Longer Segments Research Articles

Adherence to Biopsy Guidelines for Barrett's Esophagus Surveillance in the Community Setting in the United States

Current surveillance guidelines for Barrett's esophagus (BE) recommend extensive biopsies to minimize sampling error. Biopsy practice patterns for BE surveillance in the community have not been well-described. We used a national community-based pathology database to analyze adherence to guidelines and to determine whether adherence was associated with dysplasia detection. We identified 10,958 cases of established BE in the Caris Diagnostics pathology database from January 2002-April 2007. Demographic, pathologic, and endoscopic data were recorded. Dysplasia was categorized as low grade, high grade, or adenocarcinoma. Adherence was defined as > or =4 esophageal biopsies per 2 cm BE or a ratio > or =2.0. Generalized estimating equation multivariable analysis was performed to assess factors associated with adherence, adjusted for clustering by individual gastroenterologist. A total of 2245 BE surveillance cases were identified with linked endoscopy reports that recorded BE length and could be assessed for adherence. Adherence to guidelines was seen in 51.2% of cases. In multivariable analysis, longer segment BE was associated with significantly reduced adherence (3-5 cm, odds ratio [OR] 0.14, 95% confidence interval [CI] 0.10-0.19; 6-8 cm, OR 0.06, 95% CI 0.03-0.09; > or =9 cm, OR 0.03, 95% CI 0.01-0.07). Stratified by BE length, nonadherence was associated with significantly decreased dysplasia detection (summary OR 0.53, 95% CI 0.35-0.82). Adherence to BE biopsy guidelines in the community is low, and nonadherence is associated with significantly decreased dysplasia detection. Future studies should identify factors underlying nonadherence as well as mechanisms to increase adherence to guidelines to improve early detection of dysplasia.

Understanding the effectiveness of online digital music sampling: an exploratory study

Despite the popularity of online digital music and the broad application of digital music sampling, in the existing literature, there is a lack of substantial studies that examine online digital music sampling. This study uses a laboratory experiment to explore the determinants of the five effectiveness dimensions, i.e., evaluation, Willingness-to-Pay (WTP), perceived sampling usefulness, sampling cost and the likelihood of being a free rider, of online digital music sampling. Digital music samples with a higher quality and longer segments were found to increase the sampler's music evaluation and make the evaluation process more useful. Also, the sampler's music evaluation significantly determines his/her WTP. Higher music evaluations not only decrease the sampler's sampling cost during the sampling process, but also reduces the probability that the sampler will take the music sample as a substitute for the original music. This study also shows that the current practice of online digital music sampling is not ideal and music retailers could improve their music sampling strategies by providing digital music samples with longer segments and of higher quality. All of these findings have significant implications for music retailers to use digital music sampling strategies better.

A study of disrupted carotid plaque using high-resolution MRI

Objective To evaluate distribution features of disrupted carotid plaque. Methods Forty-three subjects with duplex ultrasound evidence of 50% to 99% stenosis were retrospectively analyzed. Plaques were categorized as disrupted if there was MRI evidence of fibrous cap rupture. Quantity measured areas of the lumen (LA), wall (WA), and plaque components. The morphological parameters used were total vessel area, vessel burden index, eccentricity index. Mann-Whitney test and Chi-square test appropriate used SPSS (v. 12.0 ). Results There were 17 disrupted and 26 undisrupted lesions identified for comparison. Disrupted plaques showed a predominance of longer longitudinal length of large lip nucleus along the vessel wall (6 mm vs. 0 mm, U = 126, P <0.05 ), a large vessel burden (0.67 vs. 0.59, U =105, P <0.05), and high prevalence of thrombus (82.4% vs. 42.3 %, U = 132,P <0.05). In addition, disrupted plaques showed a different pattern of plaque distribution, having a more eccentric position of the lumen (3.68 vs. 2.79, U = 126, P < 0.05 ), a smaller lumen area (23.97 mm2 vs. 30. 18 mm2, U = 138, P<0.05) and a longer segment of stenosis when compared with the intact plaques. Conclusions Disrupted plaques have significantly different characteristics in terms of both axial and longitudinal distribution. A combination of multi-plane and multi-contrast high resolution MRI may provide valuable information about overall lesion morphology and its association to vulnerability. Key words: Carotid stenosis; Magnetic resonance imaging; Imaging process, computer-assisted

