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PubMed2006

The relationship between nasopharyngeal carcinoma tumor volume and TNM T-classification: a quantitative analysis.

Recent findings show that tumor volume is a significant prognostic factor for the treatment of nasopharyngeal carcinoma (NPC). The inclusion of tumor volume as an additional prognostic factor in the UICC TNM classification system was suggested; however, how tumor volume could possibly be incorporated is still unexplored. In this paper, we report a quantitative analysis on the relationship between NPC tumor volume and T-classification, using the data from 206 NPC patients. By T-classification and semi-automatic tumor volume measurement, the difference in tumor volumes among the various TNM T-classification groups was examined. In addition, a statistics-based analysis scheme, which used the T-classification as the "gold standard", was proposed to classify NPC tumors into volume-based groups to explore the possible links. The results show that NPC tumor volume has positive correlation with advancing T-classification groups and significant difference existed in the distribution of T-classification among various volume-based groups (P < 0.001). By the proposed statistical scheme, tumor volume could be included as an additional prognostic factor in the TNM framework, following validation studies.

Adolescent↗

PubMed2002

How do gastric carcinoma classification systems relate to mucin expression patterns? An immunohistochemical analysis in a series of advanced gastric carcinomas.

Gastric carcinoma classifications differ in their value for distinguishing tumors according to their morphological pattern, functional properties, and biological significance. In this study we evaluated which of three established classification systems is best correlated with the expression patterns of certain mucins. A total of 160 gastric carcinomas from Turkey and Germany were screened immunohistochemically for the expression of MUC1, MUC2, MUC5AC, and MUC6, and the results were related to the different tumor categories in Lauren's, Carneiro's, and Goseki's classifications. It was found that in all three classifications carcinomas belonging to the gland-forming category most commonly expressed MUC1: 78% of Goseki's grade I carcinomas, 81.1% of Lauren's intestinal type carcinomas, and 82.8% of Carneiro's glandular type. MUC2 was expressed in all Goseki grade II carcinomas, which comprise the mucinous type, while it was not significantly associated with any of the other classifications. MUC5AC was found in all Goseki grade IV carcinomas, i.e., signet ring cell carcinomas. It was also significantly associated with Carneiro's mixed type and isolated cell type carcinomas, while there was no correlation with any of Lauren's types. MUC6 failed to show a relationship with any of the categories of the various classifications. We conclude that Goseki's classification is best correlated with MUC expression patterns because it distinguishes clearly between MUC1-positive gland-forming carcinomas, MUC2-positive mucinous ones, and MUC5AC-positive signet ring cell carcinomas. It is likely that each of these gastric carcinoma types has its own carcinogenesis.

Carcinoma↗

PubMed2002

The new Vienna classification of epithelial neoplasia of the gastrointestinal tract: advantages and disadvantages.

A number of seminars have shown considerable differences between Japanese and Western pathologists in the diagnostic differentiation of reactive changes, dysplasia and well-differentiated adenocarcinoma in gastroenterological biopsy material. Lesions that most Western pathologists identify as "dysplasia" are often considered adenocarcinomas in Japan. A comparison of the biopsy-based diagnoses with those established in resected mucosa, however, reveals appreciable diagnostic inexperience on the part of Western pathologists, with significant discrepancies between their diagnoses based on biopsies and those based on resected material. Against this background, a new classification of epithelial neoplasia of the gastrointestinal tract was drafted on the occasion of the World Congress of Gastroenterology in Vienna in 1998. By collapsing the diagnoses "high-grade adenoma/dysplasia, noninvasive carcinoma (carcinoma in situ), and suspected invasive carcinoma" into a single category ("noninvasive high-grade neoplasia", category 4), this scheme should largely eliminate the diagnostic discrepancies between Western and Japanese pathologists. As with every classification, the Vienna classification has its advantages and disadvantages; these are discussed here. The most important advantage of the Vienna classification is that the various categories are associated with different recommendations for further diagnostic and therapeutic measures. This applies in particular to category 4, with the recommendation for only local treatment initially (endoscopic mucosal resection or surgical excision). Since the introduction of the Vienna classification, the new World Health Organization classification of neoplasia of the gastrointestinal tract has recently been published, in which the term dysplasia has been replaced by "intraepithelial neoplasia". This means that the Vienna classification needs to be modified accordingly.

