Syngo iFlow Research Articles

Feasibility study of Syngo iFlow in predicting hemodynamic improvement post-endovascular procedure in peripheral artery disease

ObjectiveThis study endeavors to examine the feasibility of predicting the clinical outcomes of patients suffering from peripheral artery disease (PAD) who undergo endovascular intervention, by employing the Syngo iFlow technology.MethodsRetrospectively enrolling 76 patients from December 2021 to May 2023, yielding a total of 77 affected limbs, this study employs clinical outcomes (improvement or otherwise) as the gold standard. Two physicians conducted visual assessments on both DSA and iFlow images to gauge patient improvement and assessed inter-observer consistency for each image modality. The Time to Peak (TTP) of regions of interest (ROI) at the femoral head, knee joint, and ankle joint was measured. Differences in pre- and post-procedure TTP were juxtaposed, and statistically significant parameter cutoff values were identified via ROC analysis. Employing these cutoffs for TTP classification, multivariate logistic regression and the C-statistic were utilized to assess the predictive value of distinct parameters for clinical success.ResultsEndovascular procedure exhibited technical and clinical success rates of 82.58 and 75.32%, respectively. Diagnostic performance of iFlow image visual assessment surpassed that of DSA images. Inter-observer agreement for iFlow and DSA image evaluations was equivalent (κ = 0.48 vs 0.50). Post-classification using cutoff values, multivariate logistic regression demonstrated the statistical significance of ankle joint TTP in post-procedure iFlow images of the endovascular procedure for clinical success evaluation (OR 7.21; 95% CI 1.68, 35.21; P = 0.010), with a C-statistic of 0.612.ConclusionSyngo iFlow color-encoded imagery holds practical value in assessing the technical success of post-endovascular procedures, offering comprehensive lower limb arterial perfusion visualization. Its quantifiable parameters exhibit promising potential for prognosticating clinical success.

Drawing time-density curve with Fiji/ImageJ: An alternative approach for parametric coding of cerebral digital subtraction angiography

BackgroundQuantitative spatiotemporal analysis of digital subtraction angiography could support clinical decision making for the management of cerebral vascular disease. However, there is a lack of free and user-friendly applications. The objective of our study is to devise a free and simple solution for parametric coding of digital subtraction angiography. New MethodBy driving the time-density curves in the region of interest, the digital subtraction angiography images were color-coded and quantitatively analyzed using fully open-source and free software (Fiji/ImageJ). The similarity factor (f2) was used to compare the resolution profiles between time-density curves generated with commercial software on the Siemens workstation (syngo iFlow, Siemens Healthcare, Berlin, Germany) and our method. Results and comparison with existing methodSixteen patients diagnosed with acute ischemic stroke resulting from acute occlusion of the distal internal carotid artery or the first segment of the middle cerebral artery were selected for analysis. Angiography images were successfully processed with syngo iFlow and Fiji/ImageJ. The images processed with Fiji/ImageJ provided excellent anatomic and hemodynamic details. In all patients, the similarity factor (f2) values of the time-density curves derived from the same region of interest were 99.90 (range 99.85–99.95). ConclusionsThe ImageJ/Fiji software provides a user-friendly and free alternative for parametric coding of digital subtraction angiography.

Evaluation of ocular blood flow in the assessment of symptomatic carotid stenosis.

The degree of internal carotid artery (ICA) stenosis determined by criteria from the North American Symptomatic Carotid Endarterectomy Trial (NASCET) is not the most accurate index to assess distal flow compromise. Distal ICA perfusion is also determined by factors such as tandem carotid stenosis and collateral circulation. Quantification of end-organ ocular perfusion using non-invasive laser speckle flowgraphy (LSFG) may provide insights into distal ICA flow. This study prospectively assessed the degree of ICA flow using LSFG. Eighteen patients with symptomatic carotid stenosis underwent LSFG evaluation. LSFG was used to extract ocular blood flow metrics recorded simultaneously in the retina, choroid, and optic nerve head. The following ocular flow parameters were measured with LSFG: mean blur rate (MBR), flow acceleration index (FAI), and rising rate (RR). Syngo iFlow perfusion imaging was used to objectively quantify contrast flow in the ICA and brain parenchyma during digital subtraction angiography. Time to peak (TTP) and contrast delay were extracted from seven different regions of interest (ROIs). MBR, FAI, and RR were correlated with NASCET degree of stenosis. FAI and RR also improved after stenting. TTP improved after stenting in three ROIs. A moderate negative correlation was observed between FAI and contrast delay. LSFG non-invasively quantifies end-organ blood flow distal to the ICA origin. LSFG metrics have the potential to quantify end-organ perfusion and determine if a proximal carotid stenosis is symptomatic.

