FLOW: Flow dysfunction of hemodialysis vascular access: A randomized controlled trial on the effectiveness of surveillance of arteriovenous fistulas and grafts.

INTRODUCTION: It is assumed that identification and correction of asymptomatic stenoses in the vascular access circuit will prevent thrombosis that would require urgent intervention to continue hemodialysis treatment. However, the evidence base for this assumption is limited. Recent international clinical practice guidelines reach different conclusions on the use of surveillance for vascular access flow dysfunction and recommend further research to inform clinical practice. METHODS: The FLOW trial is a double-blind, multicenter, randomized controlled trial with a 1:1 individual participant treatment allocation ratio over two study arms. In the intervention group, only symptomatic vascular access stenoses detected by clinical monitoring are treated, whereas in the comparison group asymptomatic stenoses detected by surveillance using monthly dilution flow measurements are treated as well. Hemodialysis patients with a functional arteriovenous vascular access are enrolled. The primary outcome is the access-related intervention rate that will be analyzed using a general linear model with Poisson distribution. Secondary outcomes include patient satisfaction, access-related serious adverse events, and quality of the surveillance process. A cost effectiveness analysis and budget impact analysis will also be conducted. The study requires 828 patient-years of follow-up in 417 participants to detect a difference of 0.25 access-related interventions per year between study groups. DISCUSSION: As one of the largest randomized controlled trials assessing the clinical impact of vascular access surveillance using a strong double-blinded study design, we believe the FLOW trial will provide much-needed evidence to improve vascular access care for hemodialysis patients.

12Fr-Pigtail Versus 14Fr-Balloon Percutaneous Radiologic Gastrostomy (PRG), Retrospective Evaluation of Outcomes and Complications; A Maastricht University Medical Centre Study.

PURPOSE: To retrospectively compare tube and placement related results of a 12Fr-pigtail and a 14Fr-balloon gastrostomy tube. MATERIALS AND METHODS: All consecutive patients who underwent percutaneous radiologic gastrostomy (PRG) between January 2016 and June 2020 were enrolled in this retrospective single-center analysis. Follow-up for all patients was 180 days. Mortality after 30 days, technical success, days to first complication within 180 days, reason of unexpected visit (tube, anchor or pain related), and tube specific complications (obstruction, pain, luxation, leakage) were taken as outcome measures. Data were obtained from both PACS software and electronic health records. RESULTS: A total of 247 patients were enrolled (12Fr-pigtail: n = 139 patients and 14Fr-balloon: n = 108 patients). 30-day mortality was very low in both groups and never procedure related. Technical success was 99% in both groups. The average number of complications within 180 days after initial PRG placement was significantly higher in the 12Fr-pigtail group (12Fr-pigtail: 0.93 vs. 14Fr-balloon: 0.64, p = 0.028). Time to first complication within 180 days was significantly longer in the 14Fr-balloon group (12Fr-pigtail: 29 days vs. 14Fr-balloon: 53 days, p = 0.005). In the 14Fr-balloon group, the rate of tube-related complications (luxation and obstruction) was significantly lower compared to 12Fr-pigtail (29% vs. 45%, p = 0.011). CONCLUSION: 14Fr-balloon gastrostomy tubes have significantly lower (tube-related) complications rates and longer time to first complication compared to 12Fr-pigtail tubes. No procedure-related mortality was observed in either group. Technical success was very high in both groups. Level of Evidence Level 3, non-controlled retrospective cohort study.

Impact of stent-graft complexity on mid-term results in fenestrated endovascular aortic repair of juxtarenal and suprarenal abdominal aortic aneurysms.

