A z gain nonuniformity correction for multislice volumetric CT scanners.

This paper presents a calibration and correction method for detector cell gain variations. A key functionality of current CT scanners is to offer variable slice thickness to the user. To provide this capability in multislice volumetric scanners, while minimizing costs, it is necessary to combine the signals of several detector cells in z, when the desired slice thickness is larger than the minimum provided by a single cell. These combined signals are then pre-amplified, digitized, and transmitted to the system for further processing. The process of combining the output of several detector cells with nonuniform gains can introduce numerical errors when the impinging x-ray signal presents a variation along z over the range of combined cells. These numerical errors, which by nature are scan dependent, can lead to artifacts in the reconstructed images, particularly when the numerical errors vary from channel-to-channel (as the filtered-backprojection filter includes a high-pass filtering along the channel direction, within a given slice). A projection data correction algorithm has been developed to subtract the associated numerical errors. It relies on the ability of calibrating the individual cell gains. For effectiveness and data flow reasons, the algorithm works on a single slice basis, without slice-to-slice exchange of information. An initial error vector is calculated by applying a high-pass filter to the projection data. The essence of the algorithm is to correlate that initial error vector, with a calibration vector obtained by applying the same high-pass filter to various z combinations of the cell gains (each combination representing a basis function for a z expansion). The solution of the least-square problem, obtained via singular value decomposition, gives the coefficients of a polynomial expansion of the signal z slope and curvature. From this information, and given the cell gains, the final error vector is calculated and subtracted from the projection data.

A dose reduction x-ray beam positioning system for high-speed multislice CT scanners.

The introduction of multislice CT scanners and the associated dose increase compared to single and dual slice scanners has concerned many radiologists, health and medical physicists, as well as members of the regulatory community. Since multislice CT scanners are inherently post-patient collimated, they are less dose efficient than single slice CT scanners, which use prepatient collimation. The x-ray beam must be wide enough in the Z axis so that the beam remains on the detector in spite of typical movements due to thermal and mechanical flexing. We describe the x-ray beam tracking system that is employed on a GE LightSpeed QX/i scanner to substantially reduce the multislice dose. The tracking system stabilizes the beam on the detector allowing a narrower x-ray exposure profile compared to the x-ray exposure profile without tracking. The tracking system measures the position of the beam every few milliseconds and continually repositions a source aperture to hold a narrow beam fixed on the detector. Using a standard LightSpeed QX/i source collimator and segmented detector, dose reductions of up to 40% were measured when tracking was employed. We also show that tracking has the potential to provide a dose efficiency approaching single slice scanners.

[Postoperative complications and work disability after operation on the adnexa per laparotomy and after pelviscopic surgery]. / Postoperatives Beschwerdebild und Arbeitsunfähigkeit nach Adnex-operation per laparotomiam und nach pelviskopischen Operationen.

For estimations of the complaint pattern after comparatable operations per pelviscopiam versus per laparotomiam, in a retrospective study 114 patients after pelviscopic operation and 117 patients after laparotomy were examined. The most important significant differences with an advantage for the pelviscopycally operated patients had been found in asking for postoperative spontaneous miction (84.2% versus 37.2%), spontaneous defecation (68.0% versus 8.1%), the time of completely being free from pain when climbing stair (11.9 compared to 20.8 days), the time when the patient absolutely feel no pain any longer (15.8 compared to 51.7 days), in the average hospitalisation time (3.8 compared to 8.9 days) and the time for unfitness for work (24.5 compared to 48.7 days). Under consideration that also after pelviscopic operations pain occur which are to be treated the present studies confirm the clear improvement of life quality pelviscopic operations.

[Neonatal percentile values for the GDR--1985. Correlation of body weight and length in newborn infants (calculation of birth weight/body length in cm. with reference to gestational age)]. / Neugeborenenperzentilwerte für die DDR--1985. Zur Korrelation von Gewicht und Länge bei Neugeborenen (Berechnung des Geburtsgewichtes/cm Körperlänge unter Berücksichtigung des Gestationsalters).

