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C Hessler

Publications and source records attributed to C Hessler.

At least 19 recordsLinked to original sources
PubMed1996

Survey on image quality and dose levels used in Europe for mammography.

Quality assurance programmes are becoming a common practice in the field of mammography. At the present time several recommendations exist and different test objects are used to optimize this radiological procedure. The goal of this study was to check if geographically distant centres using different quality control procedures were comparable when using a common objective way of assessing image quality. The results show that consensus still needs to be found among radiologists to reach a satisfactory level of harmony between patient doses and image quality in Europe.

Europe↗
PubMed1995

Traumatic chest lesions in patients with severe head trauma: a comparative study with computed tomography and conventional chest roentgenograms.

In patients with severe craniocerebral trauma, who need a continuous positive-pressure breathing, the detection of pulmonary and mediastinal traumatic lesions, especially pneumothorax, may alter the management. The aim of this study is to evaluate the efficiency and accuracy of conventional supine chest roentgenograms to detect the associated traumatic chest lesions in severe craniocerebral trauma and to compare their value as a diagnostic method for the identification of unsuspected lesions with a limited chest computed tomographic (CT) examination. Forty-seven consecutive patients with severe craniocerebral trauma underwent head CT and a prospective limited CT examination of the thorax in the same session. Nine patients (19.1%) presented a pneumothorax, bilateral in one case. Six pneumothoraces (60%) were identified both on conventional chest roentgenograms and CT, whereas in four cases (40%), the lesion was only detectable on CT. The CT study also showed 31 areas of pulmonary parenchymal contusions in 19 subjects (40%), whereas the conventional chest roentgenograms demonstrated 17 areas of contusions in 11 (23%) subjects. One thoracic aorta and one right diaphragm rupture were detected on CT study. On the conventional chest roentgenograms the mediastinal vascular injury was overlooked, whereas the right diaphragmatic rupture was highly suspected. The limited chest CT examination supplied additional information in 30% of patients. In 12.7% of patients, this information was clinically significant enough to alter the management. In patients with severe craniocerebral trauma evaluation of associated chest trauma by a supplementary limited chest CT, examination provides more and precise information about the size and severity of mediastinal and pulmonary lesions with a superior detectability of pneumothorax.

Adolescent↗
PubMed1993

Facial thermography during nasal provocation tests with histamine and allergen.

Changes of skin temperature (T degree) of the nose area during nasal provocation tests with histamine and allergen were followed by means of an infrared thermography camera. By a colimator system in which temperatures measured on a given surface can be integrated and averaged, thermography allows the continuous and quantitative recording of the temperature during the whole procedure in a completely noninvasive way. In 10 normal subjects, increasing doses of histamine induced a dose-dependent rise of the nose external temperature. No significant change was observed with the vehicle solution. In six subjects allergic to grass pollen, the nebulization of increasing concentrations of a pollen extract induced a dose-dependent rise in T degree. The T degree rise observed after histamine or allergen corresponded to a marked nasal obstruction. The nebulization of the highest dose of the pollen extract did not induce any T degree rise in six nonallergic subjects. The continuous recording of the skin temperature by a noninvasive method might yield additional information on the vascular changes rapidly occurring during nasal challenges.

Adult↗
PubMed1992

[Eosinophilic gastroenteritis: two case reports].

Eosinophilic gastroenteritis is a rare lesion that may present a diagnostic problem to the surgeon. It may be confused with a malignant tumor because it often presents with intestinal obstruction. We treated two cases at the Hôpital de zone de Morges. In one case the lesion was in the gastric antrum and in the other the ascending colon. Only 27 cases of colonic eosinophilic gastritis are described in the medical literature.

Aged↗
PubMed1991

Image quality index (IQI) for screen-film mammography.

A suitable quantity for evaluating the image quality in mammography is the smallest visible size of an object. This quantity, called the image quality index (IQI), can be derived from the basic image parameters: contrast, MTF, Wiener spectrum. Several evaluation methods of the IQI, all based on statistical decision theory, have been considered. An experimental visibility test using simulated microcalcifications has been performed in order to compare the results obtained with different IQI models. A previous approach, based on simplifying assumptions, yields a good correlation with the visibility test but fails to predict the actual size of the visible objects. Improved models have been derived for an ideal observer and for a 'quasi-ideal' one with perfect or with realistic visual characteristics. The experimental visual results are well modelled by the IQI method, provided that a suitable threshold signal-to-noise ratio is used for each of these models.

Animals↗
PubMed1991

Influence of anode and filter material on image quality and glandular dose for screen-film mammography.