BACKGROUND: The impact of stent-graft complexity on clinical outcome after fenestrated endovascular aortic aneurysm repair (FEVAR) has been conflicting in the literature. The objective of this study was to compare mid-term results of stent-grafts with renal fenestrations alone with more complex stent-grafts including mesenteric fenestrations. METHODS: A single center retrospective study was conducted on 154 patients, who underwent FEVAR from 2006 to 2020 at our institution. RESULTS: There were 54 (35.1%) patients in the renal FEVAR group and 100 (64.9%) patients in the complex FEVAR group. Median follow-up of the total group was 25 months (IQR 7-45). There were no significant differences in technical success and perioperative mortality. Intraoperative complications (4% vs. 18%, P=0.001), operative time (145 min vs. 191 min, P=0.001), radiation dose (119372 mGy*cm2 vs. 159573 mGy*cm2, P=0.004) and fluoroscopy time (39 min vs. 54 min, P=0.007) were significantly lower in the renal FEVAR group. During follow-up target vessel instability, endoleaks and reinterventions were not significantly different between the two groups. CONCLUSIONS: In this single center retrospective study, renal FEVAR was a safe and effective treatment for patients with juxtarenal AAA demonstrating fewer intraoperative complications and similar mid-term outcomes as complex FEVAR. If the anatomy is compatible for renal FEVAR, it might be unnecessary to expose patients to potentially more complications by choosing a complex FEVAR strategy.

Optimising Access Surgery in Senior Haemodialysis Patients (OASIS): study protocol for a multicentre randomised controlled trial.

INTRODUCTION: Current evidence on vascular access strategies for haemodialysis patients is based on observational studies that are at high risk of selection bias. For elderly patients, autologous arteriovenous fistulas that are typically created in usual care may not be the best option because a significant proportion of fistulas either fail to mature or remain unused. In addition, long-term complications associated with arteriovenous grafts and central venous catheters may be less relevant when considering the limited life expectancy of these patients. Therefore, we designed the Optimising Access Surgery in Senior Haemodialysis Patients (OASIS) trial to determine the best strategy for vascular access creation in elderly haemodialysis patients. METHODS AND ANALYSIS: OASIS is a multicentre randomised controlled trial with an equal participant allocation in three treatment arms. Patients aged 70 years or older who are expected to initiate haemodialysis treatment in the next 6 months or who have started haemodialysis urgently with a catheter will be enrolled. To detect and exclude patients with an unusually long life expectancy, we will use a previously published mortality prediction model after external validation. Participants allocated to the usual care arm will be treated according to current guidelines on vascular access creation and will undergo fistula creation. Participants allocated to one of the two intervention arms will undergo graft placement or catheter insertion. The primary outcome is the number of access-related interventions required for each patient-year of haemodialysis treatment. We will enrol 195 patients to have sufficient statistical power to detect an absolute decrease of 0.80 interventions per year. ETHICS AND DISSEMINATION: Because of clinical equipoise, we believe it is justified to randomly allocate elderly patients to the different vascular access strategies. The study was approved by an accredited medical ethics review committee. The results will be disseminated through peer-reviewed publications and will be implemented in clinical practice guidelines. TRIAL REGISTRATION NUMBER: NL7933. PROTOCOL VERSION AND DATE: V.5, 25 February 2021.

CIRSE Clinical Practice Manual.

BACKGROUND: Interventional radiology (IR) has come a long way to a nowadays UEMS-CESMA endorsed clinical specialty. Over the last decades IR became an essential part of modern medicine, delivering minimally invasive patient-focused care. PURPOSE: To provide principles for delivering high quality of care in IR. METHODS: Systematic description of clinical skills, principles of practice, organizational standards and infrastructure needed for the provision of professional IR services. RESULTS: There are IR procedures for almost all body parts and organs, covering a broad range of medical conditions. In many cases IR procedures are the mainstay of therapy, e.g. in the treatment of hepatocellular carcinoma. In parallel the specialty moved from the delivery of a procedure towards taking care for a patient's condition with the interventional radiologists taking ultimate responsibility for the patient's outcomes. CONCLUSIONS: The evolution from a technical specialty to a clinical specialty goes along with changing demands on how clinical care in IR is provided. The CIRSE Clinical Practice Manual provides interventional radiologist with a starting point for developing his or her IR practice as a clinician.

