The role of modern imaging modalities on deep brain stimulation targeting for mental illness.

INTRODUCTION: The reversible nature of deep brain stimulation (DBS) brought renewed interest on surgery to medically intractable mental illnesses. The explosion of anatomical and functional imaging has allowed the development of new potential targets and the understanding of historical targets. METHODS: Fifteen patients undergoing stereotactic surgery for movement disorders, at UCLAs interventional MRI operating-room, were studied with fiber tracking. Stereotactic targets and fiber tracking were determined on MRIs using the Schaltenbrand-Wahren atlas for definition in the iPlan software. Cingulate, subcaudate, BA25/CgWM, amygdala, posterior hypothalamus, orbitofrontal cortex, nucleus accumbens, anterior limb of the internal capsule and dorsomedial thalamus were studied. DTI parameters used ranged from 10 to 20mm for voxel size in the x/y/z planes, fiber length was kept constant at 36 mm, and fractional anisotropy (FA) threshold varied from 0.20 to 0.25. RESULTS: Reliable interconnectivity of targets were determined with DTI and related to PET imaging. Mental illness targets were observed with functional and fiber tract maps. This confirmation yields reliability to DTI imaging in order to determine novel targets and enhance the understanding of areas not well understood. CONCLUSIONS: Currently available imaging techniques, the reversibility of DBS to modulate targets promises to bring a brighter future for surgery of mental illness.

Primary central nervous system lymphoma. Results at the University of California at Los Angeles and review of the literature.

The authors report 24 patients with primary central nervous system lymphoma (PCNSL) treated from 1977 to 1992. There were 13 females and 11 males. Median age was 57 (range: 17-84). Patients were symptomatic for a median of 3 months. Headache was the most common complaint. Median Karnofsky performance score was 70. There were 19 patients with solitary PCNSL, and 5 had multiple deposits. Disease was confined to the supratentorium in 23 patients. Cerebrospinal fluid cytology was positive in 5 of 22 patients examined. All patients received whole-brain irradiation with or without supplemental tumor boost. Tumor doses ranged from 10 to 60 Gy. Intrathecal chemotherapy was administered to 16 patients and 7 received systemic agents. After follow-up ranging from 1 to 66 months, median survival and progression-free survival were each 8 months. One- and 3-year actuarial survival rates were 50% and 36%, respectively. One- and 3-year actuarial progression-free rates were 41% and 15%, respectively. Relapse occurred in 18 patients, and in 17 there was a component of local progression. Lesions recurred in the spinal meninges in 1 patients and in the vitreous in 1. Patients with Karnofsky performance status > or = 70 demonstrated median progression-free survival of 27 months, compared to 4 months for patients < 70 (p = .024). No other significant patient or treatment-related prognostic factors were identified. Clinical dementia occurred in 2 of 11 patients surviving at least 1 year. Review of the literature indicates PCNSL demonstrates relative radioresistance. The most immediate improvement in prognosis for patients with PCNSL can be achieved by properly sequencing systemic and intrathecal chemotherapy with radiation therapy.