Quality of Barrett??s surveillance in The Netherlands: a standardized review of endoscopy and pathology reports

The quality of Barrett's surveillance relies on an adequate endoscopic inspection, obtaining a sufficient number of biopsy specimens, good communication of the endoscopic findings to the pathologist, and an accurate description of the histological findings by the pathologist. The aim of this study was to assess the quality of Barrett's surveillance in daily practice in The Netherlands. A structured scoring list was developed to evaluate systematically the quality of endoscopy and pathology reports. From 15 hospitals, endoscopy reports and corresponding pathology reports were selected randomly and evaluated by two observers. In case of disagreement, the observers re-evaluated the reports in a consensus meeting. One hundred and fifty cases were evaluated. The adherence to current standard biopsy protocols (four quadrant biopsies every 2 cm) decreased with increasing Barrett's length: 0-5 cm: 79%; 5-10 cm: 50%; 10-15 cm: 30%. The indication for the endoscopy was mentioned in 28% of the pathology reports, in 4% the presence/absence of oesophagitis was communicated, and in 19% the location and/or aetiology of biopsies was described. The presence/absence of dysplasia was mentioned in 93% of pathology reports. Endoscopy reports and pathology reports in current practice do not include all relevant information for an adequate Barrett's surveillance. In short Barrett's oesophagus, the adherence to current standard biopsy protocols is acceptable, but in longer segments (with a higher risk for neoplastic progression) this is clearly insufficient. The communication between endoscopists and pathologist is suboptimal.

Development of Gossypium barbadense chromosome segment substitution lines in the genetic standard line TM-1 of Gossypium hirsutum

Chromosome segment substitution lines (CSSL) consist of a battery of near-isogenic lines that have been developed and cover the entire genome of some crops. With the exception of one homozygous chromosome segment transferred from a donor parent, the remaining genome of each CSSL line is the same as the recipient parent. It is an ideal material for genome research and particularly QTL mapping. In the present study, we first developed one set of CSSL lines using G. hirsutum acc. TM-1 (the genetic standard), as the recipient parent and G. barbadense cv. Hai7124 as the donor parent using molecular assisted-selection in BC5S1–3 generations. The CSSL consisted of 330 different lines, in which 1–4 different lines had the same or overlapping substituted segments. The genetic length of the substituted segments covered 5271.9 cM with an average segment distance of 10.9 cM, 1.5 times the total genetic length of Upland cotton (3514.6 cM). The substituted segments of each line varied in length, ranging from 3.5 cM for the shortest segment to 23.2 cM in the longest segment. Our CSSL have not yet to cover the entire tetraploid cotton genome, due to the absence of some donor parent interval segments.

Mortality in micro-premature infants with necrotizing enterocolitis treated by primary laparotomy is independent of gestational age and birth weight

Previous reports indicate that mortality in micro-premature infants with surgical necrotizing enterocolitis (NEC) is inversely proportional to gestational age and birth weight. We have observed that patterns of survival in micro-premature infants with NEC appear to be changing and may be influenced by the use of primary laparotomy (PL). Thirty-one infants <1,500 g who underwent surgery for NEC were classified into two subgroups: extremely low birth weight infants <1,000 g (ELBW, N = 17) and very low birth weight infants 1,000-1,500 g (VLBW, N = 14) and the groups were compared. Data were retrospectively collected and analyzed using Chi-square or Fisher's exact tests for categorical variables and Wilcoxon rank sum test for continuous variables. All 31 patients (100%) had radiographic evidence of pneumatosis intestinalis and all had operative findings of intestinal necrosis while 20/31 (67%) had intestinal perforation. Surgical mortality was 25% (7/28). Three additional patients died greater than 3 months after surgery of causes unrelated to NEC or surgery yielding an overall mortality of 32% (10/31). There were no significant differences in mortality between ELBW and VLBW patients (P = 0.42). The only variables associated with increased mortality were pannecrosis and longer segment of necrotic bowel (P = 0.005). In our neonatal unit, the mortality of micro-premature infants less than 1,500 g with surgical NEC appears to be independent of gestational age and birth weight. Although the small sample size may mitigate the validity of this study, we found that the most important determinants of mortality were pannecrosis and longer length of necrotic bowel.

