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PubMed1986

[Effect of blood movement on the reactivity of blood vessels].

The influence of electrokinetic phenomena arising from blood movement on reactivity of blood vessels has been studied. The potential difference, as it has been established, occurs during blood movement along a vessel between its internal and external surfaces, being dependent upon the rate of blood movement, and the internal one becomes negatively charged. Blood movement facilitates penetration of molecules of dye with a positive charge into a vessel wall. The contractile response of a vessel to the stimulation of vasomotor nerves gradually increases with a start of blood movement and decreases after a blood stop. Artificially applied potential difference between the internal and external vessel surfaces results in the changes of contractile response and vessel tone. The role of electrokinetic phenomena in regulation of contractile ability and vessel tone is discussed.

Animals↗
PubMed1985

Changes of iris vessels in capsular glaucoma: three-dimensional and electron microscopic studies.

Iris specimens were obtained during trabeculectomy from 8 patients with capsular glaucoma. Serial sections for light and electron microscopies were prepared. By light microscopy, a three-dimensional model of the iris vessels accompanied by the pseudoexfoliation (PE) materials stained with toluidine blue was constructed. The PE materials attached to the vessel sometimes at a localized small area and sometimes along a certain length of the vessel; in some parts the vessel was free of the PE materials. By electron microscopy, the PE materials were seen to consist of fluffy fine filaments with the diameter of 20-30 nm and the length of 100-700 nm. They were accumulated underneath the vascular endothelial cells which showed a marked thinning and extended cytoplasmic processes. The accumulation of the PE materials produced a protrusion into the vascular lumen which was narrowed and sometimes completely occluded. The PE materials were mingled with the basement membrane which was displaced and sometimes disrupted. Some vessels surrounded by the PE materials showed marked endothelial degeneration, but some vessels free of the PE materials showed separation of the endothelial junctions leading to extravasation of erythrocytes. The endothelial cells and pericytes of the iris vessels as well as the stromal pigmented cells showed cytoplasmic indentations in which fine filaments with the diameter of 14-20 nm were present and were in close relationship with the cytoplasm at the bottom of the indentations, where the cytoplasmic membrane was indistinct. It was thought that these cells produced the PE materials, although established fine filaments of the PE materials could not be found within the cytoplasm.

Aged↗
PubMed1983

The physiological significance of the endoendothelial fibrin lining (EEFL) as the critical interface in the 'vessel-blood organ' and the importance of in vivo 'fibrinogenin formation' in health and disease.

The author's theory of the endoendothelial fibrin lining (EEFL), first advanced in 1953 and developed by him ever since, localizes the homeostasis between steady fibrin formation and deposition, or 'fibrination', and continuous fibrinolysis in the more or less immobile portion of the plasmatic zone next to the vessel wall. In 1971, the author advanced, in relation to the EEFL, the theory of fibrinogen gel clotting without thrombin action or 'fibrinogenin' formation in vivo. Considerable direct and indirect experimental evidence, secured by the author and by several other investigators, advanced markedly the knowledge of the normal physiology and the pathophysiology of various disease processes involving the vessel wall and blood circulation. The information presented is an extension to that given in the author's recent overview (Clin. Hemorheology 1, 9-72, 1981). It deals both with new data by several investigators including those by the author, as well as with older data from the literature. The author maintained already in 1960 that the blood together with the blood vessels, in which it circulates, constitute 'an entity'. In 1981 he postulated this entity to be a very special organ, named conveniently 'vessel-blood organ', which is ubiquitous and penetrates all other organs and adjacent tissues. The EEFL of the vessel-blood organ is considered by the author as the crucial critical interface between the blood and the vessel wall. It is the primary barrier, followed by the endothelium (comprising the endothelial cells and the interendothelial cement substance which contains or is identical with 'cement fibrin') and the basement membrane for the exchanges between the blood, the vessel wall and its surrounding tissues and spaces. The EEFL acts as anticoagulant, is antithrombogenic, maintains vascular patency and aids cardiac action by decreasing significantly the apparent viscosity of blood, referred to in the literature as the 'Copley-Scott Blair phenomenon'. A new concept of leukocyte emigration traversing the capillary wall is presented, affecting focal fibrinolysis of the EEFL and of fibrin contained in the interendothelial cement substance and in the basement membrane. The physical property of capillary (or vascular) permeability is related to the existence of the EEFL, since, as found by Copley et al, both fibrinopeptides, liberated in the transition of fibrinogen to fibrin, and plasminopeptides, freed in the conversion of plasminogen to plasmin, enhance capillary permeability. Capillary fragility, which is antagonistic to capillary permeability, is in great part due to fibrinolytic action on fibrin as a constituent of the basement membrane.(ABSTRACT TRUNCATED AT 400 WORDS)

