Venous Signal Research Articles

Jugular venous reflux may mimic type I dural arterio-venous fistula on arterial spin labeling magnetic resonance images.

Previous studies have shown that arterial spin-labeling (ASL) has high sensitivity and specificity for detecting dural arteriovenous fistulas (DAVFs). However, in case of jugular venous reflux (JVR), the labeled protons in the jugular vein may lead to a venous hypersignal in the jugular vein, sigmoid, and transverse sinus on ASL images and mimic DAVF. To ascertain this hypothesis, two blinded senior neuroradiologists independently and retrospectively reviewed randomized ASL images and graded the likelihood of DAVF on a 5-point Likert scale in 2 groups of patients: (i) 13 patients with angiographically proven type I DAVF; and (ii) 11 patients with typical JVR diagnosed on the basis of clinical and MR imaging data, first using ASL alone, and second using ASL together with all of the sequences including 4D CE MRA. A dural venous ASL signal was seen in 11 patients with type I DAVF and in all the 11 patients with JVR, with no distinctive pattern between the two. The mean Likert score was "very likely" in DAVF and JVR patients when using ASL alone (k = 0.71), and "very unlikely" for JVR versus "very likely" for DAVF when using all the sequences available (k = 0.92). Our study shows that JVR can mimic DAVF on ASL images with potential implications for patient care. The detection of DAVFs should be based on additional MR sequences such as TOF-MRA and 4D CE MRA to exclude JVR and to avoid unnecessary DSAs.

Observational Study of Noninvasive Venous Waveform Analysis to Assess Intracardiac Filling Pressures During Right Heart Catheterization

BackgroundOutpatient monitoring and management of patients with heart failure (HF) reduces hospitalizations and health care costs. However, the availability of noninvasive approaches to assess congestion is limited. Noninvasive venous waveform analysis (NIVA) uses a unique physiologic signal, the morphology of the venous waveform, to assess intracardiac filling pressures. This study is a proof of concept analysis of the correlation between NIVA value and pulmonary capillary wedge pressure (PCWP) and the ability of the NIVA value to predict PCWP > 18 mmHg in subjects undergoing elective right heart catheterization (RHC). PCWP was also compared across common clinical correlates of congestion. Methods and ResultsA prototype NIVA device, which consists of a piezoelectric sensor placed over the skin on the volar aspect of the wrist, connected to a data-capture control box, was used to collect venous waveforms in 96 patients during RHC. PCWP was collected at end-expiration by an experienced cardiologist. The venous waveform signal was transformed to the frequency domain (Fourier transform), where a ratiometric algorithm of the frequencies of the pulse rate and its harmonics was used to derive a NIVA value. NIVA values were successfully captured in 83 of 96 enrolled patients. PCWP ranged from 4–40 mmHg with a median of 13 mmHg. NIVA values demonstrated a linear correlation with PCWP (r = 0.69, P < 0.05). ConclusionsThis observational proof-of-concept study using a prototype NIVA device demonstrates a moderate correlation between NIVA value and PCWP in patients undergoing RHC. NIVA, thus, represents a promising developing technology for noninvasive assessment of congestion in spontaneously breathing patients.

Validation of Zero TE-MRA in the Characterization of Cerebrovascular Diseases: A Feasibility Study.