Percutaneous transhepatic portal vein stenting as rescue treatment for recurrent oesophageal variceal bleeding in a 31-year-old woman with haepatocellular carcinoma in a non-cirrhotic liver.

A 31-year-old woman with hepatocellular carcinoma suffered from recurrent oesophageal variceal bleeding due to portal hypertension, which was caused by severe compression of the portal vein by metastatic lymph nodes. Endoscopic band ligation and pharmacological treatment did not suffice to prevent recurrence of variceal bleeding. Eventually, after the fifth variceal bleeding within 6 months, the patient was admitted to the intensive care unit in a haemodynamic shock. A Sengstaken-Blakemore tube was inserted and all treatment options were discussed, but only percutaneous transhepatic recanalisation of the portal vein with stent placement to reduce portal vein pressure was thought to be feasible with any chance to relieve portal vein pressure. After successful portal vein stenting, our patient did not have any recurrent bleeding in the remaining year of her life. We suggest that percutaneous transhepatic portal vein stenting may be a feasible and adequate last line treatment for complications of portal hypertension.

Novel diagnostic and imaging techniques in endovascular iliac artery procedures.

INTRODUCTION: Endovascular revascularization has become the preferred treatment for most patients with iliac artery obstructions, with a high rate of clinical and technical success. AREAS COVERED: This review will describe novel developments in the diagnosis and treatment of iliac artery obstructions including the augmentation of preprocedural imaging with advanced flow models, image fusion techniques, and state-of-the-art device-tracking capabilities. EXPERT OPINION: The combination of these developments will change the endovascular field within the next 5 years, allowing targeted iliac treatment without the need for radiographic imaging or iodinated contrast media.

Stabilization of a steerable sheath during retrograde access to antegrade-oriented branches in complex endovascular aortic aneurysm repair.

During branched endovascular aneurysm repair, cannulation of the visceral target vessels through antegrade branches and insertion of bridging stents are frequently done from an upper extremity access. A retrograde femoral approach is a challenging alternative when an antegrade approach is not preferred. Herein, we describe a technique to increase stability of a steerable sheath, using a single suture, for bridging antegrade-facing branches from a retrograde access. This technique secures the sheath's deflected tip and provides more pushability to the steerable sheath.

Comparing Mobile C-Arm with a Hybrid Operating Room for Imaging in Fenestrated Stent-Graft Endovascular Abdominal Aortic Aneurysm Repair.

BACKGROUND: To evaluate the advantages of a hybrid operating room (OR) (group 2) compared with a fluoroscopic mobile C-arm (group 1) during fenestrated stent-graft endovascular aneurysm repair (f-EVAR). METHODS: This single-center study retrospectively analyzed prospectively collected data of consecutive patients treated with f-EVAR for short-necked, juxtarenal, and suprarenal aortic aneurysms between January 2006 and July 2016. Primary end points were technical success and perioperative complications. Secondary end points included 30-day and 1-year mortality as well as target vessel patency. RESULTS: About 96 patients were treated (85 men; 74.1 ± 6.3 years); 46 patients (48%) belonging to group 1 and 50 (52%) patients belonging to group 2. Technical success was achieved in 92.7% of the procedures (group 1 91.3% vs. group 2 94%, P = 0.72). Significantly more complex interventions were performed in group 2 (n = 38 of 50) compared with group 1 (n = 14 of 46; P < 0.001), in which primarily renal f-EVAR interventions were performed. In group 2, significantly less contrast was used (median 150 mL vs. 100 mL; P < 0.001). The 30-day mortality in group 1 was 9% and 2% in group 2 (P = 0.14), and 1-year survival was also not significantly different between both groups. Target visceral vessel primary patency was significantly higher in group 1 (87.6% vs. 85.5% [P = 0.006] and 83.8% vs. 78.3% [P = 0.03]) at 6 and 12 months, respectively). There was no significant difference in renal artery primary patency at 6 and 12 months. CONCLUSIONS: Immediate and 1-year outcomes after f-EVAR for abdominal aortic aneurysm were comparable using a hybrid OR compared with a mobile C-arm, despite the use of significantly more complex stent grafts in the patients treated in the hybrid OR. The use of a hybrid OR may assist in achieving satisfying results in complex f-EVAR.

