Vessel territory mapping after cerebral revascularization surgery using selective angiographic flat detector perfusion imaging.

The technical feasibility and diagnostic potential of angiographic flat-detector perfusion imaging technique, combining digital subtraction angiography with a flat-detector computed tomography steady-state perfusion imaging, was explored in patients treated with direct or indirect revascularization surgery. This short communication is about an imaging modality with great potential for evaluation, comparison and grading of vascular perfusion territory areas and anatomical location selectively perfused by direct and indirect cerebral bypasses.

Repeatability, and Intra-Observer and Interobserver Agreement of Two Dimensional Perfusion Angiography in Patients with Chronic Limb Threatening Ischaemia.

OBJECTIVE: Two dimensional (2D) perfusion angiography is a method that provides quantitative foot perfusion information from standard digital subtraction angiography acquisitions. The aim of this study was to test the reliability of this method in patients with chronic limb threatening ischaemia (CLTI) by investigating repeatability, and intra-observer and interobserver agreement. METHODS: Twenty patients with CLTI and a below the knee endovascular revascularisation were included in a prospective clinical study. Prior to treatment two perfusion angiography runs were acquired with a five minute interval without performing an intervention. In these recordings, regions of interest were selected and time density curves and perfusion parameters were determined. To investigate intra-observer agreement one observer performed five measurements on the same acquisition for each patient. To investigate interobserver agreement three observers performed measurements on the same acquisition for each patient. Results were presented in Bland-Altman plots and as the intraclass correlation coefficient per parameter. RESULTS: Two patients were excluded from repeatability analyses because of major motion artefacts. Repeatability analyses of the 18 remaining patients showed excellent correlation for every parameter (> .96). Intra-observer and interobserver agreement for all 20 patients were excellent for all parameters (1.00). CONCLUSION: Repeatability and intra-observer and interobserver agreement of 2D perfusion angiography in patients with CLTI were found to be excellent. It is therefore a reliable tool when used according to the standardised methods described in this study.

Is the unruptured intracranial aneurysm treatment score (UIATS) sensitive enough to detect aneurysms at risk of rupture?

To evaluate if the unruptured intracranial aneurysm treatment score (UIATS) is a sensitive tool to detect aneurysms at risk of rupture, we conducted an a posteriori retrospective study on ruptured intracranial aneurysms. We performed a retrospective analysis of adult patients admitted to our center from January 2010 to April 2016 with aneurysmal subarachnoid hemorrhage. The UIATS was applied to all ruptured aneurysms. Patients for whom the UIATS recommended treatment were labeled as "true positives," whereas patients for whom the UIATS recommended observation were labeled as "false negatives." Patients for whom the UIATS was inconclusive were excluded from the final analysis. Based on the UIATS recommendation, a sensitivity analysis was performed. A total of 262 patients with aneurysmal subarachnoid hemorrhage were screened. Of these, 212 were included in our analysis. Median age was 53 years (23-90). Most patients were females (n = 134, 63%), with an equal distribution between low-grade and high-grade hemorrhages (Hunt & Hess ≥ 3 n = 107, 50%). UIATS recommended treatment in n = 52, 25% cases (TP), was inconclusive in n = 93, 44% (excluded), and recommended observation in n = 67, 32% (FN). Based on these data, the UIATS showed a sensitivity of 44% (CI 35-53%). The UIATS exhibits rather low sensitivity for detecting aneurysms at risk of rupture.

Acute non-traumatic subdural hematoma induced by intracranial aneurysm rupture: A case report and systematic review of the literature.

