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At least 541 records · Page 30Linked to original sources
PubMed1992

Clinical nuclear imaging techniques for the diagnosis and evaluation of acute myocardial infarction.

The use of nuclear imaging techniques allows the accurate detection of myocardial infarction, determination of the impact of infarction on ventricular performance, assessment of the myocardial salvage with thrombolysis, identification of preserved regional metabolism in jeopardized myocardial segments, and the elucidation of inducible reversible ischemia requiring aggressive therapeutic intervention. Assessment of myocardial salvage after thrombolysis or revascularization can be accomplished with serial perfusion imaging. Infarct-avid imaging with Tc-99m-PYP can be used to rapidly determine the size and location of the acute transmural myocardial infarction. In the future, however, the improved image quality and diagnostic accuracy of immunoscintigraphy with antimyosin antibodies may supplant PYP imaging. Studies of global ventricular function can be performed at rest, or with multiple interventions using portable scintigraphic devices. The measurement of the dynamic response of left ventricular ejection fraction over time shows promise for risk stratification. As yet, there has been no comprehensive comparison of the relative predictive value of metabolic imaging parameters, perfusion/antibody uptake mismatch, Tl-201 redistribution, or ejection fraction response data. Such a comparison could optimize the diagnostic algorithm for post-infarction damage assessment and risk stratification.

Coronary Disease↗
PubMed1995

Site-directed bronchoalveolar lavage and transbronchial biopsy in HIV-infected patients with pneumonia.

We have assessed the diagnostic value of site-directed bronchoalveolar lavage (BAL) and combined transbronchial biopsy (TBB) in 29 HIV-infected patients with localized pneumonia, in whom a previous BAL was nondiagnostic and in whom improvement did not occur with empiric antibiotic therapy. All patients but three had a CD4 cell count < 100/microliters. A definite diagnosis could be reached in 26 of 29 (90%) individuals, including 24 pathogens. Neither the radiologic pattern nor the type of Pneumocystis carinii (PC) prophylaxis could predict the positivity of either one of these two diagnostic procedures. Site-directed BAL alone allowed a diagnosis in infection in eight (28%) cases. TBB alone led to diagnosis in eight (28%) cases, including three PC and two toxoplasma gondii, undiagnosed by the site-directed BAL. Both techniques were positive and in agreement in 10 (34%) cases. The majority of the diagnosis led to a specific treatment. Therefore, the patients' survival was positively altered by the procedure. In conclusion, the performance of site-directed BAL and combined TBB markedly optimizes the diagnostic yield of each of these procedures performed separately in HIV-infected patients with localized pneumonia.

Adult↗
PubMedDate not supplied

A priori risk and optimal test accuracy in prenatal diagnostics.

The prevalence of fetal chromosome anomalies rises exponentially with the age of the pregnant woman. The risk of fetal anomalies can be specified using biochemical screening tests such as the triple test. This test substantially reduces the number of amniocenteses and proportionally the number of procedure-related miscarriages. However, disadvantages of the triple test include the utility loss of pregnant women who, following a false-negative test result, do not undergo amniocentesis and bear a disabled child as well as the intangible cost of a false-positive triple test. This paper employs a decision-analytic model to reveal the evaluation of this tradeoff, which is implicitly fixed by policy recommendations for a direct amniocentesis at maternal age of 35. It then determines the optimal level of cutoff risk for the triple test, and derives comparative static results: the optimal test accuracy decreases with increasing a-priori risk and increases with a rise in the miscarriage risk and in the woman's preference for detecting an affected fetus as compared to avoiding a miscarriage of an unaffected fetus. These results are in contrast to current clinical practice, where the cutoff of the triple test usually remains fixed.

Adult↗
PubMed1996

Diagnosis of Helicobacter pylori infection.

A number of diagnostic tests have been developed for the detection of H. pylori. Diagnostic techniques can be divided into invasive and noninvasive methods. The invasive methods require upper gastrointestinal endoscopy and involve culture of gastric biopsy specimens, examination of stained biopsies and detection of urease activity in the biopsies themselves. In addition, we have developed endoscopic diagnosis of H. pylori infection in gastric mucosa using phenol red dye-spraying. The noninvasive methods include urea breath test and serological techniques. Although there has been considerable improvement in the techniques, a combination of at least two different techniques should be used in order to optimize the diagnostic yield. We recommend the use of one rapid test in the combination. The rapid urease test, cytology and the phenol red dye-spraying endoscopy give results available before the patient leaves the endoscopy suite.

