Mean Vessel Length Research Articles

Vascular feature identification in actinic keratosis grades I-III using dynamic optical coherence tomography with automated, quantitative analysis

Clinical grading of actinic keratosis (AK) is based on skin surface features, while subclinical alterations are not taken into consideration. Dynamic optical coherence tomography (D-OCT) enables quantification of the skin´s vasculature, potentially helpful to improve the link between clinical and subclinical features. We aimed to compare microvascular characteristics across AK grades using D-OCT with automated vascular analysis. This explorative study examined AK and photodamaged skin (PD) on the face or scalp. AKs were clinically graded according to the Olsen Classification scheme before D-OCT assessment. Using an open-source software tool, the OCT angiographic analyzer (OCTAVA), we quantified vascular network features, including total and mean vessel length, mean vessel diameter, vessel area density (VAD), branchpoint density (BD), and mean tortuosity from enface maximum intensity projection images. Additionally, we performed subregional analyses on selected scans to overcome challenges associated with imaging through hyperkeratosis (each lesion group; n = 18). Our study included 45 patients with a total of 205 AKs; 93 grade I lesions, 65 grade II, 47 grade III and 89 areas with PD skin. We found that all AK grades were more extensively vascularized relative to PD, as shown by greater total vessel length and VAD (p ≤ 0.009). Moreover, AKs displayed a disorganized vascular network, with higher BD in AK I-II (p < 0.001), and mean tortuosity in AK II-III (p ≤ 0.001) than in PD. Vascularization also increased with AK grade, showing significantly greater total vessel length in AK III than AK I (p = 0.029). Microvascular quantification of AK unveiled subclinical, quantitative differences among AK grades I-III and PD skin. D-OCT-based microvascular assessment may serve as a supplement to clinical AK grading, potentially raising perspectives to improve management strategies.

Further Test of Pneumatic Method in Constructing Vulnerability Curves Using Six Tree Species with Contrasting Xylem Anatomy

The pneumatic method is a novel method determining vulnerability to embolism in plants, yet it remains unclear whether this method is suitable for all species with different xylem anatomy. In this study, using six tree species with contrasting xylem anatomy, including four vessel-bearing species (diffuse-porous wood and ring-porous wood) and two tracheid-bearing species (non-porous wood), we test the reliability of the pneumatic method by comparing to hydraulic methods and also considering turgor loss point and native embolism. Vessel length distribution and cut-open vessel volume were also evaluated using the silicone injection technique. Additionally, we also synthesized published data to find out the consistency between the pneumatic method and hydraulic methods. Results showed that there was a maximum 10-folds difference in mean vessel length and mean vessel diameter varying from 30 to 56 μm among species. The estimated open vessel volume ranges from 0.064 to 0.397 mL, with a maximum of 14% of the tube vacuum reservoir. For four vessel-bearing species, the pneumatic method showed good consistency with hydraulic methods, and this consistency was evidenced by turgor loss point and native embolism. For two tracheid-bearing species, the pneumatic method significantly overestimated vulnerability because of the bad consistencies with hydraulic methods and plant water relations. Data synthesis of 56 species also suggested that the pneumatic method can accurately measure the embolism vulnerability of vessel-bearing species but not for tracheid-bearing species. Our study provided further evidence that the pneumatic method is accurate for most vessel-bearing species and thus has the potential to be widely used in the plant hydraulics field. However, we proposed that the precise calculation of air discharge volume should take into account the volume of open vessels for species with wide and long vessels.

Changes in and the association of retinal blood perfusion and retinal nerves in diabetic patients without retinopathy.

