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Evaluation of the response of metastatic brain
tumors to stereotactic radiosurgery by proton magnetic resonance spectroscopy,
201TlCl single-photon emission computerized tomography, and gadolinium-enhanced
magnetic resonance imaging
Kimura T, Sako K, Tanaka K, Gotoh T, Yoshida H, Aburano T, Tanaka T, Arai H,
Nakada T
Department of Neurosurgery and Radiology, Central Laboratory for
Research and Education, Asahikawa Medical College, Asahikawa, Japan.
tekimura-nsu@umin.ac.jp
Object. The goal of this study was to investigate the usefulness of
proton (1H) magnetic resonance (MR) spectroscopy to evaluate the response of
metastatic brain tumors to stereotactic radiosurgery (SRS) in comparison with
Gd-enhanced MR imaging and single-photon emission computerized tomography with
administration of thallium-201 chloride (201TlCl-SPECT).
Methods. Forty patients with a total of 47 metastatic brain tumors
were evaluated.
The primary lesion was identified in all cases.
Stereotactic radiosurgery was effective in 37 lesions.
All patients were examined using Gd-enhanced MR imaging before and after
SRS.
Thalium-201 chloride was administered to 27 patients with 34 tumors and SPECT
images were obtained.
Proton MR spectroscopy was performed in 36 patients who harbored 43
tumors.
On Gd-enhanced MR images, a decrease in the volume of the Gd-enhanced lesion and
a change in the enhanced effect in the lesion after treatment were recognized as
showing the effectiveness of SRS between 1 and 3 months or more (mean 8.54 +/-
3.58 weeks).
In 201TlCl-SPECT studies, the ratio of lesion to normal brain decreased from 2
weeks to 2 months (mean 5.03 +/- 2.77 weeks) after radiosurgery.
On 1H-MR spectroscopy images a high choline (Cho) peak and a lipid-dominant
(Lip) peak were observed in 25 lesions and a high Cho peak and a
lactate-dominant (Lac) peak were observed in 12 lesions before SRS.
A decrease in the Cho peak, a disappearance of the Lac peak, and an increase in
the Lip peak were observed between 1 week and 1 month (mean 2.76 +/- 1.62 weeks)
after treatment.
Conclusions. Based on histopathological findings obtained at autopsy
or at surgery, we assume that a high Cho peak may be observed in viable tumor
tissue and a Lip peak in areas of necrosis.
The results indicate that 1H-MR spectroscopy is potentially a more sensitive
tool in evaluating the response to SRS than 201TlCl-SPECT or Gd-enhanced MR
imaging and that it can be used earlier for this purpose than those other
imaging methods.
PMID: 15137602 [PubMed - indexed for MEDLINE]
Source: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15137602
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