Arteriovenous Transit Time Research Articles

Optic disc hemorrhage is related to various hemodynamic findings by disc angiography.

BackgroundTo investigate the hemodynamic characteristics of glaucoma eyes with disc hemorrhage (DH) by disc fluorescein angiography, and its relationship with glaucomatous changes of the optic disc and surrounding retinal nerve fiber layer (RNFL).MethodsThis study included 35 glaucoma eyes with DH who were followed up at least 5 years and had DH at presentation. Eyes were classified as eyes with DH at the border of localized RNFL defects and eyes with DH not related to localized RNFL defects. Prevalence of DH and location of the proximal border were recorded from disc photographs. Fluorescein angiography was performed 3 months after detecting the DH. Arm-retina time, arteriovenous transit time, disc filling time, choroidal filling time, and venous filling time were measured as retinal circulation parameters. The presence of disc filling defects and disc leaks were evaluated.ResultsThere were 19 (54.3%) eyes with DH accompanying localized RNFL defects. The arm-retina time was prolonged in eyes with DH not related to RNFL defects (P = 0.044) and the arteriovenous transit time was prolonged in eyes with DH accompanying RNFL defects (P = 0.029). Among eyes with DH accompanying RNFL defects, 11 (57.9%) had vessel filling defects or delayed filling indicating blood flow stasis at the cup margin proximal to where DH occurred. Eyes with DH not related to RNFL defects did not show vessel filling defects or delayed filling.Conclusions and RelevanceEyes with DH related to RNFL defects showed prolonged arteriovenous transit time and had frequent vessel filling defects or delayed filling indicating blood flow stasis and thrombus formation at the site DH occurred. These findings suggest that vascular and hemodynamic changes due to glaucomatous structural changes cause DH in relation to localized RNFL defects.

A Case of Multiple Complications in Herpes Zoster Ophthalmicus

Purpose: We report a case of stromal keratitis, corneal infiltration, anterior uveitis, central retinal artery occlusion and optic neuropathy in a patient with herpes zoster ophthalmicus. Case summary: A 73-year-old man who was hospitalized for pain and vesicles on his left face was referred to our clinic with sudden onset visual disturbance in his left eye. His best corrected visual acuity in the right eye was 0.8 and light-perception in his left eye. Relative afferent pupillary defect was found in his left eye. Slit-lamp examination showed anterior uveitis secondary to herpes zoster ophthalmicus presented with stromal keratitis. Fundus examination showed retinal hemorrhage, vitreous opacity, cherry-red spot in the fovea and optic disc swelling. Delayed arterial filling and arteriovenous transit time were observed on fluorescence angiography. He was treated with topical antiviral and steroid eye drops for stromal keratitis and anterior uveitis. He was also treated systemically with an intravenous antiviral agent and oral steroid, but visual acuity did not improve. Conclusions: Stromal keratitis, corneal opacity, anterior uveitis, central retinal artery occlusion and optic neuropathy can be complications of herpes zoster ophthalmicus. J Korean Ophthalmol Soc 2015;56(5):789-793

Contrast-Enhanced Ultrasound Identifies Reduced Overall and Regional Renal Perfusion During Global Hypoxia in Piglets