Taking account of the gestational age (28th to 42nd completed week of pregnancy) the sex-related ratio of birth weight to length (g/cm) for newborn infants is reported. This shows that observation of the correlation between birth weight and length with reference to gestational age makes a more accurate classification of newborn infants possible, rather than using a two dimensional classification (birth weight week of gestation).

[Attitude and sex behavior following hysterectomy]. / Zum Befinden und Sexualverhalten nach Hysterektomie.

488 women have been asked after abdominal or vaginal hysterectomy by way of retrospective questionnaires about preoperative anxieties, postoperative psychosomatic complaints as well as disturbances of their vita sexualis. 48.6% of the patients had anxieties before operation and anaesthesia. After hysterectomy 71.9% of the women reported about hot flushes and other psycho-vegetative complaints. Although hot flushes occurred significantly more frequent in patients with salpingooophorectomy they could be observed also in one third of the women without removal of the ovaries. However libido, cohabitation frequency and orgasm ability were reduced significantly more frequent in the group of women after hysterectomy with salpingooophorectomy. This is caused by the failing blood supply to the ovary via the branches of the uterine artery. The reduce postoperative psychosomatic complaints as well as sexual dysfunctions it is important to give qualited instructions before and after the operation. On no account should a prophylactic exstirpation of the adnexa be carried out before the age of 50 years. A hormonal substitution is recommended to be done in time even for patients whose ovaries have not been removed suffering from psycho-somatio discomforts.

[Intrauterine growth retardation--CTG findings in pre-partum oxygen respiration and transcutaneous nerve stimulation]. / Intrauterine Wachstumsretardierung--CTG-Befunde bei präpartaler Sauerstoffatmung und transkutaner Nervenstimulation.

In 33 pregnant women with sonographic diagnosis intrauterine growth retardation (IUGR) 75 O2-mask respirations or, for a comparison, 63 transcutaneous electric paravertebral nerve stimulations (TENS) were carried out between 30 to 39 weeks of gestation. Before, during and after these measures the fetus was monitored by means of continuous CTG-registration. Both in the O2-inhalations and in the TENS the dominant CTG-changes were the rise of the acceleration frequency (in about 41% respectively 49% of the measures) and the increase of the fetal movements (in about 35% respectively 64% of the measures). In the case of some O2-respirations prognostically unfavourable CTG-changes occurred, like fetal tachycardia (in 9 experiments) and firstly occurring decelerations (in 8 experiments), Spikes not being taken into consideration. As those CTG-changes were also seen in some cases with TENS it is concluded that these findings were caused by retardation and that most probably O2-respiration cannot be charged with. Additionally a report is given on nuclearmedical measurements of the uteroplacental blood circulation and on determinations of the concentration of the serumal oxytocinase. The present study shows that by O2-respiration in connection with IUGR obviously no acute risk for the fetus exists which could be proved in the CTG. However it permits no conclusion on the therapeutic effect.

[The East German Twin Study l984/85. Report of selected aspects]. / DDR-Gemini-Studie 1984/85. Bericht über Teilaspekte.

Analysis of a multicentre study of the GDR in which 67 clinics with a total of 1,200 twin pairs participated over a scheduled period of 18 months. In the result a recommendation for the antenatal, intrapartal and neonatal care of gemini-pregnancy was prepared.

[Diagnosis and surgical therapy of suppurative inflammations of the adnexa]. / Zur Diagnostik und operativen Therapie abszedierender Adnexentzündungen.

A report is given on 119 patients suffering from abscessforming adnexitis, mainly tubo-ovarian abscesses (40.3%) and pyosactosalpinges (38.7%). These women were operated on within the first 24 hours after admission to the hospital. Before the operation was performed 70.6% of the women had been submitted to laparoscopy. The other ones (28.4%) had unequivocal primary sign of the disease. Laparoscopic diagnosis is recommended because especially in the early phase of abscess formation no clear diagnosis by clinical examination and paraclinical findings is possible. Operation as early as possible in case of formation of a tubo-ovarian abscess is recommended by reason of the good experience and results which become apparent by small intra- and post-operative complication rate of 1.7% respectively, the short hospital stay of 12.8 days and the short time of risamblement of 53 days. The extent of the operation should depend on degree of severity of the illness, reproductive aspects.