Percutaneous endoscopic versus radiologic gastrostomy for enteral feeding: a retrospective analysis on outcomes and complications.

Background and study aims Percutaneous endoscopic gastrostomy (PEG) and percutaneous radiologic gastrostomy (PRG) are techniques used for long-term enteral feeding. Our primary aim was to analyze procedure-related and 30-day mortality and complications between PEG and PRG in relation to indications. Patients and methods A single-center retrospective analysis was performed thath included all adult patients receiving initial PEG (January 2008 until April 2016) and PRG (January 2010 until April 2016). Outcomes were mortality (procedure-related, 30-day), complications (early (≤ 30 days) and late) and success rates. Results A total of 760 procedures (469 PRG and 291 PEG) were analyzed. Most common indications were head and neck cancer (HNC), cerebrovascular accident (CVA) and amyotrophic lateral sclerosis (ALS). Success rates for placement were 91.2 % for PEG and 97.1 % for PRG ( P  = 0.001). Procedure-related mortality was 1.7 % in PEG and 0.4 % in PRG ( P  = 0.113). The 30-day mortality was 10.7 % in PEG and 5.1 % in PRG ( P  = 0.481 after multivariate logistic regression) CVA was associated with higher 30-day mortality, whereas ALS, higher body weight, and prophylactic placements in HNC were associated with lower rates. Tube-related complications were less frequent in PEG, both early (2.7 % vs. 26.4 %, P  ≤ 0.001) and late (8.6 % vs. 31.5 %, P  ≤ 0.001). The percentage of major complications and infections did not differ. Conclusions With respect to procedure-related and 30-day mortality, PEG and PRG compare equally. PRG had a higher procedural success rate. Tube-related complications and pain are less frequent after PEG compared to PRG. The choice for either PEG or PRG therefore should primarily be based on local facilities and expertise.

A Stopped Pilot Study of the ProGlide Closure Device After Transbrachial Endovascular Interventions.

Purpose: To evaluate the feasibility and safety of the suture-mediated ProGlide device in closure of the brachial artery after endovascular interventions. Materials and Methods: From 2016 to 2017, a pilot study was performed using the ProGlide to achieve hemostasis after percutaneous access of distal brachial arteries >4 mm in diameter. In an interim analysis, the results were compared to a matched control group taken from a 60-patient historical cohort who underwent brachial artery access and manual compression to achieve hemostasis between 2014 and 2017. The primary outcome was access-related reintervention and the secondary outcome was the incidence of access-site complications. Results: Seven patients (mean age 67.9 years; 6 men) were enrolled in the study before it was stopped in 2017. Four patients experienced 6 access-site complications (neuropathy, hematoma, occlusion, and pseudoaneurysm). These resulted in 3 access-related reinterventions: surgical evacuation of a hematoma, thrombectomy of the occluded brachial artery, and surgical repair of the pseudoaneurysm. In the interim comparison to the 19 matched patients (mean age 61.9 years; 6 men), the ProGlide group had proportionally more patients experiencing access-related complications (57% vs 16% for manual compression, p=0.035) and resultant reinterventions (43% vs 11%, p=0.064). Based on this data the trial was stopped. Conclusion: Considering this experience, it is not advisable to use the ProGlide in transbrachial endovascular interventions due to the high incidence of complications and access-related reinterventions.