Effect of prolonged microcirculation time after thrombectomy on the outcome of acute stroke

BackgroundAlthough recanalization can be successful, microcirculatory dysfunction is common in acute large vessel occlusive stroke (LVOS). We assessed the microcirculation time by postprocessing software and analyzed its impact on prognosis...

Treatment of Wide-Necked Cerebral Aneurysms Using the WEB Device Including Flow Alteration Assessment With Color-Coded Imaging: A Single Center Experience

The Woven EndoBridge (WEB) device (MicroVention, Tustin, CA) has extended the treatment of cerebral aneurysms. Despite the fact that the WEB device has shown promising clinical results, little is known about the caused intra-aneurysmal flow alterations. Here we present our clinical experience with the WEB, including examining various syngo iFlow (Siemens AG, Erlangen, Germany) parameters to predict aneurysm occlusion. We reviewed the data from patients with unruptured cerebral aneurysms treated with a WEB device between 2016 and 2020. Aneurysm occlusion and complications were assessed. Furthermore, different quantitative criteria were evaluated using syngo iFlow after digital subtraction angiography. A total of 26 patients hosting 26 cerebral aneurysms met the inclusion criteria. Follow-up was available for 21 patients, with a mean of 7.3 ± 6.3 months. A total of 71.4% (n= 15) of the aneurysms included were located in the anterior and 28.6% (n= 6) in the posterior circulation. Adequate aneurysm occlusion was achieved in 85.7% (n= 18). The iFlow parameters for reduced aneurysm outflow (ID-R) differed significantly from the parameters for reduced inflow (PI-R and PI-D) (P < 0.001). The parameters did not differ significantly between adequately and insufficiently occluded aneurysms. Only a trend towards a lower ID-R of insufficiently occluded aneurysms was observed (P= 0.063), indicating a potential predictive value for insufficient aneurysmal outflow. There was no treatment-related morbidity or mortality. The applied syngo iFlow parameters confirmed that flow changes induced by the WEB device significantly affect outflow compared to inflow and have potential predictive value for adequate aneurysm occlusion.

Evaluation of Tissue Perfusion by Wound Blush and 2D Color-Coded Digital Subtraction Angiography During Endovascular Intervention and Its Impact on Limb Salvage in Critical Limb Ischemia

Purpose: Critical limb ischemia (CLI) is an entity with high mortality if not properly treated. The primary aim of CLI revascularization is to enhance wound healing, which greatly depends on microvascular circulation. The available tools for assessment of revascularization success are deficient in the evaluation of local microvascular tissue perfusion, that wound blush (WB) reflects. A reliable technique that assesses capillary flow to foot lesions is needed. This study aims to assess WB angiographically at sites of interest in the foot after revascularization and its impact on limb salvage in CLI. Materials and Methods: 198 CLI patients (Rutherford category 5/6) with infrainguinal atherosclerotic lesions amenable for endovascular revascularization (EVR) were included. Limbs were directly or indirectly revascularized by EVR. Direct revascularization meant that successful revascularization of the area of interest according to the angiosome concept was achieved. A completion angiographic run was taken to assess WB. Patients were divided into 2 groups; positive and negative WB groups. In the event of a disagreement between the observational investigators, the digital subtraction angiography (DSA) series was analyzed for hemodynamic changes with a computerized 2D color-coded DSA (Syngo iFlow). Results: 176 limbs had successful revascularization in 157 patients. The successful revascularization rate was 88.9% (176/198), with technical failure encountered in 22 limbs. 121 patients had positive WB and 55 patients had negative WB. Direct revascularization of target areas was obtained in 98 limbs (55.7%). There was a significant difference in the rate of achieving direct flow to the lesion between the positive WB and negative WB groups (36.4% vs 19.3%, p≤0.001). We noticed a nonsignificant difference between patients who had direct revascularization of the foot lesion(s) and those who had indirect revascularization as regards limb salvage. Patients were followed up for 25.2 ± 12.7 months. By the end of the first year, limb salvage rate was significantly higher in patients who had positive WB (98% vs 63%, p<0.001, after 2 years (97% vs 58%, p<0.001) and after 3 years (94% vs 51.5%, p<0.001). Conclusions: WB is an important predictor and a prognostic factor for wound healing in CLI patients with soft tissue lesions.

