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PubMed1997

How does computer-assisted digital wall motion analysis influence observer agreement and diagnostic accuracy during stress echocardiography?

This study assessed interobserver and intraobserver variation and diagnostic accuracy during 25 dipyridamole stress echocardiography tests interpreted with different analysis systems: a) computer display of high frame rate digital cineloops (47 frames/s); b) computer display of lower frame rate digital cineloops (24 frames/s); and c) videotape recordings. The majority of the patients (84%) had documented coronary artery disease with baseline wall motion abnormalities due to previous myocardial infarctions and/or coronary bypass surgery, thus comprising a population with difficult interpretation of stress echocardiography. Diagnostic accuracy was assessed using coronary angiography as reference method. Interobserver and intraobserver agreement was highest when analysis was performed from computer-displayed cineloops, 96 and 92%, respectively, compared to 84 and 80% respectively, using videotape recordings. Sensitivity for identification of coronary artery stenosis was similar using digital cineloops with high frame rate or videotape recordings (67% to 80% for both systems), and tended to be lower using cineloops with lower frame rate for analysis (53%). Inter- and intraobserver differences for wall motion score index were not significantly influenced by the analysis system. We conclude that computer assisted analysis with high frame rate of the displayed cineloops provides optimal observer agreement and diagnostic accuracy in the same range as videotape analysis in patients undergoing stress echocardiography.

Adult↗
PubMed2001

Malaria diagnosis and treatment under the strategy of the integrated management of childhood illness (IMCI): relevance of laboratory support from the rapid immunochromatographic tests of ICT Malaria P.f/P.v and OptiMal.

The algorithm developed for the integrated management of childhood illness (IMCI) provides guidelines for the treatment of paediatric malaria. In areas where malaria is endemic, for example, the IMCI strategy may indicate that children who present with fever, a recent history of fever and/or pallor should receive antimalarial chemotherapy. In many holo-endemic areas, it is unclear whether laboratory tests to confirm that such signs are the result of malaria would be very relevant or useful. Children from a holo-endemic region of Tanzania were therefore checked for malarial parasites by microscopy and by using two rapid immunochromatographic tests (RIT) for the diagnosis of malaria (ICT Malaria P.f/P.v and OptiMal. At the time they were tested, each of these children had been targeted for antimalarial treatment (following the IMCI strategy) because of fever and/or pallor. Only 70% of the 395 children classified to receive antimalarial drugs by the IMCI algorithm had malarial parasitaemias (68.4% had Plasmodium falciparum trophozoites, 1.3% only P. falciparum gametocytes, 0.3% P. ovale and 0.3% P. malariae). As indicators of P. falciparum trophozoites in the peripheral blood, fever had a sensitivity of 93.0% and a specificity of 15.5% whereas pallor had a sensitivity of 72.2% and a specificity of 50.8%. The RIT both had very high corresponding sensitivities (of 100.0% for the ICT and 94.0% for OptiMal) but the specificity of the ICT (74.0%) was significantly lower than that for OptiMal (100.0%). Fever and pallor were significantly associated with the P. falciparum asexual parasitaemias that equalled or exceeded the threshold intensity (2000/microl) that has the optimum sensitivity and specificity for the definition of a malarial episode. Diagnostic likelihood ratios (DLR) showed that a positive result in the OptiMal test (DLR = infinity) was a better indication of malaria than a positive result in the ICT (DLR = 3.85). In fact, OptiMal had diagnostic reliability (0.93) which approached that of an ideal test and, since it only detects live parasites, OptiMal is superior to the ICT in monitoring therapeutic responses. Although the RIT may seem attractive for use in primary health facilities because relatively inexperienced staff can perform them, the high cost of these tests is prohibitive. In holo-endemic areas, use of RIT or microscopical examination of bloodsmears may only be relevant when malaria needs to be excluded as a cause of illness (e.g. prior to treatment with toxic or expensive drugs, or during malaria epidemics). Wherever the effective drugs for the first-line treatment of malaria are cheap (e.g. chloroquine and Fansidar), treatment based on clinical diagnosis alone should prove cost-saving in health facilities without microscopy.

