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Biomedical subjects

W Weidenmaier

Publications and source records attributed to W Weidenmaier.

At least 19 recordsLinked to original sources
PubMed1995

[MR functional diagnosis of the cervical spine after strain injury].

50 patients with a history of distortion injury of the cervical spine were examined with static and functional MRI. Functional MRI consisted of different patient's positions from maximal extension to maximal flexion (30 degrees, 0 degrees, 25 degrees, 40 degrees, 50 degrees). T2*-weighted gradient echo sequences were performed in a sagittal view for the different positions. Ligamentous instabilities and disc protrusions were seen only in functional MRI in 17 patients. These findings correlated with the neurological symptoms. Two patients were treated by operative fusion because of these findings.

Adult↗
PubMed1992

[MR angiography of occlusive changes in the superior thoracic inlet veins].

We used MR angiography to assess the thoracic inlet veins in 5 normal volunteers and 14 patients with thrombosis of these veins. The results were compared with conventional venography and contrast-enhanced computed tomography (CT). The normal anatomy was readily depicted by MR angiography in all normal volunteers. Pathology was assessed correctly by MR angiography in all patients. Thrombosis of the internal jugular vein was seen on MR angiography in all cases whereas conventional venography failed to demonstrate this region adequately in 3 cases. The best overview of the thoracic inlet veins was achieved in the coronal plane; however, for detailed demonstration of pathology, imaging in additional planes was necessary. We conclude that MR angiography is a promising method for non-invasive assessment of thoracic veins.

Evaluation Studies as Topic↗
PubMed1992

[Clinical potentialities and limitations of two- and three-dimensional time-of-flight MR angiography in the diagnosis of carotid stenosis].

For diagnosing a carotid artery stenosis, 26 patients underwent MR angiography. A spin echo (SE) sequence with presaturation on which the flowing blood appears with low signal intensity was applied, as well as a two- and three-dimensional gradient echo (GRE) sequence with flow compensation, showing blood flow with high signal intensity. Subsequently, projection angiograms were made from the MR images with a maximum intensity projection algorithm. Degree, length and localisation of a carotid artery stenosis were reviewed. To find out the clinical usability, the results of the MR angiograms were compared subsequently with the findings of intravenous digital subtraction angiography (i.v. DSA). In comparison with DSA a correlation in the degree of stenosis was noticed in 42 out of 48 SE-, in 39 out of 52 2-D GRE and in 41 out of 48 3-D GRE sequence angiograms. The length of 34 moderate and severe stenoses, demonstrated by DSA, was overestimated 5 times with the SE-sequence, 9 times with the 3-D and 23 times with the 2-D GRE sequence. MR angiography with a 3-D GRE sequence is suitable for screening for carotid artery stenosis. In cases of severe stenosis an SE sequence should be performed for more precise delineation of the stenotic lesion.

Aged↗
PubMed1991

[Malignant obstructive jaundice: decompression via an external bilio-gastric fistula].

In cases of malignant bile duct obstruction in which internal biliary drainage cannot be established by surgical intervention or by implantation of a stent, the externally drained bile can be recycled by connecting the transhepatic catheter to a percutaneous gastrostomy. Experiences on three patients treated by the above method are reported.

Adult↗
PubMed1991

[Radiologic study of the ileum-neobladder after radical cystoprostatectomy].

The study reports on radiographic findings obtained from 70 male patients in whom, following radical cystoprostatectomy for carcinoma, an ileum neobladder was created. Morphological appearance and postoperative complications of this continent type of bladder replacement were documented by means of cystography, excretory urography, retrograde urethrography and CT. Specific complications rarely arose from suture insufficiencies of the neobladder itself (n = 3) or from the ileourethral anastomosis (n = 2). Stenoses occurred at the site of the ileourethral (n = 9) and the ureteroileal anastomosis (n = 2). Transient dilatation of the upper urinary tract was observed in the majority of patients. Non-specific complications included pelvic abscesses (n = 2), haematomas (n = 2), lymphoceles (n = 3), and ileus (n = 2).

Adult↗
PubMed1991

[Biliary obstruction: MR-cholangiography with a rapid gradient-echo sequence (2D CE-Fast)].

Magnetic resonance (MR) was used to delineate the biliary tree in patients with obstructive jaundice originating from various types of malignant or benign processes at different locations. With the aid of a rapid sequential gradient-echo acquisition (CE-Fast) and 3D post-processing, heavily T2-weighted images could be obtained to identify the site of obstruction in ten out of eleven patients. Slices were acquired during breath-holding periods of about 12 sec with a total examination time of 10-15 min. The three-dimensional display reliably demonstrated the dilated bile ducts in pre-stenotic areas whereas in the majority of cases post-stenotic ductal segments could not be visualised.

Cholangiography↗
PubMed1991

[Imaging of cerebral flow dynamics using MR angiography and selective pre-saturation: initial experiences].

MR angiography with selective pre-saturation was applied in 5 normal volunteers, 22 patients with cerebrovascular disease, 3 patients with arteriovenous malformations (AVM) and one patient with thrombosis of the superior sagittal sinus. The results were compared with Doppler ultrasound and conventional angiography. MR angiography reliably demonstrated the direction of blood flow and the presence or absence of collateral flow in the circle of Willis. Collateral flow via leptomeningeal vessels and the ophthalmic artery could not be demonstrated. In the patient with superior sagittal sinus thrombosis, the absence of flow was well seen. MR angiography was able to demonstrate the major supplying arteries in the patients with AVMs. MR angiography is a valid noninvasive means to demonstrate direction of flow and blood supply of the major intracranial arteries.