To explore intraretinal blood flow perfusion and nerve changes, as well as the correlation between them, in diabetic patients without diabetic retinopathy (NDR). Eighty-six NDR patients (86 eyes) who attended the ophthalmology clinic between December 2019 and December 2021 were included. Sixty-four eyes of 64 healthy examined controls in the same period were selected as the control group. The patients underwent routine ophthalmological examination, optical coherence tomography (OCT) and OCT angiography. The average thickness, minimum thickness and thickness of each quadrant except for the superior temporal quadrant of the ganglion cell-inner plexiform layer (GCIPL) in the macular area of the affected eyes in the NDR group were lower than that of the tested eyes in the control group (P < 0.05). The average retinal nerve fibre layer (RNFL) thickness of the NDR group and the superior, inferior and nasal quadrants around the optic disc of the affected eyes in the NDR group were lower compared with the tested eyes in the control group (P < 0.001, P = 0.003, P = 0.001, P = 0.009). The mean vessel length density in the parafoveal and perifoveal areas in the NDR group was positively associated with the mean GCIPL thickness in the macular area (ρ = 0.265, ρ = 0.257 and P < 0.001). No blood flow perfusion parameters in the NDR group were correlated with the RNFL thickness of the corresponding quadrant around the optic disc (P > 0.05). In diabetic patients without diabetic retinopathy, the superficial retinal vessel density in the macular area positively correlated with GCIPL thickness, and the superficial retinal vessel density around the optic disc was not correlated with RNFL thickness.

Computed Analysis of Retinal Vascular Growth After Bevacizumab Treatment of Retinopathy of Prematurity Until Age 3 Years

PurposePremature infants, after anti–vascular endothelial growth factor injections for retinopathy of prematurity, have persistent peripheral avascular retina (PAR). PAR is ablated with laser; however, physiologic growth of the retinal vasculature in the long term has not been measured. The purposes of this study were to measure retinal vessel growth after treatment with intravitreal bevacizumab (IVB) for retinopathy of prematurity, using serial fluorescein angiography (FA), until age 3 years, and to assess the timing for providing laser ablation in PAR. MethodsData from an observational, longitudinal clinical study were collected. Angiographic images of eyes treated with IVB were included; imaging data from laser photocoagulation were excluded. All eyes underwent initial examination under general anesthesia with FA and photographic imaging. The retinal vessel length was measured from the temporal margin of the optic disc passing through the foveal center, and the lengths at subsequent FA were compared. To compare the changes in retinal vessel length over time in individual eyes, a paired-sample t test was performed. FindingsFA images from 70 eyes (35 infants) treated with IVB were available. A total of 150 FA images were available for review; data from 125 images of good quality were used for analysis. The mean postmenstrual ages (PMAs) at first, second, third, and fourth FA were 66.2, 100.9, 135.1, and 180.7 weeks, respectively. The mean retinal vessel length was 14.177 mm at first FA and 13.199 mm at fourth FA (PMA range, 42...234 weeks). Retinal vascular lengths of individual eyes compared over time showed no statistically significant growth from the first FA to age 3 years. The changes in retinal vessel length from first to second FA were –0.117 ± 0.79 mm (p = 0.42; n = 30); from first to third FA, +0.060 ± 0.85 mm (p = 0.79; n = 15); and first to fourth FA, –0.404 ± 1.32 mm (p = 0.45; n = 7). ImplicationsBeyond 65 weeks' PMA, no meaningful retinal vascular growth occurred after IVB up to age 3 years, guiding the timing for physicians if laser photocoagulation is being considered. Future studies are needed to address retinal growth changes in the growing eyes of infants.

The theory behind vessel length determination using gas flow rates and comparison between two pneumatic methods based on seven woody species.

In plants, xylem vessel length is important for long-distance water transport; however, the currently used methods for vessel length measurement are inconvenient and time-consuming. The recently developed semi-automated Pneumatron is a device based on the pneumatic theory that is similar to the air-injection method, and can rapidly estimate vessel length. Mean vessel length was compared between the Pneumatron and the air-injection method in seven woody species with a wide range of vessel lengths (2.3-78.7 cm). The results were consistent between the two methods, regardless of whether the same or different samples were used. The theory underlying the gas flow in vessels was improved and expanded, and compared to that underlying the water flow in order to better understand the pneumatic processes within a stem sample. Moreover, a new and simple equation for gas flow in vessels was derived based on the molar gas flow (mol s-1) rather than volume flow, because the former remains constant with distance throughout the stem axis. We strongly recommend using the Pneumatron in future studies owing to its low cost, convenience, rapidity, and simple operation. However, a number of potential issues need to be considered to avoid artifacts during measurements.