It is well known from both clinical experience and animal research that renal hypoxia may lead to temporary or permanent renal failure, the severity being dependent largely on the duration and grade of the hypoxia. The medulla is more susceptible to hypoxic injury than the cortex because approximately 90% of the renal blood flow supplies the cortex. Various methods have been applied to evaluate renal perfusion in both experimental and clinical settings, including magnetic resonance imaging, computed tomography, laser Doppler, and contrast-enhanced ultrasound (CEUS). The aim of this study was to evaluate changes in overall and regional renal perfusion with CEUS in response to global hypoxia. Twelve newborn anesthetized piglets were exposed to general hypoxia with a fraction of inspired oxygen of 8% of 30 minutes duration. Resuscitation was performed with either 100% oxygen (n = 6) or air (21% oxygen) (n = 6) for 30 minutes followed by 7 hours of reoxygenation with air. Before, during, and after hypoxia, the left kidney was examined with CEUS using 0.2 mL IV of SonoVue followed by 2 mL saline flush. Five additional piglets served as controls. The kidney was examined using a 9-MHz linear transducer with low mechanical index (0.21) and pulse inversion contrast program. One region of interest was drawn in the renal cortex and 1 in the medulla to obtain the corresponding time intensity curves (TICs). From these curves, the peak intensity (PI), time to peak (TTP), upslope of the curve, area under the curve, and mean transit time (MTT) were recorded. Also, the renal arteriovenous transit time (AVTT) was registered. The resistance index (RI) was repeatedly measured in the renal artery. Contrast-enhanced ultrasound was repeated at regular intervals until the animals were sacrificed 8 hours after the hypoxic period. In the group of 12 piglets subjected to hypoxia, RI increased from 0.69 ± 0.08 at baseline to 0.99 ± 0.09 during hypoxia (P < 0.01), indicating severe general renal vasoconstriction. The AVTT increased from 2.6 ± 0.5 seconds at baseline to 6.7 ± 2.8 seconds during hypoxia (P < 0.001). The PI in the cortex decreased from a mean value of 38.6 ± 6.1 dB at baseline to 30.3 ± 9.7 dB during hypoxia (P < 0.05). In the medulla, only a minor, nonsignificant reduction in PI was observed during hypoxia. In the medulla, TTP and MTT increased from 6.4 ± 1.5 and 9.2 ± 1.7 seconds at baseline to 14.6 ± 8.4 seconds (P < 0.01) and 15.2 ± 5.6 seconds (P < 0.01), respectively, during hypoxia. In the cortex, no statistically significant changes in TTP or MTT were observed during hypoxia. A return to near-baseline values was observed for TTP, PI in both the medulla and cortex, as well as for RI and AVTT within 1 to 3 hours after hypoxia, and they remained relatively constant for the duration of the experiment.Less than 1 hour after the hypoxia, PI both in the cortex and the medulla was significantly higher in the group resuscitated with air than in the group resuscitated with 100% oxygen, 36.0 ± 4.3 versus 27.2 ± 2.2 dB (P < 0.05) and 33.3 ± 8.2 versus 21.1 ± 2.0 dB (P < 0.01), respectively. Global hypoxia induced changes in overall and regional renal perfusion detectable with CEUS. Cortical and medullary flows were affected differently by hypoxia; a strong increase in medullary TTP and MTT was observed, indicating a reduction in medullary blood flow velocity. In the cortex, a significant reduction in PI was found, probably because of a reduction in cortical blood volume. A faster recovery of both medullary and cortical PI in the group resuscitated with air could indicate that air might be more beneficial for renal perfusion than hyperoxia during resuscitation after renal hypoxia.

Abstract 158: Magnetic Resonance Digital Subtraction Angiography Identifies Impaired Drainage in Arteriovenous Malformations With History of Rupture

BACKGROUND: Cerebral digital subtraction angiography (DSA) has established impaired hemodynamic drainage of intracranial arteriovenous malformations (iAVM) as a risk factor for iAVM hemorrhage. Unlike conventional DSA, MR-DSA offers a noninvasive means of characterizing iAVM hemodynamics. We hypothesize that MR-DSA will demonstrate impaired drainage in iAVMs with history of rupture when compared to iAVMs without history of rupture. METHODS: Consecutive patients with untreated, DSA-confirmed iAVM underwent MR-DSA on a 3T Whole-body MR-scanner. For each iAVM, regions of interest (ROI) were drawn on all feeder arteries and draining veins. Time-density curves were constructed for each ROI. The arteriovenous malformation transit time (ATT) was defined for each ROI as the time between contrast arrival and peak intravascular contrast density on the MR time-density curve. The drainage of each iAVM was characterized by the ratio of the draining vein ATT to the mean feeder artery ATT. The ATT ratio was compared between iAVMs with history of hemorrhage and those without. Statistical analysis was performed using a Student’s unpaired t-test with p &lt;0.05 defined as statistically significant. RESULTS: From May 2011 to April 2012, 13 patients (7M:6F, 40.6±13.8 years old) were enrolled in our study, with 3 patients presenting with history of hemorrhage and the remainder presenting with history of seizure, focal neurological deficit, headache, or as an incidental finding. The ATT ratio was significantly higher in iAVMs with history of hemorrhage than in those without (1.17±0.06 vs 0.95±0.02, p &lt;2.9E-7). CONCLUSION: MR-DSA identifies impaired drainage in iAVMs with history of rupture without exposing patients to the procedural risks and ionizing radiation associated with cerebral DSA. FIGURE A: MR-DSA with feeder artery (red) and draining vein (yellow) labeled. FIGURE B: Time-density curves of the artery (red) and vein (yellow) from which vessel ATTs were derived.