RATIONALE: Intracranial aneurysm with the first manifestation of acute subdural hematoma (aSDH) is rare in the field of neurosurgery. Usually subarachnoid hemorrhage or intracranial hematoma happens after the rupture of an intracranial aneurysm, whereas trauma is the primary cause of aSDH. PATIENT CONCERNS: Here, we present the case of a 71-year-old woman who presented with spontaneous aSDH with progressive headache and vomiting. DIAGNOSIS: Urgent head computed tomography (CT) identified an aSHD, but the patient had no history of trauma. CT angiography (CTA) identified the cause of the aSDH as rupture of an intracranial aneurysm in the left middle cerebral artery. INTERVENTIONS: Emergent craniotomy with hematoma evacuation was performed. OUTCOMES: Due to prompt diagnosis and appropriate intervention, the patient recovered fully with no disability. LESSONS: This unique case demonstrates that aSDH caused by intracranial aneurysm rupture requires timely identification and appropriate action to prevent adverse outcomes. We performed a comprehensive systematic literature review to examine the etiology and pathogenesis of non-traumatic aSDH. Furthermore, digital subtraction angiography should be considered in patients diagnosed with an aSDH with no known cause.

Discrepancy between MRA and DSA in identifying the shape of small intracranial aneurysms.

OBJECTIVE: The authors evaluated the sensitivity and accuracy of MRA in identifying the shape of small-sized unruptured intracranial aneurysms. METHODS: Small (< 7 mm) unruptured intracranial aneurysms initially detected by MRA and confirmed by DSA between January 2017 and December 2018 were morphologically reviewed by neuroradiologists. Regularity or irregularity of aneurysm shape was analyzed by two independent reviewers using MRA without DSA results. DSA findings served as the reference standard for aneurysm shape. Irregular shape, which in small aneurysms is associated with a higher likelihood of rupture, was defined as positive, and MRA sensitivity, specificity, and accuracy were determined by using evaluations based on location, size, and MRA magnetic strength (1.5T vs 3T MRA). Multivariate analysis was performed to determine risk factors for false-negative MRA results for irregularly shaped aneurysms. RESULTS: In total, 652 unruptured intracranial aneurysms in 530 patients were reviewed for this study. For detecting aneurysm shape irregularity, the overall MRA sensitivity was 60.4% for reviewer 1 and 60.9% for reviewer 2. Anterior cerebral artery aneurysms had the lowest sensitivity for location (36.7% for reviewer 1, 46.9% for reviewer 2); aneurysms sized < 3 mm had the lowest sensitivity for size (26.7% for both reviewers); and 1.5T MRA had lower sensitivity and accuracy than 3T MRA. In multivariate analysis, location, size, and magnetic strength of MRA were independent risk factors for false-negative MRA results for irregularly shaped aneurysms. CONCLUSIONS: MRA had a low sensitivity for detecting the irregular shape of small intracranial aneurysms. In particular, anterior cerebral artery location, aneurysm size < 3 mm, and detection with 1.5T MRA were associated with a higher risk of irregularly shaped aneurysms being misjudged as regular.

Accuracy of optical coherence tomography imaging in assessing aneurysmal remnants after flow diversion.

BACKGROUND: Optical coherence tomography (OCT) is an ultra-high resolution real-time intravascular imaging method that is gaining interest in cerebrovascular applications. OBJECTIVE: To compare, in a rabbit elastase aneurysm model, digital subtraction angiography (DSA) and OCT as diagnostic tools for the assessment of aneurysmal remnants and baseline characteristics of aneurysms after flow diverter (FD) implantation. METHODS: With Institutional Animal Care and Use Committee approval, saccular aneurysms were created in 28 rabbits and treated with Derivo FDs. DSA was performed before, and immediately after, stent implantation. As a follow-up, DSA and OCT were performed 28 days after device implantation. RESULTS: DSA and OCT were successfully performed in 23 cases. OCT could not be achieved in 5 cases owing to navigational difficulties in the stent lumen with the OCT catheter. Residual aneurysms were significantly more often visible with OCT (18/23 (78%) than with DSA 12/23 (52%), p = 0.031). CONCLUSION: OCT was more sensitive than conventional angiography for the assessment of residual aneurysms at 28 days after FD implantation in an animal model.

