Color Doppler Ultrasound Imaging Research Articles

Location of urethral arteries by colour Doppler ultrasound

A case report. Regional Spinal Injuries Centre, Southport, UK. A 56-year-old male with complete paraplegia at T-4 underwent visual internal urethrotomy of bulbous urethral stricture with a cold knife at 12 o'clock position. There was brisk arterial bleeding. Despite receiving antibiotics, this patient developed hypotension, tachycardia and tachypnoea. He was resuscitated and mechanical ventilation was instituted. After he recovered from this life-threatening episode of urinary tract-related sepsis, colour Doppler ultrasound imaging of bulbous urethra was performed to locate urethral arteries. In the bulbous urethra, single urethral artery was seen at 12 o'clock position. Since the sites of urethral arteries vary among patients, it is advisable to assess individually the location of urethral arteries preoperatively and plan the site of incision accordingly. Persons with injury to cervical or upper dorsal spinal cord have decreased cardiac and respiratory reserve as well as alteration in immune function. Therefore, all possible measures should be taken to prevent acute blood loss and bacteraemia in this group of patients.

Umbilical cord entanglement in monoamniotic twins.

Monochorionic–monoamniotic twin pregnancies are a rare obstetric high-risk situation with an estimated frequency of 1 per 25 000 pregnancies. They occur when the division of the morula into two similar totipotent parts takes place between days 9 and 12 after conception. Perinatal mortality is extremely high, ranging between 28% and 70%1. Fetal mortality is caused by prematurity, cord complications and associated congenital anomalies. These days, with the widespread application of sophisticated first-trimester ultrasound, the detection of monoamniotic twin pregnancies can occur earlier and be more precise. Sonographic criteria include single placenta, absence of separating membrane and concordant sex. However, this improved diagnosis has little impact on the regime of surveillance, management and outcome of such pregnancies. While intensive surveillance of monoamniotic twin pregnancies is generally performed, the right time for and mode of delivery are still under discussion. Delivery by Cesarean section at 32 weeks' gestation is recommended by some groups2 in order to avoid intrauterine complications in late pregnancy. However, whether there is excess mortality after 30–32 weeks is questionable. A recent study by Demaria et al.3 of 19 monoamniotic twin pregnancies documented that there were no double fetal deaths after 26 weeks. Delivery of monoamniotic pregnancies by Cesarean section can also help avoid intrapartum accidents of collision and impaction. However, Demaria et al.3 report a 40% rate of uncomplicated vaginal deliveries. The Picture of the Month (Figure 1a) demonstrates prenatal color Doppler imaging of a monoamniotic twin pregnancy in week 26 showing the two very close cord insertions. Under strict surveillance the pregnancy was successfully continued until week 32. Two healthy newborns were delivered via primary Cesarean section after systematic pulmonary maturation. Part (b) illustrates the large umbilical cord entanglement with a very short section of ‘free’ cord in both twins. In this case a cord accident with a tight clinch and entanglement with impaired umbilical perfusion seems probable if the pregnancy had been prolonged. Furthermore, this situation excludes a normal vaginal delivery. In retrospect, a planned Cesarean section in the 32nd week was justified since both newborns showed a normal neonatal adaptation period. (a) Prenatal color Doppler ultrasound image of a monoamniotic twin pregnancy in week 26 showing the two very close cord insertions. (b) Postnatal photograph showing the large umbilical cord entanglement (black arrows) with a very short section of ‘free’ cord (white arrow) in both twins. Knowing that no optimal protocol for the management of monoamniotic pregnancies has been defined, we believe that sonographic investigation and documentation of the umbilical cord may contribute helpful information to the decision-making process.

Feasibility and accuracy of pre-procedure imaging of the proximal cephalic vein by duplex ultrasonography in pacemaker and defibrillator implantation.