Zero TE-MRA is less sensitive to field heterogeneity, complex flow, and acquisition noise. This study aimed to prospectively validate the feasibility of zero TE-MRA for cerebrovascular diseases assessment, compared with TOF-MRA. Seventy patients suspected of having cerebrovascular disorders were recruited. Sound levels were estimated for each MRA subjectively and objectively in different modes. MRA image quality was estimated by 2 neuroradiologists. The degree of stenosis (grades 0-4) and the z-diameter of aneurysms (tiny group ≤3 mm and large group >3 mm) were measured for further quantitative analysis. CTA was used as the criterion standard. Zero TE-MRA achieved significantly lower subjective perception and objective noise reduction (37.53%). Zero TE-MRA images showed higher signal homogeneity (3.29 ± 0.59 versus 3.04 ± 0.43) and quality of venous signal suppression (3.67 ± 0.47 versus 2.75 ± 0.46). The intermodality agreement was higher for zero TE-MRA than for TOF-MRA (zero TE, 0.90; TOF, 0.81) in the grading of stenosis. Zero TE-MRA had a higher correlation than TOF-MRA (zero TE, 0.84; TOF, 0.74) in the tiny group and a higher consistency with CTA (intraclass correlation coefficient, 0.83; intercept, -0.5084-1.1794; slope -0.4952 to -0.2093) than TOF-MRA (intraclass correlation coefficient, 0.64; intercept, 0.7000-2.6133; slope -1.0344 to -0.1923). Zero TE-MRA and TOF-MRA were comparable in the large group. Zero TE-MRA had more accurate details than TOF-MRA of AVM and Moyamoya lesions. Compared with TOF-MRA, zero TE-MRA achieved more robust performance in depicting cerebrovascular diseases. Therefore, zero TE-MRA was shown to be a promising MRA technique for further routine application in the clinic in patients with cerebrovascular diseases.

Signal Intensity within Cerebral Venous Sinuses on Synthetic MRI.

Purpose:Flowing blood sometimes appears bright on synthetic T1-weighted images, which could be misdiagnosed as a thrombus. This study aimed to investigate the frequency of hyperintensity within cerebral venous sinuses on synthetic MR images and to evaluate the influence of increasing flow rates on signal intensity using a flow phantom.Materials and Methods:Imaging data, including synthetic and conventional MRI scans, from 22 patients were retrospectively analyzed. Signal intensities at eight locations of cerebral venous sinuses on synthetic images were graded using the following three-point scale: 0, “dark vessel”; 1, “hyperintensity within the walls”; and 2, “hyperintensity within the lumen.” A phantom with gadolinium solution inside a U-shaped tube was acquired without flow and then with increasing flow rates (60, 100, 200, 300, 400 ml/min).Results:Considering all sinus locations, the venous signal intensity on synthetic T1-weighted images was graded as 2 in 79.8% of the patients. On synthetic T2-weighted images, all sinuses were graded as 0. On fluid-attenuated inversion recovery (FLAIR) images, sinuses were almost always graded as 0 (99.4%). In the phantom study, the signal initially became brighter on synthetic T1-weighted images as the flow rate increased. Above a certain flow rate, the signal started to decrease.Conclusion:High signal intensity within the cerebral venous sinuses is a frequent finding on synthetic T1-weighted images. This corresponds to the hyperintensity noted at certain flow rates in the phantom experiment.

Arterial-spin labeling MRI identifies residual cerebral arteriovenous malformation following stereotactic radiosurgery treatment

Background and purposeBrain arteriovenous malformation (AVM) treatment by stereotactic radiosurgery (SRS) is effective, but AVM obliteration following SRS may take two years or longer. MRI with arterial-spin labeling (ASL) may detect brain AVMs with high sensitivity. We determined whether brain MRI with ASL may accurately detect residual AVM following SRS treatment. Materials and methodsWe performed a retrospective cohort study of patients who underwent brain AVM evaluation by DSA between June 2010 and June 2015. Inclusion criteria were: (1) AVM treatment by SRS, (2) follow-up MRI with ASL at least 30 months after SRS, (3) DSA within 3 months of the follow-up MRI with ASL, and (4) no intervening AVM treatment between the MRI and DSA. Four neuroradiologists blindly and independently reviewed follow-up MRIs. Primary outcome measure was residual AVM indicated by abnormal venous ASL signal. Results15 patients (12 females, mean age 29 years) met inclusion criteria. There were three posterior fossa AVMs and 12 supratentorial AVMs. Spetzler–Martin (SM) Grades were: SM1 (8%), SM2 (33%), SM3 (17%), SM4 (25%), and SM5 (17%). DSA demonstrated residual AVM in 10 patients. The pooled sensitivity, specificity, positive predictive value, and negative predictive value of venous ASL signal for predicting residual AVM were 100% (95% CI: 0.9-1.0), 95% (95% CI: 0.7–1.0), 98% (95% CI: 0.9–1.0), and 100% (95% CI: 0.8–1.0), respectively. High inter-reader agreement as found by Fleiss’ Kappa analysis (k = 0.92; 95% CI: 0.8–1.0; P < 0.0001). ConclusionsASL is highly sensitive and specific in the detection of residual cerebral AVM following SRS treatment.

