Expert opinion on the use of transvaginal sonography for presurgical staging and classification of endometriosis.

Gynecological ultrasonography plays a central role in the management of endometriosis. The rapid technical development as well as the currently increasing evidence for non-invasive diagnostic methods require an updated compilation of recommendations for the use of ultrasound in the management of endometriosis. The present work aims to highlight the accuracy of sonography for diagnosing and classifying endometriosis and will formulate the present list of key messages and recommendations. This paper aims to demonstrate the accuracy of TVS in the diagnosis and classification of endometriosis and to discuss the clinical applications and consequences of TVS findings for indication, surgical planning and assessment of associated risk factors. (1) Sophisticated ultrasound is the primary imaging modality recommended for suspected endometriosis. The examination procedure should be performed according to the IDEA Consensus. (2) Surgical intervention to confirm the diagnosis alone is not recommended. A preoperative imaging procedure with TVS and/or MRI is strongly recommended. (3) Ultrasound examination does not allow the definitive exclusion of endometriosis. (4) The examination is primarily transvaginal and should always be combined with a speculum and a bimanual examination. (5) Additional transabdominal ultrasonography may enhance the accuracy of the examination in case of extra pelvic disease, extensive findings or limited transvaginal access. (6) Sonographic assessment of both kidneys is mandatory when deep endometriosis (DE) and endometrioma are suspected. (7) Endometriomas are well defined by sonographic criteria. When evaluating the ovaries, the use of IOTA criteria is recommended. (8) The description of sonographic findings of deep endometriosis should be systematically recorded and performed using IDEA terminology. (9) Adenomyosis uteri has sonographically well-defined criteria (MUSA) that allow for detection with high sensitivity and specificity. MRI is not superior to differentiated skilled ultrasonography. (10) Classification of the extent of findings should be done according to the #Enzian classification. The current data situation proves the best possible prediction of the intraoperative situs of endometriosis (exclusive peritoneum) for the non-invasive application of the #Enzian classification. (11) Transvaginal sonographic examination by an experienced examiner is not inferior to MRI diagnostics regarding sensitivity and specificity in the prediction of the extent of deep endometriosis. (12) The major advantage of non-invasive imaging and classification of endometriosis is the differentiated planning or possible avoidance of surgical interventions. The recommendations represent the opinion of experts in the field of non-invasive and invasive diagnostics as well as therapy of endometriosis. They were developed with the participation of the following national and international societies: DEGUM, ÖGUM, SGUM, SEF, AGEM/DGGG, and EEL.

Objective Assessment of Cervical Stiffness after Administration of Misoprostol for Intrauterine Contraceptive Insertion.

PURPOSE: The goal of this study was to objectively quantify cervical stiffness in misoprostol users prior to IUC insertion and at follow-up consultation to evaluate the feasibility of assessing cervical stiffness and to study the influence of misoprostol on cervical softening. MATERIALS AND METHODS: This was a cross-sectional study that evaluated 40 women who wished to use the LNG IUS. These women were evaluated immediately before LNG IUS insertion and 6 weeks later at follow-up consultation. Participants received 200 µg of misoprostol combined with 75 mg of diclofenac in a single tablet orally (Arthrotec forte 75/200(®), Pfizer, USA) 6-12 h prior to insertion in "off label" use. On both occasions, cervical stiffness was determined using a novel medical device based on the aspiration technique. The Wilcoxon rank-sum and the Wilcoxon signed-rank test were applied to compare cervical stiffness assessments at insertion of the IUD and at follow-up. RESULTS: For the first time, cervical stiffness was quantitatively assessed in misoprostol users prior to IUD insertion, proving that the aspiration technique enables detection of pharmacologically induced cervical changes, and also that misoprostol has a detectable softening effect on cervical tissue. CONCLUSION: The clinical value of the detected cervical softening after misoprostol administration remains unclear. Aspiration measurements could be helpful in searching for the ideal candidate, the appropriate route, dosage and interval of misoprostol intake prior to IUC insertion.

Challenging the in-vivo assessment of biomechanical properties of the uterine cervix: A critical analysis of ultrasound based quasi-static procedures.

