bluuebunny/crossref_metadata_2025 huggingface dataset:
THERMOLUMINESCENCE DATING OF A CRUCIBLE FRAGMENT FROM AN EARLY TIN PROCESSING SITE IN TURKEY
Authors: VANDIVER P. B. , KAYLOR R. , FEATHERS J. , GOTTFRIED M. , YENER K. A. , HORNYAK W. F. , FRANKLIN A.
Published: August 2007

Archaeological exploration in the Taurus mountains at Göltepe in south‐central Turkey has uncovered a site indicating the presence of extensive tin ore mining and smelling operations The most recent find of smelting crucible fragments allowed for a thermoluminescence‐hased age determination spanning a late fifth to early third millennium BC date. This result is consistent with a number of radiocarbon dates derived for charcoal also found at the site. The importance of this site relates to the possible tin production and subsequent trade with southwestern Asia which would have provided this otherwise scarce ingredient to bronze technology in that area. This date is directly for crucible material and thus confirms the antiquity of tin smelting at Göltepe.
ESTIMATION OF THE BULK COMPOSITION OF FINE‐GRAINED MEDIA FROM MICROCHEMICAL AND BACKSCATTER‐IMAGE ANALYSIS: APPLICATION TO BISCUIT WASTERS FROM THE BOW FACTORY SITE, LONDON*
Authors: OWEN J. V. , DAY T. E.
Published: August 2007

Microprobe and digitized electron‐backscatter image data reveal that eighteenth‐century Bow porcelain consists of a silica polymorph(s) (25–43 vol. %), a calcium phosphate phase (42–55%) with homogeneous and stippled textural variants, and a silicon‐, aluminium‐, and calcium‐rich, former melt phase represented by discrete domains (14–20%) and micron‐scale blebs that occupy 20–70% of the stippled calcium phosphate. Bulk compositions calculated from these data are deficient in calcium phosphate components and more siliceous than those determined by microprobe analysis of fused powders of the same samples. This reflects difficulties in determining representative values for the composition and volume of the melt phase, and underscores the limitations of the method where applied to media containing compositionally‐ or texturally‐heterogeneous phases.
MODIFIED MAHALANOBIS FILTERS FOR GROUPING POTTERY BY CHEMICAL COMPOSITION*
Authors: BEIER T. , MOMMSEN H.
Published: August 2007

A statistical procedure for grouping pottery in provenance studies by chemical data is presented, which now is routinely in use in our laboratory. It is based on the Mahalanobis filter method and X2 ‐statistics, and can be used for both establishing groups and assigning single sherds to already known groups, thus replacing principal components analysis or cluster analysis and avoiding their problems in grouping pottery. The new method is able to consider correlations, uncertainties of measurement and constant shifts of the data in case of dilution. In particular, considering dilution effects results in both a better assignment to and separation of reference groups and is also equivalent to the compositional data approach, if log‐transformed data are used. Other distortions of data (e.g., mixing of clays) can also be considered.
THE BEGINNINGS OF ISLAMIC STONEPASTE TECHNOLOGY*
Authors: MASON R. B. , TITE M. S.
Published: August 2007

A multidisciplinary programme of research on Islamic pottery has been focused on questions of the dating, provenance and technology of Islamic pottery. One particular question has been the development of stonepaste, a material made primarily of crushed quartz with added frit‐glass and clay. The combination of the different approaches of this study has revealed early foundations for the technology in ninth‐century AD Iraq, apparently originating in the clay ceramic rather than the ‘Egyptian faience’ tradition. Subsequent and final practice developed in tenth‐ and eleventh‐century AD Egypt. This technology becomes the primary body for all fine Islamic ceramics.
METHODS OF ENGRAVING MESOPOTAMIAN QUARTZ CYLINDER SEALS
Authors: SAX M. , MEEKS N. D.
Published: August 2007

Cylinder seals, which were produced more or less continuously for about 3000 years in Western Asia, were worked with designs in intaglio. In this paper we report the results of an investigation into the techniques used to engrave seals composed of quartz. Our observations were made with a binocular microscope and supplemented by examination of impressions with a scanning electron microscope. A range of factors was considered, including shape in plan, topography, surface texture and orientation of features. In this way four basic techniques of engraving have been recognized. They have been tentatively interpreted as micro‐chipping, filing, wheel‐cutting and drilling.
FINE WARE FROM LOCRI EPIZEPHIRI: A PROVENANCE STUDY BY INDUCTIVELY COUPLED PLASMA EMISSION SPECTROSCOPY
Authors: MIRTI P. , CASOLI A. , BAGNASCO M. BARRA , ANCONA M. C. PREACCO
Published: August 2007

Fifty‐six sherds of fine ware from Locri Epizephiri were analysed by inductively coupled plasma optical emission spectroscopy (ICPOES) and flame emission spectroscopy (FES). The sherds had been excavated on the archaeological areas of Marasà Sud, Centocamere and San Cono, and represent local and imported products from the seventh to the second century BC. The samples were dissolved by fusion with lithium metaborate and analysed for nine elements (Al, Fe, Ca, Mg, Ti, Mn, Sr, Ba and Cr) by ICPOES, while Na and K were determined by FES. The analytical data were subjected to hierarchical agglomerative clustering and principal components analysis to classify the sherds into compositional groups. The results obtained indicated that Corinthian, Attic and Ionian products or imitations may be classified in a few separate groups, while most local products are found in a unique, large group.
COMPOSITIONAL VARIABILITY IN COLOURLESS ROMAN VESSEL GLASS
Authors: BAXTER M. J. , COOL H. E. M. , HEYWORTH M. P. , JACKSON C.
Published: August 2007

