PA was calculated, respectively. Visibility of the PA was scored using a Likert scale (score 1 = not seen, to score 4 = intraprostatic PA branches seen). Quantitative perfusion analysis of the dynamic pelvic CT included calculation of the blood flow, blood volume, mean transit time, and flow extraction product. RESULTS: The average volume CT dose index and dose length product of CT was 35.7 ± 6.8 mGy and 737.4 ± 146.3 mGy·cm, respectively. Contrast-to-noise ratio of the pelvic vessels on temporal MIP images and cone-beam CT were 45 ± 19 and 69 ± 27, respectively (P < 0.01). The mean visibility score of the PA was 3.6 ± 0.6 for 4D-CT angiography and 3.97 ± 0.2 for cone-beam CT (P < 0.001). The PA was visualized in 100% of 4D-CT angiography examinations, with one PA being visible only proximally. Prostate CT perfusion analysis showed blood flow, blood volume, mean transit time, and flow extraction product values of 27.9 ± 12.5 mL/100 mL/min, 2.0 ± 0.8 mL/100 mL, 4.5 ± 0.5 second, and 12.6 ± 5.4 mL/100 mL/min, respectively, for the whole prostate gland. About half the patients showed a pronounced difference between the lobes. CONCLUSIONS: We introduced a CT protocol for PAE planning providing excellent visualization of the PA on temporal MIP images and 4D-CT angiography at a reasonable dose and low contrast volume. In addition, quantitative perfusion information is available, which might be useful for outcome prediction after embolization.

Primary Endovascular Elective Repair and Repair of Ruptured Isolated Iliac Artery Aneurysms Is Durable-Results of 72 Consecutive Patients.

PURPOSE: To evaluate outcome of endovascular elective repair and repair of ruptured isolated iliac artery aneurysms (IIAAs) as a primary treatment strategy. MATERIALS AND METHODS: All patients with an IIAA undergoing endovascular treatment were included. Aneurysms were classified according to an anatomic classification and treated with coiling of the internal iliac artery, stent graft placement in the common to external iliac artery, or placement of a bifurcated aortoiliac stent graft. Between November 1996 and November 2015, 72 patients with 85 IIAAs underwent endovascular repair. Mean age was 73.9 years ± 9.2. Common iliac artery was involved in 63 patients (74.1%), internal iliac artery was involved in 21 patients (24.7%), and external iliac artery was involved in 1 patient (1.2%). Mean diameter was 5 cm (range, 2.5-11 cm). Emergency repair was performed in 19 patients owing to rupture (26.4%). RESULTS: Overall primary technical success rate was 95.8% with conversion rate to open surgery of 4.2% (all in the emergency group) and in-hospital mortality rate of 1.4%. During mean follow-up of 4.3 years ± 3.3 (median 3.8 y; range, 0-14.2 y), 17 endoleaks were observed (6 type I, 10 type II, 1 type IIIa). Overall reintervention rate was 16.7%. Primary patency rate was 98.6%. During the follow-up period, 22 deaths occurred (30.6%), including 2 aneurysm-related deaths (2.8%). CONCLUSIONS: Primary endovascular repair of IIAAs shows excellent results and should be considered as first-line therapy. Surgical backup should be available in emergency cases.

Early outcomes with a single-sided access endovascular stent.

OBJECTIVE: The objective of this study was to report the 1-year follow-up study results of the new Horizon stent graft (Endospan, Herzliya, Israel) from two different prospective consecutive trials. The Horizon abdominal aortic aneurysm stent graft system is a 14F profile system requiring only a single access site. It consists of three modules, introduced separately: base limb (iliac to iliac limb); distal aortic limb; and proximal aortic limb with a bare suprarenal crown and active fixation. METHODS: Data from the first in man (FIM) clinical study with 10 patients enrolled and the pivotal study with 30 patients were analyzed. Outcomes measured were freedom from major adverse events (MAEs) including all-cause mortality, myocardial infarction, renal failure, respiratory failure, paraplegia, stroke, bowel ischemia, and procedural blood loss ≥1000 mL. Performance end points included successful delivery and deployment of the device, freedom from aneurysm growth ≥5 mm, type I or type III endoleak, stent graft occlusion, conversion to open surgery, rupture, and stent graft migration. RESULTS: In the FIM study, one conversion to open surgery with >1000 mL of blood loss was registered perioperatively. In the pivotal study, no perioperative MAE was registered. Overall, at 1-year follow-up, two deaths and one aneurysm growth unrelated to endoleak were registered. CONCLUSIONS: The results of both the FIM and pivotal studies demonstrated that 39 of 40 procedures were successful for delivery and deployment of the Horizon stent graft. No MAE was registered during the follow-up. The primary safety and performance end points were met in both studies.

