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Nicholas J. Patronas, Javad Hekmatpanah and Kunio Doi

✓ Perfluorocarbon, a new tumor-seeking x-ray contrast agent, was injected into three rats with experimental brain tumors. After 1 to 3 days the rats were sacrificed, and the brains were removed and subjected to x-ray study. All showed dense radiopaque areas which correlated with the size and shape of the corresponding brain tumors. Conversely, none of the radiograms taken of the brain tumor in five rats receiving no perfluorocarbon (control animals) showed similar increased density. These findings suggest that perfluorocarbon may serve a useful role as a contrast medium for computerized tomography studies of brain tumors in man.

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Sean Mullan, Eugene E. Duda and Nicholas J. Patronas

✓ 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.

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Sean Mullan, Frederick D. Brown and Nicholas J. Patronas

✓ Three patients with arteriovenous malformations are described who showed signs of massive hyperemia in the vascular territory of the normal brain proximal to arterial ligation. One additional patient had evidence of ischemia of the brain in the territory distal to ligation (steal), and in another both mechanisms were considered as operative hazards.

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Sean Mullan, Henry Kawanaga and Nicholas J. Patronas

✓ A useful variation of an established technique is described for embolization of cerebral arteriovenous malformations. Silastic sponge emboli that fit into No. 16, 17, and 18 stub adapters are passed through standard-sized transfemoral catheters. Of 28 treated patients, obliteration was regarded as very successful in 16. Partial success was achieved in four. Eight were regarded as failures because the reticulum was too large for these microemboli.

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Edward H. Oldfield, Karin Muraszko, Thomas H. Shawker and Nicholas J. Patronas

✓ The mechanisms previously proposed for the progression of syringomyelia associated with Chiari I malformation of the cerebellar tonsils are controversial, leave many clinical observations unexplained, and underlie the prevalence of different operations currently used as initial treatment. To explore the mechanism of syringomyelia progression in this setting, the authors used anatomical and dynamic (phase-contrast and phase-contrast cine) magnetic resonance (MR) imaging, and intraoperative ultrasonography to examine the anatomy and dynamics of movement of the cerebellar tonsils, the wall of the spinal cord surrounding the syrinx, and the movement of cerebrospinal fluid (CSF) and syrinx fluid at rest, during the respiratory and cardiac cycles, and during Valsalva maneuver in seven affected patients.

In all patients the cerebellar tonsils occluded the subarachnoid space at the level of the foramen magnum. Syringomyelia extended from the cervical to the lower thoracic segment of the spinal cord. No patient had evidence of a patent communication between the fourth ventricle and the syrinx on anatomical MR images, dynamic MR images, or intraoperative ultrasound studies. Dynamic MR images of three patients revealed abrupt downward movement of the spinal CSF and the syrinx fluid during systole and upward movement during diastole, but limited movement of CSF across the foramen magnum during the cardiac cycle. Intraoperative ultrasound studies demonstrated abrupt downward movement of the cerebellar tonsils during systole that was synchronous with sudden constriction of the spinal cord and syrinx. Decompression of the foramen magnum was achieved via suboccipital craniectomy, laminectomy of C-1 and C-2, and dural grafting, leaving the arachnoid intact. Immediately after surgery, the pulsatile downward thrust of the tonsils and constriction of the spinal cord and syrinx disappeared. Syringomyelia resolved within 1 to 6 months after surgery in all patients.

Observations by the authors suggest the following previously unrecognized mechanism for progression of syringomyelia associated with occlusion of the subarachnoid space at the foramen magnum. The brain expands as it fills with blood during systole, imparting a systolic pressure wave to the intracranial CSF that is accommodated in normal subjects by sudden movement of CSF from the basal cisterns to the upper portion of the spinal canal. With obstruction to rapid movement of CSF at the foramen magnum, the cerebellar tonsils, which plug the subarachnoid space posteriorly, move downward with each systolic pulse, acting as a piston on the partially isolated spinal CSF and producing a systolic pressure wave in the spinal CSF that acts on the surface of the spinal cord. This causes progression of syringomyelia by abruptly compressing the cord and propelling the fluid in the syrinx longitudinally with each pulse, and may be responsible for the origin and maintenance of syringomyelia by the pulsatile pressure waves forcing CSF into the cord through the perivascular and interstitial spaces. Effective treatment occurs when the systolic pressure wave transmitted by the cerebellar tonsils is eliminated by relieving the obstruction to rapid movement of subarachnoid CSF across the foramen magnum. The presence of this mechanism can be detected preoperatively on dynamic MR images and during surgery on ultrasound studies by the pulsatile excursion of the wall of the spinal cord surrounding the syrinx and by its immediate disappearance and the expansion of the syrinx during forced inspiration after decompression of the tonsils. Effective treatment is achieved with bone and dural decompression of the foramen magnum alone, without entering the arachnoid.

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Ryszard M. Pluta, Zvi Ram, Nicholas J. Patronas and Harry Keiser

✓ A 42-year-old woman presented with otorrhea 22 years after extracranial resection of a norepinephrinesecreting glomus jugulare tumor with intravascular embolization and radiation therapy to the intracranial portion of the tumor. Tumor growth was arrested and was associated with a decrease in blood and urine norepinephrine levels. Extensive evaluation of the otorrhea, including computerized tomography-cisternography, gadoliniumenhanced magnetic resonance imaging, and arteriography showed marked diffuse necrosis of the temporal bone and skull base with limited tumor vascularity. Cerebrospinal fluid (CSF) collected from the right ear showed norepinephrine levels of 2975 pg/ml; plasma norepinephrine levels were normal. The precise site of CSF leakage could not be delineated. Exploration of the posterior fossa revealed a large dural defect at the anteromedial aspect of the petrous bone through which CSF flowed over the surface of the residual extradural glomus tumor. The defect was successfully sealed with a fascial patch. Postoperatively, CSF norepinephrine levels were normal and no further leakage was observed.

