A Pilot Study Assessing the Impact of 3-D Printed Models of Aortic Aneurysms on Management Decisions in EVAR Planning.

INTRODUCTION: Endovascular repair of aortic aneurysms with difficult anatomy is challenging. There is no consensus for planning such procedures. METHODS: Six cases of aortic aneurysms with challenging anatomical features, such as short, angulated, and conical necks and tortuous iliacs were harvested. The computed tomography (CT) scans were anonymized. Lifesize 3-dimensional (3-D) printed models were created of the lumen. Endovascular operators were asked to review the CT angiography (CTA), make a management plan, and give an indication of their confidence. They were then presented with the equivalent model and asked to review their decision. Their attitudes to such models were briefly surveyed. RESULTS: A total of 28 endovascular operators reviewed 144 cases. After review of the physical model, the management plan changed in 29 (20.1%) of 144 cases. Initial plan after CTA review was endovascular 73.6%, open repair 22.9%, and second opinion 3.5%. After model review, this became endovascular 67.4%, open repair 19.4%, and second opinion 4.8%. Although the general trend was toward more open procedures, off-label techniques reduced from 19.4% to 15.2% following model review. When the management plan did not change, level of confidence did increase in 37 (43.5%) of 85 cases. The majority of operators stated that they would find models useful for planning in some procedures. For 1 case, the change in the percentage of participants being sure in the management plan was statistically significant (P = .031). CONCLUSION: The 3-D printed models may be potentially useful in planning cases with EVAR. It is a paradigm that warrants further investigation.

Transjugular intrahepatic portosystemic shunt in liver transplant recipients: indications, feasibility, and outcomes.

The role of transjugular intrahepatic portosystemic shunt (TIPS) for treating complications of portal hypertension after orthotopic liver transplantation (OLT) is unclear. In this review of 13 retrospective studies and 8 case reports comprising 213 patients, we assessed the indications, technical success, and clinical outcomes of TIPS procedures performed in patients who had undergone OLT. Indications for TIPS were refractory ascites (n = 168), variceal hemorrhage (n = 36), and hydrothorax (n = 9). Technical success was reported in 98% of cases. Five procedures failed because of portal vein thrombosis, caval tear, technical inability, patient instability, and unknown reasons (one each). Clinical success of TIPS after OLT was 57% in patients with refractory ascites, 69% in those with variceal hemorrhage, and 56% in those with hydrothorax. TIPS revision was required in 16% of cases, while 19% of patients underwent subsequent retransplantation. Postprocedural or worsening encephalopathy occurred in 33% of patients. Survival analysis based on 122 cases with data available revealed a 30-day mortality rate of 11%, a 1-year cumulative survival rate of 53%, and a 1-year cumulative retransplantation-free survival rate of 41%. Given the complexity of post-OLT cases with complications of recurrent portal hypertension, it is not surprising that the overall clinical success rate of TIPS was relatively low. Nevertheless, TIPS may remain a viable choice for the treatment of patients who have undergone OLT with recurrent portal hypertensive complications when medical therapy is unsuccessful.

Functional lengths of the lower limb arterial tree measured by CT angiography centreline analysis: implications for catheter lengths in peripheral angioplasty.

PURPOSE: Lower limb angioplasty is a common procedure. However, arterial lengths have not been well studied and there is no evidence base for the optimum catheter lengths required for the various applications of femoral or distal below-the-knee angioplasty. The industry standard catheter measures 80 cm. METHOD: Fifty CT angiograms were post-processed using vessel tracking and centreline analysis tools and lengths were measured from the ipsilateral first segment of the femoral artery (FSFA) (common femoral artery) to the contralateral FSFA and on to the second segment of the femoral artery (superficial femoral artery) and popliteal arteries down to the posterior tibial (PT) artery at the ankle. This allowed clinically meaningful lengths for 'cross-over' and 'antegrade' angioplasty to be calculated. RESULTS: Mean cross-over length to the second segment of the femoral artery as it crossed the femoral cortex was 72.3 cm, and the mean cross-over length to the popliteal artery at the knee joint was 83.8 cm, and the length from the FSFA to the PT was 85.1 cm. CONCLUSION: Selection of a standard length catheter can result in a situation where the catheter is too short. Optimum catheter length for a particular task will reduce the need for catheter exchanges and use of multiple balloons and therefore reduce complications, procedure time, radiation dose and cost.

