Biomedical subjects
Publications and source records attributed to B Wimmer.
The cross sectional imaging of ultrasonography and computed tomography provides information for the puncture of focal lesions and fluid collections and additional drainage if necessary. A survey is given of the predispositions, technical aspects, results and complications of both methods.
Between 1985 and 1990 104 operations on the lower thoracic and lumbar spine using the AO-internal spinal fixation system were performed. The preoperative computed tomography (CT) scans as well as either the postoperative CT scans or the CT scans taken after implant removal of 41 cases were available for evaluation of the narrowing of the spinal canal and the subsequent fracture reduction by means of computer-aided planimetry. It is shown that a near normal reduction of the spinal canal through ligamentotaxis is achieved for a fracture between T 12 and L 2, whereas for fractures between L 3 and L 5 an incomplete reduction is observed. A correlation between the neurologic deficit and the degree of narrowing of the spinal canal could not be established. Obviously, the damage to the spinal cord is determined primarily through the dynamic forces of the impact. Also no statistical correlation could be demonstrated in our cases of the time interval between accident and operation to the degree of reduction of the fracture achieved.
A 56-year-old woman showed renal obstruction on the right side. Further examinations revealed a tumor of the renal pelvis. Nephroureterectomy on the right side was done. This extragonadal germ cell neoplasia had an immunohistochemically detected beta-human chorionic gonadotropin (beta-hCG) expression. There were no other primary tumors or metastases. Although there were normal values after the operation, during the postoperative follow-up, the serum beta-hCG temporarily reached 2400 IU/l and then dropped to normal without detection of metastases. No further therapy was given. The patient was alive and well 1 year and 10 months after surgery. To the authors' knowledge, this is the first extragonadal germ cell neoplasia of the renal pelvis with secretion of beta-hCG to the serum.
Cat scanning of the traumatized spine led to an approved classification of different types of lesions. Its application is important--not only for therapeutic reasons but also for the judgement of the end results. The classification enables the definition of a remaining instability (radiological and clinical) and is useful for the evaluation of the prognosis according to the structural changes within the motion segments. The conventional way of appreciating working capacity is no longer satisfying considering the improved diagnostic tools and the increasing frequency of various deformities, instability and even ankylosis and their combinations. As in the evaluation of peripheral joint function a concept is proposed, which is based on the structural changes in the motion segments and their motility. According to the kind and amount of deformity and instability the segment value is multiplicated with factors 1 to 6. The number of involved segments is added to obtain the definite range of working capacity. The concept is practicable in all parts of the vertebral column and allows a differentiated judgement within the usual percentages.
Common manifestations of the von Hippel-Lindau syndrome, an autosomally dominant inherited cancer-prone disorder, include retinal angiomatosis, hemangioblastoma of the central nervous system, renal cysts, renal cancer, pheochromocytoma, and epididymal cystadenoma. Multiple cysts and microcystic (serous) cystadenomas of the pancreas have also been reported occasionally in patients afflicted with this syndrome. In the large Freiburg study of the von Hippel-Lindau syndrome composed of 66 affected individuals, pancreatic lesions were systematically studied. Fifty-five living individuals were examined by abdominal ultrasound imaging. Abnormal findings were confirmed by computed tomographic scan and/or magnetic resonance imaging. For an additional 11 decreased patients autopsy data were available. Cystic lesions of the pancreas were found in 10 patients (15%). One of these patients presented with multiple pancreatic cysts as the only manifestation of the syndrome. In one patient, a malignant islet-cell tumor was found at autopsy. Because multiple pancreatic cysts did not cause major clinical symptoms and because follow-up examinations over an average period of 5 years did not show significant progression of the lesions, it is concluded that these patients usually do not require surgical treatment. Abdominal ultrasound screening is recommended for patients at risk as a tool to identify potential von Hippel-Lindau syndrome gene carriers with pancreatic manifestations. In all patients with multiple pancreatic cysts, the von Hippel-Lindau syndrome should be included in the differential diagnosis.
