MR in the diagnosis of bone tumours

Forty-two patients with benign as well as malignant bone tumours or with tumour-like lesions of bone were evaluated using MR tomography. The appropriate choice of examination parameters is an essential prerequisite for the adequate visualisation and the definitive verification of the presence of a tumour. By means of its multi-planar display, MR provides definite advantages in the determination of tumour localisation and extension as well as in differentiating intra-tumoural haemorrhage from surrounding, non-involved tissue. In addition, the clear delineation of neighbouring structures such as muscular compartments and blood vessels achieved in MR can be useful in the planning of an eventual surgical approach. This new technique has proved itself superior to other available imaging modalities in the differentiation of residual or recurrent tumour from post-operative changes. A characterisation of the nature or histology of a suspicious lesion on the basis of relaxation-times or signal intensities, however, is not yet possible.

[Diagnosis of bone necrosis by magnetic resonance tomography. The potentials for early diagnosis]

Twenty-eight patients with necrosis in the hip joint, the femoral condyles and the talus were examined by MR tomography. This revealed various features whose frequency depended upon the various stages of the necrosis. Three patients who showed no, or only indefinite, changes on radiographs, displayed clear evidence of necrosis on MR. Staging of femoral head necrosis on the basis of MR criteria is suggested, as well as a suitable procedure for early diagnosis. Accurate localisation and knowledge of the extent of the necrosis by means of MR makes it possible to plan an osteotomy accurately.

[MR measurements on a perfused renal artery model with pulsatile flow]

MR tomography permits visual demonstration of flow and turbulence. A model was used to compare MR-measured signal intensities and flow profiles as obtained by Doppler anemometry.

Magnetic resonance (MR) in the diagnosis of pancreatic disease

New methods of examination are measured in terms of the efficiency of their predecessors. The introduction of endoscopic retrograde cholangiopancreatography (ERCP) and computerised tomography (CT) constituted a turning point in the diagnosis of pancreatic disease. In its incipient stages as a clinical diagnostic method, the question is raised whether or not there is evidence that magnetic resonance (MR) can supplement, improve upon or replace the customary methods. It must, however, be taken into account that the technical development of MR is still in progress and that clinical experience with MR in the diagnosis of pancreatic disease, as in other areas, is still insufficient. At this point it is only possible to survey the trends.

MR-tomography in the diagnosis of malignant soft-tissue tumours

Nine patients with malignant, peripheral soft-tissue tumours were examined using a 0.35 T MR equipment. In 7 cases in which tumour presence was surgically verified, a definite identification as well as an exact determination of tumour extension was achieved using MR. The various tumours exhibited a particularly high degree of contrast when using a T2-weighted Spin-Echo-(SE) as well as the T1-weighted Inversion-Recovery-(IR) mode. The T1- and T2-relaxation times of the soft-tissue malignancies evaluated in this study were markedly longer than those obtained for normal tissue. In 2 patients within the collective, a definite exclusion of tumour recurrence was possible.

[The joints in the posterior part of the foot in the computed tomogram. Studies on amputation preparations and clinical observations]

CT of the foot often helps clarification of difficult problems where conventional radiology has proved inadequate. Sections in the coronary and transverse plane may demonstrate fractures, joint involvement and displacement of bone fragments. Ill-defined degenerative changes in the talo-calcaneal joint can be demonstrated. The extent and localisation of rare tumours of the foot can be shown and additional information may be obtained by densitometric studies.

[Computer tomography of sports injuries]

Computed tomography (CT) provides axial slices plane and shows excellent details of bones and different soft tissues, favoring its use in traumatic lesions caused by sporting activities. Complex anatomical structures such as the shoulder, the vertebral column, the pelvis, the knee, the tarsal and carpal bones are often better recognized in detail than by conventional radiography. Fracture lines, localization of bone fragments and involvement of soft tissues are clearly demonstrated. Luxations and bone changes leading to luxations can be shown. CT arthrography provides for the first time a direct visualization of joint cartilage and of cruciate ligaments in the knee joint, so traumatic lesions such as chondropathia patellae or rupture of the cruciate ligaments are shown with a high degree of reliability.

[Clinicoradiologic significance of different study parameters in NMR tomography of the abdomen]

One hundred and nine patients have been examined with NMR tomography, including 44 examinations of the abdomen. In 35 cases, different sequences were used. In 28 patients it was possible to determine the relaxation times T1 and T2. Pathological processes showed not only different T1 and T2 values, but also different pictorial contrast. In order to extract the maximum amount of information, it is necessary to carry out NMR tomography with varying sequences.

[Experience with NMR tomography of the skeletal system]

The value of nuclear magnetic resonance (NMR) tomography in the skeleton is analysed in 27 patients who had been examined by a prototype NMR scanner (resistive magnet, 0.2 Tesla). Anatomical structures and detail can be seen using the spin-echo mode and brief sequences. There is marked contrast difference between normal and abnormal tissues. Pathological changes lead to marked alterations in relaxation times. Inflammatory conditions, tumours and aseptic bone necrosis are demonstrated with a high degree of sensitivity. Tomography in the three geometric planes, with any desired additional plane, shows the extent and localisation of bone abnormalities.

Biliary drainage by teflon endoprosthesis in obstructive jaundice--experiences in 69 patients treated by PTCD or ERCD

In 69 patients with extrahepatic biliary obstruction a specially designed teflon tube, the endoprosthesis, was inserted across the ductal stenosis either by percutaneous or by endoscopic route to reduce jaundice. After gaining experience our success rate of stent placement was more than 90%. Compared with catheter drainage the endoprosthesis worked faster and more efficiently, while in palliative treatment the quality of life of the patient improved and secondary cholangitis was prevented. The rate of significant long-term stent obstruction can be tolerated in view of the expected life span of four months as average in our material.