Basement Membrane↗
PubMed1984

[Development of the neural apparatus of blood vessels in the common frog in ontogenesis].

The neural apparatus of the aorta, abdominal vein, ischiatic, femoral, pulmonary and caudal vessels has been studied histochemically in tadpoles (the 30th-50th stages of development) and in 1-year-old animals. It has been stated for the first time that in the frog, a representative of the Amphibia class, like in mammals and birds, formation of the adrenergic apparatus in various vessels does not take place simultaneously. For instance, the first adrenergic fibers in the hind limb vessels appear much earlier than in other arteries and veins. The process of the adrenergic innervation development and its completion in vessels of various areas is taking its course differently. In the aorta and in the abdominal vein the formation of the adrenergic plexus develops as increasing density and amount of the mediator in the adrenergic fibers and is completed with maturation in an adult animal. In contrast to these vessels, maturation of the adrenergic apparatus in the hind limb arteries and veins takes place during a shorter interval and is completed at the end of metamorphosis AchE-containing fibers are revealed in tadpoles, as well as in a mature frog only in the aortal arc and in the pulmonary artery. In these vessels the development of cholinergic innervation leaves behind that of the adrenergic innervation, as it does in the vessels of Mammalia, and the human subject.

Adrenergic Fibers↗
PubMed1994

Theoretical foundation on a noninvasive estimation for viscoelastic mechanical property of blood vessels by ultrasonic Doppler effect.

The method used in this paper is developed to estimate the degree of viscoelasticity of the blood vessel wall in a noninvasive mechanical method. In this proposed method, we can obtain an output waveform connected with mechanical behavior of blood vessels by using Ultrasonic Doppler Effect Sensory (UDES). Characterizing parameters on this waveform are established to estimate the mechanical properties of blood vessels. By analyzing the characteristics of these parameters, we attempt to estimate the viscoelastic property of blood vessels. Previously, it was found that these parameters are related to viscoelastic mechanical properties of materials. In this paper, we carried out computer analysis on the mechanical viscoelastic model and compared the theoretical behavior of blood vessels with the experimental output waveform by UDES. From these results, it was proved that values of these parameters connect with the change of the viscoelastic mechanical property of blood vessels. Therefore, the characterizing parameters of experimental output waveforms can be used to estimate the viscoelastic property of blood vessels in a noninvasive method.

Animals↗
PubMed1996

Extracellular matrix molecules influence innervation density in rat cerebral blood vessels.

