The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Tsung O. Cheng - One of the best experts on this subject based on the ideXlab platform.
-
The last Swan song for the Swan-Ganz catheter?
International journal of cardiology, 2006Co-Authors: Tsung O. ChengAbstract:The in memoriam article about Jeremy Swan [1] coincided with the recent report by the National Heart, Lung, and Blood Institute Acute Respiratory Disease Syndrome (ARDS) Clinical Trials Network [2]. The latter may sound like the last nail on the coffin of the Swan–Ganz catheter. The controversy surrounding the benefits and risks of the use of the Swan–Ganz catheter is nothing new. It was merely a decade ago that a series of articles in JAMA [3,4] suggested that a moratorium be placed on its continued use. However, the editorial [5] accompanying the ARDS article has a more sobering tone: “It still has a role in diagnosis and in certain types of treatment, particularly the treatment of patients with suspected pulmonary arterial hypertension and right ventricular dysfunction [5]”. I also concur with Shure [5] that Swan–Ganz catheter may also have a role in patient populations not included in the NHLBI study [2], such as those with severe chronic obstructive pulmonary disease or with conditions requiring complex fluid management. As for a moratorium on the use of the Swan–Ganz catheter, only a bad workman blames his tools [6]. Perhaps it is not the Swan–Ganz catheter but the technique of placement or the treatment following its use that is at fault [6]. Furthermore, as Shure [5] said in her editorial, if an effective new therapeutic modality that requires information obtained only by the Swan–Ganz catheter emerges, the latter still will play an important role in management of such patients. Therefore, with the passing of
Jennifer Linn - One of the best experts on this subject based on the ideXlab platform.
-
susceptibility weighted angiography Swan of cerebral veins and arteries compared to tof mra
European Journal of Radiology, 2012Co-Authors: Tobias Boeckhbehrens, Juergen Lutz, T Wesemann, Veronika Schopf, N Lummel, Hartmut Bruckmann, Michael Burke, Jennifer LinnAbstract:Abstract Problem High resolution, non-contrast imaging of both cerebral veins and arteries by use of gradient echo T2 star weighted angiography (Swan) is a new method for susceptibility-weighted imaging with short acquisition times. We assessed the potential of this sequence for the depiction of both cerebral veins and arteries. Methods 15 healthy volunteers were included in the study. MRI was performed on a 3 T MR scanner using the following sequences: (1) a 3D multi-echo gradient echo T2 star weighted angiography (Swan), (2) an arterial 3D TOF MR angiography and (3) a venous 2D TOF. With regard to the Swan sequence, both MinIP and MIP images were reconstructed and systematically compared to MIP reconstructions of the artTOF and the venTOF. To suggest possible clinical implications of our findings, we additionally included two illustrative cases. Results With regard to the visualization of the cerebral veins, the MinIP reconstructions of the Swan sequence were considerably superior compared to the venTOF. Concerning the depiction of the main segments of the big cerebral arteries the value of the MIP reconstructions of the Swan was comparable to that of the artTOF with limitations in the homogenity and in the depiction of smaller arteries. Conclusions Swan allows for high-resolution visualization of both cerebral veins and arteries in one sequence without application of contrast agent and with significantly shortened scan time compared to the combined scan time of TOF-MRA and TOF-MRV. By use of either MinIP or MIP reconstructions, the arteries can be distinguished from the veins.
Rupert Grashey - One of the best experts on this subject based on the ideXlab platform.
