Use Of Noninvasive Testing Research Articles

Abstract 39: Does Higher Use Of Non-invasive Testing Improve the Diagnostic Yield Of Coronary Angiography?

Objective. To examine whether higher use of non-invasive testing with stress testing or cardiac computed tomographic angiography increases the diagnostic yield of elective coronary angiography as assessed by subsequent revascularization. Background. Many patients who undergo elective coronary angiography are found not have obstructive coronary disease, yet prior non-invasive testing is often underused. Increasing the use of non-invasive testing prior to elective coronary angiography may improve its diagnostic yield through better selection of candidates for subsequent coronary revascularization. Methods. Using a complete sample of billing claims from a national health insurer, (Aetna) we identified adults≥35 years who underwent elective coronary angiography from January 1, 2008 to September 30, 2009. We first conducted a patient-level propensity-matched analysis to determine the relationship between non-invasive testing with revascularization. We also conducted a regional-level analysis examining geographic variation in non-invasive testing and revascularization rates across U.S. hospital referral regions (HRRs). Results. Overall, 33,429 out of 62,501 (53.5%) patients who underwent elective coronary angiography had non-invasive testing performed within 90 days, the majority undergoing myocardial perfusion imaging (n=29,634). In a matched propensity analysis that adjusted for patient characteristics, prior non-invasive testing was associated with a modestly lower likelihood of subsequent revascularization within 90 days (10.0% v 11.1%, p<0.0001). Across 241 HRRs, we observed substantial regional variation in the use of non-invasive testing prior to coronary angiography (median 52.5%, range 26.3-84.8%), and subsequent revascularization (median 10.8%, range 0-34.6%). However, regional variation in the non-invasive testing rate explained essentially none of the variation in revascularization rates (adjusted r-squared=0.04). Conclusion. Non-invasive testing prior to elective coronary angiography was not associated with increased revascularization in either patient-level or regional-level analyses. Efforts to improve the diagnostic yield of elective coronary angiography by increasing prior use of non-invasive testing may be limited in real-world settings.

Ischemia-Driven Revascularization

Since the introduction of percutaneous coronary intervention (PCI), the goal of the procedure has been to reduce patient symptoms, improve quality of life, and potentially affect clinical outcomes in specific high-risk clinical scenarios, such as acute myocardial infarction. As coronary intervention techniques and technology have matured, leading to near-complete rates of technical success, physicians, patients, and health policymakers are now often faced with questions around which patient subsets gain the most benefit from the procedure. In this context, some have advocated the broad use of noninvasive testing to demonstrate ischemia in patients with symptoms concerning for obstructive coronary disease. In fact, from the earliest descriptions of percutaneous angioplasty, physicians have looked to demonstrate the impact of percutaneous interventions on objectively measured ischemia from noninvasive testing.1 Article see p 309 Current guidelines recommend that patients considered symptomatic with possible obstructive coronary disease have their care driven by risk assessment.2 This risk assessment is derived from the patient’s baseline comorbidities and cardiovascular risk factors coupled with their symptom complex. Low-risk patients should receive cardiovascular risk reducing therapy and follow-up, intermediate risk patients should undergo noninvasive testing for further refining risk assessment, and high-risk patients should undergo cardiac catheterization. This care pathway starts with an evaluation of the likelihood of obstructive coronary artery disease, uses a combination of optimal medical therapy and, in high-risk patients, defining the coronary anatomy, and ends with symptom relief and improved outcomes when revascularization is driven by ischemic symptoms. With this background, Lin et al3 present a provocative analysis of the outcomes of Medicare patients undergoing elective PCI with or without antecedent stress testing. The authors identified a cohort of 23 877 Medicare beneficiaries undergoing elective PCI from 2003 to 2004, excluding patients with acute myocardial infarction, unstable angina, transferred patients, and patients who …

Non-invasive tests in prediction of liver fibrosis in chronic hepatitis B and comparison with post-antiviral treatment results