Helicobacter Infections↗
PubMed2006

MR imaging of the spine at 3T.

There are many advantages and challenges associated with 3T imaging of the spine. The increase in SNR allows for optimization of diagnostic quality and improved clinical efficiency. PI techniques merge well with high-field technology, which minimizes many of the challenges that are associated with 3T systems. The increase in chemical shift, pulsatile flow, and susceptibility artifact can be mediated with manipulation of imaging parameters. One major challenge that plagued 3T imaging of the spine was the decrease in fluid contrast that was associated with the lengthened T1 relaxation times. This has been resolved essentially for non-contrast spine imaging by using T1 FLAIR, which delineates soft tissue, CSF, disc, and bone interfaces exquisitely well. The optimal postcontrast T1 sequence may not exist yet. Clinical experience dictates that with a combination of T1 FLAIR with or without fat saturation (in one plane) and T1 FSE(in the other plane) no significant enhancing pathology will be missed. Despite the challenges, 3T imaging of the spine provides many improvements over 1.5T systems. These advances can be maximized by use of still evolving technologies and pulse sequence designs.

Artifacts↗
PubMed2006

Use of tissue Doppler imaging to guide tube current modulation in cardiac multidetector computed tomographic angiography.

In multidetector computed tomographic coronary angiography, strategies to minimize effective radiation dose (ERD) are urgently needed. Prospective tube current modulation (TCM) allows a decrease in ERD, although it may limit reconstruction options. We sought to determine if tissue Doppler imaging (TDI) by echocardiography could predict an optimal phase for multidetector computed tomography and be used to guide TCM. Echocardiographic studies were performed in 94 patients immediately before multidetector computed tomography (83% men; mean 60 +/- 11 years of age, mean body mass index 27.7+/-4.1 kg/m2) and identified the most quiescent phase of the cardiac cycle within the atrioventricular groove. In 40 patients, prospective TCM was programmed according to TDI (TCM(TDI) group); 54 patients underwent multidetector computed tomography without TCM (no-TCM). In 25 patients assigned to the TCM(TDI) group, multidetector computed tomograms were correlated with invasive quantitative coronary angiograms to ensure maintenance of diagnostic accuracy. Optimal phase determined by TDI was 71 +/- 11%, with a distinct bi-modal distribution. Compared with no-TCM, effective radiation dose was decreased by 42% in the TCM(TDI) group (6.6 +/- 1.2 vs 11.4 +/- 2.2 mSv, p < 0.0001). Only 8 segments (3%) were unevaluable due to motion artifact. In 296 segments, sensitivity, specificity, and positive and negative predictive values to detect lesions > 50% by multidetector computed tomography were 92%, 94%, 65%, and 99%, respectively. There was good correlation between quantitative coronary angiography and multidetector computed tomography for absolute degree of stenosis (r = 0.70, p < 0.0001). In conclusion, TDI is a useful tool to guide prospective TCM in multidetector computed tomography. ERD in multidetector computed tomography may be significantly decreased using this technique while maintaining excellent image quality.

Cardiac Catheterization↗
PubMed1993

Diagnosis of primary tuberculosis in children by amplification and detection of mycobacterial DNA.

Standard microbiologic techniques were compared with a rapid diagnostic method based on the amplification by polymerase chain reaction (PCR) of a fragment of the IS6110 insertion element (present in multiple copies in the Mycobacterium tuberculosis genome) for the detection of M. tuberculosis in specimens obtained from children diagnosed as having primary tuberculosis on clinical grounds. Two (n = 7) or three (n = 15) gastric aspirates were obtained from the 22 children with primary tuberculosis. All specimens were negative for mycobacteria by acid-fast staining and culture. When DNA was purified from the clinical specimens and aliquots of each sample were amplified in duplicate, 15 of 59 (25%) specimens gave at least one positive result. Increasing beyond two the number of times that samples were tested did not appreciably improve sensitivity. Testing multiple samples from the same individual increased the diagnostic yield. Thus, when three different samples from the same subject were tested two times each, two or more positive results were obtained from 9 of 15 children with primary tuberculosis but 0 of 17 control subjects. Samples from children with symptoms, recent contact with patients with active tuberculosis, vesicular tuberculin responses, or abnormal chest radiographs were more frequently positive than those from patients whose only manifestation of tuberculosis was a positive (but not vesicular) tuberculin response. Thus, M. tuberculosis DNA can be detected by PCR in gastric aspirates of many children with primary tuberculosis, despite that specimens from these patients are negative by culture. Multiple samples must be tested to optimize the diagnostic yield.