A statistical re‐analysis is undertaken of 118 inductively coupled plasma spectrometry analyses of Romano‐British glass specimens found in excavations at Colchester. There are four vessel types present, some of which are associated with chronologically distinct periods. Previous research has suggested little difference in the mean composition of different types. The present paper shows that there are interesting differences in the variation of compositions within types, with some showing much greater compositional stability then others. Some possible models to explain this phenomenon are discussed.
RADIOCARBON DATES FOR BEESWAX FIGURES IN THE PREHISTORIC ROCK ART OF NORTHERN AUSTRALIA
Authors: NELSON D. E. , CHALOUPKA G. , CHIPPINDALE C. , ALDERSON M. S. , SOUTHON J. R.
Published: August 2007

Accelerator mass spectrometry radiocarbon ages have been taken for a test suite of small samples of material removed from some of the ‘beeswax’art figures found in rock shelters in northern Australia. The results indicate that we can reliably date this unique form of rock art with no noticeable damage. We had not expected to find figures of any great antiquity, and so we were surprised to find that the ages obtained spanned the time period from the recent past to about 4000 BP.
MIDDLE HOLOCENE PERIODICITIES IN RAINFALL INFERRED FROM OXYGEN AND CARBON ISOTOPIC FLUCTUATIONS IN PREHISTORIC TROPICAL ESTUARINE MOLLUSC SHELLS
Authors: KENNETT D. , VOORHIES B.
Published: August 2007

Stable oxygen and carbon isotopic ratios in modern and archaeological estuarine mollusc shells, Polymesoda radiata, change in accordance with seasonal salinity fluctuations in the Acapetahua estuary located on the Pacific coast of southern Mexico. This region receives −3000 mm of precipitation annually, most during a wet season between April and October. The changing flux of fresh water and organic detritus into the estuary causes large changes in the oxygen and carbon isotopic composition of the estuarine waters and in the carbonate precipitated by P. radiata. Oxygen isotopic ratios in the shells of molluscs collected by late Archaic period populations (5000–4000 BP) in this region indicate that patterns of rainfall were similar to today. Modern shells, however, exhibit much more negative carbon isotopic values than observed in prehistoric shells. This change may be associated with the input of modern fertilizers into the estuary.
AN ASSESSMENT OF BACK‐SCATTERED ELECTRON PETROGRAPHY AS A METHOD FOR DISTINGUISHING MEDITERRANEAN OBSIDIANS
Authors: KAYANI P. I. , MCDONNELL G.
Published: August 2007

The recent application by Burton and Krinsley (1987) of back‐scattered electron (BSE) petrography to obsidians from sources located in the south‐western United States established that this method can effectively resolve and characterize included micro‐crystalline phases that have proven difficult to analyse by optical thin‐section microscopy. In the first extension of their original study, we have examined, using BSE petrography, obsidians from island sources located in the Mediterranean, including sources known to have been exploited in prehistory. Because of the kinetic contrasts on their crystallization, these microcrystalline phases reflect the magmatic history of the obsidian, providing information about superheating, supercooling, sub‐solidus processes, and other phenomena. This information is of significance for the chemical analysis of Mediterranean obsidians and also as the basis for a powerful alternative to existing non‐destructive analytical methods for the sourcing of archaeological and art‐historical obsidian.
HISPANO‐MORESQUE POTTERY PRODUCTION OF THE FOURTEENTH‐CENTURY WORKSHOP OF TESTAR DEL MOLÍ (PATERNA, SPAIN)
Authors: MOLERA J. , GARCÍA‐VALLÉS M. , PRADELL T. , VENDRELL‐SAZ M.
Published: August 2007

Excavation of Testar del Molí, the only workshop found in the Manises‐Paterna area, revealed the existence of a fourteenth‐century ceramic workshop covering the remains of the thirteenth‐century workshop. This study is concerned with the fourteenth‐century production, and forthcoming papers will connect both epochs following the findings of current excavations. The chemical and mineralogical characterization of the ceramic production of this workshop shows the presence of three groups of ceramic pastes which could also be distinguished by, and, thus, related to, their daily use. The raw materials found in the excavation have also been mineralogically and chemically characterized, and a model of possible mixtures of raw materials has also been developed in order to determine their possible use in the manufacture of the pottery previously characterized.
CHEMICAL AND MINERALOGICAL ANALYSES OF GALLO‐ROMAN WALL PAINTING FROM DIETIKON, SWITZERLAND
Authors: BÉARAT H.
Published: August 2007

Around 90 samples of Roman wall painting dating from the first to the third century AD were analysed using different analytical techniques: X‐ray diffraction, X‐ray fluorescence, infrared spectrometry, scanning electron microscopy, energy dispersive spectrometry, optical microscopy and physico‐chemical tests. The identified pigments are: ash, calcite, carbon black, celadonite, cinnabar, Egyptian Blue, glauconite, goethite, hematite and red lead. Pigment mixtures were used to get other colours such as brown, pink or purple. Three types of plaster were used: a first, and most dominant, with river sand, a second with crushed tile for damp places and a third, to which cinnabar was exclusively applied, was prepared with crushed calcite crystals.
France in Shakespeare's Henry V
Authors: Womersley David
Published: August 2007