Colocalization of optical coherence tomography angiography with histology in the mouse retina

Optical coherence tomography angiography (OCT-A) allows in vivo, non-invasive, functional imaging of retinal perfusion. The purpose of this study was to determine the reliability of OCT-A in visualizing the complete retinal vasculature by comparing in vivo OCT-A images to matched ex vivo retinal tissue in mice. Adult female C57BL/6 mice were imaged to obtain OCT-A images of the superficial vascular complex, intermediate capillary plexus and deep capillary plexus. Z-stack fluorescence images of whole-mounted retinas, labeled for vascular endothelial cells by anti-isolectin immunohistochemistry and FITC-dextran perfusion, were generated. The OCT-A and fluorescence images were manually colocalized and vessel length measured for each of the techniques. Mean vessel length among all plexuses showed less than 13% difference between OCT-A and lectin immunohistochemistry and less than 4% difference between OCT-A and FITC-dextran perfusion. The strength of the correlation between OCT-A and lectin immunohistochemistry ranged from 0.46–0.95, while that between OCT-A and FITC-perfusion ranged from 0.67–0.88. OCT-A visualized retinal vasculature in vivo to a similar extent in matched ex vivo histology images. Our results show that OCT-A is a reliable method for acquiring in vivo images of retinal perfusion in mice, with the ability to differentiate each vascular plexus.

Tumor Vascular Networks Depicted in Contrast-Enhanced Ultrasound Images as a Predictor for Transarterial Chemoembolization Treatment Response

Hepatocellular carcinoma (HCC) is prevalent worldwide. Among the various therapeutic options, transarterial chemoembolization (TACE) can be applied to the tumor vascular network by restricting the nutrients and oxygen supply to the tumor. Unique morphologic properties of this network may provide information predictive of future therapeutic responses, which would be significant for decision making during treatment planning. The extraction of morphologic features from the tumor vascular network depicted in abdominal contrast-enhanced ultrasound (CEUS) images faces several challenges, such as organ motion, limited resolution caused by clutter signal and segmentation of the vascular structures at multiple scales. In this study, we present an image processing and analysis approach for the prediction of HCC response to TACE treatment using clinical CEUS images and known pathologic responses. This method focuses on addressing the challenges of CEUS by incorporating a two-stage motion correction strategy, clutter signal removal, vessel enhancement at multiple scales and machine learning for predictive modeling. The morphologic features, namely, number of vessels (NV), number of bifurcations (NB), vessel to tissue ratio (VR), mean vessel length, tortuosity and diameter, from tumor architecture were quantified from CEUS images of 36 HCC patients before TACE treatment. Our analysis revealed that NV, NB and VR are the dominant features for the prediction of long-term TACE response. The model had an accuracy of 86% with a sensitivity and specificity of 89% and 82%, respectively. Reliable prediction of the TACE therapy response using CEUS-derived image features may help to provide personalized therapy planning, which will ultimately improve patient outcomes.

Quantitative analyses of diameter and running pattern of choroidal vessels in central serous chorioretinopathy by en face images

This study was to investigate the choroidal vessels in eyes with central serous chorioretinopathy (CSC) quantitatively. We studied 41 CSC eyes and their fellow eyes, and 41 normal eyes of 41 age-adjusted individuals. En-face optical coherence tomography image of the top 25% slab of Haller’s layer was analyze. The mean vessel area, vessel length, and vessel diameter were calculated. The running pattern of the vessels was quantified and used to determine the degree of symmetry, the “symmetry index”. The vessel area of CSC eyes was not significantly different from that of fellow eyes but significantly larger than that of normal eyes. The vessel length of CSC eyes was not significantly different from fellow eyes but significantly shorter than that of normal eyes. The mean vessel diameter was larger in CSC eyes than in the fellow eyes and the normal eye. The symmetry index was not significantly different in CSC eyes from that of their fellow eyes but was smaller than that of normal eyes. The quantitative analysis showed that eyes with CSC had larger choroidal vessels and asymmetrical vessels running in Haller’s layer.