The preoperative findings of magnetic resonance imaging (MRI) in six histology-proven aneurysmal bone cysts (ABC) are examined and compared with previous publications concerning MRI of ABC. The signal intensities differ considerably, and not all of our cases conform with the literature data. They can be summarised in three different subheadings: one form that is very inhomogeneous in T1- and T2-weighting, with fluid-fluid levels in the cystic spaces; one intermediate form without fluid-fluid levels, which is inhomogeneous only in T2-weighted images; and finally, an unusual form of ABC that has homogeneous low signal both in T1- and T2-weighting, and which has not been described in literature so far.
Interventional radiology has given us new diagnostic and therapeutic possibilities and is no longer a heroic procedure. The best information for the safest approach, except interventions in the vascular system, is provided by the CT scan. If the indications and conditions are respected and the intervention is done with care, it is possible to reach parts of the body, that were only accessible by surgery until now. In therapeutic interventions this also means, that the radiologist will be involved much more in the care of the patients than before.
Computed tomography of the tibotalar and subtaler joints in standardised planes produces comparable images irrespective of examiners. Traumatic, degenerative or neoplastic lesions of the joint surfaces are shown without superimposition. Intraosseous changes can be localised exactly in relation to the joint. Assessment of possible fractures in children is simplified by simultaneous imaging of soft tissues and bone. Diagnosis of traumatic lesions of ligaments or tendons and dislocation of tendons by bone fragments is possible only on CT-images. After injection of air loose intra-articular bodies can be recognised much more satisfactorily with computed tomography than with conventional arthrography.
Computed tomography is an universally applied method of controlling diagnostic puncture of unrecognized processes in practically any region of the human body. The conditions required, the puncture technique, the various pathways and the types of needles used are discussed.
Percutaneous transhepatic access to the bile duct has opened up new possibilities not only for diagnosis by means of cholangiography and cholangioscopy with endoscopically guided biopsy by small-bore equipment, but also for the treatment of benign and malignant obstructive jaundice. In malignant disease recanalization of the obstruction is possible by means of laser, intracavitary irritation, internal bile drainage in Klatskin tumors, large-diameter endoprostheses (e.g., a Y-shaped prosthesis) or metal stents. In benign disease, balloon dilatation of inflammatory stenoses, stone extractions from the bile duct or gallbladder by means of Dormia baskets, ultrasound or piezoelectric shockwave-contact lithotripsy and chemical litholysis are possible. Very often percutaneous access is a real alternative to surgical intervention.
Intraabdominal abscesses are life threatening complications of inflammatory processes or major surgery. Ultrasonography, computed tomography and scintigraphy are the diagnostic methods of choice. Diagnostic percutaneous puncture can be followed by therapeutic percutaneous drainage (PD). The diagnosis "intraabdominal abscess", however, is not sufficient for a rational therapeutic strategy. Therapy of intraabdominal abscesses (IAA) depends upon etiology and localization of the process and the individual situation of the patient.
Thirty seven child mandibular skeletons were analysed radiographically and computer tomographically to establish if there is enough room for osteosynthesis screws. The study demonstrated that in the primary and early mixed dentition there is not enough room in the canine or post-canine region to allow the installation of an osteosynthesis screw without damaging the inferior dental nerve or teeth buds. However, in the later stage of permanent tooth eruption the entire caudal portion of the mandibular body seems to provide sufficient room for osteosynthesis screws. SEM examinations of implant beds of 100 2 mm AO miniscrews inserted into the mandibles of eight fresh cadavers aged eight to twelve years showed cracks, as well as signs of squashing, crushing and shearing stress, regardless of whether the screws were pretapped or not. When, during screw insertion, the axis of the screw deviated by at least 10 degrees from the axis of the tap, two crossing thread courses resulted.