Digital Subtraction Angiography Prior to an Amputation for Critical Limb Ischemia (CLI): An Expert Recommendation Statement From the CLI Global Society to Optimize Limb Salvage.

Despite recent guideline updates on peripheral artery disease (PAD) and critical limb ischemia (CLI) treatment, the optimal treatment for CLI is still being debated. As a result, care is inconsistent, with many CLI patients undergoing an amputation prior to what many consider to be mandatory: consultation with an interdisciplinary specialty care team and a comprehensive imaging assessment. More importantly, quality imaging is critical in CLI patients with below-the-knee disease. Therefore, the CLI Global Society has put forth an interdisciplinary expert recommendation for superselective digital subtraction angiography (DSA) that includes the ankle and foot in properly indicated CLI patients to optimize limb salvage. A recommended imaging algorithm for CLI patients is included.

Prediction of degree of carotid stenosis with the transluminal attenuation difference ratio.

PURPOSE: We aimed to assess the diagnostic performance of transluminal attenuation difference (TAD) in predicting the severity of internal carotid artery (ICA) stenosis. METHODS: The study cohort consisted of 48 patients with <50% stenosis, 50%-69% stenosis, 70%-99% stenosis, and 51 controls without plaque development in ICA. A total of 143 measurements were performed through right and left internal and common carotid arteries. The TAD ratio was calculated as the difference between the mean attenuation values of the common carotid artery (CCA) and ICA, divided by the MAV of the CCA, multiplied by 100. RESULTS: TAD ratio was significantly higher in severe (>70%) stenosis compared with control arteries and low-moderate stenosis. A TAD ratio cutoff of 4.5 predicted 70%-99% stenosis with a sensitivity of 100% and specificity of 93%. The inter- and intraobserver agreements in TAD measurements were almost perfect (ICC, 0.89-0.86). CONCLUSION: Assessment of TAD ratio predicts the degree of stenosis in concordance with NASCET system.

Evaluation of the angiographic outcomes after clipping of intracranial aneurysms: determination of predisposing factors for occurrence of aneurysm remnants.

Objectives: Aneurysm remnants after microsurgical clipping have a risk of regrowth and rupture and have not been validated in the era of three-dimensional angiography. Therefore, this study aimed to evaluate the angiographic outcome using three-dimensional rotational images and determine the predictors for remnants after microsurgical clipping.Methods: Between January 2014 and May 2017, 139 aneurysms in 106 patients who were treated with microsurgical clipping, were eligible for this study. For the determination of aneurysm remnants after microsurgical clipping, the angiographic outcomes were evaluated using follow-up digital subtraction angiography within 7 days for unruptured aneurysms or within 2 weeks for ruptured aneurysms. According to the Sindou classification, the aneurysm remnants were dichotomized, and subgroup analysis was performed to identify the predictors of aneurysm remnants after clipping with various imaging parameters and clinical information.Results: The overall rate of aneurysm remnants was 29.5% (41/139), in which retreatments were needed in 6.5% (9/139). The neck size and maximum diameter of aneurysms were independent predisposing factors for the aneurysm remnants that need retreatment (OR: 2.30; p < 0.001; OR: 1.38; p < 0.001, respectively).Conclusions: This study demonstrated a low incidence of aneurysm remnants after microsurgical clipping which need to retreatment. However, selective postoperative angiography could provide us clear information of surgical result and evidence for long-term follow-up for some aneurysms with larger neck size (>5.7 mm) and maximum diameter (>7.1 mm).

Automatic radiomic feature extraction using deep learning for angiographic parametric imaging of intracranial aneurysms.

