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PubMed2006

Use of a thin-section archive and enterprise 3D software for long-term storage of thin-slice CT data sets.

Rapid advances are changing the technology and applications of multidetector computed tomography (CT) scanners. The major increase in data associated with this new technology, however, breaks most commercial picture archiving and communication system (PACS) architectures by preventing them from delivering data in real time to radiologists and outside clinicians. We proposed a phased model for 3D workflow, installed a thin-slice archive and measured thin-slice data storage over a period of 5 months. A mean of 1,869 CT studies were stored per month, with an average of 643 images per study and a mean total volume of 588 GB/month. We also surveyed 48 radiologists to determine diagnostic use, impressions of thin-slice value, and requirements for retention times. The majority of radiologists thought thin slice was helpful for diagnosis and regularly used the application. Permanent storage of thin slice CT is likely to become best practice and a mission-critical pursuit for the health care enterprise.

Humans↗
PubMed1998

Data mining by clinicians.

Clinical databases are becoming commonplace in healthcare environments. However, clinicians have been unable to readily explore these information sources, because currently available data retrieval tools require substantial technical skill, as well as knowledge of the underlying database structures. To address this, we have defined a group of "atomic" queries, including both population-based and temporal predicates, to enable the extraction of clinically meaningful information form these databases. DXtractor is an application that incorporates this functionality, and allows clinicians to simply combine these atomic queries. In doing so, arbitrarily complex data retrieval and exploration becomes possible for the non-programming clinician.

Databases as Topic↗
PubMed1997

Restructuring routinely collected patient data: ORCA applied to andrology.

Hospital information systems do not always cover all required detail per specialty. This may lead to scattering of data over disparate systems and the paper record. The ORCA (Open Record for CAre) CPR offers a generic structure for record sharing, and record keeping tailored to specific needs. We studied whether a semantic integration of existing and new data was possible, using the ORCA structure. Existing andrology data, originating from separate sources, were utilized for this purpose. During normalization, validation and explication steps, latent problems in the source data were exposed and removed, followed by a merge with new data items. By conversion of source data to ORCA, a unique representation of medical concepts in the database was attained, facilitating retrieval of univocal data for multiple purposes. We conclude that the expansion to the andrology domain, including transparent integration of existing data, provides support for the generality of ORCA.

Ambulatory Care Information Systems↗
PubMed1976

New concepts in the design of a clinical laboratory information system (LIS).

Laboratory computers have expanded in potential and are now capable of handling a communication system to support patient care. New technics and interactive software to expand this function are described and were developed because of serious deficiencies discovered in the hospital laboratory operation. New concepts in ordering of tests, collection and identification of samples, reporting of results, and retrieval of data are described.

Clinical Laboratory Information Systems↗
PubMed1986

Systematic approach to diagnosis and coding of pediatric cardiac disease.

A new system for coding congenital heart defects and related problems was developed to facilitate the computerized storage and retrieval of detailed diagnostic information. The system is based on the segmental approach to diagnosis with comprehensive tables indicating all possible mutually exclusive intersegmental alignments and connections. Diagnostic entities rather than nomenclature are the subjects of the codes. This system represents the best effort to date to develop an all-inclusive, precise, and accurate code while insuring completeness and maximizing efficiency in data collection by the use of a highly structured code book.

Angiocardiography↗
PubMed2006

Parallel factor analysis combined with PLS regression applied to the on-line monitoring of Pichia pastoris cultures.

Various key variables (biomass, substrate and product) of bioprocesses should be monitored in order to retrieve useful information on the system, with the biomass (the cell density) the principal target. Although several analytical methods have been adapted and used to monitor the evolution of cell density evolution in cultures, a general method for performing this determination has not yet been established, as each technique has its own advantages and drawbacks. In the present work, noninduced glycerol batch cultures (for which biomass and substrate are the key variables) were monitored using multiwavelength fluorescence spectroscopy. The data gathered were modelled via PARAFAC-PLS chemometric methodologies, resulting in important qualitative and quantitative information about the behaviours of different biogenic fluorophors in batch cultures of the yeast Pichia pastoris. This information was used to predict the target process variables in such cultures; this permitted the applicability of this combined technique to bioprocess monitoring to be assessed.