The influence of anode and filter materials on the performance (image quality and dose) of a mammography system is investigated. The image quality is evaluated with the image quality index method. A computer simulation has been developed to calculate the physical parameters of the image quality index (contrast, resolution and noise) as well as the mean glandular dose. The calculations take into account the successive steps of the process: x-ray production, filtration, interaction with the test object, anti-scatter grid, interaction with the image detector (screen-film system). An excellent correlation is obtained between the results predicted by the model and those of experimental measurements, suggesting that the model may be used for the prediction of the performance of mammographic equipment. The experimental conclusions are confirmed: the use of a tungsten anode with a rhodium filter allows a dose reduction without a significant degradation of image quality. The computer program can also be used to simulate the influence of factors which are difficult to combine in practice, e.g., various anode and filter materials, monoenergetic x-rays, etc.

Electrodes↗
PubMed1991

Atypical hyperplasia of the breast: mammographic appearance and histologic correlation.

The mammograms and histologic slides of 58 cases of atypical hyperplasia (AH) of the breast were retrospectively reviewed to determine the geographic correlation (direct, near, or remote) between mammographic abnormalities (if present) and the histologic findings. A direct mammographic-histologic correlation was found in 24 of the 58 cases (41%), near correlation in 15 (26%), and remote correlation in 19 (33%). Clustered microcalcifications were the most common mammographic abnormality that was directly correlated with AH at histologic examination. Atypical ductal hyperplasia was much more frequently associated with a direct mammographic-histologic correlation than was atypical lobular hyperplasia (48% vs 9%). The authors conclude that, although no pathognomonic appearance of AH was discovered, mammographic abnormalities similar to those of small cancers could be directly correlated with histologic findings in 41% of cases. Since AH has been shown to be associated with a five- to tenfold increased risk of subsequent invasive carcinoma, frequent clinical and at least yearly mammographic follow-up is suggested once AH is discovered.

Adult↗
PubMed1989

[Breast cancer before 36 years of age].

Breast cancer in young women is a dreaded disease of bad prognosis, classically worse than for older women. A local study was undertaken in Lausanne to evaluate this notion. 94 cases aged less than 36 years were collected over 15 years, the incidence being 9 new cases per years per 100,000 under-36 women. 76% of the tumors were discovered accidentally by the patient, 24% by a physician during a routine breast examination. Delays from first symptom to histologic diagnosis were short, averaging 19 weeks. 80 mammographies were performed on the 94 cases, of whom 50 positives for a cancer, and 29 negative or doubtful. 22 of these negative 29 were reevaluated, 7 being positive for a tumor and 15 negative, showing either a benign mass or no lesion at all. 6 of the 7 positives were misdiagnosed in easy-to-read breasts, the false interpretation being chiefly caused by the young age of the patients. Pathologically, the rate of invasive ductal carcinoma was very high at 91.4%, which is the highest in the literature, and much higher than for older women in Lausanne (68%). Survival was 84% at two years, 63% at five years and 46% at 10 years, all deaths due to breast cancer. Those rates are better, globally and stage by stage, than for older women or than other reports on young women. We conclude that breast cancer in young women has a better prognosis than formerly thought.

Adult↗
PubMed1988

The potential aggressiveness of sinus osteomas. A report of two cases.

The fronto-ethmoidal osteoma is a relatively rare radiological finding and its growth potential, as well as the complications it may lead to, are often underestimated. Osteomas are a frequent cause of mucoceles and sinusitis due to blockage of the nasal ducts but can also present with more dramatic signs such as orbital or intracranial invasion. This knowledge must draw our attention to the need for follow-up of these tumors, whose growth apparently continues after puberty, especially when they are of the spongy type.

Adult↗
PubMed1988

[Screening for breast cancer].

On the "why", "whom" and "how" of breast screening for carcinoma, the following answers can be provided: Why? As there is no primary prevention, secondary prevention by early diagnosis is the only way to reduce breast cancer mortality. On the other hand, breast cancers discovered by screening can be conservatively treated more often than when they become symptomatic; this is especially important in young patients. For whom? Every woman over the age of 35-40 should be accepted for breast cancer screening. In countries such as Switzerland it is unthinkable to impose screening or even to send personal invitations for screening to the population. Only repeated information through newspapers, TV and conferences will induce women to come for screening. The costs would be paid for by the patient, as medical insurances do not cover this type of preventive medicine. How? Only screening through mammography with or without breast palpation, performed by paramedical personnel, can be considered, because of the cost. It should be done outside the senologic consultation setup for symptomatic patients where a doctor is in charge of the clinical consultation. As Doctor Van der Linde said at the end of his talk at the last Convention of the Swiss Senology Society in Lausanne, pilot projects for breast screening in Switzerland should be started. The Swiss Cancer Society has lately created a commission for early detection of breast cancer to study ways of launching a project.

Adult↗