Failure of the cephalic venous approach in pacemaker and defibrillator implantation is always due to the small size and difficulty in isolation of the cephalic vein. We propose that pre-procedure imaging of the proximal cephalic vein is valuable to achieve successful access of cephalic vein. However, the feasibility and accuracy of duplex ultrasonographic imaging of the proximal cephalic vein are unknown. The study enrolled 30 consecutive patients who underwent new implantation of permanent pacemakers or defibrillators at our institute. An ultrasound probe scanned along the plane 2 cm beneath the inferior margin of the clavicle to locate the cephalic vein before device implantation. If the vein was well visualized, the venous diameter and the vertical depth were measured. The corresponding surface location of the vein on the chest wall was also identified and recorded by duplex ultrasonography. The echo-derived vertical depths and vascular findings were compared with those measured during surgery. All proximal cephalic veins were well visualized in the infraclavicular region by duplex ultrasonography. They were compressible, patent in color Doppler ultrasound imaging, and displayed phasic change of Doppler signal during respiration, indicating patency in all study veins. The average diameter of the target cephalic vein was 7.7 +/- 1.6 mm (range, 5.0-11.1 mm). The echo-derived vertical depth of the proximal cephalic veins was highly correlated with the depth measured during surgery (28.4 +/- 5.5 vs. 28.4 +/- 5.6 mm, r = 0.93, P < 0.0001). All target cephalic veins were isolated after exploration via the estimated surface location of the chest wall by pre-procedure duplex ultrasonography. Seven (23%) of the studied patients did not have their cephalic vein cannulated successfully. The target proximal cephalic vein in pacemaker and defibrillator implantation can be precisely imaged and localized by duplex ultrasonography. Although further studies are needed, our findings pave a way to further study and clarify the implantation problems of cephalic vein approach.

System and method for post-processing ultrasound color doppler imaging

A system for ultrasonic imaging that includes a comparator for comparing at least one Doppler parameter input to a threshold value and generating a first mask. The comparator has a threshold value associated with each Doppler parameter input. A spatial filter is coupled to the comparator and produces a second mask, and a classification operator is coupled to the spatial filter and generates a third mask. The classification operator can effectively compare a value of a given pixel to the value of any nearby neighboring pixels and reclassify any given non-majority pixel to a majority value of the nearby neighboring pixels. An embodiment of the invention further includes a multi-parameter generator that outputs at least one Doppler parameter. The multi-parameter generator has a functional relationship based on at least one Doppler parameter input and at least one of any of the masks. A second spatial filter is coupled to receive the Doppler parameter input.

Tailored operative technique for Chiari type I malformation using intraoperative color Doppler ultrasonography.

We describe an operative technique for Chiari Type I malformation that uses color Doppler ultrasonography as a guide for performing patient-specific posterior fossa decompressions. The technique has been used since 1999 in more than 300 operations. On the basis of real-time anatomic and physiological measurements, the following goals of surgery were monitored: 1) adequate decompression of the cervicomedullary junction; 2) creation of a retrocerebellar space of 8 to 10 cm(3) volume; and 3) establishment of optimal cerebrospinal fluid flow between the cranial and spinal compartments. The size of the craniectomy was tailored to conform to the area of cerebellar impaction as demarcated by compressed subarachnoid spaces. A laminectomy was not performed unless the cerebellar tonsils were herniated below C1. Before opening the dura, color Doppler ultrasonography imaging was invaluable in planning operative strategies. A simple duraplasty without additional steps was found to be appropriate treatment in occasional patients with minimal tonsillar herniation (5-8 mm). In all other cases, it was necessary to perform an internal decompression that included lysis of the arachnoid and shrinkage of the cerebellar tonsils to achieve the goals of surgery. Optimal cerebrospinal fluid flow through the foramen magnum in anesthetized, prone patients was found to have the following characteristics: a peak velocity of 3 to 5 cm/s, bidirectional movement, and a waveform exhibiting vascular and respiratory variations. The attainment of surgical goals was confirmed in most patients by postoperative neuroimaging. Color Doppler ultrasonography imaging is an important technological advance that permits the neurosurgeon to tailor the steps of Chiari surgery according to patient-specific variables. The success of this technique depends on the mastery of a new and sophisticated monitoring modality.

Color Doppler Ultrasound Guidance During Renal Angioplasty and Stenting

Purpose:To investigate whether an imaging technique combining color Doppler ultrasonography and selective renal artery digital subtraction angiography reduces contrast requirements in patients with progressive renal insufficiency undergoing renal artery angioplasty and stenting.Methods:Eight patients (5 men; mean age 58 years) with renal artery stenosis and renal insufficiency underwent percutaneous transluminal angioplasty and stenting under color Doppler ultrasound guidance.Results:Color Doppler ultrasound imaging yielded the information necessary for verifying catheter position, stent placement and expansion, and hemodynamics after revascularization. The combined imaging technique considerably reduced contrast requirements to only 10 mL in each case. No worsening of renal function was seen in any patient.Conclusions:The combined imaging procedure uses low doses of contrast agent and is especially suited to patients with renal dysfunction undergoing percutaneous renal revascularization.

