Apparent diffusion coefficients (ADC) in response assessment of transarterial radioembolization (TARE) for liver metastases of neuroendocrine tumors (NET): a feasibility study.

BACKGROUND: In patients with hepatic neuroendocrine tumors (NETs) locoregional therapies such as transarterial radioembolization (TARE) are increasingly applied. Response evaluation remains challenging and previous studies assessing response with diffusion-weighted imaging (DWI) have been inconclusive. PURPOSE: To perform a feasibility study to evaluate if response assessment with quantitative apparent diffusion coefficient (ADC) in patients with liver metastases of NETs after TARE will be possible. MATERIAL AND METHODS: Retrospectively, 43 patients with 120 target lesions who obtained abdominal magnetic resonance imaging (MRI) with DWI 39±28 days before and 74±46 days after TARE were included. Intralesional ADC (ADCmin, ADCmax, and ADCmean) were measured for a maximum number of three lesions per patient on baseline and post-interventional DWI. Tumor response was categorized according to RECIST 1.1 and mRECIST. RESULTS: TARE resulted in partial remission (PR) in 23% (63%), in stable disease (SD) in 73% (23%), in progressive disease (PD) in 5% (7%) and in complete response (CR) in 0% (1%) according to RECIST 1.1 (mRECIST, respectively). ADC values increased significantly (P<0.005) after TARE in the PR group whereas there was no significant change in the PD group. Post-therapeutic ADC values of SD lesions increased significantly when evaluated by RECIST 1.1 but not if evaluated by mRECIST. Percentual changes of ADCmean values were slightly higher for responders compared to non-responders (P<0.05). CONCLUSION: ADC values seem to represent an additional marker for treatment response evaluation after TARE in patients with secondary hepatic NET. A conclusive study seems feasible though patient-based evaluation and overall survival and progression free survival as alternate primary endpoints should be considered.

Whole-body magnetic resonance imaging (WBMRI) versus whole-body computed tomography (WBCT) for myeloma imaging and staging.

Myeloma-associated bone disease (MBD) develops in about 80-90% of patients and severely affects their quality of life, as it accounts for the majority of mortality and morbidity. Imaging in multiple myeloma (MM) and MBD is of utmost importance in order to detect bone and bone marrow lesions as well as extraosseous soft-tissue masses and complications before the initiation of treatment. It is required for determination of the stage of disease and aids in the assessment of treatment response. Whole-body low-dose computed tomography (WBLDCT) is the key modality to establish the initial diagnosis of MM and is now recommended as reference standard procedure for the detection of lytic destruction in MBD. In contrast, whole-body magnetic resonance imaging (WBMRI) has higher sensitivity for the detection of focal and diffuse plasma cell infiltration patterns of the bone marrow and identifies them prior to osteolytic destruction. It is recommended for the evaluation of spinal and vertebral lesions, while functional, diffusion-weighted MRI (DWI-MRI) is a promising tool for the assessment of treatment response. This review addresses the current improvements and limitations of WBCT and WBMRI for diagnosis and staging in MM, underlining the fact that both modalities offer complementary information. It further summarizes the corresponding radiological findings and novel technological aspects of both modalities.

Injuries of the isolated larynx-hyoid complex in post-mortem computed tomography (PMCT) and post-mortem fine preparation (PMFP) - a comparison of 54 forensic cases.