We have investigated the contribution of the acellular component (i.e., the extracellular matrix, or ECM) in determining the innervation density of peripheral target tissue, and the possible involvement of ECM molecules in age-related axonal atrophy. We addressed this issue using cerebral blood vessels where both the overall density and the density of sympathetic innervation decrease by 50% in aged rats. In order to study the capacity of the ECM to influence pattern and density of innervation, cerebral blood vessels from young (6 weeks) and old (24 months) rats were repeatedly freeze-thawed to kill the cellular component of the vessel wall before transplantation in oculo into young host rats. After 4 weeks, the nature and degree of reinnervation of transplants by host nerves was studied by quantitative immunohistochemistry using PGP9.5 (a general neuronal marker) or CGRP (calcitonin gene-related peptide, a sensory marker), or catecholamine histochemistry using the glyoxylic acid technique to visualise noradrenergic sympathetic nerves. The density of reinnervation was measured by computerized image analysis. The PGP-immunoreactive reinnervation on old transplanted cerebral blood vessels was significantly less dense compared to young ones. However, nerve density on both young and old transplants was lower than on control, ex vivo blood vessels. CGRP-positive nerves on both young and old transplants were sparse, but similar to control tissues, whereas catecholamine-containing nerves were very sparse on all transplants, and significantly less than on control blood vessels. These results suggest that alterations occur in the aged ECM, that make it less receptive to innervation. However, they also indicate that, along with the ECM, factors produced by the cellular components of the blood vessel wall are essential, at least for the maintenance of the sympathetic innervation.

Aging↗
PubMed1996

Development of astrocytes and their relation to blood vessels in fetal monkey retina.

PURPOSE: To determine the development of astrocytes and their vascular relations in Macaca monkey retina. METHODS: Sections and wholemounts of retinas from fetal day (Fd) 65 to adult animals were analyzed immunohistochemically to detect glial fibrillary acidic protein (GFAP) and vimentin. RESULTS: Astrocytes appeared first near the optic disc, then subsequently further peripherally, but avoided the fovea. In the nerve fiber layer, round and ovoid cells extended processes parallel to ganglion cell axons. In the ganglion cell layer, ovoid and stellate cells exhibited anisotropic processes or a honeycomb network. The inner lamina of astrocytes developed ahead of the outer lamina, and both reached their final positions before birth. Astrocytes lay more peripherally than did developing blood vessels, and the growing edge of nerve fiber layer vessels lay between the two astrocytic layers. Spindle cells, which may be vascular precursor cells, often aligned along linear astrocytic processes. Occasional spindle-shaped cells containing GFAP or vimentin were identified as immature glia. Astrocytes and blood vessels coincided regionally during development, but astrocyte processes were typically not in register with the meshwork of growing blood vessels. Astrocyte-vessel associations increased during fetal life and postnatally. CONCLUSIONS: During development, astrocytes display the same bilaminar pattern and morphologies present in adult retina. Astrocytes and blood vessels exhibit a similar regional distribution, but develop in distinct spatial patterns. Vessel investment by astrocytic processes increases during fetal life but is variable at all ages.

Animals↗
PubMed1998

Ganglion cell loss in RCS rat retina: a result of compression of axons by contracting intraretinal vessels linked to the pigment epithelium.

In the dystrophic Royal College of Surgeons (RCS) rat retina, there is a progressive loss of photoreceptors. As a result, the retinal circulation becomes apposed to the retinal pigment epithelium (RPE) and neovascular formations develop. RPE and inner nuclear layer cells migrate along these vessels towards the retinal ganglion cell (RGC) layer. The retinal layers gradually become disrupted, and some of the RGC axon bundles involute into the retina. These bundles are always associated with blood vessels, and there is evidence of axon damage where they juxtapose. In wholemount preparations of dystrophic retinae (> or =6 months of age), abrupt changes are observed in the trajectory of RGC axon bundles, where they are crossed by circumferential vessels. Degenerative profiles can be seen at these locations. Visualisation of RGCs with Fluoro-gold shows wedge-shaped sectors in the dystrophic retina devoid of labelling, initially in the ventral retina but later spreading dorsally. It is hypothesised that the vessels supplying the neovascular formations contract and pull surface vessels into the retina, thus displacing any axon bundles that lie beneath them into the inner plexiform layer. The contractility may be an intrinsic property of the vessels or it may be conferred by the cells migrating along them. Axonal transport becomes blocked at the points of tension, thereby causing retrograde degeneration of the parent RGCs. Because RGC loss is also a feature of human retinitis pigmentosa, the RCS rat may provide a model to test interventions devised to prevent such loss following photoreceptor degeneration. This model also may be useful for testing methods designed to control blood vessel and matrix formation.