P236: The cylindrical shape of ductus venosus in the first trimester of gestation

Objective: To investigate the geometric shape of the ductus venosus between 10–13 weeks of gestation. Patients and methods: Ductus venosus measurements were performed in 64 normal human fetus using ultrasound color Doppler imaging. The geometrical measurements obtained were: length (n = 64), isthmic width (n = 34) and outlet width (n = 20). For statistical analysis, the analysis of variance, linear regression, Kruskal-Wallis terst and the Spearman correlation were used. Results: At 10–13 weeks of gestation, the ductus venosus length indicates a continuous growth and the width did not change. The measurements (median) were: length = 2 mm, isthimic inlet = 1.4 mm, and outlet width +1.4 mm. Conclusion: The new geometric shape of the ductus venosus between 10–13 weeks of gestation has a cylindrical and not a slender trumpet-like shape as defined previously in the literature.

Tumor vessel destruction resulting from high-intensity focused ultrasound in patients with solid malignancies

The purpose of this study was to explore the sequential imaging and histologic alterations of tumor blood vessels in the patient with solid malignancies after extracorporeal treatment of high-intensity focused ultrasound (HIFU). A total of 164 patients underwent extracorporeal HIFU ablation of malignant solid tumors. After HIFU treatment, enhanced magnetic resonance imaging (MRI), color Doppler ultrasound (US) imaging, dynamic radionuclide scanning, digital subtraction angiography, and histologic study were performed to monitor the response of tumor vessels to HIFU ablation. Compared with tumor images in the patients before HIFU, clinical images showed an abrupt interruption, followed by the cessation of blood flow within the tumor vessels after HIFU treatment. The histologic examination indicated that not only the treated tumor cells showed coagulative necrosis, but also small tumor vessels were severely damaged by the HIFU treatment. The results strongly imply that the damaged tumor vessels might play a critical role in secondary tumor cell death, and then indirectly strengthen the destructive force of focused US beams on tumor tissue. It is concluded that tumor vessel damage can be induced by HIFU, which may be a promising strategy in the treatment of patients with solid malignancies. (E-mail: mfengwu@yahoo.com)

Gray-scale and doppler ultrasound imaging features of vascular canals in human femoral condylar epiphysis

To describe the gray-scale and color Doppler ultrasound imaging features of vascular canals in human femoral condylar epiphysis. Vascular canals in the femoral condylar epiphysis were examined using gray-scale and Doppler US. The study was performed in 45 volunteers (aged <1 month-72 years) who comprised 1 subject with short stature, 1 subject with Klippel-Trenaunay-Weber syndrome and 43 subjects with normal growth. In the 8-year-old and younger group (n=34), vascular canals were observed in 32 subjects (94%), whereas vascular canals were not observed in the 9-year-old and older group (n=11). Vascular canals were visualized as hyperechoic lines and dots. With Doppler US, blood flow in the vascular canals was observed in 20 of the 32 subjects (62.5%). Spectral Doppler analysis was possible in 15 subjects, in all of whom only arterial waveforms were observed. US was helpful to delineate the vascular canals and flow therein. The detection and evaluation of vascular canals and blood flow therein may prove useful in understanding growth.

Gray-scale and Doppler ultrasound imaging features of vascular canals in human femoral condylar epiphysis.

To describe the gray-scale and color Doppler ultrasound imaging features of vascular canals in human femoral condylar epiphysis. Vascular canals in the femoral condylar epiphysis were examined using gray-scale and Doppler US. The study was performed in 45 volunteers (aged <1 month-72 years) who comprised 1 subject with short stature, 1 subject with Klippel-Trenaunay-Weber syndrome and 43 subjects with normal growth. In the 8-year-old and younger group (n=34), vascular canals were observed in 32 subjects (94%), whereas vascular canals were not observed in the 9-year-old and older group (n=11). Vascular canals were visualized as hyperechoic lines and dots. With Doppler US, blood flow in the vascular canals was observed in 20 of the 32 subjects (62.5%). Spectral Doppler analysis was possible in 15 subjects, in all of whom only arterial waveforms were observed. US was helpful to delineate the vascular canals and flow therein. The detection and evaluation of vascular canals and blood flow therein may prove useful in understanding growth.

