[The possible benefit of artificial intelligence in an organized population-related screening program : Initial results and perspective]. / Der mögliche Nutzen künstlicher Intelligenz in einem organisierten bevölkerungsbezogenen Screeningprogramm : Erste Ergebnisse und Ausblick.

BACKGROUND: Mammography screening programs (MSP) have shown that breast cancer can be detected at an earlier stage enabling less invasive treatment and leading to a better survival rate. The considerable numbers of interval breast cancer (IBC) and the additional examinations required, the majority of which turn out not to be cancer, are critically assessed. OBJECTIVE: In recent years companies and universities have used machine learning (ML) to develop powerful algorithms that demonstrate astonishing abilities to read mammograms. Can such algorithms be used to improve the quality of MSP? METHOD: The original screening mammographies of 251 cases with IBC were retrospectively analyzed using the software ProFound AI® (iCAD) and the results were compared (case score, risk score) with a control group. The relevant current literature was also studied. RESULTS: The distributions of the case scores and the risk scores were markedly shifted to higher risks compared to the control group, comparable to the results of other studies. CONCLUSION: Retrospective studies as well as our own data show that artificial intelligence (AI) could change our approach to MSP in the future in the direction of personalized screening and could enable a significant reduction in the workload of radiologists, fewer additional examinations and a reduced number of IBCs; however, the results of prospective studies are needed before implementation.

Radiation dose reduction in computer assisted navigation for functional endoscopic sinus surgery--cadaver head experiments and clinical implementation.

OBJECTIVES: Computed tomography based navigation for endoscopic sinus surgery is inflationary used despite of major public concern about iatrogenic radiation induced cancer risk. Studies on dose reduction for CAS-CT are almost nonexistent. We validate the use of radiation dose reduced CAS-CT for clinically applied surface registration. METHODS: Dose reduced CAS-CT of mineral salt fixed, human cadaver heads with 9.6, 6, 4, 2 and 1.1 mGy were compared with the reference dose at 65 mGy CTDI (CT-Dose Index). For each CT dose with different surface resolution, the precision of the soft touch registration was measured with target registration error (TRE). In a practical step, dose reduced protocols were tested for 12 months. RESULTS: Using surface registration at highest and lowest doses, TRE did not differ significantly for registration accuracy. Protocols tested preserved technical registration accuracy and the pragmatics of dose reduction was limited only by different needs for picture quality of the individual surgeon, use for uncomplicated or revision surgery, and reserve for other unexpected factors (movement artifacts). CONCLUSIONS: The accuracy of today's surface registration technology was not the limit for dose reduction. It is the amount of diminished picture quality tolerated by the individual surgeon and the question of how much of the ever refined radiological picture resolution is necessary at all. For the majority of operations, consensus for a significant 6-fold radiation dose reduction from 65 mGy to 9.6 mGy CTDI could be realized illustrating a big potential for similar approaches in other institutions.

Closure of an open drug scene--a case register-based analysis of the impact on the demand for methadone maintenance treatment.

AIMS: To assess the impact of the closure of an open drug scene on the demand for methadone maintenance treatment (MMT). DESIGN: Interrupted time series analysis of case register-based data of all MMTs performed in the canton of Zurich (Switzerland) between June 16 1992 and July 7 1997. SETTING: Five private and 14 state-controlled institutions as well as 330 general practitioners, 35 psychiatrists, and 79 other specialists offering outpatient MMT. PARTICIPANTS: 5210 opiate users with 9042 MMT episodes. MEASUREMENTS: Monthly number of entries into MMT before, during and after the closure of the Letten scene in February 1995, MMT retention rates, participants' socio-demographic and drug-related data. FINDINGS: ARIMA modelling revealed 68 (95% CI = 31-105; p < 0.001) additional MMT admissions due to the dispersion of the open drug scene without a decrease in MMT retention rates. Socio-demographic and drug-related characteristics of patients entering MMT in the month of the closure did not significantly differ from other admissions. CONCLUSIONS: Law enforcement strategies to eliminate open drug scenes may increase the demand for MMT. Sufficient treatment facilities for opioid dependence should be provided when law enforcement activities against open drug scenes are planned.

[Bladder and rectal infiltration by uterine carcinomas: the accuracy of CT and MRI compared to endoscopic procedures]. / Blasen- und Rektuminfiltration durch Uteruskarzinome: Treffsicherheit der CT und der MRT im Vergleich zu endoskopischen Verfahren.