Algorithms↗
PubMed2006

A simple method to combine multiple molecular biomarkers for dichotomous diagnostic classification.

BACKGROUND: In spite of the recognized diagnostic potential of biomarkers, the quest for squelching noise and wringing in information from a given set of biomarkers continues. Here, we suggest a statistical algorithm that--assuming each molecular biomarker to be a diagnostic test--enriches the diagnostic performance of an optimized set of independent biomarkers employing established statistical techniques. We validated the proposed algorithm using several simulation datasets in addition to four publicly available real datasets that compared i) subjects having cancer with those without; ii) subjects with two different cancers; iii) subjects with two different types of one cancer; and iv) subjects with same cancer resulting in differential time to metastasis. RESULTS: Our algorithm comprises of three steps: estimating the area under the receiver operating characteristic curve for each biomarker, identifying a subset of biomarkers using linear regression and combining the chosen biomarkers using linear discriminant function analysis. Combining these established statistical methods that are available in most statistical packages, we observed that the diagnostic accuracy of our approach was 100%, 99.94%, 96.67% and 93.92% for the real datasets used in the study. These estimates were comparable to or better than the ones previously reported using alternative methods. In a synthetic dataset, we also observed that all the biomarkers chosen by our algorithm were indeed truly differentially expressed. CONCLUSION: The proposed algorithm can be used for accurate diagnosis in the setting of dichotomous classification of disease states.

Algorithms↗
PubMed2004

Progress of control and prevention programs for bovine viral diarrhea virus in Europe.

In Europe, nationwide BVD control programs based on the TC principle have been running for up to 10 years in the Nordic countries. The results have shown that BVD eradication by removal of PI animals without use of vaccines is effective and that today's diagnostic tests, when used by experienced diagnosticians, are suitable for this task. Furthermore, to avoid control programs becoming Sisyphean tasks, adherence to strict biosecurity guide-lines to minimize infection of susceptible herds is a crucial additional measure. Efficient organization of testing, with sufficient capacity of diagnostic laboratories, is also important to minimize the period of overlap when remaining infected and recently emerged naive herds coexist close to each other. Control programs based on voluntary participation are possible, but when approaching final clearance of a national herd, significant delays can easily be suffered if any herd owners are allowed not to clear their herds. The control schemes used in the Nordic countries were tailored to fit the structure of the cattle production in each country. If BVD control programs based on the same principles are to be set up for other bovine populations,it is important to recognize and take into account for differences in the epidemiology of BVD and in the structure of the animal production,including cattle density and husbandry practices. To ensure optimal performance of the diagnostic tests, the diversity of BVDV in the region to be tested should also be considered.

Animals↗
PubMed2004

Short communication: An assessment of the use of malaria rapid tests by village health volunteers in rural Laos.

Rapid malaria diagnosis, a key component of malaria control strategies, is hampered by the expense and training requirements of reliable microscopy. Rapid malaria antigen tests may improve the diagnosis of malaria in the rural tropics. After 1 h training 64 village health volunteers (VHVs) from rural Laos, with no previous laboratory experience, performed two malaria rapid diagnostic tests (ParacheckPf and OptiMAL) accurately. The reliability of six VHVs was assessed longitudinally, over 10 months with different frequencies of retraining. Compared with microscopy, error rates in dipstick interpretation were low (<2%) for both tests and were not associated with retraining frequency (P>0.2). Previously untrained Lao VHVs performed malaria rapid tests reliably with high sensitivity and specificity after minimal training.

Adult↗
PubMed2003

[Endoscopic ultrasonography of the upper digestive tract].

