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  • 1
    In: Blood, American Society of Hematology, Vol. 134, No. Supplement_1 ( 2019-11-13), p. 2094-2094
    Abstract: Background: In multicolor flow cytometry (MFC), switching to a device that supports more fluorochromes per measurement is a common transition in a diagnostic laboratory. Usually this process involves a period of applying both protocols in parallel, the old one validating the new one. Mostly, only very few of the rare diagnoses will be assessed by both protocols. With respect to decision support systems that are based on artificial intelligence this is too little data to train a new classifier considering the need for high accuracy. New approaches of applying existing knowledge to new settings are therefore desirable. Methods: We obtained MFC data (fcs files) for the two separate sets of samples that were analyzed for the same markers but applying different fluorochrome conjugates and different combinations of antibodies as either 5-color or 9-color combinations both analyzed on the same cytometer. The former platform consisted of 6 combinations with the markers shown in Figure 1A. The latter platform consisted of 3 combinations with the markers shown in Figure 1B. Samples were assigned to one of the B-cell neoplasm classes CLL/MBL, mantle cell lymphoma (MCL), CLL/PL (PL), lymphoplasmacytic lymphoma (LPL), marginal zone lymphoma (MZL), follicular lymphoma (FL), hairy cell leukemia (HCL) or to normal. We have applied transfer learning (TL), which is a machine learning method to improve the learning of a new task through the transfer of knowledge from a related task that has already been learned. We first train a base network on a base dataset and task, and then we transfer the learned features to a second target network to be trained on a separate dataset. In the present study TL was applied to two different types of MFC protocols. We trained a multi-layer neural network for each of the MFC protocols, while the output layer of both networks remained the same, that is the assignment of unclassified MFC data to seven subtypes of B-cell neoplasms or to the class of absence of B-cell neoplasm. However, for the two different protocols we modified the lower layers of the network to fit the respective combinations of analyzed antigens. We initialized the weights of the upper 5 layers in the 5-color network consisting of a dense layer with 128 nodes, a batch normalization layer with 128 nodes, a second dense layer with 64 nodes, a batch normalization layer with 64 nodes and a final dense layer with 8 nodes with weights from the same layers in the 9-color network. The weight matrices for the dense layers are of the form (wi, bi) where the first component is the weights learnt and the second is the bias vector, each of these vectors of the shape (number of nodes in previous layer * number of nodes in the current layer). Results: We first assessed the performance of the classification processes for networks that were solely trained on the MFC data of one of the two sets. The distributions of classes for both sets were as shown in Figure 1C. For a random 50/50 split into training and test samples of this data we achieved an overall accuracy of 0.70 for the 5-color data, compared to a 0.82 accuracy for the 9-color data. When we adjusted for the same number of samples in each subtype, there were no significant differences between the two sets, proving the equivalence of both protocols. To assess the benefit of transfer learning, we initialized the upper layers of the 5-color model with the weights of the 9-color model, as more data was in total available from this data set. With knowledge transfer we already achieved an accuracy of 0.7 with 1000 training samples and an accuracy of 0.82 with 4000 training samples. Even more prominent was the improvement of the performance for the rare subtypes, FL, HCL, LPL, PL, MCL and MZL. With the training set consisting of 400 samples from the rare subtypes, the accuracy obtained for these classes was only 0.15; with transfer learning the accuracy for these rare subtypes increased by two thirds. The most prominent improvement of specificity was seen for the subtype FL from 0.35 to 0.57. Conclusion: We created a framework that enables knowledge transfer for the interpretation of MFC data in B-cell neoplasm diagnostics by an artificial neural network. Our approach is not only applicable for transitions to new protocols, it also allows pooling data of different sources. In so doing, the accuracy for the detection of rare B-cell neoplasm subtypes can be increased by joining forces in a collaborative effort by involving multiple different data sets. Disclosures Elsner: res mechanica: Employment, Equity Ownership. Lueling:res mechanica: Employment, Equity Ownership. Schabath:MLL Munich Leukemia Laboratory: Employment. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2019