Antiangiogenic Activity of Oregano (Origanum Vulgare) Aqueous Extract In-Vivo Through Chick Chorioallantoic Membrane (Cam) Assay

Angiogenesis is the formation of new blood vessels and is required in tumor growth, metastasis and cancer progression. Philippine traditional medicine preparations have shown a comprehensive and function- regulating characteristics. Oregano (Origanum vulgare) is an annual succulent herb which distributed throughout the world. Currently, there have been some related reports on the preventive effects on chronic diseases such as cancer and heart diseases with oregano. The study aimed to evaluate the antiangiogenic activity of oregano crude leaf extract through Chick Chorioallantoic Membrane (CAM) assay. The density and length (per branching) of the blood vessels were measured through a microscope and ToupView software calibrated using a micrometre respectively. The researchers analyzed the data gathered using one-way Analysis of Variance (ANOVA), post hoc tests were also performed using Duncan Multiple Range Test (DMRT) to confirm the results of the ANOVA. Statistical results in the mean blood vessel density and length of blood vessels among the treatments which is at .001 and .000 respectively is lesser than the 0.05 level of significance which rejects the null hypothesis. DMRT results confirm the significant differences among the treatments. The results indicate that the crude leaf extract of Origanum vulgare significantly reduced the length and density of the blood vessels of chick chorioallantoic membrane, indicating its angiogenesis inhibiting capabilities. These results suggest that antiangiogenic effects of crude leaf extract of Origanum vulgare may be mediated via its antioxidant and anticancer effects.

Multiscale quantification of tumor microarchitecture for predicting therapy response using dynamic contrast-enhanced ultrasound imaging.

Hepatocellular carcinoma (HCC) is the most common liver cancer with 1 million cases globally. A current clinical challenge is to determine which patients will respond to transarterial chemoembolization (TACE) as effective delivery of the embolic material may be influenced by the tumor vascular supply. The purpose of this study is to develop a novel image processing algorithm for improved quantification of tumor microvascular morphology features using contrast-enhanced ultrasound (CEUS) images and to predict the TACE response based on these biomarkers before treatment. A temporal sequence of CEUS images was corrected from rigid and non-rigid motion artifacts using affine and free form deformation models. Subsequently, a principal component analysis based singular value filter was applied to remove the clutter signal from each frame. A maximum intensity projection was created from high-resolution images. A multiscale vessel enhancement filter was first utilized to enhance the tubular structures as a preprocessing step before segmentation. Morphological image processing methods are used to extract the morphology features, namely, number of vessels (NV) and branching points (NB), vessel-to-tissue ratio (VR), and the mean vessel length (VL), tortuosity (VT), and diameter (VD) from the tumor vascular network. Finally, a support vector machine (SVM) is trained and validated using leave-one-out cross-validation technique. The proposed image analysis strategy was able to predict the patient outcome with 90% accuracy when the SVM was trained with the three features together (NB, NV, VR). Experimental results indicated that morphological features of tumor microvascular networks may be significant predictors for TACE response. Reliable prediction of the TACE therapy response may help provide effective therapy planning.

Photodynamic Therapy Versus Glucose for the Treatment of Telangiectasia: A Randomised Controlled Study in a Rabbit Ear Model

Telangiectasia is a common venous formation that mainly affects women and causes discomfort, including psychological distress. This study compared photodynamic therapy (PDT) with glucose for vessel sclerosis in a rabbit ear model. Thirty-six ears of 18 rabbits were randomly divided into four groups: Group 1: only injection of Photogem (4mg/mL); Group 2: only light (635nm, 100mW/cm2, 8min, 48J/cm2); Group 3: glucose 75% injection; Group 4: PDT procedure with injection of Photogem and illumination immediately after. Injections were made into the central ear artery. After injection or sham procedures, manual compression of the marginal vein was maintained for 8min in all ears. Follow up was immediately after the procedures, and one and six days later. The percentage of length reduction of spider veins, the target vessels, was analysed in digital photographs with Image J software. Ear thermographs were made with a thermocamera device and average temperatures were collected for analysis. Ear biopsies were obtained after six days. Endothelium average, inflammation, fibrosis, necrosis, skin burn, and vascular thrombosis were assessed using a specific score. The mean vessel length reduction was 26% for Group 4, 2.4% for Group 3, .4% for Group 1, and 0 for Group 2, highlighting that in Group 4, the vessel lengths were significantly reduced compared with the other groups (p<.001). In the thermal analysis, in Group 3, the temperature was unchanged from the initial temperature and the central diameter vessel increased after six days, while, in Group 4, the temperature decreased and the vessels were not clearly detected, suggesting a reduction of the vessels and smaller infusion. Histology showed no difference among groups and one case of necrosis was found in Group 4. PDT was associated with significantly more target vessel sclerosis than glucose injection and controls.

