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Biomedical subjects

B A Kall

Publications and source records attributed to B A Kall.

30 records · Page 2Linked to original sources
PubMed1987

Imaging-based stereotaxic serial biopsies in untreated intracranial glial neoplasms.

Forty patients with previously untreated intracranial glial neoplasms underwent stereotaxic serial biopsies assisted by computerized tomography (CT) and magnetic resonance imaging (MRI). Tumor volumes defined by computer reconstruction of contrast enhancement and low-attenuation boundaries on CT and T1 and T2 prolongation on MRI revealed that tumor volumes defined by T2-weighted MRI scans were larger than those defined by low-attenuation or contrast enhancement on CT scans. Histological analysis of 195 biopsy specimens obtained from various locations within the volumes defined by CT and MRI revealed that: contrast enhancement most often corresponded to tumor tissue without intervening parenchyma; hypodensity corresponded to parenchyma infiltrated by isolated tumor cells or in some instances to tumor tissue in low-grade gliomas or to simple edema; and isolated tumor cell infiltration extended at least as far as T2 prolongation on magnetic resonance images. This information may be useful in planning surgical procedures and radiation therapy in patients with intracranial glial neoplasms.

Adolescent↗
PubMed1986

Results of computer-assisted stereotactic laser resection of deep-seated intracranial lesions.

A computer-assisted stereotactic system has been developed for the precise resection of deep-seated intracranial neoplasms. After the tumor volume is reconstructed from computed tomographic and magnetic resonance imaging data, a computer-monitored, stereotactically directed carbon dioxide laser is used to vaporize the intracranial tumor. A computer graphics terminal is used to monitor the position of the laser in relationship to the planar slices through the tumor, which are reformatted orthogonally to the surgical plane of view. This procedure produced satisfactory postoperative neurologic results in 36 of the 41 patients who underwent treatment. The system provides precise surgical control in three-dimensional space for the safe resection of substantial amounts (as assessed by postoperative computed tomography) of intra-axial neoplasms.

Adolescent↗
PubMed1986

The computer as a stereotactic surgical instrument.

We have developed methodology and stereotactic software for an operating room computer and imaging system. Patients undergo preoperative CT, MR and DSA imaging with their heads fixed in a stereotactic headholder. Localization systems attach to the headholder during the studies to create reference marks for computer transformation of points and volumes into three-dimensional stereotactic space. At the operating room computer console, the surgeon selects target points, avascular trajectories and tumour boundaries for volume reconstruction. Surgical approaches are simulated and target coordinates calculated. During surgery, the computer interactively monitors the position of stereotactically directed surgical instruments in relationship to the resident database along any viewing angle and conveniently superimposes the multiple data sources. We have found this system useful to provide rapid data acquisition and retrieval, accurate target point calculations, lesion volume reconstructions, and a convenient ability to reformat data from multiple sources in a manner useful to the surgeon and beneficial to the patient.

Angiography↗
PubMed1986

Computer-assisted stereotaxic laser resection of intra-axial brain neoplasms.

Computer interpolation of stereotaxic computerized tomography (CT) scanning data allows the transposition of a tumor volume in stereotaxic space. A stereotaxically directed and computer-monitored CO2 laser is then utilized to vaporize that volume as the surgeon monitors the position of a cursor representing the laser beam against planar contours of the tumor displayed on an operating room computer monitor. Computer-assisted stereotaxic laser microsurgery provides precise three-dimensional control for aggressive resection of deep-seated tumors from neurologically important areas with acceptable postoperative results. Thus, a significant cytoreduction can be achieved in addition to providing a tissue diagnosis and internal decompression. The authors report 83 computer-assisted stereotaxic laser procedures for tumor excision in 78 patients. The tumors were located in the thalamus/basal ganglia in 15 patients, ventricular system in five, corpus callosum in four, brain stem in three, and deep and centrally in the hemispheres in 51. Histologically, there were 26 glioblastomas, seven grade III astrocytomas, 14 grade II astrocytomas, 14 metastatic tumors, nine vascular lesions, and eight miscellaneous lesions. Resection of these subcortical lesions was confirmed by postoperative contrast-enhanced CT scanning. Neurological examinations performed 1 week after the 83 procedures revealed that 48 patients had improved from their preoperative level and 23 were unchanged (12 were neurologically normal preoperatively). Twelve patients had an increase in a preoperative neurological deficit, three of whom died in the postoperative period: one from infection, one from pulmonary emboli, and one from brain-stem edema. The average survival period (37.6 weeks) of patients having glioblastomas treated by this technique and irradiation was no different from that of patients having glioblastomas in more favorable locations treated by conventional surgery and irradiation. Patients with circumscribed lower-grade astrocytomas did better in terms of morbidity and completeness of resection than those with infiltrative neoplasms. Other circumscribed lesions, such as metastatic tumors, vascular lesions, and intraventricular tumors, were easily resected by the technique described.