A Technical Report on the Performance of a New Large Bore Cerebral Aspiration Catheter, the First Results.

AIMS AND BACKGROUND: We describe the initial results of the Syphontrack Super Distal Access (SDA) catheter (InNeuroco Inc., Sunrise, Fl, USA) used for endovascular treatment of patients with acute ischemic stroke of the anterior circulation. METHODS: A retrospective review of prospectively collected data from June 2017 to May 2018 in Maastricht University Medical Center plus (MUMC +) with direct distal aspiration or a combination of distal aspiration with stent retriever thrombectomy was performed. Primary outcome measurements were accessibility and reperfusion grade (eTICI). Secondary outcome measurements were early neurologic recovery (a decrease of four or more points on the NIHSS), symptomatic intracranial hemorrhage (sICH) within 24 h and mRS score at 3 months. RESULTS: The first 50 patients in whom the SDA catheter was used are included. Direct distal aspiration was performed in 33/50 (66%). In 29/33 (88%), distal position in contact with the clot was achieved of which 15 (52%) were successful (eTICI 2b or higher) after first attempt. Total successful reperfusion rate was 23/50 (46%) after first pass. Final successful reperfusion, after multiple attempts, was reached in 48/50 (96%). Early neurologic recovery was seen in 21/50 (42%), and functional independence (mRS score of 0-2) at 3 months was achieved in 17/50 (35%). sICH occurred in 4/50 (8%) within 24 h post-procedural. CONCLUSION: In our clinical practice, endovascular treatment of ischemic stroke with the SDA catheter had similar technical and clinical results as reported in the literature.

Fluoroscopy with MRA fusion image guidance in endovascular iliac artery interventions: study protocol for a randomized controlled trial (3DMR-Iliac-roadmapping study).

BACKGROUND: Endovascular iliac artery interventions rely on the use of two-dimensional digital subtraction angiographies with an iodinated contrast agent and ionizing radiation. The amount of iodinated contrast agent should be limited because of its potentially nephrotoxic effects. Three-dimensional (3D) image fusion requires registration of a preprocedural magnetic resonance angiogram (MRA) or computed tomography (CT) angiogram to a perprocedurally acquired cone-beam CT or two fluoroscopic orthogonal projections. After registration, the 3D angiography images can be overlaid on the fluoroscopy screen and will follow table and C-arm movements. This study will assess the added value of the 3D image fusion technique in iliac artery interventions regarding the amount of the iodinated contrast agent administered. METHODS/DESIGN: The study cohort will comprise 106 patients (> 18 years) with symptomatic common and/or external iliac artery stenoses or occlusions and a recent (< 6 months) diagnostic MRA from the pelvis through the lower extremities, for which an endovascular intervention is indicated. Patients will be randomized into the control or study group (i.e. treatment without or with 3D image fusion guidance). The primary endpoint is the amount of administered iodinated contrast agent (mL). Secondary outcomes are technical success of the procedure, defined as < 30% residual stenosis over the treated lesion, fluoroscopy time, and radiation dose as dose area product (mGycm2). Patient participation in the study will be completed after hospital discharge. DISCUSSION: This study is a randomized controlled multicenter trial to provide evidence on the effect of the 3D image fusion technique on the amount of administered iodinated contrast during endovascular common and/or external iliac artery interventions. TRIAL REGISTRATION: Nederlands Trial Register, NTR5008 . Registered on 16 December 2014.

Endoscopic versus percutaneous biliary drainage in patients with resectable perihilar cholangiocarcinoma: a multicentre, randomised controlled trial.