‘Messires, what newes from Fraunce, can you tell! Still warres, warres.’ John Eliot, Ortho‐Epia Gallica. Eliots Fruits for the French (1593), sig. A3r
History and culture in a provincial centre: a universal chronicle from Renaissance Rimini
Authors: Bornstein Daniel
Published: August 2007

The Cronaca universale of Gaspare Broglio is well known to local historians, who have long used it as a precious source of information about the Malatesta of Rimini and their political adventures. This essay reads it instead for clues to the cultural formation and intellectual interests of its author. In what he read and what he chose to include in his chronicle, this Sienese‐born chronicler in the service of a lord of the Romagna displayed an eclectic interest in both classical and chivalric subjects, interests that he shared with his Malatesta masters and the Po valley nobility to which they belonged. Broglio's cultural formation and tastes were broadly characteristic of a class, not narrowly typical of a locale. Like others of his class, Broglio circulated widely in the service of a variety of masters. This circulation loosened any attachment he, and others of his class, might have had to a particular place, while fostering a sense of belonging to a supra‐local cadre of people of similar background, experience, duties, and skills. Thus, his training and outlook may fairly be taken as typical of an entire group of people: that cadre of moderately well‐educated members of the lesser nobility who served the princes of Italy in military, diplomatic, and administrative capacities and whose most distinguished representative, born right about the time Broglio left off writing his chronicle, was Baldassare Castiglione.
The Impact of Surplus Distribution on the Risk Exposure of With Profit Life Insurance Policies Including Interest Rate Guarantees
Authors: Kling Alexander , Richter Andreas , Ruß Jochen
Published: August 2007

Abstract

This article analyzes the numerical impact of different surplus distribution mechanisms on the risk exposure of a life insurance company selling with profit life insurance policies with a cliquet‐style interest rate guarantee. Three representative companies are considered, each using a different type of surplus distribution: a mechanism, where the guaranteed interest rate also applies to surplus that has been credited in the past, a slightly less restrictive type in which a guaranteed rate of interest of 0 percent applies to past surplus, and a third mechanism that allows for the company to use former surplus in order to compensate for underperformance in “bad” years. Although at the outset all contracts offer the same guaranteed benefit at maturity, a distribution mechanism of the third type yields preferable results with respect to the considered risk measure. In particular, throughout the analysis, our representative company 3 faces ceteris paribus a significantly lower shortfall risk than the other two companies. Offering “strong” guarantees puts companies at a significant competitive disadvantage relative to insurers providing only the third type of surplus distribution mechanism.
The Determinants of Private Debt Holdings: Evidence From the Life Insurance Industry
Authors: Pottier Steven W.
Published: August 2007

Abstract

Life insurers hold the majority of private debt. Lenders in the private debt market must have the ability to evaluate the credit quality of borrowers and to perform ongoing risk monitoring. The purpose of this study is to examine the determinants of private debt holdings in the life insurance industry. The results suggest that larger insurers, insurers with higher financial quality, mutual insurers, publicly traded insurers, insurers facing stringent regulation, and insurers with greater cash holdings are more prevalent lenders in the private debt market.
Efficiency and Demutualization: Evidence From the U.S. Life Insurance Industry in the 1980s and 1990s
Authors: Jeng Vivian , Lai Gene C. , McNamara Michael J.
Published: August 2007

Abstract

This article examines the efficiency changes of U.S. life insurers before and after demutualization in the 1980s and 1990s. We use two frontier approaches (the value‐added approach and the financial intermediary approach) to measure the efficiency changes. In addition, we use Malmquist indices to investigate the efficiency and productivity change of converted life insurers over time. The results using the value‐added approach indicate that demutualized life insurers improve their efficiency before demutualization. On the other hand, the evidence using the financial intermediary approach shows the efficiency of the demutualized life insurers relative to mutual control insurers deteriorates before demutualization and improves after conversion. The difference in the results between the two approaches is due to the fact that the financial intermediary approach considers financial conditions. The results of both approaches suggest that there is no efficiency improvement after demutualization relative to stock control insurers. There is, however, efficiency improvement relative to mutual control insurers when the financial intermediary approach is used.
Results of Right Coronary Artery Endarterectomy With or Without Patchplasty
Authors: Göl M. Kamil , Yilmazkaya Bayram , Göksel Sabahattin , Şener Erol , Mavitaş Binali , Taşdemir Oǧuz , Bayazit Kemal
Published: August 2007

Abstract We report preoperative and early postoperative findings of 286 coronary bypass patients operated between 1988 and 1998 who had endarterectomy and/or patchplasty to the right coronary artery. In this retrospective study there were 61 cases with only saphenous vein patchplasty to the right coronary artery (patch group), 57 patients who underwent endarterectomy and patchplasty (open‐patch group), and 229 patients having closed endarterectomy to the right coronary artery (closed group). A group of 150 patients having a saphenous vein graft to the right coronary artery without endarterectomy were chosen as a control group. Gender, age, family history, smoking history, diabetes, hyperlipidemia, hypertension, nature of the angina, severity of the coronary artery disease, left ventricular functions, preoperative rhythm, and electrocardio‐graphic patterns were evaluated for their effect on early mortality among groups. No significant difference was detected. Positive inotropic and mechanical support need was higher in the closed group at the end of the operation and in the intensive care unit. Duration of cardiopulmonary bypass and clamp time was higher in the open‐patch group. Atrial fibrillation in the early postoperative period was more frequent in the patch and closed groups. Complete atrioventricular block development and the need for a pacemaker were higher in the open‐patch and closed groups. Non‐Q wave myocardial infarction was more frequent in the closed group. Mortality rates were higher in the open‐patch and closed groups. We conclude that endarterectomy to right coronary artery should be avoided if possible, and patchplasty with saphenous vein should be preferred.
Reduction of Blood Loss and Transfusion Requirements After Coronary Artery Bypass Grafting: Similar Efficacy of Tranexamic Acid and Aprotinin in Aspirin‐treated Patients
Authors: Bernet Franziska , Carrel Thierry , Marbet German , Skarvan Karl , Stulz Peter
Published: August 2007

Abstract Background: In patients with coronary artery disease, continuation of aspirin may reduce the incidence of unstable angina and preoperative myocardial infarction before surgery, but the risk of perioperative bleeding may be increased.

