Ultrasound Doppler Sonography Research Articles

Boundary Condition Options for Carotid Bifurcation Analysis, Using Doppler Velocity Measurements

The Common Carotid Artery plays a vital role in supplying the brain, and its bifurcation is susceptible to vascular diseases. It is often analyzed using computational fluid dynamics (CFD) simulations, but it is challenging to prescribe boundary conditions that approach patient-specific flow conditions. We examined six boundary condition (BC) groups to determine the most accurate flow conditions aligning with available measured data. We conducted CFD simulations on a stenotic carotid bifurcation, using patient-specific Doppler ultrasound sonography velocity measurements at the inlet and both outlets. Three BC methods used defined inlet flow rate and either constant pressure (Basic), Windkessel model, or constant flow ratio (Murray) at the outlets. Three other methods were defined with flow rates at two boundaries and constant pressure at the third one. Defining two boundary flow rates shows the closest results to physiologically valid data. However, the difficult Doppler measurements on the outlet branches can inaccurately amplify velocity amplitudes and may detect a false flow direction. Therefore, cross-sectional corrections were implemented to fit the outlet and inlet flow rates, while keeping the measured velocity histories.Our results show that the Murray and Basic methods, while easily available, exclude carotid-specific flow conditions by disregarding downstream flow resistances. We conclude that a Windkessel-method can produce the most accurate results without forcing outflow conditions. However, usually unavailable measurements are necessary for its application. Simulations with outlet-defined volume flow can also produce physiologically valid solutions but require the application of cross-sectional geometry correction.

Point stimulation with essential oils in complex effect on lumbosacral dorsopathies

The work is devoted to the analysis of the mechanisms and evaluation of the effectiveness of various methods of topical use of essential oils in dorsopathies.Materials and methods. 90 patients (38 women and 52 men aged 40 to 75 years with exacerbation of dorsopathy at the lumbosacral level) were under observation. Along with neurological, psychological (using questionnaire methods) and electrophysiological analysis was performed, including thermography, rheovasography and ultrasound Doppler sonography of the vessels of the legs and feet. Three groups of 30 patients each were formed, in which standard treatment was performed. In addition to this, a mixture of essential oils was used in the first two groups. In the 1st group, with the use of this composition, massage of the lumbosacral zone was performed, in the 2nd group, the method of biopuncture was used, i. e., applying minimal doses of the mixture to the projection of reflexology points. In the 3rd control group, sesame oil was applied to the point area as a placebo.Results. In the course of the work, the effectiveness of both types of true use of essential oils was confirmed, significantly exceeding the control indicators in this regard. However, stable analgesia was achieved in the 2nd group significantly earlier than in the 1st: in a proportion close to this, the final intensity of pain sensations also decreased. On the other hand, in both groups of oil use, there was a comparable improvement in zonal vascular provision, confirmed electrophysiologically.Conclusions. During the follow-up evaluation, recurrences of dorsopathy in the control group were noted in a third of patients, whereas in the case of the use of essential oils, there were comparably fewer doses. Nevertheless, in these groups there are differences in the severity of recurring algias: in the 2nd group they increased slightly, while in others they increased to a greater extent. In addition, the data of rheovasograms testified in favor of greater stability of the results in the 2nd group. These differences can be explained by the cumulative effect inherent in the methods of reflexology and, in particular, biopuncture with essential oils.

Кардиальная дисфункция у плода: влияние на исходы в перинатальном периоде у недоношенных детей