BACKGROUND: In patients with resectable perihilar cholangiocarcinoma, biliary drainage is recommended to treat obstructive jaundice and optimise the clinical condition before liver resection. Little evidence exists on the preferred initial method of biliary drainage. We therefore investigated the incidence of severe drainage-related complications of endoscopic biliary drainage or percutaneous transhepatic biliary drainage in patients with potentially resectable perihilar cholangiocarcinoma. METHODS: We did a multicentre, randomised controlled trial at four academic centres in the Netherlands. Patients who were aged at least 18 years with potentially resectable perihilar cholangiocarcinoma requiring major liver resection, and biliary obstruction of the future liver remnant (defined as a bilirubin concentration of >50 µmol/L [2·9 mg/dL]), were randomly assigned (1:1) to receive endoscopic biliary drainage or percutaneous transhepatic biliary drainage through the use of computer-generated allocation. Randomisation, done by the trial coordinator, was stratified for previous (attempted) biliary drainage, the extent of bile duct involvement, and enrolling centre. Patients were enrolled by clinicians of the participating centres. The primary outcome was the number of severe complications between randomisation and surgery in the intention-to-treat population. The trial was registered at the Netherlands National Trial Register, number NTR4243. FINDINGS: From Sept 26, 2013, to April 29, 2016, 261 patients were screened for participation, and 54 eligible patients were randomly assigned to endoscopic biliary drainage (n=27) or percutaneous transhepatic biliary drainage (n=27). The study was prematurely closed because of higher mortality in the percutaneous transhepatic biliary drainage group (11 [41%] of 27 patients) than in the endoscopic biliary drainage group (three [11%] of 27 patients; relative risk 3·67, 95% CI 1·15-11·69; p=0·03). Three of the 11 deaths among patients in the percutaneous transhepatic biliary drainage group occurred before surgery. The proportion of patients with severe preoperative drainage-related complications was similar between the groups (17 [63%] patients in the percutaneous transhepatic biliary drainage group vs 18 [67%] in the endoscopic biliary drainage group; relative risk 0·94, 95% CI 0·64-1·40). 16 (59%) patients in the percutaneous transhepatic biliary drainage group and ten (37%) patients in the endoscopic biliary drainage group developed preoperative cholangitis (p=0·1). 15 (56%) patients required additional percutaneous transhepatic biliary drainage after endoscopic biliary drainage, whereas only one (4%) patient required endoscopic biliary drainage after percutaneous transhepatic biliary drainage. INTERPRETATION: The study was prematurely stopped because of higher all-cause mortality in the percutaneous transhepatic biliary drainage group. Post-drainage complications were similar between groups, but the data should be interpreted with caution because of the small sample size. The results call for further prospective studies and reconsideration of indications and strategy towards biliary drainage in this complex disease. FUNDING: Dutch Cancer Foundation.

Differences in renal hemodynamics and renin secretion between patients with unifocal and multifocal fibromuscular dysplasia.

OBJECTIVE: Fibromuscular dysplasia (FMD) can be classified in a multifocal and a unifocal subtype. As unifocal FMD generally leads to more severe hypertension at younger age, we hypothesized that renal hemodynamics are more disturbed in unifocal renal artery FMD as compared with multifocal FMD, leading to increased renin secretion. METHODS: We measured renal blood flow (Xenon washout method), renin secretion, and glomerular filtration rate per kidney in 101 patients with FMD (26 unifocal and 75 multifocal), all off medication and prior to balloon angioplasty. RESULTS: We found that renal blood flow and glomerular filtration were substantially lower in kidneys with unifocal FMD as compared with multifocal FMD. In the affected kidney from patients with unilateral FMD for example, mean renal blood flow was 173 ±â€Š77 in unifocal vs. 244 ±â€Š79 ml/100 g kidney/min in multifocal FMD (P = 0.013). Moreover, lateralization in renin secretion was only observed in a subset of patients with unifocal FMD, but not in any of the patients with multifocal FMD. CONCLUSION: These findings suggest that the impact of unifocal FMD lesions on the kidney is more severe, resulting in a classical pattern of renovascular hypertension. In multifocal FMD, however, renal blood flow is more preserved, local renin secretion is not increased, and the association between renin levels and blood pressure is inverse. These differences may explain the often more severe clinical presentation and higher success rate of revascularization in unifocal FMD, but also suggest that the pathophysiological mechanisms leading to hypertension may differ between these two disease entities.

