Vascular Diagnostic and Surgical Treatments Before Lower Limb Amputations in Patients with Arterial Vascular Diseases: A Population Based Study from 2013 to 2015 in Germany.

OBJECTIVE: Patients with peripheral artery disease (PAD) have an increased risk of lower limb amputation. Given the international wide variance in major amputations, the high mortality rates and follow up costs as well as the significantly reduced quality of life of patients with amputations, vascular diagnostics and vascular surgery treatments are of great importance for lower limb preservation in patients with PAD. This study examines these guideline based procedures in patients before a first lower limb amputation and PAD. METHODS: This was a retrospective longitudinal study. Data from a large German statutory health insurance scheme were examined on patients with first amputation of lower extremities and PAD between 2013 and 2015 (incidence). Pre-defined vascular diagnostic and vascular surgical procedures were considered, as specified by guidelines within inpatient and outpatient care in a defined time before lower limb amputation. RESULTS: The overall estimated incidence of lower extremity amputations in the total population was 0.12% from 2013 to 2015. Of these, 51.7% had PAD; 81.8% of patients received at least one vascular diagnostic measure and 61.0% a vascular surgery procedure before the lower extremity amputation. There were only minor variations in the use of diagnostic or surgical treatments between patients with major and minor amputation. In total, 63.9% of patients had vascular surgery before the incident major amputation compared with 60.0% of patients with a minor amputation. Noticeable regional differences were found ranging from 91% (Berlin) to 67% (Bremen) regarding diagnostic procedures provided before amputation, and from 83% (Hamburg) to 55% (Saxony-Anhalt) regarding vascular surgery before amputations. CONCLUSION: Of patients with PAD, 18.2% did not receive a vascular diagnostic examination before amputation as specified in the guidelines, which reflects an underuse of health services. In one third of patients who did not receive vascular surgery, major amputation probably could have been avoided.

Use of Head and Neck Magnetic Resonance Angiography to Explore Neurological Function Recovery and Impact of Rehabilitation Nursing on Patients with Acute Stroke.

OBJECTIVE: To analyze neurological function recovery and the impact of rehabilitation nursing in patients with cerebral stroke after treatment to aid clinical diagnosis and treatment of cerebral stroke. METHODS: The study comprised 140 patients who were hospitalized in the neurology department for magnetic resonance angiography examination. Patients were divided into a treatment group (70 patients) and a control group (70 patients) based on treatment plan. Digital subtraction angiography was regarded as the gold standard diagnostic examination. In patients in both groups, magnetic resonance angiography features of the M1 segment of the middle cerebral artery and diagnostic specificity and sensitivity were recorded. An activities of daily living score was used to assess neurological function of patients before and after rehabilitation. RESULTS: The activities of daily living scores of patients in both groups increased significantly after treatment (P < 0.05); the scores of patients in the treatment group increased more significantly (P < 0.05). The total effective rate was 89% in the treatment group and 60% in the control group. The difference between the 2 groups was statistically significant (P < 0.05). After treatment, the degree of M1 segment stenosis in both groups was better than before treatment, and the number of collateral circulation branches was increased; the improvements in the treatment group were more significant (P < 0.05). CONCLUSIONS: Rehabilitation nursing could greatly improve the stenosis of blood vessels in patients with acute cerebral stroke and promote the establishment of collateral circulation, thereby effectively enhancing the recovery of neurological function and strengthening the ability of patients to perform activities of daily living.

Correlation between CT angiography and digital subtraction angiography in acute ischemic strokes.

