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1,148 result(s) for "Phlebography"
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A robust multi-scale approach to quantitative susceptibility mapping
Quantitative Susceptibility Mapping (QSM), best known as a surrogate for tissue iron content, is becoming a highly relevant MRI contrast for monitoring cellular and vascular status in aging, addiction, traumatic brain injury and, in general, a wide range of neurological disorders. In this study we present a new Bayesian QSM algorithm, named Multi-Scale Dipole Inversion (MSDI), which builds on the nonlinear Morphology-Enabled Dipole Inversion (nMEDI) framework, incorporating three additional features: (i) improved implementation of Laplace's equation to reduce the influence of background fields through variable harmonic filtering and subsequent deconvolution, (ii) improved error control through dynamic phase-reliability compensation across spatial scales, and (iii) scalewise use of the morphological prior. More generally, this new pre-conditioned QSM formalism aims to reduce the impact of dipole-incompatible fields and measurement errors such as flow effects, poor signal-to-noise ratio or other data inconsistencies that can lead to streaking and shadowing artefacts. In terms of performance, MSDI is the first algorithm to rank in the top-10 for all metrics evaluated in the 2016 QSM Reconstruction Challenge. It also demonstrated lower variance than nMEDI and more stable behaviour in scan-rescan reproducibility experiments for different MRI acquisitions at 3 and 7 Tesla. In the present work, we also explored new forms of susceptibility MRI contrast making explicit use of the differential information across spatial scales. Specifically, we show MSDI-derived examples of: (i) enhanced anatomical detail with susceptibility inversions from short-range dipole fields (hereby referred to as High-Pass Susceptibility Mapping or HPSM), (ii) high specificity to venous-blood susceptibilities for highly regularised HPSM (making a case for MSDI-based Venography or VenoMSDI), (iii) improved tissue specificity (and possibly statistical conditioning) for Macroscopic-Vessel Suppressed Susceptibility Mapping (MVSSM), and (iv) high spatial specificity and definition for HPSM-based Susceptibility-Weighted Imaging (HPSM-SWI) and related intensity projections. [Display omitted] •MSDI mitigates QSM reconstruction artefacts through effective preconditioning.•MSDI leads to accurate and stable QSM across a broad range of imaging conditions.•Multi-scale information enables novel contrasts with greater tissue specificity.
Dynamic multidetector CT and non-contrast-enhanced MR for right adrenal vein imaging: comparison with catheter venography in adrenal venous sampling
Objectives To evaluate visualization of the right adrenal vein (RAV) with multidetector CT and non-contrast-enhanced MR imaging in patients with primary aldosteronism. Methods A total of 125 patients (67 men) scheduled for adrenal venous sampling (AVS) were included. Dynamic 64-detector-row CT and balanced steady-state free precession-based non-contrast-enhanced 3-T MR imaging were performed. RAV visualization based on a four-point score was documented. Both anatomical location and variation on cross-sectional imaging were evaluated, and the findings were compared with catheter venography as the gold standard. Results The RAV was visualized in 93.2 % by CT and 84.8 % by MR imaging ( p  = 0.02). Positive predictive values of RAV visualization were 100 % for CT and 95.2 % for MR imaging. Imaging score was significantly higher in CT than MR imaging ( p  < 0.01). The RAV formed a common trunk with an accessory hepatic vein in 16 % of patients. The RAV orifice level on cross-sectional imaging was concordant with catheter venography within the range of 1/3 vertebral height in >70 % of subjects. Success rate of AVS was 99.2 %. Conclusions Dynamic CT is a reliable way to map the RAV prior to AVS. Non-contrast-enhanced MR imaging is an alternative when there is a risk of complication from contrast media or radiation exposure. Key Points • Dynamic CT and non-contrast-enhanced MR imaging detect the right adrenal vein (RAV). • Dynamic CT can visualize the RAV more than non-contrast-enhanced MR imaging. • Mapping the RAV helps to achieve successful adrenal venous sampling. • Sixteen per cent of RAVs share the common trunk with accessory hepatic veins.
