以犬隻腎臟超音波探討血液灌流指數之物理意義

Abstract

本文研究血液灌流指數VI（Vascularity Index）其所代表血液動力學之意義，主要利用非侵襲性超音波(Echo)系統與侵襲性血流血壓量測系統，以犬隻腎臟為平台，量測其血液灌流量特徵，採用實驗室開發之醫學影像處理軟體分析超音波影像，以探討VI與壓力波和流量波之相關性。 實驗對象為年齡9個月至5歲，重量為14至25公斤之健康犬隻，量測部位為左邊腎臟，非侵襲性實驗總共進行11隻狗的實驗，同時擷取腎臟血管及腹腔大動脈影像資料，針對當中取樣頻率較高的4隻狗將腎臟血管分成葉間動脈（上游）、弓狀動脈（中游）、末稍小動脈（下游）三個部分，並對此三個部分的VI波形，與腹腔大動脈的變形波及流量波進行比對，由比對結果得下游週邊血管統計分析上的相關性高於上、中游血管，VI與變形波迴歸分析的判定係數（ ）分別有0.9371、0.9755、0.8962、0.9037的相關性。藥物實驗總共進行3隻狗的實驗，針對2組較佳的資料資料分析，結果得給藥後平均血壓有下降的趨勢，由86 ± 1 mmHg下降至70 ± 2、72 ± 2、72 ± 1 mmHg，由於Dopamine所影響的是腎臟的血流，以致於給藥後的VI和給藥前腹腔大動脈變形波之間的相關性降低。

This study aimed at investigating the physical meaning of VI（Vascularity Index）, using color duplex ultrasound. The renal hemodynamics of canine was used as the testing platform for the quantification of VI using a medical imaging analysis software developed in house. The dynamics power Doppler VI were compared with the pressure waveform and flow waveform measured upstream at the abdominal aorta. Eleven health dogs aged from nine mouths to five years old, weighted 14- 25 Kg were used in this study. Ultrasonic scanning was focused on the left renal of each dog non-invasively. Both the Doppler spectrum of the renal blood flow and the M-mode image of the abdominal aorta were recorded. Among the test cases, four dogs were selected to differentiate the renal blood vessels at various sections of the kidney; namely interlobar artery（top）、 arcuate artery（middle）、arteriole（below）. Comparing the VI waveforms that obtained from various renal sections with the aortic diameter deformation waveform (which is considered as an alternative pressure waveform) we find the VI waveform from arteriole has a higher correlation statistically than the interlobar artery and the arcuate artery. The corresponding regression analysis were about 0.9371、0.9755、0.8962、0.9037 for these renal VI and the pressure waveform. Dopamine was also used to control the renal blood flow of canine without much alteration of physiological conditions. The blood pressure changed slightly from 86 ± 1 mmHg to 70 ± 2, 72 ± 2 and 72 ± 1 mmHg. Because of the Dopamine affected the renal blood vessels, the regression coefficient between the VI waveform and pressure waveform decreased due to the pharmaceutical action.