The aim of this study was to assess and compare the performance of a series of non-invasive tests to detect fibrosis in patients with chronic hepatitis B (CHB). Seventy-six patients with CHB, whose blood samples were collected and biopsies were done on the same day, were included in this study. Pre-treatment calculations of aspartate aminotransferase to platelet ratio index (APRI), Forn's index, FIB-4, S-index, Shanghai Liver Fibrosis Group's index (SLFG) and Hepascore(®) were done and relations with mild and advanced fibrosis and cirrhosis were assessed. Post-treatment values of APRI, Forn's index, FIB-4, S-index with oral antiviral agents were also investigated. APRI, S-index, SLFG, FIB-4, Forn's index and Hepascore(®) had 0.669, 0.669, 0.739, 0.741, 0.753, 0.780; retrospectively Area Under the Receiver Operating Characteristic Curve (AUROC) for significant fibrosis. APRI, Forn's index, S-index, FIB-4, SLFG, and Hepascore(®) had 0.681, 0.714, 0.715, 0.738, 0.747, 0.777 retrospectively AUROC for advanced fibrosis. APRI, SLFG, FIB-4, Forn's index, S-index, and Hepascore(®) had 0.741, 0.742, 0.768, 0.779, 0.792, 0.824 retrospectively AUROC for cirrhosis. APRI, Forn's index, FIB-4 and S-index were significantly lower in post-treatment group compared with pre-treatment group (P-values: <0.05, 0.001, 0.003, 0.018; respectively). Hepascore(®) showed the best performance to predict significant fibrosis. Our study also suggests that the use of non-invasive test to predict fibrosis in patients with CHB may reduce the need for liver biopsy and may help to monitor the efficacy of treatment.

High frequency of asymptomatic Leishmania spp. infection among HIV-infected patients living in endemic areas for visceral leishmaniasis in Brazil

This study aims at estimating the prevalence of Leishmania infection among HIV-infected patients through the use of non-invasive tests. The study was conducted in three Infectious Diseases Services in two large Brazilian cities, both endemic areas for visceral leishmaniasis. Three hundred and eighty-one asymptomatic patients were enrolled whose ages ranged from 19 to 58 years old; 63.5% were men; mean TCD4+ was 380 cells/μl; and mean viral load was 153800 copies/ml. All individuals were tested for Leishmania infection through: ELISA using crude Leishmania infantum (ELISA), ELISA using the recombinant K39 antigen (rK39), indirect fluorescent antibody test (IFAT) and PCR targeted to kDNA region. The tests’ positivity were: 10.8% (ELISA), 3.9% (IFAT), 0.8% (rK39), 6.3% PCR and 20.2% (overall, at least one positive test), with no statistical correlation between positivity and clinical and laboratorial variables. Concordance among tests was low (Kappa <0.20). Prevalence of Leishmania asymptomatic infection was high in this population, reinforcing the need for attention in the evaluation of HIV patients from endemic areas. New efforts are needed to develop more specific and sensitive tests to diagnose Leishmania asymptomatic infection. Highly active antiretroviral therapy (HAART) seems to have a protective role against disease progression in co-infected individuals.

The SHAPE Guideline: Ahead of Its Time or Just in Time?

In 2006, a grass roots movement called SHAPE (Screening for Heart Attack Prevention and Education) published a novel practice guideline for cardiovascular screening in the asymptomatic at-risk population. It suggested the use of noninvasive tests for subclinical atherosclerosis in cardiovascular risk assessment to target intensified preventive care to those at highest risk. The SHAPE guideline received much attention but not as much support from the "official" medical societies. However, subsequent studies published since 2006 have now provided strong supportive evidence for the strategy spearheaded by the SHAPE guideline. Indeed, the latest guidelines issued jointly by the American Heart Association and the American College of Cardiology have elevated recommendation levels for noninvasive imaging of subclinical atherosclerosis. This change is widely viewed as a significant step toward the SHAPE guidelines. The background for SHAPE and the evidence behind the recommendation to use coronary artery calcium score measured by computed tomography, carotid intima-media thickness and plaque measured by ultrasound, and ankle-brachial index in cardiovascular risk assessment is reviewed in this article.