CT venography for the diagnosis of postpartum venous thromboembolism: a prospective multi-center cohort study
Objectives To assess the role of CT venography (CTV) in the diagnosis of venous thromboembolism (VTE) during the postpartum period. Materials and methods This multicenter prospective cohort study was conducted between April 2016 and April 2020 in 14 university hospitals. All women referred for CT pulmonary angiography (CTPA) for suspected pulmonary embolism (PE) within the first 6 weeks postpartum were eligible. All CTPAs were performed on multidetector CT machines with the usual parameters and followed by CTV of the abdomen, pelvis, and proximal lower limbs. On-site reports were compared to expert consensus reading, and the added value of CTV was assessed for both. Results The final study population consisted of 123 women. On-site CTPA reports mentioned PE in seven women (7/123, 5.7%), all confirmed following expert consensus reading, three involving proximal pulmonary arteries and four limited to distal arteries. Positive CTV was reported on-site in nine women, five of whom had negative and two indeterminate CTPAs, bringing the VTE detection rate to 11.4% (14/123) (95%CI: 6.4–18.4, p  = 0.03). Expert consensus reading confirmed all positive on-site CTV results, but detected a periuterine vein thrombosis in an additional woman who had a negative CTPA, increasing the VTE detection rate to 12.2% (15/123) (95%CI: 7.0–19.3, p  = 0.008). Follow-up at 3 months revealed no adverse events in this woman, who was left untreated. Median Dose-Length-Product was 117 mGy.cm for CTPA and 675 mGy.cm for CTPA + CTV. Conclusion Performing CTV in women suspected of postpartum PE doubles the detection of venous thromboembolism, at the cost of increased radiation exposure. Clinical relevance statement CTV can help in the decision-making process concerning curative anticoagulation in women with suspected postpartum PE, particularly those whose CTPA results are indeterminate or whose PE is limited to the subsegmental level. Key Points Postpartum women are at risk of pulmonary embolism, and CT pulmonary angiography can give equivocal results. CT venography (CTV) positivity increased the venous thromboembolism detection rate from 5.7 to 11.4%. CTV may help clinical decision-making, especially in women with indeterminate CTPA results or subsegmental emboli.
A Novel Method of Adrenal Venous Sampling via an Antecubital Approach
Purpose Currently, almost all adrenal venous sampling (AVS) procedures are performed by femoral vein access. The purpose of this study was to establish the technique of AVS via an antecubital approach and evaluate its safety and feasibility. Materials and Methods From January 2012 to June 2015, 194 consecutive patients diagnosed as primary aldosteronism underwent AVS via an antecubital approach without ACTH simulation. Catheters used for bilateral adrenal cannulations were recorded. The success rate of bilateral adrenal sampling, operation time, fluoroscopy time, dosage of contrast, and incidence of complications were calculated. Results A 5F MPA1 catheter was first used to attempt right adrenal cannulation in all patients. Cannulation of the right adrenal vein was successfully performed in 164 (84.5%) patients. The 5F JR5, Cobra2, and TIG catheters were the ultimate catheters for right adrenal cannulation in 16 (8.2%), 5 (2.6%), and 9 (4.6%) patients, respectively. For left adrenal cannulation, JR5 and Cobra2 catheters were used in 19 (9.8%) and 10 (5.2%) patients, respectively, while only TIG catheters were used in the remaining 165 (85.1%) patients. The rate of successful adrenal sampling on the right, left, and bilateral sides was 91.8%, 93.3%, and 87.6%, respectively. The mean time of operation was (16.3 ± 4.3) minutes, mean fluoroscopy time was (4.7 ± 1.3) minutes, and the mean use of contrast was (14.3 ± 4.7) ml. The incidence of adrenal hematoma was 1.0%. Conclusions This study showed that AVS via an antecubital approach was safe and feasible, with a high rate of successful sampling.