OBJECTIVES: To assess the diagnostic accuracy (ACC) of post-mortem computed tomography (PMCT) for fractures of the isolated larynx-hyoid complex (LHC) in comparison to post-mortem fine preparation (PMFP). METHODS: This monocentric prospective study enclosed 54 LHCs that were extracted during autopsy, fixed in formalin, and underwent a PMCT scan (64-row multidetector CT, helical pitch). Two radiologists independently analyzed the LHC scans for image quality (IQ) and fractures (4-point Likert scales). A specialized forensic preparator dissected the specimens under the stereomicroscope. The PMFP results were standardized documented, and used as the standard of reference for the comparison to PMCT. RESULTS: The PMCT-IQ of 95% of the LHC images was rated as good or excellent. IQ was decreased by decay, incisions during autopsy, and separation of the hyoid from the cartilaginous components in 7, 3, and 12 specimens, respectively. PMFP detected 119 fractures in 34 LHCs (63.0%). PMCT identified 91 fractures in 32 specimens (59.3%). PMFP and PMCT significantly agreed concerning the location (Cohen's κ = 0.762; p < 0.001) and the degree of dislocation (κ = 0.689; p < 0.001) of the fractures. Comparing PMCT to PMFP resulted in a sensitivity of 88.2%, a specificity of 90.0%, and an ACC of 88.9% for the LHC. The ACCs for the hyoid, thyroid, and cricoid were 94.4%, 87.0%, and 81.5%, respectively. PMCT procedure was significantly faster than PMFP (28.9 ± 4.1 min vs. 208.2 ± 32.5 min; p < 0,001). CONCLUSIONS: PMCT can detect distinct injuries of the isolated LHC and may promptly confirm violence against the neck as cause of death. PMFP outmatches PMCT in the detection of decent injuries like tears of the cricoid cartilage. KEY POINTS: • Post-mortem computed tomography is able to assess fractures of the larynx-hyoid complex. • Prospective monocentric in vitro study showed that post-mortem computed tomography of the larynx-hyoid complex is faster than post-mortem fine preparation. • Post-mortem computed tomography can confirm violence against the neck as cause of death.

Contrast-enhanced modified 3D T1-weighted TSE black-blood imaging can improve detection of infectious and neoplastic meningitis.

OBJECTIVES: To evaluate the diagnostic value of a contrast-enhanced 3D T1-weighted-modified volumetric isotropic turbo spin-echo acquisition sequence (T1-mVISTA) in comparison with a conventional 3D T1-weighted magnetization-prepared rapid gradient-echo (T1-MP-RAGE) sequence for the detection of meningeal enhancement in patients with meningitis. METHODS: Thirty patients (infectious meningitis, n = 12; neoplastic meningitis, n = 18) and 45 matched controls were enrolled in this retrospective case-control study. Sets of randomly selected T1-mVISTA and T1-MP-RAGE images (both with 0.8-mm isotropic resolution) were read separately 4 weeks apart. Image quality, leptomeningeal and dural enhancement, grading of visual contrast enhancement, and diagnostic confidence were compared using the Kruskal-Wallis rank sum test. RESULTS: Image quality was rated to be good to excellent in 75 out of 75 cases (100%) for T1-mVISTA and 74 out of 75 cases (98.7%) for T1-MP-RAGE. T1-mVISTA detected significantly more patients with leptomeningeal enhancement (p = 0.006) compared with T1-MP-RAGE (86.7 vs. 50.0%, p < 0.001), each with specificity of 100%. Similarly, sensitivity of T1-mVISTA for the detection of dural and/or leptomeningeal enhancement was also significantly higher compared with that of T1-MP-RAGE (96.7 vs. 80.0%, p = 0.025) without significant differences regarding specificity (97.8 vs. 95.6%, p = 0.317). No significant differences were found for dural enhancement alone. Diagnostic confidence in T1-mVISTA was significantly higher (p = 0.01). Visual contrast enhancement was tendentially higher in T1-mVISTA. CONCLUSIONS: T1-mVISTA may be an adequate and probably better alternative to T1-MP-RAGE for detection of leptomeningeal diseases. KEY POINTS: • Black-blood T1-mVISTA showed a significant higher sensitivity for the detection of leptomeningeal enhancement compared with MP-RAGE without losses regarding specificity. • Diagnostic confidence was assessed significantly higher in T1-mVISTA. • T1-mVISTA should be considered a supplement or an alternative to T1-MP-RAGE in patients with suspected leptomeningeal diseases.

3D black-blood 3T-MRI for the diagnosis of abdominal large vessel vasculitis.