High Prevalence of Iron Deficiency among Educated Hospital Employees in Switzerland

Iron deficiency is known to cause symptoms such as fatigue, depression and restless legs syndrome resulting in impaired quality of life and working capacity. We sought to examine the iron status of reportedly healthy individuals by a framed study design in 58 highly educated Swiss hospital employees and to compare the use of non invasive tests for assessing iron deficiency (ID). A structured interview was used to assess health status, nutritional intake and potential blood loss, blood counts as well as parameters proposed to diagnose iron deficiency were determined. All subjects felt well and were working at their maximum capacity. The male subjects were neither anaemic nor had decreased iron parameters however 50% (23/46) of the women had a serum ferritin of below 22 μg/L, still 33% (15/46) of the women had a ferritin value below the more stringent cut off value of 15 μg/L. In 15% (7/46) of the women we diagnosed iron deficient anaemia. Red meat consumption correlated with ferritin values as did the menstrual blood loss which was estimated by asking the amount of tampons used. Of the additionally analysed iron parameters only the percentage of hypochromic erythrocytes, soluble transferrin receptor and transferrin values were significantly correlated with ferritin and reached an AUCROC of ≥0.7 indicating good predictive tests. Nevertheless neither soluble transferrin receptor nor transferrin showed diagnostic advantages for the diagnosis of ID compared to ferritin alone or together with erythrocyte parameters. Working in a hospital environment and having access to health education does not seem to correlate with prevention of ID or ID anaemia in female hospital employees.

High Prevalence of Iron Deficiency among Educated Hospital Employees in Switzerland.

Iron deficiency is known to cause symptoms such as fatigue, depression and restless legs syndrome resulting in impaired quality of life and working capacity. We sought to examine the iron status of reportedly healthy individuals by a framed study design in 58 highly educated Swiss hospital employees and to compare the use of non invasive tests for assessing iron deficiency (ID). A structured interview was used to assess health status, nutritional intake and potential blood loss, blood counts as well as parameters proposed to diagnose iron deficiency were determined. All subjects felt well and were working at their maximum capacity. The male subjects were neither anaemic nor had decreased iron parameters however 50% (23/46) of the women had a serum ferritin of below 22 μg/L, still 33% (15/46) of the women had a ferritin value below the more stringent cut off value of 15 μg/L. In 15% (7/46) of the women we diagnosed iron deficient anaemia. Red meat consumption correlated with ferritin values as did the menstrual blood loss which was estimated by asking the amount of tampons used. Of the additionally analysed iron parameters only the percentage of hypochromic erythrocytes, soluble transferrin receptor and transferrin values were significantly correlated with ferritin and reached an AUCROC of ≥0.7 indicating good predictive tests. Nevertheless neither soluble transferrin receptor nor transferrin showed diagnostic advantages for the diagnosis of ID compared to ferritin alone or together with erythrocyte parameters. Working in a hospital environment and having access to health education does not seem to correlate with prevention of ID or ID anaemia in female hospital employees.

Non‐invasive assessment of fibrosis in liver grafts due to hepatitis C virus recurrence

Hepatitis C virus (HCV) infection has become the most common indication for liver transplantation in the United States and Europe. Recurrence of HCV is universal in all liver graft recipients, but the natural history of the disease is variable with some patients displaying slowly progressive liver injury, while approximately 30% become cirrhotic within five yr of surgery. Currently, liver biopsy is the reference standard to assess liver injury in the post-transplant setting. But biopsy is associated with complications such as bleeding and pain, as well as the risk of sampling error and discordance in reporting between histopathologists. Thus, as in the pre-transplant setting, there is increasing attention being drawn to the use of non-invasive tests of liver fibrosis. This review examines the role of non-invasive assessment of hepatic fibrosis in the post-transplant setting including simple tests such as aspartate aminotransferase-to-platelet ratio index, the Benlloch formula, London Transplant Centre score, and finally transient elastography. The authors assess the respective advantages and disadvantages of the tests and consider how non-invasive tests of liver fibrosis can be utilized in the future management of post-transplant HCV infection.