Animals↗
PubMed1997

[Usefulness of magnetic resonance angiography in the diagnosis of polar vessel in stenosis of the pyeloureteral junction].

OBJECTIVES: To present the results of a prospective study that had been conducted to determine the accuracy of magnetic resonance angiography (MRA) in the detection of accessory or polar vessels associated with ureteropelvic junction (UPJ) stricture, in order to utilize the most appropriate surgical procedure in the management of this condition. METHODS: From October, 1994 to September, 1996, 30 MRA procedures were done in 12 males and 18 females, aged 14 to 73 years (mean 38.12), with symptomatic UPJ obstruction. When the MRA was positive for polar vessels, the patients underwent open dismembered pyeloplasty; surgical correlation and a true positive result could be established. Percutaneous endopyelotomy was offered when the MRA was negative. The findings at open surgery and an unremarkable clinical course and radiological findings at one year follow-up established a true negative result. RESULTS: Accessory or polar vessels (11 arteries; 4 veins) were found in 11 patients (36.4%). MRA had a sensitivity of 92.3% (15/16) for detection of accessory vessels. Fourteen patients underwent open surgery (11 dismembered pyeloplasties; 3 nephrectomies) and the MRA findings were confirmed in each case (8 positive; 6 negative). Surgery disclosed an accessory vein that had not been detected on MRA in only one patient. This patient also had a polar artery that had been observed on MRA and demonstrated at surgery; thus, the sensitivity of MRA for detection of UPJ stenosis with polar vessel is 100% (11/11). Each vessel described on MRA was confirmed at surgery; there were therefore no false positives and the specificity was 100%. CONCLUSIONS: Although this is a preliminary study with a short follow-up and with some limitations, the results indicate that MRA is a simple, non-invasive technique with a high sensitivity and specificity for detection of polar vessels associated with UPJ stenosis, and appears to be a useful preoperative diagnostic procedure due to the surgical implications.

Adolescent↗
PubMed1997

True reconstruction of vessel geometry from combined X-ray angiographic and intracoronary ultrasound data.

At present a rapidly expanding variety of methods appear to provide three-dimensional (3-D) reconstructions of blood vessels in a patient. Generally the results of such methods look very realistic. However, only a few produce a true 3-D reconstruction. We strongly suggest that for a true 3-D reconstruction of a blood vessel the following criteria should at least be fulfilled: (1) the arterial wall rather than the lumen must be reconstructed; (2) the spatially curved course of the vessel must be included; and (3) the orientation of local vessel wall characteristics, for example, plaque eccentricity, with respect to the luminal course must be correctly maintained. Currently, only methods combining biplane X-ray angiography and intravascular ultrasound imaging (IVUS) have succeeded in providing true 3-D reconstruction of a segment of a vessel. Accuracy of those reconstructions is derived from studies using phantoms having precisely known geometry. In patients, data on accuracy are more difficult to obtain. Nevertheless, a comparison can be made between the actual length of an IVUS pull-back trajectory and its reconstructed length showing relative differences of less than 3%. Further knowledge can be obtained by comparing simulated angiograms derived from the 3-D reconstruction with the real contrast angiograms. True 3-D reconstruction methods of the vessel wall and lumen, applicable in the individual patient, have become feasible and produce accurate results. Application of such a method will be helpful to understand immediate and long-term vessel remodelling induced by all types of catheter interventions and in the study of progression or regression of atherosclerotic wall disease.

Coronary Angiography↗
PubMed1998

[VCS microclip anastomosis on blood vessels of less than 2 millimeters in diameter. Preliminary experimental study in the rat].