OBJECTIVES: To assess the value of a T1-3D black-blood turbo spin echo (TSE) sequence for the diagnosis of abdominal large vessel vasculitis (LVV). MATERIALS AND METHODS: The study included 20 patients with abdominal LVV and 17 controls, who underwent a 3T-MRI scan using a modified T1-3D volumetric isotropic TSE acquisition and a segmented T1-3D turbo field echo sequence (T1-mVISTA/T1-eTHRIVE). Two radiologists independently analyzed the aorta for concentric contrast enhancement, concentric wall thickening, image quality, and flow artifact intensity (CCE/CWT/IQ/FAI; 4-point scales). The mean aortic wall thickness (MAWT) in post-contrast T1-mVISTA was compared between patients and controls. RESULTS: IQ of T1-mVISTA was rated good to excellent in 91.5% of 282 evaluated vessel segments with no or minor FAI present in 85.5%. The inter-observer reproducibility for the identification of CCE/CWT on T1-mVISTA was 0.92 and 0.93 (p < 0.001). The distribution of segmental inflammation in T1-mVISTA significantly correlated with T1-eTHRIVE (CCE, κ = 0.768; CWT, κ = 0.715; p < 0.001), resulting in a sensitivity, specificity, and positive predictive value of 100%, 81.3%, and 83.3%. The MAWT significantly differed between patients and controls (3.29 ± 0.81 vs. 2.24 ± 0.45 mm; p < 0.001). CONCLUSIONS: T1-mVISTA enables the evaluation of the MAWT and allows the detection of abdominal LVV. KEY POINTS: • 3D T1w-mVISTA accurately depicted the large abdominal vessels. • 3D T1w-mVISTA enables accurate measurements of the abdominal aortic wall thickness. • 3D T1w-mVISTA is useful for the detection of abdominal LVV.

Clinical value of [18F]FDG-PET/CT and 3D-black-blood 3T-MRI for the diagnosis of large vessel vasculitis and single-organ vasculitis of the aorta.

BACKGROUND: We aimed to investigate the clinical value of a 3D-T1w turbo-spin-echo (TSE) sequence and [18F]fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG-PET/CT) for the diagnosis of active large vessel vasculitis (LVV) and single-organ vasculitis (SOV) of the aorta. METHODS: Twenty-four patients with suspected vasculitis who underwent MRI and PET/CT were retrospectively evaluated. MRI was analyzed for concentric contrast enhancement and wall thickening, and flow artifact intensity (4-point-scales). PET/CT analysis comprised qualitative, quantitative and semiquantitative methods. Imaging findings were correlated with final diagnosis derived from the clinical follow-up data. RESULTS: Fifteen of 24 patients had a clinically confirmed active vasculitis, two had inactive vasculitis and 7 no vasculitis. [18F]FDG-PET/CT and 3D-T1w TSE-MRI revealed both a high diagnostic accuracy of 88% and 83%, respectively. In patients in whom both PET/CT and MRI showed concordant findings (19 patients), the accuracy increased to 95% with a high positive predictive value (92%) and negative predictive value (100%); thus, a correct diagnosis was obtained in 18 of 19 patients. Among the five patients with discordant findings PET/CT correctly identified the two patients without active vasculitis while rated false positive on MRI. Of the three remaining patients with active vasculitis, two were correctly identified by MRI and one by PET/CT. CONCLUSIONS: 3D-T1w TSE-MRI and [18F]FDG-PET/CT are both useful in the diagnosis of active vasculitis with high diagnostic accuracies. The diagnostic accuracy was even optimized by combining the two analysis methods. Therefore, there might be substantial potential for the application of whole-body hybrid PET/MRI in the evaluation of vasculitis in future studies.

Assessment of Disease Activity in Takayasu Arteritis: Potential Role of Contrast-Enhanced Ultrasound.

PURPOSE: To assess the diagnostic value of intima media thickness measurements and contrast-enhanced ultrasound (CEUS) of the supraaortic arteries in the assessment of disease activity in Takayasu arteritis (TA). MATERIALS AND METHODS: Patients with TA and involvement of the carotid and/or subclavian/axillary arteries underwent CEUS imaging in addition to B-mode and color duplex ultrasound. The maximum IMT (mIMT) was measured and high-resolution CEUS of the most prominently thickened vessel segment was performed. Two blinded readers reviewed the CEUS movies, with semiquantitative assessment of microbubble enhancement of the arterial wall (grade 0: no or minimal; grade 1: moderate; grade 2: pronounced). Clinical symptoms, acute phase reactants, and established indices of clinical disease activity (NIH criteria, ITAS score) were recorded. RESULTS: 40 examinations in 17 patients were analyzed. According to clinical judgement, 27 and 13 cases were classified as clinically inactive and active, respectively. An mIMT-cutoff of > 2.7 mm identified active disease with a sensitivity and specificity of 69.2 % and 88.9 %, respectively (area under the curve 0.83). The interobserver agreement of CEUS analysis was substantial (Cohen's kappa 0.76). By consensus reading, 17, 15, and 8 cases were classified as uptake grade 0, grade 1 and grade 2, respectively. Grade 0 uptake was exclusively present in 17 clinically inactive patients. Grade 1 uptake was seen in 10 patients with clinically inactive disease and 5 patients with clinically active disease. Grade 2 uptake was exclusively present in 8 patients with active disease. CONCLUSION: Both sonographic IMT measurements and high-resolution CEUS are promising in the ad-hoc assessment of disease activity in patients with TA.

