PMID: 10405733 | Pallidotomy and thalamotomy with the gamma knife

[janet paterson <janet313@xxxxxxxxxxx>]

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.
<friedm11@xxxxxxxxxxxxxx>
PMID: 10405733, UI: 99334205

<>

janet paterson
52 now / 41 dx / 37 onset
613 256 8340 po box 171 almonte ontario canada K0A 1A0
a new voice: <>
<janet313@xxxxxxxxxxx>