Prototype metal artefact reduction algorithm in flat panel computed tomography - evaluation in patients undergoing transarterial hepatic radioembolisation.

OBJECTIVE: To investigate the effect of an on-site prototype metal artefact reduction (MAR) algorithm in cone-beam CT-catheter-arteriography (CBCT-CA) in patients undergoing transarterial radioembolisation (RE) of hepatic masses. METHODS AND MATERIALS: Ethical board approved retrospective study of 29 patients (mean 63.7±13.7 years, 11 female), including 16 patients with arterial metallic coils, undergoing CBCT-CA (8s scan, 200 degrees rotation, 397 projections). Image reconstructions with and without prototype MAR algorithm were evaluated quantitatively (streak-artefact attenuation changes) and qualitatively (visibility of hepatic parenchyma and vessels) in near- (<1cm) and far-field (>3cm) of artefact sources (metallic coils and catheters). Quantitative and qualitative measurements of uncorrected and MAR corrected images and different artefact sources were compared RESULTS: Quantitative evaluation showed significant reduction of near- and far-field streak-artefacts with MAR for both artefact sources (p<0.001), while remaining stable for unaffected organs (all p>0.05). Inhomogeneities of attenuation values were significantly higher for metallic coils compared to catheters (p<0.001) and decreased significantly for both after MAR (p<0.001). Qualitative image scores were significantly improved after MAR (all p<0.003) with by trend higher artefact degrees for metallic coils compared to catheters. CONCLUSION: In patients undergoing CBCT-CA for transarterial RE, prototype MAR algorithm improves image quality in proximity of metallic coil and catheter artefacts. KEY POINTS: • Metal objects cause artefacts in cone-beam computed tomography (CBCT) imaging. • These artefacts can be corrected by metal artefact reduction (MAR) algorithms. • Corrected images show significantly better visibility of nearby hepatic vessels and tissue. • Better visibility may facilitate image interpretation, save time and radiation exposure.

Ultrasound Needle Visibility in Contrast Mode Imaging: An In Vitro and Ex Vivo Study.

PURPOSE: To evaluate needle visibility in ultrasound under contrast mode conditions. MATERIALS AND METHODS: Needle visibility was evaluated for bevel, EchoTip ® and shaft of 18G Chiba biopsy needle with a 9 MHz linear probe (GE Logiq E9). Insertion angles varied between 30°(steep) and 90°(parallel to the probe surface). The acoustic output varied from 5-28%. 2 different contrast mode presets with either 'Amplitude Modulation' (Penetration) or 'Phase Inversion Harmonics' (High Resolution) were assessed. All other imaging parameters were kept constant. The visibility of bevel, EchoTip ® and shaft was assessed for grayscale and color-coded images with a 3-point Likert-like scale (not, poorly, well visible) by 2 independent readers. The echogenicity of the needle bevel, EchoTip ® and shaft was assessed in deciBel (dB) on the color-coded images. RESULTS: With the parallel insertion angle, all needle areas were well visible. With steep insertion the EchoTip ® was the only visible area. High Resolution was superior to Penetration (p<0.001). The visibility and echogenicity of the needle bevel ( rgrayscale =0.109, p grayscale =0.178; rcolor-coded =0.236, p color-coded =0.266; rdB =0.956, p dB =0.001), EchoTip ® ( rgrayscale += 0.477, p grayscale += 0.018; rcolor-coded =0.540, p color-coded += 0.006; rdB =0.911, p dB =0.001) and shaft ( rgrayscale =0.124, p grayscale =0.563; rcolor-coded =0.061, p color-coded += 0.775; rdB += 0.926, p dB =0.001) increased with increasing acoustic output. Grayscale images were superior to color-coded images for needle visibility (p=0.004). CONCLUSION: Parallel needle insertion, use of an echogenic tip, adequate choice of presets, increased acoustic output, and dual view of grayscale and color-coded images improve needle visibility in ultrasound under contrast mode conditions.