Treatment of Acute Central Retinal Artery Occlusion with Ocular Ischemic Syndrome

Purpose: We report a case of treatment of acute central retinal artery occlusion (CRAO) with ocular ischemic syndrome (OIS). Case summary: A 72-year-old man presented with acute loss of vision in the right eye on that day. At initial examination, visual acuity tested positive for light sensitivity in the right eye. Fundus examination demonstrated a visible embolus at the central retinal artery overlying the optic disc head and a cherry-red spot in the fovea. Fluorescein angiography revealed that filling of the choroidal circulation was delayed, and the arteriovenous transit time was even further delayed. Carotid angiography showed marked stenosis within the right internal carotid artery. Laboratory tests included blood tests for hypercoagulability evaluation, for which the results were non-specific. To treat acute CRAO with OIS in the right eye, transluminal Nd:YAG laser embolectomy (TYE) was performed twice, and carotid angioplasty with stenting was conducted within the stenosed internal carotid artery. One month after the TYE procedure and carotid stenting, the patient’s visual acuity improved to 0.06 and the arteriovenous transit time was within normal limits on fluorescein angiography. Conclusions: The visual prognosis in eyes with CRAO plus an associated choroidal circulatory disturbance is extremely poor. However, we experienced and reported a case of CRAO with OIS treated successfully through a prompt TYE procedure and carotid angioplasty with stenting. J Korean Ophthalmol Soc 2014;55(8):1242-1247

Clinical values of intraoperative indocyanine green fluorescence video angiography with Flow 800 software in cerebrovascular surgery

Background Microscope-integrated near-infrared indocyanine green video angiography (ICG-VA) has been used in neurosurgery for a decade. This study aimed to assess the value of intraoperative indocyanine green (ICG) video angiography with Flow 800 software in cerebrovascular surgery and to discover its hemodynamic features and changes of cerebrovascular diseases during surgery. Methods A total of 87 patients who received ICG-VA during various surgical procedures were enrolled in this study. Among them, 45 cases were cerebral aneurysms, 25 were cerebral arteriovenous malformations (AVMs), and 17 were moyamoya disease (MMD). A surgical microscope integrating an infrared fluorescence module was used to confirm the residual aneurysms and blocking of perforating arteries in aneurysms. Feeder arteries, draining veins, and normal cortical vessels were identified by the time delay color mode of Flow 800 software. Hemodynamic parameters were recorded. All data were analyzed by SPSS version 18.0 (SPSS Inc., USA). T-test was used to analyze the hemodynamic features of AVMs and MMDs, the influence on peripheral cortex after resection in AVMs, and superficial temporal artery to middle cerebral artery (STA-MCA) bypass in MMDs. Results The visual delay map obtained by Flow 800 software had more advantages than the traditional playback mode in identifying the feeder arteries, draining veins, and their relations to normal cortex vessels. The maximum fluorescence intensity (MFI) and the slope of ICG fluorescence curve of feeder arteries and draining veins were higher than normal peripheral vessels (MFI: 584.24±85.86 vs. 382.94±91.50, slope: 144.95±38.08 vs. 69.20±13.08, P &lt;0.05). The arteriovenous transit time in AVM was significantly shorter than in normal cortical vessels ((0.60±0.27) vs. (2.08±1.42) seconds, P &lt;0.05). After resection of AVM, the slope of artery in the cortex increased, which reflected the increased cerebral flow. In patients with MMD, after STA-MCA bypass, cortex perfusion of corresponding branches region increased and local cycle time became shorter. Conclusion Intraoperative ICG video angiography combined with hemodynamic parameter analysis obtained by Flow 800 software appears to be useful for intraoperative monitoring of regional cerebral blood flow in cerebrovascular disease.

THE RELATIONSHIP BETWEEN FUNDUS FLUORESCEIN ANGIOGRAPHIC FINDINGS AND SEROUS MACULAR DETACHMENT IN DIABETIC MACULAR EDEMA

To investigate whether the serous macular detachment (SMD) shown by optical coherence tomography is associated with types of maculopathy, severity of retinopathy, the effect of macular and retinal photocoagulation, and retinal circulation times in diabetic macular edema. Patients were grouped as SMD+ (Group 1) and SMD- (Group 2). Fundus photography and fluorescein angiography were evaluated regarding the type of maculopathy; severity of retinopathy and also arm-retina time, arteriovenous transit time, and venous filling time; and the applied macular and panretinal laser treatment. Diffuse maculopathy was seen more frequently in eyes with SMD, whereas ischemic maculopathy was more frequent in eyes without SMD. There was no significant difference regarding severity of retinopathy and retinal circulation times between groups. The frequency of patients with complete panretinal photocoagulation and grid laser photocoagulation was found to be higher in Group 2. Serous macular detachment can occur in eyes with increased vascular permeability in macula. Serous macular detachment may be an important finding in terms of the possible existence of diffuse maculopathy and the need of additional panretinal photocoagulation, but absence of SMD may point at ischemic maculopathy.