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Michael P. McIlhany, Lydia M. Johns, Thomas Leipzig, Nicholas J. Patronas, Frederick D. Brown and Sean F. Mullan

✓ Partially purified protein from washed and artificially hemolyzed erythrocytes, known to cause significant contractions of isolated canine cerebral vessels in vitro, was injected into the cisterna magna of intact anesthetized dogs. Cerebral blood flow, measured by the xenon-133 washout technique, decreased from a control value of 49.5 ± 1.17 ml/100 gm/min to an experimental value of 34.1 ± 1.65 ml/100 gm/min at 2 hours. Cerebral vascular resistance rose from a control value of 2.05 ± 0.17 PRU (peripheral resistance units) to an experimental value of 2.91 ± 0.25 PRU at 2 hours. Mean arterial blood pressure, heart rate, intracranial pressure, and cerebral perfusion pressure remained stable. Cardiac output also fell significantly (in 2-hour control animals it was 2.89 ± 0.37 liter/min, and in 2-hour experimental animals 1.43 ± 0.13 liter/min) and peripheral vascular resistance rose. These changes were evident by 10 minutes after the cisternal injection of the hemolysate protein, and remained for the duration of the 2-hour monitoring period. Serial vertebrobasilar angiograms demonstrated marked narrowing of the intracranial basilar artery when compared to control values. The narrowing persisted for several days in most animals, and tended to increase with time. Relaxation occurred by the 10th through the 14th day. The authors conclude that this experimental preparation may be a useful model for both in vitro and in vivo investigation of chronic cerebral vasospasm.

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Katelyn Donaldson, Gretchen Scott, Fredric K. Cantor, Nicholas J. Patronas, Martha Quezado and John D. Heiss

Diagnosing and treating patients with persistent neuropathic pain associated with peripheral nerve lesions can be challenging. The authors report the rare case of a painful eccrine spiradenoma treated as a traumatic neuroma for many years because of a history of acute trauma, the presence of a tender palpable mass, and symptoms of allodynia. Surgical excision of the neoplasm completely relieved the pain and hypersensitivity that 2 prior surgeries and other nonsurgical treatments failed to resolve. The diagnosis of eccrine spiradenoma was not established until resection and histopathological analysis of the tissue. This case highlights the need to develop and consider an extensive list of differential diagnoses, including eccrine spiradenoma, for peripheral nerve lesions that fail to respond to treatment.

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Nicholas J. Patronas, Giovanni Di Chiro, Conrad Kufta, Dikran Bairamian, Paul L. Kornblith, Richard Simon and Steven M. Larson

✓ The aim of this study was to determine whether positron emission tomography (PET) with fluorine-18 (18F)-2-deoxyglucose (FDG) can be used as a prognostic test in patients with high-grade cerebral gliomas, regardless of the treatment given. Forty-five patients with astrocytoma Grade III or IV were included in this analysis. The mean survival time of patients with tumors exhibiting high glucose utilization as determined by PET-FDG was 5 months, whereas patients with gliomas showing lower glucose utilization had a mean survival period of 19 months. It is postulated that PET-FDG scans reflect the biological behavior of high-grade astrocytomas and may be used to predict the survival time of patients harboring such neoplasms.

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Stephen C. Saris, Nicholas J. Patronas, Steven A. Rosenberg, Joseph T. Alexander, Joseph Frank, Douglas J. Schwartzentruber, Joshua T. Rubin, David Barba and Edward H. Oldfield

✓ Parenteral treatment with interleukin-2 (IL-2) is effective against certain advanced cancers outside the central nervous system. Prior to commencement of Phase II trials in patients with brain tumors, the neurological and neuroradiological features of 10 patients treated with intravenous administration of repeated doses of IL-2 were studied. Three patients had malignant gliomas, and seven patients had extracranial cancer without evidence of intracranial metastasis. All were treated with intravenous doses of 105 U/kg three times daily for up to 5 days. The patients with gliomas received cranial computerized axial tomography (CT) scans before IL-2 therapy was initiated and during the later stages of treatment. The patients with extracranial cancer under-went T2-weighted magnetic resonance (MR) imaging before and later during therapy.

After two to 11 doses of IL-2, the patients with gliomas had marked neurological deterioration that was associated with a mild to marked increase in peritumoral edema and mass effect visible on CT scans. With cessation of treatment and appropriate supportive care, all returned to their pretreatment state. The patients with extracranial cancer were either neurologically unchanged or underwent minor transient changes in mental status (lethargy and confusion). In these patients, the MR signal intensity was quantified and compared in eight anatomic regions of interest. In six of the seven patients, there were increases in gray and white matter signal intensity consistent with increased cerebral water content. The percentage changes (means ± standard error of the means) were 12.6% ± 7.3% in the gray matter and 17.0% ± 6.2% in the white matter.

This study demonstrates that treatment with a high parenteral dose of IL-2 is not tolerated by patients with gliomas due to increased cerebral edema. In patients with extracranial cancer but no brain disease, parenteral IL-2 induces an increase in the cerebral water content of both gray and white matter.