Relapses in three patients with Takayasu arteritis under tocilizumab treatment detected by contrast enhanced ultrasound.

Takayasu arteritis (TA) is a rare large vessel vasculitis, affecting the aorta and its major branches, typically in young women. In this case report, we present three cases of young women of Caucasian descent who experienced relapses while under treatment with the monoclonal humanized antibody to the interleukin 6 receptor, tocilizumab. Active vasculitic lesions of the supraaortic (common carotid and axillary) arteries were detected and characterized via high resolution contrast enhanced ultrasound. Based on these cases, we discuss the potential role of contrast enhanced ultrasound in the diagnosis and follow-up of TA as well as the current data on the efficacy of tocilizumab in the treatment of TA.

Evolution of patency rates of self-expandable bare metal stents for endovascular treatment of femoro-popliteal arterial occlusive disease: Does stent design matter?

OBJECTIVE: To analyse the patency rates of femoro-popliteal stenting with different self-expandable Nitinol stent-designs. METHODS: Two hundred and twenty-two patients (142 (64%) male; age 72.4 ± 11.6 years) with symptomatic femoro-popliteal peripheral arterial occlusive disease (PAOD) underwent percutaneous transluminal angioplasty (PTA) and stenting with three different Nitinol stents (interwoven IW: n = 70; closed-cell CC: n = 85; open-cell OC: n = 67). One-year post-procedural target lesion revascularization (TLR_12M) rates were investigated with regard to co-morbidities: diabetes (DBM), hyperlipidaemia (HLP), hypertension (RR), coronary artery disease (CAD) and degree of calcification. RESULTS: Twelve-month follow-up data were available for 60, 69 and 50 patients in the IW, OC and CC groups (179 patients in total). The cumulative patency (IW: 52 (86.7%); OC: 50 (72.5%); CC: 23 (46.0%); P < 0.001) and the TLR_12M rates (IW: 8 (13.3%); OC: 19 (27.5%); CC: 27 (54.0%); P < 0.001) differed significantly, as did the subgroup analyses (DBM: P = 0.05; RR: P = 0.003; HLP: P = 0.005; CAD: P = 0.02; localization: P < 0.001; calcification: P < 0.001), with the best patency for the IW stent and the highest TLR_12M for the CC stent. CONCLUSION: The interwoven stent-design was superior to the standard open- and closed-cell stent-designs in endovascular treatment of femoro-popliteal PAOD in a follow-up period of 12 months. KEY POINTS: • Results of femoro-popliteal stenting are still unsatisfactory. • Comparative studies for currently available different Nitinol stent-designs are lacking. • This is a first comparative study on long-term patency of different Nitinol stent-designs. • Interwoven stent-design leads to improved long-term patency. • Interwoven stent-design leads to lower TLR than other stent-designs.

3D-black-blood 3T-MRI for the diagnosis of thoracic large vessel vasculitis: A feasibility study.