Quantitative analysis of renal blood flow during thoracic endovascular aortic repair in type B aortic dissection using syngo iFlow.

Currently, the thoracic endovascular aortic repair is the recommended clinical treatment for type B aortic dissections. Unfortunately, malperfusion or ischemia of the kidneys is a major complication of type B aortic dissections. Despite this, few studies have focused on the effects of thoracic endovascular aortic repair on blood flow in renal arteries and parenchyma. This current investigation used novel real-time imaging software to quantitatively analyze the hemodynamic changes in renal artery blood flow and perfusion before and after stent graft placement. A total of 51 patients with type B aortic dissection undergoing thoracic endovascular aortic repair between April 2017 and September 2019 were retrospectively recruited. The pre-and post-procedural digital subtraction angiography images were converted into color-coded maps using syngo iFlow for quantitative comparison. Time-intensity curves and related parameters, including the average peak ratio (avg.Pr), average delayed time to peak (avg.dTTP), and average area under the curve ratio (avg.AUCr) of the renal arteries and renal cortex were obtained and analyzed. Wilcoxon signed-rank test was used to compare iFlow parameters before and after endovascular repair. Spearman correlation analyses were performed to study iFlow parameters and renal function parameters and the estimated glomerular filtration rate (eGFR) and blood urea nitrogen (BUN). A total of 102 images including 51 pre-operative and 51 post-operative image datasets were successfully post-processed. Following endovascular repair, syngo iFlow showed a significant 33.0% increase in avg.Pr (P<0.001) and a significant 35.1% increase in avg.AUCr (P<0.001) in the renal artery. Additionally, there was a significant 12.2% decrease in the avg.dTTP (P=0.001), a significant 24.5% increase in avg.Pr (P=0.004), and a significant 38.3% increase in avg.AUCr (P=0.009) in the renal cortex. Spearman correlation analysis showed that after endovascular repair there was a significant correlation between the avg.Pr of the renal artery and eGFR (r=0.30; P=0.0349), the avg.Pr of the renal cortex and eGFR (r=0.30; P=0.0300), and the avg. AUCr of the renal cortex and BUN (r=0.31; P=0.0289). syngo iFlow provided a novel quantitative method for evaluating renal hemodynamic changes in patients with type B aortic dissection undergoing endovascular treatment. Time-intensity curve parameters may facilitate the intraprocedural evaluation of renal blood flow and perfusion to complement the color-coded map.

Retrospective analysis of intracranial aneurysms after flow diverter treatment including color-coded imaging (syngo iFlow) as a predictor of aneurysm occlusion.

Flow Diverters (FD) have immensely extended the treatment of cerebral aneurysms in the past years. Complete aneurysm occlusion is a process that often takes a certain amount of time and is usually difficult to predict. Our aim was to investigate different syngo iFlow parameters in order to predict aneurysm occlusion. Between 2014 and 2018 patients with unruptured cerebral aneurysms treated with a FD were reviewed. Aneurysm occlusion and complication rates have been assessed.In addition, various quantitative criteria were assessed using syngo iFlow before, after the intervention, and after short and long-term digital subtraction angiography (DSA). A total of 66 patients hosting 66 cerebral aneurysms were included in this study. 87.9% (n = 58) aneurysms in the anterior and 12.1% (n = 8) in the posterior circulation were treated. Adequate aneurysm occlusion at long-term follow-up (19.05 ± 15.1 months) was achieved in 90.9% (n = 60). Adequately occluded aneurysm revealed a significantly greater peak intensity delay (PI-D, p = 0.008) and intensity decrease ratio (ID-R, p < 0.001) compared to insufficiently occluded aneurysms. Increased intra-aneurysmal contrast agent intensity (>100%) after FD implantation resulted in an ID-R < 1, which was associated with aneurysm growth during follow-up DSA. Retreatment with another FD due to foreshortening and/or aneurysm growth was performed in 10.6% (n = 7). Overall morbidity and mortality rates were 1.5% (n = 1) and 0%. The applied syngo iFlow parameters were found to be useful in predicting adequate aneurysm occlusion and foresee aneurysm growth, which might indicate the implantation of another FD.