Measuring the stiffness of the uterine cervix might be useful in the prediction of preterm delivery, a still unsolved health issue of global dimensions. Recently, a number of clinical studies have addressed this topic, proposing quantitative methods for the assessment of the mechanical properties of the cervix. Quasi-static elastography, maximum compressibility using ultrasound and aspiration tests have been applied for this purpose. The results obtained with the different methods seem to provide contradictory information about the physiologic development of cervical stiffness during pregnancy. Simulations and experiments were performed in order to rationalize the findings obtained with ultrasound based, quasi-static procedures. The experimental and computational results clearly illustrate that standardization of quasi-static elastography leads to repeatable strain values, but for different loading forces. Since force cannot be controlled, this current approach does not allow the distinction between a globally soft and stiff cervix. It is further shown that introducing a reference elastomer into the elastography measurement might overcome the problem of force standardization, but a careful mechanical analysis is required to obtain reliable stiffness values for cervical tissue. In contrast, the maximum compressibility procedure leads to a repeatable, semi-quantitative assessment of cervical consistency, due to the nonlinear nature of the mechanical behavior of cervical tissue. The evolution of cervical stiffness in pregnancy obtained with this procedure is in line with data from aspiration tests.

[Cystic adnexal mass]. / Zystischer Unterbauchtumor.

Confirmation and clarification of an adnexal mass is a domain of transvaginal ultrasound. The highest hit ratio is achieved by experienced sonographers relying on a dedicated set of sonomorphologic criteria. Less experienced may consult validated scores, colour doppler findings and the tumor marker CA125. The assignment to one of the three groups simple cyst, benign tumor, malign tumor should lead to an adequate procedure (control, laparoscopy, laparotomy). Whenever possible to avoid unnecessary surgical interventions, simple cysts should be treated conservatively. Also in postmenopausal woman 50% of them resolve spontaneously in 60 days. Ovarian cancer screening is still an unsolved problem. Nearly all established methods fail because of the low prevalence of ovarian cancer at around 0.4%.

Modeling intravasation of liquid distension media in surgical simulators.

During therapeutic hysteroscopy and transurethral resection of the prostate, intravasation of the liquid distension media into the vascular system of the patient occurs. We present a model which allows the integration of the intravasation process into surgical simulator systems. A linear network flow model is extended with a correction for non-Newtonian blood behavior in small vessels and an appropriate handling of vessel compliance. We employ a fast lookup scheme in order to allow for real-time simulation. Cutting of tissue is accounted for by adjusting pressure boundary conditions for all cut vessels. We investigate the influence of changing distention fluid pressure settings and of the position of tissue cuts. In addition, we quantify the intravasation occurring with different approaches of fluid control, and we compare the performance of direct and iterative solvers applied to the non-linear system of the compliant model. Our simulation predicts significant intravasation only on the venous side, and just in cases when larger veins are cut. The implemented methods allow the realistic control of bleeding for short-term and of the total resulting intravasation volume for long-term complication scenarios. While the simulation is fast enough to support real-time training, it is also adequate for explaining intravasation effects which were previously observed on a phenomenological level only.

Modelling intravasation of liquid distension media in surgical simulators.

We simulate the intravasation of liquid distention media into the systemic circulation as it occurs during hysteroscopy and transurethral resection of the prostate. A linear network flow model is extended with a correction for non-newtonian blood behaviour in small vessels and an appropriate handling of vessel compliance. We then integrate a fast lookup scheme in order to allow for real-time simulation. Cutting of tissue is accounted for by adjusting pressure boundary conditions for all cut vessels. We investigate the influence of changing distention fluid pressure settings and of the position of tissue cuts. Our simulation predicts significant intravasation only on the venous side, and just in cases when larger veins are cut. The implemented methods allow the realistic control of bleeding for short-term and the total resulting intravasation volume for long-term complication scenarios. While the simulation is fast enough to support real-time training, it is also adequate for explaining intravasation effects which were previously observed on a phenomenological level only.

[Gynecologic ultrasound in the acute abdomen--the predominant reasons]. / Akutes Abdomen aus gynäkolo- gisch-sonographischer Sicht - Eine Darstellung der häufigsten Ursachen.