OBJECTIVES: To evaluate the feasibility of T1w-3D black-blood turbo spin echo (TSE) sequence with variable flip angles for the diagnosis of thoracic large vessel vasculitis (LVV). METHODS: Thirty-five patients with LVV, diagnosed according to the current standard of reference, and 35 controls were imaged at 3.0T using 1.2 × 1.3 × 2.0 mm3 fat-suppressed, T1w-3D, modified Volumetric Isotropic TSE Acquisition (mVISTA) pre- and post-contrast. Applying a navigator and peripheral pulse unit triggering (PPU), the total scan time was 10-12 min. Thoracic aorta and subclavian and pulmonary arteries were evaluated for image quality (IQ), flow artefact intensity, diagnostic confidence, concentric wall thickening and contrast enhancement (CWT, CCE) using a 4-point scale. RESULTS: IQ was good in all examinations (3.25 ± 0.72) and good to excellent in 342 of 408 evaluated segments (83.8 %), while 84.1 % showed no or minor flow artefacts. The interobserver reproducibility for the identification of CCE and CWT was 0.969 and 0.971 (p < 0.001) with an average diagnostic confidence of 3.47 ± 0.64. CCE and CWT were strongly correlated (Cohen's k = 0.87; P < 0.001) and significantly more frequent in the LVV-group (52.8 % vs. 1.0 %; 59.8 % vs. 2.4 %; P < 0.001). CONCLUSIONS: Navigated fat-suppressed T1w-3D black-blood MRI with PPU-triggering allows diagnosis of thoracic LVV. KEY POINTS: • Cross-sectional imaging is frequently applied in the diagnosis of LVV. • Navigated, PPU-triggered, T1w-3D mVISTA pre- and post contrast takes 10-12 min. • In this prospective, single-centre study, T1w-3D mVISTA accurately depicted large thoracic vessels. • T1w-3D mVISTA visualized CWT/CCW as correlates of mural inflammation in LVV. • T1w-3D mVISTA might be an alternative diagnostic tool without ionizing radiation.

B-mode sonography wall thickness assessment of the temporal and axillary arteries for the diagnosis of giant cell arteritis: a cohort study.

OBJECTIVES: We aimed to determine the diagnostic accuracy of B-mode compression sonography of the temporal arteries (tempCS) and B-mode sonographic measurement of the axillary artery intima media thickness (axIMT) for the diagnosis of giant cell arteritis (GCA). METHODS: After having established measurement of tempCS and axIMT in our routine diagnostic workup, 92 consecutive patients with a suspected diagnosis of GCA were investigated. Clinical characteristics were recorded and wall thickening of the temporal arteries (tempCS) and axillary arteries (axIMT) was measured (mm). Using the final clinical diagnosis as the reference standard, receiver operator characteristics (ROC) analysis was performed. In a subgroup of 26 patients interobserver agreement was assessed using Spearman's rank correlation. RESULTS: Cranial GCA, extracranial GCA, and combined cranial/extracranial GCA were diagnosed in 18, 7, and 9 individuals, respectively. For the diagnosis of cranial GCA, tempCS had an excellent area under the curve (AUC) of 0.95, with a cut-off of ≥0.7 mm offering a sensitivity and specificity of 85% and 95%. The AUC of axIMT for the diagnosis of extracranial GCA was 0.91 (cut-off ≥1.2 mm: sensitivity and specificity 81.3 and 96.1%). Applying a combined tempCS/axIMT cut-off of ≥0.7mm/1.2 mm, we calculated an overall sensitivity and specificity for the final clinical diagnosis of cranial and/or extracranial GCA of 85.3% and 91.4%. Interobserver agreement was strong for both parameters assessed (Spearman's rho 0.72 and 0.77, respectively). CONCLUSIONS: The combination of tempCS/axIMT allows objective sonographic assessment in suspected GCA with promising diagnostic accuracy.

Safety and efficiency of femoral artery access closure with a novel biodegradable closure device: a prospective single-centre pilot study.

OBJECTIVES: Vascular closure devices can accelerate haemostasis after arteriotomy, but induce scarring. The aim of the study was to prospectively analyse the feasibility of a novel biodegradable arterial closure device (CD). METHODS: Two hundred fifty-five patients (183 male; age 36-98 years) with an access vessel diameter >3 mm received the biodegradable CD after endovascular therapy. Technical success rate, time-to-haemostasis (TTH) and time-to-ambulation (TTA) were measured. Puncture site complications were categorized as minor (local hematoma, minor bleeding) or major (pseudoaneurysm, embolization, dissection, thrombotic occlusion, hematoma/major bleeding requiring surgery, access site infection). RESULTS: Technical success was achieved in 98.8 % (252 cases); device failure occurred in three cases (1.2 %). The average TTH and TTA were 11.3 ± 26.9 s and 73.0 ± 126.3 min. The major complication rate was 1.6 %, with three pseudoaneurysms and one retroperitoneal bleeding. The minor complication rate was 2.0 %, with five small hematomas. Neither cardiovascular risk factors nor access vessel characteristics had statistically significant influence on adverse events. Re-puncture was uncomplicated in 32 cases after 155.0 ± 128.8 days. CONCLUSIONS: Handling of the new biodegradable CD is safe. The complication rates are tolerably low and comparable to other CDs. Post-procedural sonography showed no significant palpable subcutaneous changes in the access site. KEY POINTS: • VCDs can increase time efficiency and patient comfort after intervention. • In this prospective single-centre-study, biodegradable CD was safe and easily applicable. • Its major and minor complication rates are comparable to other CDs. • Its mean time-to-haemostasis and time-to-ambulation were 11.3 ± 26.9 s and 73.0 ± 126.3 min. • Post-procedural sonography showed no significant palpable subcutaneous changes at the access site.

