Publications by authors named "Christoph A Binkert"

79 Publications

Contrast-Enhanced T1-Weighted Head and Neck MRI: Prospective Intraindividual Image Quality Comparison of Spiral GRE, Cartesian GRE, and Cartesian TSE Sequences.

AJR Am J Roentgenol 2021 Aug 18. Epub 2021 Aug 18.

Institute of Radiology, Kantonsspital Winterthur, Brauerstrasse 15, 8401 Winterthur, Switzerland.

Sequences with non-Cartesian k-space sampling may improve image quality of head and neck MRI. To compare intraindividually the image quality of a spiral gradient recalled echo (GRE) sequence and conventional Cartesian GRE and Cartesian turbo spin echo (TSE) sequences for contrast-enhanced T1W head and neck MRI. This prospective study included patients referred for contrast-enhanced head and neck MRI from August 2020 to May 2021. Patients underwent 1.5-T MRI including contrast-enhanced spiral GRE (2:28 min), Cartesian GRE (4:27 min), and Cartesian TSE (3:41 min) sequences, acquired in rotating order across patients. Three radiologists independently assessed image quality measures using 5-point Likert scales, including conspicuity of prespecified lesions. One reader measured maximal extent of dental material artifact and contrast-to-noise ratio (CNR). Thirty-one patients (13 male, 18 female; mean age 63.8 years) were enrolled. Nineteen patients had a focal lesion; 22 had dental material. Interreader agreement for image quality measures was substantial to excellent (Krippendorff's alpha, 0.681-1.000). Scores were better for spiral GRE than Cartesian GRE and Cartesian TSE for all readers (p<.05) for overall image quality (whole head and neck; neck only; head only), pulsation artifact, muscular contour delineation, vessel contour delineation, motion artifact, and differentiation between mucosa and pharyngeal muscles. Scores were not different between spiral GRE and the other sequences for any reader (p>.05) for lesion conspicuity (whole head and neck; neck only; head only), fat suppression, flow artifact, and foldover-type artifact. Scores were worse for spiral GRE than the other sequences for all readers (p<.05) for dental material artifact. Maximum extent of dental material artifact was 39.6±25.5 mm for spiral GRE, 35.6±24.3 mm for Cartesian GRE, and 29.6±21.4 mm for Cartesian GRE; CNR was 221.1±94.5 for spiral GRE, 151.8±85.7 for Cartesian GRE, and 153±63.2 for Cartesian TSE (p<.001 between spiral GRE and other sequences for both measures). 3D spiral GRE improves subjective image quality and CNR of head and neck MRI with shorter scan time versus Cartesian sequences, though exhibits larger dental material artifact. A spiral sequence may help overcome certain challenges of conventional Cartesian sequences for head and neck MRI.
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http://dx.doi.org/10.2214/AJR.21.26413DOI Listing
August 2021

Introduction and reproducibility of an updated practical grading system for lumbar foraminal stenosis based on high-resolution MR imaging.

Sci Rep 2021 Jun 7;11(1):12000. Epub 2021 Jun 7.

Institute of Radiology, Kantonsspital Winterthur, Brauerstrasse 15, 8401, Winterthur, Switzerland.

In this paper we sought to develop and assess the reproducibility of an updated 6-point grading system for lumbar foraminal stenosis based on the widely used Lee classification that more accurately describes lumbar foraminal stenosis as seen on high-resolution MRI. Grade A indicates absence of foraminal stenosis. Grades B, C, D and E indicate presence of foraminal stenosis with contact of the nerve root with surrounding anatomical structures (on one, two, three or four sides for B, C, D and E respectively) yet without morphological change of the nerve root. To each grade, a number code indicating the location of contact between the nerve root and surrounding anatomical structure(s) is appended. 1, 2, 3 and 4 indicate contact of the nerve root at superior, posterior, inferior and anterior position of the borders of the lumbar foramen. Grade F indicates presence of foraminal stenosis with morphological change of the nerve root. Three readers graded the lumbar foramina of 101 consecutive patients using high-resolution T2w (and T1w) MR images with a spatial resolution of beyond 0.5 mm. Interreader agreement was excellent (Cohen's Kappa = 0.866-1). Importantly, 30.6%/31.6%/32.2% (reader 1/reader 2/ reader 3) of foramina were assigned grades that did not appear in the original Lee grading system (grades B and D). The readers found no foramen that could not be described accurately with the updated grading system. Thus, an updated 6-point grading system for lumbar foraminal stenosis is reproducible and comprehensively describes lumbar foraminal stenosis as seen on high-resolution MRI.
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http://dx.doi.org/10.1038/s41598-021-91462-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8184791PMC
June 2021

Combined simultaneous embolization of the portal vein and hepatic vein (double vein embolization) - a technical note about embolization sequence.

CVIR Endovasc 2021 May 26;4(1):43. Epub 2021 May 26.

Department of Radiology and Nuclear Medicine, Kantonsspital Winterthur, Brauerstrasse 15, 8401, Winterthur, Switzerland.

Background: Simultaneous portal vein embolization (PVE) and hepatic vein embolization (HVE) has been shown to be feasible, safe and lead to a faster growth of future liver remnant (FLR) than PVE alone. The objective of this study is to highlight different technical aspects as well as importance of embolization order.

Materials And Methods: Seven patients were treated with simultaneous PVE and HVE. In three cases, HVE was performed first followed by PVE and in four cases the other way around. Portal vein branches were embolized using Glubran-Lipiodol mixture in all cases. Hepatic veins were embolized using Amplatzer II plugs sized 8-20 mm. Specific consideration was given to depth of glue penetration in the portal vein defined by visible branch order on the treated side.

Results: Six of seven patients were discharged home the same day. One patient with infected tumor necrosis died of liver failure 40 days later, otherwise there were no periprocedural clinical complications. Median glue penetration was to the 5th order (4th - 5th) when PVE was performed first and 3rd order (2nd - 4th) when PVE was performed after HVE. In one PVE first case, glue spillage was seen due to marked reduced flow in the right portal vein. There was sufficient FLR growth for subsequent surgical resection in the remaining six patients.