Iliac vein compression: epidemiology, diagnosis and treatment
Iliac vein compression (LIVC) is a prevalent finding in the general population, but a smaller number of patients are symptomatic. ILVC should be considered in symptomatic patients with unexplained unilateral lower leg swelling. Patients typically complain of one or more of the following symptoms: lower leg pain, heaviness, venous claudication, swelling, hyperpigmentation and ulceration. ILVC can be thrombotic, combined with acute or chronic DVT, or non-thrombotic. ILVC is best diagnosed with intravascular ultrasound (IVUS), but computed tomography angiography (CTA) and magnetic resonance angiography (MRA) have emerged as valid screening tests. Venography underestimates the severity of ILVC but may provide insights into the anatomy and the presence of collaterals. Based on current available evidence, endovascular therapy with stenting remains the main treatment strategy for ILVC. Dedicated nitinol venous stents are currently under review by the Food and Drug Administration for potential approval in the United States. These stents have been released outside the US. There is no consensus to the optimal anticoagulation regimen post-ILVC stenting. Oral anticoagulants, however, remain a preferred therapy in patients with history of thrombotic ILVC.
Comparison of C-arm computed tomography and on-site quick cortisol assay for adrenal venous sampling: A retrospective study of 178 patients
Objectives To compare the performance of on-site quick cortisol assay (QCA) and C-arm computed tomography (CT) assistance on adrenal venous sampling (AVS) without adrenocorticotropic hormone stimulation. Methods The institutional review board at our hospital approved this retrospective study, which included 178 consecutive patients with primary aldosteronism. During AVS, we used C-arm CT to confirm right adrenal cannulation between May 2012 and June 2015 (n = 100) and QCA for bilateral adrenal cannulation between July 2015 and September 2016 (n = 78). Successful AVS required a selectivity index (cortisol adrenal vein /cortisol peripheral ) of ≥ 2.0 bilaterally. Results The overall success rate of C-arm CT-assisted AVS was 87%, which increased to 97.4% under QCA ( P = .013). The procedure time (C-arm CT, 49.5 ± 21.3 min; QCA, 37.5 ± 15.6 min; P < .001) and radiation dose (C-arm CT, 673.9 ± 613.8 mGy; QCA, 346.4 ± 387.8 mGy; P < .001) were also improved. The resampling rate was 16% and 21.8% for C-arm CT and QCA, respectively. The initial success rate of the performing radiologist remained stable during the study period (C-arm CT 75%; QCA, 82.1%, P = .259). Conclusions QCA might be superior to C-arm CT for improving the performance of AVS. Key Points • Adrenal venous sampling (AVS) is a technically challenging procedure. • C-arm CT and quick cortisol assay (QCA) are efficient for assisting AVS. • QCA might outperform C-arm CT in enhancing AVS performance.
Magnetic Resonance Imaging as a Diagnostic Tool for Ilio-Femoro-Caval Deep Venous Thrombosis
This study aimed to test the accuracy of a magnetic resonance imaging (MRI)-based method to detect and characterise deep venous thrombosis (DVT) in the ilio-femoro-caval veins. Patients with verified DVT in the lower extremities with extension of the thrombi to the iliac veins, who were suitable for catheter-based venous thrombolysis, were included in this study. Before the intervention, magnetic resonance venography (MRV) was performed, and the ilio-femoro-caval veins were independently evaluated for normal appearance, stenosis, and occlusion by two single-blinded observers. The same procedure was used to evaluate digital subtraction phlebography (DSP), considered to be the gold standard, which made it possible to compare the results. A total of 123 patients were included for MRV and DSP, resulting in 246 image sets to be analysed. In total, 496 segments were analysed for occlusion, stenosis, or normal appearance. The highest sensitivity compared occlusion with either normal or stenosis (0.98) in MRV, while the lowest was found between stenosis and normal (0.84). Specificity varied from 0.59 (stenosis >< occlusion) to 0.94 (occlusion >< normal). The Kappa statistic was calculated as a measure of inter-observer agreement. The kappa value for MRV was 0.91 and for DSP, 0.80. In conclusion, MRV represents a sensitive method to analyse DVT in the pelvis veins with advantages such as no radiation and contrast and the possibility to investigate the anatomical relationship in the area.