VSICON 2018 Prize Paper Abstracts

VSICON 2018 Prize Paper Abstracts

Subtractive non-contrast-enhanced MRI of lower limb veins using multiple flow-dependent preparation strategies.

To evaluate the performance of acceleration-dependent vascular anatomy for non-contrast-enhanced MR venography (ADVANCE-MRV) in femoral veins and to investigate whether venous signal uniformity can be improved by applying multiple acquisitions with different flow suppressions or multiple flow suppressions in 1 acquisition. The ADVANCE-MRV method uses flow-sensitized modules to acquire a dark-artery image set and a dark-artery vein set, which are subsequently subtracted. Ten healthy volunteers were imaged using the ADVANCE-MRV sequence with improved venous suppression uniformity in the dark-artery vein images achieved by applying multiple flow suppressions in the same acquisition or by combining multiple images acquired with different flow suppressions. The performance of the improved technique was also evaluated in 13 patients with lower-limb deep venous thrombosis. Multiple-preparation and multiple-acquisition approaches all improved venous signal uniformity and reduced the signal void artifacts observed in the original ADVANCE-MRV images. The multiple-acquisition approaches achieved excellent blood signal uniformity and intensity, albeit at the cost of an increase in the total acquisition time. The double-preparation approach demonstrated good performance in all measurements, providing a good compromise between signal uniformity and acquisition time. The blood signal spatial variation and its variation using different gradient amplitudes were reduced by 20% and 29%. All patient images showed uniform and bright venous signal in nonoccluded sections of vein. The enhanced ADVANCE-MRV methods substantially improved signal uniformity in healthy volunteers and patients with known deep venous thrombosis. The double-preparation approach gave good-quality femoral vein images, providing improved venous signal uniformity without increasing acquisition time in comparison to the original sequence.

Improved visualization of superficial temporal artery using segmentedtime-of-flight MR angiography with venous suppression at 7T.

To evaluate the quality of time-of-flight MR angiography (TOF-MRA) with venous suppression at 7T on imaging superficial temporal artery (STA). A recently developed segmented TOF technique with reduced specific absorption rate (SAR) of venous suppression (VS) module was employed to achieve high-resolution arterial angiography without the contamination of venous signal. Images of segmented TOF with VS at 7T, TOF without VS at 7T, and TOF with VS at 3T were collected on 17 healthy volunteers. The number of STA branches and their local contrast achieved by the three methods were quantified and compared using paired t test. Segmented TOF with VS at 7T successfully suppressed venous signal without reducing the contrast of arterial angiography. The numbers of STA branches in 7T images were significantly higher than that in 3T images (5.79 vs. 4.50, p < 0.001). The contrast of 7T segmented TOF was significantly higher than 3T TOF (7.21 vs. 5.56, p = 0.006). Segmented TOF with VS at 7T displayed more branches of STA, while eliminating the signal of superficial temporal vein (STV). The improved visualization of STA will potentially facilitate the pre-operative assessment of STA in STA-MCA bypass surgery.

The Role of Susceptibility Weighted Imaging (SWI) in Evaluation of Acute Stroke

Background and Objectives: SWI provides information about blood oxygenation levels in intracranial vessels. Prior reports have shown that SWI focusing on venous drainage can provide noninvasive information about the degree of brain perfusion in arterialischemic stroke. We aimed to evaluate the influence of the SWI venous signal pattern in predicting stroke evolution. Materials and Methods: a semiquantitative analysis of venous signal intensity on SWI and diffusion characteristics on DTI was performed in 2o adult patients with acute stroke of MCA vascular territories. The mismatch between areas with SWI-hypointense venous signal and restricted diffusion was correlated with stroke progression on follow-up. Results: we included 2O patients with a confirmed diagnosis of arterial ischemic stroke. Follow-up images were available for. MCA stroke progression on follow-up was observed in 11/12 patient with DWI -SWI mismatch. Initial SWI hypointense venous signal and areas of restricted diffusion on DTI. This mismatch showed a statistically significant association (P _ 0.00188) for infarct progression. Conclusion: SWI-DWI mismatch predicts stroke progression in arterial ischemic stroke.