Adenocarcinoma↗

PubMed2003

Reproducibility of the 1998 World Health Organization/International Society of Urologic Pathology classification of papillary urothelial neoplasms of the urinary bladder.

OBJECTIVES: This study assessed the diagnostic agreement and intra- and inter-observer reproducibility of the World Health Organization/International Society of Urologic Pathology Consensus Classification of Urothelial Neoplasms (1998 WHO/ISUP classification) and the 1973 WHO classification. METHODS: A teaching set with 5 slides of each papillary neoplasm of low malignant potential, low-grade papillary carcinoma, high-grade papillary carcinoma, and a guideline, as well as a study set of 30 slides containing ten cases of each category, were sent to participants. Six pathologists expert in urological pathology reviewed the 30 slides of non-invasive papillary urothelial tumors in the study set. Diagnostic accuracy and reproducibility were evaluated using intra- and inter-rater techniques (kappa statistic). RESULTS: A moderate to substantial intra- and inter-observer reproducibility was achieved for both the 1998 WHO/ISUP and 1973 WHO classification. The results of the two classification systems were not different statistically ( P>0.05). Reproducibility was lower in low-grade tumors for both classifications. CONCLUSIONS: The new proposed classification system for non-invasive urothelial neoplasms does not increase the reproducibility. There is still a need for uniformity in grading in order to compare the different studies and therapies and to provide more accurate information for management.

Carcinoma, Papillary↗

PubMed1987

Classification of supraventricular tachycardias.

An ideal approach to classification of supraventricular arrhythmias would be based on exact knowledge of the pathophysiology and mechanism of the arrhythmia. Unfortunately, the mechanism may not be apparent from electrocardiographic data or indeed may not be known after extensive invasive and non-invasive studies. Difficulties are encountered in applying and extrapolating to patients criteria that are known to exist in experimental preparations. The traditional methods of classification have used electrocardiographic features and atrial rate. Although such classifications are simple, the criteria are arbitrary and electrocardiographically similar arrhythmias may have different mechanisms. A realistic classification must incorporate both electrocardiographic description and mechanism. The classification should be such that it can readily incorporate new knowledge in an additive way without completely restructuring the classification. A classification fulfilling these requirements would begin with electrocardiographic descriptors and end with mechanism, known or unknown. For example, a tachycardia may be characterized as supraventricular, atrial rate 300, 1:1 atrioventricular relation, with atrioventricular nodal reentry mechanism. It could then be qualified by further clinical descriptors such as incessant, paroxysmal or repetitive. With this approach, the initial descriptive category will always be constant and the mechanism known or unknown. As more data are obtained in future years, the "mechanism" segment of the descriptor may be added or revised.

Atrial Fibrillation↗

PubMed1992

A classification of acidified catchments in Britain.

To compare catchments of possible acidified waters in Britain an extensive database was compiled for nearly 600 catchments of lakes and streams for which chemical data were available. Information on the database included map-derived data, pollutant deposition estimates and hydrological characteristics. To stratify the catchment database a randomly selected subset of 328 catchments was used to derive eight classes of catchments using the classification program TWINSPAN. Several classifications were generated by this method using an increasing number of catchment parameters. TWINSPAN classes were defined on the basis of some catchment parameters (indicators) but were shown to be associated with other variables. A general linear model (GLM) analysis of the available chemical data was used to test the different classifications. A TWINSPAN classification which excluded soil and geology characteristics gave the best GLM model because soil and geology types were poorly correlated with other catchment parameters. However, because of the recognized importance of soils and geology in acidification processes, these parameters were introduced into the GLM model as separate GLM classes. The resulting three-class model (TWINSPAN class, soil type, geology type) proved superior to both the one-class model and to two-class models which included either soil or geology. It was demonstrated that the TWINSPAN classes were associated with particular geographical areas and particular monitoring programmes. The TWINSPAN classification was used to evaluate a set of catchments selected as long-term monitoring sites for Britain. In general, the set covered a wide range of catchment types as defined by the classification. It was possible to identify minor shortfalls in classes of catchment selected and suggest possible additions to the sampling programme. Whilst the classification procedure has been applied to possible acidified waters, the method is of general relevance to all catchments and waters of more diverse nature.