OBJECTIVE: CT angiography (CTA) is not necessarily performed for all acute ischemic strokes due to variations in national guidelines across different regions. It follows that in the absence of CTA, missed identification of large vessel occlusion (LVO) potentially leads to opportunity lost for endovascular thrombectomy. Although the accuracy of CTA is well validated in chronic arterial stenosis, it has not been adequately investigated in acute ischemic stroke. We aimed to investigate the accuracy of CTA compared with digital subtraction angiography (DSA) in detecting LVO in acute ischemic stroke. METHODS: This was a retrospective study of acute ischemic strokes with large vessel occlusion which underwent endovascular thrombectomy. We included patients who had a CTA prior to DSA and did not receive intravenous thrombolysis. Images were reviewed by 2 blinded assessors. Positive predictive value (PPV), and negative predictive value (NPV) of CTA were calculated against DSA. RESULTS: Seventy-seven patients were included. The median age was 67 (IQR 57-78) and 46 (59.7 %) were male. Median NIHSS was 18 (IQR 12-22). There were 284 arterial segments categorized into 215 anterior arterial segments in 54 patients and 69 posterior arterial segments in 23 patients. The median time between CTA and DSA was 126 min (IQR 91-153 min). CTA showed PPV of 91.1 % and NPV of 95.1 % compared with DSA. CONCLUSIONS: We showed that CTA was reasonably accurate in identifying large vessel occlusion in acute ischemic stroke. We propose that current regional guidelines should include CTA for all acute ischemic strokes.

A systematic review of non-trunk basilar perforator aneurysms: is it worth chasing the small fish?

BACKGROUND AND PURPOSE: Non-trunk basilar artery perforator aneurysms (BAPAs) are rare intracranial vascular pathologies that have long been underdiagnosed, under-reported, and under-analyzed. We performed a systematic review of the efficacy and safety endpoints between conservative and active treatment approaches for non-trunk BAPAs. METHODS: Major databases were analyzed for relevant publications between 1995 and 2019. Studies comparing the outcomes between conservative and active treatment approaches such as coiling, stenting, clipping, liquid embolization, and flow diversion were included. Mortality rate, rate of permanent neurological deficit as determined by the modified Rankin Score (mRS), rate of second treatment occurrence, and perioperative complication rate were also assessed. RESULTS: A total of 24 studies, including 54 patients with 56 non-trunk BAPAs, were included. The mean maximum aneurysm diameter was 2.70 mm (range 1-10). A diagnosis was achieved with the initial DSA in 50.0% (27/54) of the patients. A conservative approach was used in 16 patients while active treatment was used in the other 38. Thirteen of 15 (86.7%) patients in the conservative group and 27/34 (79.4%) in the active treatment group had an mRS score 0-2. A non-significant higher odds of a positive outcome was observed in the conservative group (OR 1.51, 95% CI 0.50 to 4.54). The event-related mortality rate was 3.55% (3/54) with one procedure-related death in the active treatment group. CONCLUSIONS: In patients with non-trunk BAPAs unamenable to active treatment, conservative approaches may result in acceptable functional outcomes and low morbidity. Small sample sizes and under-reporting of outcomes warrant further study.

Feasibility study for use of angiographic parametric imaging and deep neural networks for intracranial aneurysm occlusion prediction.

BACKGROUND: Angiographic parametric imaging (API), based on digital subtraction angiography (DSA), is a quantitative imaging tool that may be used to extract contrast flow parameters related to hemodynamic conditions in abnormal pathologies such as intracranial aneurysms (IAs). OBJECTIVE: To investigate the feasibility of using deep neural networks (DNNs) and API to predict IA occlusion using pre- and post-intervention DSAs. METHODS: We analyzed DSA images of IAs pre- and post-treatment to extract API parameters in the IA dome and the corresponding main artery (un-normalized data). We implemented a two-step correction to account for injection variability (normalized data) and projection foreshortening (relative data). A DNN was trained to predict a binary IA occlusion outcome: occluded/unoccluded. Network performance was assessed with area under the receiver operating characteristic curve (AUROC) and classification accuracy. To evaluate the effect of the proposed corrections, prediction accuracy analysis was performed after each normalization step. RESULTS: The study included 190 IAs. The mean and median duration between treatment and follow-up was 9.8 and 8.0 months, respectively. For the un-normalized, normalized, and relative subgroups, the DNN average prediction accuracies for IA occlusion were 62.5% (95% CI 60.5% to 64.4%), 70.8% (95% CI 68.2% to 73.4%), and 77.9% (95% CI 76.2% to 79.6%). The average AUROCs for the same subgroups were 0.48 (0.44-0.52), 0.67 (0.61-0.73), and 0.77 (0.74-0.80). CONCLUSIONS: The study demonstrated the feasibility of using API and DNNs to predict IA occlusion using only pre- and post-intervention angiographic information.