Conclusion: PVE should be performed prior to HVE because the reduced flow in the portal vein after HVE leads to less deep glue penetration with presumably increased risk of contralateral spillage.
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http://dx.doi.org/10.1186/s42155-021-00230-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8155155PMC
May 2021

Correction to: BIOLUX P-III Passeo-18 Lux All-Comers Registry: 24-Month Results in Below-the-Knee Arteries.

Cardiovasc Intervent Radiol 2021 Aug;44(8):1307

Division of Angiology, Department of Internal Medicine, Medical University Graz, Graz, Austria.

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http://dx.doi.org/10.1007/s00270-021-02861-xDOI Listing
August 2021

Amide proton transfer weighted (APTw) imaging based radiomics allows for the differentiation of gliomas from metastases.

Sci Rep 2021 Mar 9;11(1):5506. Epub 2021 Mar 9.

Department of Neuroradiology, Kantonsspital Aarau, Aarau, Switzerland.

We sought to evaluate the utility of radiomics for Amide Proton Transfer weighted (APTw) imaging by assessing its value in differentiating brain metastases from high- and low grade glial brain tumors. We retrospectively identified 48 treatment-naïve patients (10 WHO grade 2, 1 WHO grade 3, 10 WHO grade 4 primary glial brain tumors and 27 metastases) with either primary glial brain tumors or metastases who had undergone APTw MR imaging. After image analysis with radiomics feature extraction and post-processing, machine learning algorithms (multilayer perceptron machine learning algorithm; random forest classifier) with stratified tenfold cross validation were trained on features and were used to differentiate the brain neoplasms. The multilayer perceptron achieved an AUC of 0.836 (receiver operating characteristic curve) in differentiating primary glial brain tumors from metastases. The random forest classifier achieved an AUC of 0.868 in differentiating WHO grade 4 from WHO grade 2/3 primary glial brain tumors. For the differentiation of WHO grade 4 tumors from grade 2/3 tumors and metastases an average AUC of 0.797 was achieved. Our results indicate that the use of radiomics for APTw imaging is feasible and the differentiation of primary glial brain tumors from metastases is achievable with a high degree of accuracy.
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http://dx.doi.org/10.1038/s41598-021-85168-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7943598PMC
March 2021

Ambulatory Care in IR: Time to Engage.

Cardiovasc Intervent Radiol 2021 Jul 21;44(7):1003-1004. Epub 2021 Mar 21.

Radiology and Nuclear Medicine, Kantonsspital Winterthur, Brauerstrasse 15, CH-8401, Winterthur, Switzerland.

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http://dx.doi.org/10.1007/s00270-021-02825-1DOI Listing
July 2021

Qualitative and Quantitative Analysis of a Spiral Gradient Echo Sequence for Contrast-Enhanced Fat-Suppressed T1-Weighted Spine Magnetic Resonance Imaging.

Invest Radiol 2021 Aug;56(8):517-524

From the Institute of Radiology, Kantonsspital Winterthur, Brauerstrasse 15, 8401 Winterthur, Switzerland.

Objectives: Pulse sequences with non-Cartesian k-space sampling enable improved imaging in anatomical areas with high degrees of motion artifacts. We analyzed a novel spiral 3-dimensional (3D) gradient echo (GRE) magnetic resonance imaging (MRI) sequence ("spiral," 114.7 ± 11 seconds) and compared it with a radial 3D GRE ("vane," 216.7 ± 2 seconds) and a conventional Cartesian 2D turbo spin echo (TSE) sequence ("TSE," 266.7 ± 82 seconds) for contrast-enhanced fat-suppressed T1-weighted spine imaging.

Materials And Methods: Forty consecutive patients referred for contrast-enhanced MRI were prospectively scanned with all 3 sequences. A qualitative analysis was performed by 3 readers using 4- or 5-point Likert scales to independently grade images in terms of overall image quality, occurrence of artifacts, lesion conspicuity, and conspicuity of nerve roots. The numbers of visible nerve roots per sequence and patient were counted in consensus. Coefficient of variation measurements were performed for the paravertebral musculature (CVPM) and the spinal cord (CVSC).

Results: Spiral (median [interquartile range], 5 [4-5]) exhibited improved overall image quality in comparison to TSE (3 [3-4]) and vane (4 [4-5]; both P < 0.001). Vane surpassed TSE in terms of overall image quality (P < 0.001). Spiral (4 [3.75-4]) and vane (3.5 [3-4]) presented with less artifacts than TSE (3 [2.75-3.25]; both P < 0.001). Spiral (4 [4-5]) outperformed vane (4 [3-5]; P = 0.01) and TSE (4 [3-4]; P = 0.04) in terms of lesion conspicuity. Conspicuity of nerve roots was superior on spiral (3 [3-4]) and vane (4 [3-4]) when compared with TSE (1.5 [1-2]; both P < 0.001). Readers discerned significantly more nerve roots on spiral (4 [2.75-8]) and vane (4 [3.75-7.25]) images when compared with TSE (2 [0-4]; both P < 0.001). Interreader agreement ranged from moderate (α = 0.639) to almost perfect (α = 0.967). CVPM and CVSC were significantly lower on spiral as compared with vane and TSE (P < 0.001, P = 0.04). Vane exhibited lower CVPM and CVSC than TSE (P < 0.001, P = 0.01).

Conclusions: A novel spiral 3D GRE sequence improves contrast-enhanced fat-suppressed T1-weighted spinal imaging qualitatively and quantitatively in comparison with a conventional Cartesian 2D TSE sequence and to a lesser extent with a radial 3D GRE sequence at shorter scan times.
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http://dx.doi.org/10.1097/RLI.0000000000000770DOI Listing
August 2021

Impact of Acoustic Noise Reduction on Patient Experience in Routine Clinical Magnetic Resonance Imaging.

Acad Radiol 2020 Nov 3. Epub 2020 Nov 3.

Department of Radiology, Kantonsspital Winterthur, Brauerstrasse 15, 8405, Winterthur, Switzerland. Electronic address:

Objectives: Acoustic noise emission from MRI scanners is considered a major factor of patient discomfort during routine MRI examinations. We prospectively evaluated the impact of acoustic noise reduction using software implementations in routine clinical MRI on subjective patient experience and image quality.

