Thirty patients with peripheral arterial disease were evaluated using an ultrasonic duplex scanner. A total of 338 arterial segments from the level of the iliac to the popliteal artery were studied and compared with the results of arteriography read independently by two radiologists who were unaware of the results with the scanner. The results demonstrate that this method is not only suitable for clinical use but is as good as arteriography in defining both the location and extent of the arterial involvement.

Noninvasive mapping of lower limb arterial lesions.

Umbilical artery blood flow characteristics in normal and growth-retarded fetuses

Umbilical and arcuate artery blood flow velocity waveforms (FVW) were recorded in 125 normal singleton pregnancies from 20 to 42 weeks of gestation. The FVW were analysed for pulsatility index (PI), peak systolic velocity/minimum diastolic velocity ratio (S/D ratio), rising slope (RS) and descending slope (DS). Both in the umbilical and arcuate arteries, values for all variables declined with advancing gestation, indicating decreasing placental vascular resistance. The umbilical artery PI was unaffected by the fetal heart rate, but the arcuate artery PI was negatively correlated to the maternal heart rate (r = –0.40). The arcuate artery PI decreased by 0.00394 with each beat per minute increase in maternal heart rate. Normal limits (mean ± 2 SD) were established for umbilical artery PI corrected for gestational age, and arcuate artery Pi corrected for gestational age and maternal heart rate.

Umbilical Artery and Uteroplacental Blood Flow Velocity Waveforms in Normal Pregnancy– A Cross-Sectional Study

https://dspace.library.uu.nl/bitstream/handle/1874/17730/reuver_84_doppler.pdf;sequence=1

Doppler assessment of the fetoplacental circulation in normal and growth-retarded fetuses

Duplex Ultrasound for Assessment of Superior Mesenteric Artery Blood Flow

The blood-velocity/time waveforms over the cardiac cycle obtained from the common femoral arteries of 44 limbs, are defined using Fourier transform and curve-fitting techniques. This results in a third order Laplace transform whose coefficients can be related to distal impedance, proximal lumen diameter and stiffness. The sensitivity of this technique has been investigated in the study of aorto-iliac disease, and compared with single plane arteriography and Pulsatility Index. The results show that the Laplace transform method is a sensitive technique for determining the presence of minor stenoses in the aorto-iliac segment, for determining changes in elastic modulus of the proximal vessels, and for studying changes in distal impedance. Pulsatility Index, is sensitive to the presence of proximal disease but it does not seem able to differentiate between stenoses of less than or greater than 50%. PI is sensitive also to changes in distal impedance, but insensitive to changes in arterial elasticity.

Physiological interpretation of Doppler-shift waveforms-III. Clinical results

Ultrasonic imaging of the carotid artery bifurcation using a 30 channel pulsed Doppler system has been studied in a prospective trial. The results were compared to X-ray contrast angiography. Ninety per cent of the lesions of less than 50% were detected, as were all total occlusions of the internal carotid artery. The overall sensitivity was 93% and specificity 100%. Lateral ultrasonic scans were important in detecting lesions of less than 50% stenosis providing the diagnostic information in 48% of these vessels. The ability to identify both low and high grade stenoses with this system provides a basis for routine screening of patients with suspected carotid disease.

Carotid artery disease: A prospective evaluation of pulsed doppler imaging

A new method is presented for assessing the femorodistal segment in multisegmental arterial disease, using the Laplace transform technique of Doppler waveform analysis. Blood velocity/time waveforms were obtained at femoral and ankle levels in three groups of limbs—50 without arterial disease, 12 with isolated aortoiliac stenoses, and 32 with femoropopliteal occlusions, with and without proximal disease. The waveforms were analyzed for Laplace transform and pulsatility index values. The ω 0 coefficients of the Laplace transform analysis at femoral and ankle levels were compared in each subject, as the ω 0 gradient (femoral/ankle ω 0 ): and pulsatility index damping factor (femoral/ankle Pl) was also calculated. The ω 0 gradient was shown to detect femoropopliteal occlusion in the presence of multisegmental arterial disease and to give some indication of its haemodynamic significance. The diagnostic accuracy of the ω 0 gradient was superior to that of pulsatility index damping factor. When combined with its existing ability to detect aortoiliac stenosis, this new application of the Laplace transform method offers the possibility both of a system for complete localisation of significant arterial lesions, and potential for follow-up of vascular surgical procedures in the lower limb, from two simple Doppler recordings.

Physiological interpretation of Doppler shift waveforms: the femorodistal segment in combined disease.

Doppler arterial waveforms from the femoral and ankle arteries of 55 normal control subjects and 76 arteriopaths were analysed for Laplace transform coefficients, delta and omega omicron, and pulsatility index (PI). At the femoral artery delta was superior to PI in accurately detecting mild and moderate aortoiliac stenosis, as assessed from arteriograms. In the femoropopliteal segment, the ratio of omega omicron from femoral to ankle level compared favourably with PI damping factor in the detection of occlusive disease. The Laplace transform system provides a helpful diagnostic method in lower limb arterial disease.

Differential diagnosis of arterial disease of the lower limb using Doppler ultrasound.

A new method is presented for assessing the femorodistal segment in multisegmental arterial disease, using the Laplace transform technique of Doppler waveform analysis. Blood velocity/time waveforms were obtained at femoral and ankle levels in three groups of limbs--50 without arterial disease, 12 with isolate.d aortoiliac stenoses, and 32 with femoropopliteal occlusions, with and without proximal disease. The waveforms were analysed for Laplace transform and pulsatility index values. The oJ~, coefficients of the Laplace transform analysis at femoral and ankle levels were compared in each subject, as the ~o0 gradient (femoral/ankle w0): and pulsatility index damping factor (femoral/ankle PI) was also calculated. The too gradient was shown to detect femoropopliteal occlusion in the presence of multisegmental arterial disease and to give some indication of its haemodynamic significance. The diagnostic accuracy of the ~o,, gradient was superior to that of pulsatility index damping factor. When combined with its existing ability to detect aortoiliac stenosis, this new application of the Laplace transform method offers the possibility both of a system for complete Iocalisation of significant arterial lesions, and potential for follo,~:-up of vascular surgical procedures in the lower limb, from t',vc simple Doppler recordings.

R.N. Baird

Papers

Physiological interpretation of Doppler-shift waveforms-III. Clinical results

Carotid artery disease: A prospective evaluation of pulsed doppler imaging

Physiological interpretation of Doppler shift waveforms: the femorodistal segment in combined disease.

Differential diagnosis of arterial disease of the lower limb using Doppler ultrasound.

In combined disease