Aneurysm characteristics, coil packing, and post-coiling hemodynamics affect long-term treatment outcome.

BACKGROUND: Recurrence of intracranial aneurysms after endovascular coiling is a serious clinical concern. OBJECTIVE: We hypothesized that recurrence is associated with aneurysm morphology and flow, as well as the coil intervention and the induced flow modifications. METHODS: We collected 52 primary-coiling aneurysm cases that were either occluded (n=34) or recurrent (n=18) at >1 year follow-up. We created aneurysm models from pre-coiling digital subtraction angiographic images, calculated aneurysm morphology, simulated pre-coiling hemodynamics, modeled coil deployment, and obtained post-coiling hemodynamics for each case. We performed univariable analysis on 26 morphologic, treatment-specific, and hemodynamic parameters to distinguish between recurrent and occluded groups, and multivariable analysis to identify independently significant parameters associated with recurrence. Univariable analysis was also performed on ruptured and unruptured aneurysm subcohorts separately to investigate if they shared specific significant parameters. RESULTS: Recurrence was associated with pre-coiling aneurysm morphologic and flow parameters including larger size (maximum dimension and volume), larger neck (diameter, area, and neck-to-parent-artery ratio), and higher flow momentum and kinetic energy. Recurrence was also associated with lower coil packing (packing density and uncoiled volume), higher post-treatment flow (velocity, momentum, and kinetic energy), lower post-treatment washout time, and higher post-treatment impingement force at the neck. Multivariable analysis identified two aneurysmal characteristics (neck diameter and pre-coiling flow kinetic energy), one coil packing parameter (uncoiled volume), and one post-treatment hemodynamic parameter (flow momentum) that were independently associated with recurrence. In ruptured aneurysms, recurrence was associated with larger neck (diameter and area), whereas in unruptured aneurysms, recurrence was associated with larger size (maximum dimension and volume). In both subcohorts, recurrence was associated with higher post-coiling flow momentum and kinetic energy. CONCLUSION: Recurrence at >1 year after coil treatment is associated with intrinsic aneurysm characteristics, coiling itself, and flow changes induced by coiling. Larger aneurysm size and neck, less coil packing, and higher intra-aneurysmal flow before and after coiling predict recurrence.

Exploring Reperfusion Following Endovascular Thrombectomy.

Background and Purpose- Cerebral perfusion in acute ischemic stroke patients is often assessed before endovascular thrombectomy (EVT), but rarely after. Perfusion data obtained following EVT may provide additional prognostic information. We developed a tool to quantitatively derive perfusion measurements from digital subtraction angiography (DSA) data and examined perfusion in patients following EVT. Methods- Source DSA images from acute anterior circulation stroke patients undergoing EVT were retrospectively assessed. Following deconvolution, maps of mean transit time (MTT) were generated from post-EVT DSA source data. Thrombolysis in Cerebral Infarction grades and MTT in patients with and without hemorrhagic transformation (HT) at 24 hours were compared. Receiver operating characteristic modeling was used to classify the presence/absence of HT at 24 hours by MTT. Results- Perfusion maps were generated in 50 patients using DSA acquisitions that were a median (interquartile range) of 9 (8-10) seconds in duration. The median post-EVT MTT within the affected territory was 2.6 (2.2-3.3) seconds. HT was observed on follow-up computed tomography in 16 (32%) patients. Thrombolysis in Cerebral Infarction grades did not differ in patients with HT from those without (P=0.575). Post-EVT MTT maps demonstrated focal areas of hyperperfusion (n=8) or persisting hypoperfusion (n=3) corresponding to the regions where HT later developed. The relationship between MTT and HT was U-shaped; HT occurred in patients at both the lowest and highest extremes of MTT. An MTT threshold <2 or >4 seconds was 81% sensitive and 94% specific for classifying the presence of HT at follow-up. Conclusions- Perfusion measurements can be obtained using DSA perfusion with minimal changes to current stroke protocols. Perfusion imaging post-recanalization may have additional clinical utility beyond visual assessment of source angiographic images alone.

