Conventional Doppler Sonography Research Articles

Assessment of vascularity in reactive lymph nodes by means of D-galactose contrast-enhanced Doppler sonography.

A prospective study in signal-enhanced Doppler sonography of lymph nodes that were assumed pretherapeutically to be benign was performed to investigate characteristic sonomorphologic features and vascularity of reactively enlarged lymph nodes. Thirty-four patients with enlarged superficial lymph nodes of the neck were examined first by B-scan sonography then by Doppler sonography before and after administration of an ultrasound signal-enhancing agent. In B-scan sonography, lymph nodes were classified into three groups according to their sonomorphologic features: (1) homogeneous parenchyma, (2) a centrally located echogenoic line, and (3) a echogenoic "hilus reflex." In conventional and contrast-enhanced Doppler sonography, peak flow rate, pulsatility index, and resistive index were assessed. Sonomorphologic criteria were compared with histologic findings. Reactively enlarged lymph nodes showed characteristic sonomorphologic patterns correlating to their histologic features. Echogenicity of the hilus corresponded to fibrosis (centrally located echogenoic line in 13 nodes; 38.2%) or fatty involution of the hili (echogenoic hilus reflex in 15 nodes; 44.1%). Administration of the galactose-based ultrasound contrast enhancer facilitated the assessment of hilar vessels, which projected to the echogenoic hili, respectively, actually additionally visualized a hilar vascularity in 10 of the 34 lymph nodes compared with conventional Doppler. Measured Doppler indices gave not a significant clue for identifying reactive lymph nodes or for differential diagnosis. Qualitative sonomorphologic assessment of characteristic sonomorphologic features of reactive lymph nodes may serve as a valuable tool for examining reactively enlarged lymph nodes. Administration of an ultrasound echo enhancer allows the assessment of a characteristic nodal vascularity in reactive lymph nodes and were superior to conventional B-mode and conventional Doppler sonography.

Retrospective review of 400 consecutive free flap reconstructions for oncologic surgical defects.

Free tissue transfer has become an important method for reconstructing complex oncologic surgical defects, allowing single stage reconstruction in most instances. The purpose of this study is to review a single center's experience with free flap reconstruction and describe trends that have evolved with respect to technique and donor site selection. A retrospective review of 400 consecutive free flap reconstructions performed in 396 patients over 10 years was done. Regional applications include the head and neck (63%), trunk and breast (16%), lower extremity (16%), and upper extremity (5%). Donor sites include the fibula (109), rectus abdominis (93), forearm (72), latissimus dorsi (51), scapula (26), gluteus (25), jejunum (16), and five others (8). Microvascular anastomoses were performed to large-caliber vessels using a continuous suture technique; end-to-end anastomoses were preferred. Flaps were designed to avoid the need for vein grafts. Postoperative flap monitoring included clinical observation, conventional Doppler ultrasonography, surface temperature probes, and pinprick testing. The overall free flap success rate was 97%. Twenty-eight flaps (7%) were reexplored, of which seventeen were salvaged (61%). Surviving flaps resulted in a healed wound that did not delay postoperative radiation or chemotherapy. The complication rate was 14%. The mean duration of hospitalization was 21 days, with an average cost of $40,000. The use of fewer, reliable donor sites to reconstruct the vast majority of oncologic defects and the simplification of the microsurgical process have contributed to the success of free tissue transfer in this series.

Power Doppler US of the normal prepubertal testis: does it live up to its promises?

To assess whether power Doppler ultrasound (US) improves the detection of flow in normal prepubertal testes. Seventy-two normal testes of 38 prepubertal boys (age range, 2 weeks to 12.5 years) were scanned with color and power Doppler US (7-MHz transducer). The two modalities were compared subjectively to determine which one was more sensitive for detection of flow. Only reproducible intratesticular flow signals were considered positive; capsular flow was disregarded. Power Doppler US depicted flow in 50 testes (69%), while color Doppler US depicted flow in 47 testes (65%, not statistically significant). Power and color Doppler US combined depicted flow in 57 testes (79%), which was significant when compared with color Doppler US alone (P = .002). Detection of flow was subjectively easier with power Doppler US in 10 of 72 testes, while it was easier with color Doppler US in 14 of 72 testes. Motion artifacts were greater with power Doppler US. Power Doppler US was equally sensitive as conventional color Doppler US in the detection of flow in normal prepubertal testes. Combining both modalities improved detection of flow in 14% of cases and may be useful in excluding torsion in children. For a positive preoperative diagnosis of torsion in children, radionuclide scintigraphy remains the imaging modality of choice.

Possibility of differentiating small hyperechoic liver tumours using contrast-enhanced colour doppler ultrasonography: A preliminary study

We performed a preliminary study to investigate the possibility of differentiating small hyperechoic liver tumours, including hepatocellular carcinomas (HCCs), haemangiomas and focal fatty lesions, by administering a galactose-based contrast agent (SH/TA-508 (Levovist)) during colour Doppler ultrasonography (US). Ten patients (age range: 48-81 years) with small liver tumours (four HCCs, four hemangiomas and two focal fatty lesions) of less than 20 mm in diameter presented with hyperechoic masses with no intratumoural colour signals on conventional colour Doppler US. All patients subsequently underwent colour Doppler US with this contrast agent. Colour Doppler images of the tumours were assessed before and after the intravenous injection of 8 ml of the contrast agent at a concentration of 400 mg/ml. Prior to injection of the contrast agent, no intratumoural colour signals were observed in any cases. After injection, intratumoural colour signals appeared in all HCCs and in two haemangiomas with tumour-margin enhancement. The enhanced colour signals appeared to be related to cardiac contraction in the HCCs, but not in the haemangiomas. In the remaining two haemangiomas, only tumour-margin enhancement was observed. In the focal fatty lesions, neither intratumoural nor tumour-margin enhancement was observed. These results, although preliminary, suggest that the detection of colour Doppler signals is improved by using a contrast agent and the differences between enhanced colour signals from HCCs and haemangiomas may help differentiate hyperechoic HCCs from other hyperechoic tumours, including haemangiomas and focal fatty lesions.

