Inferior vena cava filter - comprehensive overview of current indications, techniques, complications and retrieval rates.

Inferior vena cava (IVC) filter has been used to manage patients with pulmonary embolism and deep venous thrombosis. Its ease of use and the expansion of relative indications have led to a dramatic increase in IVC filter placement. However, IVC filters have been associated with a platitude of complications. Therefore, there exists a need to examine the current indications and identify the patient population at risk. In this paper, we comprehensively reviewed the current indications and techniques of IVC filter placement. Further, we examined the various complications associated with either permanent or retrievable IVC filters. Lastly, we examined the current data on filter retrieval.

Quantification of Blood Flow in Dialysis Access Using Custom-Acquisition Protocol and Imaging Methods: A Clinical Validation Study.

PURPOSE: To determine access blood flow (ABF) rate using 2D image sequences acquired with digital subtraction angiography (DSA) and fluoroscopy. MATERIALS AND METHODS: A total of 23 patients with known or suspected malfunctioning accesses were imaged using 2 filming modes: DSA at 3 or 6 frames/s (F/s), and fluoroscopy at 10 or 15 pulses/s (P/s). ABF rates were quantified using a bolus tracking method based on cross-correlation algorithm and compared with catheter-based thermal dilution (TD) flow measurements. The indicator-dilution curves were fitted with a gamma-variate (GV) curve fitting model to assess the effect on accuracy. Radiation doses were calculated to examine any increased susceptibility to tissue reactions and stochastic effects. RESULTS: For DSA images, the absolute percent deviations (mean ± standard error of mean) in computed flow vs TD flow measurements at 3 F/s and 6 F/s were 34% ± 4.5% and 20% ± 4.7%, respectively, without curve fitting, and 31% ± 3.3% and 20% ± 4.1%, respectively, with curve fitting. For fluoroscopic images, the deviations at 10 P/s and 15 P/s were 44% ± 7.3% and 68% ± 10.7%, respectively, without curve fitting and 36% ± 6.4% and 48% ± 7.1%, respectively, with curve fitting. The mean peak skin dose and effective dose at 6 F/s were 3.28 mGy and 75 µSv, respectively. CONCLUSIONS: Digital subtraction angiography images obtained at 6 F/s offered the highest accuracy for dialysis access blood flow quantification.

Placing an appropriate tunneled dialysis catheter in an appropriate patient including the nonconventional sites.

Hemodialysis remains the most frequently chosen kidney replacement modality across the world. A well-functioning dialysis vascular access is critical to providing successful dialysis therapy. Despite its drawbacks, central venous catheter is commonly used as a vascular access to initiate hemodialysis therapy in acute and chronic settings. The growing recognition of providing patient centric care and per recommendations from the recently published Kidney Disease Outcome Quality Initiative (KDOQI) Vascular Access Guidelines, selecting the appropriate patient population for a central venous catheter placement involves implementing the End Stage Kidney Disease (ESKD) Life-Plan strategy. The current review examines the circumstances and challenges that increasingly lead to the hemodialysis catheter being the default and the only available choice for patients. The current review outlines the clinical scenarios for selecting an appropriate patient for hemodialysis catheter use for short-term or long-term needs. The review further discusses clinical pointers to assist with the decision-making process on estimation on prospective catheter length selection, particularly in the intensive care unit setting without the aid of conventional fluoroscopic guidance. A hierarchy of conventional and non-conventional access sites is proposed based on KDOQI guidance and multi-disciplinary author experience. Non-conventional sites are reviewed, including complications and technical guidance, for trans-lumbar IVC, trans-hepatic, trans-renal, and other exotic sites.

Implementing an Interdisciplinary Procedure Curriculum.