Journal Article↗

PubMed1978

Protist classification and the kingdoms of organisms.

Traditional classification imposed a division into plant-like and animal-like forms on the unicellular eukaryotes, or protists; in a current view the protists are a diverse assemblage of plant-, animal- and fungus-like groups. Classification of these into phyla is difficult because of their relatively simple structure and limited geological record, but study of ultrastructure and other characteristics is providing new insight on protist classification. Possible classifications are discussed, and a summary classification of the living world into kingdoms (Monera, Protista, Fungi, Animalia, Plantae) and phyla is suggested. This classification also suggests groupings of phyla into superphyla and form-superphyla, and a broadened kingdom Protista (including green algae, oomycotes and slime molds but excluding red and brown algae). The classification thus seeks to offer a compromise between the protist and protoctist kingdoms of Whittaker and Margulis and to combine a full listing of phyla with grouping of these for synoptic treatment.

Animals↗

PubMed1991

Validation of the TNM classification (4th edn) for lung cancer: first results of a prospective study of 1086 patients with surgical treatment.

For the purpose of testing the validity of the new TNM classification (fourth edition) for lung cancer, data from 1086 patients with surgical treatment were analysed prospectively. Several items were examined: (1) the agreement between clinical (TNM) and pathologically confirmed classification (pTNM); (2) the value of the various diagnostic tests in estimating the pathologically confirmed classification; (3) the influence of the TNM definitions on separating distinct prognostic groups. With regard to the primary tumour (T), clinical and pathological classification were identical in 64% of the cases. With regard to lymph node involvement (N), the agreement was 48%, for distant metastasis 90% and for the staging 55%. As for the primary tumour (T), the accuracy of radiography (59%) was nearly identical with that of computed tomography (58%). Both these diagnostic techniques were less precise in determining the extent of lymph node involvement (computed tomography 50% correct assessments, radiography 43%). The statistically significant differences in the prognoses for the various pT, pN and pM categories as well as for the pathological stages and the categories of the new R classification could be confirmed. The new 1987 TNM definitions for lung cancer make possible international conformity; the classification is also practically useful and the prognostic relevance improved. The new classifications thus provide a more reliable basis for establishing guidelines for individual oncological therapy strategies and for the exchange of information between different centres on the progress made in diagnosis and therapy of lung cancer.

Carcinoma, Bronchogenic↗

PubMed2004

Comparison of treatment response classifications between unidimensional, bidimensional, and volumetric measurements of metastatic lung lesions on chest computed tomography.

RATIONALE AND OBJECTIVES: To study the agreement in treatment response classifications between unidimensional (1D), bidimensional (2D), and volumetric (3D) methods of measuring metastatic lung nodules on chest computed tomography (CT). MATERIALS AND METHODS: Chest CT scans of 15 patients undergoing treatment for metastatic colorectal, renal cell, or breast carcinoma to the lungs were analyzed. CT images were acquired with 3 mm collimation and contiguous reconstruction. Two or three lung lesions were selected for each patient. Lesions were analyzed at baseline and two follow-up intervals of 1-4 months. 1D and 2D measurements were made with electronic calipers, while nodule volume was measured using a semiautomated segmentation system. Following the World Health Organization and RECIST (Response Evaluation Criteria in Solid Tumors) criteria, patients were categorized into four treatment response classifications. Volumetric criteria were used to classify response based on 3D measurements. RESULTS: Thirty-two lesions from 15 patients were analyzed. Because each patient had a baseline and two follow-up scans, this yielded 30 response classifications for each measurement technique. The 1D, 2D, and 3D measurements were concordant in 21 of 30 classifications. The 1D and 3D measurements were concordant in 29 of 30 classifications, while the 2D and 3D measurements were concordant in 23 of 30 classifications. Level of agreement among the three methods was measured using a kappa statistic (K). For 1D compared with 3D, K = 0.739 +/- 0.345 (visits 1, 2) and 0.273 +/- 0.323 (visits 2, 3). For 2D compared with 3D, K = 0.655 +/- 0.325 (visits 1, 2) and 0.200 +/- 0.208 (visits 2, 3). Agreement among the methods for round and ovoid nodules was also fair to poor. CONCLUSION: The three methods of tumor measurement show fair to poor agreement in treatment response classification. These findings have negative implications for the accuracy in which patients are classified under the World Health Organization or RECIST criteria and managed under cancer treatment protocols.