Molecular traffic control for a cracking reaction

We investigate the conditions for reactivity enhancement of a catalytic cracking process in porous crystalline solids using the concept of molecular traffic control (MTC). Using dynamic Monte Carlo simulations we obtain a quantitative description of the MTC effect for a bimodal network of intersecting size-selective channels over a wide range of grain parameters, diffusivities and reaction constants, and external operating conditions. The results are compared with those obtained on a similar network but with only one type of channels, called the reference system. We find significant reactivity enhancement in the MTC system with respect to the reference system. This effect is observed to increase with the grain size, and also with longer segments between lattice intersections. We find that in certain regions of the microscopic reaction rate the reactivity enhancement is up to 68%.

Miscibility and Crystallization in Binary Crystalline Blends of Poly(butylene terephthalate) with Poly(butylene terephthalate--caprolactone)

Poly(butylene terephthalate)/poly(butylene terephthalate--caprolactone) is a new A/AxB1x binary crystalline blend with intra-molecular repulsion interaction. Using the mean-field binary interaction model, the value of interaction parameter between the butylene terephthalate and caprolactone structural unit was first reported to be 0.305. This blend exhibited different crystallization behavior from a typical homo-polymer/copolymer blend, which was carefully investigated by differential scanning calorimetry. It was found that poly(butylene terephthalate--caprolactone) copolymers have a great effect on the pure poly(butylene terephthalate) chain mobility and poly(butylene terephthalate) crystalline lattice packing. In the meantime, the crystallization of butylene terephthalate segments in copolymers was restricted by the previously formed poly(butylene terephthalate) crystallites. The two constituents for blending can not form a co-crystal in the range of composition even if they have the same butylene terephthalate unit. It can be concluded that longer segments in a copolymer would be beneficial for the formation of a co-crystal in blends.

A Weakened Transcriptional Enhancer Yields Variegated Gene Expression

Identical genes in the same cellular environment are sometimes expressed differently. In some cases, including the immunoglobulin heavy chain (IgH) locus, this type of differential gene expression has been related to the absence of a transcriptional enhancer. To gain additional information on the role of the IgH enhancer, we examined expression driven by enhancers that were merely weakened, rather than fully deleted, using both mutations and insulators to impair enhancer activity. For this purpose we used a LoxP/Cre system to place a reporter gene at the same genomic site of a stable cell line. Whereas expression of the reporter gene was uniformly high in the presence of the normal, uninsulated enhancer and undetectable in its absence, weakened enhancers yielded variegated expression of the reporter gene; i.e., the average level of expression of the same gene differed in different clones, and expression varied significantly among cells within individual clones. These results indicate that the weakened enhancer allows the reporter gene to exist in at least two states. Subtle aspects of the variegation suggest that the IgH enhancer decreases the average duration (half-life) of the silent state. This analysis has also tested the conventional wisdom that enhancer activity is independent of distance and orientation. Thus, our analysis of mutant (truncated) forms of the IgH enhancer revealed that the 250 bp core enhancer was active in its normal position, ∼1.4 kb 3′ of the promoter, but inactive ∼6 kb 3′, indicating that the activity of the core enhancer was distance-dependent. A longer segment – the core enhancer plus ∼1 kb of 3′ flanking material, including the 3′ matrix attachment region – was active, and the activity of this longer segment was orientation-dependent. Our data suggest that this 3′ flank includes binding sites for at least two activators.