INTRODUCTION: This curriculum was designed to improve access to procedures for our internal medicine residents. METHODS: We created an interdisciplinary procedure course (IDPC) composed of two simulation sessions and a one-week procedural rotation supervised by multiple specialties including nephrology, cardiology, cardiothoracic anesthesiology, general anesthesiology, and interventional radiology. After the course, residents completed two surveys documenting the number of procedures and their level of confidence on a Likert scale (1 = very unconfident to 5 = very confident) prior to and after completing the curriculum. RESULTS: Sixteen residents participated in the course from September 2021 to June 2022. The collective number of procedures performed by these 16 residents increased from 176 to 343 after a one-week rotation. For arterial lines, the proportion of residents that reported an improvement in confidence scores was 0.44 (95% confidence interval 0.23 to 1, p-value of 0.60). The proportion of residents that had an increase in their confidence performing central lines was 0.63 (95% confidence interval 0.39 to 1, p-value of 0.23). For intubations, the proportion of residents that reported an improvement in confidence was 0.94 (95% confidence interval 0.72 to 1, p-value of 0.0006). CONCLUSION: By collaborating with multiple specialties, residents almost doubled the number of procedures performed during training and reported an increased level of confidence in procedural performance for airway intubation. We learned residents want to improve their access to procedures and described a curriculum that was easily implemented.

Imaging features of idiopathic intracranial hypertension, including a new finding: widening of the foramen ovale.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a clinical disorder of unknown etiology manifesting with increased intracranial pressure in the absence of hydrocephalus, an underlying mass lesion, and demonstrating normal cerebrospinal fluid composition. IIH may exhibit several non-specific imaging findings including: an empty sella, posterior globe flattening, tortuosity of the optic nerve, and optic nerve sheath distention. PURPOSE: To introduce widening of the foramen ovale as a new imaging marker for IIH. MATERIAL AND METHODS: IIH is a syndrome which may exhibit several previously described non-specific imaging findings including: an empty sella, posterior globe flattening, tortuosity of the optic nerve, and optic nerve sheath distention. We hypothesize that chronically elevated cerebrospinal fluid pressure can lead to osseous erosions and we propose widening of the foramen ovale as a new imaging marker for IIH. RESULTS: Average foramen ovale sizes were increased in patients with IIH compared to controls (30.03 ± 7.00 mm(2) vs. 24.21 ± 5.97 mm(2), P < 0.001). For a cut-off value of 30 mm(2), the sensitivity of FO area to detect IIH was 50%, with 81% specificity. Classic findings were significantly more common in patients with IIH compared to controls including: empty sella (65.9% vs. 0%), posterior globe flattening (65.9% vs. 4.5%), vertical tortuosity of the optic nerve (54.5% vs. 9.1%), and optic nerve sheath distention (52.3% vs. 11.4%, all P values < 0.001). CONCLUSION: Our study confirms the association of several classic imaging findings with IIH and supports widening of the foramen ovale as an additional imaging marker which may be incorporated into the evaluation of patients suspected to have this condition.

Hepatic Encephalopathy After TIPS Placement: Predictive Factors, Prevention Strategies, and Management.

Hepatic encephalopathy (HE) is a challenging complication after transjugular intrahepatic portosystemic shunt (TIPS) placement. Despite recent advances, much is still uncertain regarding risk factors, preventative measures, and the management of HE after TIPS placement. Appropriate patient selection and pre-procedural risk stratification remain areas of focus. In this manuscript, we discuss the current state of research related to HE after TIPS placement, including information regarding risk stratification, complication prevention, and treatment options.

Acute pulmonary embolism multimodality imaging prior to endovascular therapy.

The manuscript discusses the application of CT pulmonary angiography, ventilation-perfusion scan, and magnetic resonance angiography to detect acute pulmonary embolism and to plan endovascular therapy. CT pulmonary angiography offers high accuracy, speed of acquisition, and widespread availability when applied to acute pulmonary embolism detection. This imaging modality also aids the planning of endovascular therapy by visualizing the number and distribution of emboli, determining ideal intra-procedural catheter position for treatment, and signs of right heart strain. Ventilation-perfusion scan and magnetic resonance angiography with and without contrast enhancement can also aid in the detection and pre-procedural planning of endovascular therapy in patients who are not candidates for CT pulmonary angiography.