Biomass↗
PubMed2003

Polymorphic drug metabolism (CYP2D6) and utilisation of psychotropic drugs in hospitalised psychiatric patients: a retrospective study.

AIM: The aim of the current retrospective study was to assess the influence of polymorphic drug metabolism as assessed by genotyping, on the on the utilisation of psychotropic drugs in hospitalised psychiatric patients. The utilisation of psychotropic drugs was assessed using pharmacy records with emphasis on the number of prescriptions and prescriptions for possible side effects. METHODS: CYP2D6 genotype was assessed in 241 psychiatric patients by investigation for the five most common allelic variants ( CYP2D6*3, *4, *6, *7, *8) and the presence of gene duplication using allele-specific polymerase chain reaction. Data concerning the pharmacotherapy of the patients were retrieved from the pharmacy information system. Data was analysed on differences observed in pharmacy records concerning the different metabolic classes: ultra rapid metabolisers (UMs), extensive metabolisers (EMs) and poor metabolisers (PMs). RESULTS: For CYP2D6, 2.5% was UM (95% CI: 0.5-4.5%, n=6) and 8.3% was PM (95% CI: 4.8-11.8%, n=20). Drugs metabolised by CYP2D6 were less frequently prescribed in PMs than EMs (21.1% vs 33.6%, P=0.023). The average duration of prescriptions was significantly lower in PMs than EMs (54 days vs 106 days, P=0.010). Between UMs and EMs, no significant differences were found, although a similar tendency was observed. With regard to dose, no consistent differences were observed between the CYP2D6 genotype classes. Drugs against Parkinsonian-like side effects were given twice as frequently in PMs as EMs (6.9% vs 3.4%, P=0.045). CONCLUSIONS: Patients with impaired CYP2D6 metabolism received fewer CYP2D6 drugs. PMs were more prone to Parkinsonian-like side effects as evidenced by more prescriptions for drugs combating these side effects. Dose titrations were not often used to compensate for genetic polymorphisms. Pharmacy records might be a useful tool to detect differences related to polymorphic metabolism.

Adult↗
PubMed2005

An innovative rapid response radiotherapy program to reduce waiting time for palliative radiotherapy.

BACKGROUND: Waiting for radiation therapy (RT) in Ontario has been a major problem for the past decade. In 1996, the Toronto-Sunnybrook Regional Cancer Centre (TSRCC) initiated a Rapid Response Radiotherapy Program (RRRP) to provide timely palliative RT for symptom relief of patients with terminal cancer. PURPOSE: This study reviews the clinical activity of the RRRP over the past 8 years to evaluate if we are meeting the objectives of the program. MATERIALS AND METHODS: From the TSRCC oncology patient information system (OPIS) database, we retrieved the number of patients referred to the RRRP, their demographics, diagnosis and treatment for the calendar years 1996 to 2003 inclusive. We calculated the time interval between referral to consultation, consultation to simulation and the percentage of cases who started RT on their initial consultation for all new cases referred to the RRRP. RESULTS: From 1996 to 2003, the number of cases seen in consultation increased from just over 200 cases annually in the first 2 years to about 500 cases per year in the last 4 years, for a total of 3,290. There were 1,792 (54%) men and 1,498 (46%) women; median age was 69 years (range, 21-95 years). Breast, lung, genitourinary and gastrointestinal primaries accounted for over 80% of all referrals. The majority was referred for palliative treatment of symptomatic bone (70%) or brain (14%) metastases. The dose fractionation for bone metastases was a single 8-Gy fraction in 45%, 20 Gy in five fractions in 42%, 30 Gy in ten fractions in 4% and other dose fractionations in 9%. Nearly 90% were seen within 2 weeks of referral (38% within 1 week). Eighty-five percent were simulated on the day of their initial consultation. Sixty percent started their RT treatment on the day of their consultation visit. The overall median interval from referral to treatment was 8 days. CONCLUSION: Over the past 8 years, the annual number of new cases referred to the RRRP has doubled. The overall median interval from referral to consultation was 8 days. Sixty percent were simulated, planned and started treatment on the day of their initial consultation. We therefore are meeting our goal of providing rapid access to palliative RT for symptomatic cancer patients.

