Abdominal image quality and dose reduction with energy-integrating or photon-counting detectors dual-source CT: A phantom study

PURPOSE

The purpose of this study was to assess image-quality and dose reduction potential using a photon-counting computed tomography (PCCT) system by comparison with two different dual-source CT (DSCT) systems using two phantoms.

MATERIALS AND METHODS

Acquisitions on phantoms were performed using two DSCT systems (DSCT1 [Somatom Force] and DSCT2 [Somatom Pro.Pulse]) and one PCCT system (Naeotom Alpha) at four dose levels (13/6/3.4/1.8 mGy). Noise power spectrum (NPS) and task-based transfer function (TTF) were computed to assess noise magnitude and noise texture and spatial resolution (f50), respectively. Detectability indexes (d') were computed to model the detection of abdominal lesions: one unenhanced high-contrast task, one contrast-enhanced high-contrast task and one unenhanced low-contrast task. Image quality was subjectively assessed on an anthropomorphic phantom by two radiologists.

RESULTS

For all dose levels, noise magnitude values were lower with PCCT than with DSCTs. For all CT systems, similar noise texture values were found at 13 and 6 mGy, but the greatest noise texture values were found for DSCT2 and the lowest for PCCT at 3.4 and 1.8 mGy. For high-contrast inserts, similar or lower f50 values were found with PCCT than with DSCT1 and the opposite pattern was found for the low-contrast insert. For the three simulated lesions, d' values were greater with PCCT than with DSCTs. Abdominal images were rated satisfactory for clinical use by the radiologists for all dose levels with PCCT and for 13 and 6 mGy with DSCTs.

CONCLUSION

By comparison with DSCTs, PCCT reduces image-noise and improves detectability of simulated abdominal lesions without altering the spatial resolution and image texture. Image-quality obtained with PCCT seem to indicate greater potential for dose optimization than those obtained with DSCTs.

Comparison of low-energy virtual monoenergetic images between photon-counting CT and energy-integrating detectors CT: A phantom study

PURPOSE

The purpose of this study was to assess image quality and dose level using a photon-counting CT (PCCT) scanner by comparison with a dual-source CT (DSCT) scanner on virtual monoenergetic images (VMIs) at low energy levels.

MATERIALS AND METHODS

A phantom was scanned using a DSCT and a PCCT with a volume CT dose index of 11 mGy, and additionally at 6 mGy and 1.8 mGy for PCCT. Noise power spectrum and task-based transfer function were evaluated from 40 to 70 keV on VMIs to assess noise magnitude and noise texture (fav) and spatial resolution on two iodine inserts (f50), respectively. A detectability index (d') was computed to assess the detection of two contrast-enhanced lesions according to the energy level used.

RESULTS

For all energy levels, noise magnitude values were lower with PCCT than with DSCT at 11 and 6 mGy, but greater at 1.8 mGy. fav values were higher with PCCT than with DSCT at 11 mGy (8.6 ± 1.5 [standard deviation [SD]%), similar at 6 mGy (1.6 ± 1.5 [SD]%) and lower at 1.8 mGy (-17.8 ± 2.2 [SD]%). For both inserts, f50 values were higher with PCCT than DSCT at 11- and 6 mGy for all keV levels, except at 6 mGy and 40 keV. d' values were higher with PCCT than with DSCT at 11- and 6 mGy for all keV and both simulated lesions. Similar d' values to those of the DSCT at 11 mGy, were obtained at 2.25 mGy for iodine insert at 2 mg/mL and at 0.96 mGy for iodine insert at 4 mg/mL at 40 keV.

CONCLUSION

Compared to DSCT, PCCT reduces noise magnitude and improves noise texture, spatial resolution and detectability on VMIs for all low-keV levels.

How do medical students, residents and graduated physicians really perceive radiologists? A cross-national study

BACKGROUND

Radiology has always been an attractive specialty for residents, but its attractiveness has recently decreased in France regarding the median choice rank after at the National Residency Board.

AIM

To study Radiologists' perceptions and social representations (SRs) among a group of medical students, residents and graduated physicians in France, to better understand the view of Radiologists to debunk stereotypes.

METHODS

The nationwide web-based survey was based on valid hierarchical evocation methods. We determined the corpus's central core and SRs' principal themes with prototypical and correspondence factor analysis (CFA), respectively.

RESULTS

Overall, 419 answers were analyzed. Radiologists' SRs were divided into 3 classes: negative stereotypes of Radiologists, negative stereotypes of the Radiologists' daily practice and Radiologists' skills. After multivariate analysis, variables that seemed to have a positive influence on Radiologists' SRs were considering radiology as a potential choice of specialty (p < 0.001) and the existence of practical experience in Radiology (p = 0.008). Women seemed to have a more negative SR of Radiologists than men (p = 0.035).

DISCUSSION

This was the largest qualitative study on the subject and the only one among medical students, residents and graduated physicians, allowing a global picture. SRs of Radiologists seemed to be negative, potentially caused by poor knowledge of the Radiologists' profession.

CONCLUSION

SRs of Radiologists among medical students and graduated physicians appears to be negative. Promoting the specialty among medical students and encouraging their immersion in a Radiology department could help to debunk many stereotypes about the daily life and missions of Radiologists.

Brain image quality according to beam collimation width and image reconstruction algorithm: A phantom study

PURPOSE

To compare quantitatively and qualitatively brain image quality acquired in helical and axial modes on two wide collimation CT systems according to the dose level and algorithm used.

METHODS

Acquisitions were performed on an image quality and an anthropomorphic phantoms at three dose levels (CTDI_vol: 45/35/25 mGy) on two wide collimation CT systems (GE Healthcare and Canon Medical Systems) in axial and helical modes. Raw data were reconstructed using iterative reconstruction (IR) and deep-learning image reconstruction (DLR) algorithms. The noise power spectrum (NPS) was computed on both phantoms and the task-based transfer function (TTF) on the image quality phantom. The subjective quality of images from an anthropomorphic brain phantom was evaluated by two radiologists including overall image quality.

RESULTS

For the GE system, noise magnitude and noise texture (average NPS spatial frequency) were lower with DLR than with IR. For the Canon system, noise magnitude values were lower with DLR than with IR for similar noise texture but the opposite was true for spatial resolution. For both CT systems, noise magnitude was lower with the axial mode than with the helical mode for similar noise texture and spatial resolution. Radiologists rated the overall quality of all brain images as "satisfactory for clinical use", whatever the dose level, algorithm or acquisition mode.