Progressive thrombosis of unruptured aneurysms after coil embolization: analysis of 255 consecutive aneurysms.

INTRODUCTION: We have observed that aneurysms treated by insufficient coil embolization and filled with contrast agent immediately after the procedure are often completely occluded at follow-up. However, there are limited studies showing progressive thrombosis of aneurysms after coil embolization. Herein, we describe our experience with coil embolization for aneurysms, and discuss the factors involved in progressive thrombosis. METHODS: A total of 255 aneurysms treated by coil embolization in our institute between January 2011 and June 2017 and observed >6 months were included. 'Progressive thrombosis' indicated that aneurysms that were neck remnant (NR) or dome filling (DF) immediately after coil embolization changed to complete obliteration (CO) at the 6-month follow-up digital subtraction angiography. The factors involved in progressive thrombosis were assessed. RESULTS: In all aneurysms (n=255), 24 (9.4%) were CO, 82 (32.2%) were NR, and 149 (58.4%) were DF immediately after the procedure. At 6-month digital subtraction angiography, 123 (48.2%) were CO, 95 (37.3%) were NR, and 37 (14.5%) were DF. Retreatment for major recanalization was performed in eight cases (3.1%). One hundred and three aneurysms showed progressive thrombosis. There were significant differences in aneurysm location (P=0.0002), aneurysm dome diameter (P=0.0015), aneurysm neck diameter (P=0.0068), volume embolization ratio (P=0.0054), and endovascular procedure with stent (P=0.0264) between the progressive thrombosis and no thrombosis groups. CONCLUSIONS: Progressive thrombosis can occur in aneurysms after coil embolization depending on aneurysm location and size, and stent use. Thus, the degree of coil embolization and combination with a stent should be adjusted depending on aneurysm type.

A new set of eyes: development of a novel microangioscope for neurointerventional surgery.

BACKGROUND: Endovascular technological advances have revolutionized the field of neurovascular surgery and have become the mainstay of treatment for many cerebrovascular pathologies. Digital subtraction angiography (DSA) is the 'gold standard' for visualization of the vasculature and deployment of endovascular devices. Nonetheless, with recent technological advances in optics, angioscopy has emerged as a potentially important adjunct to DSA. Angioscopy can offer direct visualization of the intracranial vasculature, and direct observation and inspection of device deployment. However, previous iterations of this technology have not been sufficiently miniaturized or practical for modern neurointerventional practice. OBJECTIVE: To describe the evolution, development, and design of a microangioscope that offers both high-quality direct visualization and the miniaturization necessary to navigate in the small intracranial vessels and provide examples of its potential applications in the diagnosis and treatment of cerebrovascular pathologies using an in vivo porcine model. METHODS: In this proof-of-concept study we introduce a novel microangioscope, designed from coherent fiber bundle technology. The microangioscope is smaller than any previously described angioscope, at 1.7 F, while maintaining high-resolution images. A porcine model is used to demonstrate the resolution of the images in vivo. RESULTS: Video recordings of the microangioscope show the versatility of the camera mounted on different microcatheters and its ability to navigate external carotid artery branches. The microangioscope is also shown to be able to resolve the subtle differences between red and white thrombi in a porcine model. CONCLUSION: A new microangioscope, based on miniaturized fiber optic technology, offers a potentially revolutionary way to visualize the intracranial vascular space.

A Meta-Analysis of Risk Factors for the Formation of de novo Intracranial Aneurysms.

