To segment the tumor region precisely is a prerequisite for ultrasound navigation and treatment. In this paper, a normalized cut method to segment tumor ultrasound image is proposed by means of simple linear iterative clustering for presegmentation procedure. The first step, we use simple linear iterative clustering algorithm to divide the image into a number of homogeneous over-segmented regions. Then, these regions are regarded as nodes, and a similarity matrix is constructed by comparing the histograms of each two regions. Finally, we apply the Ncut method to merging the over-segmented regions, then the image segmentation process is completed. The results show that the proposed segmentation scheme handles the strong speckle noise, low contrast, and weak edges well in ultrasound image. Our method has high segmentation precision and computation efficiency than the pixel-based Ncut method.
目的:评价高强度聚焦超声(high intensity focused ultrasound,HIFU)治疗难治性高血压(resistant hypertension,RH)的安全性和可行性。方法:对40例RH患者行HIFU去肾交感神经术治疗,治疗后随访患者6个月,评估术中及术后不良反应及并发症情况,术后血压下降效果、降压药物种类、肾动脉收缩期流速峰值和肾功能情况。结果:(1)40例患者均完成手术,治疗中主要不适为治疗区疼痛,一般在术后24 h内缓解。术后不良反应均在SIR-A^B级,无一例SIR-C^F级不良反应发生。(2)术后患者左、右肾动脉收缩期流速峰值较术前无差异(P=0.635,P=0.688)。术后患者随访1、6个月血尿素氮、血肌酐、肾小球滤过率较基线无统计学差异(P=0.772,P=0.652,P=0.366)。(3)术后随访1、3、6个月较基线诊室收缩压下降21.5、23.3、22.4 mm Hg(P=0.000),诊室舒张压下降11.1、12.9、12 mm Hg(P=0.000);24 h动态收缩压下降13.6、15.2、14.3 mm Hg(P=0.000),24 h动态收缩压下降5.5、6、4.4 mm Hg(P=0.000);药物种类下降0.8、0.9、1.0种(P=0.000)。结论:HIFU近期治疗RH是安全和可行的,但仍需深入及长期安全性、有效性探索。