CONCLUSIONS

Using 16-cm axial acquisition reduces image noise without changing the spatial resolution and image texture compared to helical acquisitions. Axial acquisition can be used in clinical routine for brain CT examinations with an explored length of less than 16 cm.

Inferior mesenteric artery embolization ahead of rectal cancer surgery: AMIREMBOL pilot study

Ischaemic conditioning in rectal cancer surgery by preoperative embolization of the inferior mesenteric artery is feasible and safe. It seems to protect from ischaemic stress during the surgical procedure.

Impact of an artificial intelligence deep-learning reconstruction algorithm for CT on image quality and potential dose reduction: A phantom study

Background

Recently, computed tomography (CT) manufacturers have developed deep‐learning‐based reconstruction algorithms to compensate for the limitations of iterative reconstruction (IR) algorithms, such as image smoothing and the spatial resolution's dependence on contrast and dose levels.

Purpose

To assess the impact of an artificial intelligence deep‐learning reconstruction (AI‐DLR) algorithm on image quality and dose reduction compared with a hybrid IR algorithm in chest CT for different clinical indications.

Methods

Acquisitions on the CT American College of Radiology (ACR) 464 and CT Torso CTU‐41 phantoms were performed at five dose levels (CTDI_vol: 9.5/7.5/6/2.5/0.4 mGy) used for chest CT conditions. Raw data were reconstructed using filtered backprojection, two levels of IR (iDose⁴ levels 4 (i4) and 7 (i7)), and five levels of AI‐DLR (Precise Image; Smoother, Smooth, Standard, Sharp, Sharper). Noise power spectrum (NPS), task‐based transfer function, and detectability index (d′) were computed: d′‐modeled detection of a soft tissue mediastinal nodule (low‐contrast soft tissue chest nodule within the mediastinum [LCN]), ground‐glass opacity (GGO), or high‐contrast pulmonary (HCP) lesion. The subjective image quality of chest anthropomorphic phantom images was independently evaluated by two radiologists. They assessed image noise, image smoothing, contrast between vessels and fat in the mediastinum for mediastinal images, visual border detection between bronchus and lung parenchyma for parenchymal images, and overall image quality using a commonly used four‐ or five‐point scale.

Results

From Standard to Smoother levels, on average, the noise magnitude decreased (for all dose levels: −66.3% ± 0.5% for mediastinal images and −63.1% ± 0.1% for parenchymal images), the average NPS spatial frequency decreased (for all dose levels: −35.3% ± 2.2% for mediastinal images and −13.3% ± 2.2% for parenchymal images), and the detectability (d′) of the three lesions increased. The opposite pattern was found from Standard to Sharper levels. From Smoother to Sharper levels, the spatial resolution increased for the low‐contrast polyethylene insert and the opposite for the high‐contrast air insert. Compared to the i4 used in clinical practice, d′ values were higher using Smoother (mean for all dose levels: 338.7% ± 29.4%), Smooth (103.4% ± 11.2%), and Standard (34.1% ± 6.6%) levels for the LCN on mediastinal images and Smoother (169.5% ± 53.2% for GGO and 136.9% ± 1.6% for HCP) and Smooth (36.4% ± 22.1% and 24.1% ± 0.9%, respectively) levels for parenchymal images. Radiologists considered the images satisfactory for clinical use at these levels, but adaptation to the dose level of the protocol is required.

Conclusion

With AI‐DLR, the smoothest levels reduced the noise and improved the detectability of chest lesions but increased the image smoothing. The opposite was found with the sharpest levels. The choice of level depends on the dose level and type of image: mediastinal or parenchymal.

CHAIMELEON Project: Creation of a Pan-European Repository of Health Imaging Data for the Development of AI-Powered Cancer Management Tools

The CHAIMELEON project aims to set up a pan-European repository of health imaging data, tools and methodologies, with the ambition to set a standard and provide resources for future AI experimentation for cancer management. The project is a 4 year long, EU-funded project tackling some of the most ambitious research in the fields of biomedical imaging, artificial intelligence and cancer treatment, addressing the four types of cancer that currently have the highest prevalence worldwide: lung, breast, prostate and colorectal. To allow this, clinical partners and external collaborators will populate the repository with multimodality (MR, CT, PET/CT) imaging and related clinical data. Subsequently, AI developers will enable a multimodal analytical data engine facilitating the interpretation, extraction and exploitation of the information stored at the repository. The development and implementation of AI-powered pipelines will enable advancement towards automating data deidentification, curation, annotation, integrity securing and image harmonization. By the end of the project, the usability and performance of the repository as a tool fostering AI experimentation will be technically validated, including a validation subphase by world-class European AI developers, participating in Open Challenges to the AI Community. Upon successful validation of the repository, a set of selected AI tools will undergo early in-silico validation in observational clinical studies coordinated by leading experts in the partner hospitals. Tool performance will be assessed, including external independent validation on hallmark clinical decisions in response to some of the currently most important clinical end points in cancer. The project brings together a consortium of 18 European partners including hospitals, universities, R&D centers and private research companies, constituting an ecosystem of infrastructures, biobanks, AI/in-silico experimentation and cloud computing technologies in oncology.

A new clinical approach to improve the appropriate use of peripherally inserted central catheters: a prospective study

OBJECTIVES

Peripherally inserted central catheters (PICCs) are central venous catheters commonly used for administration of chemotherapy, prolonged antibiotic treatment, or parenteral nutrition. It is advisable to use the PICC with the fewest lumens and the smallest possible diameter to reduce major complications. A pharmaceutical analysis and validation of PICC requests was designed to improve efficiency and patient safety. The aim of this study was to evaluate the impact of pharmaceutical interventions (PIs) by the clinical pharmacist in the PICC process.

METHODS

A prospective pilot study was conducted in a French university hospital. Four categories of PIs were defined according to the different stages of the PICC insertion process: before insertion to validate with the physician the relevance of the request and the choice of PICC model (PI applicant); during insertion (PI installer); during usage by nurses for analysis of drug incompatibilities (PI user); and at hospital discharge for reassessment of the device maintenance (PI reassessment). Each PI applicant was designated a potential harm from 1 to 4, with a cut-off of 2 representing harm for the patient.