Objective. To study the importance of fetal cardiac dysfunction in the genesis of perinatal brain damage in premature newborns. Patients and methods. A prospective cohort comparative study included 59 preterm infants with gestational age from 26 to 32 weeks and body weight from 590 to 1990. Newborns were divided into 2 groups at the 1st month of life: the main group (n = 38), which included children with structural brain lesions, and the control group (n = 21) with favorable neurological outcomes. There were no statistically significant differences in either body weight or gestational age between the groups. At the antenatal stage, all underwent ultrasound doppler sonography of uteroplacental blood flow, and the cerebral-placental ratio was calculated. The following markers were determined at the 1st day of postnatal life: levels of lactate, cerebral natriuretic propeptide and soluble type 2 tumor suppressor in the umbilical cord blood of a newborn (enzyme-linked immunosorbent assay); neurosonography of the brain with the determination of blood flow and doppler echocardiography. Neurological outcomes were assessed after 1 month of life after the control neurosonography of brain. The data are presented in the form of median, maximum and minimum values – Me [min; max]. The obtained data were processed using the Statistica 6.1 program. The Mann–Whitney and Fisher χ2 criteria with the Yeats correction were calculated. The differences were considered significant at p equal to 0.05. Results. The pulsation index in the umbilical cord artery was significantly higher (1.270 [1.120; 1.320] versus 0.984 [0.798; 1.120]) in the fetuses of the main group, Its values indicating severe disorders of fetal-placental hemodynamics were more often recorded (in 15–39.5% cases versus 4–19.1%). The significant decrease in the cerebroplacental ratio was significantly more often recorded (in 18–47.4% cases versus 2–9.5%) in the same group. The levels of lactate (3.6 [2.1; 5.2] versus 2.25 [1.3; 3.05] mmol/L) and cerebral natriuretic propeptide (243.2 [84.17; 1385] versus 111.6 [64.8; 2903] pg/ml, respectively) were significantly elevated in the umbilical cord blood, in newborns of the main group. The newborns of the main group had significantly lower levels of systolic, diastolic and mean blood pressure, at the first hours of life. They also had a reduced level of blood flow in the superior vena cava (Me = 65 ml/kg/min; 9 (23.7%) children had a periventricular leukomalacia, 18 (47.4%) – intraventricular hemorrhages of the II–III degree, and 2 (5.3%) had a stroke. Conclusion. It is very important to pay attention of pediatricians-neonatologists to the antenatal period. Treating the fetus as a patient, early assessment of hemodynamics and timely diagnosis of fetal cardiac dysfunction and other developmental abnormalities will reduce the incidence of disabling perinatal diseases and the level of perinatal mortality. Key words: antenatal diagnosis, umbilical cord blood lactate, prematurity, perinatal brain damage, placental insufficiency, fetal cardiac dysfunction

Historical Steps in Establishing Diagnostic Criteria for Grading Stenosis of Brain Supplying Arteries: A Litmus Test for Clinical Usefulness

This publication describes the development of the diagnosis of stenosing diseases of brain-supplying arteries using ultrasound Doppler sonography, based on the personal experience of the author. It starts with the search test of flow alteration at the ophthalmic arteries as evidence of upstream obstruction and ends with the examination of extra- and intracranial arteries using Color Duplex technology. The advantage of ultrasound diagnostics is the good morphological description of the wall changes together with the assessment of hemodynamics. A meaningful assessment of the degree of stenosis requires knowledge of existing collateral circulation. The clinical utility of this method is in constant flux, depending on new therapeutic methods.

Therapy of moderate cognitive impairment and asthenia in patients with cerebrovascular pathology: results of a prospective observational study

Obtaining additional data on the efficacy and safety of the drug Prospekta in the treatment of moderate cognitive impairment (MCI) and asthenia in patients with cerebrovascular disease (CVD). A prospective observational study in more than 40 Russian cities enrolled 232 patients (mean age 61.5±10.0 years) with mild cognitive impairment (MCI), asthenia on ongoing basic nootropic therapy. The presence of MCI was confirmed by the Montreal Cognitive Assessment Scale (MoCA), asthenia - by 10-point Visual Analog Scale (VAS). All patients were prescribed the nootropic medication Prospekta 2 tablets 2 times a day for 8 weeks in addition to the therapy they received. Ultrasound Doppler sonography of the main arteries of the head and magnetic resonance imaging (MRI) of the brain were also assessed. At the end of treatment, the Clinical Global Impression Efficacy Index (CGI-EI) was assessed and the safety of the treatment was evaluated. The baseline severity of cognitive impairment according to the MoCA scale was 21.6 points, severity of asthenia according to the VAS was 6.3 points. According to Doppler flowmetry findings, hemodynamically significant stenosis was revealed in 105 (49.3%) patients, and narrowing of the main vessels without changes in hemodynamic parameters was revealed in 108 (50.7%) patients. According to MRI results, single vascular lesions in the brain matter were detected in 102 (44.0%) patients. The medications with nootropic effect were administered to 144 (62.1%) patients. A positive therapeutic response as improvement of cognitive functions was seen in 93.3% of patients after 8 weeks of taking Prospekta, including 39.4% of patients who had cognitive functions restored to the normal level. No side effects were registered during the observational study. The nootropic medication Prospekta is effective and safe in treatment of MCI in patients with asthenia with CVD, and improves cognitive function in patients with asthenia with CVD, both in monotherapy and in combination with other nootropic agents.

