Intracranial blood flow: quantification with duplex Doppler and color Doppler flow US

The authors compared changes in cerebral blood flow (CBF), determined by means of injection of radiolabeled microspheres, with Doppler blood flow measurements obtained simultaneously in the middle (n = 9) and anterior cerebral arteries (n = 3) in 12 newborn lambs. Doppler estimates of blood flow and mean blood flow velocity correlated well with changes in CBF. However, with changes in mean blood flow velocity, the degree of change in CBF tended to be underestimated. The resistive index correlated well with perfusion pressure but correlated weakly with cerebrovascular resistance and poorly with changes in CBF. Doppler blood flow estimates and mean blood flow velocities correlate well with changes in CBF and allow significant improvement in accuracy over instantaneous velocity or pulsatility measurements alone. Determination of absolute blood flow remains difficult due to systolic and diastolic differences in vessel diameter and intrinsic error in true diameter measurement with currently available color flow technology.     

Patients with breast cancer: differences in color Doppler flow and gray-scale US features of benign and malignant axillary lymph nodes

PURPOSE: To document differences in color Doppler flow and gray-scale ultrasonographic (US) features between benign and malignant axillary lymph nodes in women with primary breast cancer. MATERIALS AND METHODS: The longitudinal-transverse axis ratio and hilar status on color Doppler flow and gray-scale US images were prospectively studied for each of 145 axillary nodes in 135 women (74 palpable nodes in 69 women, 71 nonpalpable nodes in 66 women) with primary breast cancer. Intranodal flow distribution was described as peripheral, central, or central perhilar. Resistive and pulsatility indexes and peak systolic velocity were documented. For comparison of benign and malignant features, nodes were divided into three groups: palpable and nonpalpable, palpable, and nonpalpable. RESULTS: Color flow was demonstrated equally well in benign and malignant axillary lymph nodes for all three groups. For all nodes, peripheral flow was significantly higher in malignant (118 of 153 nodes [77%]) than benign (45 of 160 nodes [28%]) nodes (P <.001); central flow and central perhilar flow were significantly greater (P <.002 and <.001, respectively) in benign than malignant nodes. Similar differences were not observed in nonpalpable nodes. The mean longitudinal-transverse axis ratio (+/- SD) was significantly lower in malignant (1.8 +/- 0.6) than benign (2.6 +/- 0.8) nodes. Logistic regression analysis showed peripheral, central, and central perhilar flow and the mean longitudinal-transverse axis ratio to be significant independent predictors of malignancy. CONCLUSION: Color Doppler flow and gray-scale US features applicable to the identification of disease in palpable axillary nodes in patients with breast cancer are not applicable to nonpalpable nodes.     

Appendiceal involvement in Crohn's disease: gray-scale sonography and color Doppler flow features

OBJECTIVE: The objective of our study was to evaluate appendiceal involvement in Crohn's disease with gray-scale and color Doppler sonography and differentiate it from acute appendicitis. MATERIALS AND METHODS: Analysis of the sonographic examinations was performed over 5 years in 190 patients with an established diagnosis of Crohn's disease. Data analyzed were as follows: visualization of the appendix; thickness and color Doppler signal (grade 0, 1, or 2) of the appendix and adjacent intestinal loop (cecum, terminal ileum, or both); involvement of other intestinal segments; and abscesses. The findings were compared with those of 49 consecutive patients with sonographic findings of acute appendicitis. RESULTS: Thirty-nine patients with Crohn's disease (21%) had appendicular involvement. All but one patient showed thickening of the terminal ileum, and 46% of patients also showed thickening of the cecum. The thickness of the ileum was more than 5 mm (only the anterior wall) in 64% of patients. Appendicular hyperemia was seen in 72% of patients. Involvement of other segments was seen in 23 patients (59%) and adjacent abscesses in six (15%). Irregular thickness of the submucosa was seen in nine cases (23%) and fibrofatty proliferation in 19 (49%). In patients with ileocecal regional disease, ileum thickness of more than 5 mm and visible color in the ileum were the most valuable signs, both for the diagnosis of Crohn's disease and to differentiate it from acute appendicitis (positive predictive value, 96%; negative predictive value, 74%). CONCLUSION: Appendicular involvement in Crohn's disease is a relatively frequent event (21%). Sonography and color Doppler sonography may be useful for differentiating Crohn's disease with appendicular involvement from acute appendicitis.     

