Integration of preoperative and intraoperative functional brain mapping in a frameless stereotactic environment for lesions near eloquent cortex. Technical note.

The authors present a method of incorporating preoperative noninvasive functional brain mapping data into the frameless stereotactic magnetic resonance (MR) imaging dataset used for image-guided resection of brain lesions located near eloquent cortex. They report the use of functional (f)MR imaging and magnetic source (MS) imaging for preoperative mapping of eloquent cortex in difficult cases of brain tumor resection such as those in which there are large expansive masses or in which reoperations are required and the anatomy is distorted from prior treatments. To correlate methods of preoperative and intraoperative mapping localization directly, the authors have developed techniques of importing preoperative MS and fMR imaging data into an image-guided frameless stereotactic computer workstation. The data appear as a seamless overlay on the same preoperative volumetric MR imaging dataset used for stereotactic guidance during the operation. Intraoperatively identified functional locations mapped by cortical stimulation are recorded as digitally registered points. This approach should prove useful in assessing the accuracy and reliability of various preoperative functional brain mapping techniques.

Stereotactic interstitial brachytherapy of malignant astrocytomas with remarks on postimplantation computed tomographic appearance.

Seventeen patients were treated with stereotactically implanted high activity iodine-125 seeds, 12 patients for recurrent malignant astrocytomas (Protocol I) and 5 patients for newly diagnosed glioblastomas (Protocol II). Total radiation dosage to the recurrent tumors in Protocol I, including prior external beam irradiation, averaged 13,500 cGy. In the follow-up period of 6 to 50 months, the survival rate was 93% at 6 months, 60% at 12 months, 50% at 18 months, and 38% at 24 months after implantation. In Protocol II, brachytherapy was used as an interstitial radiation boost to the conventional treatment of newly diagnosed glioblastomas. External beam therapy and interstitial brachytherapy provided 11,000 cGy to these tumors. In the follow-up period of 15 to 27 months, there was a 100% survival at 12 months, 75% at 18 months, and 25% at 24 months after implantation. Eight of our 17 patients required reoperation for persistent or recurrent mass lesions at 6 to 15 months postimplantation; 7 were found to harbor masses of radionecrosis containing nests of anaplastic astrocytes; 1 had frank tumor recurrence. Median survival in this group of patients requiring reoperation was 18.7 months postimplantation. In a review of postimplantation computed tomographic scans, significant mass effect and crossover of hypodensity or enhancement into the corpus callosum or opposite hemisphere were found to have prognostic significance; persistent areas of contrast enhancement and excessive peritumoral hypodensity did not.

Brown-Roberts-Wells stereotactic frame modifications to accomplish magnetic resonance imaging guidance in three planes.

The Brown-Roberts-Wells (BRW) computer tomography (CT) stereotactic guidance system has been modified to accommodate magnetic resonance imaging (MRI). A smaller head ring, which fits in standard MRI head coils, is constructed of a non-ferromagnetic aluminum ring that is split to prevent eddy currents and anodized to prevent MRI image distortion and resolution degradation. A new localizing device has been designed in a box configuration, which allows BRW stereotactic coordinates to be calculated from coronal and sagittal MRI images, in addition to axial images. The system was tested utilizing a phantom and T1- and T2-weighted images. Using 5-mm MRI scan slices, targets were localized accurately to a 5-mm cube in three combined planes. Optimized calibration of both low field strength (0.3 T) and high field strength (1.5 T) MRI systems is necessary to obtain thin slice (5 mm) images with acceptable image resolution. To date, 10 patients have had MRI stereotactic localization of brain lesions that were better defined by MRI than CT.

Real-time three-dimensional graphic reconstructions using Brown-Roberts-Wells frame coordinates in a microcomputer environment.

A desktop microcomputer environment that utilizes Brown-Roberts-Wells (BRW) frame coordinates for creation of three-dimensional depiction of operator-defined intracranial structures has been developed. The system allows direct reading of Siemens CT scan images from a floppy disc, structural edge definition, and reconstruction of defined images. The system is used in the operating room to view scans, perform standard BRW stereotactic functions, and create three-dimensional graphics for such tasks as defining tumor margins, conceptualizing positional relationships of intracranial structures, and radiation planning.

Retinitis secondary to acquired systemic toxoplasmosis with isolation of the parasite.

A 43-year-old woman developed a heterophile-negative infectious mononucleosis syndrome for which no cause was apparent. During her illness she developed subjective changes in the central vision of her right eye and had focal retinal inflammation, which suggested the diagnosis of toxoplasmosis. The clinical course was accompanied by an increased titer to Toxoplasma gondii. Organisms were isolated from lymph node tissue and injected into the peritoneum of mice from which organisms were harvested.

The diagnosis of uveal malignant melanomas in eyes with opaque media.

Of 358 eyes enucleated between 1962 and 1975, and found to contain posterior uveal melanomas, 31 had opaque media (8.6%). Eighteen of these patients with opaque media were seen between 1962 and 1971, before the use of combined ultrasonography and the radioactive phosphorus uptake (32P) test. Melanoma was unsuspected at enucleation in one third of these patients and there was often a long delay in diagnosis. Of the 13 patients seen between 1971 and 1975, after the initiation of combined ultrasonography and 32P) test, there was no delay in diagnosis becuase a melanoma pattern was recognized immediately with ultrasonography and confirmed with a positive 32P test. During the latter part of this study, 19 patients with opaque media had a "melanoma pattern" with ultrasonography. The 32P test was positive in 12 cases and a melanoma was confirmed histologically in every instance. The 32P test was negative in seven cases and all were documented on follow-up to have benign lesions, such as subretinal hemorrhages.

Malignant melanoma arising in a choroidal magnacellular nevus (melanocytoma).

A case is presented of a 55-year-old Caucasian male whose right eye was enucleated for a mixed spindle-A and spindle-B malignant melanoma in 1967. The ophthalmoscopic picture, fluorescein angiography, and overlying peculiar orange pigmentation were suggestive of a malignant lesion. Study of serial sections of the entire lesion made possible the histologic reconstruction of the lesion, clinicopathologic correlation of the yellow-orange pigment, and the location of the nevus and mixed spindle-cell melanoma components.

Intraocular microsurgery: I. New instrumentation (SITE).

The SITE instrument appears to combine advantages of other instruments previously described. It meets the proposed objectives of an efficient cutter where tissue is removed at the front end of the tip. It allows the surgeon complete control of the suction and reflux systems. The instrument is of a simple modular dsign. A fiber optic attachment is available. It is dependable and safe.

Malignant melanomas of the uveal tract in children and young adults.

The Wills Eye Hospital experience with 17 cases of malignant melanoma of the uvea affecting children and young adults was reviewed. They did not appear to differ clinically or histologically from uveal melanomas in older patients, except that in most cases there was a considerable delay in diagnosis, perhaps reflecting a lack of clinical suspicion. Ancillary diagnostic techniques, such as fluorescein angiography, ultrasonography, and 32P studies were often helpful in arriving at the correct diagnosis once the lesion was suspected and referred for evaluation. Malignant melanoma of the uveal tract is not exclusively a disease of old age, and this diagnosis should not be excluded on the basis of the patient's age alone.