Role of multimodality imaging in ischemic and non-ischemic cardiomyopathy

Chronic heart failure (CHF) is a major and growing problem in the western hemisphere, affecting about 5million patients in the United States. In daily practice patients with left ventricular systolic dysfunction (LVSD) and significant angiographic coronary artery disease (CAD) are felt to have an ischemic cardiomyopathy (ICMP) and those without CAD or mild-moderate CAD out of proportion to the extent of LVSD are felt to have a non-ischemic cardiomyopathy (NICMP). Although invasive coronary angiography is the gold standard for the diagnosis of CAD, recent advances in non-invasive imaging have created multiple options for evaluating ICMP and NICMP. This review details the role of cardiac imaging in the diagnosis of ICMP and NICMP and outlines an algorithm of use of non-invasive tests in asymtomatic LVSD and symptomatic heart failure.

Usefulness of noninvasive tests in nodular regenerative hyperplasia of the liver

The only way to diagnose nodular regenerative hyperplasia (NRH) is liver biopsy. To evaluate in a prospective study the performance of noninvasive liver investigations in patients with NRH. All consecutive patients with NRH who were being followed up in our unit from 2004 to 2007 were included. All biopsy specimens were reanalysed independently to confirm the diagnosis of NRH (classified as certain or probable) and to assess portal or sinusoidal associated fibrosis. All patients had liver stiffness (using FibroScan) and FibroTest measurements. Magnetic resonance imaging (MRI) was performed using two contrast agents (gadolinium-chelate and ferucarbotran). Thirty patients were included (mean age: 53 years). Median liver stiffness value was 7.9 kPa (range: 3.5-16.8), with 63% of the patients having more than 7.1 kPa. No relationship was found between NRH with or without portal hypertension and liver stiffness or Fibrotest. No correlation was found between liver stiffness and portal and/or sinusoidal fibrosis. In patients studied with MRI, 55% had portal hypertension and 9% a diffuse fine-nodular loss of iron uptake after ferucarbotran injection. Liver stiffness and FibroTest values may be increased in NRH patients, with no correlation with portal hypertension or portal and sinusoidal fibrosis. Contrast-enhanced MRI is disappointing in NRH.

Cardiovascular risk factors underestimate atherosclerotic burden in chronic kidney disease: usefulness of non-invasive tests in cardiovascular assessment

Cardiovascular risk scoring (Score) does not specifically address chronic kidney disease (CKD) patients. The aim of our study is to quantify atherosclerosis using carotid ultrasound and ankle-brachial index (ABI) and to assess its additional value in risk scoring. In this cross-sectional, observational study, patients were studied according to a standardized protocol including carotid ultrasound and ABI to determine the atherosclerosis score (AS), ranging from absence of to severe atherosclerosis (AS 0 to AS 3). We included 409 CKD-affected patients (231 on dialysis, 99 in CKD Stages IV-V and 79 in CKD Stages I-III) and 851 subjects with normal renal function. The presence and severity of atherosclerosis was significantly higher in the CKD group than in the controls at every decade of age studied. Among the CKD-affected subjects, the prevalence of carotid plaques was significantly higher in the dialysis group (78.3%) than in the group in CKD Stages I-III (55.6%, P < 0.001). We identified 174 patients at low-intermediate risk. Among them, 110 (63.2%) presented either moderate (AS 2) or severe (AS 3) atherosclerosis. Variables significantly (P < 0.05) and positively related to atherosclerosis were being on dialysis [OR = 3.40, 95% CI (1.73, 6.78) vs CKD Stages I-III], age [OR = 1.08, 95% CI (1.06-1.11)] and C-reactive protein [OR = 1.04, 95% CI (1.01-1.08)]. Conversely, female sex was negatively related to atherosclerosis [OR = 0.40, 95% CI (0.23-0.71), P = 0.002]. The use of carotid ultrasound and ABI identifies atherosclerosis in a population of CKD patients in which risk scoring underestimates atherosclerosis burden.