Treatment of male varicoceles by transcatheter polidocanol foam sclerotherapy: evaluation of clinical success, complications, and patients' satisfaction with regard to alternative techniques.

OBJECTIVES: We report our experience with polidocanol foam sclerotherapy with no additional coils, evaluating clinical success, patients' satisfaction, and complications. METHODS: We conducted a retrospective study of 141 patients with 146 varicoceles (mean age: 29.3 years; range: 13 - 60 years) who underwent foam sclerotherapy with polidocanol 2% (range: 2 - 12 ml) in an outpatient setting between January 2007 and December 2013. For the follow-up, telephone interviews with the patients were conducted (mean follow-up time: 46.4 months, standard deviation: 20.17 months). RESULTS: The technical success rate was 91.8%. There was a 55.8% response rate to the telephone interviews. Follow-up revealed a clinical success rate of 83.9% and a persistence or relapse rate of 16.1%. Of the patients, 81.9% were absolutely satisfied with the outcome. In 94.9% of cases, pain or discomfort resolution was reported, and in 97% of cases, aesthetic issues were no longer a problem. Of partners, 63.2% achieved pregnancy, and in 50% of patients with preprocedural testicular atrophy, catch-up growth was observed. One patient with pampiniform plexus phlebitis received inpatient treatment with no long-term damage recorded. CONCLUSIONS: Polidocanol foam varicocele sclerotherapy is a safe and effective procedure, with a high rate of patients' satisfaction, clinical and technical success, and considerable catch-up growth and pregnancy achievement. KEY POINTS: • Varicocele treatment using polidocanol foam sclerotherapy is a safe and effective procedure. • It is easily feasible in an outpatient setting. • The clinical and technical success rates are high. • It shows a high rate of patients' satisfaction and symptom resolution. • Postinterventional catch-up growth and pregnancy achievement are considerable.

Reduction of CT beam hardening artefacts of ethylene vinyl alcohol copolymer by variation of the tantalum content: evaluation in a standardized aortic endoleak phantom.

OBJECTIVES: Our aim was to develop an aortic stent graft phantom to simulate endoleak treatment and to find a tantalum content (TC) of ethylene-vinyl-alcohol-copolymer that causes fewer computed tomography (CT) beam hardening artefacts, but still allows for fluoroscopic visualization. METHODS: Ethylene-vinyl-alcohol-copolymer specimens of different TC (10-50 %, and 100 %) were injected in an aortic phantom bearing a stent graft and endoleak cavities with simulated re-perfusion. Fluoroscopic visibility of the ethylene-vinyl-alcohol-copolymer specimens was analyzed. In addition, six radiologists analyzed endoleak visibility, and artefact intensity of ethylene-vinyl-alcohol-copolymer in CT. RESULTS: Reduction of TC significantly decreased CT artefact intensity of ethylene-vinyl-alcohol-copolymer and increased visibility of endoleak re-perfusion (p < 0.000). It also significantly decreased fluoroscopic visibility of ethylene-vinyl-alcohol-copolymer (R = 0.883, p ≤ 0.01), and increased the active embolic volumes prior to visualization (Δ ≥ 40 µl). Ethylene-vinyl-alcohol-copolymer specimens with a TC of 45-50 % exhibited reasonable visibility, a low active embolic volume and a tolerable CT artefact intensity. CONCLUSIONS: The developed aortic stent graft phantom allows for a reproducible simulation of embolization of endoleaks. The data suggest a reduction of the TC of ethylene-vinyl-alcohol-copolymer to 45 -50 % of the original, to interfere less with diagnostic imaging in follow-up CT examinations, while still allowing for fluoroscopic visualization.

Typical exposure parameters, organ doses and effective doses for endovascular aortic aneurysm repair: Comparison of Monte Carlo simulations and direct measurements with an anthropomorphic phantom.

