Dynamic and static phantoms for evaluation of digital subtraction angiographic systems.

Two types of phantoms were developed with which to evaluate the overall performance of digital subtraction angiography (DSA) systems. A dynamic phantom, called a "fish bone" phantom, consists of polyethylene tubes that simulate blood vessels with various lesions, such as stenoses, ulcers, and aneurysms. With this phantom, washout curves were obtained representing the relationship between iodine content and time. It will be useful for qualitative assessment of DSA images, evaluation of different image-processing schemes, and studies of blood flow analysis. A static phantom, called a "C-D" phantom, can be used for measurement of quantitative contrast-detail (C-D) diagrams and for daily monitoring of DSA systems. This was constructed of tubes of seven different diameters (2.15-0.28 mm) and 14 different concentrations of contrast medium (100%-1.1% Renografin-76 [meglumine and sodium diatrizoate]). The C-D diagrams were determined from an observer performance study using C-D phantom images obtained at four different DSA settings.

beta-Endorphin-like immunoreactivity increases in human lumbar cerebrospinal fluid following routine metrizamide myelography.

Much interest has recently been focused on the possible role of the endogenous opiates in the perception of pain in humans. Several investigators have examined the levels of these substances in human cerebrospinal fluid (CSF) in attempts to identify the mechanisms by which electrical stimulation of the brain might induce analgesia. Most of these CSF samples were collected at the time of ventriculography or myelography. In the present study, the levels of beta-endorphin in the CSF of 22 patients undergoing myelography were examined before and after the injection of a contrast agent. beta-Endorphin increased an average of 356% (p less than 0.0005) 15 to 20 minutes following the injection of contrast material into the lumbar subarachnoid space. Thus, routine myelography may have a profound effect on the levels of beta-endorphin measured by radioimmunoassay in human CSF, and great care must be taken in interpreting the significance of changes seen in beta-endorphin levels in CSF collected from patients at the time of myelography or ventriculography. The effect of the injection of contrast material on beta-endorphin immunoreactivity must be distinguished from the postulated effects of any analgesia-inducing therapy.

Cervical and lumbar metrizamide myelography. Split-dose technique.

Good- or excellent-quality cervical and lumbar myelograms may be obtained without exceeding the maximum recommended dose of metrizamide and without using special equipment. With the patient's head down, highly concentrated metrizamide was injected via the lumbar approach to opacify the cervical subarachnoid space. Later, with the patient's head up, additional contrast media was used to opacify the lumbar subarachnoid space. Excellent or good cervical and lumbar myelograms were obtained in 18 of 21 instances.

Detectability of depth information by use of magnification stereoscopic technique in cerebral angiography.

Two types of stereoscopic phantoms were constructed to determine the sensitivity of observers in detecting depth information obtained by means of the magnification stereoscopic technique. One of these, a "plus" phantom, contained perpendicular aluminum wires at the top and bottom of steps of various thicknesses; the observer was asked to identify whether one of the wires was on the top, the bottom, or uncertain in location. The fraction of correct responses versus the height of the step was plotted, indicating the detectability of depth. Fourteen of 20 unselected observers (70%) responded consistently and were considered "good" observers. In general, the greater the stereo shift, the greater the fraction of correct responses. A second phantom, a mesh phantom, contained standard and randomly positioned test wires. The observer was asked to identify the depth position of a test wire with respect to the standard wire if they were in the same plane. It was found that observers can discriminate depth differences of one to two millimeters in magnification stereoscopy, and similar performance for magnification stereoscopic cerebral angiograms is expected.

Computed axial tomography scan demonstration of cerebral edema in eclampsia preceded by blindness.

The presence of cerebral edema in the occipital lobes are demonstrated by computed tomography (CT) in a patient presenting with eclampsia preceded by blindness at 36 weeks' gestation. After delivery by cesarean section, the patient's management included the use of mannitol and dexamethasone (Decadron) to reduce the cerebral edema. The patient's vision returned within 24 hours after delivery. A repeat CT scan confirmed the resolution of the cerebral edema.

Superior sagittal sinus thrombosis diagnosed by computed tomography.

Superior sagittal sinus thrombosis is an often unrecognized clinical condition. This is due to its variable clinical presentation and its association with other serious disease states. The following cases demonstrate that, in the infant, thrombosis of the superior sagittal sinus can be diagnosed quickly and noninvasively by computed tomography (CT). In those clinical situations in which thrombosis of the superior sagittal sinus may occur and neurological changes exist, axial and coronal CT scans may be quite specific in detecting its occurrence.

Intraoperative ultrasound examination of the brain.