The diagnostic value of morphology and relaxation times in NMR-imaging of the body

NMR examinations were performed on a total of 109 patients using a resistive magnet. In 67 patients various organs and tissues of the face and neck the trunk and the limbs were evaluated in axial, sagittal and coronal planes. The use of more than one sequence time is essential for adequate representation of the anatomical structures and for detection and evaluation of pathological processes. They are the base to compute "secondary" T1- and T2-images, in order to obtain numerical values of both relaxation times. Thus a better understanding of the morphology of structures within the images is obtained. NMR appears to represent a sensitive method of tissue characterization: Specific changes in the T1- and the T2-pattern were found in pathological conditions, e.g. longer T1-times with normal or moderately longer T2-times in tumors compared to healthy tissue and extremely long T1- and T2-times typical of fluid accumulations.

[Head and neck cancers. What's new in clinical oncology for the practicing ENT physician?]

An interdisciplinary evaluation is made of the most common forms of head and neck cancer, with emphasis on certain aspects.--In the field of x-ray diagnostics, computed tomography dominates varying importance being given to the individual organs. Nuclear medicine pays particular attention to skeletal scintigraphy and gallium scintigraphy. In radiation therapy, progress has been made especially through the use of optimal radiation planning as well as the use of the after-loading technique and neutron radiation. Antineoplastic chemotherapy is currently being used as palliative treatment, adjuvant chemotherapy and as the first step towards a curative therapy.

[Therapeutic embolization by angiographic catheter (author's transl)]

Vascular occlusion can be performed by remote-controlled, fluoroscopically guided angiographic catheters and selective injection of occlusive material. Inoperable tumors, acute bleeding, organ devitalization, and vascular malformations can be indications for this method. In difficult operation sites, this could be the preferred as definitive treatment. As a preoperative procedure, it can help control intraoperative hemostasis and thus shorten the operation time. During the last few years the most frequent indications in our department were acute bleeding and vascular malformations.

Evaluation of the cruciate ligaments by CT

Delineation of the cruciate ligaments in 112 patients using the computed tomography under arthrographic conditions was reported. Special position were used allowing for the demonstration of both cruciate ligaments in their complete lengths. In 6.2% of the examinations a reliable demonstration of the cruciates was not possible for technical reasons. Demonstration of normal cruciate ligaments in CT arthrography was described and normal values were tabulated. Recent cruciate ligament injuries were seldom examined by CT arthrography since the clinical symptoms were mostly unequivocal. The old ruptures of the ACL were divided into 4 different types: Type I: Rupture of the femoral origin that adjoins the PCL. Type II: Attenuation of the intraligamentary ruptured ligament with a preservation of origin and insertion. Type III: Complete rupture with shrinking and retraction of the fragments. Type IV: Osseous involvement of the femoral origin or tibial insertion. In 36 old cruciate ligament ruptures, the sensitivity of this method of investigation was 97%, the specificity 100%. After reconstructive surgery, CT arthrography allows for an objective analysis of the operative results and permits the comparison of different techniques of surgical repair.

Percutaneous biopsy of retroperitoneal lymph nodes. A multicentric study

Percutaneous transperitoneal biopsy of retroperitoneal lymph nodes is a fast and well tolerated procedure to improve the diagnosis of metastasis for staging primary tumours and general lymphatic disease. In 303 patients examined by lymphography and biopsy, cytology disclosed metastases in almost twice as many patients as lymphography alone. By combining both examinations, staging operations can be omitted in many patients.

[Percutaneously introduced bile duct prostheses as primary measure in obstructive jaundice (author's transl)]

The simplest measure for overcoming obstructive jaundice, and the one with the least complications, is percutaneous transhepatic bile duct drainage, which we have carried out on 38 patients. We have abandoned the catheter technique with combined external and internal drainage and instead use primary implantation of a bile duct prosthesis by the transhepatic route in cases of obstructive jaundice. The results are better, and the procedure is easier for the patient. Our experience with twelve implants in nine patients is described.

[CT for staging of systemic lymphatic diseases (author's transl)]

In 75 patients with lymphoma (46 Hodgkin's disease, 29 non-Hodgkin lymphomas) computed tomography was performed in order to detect neoplastic invasion of the abdominal organs (55 new cases) or to control the results of treatment (20 cases). In 30 cases enlarged retroperitoneal or mesenteric lymphnodes and/or liver or spleen enlargement were found. Neoplastic involvement of lymphnodes without enlargement was missed in two cases. CT failed also to demonstrate microscopic malignant invasion of liver and spleen. The false-negative rate in our series was 10.9%. Computed tomography is a non-invasive method which is very well suited for staging malignant lymphoma.

[CT and lymphography correlations in the evaluation of patients with testicular tumours (author's transl)]

27 patients with testicular tumours were examined by lymphography and computerized tomography for evaluation of metastatic spread in the retroperitoneal lymphnodes. A good correlation of results was found in 23 patients. In 4 cases lymphography failed to show metastatic disease, which was easily recognized by CT. In account of the lymphatic spread pathways of testicular tumours leading mainly to the lymphnodes close to the kidney pedicle CT appears to be method of choice in the staging of these patients, as the lymphnodes in this area are often not demonstrated by lymphography. Computerized tomography allows the exact localisation and extension of neoplastic lymphnodes and at the same time a good evaluation of the surrounding organs.