The aim of this work was to study the possibilities and limits of the vascular microanastomoses with VCS microclips. VCS Microclips are a new mechanical anastomotic device, allowing a single operator to perform anastomoses without microsutures. The two arcuate limbs of the titanium microclips do not penetrate the vascular intima. The microclip anastomosis technique is based on symmetric eversion of the vessel walls, facilitated by everting forceps. We studied the medium and small Autosuture VCS microclips on different vessels ranging from 0.3 to 2 millimeters in diameter: aorta, carotid artery, femoral artery and femoral vein. Thirty nine end-to-end or end-to-side anastomoses were performed on Wistar rats. These anastomoses were performed by a single operator without the use of sutures. Patency was studied by the "empty and refill" test immediately and at two months. Histologic analysis of the anastomosis was performed at two months (hematein-eosin and orcein stains on longitudinal sections). Four out of thirty nine anastomoses were occluded during the 15 minutes following clamp release. Failure was always due to a technical error and occurred during the first trials. The thirty five other anastomoses were patent immediately and at two months post-operatively, except for the by-pass which was not viable. These anastomoses were still patent 30 minutes post-operatively. Light microscopy analysis confirmed that the microclip extremities did not penetrate the lumen, although the internal media was usually very thin at the level of the microclip jaws, especially for the smallest vessels. For vessels larger than 1 mm in diameter, the microclip extremities were usually outside the internal elastic lamina. No anastomotic aneurysm was found. Vascular healing was comparable with microsutures at 2 months. Microvascular anastomoses performed with microclips have numerous advantages, compared to usual microsutures: they are two to three times quicker, they can be performed step by step without turning the clamp and they can be performed with the right or left hand. There is theoretically no thrombogenic risk. The drawbacks are the need for complementary training and the cost of microclips which is five to six times that of sutures. End-to-side anastomoses of small vessels are more difficult than end-to-end anastomoses. The recipient vessels must be larger than 1.5 mm in diameter, otherwise the anastomosis may become stenosed. Microclips are especially useful to save time, i.e. for multiple anastomoses and for anastomoses of vessels larger than 1 millimeter in diameter. Some modifications of the material could allow vascular or hollow organ anastomoses with endoscopic assistance.

Anastomosis, Surgical↗
PubMed1996

[The individualization of activities of blood vessels].

The functional activities of blood vessels in various organs have their own characteristics, named individuality of blood vessel. One of the most outstanding characteristics is that the responses of blood vessels in various organs to the same stimulation are different, even contradictory. This physiological characteristic of the blood vessel guarantees that the blood vessel can make adjustable responses in varying parts and under different conditions to fulfil the functional tasks of circulatory system and to meet the demands of blood supply of recipient organs. The study of vascular individualization would benefit to explain the mechanism of blood vessel activities and is also important in the study of pathogenesis of vascular diseases. This paper gives a brief description on the vascular mechanisms contributing to the individualization of blood vessel.

Animals↗
PubMed1998

Analysis of blood vessel maturation processes during cyclic ovarian angiogenesis.

Cyclic angiogenic processes in the ovarian corpus luteum (CL) of monovulatory species are characterized by distinct phases of blood vessel growth, vessel maturation, and vessel regression. To characterize molecular and cellular systems that may play a role in regulating blood vessel maturation, we have (a) analyzed the spatiotemporal expression of vascular endothelial growth factor (VEGF) and its receptors VEGF-R1 (Flt-1) and VEGF-R2 (Flk-1) throughout the ovarian cycle, (b) examined the recruitment of pericytes during vessel maturation, and (c) quantitatively measured the ratio of angiopoietin-2 (Ang-2) to angiopoietin-1 (Ang-1) throughout the ovarian cycle. The data indicate that the VEGF/VEGF-receptor system is expressed not only during ovarian angiogenesis, but also with similar intensity in the nonangiogenic midstage CL. In fact, VEGF is expressed through most of the ovarian cycle, only being down-regulated during luteolysis, which leads to regression of the CL neovasculature. Pericytes are recruited soon after the induction of CL angiogenesis following the front of invading endothelial cells. Based on a double-staining immunohistochemistry technique, we developed a microvessel maturation index (MMI) that reflects the percentage of the capillary neovasculature that is associated with pericytes. The MMI in the angiogenic corpus rubrum is approximately 0.60. This value is not significantly higher in the nonangiogenic midstage CL but increases to close to 0.90 during CL regression. Lastly, an RT-PCR analysis of Ang-1 and Ang-2 expression revealed that both molecules are expressed throughout the ovarian cycle. The quantitative Ang-2/Ang-1 ratio does, however, change from 1.34 in the angiogenic CL and 1.07 in the midstage CL to 7.59 during CL regression, reflecting the strong overexpression of Ang-2 over Ang-1 during blood vessel regression. Taken together, the data support a model of a transiently maturated vasculature in the midstage CL, which is characterized by VEGF and pericyte contact-mediated endothelial cell survival and an induction of blood vessel regression during luteolysis that is characterized by the down-regulation of VEGF and the up-regulation of Ang-2.