Computed tomography-guided fine-needle biopsies of the pancreas were performed in 54 patients. In 46/54 biopsies, the material obtained permitted a histological diagnosis despite the small external needle diameter of only 0.95 mm. The only complication was due to laceration of an artery of the transverse mesocolon. The prevalence of malignant tumors was 67%. Adenocarcinoma was diagnosed in more than 80% of all biopsies; rare findings were malignant carcinoid or centroblastic lymphoma. Benign tumors included mucinous adenocystoma and serous microcystic adenoma. Within the group of patients where pathologic-anatomic evaluation was possible, the sensitivity of fine-needle biopsy for malignant tumors was 87% and the specificity 100%. A positive needle biopsy diagnosis for a malignant tumor reduces the number of exploratory laparotomies needed and is helpful in the planning of surgery.
CT is a diagnostic tool that allows imaging of the wrist, wrist joint and distal radioulnar joint in the axial plane without superimposition. The differentiation of bone, joint space and soft tissue is possible in a single examination. This is helpful in the diagnosis of traumatic, degenerative or malignant lesions of bones together with the soft tissue reactions. Further information can be obtained by means of three-dimensional reconstructions.
Assessment of intraarticular loose bodies in the elbow joint with CT arthrography is more successful than with conventional arthrography. Calcification in the capsule is better delineated by CT. The diagnosis of osteochondrosis dissecans can mostly be established by plane ray and conventional tomography.
To estimate subchondral mineralisation patterns which represent the long-term loading history of individual joints, a method has been developed employing computed tomography (CT) which permits repeated examination of living joints. The method was tested on 5 knee, 3 sacroiliac, 3 ankle and 5 shoulder joints and then investigated with X-ray densitometry. A CT absorptiometric presentation and maps of the area distribution of the subchondral bone density areas were derived using an image analyser. Comparison of the results from both X-ray densitometry and CT-absorptiometry revealed almost identical pictures of distribution of the subchondral bone density. The method may be used to examine subchondral mineralisation as a measure of the mechanical adaptability of joints in the living subject.
In a prospective study in 49 patients with rectal carcinoma the correlation of pre- and post-operative staging by CT and endorectal ultrasound (EU) was compared according to TNM-classification. With CT the pre/postoperative results correlated in T1 in 9/10, in T2 in 10/16, in T3 in 13/15 and in T4 in 6/8 patients. By EU identical results were found in all T1, in 10/12 T2, in 17/20 T3 and in 6/7 T4 stages. Overall, pre- and postoperative identical results were found by CT in 38 and by EU in 43/49 patients. Overestimation of the tumor stage was similar with both methods: 5 by CT and 4 by EU. Underestimation of the stage was more often by CT in 5 than by EU in 2 cases. (CT: accuracy 77.5%, sensitivity 88.3%, specificity 94.4%; ES: accuracy 87.7% sensitivity 91.5%, specificity 97.8%). Criteria for interpretation are discussed. In early tumor stages the depth of tumor invasion can be better evaluated by EU. In late stages both methods give important information for surgical strategy.
Fifty consecutive patients with acute pancreatitis were assessed with respect to a biliary origin of the disease. Endoscopic retrograde cholangiopancreaticography, surgery, and autopsy were used to define biliary pancreatitis. Ultrasound, computed tomography, and several laboratory tests (SGOT, SGPT, alkaline phosphatase, and bilirubin) were analyzed for their ability to detect a biliary origin of the disease. Ultrasound and computed tomography could not reliably make the diagnosis in the 10 patients found to have biliary disease. Receiver-operator-characteristic curves revealed that none of the laboratory tests assessed had sufficient sensitivity and specificity to determine the diagnosis, although all tests showed higher mean values in biliary pancreatitis. SGPT gave the best discrimination (positive predictive value 53%, negative predictive value 94%, cut off 40 units/liter). Therefore, initial ERCP is suggested for a reliable diagnosis of biliary origin of acute pancreatitis.