A Systematic Review and Meta-Analysis on Outcomes and Complications of Percutaneous Endoscopic Versus Radiologic Gastrostomy for Enteral Feeding.

BACKGROUND: The optimal technique for long-term enteral feeding has not yet been established. Both percutaneous endoscopic gastrostomy (PEG) and percutaneous radiologic gastrostomy (PRG) are widely used. Aim was to extensively review outcomes of PEG and PRG. MATERIALS AND METHODS: A systematic review using Medline, Embase, and Cochrane was performed, using standardized tools for assessing bias. Main outcomes were infectious and tube-related complications, procedure related and 30-day mortality. Pooled risk differences (RDs) with corresponding 95% confidence intervals (95% CIs) were calculated using random effects. Arcsine transformations were applied. RESULTS: In total, 344 studies were identified, of which 16 were included, reporting on 934 PEGs and 1093 PRGs. No differences were found for infectious complications [RD, 0.03 (-0.05 to 0.11)], procedure-related mortality [RD, 0.01 (-0.04 to 0.06)], or 30-day mortality [RD, 0.06 (-0.01 to 0.13)]. Tube-related complications were higher in PRG [RD, 0.16 (0.06-0.26)]. Subgroup analysis was performed for head and neck cancer (HNC) and motor neuron disease. In HNC, this revealed significantly lower tube-related complications and procedure-related mortality after PEG. In motor neuron disease, no differences were seen. The level of evidence appears sufficient considering the low degree of heterogeneity. CONCLUSIONS: No differences were found with regard to mortality or infectious complications. PEG showed lower risk of tube-related complications. Subgroup analysis revealed PEG to be favorable in HNC based on lower rates of procedure-related mortality and tube-related complications. Local experience and availability should be taken into account in the decision process.

Implementation of Size-Dependent Local Diagnostic Reference Levels for CT Angiography.

OBJECTIVE: Diagnostic reference levels (DRLs) are established for standard-sized patients; however, patient dose in CT depends on patient size. The purpose of this study was to introduce a method for setting size-dependent local diagnostic reference levels (LDRLs) and to evaluate these LDRLs in comparison with size-independent LDRLs and with respect to image quality. MATERIALS AND METHODS: One hundred eighty-four aortic CT angiography (CTA) examinations performed on either a second-generation or third-generation dual-source CT scanner were included; we refer to the second-generation dual-source CT scanner as "CT1" and the third-generation dual-source CT scanner as "CT2." The volume CT dose index (CTDIvol) and patient diameter (i.e., the water-equivalent diameter) were retrieved by dose-monitoring software. Size-dependent DRLs based on a linear regression of the CTDIvol versus patient size were set by scanner type. Size-independent DRLs were set by the 5th and 95th percentiles of the CTDIvol values. Objective image quality was assessed using the signal-to-noise ratio (SNR), and subjective image quality was assessed using a 4-point Likert scale. RESULTS: The CTDIvol depended on patient size and scanner type (R2 = 0.72 and 0.78, respectively; slope = 0.05 and 0.02 mGy/mm; p < 0.001). Of the outliers identified by size-independent DRLs, 30% (CT1) and 67% (CT2) were adequately dosed when considering patient size. Alternatively, 30% (CT1) and 70% (CT2) of the outliers found with size-dependent DRLs were not identified using size-independent DRLs. A negative correlation was found between SNR and CTDIvol (R2 = 0.36 for CT1 and 0.45 for CT2). However, all outliers had a subjective image quality score of sufficient or better. CONCLUSION: We introduce a method for setting size-dependent LDRLs in CTA. Size-dependent LDRLs are relevant for assessing the appropriateness of the radiation dose for an individual patient on a specific CT scanner.