Angiopoietin-1↗
PubMed1998

Intimal proliferation after stenting reflected by increased stent-to-vessel cross-sectional area ratio: serial intravascular ultrasound study.

Minimizing the extent of neointimal proliferation helps to maintain the maximal vessel lumen after the treatment of stenosis. The present study examined factors influencing the predisposition to neointimal proliferation, which is a consequence of Palmaz-Schatz stenting. Serial intravascular ultrasound examinations of 32 lesions (4 lesions/patient) were performed after stenting and at 6 months follow-up in 8 non-restenotic patients. Vessel, lumen and stent cross-sectional areas (CSA) were measured. Stent-to-vessel CSA ratio at stenting, changes of lumen CSA, vessel CSA and intima CSA (neointimal proliferation) were calculated. Six months after stenting, lumen CSA was reduced corresponding to an increase of intima without change of vessel CSA (without remodeling). Greater stent-to-vessel CSA at stenting was associated with higher neointimal proliferation at follow-up. The proliferative response was the same at all stent edges. Stent CSA was reduced as stent dilation was increased. The stent CSA became smaller but stent shrinkage did not account for late lumen loss. Late lumen loss in stents is the result of neointimal proliferation in cases without restenosis, and a larger stent-to-vessel CSA ratio reflects increased neointimal proliferation, as shown at 6-month follow-up.

Aged↗
PubMed1999

Relation between lymphatic vessel diameter and clinicopathologic parameters in squamous cell carcinomas of the oral region.

BACKGROUND: In an attempt to determine the mechanism of cervical lymph node metastases, the authors studied the relation between lymphatic vessels in or around tumor tissue and lymph node metastases in patients with primary squamous cell carcinoma (SCC) of the oral region by enzyme histochemistry using 5'nucleotidase-alkaline phosphatase. METHODS: The subjects were 23 patients who had biopsy proven oral SCC. After enzyme histochemical staining, the cross-sectional dimension (referred to as diameter) of the lymphatic vessels were measured and analyzed in relation to the T classification of the tumor, degree of tumor differentiation, and mode of invasion. RESULTS: The average diameter of the lymphatic vessels in or around tumor tissue was significantly greater than that in tumor free tissue (P < 0.01). The mode of invasion correlated significantly with the lymphatic vessel diameter (P < 0.01). The diameter did not correlate significantly with the T classification (P range, 0.135-0.254) or tumor differentiation (P = 0.274). The following relation was found between the incidence of cervical lymph node metastases and the mode of invasion: 40.0% of Grade 2 tumors were positive for metastases, 71.4% of Grade 3 tumors were positive, and 75.0% of Grade 4 tumors were positive (grading was according to Jakobsson's classification). CONCLUSIONS: Of the factors evaluated in this study, only the mode of invasion correlated significantly with the diameter of the lymphatic vessels. Although other studies have shown that tumor thickness and perhaps even perineural and blood vessel invasion may be equally important, the findings of the current study suggest that both lymphatic vessel diameter and the mode of invasion may be important factors in the prediction of cervical lymph node metastases.

5'-Nucleotidase↗
PubMed1998

p53, vessel count, and vascular endothelial growth factor expression in human colon cancer.

