Anders Hemmingsson

Xeroradiography and Conventional Radiography in Examination of the Larynx

Comparison of the visibility and radiation dose at xeroradiography and ordinary conventional radiography have been made in experimental and clinical examinations of the larynx. The investigation indicates that xeroradiography cannot replace positive contrast examination and gives a considerably higher radiation dose than conventional radiography.

The Cochlear Aqueduct

Histologic examinations of the cochlear aqueduct were performed some decades ago by KARLEFORS (1924), MEURMAN (1930) and KARBOWSKI (1930), among others, and more recently by WALTNER (1947, 1948), ANSON et coll. (1964,1965), RITTER & LAWRENCE (1965), HENNEFORD & LINDSAY (1968), PALVA & DAMMERT (1969) and PALVA (1970). Opinions differ as to whether or not the aqueduct is open and allows free passage of cerebrospinal fluid from the subarachnoid space to the scala tympani. PALVA & DAMMERT, however, concluded that fluid exchange through the cochlear aqueduct was fully feasible, but stated that its course and structure are not sufficiently known, for instance in cases of Menieres disease. According to DORPH et coll. (1973), an unusually wide aqueduct may be a possible cause of fistulas following stapedectomies. The present investigation was therefore undertaken to determine whether the cochlear aqueduct can be demonstrated at roentgen examinations of temporal bone specimens as well as of living subjects. To our knowledge, the roentgenologic appearance of the whole cochlear aqueduct has not been described previously.

Soft Tissue Intensification in Frontal Roentgenography of the Larynx

The perception of roentgenographic detail is not completely understood but may well be dependent upon the radiation absorption gradient over the contour of a projected structure (WALLS 1954) and its inference by other structures (TUDDENHAM 1957, EDHOLM 1960). The visibility of the soft tissue structure is disturbed and limited by the spongy bone of the cervical vertebrae in frontal roentgenography of the larynx. Structures of low contrast are thus masked by the closely spaced structures of fairly high contrast. Laryngography is the best method of improving the visibility of laryngeal soft tissue (POWERS et coll, 1957, THORNBURY & LATOURETTE 1967, BRINDLE 1966, LANDMAN 1970, HEMMINGSSON 1972, and others). This technique necessitates premedication and anaesthesia with the contrast media used at present; other techniques with a similar diagnostic accuracy but without this disadvantage are therefore desirable.

Roentgenologic examination of the larynx. A clinical comparison.

The methods of treatment of malignant laryngeal lesions have changed considerably during the last two decades. Partial laryngectomy, which means that laryngeal function is to some extent preserved, is thus performed nowadays as hemilaryngectomy in the case of neoplasm limited to the vocal cords, and as subtotal supraglottic laryngectomy in supraglottic tumours not involving the cord. The frequency of recurrence and the survival time are the same for these operations as for total laryngectomy (PEREZ et colI. 1968, OGURA & BILLER 1969). Good results are also obtained from radiation therapy in, for example, growths confined to the vocal cords. The exact localization and extent of the laryngeal lesion should be determined so that the best therapeutic method may be chosen. If radiation therapy is to be given, the location and size of the treatment field must be selected with precision. This evaluation cannot be made solely clinically, including direct laryngoscopy; this may result in erroneous classification of the tumour before operation in approximately 20 per cent of cases (OGURA et colI. 1960 and LANDMAN 1970). It is mainly the caudal extent of the lesion that is difficult to evaluate in vocal cord and subglottic tumours. Subglottic dissemination thus escaped detection at laryngoscopy in about 80 per cent of cases in a series reported by MARTENSSON (1967), and at laryngoscopy combined with tomography which

Roentgenologic methods in examination of the larynx : Comparative phantom investigations in the frontal projections

Roentgenologic methods in examination of the larynx : Comparative phantom investigations in the frontal projections

Perception of Simulated Lesions in the Lung

The detectability of phi 20 mm, disk-shaped objects on a normal chest film was investigated at viewing distances of 0.3, 1.0 and 3.0 m. Objects with a tapered border were found to be best perceived at longer distances. The photpgraphic density difference between object and background yielding a 50% detection probability was found to increase from 0.025 to 0.060 when the outer gradient zone of the object increased from 0.8 to 4.0 mm.

Roentgenologic Examination of Tracheal Stenosis

Conventional roentgenography, tomography and tracheography were compared for evaluation of tracheal stenosis in phantom experiments and in 55 patients. It was found that the stenosis, as well as the relative position of a tube inserted for dilatation, is best evaluated by tracheography. If this method cannot be used, conventional roentenography with a high tube potential gives a better result than tomography.

Image enhancement by digital-analog filtration. II. Tests of filters.

The function of a device for frequency filtration of roentgenograms with digital filters has been tested with the use of different filters. The image was altered in the expected way, which means that the device is suitable for investigating the possibilities of different filters to improve the diagnostic ability. The results of the tests indicate that improvement should be achieved by low-pass filtration.

Image enhancement by digital-analog filtration. III. Experiences with bone metastases.

The conventional roentgenogram is rich in detail and sometimes the large amount of information presented may render the evaluation difficult. This is true, for example, in the diagnosis of bone metastases, where disturbing structures of spongy bone are superimposed upon the metastasis and reduce its perceptibility. Reduced reproduction of the bone trabeculae with remaining contour and contrast of the metastases is therefore desirable. This should be possible to achieve by frequency filtration as spongy bone has higher spatial frequencies than round soft tissue structures (ROSSMANN 1968, KUNDEL et coll. 1969, 1972, ROSSMANN & MOSELEY 1969, ZISKIN et colI. 1971, ROCKOFF 1972, HEMMINGSSON et coll. 1972). In the present report the result of frequency filtration of films with overlooked bone metastases is described.

Book Review: Biomedical Magnetic ResonanceBiomedical magnetic resonance. Edited by JamesThomas L. and MargulisAlexander R.. Radiology Research and Education Foundation, San Francisco; Blackwell Scientific Publications, Oxford1985. Price: GBP 92

included in all cases and a short reference list is available directly after several cases. Most scans, in the chapter of gynecology, are made with static ultrasound equipment and are of a rather good, but not excellent quality. The following chapters of obstetrics and the breast have a similar design, and the only complaint is that the image quality. especially in the part of normal fetal anatomy, is not compatible with what is possible to obtain with modern ultrasound equipment. The chapter of the neonatal head is still more suffering from the inferior image quality, but is otherwise well written. with the cases selected to show the most common lesions and malformations. An atlas should be easy to read and mainly focused on the illustrations. This book is no exception from that rule. In summary this atlas gives the reader a glimpse of a large variety of normal and abnormal findings in the pregnant and nonpregnant woman and her child. The text is concise, clearly written, and easily read. The major drawback is the poor image quality which suffers when compared with state-of-the-art realtime scanners. Torbjorn Andersson