RESULTS

Over 6 months, 277 requests were analysed and 297 PIs were completed (109 applicants, 98 installers, 84 users, and 6 PIs for reassessment). The acceptance rate by the physicians was 93.6%. 52% of the PI applicants had a potential harm of 2 or more. 5% of PICC requests were refused by the pharmacist due to an inappropriate choice of device. A total of 207 (74.7%) of the requests analysed by the clinical pharmacist led to insertion.

CONCLUSIONS

The implementation of a clinical pharmacy activity applied to PICC requests analysis and validation leads to improved patient care by securing the PICC circuit. This analysis demonstrates the beneficial role of the clinical pharmacist in PIs associated with medical devices.

Performance of four dual-energy CT platforms for abdominal imaging: a task-based image quality assessment based on phantom data

OBJECTIVES

To compare the spectral performance of dual-energy CT (DECT) platforms using task-based image quality assessment based on phantom data.

MATERIALS AND METHODS

Two CT phantoms were scanned on four DECT platforms: fast kV-switching CT (KVSCT), split filter CT (SFCT), dual-source CT (DSCT), and dual-layer CT (DLCT). Acquisitions on each phantom were performed using classical parameters of abdomen-pelvic examination and a CTDI_vol at 10 mGy. Noise power spectrum (NPS) and task-based transfer function (TTF) were evaluated from 40 to 140 keV of virtual monoenergetic images. A detectability index (d') was computed to model the detection task of two contrast-enhanced lesions as function of keV.

RESULTS

The noise magnitude decreased from 40 to 70 keV for all DECT platforms, and the highest noise magnitude values were found for KVSCT and SFCT and the lowest for DSCT and DLCT. The average NPS spatial frequency shifted towards lower frequencies as the energy level increased for all DECT platforms, smoothing the image texture. TTF values decreased with the increase of keV deteriorating the spatial resolution. For both simulated lesions, higher detectability (d' value) was obtained at 40 keV for DLCT, DSCT, and SFCT but at 70 keV for KVSCT. The detectability of both simulated lesions was highest for DLCT and DSCT.

CONCLUSION

Highest detectability was found for DLCT for the lowest energy levels. The task-based image quality assessment used for the first time for DECT acquisitions showed the benefit of using low keV for the detection of contrast-enhanced lesions.

KEY POINTS

• Detectability of both simulated contrast-enhanced lesions was higher for dual-layer CT for the lowest energy levels. • The image noise increased and the image texture changed for the lowest energy levels. • The detectability of both simulated contrast-enhanced lesions was highest at 40 keV for all dual-energy CT platforms except for fast kV-switching platform.

Image quality and dose reduction opportunity of deep learning image reconstruction algorithm for CT: a phantom study

OBJECTIVES

To assess the impact on image quality and dose reduction of a new deep learning image reconstruction (DLIR) algorithm compared with a hybrid iterative reconstruction (IR) algorithm.

METHODS

Data acquisitions were performed at seven dose levels (CTDI_vol : 15/10/7.5/5/2.5/1/0.5 mGy) using a standard phantom designed for image quality assessment. Raw data were reconstructed using the filtered back projection (FBP), two levels of IR (ASiR-V50% (AV50); ASiR-V100% (AV100)), and three levels of DLIR (TrueFidelity™ low, medium, high). Noise power spectrum (NPS) and task-based transfer function (TTF) were computed. Detectability index (d') was computed to model a large mass in the liver, a small calcification, and a small subtle lesion with low contrast.

RESULTS

NPS peaks were higher with AV50 than with all DLIR levels and only higher with DLIR-H than with AV100. The average NPS spatial frequencies were higher with DLIR than with IR. For all DLIR levels, TTF_50% obtained with DLIR was higher than that with IR. d' was higher with DLIR than with AV50 but lower with DLIR-L and DLIR-M than with AV100. d' values were higher with DLIR-H than with AV100 for the small low-contrast lesion (10 ± 4%) and in the same range for the other simulated lesions.

CONCLUSIONS

New DLIR algorithm reduced noise and improved spatial resolution and detectability without changing the noise texture. Images obtained with DLIR seem to indicate a greater potential for dose optimization than those with hybrid IR.

KEY POINTS

• This study assessed the impact on image quality and radiation dose of a new deep learning image reconstruction (DLIR) algorithm as compared with hybrid iterative reconstruction (IR) algorithm. • The new DLIR algorithm reduced noise and improved spatial resolution and detectability without perceived alteration of the texture, commonly reported with IR. • As compared with IR, DLIR seems to open further possibility of dose optimization.

Noise assessment across two generations of iterative reconstruction algorithms of three manufacturers using bone reconstruction kernel

PURPOSE

To compare the noise-magnitude and noise-texture obtained using strong kernel across two generations of iterative reconstruction (IR) algorithms proposed by three manufacturers.

MATERIALS AND METHODS

Five computed tomography (CT) systems equipped with two generations of IR algorithm (hybrid/statistical IR [H/SIR] or full/partial model-based IR [MBIR]) were compared. Acquisitions on Catphan 600 phantom were performed at 120kV and three dose levels (CTDI_vol: 3, 7 and 12mGy). Raw data were reconstructed using standard "bone" kernel for filtered back projection and one iterative level of two generations of IR algorithms. Contrast-to-noise ratio (CNR) was computed using three regions of interest placed semi-automatically: two placed in the low-density polyethylene and Teflon inserts and another placed on the solid water. Noise power spectrum (NPS) was computed to assess the NPS-peak and noise-texture.

RESULTS

CNR was significantly greater in MBIR compared to H/SIR algorithms for all CT systems (P<0.01). CNR were improved on average from H/SIR to MBIR of 36±14% [SD] (range: 24-57%) for GE-Healthcare, 109±19 [SD] % (range: 89-139%) for Philips Healthcare and 42±5 [SD] % (range: 36-47%) for Siemens Healthineers. The mean NPS peak decreased from H/SIR to MBIR by -41±6 [SD] % (range: -47--35%) for GE Healthcare, -79±3 [SD] % (range: -82--76%) for Philips Healthcare and -52±2 [SD] % (range: -54--51%) for Siemens Healthineers systems. NPS spatial frequencies were greater with MBIR than with H/SIR for Philips Healthcare (20 ± 2 [SD] %; range: 19-22%) and for Siemens Healthineers (9±5 [SD] %; range: 4-14%) but lower for GE Healthcare (-17±3 [SD] %; range: -14--20%).

CONCLUSION

Using bone kernel with recent MBIR algorithms reduces the noise-magnitude for all CT systems assessed. Noise texture shifted towards high frequency for Siemens Healthineers and Philips Healthcare but the opposite for GE Healthcare.

