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Multiformat imagers based on laser systems are used for documentation in an increasing number of investigations. The specific problems of quality control are explained and the persistence of film processing in these imager systems of different configuration with (Machine 1: 3M-Laser-Imager-Plus M952 with connected 3M Film-Processor, 3M-Film IRB, X-Rax Chemical Mixer 3M-XPM, 3M-Developer and Fixer) or without (Machine 2: 3M-Laser-Imager-Plus M952 with separate DuPont-Cronex Film-processor, Kodak IR-Film, Kodak Automixer, Kodak-Developer and Fixer) connected film processing unit are investigated. In our checking based on DIN 6868 and ONORM S 5240 we found persistence of film processing in the equipment with directly adapted film processing unit according to DIN and ONORM. The checking of film persistence as demanded by DIN 6868 in these equipment could therefore be performed in longer periods. Systems with conventional darkroom processing comparatively show plain increased fluctuation, and hence the demanded daily control is essential to guarantee appropriate reaction and constant quality of documentation.

Thirty-eight patients with mediastinal and/or hilar masses were imaged by computed tomography (CT) and magnetic resonance imaging (MRI). Results were analyzed retrospectively regarding the ability to demonstrate the masses, their number, size, definition, location and tissue characteristics. CT and MRI showed equivalent results in 32 cases; additional information was obtained in two patients by CT, in four patients by MRI. In view of the specific advantages and limitations of both CT and MRI we believed that in patients with mediastinal and/or hilar masses, contrast enhanced CT remains the procedure of choice after performing plain chest radiographs; in certain cases MRI will prove useful for further evaluation.

Fifty CT examinations of 31 patients with testicular tumours were evaluated. In 13 patients, the CT findings were compared with results of histological-surgical or autoptic findings. Comparative evaluation of CT, lymphography and other methods of diagnosis is demonstrated. The high incidence (80 %) of correct CT results is emphasised, in staging patients and in the work up of patients with long treatment time and history of tumor recurrence. The advantages of CT are: 1) possibility of exact localisation and determination of tumor-size, as well as discovery and assessment of their patho-anatomic relations to the adjacent organs, 2) utilisation of these data in the planning of radiotherapy, 3) the possibility to document exactly any treatment sucess (reduction of tumor size). In more than 30 % of the patients, CT scanning revealed, despite radiological preliminary examinations, clinically and radiologically unexpected pathologic findings, such as osseous metastases (17%), non functioning kidneys, metastases in the liver and pleura.

Due to the important improvement represented by the latest computed tomography (CT) technology in respect of detail and excellent contrast resolution normal and pathological structures of the inner and middle ear can be visualised. The clinical and diagnostic value of CT in comparison to standard x-rays and tomography is prospectively evaluated on the basis 74 patient examinations. Today CT is unsurpassed in the diagnosis of cholesteatomas and glomus tumours and ranks first among all imaging modalities. Chronic inflammatory diseases and deformities of the middle ear can be evaluated in most cases on the basis of standard x-rays and tomography. The importance of CT is primarily complementary, except in preoperative cases. Fractures should be visualised first via standard x-rays. In cases of questionable complications (e.g. tympanic or intracranial haematomas), CT should be the next step. Conventional tomograms are not necessary.

In 12-15% of rectal carcinomas a relapse appears during the first two years. Until now, early radiological diagnosis by means of conventional methods was extremely difficult and subject to high and negative error rates. Computerized tomography--in comparison to conventional radiological methods--allows early recognition of these tumour relapses and finds excellent use for purposes of radiological post-operative management.

For the detection and classification of dissection of the thoracic aorta, in cases where a corresponding tentative diagnosis is made on the basis of clinical and plain thorax radiographs with intravenous contrast medium, computed tomography is the method of choice. In cases in which, primarily, a Type A dissection is suspected, catheter angiography is to be preferred to CT, in spite of being the more invasive method, because it is the only method capable of supplying the information necessary for surgery. In all other cases of dissection of the thoracic aorta computed tomography has the highest clinical-diagnostic value. It furnishes an initial finding on the basis of which the course may be monitored without difficulty where there is a corresponding clinical indication. It is as yet impossible to judge how far routine magnetic resonance imaging will supplant or complement CT in making the initial clinical diagnosis.

A scrutiny of the palette of possibilities in the radiological examination for the discovery and identification of neurinomas of the auditory nerve, shows that, apart from plain roentgenography, which continues to occupy the first rank after clinical examination, computer tomography represents the most important contribution towards identifying tumors of the cerebellopontine angle. For the identification of neurinomas (of the Brunner type) of the medial type this method of examination is the method of choice. We are not so confident with regard to the small lateral neurinomas which are situated within the auditory meatus. We consider that the discovery of these extremely small lateral neurinomas of the auditory nerve remains extremely difficult and is mainly left to positive cisternography. Probably, the discovery of these neurinomas remains one of the happy chances of early radiological diagnosis. Nevertheless, the knowledge acquired during the past few years must be considered an essential step forward in radiodiagnostics, and hence represents a great aid in the curative treatment of the patient.

