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SJ Chen

Publications and source records attributed to SJ Chen.

8 recordsLinked to original sources
PubMed2000

A dynamical Bragg equation for high-order Laue zone reflections

A dynamically corrected Bragg equation for high-order Laue zone (HOLZ) reflections is derived directly from the Bloch wave formalism instead of the geometric argument used to deduce the kinematical Bragg condition. It differs from the kinematical Bragg equation by replacing the plane wave vector in the kinematical equation with the Bloch wave vectors. This dynamical equation reduces to the kinematical equation when the crystal potential is zero. It also demonstrates the occurrence of dynamical shifts for the HOLZ reflections but their absence for the zero-order Laue zone (ZOLZ) reflections in the symmetrical Laue case.

Journal Article↗
PubMed1999

Intramedullary cavernous haemangiomas: clinical features, imaging diagnosis, surgical resection and outcome.

The diagnosis, surgical treatment and outcome of seven patients with histologically verified intramedullary cavernous haemangiomas are reported. Five males and two females, with progressive myelopathy were observed. The patients were aged between 7 and 61 years. The duration of their symptoms and signs before diagnosis varied from one month to 5 years. Magnetic resonance (MR) imaging was performed in all patients and spinal angiography was performed in five. All the patients underwent microsurgical resection of the cavernous haemangiomas. MR imaging diagnosed cavernous haemangiomas in all seven patients. T1-weighted images with or without contrast enhancement best defined the margins and size of the lesions. They also illustrated the exophytic components and the change in spinal cord surface well, and were important to surgical planning. T2-weighted images may be suboptimal due to their magnetic susceptibility artifacts. In all lesions, total removal was achieved. Postoperative neurological function improved in all patients in long term follow-up. With the advantages of MR examinations and more understanding about the pathological characteristics of intramedullary cavernous haemangiomas, total removal of the mass lesion should be attempted and the outcome is generally good. Copyright 1999 Harcourt Publishers Ltd.

Journal Article↗