In gynecological settings, a sensible approach to diagnosing acute abdomen or lower abdominal pain is to classify the cases into positive pregnancy tests (if the patient is known to be pregnant) and negative pregnancy tests (or if the patient is postmenopausal). Various forms of ectopic pregnancy and abortion are associated with early pregnancy. Once a pregnancy has been excluded, diagnostics should focus on pain in conjunction with adnexal findings, adnexal torsions, fibroids and infections. Sonography for evaluating morphology and blood circulation to organs and structures has a high diagnostic value, but should always be judged together with medical history, clinical, laboratory and any other imaging findings. Indeed, abdominal pain requires intensive interdisciplinary collaboration. Not rarely, there are several relevant causes of lower abdominal pain.

Tumor growth models to generate pathologies for surgical training simulators.

Many virtual reality based surgical training simulators have been presented in the last few years. These systems promise to alleviate the lack of realistic training possibilities common to minimally invasive procedures. Virtual reality allows for riskless training on a wide range of findings in a condensed period of time. We investigated different methods for the generation of tumor models suitable for surgical training simulators. The goal of our research is a high fidelity hysteroscopy simulator which provides an individual surgical scene for every training. Emphasis was placed on the modeling of growth processes leading to the generation of macroscopically realistic findings of the most common pathologies in hysteroscopy, namely polyps and myomas found in the uterine cavity. Both a cellular automaton and a particle based tumor growth model are presented and discussed.

Generation of variable anatomical models for surgical training simulators.

The generation of variable surgical scenes is a key element for effective training with surgery simulators. Our current research aims at a high fidelity hysteroscopy simulator which challenges the trainee with a new surgical scene in every training session. We previously reported on methods able to generate a broad range of pathologies within an existing healthy organ model. This paper presents the methods necessary to produce variable models of the healthy organ. In order to build a database of uteri, a volunteer study was conducted. The segmentation was carried out interactively, also covering the establishment of an anatomically meaningful correspondence between the individual organs. The variability of the shape parameters has been characterized by principal component analysis. A new method has been developed and tested, allowing the derivation of realistic new instances based on the stochastic model and complying with non-linear shape constraints which are defined and interactively controlled by medical experts.

[Contraception and bleeding disorders--diagnostic contributions by ultrasound]. / Kontrazeption und Blutungsstörungen--Beitrag der Sonographie.

Practically all widely used and safe and reversible methods of contraception exert a direct (or at least an indirect) impact on the endometrium. Not surprisingly, abnormal uterine bleeding is a frequent adverse reaction associated with contraception. In this situation sonography--in particular transvaginal sonography--offers the physician a practically non-invasive imaging technique for determining the etiology of abnormal uterine, cervical or vaginal bleeding. Ultrasonographic imaging provides the physician with a detailed picture of the internal reproductive organs. It can also be used to monitor the efficacy of the particular contraceptive method. e.g. to check the position of IUDs, confirm the suppression of ovarian follicle activity in women taking ovulation inhibitors, detect ovarian cysts as a focus of undesirable hormonal activity, etc. In some cases, the failure of contraception, namely pregnancy, can be diagnosed by ultrasound. By using high-frequency linear ultrasonographic probes, the physician can verify the position of subcutaneous contraceptive implants on the medial upper arm. Therapeutic consequences can be derived, in particular, from the ultrasonographic measurement of the total thickness of the endometrial layer.

Hydrometra simulation for VR-based hysteroscopy training.

During hysteroscopy a hydrometra is maintained, i.e. the uterus is distended with liquid media to access and visualize the uterine cavity. The pressure and flow induced by the liquid are crucial tools for he gynecologists during surgery to obtain a clear view of the operation site. This paper presents two different aspects of hydrometra simulation, namely the distension of the uterine muscle and the liquid flow simulation in the cavity. The deformation of the organ's shape is computed offline based on finite element calculations whereas the flow is approximated on the fly by solving the simplified Navier-Stokes equations. The real-time capabilities of the presented algorithms as well as the level of fidelity achieved by the proposed methods are discussed.

A finite element model for the simulation of hydrometra.

