A comparison of blood flow and myocardial O2 consumption (MVO2) in the right and left ventricles was made in 21 open-chest dogs. Simultaneous measurements were made of left anterior descending (LAD) and right coronary arterial blood flow and of O2 saturation in the coronary sinus and in from one to four anterior cardiac veins. Blood flow was greater in the LAD than in the right coronary artery, 87 +/- 5 vs. 46 +/- 3 ml.min-1.100 g-1. Similarly, the O2 saturation was 51 +/- 3% in the anterior cardiac veins and 40 +/- 1% in the coronary sinus. In a subset of seven dogs, the O2 saturation in blood from anterior cardiac veins varied substantially from vein to vein. The mean MVO2 was greater for the left than for the right ventricle, 8.6 +/- 1.4 vs. 4.0 +/- 0.3 ml O2.min-1,100 g-1. Increases in LAD flow with no increase in O2 extraction accounted for enhanced MVO2 of the left ventricle due to pacing, isoproterenol, or methoxamine. In contrast, pacing, isoproterenol, or constriction of the pulmonary artery increased MVO2 of the right ventricle by both augmented O2 extraction and a rise in right coronary blood flow. We conclude that right coronary arterial blood flow is lower per 100 g tissue and is less dependent on MVO2 than is LAD blood flow. The heterogeneity of O2 saturation in anterior cardiac veins suggests that regional differences in MVO2 may exist.

Doppler ultrasound detection of the blood flow associated with liver tumours was studied in primary hepatocellular carcinoma as well as in metastatic liver cancer and haemangioma. Doppler signals were detected from 48 of 55 hepatocellular carcinomas (87.3%), seven of 25 metastatic liver cancers (28.0%) and four of 30 haemangiomas (13.3%). The waveforms of Doppler signals were divided into two types: the pulsatile wave, which was detected from hepatocellular carcinoma (in 35 of the 48 with Doppler signals) and metastatic liver cancer (in all seven with positive signals), and the continuous wave, which was seen from hepatocellular carcinoma (41 out of 48) and haemangioma (in all four with signals). In six patients with hepatocellular carcinoma who underwent transcatheter arterial embolization, the pulsatile wave detected before therapy disappeared immediately thereafter and it is possible that this type of wave originates from tumour vessels. In the study of small, hypoechoic, mass lesions appearing in liver cirrhosis, such signals were also demonstrated, even in eight of 10 small hepatocellular carcinomas less than 2 cm in diameter, whilst they were not detected from nine regenerative nodules related to cirrhotic change. In conclusion, the Doppler ultrasound method may be a useful technique in detecting blood flow within liver tumours and may offer the possibility of a differential diagnosis of small tumours.

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Abstract:We created a new imaging technique that detects and emphasizes turbulence, which is a characteristic of blood flow in hepatocellular carcinoma. We devised two indices that determine a characteristic tumor flow, the bi-directional and lowpeak indices. In the phantom study, both indices of turbulence caused by a stenosis were much higher. In the clinical study, both indices were significantly higher in tumors than in the portal vein or hepatic vein. A turbulent blood flow was detected in 77% of tumors, whereas such detection seldom occurred in the portal or hepatic vein. This technique has the potential to distinguish turbulence in hepatocellular carcinoma. © 1997 John Wiley & Sons, Inc. J Clin Ultrasound 25:183-188, 1997 Keywords: Doppler ultrasound; liver tumor; hepatocellular carcinoma; turbulence; spectral analysis With the improvement in Doppler ultrasound, and in a clinical study, and classified such profiles into three major types (high-peak, flat, and tumor blood flow in the liver has been increasingly studied.1-5 However, it is still difficult to low-peak types) and one subtype (opposing direction type). 6 The high-peak type of flow has the differentiate the blood flow in a tumor from that in non-cancerous tissues based on Doppler findpeak toward the high velocity elements. The flat type has various velocity elements of a similar ings alone.Using a velocity histogram, we analyzed the power. The low-peak type has the peak located toward zero. The opposing direction type is when flow profile. The histogram displays the power distribution of Doppler signals with respect to flow in one direction is mixed with flow in the other direction. the Doppler shift frequency. It was displayed in such a way that frequency was plotted on the abWe found that a turbulent flow created immediately beyond a stenosis appeared as a low-peak scissa and power magnitude on the ordinate. We examined flows both in a phantom experiment and opposing direction type in the phantom study. It was also demonstrated that 39% of tumor blood flows in hepatocellular carcinoma (HCC) showed the opposing direction or low-peak MATERIALS AND METHODS Phantom ExperimentThe turbulent flow created immediately beyond a stenosis (62%) in a phantom model was investigated. The phantom model (No. 316 model, Dansk Fantom Service, Denmark) was a closed circuit system where distilled water with reflectors was pumped into a tube. The tube, made of polyethylene, measured 2.6 mm in inside diameter. It was sharply narrowed to 1.6 mm at one point to create turbulent flows. The pumping of fluid was controlled in such a way that a constant flow was produced. The flow velocity was 41 cm/sec. Starch particles (mean diameter 5 micrometers) in a concentration of 1.0% were the reflector (specific gravity 1.005 g/mL). Specifications of the Doppler phantom were as follows: velocity of sound was 1490 m/sec, back scattering equivalent to normal liver tissue, and attenuation 0.50 Ϯ 0.02 dBcm Ϫ1 MHz Ϫ1. The Doppler signals and velocity histogram of flow P2) to that of...

To study the characteristics of tumor blood flow, flow profiles from hepatocellular carcinomas (39 profiles) and normal hepatic arteries (23 profiles) were evaluated using velocity histograms obtained with Doppler ultrasound. The histograms were classified into three types: (1) high-peak, (2) flat, and (3) low-peak. Characteristically, the low-peak types and the flat types, with flows in opposing directions, were seen only in the tumor vessels. The turbulence in a phantom flow model was of the low-peak type. Spectral analysis revealed that the velocity profile of tumor blood flow was different from that of noncancerous flow and that tumor blood flow was characterized by turbulence.