-
susceptibility weighted angiography visualizes hypoxia in cerebral veins
Investigative Radiology, 2015Co-Authors: Maximilian Patzig, Berend Feddersen, Katrin Haegler, Jessica Freiherr, Rainald Fischer, Bernhard Olzowy, Ulrich Kisser, Sven Becker, Klaus Mees, Rupert GrasheyAbstract:OBJECTIVES: The objective of this study was to evaluate the influence of short- and long-term hypoxia on the depiction of cerebral veins in the susceptibility-weighted angiography (Swan) sequence. MATERIALS AND METHODS: In the context of a study on brain adaptation mechanisms to hypoxia, 16 healthy men (aged 20-28 years) were studied through magnetic resonance imaging (MRI) under room air conditions, short-term-hypoxia (7 minutes before and during the MRI scan), and long-term hypoxia (8.5 hours before and during the MRI scan). Oxygen saturation was continuously measured using a finger-mounted pulse oximeter. Two independent blinded readers compared the 3 scans of each participant and graded the Swan source images and minimum intensity projections according to the size, number, and signal intensity of the cerebral veins. Signal intensities of deep cerebral veins were measured, and signal intensity proportions of deep cerebral veins to different parenchymal brain regions were calculated. RESULTS: Nine subjects could be included in the study. In all of them, both readers correctly distinguished the 2 hypoxia scans from the baseline scan, grading the Swan images acquired under hypoxic conditions as visualizing cerebral veins more prominently. Signal intensities of the deep cerebral veins and signal intensity proportions were significantly lower in the hypoxia scans. No significant differences between short-term and long-term hypoxia were found on visual inspections and signal intensity measurements. This correlated with the results of the pulse oximetry: mean O2 saturation values were 97.9% ± 1.2% (baseline), 84.1% ± 3.8% (short-term hypoxia), and 82.8% ± 4.4% (long-term hypoxia), respectively. CONCLUSIONS: Hypoxia leads to visible and measurable changes in cerebral veins as depicted through Swan. Possible clinical implications of this finding include stroke and tumor imaging and need further investigation.
Jérôme Hodel - One of the best experts on this subject based on the ideXlab platform.
-
Comparison of 3D multi-echo gradient-echo and 2D T2* MR sequences for the detection of arterial thrombus in patients with acute stroke
European Radiology, 2014Co-Authors: Jérôme Hodel, Xavier Leclerc, Wassef Khaled, Ruben Tamazyan, Mathieu Rodallec, Sophie Gerber, Raphael Blanc, Mohamed Benadjaoud, Oriane Lambert, Cécile RabraitAbstract:Objectives We compared a multi-echo gradient-echo magnetic resonance sequence (susceptibility-weighted angiography [Swan]) with the T2* sequence for the detection of an arterial thrombus in acute ischaemic stroke. Methods Seventy-four consecutive patients with acute ischaemic stroke were included. Proximal arterial occlusions were diagnosed using time-of-flight (TOF) magnetic resonance angiography (MRA). Two-dimensional (2D) axial reformats from 3D Swan were generated to match with 2D T2* images. For arterial thrombus detection, each set of MR images (T2*, 2D Swan reformats and 3D multiplanar Swan images) was examined independently and separately by three observers who assigned the images to one of three categories: (0) absence of thrombus, (1) uncertain thrombus, (2) certain thrombus. Agreement and diagnostic accuracy were calculated. Results Twenty-four proximal arterial occlusions involving the anterior ( n = 20) or posterior ( n = 4) circulation were found. Inter-observer agreement was moderate using T2* images (κ = 0.58), good using 2D Swan reformats (κ = 0.83) and excellent using multiplanar Swan images (κ = 0.90). For the diagnosis of thrombus, T2* images were 54 % sensitive and 86 % specific, 2D Swan reformats were 83 % sensitive and 94 % specific and Swan multiplanar analysis was 96 % sensitive and 100 % specific. Conclusions Three-dimensional Swan sequence improves the detection of arterial thrombus in patients with acute ischaemic stroke in comparison with the 2D T2* sequence. Key Points • Multi - echo gradient - echo MR ( e.g. susceptibility - weighted angiograph , [ Swan ]) is increasingly used in neuroradiology . • Compared with conventional T2 * sequences , Swan improves detection of arterial thrombus . • Multiplanar Swan analysis had the best diagnostic performance for arterial thrombus detection . • Sensitivity was 96 % and specificity 100 %. • Findings support combination of time - of - flight and susceptibility effects in suspected acute stroke .
