脳神経外科領域における四則演算ソフトの臨床応用

Clinical Application of Calculation Software of the Four Rules of Arithmetic on Computed Tomography

I．はじめに

　脳神経外科領域での神経放射線学的診断，脳循環代謝評価は必要不可欠な補助診断となっている．特に，虚血性脳血管障害およびクモ膜下出血後の遅発性脳血管攣縮診断・治療には脳循環代謝評価が重要である．

　われわれは現在までstable xenon（Xe^s）とcomputedtomography（CT）を用いた三次元的局所脳血流量測定（Xes CT-CBF study）^10-13）をルチーンに施行してきたが，加減乗除の四則演算ソフトを導入し脳血流量評価に有用と考えられたのでここに報告する．

Calculation program software of the four rules of arithmetic in computed tomography (CT) has been in-troduced for clinical purposes since 1990.

Evaluation of hemodynamic reserve and cerebral autoregulation can be calculated using this software in ischemic cerebrovascular diseases and delayed cerebral vasospasm after ruptured intracranial aneurysms.

Eight hemodynamic maps can be entered and cal-culation based on the four rules of arithmetic can be performed between them and shown visually. For ex-ample, CBF [CBF after administration of acetazol-amide (B)-CBF before its administration(A)] and % CBF [(B-A)/A×100] maps are useful in evaluation of the capacity of hemodynamic reserve in ischemic cerebro-vascular diseases. And △ CBF [CBF before induced hypertension using intravenous dopamine administra-tion (B)-CBF during induced hypertension (A)] and % CBF [(B-A)/A×100] also can be used in evaluation of cerebral autoregulation and decision concerning indica-tion of the need for induced hypertension (luring the period of delayed cerebral vasospasm after subarach-noid hemorrhage.