Sugimoto N, Uyama C, Sugahara T, Yanagihara Y
Department of Investigative Radiology, National Cardiovascular Centre Research Institute, Osaka, Japan.
Med Biol Eng Comput. 1994 Jul;32(4 Suppl):S178-84. doi: 10.1007/BF02523345.
To derive blood flow dynamics from cine-angiograms (CAGs), we have developed an image-processing algorithm to determine a two-dimensional blood flow velocity map projected on CAGs. Each image data of CAG is divided into a set of overlapping blocks, and it is assumed that the contrast medium in each block moves only to its 'adjacent blocks' between two serial frames. Based on this assumption, a 'fundamental equation' and the 'maximum flow constraints' are derived. These equations state the relationship between the volume of contrast medium in each block and the volume of contrast medium flowing from/to its 'adjacent blocks'. The volume of the flowing contrast medium is calculated using these relationships, boundary conditions and an additional 'smoothness constraint'. The blood flow velocities are estimated from the volume of the flowing contrast medium and are illustrated with a needle diagram. We applied our algorithm to an abdominal CAG (clinical data). The result showed a vortex flow in the abdominal aneurysm, which was consistent with visual inspection of the CAG movie and with the existence of thrombus in the aneurysm. Our algorithm may be a useful diagnostic tool to assess vascular disease.
为了从电影血管造影（CAG）中获取血流动力学信息，我们开发了一种图像处理算法，用于确定投影在CAG上的二维血流速度图。CAG的每个图像数据被划分为一组重叠块，并假设每个块中的造影剂仅在两个连续帧之间移动到其“相邻块”。基于此假设，推导了一个“基本方程”和“最大流量约束”。这些方程阐述了每个块中造影剂的体积与其流入/流出“相邻块”的造影剂体积之间的关系。利用这些关系、边界条件和一个额外的“平滑约束”来计算流动造影剂的体积。根据流动造影剂的体积估计血流速度，并用针状图进行展示。我们将算法应用于腹部CAG（临床数据）。结果显示腹主动脉瘤内存在涡流，这与对CAG电影的视觉检查以及动脉瘤内血栓的存在情况相符。我们的算法可能是评估血管疾病的一种有用诊断工具。