Venous Causes of Pulsatile Tinnitus: Clinical Presentation, Clinical and Radiographic Evaluation, Pathogenesis, and Endovascular Treatments: A Literature Review
Abstract Tinnitus is an abnormal perception of a sound without external stimulation. Venous pulsatile tinnitus (VPT) is a specific form of tinnitus characterized by an objective and often subjective bruit that occurs as a result of localized venous abnormalities. Clinical evaluation relies on sound quality, duration, and precipitating factors. Idiopathic intracranial hypertension (IIH) and transverse sinus stenosis (TSS) are among the most common causes of VPT. Other causes include sigmoid sinus wall abnormalities (SSWAs), jugular vein anomalies (JVAs), and emissary veins anomalies. These anomalies can be detected on magnetic resonance imaging, magnetic resonance angiography/magnetic resonance venography, and high-resolution temporal bone computed tomography. The pathogenesis behind the VPT includes turbulent blood flow as a result of luminal stenosis or abnormal dilation, amplification of internal sound due to temporal bone defects, and abnormal position of the venous sinus system structures adjacent to the bony structures of the auditive apparatus. Based on these theories, different interventional treatment modalities can be applied to treat the underlying causes. Endovascular treatments have shown high efficacy and safety among those treatments which include stenting of the lateral sinus stenosis in IIH and TSS, coiling of the SSWA and JVA, and embolization of emissary veins anomalies. Further studies are needed to understand the natural history of these anomalies and the efficacy of treatments of VPT, which—unlike other types of tinnitus—can be cured with proper treatment.
CT venography correlate of transverse sinus stenosis and venous transstenotic pressure gradient in unilateral pulsatile tinnitus patients with sigmoid sinus wall anomalies
Objectives To investigate the correlation between transverse sinus stenosis (TSS) and transstenotic pressure gradient (TPG) in unilateral pulsatile tinnitus (PT) patients with sigmoid sinus wall anomalies (SSWA). Methods Fifty-seven patients with unilateral venous PT were retrospectively included. All of them underwent CT venography and catheter manometry, accompanied with SSWA. The degree, length, shape (intrinsic/extrinsic/dysplasia), location (proximal/middle/distal, referring to the relative position of TSS and the Labbé vein junction) of TSS, the types of SSWA (dehiscence/diverticulum), and the degree of transverse sinus outflow laterality were assessed, and the correlations with ipsilesional TPG were analyzed. Results The mean value of ipsilesional TPG was 7.61 ± 0.52 mmHg. The degree and length of ipsilesional TSS were positively correlated with TPG ( p  < 0.001, p’  < 0.001), respectively. TPG was significantly larger in patients with contralateral transverse sinus dysplasia than those without ( p  = 0.023) and significantly smaller in patients with ipsilesional sigmoid sinus diverticulum than those with isolated dehiscence ( p  = 0.001). No statistical difference in TPG was shown between ipsilesional TSSs of different shapes or locations ( p  > 0.05). No correlation was noted between the degree of ipsilesional transverse sinus outflow laterality and TPG ( p  = 0.051). Stepwise linear regression indicated that the degree ( β  = 9.207, 95% CI = 3.558–14.856), length ( β  = 0.122, 95% CI = 0.025–0.220) of ipsilesional TSS, and contralateral transverse sinus dysplasia ( β  = 1.875, 95% CI = 0.220–3.530) were significantly correlated with TPG ( R 2  = 0.471). Conclusions The degree, length of ipsilesional TSS, and contralateral transverse sinus dysplasia may be used to predict TPG in unilateral PT patients with SSWA. Key Points • CT venography may act as a screening tool to help low-probability unilateral pulsatile tinnitus (PT) patients with sigmoid sinus wall anomalies (SSWA) avoid invasive catheter manometry. • The degree and length of ipsilesional transverse sinus stenosis (TSS) are positively correlated with transtenotic pressure gradient (TPG) in unilateral PT patients with SSWA. • Ipsilesional TPG is larger in unilateral PT patients with contralateral transverse sinus dysplasia than those without and is smaller in unilateral PT patients with sigmoid sinus diverticulum than those with isolated dehiscence.