Breast Neoplasms↗

PubMed2006

Computer-aided diagnosis scheme for identifying histological classification of clustered microcalcifications by use of follow-up magnification mammograms.

RATIONALE AND OBJECTIVES: Our purpose in this study was to investigate the usefulness of follow-up magnification mammograms (i.e., both current and previous magnification mammograms) in a computer-aided diagnosis (CAD) scheme for identifying the histological classification of clustered microcalcifications. MATERIALS AND METHODS: Our database consisted of current and previous magnification mammograms obtained from 93 patients before and after 3-month follow-up: 11 invasive carcinomas, 19 noninvasive carcinomas of the comedo type, 25 noninvasive carcinomas of the noncomedo type, 23 mastopathies, and 15 fibroadenomas. In our CAD scheme, we extracted five objective features of clustered microcalcifications from each of the current and previous magnification mammograms by taking into account image features that experienced radiologists commonly use to identify histological classifications. These features were then merged by a modified Bayes discriminant function for distinguishing among five histological classifications. For the input of the modified Bayes discriminant function, we used five objective features obtained from the previous magnification mammogram (previous features), five objective features obtained from the current magnification mammogram (current features), and the set of the five previous features and the five current features. RESULTS: The classification accuracies with the five current features were higher than those with the five previous features. These classification accuracies were improved substantially by using the set of the five previous features and the five current features. For the set of the five previous features and the five current features, the classification accuracies of our CAD scheme were 81.8% (9 of 11) for invasive carcinoma, 84.2% (16 of 19) for noninvasive carcinoma of the comedo type, 76.0% (19 of 25) for noninvasive carcinoma of the noncomedo type, 73.9% (17 of 23) for mastopathy, and 86.8% (13 of 15) for fibroadenoma. CONCLUSION: Our CAD scheme with use of follow-up magnification mammograms improved classification performance for mammographic clustered microcalcifications.

Algorithms↗

PubMed2006

Value of the American College of Cardiology/American Heart Association angiographic classification of coronary lesion morphology in patients with in-stent restenosis. Insights from the Restenosis Intra-stent Balloon angioplasty versus elective Stenting (RIBS) randomized trial.

BACKGROUND: The implications of the American College of Cardiology/American Heart Association (ACC/AHA) lesion classification in patients with in-stent restenosis (ISR) are unknown. METHODS: Four hundred fifty patients included in the RIBS randomized study were analyzed. A centralized core laboratory assessed ISR classifications including ACC/AHA, the classification of Mehran et al (Circulation 1999;100:1872-8), diffuse/focal, and a new quantitative ISR index (lesion length/stent length). Logistic regression models were constructed for prespecified outcome measures including (1) unsatisfactory acute results and (2) recurrent restenosis rate. RESULTS: Complex (B2/C) lesions (78%) more frequently obtained unsatisfactory acute results (20% vs 8%, P = .007), smaller minimal lumen diameter after the procedure (2.45 +/- 0.5 vs 2.73 +/- 0.5 mm, P = .001) and at follow-up (1.48 +/- 0.8 vs 1.94 +/- 0.8 mm, P = .0001), and had a higher restenosis rate (43 vs 24%, P = .001) than simple (A/B1) lesions. On logistic regression analysis, all classification schemes were useful to predict unsatisfactory initial results (area under the curve: 0.63, 0.61, 0.59, and 0.62) and recurrent restenosis (area under the curve: 0.60, 0.64, 0.61, and 0.63). The predictive ability of these schemes persisted despite adjustment for potential confounders. Although the ACC/AHA classification was a better predictor of acute results, the classification of Mehran was superior to predict restenosis. CONCLUSIONS: The ACC/AHA classification provides a useful tool to determine acute procedural results and the long-term angiographic outcome of patients with ISR.

Aged↗

PubMed2006

Classification of single MEG trials related to left and right index finger movements.