The Role of Susceptibility Weighted Imaging (SWI) in Evaluation of Acute Stroke

Background and Objectives: SWI provides information about blood oxygenation levels in intracranial vessels. Prior reports have shown that SWI focusing on venous drainage can provide noninvasive information about the degree of brain perfusion in arterialischemic stroke. We aimed to evaluate the influence of the SWI venous signal pattern in predicting stroke evolution. Materials and Methods: a semiquantitative analysis of venous signal intensity on SWI and diffusion characteristics on DTI was performed in 2o adult patients with acute stroke of MCA vascular territories. The mismatch between areas with SWI-hypointense venous signal and restricted diffusion was correlated with stroke progression on follow-up. Results: we included 2O patients with a confirmed diagnosis of arterial ischemic stroke. Follow-up images were available for. MCA stroke progression on follow-up was observed in 11/12 patient with DWI -SWI mismatch. Initial SWI hypointense venous signal and areas of restricted diffusion on DTI. This mismatch showed a statistically significant association (P _ 0.00188) for infarct progression. Conclusion: SWI-DWI mismatch predicts stroke progression in arterial ischemic stroke.

Arterial Spin-Labeling Improves Detection of Intracranial Dural Arteriovenous Fistulas with MRI.

Intracranial dural arteriovenous fistulas carry a risk of substantial neurologic complications but can be difficult to detect on structural MR imaging and TOF-MRA. The purpose of this study was to assess the accuracy and added value of 3D pseudocontinuous arterial spin-labeling MR imaging for the detection of these lesions. This retrospective study included 39 patients with a dural arteriovenous fistula and 117 controls who had undergone both DSA and MR imaging with pseudocontinuous arterial spin-labeling. Two neuroradiologists blinded to the DSA results independently assessed MR imaging with and without pseudocontinuous arterial spin-labeling. They recorded specific signs, including venous arterial spin-labeling signal, and the likelihood of a dural arteriovenous fistula using a 5-point Likert scale. Logistic regression and receiver operating characteristic analyses were performed to determine the accuracy of specific signs and the added value of pseudocontinuous arterial spin-labeling. Interobserver agreement was determined by using κ statistics. Identification of the venous arterial spin-labeling signal had a high sensitivity (94%) and specificity (88%) for the presence a dural arteriovenous fistula. Receiver operating characteristic analysis showed significant improvement in diagnostic performance with the addition of pseudocontinuous arterial spin-labeling in comparison with structural MR imaging (Δarea under the receiver operating characteristic curve = 0.179) and a trend toward significant improvement in comparison with structural MR imaging with time-of-flight MRA (Δarea under the receiver operating characteristic curve = 0.043). Interobserver agreement for the presence of a dural arteriovenous fistula improved substantially and was almost perfect with the addition of pseudocontinuous arterial spin-labeling (κ = 0.92). Venous arterial spin-labeling signal has high sensitivity and specificity for the presence of a dural arteriovenous fistula, and the addition of pseudocontinuous arterial spin-labeling increases confidence in the diagnosis of this entity on MR imaging.

Venous ultrasonography findings and clinical correlations in 104 Thai patients with chronic venous insufficiency of the legs