BACKGROUND: Angiographic parametric imaging (API) is an imaging method that uses digital subtraction angiography (DSA) to characterize contrast media dynamics throughout the vasculature. This requires manual placement of a region of interest over a lesion (eg, an aneurysm sac) by an operator. OBJECTIVE: The purpose of our work was to determine if a convolutional neural network (CNN) was able to identify and segment the intracranial aneurysm (IA) sac in a DSA and extract API radiomic features with minimal errors compared with human user results. METHODS: Three hundred and fifty angiographic images of IAs were retrospectively collected. The IAs and surrounding vasculature were manually contoured and the masks put to a CNN tasked with semantic segmentation. The CNN segmentations were assessed for accuracy using the Dice similarity coefficient (DSC) and Jaccard index (JI). Area under the receiver operating characteristic curve (AUROC) was computed. API features based on the CNN segmentation were compared with the human user results. RESULTS: The mean JI was 0.823 (95% CI 0.783 to 0.863) for the IA and 0.737 (95% CI 0.682 to 0.792) for the vasculature. The mean DSC was 0.903 (95% CI 0.867 to 0.937) for the IA and 0.849 (95% CI 0.811 to 0.887) for the vasculature. The mean AUROC was 0.791 (95% CI 0.740 to 0.817) for the IA and 0.715 (95% CI 0.678 to 0.733) for the vasculature. All five API features measured inside the predicted masks were within 18% of those measured inside manually contoured masks. CONCLUSIONS: CNN segmentation of IAs and surrounding vasculature from DSA images is non-inferior to manual contours of aneurysms and can be used in parametric imaging procedures.

Validation and Application for the Berlin Grading System of Moyamoya Disease in Adult Patients.

BACKGROUND: Traditional moyamoya disease (MMD) classification relies on morphological digital subtraction angiography (DSA) assessment, which do not reflect hemodynamic status, clinical symptoms, or surgical treatment outcome. OBJECTIVE: To (1) validate the new Berlin MMD preoperative symptomatology grading system and (2) determine the clinical application of the grading system in predicting radiological and clinical outcomes after surgical revascularization. METHODS: Ninety-six MMD patients (192 hemispheres) with all 3 investigations (DSA, magnetic resonance imaging [MRI], Xenon-CT) performed preoperatively at our institution (2007-2013) were included. Two clinicians independently graded the imaging findings according to the proposed criteria. Patients' modified Rankin Score (mRS) scores (preoperative, postoperative, last follow-up), postoperative infarct (radiological, clinical) were collected and statistical correlations performed. RESULTS: One hundred fifty-seven direct superficial temporal artery-middle cerebral artery bypasses were performed on 96 patients (66 female, mean age 41 yr, mean follow-up 4.3 yr). DSA, MRI, and cerebrovascular reserve capacity were independent factors associated hemispheric symptomatology (when analyzed individually or in the combined grading system). Mild (grade I), moderate (grade II), severe (grade III) were graded in 45, 71, and 76 hemispheres respectively; of which, clinical symptoms were found in 33% of grade I, 92% of grade II, 100% of grade III hemispheres (P < .0001). Two percent of grade I, 11% of grade II, 20% of grade III hemispheres showed postoperative radiological diffusion weighted image-positive ischemic changes or hemorrhage on MRI (P = .018). Clinical postoperative stroke was observed in 1.4% of grade II, 6.6% of grade III hemispheres (P = .077). The grading system also correlated well to dichotomized mRS postoperative outcome. CONCLUSION: The Berlin MMD grading system is able to stratify preoperative hemispheric symptomatology. Furthermore, it correlated with postoperative new ischemic changes on MRI, and showed a strong trend in predicting clinical postoperative stroke.

Usefulness of high-resolution three-dimensional proton density-weighted turbo spin-echo MRI in distinguishing a junctional dilatation from an intracranial aneurysm of the posterior communicating artery: a pilot study.