Color Doppler ultrasound for detection of renal arteriovenous fistulas

Renal arteriovenous (AV) fistula is uncommon, but sometimes causes severe hematuria. To assess the value of color Doppler ultrasound (CD-US) for the detection of renal AV fistula, we retrospectively reviewed our experience with this disease. Between 1994 and 2001, five patients with renal AV fistula were diagnosed in our institution. Post-biopsy AV fistula of the transplanted kidney was found in 1 patient. Renal AV fistula was detected in 2 patients who presented with gross hematuria. In the remaining 2 patients, renal AV fistula was discovered incidentally during abdominal ultrasonography. We evaluated gray-scale and CD-US imaging in those five patients. In all 5 patients, CD-US showed a whirling flow pattern within an echo-free structure suggesting AV fistula. However, it was difficult to distinguish AV fistula from aneurysm using only CD-US. While pulsed spectral Doppler evaluation of the lesion might be helpful, prompt venous filling on dynamic CT scan and/or renal arteriography was the most definitive sign for diagnosing the renal AV fistula. CD-US is excellent for demonstrating turbulent blood flow signals within the kidney. However, another radiographic study is required to give a definite diagnosis of renal AV fistula. Due to its low cost, low risk and wide availability, we recommend that CD-US be the first-line imaging procedure for the evaluation of hematuria and renal cystic lesion as well as for followup for renal AV fistula.

Color Doppler Ultrasound Imaging of Primary Optic Nerve Sheath Meningioma

A 72-year-old woman presented with a history of progressive blurred vision of the left eye for more than 10 years and left proptosis for about 3 years. Her best-corrected visual acuity was 20/20 in the right eye and 20/200 in the left eye. Examination of the left fundus revealed temporal pallor of the optic disc and abnormal retinal vascular architecture. A retrobulbar intraconal lesion was seen on magnetic resonance imaging (MRI), which displaced the optic nerve upward and laterally to the left. Color Doppler flow imaging showed a globular, retrobulbar solid mass with the high-blood-flow hemodynamics of a tumor, compared to the low-blood-flow hemodynamics of normal orbital tissue. The tumor was partially excised and the immunohistopathologic diagnosis was meningothelial meningioma. The proptosis improved after surgery, but the corrected visual acuity remained the same in the first year of postoperative follow-up.

Large Placental Chorioangioma as a Cause of Sudden Intrauterine Fetal Death

A giant placental chorioangioma was diagnosed in a fetus at 22 weeks of gestation by prenatal ultrasound screening and color Doppler imaging. Although no signs of fetal hydrops and cardiac decompensation were observed, the situation of the fetus deteriorated rapidly and in utero fetal death occurred at 26 weeks, attributed to bleeding from ruptured sinusoids within the tumor. Prenatal diagnosis of chorioangioma and treatment modalities are discussed.

Effect of sildenafil on ocular haemodynamics.

To study the effect of sildenafil, which is an effective agent for the treatment of erectile dysfunction, on ocular haemodynamics. In this prospective study we examined the effect of a single oral dose of 50 mg sildenafil (Viagra) in a group of healthy young male volunteers, by using colour Doppler ultrasound imaging to measure haemodynamic variables in the central retinal artery (CRA), short temporal posterior ciliary artery (STPCA) and ophthalmic artery (OA). The following examinations were performed on both eyes immediately before and 1 h after a single oral dose of 50 mg sildenafil: visual acuity, intraocular pressure (IOP), colour vision, anterior segment, fundus appearance, resting heart rate, blood pressure and colour Doppler measurements. After sildenafil administration, peak systolic velocity, mean velocity and end-diastolic velocity significantly increased in the OA of both eyes. All Dopper indices remained non-significant for the CRA and STPCA of both eyes. Sildenafil did not cause any significant change in IOP, colour vision, visual acuity, systolic blood pressure or diastolic blood pressure. However, heart rate measurements increased significantly after sildenafil administration compared with baseline (p = 0.003). The increased flow velocity in the ophthalmic artery seems to be due to a vasodilator effect of sildenafil.

The role of fetal surgery in life threatening anomalies.

The development and evolution of fetal surgery and the recognition of the fetus as a patient came from two sources. First, were those obstetricians and perinatologists who detected life threatening anomalies before birth, and re-described a hidden mortality arising from death in utero. Ultrasonography, color Doppler ultrasound and ultrafast fetal magnetic resonance imaging have since enhanced the accuracy of prenatal evaluation. Second, were those pediatricians responsible for treating newborn infants with extremely serious problems, and that appeared untreatable, although, it was believed that they could have been treated at an earlier stage of development. After the natural history of several correctable lesions had been determined and the selection criteria for intervention developed, fetal surgery emerged as a means of improving the overall morbidity and mortality rates.