Demographic independence along ecosystem boundaries in Steller sea lions revealed by mtDNA analysis: implications for management of an endangered species

Previous genetic studies indicate Steller sea lions ( Eumetopias jubatus (Schreber, 1776)) comprise three phylogeographically distinct populations. However, differences in population trends and ecology and the limited extent of recorded dispersal suggest structure may be present at smaller scales. We examined sequence variation within a longer segment (531 bp) of the mtDNA control region in greater numbers (n = 1654) of sea lions from across Alaska than earlier investigations to investigate fine-scale dispersal patterns in Steller sea lions. We detected high levels of haplotypic diversity (h = 0.934) and confirmed phylogeographic differentiation between southeastern and western Alaska (Φst= 0.23, P &lt; 0.0001), but also found significant differentiation at regional and local scales. Rookeries in the Gulf of Alaska, eastern Bering Sea, and eastern Aleutians were distinct from rookeries in the central and western Aleutians (Fst= 0.021, P &lt; 0.0001; Φst= 0.017, P &lt; 0.0001). The location of this split coincides with an oceanographic divergence between continental shelf and ocean basin waters and with differences in sea lion foraging ecology and population trends. A number of rookeries were also significantly differentiated from nearby rookeries (Fst= 0.02–0.025, P &lt; 0.05), signifying substantial female-mediated philopatry, in some cases, at local scales. These findings have important implications for understanding the ecology of Steller sea lions in relation to marine ecosystems and the causes of population declines, and they provide guidance for management, including the identification of management stocks.

Changes in esophageal motility after porfimer sodium photodynamic therapy for Barrett’s dysplasia and mucosal carcinoma

Esophageal dysmotility is common in patients with Barrett's esophagus. Previously we have reported deterioration of esophageal motility after photodynamic therapy (PDT) in a heterogeneous group of patients with esophageal carcinoma. This prospective study in consecutive patients describes changes in motility noted after endoscopic ablation. Forty-seven patients referred to our institution for endoscopic ablation for Barrett's high grade dysplasia or mucosal carcinoma between August 2001 and May 2003 were prospectively evaluated with esophageal manometry before and after porfimer sodium PDT. Six patients did not complete the study. Manometry results were classified as normal, diffuse esophageal spasm, ineffective esophageal motility, or aperistalsis. Abnormal esophageal motility was found in 14 of 47 (30%) patients at study entry ([diffuse esophageal spasm] DES-3, [ineffective esophageal motility] IEM-7, Aperistalsis-4). After PDT, 11 of 41 patients with paired studies experienced a change in manometric diagnosis. Three patients had an improvement in motility, seven a worsening and one changed diagnosis, but did not particularly worsen or improve. No patient developed new aperistalsis. Therefore, abnormal motility was present in 19 of 41 (46%) patients after PDT (DES-2, IEM-14, Aperistalsis-3). There was a statistically significant (P = 0.016) relationship with longer segment Barrett's esophagus and deterioration of function. Baseline abnormalities in motility can occur in patients with Barrett's high-grade dysplasia or mucosal carcinoma. Changes in esophageal function also may occur following photodynamic therapy, but usually are not clinically significant. Worsening in function was more likely to occur in patients with longer segment Barrett's esophagus.

Electronic transport in DNA sequences: The role of correlations and inter-strand coupling

We investigate the electronic properties in sequences of single and double-strand DNA molecules made up from the nucleotides guanine G, adenine A, cytosine C and thymine T. Using a tight-binding formulation we solve the time-dependent Schrödinger equation to compute the spread of initially localized wave packets. We also compute the localization length in finite segments by employing a Green's function recursion method. We compare the results for the genomic DNA sequence with those of two artificial sequences, namely the quasiperiodic Rudin–Shapiro one, which has long-range correlations, and a intra-strand pair correlated DNA sequence. We found that the short-range character of the intra-strand correlations suffices for a quantitative description of the one-electron wave-packet dynamics in the double-strand real DNA sequences. Further, the inter-strand coupling promotes electronic transport over a longer segment.