PICC management led by technicians: Establishment of a cooperation program with radiologists and evaluation of complications

PURPOSE

The purpose of this study was to evaluate a cooperation program in order to compare incidence of complications after peripherally inserted central catheter (PICC) placement between radiologists and technicians.

MATERIALS AND METHODS

PICC placement technique was standardized with ultrasound-guided puncture and fluoroscopic guidance. Numbers of PICC delegated to technicians, and PICC placement difficulties, were prospectively recorded for the whole study population whereas complications such as PICC infection, deep venous thrombosis and catheter occlusion were prospectively recorded until PICC removal for a subgroup of patients included during one month.

RESULTS

A total of 722 patients had PICC placement. There were 382 men and 340 women with a mean age of 66.8±15.8 (SD) years (range: 18-94years); of these, 442/722 patients (61.22%) were included in the cooperation program with 433/722 patients (59.97%) who effectively had PICC placement by technicians and 289/722 (40.03%) by radiologists. Technicians needed radiologists' help for 23/442 patients (5.20%) including 6 failed PICC placement subsequently performed by radiologists. Twenty complications (20/77; 26%) were recorded in the subgroup of 77 patients studied for complications. No differences in complications rate were found between the 33 patients who underwent PICC placement by radiologists (6/33; 18%) and the 44 patients who underwent PICC placement by technicians (14/44; 32%) (P=0.296). Complications included 8 PICC-related infections (8/77; 10.4%), 3 deep venous thromboses (3/77; 3.9%) and 9 catheter occlusions (9/77; 11.7%).

CONCLUSION

PICC placement led by technicians is feasible and safe without statistical difference in terms of complications compared to PICC placement made by radiologists.

Ultrasound-guided vacuum-assisted breast biopsy with a small-caliber device: A multicenter consecutive study of 162 biopsied lesions

Objective:

In this study, we aimed to analyze technical and diagnostic potential, and safety of the small-caliber vacuum-assisted biopsy (SCVAB) device in a multicenter consecutive study taking into consideration the type and location of breast lesion.

Methods:

We collected data from 5 breast imaging centers where radiologists used the SCVAB device for biopsies in 162 patients. We analyzed the conditions for using the SCVAB device according to the characteristics of the lesions, the volume of excision, and the analyzability obtained by biopsy samples.

Results:

The biopsies of 80 circumscribed masses, 61 complex lesions, and 24 microcalcification foci were included in the study. The reasons for choosing SCVAB as an initial technique were identified. A total of 47 lesions were removed with SCVAB; among them, 24 lesions were initially chosen for total excision. SCVAB was used as a second-choice biopsy method after core-needle biopsy failure in 20 cases. If SCVAB had not been available, vacuum-assisted biopsy would have been the most frequently used technique (106 under ultrasound, and 18 under stereotactical guidance).

Conclusions:

The SCVAB system is an alternative to classical vacuum biopsy, enabling representative samples to be obtained from lesions that are difficult to access, complex, small, or in cases of unsuccessful previous biopsy. The SCVAB system was determined as the chosen technique by the radiologists in this study due to feasibility, ergonomics and absence of side effects detected in this study.

Assessment of Patient's Peak Skin Dose Using Gafchromic Films During Interventional Cardiology Procedures: Routine Experience Feedback

To assess the interest of Gafchromic films in detection of patient's peak skin dose (PSD) in interventional cardiology. A prospective study of 112 patients was conducted (July-December 2015). Three diagnostic and therapeutic procedures were evaluated: coronary angiography (CA), coronary angiography and coronary angioplasty for one or two vessels disease (CA-PTCA) and coronary angioplasty of complex chronic total occlusion (CTO). Dosimetric indicators (DIs) were collected and PSD were measured with Gafchromic films. Dose distribution was evaluated within 10 'Thorax Body-zone' defined by the system. Correlations between PSD and DI or dose distribution were computed. Delivered dose increased in complex procedures. The PSD were 0.121 ± 0.063 Gy for CA, 0.256 ± 0.142 Gy for CA-PTCA and 1.116 ± 0.721 Gy for CTO. High correlations were observed for PSD and DI as well for dose distribution within the 'Thorax Body-zone'. Film dosimetry is suggested for CTO procedures since the threshold of 2 Gy for skin injuries is likely to be exceeded.

Diffusion-weighted MRI, dynamic susceptibility contrast MRI and ultrasound perfusion quantification of denervated muscle in rabbits

OBJECTIVE

The purpose of this study was to assess denervated muscle perfusion using dynamic susceptibility contrast MRI (DSCMRI) and contrast-enhanced ultrasound (CEUS), and to measure denervated muscle apparent diffusion coefficient (ADC) on b1000 diffusion-weighted MRI (DWMRI) at 3 T in order to clarify whether muscle denervation leads to an increase in the extracellular extravascular space, or an increase in blood flow-or both.

MATERIALS AND METHODS

Axotomy of the right sciatic nerve of six white rabbits was performed at day 0. At day 9, hind limb muscles MRI and CEUS were performed to assess the consequences of denervation and both semimembranosus muscles of each rabbit were explanted for histological studies. Signal intensity on T2- and T1-weighted MRI, ADC on DWMRI, maximum signal drop (MSD) on DSCMRI and the area under the curve (AUC) on CEUS were measured over circular regions of interest (ROI), in both semimembranosus muscles. Non-parametric Wilcoxon matched-pairs tests were used to assess the mean differences between denervated and normal muscles.

RESULTS

T2 fat-saturated (FS) MRI studies showed a strong signal in the right semimembranosus muscles compared with the left side, and gadolinium enhancement was observed on T1 FS MRI. Denervated muscles show a significant increase in ADC on DWMRI (p < 0.01) and a significant signal enhancement on DSCMR imaging (p < 0.05) and on first-pass CEUS (p < 0.05).

CONCLUSION

The results of this study--based on perfusion- and diffusion-weighted images--suggest that, after denervation, both increased blood flow through muscle tissue and expansion of the extracellular water volume are present.

[Virtual interventional radiology: evaluation of performances as a function of experience]

PURPOSE

To determine the value of an angioplasty simulation to differentiate the users based on their level of experience. To determine the perceived usefulness of an angioplasty simulation program.