Association of intracranial arteriovenous malformation embolization with more rapid rate of perfusion in the peri-nidal region on color-coded quantitative digital subtraction angiography

BackgroundHemodynamic alterations post-embolization of intracranial arteriovenous malformations (AVMs) may cause delayed edema/hemorrhage in brain parenchyma adjacent to the lesion.ObjectiveTo quantify and compare cerebral perfusion changes in the peri-AVM territory pre-...

Verification of the usefulness of 3D syngo iFlow in cerebrovascular blood flow analysis

Verification of the usefulness of 3D syngo iFlow in cerebrovascular blood flow analysis

Parametric Color Coding of Digital Subtraction Angiography in the Evaluation of the Type B Chronic Aortic Dissection During Tevar: A Preliminary Study

Introduction - Angiografic assessment of type B chronic aortic dissection (TBCAD) can be complex in TEVAR procedures, due to the presence of true and false lumen. Quantitative digital subtraction angiography (Q-DSA) with a parametric color-coding provides a novel approach for encoding temporal information and enabling quantitative measurements. (1,2) The potential value of the use of color in the display of these parametric images was recognized (3), particularly useful in situations in which there is a complex flow pattern. (4,5) The aim of this study was to evaluate whether the use of parametric color-coding in the post processing of DSA series is advantageous in the evaluation of TBCAD during TEVAR procedures. Methods - We enrolled 11 patients treated electively for a TBCAD. All cases were treated with TEVAR for a aneurysm disease of thoracic descending aorta (> 6 cm) with the coverture of proximal entry tear. For postprocessing of digital subtraction angiography (DSA) series, a newly implemented algorithm of parametric color-coding was used, turning sequential images of two-dimensional (2D)-DSA series into a single color-coded image (Syngo I-Flow, Siemens AG, Forchheim, Germany). In consensus reading, two experienced vascular surgeons valuated the initial, interventional, and post-interventional 2D-DSA series comparing them to the color-coded images, respectively. Whether parametric color-coding could facilitate evaluation of a true and false lumen and provide a more precise estimation of proximal entry tear as well as whether flow analysis could reveal objective changes during and after TEVAR treatment were investigated. Results - In 81.8 % of the cases, parametric color coding was observed to facilitate visualization of the aortic dissection angioarchitecture in term of true e false lumen contemporary vision. Estimation of proximal entry tear was considered to be improved in 45.4 % of the cases (fig. 1. maximum intensity peak DSA (a) and parametric color elaboration with entry tear enhanced (b)). For assessment of hemodynamic changes during and after treatment, parametric color coding was assumed to be helpful in 36.3 % of the cases, especially because revealing flow changes that were not visible on 2D-DSA series were now visible. Conclusion - Without additional cost in term of x-ray and contrast medium exposure, parametric color-coding is a real time application tool that might provide additional support in the angiographic evaluation of TBCAD during TEVAR. Visualization of complex aortic dissection architecture could be facilitated, and flow analysis might improve assessment of entry tear position, thereby increasing overall diagnostic confidence. During and after treatment, hemodynamic changes that were not visible on 2D-DSA series could now be depicted.