Eurycleonus talamellii n. sp. of Cleonine weevil from the Moroccan desert (Coleoptera: Curculionidae: Lixinae: Cleonini)

Eurycleonus talamellii n. sp. is described. It is a taxonomic and geographic vicariant of E. gigas (Marseul 1868), from which it mainly differs by the body with less broadened elytra, the vestiture composed of mixed white and brownish scales in irregular patches, the rostrum nearly straight in profile, the antennae with slightly longer segments, the upper margin of the scrobe sinuate and nearly reaching the lower part of the eye. Remarks on ecology, biogeography and phylogenetic relationships are given.Kew words: Curculionidae, Eurycleonus, Eurycleonus talamellii, new species, taxonomy, biogeography, host plants, Morocco

Novel approach to aortic cannulation suturing: tangential suture technique

Pursestring suture for ascending aortic cannulation in open heart surgery that requires cardiopulmonary bypass may cause serious events, especially in patients who have a thin or calcific aorta. We introduce a novel suturing method, called the 'tangential suture technique', and submit our clinical experience. Adult patients undergoing cardiopulmonary bypass were included in this study. Patients in whom the tangential suture technique was applied (Group A; n = 146) were compared with patients in whom the classic pursestring technique was applied (Group B; n = 152). The age (38 +/- 11 years vs 36 +/- 10 years), sex (males 65.1% vs 62.5%) and operation types were similar in both groups. Although the difference was not significant (P > 0.05), subadventitial haematoma occurred more frequently in Group B (13 patients; 8.6%) than in Group A (3 patients; 2.1%). However, none in Group A required opening the adventitia. No aortic dissection was observed in peri- or postoperative periods in either group. In Group B, seven (4.6%) patients required repair by suture after tying of pursestring sutures following decannulation because of bleeding, while none was required in Group A (P = 0.0156). Tangential suture technique allows the needle to take a longer segment from the media layer while decreasing the likelihood of entering the lumen. Because the tract of the suture almost perfectly fits to the needle curve, tissue injury is less, even on fragile aortas, and this ensures more stable closure of the hole when the suture is tied following decannulation. By considering both its theoretical advantages and our clinical experience, we believe tangential suture technique should be preferred to the classic method.

Joint coordination during quiet stance: effects of vision

Stabilization of the center of mass (CM) is an important goal of the postural control system. Coordination of several joints along the human "pendulum" is required to achieve this goal. We studied the coordination among body segments with respect to horizontal CM stabilization during a quiet stance task and the effects of vision on CM stability. Subjects were asked to stand quietly on a narrow wooden block supporting only the mid-foot, with either open (EO) or closed (EC) eyes on separate trials. Instant equilibrium points (IEPs) in the center of pressure (CP) trajectory were determined when the horizontal component of the ground reaction force was zero and the CP data were decomposed into their rambling and trembling components. The joint angle, CM and CP data were divided into short cycles (time-normalized to 100 data points) or longer segments (time-normalized to 1000 data points) of equal length beginning and ending in an IEP. Motor abundance with respect to patterns of joint coordination was evaluated using the uncontrolled manifold (UCM) approach. Here, a UCM is a subspace spanning all joint combinations resulting in a given CM position. All combinations of joint angles that lie within this subspace are equivalent with respect to that CM position while joint angle combinations lying in a subspace orthogonal to the UCM lead to deviation from that CM position. UCM analysis was performed on data organized either across time within longer segments or at each point in time across multiple segments or across multiple cycles. Regardless of method of analysis, most of the variance in joint space was constrained to be within the UCM, preserving the mean CM position in both the EO and EC conditions. Joint configuration variance was significantly higher in the EC than in the EO condition although this increase occurred primarily within the UCM rather than in the orthogonal subspace that would have led to variation of the CM position. These results demonstrate the ability of the control system to selectively "channel" motor variability into directions in joint space that stabilize the CM position. This effect was enhanced when the task was made more challenging in the absence of vision. There was also a significant relationship between joint variance that led to a change in the CM position and, in particular, the rambling component of the CP path, lending some support to the idea that the CNS prescribes a certain stable trajectory of the CP during quiet stance that leads to a small controlled movement of the CM.