The pattern of venous reflux in Thai patients with chronic venous insufficiency (CVI) was studied in correlation with clinical manifestations. Ultrasonography findings and clinical data were prospectively collected and retrospectively reviewed. CVI was found in 104 legs of 79 patients (mean age 59.8 ± 12.5 years; C4: 24.1%, C5: 8.9%, C6: 67.1%). 6.7% of the legs had a history of deep vein thrombosis (DVT). The prevalence of superficial vein reflux (SVR), deep vein reflux (DVR), and combined SVR and DVR in 90 legs without previous venous surgery was 82.2%, 63.3% and 57.8%, respectively. In legs with SVR, the prevalence of great saphenous vein reflux (GSVR), small saphenous vein reflux (SSVR), and combined GSVR and SSVR was 91.9%, 33.8% and 25.7%, respectively. 77.0% of SVR involved the calf segment. For medial ulceration, 79.6% had GSVR and 35.2% had SSVR. For lateral ulceration, 46.7% had SSVR and 33.3% had isolated GSVR. Pulsatile venous signal was found in 3.3% of legs. In 17 legs with ulceration after previous surgical treatment, calf vein reflux (residual calf great saphenous vein or small saphenous vein) was found in 13 (76.5%) legs. Calf vein reflux plays an important role in CVI and in patients with recurrent ulceration after previous superficial venous surgery. Although GSVR was present in most patients with CVI in the legs, SSVR may present in one-third of patients, especially those with lateral ulceration. The high prevalence of DVR in the absence of DVT and the presence of a pulsatile venous signal in some patients highlight the incomplete understanding of CVI aetiology.

Preliminary evidence for cerebral capillary shunting in adults with sickle cell anemia

Elevated flow velocities in adults with sickle cell anemia (SCA) may cause rapid erythrocyte transit through capillaries. This phenomenon could present as dural venous sinus hyperintensity on arterial spin labeling (ASL)-MRI and could be indicative of capillary shunting. Here, the prevalence of ASL venous hyperintensities and association with relevant physiology in adults with SCA was investigated. SCA (n = 46) and age-matched control (n = 16) volunteers were recruited for 3.0 T MRI. Pseudo-continuous ASL-MRI was acquired for cerebral blood flow (CBF) calculation and venous hyperintensity determination; venous signal intensity and a categorical venous score (three raters; 0 = no hyperintensity, 1 = focal hyperintensity, and 2 = diffuse hyperintensity) were recorded. Flow velocity in cervical internal carotid artery segments was determined from phase contrast data (venc = 40 cm/s) and whole-brain oxygen extraction fraction (OEF) was determined from T2-relaxation-under-spin-tagging MRI. Cerebral metabolic rate of oxygen was calculated as the product of OEF, CBF, and blood oxygen content. ASL venous hyperintensities were significantly (p < 0.001) more prevalent in SCA (65%) relative to control (6%) participants and were associated with elevated flow velocities (p = 0.03). CBF (p < 0.001), but not OEF, increased with increasing hyperintensity score. Prospective trials that evaluate this construct as a possible marker of impaired oxygen delivery and stroke risk may be warranted.

Endoscopic Doppler Probe in the Diagnosis and Management of Upper Gastrointestinal Hemorrhage

Through-the-Scope (TTS) endoscopic Doppler ultrasound probe technology is a tool that has garnered interest for the evaluation of variceal and non-variceal bleeding. We describe two cases in which endoscopic Doppler probe guided diagnosis and management of two patients with upper gastrointestinal hemorrhage. A 55 year old African American male with history of nephrectomy for a T1N0M0 renal cell carcinoma,end stage renal disease on hemodialysis presented to the emergency department after an episode of melena.Hemoglobin on presentation was 7.1 g/dl. During the hospitalization,he underwent several endoscopies and tagged RBC scan, none of which could identify a source of bleeding.EUS was performed to assess the gastric fundus for gastric varices or gastric Dieulafoy, which was unremarkable.Endoscopy with Doppler probe was subsequently performed and identified a 2 mm. red spot in the duodenal bulb with strong arterial signal compatible with a duodenal Dieulafoy lesion,which was successfully treated.The patient did not have further episodes of bleeding and hemoglobin stabilized at 8 g/dl. A 32 year old male with recent history of binge drinking and emesis presented with gastrointestinal bleeding.On arrival, the patient was hemodynamically stable.Laboratory values were significant for hemoglobin of 13.5 g/dl and platelets of 88 x109/L.On initial endoscopic evaluation, a Mallory-Weiss tear was seen and thought to be the etiology of bleeding.Further evaluation with endoscopic Doppler US probe revealed an audible venous Doppler signal that was consistent with a varix, and closer endoscopic inspection revealed a junctional gastroesophageal varix with a tear.Three bands were successfully placed and post-band ligation Doppler signal was absent. In summary, we present two patients in whom a TTS endoscopic Doppler ultrasound probe guided the diagnosis and subsequent management of acute upper gastrointestinal hemorrhage.In the first patient,it helped to identify an obscure source of GI bleeding after multiple endoscopies and a bleeding scan.In the second patient,it served to discover an unsuspected bleeding etiology of a junctional varix when a Mallory-Weiss tear was initially suspected which then resulted in change of clinical management.Though the literature has identified its utility in peptic ulcer hemorrhage,these cases highlight its use in other causes,which may translate to downstream effects, such as decreasing morbidity and mortality related to GI hemorrhage.Figure: Case One: Two mm red spot in duodenal bulb (arrow), seen during repeat EGD on day 6.Figure: Case Two: Initial endoscopy showing a tear around GE junction (arrow), thought to represent Mallory- Weiss tear.Figure: Case Two: Junctional varix post-band ligation.

