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W Y Guo

Publications and source records attributed to W Y Guo.

65 records · Page 4Linked to original sources
PubMed1989

CT of pineal tumors and intracranial germ-cell tumors.

We reviewed 59 cases of pineal tumors and intracranial germ-cell tumors. Most pineal tumors occurred in the first three decades of life, with the exception of pineocytomas, which were seen at a mean age of 34. A male preponderance was noted in the various pineal tumors, except for pineocytomas. The most common tumor of the pineal region was germinoma, which usually showed high density with homogeneously intense enhancement after IV administration of contrast medium. An increased prevalence of pineal calcification was also a feature of pineal germinomas. No characteristic CT features could be found to differentiate among pineal choriocarcinoma, germinoma, embryonal carcinoma, yolk-sac tumor, pineocytoma, and pineoblastoma. CT is useful in detecting intracranial tumors, but the definite diagnosis should depend on pathologic examination and detection of tumor markers in the serum and CSF.

Adolescent↗
PubMed1988

Direct puncture of the cavernous sinus for obliteration of a recurrent carotid-cavernous fistula.

The authors report direct transcutaneous puncture of the cavernous sinus through an intact orbit for embolization of a recurrent carotid-cavernous fistula (CCF) after 10 prior operations. The fistula was obliterated completely with this technique. No significant complication was noted except temporary ptosis for about 2 months. When other approaches are difficult or impossible, this technique can be an alternate way to treat a recurrent CCF after a trapping procedure.

Adult↗
PubMedDate not supplied

Application of MR in stereotactic radiosurgery.

Radiosurgery, a bladeless brain surgery without opening skull, requires higher imaging accuracy as compared to microsurgery. Accordingly, we must refine the ways we use the MR scanner and interpret the obtained images. A well tuned and regularly calibrated MR scanner provides excellent images, which allow us to define detailed intracranial structures without distortion. This enables us to obtain a reliable imaging diagnosis despite the fact that pathologic diagnosis is not available in many radiosurgical patients. Due to its three-dimensional imaging and excellence in tissue and spatial contrast, MR is important in exploring new radiosurgical indications. Large arteriovenous malformations (AVM), dural AVM of cavernous sinus and trigeminal neuralgia are some of the successful examples. By using MR, longitudinal investigation of radiosurgical effects becomes feasible. For tumors, the longitudinal studies are important in optimization of dose selection. For AVM, MR is reliable in verification of radiosurgical result. The reliability is comparable to conventional x-ray angiography. Application of MR enhances the essence of noninvasiveness of radiosurgery.

Brain Neoplasms↗
PubMedDate not supplied

CT and myelogram findings of os odontoideum.

We reviewed the findings of CT and myelogram of cases of os odontoideum. The diagnosis was confirmed by conventional tomogram in all these cases. Four cases were further confirmed by trans-oral decompression. Cartilage was found between the os odontoideum and the odontoid process during operation in these 4 cases. Four of them had no history of trauma and 2 of them had an associated anomaly; one was Down's syndrome, and the other was barrel chest and congenital dislocation of hips. CT findings of os odontoideum in these cases were a constriction and/or a gap of bony structure between the os odontoideum and the odontoid process. Myelograms showed spinal stenosis as a result of atlanto-axial dislocation, or anterior extradural compression from overgrown cartilage and posteriorly dislocated tip of shortened odontoid process.

Adolescent↗
PubMedDate not supplied

Recurrent tumor vs radiation effects after gamma knife radiosurgery of intracerebral metastases: diagnosis with PET-FDG.

OBJECTIVE: Our objective was to differentiate radiation effects from tumor progression in metastases stereotaxically irradiated with the multi-cobalt unit (Gamma Knife). MATERIALS AND METHODS: Eleven patients with stereotaxically irradiated cerebral metastases were examined with PET using [18F]fluorodeoxyglucose (FDG) to differentiate recurrent tumor from radiation effects. RESULTS: Six patients had increased uptake of FDG, and clinical, radiological, and pathological findings confirmed the diagnosis of recurrent metastases. These patients had an unfavorable prognosis and were all dead within 54 weeks after radiosurgery. Five patients had lesions without an increased accumulation of FDG. Four of these patients were alive after a total follow-up of 1.7 years, while one patient died of a peptic ulcer 56 weeks after radiosurgery. CONCLUSION: Positron emission tomography with FDG was of obvious prognostic value in this small series of patients and was clearly superior to CT and MR in the distinction between tumor recurrence and radiation effects (verified necrosis in one case).

Adult↗
PubMedDate not supplied

Stereotaxic angiography in gamma knife radiosurgery of intracranial arteriovenous malformations.