Fundus Fluorescein Angiographic Findings in Patients Who Underwent Ventricular Assist Device Implantation

Disruption of microcirculation in various tissues as a result of deformed blood rheology due to ventricular assist device (VAD) implantation causes novel arteriovenous malformations. Capillary disturbances and related vascular leakage in the retina and choroidea may also be seen in patients supported by VADs. We aimed to evaluate retinal vasculature deteriorations after VAD implantation. The charts of 17 patients who underwent VAD implantation surgery for the treatment of end-stage heart failure were retrospectively reviewed. Eight cases (47.1%) underwent pulsatile pump implantation (Berlin Heart EXCOR, Berlin Heart Mediprodukt GmbH, Berlin, Germany); however, nine cases (52.9%) had continuous-flow pump using centrifugal design (HeartWare, HeartWare Inc., Miramar, FL, USA). Study participants were selected among the patients who had survived with a VAD for at least 6 months, and results of detailed ophthalmologic examinations including optic coherence tomography (OCT) and fundus fluorescein angiography (FA) were documented. All of the 17 patients were male, with a mean age of 48.5 ± 14.8 years (15-67 years). Detailed ophthalmologic examinations including the evaluation of retinal vascular deteriorations via FA were performed at a mean of 11.8 ± 3.7 months of follow-up (6-18 months). Mean best-corrected visual acuity and intraocular pressure were found as logMAR 0.02 ± 0.08 and 14.6 ± 1.9 mm Hg, respectively in the study population. Dilated fundoscopy revealed severe focal arteriolar narrowing in two patients (11.8%), and arteriovenous crossing changes in four patients (23.5%); however, no pathological alteration was present in macular OCT scans. In patients with continuous-flow blood pumps, mean arm-retina circulation time (ARCT) and arteriovenous transit time (AVTT) were found to be 16.8 ± 3.0 and 12.4 ± 6.2 s, respectively; whereas those with pulsatile-flow blood pumps were found to be 17.4 ± 3.6 and 14.0 ± 2.1 s in patients (P=0.526 and P=0.356, respectively). FA also revealed a tendency for increased frequency of dye leakage from the optic disc in our study population. Except for remarkable delays in both ARCT and AVTT as well as a tendency for increased frequency of dye leakage from the optic disc, ophthalmologic evaluations revealed no other significant pathology or vascular deterioration in the retina that could be attributed to artificial heart systems.

Abstract 3909: Assessing the role of tumor vascularity in nanotherapeutics delivery.

Abstract Chemotherapeutic delivery is generally poor in tumors characterized by rapid perfusion and low blood volume fraction. Nanoparticles can be engineered to overcome abnormal flow conditions to act as intravascular drug depots for the localized delivery of high concentrations of chemotherapeutics. We hypothesized that the ability of multi-stage nanotherapeutics to accumulate in tumors is highly dependent on tumor perfusion and that matching particle parameters to tumor-specific flow parameters can improve the delivery of nanotherapeutics. To test this hypothesis, we measured first-pass perfusion of an intra-arterial bolus of FITC-dextran using intravital microscopy (IVM) in 4 patient-derived breast tumor xenograft (PDX) lines: BCM-2665, BCM-4195, BCM-2147, and BCM-3887. These PDX lines were established directly from patient samples and maintain the triple negative biomarker status of the original patient tumors. Selected for their differing vascular morphologies, these 4 tumor lines yielded distinct, reproducible transport features unique to each tissue. BCM-2665 tumors (n=6) were characterized by regions of dense vascularization interspersed with regions of little to no blood flow. BCM-2147 tumors (n=6) were dominated by large tortuous vessels like those observed in BCM-2665 tumors, but also had a well-developed capillary network interconnecting the large vessels. BCM-3887 tumors (n=6) were characterized by an extensive network of poorly defined, dilated, leaky microvessels. BCM-4195 tumors were uniformly covered with a well-defined, widely spaced microvessel network. The arteriovenous transit time (AVTT) was measured by tracking a bolus of 40kDa FITC-dextran through the tumor vasculature in real-time. Both 2665 and 2147 tumors were rapidly perfused (∼10 - 25 seconds), whereas a majority of 3887 and 4195 tumors required ∼45 seconds or more. The blood volume fraction (BVF) varied by nearly an order of magnitude, with 2665 and 2147 tumors exhibiting the lowest BVF (∼0.11 - 0.12). The tracer elimination constant (Kel), which was measured as a surrogate for tumor permeability using time-lapse IVM images, was an order of magnitude lower for 3887 and 4195 tumors (∼0.11/hr vs. ∼1.17/hr) indicating that these tumors are much more permeable than 2665 and 2147 tumors. Interestingly, flow parameters that adversely impact drug accumulation appear to favor particle accumulation. In clinical studies, tumors characterized by rapid perfusion and low blood volume fraction generally respond poorly to chemotherapy and radiation therapy. We have observed this phenomenon in our cancer models: BCM-2665 and BCM-2147 tumors fail to show growth inhibition at clinically relevant doses of docetaxel, whereas BCM-4195 and BCM-3887 tumors show complete growth inhibition. As such, we believe these tumors will provide an excellent model for studying the relative importance of tumor-specific transport features for improving drug delivery. Citation Format: Anne L. Van de Ven-Moloney, Melissa D. Landis, Lacey A. Burey, Mauro Ferrari, Jenny C. Chang. Assessing the role of tumor vascularity in nanotherapeutics delivery. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3909. doi:10.1158/1538-7445.AM2013-3909