Cerebral Angiography↗
PubMed1991

Dilated biliary tract: evaluation with MR cholangiography with a T2-weighted contrast-enhanced fast sequence.

A heavily T2-weighted gradient-echo sequence was used for magnetic resonance (MR) imaging of the biliary system in five healthy volunteers and 13 patients with obstructive jaundice. Images were obtained in the sagittal and coronal planes during sequential breath-hold intervals and were post-processed by using a maximum-intensity projection algorithm. The extrahepatic and intrahepatic bile ducts were well visualized in 11 patients. The level of obstruction and the grade of dilatation were depicted with MR cholangiography. However, the cause of obstruction could be determined with MR cholangiography in only eight cases. The part of the biliary system below the obstruction could not be visualized with MR cholangiography. In the volunteers, MR cholangiography could demonstrate the anatomy of the biliary tract in only two subjects. Possible causes for this phenomenon are the limited spatial resolution of MR imaging, partial volume effects, or flow within the bile ducts. MR cholangiography may be a useful adjunctive tool for noninvasive evaluation of patients with obstructive jaundice. However, further technical advances are necessary to improve image quality.

Bile Ducts↗
PubMed1991

In-vivo monitoring of corticomedullary nephrocalcinosis in rats using computerized tomography.

An in-vivo method, computerized tomography (CT), was used to monitor nephrocalcinosis in female rats. CT density data correlated well with renal Ca content measured by atomic absorption spectrophotometry. In-vivo CT measurements revealed that the severity of nephrocalcinosis may change spontaneously with time. Manifest calcifications may exhibit spontaneous regression and are probably affected positively by high dietary Mg, in contrast to increased Ca. It is concluded that CT is a suitable and reliable non-invasive in vivo method to follow up time-dependent alterations in kidney calcifications in rats.

Animals↗
PubMed1990

[Drug modification of double-contrast imaging of the small intestine].

The intravenous use of metoclopramid (paspertin) and ceruletid (Takus) reduces the time required for fractionated double contrast examinations of the small bowel. It also improves visualisation of individual sections of the small bowel, particularly the terminal ileum. The value of these drugs has been assessed in a prospective study in 48 patients with suspected Crohn's disease.

Barium Sulfate↗
PubMed1989

[Venous occlusions distant to the shunt as malfunction factors during hemodialysis].

On 78 patients with dysfunction of haemodialysis vascular access (predominantly poor flow) systematic radiographic evaluation was performed. In all cases arteriography was carried out, followed by venous angiography in patients exhibiting occlusion of the arteriovenous fistula or the graft, respectively. In 11 cases (14%) occlusion or significant stenosis of far proximal venous vessels (axillary and/or subclavian vein) could be detected. It is suggested that consecutive deterioration of central venous runoff may induce or aggravate malfunctioning of the shunt and, moreover, may contribute to recurrent thrombosis of arteriovenous fistulae or grafts.

Arm↗
PubMed1989

[Feasibility and relevance of tumor volumetry for stage classification and assessment of remission of germ cell tumors].

Although tumor load has proven to be the most relevant prognostic factor in disseminated germ cell tumors (GCT), methods to determine tumor volume for staging have not been studied so far. In a prospective study, we therefore measured the volume of metastases before and during chemotherapy in 27 patients with disseminated GCT. Abdominal tumor volume was calculated using a General Electric CT scan 8800. Total volume was determined by cumulation of 1 cm slices measured by a cursor. Pulmonary volume was calculated by taking each metastasis as a sphere using V = 0.523 x d3, where V = volume and d = diameter. We used linear regression analysis to determine the dependence of tumor markers on volume. Before chemotherapy, the median tumor volume of all patients was 237 (range 4-2690) cm3. The tumor volume was 1-100 cm3 in 30%, 101-500 cm3 in 41%, and over 500 cm3 in 29% of the patients. NED (no evidence of disease) was achieved in 8/8 patients presenting with a small (1-100 cm3) and 9/10 with a moderate (101-500 cm3) tumor volume. In contrast, only 1/8 with advanced tumor load (greater than 500 cm3) achieved NED. While there was a significant correlation between the initial and the residual tumor volume (P = 0.0024, r = 0.72), there was none between the tumor volume and alpha fetoprotein, beta human chorionic gonadotropin, and lactate dehydrogenase. These results suggest that radiological determination of tumor volume is a reproducible and accurate staging method.

Adolescent↗
PubMed1989

[Detection of osteomyelitis and septic arthritis by nuclear magnetic resonance tomography in children].

Suspected osteomyelitis or septic arthritis, respectively, is usually proven by means of clinical symptoms, laboratory data and microbiologic findings of blood cultures and joint fluids. In the early phase of the diseases conventional X-rays are not helpful. Imaging with isotopes is the most important procedure to describe localisation and extension of the inflammatory processes. Nuclear magnetic resonance imaging as a newer method is capable to detect these inflammatory processes very early, precisely and without discomfort for the patient. In four children with osteomyelitis and in one infant with septic arthritis, respectively, we were able to confirm the clinical diagnosis in a very early phase of the disease. In the patient with septic arthritis nuclear magnetic resonance was the only imaging procedure successfully localising the inflammatory process. Nuclear magnetic resonance imaging localises precisely inflammatory bone and joint diseases during the early stage of the disease.

Arthritis, Infectious↗