Laboratory evaluation of inflammatory bowel disease

Recognizing inflammatory bowel disease (IBD) is straightforward when alarm symptoms are present, such as bloody diarrhea and weight loss. When the presentation is subtle or atypical, physicians must determine which patients warrant evaluation for IBD. Appropriate use of noninvasive tests can help identify which patients should undergo further investigation. Currently IBD serologies lack high enough sensitivity and specificity to make them useful as a screening test for distinguishing IBD from other disorders, but they may have a role in classifying subtypes of IBD. Fecal markers seem promising for helping to differentiate IBD from irritable bowl syndrome and for monitoring disease activity. Pharmacogenetically guided dosing is recommended for safe use of thiopurines but ongoing routine laboratory monitoring remains important. Thiopurine metabolite measurement can be useful but may not be needed in all cases. Primary care physicians should continue to rely on routine laboratory tests and clinical suspicion to decide which patients with abdominal pain to refer to a gastroenterologist. Serology panels are not useful for IBD screening as the results may lead to unnecessary procedures. Although fecal markers do show promise as a screening test for IBD, patient resistance to providing stool samples may limit its usefulness in disease monitoring. Thiopurine metabolite levels are best used in conjunction with clinical status and routine laboratory tests to monitor clinical response and adverse events.

Impact of on-site cardiac catheterization on resource utilization and fatal and non-fatal outcomes after acute myocardial infarction

BackgroundPatterns of care for acute myocardial infarction (AMI) strongly depend on the availability of on-site cardiac catheterization facilities. Although the management found at hospitals without on-site catheterization does not lead to increased mortality, little it known about its impact on resource utilization and non-fatal outcomes.MethodsWe identified all patients (n = 35,289) admitted with a first AMI in the province of Quebec between January 1, 1996 and March 31, 1999 using population-based administrative databases. Medical resource utilization and non-fatal and fatal outcomes were compared among patients admitted to hospitals with and without on-site cardiac catheterization facilities.ResultsCardiac catheterization and PCI were more frequently performed among patients admitted to hospitals with catheterization facilities. However, non-invasive procedures were not used more frequently at hospitals without catheterization facilities. To the contrary, echocardiography [odds ratio (OR), 2.04; 95% confidence interval (CI), 1.93–2.16] and multi-gated acquisition imaging (OR, 1.24; 95% CI, 1.17–1.32) were used more frequently at hospitals with catheterization, and exercise treadmill testing (OR, 1.02; 95% CI, 0.91–1.15) and Sestamibi/Thallium imaging (OR, 0.93; 95% CI, 0.88–0.98) were used similarly at hospitals with and without catheterization. Use of anti-ischemic medications and frequency of emergency room and physician visits, were similar at both types of institutions. Readmission rates for AMI-related cardiac complications and mortality were also similar [adjusted hazard ratio, recurrent AMI: 1.02, 95% CI, 0.89–1.16; congestive heart failure: 1.02; 95% CI, 0.90–1.15; unstable angina: 0.93; 95% CI, 0.85–1.02; mortality: 0.99; 95% CI, 0.93–1.05)].ConclusionAlthough on-site availability of cardiac catheterization facilities is associated with greater use of invasive cardiac procedures, non-availability of catheterization did not translate into a higher use of non-invasive tests or have an impact on the fatal and non-fatal outcomes available for study in our administrative database.

AHA/ACCF Scientific Statement on the Evaluation of Syncope

AHA/ACCF Scientific Statement on the Evaluation of Syncope

Combined Use of Noninvasive Tests is Useful in the Initial Diagnostic Approach to a Child with Suspected Inflammatory Bowel Disease

