ドプラ超音波による健康な犬猫の腎臓と眼の抵抗指数および拍動指数の評価

Resistive index (RI) and pulsatility index (PI) are indirect measurements of blood flow resistance that may be used to evaluate vascular changes in renal and ophthalmologic diseases. To our knowledge, no reports are available describing values for renal and ocular PI index in the unsedated dog and ocular RI and PI indices in the unsedated cat. The purpose of this study was to measure normal values for both intrarenal and ocular RI and PI within the same subject in unsedated clinically normal dogs and cats. Twenty-seven dogs and 10 cats were considered healthy by means of physical examination, CBC, biochemical profile, urinalysis, and ultrasonography. Systolic blood pressure was measured by Doppler ultrasonography. Intrarenal and ocular arteries were scanned by pulsed Doppler ultrasonography to calculate RI and PI. No significant differences were noted between the values obtained for the right vs. the left kidney and eye. The upper values of these indices were calculated as mean + 2 standard deviations resulting in 0.72 and 1.52 for dog renal RI and PI; 0.7 and 1.29 for cat renal RI and PI; 0.76 and 1.68 for dog ocular RI and PI; and 0.72 and 1.02 for cat ocular RI and PI.

抵抗指数（RI）と拍動指数（PI）は、血流抵抗の間接的測定法であり、腎疾患や眼疾患で生じる血管の変化の評価に利用できる可能性がある。我々の知る限り、無鎮静の犬における腎臓と眼底のPI値、そして無鎮静の猫における眼のRI とPI値を報告した研究はない。本研究の目的は、臨床的に健康な犬猫で、腎臓内と眼のRIおよびPIの正常値を無鎮静で測定することであった。27頭の犬と10頭の猫に身体検査、CBC 、生化学検査、尿検査、そして超音波検査を行い、健康とみなした。超音波ドプラ法により収縮期血圧を測定した。超音波パルスドプラ法で腎動脈と眼動脈をスキャンし、RIとPIを算出した。腎臓と眼で左右の測定値に有意差は認められなかった。これらの指数の上限値を平均値+2標準偏差として計算したところ、犬の腎臓のRIとPIがそれぞれ0.72と1.52、猫の腎臓のRIとPIがそれぞれ0.7と1.29、犬の眼のRIとPIがそれぞれ0.76と1.68、猫の眼のRIとPIがそれぞれ0.72と1.02であった。