Methods: The efficacy of aprotinin and tranexamic acid (TXA) was examined in a prospective, randomized, double‐blind trial involving 56 patients scheduled for coronary artery bypass grafting and who received aspirin 100 mg/day until the day of the operation. Group I received high‐dose aprotinin whereas group II received 10 g of tranexamic acid (TXA) over 20 minutes before sternotomy. Heparinization during cardiopul‐monary bypass was controlled with HDTT (high‐dose thrombin time) to eliminate interference of aprotinin on ACT (celite activated clotting time). Postoperative blood loss and transfusion requirements were registered during the first 24 hours.

Results: The demographics, coagulation, and intraoperative parameters were similar in both groups. Postoperative blood loss (aprotinin 840 mL /24 hours, TXA 880 mL/24 hours, p = 0.481). and transfusion requirements (2.18 units/patient in the aprotinin group, 2.11 units/patient in the TXA group) were not remarkably different between the two regimen protocols. No perioperative myocardial infarction, pulmonary embolism, cerebrovascular event, or other thrombotic events were observed.

Conclusions: In this trial, we were not able to demonstrate any difference in postoperative bleeding in patients pre‐treated with aspirin after high‐dose aprotinin or TXA. From a practical point of view, TXA is safe, less expensive than aprotinin, and easy to handle, and can be recommended in patients pre‐treated with aspirin to improve postoperative hemostasis.
Heart Transplantation in Perspective
Authors: Keon W. J.
Published: August 2007

Abstract Heart disease remains one of the leading causes of death in the western world. In the 35 years since the first human heart transplants, cardiac transplantation has become established as the therapeutic option of choice in the management of terminal cardiac failure. Since 1981, the introduction of cyclosporin for immunosuppression has dramatically increased cardiac transplantation. However, several obstacles limit further utilization, including limited availability of donor hearts, limited ischemic time tolerated by donor hearts, and chronic rejection. Research is underway into donor heart preservation and new immunosuppressant drugs in an effort to increase donor organ availability. Due to these constraints, alternative therapies are under development. More than 2,000 circulatory assist devices have been implanted with > 25% used as a bridge to heart transplantation. The University of Ottawa Heart Institute began the first Canadian implantation of circulatory assist devices in 1986 and has implanted 23 total artificial hearts and 23 ventricular assist devices. The Heart Institute is also developing a totally implantable electro‐hydraulic ventricular assist device (EVAD) for long‐term mechanical support outside the hospital. Another alternative being evaluated for clinical use is xenotransplantation. The major obstacle for widespread use of clinical xenotransplantation remains graft rejection, and fundamental research is ongoing to address hyperacute and delayed xenograft rejection. While cardiac tran‐plantation is the most effective treatment of terminal heart failure, limited donor hearts compel us to rely on alternatives. In the future, the research underway on xenotransplantation and mechanical circulatory assist devices will provide new options for the clinical treatment of terminal cardiac failure.
Mechanical Circulatory Devices for the Treatment of Heart Failure
Authors: Mussivand Tofy
Published: August 2007

Abstract Background: During the last four decades substantial efforts have been made in the development of effective mechanical circulatory devices. Since the first clinical utilization in the 1960s, the field has gone from the stage of clinical experimentation to that of a valid and effective heart failure treatment alternative. Experience gained during the short‐term use of these devices, typically as a bridge to cardiac transplantation, has led to increased expectations of devices capable of long‐term or permanent support to be used as a permanent treatment for end‐stage heart failure patients. This article reviews the history, current state of the art, and future of the field of mechanical circulatory devices. Methods: Mechanical circulatory devices can be classified into three major categories: (1) total artificial hearts, (2) pulsatile ventricular assist devices, and (3) nonpulsatile ventricular assist devices. The most widely used devices have been the pulsatile ventricular assist devices with more than 5,800 reported cases, whereas the use of total artificial hearts has been limited to less than 350 reported cases. Nonpulsatile devices have been used clinically, but only in short‐term cases (i.e., hours and days), whereas the pulsatile devices have been used in the long‐term application, with patients supported for weeks, months, and in a small number of cases, years. The technological evolution of these devices has gone from large, extra‐corporeal systems designed to keep the patient alive in the intensive care unit (ICU) until a donor organ could be found, to portable devices that allow the patient to be mobilized outside of the hospital setting. Results: The clinical experience with mechanical circulatory devices as a bridge to cardiac transplantation has saved the lives of thousands of patients. Exciting new research discoveries related to recovery of native heart function during extended circulatory support have provided new hope for many more patients. Additional research efforts currently underway are being tested at various laboratories around the world and will soon provide the next generation of systems. These new systems will offer the recipients an unparalleled quality of life with minimal limitations on daily activities. The progress in this field has reached the point where circulatory support will soon be considered a valid long‐term or permanent therapy and an elective to transplantation.
Mitral Valve Replacement in the Presence of Massive Posterior Annular Calcification
Authors: Lin Pao‐Yen , Kan Chung‐Dann , Luo Chwan‐Yau , Yang Yu‐Jen
Published: August 2007