To assess the effectiveness of the combined use of fecal calprotectin (FC), anti-Saccharomyces cerevisiae antibody (ASCA), perinuclear staining antineutrophil antibody (pANCA), small intestinal permeability test (IP), and bowel wall ultrasonography measurement (BWUS) in the diagnostic work-up of children with suspected inflammatory bowel disease (IBD). All children referred for initial assessment of possible IBD were eligible. Patients with symptoms or signs (right-lower quadrant mass, perianal disease, or hematochezia) mandating a complete work-up for IBD were excluded. All enrolled patients underwent a clinical, laboratory, radiographic, and endoscopic evaluation including biopsy examinations. The immunoglobulin (Ig)G and IgA ASCA, IgG pANCA, FC, IP, and BWUS were tested in all patients at the initial assessment. A final diagnosis of IBD was made in 27 patients: 17 Crohn disease and 10 ulcerative colitis. Eighteen children had other gastrointestinal diagnoses (8 functional bowel disorders, 5 food allergy-mediated diseases, 4 infectious enterocolitis, 1 familial Mediterranean fever). In patients with simultaneous abnormal values of FC, BWUS, and ASCA/pANCA, the estimated probability of having IBD was 99.47%. Patients with negative results on all tests had a 0.69% of probability of IBD. The incorporation of noninvasive diagnostic tests into the initial diagnostic approach may avoid unnecessary invasive procedures and facilitate clinical decision-making when the diagnosis of IBD in children is initially uncertain.

Bladder tumor markers beyond cytology: International Consensus Panel on bladder tumor markers

This is the first of 2 articles that summarize the findings of the International Consensus Panel on cytology and bladder tumor markers. The objectives of our panel were to reach a consensus on the areas where markers are needed, to define the attributes of an ideal tumor marker, and to identify which marker(s) would be suitable for diagnosis and/or surveillance of bladder cancer. Our panel consisted of urologists and researchers from Europe, Asia, and the United States who reviewed original articles, reviews, and book chapters on individual bladder tumor markers published in the English language mainly using the PubMed search engine. Panel members also met during 3 international meetings to write recommendations regarding bladder tumor markers. The panel found that the most practical use of noninvasive tests is to monitor bladder cancer recurrence, thereby reducing the number of surveillance cystoscopies performed each year. Markers also may be useful in the screening of high-risk individuals for early detection of bladder cancer. However, more prospective studies are needed to strengthen this argument. Case-control and cohort studies show that several markers have a higher sensitivity to detect bladder cancer. However, cytology is the superior marker in terms of specificity, although some markers in limited numbers of studies have shown specificity equivalent to that of cytology. Our panel believes that several bladder tumor markers are more accurate in detecting bladder cancer than prostate-specific antigen (PSA) is in detecting prostate cancer. However, bladder tumor markers are held to a higher standard than PSA. Therefore, use of bladder tumor markers in the management of patients with bladder cancer will require the willingness of both urologists and clinicians to accept them.

Predicting Perioperative Cardiac Risk

Cardiovascular complications are the major cause of perioperative morbidity and mortality of patients undergoing major vascular surgery. This is related to the frequent presence of an underlying coronary artery disease. This paper reviews the pathology of perioperative cardiac complications and cardiac risk assessment and risk reduction strategies. Guidelines of the American College of Cardiology and American Heart Association for the evaluation of cardiac risk for noncardiac surgery may provide the necessary framework for the assessment and management of patients undergoing major vascular surgery. Based on the American College of Cardiology and American Heart Association guidelines and data from contemporary studies, patients without risk factors are considered to be at low risk and do not require additional evaluations for coronary artery disease. Patients with 1 or 2 cardiac risk factors represent an intermediate-risk group for perioperative cardiac complications. If beta-blockers are prescribed, the probability of cardiac complications is low and there is no need for further noninvasive testing. Patients with 3 or more risk factors are at high risk for cardiac complications and the use of noninvasive testing may help further refine cardiac risk based on the presence and absence of test-induced myocardial ischemia. beta-Blockers should be prescribed to all patients, and coronary revascularization should be reserved for high-risk patients who have a clearly defined need for revascularization independent of the need for major vascular surgery.

Diagnostic tests for childhood Helicobacter pylori Infection: Invasive, Noninvasive or Both?

Diagnostic tests for childhood Helicobacter pylori Infection: Invasive, Noninvasive or Both?