Особливості ренального кровотоку при гострому пошкодженні нирок у недоношених новонароджених дітей з гемодинамічно значущою відкритою артеріальною протокою

Hemodynamically significant patent ductus arteriosus (HSPDA) in premature infants leads to renal hypoperfusion due to the phenomenon of «stealing» of the systemic circulation, which can contribute to the development of acute kidney injury (AKI). The use of ultrasound Doppler sonography of the renal vessels can be effective in assessing renal blood flow and in the early diagnosis of acute renal failure. Purpose — to assess the prognostic significance of the state of renal blood flow in the first day of life in premature infants with HSPDA in the early diagnosis of AKI. Materials and methods. We examined 40 preterm infants (gestational age 29–36 weeks) with HSPDA. Distribution of the examined patients: the group with AKI — 23 children, the group without AKI — 17 children. The observation period was 10 days. The patients underwent echocardiography with Doppler analysis using a broadband microconvex probe with a frequency of 5–8 MHz (TOSHIBA Nemso XG) at 5–11 hours of life. Color Doppler ultrasound scanning of renal vessels was performed on the first, third and tenth days of life. The parameters of blood flow in the main renal and interlobar renal arteries were studied: peak systolic velocity (PSV) and end diastolic velocity (EDV) of blood flow, resistance index (RI). Diagnosis and stratification of AKI severity met the KDIGO neonatal modification criteria. Results. On the third to fifth day of life, AKI was diagnosed in 23 (57.5%) children, but already in the first day of life, compared with patients without AKI, a significant decrease in PSV parameters of blood flow in the main renal artery was noted (20.6±5.87 cm/sec versus 25.4±6.17 cm/sec in children without AKI, p<0.02). In addition, the main changes in the first day of life in patients with AKI were revealed at the level of the interlobar renal artery, namely: a decrease in PSV blood flow (11.10±3.329 cm/sec versus 18.48±3.014 cm/sec in children without AKI, p<0.001) and EDV of blood flow (2.83±2.063 cm/sec versus 6.16±2.447 cm/sec in children without AKI, p<0.001), increased RI (0.758±0.137 versus 0.666±0.1216 in children without AKI, p<0.02). On the third day of life at AKI, there was a disorder in the parameters of blood flow in the interlobaric renal artery, the value of which on the tenth day of life did not differ from the parameters of children without AKI. Conclusions. In premature infants with HSPDA, who were diagnosed with AKI on the third to fifth day of life, in the first day of life, there is a decrease in PSV blood flow parameters in the main renal artery, changes in blood flow in the interlobar renal artery, namely: a decrease in PSV and EDV blood flow, an increase in RI. Thus, the assessment of the state of blood flow in the interlobar renal artery on the first day of life in premature infants with HSPDA is of diagnostic value for the timely determination of the risk group for AKI. The research was carried out in accordance with the principles of the Helsinki declaration. The study protocol was approved by the Local ethics committee of all participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interest was declared by the authors. Key words: premature infants, patent ductus arteriosus, renal blood flow, acute kidney injury.

Значение гемодинамических расстройств в сосудах сетчатки в течении идиопатических ретиноваскулитов

Relevance of this pathology is since both eyes are affected, characterized by a sluggish, relapsing course, affecting children and adolescents. Since this pathology is based on aseptic inflammation of the vascular wall in the retina of autoimmune origin, leading to hemodynamic disorders, our goal is to study the significance of hemodynamic disorders in various ocular fundus changes in patients with idiopathic retinovasculitis. Special research methods have been performed: autoperimetry, biomicroscopy of the anterior segment and internal structures of the eye, direct and reverse ophthalmoscopy, OCT of optic disc and yellow spot, autofluorescence vascular OCT with central retinal artery and central retinal vein calibrometry, ultrasound Doppler sonography of retinal vessels. Blood tests for antibodies of viral, bacterial and infectious diseases, immune status testing. Results: greater increase in the linear velocity of blood flow in the arteria ophthalmica, central retinal artery and central retinal vein and superior orbital vein in patients with neuroretinopathy: respectively: 64.86±0.46 cm/sec, 62.0±1.03 cm/sec (P<0.01), 21.0±0.7 cm/sec, 20.0±0.76 cm/sec (P<0.05). Angiospasm phenomena prevailed in all patients — RI=0.83±0.010; RI=0.8±0.014 (P<0.05). There were detected venous discirculation in the venous system with increase of linear velocity of blood flow up to 13,5±0,7 cm/sec and 15,0±0,74 cm/sec (P<0,05). In patients with maculodystrophy it was 10.8±0.82 cm/sec and 12.6±0.58 cm/sec (P<0.05). The frequency of hemodynamic disturbances prevailed in neuroretinopathies — 53.1% in arteria ophthalmica, 50% in central retinal artery, 50% in central retinal vein and 39% in superior orbital vein. Conclusion: The major disorders of microcirculation in the retinal arterio-venous system were detected in patients with neuroretinopathies. Microcirculatory disorders detected by ultrasound in patients with idiopathic retinovasculitis allow to determine the tactics, prognosis, and effectiveness of treatment.