PURPOSE: To establish the value of computed tomography (CT) and magnetic resonance imaging (MRI) in predicting bladder and rectum involvement in uterine carcinoma. MATERIAL AND METHODS: 6 different imaging signs (focal obliteration of perivesical or perirectal fat planes, area and angle of contact between uterus and bladder or rectum, asymmetric bladder or rectum wall thickening, evidence of intraluminal masses, and signal intensity of bladder or rectum wall on T2-weighted or contrast-enhanced MR images) were analysed retrospectively in 129 patients who underwent 92 CT and/or 64 MRI examinations. The data were correlated with intraoperative findings and the results of cystoscopy and rectoscopy. RESULTS: Asymmetric wall thickening, evidence of intraluminal masses and increased signal intensities of the bladder wall or rectum wall were valuable signs of infiltration (sensitivity 71-100%, specificity 91-96% and accuracy 89-97%). In 27 patients submitted to both imaging examinations MRI was somewhat superior compared to CT (p > 0.1) and yielded similar results as endoscopic procedures (accuracy of cystoscopy and rectoscopy of 90% and 94%, respectively). CONCLUSION: CT and MRI allow to predict involvement of bladder or rectum wall in carcinoma of the uterus with a similar accuracy as endoscopic procedures.

[Antiaggregation: aspirin]. / Antiaggregation--Aspirin.

Many randomized trials have shown aspirin as an effective antiplatelet drug for the secondary prevention of cardiovascular events. The NNT (number needed to treat) to prevent 1 vascular event is about 25. The NNH (number needed to harm) inducing one cerebral bleeding is about 1'000, to provoke one severe extracerebral bleeding about 100-200. The primary prevention can be recommended only for high risk patients for cardiovascular events (annual risk of 1-1.5% or more), calculated on the basis of the Framingham data, the Sheffield tables or in analysis of U.S. Preventive Services Task Force. The mechanisms of action, interactions and the "aspirin-resistance" are briefly discussed.

[Assessment of parathyroid gland function: predictive value of a nomogram]. / Beurteilung der Nebenschilddrüsenfunktion: Aussagekraft eines Nomogramms.

Recent developments in measurement of intact parathormone (PTH) has enabled to generate a nomogram for parathyroid function. Blood levels of PTH can thus be interpreted in relation to calcemia. Intact PTH and calcium were assayed in blood from 99 healthy subjects studied under fasting conditions; 26 subjects were also studied during hyper- and hypocalcemia, induced by calcium and EDTA infusions, respectively. Serum levels of intact PTH which had been obtained in 99 patients were then analysed retrospectively by comparison with the nomogram. Patients whose intact PTH levels lie above the normal zone of the nomogram produce too much PTH relative to the blood calcium level (hyperparathyroidism); those falling under the normal zone produce too little (hypoparathyroidism).

CT radiation dose for computer-assisted endoscopic sinus surgery: dose survey and determination of dose-reduction limits.

BACKGROUND AND PURPOSE: Computer-assisted navigation is increasingly used in functional endoscopic sinus surgery (FESS) to prevent injury to vital structures, necessitating preparative CT and, thus, radiation exposure. The purpose of our study was to investigate currently used radiation doses for CT in computer-assisted navigation in sinus surgery (CAS-CT) and to assess minimal doses required. MATERIALS AND METHODS: A questionnaire inquiring about dose parameters used for CAS-CT was sent to 30 radiologic institutions. The feasibility of low-dose registration was tested with a phantom. The influence of CAS-CT dose on technical accuracy and on the practical performance of 5 ear, nose, and throat (ENT) surgeons was evaluated with cadaver heads. RESULTS: The questionnaire response rate was 63%. Variation between minimal and maximal dose used for CAS-CT was 18-fold. Phantom registration was possible with doses as low as 1.1 mGy. No dose dependence on technical accuracy was found. ENT surgeons were able to identify anatomic landmarks on scans with a dose as low as 3.1 mGy. CONCLUSIONS: The vast dose difference between institutions mirrors different attitudes toward image quality and radiation-protection issues rather than being technically founded, and many patients undergo CAS-CT at higher doses than necessary. The only limit for dose reduction in CT for computer-assisted endoscopic sinus surgery is the ENT surgeon's ability to cope with impaired image quality, whereas there is no technically justified lower dose limit. We recommend, generally, doses used for the typical diagnostic low-dose sinus CT (120 kV/20-50 mAs). When no diagnostic image quality is needed, even a reduction down to a third is possible.