Solvent Dependence of PII Conformation in Model Alanine Peptides

Alanine residues in two model peptides, the pentapeptide AcGGAGGNH(2) and the 11mer AcO(2)A(7)O(2)NH(2), have been reported to have substantial PII conformation in water. The PII structure in both peptides is sensitive to solvent. In the presence of the organic solvent TFE, the conformation of the pentamer changes from PII to internally H-bonded gamma or beta turns, while the chain with seven alanines forms alpha helix. The PII structure in the 11mer is more stable than that in the shorter peptide as the TFE concentration increases. For the pentamer, a comparison of short-chain aliphatic alcohols to water shows that the PII content decreases in the order water > methanol > ethanol > 2-propanol, linearly according to empirical scales of solvent polarity. Thus, depending on the extent of local solvation as folding progresses, the peptide backbone as modeled by alanine oligomers shifts from PII to internally H-bonded (gamma or beta turn) conformations and to alpha helix in longer segments. On the other hand, the PII content of AcO(2)A(7)O(2)NH(2) increases significantly in the presence of guanidine, as does that of oligoproline peptides, while detergent sodium dodecyl sulfate (SDS) favors alpha helix in this peptide. The shorter peptide does not show a parallel increase in PII with guanidine.

Genetic counseling in carriers of reciprocal chromosomal translocations involving long arm of chromosome 16.

Families with balanced chromosomal changes ascertained by unbalanced progeny, miscarriages, or by chance are interested in their probability for unbalanced offspring and other unfavorable pregnancy outcomes. This is usually done based on the original data published by Stengel-Rutkowski et al. several decades ago. That data set has never been updated. It is particularly true for the subgroup with low number of observations, to which belong reciprocal chromosomal translocations (RCTs) with breakpoint in an interstitial segment of 16q. The 11 pedigrees from original data together with the new 18 pedigrees of RCT carriers at risk of single-segment imbalance detected among 100 pedigrees of RCT carriers with breakpoint position at 16q were used for re-evaluation of the probability estimation for unbalanced offspring at birth and at second trimester of prenatal diagnosis, published in 1988. The new probability rate for unbalanced offspring after 2 : 2 disjunction and adjacent-1 segregation for the total group of pedigrees was 4 +/- 3.9% (1/25). In addition, the probability estimate for unbalanced fetuses at second trimester of prenatal diagnosis was calculated as 2/11, i.e. 18.2 +/- 11.6%. The probability rates for miscarriages and stillbirths/early deaths were about 16 +/- 7.3% (4/25) and <2% (0/25), respectively. Considering different segment lengths of 16q, higher probability rate (0/8, i.e. <6.1%) for maternal RCT carriers at risk of distal 16q segment imbalance (shorter segment) was obtained in comparison with the rate (0/10, i.e. <4.8%) for RCT at risk of proximal segment imbalance (longer segment). It supports findings obtained from the original data for RCT with other chromosomes, where the probability for unbalanced offspring generally increased with decreasing length of the segments involved in RCT. Our results were applied for five new families with RCT involving 16q, namely three at risk of single-segment imbalance [t(8;16)(q24.3;q22)GTG, ish(wcp8+,wcp16+;wcp8-,wcp16+), t(11;16)(q25;q22)GTG, and t(11;16)(q25;q13)GTG] and two with RCT at risk of double-segment imbalance [t(16;19)(q13;q13.3)GTG, isht(16;19)(q13;q13.3) (D16Z3+,16QTEL013-D19S238E+,TEL19pR-; D16Z3-, D19S238E-,TEL19pR+), and t(16;20)(q11.1;q12)GTG, m ish,t(16;20)(wcp16+,wcp20+;wcp16+,wcp20+)]. They have been presented in details to illustrate how the available empiric data could be used in practice for genetic counseling.