Endoscopic Ultrasonography, or EUS, has joined medical techniques of endoscopy with high frequency ultrasound technique, known as ultrasound. This removable achievement allows physician for microscopic tissue examination, not only in digestive system, but also in its surroundings by highly frequent technique. Endoscopic ultrasonography detects all kinds and nature of possible abnormalities, including and information, which are necessary for proper diagnosis and optimal treatment. In experience hands, EUS can detect abnormalities, which are undetectable during any other techniques of examination. EUS is applied from inside the body, near or even touching the examined surface, so the precise, highly frequent energy of showing the images can be used. The sonography, MRI, CT techniques must show the inner organs through outside surface of body, loosing the resolution during process. The superior resolution of EUS shows 5 layers of digestive tract, almost equally good as by microscope; none of other techniques allows showing of intestinal wall equally good as this one. By EUS liquid has been proved with 90% of precision in diagnosis of operative degrees of pancreas tumours. CT in this case has shows only 50% of precision. Highly skilled surgeons are aware of application of these diagnostics techniques in preoperative cases so the surgical removement of tumours is going to be more effective. The precision of EUS findings are of critical importance for the utilisation of maximum of new treatment having in mind that abnormalities could be diagnosed and characterised without operative intervention. To be able to focus on specific anatomic surfaces, there is need of great knowledge, skillfulness and praxis during the manipulation with EUS instrument. The years of experience are needed to be able to achieve high standard of expertise. The accuracy of results varies, depending on physicians diagnostic experience, sub-optimal results are not going to be a good guide during treatment planning. Endosonographist must be in position to document at least 80% of accuracy in diagnosis and determination of disease stage in order to achieve 30-60% changes in plans treatment.

Digestive System↗
PubMed2006

LEAD: a methodology for learning efficient approaches to medical diagnosis.

Determining the most efficient use of diagnostic tests is one of the complex issues facing medical practitioners. With the soaring cost of healthcare, particularly in the US, there is a critical need for cutting costs of diagnostic tests, while achieving a higher level of diagnostic accuracy. This paper develops a learning based methodology that, based on patient information, recommends test(s) that optimize a suitable measure of diagnostic performance. A comprehensive performance measure is developed that accounts for the costs of testing, morbidity, and mortality associated with the tests, and time taken to reach diagnosis. The performance measure also accounts for the diagnostic ability of the tests. The methodology combines tools from the fields of data mining (rough set theory, in particular), utility theory, Markov decision processes (MDP), and reinforcement learning (RL). The rough set theory is used in extracting diagnostic information in the form of rules from the medical databases. Utility theory is used in bringing various nonhomogenous performance measures into one cost based measure. An MDP model together with an RL algorithm facilitates obtaining efficient testing strategies. The methodology is implemented on a sample problem of diagnosing solitary pulmonary nodule (SPN). The results obtained are compared with those from four alternative testing strategies. Our methodology holds significant promise to improve the process of medical diagnosis.

Algorithms↗
PubMed1998

Percent free prostate-specific antigen in assessing the probability of prostate cancer under optimal analytical conditions.

Although general consensus exists that percent free prostate-specific antigen (PSA) is superior to total immunoreactive PSA for prostate cancer (CaP) detection, its diagnostic performance is not yet well established. Analytical problems may account for difficulties in evaluating percent free PSA because the free PSA concentration is substantially lower than that of total PSA. The aim of the present study was to establish the diagnostic performances of the IMMULITE percent free PSA assay from Diagnostics Products Corp. under experimental conditions optimized to minimize analytical variability. Eighty-five patients with untreated primary CaP and 261 with untreated benign prostate hypertrophy (BPH) were prospectively enrolled. The Diagnostics Products IMMULITE total (Third Generation) and free PSA were measured by the same technician, using the same instrument and the same reagent batch. We calculated the post-test probability to express how the likelihood of the diagnosis of CaP changed after the percent free PSA was determined. Areas under the ROC curves of percent free PSA were better than those of total PSA in every evaluated range of total PSA. The percent free PSA could have reduced the rate of unnecessary biopsies by 47% in patients with total PSA >/=4 microg/L with only 3.8% false-negative results. The post-test probability of percent free PSA was, however, <50% in men 50-70 years of age, using cutoff points providing sensitivity from 99% to 80%. Percent free PSA is superior to total PSA in distinguishing primary CaP from BPH in patients with total PSA between 2 and 30 microg/L. In men with low total PSA, the diagnostic performance of the percent free PSA assay may be optimized by controlling methodological variability. The percent free PSA assay is effective in reducing the rate of unnecessary biopsies in men with total PSA >4 microg/L. However, the post-test probability provided by percent free PSA is relatively low in asymptomatic patients 50-70 years of age.