3D printing of an aortic aneurysm to facilitate decision making and device selection for endovascular aneurysm repair in complex neck anatomy.

PURPOSE: To describe rapid prototyping or 3-dimensional (3D) printing of aneurysms with complex neck anatomy to facilitate endovascular aneurysm repair (EVAR). CASE REPORT: A 75-year-old man had a 6.6-cm infrarenal aortic aneurysm that appeared on computed tomographic angiography to have a sharp neck angulation of ~90°. However, although the computed tomography (CT) data were analyzed using centerline of flow, the true neck length and relations of the ostial origins were difficult to determine. No multidisciplinary consensus could be reached as to which stent-graft to use owing to these borderline features of the neck anatomy. Based on past experience with rapid prototyping technology, a decision was taken to print a model of the aneurysm to aid in visualization of the neck anatomy. The CT data were segmented, processed, and converted into a stereolithographic format representing the lumen as a 3D volume, from which a full-sized replica was printed within 24 hours. The model demonstrated that the neck was adequate for stent-graft repair using the Aorfix device. CONCLUSION: Rapid prototyping of aortic aneurysms is feasible and can aid decision making and device delivery. Further work is required to test the value of 3D replicas in planning procedures and their impact on procedure time, radiation dose, and procedure cost.

Gelfoam-assisted amplatzer vascular plug technique for rapid occlusion in proximal splenic artery embolization.

OBJECTIVE: The objective of this study was to prospectively investigate the role of rapid Gelfoam-assisted occlusion of the splenic artery with an Amplatzer Vascular Plug (AVP). Ten consecutive proximal splenic artery embolizations were performed with AVP as the primary embolic agent and Gelfoam slurry as an adjunct. These cases were then compared with 10 retrospective cases of splenic artery embolization performed with AVP and augmented with coils or additional AVPs, or both, in patients with similar indications. CONCLUSION: Successful proximal splenic artery embolization using a single Amplatzer Vascular Plug and Gelfoam slurry occurred in all cases. No recanalization was identified on imaging follow-up at an average interval of 5.1 months. Gelfoam can be used as an adjunct to AVP in proximal splenic artery embolization. Using adjunctive Gelfoam is a simple, safe, and cost-saving method of improving the occlusion efficiency of the Amplatzer Vascular Plug.

3-D printout of a DICOM file to aid surgical planning in a 6 year old patient with a large scapular osteochondroma complicating congenital diaphyseal aclasia.

A 6 year old girl presented with a large osteochondroma arising from the scapula. Radiographs, CT and MRI were performed to assess the lesion and to determine whether the lesion could be safely resected. A model of the scapula was created by post-processing the DICOM file and using a 3-D printer. The CT images were segmented and the images were then manually edited using a graphics tablet, and then an STL-file was generated and a 3-D plaster model printed. The model allowed better anatomical understanding of the lesion and helped plan surgical management.

The amplatzer vascular plug: a review of the device and its clinical applications.

