利用次谐波造影微泡信号进行体内灌注估计。

In vivo perfusion estimation using subharmonic contrast microbubble signals.

作者信息

Forsberg Flemming, Liu Ji-Bin, Shi William T, Ro Raymond, Lipcan Kathryn J, Deng Xuedong, Hall Anne L

机构信息

Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA 19107 USA.

出版信息

J Ultrasound Med. 2006 Jan;25(1):15-21. doi: 10.7863/jum.2006.25.1.15.

DOI:10.7863/jum.2006.25.1.15

PMID:16371551

Abstract

OBJECTIVE

The purpose of this study was to quantify perfusion in vivo using contrast-enhanced subharmonic imaging (SHI).

METHODS

A modified LOGIQ 9 scanner (GE Healthcare, Milwaukee, WI) operating in gray scale SHI mode was used to measure SHI time-intensity curves in vivo. Four dogs received intravenous contrast bolus injections (dose, 0.1 mL/kg), and renal SHI was performed. After 3 contrast agent injections, a microvascular staining technique based on stable (nonradioactive) isotope-labeled microspheres (BioPhysics Assay Laboratory Inc, Worcester, MA) was used to quantify the degree of perfusion in 8 sections of each kidney. Low perfusion states were induced by ligating surgically exposed segmental renal arteries followed by contrast agent injections and microvascular staining. Digital clips were transferred to a personal computer, and SHI time-intensity curves were acquired in each section using Image-Pro Plus software (Media Cybernetics, Silver Spring, MD). Subharmonic fractional blood volumes were calculated, and the perfusion was estimated from the initial slope of the fractional blood volume uptake averaged over 3 injections. Subharmonic perfusion data were compared with the gold standard (ie, the microspheres) using linear regression analysis.

RESULTS

In vivo gray scale SHI clearly showed flow and, thus, perfusion in the kidneys with almost complete suppression of tissue signals. In total, 270 SHI time-intensity curves were acquired, which reduced to 94 perfusion estimates after averaging. Subharmonic perfusion estimates correlated significantly with microsphere results (r = 0.57; P < .0001). The best SHI perfusion estimates occurred for high perfusion states in the anterior of the kidneys (r = 0.73; P = .0001). The corresponding root mean square error was 2.4%.

CONCLUSIONS

Subharmonic perfusion estimates have been obtained in vivo. The perfusion estimates were in reasonable to good agreement with a microvascular staining technique.

摘要

目的

本研究旨在使用对比增强次谐波成像（SHI）对体内灌注进行定量分析。

方法

采用一台在灰阶SHI模式下运行的改良型LOGIQ 9扫描仪（通用电气医疗集团，威斯康星州密尔沃基）在体内测量SHI时间-强度曲线。4只犬接受静脉注射对比剂团注（剂量为0.1 mL/kg），并进行肾脏SHI检查。在3次注射对比剂后，采用基于稳定（非放射性）同位素标记微球的微血管染色技术（生物物理检测实验室公司，马萨诸塞州伍斯特）对每只肾脏的8个切片的灌注程度进行定量分析。通过手术结扎暴露的节段性肾动脉，然后注射对比剂并进行微血管染色，诱导低灌注状态。将数字片段传输到个人计算机，并使用Image-Pro Plus软件（媒体细胞技术公司，马里兰州银泉）在每个切片中获取SHI时间-强度曲线。计算次谐波分数血容量，并根据3次注射的平均分数血容量摄取的初始斜率估计灌注情况。使用线性回归分析将次谐波灌注数据与金标准（即微球）进行比较。

结果

体内灰阶SHI清晰显示了血流，从而显示了肾脏的灌注情况，几乎完全抑制了组织信号。总共获取了270条SHI时间-强度曲线，平均后减少到94个灌注估计值。次谐波灌注估计值与微球结果显著相关（r = 0.57；P <.0001）。肾脏前部高灌注状态下的次谐波灌注估计值最佳（r = 0.73；P =.0001）。相应的均方根误差为2.4%。