BACKGROUND: Understanding the risk factors for the formation of de novo intracranial aneurysms (IAs) is important for patients who have ever suffered a cerebral aneurysm. OBJECTIVE: To estimate the risk factors for the development of a de novo IA to identify which patients need more aggressive surveillance after aneurysm treatment. METHODS: We followed the preferred reporting items for systematic reviews and meta-analyses guidelines and searched the PubMed, CENTRAL, EMBASE, and LILACS databases using the key words cerebral aneurysms, de novo, IAs, risk factors combined using and/or. The search was performed in July 2017.We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using RevMan 5.3 (Cochrane, London, United Kingdom) to evaluate risk factors. Statistical significance was set at P < .05. RESULTS: The analysis included 14 studies involving 6389 patients, of whom 197 patients had de novo IAs. The main risk factors for formation included sex (OR = 1.82, 95% CI [1.30,2.56], P = .0005, female vs male), age <40 yr (OR = 2.96, 95% CI [1.76,4.96], P < .0001), family history (OR = 2.05, 95% CI [1.07,3.93], P = .03), smoking history (OR = 2.73, 95% CI [1.81,4.12], P < .0001), and multiple saccular intracranial aneurysms (sIAs) at first diagnosis (OR = 2.10, 95% CI [1.12,3.91], P = .02), internal carotid artery (ICA) as the initial site (OR = 2.58, 95% CI [1.43,4.68], P = .002). Heterogeneous analysis showed that these I2 were less than 50% and the results were reliable. CONCLUSION: Observational evidence identified multiple clinical and anatomic risk factors for the formation of de novo IAs, including female sex, age <40 yr, family history, smoking history, multiple sIAs at first diagnosis, and IC as the initial site. More aggressive long-term angiographic follow-up with digital subtraction angiography, computed tomography angiography, or magnetic resonance angiography is recommended for these patients.

Transient in-stent stenosis at mid-term angiographic follow-up in patients treated with SILK flow diverter stents: incidence, clinical significance and long-term follow-up.

BACKGROUND: Little is known about in-stent stenosis (ISS) in patients with aneurysms treated with flow diverter (FD) stents. The reported incidence in the literature varies significantly. OBJECTIVE: The aim of this study was to assess the incidence, severity, distribution, clinical significance, and possible predictors for ISS. METHODS: Between July 2012 and June 2016 we retrospectively reviewed all patients treated with SILK FDs in our center. Only cases with short-term (4±2 months) and long-term (>1 year) follow-ups with digital subtraction angiograms were included. ISS was graded as mild (<25%), moderate (25-50%) or severe (>50%). The following predictors for ISS were assessed: gender, age, the presence of subarachnoid hemorrhage, aneurysm size, location, occlusion status, and post-stenting angioplasty. RESULTS: Thirty-six patients met the inclusion criteria. At mid-term follow-up, ISS was observed in 16/36 patients (44%). Eleven patients (69%) had mild ISS, three (19%) moderate, and two (12%) severe ISS. ISS was diffuse in 11 patients (69%) and focal in five patients (31%). All patients were asymptomatic. Thirteen patients were maintained on dual antiplatelet therapy and three on aspirin alone. At long-term follow-up, complete ISS resolution was seen in 11 patients, improvement in three and worsening in two patients. No de novo ISS occurrence was observed. On univariate analysis there was no significant predictor for ISS. CONCLUSIONS: Transient ISS after FD deployment is a common asymptomatic finding on mid-term angiographic follow-up. Complete resolution or improvement at long-term follow-up is seen in most patients who are maintained on dual antiplatelet therapy.

Effect of Age on Cerebral Arteriovenous Malformation Draining Vein Stenosis.