Adult↗
PubMed1994

A software engineering approach for medical workstations development.

Multimedia medical workstations represent the natural tool for accessing the hospital information system environment. They are complex medical systems that have to gather, in a single framework, a large collection of components dealing with multimedia medical objects. To remain current with both medical practice and with advances in the computer science field, they have to allow the iterative addition of new functions to the set of existing ones. In this paper, after a survey of commonly required medical workstation functional components, we shall try to discuss how a software engineering approach can streamline the development of a medical workstation. Different software engineering tools needed to build the functional components of a workstation are described. Their integration in a single dedicated environment is considered through four perspectives: data, presentation, communication and control. Benefits and limitations of an object-oriented approach are discussed.

Computer Communication Networks↗
PubMed1991

A lung function information system.

A lung function information system (LFIS) was developed for the data analysis of pulmonary function tests at different locations. This system was connected to the hospital information system (HIS) for the retrieval of patient data and the storage of the lung function variables of patients to generate follow-up reports and to support financial and administrative management. The application programs were developed in such a way that high flexibility was obtained with respect to the patient-computer-technician interaction. The sampled data are stored on a disc to correct earlier decisions, perform recalculations and reanalyse the data for research purposes. When the measurements performed on a patient are authorized, the sampled data are deleted, except for when they are needed for future research. A distributed computer system was chosen to combine the benefits of a centralized system with those of several stand-alone systems. The main tasks of the central unit are to store collected data and computer programs, generate a final lung function report on laser printer and provide a connection to the HIS. In the satellite computers, which are located close to the lung function equipment, the signals and raw data are processed. Furthermore, the satellite computers were in use for program development and several research projects, and for the offline data processing of the lung function measurements from two other hospitals by means of a modem connection. The LFIS improved the quantity and quality of data acquisition. It resulted in an increased capacity of about 50% concerning spirometry, and facilitated time-consuming complex analyses. It also avoided miscalculations and mistakes in reports previously experienced with hand calculations.

Computer Systems↗
PubMed2005

DICOM router: an open source toolbox for communication and correction of DICOM objects.

RATIONALE AND OBJECTIVE: Today, the exchange of medical images and clinical information is well defined by the digital imaging and communications in medicine (DICOM) and Health Level Seven (ie, HL7) standards. The interoperability among information systems is specified by the integration profiles of IHE (Integrating the Healthcare Enterprise). However, older imaging modalities frequently do not correctly support these interfaces and integration profiles, and some use cases are not yet specified by IHE. Therefore, corrections of DICOM objects are necessary to establish conformity. The aim of this project was to develop a toolbox that can automatically perform these recurrent corrections of the DICOM objects. MATERIALS AND METHODS: The toolbox is composed of three main components: 1) a receiver to receive DICOM objects, 2) a processing pipeline to correct each object, and 3) one or more senders to forward each corrected object to predefined addressees. The toolbox is implemented under Java as an open source project. The processing pipeline is realized by means of plug ins. One of the plug ins can be programmed by the user via an external eXtensible Stylesheet Language (ie, XSL) file. Using this plug in, DICOM objects can also be converted into eXtensible Markup Language (ie, XML) documents or other data formats. DICOM storage services, DICOM CD-ROMs, and the local file system are defined as input and output channel. RESULTS: The toolbox is used clinically for different application areas. These are the automatic correction of DICOM objects from non-IHE-conforming modalities, the import of DICOM CD-ROMs into the picture archiving and communication system and the pseudo naming of DICOM images. CONCLUSION: The toolbox has been accepted by users in a clinical setting. Because of the open programming interfaces, the functionality can easily be adapted to future applications.

CD-ROM↗
PubMedDate not supplied

Class distributions on SOM surfaces for feature extraction and object retrieval.