-
Susceptibility-weighted angiography for the detection of high-flow intracranial vascular lesions: preliminary study
European Radiology, 2013Co-Authors: Jérôme Hodel, Mathieu Rodallec, Sophie Gerber, Raphael Blanc, Cécile Rabrait, Antoine Guillonnet, Silvia Pistocchi, Rémi Sitta, Mathieu Zuber, Jean-pierre PruvoAbstract:Objectives Susceptibility-weighted magnetic resonance imaging (MRI) sequences may demonstrate various signal intensities of draining veins in cases of high-flow vascular malformation (HFVM), including arteriovenous malformation (AVM) and dural arteriovenous fistula (dAVF). Our objective was to evaluate susceptibility-weighted angiography (Swan) for the detection of HFVM. Methods Fifty-eight consecutive patients with a suspected intracranial vascular malformation were explored with Swan and post-contrast MRI sequences at 3 T. The diagnosis of slow-flow vascular malformation (SFVM), including developmental venous anomaly (DVA) or brain capillary telangiectasia (BCT), was based on MRI. Patients with suspected HFVM underwent digital subtraction angiography (DSA). Swan images were analysed by three blinded readers according to a three-point scale of the venous signal. Results Thirty-one patients presented 35 SFVM (26 DVA and 9 BCT) that systematically appeared hypointense on Swan images. In patients with atypical MRI findings, DSA revealed one patient with an atypical DVA and 26 patients with HFVM (22 AVM and 4 dAVF). Swan revealed at least one venous hyperintensity in all patients with HFVM. Agreement between readers was excellent. Conclusions Swan appears reliable for characterising blood flow dynamics in brain veins. In clinical practice, Swan can routinely rule out HFVM in patients with atypical brain veins. Key Points • Susceptibility - weighted angiography (Swan) offers new perspectives for detecting intracranial vascular malformations. • Swan sequence provides non - invasive characterisation of blood flow dynamics. • Swan can differentiate between high and slow flowing venous blood. • Swan can routinely rule out high - flow vascular malformations.
Jean-pierre Pruvo - One of the best experts on this subject based on the ideXlab platform.
-
Susceptibility-weighted angiography for the detection of high-flow intracranial vascular lesions: preliminary study
European Radiology, 2013Co-Authors: Jérôme Hodel, Mathieu Rodallec, Sophie Gerber, Raphael Blanc, Cécile Rabrait, Antoine Guillonnet, Silvia Pistocchi, Rémi Sitta, Mathieu Zuber, Jean-pierre PruvoAbstract:Objectives Susceptibility-weighted magnetic resonance imaging (MRI) sequences may demonstrate various signal intensities of draining veins in cases of high-flow vascular malformation (HFVM), including arteriovenous malformation (AVM) and dural arteriovenous fistula (dAVF). Our objective was to evaluate susceptibility-weighted angiography (Swan) for the detection of HFVM. Methods Fifty-eight consecutive patients with a suspected intracranial vascular malformation were explored with Swan and post-contrast MRI sequences at 3 T. The diagnosis of slow-flow vascular malformation (SFVM), including developmental venous anomaly (DVA) or brain capillary telangiectasia (BCT), was based on MRI. Patients with suspected HFVM underwent digital subtraction angiography (DSA). Swan images were analysed by three blinded readers according to a three-point scale of the venous signal. Results Thirty-one patients presented 35 SFVM (26 DVA and 9 BCT) that systematically appeared hypointense on Swan images. In patients with atypical MRI findings, DSA revealed one patient with an atypical DVA and 26 patients with HFVM (22 AVM and 4 dAVF). Swan revealed at least one venous hyperintensity in all patients with HFVM. Agreement between readers was excellent. Conclusions Swan appears reliable for characterising blood flow dynamics in brain veins. In clinical practice, Swan can routinely rule out HFVM in patients with atypical brain veins. Key Points • Susceptibility - weighted angiography (Swan) offers new perspectives for detecting intracranial vascular malformations. • Swan sequence provides non - invasive characterisation of blood flow dynamics. • Swan can differentiate between high and slow flowing venous blood. • Swan can routinely rule out high - flow vascular malformations.