Angioarchitecture Determines Obliteration Rate After Radiosurgery in Brain Arteriovenous Malformations

Radiosurgery as a potential treatment modality for brain arteriovenous malformations (AVM) has 60% to 90% obliteration rates. To test whether AVM angioarchitecture determines obliteration rate after radiosurgery. This study was a retrospective analysis of 139 patients with AVM who underwent radiosurgery. Multiple angioarchitectural characteristics were reviewed on conventional angiogram on the day of radiosurgery: enlargement of feeding arteries, flow-related or intranidal aneurysms, perinidal angiogenesis, arteriovenous transit time, nidus type, venous ectasia, focal pouches, venous rerouting, and presence of a pseudophlebitic pattern. The radiation plan was reviewed for nidus volume and eloquence of AVM location. A chart review was performed to determine clinical presentation and previous treatment. Outcome was dichotomized into complete/incomplete obliteration, and various statistics were performed, examining whether outcome status was associated with the investigated factors. Marginal dose ranged from 15 to 25 Gy (mean, 18.8 Gy), with lower doses prescribed in eloquent locations. Sizes of AVMs ranged from 0.08 to 21 cm (mean, 3.78 ± 4.19 cm). Complete AVM obliteration was achieved in 92 patients (66%) and was related to these independent factors: noneloquent location (odds ratio [OR], 3.20), size (OR, 0.88), low flow (OR, 3.47), no or mild arterial enlargement (OR, 3.32), and absence of perinidal angiogenesis (OR, 2.61). Concerning the 3 last angioarchitectural characteristics, if no or only a single factor was present in an individual patient (n = 92 patients), obliteration was observed in 74 (80%); if 2 or 3 factors were present (n = 47), obliteration was observed in 18 patients (38%; OR, 6.62). Angioarchitectural factors that indicate high flow are associated with a lower rate of AVM obliteration after radiosurgery.

A Case of Central Retinal Artery Occlusion after Chiropractic Manipulation of the Neck

Here we report a case of central retinal artery occlusion after chiropractic manipulation on the neck. A 49-year old man presented at the hospital because of sudden visual loss in his right eye after chiropractic neck manipulation. He had received chiropractic manipulation of the neck by a chiropractor eight days prior. When he first visited us, his best corrected visual acuity in his right eye was hand motion. A full ophthalmic examination was performed. There was cherry-red spot in the macula in his right eye. We performed a fluorescein angiogram and cervical color Doppler. The arterio-venous transit time in the fluorescein angiogram was delayed, and we detected stenosis of the right internal carotid artery with diffuse atherosclerotic plaques in the right common carotid artery. We prescribed ginko biloba extract (Tanamin). Three years after his first visit, the best corrected visual acuity of his right eye was 20 / 200.