Characterization of lenticulostriate arteries with high resolution black-blood T1-weighted turbo spin echo with variable flip angles at 3 and 7 Tesla

ObjectivesThe lenticulostriate arteries (LSAs) with small diameters of a few hundred microns take origin directly from the high flow middle cerebral artery (MCA), making them especially susceptible to damage (e.g. by hypertension). This study aims to present high resolution (isotropic ∼0.5 mm), black blood MRI for the visualization and characterization of LSAs at both 3 T and 7 T. Materials and methodsT1-weighted 3D turbo spin-echo with variable flip angles (T1w TSE-VFA) sequences were optimized for the visualization of LSAs by performing extended phase graph (EPG) simulations. Twenty healthy volunteers (15 under 35 years old, 5 over 60 years old) were imaged with the T1w TSE-VFA sequences at both 3 T and 7 T. Contrast-to-noise ratio (CNR) was quantified, and LSAs were manually segmented using ITK-SNAP. Automated Reeb graph shape analysis was performed to extract features including vessel length and tortuosity. All quantitative metrics were compared between the two field strengths and two age groups using ANOVA. ResultsLSAs can be clearly delineated using optimized 3D T1w TSE-VFA at 3 T and 7 T, and a greater number of LSA branches can be detected compared to those by time-of-flight MR angiography (TOF MRA) at 7 T. The CNR of LSAs was comparable between 7 T and 3 T. T1w TSE-VFA showed significantly higher CNR than TOF MRA at the stem portion of the LSAs branching off the medial middle cerebral artery. The mean vessel length and tortuosity were greater on TOF MRA compared to TSE-VFA. The number of detected LSAs by both TSE-VFA and TOF MRA was significantly reduced in aged subjects, while the mean vessel length measured on 7 T TSE-VFA showed significant difference between the two age groups. ConclusionThe high-resolution black-blood 3D T1w TSE-VFA sequence offers a new method for the visualization and quantification of LSAs at both 3 T and 7 T, which may be applied for a number of pathological conditions related to the damage of LSAs.

Physical and anatomical properties: the case of two progenies of Melia dubia Cav

Two progenies of Melia dubia plantation of six year old were selected for studies on physical and anatomical properties of wood. Data for each selected trees progenies selected were recorded for height, clear bole length, diameter at breast height, initial moisture content, specific gravity and sapwood proportion. Macroscopic features were observed and recorded under 10 x lenses. Slides were prepared for microscopic views of the wood in three directions viz. pith, middle and periphery. Maceration was done as per Schultze's method to prepare slides for studies on fiber and vessel morphology of the wood samples. The analysis revealed that wood of M. dubia showed distinct growth rings, the sapwood was yellowish white in colour, the heartwood was yellowish brown in colour. The mean moisture content in the living trees was recorded to be 80.3%. The specific gravities of selected progenies were 0.43 and 0.35. The difference in specific gravities between the progenies was statistically significant. Mean sapwood % in both the progenies was 39.12 %. While the mean fiber length was 716.72µm, mean fiber wall thickness was 4.15µm. Mean vessel length of the progenies was 260.5 µm. Significant variability in physical and mechanical properties of wood, indicates a need of careful tree breeding programme for the species.

The chemical identity of intervessel pit membranes in Acer challenges hydrogel control of xylem hydraulic conductivity.

Ion-mediated enhancement of the hydraulic conductivity of xylem tissue (i.e. the ionic effect) has been reported for various angiosperm species. One explanation of the ionic effect is that it is caused by the swelling and shrinking of intervessel pit membranes due to the presence of pectins and/or other cell-wall matrix polymers such as heteroxylans or arabinogalactan-proteins (AGPs) that may contain acidic sugars. Here, we examined the ionic effect for six Acer species and their pit membrane chemistry using immunocytochemistry, including antibodies against glycoproteins. Moreover, anatomical features related to the bordered pit morphology and vessel dimensions were investigated using light and electron microscopy. The ionic effect varied from 18 % (± 9) to 32 % (± 13). Epitopes of homogalacturonan (LM18) and xylan (LM11) were not detected in intervessel pit membranes. Negative results were also obtained for glycoproteins (extensin: LM1, JIM20; AGP glycan: LM2), although AGP (JIM13)-related epitopes were detected in parenchyma cells. The mean vessel length was significantly correlated with the magnitude of the ionic effect, unlike other pit or vessel-related characteristics. Our results suggest that intervessel pit membranes of Acer are unlikely to contain pectic or other acidic polysaccharides. Therefore, alternative explanations should be tested to clarify the ionic effect.