Abstract Replacement of the mitral valve in the presence of extensive calcification of the posterior annulus is a technical challenge. The heavily calcified annulus often results in difficulties of seating the prosthesis and later periprosthetic leakage. A radical calcium de‐bridement may leave a friable and thin annulus that contributes to the risks of prosthesis dehiscence and ventricular perforation. To avoid technical difficulties and associated catastrophic complications, we devised a new technique of mitral valve replacement that allows a surgeon to implant a prosthesis securely. This technique involves inserting a larger single tilting disc mechanical valve (Medtronic Hall disc) with intra‐atrial anchorage over the posterior sector of the calcified annulus, orienting the working (major) orifice of the mechanical valve anteriorly, and thereby tilting the lesser occluder segment of the disc upward into the atrium and away from the calcification in diastole. By utilizing this method, we have successfully performed mitral valve replacement in two patients who exhibited massive calcification of the posterior mitral annulus. Postoperative transeosophageal echocardiography showed excellent hemodynamic performance of the implanted valves. We therefore recommend this simple, safe, and time‐saving procedure as a feasible method to deal with this surgical dilemma. (J Card Surg 1999; 74:266–269)
New Technique of Posterior Mitral Annuloplasty
Authors: Izumoto Hiroshi , Kiyoyuki Eishi , Ohuchi Shingo , Kawazoe Kohei
Published: August 2007

Abstract We have developed a new technique of mitral annuloplasty applicable in patients with rheumatic mitral regurgitation. This technique is designed to advance anteriorly the posterior annulus and leaflet and to gain more coaptation area. Technical details of this procedure are presented. (J Card Surg 1999;14:270–272)
One‐Stage Repair of Interrupted Aortic Arch and Aortopulmonary Window with an Autologous Arterial Flap
Authors: Chiu Ing‐Sh , Wu Shye‐Jao , Lee Meng‐Luen
Published: August 2007

Abstract Interrupted aortic arch associated with an aortopulmonary window is a rare congenital malformation that requires an early diagnosis and surgical treatment to avoid irreversible pulmonary vascular changes. We describe herein successful one‐stage repair in a neonate without the use of pericardium or other prosthetic material. Use of a transaortic approach permitted both accurate planning of the appropriate size of pulmonary trunk flap and also facilitated easy repair of the aortopulmonary septal defect. The growth potential of both great arteries was optimized. (J Card Surg 1999; 14:306–309)
Detection and Localization of an Intracardiac Bullet and Pellet by Echocardiography
Authors: SARMA RADHA J. , PRAKASH RAVI , MANDAL ASHIS K. , FLEMING ARTHUR W.
Published: August 2007

We found echocardiography to be useful for detecting and precisely localizing intracardiac bullets and pellets. The characteristic reverberations produced by these metallic objects are of diagnostic value in patients with such penetrating missile injuries.
Echocardiography and the Evolution of Cardiac Imaging
Authors: SKORTON DAVID J.
Published: August 2007

Imaging techniques are among the most commonly used diagnostic approaches to patients with heart and vascular diseases. Recently, sophisticated new methods of imaging the heart, great vessels, and pulmonary and peripheral vasculature have rapidly evolved. This evolution has occurred due to technological developments, research imperatives, and clinical needs. Current cardiac imaging methods give superb information on cardiac structure and function. The newer approaches to imaging promise to supply additional information on myocardial perfusion, metabolism, and tissue characteristics. The explosion of research and development in cardiac imaging gives the clinician and investigator a wealth of choices for evaluation of the heart. This wide array of choices requires that practicing physicians and echocardiogra‐phers develop a broad perspective on the relative efficacy, costs, and drawbacks associated with each of the diagnostic imaging procedures.
Doppler Echocardiographic Quantification of Stenotic Valvular Lesions
Authors: RICHARDS KENT L.
Published: August 2007

The individual performing quantitative measurements of valve stenosis must always be vigilant of the most common errors made in assessing stenotic lesions:

1. Underestimation of pressure gradients across stenotic valves can lead to false‐negative diagnoses. A Doppler angle greater than 25 degrees or the failure to insonate the high‐velocity region are common causes.

2. Over‐ and underestimation of pressure gradients is possible when angle correction is used.

3. Mistaken sample volume position (such as detection of high‐velocity mitral regurgitation when assessing aortic stenosis) can lead to overestimation of stenotic pressure gradients.

