Nagamachi Shigeki, Fujita Seigo, Nishii Ryuichi, Futami Shigemi, Wakamatsu Hideyuki, Yano Takanori, Kodama Takao, Tamura Shozo, Kunitake Ayumi, Uno Takeshi, Takasaki Mayumi
Department of Radiology, Miyazaki Medical College.
Ann Nucl Med. 2006 May;20(4):303-10. doi: 10.1007/BF02984647.
Chronic pain is defined as intractable pain caused by abnormal pain transmission or impairment of the pain control system per se. Alteration of regional cerebral blood flow (rCBF) is known to occur under the presence of pain stimulation. Epidural spinal cord stimulation (SCS) is occasionally effective in relieving the symptom.
The aim of the current study is to investigate the alteration of rCBF in baseline condition and to find the association between the rCBF change and the efficacy of SCS in chronic pain.
A total of 18 patients underwent Tc-99m-HMPAO SPECT before and after SCS. Analysis with three-dimensional stereo-tactic surface projections (3D-SSP) with stereo-tactic extraction estimation (SEE) software was adopted to evaluate the rCBF. We assessed the extent score of the abnormal region in each segment (rate of the coordinates with a Z-value that exceeds three kinds of threshold value 2.0, 2.5 and 3.0 in all coordinates within a segment). According to the therapeutic response defined by visual analogue scale, we categorized patients into two groups, the good responder (GR) group (n=12) and poor responder (PR) group (n=6). In the analysis, we compared the extent score in the following two conditions. (1) Comparison between the PR group and normal control group under both baseline condition and after SCS. (2) Comparison between the GR group and normal control group under both baseline condition and after SCS.
(1) In the PR group, increased rCBF was observed in left thalamus, bilateral precuneus and bilateral cerebellum under the baseline condition. After SCS, the range of these increased rCBF areas localized but remained. Decrease of rCBF was noted in bilateral subcallosal gyrus, superior temporal gyrus (STG) and bilateral anterior cingulate gyrus (ACG). They localized after SCS, but remained. (2) In the GR group, increased rCBF areas were noted in bilateral precuneus and bilateral cerebellum under the baseline condition. After SCS, they localized in bilateral precuneus but those of bilateral cerebellum remained. Decreased rCBF area was noted in bilateral subcallosal gyrus, STG and bilateral ACG under the baseline. After SCS, they localized in bilateral subcallosal gyrus and bilateral STG. In contrast, they enlarged in bilateral ACG.
Chronic pain patients demonstrated abnormal rCBF distribution on both baseline and post SCS conditions. Increased rCBF of thalamus and precuneus under both conditions in the PR group and decreased rCBF of ACG under post SCS conditions in the GR group were characteristic patterns. Tc-99m-HMPAO SPECT with 3D-SSP and SEE analysis is likely objective and effective in monitoring and evaluating therapeutic outcome by SCS in chronic pain. In addition, it provides information that is useful in the selection of SCS candidates.
慢性疼痛被定义为由异常疼痛传递或疼痛控制系统本身受损引起的顽固性疼痛。已知在疼痛刺激存在的情况下会发生局部脑血流量（rCBF）的改变。硬膜外脊髓刺激（SCS）偶尔对缓解症状有效。
本研究的目的是调查基线状态下rCBF的改变，并找出rCBF变化与SCS治疗慢性疼痛疗效之间的关联。
共有18例患者在SCS前后接受了Tc-99m-HMPAO单光子发射计算机断层扫描（SPECT）。采用带有立体定向提取估计（SEE）软件的三维立体定向表面投影（3D-SSP）分析来评估rCBF。我们评估了每个节段异常区域的范围评分（节段内所有坐标中Z值超过2.0、2.5和3.0这三种阈值的坐标比例）。根据视觉模拟量表定义的治疗反应，我们将患者分为两组，良好反应者（GR）组（n = 12）和差反应者（PR）组（n = 6）。在分析中，我们比较了以下两种情况下的范围评分。（1）PR组与正常对照组在基线状态和SCS后状态下的比较。（2）GR组与正常对照组在基线状态和SCS后状态下的比较。
（1）在PR组中，基线状态下左侧丘脑、双侧楔前叶和双侧小脑的rCBF增加。SCS后，这些rCBF增加区域的范围局限但仍存在。双侧胼胝体下回、颞上回（STG）和双侧前扣带回（ACG）的rCBF降低。SCS后它们局限化但仍存在。（2）在GR组中，基线状态下双侧楔前叶和双侧小脑的rCBF增加区域被观察到。SCS后，它们局限于双侧楔前叶，但双侧小脑的区域仍存在。基线时双侧胼胝体下回STG和双侧ACG的rCBF降低区域被观察到。SCS后，它们局限于双侧胼胝体下回和双侧STG。相比之下，它们在双侧ACG中扩大。
慢性疼痛患者在基线状态和SCS后状态下均表现出异常的rCBF分布。PR组在两种状态下丘脑和楔前叶的rCBF增加以及GR组在SCS后状态下ACG的rCBF降低是特征性模式。采用3D-SSP和SEE分析的Tc-99m-HMPAO SPECT在监测和评估SCS治疗慢性疼痛的疗效方面可能是客观有效的。此外，它提供了有助于选择SCS候选者的信息。