Introduction

Avian osteoporosis has been recognized as a problem in the laying hen industry for at least 45 years. The onset of this disease in individual hens decreases bird welfare, eggshell quality, and egg production by the flock but also increases the incidence of broken bones and lameness. Webster presents an overview of the welfare implications of osteoporosis in laying hens. This author discusses the perception of pain by birds, and relates the lesions associatedwith osteoporosis to the degree of pain perceived by the bird. Attention is also given to humane handing and disposition of spent hens.The large demand for Ca for eggshell formation compounds the inability of actively laying hens to deposit new structural bone. The symposium paper presented by Whitehead reviews basic avian bone biology, with special reference to the factors involved in development and prevention of excessive structural bone loss in laying hens.Medullary bone is a unique form of labile bone found in egg-laying birds; potential methods to optimize medullary bone reserves and utilization by the hen are presented.Estrogen plays an important role in the regulation of Ca metabolism in laying hens. Beck and Hansen discuss the metabolic functions of estrogen in the laying hen, and address the topic of changes in estrogen synthesis and receptor numbers as the hen ages. As in humans, simple nutritional interventions are of limited use in preventing avian osteoporosis. Therefore, a deeper understanding of the factors that regulate metabolism in laying hens is required.Because of the serious implications for laying hen productivity and welfare, much research over the years has been conducted into the causes and prevention of osteoporosis. Measurements of production such as egg numbers and eggshell quality have been used to indirectly assess the effects of dietary, pharmaceutical, or management treatments on Ca metabolism of laying hens. Direct measurement of the skeletal health of laying henswas almost always conducted postmortem. Traditionally, measurements of avian bone quality involved sacrificing a portion of the population at various times throughout or at the end of a trial and conducting destructive tests on the bones. These tests included measurement of specific bonemass and volumetric density, breaking strength, and bone ash andmineral measurements. Although many important fundamental discoveriesweremade using these techniques, the availability of modern analytical techniques and equipment has spurred an increase in the use of noninvasive testing of bone quality of laying hens. Fleming and co-workers present results of their studies using quantitative ultrasound, in which the speed of sound through a bone is dependent upon the density of the specific location on the bone in question (amplitude-dependent speed-of-sound ultrasound). Hester et al. offer details on their use of dual-energy x-ray absorptiometry to assess bone density of entire bones. X-rays of 2 distinct energies are passed through the bone and recorded, and the attenuation of each of the energies by the bone is used to calculate a two-dimensional radiographic density. Korver et al. communicate their work with quantitative computed tomography. This technique involves passing an x-ray at numerous angles through a fixed point on a bone. The resultant cross-sectional image allows calculation of a true volumetric mineral density as well as spatial distribution of bone mineral at that specific crosssection of bone.The previous 3 papers compare each of the newer noninvasive

Utilidad de la arteriografía con tomografía computarizada helicoidal multicorte en el diagnóstico de la estenosis preoclusiva de la carótida interna cervical

Distinction between near-occlusion and occlusion of the internal carotid artery (ICA) is relevant because patients can benefit from a surgical treatment in the first case. Digital subtraction angiography (DSA) is the best neuroimaging technique for its diagnosis but the possibility of related neurologic complications suggests the use of non-invasive tests. Ultrasound (US) and magnetic resonance angiography (MRA) have been proposed as alternative techniques of diagnosis. But these can provoke an erroneous diagnosis when a near occlusion of ICA is present. Multislice helicoidal computed tomographic angiography (MHCTA) can play a role in these situations. Case 1: patient diagnosed of occlusion of the left ICA by cervical US. Cerebral magnetic resonance suggested severe stenosis of intracavernous ICA. MHTCA showed carotid permeability. Case 2: patient diagnosed by cervical US of near occlusion and of occlusion/pseudoocclusion by enhanced RMA. MHCTA showed filiform patency of the cervical ICA. Case 3: a cervical US diagnosed moderate stenosis of the right ICA and severe of the left. Transcranial Doppler suggested near occlusion of the right ICA. MHTCA confirmed near occlusion of the right ICA. MHCTA correctly diagnosed near occlusion in three patients in which minimally invasive techniques had discrepancies. MHTCA is a new diagnostic technique whose lack of dependence of flow makes a good alternative to confirm findings of US of the cervical ICA.