OBJECTIVE: The pathogenesis of venous intimal hyperplasia and venous outflow stenosis associated with cerebral arteriovenous malformation (AVM) draining veins is poorly understood. We sought to determine the relationship between venous stenosis and age. METHODS: All patients with an AVM seen at our institution between 1990 and 2016 who underwent a diagnostic cerebral angiogram were retrospectively reviewed. Draining vein stenosis was measured from angiograms before any treatment. The relationship between venous stenosis and age was assessed. RESULTS: We included 281 patients (mean age 39 years, age range 3-83 years, 55% male). Venous stenosis measuring ≥50% was present in 59 patients (21% of cohort). Peak age at presentation was 25-29 years, whereas peak frequency of venous stenosis ≥50% was 50-54 years. Venous stenosis was present in a significantly higher proportion of patients ≥50 years versus <50 years (P = 0.03). Mean percentage stenosis was significantly higher in patients ≥50 years versus <50 years (32% vs. 22%, P = 0.001). CONCLUSIONS: Clinically significant cerebral AVM draining vein stenosis appears to be associated with older age, suggesting that venous stenosis is a progressive disease that occurs by the same process that leads to intimal hyperplasia. These results should be confirmed with a population-based longitudinal study.

Infectious intracranial aneurysms: a systematic review of epidemiology, management, and outcomes.

Infectious intracranial aneurysms (IIAs) are a rare cerebrovascular complication of systemic infections induced by microbial infiltration and degradation of the arterial vessel wall. Studies on the epidemiology and management of IIAs are limited to case reports and retrospective single-center studies, and report a large variability in epidemiological features, management, and outcomes due to the limited sample size. We conducted a systematic review of all published papers on IIAs in the English literature using MEDLINE and SCOPUS database from January 1950 to June 2017. A total of 288 publications describing 1191 patients with IIA (1398 aneurysms) were included and reviewed for epidemiological features, disease features, treatment and outcome. All patients were merged into a single cohort and summary data are presented. The majority of reported IIAs are distally located, relatively small (<5 mm), involve the anterior circulation, are associated with a relatively high rate of rupture, and demonstrate a propensity to multiplicity of aneurysms. Sensitive diagnosis of IIAs requires digital subtraction angiography and not CT angiography or MR angiography. Treatment of ruptured, symptomatic, or enlarging IIAs has evolved over the last 50 years. Endovascular therapy is associated with a high success rate and low morbidity compared with microsurgical and medical management. A treatment algorithm for the management of patients with IIA in various contexts is proposed and the need for prospective multicenter studies is emphasized.

Recrudescence of Symptoms of Remote Ischemic Stroke After a Cerebral Angiogram.

BACKGROUND: Ischemic stroke recrudescence, or reappearance of previously resolved symptoms of ischemic stroke, may occur after physiologic stress. Although generally thought to be uncommon, this syndrome may account for a significant proportion of stroke mimics. CASE DESCRIPTION: A 67-year-old man was admitted with a Hunt and Hess grade 2 spontaneous subarachnoid hemorrhage. He underwent digital subtraction cerebral angiography as part of imaging evaluation. About 30 minutes after the procedure, he developed dysarthria, right facial droop, and right pronator drift. The patient and family denied a history of similar symptoms or previous ischemic stroke. Brain magnetic resonance imaging demonstrated a remote left lacunar infarction. The symptoms resolved after 24 hours and were attributed to recrudescence of the patient's previous lacunar infarction. The physiological stress of the subarachnoid hemorrhage combined with the cerebral angiogram likely triggered the event. CONCLUSIONS: Recrudescence of symptoms of a previous stroke may be initiated by subarachnoid hemorrhage and/or a cerebral angiogram. The possibility of ischemic stroke recrudescence should be kept in mind as a possible stroke mimic.

Long-Term Outcomes of Single-Session Stereotactic Radiosurgery for Cerebellar Arteriovenous Malformation, with a Median Follow-Up of 10 Years.