Aged↗
PubMedDate not supplied

Endoscopic and endosonographic management of pancreatic pseudocyst: a long-term follow-up.

BACKGROUND: The cause of pancreatic cyst were in 72 % due to alcoholism. A drainage to pancreatic cyst is very critical for patient with the stomach varices patient. The endoscopic ultrasonography(EUS) is a valuable supplement to the diagnostic procedure to localise the optimal spot for puncture and to avoid haemorrhage due to damage of intra or extra-mural blood vessels. METHODS: The drainage was reached by transpapillary endoscopic retrograde pancreatic drainage (ERPD), endoscopic cystogastrostomy (ECG) or endoscopic cystoduodenostomy (ECD). The case that varices is doubted and If the identification of the cyst is difficult the transmural drainage should be carried out under endosonographic control. RESULTS: Between 1987 and 2002, 47 patients had been treated for panceatic pseudocysts by transmural or transductal drainage EUS-guided drainage of a pancreatic pseudocyst or pancreatc abscess was carried out in 5 cases. In 42patients pancreatic pseudocysts disappeared completely. Six patients suffered a relapse 7 to 38 months after removal of the drainage. No more recurrences were observed in 22 patients within followed up 5-11 years. In another 6 patients the prostheses were renewed because of occlusion or dislocation. Overall 6 patients had to undergo surgery, 3 patients due to relapsing cyst, 2 patients because of insufficient drainage and one patient because of severe bleeding. There was no case of death related to the endoscopic treatment. CONCLUSION: The EUS is a valuable supplementation to the diagnostic procedure to localize the optimal spot for puncture and to avoid haemorrhage because of damage of intra or extramural bloodvessels. Advantages of the endoscopic drainage are minimal invasiveness, short period of hospitalization and low costs. These aspects make the endoscopic therapy the first choice of treatment of pancreatic pseudocysts.

Adolescent↗
PubMed1997

Virtual reality in the operating room of the future.

In cooperation with the Max-Delbrück-Centrum/Robert-Rössle-Klinik (MDC/RRK) in Berlin, the Fraunhofer Institute for Computer Graphics is currently designing and developing a scenario for the operating room of the future. The goal of this project is to integrate new analysis, visualization and interaction tools in order to optimize and refine tumor diagnostics and therapy in combination with laser technology and remote stereoscopic video transfer. Hence, a human 3-D reference model is reconstructed using CT, MR, and anatomical cryosection images from the National Library of Medicine's Visible Human Project. Applying segmentation algorithms and surface-polygonization methods a 3-D representation is obtained. In addition, a "fly-through" the virtual patient is realized using 3-D input devices (data glove, tracking system, 6-DOF mouse). In this way, the surgeon can experience really new perspectives of the human anatomy. Moreover, using a virtual cutting plane any cut of the CT volume can be interactively placed and visualized in realtime. In conclusion, this project delivers visions for the application of effective visualization and VR systems. Commonly known as Virtual Prototyping and applied by the automotive industry long ago, this project shows, that the use of VR techniques can also prototype an operating room. After evaluating design and functionality of the virtual operating room, MDC plans to build real ORs in the near future. The use of VR techniques provides a more natural interface for the surgeon in the OR (e.g., controlling interactions by voice input). Besides preoperative planning future work will focus on supporting the surgeon in performing surgical interventions. An optimal synthesis of real and synthetic data, and the inclusion of visual, aural, and tactile senses in virtual environments can meet these requirements. This Augmented Reality could represent the environment for the surgeons of tomorrow.

Computer Simulation↗
PubMed2005

3.0 vs 1.5 T MRI in the detection of focal cartilage pathology--ROC analysis in an experimental model.