[Second-look laparoscopy--results and pregnancy rate in patients with a state of laparoscopically assessed acute adnexitis]. / Second-look-Laparoskopie--Ergebnisse und Schwangerschaftsrate bei Patientinnen mit Zustand nach laparoskopisch gesicherter akuter Adnexentzündung.

A report is given on the findings of second-look-laparoscopy in 229 patients with condition after laparoscopically ascertained and classified inflammations of the adnexes which were treated on the basis of uniform criteria. We also want to report about the pregnancy rate dependent upon the degree of severity of the inflammation in 121 patients. It could be proved with absolute certainty that there was a dependence of the frequency of pathologic changes of the tubes with negative chromopertubation on the degree of severity of the preceding illness and also on the kind of the causative organisms. The most frequent pathologic findings came up after advanced fibrinous-suppurative inflammations as well as after gonorrhoic inflammations of the adnexes, the latter not depending on the degree of severity. The pregnancy rate, 1-5 years after treated salpingitis, for patients having the wish to deliver a child, came to 72.5% after serous salpingitis, 72.2% after operation of the adnex on one side and 59.1% after fibrinous-suppurative salpingitis. In connection with the demand for general laparoscopic diagnostics of the inflammable illnesses of the adnexes it is important to point to the necessity of early registration and treatment as well as to the cultural diagnostics of gonorrhoea. In the case of abscesses of the adnexes on one side and wish to deliver a child immediate operation is recommended.(ABSTRACT TRUNCATED AT 250 WORDS)

[Computer-assisted screening for cervical carcinoma--the results for a 10-year period]. / Computergestütztes Screening auf Zervixkarzinom--Ergebnisse einer 10-Jahresperiode.

A report is given of 10 years experiences with a computer assisted mass-screening-programme to detect pre-stages and early stages of cervical carcinoma in Rostock city. The participation in the age-groups up to 40 years was over 75%. With this programme it is possible to make statistical analysis, to control the quality of Pap-smears and colposcopical results and to identify the risk-group of unscreened women for special examinations. As a result of the programme a decrease of cervical carcinomas since 1980 of about 25% was noticed. The same situation was found in pre-stages. Inert of all registered cervical carcinomas the number of stage one-cases increased.

[Analysis of 35,013 gynecologic laparoscopies (East German survey). 1]. / Analyse von 35 013 gynäkologischen Laparoskopien (DDR-Umfrage). 1. Mitteilung.

Statistic from 81 women hospitals in which a total of 35,013 laparoscopies had been made figures were collected by means of questionnaires (inquiry forms). The largest increase of laparoscopies (56.2%) could be found since 1980. Results showed that in 48 hospitals (59.3%) less than 50 laparoscopies were made per year. In all hospitals laparoscopy was performed under clinical conditions by the gynaecologist, mainly using endotracheal anesthesia (96.3%). 20 hospitals (24.7%) are able to perform laparoscopies in the day-time only. More than 90% of the questioned ones regarded thoracic roentgenogram, electrocardiogram as well as urine examination and hemoglobin determination as sufficient pre-examinations. 70.4% of the questioned hospitals demand a written confirmation that before the operation was carried out appropriate instructions had been given. The technical performance of laparoscopy corresponds to today's usual practice. For the pneumoperitoneum, for which 51.8% of the hospitals use an automatic system, CO2 (6.7%) is preferred. Patients are dismissed from hospital on 1st (19.8%), 2nd (50.6%) or 3rd day after the operation and later in 29.5% of the cases. Women are unable to work for an average of eight days following laparoscopy.

[Analysis of 35,013 gynecologic laparoscopies (East German survey). 2]. / Analyse von 35 013 gynäkologischen Laparoskopien (DDR-Umfrage). 2. Mitteilung.