The behaviour of the human uterus under an internal (intracavital) pressure of 150 mm Hg (20 kPa) was modelled. The application of such an intracavital or intrauterine pressure corresponds to the procedure which is performed at the beginning of hysteroscopy (hydrometra). Homogenous, isotropic material laws were implemented in a three dimensional, finite element model. The volume of the distended uterine cavity was calculated with different parameters obtained from in vivo aspiration experiments on human uteri as well as from ex vivo tensile tests on rabbit uteri for comparison purposes. The calculated results were in general agreement with in vivo measurements of hydrometra performed at the University Hospital of Zurich.

[Differential diagnosis of acute pelvic pain in gynecology]. / Differentialdiagnose von akuten Unterbauchschmerzen in der Gynäkologie.

Differential diagnosis of acute pelvic pain in gynecology has to respect the four pillars anamnesis, laboratory, clinical investigation and ultrasonographic evaluation. Besides, no findings should be evaluated independently. A meaningful general attempt to the diagnostics in gynecology is the partitioning in pregnancy test-positive (known pregnancy respectively) and pregnancy test-negative (postmenopausal respectively). Further important findings are clear inflammation markers and free blood in the abdominal cavity. If an extensive basic clarification should not allow conclusive diagnosis, the judgement of the dynamism of the complaints by short term controls or an interdisciplinary cooperation may be helpful. Sometimes, several relevant causes may be identified as reason of acute pelvic pain.

Detailed anatomy of the abdomen and pelvis of the visible human female.

We report on a virtual anatomical preparation of the abdomen and pelvis of the Visible Human Female (VHF) for laparoscopic surgery training. The detailed cross-sectional image data set from the U.S. National Library of Medicine was used as the basis to build an exemplary model of the female abdomen and pelvis. Segmentation software was developed to delineate organ outlines and more than 300 structures of interest, including organs, blood vessels, bones, muscles, and ligaments, have been segmented and three-dimensionally reconstructed. Analyzing the normal anatomy we found several variations and pathologies of the VHF, such as missing muscles (gemellus superior, psoas minor), additional veins as well as spondylophytes (vertebral column, pubic bone), and colon diverticula. The complete data set may be viewed on the home page of the project (http://www.vision.ee.ethz.ch/projects/Lasso/start.html).

New nomogram for foetal weight estimation based on Hadlock's two-parameter formula.

AIM: To develop and validate a graphical method for ultrasonic foetal weight estimation with predictive qualities comparable to state-of-the-art computational methods. METHOD: Study data were obtained from 3839 consecutive singleton pregnancies with ultrasound examination within 7 days of delivery. We translated the well established Hadlock 2-parameter formula based on abdomen circumference and femur length into a nomogram [corrected]. We compared the measured foetal weight with estimations obtained from this new nomogram and three other methods. RESULTS: Measured by the foetal weight percentage error the new nomogram underestimates the foetal weight on average by 2.5 % (9.86) (mean [SD]) with uniform results over the complete birth weight spectrum. By the same measurement the Hadlock 4-parameter formula underestimates the foetal weight by 1.2 % (9.3) whereas the Hansmann nomogram overestimates the foetal weight by 14.5 % (16.1) The difference between the estimated foetal weight percentage error obtained from the new nomogram and from the Hadlock 2-parameter formula is 0.06 % (0.27) and hence clinically irrelevant. CONCLUSION: The new nomogram has predictive qualities comparable to state-of-the-art computational methods and is thus not only as reliable but also easy to use in situations when computers are not available. It can be recommended for foetal weight estimation over the whole spectrum of birth weight.

Inverse finite element characterization of soft tissues.

In this work a tissue aspiration method for the in vivo determination of biological soft tissue material parameters is presented. An explicit axisymmetric finite element simulation of the aspiration experiment is used together with a Levenberg-Marquardt algorithm to estimate the material model parameters in an inverse parameter determination process. An optimal fit of the simulated experiment and the real experiment is sought with the parameter estimation algorithm. Soft biological tissue is modelled as a viscoelastic, non-linear, nearly incompressible, isotropic continuum. Viscoelasticity is accounted for by a quasi-linear formulation. The aspiration method is validated experimentally with a synthetic material. In vivo (intra-operatively during surgical interventions) and ex vivo experiments were performed on human uteri.