OBJECTIVE: To use receiver operator characteristics (ROC) analysis for assessing the diagnostic performance of three cartilage-specific MR sequences at 1.5 and 3 T in detecting cartilage lesions created in porcine knees. DESIGN: Eighty-four cartilage lesions were created in 27 porcine knee specimens at the patella, the medial and lateral femoral and the medial and lateral tibial cartilage. MR imaging was performed using a fat saturated spoiled gradient echo (SPGR) sequence (in plane spatial resolution/slice thickness: 0.20 x 0.39 mm2/1.5 mm) and two fat saturated proton density weighted (PDw) sequences (low spatial resolution: 0.31 x 0.47 mm2/3 mm and high spatial resolution: 0.20 x 0.26 mm2/2 mm). The images were independently analyzed by three radiologists concerning the absence or presence of lesions using a five-level confidence scale. Significances of the differences for the individual sequences were calculated based on comparisons of areas under ROC curves (A(Z)). RESULTS: The highest A(Z)-values for all three radiologists were consistently obtained for the SPGR (A(Z) = 0.84) and the high-resolution (hr) PDw (A(Z) = 0.79) sequences at 3T. The corresponding A(Z)-values at 1.5 T were 0.77 and 0.69; the differences between 1.5 and 3 T were statistically significant (P < 0.05). A(Z)-values for the low-resolution PDw sequence were lower: 0.59 at 3 T and 0.55 at 1.5 T and the differences between 1.5 and 3T were not significant. CONCLUSION: With optimized hr MR sequences diagnostic performance in detecting cartilage lesions was improved at 3 T. For a standard, lower spatial resolution PDw sequence no significant differences, however, were found.

Animals↗
PubMed2000

Can we improve the diagnostic efficiency and predictive power of prodromal symptoms for schizophrenia?

Prodromal symptoms and other variables for a sample of 200 young people who had experienced a first-onset functional psychosis, were analyzed to examine their diagnostic efficiency and predictive power in relation to a diagnosis of schizophrenia. Two different techniques were utilized to generate optimal cut-off points for a number of prodromal symptoms, and optimal decision rules to maximize diagnostic efficiency. The product of the chance-corrected sensitivity and specificity, or the area under the QROC curve, was used to assess the predictive efficiency of a number of prodromal variables, DSM-III-R prodromal variables, pre-psychotic deterioration, pre-morbid functioning, and prodromal duration. The SPAN technique generated a decision rule that performed equivalently to the single variable 'duration of prodrome'. Implications of these results for future research are discussed.

Adolescent↗
PubMed2002

Usefulness of prostate-specific antigen velocity in screening for prostate cancer.

BACKGROUND: The cut-off value of prostate-specific antigen velocity (PSAV) was investigated in relation to the initial prostate-specific antigen (PSA) value in subjects with initial values of 1.0-4.0 ng/mL, and the usefulness and limitations of PSAV as a screening test for prostate cancer were examined. METHODS: In this study, 4883 men who underwent mass screening for prostate cancer two or more times between 1987 and 1998 and had initial PSA levels of 1.0-4.0 ng/mL were investigated. The subjects ranged in age from 42 to 96 years (mean: 68.0 +/- 6.6 years). The cut-off value of PSAV was set at 0.1-1.5 ng/mL per year, and the sensitivity, specificity, efficiency and positive predictive value (PPV) of PSAV for detecting prostate cancer were determined according to the initial PSA value. A similar examination of the average PSAV was carried out in 2888 subjects with three or more visits for mass screening for prostate cancer. RESULTS: The diagnostic efficiency of PSAV was optimal with cut-off values of 0.3 and 0.75 ng/mL per year in those subjects with initial PSA levels of 1.0-1.9 and 2.0-4.0 ng/mL, respectively, but the PPV was low at 1.8% in subjects with initial PSA levels of 1.0-1.9 ng/mL. When the cutoff value of PSAV was set at 1.2 ng/mL per year in individuals with initial PSA levels of 1.0-1.9 ng/mL, the PPV increased to 7.3% and the sensitivity was 40%. The diagnostic efficiency of the average PSAV was optimal at the cut-off values of 0.2 and 0.4 ng/mL per year in subjects with initial PSA levels of 1.0-1.9 and 2.0-4.0 ng/mL, respectively, but the PPV was low at 2.2% in the subjects with initial PSA values of 1.0-1.9 ng/mL. When the cut-off value of PSAV was set at 0.75 ng/mL per year in individuals with initial PSA levels of 1.0-1.9 ng/mL, the PPV was 9.8% and the sensitivity was 46%. CONCLUSION: It is possible to improve the diagnostic accuracy of prostate cancer screening using the cut-off value of PSAV and average PSAV in subjects with initial PSA levels of 1.0-4.0 ng/mL. The cut-off values of PSAV should be set at 1.2 and 0.75 ng/mL per year in individuals with initial PSA levels of 1.0-1.9 and 2.0-4.0 ng/mL, respectively. The cut-off values of the average PSAV should be set at 0.75 and 0.4 ng/mL per year in individuals with initial PSA levels of 1.0-1.9 and 2.0-4.0 ng/mL, respectively.