Adolescent↗
PubMed1985

Surgical options for patients with deep-seated brain tumors: computer-assisted stereotactic biopsy.

The histologic nature of deep-seated intracranial lesions can be determined by using a computer-assisted stereotactic biopsy technique. The procedures are performed with use of local anesthesia. A data base consisting of stereotactic computed tomographic scans and stereotactic cerebral angiography is acquired. Target coordinates and trajectory approach angles are calculated by using a computer system in the operating room. Since July 1984, 36 patients with a variety of pathologic lesions in various intracranial sites have undergone this procedure at our institution. Of the 36 patients thought to have neoplastic lesions preoperatively, 6 were found to have nonneoplastic lesions, information that was of importance in the therapeutic management of these patients. Of the 30 patients with tumors, 24 had astrocytomas of various grades, 3 had metastatic lesions, and an additional 3 had lymphomas. Computer-assisted stereotactic biopsy with arteriographic control is an accurate and relatively safe method of determining the histologic nature of any suspicious intracranial lesion.

Adenocarcinoma↗
PubMed1985

Present and future developments of stereotactic technology.

Incorporation of a surgical computer system into stereotactic methodology provides the facility for efficient utilization of the multiple data bases at the disposal of the modern stereotactician. Computed tomography, magnetic resonance imaging, and digital fluoroscopy data gathered in stereotactic conditions are digitized into a stereotactic surgical matrix for surgical planning and interactive surgical procedures. The advantages of this system are illustrated in stereotactic biopsy, interstitial irradiation, and laser resections of intracranial tumors.

Biopsy↗
PubMed1985

Methodology and clinical experience with computed tomography and a computer-resident stereotactic atlas.

We have developed a computer-resident stereotactic atlas of the human brain that quantitatively defines subcortical structures within anatomical landmarks detected on obliquely reconstructed computed tomography (CT) slices. Horizontal stereotactic atlas sections can be stretched and contracted by polar transformation and labeled by a computer to fit within these CT scan-defined landmarks. The stereotactic coordinates of any substructure on the atlas-labeled CT slice may then be calculated by the computer and expressed in mechanical adjustments on a stereotactic surgical frame located in the operating room. We demonstrate the use of this method in the stereotactic treatment of movement disorders as an augmentation to conventional ventriculography and microelectrode recording.

Aged↗
PubMed1984

Transposition of volumetric information derived from computed tomography scanning into stereotactic space.

A method for translation of a tumor volume defined by computed tomography (CT) into stereotactic space using a CT-comparible stereotactic headholder, localizing system, arc--quadrant stereotactic instrument, and operating room computer system is described. Clinical applications, including computer-assisted stereotactic laser resection of deep-seated neoplasms of the central nervous system and simulation of stereotactically implanted radionuclide sources, are discussed.

Brain Neoplasms↗
PubMed1984

Method of computed tomography-based stereotactic biopsy with arteriographic control.

A method for computed tomography (CT)-based stereotactic biopsy of intracranial neoplasms with arteriographic control is described. Stereotactic CT and digitized stereotactic arteriographic data are input to a three-dimensional computer matrix that corresponds to the coordinate system of a stereotactic frame located in the operating room. A site for biopsy is selected by cursor from the CT display screen. The computer calculates and outputs the mechanical adjustments of the stereotactic frame necessary to place the target point into the focal point of the frame. Horizontal and vertical approach angles are determined from the digitized arteriogram and are displayed as settings on the stereotactic frame that represent an avascular trajectory along which the lesion may be biopsied safely. This procedure has been used successfully in 86 patients, with no morbidity or mortality.

Biopsy↗
PubMed1984

Computer simulation for the stereotactic placement of interstitial radionuclide sources into computed tomography-defined tumor volumes.

This report describes a method for the preoperative determination of radioactive interstitial source placement within computed tomography (CT)-defined tumor boundaries. The method utilizes CT data obtained under stereotactic conditions. Tumor boundaries are digitized from CT slices and are retained in a three-dimensional computer matrix. A solid tumor volume is created by an interpolation program and may be sliced orthogonal to any specific stereotactic surgical view line. The surgeon may simulate radioactive source placement within the slices and view the resultant isodose configuration against tumor contours on successive slices. Once the best source placement has been determined, the computer outputs the mechanical adjustments that will be necessary on a stereotactic frame located in the operating room for the stereotactic placement of each source and gives the length of each source. Sources are stereotactically implanted utilizing a double-catheter afterloading technique.

Adult↗