The Amplatzer Vascular Plug (AVP) is an established embolic device that can be an excellent alternative to coils or detachable balloons to embolize medium to large vessels with high flow. The device is easy to use and can be precisely deployed in the target vessel with high resistance to migration and a low recanalization rate. The technical success of this device is high, indications for use are expanding, and no absolute contraindications have been reported. Since its introduction, the AVP has grown from a single device to a group of 4 models (AVP, AVP II, AVP III, and AVP 4). Each model has a unique design and features that fit different vascular anatomies, hemodynamic situations, and clinical scenarios. Therefore, the new models cannot simply be treated as replacements for older ones. Unpredictable occlusion time remains a major shortcoming for the new models of the AVP. Large vessel size, high flow status, and coagulopathy can prolong the occlusion time, which can offset the cost benefit, reduced procedure time, and reduced radiation dose typically seen with use of the AVP alone. Coils or multiple AVPs can be used to expedite the occlusion process, and large Gelfoam particles also can be used as an adjunct to achieve rapid and reliable occlusion with minimal cost.

Use of an Amplatzer vascular plug II for aortic sac occlusion after failed surgical ligation.

PURPOSE: To present a case of aortic sac occlusion using an Amplatzer vascular plug II (AVP). CASE REPORT: A patient with sigmoid malignancy and an infrarenal aortic aneurysm ultimately required an axillobifemoral graft for acute limb ischemia. The sac was ligated at subsequent laparotomy. Persistent filling of the sac was seen post surgery, and the sac was successfully occluded with placement of an AVP in the neck of the sac in conjunction with coil embolization of lumbar arteries. Sac occlusion was confirmed at follow-up CT. CONCLUSION: The AVP was successfully used to occlude an aortic sac after failed surgical ligation, another novel indication for this versatile embolic device.

The effect of skin entry site, needle angulation and soft tissue compression on simulated antegrade and retrograde femoral arterial punctures: an anatomical study using Cartesian co-ordinates derived from CT angiography.

PURPOSE: Safe femoral arterial access is an important procedural step in many interventional procedures and variations of the anatomy of the region are well known. The aim of this study was to redefine the anatomy relevant to the femoral arterial puncture and simulate the results of different puncture techniques. METHODS: A total of 100 consecutive CT angiograms were used and regions of interest were labelled giving Cartesian co-ordinates which allowed determination of arterial puncture site relative to skin puncture site, the bifurcation and inguinal ligament (ING). RESULTS: The ING was lower than defined by bony landmarks by 16.6 mm. The femoral bifurcation was above the inferior aspect of the femoral head in 51% and entirely medial to the femoral head in 1%. Simulated antegrade and retrograde punctures with dogmatic technique, using a 45-degree angle would result in a significant rate of high and low arterial punctures. Simulated 50% soft tissue compression also resulted in decreased rate of high retrograde punctures but an increased rate of low antegrade punctures. CONCLUSIONS: Use of dogmatic access techniques is predicted to result in an unacceptably high rate of dangerous high and low punctures. Puncture angle and geometry can be severely affected by patient obesity. The combination of fluoroscopy to identify entry point, ultrasound-guidance to identify the femoral bifurcation and soft tissue compression to improve puncture geometry are critical for safe femoral arterial access.

Fracture and distant migration of the Bard Recovery filter: a retrospective review of 363 implantations for potentially life-threatening complications.

PURPOSE: To report the occurrence of fracture of the Recovery filter and incidence of potentially life-threatening complications associated with fractured fragment migration. MATERIALS AND METHODS: A retrospective study of images obtained after placement of Recovery inferior vena cava (IVC) filters from 2003 to 2006 was conducted at a single tertiary-care center. Images were reevaluated for fracture and migration; complications related to filter fracture were investigated. Kaplan-Meier survival analysis was performed to investigate the relationship between time in situ and fracture. RESULTS: A total of 363 Recovery filters were placed; 97 were retrieved, leaving 266 filters in situ (135 patients subsequently died of other causes). The following images were evaluated: 130 chest computed tomography (CT) scans, 153 abdominal CT scans, 254 chest radiographs, 148 radiographs of the abdomen/pelvis, and 106 cavagrams. Mean imaging follow-up interval was 18.4 months (maximum, 81.3 mo). No en bloc migration occurred outside the IVC. Twenty-six limb fractures (all short limbs) were identified in 20 patients; the earliest occurred at 4.1 months. Eight fragment migrations occurred into pulmonary arteries, seven into iliac/femoral veins, one into the right ventricle, and one into the renal vein. Seven fragments were intracaval near the filter, one was extracaval, and one could not be located. Kaplan-Meier survival estimates predicted a fracture rate of 40% at 5.5 years. Of the 20 patients with filter fractures, three died of unrelated causes and 17 remain asymptomatic. CONCLUSIONS: Recovery filter fractures occurred at the short limb only, with a suggested 5.5-year fracture risk of 40%. No life-threatening events occurred in patients with filter fracture.