4. Improper instrument settings can lead to inaccurate velocity measurements.

We have entered an area in which Doppler and imaging echocardiography are capable of producing accurate hemodynamic data on patients with stenotic valve lesions. Such data can be used to make surgical decisions or to avoid further, sometimes more definitive, diagnostic tests. We must use care to assure that the measurements that we report are appropriate and accurate. It is appropriate to integrate the Doppler and imaging echocardiographic data with information obtained from history, physical exam, ECG, and chest roentgenogram to provide the most accurate assessment of the severity of the valve lesion(s). It is also important to interpret the quality of a study and report the likelihood that the study is complete and the results are highly accurate or that the study was difficult and may be incomplete.
Echocardiographic Contrast in Two‐Dimensional Echocardiography: New Applications for an Old Technique?
Authors: CHRISTENSEN CARL W. , REEVES WILLIAM C.
Published: August 2007

Although Gramiak and Shah1 first introduced the technique of using contrast enhanced two‐dimensional echocardiography in 1968, it has seen a resurgence of new and varied applications. Three of the areas of interest are in the use of microbubble enhanced contrast agents to evaluate: (1) regional myocardial blood flow; (2) regional myocardial function; and (3) myocardial ischemic areas and infarct size. Whether these new approaches will have applications and value in the clinical laboratory is still a matter of conjecture. The objective of this review is to briefly summarize the potential uses and the advantages and disadvantages of each application.
Quantification of Acute Aortic Regurgitation by Color Doppler Flow in an Experimental Animal Model
Authors: REEVES WILLIAM C. , MOVAHED ASSAD , HSIA PENG WIE , ROSE GREGORY C. , JOLLY STANLEY R.
Published: August 2007

Color Doppler flow studies were performed on ten anesthetized open‐chest dogs. Acute aortic regurgitation was created in the dogs by a special valve‐spreading catheter. The magnitude of valvular regurgitation was determined by aortic electromagnetic flow recordings of regurgitant fraction. Arbitrarily‐designated grades of aortic regurgitation: mild (4%‐10%), moderate (11%‐30%), and severe (>30%) were assigned on the basis of electromagnetic flow. We attempted to obtain studies of varying degrees of AR in each animal. Mean regurgitant fraction for the three grades were 6.8 ± 0.6% (n = 11), 22.0 ± 2.4% (n = 7), and 40.4 ± 2.5 (n = 20), respectively (each P <0.05). By color Doppler flow assessment, the ratio of regurgitant jet height to the left ventricular dimension at the junction of the left ventricular outflow tract and the aortic annulus (JH/LVOH) was measured in each study. AR was classified by Doppler as grade I (mild), 1%‐24%; II (moderate), 25%‐64%; and III (severe), ≥65% jet height/left ventricular outflow tract height. Color Doppler flow correlated well with flowmeter assessment of regurgitant fraction. Color Doppler flow tests had a calculated sensitivity of 88%, specificity of 83%, and predictive value of 85% for significant (moderate + severe) aortic regurgitation. Our data support the concept that this method of color Doppler flow assessment provides a quantitative noninvasive evaluation of aortic regurgitation.
Combined Femoral Pseudoaneurysm and Arteriovenous Fistula: Diagnosis by Doppler Color Flow Mapping
Authors: SU CLAUDE T. , NANDA NAVIN C. , PINHEIRO LUIZ , PLUMB VANCE J. , GROSS GARY
Published: August 2007

This case report is the first to describe a combined femoral pseudoaneurysm and arteriovenous fistula resulting from a cardiac catheterization, diagnosed by color Doppler.
Epicardial Coronary Artery Imaging
Authors: ISRINGHAUS HELMUT
Published: August 2007

Intraoperative high‐frequency echocardiography with a 12‐MHz linear scanner is a diagnostic tool for imaging coronary morphology. This method was used in 630 vascular sections in 112 operations. The vessel diameter (80%), the absence of stenoses (77%), the condition of the vessel wall (39%), and the localization of occlusions (14%) were examined. Fifty vessels not visible to the eye (8%) could be echocardiographically imaged. Anastomoses were examined 45 times (7%). By using high‐frequency echocardiography, intraoperative decisions could be acted upon immediately in 46 operations (41%).
Intravascular and Intracardiac Ultrasound Imaging: Current Research and Future Directions
Authors: PANDIAN NATESA G. , WEINTRAUB ANDREW , SCHWARTZ STEVEN L. , KUMAR ROHIT , KUSAY BRENDA S. , KATZ SARAH E. , ARONOVITZ MARK , UDELSON JAMES , KONSTAM MARVIN A. , SALEM DEEB N. , KREIS ANDREAS
Published: August 2007

Intravascular and intracardiac ultrasound imaging is a newly emerging catheter‐based imaging modality with considerable promise. This review article presents the rationale behind attempts at developing intravascular imaging methods, the design features of intravascular instrumentation, the knowledge obtained with in vitro studies, the in vivo experience in humans, and the potential applications of intravascular imaging in arterial atherosclerosis. The feasibility of pulmonary artery imaging and the potential applications of intracardiac echocardiography are discussed. Finally, future directions in intravascular imaging are outlined.
Plaque Characterization of Atherosclerotic Coronary Arteries by Intravascular Ultrasound
Authors: BARTORELLI ANTONIO L. , POTKIN BENJAMIN N. , ALMAGOR YARON , KEREN GAD , ROBERTS WILLIAM C. , LEON MARTIN B.
Published: August 2007