Fluorescein angiography findings in a case of Rubinstein-Taybi syndrome

The purpose of this report is to describe the fluorescein angiography findings in a case of Rubinstein-Taybi syndrome. Fundus photography and fluorescein angiography were performed on a 6-year-old male with Rubinstein-Taybi syndrome due to CREB binding protein gene mutation. Fundus photography showed glaucomatous cupping and diffusely attenuated retinal vasculature. Choroidal vasculature was prominent due to diffuse retinal atrophy with scattered focal retinal pigment epithelial changes. Fluorescein angiography showed retinal vascular attenuation, prolonged arteriovenous transit time with delayed venous filling, late small vessel leakage, and 360 degrees of peripheral avascularity. Peripheral retinal avascularity and retinal vascular inflammation evidenced by late small vessel leakage can be demonstrated by fluorescein angiography in the retinal dystrophy of Rubinstein-Taybi syndrome.

Spatial Frequency-Based Analysis of Mean Red Blood Cell Speed in Single Microvessels: Investigation of Microvascular Perfusion in Rat Cerebral Cortex

BackgroundOur previous study has shown that prenatal exposure to X-ray irradiation causes cerebral hypo-perfusion during the postnatal development of central nervous system (CNS). However, the source of the hypo-perfusion and its impact on the CNS development remains unclear. The present study developed an automatic analysis method to determine the mean red blood cell (RBC) speed through single microvessels imaged with two-photon microscopy in the cerebral cortex of rats prenatally exposed to X-ray irradiation (1.5 Gy).Methodology/Principal FindingsWe obtained a mean RBC speed (0.9±0.6 mm/sec) that ranged from 0.2 to 4.4 mm/sec from 121 vessels in the radiation-exposed rats, which was about 40% lower than that of normal rats that were not exposed. These results were then compared with the conventional method for monitoring microvascular perfusion using the arteriovenous transit time (AVTT) determined by tracking fluorescent markers. A significant increase in the AVTT was observed in the exposed rats (1.9±0.6 sec) as compared to the age-matched non-exposed rats (1.2±0.3 sec). The results indicate that parenchyma capillary blood velocity in the exposed rats was approximately 37% lower than in non-exposed rats.Conclusions/SignificanceThe algorithm presented is simple and robust relative to monitoring individual RBC speeds, which is superior in terms of noise tolerance and computation time. The demonstrative results show that the method developed in this study for determining the mean RBC speed in the spatial frequency domain was consistent with the conventional transit time method.

Time-resolved mr venography pre catheter-based ablation for atrial fibrillation

Objective The purpose of this study was to evaluate Time-resolved MR venography (TR-MRV) of the pulmonary venous circulation using the time-resolved angiography with interleaved stochastic trajectories (TWIST) method of time-resolved MRA (TR-MRA) and compare it with the more commonly used conventional Contrast enhanced magnetic resonance angiography (CE-MRA) approach in atrial fibrillation patients referred for pre-ablation pulmonary vein mapping. Background Catheter-based ablation of the pulmonary veins prevents recurrence of atrial fibrillation in 70-80% of patients during the first year of follow-up 1,2 . CE-MRA depicts the left atrium and pulmonary veins with high spatial resolution, enabling accurate measurement of pulmonary vein ostia to be made with depiction of their relationship to other structures. 1,3 Conventional CE-MRA however requires timing of contrast enhancement and produces images with overlap of venous and arterial structures, potentially obscuring pulmonary vein ostia. TR-MRA is an alternative to conventional CE-MRA and has been used successfully in other vascular territories. 4 Such an approach may be particularly advantageous in the pulmonary circulation with its rapid arteriovenous transit time, allowing acquisition of pure pulmonary venous phase images with a simpler imaging protocol. Material and methods 26 patients (15 males; age 60.0 ± 12.7y) referred for preablation pulmonary vein mapping underwent both conventional CE-MRA and TR-MRV with TWIST. Imaging was performed on a 1.5 Tesla (MAGNETOM Avanto, Siemens Healthcare) MRI scanner. Source partition and MIP images were evaluated. Quantitative Analysis: Pulmonary vein ostium orthogonal dimensions were measured using double oblique multiplanar reformatting. Qualitative Analysis: For qualitative analysis, both source partition images and MIP images were assessed by two observers. Pulmonary vein conspicuity was scored on a scale of 1-4 (1=poor, 2=fair, 3=good, 4=excellent). The number of pulmonary veins (3 veins= common ostium, 4 veins = normal, 5 veins=accessory vein) was recorded.

Effects of intravitreal anti-vascular endothelial growth factor treatment on retinal vasculature in retinal vein occlusion as determined by ultra wide-field fluorescein angiography.