In a preliminary demonstration of cranial intraoperative real-time ultrasound, both supratentorial and posterior fossa scans displayed the pertinent anatomy. A grade III astrocytoma was visualized on the supratentorial scan as well. Ultrasound may be valuable for surgical planning and biopsy procedures because of its reliable depiction of intracranial anatomy and ease of use.

Some examples of balloon technology in neurosurgery.

Examples are presented of the use of a compression balloon to treat trigeminal neuralgia, of a dilating balloon to release a web obstruction of the internal carotid artery, of detachable balloons to seal carotid-cavernous and vertebral-venous fistulas, of a temporary occlusive balloon to aid in thrombogenic treatment of a giant aneurysm, and of a temporary occlusive balloon with double or triple-lumen capacity to assist in angiographic diagnosis and to provide reversible carotid occlusion.

CT of subacute sclerosing panencephalitis.

Subacute sclerosing panencephalitis is a progressive, frequently fatal slow virus infection of the brain attacking children and young adults and caused by measles virus. Computed tomography (CT) of the brain in 15 patients with this disease was normal in seven and abnormal in eight. CT demonstrated varying degrees of cortical atrophy associated with focal and multifocal low density lesions of the white matter. Two cases demonstrated low density lesions of the caudate nuclei. The CT lesions were seen in chronic cases and reflect the gliosis and atrophy that occur in this disease. Differential diagnoses include other viral infections and demyelinating and dysmyelinating diseases. Diagnostic laboratory evaluation includes serum and cerebrospinal fluid titers for measles antibodies, cerebrospinal fluid protein electrophoresis, electroencephalography, and cranial CT.

Clinical applications of combined cerebral angiograms and brain CT scans.

This paper illustrates the clinical value of a computer technique for superimposition of two different kinds of imaging procedures. The initial application was to overlay cerebral angiograms onto computed tomograms of the brain. Case material from three patients with intracerebral abnormalities is presented. The sum of information from the combined studies exceeds that from either study alone and has value for both diagnosis and treatment of head lesions.

Localization of intraocular foreign bodies by computed tomography.

An experimental model is presented and the smallest sized metal intraocular foreign body that could be accurately detected by computed tomography was found to be 1 mm in diameter. A 1/2-mm intraocular foreign body was not detected by the computed tomography scan. Computed tomography is an effective method for the precise localization of intraocular foreign bodies.

Multiple meningiomas in the spinal canal.

Previous experimental and clinical observations suggest that radiation is a causative factor in the development of meningiomas. We report a rare case of three spinal meningiomas in a patient who had prior irradiation in the spinal region. The myelographic technique to evaluate multiple spinal canal tumors is outlined.

Treatment of grade III and IV astrocytomas with BCNU alone and in combination with VM-26 following surgery and radiation therapy.

Twenty-one patients with grade III or IV astrocytomas were assigned randomly to receive either BCNU alone or BCNU and VM-26 after surgery and radiation therapy. Patients surviving radiation therapy and receiving single-agent chemotherapy had a median survival of 14 months while those receiving combination chemotherapy had a median survival of 22 months (P greater than 0.05). None of the patients who failed BCNU-only therapy responded to VM-26. Performance status was not affected by either regimen. Computerized tomographic scanning of the brain was useful only in confirming tumor progression. Two patients died from BCNU-related interstitial pulmonary fibrosis.

Cerebrospinal fluid rhinorrhea: localization of dural fistulae using metrizamide, hypocycloidal tomography and computed tomography.

Demonstration of the exact site of the dural fistulae in cerebrospinal fluid rhinorrhea is difficult. This paper presents a technique for accurate localization of these fistulae, using metrizamide cisternography combined with both hypocycloidal tomography and computed tomography.

Delayed traumatic intracerebral hematomas. Report of three cases.

Three patients are reported who developed delayed intracerebral hematomas following closed head injuries. Two patients showed hematomas within 24 hours after a normal computerized tomogram. All three were treated surgically, and two had good results.

Application of longitudinal magnification effect to magnification stereoscopic angiography: a new method of cerebral angiography.

A new method of stereoscopic cerebral angiography has been developed which employs 2X radiographic magnification. In order to obtain the same depth perception in the object as with conventional contact stereoscopic angiography, one can made the x-ray exposures at two focal spot positions which are separated by only 1 inch (2.5 cm), whereas the contact technique requires a separation of 4 inches (10 cm). The smaller distance is possible because, with 2X magnification, the transverse detail in the object is magnified by a factor of two, but the longitudinal detail, which is related to the stereo effect, is magnified by a factor of four, due to the longitudinal magnification effect. The small focal spot separation results in advantages such as improved stereoscopic image detail, better image quality, and low radiation exposure to the patient.