MATERIALS AND METHODS

Forty-six radiologists performed a renal angioplasty on a VIST simulator (Mentice Corporation, Gothenburg, Sweden); the procedure was completed by 41 radiologists. The radiologists were divided into two groups based on the level of experience. Quantitative variables analyzed included procedure duration time and fluoroscopy time. The radiologists then completed a questionnaire evaluating the simulation program.

RESULTS

Radiologists with more than 2 years of clinical experience (n=14) performed the procedures faster (20.4 min vs 27.4 min, p<0.01) using less fluoroscopy time (7.8 min vs 11.2 min, p<0.05) than others. Radiologists performing more than 2 procedures per month (n=14) performed the procedures faster (19.4 min vs 27.9 min, p<0.01) using less fluoroscopy time (7.4 min vs 11.3 min, p<0.05) than other (n=27). The participating radiologists indicated that the simulation was realistic.

CONCLUSION

Procedure duration time and duration of fluoroscopy were criteria able to differentiate the users based on their level of experience. The educational value of the simulation program was perceived as helpful by the users.

[Contrast enhanced MR angiography: evolving towards whole-body real time acquisitions]

MRA includes all techniques used to depict vessels with MR. Gadolinium contrast injection combined with gradient echo sequences is the technique of choice for vascular imaging. Technical advances now allow faster acquisitions. The purpose of this article is to present two main advances with MRA: whole-body MRA and dynamic 3D MRA. Technical considerations, acquisition techniques, advantages and pitfalls based on our experience with a 1.5T MR unit will be discussed in order to promote their use in routine clinical practice.

Characterisation of peripartum cardiomyopathy by cardiac magnetic resonance imaging

Peripartum cardiomyopathy (PPCM) is a rare cause of heart failure. Only half of the patients recover normal cardiac function. We assessed the usefulness of magnetic resonance imaging (MRI) and late enhancement imaging to detect myocardial fibrosis in order to predict cardiac function recovery in patients with peripartum cardiomyopathy. Among a consecutive series of 1,037 patients referred for heart failure treatment or prognostic evaluation between 1999 and 2006, eight women had confirmed PPCM. They all underwent echocardiography and cardiac MRI for assessment of left ventricular anatomy, systolic function and detection of myocardial fibrosis through late enhancement imaging. Mean (+/- SD) baseline left ventricular ejection fraction (LVEF) was 28 +/- 4%. After a follow-up of 50 +/- 9 months, half the patients recovered normal cardiac function (LVEF = 58 +/- 4%) and four did not (LVEF = 35 +/- 6%). None of the eight patients exhibited abnormal myocardial late enhancement. No difference in MRI characteristics was observed between the two groups. Patients with PPCM do not exhibit a specific cardiac MRI pattern and particularly no myocardial late enhancement. It suggests that myocardial fibrosis does not play a major role in the limitation of cardiac function recovery after PPCM.

Non-randomized, prospective, multi-centre evaluation of the ABSOLUTE .035 peripheral self-expanding stent system for occluded or stenotic superficial femoral or proximal popliteal arteries (ASSESS Trial): acute and 30-day results

AIM

The aim of the paper was to investigate the performance of the ABSOLUTE .035 Peripheral Self-Expanding Stent System in preventing restenosis of superficial femoral or proximal popliteal arteries. Due to a lack of large controlled trials proving its long-term durability femoropopliteal artery stenting is still a matter of debate. In this paper we report the study design, the acute and short-term results of a prospective European registry on the treatment of TASC B and C femoropopliteal lesions with the use of the ABSOLUTE stent.

METHODS

This prospective, non-randomized, multi-centre study enrolled 122 patients with symptomatic peripheral occlusive disease at 14 sites in Europe. Patients were included with obstructed femoropopliteal arteries. Key inclusion criteria were de novo lesions > or = 4.0 mm and < or = 7.0 mm in diameter, and > or = 40 mm and < or = 200 mm in length. Single target vessel treatment had to be performed with a maximum of three stents.

RESULTS

Mean target lesion length was 108 +/- 44 mm (range 22.2 to 200 mm) and mean reference vessel diameter 4.6 +/- 0.8 mm by quantitative angiography; 71% of the lesions analyzable by quantitative angiography (QA) had total occlusions. A total of 227 stents were implanted, 224 of which were deployed successfully (98.7%). Mean percentage of diameter stenosis was reduced from 90.9 +/- 15.5 % (range 41.3 to 100) to 19.0 +/- 8.4% (range 2.3 to 41.5). Device and procedural success were 83.6% each whereas technical success reached 100%. Sixteen lesions had a > or = 30% residual stenosis post-procedure, 6 of them (37.5%) rated as being calcified. Eleven patients experienced major complications (9.1%) and 6 patients experienced minor complications (5%) within 30 days. Duplex ultrasound based 1-month restenosis rate was 9.3%. Target lesion revascularization (TLR) and target vessel revascularization (TVR) rates were 0.8% and 1.7%, respectively and amputation rate was 0.8%. Mean ankle-brachial index (ABI) at rest and after exercise increased significantly from baseline to 30 days follow-up by 0.63 +/- 0.20 to 0.94 +/- 0.17 and from 0.44 +/- 0.23 to 0.85 +/- 0.21, respectively (P<0.001 each).

CONCLUSION

The treatment of TASC B and C femoro-popliteal lesions with use of the ABSOLUTE stent is safe and feasible. Short-term follow-up documents persistent improvement of hemodynamics. The 6- and 12-month data have to be awaited for further conclusions:

[The best of vascular medicine in 2006]

Peripheral arterial disease (PAD) remains an under-diagnosed affection, and the ankle-brachial index (ABI), a simple diagnostic method, is poorly known and seldom used, and the vascular patient's prescription list is frequently insufficient regarding results obtained in large trials with good methodology. The French ATTEST study underlines the fact that ABI is measured in less than 1 out of 3 patients with PAD. In ATTEST study, less than 10% have the triple therapy validated in PAD : antiplatelet drugs, statins and ACE-inhibitors. The international REACH registry included more than 60 000 patients suffering from atherosclerosis, including 8 000 cases with PAD. This survey evidences that in PAD patients, the annual cardiovascular complication rate is significantly higher than in patients with coronary artery disease (18 vs 13%); again PAD appears systematically under-treated when compared to CAD. These epidemiological surveys highlight the importance of screening of atherosclerotic lesions with the aim of setting an active prevention of CV complications. The new guidelines insist on the screening of PAD in patients at risk, as well as on the importance of the global management after initiating the triple therapy, independent of the CV risk factors. In a 5-year longitudinal study from an initial cohort of 2265 subjects, Aboyans et al. studied the progression of PAD by repeated measurements of ABI at the level of ankles and toes. Factors of progression for large-vessels PAD were active smoking, the total/HDL-cholesterol ratio, Lp(a) and CRP. Importantly, diabetes was not associated to the PAD progression in large vessels, but in contrast, it was the sole factor associated to the progression of PAD in small vessels. In an Austrian study published this year in the NEJM, Schillinger et al. compared balloon angioplasty versus the use of Nitinol stent for the treatment of long stenoses of the superficial femoral artery. In case of claudication, these lesions are usually treated medically, whereas surgery is required for more severe cases. The fact that stenting these long lesions of the superficial femoral artery provides benefits in terms of restenosis opens a approach for the endovascular therapy, to be confirmed by larger trials.

