Search PubMed⌕ Search

Biomedical subjects

V Sturm

Publications and source records attributed to V Sturm.

104 records · Page 6Linked to original sources
PubMed1975

[Problems of peripheral nerve surgery in amputation stump pain and phantom limbs].

Follow-up examination of 17 patients with severe and lasting stump and phantom limb pain which could not be improved by analgetics and who then underwent surgical procedures at the neuroma. The results were discouraging. Only 2 patients showed a lasting improvement. Resection of the neuroma and injection of alcohol into the neuroma seem to be successful only if the preoperative history of pain is very short or if there is an isolated injury of a peripheral nerve and a subsequent single neuroma.

Amputation Stumps↗
PubMedDate not supplied

Interstitial irradiation of cerebral gliomas in childhood by permanently implanted 125-iodine--preliminary results.

19 children with a deeply located cerebral glioma were treated with continuous interstitial irradiation (stereotactically implanted 125-iodine). The accumulated dose at the tumor surface ranged in the low grade glioma group (Group A) from 55 to 100 Gy and in the high grade glioma group (group B) from 50 to 65 Gy. Patients in group B additionally received a fractionated external beam irradiation (15-20 Gy boost dose). Tumor shrinkage as seen on CT-scans 6 months postoperatively could be achieved in 100% of patients with a low grade glioma. The response rate of 6 children with a high grade glioma was 83%. With a mean follow up of 57.0 months (group A) and 56.2 months (group B) respectively the estimated 4.5 year survival probability was 92% for low grade gliomas and 83% for grade III/grade IV lesions. Permanent interstitial irradiation offers the possibility of local tumor control with low risk of severe side effects. The survival rates are promising and comparable with results of other study groups. For gliomas grade I and grade II a dose reduction may be feasible.

Adolescent↗
PubMedDate not supplied

Correction of spatial distortion in MR imaging: a prerequisite for accurate stereotaxy.

With magnetic resonance (MR) imaging, accurate spatial information--critical for effective stereotaxy--demands a homogeneous static field and linear gradients. Inhomogeneities and nonlinearities induced by eddy currents during the pulse sequences distort the images and produce spurious displacements of the stereotactic coordinates in both the x-y plane and the z axis. These errors in position can be assessed by means of two phantoms placed within the stereotactic guidance system--a "two-dimensional phantom" displaying "pincushion" distortion in the image (i.e., x, y) plane, and the "three-dimensional phantom" displaying displacement, warp, and tilt of the image plane itself. The pincushion distortion can be "corrected" (reducing displacements from 5 to 1-2 mm) by calculations based on modeling the distortion as a fourth order two-dimensional polynomial. Based on these corrected images, errors in the z coordinate and tilt of image planes may be corrected by adjustment of the gradient shimming currents. Such correction not only implements stereotaxy under MR guidance but also provides for the accurate transfer of anatomic/pathologic information between MR and CT images.

Humans↗
PubMedDate not supplied

Three dimensional image correlation of CT, MR, and PET studies in radiotherapy treatment planning of brain tumors.

A treatment planning system for stereotactic convergent beam irradiation of deeply localized brain tumors is reported. The treatment technique consists of several moving field irradiations in noncoplanar planes at a linear accelerator facility. Using collimated narrow beams, a high concentration of dose within small volumes with a dose gradient of 10-15%/mm was obtained. The dose calculation was based on geometrical information of multiplanar CT or magnetic resonance (MR) imaging data. The patient's head was fixed in a stereotactic localization system, which is usable at CT, MR, and positron emission tomography (PET) installations. Special computer programs for correction of the geometrical MR distortions allowed a precise correlation of the different imaging modalities. The therapist can use combinations of CT, MR, and PET data for defining target volume. For instance, the superior soft tissue contrast of MR coupled with the metabolic features of PET may be a useful addition in the radiation treatment planning process. Furthermore, other features such as calculated dose distribution to critical structures can also be transferred from one set of imaging data to another and can be displayed as three-dimensional shaded structures.

Brain↗
PubMedDate not supplied

Combined use of stereotaxic CT and angiography for brain biopsies and stereotaxic irradiation.

A Riechert Mundinger stereotaxic device was modified to enable artifact-free computed tomographic (CT) scanning with the stereotaxic frame attached to the patient's head. A localization system was developed allowing determination of the XYZ coordinates of the target point directly from the CT cut. Angiography was performed intraoperatively with the stereotaxic frame attached. Coronal and sagittal CT reconstructions were enlarged to the radiographic magnification to allow direct comparison with angiography. CT offered optimum localization of the target, whereas angiography determined the safest approach. Computer programs were developed to enable three-dimensional radiotherapy planning. 125I seeds were implanted for treatment of low-grade gliomas and solid craniopharyngiomas. Yttrium-90 was applied in cystic craniopharyngiomas. Intracavitary rhenium-186 application was abandoned because of frequent cyst recurrence and leakage from the cyst.

Biopsy, Needle↗
PubMedDate not supplied

Intracerebral A lambda amyloidoma diagnosed by stereotactic biopsy.

In a 70-year-old patient with an intracerebral tumor, the very rare diagnosis of an A lambda amyloidoma has been made by stereotactic biopsy using immunohistochemistry with a panel of antibodies directed against amyloid fibril proteins of various origins. The production by an apparent benign monoclonal plasma cell proliferation with secretion of paraproteins into the cerebrospinal fluid is assumed. It is the 4th case in which the amyloid protein was classified as derived from immunoglobulin lambda-light chains and, to our knowledge the first in which an A lambda amyloidoma has been diagnosed intra vitam. The amyloid is restricted to the brain and no systemic involvement has been detected. Therapeutic procedures are discussed.

Aged↗