Advanced portal venous access techniques for transjugular intrahepatic portosystemic shunt placement.

INTRODUCTION: Transjugular intrahepatic portosystemic shunt (TIPS) placement is a well-established but technically challenging procedure for the management of sequelae of end-stage liver disease. Performed essentially blindly, traditional fluoroscopically guided TIPS placement requires multiple needle passes and prolonged radiation exposure to achieve successful portal venous access, thus increasing procedure time and the risk of periprocedural complications. Several advanced image-guided portal access techniques, including intracardiac echocardiography (ICE)-guided access, cone-beam CT (CBCT)-guided access and wire-targeting access techniques, can serve as alternatives to traditional CO2 portography-based TIPS creation. METHODS: A literature search was performed on the electronic databases including MEDLINE and Embase, from 2000 to the present to identify all relevant studies. The reference list also included studies identified manually, and studies referenced for other purposes. FINDINGS: The main benefit of these advanced access techniques is that they allow the operator to avoid essentially blind portal punctures, and the ability to visualise the target, thus reducing the number of required needle passes. Research has shown that ICE-guided access can decrease the radiation exposure, procedure time and complication rate in patients undergoing TIPS placement. This technique is particularly useful in patients with challenging portal venous anatomy. However, ICE-guided access requires additional equipment and possibly a second operator. Other studies have shown that CBCT-guided access, when compared with traditional fluoroscopy-guided access, provides superior visualisation of the anatomy with similar amount of radiation exposure and procedure time. The wire-targeting technique, on the other hand, appears to offer reductions in procedure time and radiation exposure by enabling real-time guidance. However, this technique necessitates percutaneous injury to the liver parenchyma in order to place the target wire. CONCLUSION: Advanced portal access techniques have certain advantages over the traditional fluoroscopically guided TIPS access. To date, few studies have compared these advanced guided access options, and further research is required.

Lower extremity CT angiography in peripheral arterial disease: from the established approach to evolving technical developments.

With the advent of multidetector computed tomography (CT), CT angiography (CTA) has gained widespread popularity for noninvasive imaging of the arterial vasculature. Peripheral extremity CTA can nowadays be performed rapidly with high spatial resolution and a decreased amount of both intravenous contrast and radiation exposure. In patients with peripheral artery disease (PAD), this technique can be used to delineate the bilateral lower extremity arterial tree and to determine the amount of atherosclerotic disease while differentiating between acute and chronic changes. This article provides an overview of several imaging techniques for PAD, specifically discusses the use of peripheral extremity CTA in patients with PAD, clinical indications, established technical considerations and novel technical developments, and the effect of postprocessing imaging techniques and structured reporting.

Image guided percutaneous gastrostomy catheter placement: How we do it safely and efficiently.

Gastrostomy tube is an effective and safe long-term feeding access that is well-tolerated by patients. The typical placement routes include surgical, endoscopic and interventional radiologic placement. In particular, percutaneous interventional radiologic gastrostomy (PIRG) has increasingly become the preferred method of choice in many practices. Although many PIRG techniques have been developed since the 1980s, there is still a paucity of evidence supporting the choice of a most-optimal PIRG technique. Hence, there is a large variation in institutional approach to PIRG. We are a large, quaternary academic institution with an extensive experience in PIRG. Therefore, we aim to present the "push" PIRG technique utilized in our institution, to review the current literature, to discuss the optimal choice of PIRG technique and to generate further interests in comparison studies.

Does a tensioning device pinned to the tibia improve knee anterior-posterior load-displacement compared to manual tensioning of the graft following anterior cruciate ligament reconstruction? A cadaveric study of two tibial fixation devices.