Methods: Two-hundred consecutive patients undergoing one of four MRI examinations (brain, lumbar spine, shoulder, and knee) at a single center were prospectively randomized into two groups at a 1 to 1 ratio: standard MRI examination and MRI examination with acoustic noise reduction. After the examination, patients were asked to complete a questionnaire aimed at defining their subjective experience (primary endpoint). Two readers assessed subjective image quality of all patient studies in consensus (secondary endpoint). Nonparametric tests and logistic regression models were used for statistical analysis.

Results: Hundred-seventy-four patients were included in the final study. Patients in the intervention group felt less discomforted by the acoustic noise (p = 0.01) and reported increased audibility of music through the headphones (p = 0.03). No significant difference in subjective image quality was found.

Conclusion: Our study indicates that the effects of acoustic noise reduction in routine clinical MRI can be translated into reduced patient discomfort from acoustic noise and improved audibility of music. Acoustic noise reduction thus significantly contributes to increased patient comfort during MRI examinations.
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http://dx.doi.org/10.1016/j.acra.2020.10.012DOI Listing
November 2020

Paclitaxel-Coated Balloon Angioplasty for the Treatment of Infrainguinal Arteries: 24-Month Outcomes in the Full Cohort of BIOLUX P-III Global Registry.

Cardiovasc Intervent Radiol 2021 Feb 20;44(2):207-217. Epub 2020 Oct 20.

Division of Angiology, Department of Internal Medicine, Medical University Graz, Graz, Austria.

Purpose: After promising small randomized trials, the aim of BIOLUX P-III was to further investigate the safety and performance of the Passeo-18 lx drug-coated balloon in infrainguinal arteries under real-world conditions.

Methods: BIOLUX P-III is a global prospective single-arm study with follow-up at 6, 12 and 24 months. The primary safety endpoint was freedom from major adverse events (MAE) within 6 months. The primary performance endpoint was freedom from clinically driven target lesion revascularization (TLR) within 12 months.

Results: 877 patients/1084 lesions were enrolled. Diabetes mellitus was present in 47.7%, and 42.1% had critical limb ischemia (CLI). The mean lesion length was 89.0 mm with 76.1% of calcified lesions, and 24.9% occluded. At 24 months, freedom from MAE was 83.1% in the full cohort; 84.9% in the femoropopliteal population (592 patients, 691 lesions); 77.7% for long lesions (187 subjects/192 lesions); and 72.5% in the in-stent restenosis (ISR) subgroup (103 subjects/116 lesions). Twenty-four-month freedom from clinically driven TLR was 88.1% in the full cohort; 88.9% in the femoropopliteal population; 80.3% for the long lesions; and 78.4% for ISR. Twenty-four-month all-cause mortality was 12.0% in the full cohort, 10.2% in the femoropopliteal population, 14.8% for the long lesions and 12.0% for ISR. There was no device- or procedure-related death up to 24-month follow-up.

Conclusion: The BIOLUX P-III 24-month outcomes confirm the safety and performance of Passeo-18 lx in infrainguinal arteries in a large population treated under real-world conditions with low complication rates and good clinical outcomes (NCT02276313).
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http://dx.doi.org/10.1007/s00270-020-02663-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7806550PMC
February 2021

BIOLUX P-III Passeo-18 Lux All-Comers Registry: 24-Month Results in Below-the-Knee Arteries.

Cardiovasc Intervent Radiol 2021 Jan 22;44(1):10-18. Epub 2020 Sep 22.

Division of Angiology, Department of Internal Medicine, Medical University Graz, Graz, Austria.

Purpose: The BIOLUX P-III registry was initiated to further assess the safety and efficacy of the Passeo-18 Lux drug-coated balloon (DCB) in infrainguinal lesions in a real-world environment and in prespecified risk groups.

Materials And Methods: BIOLUX P-III is a prospective, global, all-comers registry with patients treated under real-world conditions. We herein report 24-month results of the prespecified subgroup of 151 patients with 185 below-the-knee (BTK) lesions. The primary safety and efficacy endpoints were freedom from major adverse events (a composite of freedom from device and procedure mortality through 30 days, major target limb amputation and clinically driven target lesion revascularization) at 6 months and freedom from clinically driven target lesion revascularization (FfTLR) at 12 months.

Results: At baseline, 76.0% of patients had critical limb ischemia and 48.9% of lesions were TASC C or D lesions. Technical success was achieved in 97.8%, and bailout stenting was required in 1.1%. Freedom from major adverse events was 86.2% [95% CI 79.4; 90.8] at 6 months, and FfTLR was 90.9% [95% CI 85.2; 94.4] at 12 months. At 24 months, FfTLR was 90.9% [95% CI 85.2; 94.4], freedom from major amputation was 90.1% [95% CI 83.9, 94.0], and overall survival was 79.2% [70.7, 85.5]. There was a significant clinical improvement (mean Rutherford class improvement of - 2.9 ± 1.9, p < 0.0001) and an improvement in pain (mean improvement on Wong-Baker Faces Pain Scale of - 2.7 ± 2.9, p < 0.0001).

Conclusions: In this real-world DCB registry, 24-month outcomes of Passeo-18 Lux demonstrated safety and efficacy in BTK lesions with high patency rates and sustained clinical improvements at 24 months.

Trial Registration: NCT02276313.
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http://dx.doi.org/10.1007/s00270-020-02586-3DOI Listing
January 2021

Spiral 3-Dimensional T1-Weighted Turbo Field Echo: Increased Speed for Magnetization-Prepared Gradient Echo Brain Magnetic Resonance Imaging.

Invest Radiol 2020 12;55(12):775-784

From the Institute of Radiology, Kantonsspital Winterthur, Winterthur.

Objectives: Spiral magnetic resonance imaging acquisition may enable improved image quality and higher scan speeds than Cartesian trajectories. We tested the performance of four 3D T1-weighted (T1w) TFE sequences (magnetization-prepared gradient echo magnetic resonance sequence) with isotropic spatial resolution for brain imaging at 1.5 T in a clinical patient cohort based on qualitative and quantitative image quality metrics. Two prototypical spiral TFE sequences (spiral 1.0 and spiral 0.85) and a Cartesian compressed sensing technology accelerated TFE sequence (CS 2.5; acceleration factor of 2.5) were compared with a conventional (reference standard) Cartesian parallel imaging accelerated TFE sequence (SENSE; acceleration factor of 1.8).