Adult↗
PubMed1997

Warping CT scans from nontreatment to treatment position.

This paper describes a cost-effective technique that optimally utilizes all available diagnostic studies for three-dimensional treatment planning. A simulator unit modified to produce cross-sectional images (simulator-CT unit) is used to create a reference data set with the patient in the treatment position. Registration software (qsh) brings other diagnostic studies into agreement with this reference data set. Two cases are presented as examples of the use of this technique. Registration of abdominal scans from the same patient demonstrates the warping of a nontreatment position study to the treatment position. The second case is based on paired data sets through the head, in which the diagnostic study was obtained by using a gantry tilt to follow the base of the skull and to avoid sections passing through the teeth. The registration software provides a method for combining diagnostic studies into a single "master" data set. The success of the transformation depends on the operator's ability to identify corresponding anatomic landmarks for different data sets and on the magnitude of the variation in the patient's position from one procedure to the next. Limitations in image quality and the number of cross-sections obtainable from a simulator-CT unit can be partially overcome by using the described technique. Thus, the information contained in nontreatment position diagnostic tests can be used accurately for treatment planning at limited cost.

Anatomy, Cross-Sectional↗
PubMed2002

Capillary electrophoresis for detection of inherited disorders of purine and pyrimidine metabolism: a selective approach.

We developed a capillary electrophoresis method as a diagnostic tool for purine and pyrimidine metabolic disorders. Optimal conditions allowed the separation of the major diagnostic metabolites in urine samples within an analysis time of 10 min and with a separation efficiency of about 350,000 theoretical plates/m. The diagnostically important metabolites (adenine, adenosine, 2-deoxyadenosine, 2-deoxyguanosine, 2,8-dihydroxyadenine, guanosine, hypoxanthine, orotidine, orotic acid, and creatinine) were detectable at concentrations of 1.0-5.7 micromol/L. The method gives a linear calibration curve for tested purine and pyrimidine derivatives within the range of 5-500 micromol/L (r > 0.996) The coefficients of variation for the within- and between-day imprecisions were less than 3.2 and 5.8%, respectively. Characteristic abnormalities were detected in the electropherograms of urine samples from patients with purine and pyrimidine enzyme deficiencies. We provide electrophoretic and spectral characteristics of intermediates in purine and pyrimidine metabolism and possible artifacts from medication and their UV-absorbing compounds. Our method allows the detection of the majority of inborn errors of purine and pyrimidine metabolism.

Adolescent↗
PubMed2002

Development of the Korean version of Alzheimer's Disease Assessment Scale (ADAS-K).

OBJECTIVE: The purpose of this study was the development of the Korean Version of Alzheimer's Disease Assessment Scale (ADAS-K). METHOD: ADAS-K was administrated to 84 AD patients as well as 105 non-demented control subjects. Three aspects of reliability were tested. To evaluate the validity of ADAS-K, discriminant validity and concurrent validity were tested. To evaluate the sensitivity of ADAS-K to disease severity, all subjects, AD patients and control subjects, were grouped by CDR scale and their mean scores on ADAS-K were compared. RESULT: ADAS-K demonstrated high levels of reliability. Mean ADAS-K scores for AD patients were significantly different from the control group (p < 0.01). Furthermore, ADAS-K exhibited significant correlations with other tests and scales (range 0.45-0.85, p < 0.01). In ROC curve analysis, ADAS-K displayed high diagnostic efficacy and the optimal cut-off point was selected between 18/19. ADAS-K was able to discriminate the degree of AD severity according to CDR classification. Our results suggested that ADAS-K-cog was sensitive to very mild AD. CONCLUSION: We demonstrated that ADAS-K is a reliable and valid instrument not only for AD diagnosis but also for evaluation of its severity.