Abstract WP26: Factors Related to Acute Brain Swelling After Successful Recanalization With Mechanical Thrombectomy

Background and Purpose: We have experienced acute ischemic stroke patients who had poor outcome due to acute brain swelling after successful recanalization with mechanical thrombectomy. The aim of this study was to investigate factors related to acute brain swelling. Methods: The study included 89 patients who obtained successful recanalization (TICI 2b or 3) after mechanical thrombectomy for occlusions of the internal carotid artery (ICA) or middle cerebral artery from 2013 to June 2016. We classified by the distance of midline shift on FLAIR image including the lens nucleus and thalamus within 24 hours after treatment into 2 groups; more than 5 mm (Swelling group; the S group, n=16), and less than 5 mm (Non-Swelling; the N group, n=73). We compared demographic data, radiological characteristics, and outcomes between both groups. We also measured flow transit time (FTT) from intracranial artery to cortical vein with the use of automated software (syngo iflow, Siemens Healthcare, Germany). Results: Regarding mean time of onset-to-reperfusion time, medical history, treatment with IV-rtPA, there were no significant differences between both groups. Increase rate of the brain swelling area before and after treatment on FLAIR image was higher in the S group (20.9%) than in the N group (3.0%). The median FTT of the S group was 7.0 sec (IQR 4.5-7.5), the N group was 6.0 sec (5.2-6.5). The S group included more patients of ICA occlusion (80% vs. 46%, p=0.023), longer FTT (&gt;7.0 sec, 60% vs. 13%, p&lt;0.001), and lower DWI-ASPECTS (median 3 vs. 7, p&lt;0.001). Parenchymal hematoma was equivalent in each group. Modified Rankin Scale score 0-2 at 90 days was significantly lower in the S group (0% vs. 37%, p=0.004). Logistic regression analysis showed FTT of more than 7 seconds was a significant independent predictor [OR 9.77 (2.13-54), p=0.003] of acute brain swelling. Conclusion: Important factors related to acute brain swelling after successful thrombectomy were ICA occlusion, lower DWI-ASPECTS, and longer FTT. Particularly FTT was a significant independent predictor of acute brain swelling.

Reductions in brain pericytes are associated with arteriovenous malformation vascular instability.

OBJECTIVEBrain arteriovenous malformations (bAVMs) are rupture-prone tangles of blood vessels with direct shunting of blood flow between arterial and venous circulations. The molecular and/or cellular mechanisms contributing to bAVM pathogenesis and/or destabilization in sporadic lesions have remained elusive. Initial insights into AVM formation have been gained through models of genetic AVM syndromes. And while many studies have focused on endothelial cells, the contributions of other vascular cell types have yet to be systematically studied. Pericytes are multifunctional mural cells that regulate brain angiogenesis, blood-brain barrier integrity, and vascular stability. Here, the authors analyze the abundance of brain pericytes and their association with vascular changes in sporadic human AVMs.METHODSTissues from bAVMs and from temporal lobe specimens from patients with medically intractable epilepsy (nonvascular lesion controls [NVLCs]) were resected. Immunofluorescent staining with confocal microscopy was performed to quantify pericytes (platelet-derived growth factor receptor-beta [PDGFRβ] and aminopeptidase N [CD13]) and extravascular hemoglobin. Iron-positive hemosiderin deposits were quantified with Prussian blue staining. Syngo iFlow post-image processing was used to measure nidal blood flow on preintervention angiograms.RESULTSQuantitative immunofluorescent analysis demonstrated a 68% reduction in the vascular pericyte number in bAVMs compared with the number in NVLCs (p < 0.01). Additional analysis demonstrated 52% and 50% reductions in the vascular surface area covered by CD13- and PDGFRβ-positive pericyte cell processes, respectively, in bAVMs (p < 0.01). Reductions in pericyte coverage were statistically significantly greater in bAVMs with prior rupture (p < 0.05). Unruptured bAVMs had increased microhemorrhage, as evidenced by a 15.5-fold increase in extravascular hemoglobin compared with levels in NVLCs (p < 0.01). Within unruptured bAVM specimens, extravascular hemoglobin correlated negatively with pericyte coverage (CD13: r = -0.93, p < 0.01; PDGFRβ: r = -0.87, p < 0.01). A similar negative correlation was observed with pericyte coverage and Prussian blue-positive hemosiderin deposits (CD13: r = -0.90, p < 0.01; PDGFRβ: r = -0.86, p < 0.01). Pericyte coverage positively correlated with the mean transit time of blood flow or the time that circulating blood spends within the bAVM nidus (CD13: r = 0.60, p < 0.05; PDGFRβ: r = 0.63, p < 0.05). A greater reduction in pericyte coverage is therefore associated with a reduced mean transit time or faster rate of blood flow through the bAVM nidus. No correlations were observed with time to peak flow within feeding arteries or draining veins.CONCLUSIONSBrain pericyte number and coverage are reduced in sporadic bAVMs and are lowest in cases with prior rupture. In unruptured bAVMs, pericyte reductions correlate with the severity of microhemorrhage. A loss of pericytes also correlates with a faster rate of blood flow through the bAVM nidus. This suggests that pericytes are associated with and may contribute to vascular fragility and hemodynamic changes in bAVMs. Future studies in animal models are needed to better characterize the role of pericytes in AVM pathogenesis.

