 |
 |
Stereotactic radiosurgical pallidotomy and thalamotomy with the gamma knife: MR imaging findings with clinical correlation--preliminary experience. PURPOSE: To evaluate the temporal evolution and appearance of a radiosurgical lesion at magnetic resonance (MR) imaging and the clinical response in patients undergoing stereotactic radiosurgical pallidotomy or thalamotomy with the gamma knife. MATERIALS AND METHODS: Seventeen patients with medically refractory movement disorders underwent stereotactic radiosurgical pallidotomy (n = 2) or thalamotomy (n = 15). A single dose of 120-140 Gy was administered to a target in the globus pallidus interna or ventralis intermedius thalamic nucleus. Postprocedure gadolinium-enhanced MR imaging and clinical assessment were performed at 1 month and 3 months. RESULTS: At 3 months, the radiosurgical lesion most commonly (n = 11) appeared as a ring-enhancing focus 5 mm or less in diameter surrounded by vasogenic edema that extended less than 7 mm in radius beyond the target. Five patients had ring-enhancing lesions 7 mm or more in diameter; four of these developed symptomatic perilesional edema at 3 (n = 2) or 8 (n = 2) months after the procedure. Onset of therapeutic effect began approximately 4 weeks after treatment. In the 15 patients with tremor, there was a mean decline of 2.1 on the Tremor Rating Scale. CONCLUSION: Findings in this pilot study suggest that radiosurgical thalamotomy is a promising treatment for medically refractory tremor. Three-month follow-up MR studies show a ring-enhancing lesion surrounded by a variable amount of vasogenic edema. Visualization of the radiosurgical lesion and the clinical response are delayed compared to that with radio-frequency procedures. Radiology 1999 Jul;212(1):143-50 Friedman DP, Goldman HW, Flanders AE, Gollomp SM, Curran WJ Jr Department of Radiology, Wills Eye Hospital, Philadelphia, PA, USA. <[log in to unmask]> PMID: 10405733, UI: 99334205 <http://www.ncbi.nlm.nih.gov/PubMed/> janet paterson 52 now / 41 dx / 37 onset 613 256 8340 po box 171 almonte ontario canada K0A 1A0 a new voice: <http://www.geocities.com/SoHo/Village/6263/> <[log in to unmask]>