Intravascular ultrasound provides cross‐sectional images of arteries and enables accurate delineation of lumen dimensions and wall structure. Moreover, ultrasound characterization of atherosclerotic plaque subtypes may have important implications in determining the natural history and the clinical outcome of patients with coronary artery disease. The reliability of intravascular ultrasound to differentiate plaque morphology subtypes was studied in 60 coronary segments excised from 33 coronary arteries obtained from 17 patients at necropsy. Ultrasound was performed with a 25‐MHz transducer mounted on the distal end of a rigid probe that was rotated manually inside the lumen artery. Plane film radiography was also performed to establish the presence of calcific deposits. A total of 82 histologic transverse sections corresponding to 82 ultrasound imaging sites were studied from the 60 coronary segments. Of the first 54 images, 36 were fibrous plaques and yielded dense homogenous echo reflections, 6 had discrete areas of lipid that were less echogenic and 12 had calcific deposits that cast echo‐free shadows beyond areas of intense echo reflections. The predictive accuracy of evaluating plaque composition in the remaining 28 ultrasound imaging sites was 96%. Thus, anatomical structure of coronary arteries and composition of atherosclerotic lesions can be assessed accurately with intravascular ultrasound and may have potential for better understanding of the atherosclerotic process and provide guidance to interventional procedures.
Accuracy of Doppler Ultrasound in Evaluating Changes of Left Ventricular Diastolic Properties
Authors: LIN SHOA‐LIN , TAK TAHIR , KAWANISHI DAVID T. , RAHIMTOOLA SHAHBUDIN H. , CHANDRARATNA P. ANTHONY N.
Published: August 2007

In order to evaluate the effect of an increase in preload caused by contrast medium (Renografin‐75) on Doppler echocardiographic indices of left ventricular diastolic properties, left ventricular pressure using a catheter tip micromanometer and pulsed‐Doppler measurement of transmitral flow signals were measured simultaneously in 15 patients with coronary artery disease pre‐ and post‐left ventricular angiography. After left ventricular angiography, changes in indices determined from left ventricular pressure were significant: left ventricular end‐diastolic pressure increased from 17 ± 2 mmHg to 24 ± 2 mmHg (mean ± SE) (P < 0.001), maximum ‐dP/dt increased from 1,129 ± 63 to 1,307 ± 90 mmHg/sec (P < 0.005), and time constant decreased from 73 ± 2 to 67 ± 1 msec (P < 0.01). Changes in Doppler‐derived indices were also significant: A/E ratio decreased from 0.99 ± 0.08 to 0.81 ± 0.07 (P < 0.01), peak velocity of early diastolic filling increased from 0.61 ± 0.03 to 0.79 ± 0.03 M/sec (P < 0.01), and deceleration rate increased from 3.1 ± 0.2 to 4.6 ± 0.2 M/sec2 (P < 0.01). Changes in Doppler echocardiographic indices (DR, acceleration half time, deceleration half time, and A/E ratio) were accompanied by changes in time constant and maximum ‐dP/dt after left ventricular angiography. However, the correlations between changes in hemodynamic indices and changes in Doppler echocardiographic indices were poor (r = 0.06 to 0.67). We conclude that changes in Doppler indices of left ventricular diastolic properties are not satisfactory for evaluating changes in left ventricular end‐diastolic pressure, time constant, and maximum ‐dP/dt which reflects the limitation of these presently available parameters to assess diastolic function.
Impaction of the Ventricular Septum by Porcine Mitral Valves
Authors: GRAHAM SUSAN P. , PAULSEN WALTER H.
Published: August 2007

Impaction of the ventricular septum by a porcine mitral valve was noted by echocardiography in three asymptomatic and one symptomatic patient. When compared to 42 patients without septal impaction, no single echocardiographic feature predicted impaction. The detection of impaction in asymptomatic patients was more common than expected and does not imply valve dysfunction. Close follow‐up is indicated for potential prosthesis or myocardial complications.
Parameters and Standardization in Obstetric Doppler
Authors: GILL ROBERT W.
Published: August 2007

Obstetric Doppler is still largely empirically based, although possible clinical applications are already under examination. This article examines some of the basic instrumentation and hemodynamic issues — which physiological parameters would we ideally like to assess, and what can we do in practice with current Doppler instrumentation? It is shown that the rate of blood flow and the flow resistance are two of the most basic hemodynamic parameters. It is possible to estimate the flow rate with (specialized) Doppler equipment, but there is no method available at present to measure the flow resistance. Analysis of the blood velocity waveform provides some information concerning flow resistance, as long as it can be assumed that other factors that might affect the waveform have not deviated significantly from the norm. Practical considerations in choosing the instrumentation and designing the examination protocol are discussed, and issues of quality control are emphasized.
Origin and Site of the Tricuspid Regurgitant Jet Determined by Color Flow Imaging in Ebstein's Anomaly
Authors: TAK TAHIR , NIBLEY CARL , GUNAWARDANE KUMAR , REID CHERYL , YOUNG GUILLERMO , RAHIMTOOLA SHAHBUDIN H. , CHANDRARATNA PREMINDRA A.N.
Published: August 2007

Fifty patients with tricuspid regurgitation due to a variety of causes including rheumatic heart disease, pulmonary hypertension, atrial septal defect, and tricuspid valve endocarditis (group 1); and seven patients with Ebstein's anomaly of the tricuspid valve (group 2) had color Doppler flow imaging performed. The position of the tricuspid annulus and the site of origin of the turbulent tricuspid regurgitant jet were determined from the apical four‐chamber view. The site of origin of the tricuspid regurgitant jet was at or within 0.5 cm of the level of the tricuspid annulus in all group 1 patients. In contrast, all patients in group 2 had tricuspid regurgitant jets that originated deep in the right ventricle and at a considerable distance from the tricuspid annulus (3.8 ± 1.4 cm, mean ± SD). The distance from the origin of the tricuspid regurgitant jet to the tricuspid annulus was measured and expressed as a ratio to that of the distance from the right ventricular apex to the tricuspid annulus in groups 1 and 2. This ratio was 0.94 ± 0.2 in group 1 and 0.61 ± 0.10 in group 2 patients. In conclusion, the tricuspid regurgitant jet originates at or near the level of the tricuspid annulus except in patients with Ebstein's anomaly. Origin of the tricuspid regurgitant jet distal to tricuspid annulus is a clue to the diagnosis of Ebstein's anomaly and is particularly helpful in those patients in whom the displaced tricuspid leaflet cannot be convincingly demonstrated on the two dimensional echocardiogram.
New Direction of Biplane Transesophageal Echocardiography with Special Emphasis on Real‐Time Biplane Imaging and Matrix Phased‐Array Biplane Transducer
Authors: OMOTO RYOZO , KYO SHUNEI , MATSUMURA MAKOTO , ADACHI HIDEO , MARUYAMA MASANOBU , MATSUNAKA TOSHIYUKI
Published: August 2007