The potential role of quantitative digital subtraction angiography in evaluating type B chronic aortic dissection during TEVAR: preliminary results.

To evaluate the role of quantitative digital subtraction angiography (Q-DSA) with parametric color coding (PCC) in assessing patients with type B chronic thoracic aortic dissection (TBCAD) during thoracic endovascular aortic repair (TEVAR) procedures. A total of 11 patients electively treated in our Department for a TBCAD were retrospectively enrolled. All cases were treated with TEVAR for false lumen aneurysm of the thoracic descending aorta. For digital subtraction angiography (DSA) series post-processing, a newly implemented PCC algorithm was used to turn consecutive two-dimensional images into a single color-coded picture (syngo iFLOW, Siemens AG, Forchheim, Germany). In consensus reading, two clinicians experienced in vascular imaging evaluated the DSA series in blinded assessment and compared them to the color-coded images. PCC was assessed for its accuracy in identifying the true and false lumen as well as whether it could provide improved visualization in pre-deployment stent grafting and the final evaluation of treatment. PCC facilitated the visualization of the aortic dissection angioarchitecture in terms of contemporary true and false lumen vision in 81.8% of the cases. In 72.7% of the procedures, Q-DSA was estimated to improve aorta information assessment in terms of false lumen viewing, and it was possible to identify the proximal entry tear position in 45.4% of the cases. After stent graft deployment, in 72.7% of the cases (all 8 patients in which the aortic arch false lumen was visible in pre-treatment), Q-DSA confirmed the absence of early false lumen reperfusion. Our results indicate that Q-DSA could be useful in the intraprocedural evaluation of patients with aortic dissection during TEVAR procedures without additional x-ray costs and contrast exposure.

Intracranial contrast transit times on digital subtraction angiography decrease more in patients with delayed intraparenchymal hemorrhage after Pipeline

Background Pipeline embolization devices (PEDs) are used for endovascular treatment of cerebral aneurysms but can be associated with delayed ipsilateral intraparenchymal hemorrhage (DIPH). Changes in intracranial hemodynamics after PED are poorly understood. Objective Here, we assess hemodynamic changes after PED in patients and compare these changes in patients with and without DIPH (DIPH+ and DIPH-). Methods Records of patients with distal internal carotid artery (ICA) aneurysms treated with PED at our institution between 2012 and 2017 were retrospectively reviewed. Regions of interest were selected proximally to PED over the cavernous ICA and distally over the middle cerebral artery (MCA), and then transit times were determined using syngo iFlow software (Siemens). Ratio of MCA to ICA transit time was compared before, after treatment, and at follow-up. Ratios were also compared between DIPH+ and DIPH- subgroups. Correlations between aneurysm size, age, and ratios were investigated. Results Fifty-three patients were included. The ratio of MCA to ICA transit time decreased significantly after PED deployment (1.13 vs. 1.22, p < 0.01). The ratio in the DIPH + subgroup ( n = 4) was significantly lower (1.00 vs. 1.14, p = 0.01) and decreased significantly more (21% vs. 4.4%, p = 0.02) compared to the DIPH- subgroup ( n = 49). The ratio tended to be higher in larger aneurysms at baseline ( r = 0.25, p = 0.07) but not after PED treatment ( r = 0.11, p = 0.15). Age did not correlate with ratio. Conclusion The ratio of MCA to ICA transit time decreases following PED treatment and decreases more in patients with DIPH. These contrast transit time changes can be detected in real time immediately after PED deployment.