With the rapid increase in the number of intensive care units in surgical and medical departments knowledge of early radiologic signs of pulmonary edema gains in importance. On the basis of investigations by American authors typical changes in the distribution of pulmonary blood supply can be shown, in good correlation with pressure changes in the pulmonary vein in left heart failure. When pressure rises in the pulmonary vein the well-know changes of interstitial or alveolar (acinary) pulmonary edema arise. Differential diagnosis between pulmonary edema due to left heart failure and edema from other causes is aided on the one hand by the presence of interstitial pulmonary edema and redistribution of blood, on the other hand by the abnormaly large heart and configuration. Neither Röntgen appearances nor type of distribution of pulmonary edema are specific for any given cause. In all cases of pulmonary edema, the primary-peripheral excepted, clinical signs either occur later than X ray findings or will be absent altogether. Respiratory physiology permits, according to the severity of the edema, proof of hypoxemia with pronounced differences in the regional ventilation-perfusion quotient up to marked reduction of compliance and increase of resistance.

Two cases with the diagnosis of asymptomatic chylopericard were evaluated. One was a 20-year old girl who had been operated on for intrathoracic lymphangioma and chylopericardium that existed since birth, and who developed a chylothorax after the operation. The second case report concerns a 22-year old man who had been suffering from a posttraumatic asymptomatic chylopericardium for two years and who is being treated conservatively "Low-fat diet").

Tracheal cross-sections can be measured by means of computerised tomography with hitherto unparalleled accuracy. Among the patients examined by the authors (43) women following tracheopexy because of tracheomalacia), computerised tomography yielded approximately 3 times as many pathological findings as was possible by conventional x-ray diagnosis. Over and above this, it is always possible to calculate the flow resistance, a fact which can be of great importance for therapy planning and control. Hence, in all cases where accurate visualisation of the tracheal cross-section is necessary, computerised tomography appears to be the method of choice at the present time.

A CT control scan of 32 patients after transsphenoidal resection of a pituitary tumour revealed sellar contents of different density and varying extent. Additional criteria were used to differentiate the intrasellar structures (size, extent, shape, structure, contrast enhancement, bone changes). CT made the definite diagnosis in 6 patients with pituitary tumour recurrence. Hormonal measurements were superior to CT in identifying recurrent tumours in another 3 patients. It is concluded that hormonal methods should be used in evaluating patients after surgery of a hormone-producing tumour. However, CT is the most useful method in detecting tumour recurrence in patients with non-functioning adenomas, and, if an adequate technique is used (coronal scanning, iv-contrast), even clinical asymptomatic tumours can be identified.

The results of computed tomography of 48 patients after operation on rectal carcinoma who underwent close-meshed computer tomographic examinations are given in a prospective study. (First examination 6 weeks after operation, further examinations at intervals of 3 months, mean observation time: 12 months). The results of follow-up by means of computer tomographic examination are compared with clinical examinations and control of CEA levels. The use of computer tomographic examination resulted in 43 confirmed negative, 3 confirmed positive and 2 false negative findings (including cases with CT-aided fine needle biopsy). These results give an accuracy of 96% and thus exceed clinical examination and controls of CEA-level. How far early diagnosis of local recurrence of rectal cancer influences survival time, can be answered after completion of this study in the next few years.

On the basis of examinations carried out in 27 patients (26 histologically verified carcinomas of the bladder), it is shown that computerised tomography considerably improved the preoperative classification, into stages, of the bladder tumours coming up for surgery. Endovesical growth cannot be differentiated with certainty. Perivesical expansion of tumours and the identification of lymphatic node metastasis can be covered significantly better by computerised tomography than by other methods.

Fibrosing mediastinitis is a rare entity either idiopathic or caused by granulomatous disease. Plain film findings mainly show widening of the upper half of the anterior mediastinum, whereas CT delineates more clearly the exact location of the mediastinal mass and the extent of compromise of mediastinal structures. Although vessels surrounded by the fibrous mass are typically smoothly bordered and only rarely displaced, diagnosis can only be suspected together with the patients history and clinical course.

Magnetic resonance tomography was performed on 158 patients with different indications before and after the administration of contrast medium. The MR examination included various plain T1 and T2 weighted spin echo sequences as well as T1 weighted examinations after intravenous application of Gadolinium-DTPA ("Magnevist", Schering AG) in a dosage of 0.1 mmol/kg body weight. The following conclusions were drawn: The sensitivity of MR in detecting brain tumors, acoustic neuromas and pituitary adenomas was improved considerably after the administration of "Magnevist". To diagnose the type of tumor, the criteria which apply to Gd-DTPA are similar to those used for iodine-containing contrast medium in CT. In about 2/3rds of the cases, delineation of pathological tissues from surrounding edema and normal structures was better than in plain films. Hence, accurate, pretherapeutic staging of bronchial carcinomas and an exact definition of the expansion of the malignancies in the muscle-skeleton system were possible. In respect of tumors in the region of the base of the skull, we could omit T2-weighted sequences without noticeable loss of diagnostically relevant information; the examination time could thus be shortened by about 12 minutes.

The diagnostic capacity of abdominal CT as a follow-up in ovarian cancer is demonstrated on 67 patients verified by a second-look operation. In the diagnosis of recurrence CT has a sensitivity of 83%, a specificity of 94% and an overall accuracy of 88%. With local recurrence or residual tumours CT has an accuracy of 91%, with liver metastases of 94%. The accuracy in finding peritoneal carcinosis is 84%. Ascites proved to be a sure sign of peritoneal carcinosis. Because of its high sensitivity second-look operation can be avoided in case of a positive report. In a negative report a second-look operation will be necessary to verify the success of therapy. In the follow-up of ovarian cancer CT should be performed every 6 month during the first 2 years and yearly for another 3 years.