This article reports on the technical aspects of an online real‐time biplane transesophageal echocardiographic imaging system and of a single‐matrix, phased‐array transducer capable of transverse and longitudinal scanning.
Pediatric Transesophageal Color Flow Imaging 1990: The Long and Short of It
Authors: RITTER SAMUEL B.
Published: August 2007

Noninvasive cardiac imaging has dramatically altered the practice of cardiology, specifically, the pediatric patient with congenital heart disease over the past decade. Since the introduction of transesophageal echocardiography nearly 15 years ago, addition of high‐resolution cross‐sectional imaging combined with Doppler color flow mapping has provided a new window to examine the heart. Recently, miniaturization of the transesophageal probe to “pediatric‐size” has enabled its use in the smallest of infants to add significantly to the assessment of congenital heart malformations. Most recently, addition of a longitudinal‐plane probe to the already‐existent, transverse‐plane probe has made biplane transesophageal echocardiography a reality with significant additional information being provided by orthogonal images of the cardiac structures. We used these probes in complementary fashion in 30 studies performed in 23 patients ages 1 day to 12 years with a mean of 35 months, weighing 2.6–40 kg (mean 12.4 kg). These studies were performed in the operating room, intensive care unit, cardiac catheterization laboratory, and outpatient department. Limitations of single‐plane, transverse transesophageal echocardiography were overcome using the longitudinal‐axis pediatric probe: left and right ventricular outflow tracts, distal pulmonary arteries, and all of the interventricular and atrial septa were easily visualized. Its use in the operating room and postoperative cardiac intensive care unit for continuous ventricular monitoring in otherwise‐inaccessible patients also provided critical information. Transesophageal echocardiography in infants and small children is a valuable “noninvasive” imaging technique which, with addition of complementary longitudinal‐plane views, offers important additional information regarding congenital heart malformations and their repair.
The Relevance of Transcranial Doppler to Ischemic Stroke Outcome
Authors: MARINONI MARINELLA , GINANNESCHI ANDREA , MACUCCI MARCO , INZITARI DOMENICO
Published: August 2007

To assess the value of transcranial Doppler examination for the early prognosis of ischemic stroke, we examined 24 patients (15 males and 9 females, mean age 66.8 ± 9.3 years) with hemispheric cerebral infarction, within 6 hours of stroke onset. Of these 24 patients, 22 were evaluated on the Canadian Neurological Scale, the Toronto Stroke Scale, and the Barthel Index on days 60 and 120. Mean flow velocity in the middle cerebral artery on the lesion side was measured and values outside the range 30 to 80 cm/sec were rated abnormal. Two of nine patients with normal flow velocity died compared to five of the 13 patients with abnormal values. Four of the seven remaining patients in the former group made a full recovery compared with none of the remaining eight patients in the latter group (P < 0.05). Neurological and functional status measured on the scales used on days 60 and 120 were also significantly better in the group with normal flow velocity. Early transcranial Doppler may prove useful in predicting the outcome of hemispheric infarction in the acute phase of cerebral ischemia. (ECHOCARDIOGRAPHY, Volume 8, September 1991)
Anomalous Mitral Arcade: Echocardiographic and Color Flow Findings
Authors: PACILEO GIUSEPPE , RUSSO MARIA GIOVANNA , CALABRO RAFFAELE
Published: August 2007

A patient with surgically confirmed anomalous mitral valve arcade was noninvasively studied. Two‐dimensional echocardiography clearly visualized the “arcade” shape and Doppler color flow mapping was useful in assessing hemodynamics. (ECHOCARDIOGRAPHY, Volume 8, November 1991)
Biplane Transesophageal Echocardiography Utilizing Transverse and Sagittal Imaging Planes
Authors: RICHARDSON S. GEOFFREY , WEINTRAUB ANDREW R. , SCHWARTZ STEVEN L. , SIMONETTI JANET , CALDEIRA MARJORY E. , PANDIAN NATESA G.
Published: August 2007

The recent development of biplane transesophageal probes equipped with both transverse plane and sagittal plane imaging transducers allows a more complete examination of cardiac and aortic anatomy than is possible with conventional single plane transesophageal instruments. While the imaging planes used in transverse plane transesophageal imaging have been standardized, several different approaches have been suggested for the orientation and display of the newer sagittal plane images. An accepted display convention for the transverse and sagittal plane images would ease interpretation of the multiple complex images obtained during the biplane transesophageal examination. In this article, the different transverse plane and sagittal plane echocardiographic images that may be acquired during the biplane transesophageal examination are described and correlated with cardiac anatomy. A method for image display orientation is suggested that is most consistent with that previously used for the single plane transesophageal examination. (ECHOCARDIOGRAPHY, Volume 8, May 1991)