Comparison of self-ratings and therapist ratings of outpatients' psychosocial status.

In psychiatric treatment, differences between therapists' observer ratings and patients' self-ratings are well known. We studied these differences in a sample of chronically mentally ill outpatients. The results show that the patients rated their psychosocial status significantly better than their therapists. By means of multiple regression analysis, we designed a model to explain the specific differences. By placing more emphasis on leisure activities and less emphasis on addictive behavior, compliance, and psychopathology, therapists might predict global ratings given by patients more accurately. This model helps therapists obtain a better understanding of their patients.

Effects of electrical stimulation of low-threshold muscle afferents on visual reaction time.

Human subjects performed plantar flexions of the foot in visual reaction time (RT) situations. In the simple RT task, the same foot had to be moved during the whole session, in the choice RT task, the right or left foot was moved in a random sequence. Low-threshold muscle afferents which evoked a monosynaptic H reflex were electrically activated on both sides at various intervals after the onset of the light stimulus. In both RT situations. RT was shortened equally by the electrical stimulation. The intersensory facilitation in the choice RT task provided support for the preparation enhancement model, since the subjects could not react to the electrical stimulus alone.

Relation between the specific H reflex facilitation preceding a voluntary movement and movement parameters in man.

In a reaction-time situation, the monosynaptic spinal reflex (H reflex) is facilitated before the onset of an electromyographic (e.m.g.) response. The aim of the present investigation was to study aspects of this facilitation. Human subjects were required to perform isometric plantarflexions of the foot in response to a visual stimulus. The movement was always on the same side in the simple reaction-time situation, and randomly with the right or left foot in the choice reaction-time situation. Stimuli to evoke H reflexes were applied bilaterally 40-400 ms after the onset of the visual stimulus. Pre-motor time, i.e. the interval between the onset of the visual stimulus and the e.m.g. response, and reaction time, i.e. the interval between the onset of the visual stimulus and the response on the torque recording, were computed. In both reaction-time situations, there was a significant facilitation of the ipsilateral H reflex 100-160 ms before e.m.g. onset and, in some subjects, a small facilitation of the contralateral H reflex. The specific facilitation, i.e. the difference between the facilitation on the ipsi- and contralateral side relative to the movement, was not significantly different on the right and left side. Pre-motor time was divided into the interval from the light onset until the onset of the specific facilitation, and the interval from the onset of the facilitation until the onset of the voluntary response. Both intervals increased, and the slope and the amplitude of the facilitation decreased with increasing pre-motor time and reaction time. The specificity of the H reflex facilitation in a choice reaction-time situation implies that the interval from light onset until the onset of the facilitation includes stimulus identification and response selection, and the interval from the onset of the facilitation until the e.m.g. response preparation of the motor system for the required movement. The present results suggest that the specific facilitation of the H reflex before a movement is caused by removal of presynaptic inhibition at I a terminals or by activation of interneurones intercalated in polysynaptic components of the H reflex rather than by a subthreshold activation of motoneurones.

Stimulation of erythropoietin in renal insufficiency by hypobaric hypoxia.

Patients with renal anaemia show inadequate levels of immunoreactive erythropoietin (Epo) related to the degree of anaemia. The purpose of our study is to compare the degree of stimulation of Epo by means of hypobaric hypoxia in normal controls and patients with renal anaemia. Baseline Epo concentrations were found to be 11.1 +/- 2.0 U/l in 10 healthy volunteers and 11.4 +/- 4.6 U/l in six patients with renal anaemia. After exposure to hypobaric hypoxia equivalent to 4560 m above sea level for a duration of 3.5 h, we observed a significant increase in serum Epo in healthy volunteers to 22.8 +/- 9.1 U/l (P < 0.005), while there was no increase in patients with renal anaemia: 12.3 +/- 5.2 U/l (P < 0.2). Our results show that in patients with renal anaemia serum Epo concentrations are comparable to those of normal controls, but inadequate in view of the concomitant degree of anaemia. Stimulation by acute hypobaric hypoxia was not possible in patients with renal insufficiency as opposed to normal controls. From these data it can be concluded that either Epo production is working at maximum capacity under baseline conditions, or an additional hybobaric stimulus is not able to influence a disturbed set point of the oxygen sensor regulating Epo synthesis.

Detection of reaction time by an adaptive filter based on the least squares fit.