Devices that are pinned to the tibia to tension an anterior cruciate ligament (ACL) graft produce joint reaction loads that in turn can affect the maintenance of graft initial tension after tibial fixation and hence knee anterior-posterior (AP) load-displacement. However, the effect of these devices on AP load-displacement is unknown. Our objectives were to determine whether tensioning by device versus tensioning by hand causes differences in AP load-displacement and intraarticular graft tension for two commonly used tibial fixation devices: a bioresorbable interference screw and a WasherLoc. AP load-displacement and intraarticular graft tension were measured in 20 cadaveric knees using a custom arthrometer. An initial tension of 110 N was applied to a double-looped tendon graft with the knee at extension using a tensioning device pinned to the tibia and a simulated method of tensioning by hand. After inserting the tibial fixation device, the 134 N anterior limit (i.e., anterior position of the tibia with respect to the femur with a 134 N anterior force applied to the tibia) and 0 N posterior limit (i.e., AP position of the tibia relative to the femur with a 0 N force applied to the tibia) were measured with the knee in 25 degrees flexion. Intraarticular graft tension was measured at extension. These limits and intraarticular graft tension were also measured after cyclically loading the knee 300 times. Compared to a simulated method of tensioning by hand, tensioning with a device pinned to the tibia did not decrease the 134 N anterior limit and did not cause posterior tibial translation. However, intraarticular graft tension was maintained better with a tensioning device pinned to the tibia for the Washerloc, but not the interference screw. For two commonly used tibial fixation devices, a tensioning device pinned to the tibia does not improve AP load-displacement at 25 degrees flexion over tensioning by hand when the graft is tensioned at full extension, but does improve the maintenance of intraarticular graft tension for the Washerloc.

Peritoneal Dialysis.

Peritoneal dialysis is becoming more important in the management of patients with end-stage renal disease. Because of the efforts of the "Fistula First Breakthrough Initiative," dialysis venous access in the United States has become focused on promoting arteriovenous fistula creation and reducing the number of patients who start dialysis with a tunneled catheter. This is important because tunneled catheters can lead to infection, endocarditis, and early loss of more long-term access. When planned for, peritoneal dialysis can offer patients the opportunity to start dialysis at home without jeopardizing central access or the possibilities of eventual arteriovenous fistula creation. The purpose of this review is to highlight the indications, contraindications, and procedural methods for implanting peritoneal dialysis catheters in the interventional radiology suite.

Empirical relationship between lengthening an anterior cruciate ligament graft and increases in knee anterior laxity: a human cadaveric study.

Lengthening of an anterior cruciate ligament (ACL) graft construct can occur as a result of lengthening at the sites of tibial and/or femoral fixation and manifests as an increase in anterior laxity. Although lengthening at the site of fixation has been measured for a variety of fixation devices, it is difficult to place these results in a clinical context because the mathematical relationship between lengthening of an ACL graft construct and anterior laxity is unknown. The purpose of our study was to determine empirically this relationship. Ten cadaveric knees were reconstructed with a double-looped tendon graft. With the knee in 25 degrees of flexion, the position of the proximal end of the graft inside the femoral tunnel was adjusted by moving the femoral fixation device until the anterior laxity at an applied anterior force of 134 N matched that of the intact knee. In random order, the graft construct was lengthened 1, 2, 3, 4, and 5 mm by moving the femoral fixation device distally along the femoral tunnel and anterior laxity was measured. The increase in the length of the graft construct was related to the increase in anterior laxity by a simple linear regression model. Lengthening the graft construct from 1 to 5 mm caused an equal increase in anterior laxity (slope=1.0 mmmm, r(2)=0.800, p<0.0001). Because an anterior laxity increase of 3 mm or greater in a reconstructed knee is considered unstable clinically and because many fixation devices in widespread use clinically allow 3 mm or greater of lengthening in in vitro tests, our empirical relationship indicates that lengthening at the site of fixation probably is an important cause of knee instability following ACL reconstructive surgery. Our empirical relation also indicates that an important criterion in the design of future fixation devices is that lengthening at the sites of fixation in in vitro tests should be limited to less than 3 mm.