Bacteriological Techniques↗
PubMed2001

Screening for acute DVT: optimal utilization of the vascular diagnostic laboratory.

Since the introduction of venous duplex ultrasound scanning in the early 1980s, many articles have been published describing its use for the diagnosis of deep vein thrombosis (DVT) in symptomatic and asymptomatic high-risk patients. Although technological advances have improved B-mode imaging and Doppler signal processing in the last 2 decades, duplex ultrasonography still has limitations in the diagnosis of acute DVT. Besides those that are technological in nature, there also are limitations because of a lack of standards from one vascular laboratory to another. Studies vary according to the ultrasound techniques used, diagnostic criteria, number and types of patients studied, reimbursement guidelines, and compliance with established standards. Duplex examinations vary from unilateral to bilateral, limited to complete, proximal to distal, and imaging only to imaging combined with Doppler techniques. The sensitivity and specificity of duplex ultrasound for identifying symptomatic proximal DVT are in excess of 95%; however, these drop considerably for asymptomatic DVT in high-risk patients and in patients with isolated calf vein thrombosis. Nevertheless, the utilization of the vascular laboratory to screen for acute DVT in all patients, regardless of the limitations in specific populations, is increasing steadily, whereas reimbursement and the number of technologists available to perform these examinations is decreasing. To achieve optimal utilization of the vascular laboratory, national standards in the form of clinical pathways using evidence from the literature need to be developed and utilized. In addition, referring physicians need to be educated on the accuracy and limitations of duplex ultrasound scanning to avoid both overtreatment and undertreatment of acute DVT.

Acute Disease↗
PubMed2004

Primary pulmonary non-Hodgkin's lymphoma.

BACKGROUND: Primary pulmonary non-Hodgkin's lymphoma is a very rare neoplasm. It is represented most commonly by marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type. Although there have been a few reviews of this lymphoma, clinical features, diagnostic procedure, optimal management and prognostic factors have not been well defined. METHODS: We reviewed the medical records of 24 patients who were pathologically and clinically diagnosed as primary pulmonary lymphoma between September 1995 and June 2003. RESULTS: There were 13 patients with MALT lymphoma and two with MALT lymphoma accompanied by large B-cell lymphoma, seven with diffuse large B-cell lymphoma and two with anaplastic large cell lymphoma. Half the patients were asymptomatic at presentation; 46% had respiratory symptoms and 16.7% had B-symptoms. Initial radiological findings were variable including nodules, masses, infiltrates or consolidation. The majority of patients (66.7%) needed surgical approaches (open thoracotomy or video-assisted thoracoscopy) for definite diagnosis. Bronchoscopy was performed in 83%, but only 30% showed a diagnostic yield. The 13 patients with MALT lymphoma were treated with a variety of modalities such as observation, surgery and single or combination chemotherapy, and combination chemotherapy was administered to 11 patients with non-MALT lymphoma regardless of surgery. The overall survival rate at 3 years for all 24 patients was 86% with a median follow-up of 32 months. CONCLUSION: Although this entity of lymphoma appears to have a good prognosis, further clinical experience and long-term follow-up are needed to identify prognostic factors.

Bronchoscopy↗
PubMed2005

Circulating human antibodies against dengue NS1 protein: potential of recombinant D2V-NS1 proteins in diagnostic tests.

The dengue virus (DV) causes one of the most important arthropod-borne human viral diseases throughout the tropical and subtropical countries. However, the morbidity and mortality of DV infections could be reduced with an early hospitalization care and a rapid risk identification of developing the dengue haemorrhagic fever (DHF). The nonstructural glycoprotein 1 (NS1) has been pointed as a reagent for immune-assay diagnostic test optimization. To evaluate this potential, recombinant DV2-NS1 proteins (rNS1) were produced from Escherichia coli (NS1EC) and insect cells (NS1IC) expression. The tests were performed by analysis of a human serum panel reacted against different rNS1 forms. The results demonstrated high correspondence between the DV positive sera and the assay results using native or refolded forms of either NS1IC or NS1EC. Also, the IgG and IgM anti-rNS1 level profiles showed distinct distribution, depending on protein form and disease status. However, the IgM anti-rNS1 reactions did not show sensibility to detect the DV in primary infections. The data obtained from the paired serum samples reactivity comparison suggested a heterogeneous human immune response and absence of correspondence between the IgG and IgM profile levels. Moreover, a patient with negative reference test could be detected by specific IgG anti-rNS1 assays presented here. Therefore, these results sustain the usefulness of dengue nonstructural proteins, in particular the NS1, in diagnostic tests as a complementary reagent.