Retrievability and device-related complications of the G2 filter: a retrospective study of 139 filter retrievals.

PURPOSE: To evaluate the retrievability and safety of the G2 filter. MATERIALS AND METHODS: A retrospective study of all G2 filter retrievals at a single institution was conducted. Hospital records and imaging studies were reviewed for complications, and factors affecting retrieval were analyzed. RESULTS: From 2005 to 2009, a total of 139 patients presented for retrieval of their G2 filter, and 131 pairs of pre- and post-placement cavagrams and 39 computed tomography scans were available for analysis. The following findings were recorded: limb penetration (n = 33), tilt greater than 15° (n = 22), local migration greater than 2 cm (n = 17), retained thrombus within the filter (n = 16), deformity (n = 10), inferior vena cava (IVC) occlusion (n = 3), fracture (n = 2), and pulmonary embolism breakthrough (n = 2). A total of 118 filters were removed, with a mean indwelling time of 131.8 days (range, 3-602 d). Indwell time (< 90, 90-180, or > 180 d) did not affect retrieval (P = .4). There were 21 filters (15.1%) left in situ as a result of severe tilt (n = 9), significant thrombus in the filter (n = 5), IVC occlusion (n = 3), filter incorporation into the caval wall (n = 3), or lack of central venous access (n = 1). There was a strong relationship between penetration and caudal migration (P < .0001). Severe tilt was associated with prolonged fluoroscopic times for retrieval (P = .003). CONCLUSIONS: The majority of G2 filters can be removed without difficulty. The most common factor affecting retrieval was severe tilting. The indwelling time had no impact on retrieval. G2 filter-related complications were frequent but most, including fractures, were clinically insignificant.

Utility of the Amplatzer Vascular Plug in splenic artery embolization: a comparison study with conventional coil technique.

PURPOSE: To retrospectively evaluate the role of the Amplatzer Vascular Plug (AVP) in proximal splenic artery embolization (SAE) compared with coils. MATERIALS AND METHODS: Forty patients had proximal SAE performed with AVP(s) or coils as the primary embolic agent for splenic artery steal syndrome (n=23), trauma (n=5), portal hypertension (n=5), bleeding due to pancreatic pathology (n=4), and pre-splenectomy (n=3). Comparisons were made of occlusion and procedure time, cost, and radiation dose. RESULTS: Eighteen proximal SAE procedures were successfully performed with AVP. Twenty-two procedures were performed with coils, including one failed AVP attempt, which was completed with coils. Precise deployment without migration was achieved in all 18 AVP cases. Seven of 22 (31.8%) coil procedures had distal migration without consequence. There was no statistically significant difference in mean occlusion time (24.4 min for AVP vs. 31.5 min for coils, P=0.13), procedure time (43.7 min for AVP vs. 53.8 min for coils, P=0.16), or cost ($1474.13 for AVP vs. $1722.51 for coils, P=0.69). There was significant difference in radiation dose (842 mGy for AVP vs. 1,309 mGy for coils, P=0.04). Fourteen of the 18 (78%) AVP devices required additional embolic material. CONCLUSIONS: AVP with additional embolic agents is a useful alternative for proximal SAE because of precise deployment, resistance to migration, and radiation reduction. AVP use may be limited by vessel tortuosity. The occlusion time, procedure time, and cost were reduced but this was not statistically significant due to the need for additional embolic material.