Materials And Methods: The SENSE (5:52 minutes), CS 2.5 (3:17 minutes), and spiral 1.0 (2:16 minutes) sequences all had identical spatial resolutions (1.0 mm). The spiral 0.85 (3:47 minutes) had a higher spatial resolution (0.85 mm). The 4 TFE sequences were acquired in 41 patients (20 with and 21 without contrast media). Three readers rated qualitative image quality (12 categories) and selected their preferred sequence for each patient. Two readers performed quantitative analysis whereby 6 metrics were derived: contrast-to-noise ratio for white and gray matter (CNRWM/GM), contrast ratio for gray matter-CSF (CRGM/CSF), and white matter-CSF (CRWM/CSF); and coefficient of variations for gray matter (CVGM), white matter (CVWM), and CSF (CVCSF). Friedman tests with post hoc Nemenyi tests, exact binomial tests, analysis of variance with post hoc Dunnett tests, and Krippendorff alphas were computed.

Results: Concerning qualitative analysis, the CS 2.5 sequence significantly outperformed the SENSE in 4/1 (with/without contrast) categories, whereas the spiral 1.0 and spiral 0.85 showed significantly improved scores in 10/9and 7/7 categories, respectively (P's < 0.001-0.039). The spiral 1.0 was most frequently selected as the preferred sequence (reader 1, 10/15 times; reader 2, 9/12 times; reader 3, 11/13times [with/without contrast]). Interreader agreement ranged from substantial to almost perfect (alpha = 0.615-0.997). Concerning quantitative analysis, compared with the SENSE, the CS 2.5 had significantly better scores in 2 categories (CVWM, CVCSF) and worse scores in 2 categories (CRGM/CSF, CRWM/CSF), the spiral 1.0 had significantly improved scores in 4 categories (CNRWM/GM, CRGM/CSF, CRWM/CSF, CVWM), and the spiral 0.85 had significantly better scores in 2 categories (CRGM/CSF, CRWM/CSF).

Conclusions: Spiral T1w TFE sequences may deliver high-quality clinical brain imaging, thus matching the performance of conventional parallel imaging accelerated T1w TFEs. Imaging can be performed at scan times as short as 2:16 minutes per sequence (61.4% scan time reduction compared with SENSE). Optionally, spiral imaging enables increased spatial resolution while maintaining the scan time of a Cartesian-based acquisition schema.
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http://dx.doi.org/10.1097/RLI.0000000000000705DOI Listing
December 2020

Clinical feasibility of ultrafast intracranial vessel imaging with non-Cartesian spiral 3D time-of-flight MR angiography at 1.5T: An intra-individual comparison study.

PLoS One 2020 29;15(4):e0232372. Epub 2020 Apr 29.

Institute of Radiology, Winterthur Cantonal Hospital, Winterthur, Switzerland.

Objectives: Non-Cartesian Spiral readout can be implemented in 3D Time-of-flight (TOF) MR angiography (MRA) with short acquisition times. In this intra-individual comparison study we evaluated the clinical feasibility of Spiral TOF MRA in comparison with compressed sensing accelerated TOF MRA at 1.5T for intracranial vessel imaging as it has yet to be determined.

Materials And Methods: Forty-four consecutive patients with suspected intracranial vascular disease were imaged with two Spiral 3D TOFs (Spiral, 0.82x0.82x1.2 mm3, 01:32 min; Spiral 0.8, 0.8x0.8x0.8 mm3, 02:12 min) and a Compressed SENSE accelerated 3D TOF (CS 3.5, 0.82x0.82x1.2 mm3, 03:06 min) at 1.5T. Two neuroradiologists assessed qualitative (visualization of central and peripheral vessels) and quantitative image quality (Contrast Ratio, CR) and performed lesion and variation assessment for all three TOFs in each patient. After the rating process, the readers were questioned and representative cases were reinspected in a non-blinded fashion. For statistical analysis, the Friedman and Nemenyi post-hoc test, Kendall W tests, repeated measure ANOVA and weighted Cohen's Kappa tests were used.

Results: The Spiral and Spiral 0.8 outperformed the CS 3.5 in terms of peripheral image quality (p<0.001) and performed equally well in terms of central image quality (p>0.05). The readers noted slight differences in the appearance of maximum intensity projection images. A good to high degree of interstudy agreement between the three TOFs was observed for lesion and variation assessment (W = 0.638, p<0.001 -W = 1, p<0.001). CR values did not differ significantly between the three TOFs (p = 0.534). Interreader agreement ranged from good (K = 0.638) to excellent (K = 1).

Conclusions: Compared to the CS 3.5, both the Spiral and Spiral 0.8 exhibited comparable or better image quality and comparable diagnostic performance at much shorter acquisition times.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0232372PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7190165PMC
July 2020

Alternative crossing technique for iliaco-femoro-popliteal CTOs with a catheter only.

CVIR Endovasc 2019 Jul 18;2(1):23. Epub 2019 Jul 18.

Department of Radiology and Nuclear medicine, Canton Hospital Winterthur, 8401, Winterthur, Switzerland.

Background: The standard approach for crossing peripheral CTOs is to use a combination of hydrophilic guidewires and catheters. The path is either intraluminally or in most cases at least partially subintimal. This standard approach with a guidewire-tip as leading point ("wire first") to cross CTOs has a success rate of about 80%. We hypothesize that a "catheter first" approach, using the catheter alone for the entire recanalization till re-entering the vessel is less traumatic and might lead to a longer intraluminal recanalization due to a softer leading point. Based on this assumption we analyzed the success and duration of this approach with a gradual step-up approach from catheter tip to guidewire front-end to guidewire back-end. To the best of our knowledge, no studies measuring the time of recanalization of lower extremity CTOs using conventional devices were published yet.

