Boppart S A, Brezinski M E, Pitris C, Fujimoto J G
Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge 02139, USA.
Neurosurgery. 1998 Oct;43(4):834-41. doi: 10.1097/00006123-199810000-00068.
Intraoperative identification of brain tumors and tumor margins has been limited by either the resolution of the in vivo imaging technique or the time required to obtain histological specimens. Our objective was to evaluate the feasibility of using optical coherence tomography (OCT) as a high-resolution, real-time intraoperative imaging technique to identify an intracortical melanoma.
OCT is a new, noncontact, high-speed imaging technology capable of resolutions on the micrometer scale. OCT is analogous to ultrasound B-mode imaging, except that reflections of infrared light, rather than sound, are detected. OCT uses inherent tissue contrast, rather than enhancement with dyes, to differentiate tissue types. The compact, fiberoptic-based design is readily integrated with surgical instruments.
A portable handheld OCT surgical imaging probe has been constructed for imaging within the surgical field. Cadaveric human cortex with metastatic melanoma was harvested and imaged in two and three dimensions. Changes in optical backscatter intensity were used to identify regions of tumor and to locate tumor margins. Structures within the optical coherence tomographic images were compared with the histological slides.
Two-dimensional images showed increased optical backscatter from regions of tumor, which was quantitatively used to determine the tumor margin. The images correlated well with the histological findings. Three-dimensional reconstructions revealed regions of tumor penetrating normal cortex and could be resectioned at arbitrary planes. Subsurface cerebral vascular structures could be identified and were therefore avoided.
OCT can effectively differentiate normal cortex from intracortical melanoma based on variations in optical backscatter. The high-resolution, high-speed imaging capabilities of OCT may permit the intraoperative identification of tumor and the more precise localization of tumor margins.
脑肿瘤及肿瘤边界的术中识别一直受限于体内成像技术的分辨率或获取组织标本所需的时间。我们的目的是评估使用光学相干断层扫描（OCT）作为一种高分辨率、实时术中成像技术来识别皮质内黑色素瘤的可行性。
OCT是一种新型的非接触式高速成像技术，能够达到微米级别的分辨率。OCT类似于超声B模式成像，不同之处在于检测的是红外光而非声音的反射。OCT利用组织固有的对比度，而非染料增强，来区分组织类型。基于光纤的紧凑设计易于与手术器械集成。
已构建了一种便携式手持OCT手术成像探头，用于手术视野内的成像。获取带有转移性黑色素瘤的尸体人类皮质并进行二维和三维成像。利用光学背向散射强度的变化来识别肿瘤区域并定位肿瘤边界。将光学相干断层图像中的结构与组织学切片进行比较。
二维图像显示肿瘤区域的光学背向散射增加，可定量用于确定肿瘤边界。这些图像与组织学结果相关性良好。三维重建显示肿瘤区域穿透正常皮质，并且可以在任意平面进行切除。可以识别大脑皮层下的血管结构，从而避免损伤。
基于光学背向散射的变化，OCT能够有效区分正常皮质与皮质内黑色素瘤。OCT的高分辨率、高速成像能力可能允许术中识别肿瘤并更精确地定位肿瘤边界。