OBJECTIVE: Cerebellar arteriovenous malformation (C-AVM) is poorly tolerated because of its aggressive natural history. The aim of this study was to delineate long-term outcomes of Gamma Knife stereotactic radiosurgery (GKRS) for C-AVM. METHODS: The outcomes of 45 patients who underwent GKRS for C-AVMs at our institution were retrospectively analyzed. Event-free survival was defined as free from any neurologic deficits caused by AVMs or adverse phenomena from the treatment. RESULTS: The median age and follow-up were 41 years (range, 6-77 years) and 120 months (range, 5-291 months), respectively. The median volume and Pollock-Flickinger radiosurgical AVM score were 1.3 cm3 (range, 0.1-8.3 cm3) and 1.26 (range, 0.5-2.06), respectively. Actuarial obliteration rates were 46%, 75%, and 90% at 3, 5, and 6 years, respectively. Multivariate analysis showed that the maximal diameter ≤15 mm (P = 0.021) and margin dose >20 Gy (P = 0.0008) were significantly associated with better obliteration. Four patients experienced posttreatment hemorrhages, and annual hemorrhage rates were 1.9% and 0.30% before and after obliteration, respectively. One patient died because of hemorrhage, whereas the other 3 patients spontaneously recovered. Perifocal edema was confirmed in 8 (16%); however, no symptomatic edema was observed. Overall, neurologic deteriorations were noted in 4 patients; 3 were because of posttreatment hemorrhage, and 1 was because of pretreatment angiography. The event-free survival rates were 96%, 93%, and 93% at 4, 10, and 15 years, respectively. CONCLUSIONS: GKRS is a reasonable intervention for C-AVMs. Symptomatic complications are rare, and the long-term outcomes are favorable.

Recent developments of imaging modalities of carotid artery stenting.

Compared with conventional angiogram-guided procedure, intravascular imaging modalities give us a lot of useful information to make the procedure better. Intravascular imaging modalities give us the information about lesion characters, reference vessel diameter and the interaction between the stent strut and the plaque such as stent strut malapposition or plaque prolapse in real time during the procedure. We can change our strategy according to this information. Intravascular ultrasound (IVUS) is a most common intravascular imaging modality during carotid artery stenting (CAS) in these days. Its advantage is easy to use compared with optical coherence tomograpy (OCT) which has been reported recently in some case reports or case series. However, due to its high resolution, OCT provides more detailed information especially about plaque prolapse and strut malapposition. IVUS and OCT have a potential to improve acute result and reduce the procedural complication by providing the data of lesion character, reference vessel diameter and the interaction of stent strut and vessel wall. Interventionalists who perform CAS procedure should acquire proficiency in imaging modalities during CAS procedure.

Time-Resolved C-Arm Computed Tomographic Angiography Derived From Computed Tomographic Perfusion Acquisition: New Capability for One-Stop-Shop Acute Ischemic Stroke Treatment in the Angiosuite.

BACKGROUND AND PURPOSE: Multimodal imaging using cone beam C-arm computed tomography (CT) may shorten the delay from ictus to revascularization for acute ischemic stroke patients with a large vessel occlusion. Largely because of limited temporal resolution, reconstruction of time-resolved CT angiography (CTA) from these systems has not yielded satisfactory results. We evaluated the image quality and diagnostic value of time-resolved C-arm CTA reconstructed using novel image processing algorithms. METHODS: Studies were done under an Institutional Review Board approved protocol. Postprocessing of data from 21 C-arm CT dynamic perfusion acquisitions from 17 patients with acute ischemic stroke were done to derive time-resolved C-arm CTA images. Two observers independently evaluated image quality and diagnostic content for each case. ICC and receiver-operating characteristic analysis were performed to evaluate interobserver agreement and diagnostic value of this novel imaging modality. RESULTS: Time-resolved C-arm CTA images were successfully generated from 20 data sets (95.2%, 20/21). Two observers agreed well that the image quality for large cerebral arteries was good but was more limited for small cerebral arteries (distal to M1, A1, and P1). receiver-operating characteristic curves demonstrated excellent diagnostic value for detecting large vessel occlusions (area under the curve=0.987-1). CONCLUSIONS: Time-resolved CTAs derived from C-arm CT perfusion acquisitions provide high quality images that allowed accurate diagnosis of large vessel occlusions. Although image quality of smaller arteries in this study was not optimal ongoing modifications of the postprocessing algorithm will likely remove this limitation. Adding time-resolved C-arm CTAs to the capabilities of the angiography suite further enhances its suitability as a one-stop shop for care for patients with acute ischemic stroke.