[Ultrasound endometrium follow-up during tamoxifen treatment: Really not reliable or useful after all?]. / Sonographische Endometriumkontrolle unter Tamoxifen: Wirklich nicht empfehlenswert oder doch sinnvoll?

AIM: To investigate whether an examination of the endometrium of women treated with tamoxifen (TAM) is useful or not. METHOD: 40 breast cancer patients who displayed a thickened endometrium of > 8 mm and/or vaginal bleeding were included in the study. They received daily TAM adjuvantly. Histologic clarification by hysteroscopy and D&C was recommended for patients with an endometrium of > 8 mm or vaginal bleeding. RESULTS: In our collective, the mean endometrial thickness was 13.7 +/- 5.6 mm (SD). 32 patients underwent a histological examination. Most had a benign lesion; in 2 cases we merely found a cystic atrophy (11 mm, 18 mm), 2 displayed atypical tissue (13 mm, 25 mm) and 2 an endometrial cancer (19 mm, 33 mm). All patients with atypical tissue or cancer had an endometrial thickness markedly above the norm, but 3 of them were not bleeding. No linear correlation between thickness of the endometrium and duration of TAM intake was found. CONCLUSION: To detect early premalignant or malignant changes of the endometrium, we recommend histological examination by hysteroscopy and dilatation and curettage when the endometrium is > 8 mm thick, even in the absence of symptoms. Therefore, these patients should have regular examinations by transvaginal ultrasound once or twice a year. Moreover, continuing regular screening of the endometrium for years after termination of tamoxifen-therapy is also to be recommended.

[Adnexal findings]. / Adnexbefunde.

The female small pelvis is usually explored by conventional clinical examination. Adnexal masses found are assessed first by ultrasound. Thereby, sonographic findings should be documented and committed in a purely descriptive manner. It is not advisable to establish a histopathologic diagnosis, but to assign sonographic findings to one of the following three major groups: "simple cyst", "benign lesion", "malignant lesion". The SGUMGG recommends the Mainz-Score for the assessment of adnexal tumours, performed by transvaginal ultrasonography. Usually, a new adnexal tumour without symptoms may be evaluated after an interval of approx. six weeks without additional danger for the patient. A comprehensive Swiss guideline to adnexal tumours is in preparation by the Schweizerische Gesellschaft für Gynäkologie und Geburtshilfe. Its release is expected to be in the ongoing year 2001.

Virtual reality based surgery simulation for endoscopic gynaecology.

Virtual reality (VR) based surgical simulator systems offer very elegant possibilities to both enrich and enhance traditional education in endoscopic surgery. However, while a wide range of VR simulator systems have been proposed and realized in the past few years, most of these systems are far from able to provide a reasonably realistic surgical environment. We explore the basic approaches to the current limits of realism and ultimately seek to extend these based on our description and analysis of the most important components of a VR-based endoscopic simulator. The feasibility of the proposed techniques is demonstrated on a first modular prototype system implementing the basic algorithms for VR-training in gynaecologic laparoscopy.

[Krukenberg syndrome in metastatic gallbladder adenocarcinoma with unknown primary tumor]. / Krukenberg Syndrom bei metastasierendem Gallenblasenadenokarzinom mit inapparentem Primärtumor.

The casuistic describes a female patient, in whom a metastatic adenocarcinoma of the ovary was diagnosed 3 years after cholecystectomy due to cholecystolithiasis, which was compatible with metastases of a carcinoma of the gallbladder or the bile ducts. While clinical and imaging results suggested a primary ovarian carcinoma with inapparent primary tumor, the final diagnosis was obtained on the basis of histological findings. The case demonstrates that an ovarian metastasis can simulate a primary tumor according to clinical and imaging results. This fact can be of serious therapeutic consequences for the respective patient. Therefore, in the presence of a clinically inapparent primary tumor, the differential diagnosis of unclear ovarian masses should include metastatic adenocarcinoma in addition to primary ovarian carcinoma and other ovarian lesions.