Animals↗
PubMedDate not supplied

Friction of the gliding surface. Implications for tendon surgery and rehabilitation.

Finger flexor tendon rehabilitation has come a long way, but further advances are possible. Ideally, a healing tendon should move, but under the minimum load necessary to achieve motion. It is possible to design suture repairs that minimize the friction between tendon and sheath while simultaneously maintaining adequate strength to provide a wide margin of safety during therapy. A looped, four-strand modified Kessler repair is a good example of this type of high-strength, low-friction repair. At the same time, rehabilitation methods can also be optimized. A new modified synergistic motion protocol is described in which wrist flexion and finger extension is alternated with wrist and metacarpophalangeal joint extension and finger interphalangeal joint flexion. Based on evidence from basic science studies, the authors hypothesize that this new protocol will deliver more effective proximal tension on the tendon repair than either passive flexion/active extension or synergistic protocols, and may be useful in patients who are not ready for, or are not reliable with, active motion or place and hold protocols. The scientific basis for these new methods is reviewed, and the concept of the "safe zone" for tendon loading, in which tendon motion occurs without gapping of the repair site, is developed.

Biomechanical Phenomena↗
PubMed2006

[Diagnostic strategies in cases of suspected periprosthetic infection of the knee. A review of the literature and current recommendations].

Reliable confirmation of periprosthetic infection after total knee arthroplasty is a diagnostic challenge. The present work reviews published data evaluating the available diagnostic tools. Erythrocyte sedimentation rate and C-reactive protein serum levels are relatively sensitive methods with rather low specificity towards periprosthetic infection and are mainly applied to exclude infection. Studies evaluating scintigraphic methods--especially white cell scans--provide inconsistent data with varying accuracy. Consequently, white cell scans cannot be recommended as standard methods. Immunoscintigraphy with antigranulocyte antibodies and FDG-PET scans demonstrated promising results with particularly high sensitivities, but have to be validated in larger studies. Microbiological evaluation of joint aspirates proved high specificity for periprosthetic infection. However, an average of 20% of infected cases remained undetected. Nevertheless, aspiration is widely recommended for preoperative isolation of the infecting organism. Intraoperative frozen sections demonstrated excellent specificity with good sensitivity. The real accuracy of intraoperative culture and permanent histology cannot be determined due to the missing golden standard; however, a combination of both methods is recommended to define the final diagnosis. Large studies validating both methods and criteria for the final diagnosis of periprosthetic infection are necessary to optimize the diagnostic algorithm.

Arthroplasty, Replacement, Knee↗
PubMed1975

Early mother-infant reciprocity.

By three weeks of age, the human neonate demonstrates behaviours which are quite different with an object and with a human interactant. He also demonstrates an expectancy for interaction with his caregiver which has clearly defined limits, as demonstrated behaviourally. In microanalysis of videotape, we saw regularly a set of interactive behaviours which were demonstrable in optimal face-to-face interaction between infants and their mothers. All parts of the infant's body move in smooth circular patterns as he attends to her. His face-to-face attention to her is rhythmic with approach-withdrawal cycling of extremities. The attention phase and build-up to her cues are followed by turning away and a recovery phase in a rhythm of attention-non-attention which seems to define a cyclical homeostatic curve of attention, averaging several cycles per minute. When she violates his expectancy for rhythmic interaction by presenting a still, unresponsive face to him, he becomes visibly concerned, his movements become jerky, he averts his face, then attempts to draw her into interaction. When repeated attempts fail, he finally withdraws into an attitude of helplessness, face averted, body curled up and motionless. If she returns to her usual interactive responses, he comes alive after an initial puzzled period, and returns to his rhythmic cyclical behaviour which has previously characterized their ongoing face-to-face interaction. This attentional cycling may be diagnostic of optimal mother-infant interactions and seems not to be present in more disturbed interactions.

Attention↗
PubMed2006

What are the risks from medical X-rays and other low dose radiation?