Results: Data of 46 consecutive chronic total iliaco-femoro-popliteal occlusions in 43 symptomatic patients treated by percutaneous transluminal angioplasty were collected prospectively between May 1st 2014 and June 30th 2016 and evaluated retrospectively. Chronic occlusion was defined as clinical symptoms or imaging features lasting more than 1 month. Patient age and gender, diabetes status, localization of occlusion, occlusion length, duration of symptoms, severity of vessel calcification, and recanalization time were assessed. Technical success was defined as placement of a catheter beyond the distal end of the lesion into the true lumen, confirmed by contrast injection. All 46 CTOs were successfully recanalized. In 22 cases (47.8%) recanalization was successful with the catheter tip only without the use of a guide wire. In 17 cases (36.9%) the guide wire was used in addition to the catheter. Localization of occlusion did not have an effect on the recanalization technique (p = 0.915). The mean rank for length of occlusion was not significant for different recanalization techniques (p = 0.095). The success rate for the catheter only approach was lower for higher grades of calcification (p = 0.008). There was no correlation between time of recanalization and length of occlusion (Pearson's r = 0.004; adjusted R square = - 0.024; p = 0.980), diabetes (p = 1.000), sex (p = 0.244), or grade of calcification (p = 0.621). Recanalization time is significantly right-skewed with most recanalizations being successful under 30 min.

Conclusion: This "catheter first" approach is somewhat contradictory to the prevailing dogma of "wire first". The concept to use the catheter to start a recanalization is well known, but to perform the entire recanalization including the re-entry seems possible and potentially less traumatic, likely leading to a longer intraluminal course. Our data shows that recanalization of occluded lower extremity arteries between the aortic bifurcation and the popliteal artery can be achieved in the majority of cases (84.7%) solely by using an angled angiographic catheter +/- glide wire. We suggest a "5 min - 15 min - 30 min" rule on how long to attempt each recanalization technique. More precisely, we suggest trying 5 min with the catheter alone, then 10 min with the soft end of the guidewire and then switching to the stiffer back-end of the guidewire for another 15 min.
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http://dx.doi.org/10.1186/s42155-019-0065-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6966370PMC
July 2019

Outcome of Nellix-EVAS: single center mid-term results.

CVIR Endovasc 2019 Apr 23;2(1):13. Epub 2019 Apr 23.

Department of Radiology and Nuclear Medicine, Canton Hospital Winterthur, 8401, Winterthur, Switzerland.

Background: Endovascular aortic sealing (EVAS) using the Nellix system was a new approach to reduce the frequency of type II endoleaks after endovascular aortic repair. We analyzed the mid-term results, specifically looking at device migration, endoleaks and subsequent necessary secondary interventions.

Results: Ten patients underwent elective EVAS treatment during our study period. 7 patients were within the IFU while 3 patients had a proximal neck shorter than 10 mm. Technical success rate was 100% and there were no short-term vascular complications. One patient died from urosepsis 14 days after the procedure and was excluded from further analysis. A total of 6 out of 9 patients (67%) experienced device complications such as proximal graft kinking, limb separation or caudal migration. 5 also showed type Ia endoleak.

Discussion: While no complication occurred short-term (up to 12 months), the Nellix system showed a high percentage of limb separation, caudal graft migration, and type Ia endoleak on mid-term follow-up, likely due to insufficient proximal anchoring of the device. Possible salvage treatments are discussed.
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http://dx.doi.org/10.1186/s42155-019-0058-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7224240PMC
April 2019

Paclitaxel-Coated Balloon for the Treatment of Infrainguinal Disease: 12-Month Outcomes in the All-Comers Cohort of BIOLUX P-III Global Registry.

J Endovasc Ther 2020 04 28;27(2):304-315. Epub 2020 Jan 28.

Division of Angiology, Department of Internal Medicine, Medical University Graz, Austria.

To further investigate the safety and performance of the Passeo-18 Lux drug-coated balloon (DCB) for the treatment of atherosclerotic infrainguinal disease under real-world conditions. BIOLUX P-III is an international, prospective, observational registry ( identifier NCT02276313) conducted at 41 centers in Europe, Asia, and Australia with follow-up visits at 6, 12, and 24 months. Of 700 patients (mean age 70.0±10.2 years; 439 men) with 863 lesions in the all-comers cohort, 330 (47.1%) patients had diabetes and 234 (37.7%) had chronic limb-threatening ischemia. The majority (79.3%) of lesions were in the femoropopliteal segment; of all lesions, 645 (74.9%) were calcified and 99 (11.5%) had in-stent restenosis (ISR). The mean lesion length was 84.7±73.3 mm. The primary clinical endpoint was major adverse events (MAEs) within 6 months, a composite of device- and procedure-related mortality through 30 days, major target limb amputation, and clinically-driven target lesion revascularization (TLR). The primary performance endpoint was clinically-driven TLR within 12 months. At 6 and 12 months, freedom from MAEs was 94.0% and 89.5% in the all-comers cohort: 95.0% and 91.2% in the femoropopliteal group and 95.3% and 88.0% in the ISR subgroup, respectively. Freedom from clinically-driven TLR at 12 months was 93.1% in the all-comers cohort, 93.9% in the femoropopliteal lesions, and 89.4% for ISR lesions. All-cause mortality was 6.1% in the all-comers cohort: 5.9% in both the femoropopliteal and ISR subgroups. There were no device- or procedure-related deaths at up to 12 months. The Rutherford category improved in >80% of all subgroups at 12 months. In a real-world patient population, the safety and performance of the Passeo-18 Lux DCB for the treatment of atherosclerotic infrainguinal lesions are maintained, with good performance outcomes and low complication rates at 12 months.
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http://dx.doi.org/10.1177/1526602819898804DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7082893PMC
April 2020

Ultrafast Intracranial Vessel Imaging With Non-Cartesian Spiral 3-Dimensional Time-of-Flight Magnetic Resonance Angiography at 1.5 T: An In Vitro and Clinical Study in Healthy Volunteers.

Invest Radiol 2020 05;55(5):293-303

From the Institute of Radiology, Kantonsspital Winterthur, Winterthur.

Objectives: Non-Cartesian spiral magnetic resonance (MR) acquisition may enable higher scan speeds, as the spiral traverses the k-space more efficiently per given time than in Cartesian trajectories. Spiral MR imaging can be implemented in time-of-flight (TOF) MR angiography (MRA) sequences. In this study, we tested the performance of five 3-dimensional TOF MRA sequences for intracranial vessel imaging at 1.5 T with qualitative and quantitative image quality metrics based on in vitro and in vivo measurements. Specifically, 3 novel spiral TOF MRA sequences (spiral-TOFs) and a compressed sensing (CS) technology-accelerated TOF MRA sequence (CS 3.5) were compared with a conventional (criterion standard) parallel imaging-accelerated TOF MRA sequence (SENSE).