Time-of-flight MR angiography in cerebral venous sinus thrombosis.

Recently, time-of-flight (TOF) and gadolinium-enhanced MR angiography (MRA) imaging have been used to demonstrate subacute intramural hematoma in cervical artery dissection and to detect intraplaque haemorrhage. Our aim was to perform an exploratory study to analyse if venous thrombus-related signal changes (potentially showing iso- or hyperintensity) in cerebral venous sinus thrombosis (CVST) could be observed on 3D-TOF MRA imaging. We analysed retrospectively MRIs of CVST patients in whom both contrast-enhanced MR venography (CEMRV) and 3D-TOF sequences were performed in the acute/subacute phase (i.e. <31days after symptom onset). The occluded sinus segments were defined on CEMRV. First, analyses of signal changes in occluded venous sinuses segments (defined by and unblinded to CEMRV) on native 3D-TOF images and morphological MRI sequences were performed. Second, a blinded (to CEMRV and other morphological MRI sequences) analysis was performed on 3D-TOF imaging assessing signal changes on 3D-TOF considering all sinus segments. Twenty-five CVST patients were included. 3D-TOF imaging showed signal changes (most often hyperintensity and less often isointensity) in 84% of the occluded sinus segments. Signal changes were observed in 91% of the occluded sinus segments on T1-weighted imaging, in 69% on T2-weighted imaging, in 68% on FLAIR, in 32% on DWI, and in 55% on T2*-weighted imaging. On blinded analysis, sensitivity of 3D-TOF sequences decreased to 80%, whereas specificity was only 65%. Abnormal signal in the venous sinuses on 3D-TOF may possibly help to suspect CVST, especially when CEMRV sequences lack.

Echo-time dependence of the BOLD response transients – A window into brain functional physiology

The blood oxygenation level-dependent (BOLD) fMRI response to neuronal activation results from a complex interplay of induced metabolic and vascular changes. Thus, its transients, such as initial overshoot and post-stimulus undershoot, provide a window into the dynamic relationships of the underlying physiological variables. In this study, we propose multi-echo fMRI as a tool to investigate the physiological underpinnings of the BOLD signal, in particular, and brain functional physiology, in general. In the human visual cortex at 3 T, we observed that the BOLD response is nonlinearly dependent on echo-time (TE) and the amount of nonlinearity varies during the entire time-course. Fitting a linear model to this nonlinear relationship resulted in a positive intercept at TE = 0 ms. The time-course of the intercept exhibited fast and slow modulations, distinctly different both from the BOLD response and cerebral blood flow (CBF). In order to shed light on the TE-dependence of the BOLD signal and the intercept time-course, we performed simulations based on a nonlinear two-compartmental BOLD signal model combined with the dynamic balloon model. The modeling suggests that the intercept time-course reflects a weighted sum of deoxyhemoglobin concentration and venous CBV signal changes. We demonstrate that only CBF-venous blood volume (CBV) uncoupling but not CBF-oxygen metabolism (CMRO2) uncoupling can fully account for our experimental observations. In particular, these results strongly argue for a slow evolution of the venous CBV together with stimulus-type-dependent CBF transients (the latter being tightly coupled with CMRO2) to be responsible for the BOLD signal adaptation during stimulation and for the post-stimulus undershoot. Thus, BOLD signal transients are composed of smoothed version of neuronal time-course as reflected in CBF and CMRO2 and secondary vascular processes due to biomechanics of venous blood vessels, and multi-echo fMRI in combination with modeling provides invaluable insights into these physiological processes.