The magnitude of the risks from low doses of radiation is one of the central questions in radiological protection. It is particularly relevant when discussing the justification and optimization of diagnostic medical exposures. Medical X-rays can undoubtedly confer substantial benefits in the healthcare of patients, but not without exposing them to effective doses ranging from a few microsieverts to a few tens of millisieverts. Do we have any evidence that these levels of exposure result in significant health risks to patients? The current consensus held by national and international radiological protection organizations is that, for these comparatively low doses, the most appropriate risk model is one in which the risk of radiation-induced cancer and hereditary disease is assumed to increase linearly with increasing radiation dose, with no threshold (the so-called linear no threshold (LNT) model). However, the LNT hypothesis has been challenged both by those who believe that low doses of radiation are more damaging than the hypothesis predicts and by those who believe that they are less harmful, and possibly even beneficial (often referred to as hormesis). This article reviews the evidence for and against both the LNT hypothesis and hormesis, and explains why the general scientific consensus is currently in favour of the LNT model as the most appropriate dose-response relationship for radiation protection purposes at low doses. Finally, the impact of the LNT model on the assessment of the risks from medical X-rays and how this affects the justification and optimization of such exposures is discussed.

Dose-Response Relationship, Radiation↗
PubMed1988

The psychometric structure of the Wechsler Memory Scale in comparison to the WAIS-R in a low-IQ clinical population.

The psychometric structure of the Wechsler Memory Scale (WMS) and its relationship to the revised Wechsler Adult Intelligence Scale (WAIS-R) were studied in an outpatient population of 103 individuals with low Full Scale IQ scores (M = 71). We found that the age correction of the WMS scores gave memory quotients (WMQ) equivalent to WAIS-R FSIQ scores, but our findings also raised problems of interpretation. If the usual rule of thumb of a 12-point discrepancy between the MQ and the FSIQ were applied, the WMS might be relatively insensitive to memory impairment in this low-IQ clinical population, in which more numerous cases of impairment could be expected. Principal components analysis of the WMS raw scores and three WAIS-R scores included as reference variables yielded five orthogonal factors: Attention/Concentration; Visual Reproductions; New Verbal Learning; Well-learned Semantic Knowledge; and Intelligence. We argue that raw scores on the WMS should be reported to optimize possible diagnostic specificity and to align the WMS with experimental and clinical research in various types of memory functioning and impairment.

Adult↗
PubMed1986

Transcutaneous bilirubinometry in the newborn infant: state of the art.

Hyperbilirubinemia in the newborn infant continues to challenge physicians. Clinical evaluation and treatment have evolved well-established principles over the past decade. This review examines neonatal bilirubin metabolism and focuses on a recently developed clinical diagnostic tool, the transcutaneous bilirubinometer. In spite of some limitations, the transcutaneous bilirubinometer can be best applied as a screening tool to identify healthy full-term infants who require serum bilirubin determination. With proper application, this device can eliminate most invasive diagnostic testing. Optimal use of the instrument requires the relationship between the serum bilirubin concentration and the transcutaneous bilirubinometer index to be determined for each device, institution, and population.

Bilirubin↗
PubMed2004

[Current developments in cochlear implantation].

Over the last 20 years, cochlear implantation has become a well accepted treatment in patients suffering from hearing loss or congenital deafness. Results have been impressive,and indications for a cochlear implant have been extended continuously. Thanks to a sophisticated diagnostic procedure, optimization of the surgical technique, and the progression of interdisciplinary cooperation in the field of rehabilitation, the acceptance of cochlear implantation is growing significantly. The manufacturers of the devices are making great efforts to miniaturize the external components of the system, and new developments in electrode arrays, combined with new speech coding strategies, result in better speech understanding. The new developments in electrode design, however, are not necessarily improvements over recent years. Nevertheless, a very well functioning network of physicians, scientists, and manufacturers has acted and reacted in an outstanding manner to identify possible causes of post-implantation meningitis, have taken immediate counter measures and presented possibilities of prevention.

Cochlear Implantation↗
PubMed2006

The role of different imaging modalities: is MRI a conditio sine qua non for ETV?

OBJECTIVE: To describe the different imaging modalities used for the diagnosis and classification of hydrocephalus, their role in defining the optimal treatment of hydrocephalus and to define the optimal preoperative diagnostics for endoscopic third ventriculocisternostomy (ETV). METHODS: An overview on available imaging modalities for hydrocephalus will be given and their pros and cons discussed. In addition, different aspects of the treatment of hydrocephalus by shunts and by ETV will be highlighted. DISCUSSION: The role of the technical aspects of performing an ETV, the role of the surgeon's philosophy, the role of the urgency of the procedure, and the role of informed consent on the requirements for the imaging of the hydrocephalus will be discussed. CONCLUSION: The authors conclude that MRI is a conditio sine qua non for ETV in elective surgical cases.

Child↗