A Self-Organizing Map (SOM) is typically trained in unsupervised mode, using a large batch of training data. If the data contain semantically related object groupings or classes, subsets of vectors belonging to such user-defined classes can be mapped on the SOM by finding the best matching unit for each vector in the set. The distribution of the data vectors over the map forms a two-dimensional discrete probability density. Even from the same data, qualitatively different distributions can be obtained by using different feature extraction techniques. We used such feature distributions for comparing different classes and different feature representations of the data in the context of our content-based image retrieval system PicSOM. The information-theoretic measures of entropy and mutual information are suggested to evaluate the compactness of a distribution and the independence of two distributions. Also, the effect of low-pass filtering the SOM surfaces prior to the calculation of the entropy is studied.

Artificial Intelligence↗
PubMedDate not supplied

Assessment of commercial compression algorithms, of the lossy DCT and lossless types, applied to diagnostic digital image files.

The need for diagnostic image compression of the lossy or irreversible type has been declining due to the rapid increase in commercially available formatted hard disk capacity. It is estimated that the latter has increased about three orders of magnitude in the past 14 years while the size of diagnostic image files has, of course, remained constant. During the same period, despite claims for significantly improved performance by vendors, it seems that only small progress has been made in commercial lossless and lossy compression algorithms. There is still no consensus for lossy compression to a level acceptable for diagnosis. This is mostly considered to be around a ratio of 10:1. However, acceptable compression ratios depend heavily on the type of images processed and may be compared with the 3:1 ratio produced by lossless algorithms. This last value was shown to increase to more than 5.5:1 for gamma-camera images when corrected for the noise content of individual bit planes and for the display capabilities of computer monitors. Therefore, any possible benefits of lossy over lossless compression become questionable when the currently available hard disk capacity and network transmission speed are considered against the inevitable loss of information in the lossy type of compression.

Algorithms↗
PubMed2003

Digital imaging.

Explore the source record for details and available documents.

Artificial Intelligence↗
PubMed2003

Routine determination of serum methylmalonic acid and plasma total homocysteine in Norway.

OBJECTIVE: To study the total number of combined analyses of methylmalonic acid (MMA) and total plasma homocysteine (tHcy) carried out during February 1998 at the Central Laboratory of Haukeland University Hospital. METHODS: Laboratory data and requester comments of 2917 subjects in whom MMA was requested during February 1998, were retrieved from the laboratory information system (LIS). In 2520 cases, the results from the combined analyses of MMA and tHcy were available. Requester comments were registered in the LIS in 1084 cases. Results from additional laboratory analyses were accessible in about 10%, of cases. RESULTS: General practitioners requested MMA and tHcy on three main indications, i.e. low cobalamin, "control" and neurological symptoms. Metabolites were requested in twice as many women than men. Furthermore, MMA was requested in younger age groups of women compared with men. Plasma tHcy and MMA showed positive correlations with age and serum creatinine, and tHcy was generally 1-2 micromol/L higher in men than in premenopausal women. In cobalamin- (serum cobalamin > 300 pmol/L) and/or folate- (serum folate > 10 nmol/L) replete subjects, the average difference in MMA or tHcy according to the highest and lowest creatinine quartiles was 0.08 and 5-6 micromol/L, respectively. Different combinations of MMA and tHcy were evaluated by using a 5 x 5 matrix of predefined concentration intervals. Based on this matrix, cobalamin and folate deficiency could be excluded or the likely diagnoses proposed in 76% of cases. Cobalamin deficiency or folate deficiency was likely in about 7% and 12% of the subjects investigated, respectively. CONCLUSIONS: A combined analysis of MMA and tHcy provides complementary diagnostic information. When interpreting MMA and tHcy values, age, gender and renal function in particular must be taken into account. Typical combinations of MMA and tHcy concentration intervals could be proposed, which could either exclude deficiency or indicate likely diagnoses and/or influence of confounders.

Adolescent↗
PubMed2004

Low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol and apolipoprotein B: relationships among the different measurements.