In vitro, contrast agent-based evaluation of the influence of flow diverter size and position on intra-aneurysmal flow dynamics using syngo iFlow.

Treatment of intracranial aneurysm with flow-diverting devices has become widespread in recent years. Despite that, intra-aneurysmal flow changes are yet not fully understood and can lead to different complications. Our aim was an in vitro contrast-based evaluation of the influence of flow diverter size and position on intra-aneurysmal flow dynamics. Flow-diverting devices with different sizes (diameters 4.0, 4.5, and 6.0mm) were deployed in seven silicone aneurysm models at different positions relative to the aneurysm neck (proximal, central, distal). Using syngo iFlow, we defined quantitative evaluation criteria based on contrast medium intensity and performed a flow evaluation. Intra-aneurysmal flows were heavily dependent on both size and position of flow-diverting devices at the aneurysm neck. We observed a higher peak intensity delay and intra-aneurysmal washout delay with the centrally placed 4.0- and 4.5-mm device, respectively, compared to the proximal and distal positions. Especially distally placed 4.0-mm devices led to an earlier filling of the aneurysm and increased intra-aneurysmal contrast agent intensity compared to the parent vessel, due to a potential endoleak. Not only size but also position of flow-diverting devices have a considerable impact on the intra-aneurysmal flow dynamics. The suggested evaluation criteria allowed a quantitative comparison of flow-diverting effect using syngo iFlow and could represent an efficient tool for predicting flow diversion pre-procedurally.

Delayed Venous Drainage in Ruptured Arteriovenous Malformations Based on Quantitative Color-Coded Digital Subtraction Angiography

Clinically applicable hemodynamic risk factors to predict arteriovenous malformation (AVM) rupture are missing in the literature. The aim of this study was to use catheter angiography to identify hemodynamic parameters in ruptured and unruptured AVMs. Patients with frontal and temporal AVMs and Siemens syngo iFlow color-coding angiography were included in this study (n= 71). Clinical and radiologic data (age, sex, Spetzler-Martin [SM] and supplemented SM grade, and rupture status), and hemodynamic features (contrast mean transit time [MTT] of feeding arteries, draining veins, AVM nidus, and the cerebral circulation time [CCT]) were analyzed. Univariable analysis was performed to compare findings between ruptured and unruptured AVMs. In total, 35 ruptured and 36 unruptured AVMs were analyzed. Clinical characteristics and AVM grades were comparable between ruptured and unruptured AVMs. Ipsilateral CCT (5.2 vs. 4.0 seconds; P= 0.035), MTT between Tmax of the ipsilateral internal carotid artery and Tmax of sinus entry of the draining vein (3.2 vs. 2.0 seconds; P < 0.001), and MTT between Tmax at the start of venous outflow and Tmax of sinus entry (1.6 vs. 0.7 seconds; P<0.0001) were significantly longer in ruptured compared with unruptured AVMs. MTTs of nidus, between the internal carotid and feeding arteries, of the venous sinus passage as well as contralateral CCT and controlled ipsilateral CCT were comparable between both groups. Ruptured AVMs have significantly prolonged venous drainage times compared with unruptured AVMs; this suggests restricted AVM drainage and increased blood pressure within the AVM nidus. Prospective studies are needed to determine the predictive power of these measurements.

Validation of cerebral arteriovenous malformation hemodynamics assessed by DSA using quantitative magnetic resonance angiography: preliminary study

BackgroundThe hemodynamic evaluation of cerebral arteriovenous malformations (AVMs) using DSA has not been validated against true flow measurements.ObjectiveTo validate AVM hemodynamics assessed by DSA using quantitative magnetic resonance angiography (QMRA).Materials...

Novel Software-Assisted Hemodynamic Evaluation of Pelvic Flow During Chemoperfusion of Pelvic Arteries for Bladder Cancer: Double- Versus Single-Balloon Technique.