We previously demonstrated an association between vascular endothelial growth factor (VEGF), vessel counts and metastasis in human colon cancer specimens. Mutant p53 has been implicated in the regulation of angiogenesis. Immuno-histochemical detection of p53 protein has been associated with p53 gene mutations. We sought to determine a correlation between p53 protein detection (i.e., mutant p53), VEGF expression and vessel counts in human colon cancer. Surgical specimens from 93 patients with colon cancer were stained immuno-histochemically for p53, VEGF and factor VIII. Vessel counts were greater in metastatic tumors than in nonmetastatic tumors and adenomas, and greater in nonmetastatic tumors than in adenomas. Vessel counts were highest in tumors with the highest VEGF expression. Vessel counts and VEGF expression were greater in p53-positive tumors than in p53-negative tumors. p53 expression correlated with both VEGF expression and vessel count. The association of p53 expression with VEGF and vessel count suggests that the poor prognosis associated with p53 mutations may be due, in part, to the role of mutant p53 in promoting angiogenesis.

Adenoma↗
PubMed1996

Comparison of clinical and laboratory findings between patients with diffuse three-vessel coronary artery spasm and other types of coronary artery spasm.

Our purpose was to compare patients with diffuse three-vessel coronary artery spasm and other types of coronary artery spasm without significant organic stenosis, and to elucidate clinical characteristics and risk factors. Patients were divided into two groups: group I consisted of 26 patients showing other types of coronary artery spasm; group II consisted of 5 patients with diffuse three-vessel coronary artery spasm. The mean age of patients in groups I and II was 52 and 50 years, respectively. The incidence of variant angina was higher in men than in women. The incidence of smoking was high in each group, but not significantly different. Exercise tests showed no significant differences between groups. All mean values of laboratory data, including lipoprotein (a) and low-density lipoprotein cholesterol in the two groups, were within normal ranges. There was no significant difference between groups. The incidence of spontaneous spam was much higher in patients with diffuse three-vessel coronary artery spasm (P < 0.01). Electrocardiographic (ECG) findings before the spasm were almost normal. All 5 patients with diffuse three-vessel coronary artery spasm demonstrated no important ST segment changes with episodes of angina during a coronary angiography on 12-lead ECG, compared to patients with other types of coronary artery spasm (P < 0.01). First, we conclude, diffuse three-vessel coronary artery spasm mostly occurs spontaneously. Second, we emphasize that diffuse three-vessel coronary artery spasm must be considered when 12-lead ECG shows no important ST segment changes with episodes of angina. Third, it is not easy to distinguish diffuse three-vessel coronary artery spasm from other types of coronary artery spasm on the basis of history, laboratory data, or electrocardiographic findings, including exercise tests.

Angina Pectoris, Variant↗
PubMed1999

MR phase-contrast flow measurement with limited spatial resolution in small vessels: value of model-based image analysis.

Magnetic resonance phase-contrast volume flow rate (VFR) measurement with limited resolution in small vessels is subject to two major sources of error: a) partial volume artifacts, causing systematic overestimation of the VFR, and b) errors related to the selection of vessel pixels [region of interest (ROI)], causing large inter-observer and intra-observer variability. Additionally, limited resolution results in Gibbs-ringing around vessels, which adversely affects VFR determination. In this paper, a semi-automatic model-based method is presented that effectively eliminates errors due to both partial volume effect and Gibbs-ringing and also minimizes errors from variability in the ROI selection. The model assumes a parabolic flow profile and cylindrical vessel geometry, incorporates inflow effects, and takes into account the point-spread function of the acquisition. The method automatically estimates maximum velocity, vessel radius, and VFR. The method is validated in phantoms under various conditions and evaluated in vivo. For small vessels with moderately pulsatile flow, it is demonstrated that accurate VFRs and diameter estimates are obtained, virtually independent of the ROI selection, even in vessels covered by just a few pixels. Compared with conventional VFR analysis, both accuracy and reproducibility improve significantly.

Basilar Artery↗