[Usefulness of magnetic resonance angiography in the screening of renal artery stenosis in hypertensive patients: proposition of a diagnostic algorithm: a study of 245 patients]

Usefulness of magnetic resonance angiography in the screening of renal artery stenosis in hypertensive patients: proposition of a diagnostic algorithm: a study on 245 patients. Different non-invasive techniques, including Duplex, spiral angioscan, and magnetic resonance angiography (MRA) are available for the diagnosis of renal artery stenosis (RAS). The aim of this study was to assess the diagnostic performances of MRA and the MRA-Duplex couple in the diagnosis of RAS. Between September 2003 and January 2005, 245 patients benefited from a renal MRA for the assessment of hypertension etiology. The MRA-Duplex couple was performed in 228 patients. Renal arteriography was performed in case of abnormalities observed with MRA and/or Duplex (n=41). The sensitivity and specificity of MRA were respectively at 100% and 23%. The sensitivity was notably higher in the right renal artery (100 vs. 73%). The sensitivity and specificity of Duplex were respectively at 71 and 85%. The concordance between the two exams was disappointing (kappa at 0.39 for the right side and 0.62 for the left side), leading to the interest of the MRA-Duplex association for excluding the presence of RAS (sensitivity and negative predictive value=100%). However, using the MRA-Duplex couple led to a high number of false positive cases, due to MRA, leading to 11 angiograms out of 41 exams, without any significant RAS. In case of suspicion of RAS, the MRA-Duplex couple permits to exclude definitely the diagnosis of RAS. In case of discordance between the 2 exams, it would be useful to require a spiral angioscan and/or redo a Duplex exam using contrast agents, prior to angiography with a therapeutic goal. These management modalities might be useful to avoid the number of normal angiograms, with an inherent risk of complications and cost excess.

[The best of vascular medicine in 2005]

It is illusory to think that one year is long enough to establish all the truths that will guide our clinical practice in vascular medicine. On the contrary, one year was long enough to contradict what the preceding twelve months had set out to demonstrate. Consequently, promising trials in the treatment of abdominal aortic aneurysms by endoprostheses have been the object of contradictory debate with regards to the long-term benefits. In fundamental research, circulating progenitors of endothelial cells have been shown to be a marker of atherosclerosis, but is it a better marker than LDL-cholesterol values? The demonstration that these progenitors are of value in the treatment of essential ischaemia of the lower limbs is awaited. Finally, ximelagatran, a direct thrombin antagonist, seemed to have all the qualities of an ideal anticoagulant: easy to use, safe... until the report of raised hepatic enzymes, the clinical relevance of which remains to be determined. In the good news section: the Systolic Pressure Index, an unquestioned marker of arterial disease. Its reduction was known to be correlated with the prevalence of cardiovascular complications. However, it has now been shown that an increase in the index is also associated with cardiovascular complications, a real U-shaped curve. Renal arterial stenosis should be considered in patients with left ventricular failure presenting with flash pulmonary oedema. In the absence of cardiac pathology, BNP would seem to be a good biological marker of haemodynamically significant renal arterial stenosis. Finally, should superficial femoral artery stenosis be treated by an active stent. To date, there is no formal proof.

[Tako-tsubo syndrome and left ventricular obstruction: report of one case]

We report here the case of an 80 year old female suffering from Tako-tsubo syndrome diagnosed following type B aortic dissection, treated surgically with an aortic endoprosthesis. The recovery was marked by the secondary development of left intraventricular obstruction. Regression of the electrical and ultrasound anomalies was slow, taking 4 months of treatment with a beta-blocker. The intraventricular obstruction seemed to occupy a central role in this case, and we discuss the significance of this mechanical phenomenon in the pathophysiology of this syndrome.

Low-profile Stent System for Treatment of Atherosclerotic Renal Artery Stenosis: The GREAT Trial

PURPOSE

The Palmaz Genesis Peripheral Stainless Steel Balloon Expandable Stent in Renal Artery Treatment (GREAT) Trial was designed to assess the safety and performance of a low-profile stent for the treatment of obstructive renal artery disease by looking at 6-month renal artery patency uniformly analyzed by a Core Lab.

MATERIALS AND METHODS

Fifty-two consecutive patients (mean age, 63.7 years) were successfully treated with the Palmaz Genesis Peripheral Stent (Cordis, Miami, FL) on the Slalom 0.018-inch Delivery System (Cordis Europe N.V., Oosteinde 8, NLO-9301 LJ Roden, The Netherlands) at 11 investigational centers. Patients with severe renal failure and > 8-mm renal artery were excluded. Primary endpoint was angiographic determination of in-stent percent diameter stenosis at 6 months. Fifty-one patients were treated with one stent, one patient was treated with two stents to cover the complete lesion.

RESULTS

Mean percentage diameter stenosis before renal angioplasty was 68.2% +/- 12.0%. No stent implantation failure, displacement, need for additional stent implantation, or procedural complication was observed. Six-month angiography was performed in 41 of 52 patients (79%) resulting in a mean in-stent percent diameter stenosis or Quantitative Vessel analysis (QVA) at 6 months of 23.9%. The in-stent binary (percent diameter stenosis > 50%) restenosis rate at 6 months was 14.3%. No fatal events occurred up to 6 months after implantation. Major adverse events occurred in five patients: four patients (7.7%) required a revascularization and one patient (1.9%) experienced a cerebrovascular event, which regressed spontaneously.

CONCLUSIONS

The Palmaz Genesis stent (Cordis) provides good results for renal artery stent placement, with an in-stent binary restenosis rate (percent diameter stenosis > 50%) at 6 months of 14.3% as determined with angiography.