To investigate both peripheral and central retinal vascular changes after intravitreal anti-vascular endothelial growth factor (VEGF) therapy in the setting of acute retinal vein occlusion (RVO). Two patients with macular edema, one secondary to central RVO (CRVO) and one secondary to branch RVO (BRVO), underwent ultra wide-field (200°) photography and fluorescein angiography before and after a single intravitreal injection of an anti-VEGF agent. The patient with CRVO received an intravitreal injection of ranibizumab (0.5 mg/0.05 mL). The patient with BRVO received an intravitreal injection of bevacizumab (1.25 mg/0.05 mL). The eye with CRVO was reevaluated with ultra wide-field photography and fluorescein angiography at 7 days and 35 days after treatment. The eye with BRVO was reevaluated with ultra wide-field photography and fluorescein angiography at 30 days after treatment. Photographs and fluorescein angiographic results were analyzed for posttreatment changes in arteriovenous transit time, vessel caliber, vessel leakage, peripheral capillary nonperfusion, retinal hemorrhages, and nerve fiber layer infarcts. In both eyes, there were no changes detected in the arteriovenous transit time or peripheral capillary nonperfusion after anti-VEGF therapy. A reduction in intraretinal hemorrhages and nerve fiber layer infarcts was observed at 7 days and 35 days after treatment in the patient with CRVO and at 30 days after treatment in the patient with BRVO. A decrease in vessel caliber was observed at 7 days after treatment in the patient with CRVO and at 30 days after treatment in the patient with BRVO. In the patient with CRVO, an increase in vessel caliber with a recurrence of vascular leakage was noted at the visit on Day 35. Anti-VEGF therapy in the setting of RVO may initially decrease vessel caliber, retinal hemorrhages, and nerve fiber layer infarcts but does not appear to affect arteriovenous transit time or areas of peripheral capillary nonperfusion after a single treatment. The beneficial effects of anti-VEGF therapy in RVO appear transient, and multiple injections may be required for control of macular edema. Ultra wide-field angiography can be a useful tool in monitoring the treatment of RVO.

Quality-Evaluation Scheme for Cerebral Time-Resolved 3D Contrast-Enhanced MR Angiography Techniques

No practical tool has been reported in the literature to evaluate the quality of cerebral TR-3D-CE-MRA techniques. Our study assessed a large list of parameters used to propose a quality-evaluation scheme for TR-3D-CE-MRA. A large list of visual and quantitative parameters used to study the quality of images was collected from the literature and evaluated in 19 healthy patients and 11 patients with arteriovenous shunts who had undergone both CENTRA keyhole TR-3D-CE-MRA at 3T and CCA. Several observers evaluated the visual parameters, such as the diagnostic confidence index, artifacts, maximum vascular signal intensity, arterial-to-venous separation, and visibility of 17 arteries and 7 veins; and quantitative parameters, such as maximum arterial SI, arteriovenous transit time, arteriovenous contrast curve, and ADW. A statistical analysis was used to determine interobserver reproducibility of the visual parameters, to calculate the sensitivity of TR-3D-CE-MRA for detecting each vessel (with CCA as standard of reference), and to compare the results of the visual and quantitative evaluations. Diagnostic confidence index, artifacts, arterial-to-venous separation, and 4 vessels-the PICA, ophthalmic and occipital arteries, and the ISS-demonstrated high reproducibility and sensitivity. The ADW was the most reliable dynamic quantitative parameter and was correlated with arterial-to-venous separation. The image quality of TR-3D-CE-MRA can be effectively evaluated with a scheme of 1 quantitative and 7 visual parameters.

Ocular Ischemic Syndrome Successfully Treated With Carotid Angioplasty and Stenting

Purpose: To report a case of ocular ischemic syndrome successfully treated with delayed carotid angioplasty and stenting (CAS). Case summary: A 52-year-old male was admitted to our hospital because of amaurosis fugax- like symptoms in the right eye for several months. His visual acuity was 0.8 in the right eye and he did not have rubeosis iridis. Neovascularization of the disc, narrowing of the retinal artery and multiple retinal hemorrhages were diagnosed by fundus examination. Fluorescein angiography showed delayed choroidal filling, a delayed arm-to-retina time, prolongation of arteriovenous transit time, neovascularization of the disc, retinal capillary nonperfusion, and staining of the retinal vessels. MR angiography showed severe stenosis in the proximal portion of the right carotid artery. We diagnosed this case as ocular ischemic syndrome. The patient was recommended carotid angioplasty and stenting at the severely narrowed portion of the right carotid artery, but it was postponed about six months after diagnosis because of personal problems. At the final follow-up, 24 months after stenting, the amaurosis fugax symptoms had disappeared, the patient had an improved visual acuity of 1.0, and the new vessels on the disc changed to fibrous tissue. Fluorescein angiography showed resolution of the delayed arm-to-retina time and prolongation of the arteriovenous transit time, disappearances of the leakage around the disc and the retinal capillary nonperfusion.