OBJECTIVES: Radiation exposure of patients during endovascular aneurysm repair (EVAR) procedures ranks in the upper sector of medical exposure. Thus, estimation of radiation doses achieved during EVAR is of great importance. MATERIAL AND METHODS: Organ doses (OD) and effective doses (ED) administered to 17 patients receiving EVAR were determined (1) from the exposure parameters by performing Monte Carlo simulations in mathematical phantoms and (2) by measurements with thermoluminescent dosimeters in a physical anthropomorphic phantom. RESULTS: The mean fluoroscopy time was 26 min, the mean dose area product was 24995 cGy cm2. The mean ED was 34.8 mSv, ODs up to 626 mSv were found. Whereas digital subtraction angiographies (DSA) and fluoroscopies each contributed about 50% to the cumulative ED, the ED rates of DSAs were found to be ten times higher than those of fluoroscopies. Doubling of the field size caused an ED rate enhancement up to a factor of 3. CONCLUSION: EVAR procedures cause high radiation exposure levels that exceed the values published thus far. As a consequence, (1) DSAs should be only performed when necessary and with a low image rate, (2) fluoroscopies should be kept as short as possible, and (3) field sizes should be minimized. KEY POINTS: • During endovascular aneurysm repair (EVAR) considerable patient doses are achieved. • For each EVAR procedure organ (OD) and effective (ED) doses were determined. • The mean ED was 34.8 mSv, the highest OD was 626 mSv. • Number of DSAs, fluoroscopy durations and field sizes should be minimized.

Complications of transbrachial arterial access for peripheral endovascular interventions.

PURPOSE: To prospectively assess current limitations and complication rates of the transbrachial access technique for endovascular treatment of peripheral vascular pathologies. METHODS: In total, 150 patients (112 men; mean age 66.3 ± 10.0 years) with arterial occlusive disease underwent endovascular therapy via a transbrachial access. Periprocedure data (sheath size, dose area product, fluoroscopy time, and procedure duration) were analyzed. Postprocedure complications of the puncture sites were categorized as minor (local hematoma, pseudoaneurysm, embolization, dissection, minor bleeding) and major (thrombotic occlusion, hematoma requiring surgery, major bleeding, nerve injury). RESULTS: The minor and major complication rates were 14.0% (n = 21) and 2.7% (n = 4). The most frequent major complication was thrombotic occlusion of the brachial artery requiring surgical treatment (3/150, 2%). There was only one temporary palsy of the median nerve and no stroke. Local hematoma (15, 10%), pseudoaneurysm (3, 2%), or a combination of both (3, 2%) dominated the minor complications. The average dose area product and fluoroscopy time were 12,752.1 ± 9524.5 cGy*cm(2) and 24.3 ± 18.4 minutes, respectively, though procedure duration was acceptable (121.8 ± 48.9 minutes). CONCLUSION: Complication rates of the transbrachial access for endovascular treatment of peripheral or visceral artery occlusive disease are tolerably low, making it a safe and an important alternative to the transfemoral access in selected cases, though the radiation exposure is rather high.

Role of diffusion-weighted imaging in response prediction and evaluation after high dose rate brachytherapy in patients with colorectal liver metastases.