Vessel length and conductivity of Ulmus branches: ontogenetic changes and relation to resistance to Dutch elm disease

Changes in age of the hydraulic architecture of Ulmus minor and U. minor × U. pumila juvenile wood were studied and related to tolerance to Dutch elm disease (DED). The xylem vessel dimensions and the conductivity to air of 2- to 7-year-old branches were analyzed and quantified. No obvious differences in vessel length distribution and conductivity were found to explain differences in DED tolerance among the U. minor clones, or, at the taxon level, the higher DED tolerance of U. minor × U. pumila. Among the U. minor clones, the more susceptible one had wider vessels and a higher maximum vessel diameter than the more tolerant clone. Relations between vessel lengths, vessel diameters and branch sizes were highly significant, and varied between taxa. The diameter and length of vessels increased with age, and average values stabilized 1–2 years earlier for U. minor than for U. minor × pumila. Mean maximum vessel length was significantly higher in U. minor and increased more with age and maximum vessel diameter than in U. minor × pumila. With each 0.2 m increase in height up the stem, conductivities for U. minor and U. minor × U. pumila decreased by 59 and 50 %, respectively, probably due to shortening of the vessels. The implications of xylem structure for the means of pathogen movement and resistance to DED are discussed.

A global analysis of xylem vessel length in woody plants

Vessels are the chief conduit for long-distance water transport in the majority of flowering plants. Vessel length is a key trait that determines plant hydraulic efficiency and safety, yet relatively little is known about this xylem feature. • We used previously published studies to generate a new global data set of vessel length in woody plants. These data were used to examine how evolutionary history, plant habit, environment, and growth ring porosity influenced vessel length. We also examined the relationship between mean vessel length and mean vessel diameter and maximum vessel length. • Data on mean vessel length were available for stems of 130 species and on maximum vessel length for stems of 91 species. A phylogenetic analysis indicated that vessel length did not exhibit significant phylogenetic signal. Liana species had longer vessel lengths than in tree or shrub species. Vessel diameter was not predictive of mean vessel length, but maximum vessel length strongly predicted mean vessel length. Vessel length did not vary between species that differed in growth ring porosity. • Many traits often assumed to be linked to vessel length, including growth ring porosity and vessel diameter, are not associated with vessel length when compared interspecifically. Sampling for vessel length has been nonrandom, e.g., there are virtually no data available for roots, and sampling for environment has been confounded with sampling for habit. Increased knowledge of vessel length is key to understanding the structure and function of the plant hydraulic pathway.

An evaluation of carrier agents for desferoxamine, an up-regulator of vascular endothelial growth factor

Avascularity and hypoxia result in avascular necrosis and play a negative role in fracture healing. The FDA-approved iron chelating agent, desferoxamine (DFO) in a liquid form, has been shown to induce angiogenesis and improve fracture healing through upregulation of the vascular endothelial growth factor. We were concerned that local injection of DFO would either fail to adequately deliver sufficient drug to the desired site or lead to undesired delivery to adjacent sites. Therefore, a sustained release delivery system was desirable to direct DFO to the intended site. Calcium sulfate pellets, collagen sponges, and demineralized cortical bone matrix were all evaluated as potentially controlled release systems for DFO using a fetal mouse metatarsal angiogenesis assay. Angiogenesis was analyzed using a vascularity grading scale, by measuring the mean vessel length of the 5 longest vessels, and by counting the mean number of vessels per metatarsal. Although there was some evidence of angiogenesis with all three carriers, DFO loaded CaSO4 pellets increased vascularity grading, the mean length of the five longest vessels, and the mean number of vessels, all by statistically significant margins versus the control. These results suggest that CaSO4 pellets could be used as a viable, nontoxic, controlled release system for DFO in clinical situations where increased angiogenesis and bone growth are desirable.