Gamma knife radiosurgery is an effective alternative to embolization or microsurgical removal of small arteriovenous malformations, particularly in eloquent areas of brain tissue. Stereotaxic angiography is a useful diagnostic and targeting adjunct to gamma knife radiosurgery, and the authors present their experience (1,100 patients) with methods and technique, and show how the nidus of the arteriovenous malformation can be defined angiographically. Dose planning employing digitization of the subtraction image enables determination of the spatial coordinates of the lesion by means of an interactive computer program.

Cerebral Angiography↗
PubMedDate not supplied

CT of pineal tumors and intracranial germ-cell tumors.

We reviewed 59 cases of pineal tumors and intracranial germ-cell tumors. Most pineal tumors occurred in the first three decades of life, with the exception of pineocytomas, which were seen at a mean age of 34. A male preponderance was noted in the various pineal tumors, except for pineocytomas. The most common tumor of the pineal region was germinoma, which usually showed high density with homogeneously intense enhancement after IV administration of contrast medium. An increased prevalence of pineal calcification was also a feature of pineal germinomas. No characteristic CT features could be found to differentiate among pineal choriocarcinoma, germinoma, embryonal carcinoma, yolk-sac tumor, pineocytoma, and pineoblastoma. CT is useful in detecting intracranial tumors, but the definite diagnosis should depend on pathologic examination and detection of tumor markers in the serum and CSF.

Adolescent↗
PubMedDate not supplied

Occlusion of arteriovenous malformations of the cavernous sinus via the superior ophthalmic vein.

The treatment of five patients with dural arteriovenous malformations (AVMs) of the cavernous sinus via the superior ophthalmic vein (SOV) is reported. The procedure was performed by transcutaneous puncture of the SOV under the guidance of real-time digital subtraction angiography. Complete resolution of the ocular symptoms was achieved in all cases. Angiograms after embolization showed complete obliteration of the malformation in four cases and partial obliteration in one. This method can cure dural AVMs of the cavernous sinus, with preservation of blood flow in the internal carotid artery. It is particularly indicated when the SOV is enlarged and when (1) dural AVMs of the cavernous sinus are fed by small branches of the internal carotid artery or direct carotid cavernous fistulas with small tears; (2) dural AVMs of the cavernous sinus are fed by multiple branches from both the internal and external carotid arteries, one or both sides; or (3) dural AVMs of the cavernous sinus or direct carotid cavernous fistulas recur after trapping of the internal carotid artery. Transcutaneous puncture and catheterization of the SOV was performed safely with the aid of digital subtraction angiography. The SOV approach was able to treat the fistula with preservation of the internal carotid artery.

Adult↗
PubMedDate not supplied

Radiosurgery as a treatment alternative for dural arteriovenous fistulas of the cavernous sinus.

PURPOSE: Radiosurgery is an effective treatment for cerebral arteriovenous malformations. We conducted the present study to investigate the feasibility and efficacy of gamma knife radiosurgery for dural arteriovenous fistulas (DAVFs) of the cavernous sinus. METHODS: Eighteen patients (12 women and six men; 29-75 years old [mean age, 55 years]) with DAVFs of the cavernous sinus (Barrow's type B:1, C:7, and D:10) treated by gamma knife radiosurgery were enrolled in the study. DAVFs were bilateral in six patients and unilateral in 12. Stereotactic X-ray angiography and MR imaging were performed for targeting the radiosurgery. Areas of arteriovenous communication targeted for irradiation were first outlined on the X-ray angiograms. The target regions were then transferred to and displayed on the MR images. Dose planning was based on findings on the integrated images. Prescribed maximum target doses were 22 to 38 Gy (mean, 28 Gy). The targets were covered by 50% to 90% isodose levels. Radiation doses to the surrounding optic apparatus were kept to less than 8 Gy. The patients were followed up with color Doppler sonography and MR imaging. When noninvasive imaging suggested obliteration, X-ray angiography was performed to verify the results. RESULTS: The DAVFs were totally obliterated in 12 (80%) of the 15 patients. In the other three, one was almost completely obliterated at 14 months and two were partially obliterated at 19 and 27 months, respectively, after radiosurgery. No complications or symptom worsening occurred during the follow-up period. CONCLUSION: Gamma knife radiosurgery is a feasible, effective, and safe treatment for DAVFs of the cavernous sinus. Integration of stereotactic X-ray angiography and MR imaging not only aids treatment efficacy but also protects the relevant vital structures, especially the optic apparatus, from the hazards of radiation.

Adult↗