Digitale Bilddiagnostik最新文献

Abuse of ergotamine can release a generalised brain edema and brain infarctions. This can be visualized by CT, MR and angiography. The reason, however, can only be found in the patients history.

25 patients with an extrathoracic malignant tumor and radiologically proven lung nodules had a thoracic CT preoperatively. 111 nodules were confirmed by surgery (median: 10 mm). Histopathological examination revealed 104 metastases or sterilised metastases and 7 benign nodules. CT detected 97% of the nodules. Localisation of the nodules according to different lobes or segments was correct in 97% of nodules. CT is a very sufficient method for the detection and localisation of lung metastases.

A case of primary spinal echinococcus with bone destruction is presented and the findings in CT and MR imaging are discussed. Although CT and MRI are complementary studies for the diagnosis of the spinal echinococcosis, MRI is the study of choice for prolonged follow-up of complicated cases.

Digital image intensifier radiography (Siemens/Polytron) offers the chance to reduce patient exposure dose in hysterosalpingography (HSG) by 85% compared with conventional film/screen radiography and by 11% compared with the 100 mm technique. By appropriate choice of the parameters the signal-to-noise ratio was adapted to the detectability of the diagnostic information (variation of the dose). Thirty patients were examined with the 28 cm image intensifier and an image intensifier input dose of 50 microR. The diagnostic image quality was assessed being aware of the results of laparoscopy or surgery; in 29 cases the quality was classified very good without any limitations. Digital image intensifier radiography offers additional advantages over conventional x-ray units: the images are directly available on the monitor and offer the possibility of post-processing.

In a prospective study, 150 threedimensional reconstructions of patients with bone diseases were analyzed. It could be seen that 3 D images were relevant for therapeutic considerations in diseases of craniofacial bones, and to a lesser degree for other skeletal regions. In no case was the 3 D reconstruction the only important factor for the therapeutic decision. The study demonstrated that 3 D imaging of the pelvic bones, especially for necroses of the femoral head, is severely limited without the possibility of computer-aided disarticulation.

Whereas generalised neurofibromatosis is a relatively frequent disease its combined occurrence in conjunction with agenesia of the corpus callosum is extremely rare and probably a casual coincidence.

Pathological lesions of the parotid gland were examined comparatively with different examination sequences both plain and with the contrast medium Gd-DTPA. There were 36 benign lesions (parotitis, Sjögren's syndrome, adenoma, etc.) and 24 malignant tumours (squamous cell carcinoma, adenocarcinoma, adenoid cystic carcinoma etc.) Examinations were carried out at 1.0 T with long and short spin echo sequences in transverse and frontal layer orientation before and after application of Gd-DTPA as contrast medium. In the patients suffering from parotitis the best results were obtained with plain T1 and T2 sequences; the contrast medium Gd-DTPA remained without superior diagnostic relevance. However, in Sjögren's syndrome (myoepithelial sialadenitis) administration of the contrast medium always yielded a characteristic honeycomblike pattern. In benign and malignant space-occupying growths MRI supplied additional diagnostic information with Gd-DTPA in respect of defining the tumour borderlines and paths of infiltration. MRI is now a significant diagnostic tool in inflammatory and tumorous lesions of the parotid gland.

A flow model was used to study the appearance of poststenotic flow on spin-echo (SE) and fast-field-echo (FFE) images. On SE-images, extensive signal void distal to the stenosis was observed even with low flow velocities. FFE-sequences with short echo time and flow-compensated gradients demonstrated poststenotic loss of signal intensity only with high flow velocities. On FFE-images, the poststenotic signal loss increased with the severity of the stenosis, if total flow across the stenosis was maintained. The lower limit of the mean flow velocity within the stenosis, for which signal void was observed, appeared essentially independent of the degree of the stenosis. The results demonstrate the capability of flow-compensated FFE-sequences to assess poststenotic turbulent flow.

29 patients with unclear symptoms in the right lower abdomen received a CT-examination in an attempt to prove or exclude appendicitis. In almost all cases it was possible to demonstrate the inflammatory process in the appendix itself (size of the organ). More diagnostic information was obtained by careful examination of the accompanying reactions of the cecum, the mesenteriolum, the fascia and other neighboring organs. Thus CT is a valuable tool in the diagnosis of appendicitis and facilitates the decision for or against an appendectomy, which otherwise may be very difficult.

Ultrasound waves spread in the body in changing the acoustic pressure in a high frequency causing heat production or acoustic cavitation. There are many adverse effects known in cell cultures or in animals. Epidemiologic studies showed no evidence at the present time that ultrasound causes any biological effects in human subjects. Therefore further observations, especially of new applications are necessary.