An adaptive filter based on the least squares fit between a template and individual records was developed. It has been applied to compute reaction times of a voluntary movement. Its performance was tested by comparing these reaction times with the latency of the EMG responses. Different properties of the least squares fit technique and Woody's filter technique (Woody 1967) are discussed.

[How quickly do the effects of sector division appear? The initial results of the companion research of the Zurich sector division project]. / Wie rasch zeigen sich Sektorisierungseffekte? Erste Resultate aus der Begleitforschung des Züricher Sektorisierungsprojektes.

Dividing the delivery system of larger psychiatric hospitals into defined smaller catchment areas called sectors, implies a contribution to quality assurance. Continuous monitoring and evaluation of a period before and after this reorganisation, which took place in 1994 for the central region of Zürich (Psychiatric University Hospital), allows perception of expected and possible unexpected changes. All newly registered patients were recorded within a time span divided into five periods of six month five each, the last one covering the first six months after sectorisation. This design permits to answer the question as to how fast the intended changes after sectorisation occur, and also to control side effects. Results show that sectorisation resulted in a marked increase of registrations from the defined catchment area of each sector, and that the investigated institutions achieve attainment of the aim to effect a special selection of psychiatric patients characterised by considerable psycho-social deficits. The two sectors display differences in respect of socio-demographic characteristics of newly registered patients.

Magnetic resonance imaging of the heart and the great vessels: morphology, function, and perfusion.

The capability of MR imaging to evaluate cardiovascular disease is developing faster than ever, as is well documented by the numerous contributions that have been made to the literature during the past year. As the field progresses, MR imaging will probably become one of the preferred investigational methods for the evaluation of cardiac function. The first stage of MR imaging development emphasized replication of commonly used methods for studying morphology and analyzing global ventricular performance. Thus, validated MR imaging methods exist for the assessment of ventricular' volume, ejection fraction, and mean wall stress. More recently, emphasis has been directed toward the evaluation of regional function and perfusion, using novel methods and attracting increasing interest from the cardiovascular research community. Studies reviewed here focus on both clinical results obtained using well-established MR imaging techniques and new results using innovative methods, further extending the usefulness of MR imaging. Topics discussed include congenital and ischemic heart disease and disease of the great vessels. Technical advances in flow and velocity mapping and in the evaluation of ventricular performance are also discussed.

Aortic valve pressure gradients in patients with aortic valve stenosis: quantification with velocity-encoded cine MR imaging.

OBJECTIVE: Pressure gradients across the aortic valve due to stenosis of the valve must be measured accurately to evaluate the functional severity of the stenosis. Velocity-encoded cine MR has been used to quantify blood flow and flow direction and, more recently, the regurgitant fraction in aortic regurgitation. The purpose of this study was to determine the feasibility and accuracy of velocity-encoded cine MR for estimating pressure gradients across the aortic valve in patients with aortic stenosis. SUBJECTS AND METHODS: We used velocity-encoded cine MR to measure flow velocity and determine pressure gradients across the aortic valve in 19 subjects. The pressure gradient (delta P) was estimated from the simplified Bernoulli equation by using the maximum instantaneous aortic jet velocity (Vmax): delta P (mm Hg) = 4V2max (m/sec). RESULTS: Maximum and mean systolic pressure gradients determined by using velocity-encoded cine MR were 3-148 mm Hg and 2-87 mm Hg, respectively, for all subjects. The pressure gradients correlated closely with gradients determined by using established methods: Doppler echocardiography and cardiac catheterization. Correlation coefficients (r) were .96 (y = 0.94x - 1.9) and .97 (y = 0.97x + 0.5), respectively. CONCLUSION: We conclude that velocity-encoded cine MR imaging provides a noninvasive and accurate means for quantifying the severity of valvular aortic stenosis. MR is a feasible method for determining pressure gradients across the aortic valve.

Detection of liver metastases: comparison of superparamagnetic iron oxide-enhanced and unenhanced MR imaging at 1.5 T with dynamic CT, intraoperative US, and percutaneous US.