Materials And Methods: The SENSE sequence (5:08 minutes) was compared with the CS 3.5 sequence (3:06 minutes) and a spiral-TOF (spiral, 1:32 minutes), all with identical resolutions. In addition, 2 further isotropic spiral-TOFs (spiral 0.8, 2:12 minutes; spiral 0.6, 5:22 minutes) with higher resolution were compared with the SENSE. First, vessel tracking experiments were performed in vitro with a dedicated vascular phantom to determine possible differences in the depiction of cross-sectional areas of vessel segments. For the in vitro tests, an additional 3-dimensional proton density-weighted sequence was added for comparison reasons. Second, 3 readers blinded to sequence details assessed qualitative (16 features) and 2 readers assessed quantitative (contrast-to-noise ratio [CNR], contrast ratio [CR], vessel sharpness, and full width at half maximum edge criterion measurements) image quality based on images acquired from scanning 10 healthy volunteers with all 5 TOF sequences. Scores from quantitative image quality analysis were compared with Kruskal-Wallis, analysis of variance, or Welch's analysis of variance, followed by Dunnett's or Dunnett's T3 post hoc tests. Scores from qualitative image quality analysis were compared with exact binomial tests, and the level of interreader agreement was determined with Krippendorff's alpha.

Results: Concerning the in vitro tests, there were no significant differences between the 5 TOFs and the proton density-weighted sequence in measuring cross-sectional areas of vessel segments (P = 0.904). As for the in vivo tests, the CS 3.5 exhibited equal qualitative image quality as the SENSE, whereas the 3 spiral-TOFs outperformed the SENSE in several categories (P values from 0.002 to 0.031). Specifically, the spiral 0.8 and 0.6 sequences achieved significantly higher scores in 12 categories. Interreader agreement ranged from poor (alpha = -0.013, visualization of internal carotid artery segment C7) to substantial (alpha = 0.737, number of vessels visible, sagittal). As for the quantitative metrics, the CS 3.5 and all 3 spiral-TOFs presented with significantly worse CNR than the SENSE ([mean ± SD] SENSE 37.48 ± 7.13 vs CS 3.5 31.14 ± 5.97 vs spiral 19.77 ± 1.65 vs spiral 0.8 16.18 ± 2.14 vs spiral 0.6 10.37 ± 1.05). The CR values did not differ significantly between the SENSE and the other TOFs except for the spiral sequence that showed significantly improved CR (SENSE 0.53 ± 0.03 vs spiral 0.56 ± 0.03). As for vessel sharpness, the SENSE was outperformed by all spiral-TOFs (SENSE 0.37 ± 0.03 vs spiral 0.52 ± 0.07 vs spiral 0.8 0.53 ± 0.08 vs spiral 0.6 0.73 ± 0.09), whereas the CS 3.5 performed equally well (SENSE 0.37 ± 0.03 vs CS 3.5 0.37 ± 0.03). Full width at half maximum values did not differ significantly between any TOF.

Conclusions: Spiral-TOFs may deliver high-quality intracranial vessel imaging thus matching the performance of conventional parallel imaging-accelerated TOFs (such as the SENSE). Specifically, imaging can be performed at unprecedented scan times as short as 1:32 minutes per sequence (70.12% scan time reduction compared with SENSE). Optionally, spiral imaging may also be used to increase spatial resolution while maintaining the scan time of a Cartesian-based acquisition schema. The CNR was decreased in spiral-TOF images.
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http://dx.doi.org/10.1097/RLI.0000000000000641DOI Listing
May 2020

Angiographic Detection of Utero-Ovarian Anastomosis and Influence on Ovarian Function After Uterine Artery Embolization.

Cardiovasc Intervent Radiol 2020 Feb 17;43(2):231-237. Epub 2019 Sep 17.

Department of Radiology and Nuclear Medicine, Cantonal Hospital Winterthur, Brauerstr. 15, 8401, Winterthur, Switzerland.

Purpose: To assess the detectability and frequency of the different types of utero-ovarian anastomosis, the correlation between type of anastomosis and ovarian failure after UAE, as well as the impact of coiling as a strategy for the prevention of ovarian failure.

Materials And Methods: We retrospectively studied a population of 92 women treated with uterine artery embolization at our institution between 2007 and 2017. Utero-ovarian anastomoses were categorized on angiographic sequences by two radiologists based on the classification published by Razavi et al. (Radiology 224(3):707-712, 2002), and Cohen's kappa was calculated. Ovarian failure was defined as an increase in serum FSH above 27 mIU/ml three months after embolization.

Results: Out of a total of 184 anastomoses, 27% were classified as type Ia, 45% as type Ib, 1% as type II and 24% as type III. Three percent of anastomoses could not be determined. There was very good inter-observer reliability on the classification of utero-ovarian anastomoses (κ = 0.847). Ovarian failure occurred in six out of 92 women (7%). Each had at least one type Ib (n = 4) or type III (n = 1) anastomosis, with the exception of one patient in whom the type of anastomosis could not be determined. All women presenting with ovarian failure were 45 years of age or older. No patient with protective coiling developed ovarian failure.

Conclusion: Utero-ovarian anastomoses are more common than previously expected and can be reliably classified with very good inter-observer reliability. Patients with type Ib and type III anastomoses carry the risk of ovarian failure after uterine artery embolization. Protective coiling seems to be an adequate strategy for avoiding ovarian failure in those types of anastomoses.
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http://dx.doi.org/10.1007/s00270-019-02305-7DOI Listing
February 2020

Sacroiliac Joint Ablation Using MR-HIFU.

Cardiovasc Intervent Radiol 2019 Sep 11;42(9):1363-1365. Epub 2019 Jun 11.

Department of Radiology and Nuclear Medicine, Canton Hospital Winterthur, 8401, Winterthur, Switzerland.

The sacroiliac joint is the culprit in 15-30% of patients with chronic lumbar back pain. Ablation of the posterior sensory nerves supplying the joint is an established treatment option before arthrodesis. We report the successful application of MR-HIFU in a patient with therapy-refractory pain using the Sonalleve MR-HIFU system. The outpatient procedure was performed under spinal anaesthesia and analgosedation. The ramus dorsalis of L5 as well as the lateral branches of the ramus dorsalis S1-S3 was targeted, and tissue peak temperature per sonication was controlled using MR-thermometry. There were no post-interventional complications. Clinical improvement began 4 days post-intervention with complete resolution of the pain after 1 month.
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http://dx.doi.org/10.1007/s00270-019-02263-0DOI Listing
September 2019

Mid-term results of MR-guided high-intensity focused ultrasound treatment for relapsing superficial desmoids.