Peripheral moving‐table contrast‐enhanced magnetic resonance angiography (CE‐MRA) using a prototype 18‐channel peripheral vascular coil and scanning parameters optimized to the patient's individual hemodynamics

To demonstrate that with a priori determination of individual patient hemodynamics, peripheral contrast-enhanced magnetic resonance angiography (pCE-MRA) can be customized to maximize signal-to noise ratio (SNR) and avoid venous enhancement. Using a 1.5T MRI scanner and prototype 18-channel peripheral vascular (PV) coil designed for highly accelerated parallel imaging, geometry (g)-factor maps were determined. SNR-maximized protocols considering the two-dimensional sensitivity encoding (2D SENSE) factor, TE, TR, bandwidth (BW), and flip angle (FA) were precalculated and stored. For each exam, a small aortic timing bolus was performed, followed by dynamic three-dimensional (3D)-MRA of the calf. Using this information, the aorta to pedal artery and calf arteriovenous transit times were measured. This enabled estimation of the maximum upper and middle station acquisition duration to allow lower station acquisition to begin prior to venous arrival. The appropriately succinct SNR-optimized protocol for each station was selected and moving-table pCE-MRA was performed using thigh venous compression and high-relaxivity contrast material. The protocol was successfully applied in 15 patients and all imaging demonstrated good SNR without diagnosis-hindering venous enhancement. By knowing each patient's venous enhancement kinetics, scan parameters can be optimized to utilize maximum possible acquisition time. Some time is added for the timing scans, but in return time-resolved calf CE-MRA, maximized SNR, and decreased risk of venous enhancement are gained.

Thoracic and abdominal MRA with gadofosveset: Influence of injection rate on vessel signal and image quality

The purpose of this study was to investigate the influence of different injection rates on the maximum signal intensity and the arterio-venous transit time of dynamic gadofosveset-enhanced first pass MR angiography (MRA). Twenty-one healthy male volunteers were examined with a time-resolved echo-shared MRA at 1.5 T. The volunteers were assigned into three groups using injection rates of either 1, 2 or 4 ml/s. The maximal signal enhancement and peak signal-to-noise ratio in the pulmonary trunk, the aortic arch, the abdominal aorta as well as both kidneys and lung parenchyma were analyzed. The arterio-venous transit time was determined. The time between maximal enhancement of the pulmonary trunk and the aortic arch was higher with the slow injection rate of 1 ml/s, while there were no differences in the time between maximal enhancement of the aortic arch and the abdominal aorta above or below the origin of the renal veins with all three injection rates. With the slow injection protocol of 1 ml/s a longer purely arterial phase of 10.5 s was achieved compared to 7.7 s with higher injection rates (p = 0.045). The time between maximal aortic signal intensity and maximal renal enhancement was equal for all injection protocols.

Central Retinal Vein Occlusion in Iron Deficiency Anemia

Purpose: To report a case of central retinal vein occlusion caused by iron deficiency anemia in a healthy young adult. Case Summary: A 23-year-old female was referred to the department of ophthalmology after 4 days of acute onset of decreased vision in her left eye. The best corrected visual acuity was 20/20 in the right eye and 10/20 in the left eye. There was no ocular pain, afferent pupillary defect or other ocular symptoms. Results of the anterior segment examination were normal. Fundus examination showed mild optic disc swelling, flame-shaped retinal hemorrhages around the optic disc, and vascular tortuosity with dilatation. The fluorescein angiography showed tortuous peripapillary veins, multiple blocked fluorescences due to retinal hemorrhages, and delayed arteriovenous transit time. All medical examinations and laboratory tests for the risk factors of central retinal vein occlusion were within normal limits, except for iron deficiency anemia. The patient was subsequently treated with oral iron. Three months after the first visit, the best corrected visual acuity was 20/20 in the patient ’s left eye with nearly normal fundus appearances and no iron deficiency anemia detected in laboratory tests. Conclusions: In cases of CRVO in young adults without other systemic diseases and risk factors, evaluation of the hematologic state may be necessary. J Korean Ophthalmol Soc 2009;50(9):1432-1436