Coronary anomalies assessed by whole‐heart isotropic 3D magnetic resonance imaging for cardiac morphology in congenital heart disease

To determine the value of whole-heart three-dimensional magnetic resonance imaging (MRI) for coronary artery imaging in children/adolescents with congenital heart disease (CHD). Forty children/adolescents (median age: 14 years, range 2.6-25.8) with CHD underwent free-breathing navigator-gated isotropic three-dimensional steady-state free-precession (3D-SSFP) MRI for cardiac morphology. Two observers independently evaluated visibility of origin, course, vessel lengths, image quality (IQ), and contrast between coronary lumen and myocardium. A subgroup was compared with cardiac catheter. The total scan time was 6.3 +/- 3.2 minutes (mean +/- SD, at mean heart rate 76 +/- 15/min). The mean vessel length for right coronary artery (RCA) by observer 1 was 97 +/- 43 mm (observer 2: 94 +/- 37 mm), for left main and anterior descending artery (LM/LAD) 91 +/- 40 mm (observer 2: 90 +/- 40 mm), and for left circumflex artery (LCX) 64 +/- 28mm (observer 2: 66 +/- 28 mm). The mean vessel contrast was 0.34 +/- 0.05 (range: 0.23-0.45; maximum = 1, minimum = 0). On a 4-level score (1 = nondiagnostic, 4 = excellent), mean IQ scores ranged between 2.3-2.9 (+/-0.8-1.0). Both observers agreed on the presence/proximal course of RCA in 40/40, LM/LAD in 38/40, and LCX in 36/40 patients. There was complete agreement with invasive coronary angiography available in 12/40 patients (six anomalies). Isotropic whole-heart 3D-MRI for cardiac morphology allows reliable discrimination between normal and abnormal coronary anatomy in children/adolescents with CHD.

Morphometry of retinal vasculature in Antarctic fishes is dependent upon the level of hemoglobin in circulation

We quantitatively assessed ocular vascular patterns of six Antarctic notothenioid fishes that vary in their expression of the circulating oxygen-binding protein, hemoglobin (Hb). Digital image analyses revealed marked differences in vessel morphometries among notothenioid species. Hemoglobinless (-Hb) icefishes display mean vessel length densities that are greater (Chaenocephalus aceratus, 5.51+/-0.32 mm mm(-2); Champsocephalus gunnari, 5.15+/-0.50 mm mm(-2)) than those observed in red-blooded (+Hb) species (Gymnodraco acuticeps, 5.20+/-0.46 mm mm(-2); Parachaenichthyes charcoti, 4.40+/-0.30 mm mm(-2); Trematomus hansoni, 3.94+/-0.08 mm mm(-2); Notothenia coriiceps, 2.48+/-0.21 mm mm(-2)). -Hb fishes also have mean vessel diameters that are approximately 1.5 times greater than vessel diameters of +Hb species (-Hb, 0.193+/-0.006 mm; +Hb, 0.125+/-0.005 mm). Vascular density index (VDI), a stereological index that is affected by both vessel number and length, is greatest in -Hb C. aceratus (3.51+/-0.20) and lowest in +Hb N. coriiceps (1.58+/-0.14). Among four +Hb species, there is a direct relationship between red blood cell content and retinal vasculature. Hematocrit (Hct) is inversely correlated to vascular density (r(2)=0.934) and positively correlated to intervessel distance (r(2)= 0.898) over a >2.3-fold range of Hct. These results indicate that anatomical capacity to supply blood to the retina increases to compensate for decreases in oxygen-carrying capacity of the blood.

Perforating Arteries of the Gluteal Region

Gluteal artery perforator flaps have gained popularity due to reliability, preservation of the muscle, versatility in flap design without restricting other flap options, and low donor-site morbidity. Today, free or local flaps based on the perforating arteries of the gluteal region are among the most commonly used procedures for the management of lumbosacral defects and autologous breast reconstruction. An anatomic study was carried out to investigate localization, dimension, and distribution of the perforator arteries in 16 gluteal regions of 8 formol-fixed cadavers. The total number of perforators in each gluteal region was 13-20 (mean 17 arteries). Mean vessel diameter and mean vessel length were 1.1 mm (range 0.7-1.7 mm) and 6.4 cm (range, 5.2-9.1), respectively. Topographic analysis of the perforators revealed that the gluteal region can be divided into 3 parts in terms of vessel density. The majority of the perforators were localized in superior zone, whereas the middle zone was documented to be the poorest region. Data derived from this analysis were also confirmed by individual analysis of each cadaver.