Thermochromic transitions in poly(di-n-hexylsilane) films

The spectra of absorption (77–398 K) and luminescence (5 K) of poly(di-n-hexylsilane) films are studied in relation to the heating of the films above the phase transition temperature. Two new absorption bands in the region of the band of the gauche conformation are found. The position and intensity of these bands depend on the annealing temperature, annealing regime, and sample thickness. These bands are assumed to be associated with the appearance of a liquid crystalline phase in the polymer, which is determined by intermolecular interactions between neighboring polymer chains. The appearance of the liquid crystalline phase in the heat-treated polymer films is confirmed by the increase in their birefringence in comparison with the birefringence of the initial films and by the observation of a stable orientation of an E 7 nematic liquid crystal applied to the surface of an annealed sample. In addition, the absorption spectra of the films cooled after the annealing exhibit many new bands in comparison with the spectra of the initial samples. These bands are associated with the appearance in the polymer of defect states and longer segments as a result of orientation of polymer chains. The appearance of longer segments is consistent with the observation of a long-wavelength band in the luminescence spectra of the annealed samples.

Optimization of Ecg Gating in Quantitative Femoral Angiography

To determine which phase of the heart cycle would yield the highest reproducibility in measuring atherosclerosis-related variables such as arterial lumen volume and edge roughness. 35 patients with hypercholesterolemia underwent select- ive femoral angiography, repeated four times at 10-min intervals. The angiographies were performed with ECG-gated exposures. In angiographies 1 and 2 the delay from R-wave maximum to each exposure was 0.1 s, in angiographies 3 and 4 the delay was 0.1, 0.3, 0.5 or 0.7 s or the exposures were performed 1/s without ECG gating. Arterial lumen volume and edge roughness were measured in a 20-cm segment of the superficial femoral artery using a computer-based densitometric method. Measurement reproducibility was determined by comparing angiographies 1-2 and angiographies 3-4. When measuring arterial lumen volume and edge roughness of a 20-cm segment of the femoral artery, reproducibility was not dependent on ECG gating. In measuring single arterial diameters and cross-sectional areas, the reproducibility was better when exposures were made 0.1 s after the R-wave maximum than when using other settings of the ECG gating device or without ECG gating. The influence of pulsatile flow upon quantitative measurement in femoral angiograms seems to be the smallest possible in early systole, as can be demonstrated when measuring single diameters and cross-sectional areas. In variables based on integration over longer segments, measurement reproducibility seems to be independent of phase.

Optimization of ecg gating in quantitative femoral angiography

To determine which phase of the heart cycle would yield the highest reproducibility in measuring atherosclerosis-related variables such as arterial lumen volume and edge roughness. 35 patients with hypercholesterolemia underwent select- ive femoral angiography, repeated four times at 10-min intervals. The angiographies were performed with ECG-gated exposures. In angiographies 1 and 2 the delay from R-wave maximum to each exposure was 0.1 s, in angiographies 3 and 4 the delay was 0.1, 0.3, 0.5 or 0.7 s or the exposures were performed 1/s without ECG gating. Arterial lumen volume and edge roughness were measured in a 20-cm segment of the superficial femoral artery using a computer-based densitometric method. Measurement reproducibility was determined by comparing angiographies 1-2 and angiographies 3-4. When measuring arterial lumen volume and edge roughness of a 20-cm segment of the femoral artery, reproducibility was not dependent on ECG gating. In measuring single arterial diameters and cross-sectional areas, the reproducibility was better when exposures were made 0.1 s after the R-wave maximum than when using other settings of the ECG gating device or without ECG gating. The influence of pulsatile flow upon quantitative measurement in femoral angiograms seems to be the smallest possible in early systole, as can be demonstrated when measuring single diameters and cross-sectional areas. In variables based on integration over longer segments, measurement reproducibility seems to be independent of phase.