Aged↗
PubMed2005

Arrhythmogenic right ventricular cardiomyopathy. Antiarrhythmic drugs, catheter ablation, or ICD?

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a major cause of sudden cardiac death and ventricular tachyarrhythmias in young, apparently healthy individuals and athletes. Myocardial atrophy with subsequent fibrofatty replacement predominantly affects right ventricular myocardium and results in global and regional dysfunction as well as areas of slow conduction and dispersion of refractoriness which are prerequisites for reentrant ventricular tachyarrhythmias. Patients affected with ARVC should be excluded from competitive sports and vigorous training. To provide optimal treatment, a detailed diagnostic evaluation and risk stratification are mandatory. Tailored treatment strategies aim at the suppression or effective termination of recurrent ventricular tachyarrhythmias and prevention of sudden death by antiarrhythmic drug therapy, catheter ablation, or implantation of a cardioverter defibrillator (ICD). Antiarrhythmic drugs may be used as a stand-alone treatment to suppress ventricular tachycardia (VT) recurrences in patients with ARVC and low risk of sudden death. Sotalol (preferred) or amiodarone in combination with beta-blockers showed the highest efficacy rates. In patients at higher risk, an ICD should be implanted and antiarrhythmic drugs be used only as an adjunct to prevent or suppress frequent VT recurrences and ICD discharges. Catheter ablation using conventional or electroanatomic mapping techniques yields good acute results for eliminating the targeted arrhythmia substrate. However, during the progressive long-term course of ARVC, VT recurrences from new arrhythmia foci are frequent and therefore limit the curative value of catheter ablation. In patients with frequent VT recurrences and ICD discharges, however, catheter ablation plays an important role as a palliative and adjunctive treatment option for arrhythmia suppression. ICD therapy has been increasingly used for secondary and also primary prevention of sudden death in patients with ARVC. In secondary prevention, the ICD has shown to improve the long-term prognosis of patients at high risk of sudden death by effective termination of life-threatening recurrences of ventricular tachyarrhythmias. However, adequate lead placement may be difficult and lead-related complications during long-term follow-up must be taken into account. The role of ICD therapy for primary prevention of sudden death in ARVC is not yet adequately defined. Ongoing international registries will provide important additional data to improve risk stratification and refine treatment algorithms in order to select the best individual treatment for arrhythmia suppression and prevention of sudden death in patients with ARVC.

Anti-Arrhythmia Agents↗
PubMed2001

[The role of diagnostic PET in treatment planning before tumor surgery].

Positron emission tomography (PET) can be used for the noninvasive biochemical analysis of lesions whose benign or malignant nature cannot be assessed by morphological methods alone. This information and the possibility of quantitation are the reasons for the successful application of PET in staging, diagnosis of tumor recurrence and therapy monitoring in different malignant tumors. Since malignant tumors show characteristic biochemical properties with an enhancement of glucose metabolism, 18fluorodeoxyglucose (FDG) has proven useful for oncologic studies. This paper deals with the influence of PET on the surgical and other therapeutic procedures in patients with cancer of the lung, thyroid, intestine, breast and soft tissue. PET is useful for the mediastinal staging of patients with lung cancer and the evaluation of persistent tissue or tumor recurrence after treatment of lung cancer and colorectal cancer. Furthermore, important information is obtained for the staging of colorectal cancer and mammary carcinoma. PET is also indicated in patients with colorectal cancer or mammary carcinoma and a rising tumor marker. An important future application is therapy monitoring. New treatment modalities will raise new problems in terms of functional diagnosis for the different imaging procedures. Therefore, future work has to concentrate on the establishment of diagnostic algorithms for the optimization of therapy.

Breast Neoplasms↗