PURPOSE: To compare the sensitivities of superparamagnetic iron oxide-enhanced and unenhanced magnetic resonance (MR) imaging at 1.5 T with those of percutaneous ultrasound (US), intraoperative US (IOUS), and dynamic computed tomography (CT) in the preoperative assessment of metastatic liver disease. MATERIALS AND METHODS: Eighteen patients with liver metastases who were candidates for curative surgery underwent presurgical imaging. Thirteen patients underwent surgery and IOUS after undergoing preoperative US, CT, and MR imaging. RESULTS: In the preoperative imaging group, the standard of reference was the total number of lesions detected with any of the modalities. Superparamagnetic iron oxide-enhanced MR imaging was the most sensitive modality (99%). In the surgical group, the standard of reference was the total number of metastases identified at IOUS and pathologic examination. IOUS had the highest sensitivity (80%), followed by superparamagnetic iron oxide-enhanced MR imaging (56%). CONCLUSION: Superparamagnetic iron oxide-enhanced high-field-strength MR imaging facilitates the preoperative evaluation of potentially curable metastatic liver disease; however, it is inferior to IOUS.

[Vocational rehabilitation of the mentally ill - an evaluation of the Vocational Rehabilitation Center in Zurich, Switzerland]. / Integration psychisch Kranker in die Arbeitswelt - Evaluation des Berufsförderungskurses Zürich

OBJECTIVE: The aim of the Vocational Rehabilitation Center in Zurich (VRC) is to reintegrate mentally ill persons into the primary labour market, mainly by prevocational training followed by continuous professional support for employed individuals. The present study evaluated the impact of the VRC. METHODS: The job and financial situation of 68 trained persons was assessed up to two years after the training. Additionally, their vocational history and sociodemographic data were analysed. RESULTS: Before the training, only 9 % had a job, while two years after the course 42 % were employed in competitive jobs. On the other hand, using an ordinal scale, two years after the training, 78 % of the patients were found in a better job situation than before the course. Likewise, the financial situation of 52 % of the clients has improved within those two years. The strongest correlation with success was the intensity of support after the training. CONCLUSIONS: The VCR is effective in training mentally ill patients for the primary job market. Continuous professional support is vital for ongoing success.

Which individuals with affective symptoms seek help? Results from the Zurich epidemiological study.

OBJECTIVE: Several factors influence whether individuals with affective disorders seek help. The Zurich cohort study provides an opportunity to explore patient-based factors without confounding with problems of access. This study aims to identify features which predict help-seeking behaviour in symptomatic individuals and to explore failure of help seeking in those who did not. METHOD: Characteristics of currently symptomatic 40-year-old individuals in a stratified epidemiological sample were tested against help-seeking behaviour using bivariate statistics and logistic regression. Individual predictors were identified and interaction effects tested. RESULTS: Thirty-one per cent of the 364 subjects sought help in the preceding year. Past treatment and living alone were significantly associated with treatment. Total number of symptoms and several individual symptoms correlated with treatment in the bivariate analyses but regression analysis identified "unfounded self-reproach" and "hopelessness" interacting with social support to predict the best treatment. CONCLUSION: Social support is strongly protective against needing help in the presence of distressing affective symptoms unless these symptoms become elaborated into conclusions about their meaning and prognostic significance.

Morbid obesity and postoperative pulmonary atelectasis: an underestimated problem.

UNLABELLED: Perturbation of respiratory mechanics produced by general anesthesia and surgery is more pronounced in morbidly obese (MO) patients. Because general anesthesia induces pulmonary atelectasis in nonobese patients, we hypothesized that atelectasis formation would be particularly significant in MO patients. We investigated the importance and resorption of atelectasis after general anesthesia in MO and nonobese patients. Twenty MO patients were anesthetized for laparoscopic gastroplasty and 10 nonobese patients for laparoscopic cholecystectomy. We assessed pulmonary atelectasis by computed tomography at three different periods: before the induction of general anesthesia, immediately after tracheal extubation, and 24 h later. Already before the induction of anesthesia, MO patients had more atelectasis, expressed in the percentage of the total lung area, than nonobese patients (2.1% versus 1.0%, respectively; P < 0.01). After tracheal extubation, atelectasis had increased in both groups but remained significantly more so in the MO group (7.6% for MO patients versus 2.8% for the nonobese; P < 0.05). Twenty-four hours later, the amount of atelectasis remained unchanged in the MO patients, but we observed a complete resorption in nonobese patients (9.7% versus 1.9%, respectively; P < 0.01). General anesthesia in MO patients generated much more atelectasis than in nonobese patients. Moreover, atelectasis remained unchanged for at least 24 h in MO patients, whereas atelectasis disappeared in the nonobese. IMPLICATIONS: We compared the resolution over time of pulmonary atelectasis after a laparoscopic procedure by performing computed tomography scans in two different groups of patients: 1 group had 10 nonobese patients, and in the other group there were 20 morbidly obese patients.