Int J Hyperthermia 2019 ;36(1):538-542

a Department of Radiology and Nuclear Medicine , Canton Hospital Winterthur , Winterthur , Switzerland.

Purpose: Desmoids are locally infiltrative, nonmalignant soft tissue tumors. Surgery, radiation therapy, and chemotherapy have been the mainstay of treatment, but relapse is common and side effects can result in significant morbidity. MR-HIFU is increasingly recognized as an alternative treatment modality. We assessed the success rate of MR-HIFU for the treatment of extra-abdominal desmoids at our institute.

Materials And Methods: Five patients with relapsing desmoid tumors (three males, two females; age range 40-79 years) were treated using the Sonalleve system in an outpatient setting without general anesthesia. Changes in total tumor volumes were measured with a tumor tracking software. Adverse events were documented.

Results: MR-HIFU was successful in all patients without severe side effects. Follow up ranged from 13 to 60 months. Three patients required more than one treatment session. In 3 patients with small lesions (mean = 9.7 mL), complete ablation was achieved with no evidence of viable tumor on follow up MRI at an average of 35.7 months, while in two patients with larger lesions (mean = 46 mL) the targeted tumor volumes decreased by 73% at 14 months. Skin injuries comprised first- and second-degree burns and were observed with short distance to skin (mean = 0.9 cm) and proximity to bone (i.e. ribs). Skin burns healed within weeks with topical treatment.

Conclusion: MR-HIFU shows good mid-term result for extra-abdominal desmoids with complete response for small lesions and stabilization of larger lesions. MR-HIFU for desmoids can be performed under regional anesthesia/sedation as outpatients.
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December 2019

MR imaging of pubic symphysis after uncomplicated vaginal delivery and planned caesarean delivery in the first postpartum week.

Clin Imaging 2019 Jul - Aug;56:58-62. Epub 2019 Mar 19.

Radiology, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland; University of Zurich, Faculty of Medicine, Zurich, Switzerland.

Purpose: To compare changes in the pubic symphysis between women with vaginal delivery and women with caesarean sections within the first postpartum week.

Materials And Methods: After institutional review board approval 30 healthy women were prospectively examined with MRI (transverse STIR-sequence) three days after delivery. 17 women with vaginal delivery (mean age 33.2 ± 4 years) and 13 with caesarean delivery (35.2 ± 5.6 years) were compared by two musculoskeletal radiologists. Bone marrow edema (location and extent), fluid in the joint gap, joint space width and stress fractures were assessed.

Results: Prevalence of bone marrow edema was high and not different between groups (13/17 (76.5%) vaginal deliveries) and 10/13 (76.9% caesarean deliveries) for reader 1 (p = 0.992) and 14/17 (82.4%) and 10/13 (76.9%) for reader 2 (p = 0.762). Size of bone marrow edema was not statistically significantly different for both readers (results reader 1: right side 2.5 ± 3.3 mm vs. 6.3 ± 7.3 mm, p = 0.300; left side 3.4 ± 4.1 mm vs. 4.1 ± 4.6 mm, p = 0.837). Fluid in the joint was seen in 4/17 (23.5%) vs. 2/13 (15.4%) (p = 0.580) for reader 1 (similar for reader 2). Joint space width did not differ between groups (2.6 ± 0.7 mm vs. 3.1 ± 1.2 mm, p = 0.198). Pubic symphysis diastasis (joint space width > 10 mm) was not observed. Interreader agreement for these parameters was substantial to almost perfect (0.671-0.984, kappa values/intraclass correlation). Reader 1 found no stress fractures, while reader 2 suspected 1 stress fracture on a right pubic bone in a woman after caesarean delivery.

Conclusions: Pubic bone marrow edema is present in 3 of 4 women in the first postpartum week unrelated to the delivery mode.
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http://dx.doi.org/10.1016/j.clinimag.2019.03.009DOI Listing
November 2019

Multi loop snare technique for difficult inferior vena cava filter retrievals.

CVIR Endovasc 2018 20;1(1):33. Epub 2018 Dec 20.

Institute of Radiology and Nuclear Medicine, Kantonsspital Winterthur, Brauerstrasse 15, 8405 Winterthur, Switzerland.

Introduction: Use of optional vena cava filters has steadily increased. In the majority of cases removal is successful using standard techniques. In cases of tilting and migration of the filter however, more advanced techniques are necessary. The "loop-snare" technique has been described for such cases. Difficulties arise when the loop starts to slip around the legs and arms of the filter.

New Technique: We present an improved loop-snare technique which allows to retrieve IVC filters when the simple loop-snare technique fails. We used additional loops, in one case one additional loop in another case two additional loops around the filter tip which allowed successful retrieval. The additional loops were created with a reversed shaped catheter. All guidewires were then engaged with a snare and pulled into a large sheath. The additional loops stabilize the tip and the filter can be pulled into the sheath.

Conclusion: The "multiple-loop-snare" technique is a refinement of the previously described "single loop-snare" technique and can be used when one loop fails.
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http://dx.doi.org/10.1186/s42155-018-0042-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6319532PMC
December 2018

Postpartum Bone Marrow Edema at the Sacroiliac Joints May Mimic Sacroiliitis of Axial Spondyloarthritis on MRI.

AJR Am J Roentgenol 2018 12 24;211(6):1306-1312. Epub 2018 Sep 24.

1 Department of Radiology, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland.

Objective: The objective of our study was to compare MRI findings in the sacroiliac joints of postpartum women (as a model of mechanical changes) and women with known axial spondyloarthritis (as an inflammatory model).

Subjects And Methods: For this prospective multicenter age-matched, case-control study, sacroiliac joint MRI examinations of 30 healthy women (mean age, 34.0 years) in the early postpartum period (mechanical group) and 30 age-matched women (mean age, 33.8 years) with known axial spondyloarthritis (retrospective inflammatory group) were compared. Blinded to clinical information, readers assessed MR images using the following scoring systems: Spondyloarthritis Research Consortium of Canada (SPARCC) MRI index, Berlin method, Assessment of Spondyloarthritis International Society (ASAS) criteria, and SPARCC MRI structural score. Descriptive statistics as percentages of the different findings (i.e., bone marrow edema [BME], erosion, fatty bone marrow replacement, backfill, ankylosis) and scores between groups and between delivery modes were compared.