Acute abdominal pain after retrievable inferior vena cava filter insertion: case report of caval perforation by an option filter.

Symptomatic caval injury is rare after inferior vena cava (IVC) filter insertion. A 39-year-old woman developed acute abdominal pain after uneventful placement of a retrievable Option IVC Filter (Angiotech Pharmaceuticals, Vancouver, British Columbia, Canada). Two days after placement, computed tomography showed a right-sided retroperitoneal hematoma, and three-dimensional C-arm rotational venography confirmed limb penetration beyond the caval wall. This is the first report of this complication despite two recent studies highlighting the safety profile of this relatively new filter.

Building virtual models by postprocessing radiology images: A guide for anatomy faculty.

Radiology and radiologists are recognized as increasingly valuable resources for the teaching and learning of anatomy. State-of-the-art radiology department workstations with industry-standard software applications can provide exquisite demonstrations of anatomy, pathology, and more recently, physiology. Similar advances in personal computers and increasingly available software can allow anatomy departments and their students to build their own three-dimensional virtual models. Appropriate selection of a data-set, followed by processing and presentation are the key steps in creating virtual models. The construction, presentation, clinical application, and educational potential of postprocessed imaging techniques including multiplanar reformats, minimum intensity projections, segmentation, volume-rendering, surface-rendering, fly-throughs, virtual endoscopy, angiography, and cine-loops are reviewed using examples created with only a personal computer and freeware software. Although only static images are presented in this article, further material is available online within the electronic version of this article. Through the use of basic and advanced image reconstruction and also paying attention to optimized presentation and integration, anatomy courses can be strengthened with appropriate radiological material. There are several key advantages for the anatomy department, which is equipped with the ability to produce virtual models using radiology images: (1) Opportunities to present anatomy using state-of-the-art technology as an adjunct to current practices, (2) a means to forge an improved relationship with the local radiology department, and (3) the ability to create material locally, which is integrated with the local curriculum avoiding the problem of information overload when using the internet or other commercially available resources.

Prophylactic antibiotic guidelines in modern interventional radiology practice.

Modern interventional radiology practice is continuously evolving. Developments include increases in the number of central venous catheter placements and tumor treatments (uterine fibroid therapy, radio- and chemoembolization of liver tumor, percutaneous radiofrequency and cryoablation), and new procedures such as abdominal aortic aneurysm stent-graft repair, vertebroplasty, kyphoplasty, and varicose vein therapies. There have also been recent advancements in standard biliary and urinary drainage procedures, percutaneous gastrointestinal feeding tube placement, and transjugular intrahepatic portosystemic shunts. Prophylactic antibiotics have become the standard of care in many departments, with little clinical data to support its wide acceptance. The rise in antibiotic-resistant strains of organisms in all hospitals worldwide have forced every department to question the use of prophylactic antibiotics. The authors review the evidence behind use of prophylactic antibiotics in standard interventional radiology procedures, as well as in newer procedures that have only recently been incorporated into interventional radiology practice.

Training on a vascular interventional simulator: an observational study.

Radiology registrars were observed performing a left renal artery angioplasty using a proprietary training simulator up to five times during their first year of training. Total procedure time, fluoroscopy times, and metric information from the machine were recorded. Each step of the procedure was judged by an observer and a mistake profile was generated. Fifty-two runs were completed by 12 trainees. The mean procedure time decreased from 16.6 min to 9.8 min over the five runs. The number of mistakes ranged from zero to ten and the mean number of mistakes made varied from 0.7 to 2.6 per procedure without any particular trend. Our study demonstrates that training on the simulator does improve performance. The mistakes made throughout training indicates the potential benefit from further simulator training. It remains unclear how to integrate this form of training in current educational programs.