BACKGROUND: Discriminating a junctional dilatation from a true saccular aneurysm is clinically important. PURPOSE: To evaluate the usefulness of high-resolution three-dimensional proton density-weighted turbo spin-echo magnetic resonance imaging (PD MRI) in distinguishing a junctional dilatation from an aneurysm of the posterior communicating artery (PcomA). METHODS: Eighty-two consecutive patients with 83 PcomA lesions, which were evaluated by time-of-flight (TOF) MR angiography (MRA), PD MRI, and digital subtraction angiography (DSA), were enrolled. These radiologic data were retrospectively and independently reviewed by two neurosurgeons, and each diagnosis based on TOF MRA, PD MRI, and DSA was compared. The diagnostic efficacy (interobserver agreement, intermodality agreement, and diagnostic performance) of PD MRI was compared with that of TOF MRA. RESULTS: PD MRI showed higher AC1 (Gwet's agreement coefficient, PD MRI: 0.8942, 95% CI 0.8204 to 0.968; TOF MRA: 0.7185, 95% CI 0.5753 to 0.8617) and prevalence-adjusted bias-adjusted kappa coefficient (PABAK) (PD MRI: 0.8554, TOF MRA: 0.5904) than TOF MRA for interobserver agreement. For intermodality agreement, PD MRI also showed higher AC1 (PD MRI: 0.9069, 95% CI 0.8374 to 0.9764; TOF MRA: 0.7983, 95% CI 0.6969 to 0.8996) and PABAK (PD MRI: 0.8735, TOF MRA: 0.7289) than TOF MRA. The diagnostic performance of PD MRI was statistically superior to that of TOF MRA in sensitivity, specificity, positive predictive value, and negative predictive value. CONCLUSIONS: PD MRI could provide excellent diagnostic accuracy and better information in distinguishing a junctional dilatation from a true saccular aneurysm of the PcomA compared with TOF MRA.

MRA versus DSA for the follow-up imaging of intracranial aneurysms treated using endovascular techniques: a meta-analysis.

BACKGROUND: Treated aneurysms must be followed over time to ensure durable occlusion, as more than 20% of endovascularly treated aneurysms recur. While digital subtraction angiography (DSA) remains the gold standard, magnetic resonance angiography (MRA) is attractive as a non-invasive follow-up technique. Two different MRA techniques have traditionally been used: time-of-flight (TOF) and contrast-enhanced (CE) MRA. We analysed data from studies comparing MRA techniques with DSA for the follow-up of aneurysms undergoing endovascular treatment. Subgroup analysis of stent-assisted coiling (SAC) and flow diversion (FD) techniques was completed. METHODS: Comprehensive searches using the Embase, PubMed, and Cochrane databases were performed and updated to November 2018. Pooled sensitivity and specificity were calculated using aneurysm occlusion status as defined by the Raymond-Roy occlusion grading scale. RESULTS: The literature search yielded 1579 unique titles. Forty-three studies were included. For TOF-MRA, sensitivity and specificity of all aneurysms undergoing endovascular therapy were 88% and 94%, respectively. For CE-MRA, the sensitivity and specificity were 88% and 96%, respectively. For SAC and FD techniques, sensitivity and specificity of TOF-MRA were 86% and 95%, respectively. CE-MRA had sensitivity and specificity of 90% and 92%. CONCLUSION: MRA is a reliable modality for the follow-up of aneurysms treated using endovascular techniques. While the data are limited, MRA techniques can also be used to reliably follow patients undergoing FD and SAC. However, clinical factors must be used to optimize follow-up regimens for individual patients.

Interobserver agreement on interpretation of conventional dacryocystography and dacryoscintigraphy findings: A retrospective single-centre study.