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 2
    Online Resource
    Online Resource
    Public Library of Science (PLoS) ; 2011
    In:  PLoS Computational Biology Vol. 7, No. 3 ( 2011-3-17), p. e1002013-
    In: PLoS Computational Biology, Public Library of Science (PLoS), Vol. 7, No. 3 ( 2011-3-17), p. e1002013-
    Type of Medium: Online Resource
    ISSN: 1553-7358
    Language: English
    Publisher: Public Library of Science (PLoS)
    Publication Date: 2011
    detail.hit.zdb_id: 2193340-6
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  • 3
    In: Blood, American Society of Hematology, Vol. 134, No. Supplement_1 ( 2019-11-13), p. 886-886
    Abstract: Introduction: Flow cytometry is an integral part of routine diagnostics for hematologic malignancies and is most relevant in mature B-cell neoplasms (BCN). While quality management systems are widely applied for flow cytometric procedures of sample preparation and measurement, data analysis and interpretation still are completely relying on expert knowledge individually applied to each patient sample. To reduce the dependency on expert knowledge and to potentially increase consistency of data interpretation by lowering inter-observer variability the implementation of automated processes is desirable. Aim: To prospectively assess an artificial neural network applied to unselected samples analyzed by flow cytometry for suspected BCN. Patients and methods: Between April and July 2019 a total of 3272 unselected samples (peripheral blood n=2304, bone marrow aspirate n=968) of adult patients with suspected BCN were flow cytometrically analyzed applying two 9-color tubes of antibody cocktails targeting a total of 16 antigens (tube 1: FMC7, CD10, IgM, CD79b, CD20, CD23, CD19, CD5, CD45; tube 2: Kappa, Lambda, CD38, CD25, CD11c, CD103, CD19, CD22, CD45). An artificial neural network was used to predict previously learned classes of BCN based on unprocessed raw data as obtained from the cytometer. Same data was analyzed in parallel during routine workflow applying expert knowledge that also served as ground truth. Results: Routine diagnostic procedures resulted in the following diagnoses; CLL n=481 (14.7%), CLL/PL n=19 (0.6%), follicular lymphoma (FL) n=16 (0.5%), hairy cell leukemia (HCL) n=61 (1.9%), variant hairy cell leukemia (vHCL) n=3 (0.1%), lymphoplasmacytic lymphoma (LPL) n=46 (1.4%), mantle cell lymphoma (MCL) n=29 (0.9%), marginal zone lymphoma (MZL) n=11 (0.3%), monoclonal B-cell lymphocytosis, CLL type (MBL) n=229 (7.0%), no evidence of BCN n=2377 (72.6%). 117 cases had low level infiltration by BCN ( & lt;1%) and were not subject to evaluation by the algorithm. 778 cases had infiltration of at least 1% (median 39%, maximum 98%) and, together with negative cases, were subject to evaluation by the algorithm, i.e. 3155 cases in total. The artificial neural network returns probabilities of the classes listed above where the maximum probability refers to the most likely diagnosis. Maximum probabilities were high, i.e. at least 95%, in 2445/3155 cases (77.5%). Results of these 2445 cases with a high confidence level of the classifier were compared to results obtained by expert evaluation of the identical flow cytometric data. First, we focused on correct predictions of presence or absence of BCN. Prediction was correct in 2437/2445 cases (99.7%). 8 cases misclassified (3 BM, 5 PB) included 6 BCN (1 MCL, 1% infiltration; 1 HCL, 1%; 2 CLL, 1%/4%; 2 LPL, 2%/2%) classified as no evidence of lymphoma and 2 cases without BCN classified as MZL, respectively. Next, we analyzed the correct predictions of CD5 positive BCN vs. CD5 negative BCN vs. no BCN. Prediction was correct in 2435/2445 cases (99.6%). In addition to the wrongly predicted cases mentioned above, 2 cases (both PB) were correctly classified BCN but CD5 positivity was incorrectly predicted. Thus, 1 CLL and 1 CLL/PL (both & gt;10% infiltration) were misclassified as LPL. Finally, we analyzed correct predictions of each class. Prediction was correct in 2429/2445 cases (99.3%). Besides the above mentioned wrongly predicted cases another 6 cases (2 BM, 4 PB) were correctly classified BCN with correct prediction of CD5 positivity but incorrect class prediction: 3 MCL (2%/61%/64%) and 1 MBL (8%) were classified as CLL/PL. 1 HCL (24%) and 1 vHCL (17%) were classified as MZL. Conclusions: The prospective application of an artificial neural network to a large set of flow cytometric raw data results in correct predictions of both presence of BNC and class of BCN at high accuracy ( & gt;99%) without any overconfidence effects of the classifier. Misclassified cases were assigned to classes with phenotypes most similar to the correct classes. Further development will focus on identification of small BCN populations, increase of the portion of cases correctly predicted with high probability and generalization of the approach to different antibody cocktails and additional hematologic neoplasms in order to exploit the diagnostic potential of the algorithm. Disclosures Kern: MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Elsner:res mechanica: Employment, Equity Ownership. Schabath:MLL Munich Leukemia Laboratory: Employment. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Lueling:res mechanica: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2019
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 4
    In: Patterns, Elsevier BV, Vol. 2, No. 10 ( 2021-10), p. 100351-
    Type of Medium: Online Resource
    ISSN: 2666-3899
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2021
    detail.hit.zdb_id: 3019416-7
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  • 5
    In: HemaSphere, Ovid Technologies (Wolters Kluwer Health), Vol. 7, No. S3 ( 2023-08), p. e5706814-
    Type of Medium: Online Resource
    ISSN: 2572-9241
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2023
    detail.hit.zdb_id: 2922183-3
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  • 6
    In: Cytometry Part A, Wiley, Vol. 97, No. 10 ( 2020-10), p. 1073-1080
    Abstract: The wealth of information captured by multiparameter flow cytometry (MFC) can be analyzed by recent methods of computer vision when represented as a single image file. We therefore transformed MFC raw data into a multicolor 2D image by a self‐organizing map and classified this representation using a convolutional neural network. By this means, we built an artificial intelligence that is not only able to distinguish diseased from healthy samples, but it can also differentiate seven subtypes of mature B‐cell neoplasm. We trained our model with 18,274 cases including chronic lymphocytic leukemia and its precursor monoclonal B‐cell lymphocytosis, marginal zone lymphoma, mantle cell lymphoma, prolymphocytic leukemia, follicular lymphoma, hairy cell leukemia, lymphoplasmacytic lymphoma and achieved a weighted F1 score of 0.94 on a separate test set of 2,348 cases. Furthermore, we estimated the trustworthiness of a classification and could classify 70% of all cases with a confidence of 0.95 and higher. Our performance analyses indicate that particularly for rare subtypes further improvement can be expected when even more samples are available for training. © 2020 The Authors. Cytometry Part A published by Wiley Periodicals LLC. on behalf of International Society for Advancement of Cytometry.
    Type of Medium: Online Resource
    ISSN: 1552-4922 , 1552-4930
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2180639-1
    SSG: 12
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  • 7
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2010
    In:  The Journal of the Acoustical Society of America Vol. 128, No. 6 ( 2010-12-01), p. 3577-3584
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 128, No. 6 ( 2010-12-01), p. 3577-3584
    Abstract: Using conformal mapping, fluid motion inside the cochlear duct is derived from fluid motion in an infinite half plane. The cochlear duct is represented by a two-dimensional half-open box. Motion of the cochlear fluid creates a force acting on the cochlear partition, modeled by damped oscillators. The resulting equation is one-dimensional, more realistic, and can be handled more easily than existing ones derived by the method of images, making it useful for fast computations of physically plausible cochlear responses. Solving the equation of motion numerically, its ability to reproduce the essential features of cochlear partition motion is demonstrated. Because fluid coupling can be changed independently of any other physical parameter in this model, it allows the significance of hydrodynamic coupling of the cochlear partition to itself to be quantitatively studied. For the model parameters chosen, as hydrodynamic coupling is increased, the simple resonant frequency response becomes increasingly asymmetric. The stronger the hydrodynamic coupling is, the slower the velocity of the resulting traveling wave at the low frequency side is. The model’s simplicity and straightforward mathematics make it useful for evaluating more complicated models and for education in hydrodynamics and biophysics of hearing.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
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    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2010
    detail.hit.zdb_id: 1461063-2
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