Predictors of prostate carcinoma: accuracy of gray-scale and color Doppler US and serum markers

PURPOSE: To determine the accuracy of detecting prostate cancer by using (a) gray-scale and color Doppler transrectal ultrasonography (US), (b) serum and excess prostate-specific antigen (PSA) levels, and (c) targeted and sextant transrectal US-guided biopsy. The relationship between US-detected neovascularity and tumor biologic activity was also evaluated. MATERIALS AND METHODS: Between 1995 and 1999, 544 patients with elevated PSA levels and/or abnormal digital rectal examination underwent transrectal US-guided sextant biopsy and targeted biopsy of US abnormalities. Sensitivity, specificity, and accuracy of gray-scale US, color Doppler US, targeted biopsy, and PSA and excess PSA were calculated. RESULTS: Gray-scale US depicted 78 (41.1%) of 190 cancers, whereas color Doppler US depicted 30 (15.8%) additional cancers. Targeted biopsy was used to detect 108 (56.8%) cancers, whereas sextant biopsy was used to detect 82 (43.2%) additional cancers. Although US-visible cancers had a higher Gleason grade than did cancers discovered at sextant biopsy (P <.05), 25 of the 66 cancers identified with sextant biopsy alone were Gleason grade 6 or higher. Color Doppler US-depicted hypervascularity correlated with biologically aggressive tumors. Excess PSA was normal in 58 (30.5%) cancers, with an accuracy of 67.3%, resulting in better prediction of prostate tumors than with serum PSA level alone. CONCLUSION: Gray-scale transrectal US, even coupled with color Doppler US, is inadequate for prostate carcinoma screening; therefore, targeted biopsy should always be accompanied by complete sextant biopsy sampling.     

Intratumoral blood flow: evaluation with color Doppler echography

Blood flow in several types of tumors (two hepatomas, two hemangiomas, two renal cell carcinomas, one hydatidiform mole, and five invasive moles) was assessed with real-time two-dimensional color Doppler echography (ultrasound). In one of the hepatomas and all five of the invasive moles (but not in the hydatidiform mole or in either of the hemangiomas), the intratumoral flow was demonstrated with color Doppler echography, correlating well with the angiographic or dynamic computed tomographic findings. In the invasive moles, rapid blood flow was seen within the hypoechoic zone of the tumor. On follow-up study of four of the invasive moles, disappearance of the hypoechoic area due to blood flow was observed when chemotherapy was successful. Trophoblastic disease is considered to be the best application for color Doppler echography because it provides accurate evaluation of residual tumor after chemotherapy.     

Hepatocellular carcinoma: evaluation with color Doppler US and MR imaging.

Fifteen patients with hepatocellular carcinoma underwent examination with color Doppler ultrasound (US), magnetic resonance (MR) imaging, dynamic computed tomography (CT), and angiography. Doppler signals ranging from 0.22 to 3.48 kHz could be obtained from within the tumor in 14 of 15 patients. The resistive index was 0.38-0.77. Color Doppler signals were visualized in nine of 15 lesions with a Doppler shift greater than 0.7 kHz. The Doppler signals and the resistive index of the tumor vessels became lower as the vessels progressed into the center of the lesion. The appearance of tumor vessels recognized on MR images obtained with gradient-recalled acquisition in the steady state (GRASS) in 11 of 15 lesions was compared with that on CT scans and angiograms. Tumors that were hyperintense on GRASS images obtained with a flip angle of 15 degrees transmitted Doppler signals of considerably higher amplitude compared with the isointense lesions. Both color Doppler US and MR imaging provided useful information for characterizing intratumoral blood flow.     