Cortical venous disease severity in MELAS syndrome correlates with brain lesion development.

MELAS syndrome is a mitochondrial disorder typified by recurrent stroke-like episodes, seizures, and progressive brain injury. Abnormal mitochondria have been found in arterial walls implicating a vasculogenic etiology. We have observed abnormal cortical vein T2/FLAIR signal in MELAS patients, potentially representing wall thickening and sluggish flow. We sought to examine the relationship of hyperintense veins and brain lesions in MELAS. Imaging databases at two children's hospitals were searched for brain MRIs from MELAS patients. Artifact, sedated exams, and lack of 2D-T2/FLAIR sequences were exclusion criteria. Each exam was assigned a venous score based on number of T2/FLAIR hyperintense veins: 1=<10, 2=10 to 20, 3=>20. Cumulative brain lesions and venous score in MELAS and aged-matched normal exams were compared by Mann-Whitney test. A total of 106 exams from 14 unique MELAS patients (mean 16±3years) and 30 exams from normal aged-matched patients (mean 15±3years) were evaluated. Median venous score between MELAS and control patients significantly differed (3 versus 1; p<0.001). In the MELAS group, venous score correlated with presence (median=3) or absence (median=1) of cumulative brain lesions. In all 8 MELAS patients who developed lesions, venous hyperintensity was present prior to, during, and after lesion onset. Venous score did not correlate with brain lesion acuity. Abnormal venous signal correlates with cumulative brain lesion severity in MELAS syndrome. Cortical venous stenosis, congestion, and venous ischemia may be mechanisms of brain injury. Identification of cortical venous pathology may aid in diagnosis and could be predictive of lesion development.

Non‐contrast‐enhanced peripheral MR angiography using velocity‐selective excitation

To develop a new non-contrast-enhanced peripheral MR angiography that provides a high contrast angiogram without using electrocardiography triggering and saturation radiofrequency pulses. A velocity-selective excitation technique is used in conjunction with the golden-angle radial sampling scheme. The signal amplitude varies according to the velocity of the flow by the velocity-selective excitation technique. Because the arterial blood velocity varies depending on the cardiac phase, the acquired data can be classified into systolic and diastolic phase based on the signal amplitude of the artery. Two images are then reconstructed from the systolic and diastolic phase data, respectively, and an image reflecting the differences between the two images is obtained to eliminate background and vein signals. The performance of the proposed method was compared with the quiescent-interval single shot (QISS) in eight healthy subjects and an elderly subject. The proposed method generated fewer residual venous and background signals than the QISS. Furthermore, the maximum intensity projection images, the relative contrast, and the apparent contrast-to-noise ratio results showed that the proposed method produced a better contrast than the QISS. The proposed non-contrast-enhanced peripheral MR angiography technique can provide a high contrast angiogram without the use of electrocardiography triggering and saturation radiofrequency pulses. Magn Reson Med 79:779-788, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Cardioprotective Effects of Carvedilol in Inhibiting Doxorubicin-induced Cardiotoxicity.