IMPORTANCE: This study assesses the interobserver agreement on dacryocystography (DCG) and dacryoscintigraphy (DSG) findings. BACKGROUND: There are no standard grading criteria to guide the interpretation of conventional DCG and DSG findings and therefore there may be a degree of subjectivity. This study evaluates the level of interobserver agreement in the interpretation of DCG and DSG findings. DESIGN: A retrospective observational study at the Royal Adelaide Hospital. PARTICIPANTS: A total of 165 patients who presented with epiphora with 276 DCGs and 290 DSGs performed were included in this study. METHODS: DCG and DSG images were obtained, anonymized, randomized and interpreted by three independent oculoplastic surgeons. Standard grading criteria were set for both DCG and DSG images. Data from all observers were analysed for interobserver agreement using Kappa (κ) statistics, generated using a variation of Cohen's kappa for multiple observers. MAIN OUTCOME MEASURES: Level of interobserver agreement (κ values) in the grading of DCG and DSG findings. RESULTS: There was an overall moderate interobserver agreement for DCG findings (κ = 0.55), with the highest agreement on interpreting canalicular obstruction (κ = 0.80), followed by proximal nasolacrimal duct obstruction (κ = 0.67) and normal patency (κ = 0.63). There was an overall fair interobserver agreement for DSG findings (κ = 0.36), with the best being moderate agreement (κ = 0.42-0.50) for interpreting pre-sac delay and post-sac proximal delay. CONCLUSIONS AND RELEVANCE: DCG offers good reliability in interpreting patent and obstructed systems. On the other hand, DSG has poor agreement and highlights some of the limitations in the ability to guide epiphora management.

In vitro accuracy and inter-observer reliability of CT angiography in detecting intracranial aneurysm enlargement.

BACKGROUND AND PURPOSE: To evaluate the accuracy and inter-observer variability when CT angiography is used to identify unruptured intracranial aneurysm growth. METHODS: Two silicone phantom models were used in this study. Each phantom had eight aneurysms of variable size. The size and location of aneurysms in phantom 1 were representative of real patient aneurysms who presented to our institution. Phantom 2 contained aneurysms in the same locations, but with enlargement in various directions. Three blinded board-certified neuroradiologists were asked to identify the size of each aneurysm in three dimensions using CT angiography. The individual enlargement detection rates and inter-observer agreement rates of aneurysm enlargement among the three experts were calculated. RESULTS: The detection rate of aneurysm enlargement in one dimension was 58.3% among the three observers. Accurate detection of enlargement in all dimensions was 12.5% among the three observers. Detection accuracy was not related to the size of enlargement. Significant inter-observer measurement variability was present. CONCLUSION: The use of CT angiography was associated with a poor ability to identify aneurysm enlargementaccurately. Further human studies are required to confirm our findings.

Unique Gadolinium Enhancement Pattern in Spinal Dural Arteriovenous Fistulas.

Importance: Spinal dural arteriovenous fistula (sDAVF) is often misdiagnosed as an inflammatory or a neoplastic myelopathy, often because of intraparenchymal gadolinium enhancement on magnetic resonance imaging (MRI); proper early diagnosis is important because deficits are reversible and a delay in treatment is associated with permanent morbidity. Tortuous flow voids on MRI are not universally present; thus, recognition of a unique gadolinium enhancement pattern may also aid in the early recognition and treatment of sDAVF. Objective: To describe a unique pattern of spinal cord gadolinium enhancement on MRI in sDAVF. Design, Setting, and Participants: This retrospective evaluation included pretreatment MRIs from 80 patients referred to the Mayo Clinic, Rochester, Minnesota, from January 1, 1997, through December 31, 2017, with a confirmed diagnosis of sDAVF and a control group of 144 patients with alternative confirmed myelopathy diagnoses. All participants underwent a neurologic evaluation at the Mayo Clinic. Main Outcomes and Measures: Evidence of at least 1 focal geographic nonenhancing area within a long segment of intense holocord gadolinium enhancement (termed the missing-piece sign) on MRI. Results: Of 51 patients with an sDAVF and a pretreatment MRI with gadolinium enhancement, 44 (86%) had intraparenchymal contrast enhancement, and 19 of these patients (43%) displayed the characteristic missing-piece sign. Of these 19 patients, symptom onset occurred at a median age of 67 years (range, 27-80 years); 15 patients were men. Progressive myelopathy features affecting the lower extremities occurred during a median of 33 months (range, 1-84 months). Eleven patients (58%) received an alternative diagnosis before confirmation of sDAVF. Tortuous flow voids were present on T2-weighted MRI in 13 of 19 patients. More than 1 digital subtraction angiogram was required for 5 patients to confirm the diagnosis. The missing-piece sign was not seen in any patients from the control group. Conclusions and Relevance: This unique gadolinium enhancement pattern in sDAVF was not found in a large control group of patients with other myelopathy. Identifying the missing-piece sign on MRI could potentially result in earlier time to angiography with improved outcomes for patients with an sDAVF.