Renal blood flow in neonates: quantification with color flow and pulsed Doppler US.

Color flow and pulsed Doppler ultrasound measurements of renal artery blood flow were compared with cardiac output in 22 preterm and 19 full-term healthy neonates. Renal arteries were insonated 3-5 mm from the abdominal aorta at an angle of less than 15 degrees. Vessel diameter was estimated from color flow diameter. Total renal blood flow increased significantly (P less than .001) with advancing birth weight and gestational age, because of increased vessel diameter, but flow velocity did not. The mean (+/- 1 standard deviation) value for both right and left renal artery blood flow was 21 mL/min/kg +/- 5, and the mean proportion of cardiac output to the kidneys was 16.1% +/- 3.7. Seven preterm infants with a symptomatic patent ductus arteriosus had increased cardiac output values (444 mL/min/kg +/- 45) and reduced right (15 mL/min/kg +/- 7) and left (16 mL/min/kg +/- 7) renal artery blood flow, with 6.6% +/- 2.0 of cardiac output directed to the kidneys. These values normalized after closure of the ductus. This study provides normative data for renal artery blood flow in neonates during the first week of life.     

Assessment of fetal swallowing with gray-scale and color Doppler sonography

OBJECTIVE: Our study was focused on the evaluation of fluid dynamics to assess the value of gray-scale and color Doppler sonography for evaluating the development of fetal swallow-related movements from early gestation until birth. MATERIALS AND METHODS: We examined 56 fetuses from weeks 15-39 of gestation. Each fetus was examined throughout four distinct periods of gestation: weeks 15-18, 22-25, 30-34, and 37-39. During the examination, seven gray-scale sonography or color Doppler sonography patterns and their prevalence were considered. RESULTS: Mandibular and/or labial movements (chi2 = 56.4, p < 0.0001) and their rhythmic activity (chi2 = 41.4, p < 0.0001) were seen on gray-scale sonography in an increasing percentage of fetuses as gestational age increased. Doppler findings showed an increase for nose-mouth flow signals (chi2 = 57.6, p < 0.0001), larynx-esophagus flow signals (chi2 = 13.2, p = 0.0003), and effective swallowing (chi2 = 36.0, p < 0.0001) as gestational age increased. CONCLUSION: There is a trend in the fetus toward development of increased coordinated movement and more functional nose-mouth flow with increasing gestational age: 32.1% of the 56 fetuses in our series achieved effective swallowing at 37-39 weeks, on the basis of gray-scale and Doppler evaluations. Knowledge of the physiologic mechanism involving swallowing development may allow identification of altered swallow-related movements in fetuses with malformations of the digestive tract or with neurologic disorders.     

Intracranial venous system in the newborn: evaluation of normal anatomy and flow characteristics with color Doppler US.

To establish the effectiveness of color Doppler ultrasound (US) in identifying flow in the intracranial venous system in newborns, 20 healthy, full-term newborns were scanned. Visualization of the subependymal and internal cerebral veins, superior sagittal sinus, vein of Galen, straight sinus, and left transverse sinus was accomplished in almost every newborn (greater than or equal to 90%). Mean blood flow velocities were as follows: subependymal veins, 3.0 cm/sec; internal cerebral veins, 3.3 cm/sec; inferior sagittal sinus, 3.5 cm/sec; vein of Galen, 4.3 cm/sec; straight sinus, 5.9 cm/sec; and superior sagittal sinus, 9.2 cm/sec. Flow in the subependymal and internal cerebral veins was continuous in all but one newborn (5%), while low-amplitude pulsations were observed with increasing frequency in the more central venous structures such as the vein of Galen (15%), straight sinus (32%), and transverse sinuses (36%). It was concluded that visualization of the intracranial venous system with color Doppler US is possible in the majority of healthy neonates.