Vascular sound visualization system is useful for monitoring and surveillance of vascular access.

Vascular access (VA) is a lifeline for maintenance hemodialysis patients. Monitoring and surveillance of VA, therefore, play an important role for maintaining VA patency. Surveillance needs special apparatus to estimate the VA function, while, monitoring including physical examination does not usually need such devices but highly skill-dependent and qualitative. We report the clinical utility in monitoring and surveillance of VA using a newly developed electronic stethoscope and vascular sound visualization application. One hundred eight patients participated in the study. The vascular sounds were collected using the electronic stethoscope, converted into digital data, sent wirelessly to a personal computer, and then calculated. The units for the calculated intensity of the vascular sound were decibel [dB]. The intensity, however, was normalized as INDEX values ranging from 0 to 99 for practical use. Correlation between INDEX and the mean flow volume (mFV) and resistance index (RI) of brachial artery measured by Doppler ultrasound sonography were examined for VA surveillance. INDEX was continually measured at each dialysis session in ten patients who underwent the angioplasty for VA monitoring. INDEX significantly correlated with the mFV (coefficient of correlation value = 0.68, p < 0.001) and RI (coefficient of correlation value = -0.51, p < 0.001) of brachial artery. Using the calculated cut-off values, the accuracy of INDEX for the diagnosis of AVF dysfunction ranged from 66% to 82%. INDEX attained the peak just after the angioplasty of culprit lesions and gradually decreased from one patient to another. These results suggest that vascular sound visualization system can be useful in VA monitoring and surveillance for detecting and predicting the access stenosis.

Factors Raising Serum Ammonia Level During Lenvatinib Treatment of Patients With Hepatocellular Carcinoma.

Hepatic encephalopathy is an adverse event resulting from lenvatinib use in patients with hepatocellular carcinoma (HCC). We analyzed the influence of lenvatinib on portal venous flow velocity (PVV) and serum ammonia concentration. Eleven patients with unresectable HCC were enrolled, including three with modified albumin-bilirubin (mALBI) grade 1, three with grade 2a, and five with grade 2b. PVV was measured by Doppler ultrasound sonography before and on day 2 of administration. Out of 11 patients, one developed hepatic encephalopathy. PVV was reduced in 10 patients, and the change from baseline was significantly correlated with lenvatinib dosage. The increase in serum ammonia concentration was affected by lenvatinib dose and baseline hepatic function as a threshold between mALBI grade 2a and 2b statistically. There was no correlation between changes in PVV and serum ammonia concentration. Lenvatinib might directly disturb hepatocyte metabolism to result in increased serum ammonia concentration.

P6375Correlation between cytokine profile and ultrasonic characteristics of atherosclerotic plaques in patients with essential hypertension