Anthracyclines (ANTs) are a class of active antineoplastic agents with topoisomerase-interacting activity that are considered the most active agents for the treatment of breast cancer. We investigated the efficacy of carvedilol in the inhibition of ANT-induced cardiotoxicity. In this randomized, single-blind, placebo-controlled study, 91 women with recently diagnosed breast cancer undergoing ANT therapy were randomly assigned to groups treated with either carvedilol (n = 46) or placebo (n = 45). Echocardiography was performed before and at 6 months after randomization, and absolute changes in the mean left ventricular ejection fraction, left ventricular end diastolic volume, and left ventricular end systolic volume were determined. Furthermore, the percentage change in the left atrial (LA) diameter and other variables of left ventricular (LV) diastolic function, such as transmitral Doppler parameters, including early (E wave) and late (A wave) diastolic velocities, E/A ratio and E wave deceleration time, pulmonary venous Doppler signals, including forward systolic (S wave) and diastolic (D wave) velocities into LA, late diastolic atrial reversal velocity, and early diastolic tissue Doppler mitral annular velocity (e') were measured. In addition, tissue Doppler mitral annular systolic (s') velocity, as a marker of early stage of LV systolic dysfunction, E/e' ratio, as a determinant of LV filling pressure, and troponin I level, as a marker of myocardial necrosis were measured. At the end of follow-up period, left ventricular ejection fraction did not change in the carvedilol group. However, this parameter was significantly reduced in the control group (P < 0.001). Echocardiography showed that both left ventricular end systolic volume and LA diameter were significantly increased compared with the baseline measures in the control group. In pulse Doppler studies, pulmonary venous peak atrial reversal flow velocity was significantly increased in the control group. Moreover, a significant decrease in the mitral annuli early diastolic (e') and peak systolic (s') velocities and a significant increase in the E (the peak early diastolic velocity)/e' ratio in the control group were also observed. However, none of these variables were adversely changed at the end of follow-up in the carvedilol group. Furthermore, the TnI level was significantly higher in the control group than in the carvedilol group (P = 0.036) at 30 days after the initiation of chemotherapy. Prophylactic use of carvedilol may inhibit the development of anthracycline-induced cardiotoxicity, even at low doses.

Abstract 529: Statin Therapy Decreases Vascular Inflammation and Prolongs Patency in Murine Arteriovenous Fistula

Background: AVFs are the lifeline of dialysis patients, but can often occlude. The most common cause of AVF failure is inflammation-driven neointimal hyperplasia and thrombosis. Here, we investigated whether statin therapy with well-recognized anti-inflammatory properties can improve murine AVF patency, and further assessed the anti-inflammatory effects. Methods: One week prior to AVF creation, mice were randomized to oral atorvastatin 1.14mg/kg/day or control 100ul PBS (both n=10), administered by daily gavage. AVF were created using an end-to-side internal jugular vein and carotid artery anastomosis. AVF blood flow was measured (Transonic blood flow probe) at day 0 and weekly thereafter until occlusion (blood flow &lt; 0.1ml/min). On day 6, CLIO-VT680, an inflammatory cell-targeted fluorescent nanoparticle, was injected intravenously (10mg/kg). 24 hours later, in vivo survival epifluorescence molecular imaging was performed to visualize inflammatory cell in the AVF venous outflow limb. Histopathological assessment of AVF was performed in on day 7 and 14 mice (6 statin each, 6 control each) to assess venous outflow area, AVF scarring via collagen, and adventitial macrophage content. Results: At day 7, the in vivo venous outflow cellular inflammation signal (CLIO-VT680 TBR) was significantly lower in statin-treated mice (3.5±0.16 vs 4.5±0.5 PBS, p=0.02). Adventitial macrophage content was significantly lower in statin group at day 14 (p=0.01). Positive AVF remodeling, a desirable feature for clinical AVF patency, was higher in the statin group as compared to the PBS group (p=0.02 at week 1, p=0.002 at week 2). In vivo, statin-treated animals exhibited greater AVF blood flow (BF) preservation from day 7 to day 14 (ΔAVF BF +0.14±0.2 ml/min vs. -0.79±0.32 ml/min PBS, p=0.02). The ΔAVF BF from day 7 to day 14 correlated inversely and significantly with the day 7 CLIO-VT680 cellular inflammation (r=-0.56, p=0.02), indicating that baseline inflammation may predict AVF failure. Kaplan Meier survival analysis showed median AVF patency in mice treated with statin was 28 days compared to 14 days in PBS treated group (p&lt;0.05). Conclusion: Statin therapy prolongs AVF patency and preserves AVF blood flow in association with diminished AVF cellular inflammation.