Evolution in the Treatment of Delayed Postpancreatectomy Hemorrhage: Surgery to Interventional Radiology.

OBJECTIVES: We summarized a single center's evolution in the management of postpancreatectomy hemorrhage (PPH) from surgical toward endovascular management. METHODS: Between 2003 and 2013, 337 patients underwent Whipple procedures. Using the International Study Group of Pancreatic Surgery (ISGPS) consensus definition, patients with PPH were identified and retrospectively analyzed for the presentation of hemorrhage, type of intervention, and 90-day mortality outcome measures. RESULTS: Management evolved from operative intervention alone, to combined operative and on-table angiographic intervention, to endovascular intervention alone. The prevalence of PPH was 3.0%. Delayed PPH occurred with a mean of 13.8 days. On angiography, visceral arteries affected were the gastroduodenal artery, hepatic artery, jejunal branches of the superior mesenteric artery, pancreaticoduodenal artery, and inferior phrenic artery. Ninety-day mortality for PPH was 20%. From early to recent experience, the mortality rate was 100% for operative intervention alone, 25% for combined operative and on-table angiographic intervention, and 0% for endovascular intervention alone. CONCLUSIONS: Our 10-year experience supports current algorithms in the management of PPH. Key considerations include the recognition of the sentinel bleed, the presence of a pancreatic fistula, and the initial operative role of a long gastroduodenal artery stump with radiopaque marker for safe and effective embolization should PPH occur.

Time-resolved angiography: Past, present, and future.

The introduction of digital subtraction angiography (DSA) in 1980 provided a method for real time 2D subtraction imaging. Later, 4D magnetic resonance (MR) angiography emerged beginning with techniques like Keyhole and time-resolved imaging of contrast kinetics (TRICKS) that provided frame rates of one every 5 seconds with limited spatial resolution. Undersampled radial acquisition was subsequently developed. The 3D vastly undersampled isotropic projection (VIPR) technique allowed undersampling factors of 30-40. Its combination with phase contrast displays time-resolved flow dynamics within the cardiac cycle and has enabled the measurement of pressure gradients in small vessels. Meanwhile similar accelerations were achieved using Cartesian acquisition with projection reconstruction (CAPR), a Cartesian acquisition with 2D parallel imaging. Further acceleration is provided by constrained reconstruction techniques such as highly constrained back-projection reconstruction (HYPR) and its derivatives, which permit acceleration factors approaching 1000. Hybrid MRA combines a separate phase contrast, time-of flight, or contrast-enhanced acquisition to constrain the reconstruction of contrast-enhanced time frames providing exceptional spatial and temporal resolution and signal-to-noise ratio (SNR). This can be extended to x-ray imaging where a 3D DSA examination can be used to constrain the reconstruction of time-resolved 3D volumes. Each 4D DSA (time-resolved 3D DSA) frame provides spatial resolution and SNR comparable to 3D DSA, thus removing a major limitation of intravenous DSA. Similar techniques have provided the ability to do 4D fluoroscopy.

Subtraction coronary CT angiography for calcified lesions.

One of the main problems in coronary angiography using 64-row computed tomography (CT) is that the presence of severe calcification interferes with the assessment of lesions, which reduces diagnostic accuracy and may even make assessment of some coronary artery segments impossible. With 320-row CT, it is possible to avoid this problem by performing subtraction coronary CT, which fully exploits the performance capabilities of the CT system. However, subtraction coronary CT has several limitations. When these limitations have been overcome, this technique is expected to become a useful method for assessing patients with severe calcification and evaluating coronary artery stents.