In 81 women's hospital, in which 35,013 gynaecological laparoscopies were made, 42.9% of the specialists are able to perform laparoscopies by themselves. 51.9% of the questioned hospital directors recommend learning how to perform laparoscopies during specialization, and 48.1% plead for laparoscopy training only for gynaecologic specialists. 64.2% of the questioned ones were in favour of laparoscopy courses. Performance of diagnostic laparoscopies was recommended for all gynaecological institutions by 82.7%. In the opinion of the majority (74.8%) operative laparoscopies should be done only in larger central hospitals. It was generally agreed that chronic diseases of the lower abdomen, sterility and suspected ectopic pregnancy are indications for laparoscopy. Other acute complaints have been diagnosed less frequently by means of laparoscopy. Second-look-laparoscopies were made by 59.3% and 55.6% of the questioned doctors, mainly for checking the situation operations because of ovarian cancer and sterility. In 61.1% of all hospitals other diagnostic and therapeutic operations per laparoscopiam are done. The rate of severe complications was 0.21%, and the mortality rate amounted to 0.057%.

[Telemetric labor monitoring. Clinical aspects, cardiotocographic findings and acceptance of free mobilization in labor]. / Telemetrische Geburtsüberwachung. Klinische Aspekte, kardiotokographische Befunde und Akzeptanz der freien Mobilisation unter der Geburt.

Telemetric signal transmission represents a suitable technical concept for combining free mobilisation with continuous electronic monitoring of birth. The obstetric aspect of telemetric birth monitoring is discussed on the basis of a clinical-statistical analysis: a group of 127 women in labour (64 primigravidae and 63 multigravidae) were examined and the specific effect of mobilisation on obstetrically relevant parameters was analysed. The results show the advantages of this method of birth management. Freedom of decision as regards choice of posture during birth, better subjective control and less painful labour, better birth mechanics, more effective labour, shorter duration of birth, better heart-rate patterns, optimal exterior conditions and an active basic attitude of the woman in labour are the proven advantages of this method. The highly significant relationship between the degree of mobilisation and the duration of birth is emphasised as one of the most important results.

[Initial experiences with the operative treatment of tubal pregnancy by laparoscopy]. / Erste Erfahrungen mit der operativen Behandlung der Tubargravidität per laparoscopiam.

First experiences and results in 14 tubal pregnancies are reported operated on by laparoscopy. In 11 cases the tubes were removed. In 3 patients there was a conservative operation with preservation of the tubes. A laparotomy had to be done in one patient for a hemorrhage from the mesosalpinx. Duration of stay in the hospital lasts from 4 to 5 days. Second-look-laparoscopies of 9 patients whose fallopian tubes had been removed resulted in 7 normal findings. In two cases there were adhesions between omentum majus and uterus on that side operated on. Following expressions of the gestational sac in two patients there was one normal tube and in the other one slight peritubal adhesions. Two patients who were operated on conservatively had been delivered afterwards.

[The "long-term morbidity" computer program in perinatology. 1. Program introduction]. / Computer-Programm "Langzeit-Morbidität" in der Perinatologie 1. Mitteilung: Programmvorstellung.

Presentation of the Computer-programme for prospective analysis of morbidity of unselected children born in 1983 up to 1985 over a period of 10 years.

[Compatible receiver insert for telemetric monitoring of labor]. / Kompatibler Empfänger-Einschub zur telemetrischen Geburtsüberwachung.

A receiver-insert for telemetric monitoring of childbirth, which is compatible with the monitoring system of VEB Messgerätewerk Zwönitz, is presented.

[Experiences with a mobile monitoring system for fetal and neonatal cardiotachometry]. / Erfahrungen mit einem mobilen Monitorsystem zur fetalen und neonatalen Kardiotachometrie.

A monitoring system for fetal and neonatal cardiotachometry which set up in own instrumentation at the Department of obstetrics of the Regional Hospital of Rostock. With aid of a wireless telemetric system is it possible to estimate the fetal condition before and during of caesarean section as well as at transfer of high risk neonates.