Results: In the postpartum group, 63.3% (19/30) of women showed BME around the sacroiliac joints compared with 86.7% (26/30) of women in the spondyloarthritis group (based on ASAS criteria). Erosions were uncommon in the postpartum group (10.0% [3/30] postpartum vs 56.7% [17/30] spondyloarthritis). Fatty bone marrow replacement, backfill, and ankylosis were not seen in the postpartum group. In subjects with positive MRI findings for sacroiliitis based on ASAS criteria, the SPARCC MRI index (mean ± SD, 13.6 ± 14.5 vs 13.0 ± 10.7; p = 0.818) and Berlin method (4.5 ± 3.0 and 5.5 ± 3.5, p = 0.378) were not different between the postpartum and spondyloarthritis groups. Scores were not different between birth modalities.

Conclusion: Pregnancy-induced BME at the sacroiliac joints, as a result of prolonged mechanical stress, was present in 63.3% of women who underwent MRI during the early postpartum period and may mimic sacroiliitis of axial spondyloarthritis.
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http://dx.doi.org/10.2214/AJR.17.19404DOI Listing
December 2018

Acute Abdomen: A Rare Case of Ruptured Hepatocellular Carcinoma.

Case Rep Gastroenterol 2017 Jan-Apr;11(1):155-161. Epub 2017 Mar 21.

fDepartment of Surgery, Spital Linth, Uznach, Switzerland.

Spontaneous ruptures of hepatocellular carcinoma (HCC) are rare. Nevertheless they may lead to difficult decisions in the emergency situation. The acute therapies include conservative treatment, transarterial embolization and surgery. Curative treatment of HCC can be achieved by liver resection solely. The decision-making depends on prognostic patient's factors, such as hepatic viral infection status, Child-Pugh grade, liver cirrhosis and number of tumors. In this case transarterial embolization was preferable as a bridging therapy prior to further diagnostics and therapy, to lower the perioperative morbidity and mortality. The therapy of these cases needs an interdisciplinary approach to choose the best possible procedure in each case.
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http://dx.doi.org/10.1159/000463378DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5478187PMC
March 2017

Fully navigated 3 T proton magnetic resonance spectroscopy of liver metastases with inner-volume saturation.

Abdom Radiol (NY) 2017 11;42(11):2615-2622

Institute of Radiology and Nuclear Medicine, Clinical Research Unit, Hirslanden Hospital St. Anna, Lucerne, Switzerland.

Purpose: To demonstrate that fully navigated magnetic resonance spectroscopy (MRS) with inner-volume saturation (IVS) at 3 T results in high-quality spectra that permit evaluating metabolic changes in hepatic metastases without the need for patient compliance.

Methods: Nine patients with untreated, biopsy-proven large hepatic metastases (minimum diameter of 3 cm) were included. In each patient, localized proton MRS was performed in the metastatic lesion and in uninvolved liver parenchyma. To improve quality and consistency of proton MRS, navigator gating was thereby performed not only during acquisition of the spectroscopic data but also during localization imaging and throughout the preparation phases. IVS was utilized to reduce chemical shift displacement between different metabolites and to diminish flow artifacts. Metabolite quantities were normalized relative to the unsuppressed water peak and choline-containing compounds (CCC) to lipid ratios were determined. Wilcoxon signed-rank tests were used to assess differences in the amounts of lipids and CCC as well as the CCC-to-lipid ratios between liver metastases and normal-appearing liver parenchyma.

Results: Fully navigated point-resolved spectroscopy with IVS resulted in high-quality spectra in all patients. Navigator gating during localization imaging and spectroscopic acquisition thereby ensured a precise localization of the spectroscopic voxel. Decreased quantities of lipid and CCC were observed in metastatic tissue compared with uninvolved liver parenchyma. However, the latter trend fell short of statistical significance. Moreover, elevated levels of the CCC-to-lipid ratios were detected in metastatic tissue relative to normal-appearing liver parenchyma.

Conclusions: The present study demonstrates that fully navigated MRS of the liver with IVS at 3 T allows for a precise localization of the spectroscopic voxel and results in high-quality spectra that permit evaluating liver metabolism without the need for patient compliance.
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http://dx.doi.org/10.1007/s00261-017-1173-9DOI Listing
November 2017

Evaluation of a Bioabsorbable Self-Expandable Vein Stent-Base Made of Poly(L-lactide) In Vitro and In Vivo.

Cardiovasc Intervent Radiol 2017 Jan 4;40(1):112-119. Epub 2016 Nov 4.

William Cook Europe, Sandet 6, 4632, Bjæverskov, Denmark.

Purpose: This study was designed to evaluate performance and tissue response to a self-expandable bioabsorbable vein stent-base cut from a tube with enhanced stiffness and strength in vitro and in vivo.

Methods: A diamond-shaped stent-base was cut from a sequential biaxially strained poly(L-lactide) (PLLA) tube for optimized performance. The performance of the stent-base was evaluated in a finite element analysis model, and validation was attempted in vitro through a cyclic flat-plate compression and radial force measurement. The performance of the stent-base was tested in vivo using 3 sheep with 2 implants each for 2 and 3½ weeks, respectively.

Results: In vitro the stent-base showed an elliptical deformation but no fractures. In vivo the stent-base showed adequate radial force and no migration. All implanted stent-bases showed multiple fractures not only at the predicted stress zones but at all connecting points. Fragments of the caudal stent-base stayed in the vein wall indicating sufficient tissue coverage to avoid embolization of the fractured stent pieces, whereas fragments from the cranial device remaining were few. Neointima formation was confirmed histologically at 2 and 3½ weeks.

Conclusion: A bioabsorbable self-expandable stent-base made from PLLA for large veins seems feasible, but over time, the PLLA used in this study appears too stiff and lacks the sufficient flexibility to move with the vena cava, causing multiple fractures.
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http://dx.doi.org/10.1007/s00270-016-1491-2DOI Listing
January 2017
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