A comparative study of betaxolol and dorzolamide effect on ocular circulation in normal-tension glaucoma patients

ObjectiveTo determine whether dosages of a selective β-blocking agent (betaxolol) and a topical carbonic anhydrase inhibitor (dorzolamide), sufficient to significantly lower intraocular pressure (IOP), have similar or disparate impact on the retinal and retrobulbar circulation. DesignCounterbalanced crossover, with open-label use of medications. ParticipantsNine persons with normal-tension glaucoma (NTG). InterventionAfter a 3-week drug washout, NTG patients were studied after 1 month of treatment with either dorzolamide or betaxolol, with determinations of IOP and retinal and retrobulbar hemodynamics. Main outcome measuresAt baseline and after treatment with each drug, retinal arteriovenous passage time was determined by scanning laser ophthalmoscopy after fluorescein dye injection, and flow velocities in the central retinal and ophthalmic arteries were measured with color Doppler ultrasonography imaging. ResultsBetaxolol and dorzolamide each lowered IOP significantly, with these changes apparent and maximal after 2 weeks (each P < 0.05). In contrast, dorzolamide (but not betaxolol) accelerated arteriovenous passage of fluorescein dye in the inferior temporal quadrant of the retina (P < 0.05). Neither drug affected arteriovenous passage in the superotemporal retina or any aspect of central retinal or ophthalmic artery flow velocity after either 2 or 4 weeks. ConclusionsAlthough both dorzolamide and betaxolol are effective ocular hypotensive agents and their topical instillation leaves retrobulbar hemodynamics unaltered, dorzolamide alone accelerates inferotemporal retinal dye transit.

A review of ocular blood flow measurement techniques

Several major eye diseases may be characterized by deficits in ocular blood flow. Maintaining adequate nutrient delivery to the choroid, retina, and optic nerve head may prevent cellular damage and loss, complementing efforts to provide neuroprotection. The ability to quantify deficits in ocular blood flow has increased in recent years with the introduction of several new techniques. 1) Scanning laser ophthalmoscopic fluorescein angiography allows the measurement of bulk retinal flow and macular capillary transit rates. 2) Scanning laser ophthalmoscopic indocyanine green angiography measures choroidal perfusion in selected areas near the optic nerve head and macula. 3) Confocal scanning laser Doppler flowmetry permits quantitation of retinal capillary perfusion. 4)Color Doppler ultrasound imaging measures flow velocities in the ophthalmic, central retinal, and short posterior ciliary arteries. While these techniques represent a major advance, significant issues regarding blood flow and ocular disease remain. First, the hemodynamic characteristics of the disease state need further definition. Second, the blood flow effects of current and future treatments must be established. Third, improvements in ocular blood flow techniques are required, both to increase anatomic precision and to allow non-invasive measurements during times of potential ischemic risk such as sleep. These developments could enhance prevention, diagnosis, and treatment of several major eye diseases.

Application of B-mode and color Doppler ultrasound imaging to neurophysiological experiments using monkeys

Application of B-mode and color Doppler ultrasound imaging to neurophysiological experiments using monkeys

Open fetal surgery for life-threatening fetal malformations

After more than two decades of experimental and clinical work, fetal surgery has become an accepted treatment modality for selected fetuses with life-threatening anomalies. Color Doppler ultrasound and ultrafast fetal magnetic resonance imaging have enhanced the accuracy of prenatal evaluation traditionally made by ultrasound alone. Fetal lung masses associated with hydrops are nearly 100% fatal. These lesions can be resected in utero if they are predominantly solid or multicystic. Thoracoamniotic shunting may be effective in the setting of a single large predominant cyst. Fetuses diagnosed with left congenital diaphragmatic hernia before 26 weeks' gestation with liver herniation and a sonographic right lung to head circumference ratio (LHR) of less than one may benefit from fetal tracheal occlusion. Fetal sacrococcygeal teratoma complicated with placentomegaly, hydrops, or progressive high output heart failure may benefit from in utero resection of the tumor. Although preterm labor still remains the Achilles heel of open fetal surgery, effective tocolysis may, in the future, expand the scope of fetal surgery.

Clinical and Imaging Features of Testicular Torsion: Role of Ultrasound: Review

The early and accurate diagnosis of testicular torsion remains a clinical challenge. The implications of a missed diagnosis have emphasized the need for a non-invasive test for confirming testicular ischaemia; a problem highlighted by difficulties in establishing the diagnosis clinically. Understandably, the advent of colour Doppler ultrasound (CDUS) (and subsequently ‘power’ Doppler and microbubble ultrasound contrast), has been greeted with enthusiasm. However, as in other fields of medicine, a policy placing sole reliance on a single technique is likely to be flawed. This review will critically evaluate the role of CDUS and other imaging modalities in the diagnosis of testicular torsion.Sidhu, P. S. (1999) Clinical Radiology54 , 343–352.