Imaging of aortic dissection by helical computed tomography (CT)

Aortic dissection is the most frequent cause of aortic emergency, and its outcome is still frequently fatal. The management of this pathology has changed with the development of endovascular means. Nowadays, imaging modalities are helpful in management decision-making by providing information such as identification of entry tears along the aorta and involvement of the visceral branches of the abdominal aorta. Multi-slice CT scanning now appears to be the modality of choice for complete examination of the entire aorta. We review the parameters of image acquisition and contrast injection; appearances on CT of acute and chronic dissection are illustrated. Diagnostic pitfalls in CT imaging of acute dissection are discussed. Imaging of the post-surgical aorta and of chronic dissection is outlined. Intra-mural hematoma and penetrating aortic ulcer are subtypes of aortic dissection, and their appearances on CT scanning are also presented.

[Clinic and morphologic evolution five years after a renal atherosclerotic artery stenosis (RAS): a study of twenty nine hypertensive patients population]

The indication of renal atherosclerotic artery stenosis revascularisation is always debated in clinical practices when arterial hypertension is stabilized by the treatment, especially if the stenosis is discovered fortuitously. The clinician needs clinical and morphological markers which will indicate or not the revascularisation in the situation of "nephronic protection". The benefits of angioplasty have been studied on the blood pressure, the creatinine clearance, the glomerular function analyzed by scintigraphy, the renal length and more recently on the mean cortical thickness (MCT). The follow-up of these studies is generally inferior to 2 years. In this work, we tried to estimate the clinic and morphologic evolution 5 years after a unilateral artery stenosis angioplasty. From a group of 249 patients who had a renal angioplasty between January 1995 and January 2000 (T0), 29 patients with refractory hypertension and with a unilateral atherosclerotic renal artery stenosis on spiral computed tomographic angiography (TCA) performed at T0 [17 M; 12 W; medium age 68.6 +/- 10 years] were included. The TCA performed at 5 years (T5) eliminated a new renal arterial stenosis or restenosis. We have analyzed 29 revascularized kidneys (kidney S) and 29 controlateral kidneys (kidney C), the blood pressure and renal function. The renal length (mm) was at T0: kidney C=99.4 +/- 13.5; kidney S=93.5 +/- 10.8 and at T5: kidney C=99.4 +/- 12.6; kidney S=94.2 +/- 10.7. MCT (mm) was at T0: kidney C=7 +/- 1.2; kidney S=6.6 +/- 1.1 and at T5: kidney C=6.2 +/- 1.2; kidney S5=6 +/- 1. The cortical atrophy got worse while the renal length and creatinine clearance were stable: only diastolic blood pressure was controlled (78.8 mmHg +/- 11.9). In spite of small strength, this study arguments the fact that the angioplasty isn't sufficient to control the arterial hypertension in an atheromatous context, not allowing to slow the evolution of distal cortical lesions with however a stability of creatinine clearance.

Quand, comment et pourquoi réaliser une exploration des artères rénales ?

The objectives of this course are both: to describe acquisition, injection and reconstruction parameters of volumic images for renal arteries examination and specific signs; to discuss the role of the different images in the diagnosis and in the therapeutic management. Ultrasound is one of the best imaging for the analysis of renal arteries in the detection of stenosis even if the sensitivity is less (around 85%)compared to CT Angiography (95%) and MR Angiography (90%). Because of this advantage and of 3D evaluation, CTA and MRA are sometimes in the first line for renal artery evaluation and can assess morphology before angioplasty. Renal scintigraphy with Captopril test and renin dosage are only used for small kidney evaluation. Arteriogram is systematically followed by angioplasty if possible. With the new endovascular materials, complications decrease (less than 5% with a major reduction in cholesterol emboli) and indications of endoprosthesis increase (71% of stenting with half of it in direct stenting technique). This course will give practical tools for imaging acquisition, specifically 3D imaging, for indications and management of lesion in accordance to symptoms and morphology.

Iatrogenic iliac artery rupture and type a dissection after endovascular repair of type B aortic dissection

We report a case of two iatrogenic complications after endovascular repair of a type B aortic dissection treated for abdominal aortic branch ischemia. A rupture of the common iliac artery occurred first during the procedure. A type A dissection occurred 12 days later. The proximal part of the aortic endovascular graft had created a tear in the aortic wall resulting in a retrograde type A dissection. Although aortic endovascular grafting is apparently associated with less morbidity and mortality, potentially lethal complications, both acute and delayed, may arise.

Risk factors of early and late complications in patients undergoing endovascular aneurysm repair

OBJECTIVES

to identify pre-operative factors that could predict complications following from transluminal repair of abdominal aortic aneurysms (AAA).

METHODS

during a 5-year period, 96 consecutive patients underwent elective endovascular treatment of a AAA. In all patients, helical CT and/or Magnetic Resonance Imaging (MRI), and plain abdominal roentgenogram were performed at 1, 3, 6, 12, 18, and 24 months and yearly thereafter. Angiography was performed systematically 1 year after the stent-graft implantation, or earlier if helical CT or MRI diagnosed an increase in the maximal transverse diameter or a high flow endoleak.

RESULTS

early (<30 days) morbidity (12%) was significantly increased by pre-operative renal insufficiency (p < 0.01). Early mortality (2%) correlated with ASA score (p = 0.01). Median follow-up was 27 months (range 3-66). Mortality (12%) during follow-up was correlated to the pre-operative coronary status (p = 0.01). A type I endoleak was diagnosed in 18 patients (19%). Common iliac artery diameter was correlated with the presence of type I endoleak (p < 0.001). A type II endoleak was diagnosed in 47 (49%) patients. The diagnostic of type II endoleak was significantly increased (p = 0.001) in patients with pre-operative patent IMA associated with more than four patent lumbar arteries. The anatomic characteristics of the aneurysm were correlated to the additional endovascular procedures during stentgraft implantation (p = 0.01), and to the implantation of a complementary iliac limb extension during follow-up (p = 0.01).

CONCLUSIONS

the risk factors determined by this statistical analysis could help surgeons to select more accurately patients suitable for endovascular treatment.

Percutaneous endovascular treatment for stenoses and occlusions of infrarenal aorta and aortoiliac bifurcation: midterm results

OBJECTIVE

evaluation and comparison of the endovascular treatment of isolated aortic and aortoiliac atherosclerotic lesions (stenoses and occlusions).

