在我們先前研究可知,超音波結合磁振照影劑之多模式對比劑,不但能安全的開啟血腦障壁,並能在磁振T1影像上偵測開啟血腦障壁過程中所造成的腦出血區域。本研究以中心頻率為10MHz的超音波探頭量測微氣泡衰減及生存時間,量測白蛋白微氣泡對比劑(MB)、結合磁振對比劑釓之白蛋白微氣泡對比劑(Gd-MB)、靶向性白蛋白微氣泡對比劑(Av-MB)及結合磁振對比劑釓之白蛋白靶向性微氣泡對比劑(Av-Gd-MB)。另一方面,市售之脂質型之微氣泡對比劑SonoVue及靶向性微氣泡對比劑Targestar SA也同步進行量測以供比較。 由實驗結果可知,結合Avidin之Av-MB及Av-Gd-MB,並不會影響粒徑分布及對比劑的濃度。Av-MB在4-18 MHz有較靈敏的非線性活動而其他的微氣泡介在在6-24 MHz。除此之外,帶有金屬離子的微氣泡對比劑增強了衰減係數。由生存時間結果得知,白蛋白型的微氣泡衰減百分比(34.13%)低於脂質型的微氣泡衰減百分比(61.58%)。而結合Avidin之白蛋白微氣泡都會減少生存時間。此外,帶有金屬離子的白蛋白微氣泡也會影響生存時間。
In previous studies, the potential of using a combined US/MR multimodality contrast agent, albumin-(Gd-DTPA) microbubbles (MBs), for inducing BBB opening and for distinguishing between focused-US-induced BBB opening and intracerebral hemorrhage in MR T1-weighted contrast imaging was explored. In this study, the lifetime and attenuation properties of lipid MBs (SonoVue and Targestar), albumin MBs, avidin albumin MBs, albumin-(Gd-DTPA) MBs and avidin albumin-(Gd-DTPA) MBs at 10 MHz were investigated. The results showed that incorporating of avidin into the albumin-(Gd-DTPA) MBs and avidin albumin-(Gd-DTPA) MBs affects the size distribution and does not affect the production of MBs concentration. The avidin albumin shelled MBs have been found to have more significant nonlinear activity at 4-18 MHz instead of other MBs at 6-24 MHz. Moreover, the MBs incorporated with paramagnetic metal ions increases the intensity of attenuation coefficients. For the lifetime measurement, compared with lipid MBs (SonoVue) 61.58%, the attenuation of albumin MBs was only 34.13%. Avidin conjugation decreased the lifetime either for lipid or for albumin MBs. Paramagnetic metal ions incorporated the shells of albumin MBs also decreases the lifetime of albumin MBs.