CT during celiac artery angiography for localization of clinically suspected small insulinomas.

BACKGROUND: To identify location and number of insulinomas before operation is very important for improving the cure rate. The objective of the study was to assess performance of CT during celiac artery angiography for preoperative localization of clinically suspected small insulinomas (< 2 cm in diameter). METHODS: From January 2013 to November 2016, 42 patients with hypoglycemic symptoms underwent celiac artery angiography, superior mesenteric artery angiography and CT during celiac artery angiography by a combined CT/digital subtraction angiography system, MIYABI Angio CT plus an Artiszeeceiling (SIEMENS, Germany). Patient group consisted of 13 males and 29 females, age 17-69 years (average, 45.4 ± 13.5 y). After diagnosis, all 42 patients were operated. Obtained images were retrospectively analyzed and compared with findings from post-operation pathology. RESULTS: All interventional radiology procedures were performed successfully with no complications. Sensitivity of angiography alone for insulinoma was 76.1% (32/42), at combined CT/digital subtraction angiography, 4 more nodules were found (sensitivity, 85.7%, 36/42), while 6 false-negatives were observed (all false negative lesions were less than 2 cm). A total of 64 ml to 80 ml contrast media was used per patient. CONCLUSION: CT during celiac artery angiography is a sensitive diagnostic procedure for localizing insulinomas. Combined with angiography, it can prioritize the pancreatic region for exploration and guide a pancreatic resection. TRIAL REGISTRATION: Ethical approval was obtained from the Hospital Research Ethics Committee. Informed consent was obtained from all patients included in the study. Duan Feng, Bai Yan-hua and Cui Li are co-first authors.

Reference values of vessel diameters, stenosis prevalence, and arterial variations of the lower limb arteries in a male population sample using contrast-enhanced MR angiography.

INTRODUCTION: Morphological characterization of leg arteries is of significant importance to detect vascular remodeling triggered by atherosclerotic changes. We determined reference values of vessel diameters and assessed prevalence of stenosis and arterial variations of the lower limb arteries in a healthy male population sample. METHODS: Gadolinium-enhanced magnetic resonance angiography at 1.5 Tesla was performed in 756 male participants (median age = 52 years, range = 21-82 years) of the population-based Study of Health in Pomerania. Vessel diameters were measured in 9 predefined segments of the pelvic and leg arteries and 95th percentiles were used for upper reference values of means of left and right side arteries. RESULTS: Reference values of vascular diameters decreased from proximal to distal arteries: common iliac = 1.18cm; internal iliac = 0.75cm; external iliac = 1.03cm; proximal femoral = 1.02cm; distal femoral = 0.77cm; popliteal = 0.69cm; anterior tibial = 0.42cm; posterior tibial = 0.38cm; fibular = 0.40cm. Body-surface area indexed reference values increased with age in all segments. A number of 53 subjects (7.0%) had at least one stenosis, mainly in the lower leg arteries anterior tibial (n = 28, 3.7%), posterior tibial (n = 18, 2.4%) and fibular (n = 20, 2.6%). The risk of stenosis increased considerably with age (odds ratio = 1.08; p<0.001). The most common arterial variant was type I-A in both legs (n = 620, 82%). CONCLUSION: We present reference values for different pelvic and leg artery segment diameters in men that decrease from proximal to distal and increase with age. Stenoses were most prevalent in lower leg arteries and type I-A was the most common variant in the lower leg.