PurposeApproximately 83 % of patients with bladder cancer have achieved a complete response after undergoing a novel bladder preservation therapy involving balloon-occluded intra-arterial infusion chemotherapy (BOAI) using a four-lumen double-balloon catheter, known as the Osaka Medical College regimen. This study aimed to show the quantitative difference in hemodynamics of the bladder arteries using syngo iFlow (Siemens Healthcare, Erlangen, Germany), which provides an automatic tool for quantitative blood flow analysis between double BOAI (D-BOAI) and conventional single BOAI (S-BOAI).Materials and MethodsFifty patients were included. The catheters were introduced into both posterior trunks of the internal iliac arteries via contralateral femoral artery access. A side hole between the distal and proximal balloons was placed at the origin of each bladder artery to allow clear visualization of angiographic flow of the injected agent into the urinary bladder. Digital subtraction angiography was used during analysis with the syngo iFlow to evaluate the hemodynamics of the contrast medium in the pelvic arteries during BOAI. The comparative change in the amount of contrast medium in the bladder arteries between D-BOAI and S-BOAI was assessed using syngo iFlow.ResultsOne-hundred pelvic sides were analyzed. The amount of contrast medium in the bladder arteries using D-BOAI was more than twice that using S-BOAI (right, 3.03-fold; left, 2.81-fold).ConclusionThe amount of contrast medium in the bladder arteries using D-BOAI was higher than that using conventional S-BOAI. This may increase the anticancer drug concentration in the affected bladder, leading to a good clinical response.

Clinical values of hemodynamics assessment by parametric color coding of digital subtraction angiography before and after endovascular therapy for critical limb ischaemia

To investigate the feasibility of parametric color coding of digital subtraction angiography (Syngo iFlow) for hemodynamics assessment in patients with critical limb ischemia in pre- and post-endovascular therapy. To explore the correlation between Syngo iFlow and the conventional techniques. from January 2013 to December 2014, Clinical data of 21 patients with TASC II type B and type C femoropopliteal arteriosclerotic occlusive disease who were treated by percutaneous transluminal angioplasty and/or primary stent implantation in Nanjing first hospital were analyzed retrospectively. Of these patients there were 10 males and 11 females with an average age of (72±6) years (range from 58-85 years). The treatment efficacy was assessed by the variation of a series of clinical symptoms indexes (such as pain score, cold sensation score and intermittent claudication score), ankle braehial index (ABI) and transcutaneous oxygen pressure (TcPO2). Angiography was performed with the same protocol before and after treatment and parametric color coding of digital subtraction angiography was created by Syngo iFlow software on a dedicated workstation. The time to peak (TTP) of artery and tissue perfusion selected at the same regions of foot and ankle were measured and analyzed to evaluate the improvement of microcirculation and hemodynamics of the ischemic limb. The correlations between Syngo iFlow and the traditional clinical evaluation methods were explored using the Spearman rank correlation test. All patients (21 limbs) underwent successful endovaseular therapy. The mean pain score, cold sensation score, intermittent claudication score, ABI and TcPO2 before treatment were (0.48±0.68), (2.71±0.72), (2.86±0.85), ABI (0.33±0.07), TcPO2 (26.83±3.41) mmHg. While 1 week after treatment all above indicators were (2.57±0.93), (0.33±0.48), (0.90±0.54), (0.69±0.11), TcPO2 (53.75±3.60) mmHg respectively. There were significant statistical differences between pre- and post-treatment (P<0.05). The pre- and post-operative TTP of artery and tissue perfusion were (14.07±1.77) vs (10.43±2.05) s, (18.75±2.72) vs (15.38±2.78) s. For assessment of hemodynamic changes during and after treatment, parametric color coding of digital subtraction angiography (Syngo iFlow) was assumed to show the limb blood flow and perfusion were improved and the differences were statistically significant. The Spearman rank correlation test showed the TTP of artery was positively correlated with ABI, TcPO2 (r=0.65, 0.73, P<0.05), the TTP of tissue perfusion was also positively correlated with ABI, TcPO2 (r=0.60, 0.60, P<0.05). Parametric color coding of digital subtraction angiography (Syngo iFlow) is a real-time, sensitive and quantitative tool that might provide additional support in the hemodynamics evaluation of endovascular treatment for patients with lower extremity peripheral arterial occlusion disease.