OBJECTIVE: Most non-invasive brain-computer interfaces (BCIs) classify EEG signals. Here, we measured brain activity with magnetoencephalography (MEG) with an aim to characterize and classify single MEG trials during finger movements. We also examined whether averaging consecutive trials, or averaging signals from neighboring sensors, would improve classification accuracy. METHODS: MEG was recorded in five subjects during lifting the left, right or both index fingers. Trials were classified using features, defined by an expert, from averaged spectra and time-frequency representations. RESULTS: Classification accuracy of left vs. right finger movements was 80-94%. In the three-category classification (left, right, both), accuracy was 57-67%. Averaging three consecutive trials improved classification significantly in three subjects. Instead, spatial averaging across neighboring sensors decreased accuracy. CONCLUSIONS: The use of averaged signals to find appropriate features for single-trial classification proved useful for the two-class classification. The classification accuracy was comparable to that in previous EEG studies. SIGNIFICANCE: MEG provides another useful method to measure brain signals to be used in BCIs. Good performance was obtained when the classified signals were generated by two distinct sources in the left and right hemisphere. The present findings should be extended to multi-task cases involving additional brain areas.

Adult↗

PubMed2005

Classification of EEG signals using neural network and logistic regression.

Epileptic seizures are manifestations of epilepsy. Careful analyses of the electroencephalograph (EEG) records can provide valuable insight and improved understanding of the mechanisms causing epileptic disorders. The detection of epileptiform discharges in the EEG is an important component in the diagnosis of epilepsy. As EEG signals are non-stationary, the conventional method of frequency analysis is not highly successful in diagnostic classification. This paper deals with a novel method of analysis of EEG signals using wavelet transform and classification using artificial neural network (ANN) and logistic regression (LR). Wavelet transform is particularly effective for representing various aspects of non-stationary signals such as trends, discontinuities and repeated patterns where other signal processing approaches fail or are not as effective. Through wavelet decomposition of the EEG records, transient features are accurately captured and localized in both time and frequency context. In epileptic seizure classification we used lifting-based discrete wavelet transform (LBDWT) as a preprocessing method to increase the computational speed. The proposed algorithm reduces the computational load of those algorithms that were based on classical wavelet transform (CWT). In this study, we introduce two fundamentally different approaches for designing classification models (classifiers) the traditional statistical method based on logistic regression and the emerging computationally powerful techniques based on ANN. Logistic regression as well as multilayer perceptron neural network (MLPNN) based classifiers were developed and compared in relation to their accuracy in classification of EEG signals. In these methods we used LBDWT coefficients of EEG signals as an input to classification system with two discrete outputs: epileptic seizure or non-epileptic seizure. By identifying features in the signal we want to provide an automatic system that will support a physician in the diagnosing process. By applying LBDWT in connection with MLPNN, we obtained novel and reliable classifier architecture. The comparisons between the developed classifiers were primarily based on analysis of the receiver operating characteristic (ROC) curves as well as a number of scalar performance measures pertaining to the classification. The MLPNN based classifier outperformed the LR based counterpart. Within the same group, the MLPNN based classifier was more accurate than the LR based classifier.

Adult↗

PubMed2006

ILAE classification of epilepsy syndromes.

The efforts of the International League against Epilepsy (ILAE) to devise classifications of the epilepsies has greatly improved communication among epileptologists and influenced both basic and clinical research. Several classifications have been proposed since 1970; the most recent classification of epilepsy syndromes and epilepsies was published in 1989. Since 1997, the ILAE Task Force on Classification and Terminology has been evaluating this classification and some modifications have been recommended. Although the 1989 classification can be criticized and needs to be updated, it has been widely accepted and is universally employed. Consequently, the Task Force has agreed not to propose a replacement until a clearly better classification can be created.

Epilepsy↗

PubMed2005

Developing a national integrated classification of health care interventions in Sweden.

BACKGROUND: Existing classifications in Sweden of health care interventions used for quality assurance issues and for decisions on resource allocation does not capture all types of health care interventions. The work of professional groups like nurses, physiotherapists, and occupational therapists is partly invisible. There is a need to develop a classification of health care interventions that comprise all activity within the health care sector. AIM: To describe a multi-professional collaborative work on classification development and to provide suggestions for an organizing structure that can capture interventions in the health care services incorporating different professional perspectives. RESULTS: The professional groups reached a common understanding about the use of the classification of The International Classification of Functioning, Disability and Health (ICF) as a unifying framework in the classification of health care interventions. Proposal was made for a revised structure of a current classification of interventions using ICD as unifying framework. CONCLUSION: The use of ICF as a unifying framework is seen as a fruitful way of overcoming professional differences, and by that supporting the process of reaching a common understanding and use of a common language when describing interventions in health care.