Conventional digital subtractional vs non-invasive MR angiography in the assessment of brain arteriovenous malformation.

OBJECTIVES: Digital subtractional angiography (DSA) is the standard method for diagnosis, assessment and management of arteriovenous malformation in the brain. Conventional DSA (cDSA) is an invasive imaging modality that is often indicated before interventional treatments (embolization, open surgery, gamma knife). Here, we aimed to compare this technique with a non-invasive MR angiography (MRI DSA) for brain arteriovenous malformation (bAVM). PATIENTS AND METHODS: Fourteen patients with ruptured brain AVM underwent embolization treatment pre-operation. Imaging was performed for all patients using MRI (1.5 T). After injecting contrast Gadolinium, dynamic MRI was performed with 40 phases, each phase of a duration of 1.2 s and having 70 images. The MRI results were independently assessed by experienced radiologist blinded to the cDSA. RESULTS: The AVM nidus was depicted in all patients using cDSA and MRI DSA; there was an excellent correlation between these techniques in terms of the maximum diameter and Spetzler Martin grading. Of the fourteen patients, the drainage vein was depicted in 13 by both cDSA and MRI DSA showing excellent correlation between the techniques used. CONCLUSION: MRI DSA is a non-invasive imaging modality that can give the images in dynamic view. It can be considered as an adjunctive method with cDSA to plan the strategy treatment for bAVM.

Standardization of a Carbon Dioxide Automated System for Endovascular Aortic Aneurysm Repair.

BACKGROUND: Endovascular aortic repair (EVAR) is presently the preferred treatment for abdominal aortic aneurysm; however, it requires the injection of a contrast medium, which can hamper the renal function. Other nontoxic agents such as carbon dioxide (CO2) have been sporadically tested in this setting with uncertain results. The aim of the study is to investigate the efficacy of a new standardized CO2 injection method in standard EVAR procedures. METHODS: Between August and October 2016, 31 consecutive patients (median age 76.1 [interquartile range {IQR}: 7.4] years) were submitted to standard EVAR. Proximal and distal endograft landing zones were identified by the injection of 100 mL of CO2 at 300 mm Hg, through an 11 cm 10F femoral sheath by a specifically manufactured automated injection device (Angiodroid Srl, San Lazzaro, Bologna, Italy). Before EVAR deployment, a confirmative injection with a conventional contrast medium was accomplished. The possibility of precisely visualizing the proximal and distal landing zones by CO2 digital subtraction angiography (DSA) was evaluated considering the contrast medium injection obtained in the same procedure as a gold standard. Similarly, the possible presence of endoleak was assessed at the end of the procedure by the 2 techniques. RESULTS: CO2 DSA allowed to identify the juxtarenal landing zone of the endograft in 19/31 cases (61%) and the distal one in 31/31 (100%). In 12 (39%) cases, CO2 injection failed to visualize at least the lowest renal artery. This occurred in large aneurysms with scarce thrombotic apposition and a luminal volume greater than 95.9 (IQR: 25.2) mm3. Completion CO2 DSA detected type II endoleaks (ELIIs) in 10 cases compared with 2 of conventional contrast media. CONCLUSIONS: The injection of nontoxic CO2 through an automated device allowed to perform EVAR procedures effectively, in the majority of cases. In some cases, a single injection of a minimum amount of conventional contrast medium can be used to overcome the lack of renal artery visualization by CO2. ELIIs are more frequently visualized with CO2 compared with standard contrast medium. Although the CO2 injection technique needs further amelioration particularly in the renal arteries detection, this technique appears promising and possibly substitutive of the standard contrast medium, with significant benefit for the renal function.