Color Doppler sonographic assessment of placental circulation in the first trimester of normal pregnancy.

Our aim was to study placental circulation during the first trimester of normal pregnancy. For this purpose, 108 single pregnancies from 4 to 15 gestational weeks were evaluated through conventional Doppler ultrasonography. The flow velocity waveforms from the retrochorionic arteries (spiral-radial arteries) and the umbilical artery were assessed using the peak systolic velocity, resistive index, and pulsatility index). Intervillous flow velocity waveform was evaluated from the maximum velocity. The earliest color signal from the retrochorionic circulation was registered at 4.5 weeks along with gestational sac visualization. The venous Doppler signal from the intervillous space and the Doppler signal from the umbilical artery were recorded with an embryo visible from the end of week 5 onward. The retrochorionic, intervillous, and umbilical peak systolic velocities increase, whereas the resistive and pulsatility indices decrease progressively during early pregnancy with a significant correlation with gestational age. Similarly, intervillous maximum velocity gradually increases throughout the first trimester of pregnancy. Despite some methodologic problems related to Doppler technology and the vessels studied color Doppler sonography appears to be an adequate tool to assess the physiologic changes in the placental circulation during early pregnancy.

Quantitative Measurements of Blood Flow Velocity in Basal Cerebral Arteries with Transcranial Duplex Color‐Flow Imaging: A Comparative Study with Conventional Transcranial Doppler Sonography

Transcranial duplex color-flow imaging is a new diagnostic method that allows visual display of blood flow in the basal cerebral arteries. This method allows determination of and correction for the Doppler angle of insonation. Conventional transcranial Doppler sonography has no imaging component and assumes a 0-degree Doppler angle for the calculation of flow velocities. The magnitude of the angle of insonation and the effect on flow velocity estimates have not been clearly defined. In order to evaluate the angle of insonation and the effect of angle correction on velocity readings, 50 patients referred for evaluation of cerebrovascular disease were studied. The mean age was 45 years (range, 24-62 yr). All were examined with conventional transcranial Doppler and transcranial duplex color-flow imaging. Specific vessels of the circle of Willis were identified by location, course, and direction of flow on color-flow images and by depth, direction of flow, and transducer orientation with conventional Doppler sonography. Visually controlled measurements of the Doppler angle of insonation were made by color-flow imaging. The data show that the mean angle of insonation was 33 degrees (+/- 15) in the middle cerebral artery, 35 degrees (+/- 17) in the anterior cerebral artery, 45 degrees (+/- 18) in the posterior cerebral artery, and 15 degrees (+/- 14) in the basilar artery. Angle-corrected peak systolic flow velocities were higher in all vessel segments (middle cerebral = 15%, anterior cerebral = 18%, posterior cerebral = 30%, and basilar = 3%), compared to uncorrected velocity readings by conventional Doppler sonography.(ABSTRACT TRUNCATED AT 250 WORDS)

Minoxidil versus Nitroglycerin: A Prospective Double-Blind Controlled Trial in Transcutaneous Erection Facilitation for Organic Impotence

A new type of topically applied drug (minoxidil) to facilitate erection is presented. Minoxidil acts directly on arterial smooth muscles via relaxation. This drug (1ml. of a 2% solution) was studied under strict laboratory conditions in a double-blind controlled trial on 33 patients (4 with neurogenic plus arterial, 10 with neurogenic and 19 with arterial impotence) and compared to placebo and nitroglycerin (2.5gm. of a 10% ointment). The application sites were the penile shaft (nitroglycerin) or glans penis (minoxidil and placebo). Increases in diameter and rigidity were measured with the RigiScan⁎⁎Dacomed, Minneapolis, Minnesota. device and arterial flow was evaluated by conventional Doppler sonography. Side effects were considered as well.This drug proved to be more active than nitroglycerin and placebo in increasing diameter, rigidity and arterial flow of the penis. The highest activity proved to occur in neurogenically impotent patients. Fewer side effects also were found with minoxidil than with nitroglycerin. For these reasons minoxidil is proposed as a long-term therapeutic agent for organic impotence.

Theory of ultrasound Doppler-spectra velocimetry for arbitrary beam and flow configurations

In conventional ultrasound Doppler systems, the velocity component along the beam axis is derived from the observed frequency shift. Recently, it was verified that by using a pulsed-Doppler system with the beam transversely oriented with respect to the flow, the velocity component transverse to the beam can be derived from the edges of the spectrum. These results are generalized to take into account arbitrary angles of incidence, effects of velocity gradients, arbitrary apertures, and arbitrary source pulses. For uniform apertures and transverse flow, it has been previously shown that the Doppler output spectrum is symmetrical about zero frequency, with its width depending on the Doppler effect due to the transverse velocity and the geometry of the problem. For a beam direction oblique to the velocity, it is shown that the spectrum is now shifted, and is centered about the classical Doppler frequency. For velocity gradients and transverse flows the spectrum remains symmetrical, with the edges corresponding to the maximal velocity; however, the profile becomes peaked at the center. For oblique incidence, an asymmetrical spectrum is obtained and its edges are related to the maximal and minimal velocities within the sampling volume. >