Delivery of Health Care, Integrated↗

PubMed2005

New classification of ophthalmic viscosurgical devices--2005.

PURPOSE: To revise the generally accepted classification of ophthalmic viscosurgical devices (OVDs) to include cohesion data and the new class of viscous dispersive OVDs. SETTING: York Finch Eye Associates, Toronto, Ontario, Canada, and Alcon Research Limited, Fort Worth, Texas, USA. METHODS: Pseudoplasticity and cohesion-dispersion (CDI) data of DisCoVisc (hyaluronic acid 1.6%-chondroitin sulfate 4%), a new viscous dispersive OVD, were determined and compared with existing OVDs. The existing classification of OVDs was unable to accommodate its properties, so the classification was modified to include a new class and other potential new classes which currently remain unoccupied. RESULTS: Current OVD classification, although based on the clinically significant rheologic parameters of zero-shear viscosity and cohesion, only uses zero-shear viscosity because of the high correlation of these 2 parameters in existing OVDs. The appearance of DisCoVisc forces modification of the existing scheme because it does not fit into a preexisting category. The new proposed broadened classification is changed from a 1-dimensional list into a 2-dimensional table and considers CDI independently from viscosity for all OVDs. Expansion of the classification of OVDs in this manner predicts further possible new innovative OVDs for surgical use. CONCLUSION: The surgical behavior of OVDs can be predicted by their position in a classification of OVDs based upon zero-shear viscosity and cohesion.

Adhesiveness↗

PubMed2006

A simple method for protein structural classification.

Since the concept of structural classes of proteins was proposed, the problem of protein classification has been tackled by many groups. Most of their classification criteria are based only on the helix/strand contents of proteins. In this paper, we proposed a method for protein structural classification based on their secondary structure sequences. It is a classification scheme that can confirm existing classifications. Here a mathematical model is constructed to describe protein secondary structure sequences, in which each protein secondary structure sequence corresponds to a transition probability matrix that characterizes and differentiates protein structure numerically. Its application to a set of real data has indicated that our method can classify protein structures correctly. The final classification result is shown schematically. So it is visual to observe the structural classifications, which is different from traditional methods.

Algorithms↗

PubMedDate not supplied

Submucous myomas: a new presurgical classification to evaluate the viability of hysteroscopic surgical treatment--preliminary report.

STUDY OBJECTIVE: To develop a new preoperative classification of submucous myomas for evaluating the viability and the degree of difficulty of hysteroscopic myomectomy. DESIGN: Retrospective study (Canadian Task Force classification II-3) SETTING: University teaching hospitals. PATIENTS: Fifty-five patients who underwent hysteroscopic resection of submucous myomas. INTERVENTION: The possibility of total resection of the myoma, the operating time, the fluid deficit, and the frequency of any complications were considered. The myomas were classified according to the Classification of the European Society for Gynaecological Endoscopy (ESGE) and by our group's new classification (NC), which considers not only the degree of penetration of the myoma into the myometrium, but also adds in such parameters as the distance of the base of the myoma from the uterine wall, the size of the nodule (cm), and the topography of the uterine cavity. The Fisher's exact test, the Student's t test, and the analysis of variance test were used in the statistical analysis. A p value less than .05 in the two-tailed test was considered significant. MEASUREMENTS AND MAIN RESULTS: In 57 myomas, hysteroscopic surgery was considered complete. There was no significant difference among the three ESGE levels (0, 1, and 2). Using the NC, the difference between the numbers of complete surgeries was significant (p <.001) for the two levels (groups I and II). The difference between the operating times was significant for the two classifications. With respect to the fluid deficit, only the NC showed significant differences between the levels (p = .02). CONCLUSIONS: We believe that the NC gives more clues as to the difficulties of a hysteroscopic myomectomy than the standard ESGE classification. It should be stressed that the number of hysteroscopic myomectomies used in this analysis was low, and it would be interesting to evaluate the performance of the classification in a larger number of patients.

Female↗