In an attempt to overcome the possible radioresistance of glioblastoma multiforme related to the large shoulder on the in vitro survival curves and to sensitize hypoxic tumor cells, a treatment protocol was instituted at Yale University Medical Center and affiliated hospitals, using large dose fraction irradiation therapy in conjunction with the hypoxic cell sensitizer metronidazole. Nineteen patients with biopsy-confirmed, previously untreated, cerebral grade IV glioblastoma multiforme were, following surgery, irradiated once a week at 600 rad per fraction, 3.5 to 4 hours after ingestion of metronidazole, 6 gm/m2. A total of 7 treatments were employed, with all patients maintained on antiseizure medications and corticosteroids. Metronidazole levels were determined prior to each treatment and patients were followed closely clinically and with serial computerized tomography (CT) scans. The treatment was well tolerated, in general, with no untoward side effects related to the high dose fraction irradiation. The majority of the patients experienced varying degrees of gastrointestinal upset lasting up to several hours following metronidazole administration. Three patients died of pulmonary emboli. One patient experienced moderately severe ototoxicity. A median survival of 9.4 months was obtained for all 19 patients, suggestive of a prolongation of survival compared to historical controls treated with conventionally fractionated radiation or with unconventional radiation fractionation schemes and metronidazole or misonidazole.

Adolescent↗

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CT evolution of an acute venous epidural hematoma.

Acute traumatic epidural hematoma may develop secondary to an arterial or venous bleed. The computed tomography (CT scan) appearance of the hematoma depends on the source and severity of bleeding, the interval between injury and CT scan, and the degree of clot organization or breakdown. We report the emergency evaluation, CT scan evolution, and clinical management of one such acute venous epidural hematoma.

Acute Disease↗

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Correction of spinal instability and recovery of neurologic loss following cervical vertebral body replacement. A case report.

While replacement of cervical vertebral bodies may be required when they are compromised by infection, tumor, or injury, or when they impinge on the neural elements, this procedure does not add immediate stability and may cause additional problems. In this case, displacement of a large fibular graft into the spinal canal appeared to cause additional spinal cord and nerve root injury. Despite a long delay, decompression and firmly fitted and wired anterior and posterior grafts seemed to enhance the neurologic recovery and permitted rapid mobilization. The diagnostic value of computerized tomography is also demonstrated.

Adolescent↗

PubMedDate not supplied

Neurologic evaluation of cervical spinal cord injuries.

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Humans↗

PubMedDate not supplied

Surgical results in the treatment of cervical spinal cord injury.

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Cervical Vertebrae↗

PubMedDate not supplied

Dual-energy x-ray projection imaging: two sampling schemes for the correction of scattered radiation.

In addition to the familiar problems of reduced contrast and signal-to-noise ratio (SNR) in the single energy case, dual-energy subtractions in the presence of scattered radiation suffer further degradations from: (1) artifacts due to nonuniform subtraction of scatter, and (2) a serious deterioration of the signal of interest. To determine the expected performance of scatter correcting schemes, we simulated energy subtractions performed in the presence of scatter. We discuss scatter's detrimental effects on contrast and SNR in these simulations and the expected improvements from scatter corrections to within 5% to 10%. We introduce two sampling schemes for the correction of scatter. Each scheme requires two measurements, and each involves placing an x-ray opaque sampling grid between the source and the object. In the first method, the grid is an array of lead disks present only during one measurement. Using these samples we generate an estimate of the scatter field and then subtract it from the second measurement yielding a scatter corrected image. In the second method, the grid is an array of lead strips present during both measurements but displaced between measurements by one-half of a strip spacing to completely sample the image. From the two measurements we generate an image to be corrected, an estimate of the scatter field, and a scatter corrected image. In phantom studies implemented on a digital fluoroscopy system, we observed for single energy images of blood vessel phantoms improved contrast and field uniformity. For scatter corrected selective material cancellations in human phantoms we observed improved contrast and significant reduction in artifacts. In both cases we observed no significant loss in SNR. These results facilitate the implementation of efficient large area detectors for dual-energy imaging.

Algorithms↗

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Two interpolating filters for scatter estimation.

We have previously reported on a dual-measurement sample-and-estimate technique for scatter correction. In this paper, we present a scatter-correction technique that uses the previous sampling scheme but a different method of estimation. To provide samples of the scatter directly, an array of small, uniformly spaced lead disks is placed immediately before the object during only the first measurement. Interpolating from these samples we form an estimate of the scatter. We subtract this estimate from the second measurement to form a scatter-corrected image. Previously, we used least-squares interpolation to estimate the scatter. Because the samples are uniformly spaced, classical sampling theory motivated the investigation of interpolating filters for scatter estimation. To form the scatter image, we convolved the sample set with two different interpolating filters--a sinc function from classical sampling theory and a jinc function because the scatter function is radially symmetric. Using phantoms as objects, we applied both filters for scatter correction in vessel imaging and energy-subtraction imaging. Initial corrected images contained an artifact attributed to aliasing. We modified the filter widths to reduce the aliasing. Although improvements in image quality were measured and the artifact was less pronounced, the artifact was still present. We present the phantom results obtained with this class of filters and discuss methods for its improved performance.

Algorithms↗

PubMedDate not supplied

Cervical bracing after trauma.

Because injudicious movement of the patient with a cervical spine and spinal cord injury can cause additional damage, the cervical spine of the trauma victim suspected of having such an injury must be immobilized at the scene of the accident. A review of the different movements occurring at different levels of the cervical spine indicates that different orthoses--rigid or soft collar, poster brace, cervicothoracic brace, halo appliance--vary in their effectiveness in restricting movement. The semirigid collar, because of its effectiveness in limiting movement and its ease of application, is recommended for immobilizing the cervical spine of a trauma victim.

Braces↗