The use of 3D image fusion for percutaneous transluminal angioplasty and stenting of iliac artery obstructions: validation of the technique and systematic review of literature.

INTRODUCTION: The effect of the insertion of guidewires and catheters on fusion accuracy of the three-dimensional (3D) image fusion technique during iliac percutaneous transluminal angioplasty (PTA) procedures has not yet been investigated. EVIDENCE ACQUISITION: Technical validation of the 3D fusion technique was evaluated in 11 patients with common and/or external iliac artery lesions. A preprocedural contrast-enhanced magnetic resonance angiogram (CE-MRA) was segmented and manually registered to a cone-beam computed tomography image created at the beginning of the procedure for each patient. The treating physician visually scored the fusion accuracy (i.e., accurate [<2 mm], mismatch [2-5 mm], or inaccurate [>5 mm]) of the entire vasculature of the overlay with respect to the digital subtraction angiography (DSA) directly after the first obtained DSA. Contours of the vasculature of the fusion images and DSAs were drawn after the procedure. The cranial-caudal, lateral-medial, and absolute displacement were calculated between the vessel centerlines. To determine the influence of the catheters, displacement of the catheterized iliac trajectories were compared with the noncatheterized trajectories. Electronic databases were systematically searched for available literature published between January 2010 till August 2017. EVIDENCE SYNTHESIS: The mean registration error for all iliac trajectories (N.=20) was small (4.0±2.5 mm). No significant difference in fusion displacement was observed between catheterized (N.=11) and noncatheterized (N.=9) iliac arteries. The systematic literature search yielded 2 manuscripts with a total of 22 patients. The methodological quality of these studies was poor (≤11 MINORS Score), mainly due to a lack of a control group. CONCLUSIONS: Accurate image fusion based on preprocedural CE-MRA is possible and could potentially be of help in iliac PTA procedures. The flexible guidewires and angiographic catheters, routinely used during endovascular procedures of iliac arteries, did not cause significant displacement that influenced the image fusion. Current literature on 3D image fusion in iliac PTA procedures is of limited methodological quality.

The Lateral Thigh Perforator Flap for Autologous Breast Reconstruction: A Prospective Analysis of 138 Flaps.

BACKGROUND: The septocutaneous tensor fasciae latae or lateral thigh perforator flap was previously introduced by the authors' group as an alternative flap for autologous breast reconstruction when the abdomen is not suitable as a donor site. The authors analyzed their experience with the lateral thigh perforator flap and present the surgical refinements that were introduced. METHODS: A prospective study was conducted of all lateral thigh perforator flap breast reconstructions performed since September of 2012. Patient demographics, operative details, complications, and flap reexplorations were recorded. Preoperative imaging with magnetic resonance angiography was performed in all patients. Surgical refinements introduced during this study included limitation of the flap width and the use of quilting sutures at the donor site. RESULTS: A total of 138 lateral thigh perforator flap breast reconstructions were performed in 86 consecutive patients. Median operative times were 277 minutes (range, 196 to 561 minutes) for unilateral procedures and 451 minutes (range, 335 to 710 minutes) for bilateral. Median flap weight was 348 g (range, 175 to 814 g). Two total flap losses (1.4 percent) were recorded, and 11 flaps (8.0 percent) required reexploration, which resulted in viable flaps. The incidence of donor-site complications was reduced significantly after the surgical refinements were introduced. Wound problems decreased from 40.0 percent to 6.3 percent, seroma decreased from 25.0 percent to 9.5 percent, and infection decreased from 27.5 percent to 9.5 percent. CONCLUSIONS: The lateral thigh perforator flap is an excellent option for autologous breast reconstruction, with minimal recipient-site complications. The surgical refinements resulted in a significant reduction of donor-site complications. Therefore, the lateral thigh perforator flap is currently the authors' second choice after the deep inferior epigastric artery perforator flap. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.