METHODS

a percutaneous endovascular procedure was performed in 52 patients (38 men and 14 women) with a mean age of 52 years (range, 25-85 years). The baseline angiogram showed 35 aortic lesions (31 stenoses, 4 occlusions) and 17 aortoiliac lesions (14 stenoses, 3 occlusions). Percutaneous techniques used in this series included variable combinations of transluminal angioplasty and stenting. All stents placements were performed over-the-wire using the transfemoral route (most often bilateral approach). Clinical examination and Duplex-scan were performed at discharge, 1 month, 6 months, 12 months, and then yearly.

RESULTS

technical success was 100% for aortic and aortoiliac lesions. Angiographic success rates were comparable for aortic (91%) and aortoiliac (94%) lesions. No death occurred during or early after the endovascular intervention. Duplex-scan confirmed 100% patency rate at discharge. There was no significant difference between the aortic (94%) and aortoiliac (96%) groups regarding immediate clinical improvement. Mean follow-up was 34+/-31 months (range, 0-130 months). The cumulative primary patency rate at 36 months was 85% in the aortic group and 86% in the aortoiliac group. Clinical success, defined as a symptom-free status at the end of follow-up, was also similar in both groups.

CONCLUSION

endovascular treatment of isolated aortic lesions of the infra-renal aorta has favorable outcomes comparable to those of aortoiliac lesions.

Stent-graft repair of the thoracic aorta: short-term results

The purpose of this study was to evaluate clinical feasibility and immediate outcome of stent-graft repair of the thoracic aorta. From December 1999 to January 2001, a total of 14 patients underwent stent-graft repair of the thoracic aorta. The underlying etiologies were traumatic rupture of the aortic isthmus in four cases, Stanford type B dissection in four, thoracic aortic aneurysm in three, penetrating atherosclerotic ulcer in two cases, and postoperative aortoesophageal fistula in one case. Stent-graft placement was performed under angiographic control in all cases in association with transesophageal echography in seven cases. The procedure was performed under emergency conditions in five cases. Thirteen patients presented contraindications for surgery. Stent-graft placement was successful in all cases. No further surgery has been performed in any case. Thus we conclude that endovascular treatment of the thoracic aorta using stent grafts is a promising therapeutic modality in patients with contraindications for conventional surgical treatment.

[Important of magnetic resonance angiography with gadolinium injection in pulmonary vein diseases]

The study of the pulmonary veins by echocardiography is sometimes difficult especially when the ultrasonic window is restricted. Conventional angiography is the classic reference examination but it exposes the patient to ionising radiation and requires the injection of an iodine contrast product. Another technique that can provide the essential information is magnetic resonance angiography (MRA) with injection of gadolinium. It was performed in 9 patients for suspected congenital or acquired anomalies of the pulmonary veins between June 1999 and December 2001. The patient's ages varied from 1 month to 10 years. The examinations were carried out on a 1.5 T Vision machine (Siemens, Erlangen, Germany) without "cardiac gating" or apnoea after parental consent. MRA with gadolinium injection showed 5 drainage anomalies (3 partial pulmonary venous refluxes in the superior vena cava, 2 scimitar syndromes) and 3 stenoses (one due to compression by an aneurysm of the left pulmonary artery, a second secondary to pericardial agenesis, and a third secondary to hypoplasia of an isolated vein). MRA allowed three dimensional visualisation of these anomalies. This is a rapid, non-invasive and certain imaging technique which does not expose the patient to ionising radiation. It is therefore of significance in the investigation of anomalies of the pulmonary veins complementing echocardiography, and could in future replace cardiac catheterisation.

Preoperative fenestration for type A acute aortic dissection with mesenteric malperfusion

We report a case of a 71-year-old man presenting with acute type A aortic dissection and mesenteric ischemia due to extension of the intimal flap to the mesenteric artery. Because of the severity of the abdominal symptoms, surgical correction of the ascending aorta was delayed. Preoperative percutaneous fenestration was performed successfully, allowing ascending aortic replacement 6 days later. Transverse colon stenosis secondary to preoperative ischemia occurred in the postoperative course. The patient was discharged from hospital with normal intestinal transit 72 days later.

Rupture of an aneurysm of the coronary sinus of Valsalva: diagnosis by helical CT angiography

A 75-year-old man presented with a 5-day history of upper chest discomfort. On auscultation, there was a systolic murmur in the left parasternal area that radiated to the apex. Electrocardiography showed flat T waves in the anterior precordial leads. Chest X ray revealed mediastinal enlargement. Transthoracic echocardiography showed a dilated proximal ascending aorta with moderate aortic regurgitation. A contrast-enhanced helical CT scan, performed to eliminate an aortic dissection, showed a ruptured left coronary sinus of Valsalva aneurysm, confirmed at surgery. This case highlights the fact that helical CT, in patients with suspected aortic dissection, may reveal other pathology that accounts for the clinical presentation.

Embolization of type II endoleaks after aortic stent-graft implantation: technique and immediate results

PURPOSE

We report the procedural details and immediate results of treatment of type II endoleaks after aortic stent-graft implantation.

METHODS

In a consecutive series of patients who had either Vangard (n = 53) or Talent (n = 7) aortic stent-grafts implanted, type II endoleaks were confirmed by means of angiography in 18 patients, with a mean (+/- SD) age of 69 +/- 11 years; 16 patients had Vangard stent-grafts, and two patients had Talent stent-grafts. After superselective catheterization of the feeding vessel, with 3F microcatheters, and liberal injections of vasodilators, embolization was performed with either a mixture of biologic glue and Lipiodol (n = 16) or Microcoils (n = 2).

RESULTS

The procedure was performed through the femoral artery in 16 patients and through the brachial artery in the remaining two patients. Overall, superselective catheterization and embolization were successfully undertaken in 17 (94.4%) of 18 patients. In the remaining patient, superselective catheterization proved impossible. This patient was treated with an injection of microparticles completed by means of embolization of biologic glue more proximally in an iliolumbar branch. During follow-up (mean, 13.3 months) after embolization, the aneurysm sac shrank in 13 (72.2%) of 18 patients. A new type II endoleak was diagnosed on helical computed tomography or magnetic resonance imaging in two (11.1%) of 18 patients.

CONCLUSION

Percutaneous embolization is a safe and effective technique for treatment of type II endoleaks. However, despite these initially promising results, large long-term follow-up studies will be required to confirm its efficiency.