Serum low-density lipoprotein cholesterol (LDLC) value is a recognized target for atherosclerotic risk management, and is generally calculated using the "Friedewald formula". Alternative risk markers include directly measured LDLC, non-high-density lipoprotein cholesterol (non-HDLC) and apolipoprotein B (ApoB). The relationships among such various measured or calculated quantities in medium-sized sets of patient results were investigated. Results from two sets of patients were retrieved from our laboratory information systems. One group (n=8436) included results of cholesterol, HDLC, triglyceride (TG) and glucose measurements. A second group (n = 902) included, in addition, results of ApoB measurement. The results confirmed the unreliability of the Friedewald formula at TG >350 mg/dL (3.96 mmol/L), but also indicated TG-linked underestimation of LDLC below such a TG level. By contrast, non-HDLC values were shown to be independent of TG, and better correlated to ApoB than LDLC values. Mathematically, the difference between non-HDLC and LDLC is TG x 0.458 (values in mmol/L): therefore, the latter cannot be compared to (or converted into) the former by simply adding a constant amount. The ratio LDLC/ApoB was shown continuously to decrease with increasing TG concentrations, while the ratio non-HDLC/ApoB did not. The TG-dependent underestimation of LDLC may be the reason for the reported better cardiovascular risk predictivity of non-HDLC in diseases associated with TG increase, such as in diabetes. Non-HDLC values are not influenced by TG levels, and are better correlated with ApoB.

Apolipoproteins B↗
PubMed2001

Radiological image data migration. Practical experience and comparison of the costs of work.

PURPOSE: To identify costs deriving from data migration of obsolete digital archives by measuring the workload, and to analyse migration-associated problems. MATERIAL AND METHODS: Two digital archives were used (DTL and MOD) and the capacity of these archives could no longer support the needs of the Medical Imaging Centre. The entire content of the DLT archive and selected data from the MOD archive were transferred to the current higher capacity (17 TB) tape archive. The running time of work processes was measured by self-reporting, and the cost of work was calculated. RESULTS: The transfer of 43,096 studies required 314 working hours over the course of 15 months in total. The work was partly manual, partly automatic. The percentage of non-retrievable MOD images was 35. Less than 0.2% of the DLT image transfers failed due to incorrect patient or image data. The MOD - DLT transfer cost was six times higher per study than the DLT - DLT transmission cost. CONCLUSION: At present, data migration may be inevitable as the amount of data increases and technology advances. The data transfer proved to be labour intensive, with high fault sensitivity regarding the MOD archive. The cost of work of data migration was 0.4% of estimated digital archiving total yearly cost. Automated data migration is preferable.

Costs and Cost Analysis↗
PubMed2004

Verbal fluency patterns in two subgroups of patients with Alzheimer's disease.

Previous research has identified two subgroups of patients with Alzheimer's disease (AD) based on performance discrepancies on semantic and visual-constructional measures: Left AD (LAD) and Right AD (RAD). In this study, verbal fluency performances (Animal Fluency [AF] and Letter Fluency [FAS]) of these two subgroups were examined. It was hypothesized that LAD patients would perform worse on AF compared to FAS, due to an underlying breakdown of left-hemisphere semantic networks. On the other hand, the RAD group, which theoretically has a relatively preserved semantic system, yet difficulties retrieving overlearned information, was not expected to differ on the two fluency tasks. These predictions were based on the notion that the AF task requires intact retrieval and semantic processes, whereas the FAS task is reliant on retrieval processes alone. Patients were classified into subgroups on the basis of performance discrepancies on the Boston Naming Test (BNT) and Copy tasks: LAD (BNT < Copy); RAD (BNT > Copy). A split-plot ANOVA using demographically corrected standard T-scores revealed a significant main effect for fluency task, and a significant subgroup x fluency task interaction. LAD patients performed poorer on AF compared to FAS; there was no fluency task difference for the RAD group. Analysis of within-subcategory response clustering on AF revealed more instances of serial subclass exemplar responses by RAD members. These results support the loss theory in explaining the semantic deficit of LAD, and suggest that retrieval difficulties underlie the fluency problems of RAD.

Aged↗