Diagnostic accuracy

A clear understanding of the mechanical movement of machines and their components is an essential part of vibration analysis. This understanding, coupled with the forces applied by the process, are the foundation for diagnostic accuracy. 

For example, mechanical imbalance generates radial forces in all directions, but misalignment generally results in a radial force in a single direction that corresponds with the misaligned direction. The ability to determine the actual displacement direction of the machine s shaft and other components greatly improves diagnostic accuracy. 

This limitation prohibits the use of most microprocessor-based vibration analyzers for complex machinery or machines with variable speeds. Single-channel data-acquisition technology assumes the vibration profile generated by a machine-train remains constant throughout the data-acquisition process. This is generally true in applications where machine speed remains relatively constant (i.e., within 5 to fO rpm). In this case, its use does not severely limit diagnostic accuracy and can be effectively used in a predictive-maintenance program. 

The correlation between altered enzyme activities and a given disease, i.e., the diagnostic accuracy should be based on accepted symptoms and laboratory changes. Tissue diagnoses should be used whenever possible as a standard of reference (22). 

The diagnostic usefulness should be established by appropriate retrospective or prospective studies to see if the test in fact improves the diagnostic accuracy. For inherited enzyme diseases, the measurement of the enzyme activity can be diagnostically specific and highly useful. For otherwise obvious diseases such as metastatic prostatic carcinoma, enzyme tests may be of little value (24). 

Amador, E., Franey, R. J. and Massod, M. F. Serum glutamic-oxaloacetic transaminase activity Diagnostic accuracy of the revised spectrophotometric and the dinitrophenylhydrazine methods. Clin. Chem. (1966),... 

Early diagnosis of skin cancer is the key to improved prognosis. Diagnostic accuracy and clinical skills are two essential factors in the appropriate management of skin cancer. On presentation to a clinician s office, patients may offer a history of a new growth or an area of irritation. Conversely, the skin cancer may have been present for years undetected by the patient. The definitive diagnosis of any suspected cutaneous malignancy should be confirmed by a biopsy prior to treatment. 

Error caused by recombination is not a factor, so diagnostic accuracy is potentially higher than in indirect diagnosis. 

Cornel JH, Bax JJ, Elhendy A, Maat AP, Kimman GJ, Geleijnse ML et al. Biphasic response to dobutamine predicts improvement of global left ventricular function after surgical revascularization in patients with stable coronary artery disease imphcations of time course of recovery on diagnostic accuracy. J Am Coll Cardiol 1998 31 1002-1010... 

N.J. Dougall, S. Bmggink, K.P. Ebmeier, Systematic review of the diagnostic accuracy of 99mTc-HMPAO SPECT in dementia. Am. J. Geriatr. Psychiatry 12 (2004) 554-570. 

Initial staging. The first study comparing the diagnostic accuracy of integrated [ F]-FDG-PET/CT with CT alone, [ F]-FDG-PET alone and conventional visual correlation of [ F]-FDG-PET and CT in patients with NSCLC was published by Lardinois et al. [43]. Integrated [ F]-FDG-PET/CT provided additional information beyond that provided by visually correlated [ F]-FDG-PET and CT in 41% of the included patients. p F]-FDG-PET/CT also revealed to be significantly... 

In a meta-analysis, Westreenen et at. analyzed 12 studies concerning the diagnostic accuracy of [ F]-FDG-PET in staging the locoregional lymph node status [75]. The pooled sensitivity and specificity of [ F]-FDG-PET in detecting locoregional lymph node involvement were 51% and 84%, respectively. 

W. Chen, D.H. Silverman, S. Delaloye, J. Czernin, N. Kamdar, W. Pope, N. Satyamurthy, C. Schiepers, T. Cloughesy, F-FDOPA PET imaging of brain tumors Comparison study with F-FDG PET and evaluation of diagnostic accuracy, J. Nucl. Med. 47(6) (2006) 904-911. 

Available evidence indicates that mild dementia is rarely diagnosed, and even moderately severe dementia is under-recognized in clinical practice [51]. Thus, diagnostic accuracy is much lower at the earlier clinical, and especially presymptomatic, stages of the disease. 

Cohen LS, Escobar PF, Scharm C, Glimco B, Fishman DA. Three-dimensional power Doppler ultrasound improves the diagnostic accuracy for ovarian cancer prediction. Gynecol Oncol 2001 82(l) 40-48. 

Marker Cutoff Sensitivity (%) Specificity (%) PPV NPV Diagnostic Accuracy Ref. 

Lately a novel technique with milk in a commercially available test kit has been introduced in France (Diallartest). A positive APT has a high diagnostic accuracy for predicting the outcome of DBPCFC (Turnjamaa et al., 2006). 

Cosottini M, Calabrese R, Puglioli M et al. (2003) Contrast-enhanced three-dimensional MR angiography of neck vessels does dephasing effect alter diagnostic accuracy Eur Radiol 13 571-581... 

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