BACKGROUND: The aim of the study was to assess the role of diffusion-weighted imaging (DWI) to evaluate treatment response in patients with liver metastases of colorectal cancer. PATIENTS AND METHODS: In this retrospective, observational cohort study, we included 19 patients with 18 responding metastases (R-Mets; follow-up at least one year) and 11 non-responding metastases (NR-Mets; local tumor recurrence within one year) who were treated with high-dose-rate brachytherapy (HDR-BT) and underwent pre- and post-interventional MRI. DWI (qualitatively, mean apparent diffusion coefficient [ADCmean], ADCmin, intraindividual change of ADCmean and ADCmin) were evaluated and compared between pre-interventional MRI, first follow-up after 3 months and second follow-up at the time of the local tumor recurrence (in NR-Mets, mean: 284 ± 122 d) or after 12 months (in R-Mets, mean: 387+/-64 d). Sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs) for detection of local tumor recurrence were calculated on second follow up, evaluating (1) DWI images only, and (2) DWI with Gd-enhanced T1-weighted images on hepatobiliary phase (contrast-enhanced [CE] T1-weight [T1w] hepatobiliary phase [hb]). RESULTS: ADCmean significantly increased 3 months after HDR-BT in both groups (R-Mets: 1.48 ± 0.44 and NR-Mets: 1.49 ± 0.19 x 10-3 mm2;/s, p < 0.0001 and p = 0.01), however, intraindividual change of ADCmean (175% vs.127%, p = 0.03) and ADCmin values (0.44 ± 0.24 to 0.82 ± 0.58 x 10-3 mm2/s) significantly increased only in R-Mets (p < 0.0001 and p < 0.001). ADCmin was significant higher in R-Mets compared to NR-Mets on first follow-up (p = 0.04). Sensitivity (1 vs. 0.72), specificity (0.94 vs. 0.72), PPV (0.91 vs. 0.61) and NPV (1 vs. 0.81) could be improved by combining DWI with CE T1w hb compared to DWI only. CONCLUSIONS: DW-MRI seems to be helpful in the qualitative and quantitative evaluation of treatment response after HDR-BT of colorectal metastases in the liver.

Embolic Protection in Complex Femoropopliteal Interventions: Safety, Efficacy and Predictors of Filter Macroembolization.

OBJECTIVES: To evaluate the safety and efficacy of a filter embolic protection device (FEPD) in endovascular interventions of the femoropopliteal arteries. METHODS: Patients who underwent endovascular interventions of the femoropopliteal arteries between 2008 and 2016 and in whom the SpiderFXTM FEPD was applied were included in this retrospective study. Clinical and angiographic characteristics, filter macroembolization (FME), device-related complications, distal embolization, as well as the early clinical and hemodynamic outcome, were assessed. Potential risk factors for FME were evaluated by multivariate analysis. RESULTS: A total of 244 cases were identified (203 patients, claudication 60.4%, critical limb ischaemia 39.6%, mean lesion length 13.2 ± 12.9 cm, complete occlusions in 72.7%). Balloon angioplasty ± stenting (BAP), directional atherectomy ± balloon angioplasty ± stenting (DA) and rotational thrombectomy ± balloon angioplasty ± stenting (RT) were performed in 141, 61 and 42 cases, respectively. FEPD placement and retrieval were successful in all but one case each. Permanent filter-related vessel damage was not observed. The rate of FME was 37.3% (BAP 36.2%, DA 32.8%, RT 47.7%). Risk factors for FME in the BAP- and DA-group were total occlusion, lesion length > 19 cm, visible thrombus and diabetes mellitus. The distal embolization rate despite filter protection was 4.1 % (BAP 4.9%, DA 1.6%, RT 4.8%) and was higher in cases with FME compared with those without FME (8.7% vs. 1.5%, p = 0.02). CONCLUSION: The Spider FXTM device is safe and effective in capturing embolic debris during femoropopliteal interventions. A residual risk of peripheral embolization remains. LEVEL OF EVIDENCE: III, Cohort study.

Imaging characteristics of intravascular spherical contrast agents for grating-based x-ray dark-field imaging - effects of concentrations, spherical sizes and applied voltage.

This study investigates the x-ray scattering characteristics of microsphere particles in x-ray-grating-based interferometric imaging at different concentrations, bubble sizes and tube voltages (kV). Attenuation (ATI), dark-field (DFI) and phase-contrast (PCI) images were acquired. Signal-to-noise (SNR) and contrast-to-noise ratios with water (CNRw) and air as reference (CNRa) were determined. In all modalities, a linear relationship between SNR and microbubbles concentration, respectively, microsphere size was found. A significant gain of SNR was found when varying kV. SNR was significantly higher in DFI and PCI than ATI. The highest gain of SNR was shown at 60 kV for all media in ATI and DFI, at 80 kV for PCI. SNR for all media was significantly higher compared to air and was slightly lower compared to water. A linear relationship was found between CNRa, CNRw, concentration and size. With increasing concentration and decreasing size, CNRa and CNRw increased in DFI, but decreased in PCI. Best CNRa and CNRw was found at specific combination of kV and concentration/size. Highest average CNRa and CNRw was found for microspheres in ATI and PCI, for microbubbles in DFI. Microspheres are a promising contrast-media for grating-based-interferometry, if kV, microsphere size and concentration are appropriately combined.