Abstract Objective To study the association of serum cytokine concentrations (tumor necrosis factor-alpha (TNF-a) and interleukin-10 (IL-10)) with ultrasonic characteristics of atherosclerotic plaque and signs of its instability. Materials and methods We examined 166 patients (mean age 56.3±6.1 years). We used the generally accepted classification of Gray-Weale AC et al.(1988) to describe the structural characteristics of atherosclerotic plaque (ASP) and to determine local hemodynamic defects. There were 3 groups of patients. The 1st group included 48 patients with homogeneous hyperechoic plaques, the 2nd group included 56 patients with predominantly hyperechoic ASP (more than 50% of sites), the 3rd group included 13 patients with anechoic, low ultrasound density of ASP or with predominantly hypoechoic average density ASP (more than 50% of sites with average density). The control group consisted of 39 patients with essential hypertension (EH) without atherosclerotic lesions of the carotid arteries. All patients were subjected to general clinical examinations (measuring height, weight, waist, systolic and diastolic blood pressure, calculating body mass index), laboratory tests (lipid profile, fasting glucose, creatinine with glomerular filtration rate (eGFR), fibrinogen, TNF-a and IL-10). Mass determination of TNF-a and IL-10 was carried out by the method of enzyme-linked immunosorbent assay and ultrasound doppler sonography of the carotid arteries, common carotid artery scanned in longitudinal section using a wideband linear sensor with a frequency of 3–11 MHz, the image was synchronized with the R wave on the ECG). Results Patients of the 1st (7,26±0,64 pg/ml) and 2nd groups (8,93±0,98 pg/ml) who do not have ultrasonic signs of ASP instability TNF-a was significantly lower than in patients of the 3rd group (10,51±2,23 pg/ml, p&lt;0,001) with ultrasound signs of ASP instability. Similar results were obtained in terms of the level of IL-10. The level of IL-10 in patients of the 1st and 2nd groups, having reached 14,7±3,5 pg/ml and 14,4±2,7 pg/ml, was significantly lower in comparison with patients of the 3rd group (17,1±5,3 pg/ml, p&lt;0,025 and p&lt;0,017, respectively). The logistic regression analysis showed that the independent factors associated with the presence of ultrasonic signs of ASP instability in patients with EH are: age (HR-1,20; 95% CI 1,03–1,38; p&lt;0,02), concentration of triglycerides (HR-4,05; 95% CI 1,90–8,64; p&lt;0,001) and TNF-a (HR-2,72; 95% CI 1,44–5,15; p&lt;0,02). The influence of other factors, including IL-10, on the instability of ASP was less significant (p&gt;0,05). Further statistical analysis showed that in patients with level of TNF-a more than 10 pg/ml, the risk of detecting an unstable ASP increased almost in 7 times (HR 6,81; 95% CI 2,17–21,6). Conclusions Increasing the concentration of tumor necrosis factor-alpha above 10 pg/ml is an independent risk factor for unstable atherosclerotic plaques in patients with essential hypertension

Incidence of Venous Thromboembolism Following Laparoscopic Surgery for Gastrointestinal Cancer: A Single-Center, Prospective Cohort Study.

The occurrence of venous thromboembolism (VTE), manifesting as deep vein thrombosis or pulmonary embolism, after gastric and colorectal cancer surgery remains poorly characterized. The purpose of this study was to investigate the incidence of VTE following laparoscopic surgery in Japanese patients with gastric and colorectal cancer and identify the associated risk factors. We prospectively analyzed VTE events after laparoscopic surgery for gastric and colorectal cancer from April 2012 to March 2013 in our institute. Deep vein thrombosis was diagnosed with Doppler ultrasound sonography of the lower limb. Thromboprophylaxis, graduated compression stockings, and intermittent pneumatic compression were used in all patients. Fondaparinux sodium was used in several patients. We examined all patients' plasma D-dimer levels throughout the perioperative period. In total, 101 patients were enrolled in this study; 71 who underwent laparoscopic surgery for gastrointestinal cancer were finally analyzed. Thirteen patients (18.3 %) developed asymptomatic VTE. There were no relationships between the development of VTE and perioperative factors such as cardiovascular disease, operation time, blood loss, postoperative complications, and fondaparinux administration. Neoadjuvant treatment (chemotherapy or chemoradiotherapy) was significantly associated with VTE (p < 0.05). Plasma D-dimer levels were higher 7 days after surgery in patients with than without VTE, although the levels remained high after surgery in all patients. The incidence of VTE among Japanese patients who underwent laparoscopic surgery for gastrointestinal cancer was not low. In particular, clinicians should consider the higher risk of VTE in patients undergoing neoadjuvant therapy.

Differential diagnosis of hemangiomas and other orbital masses

Aim. To determine the differential diagnostic scintigraphic signs of hemangiomas and malignant tumors of the orbit.Methods. Comprehensive survey of 35 patients with orbital masses included a standard eye examination, ultrasound Doppler sonography, computed tomography or magnetic resonance imaging, scintigraphy using in vivo labeled 99mTs erythrocytes, and morphological study.Results. Scintigraphic studies using in vivo labeled 99mTs erythrocytes in 18 patients with hemangioma of the orbit, no accumulation of radiotracer in the dynamic phase of the study was observed. On the subsequent delayed planar scintigraphy and single-photon emission computerized tomography, intense delayed hyperfixation of in vivo labeled 99mTs erythrocytes in the lesion was revealed. In 8 patients with malignant orbital tumors (adenocarcinoma of the lacrimal gland - 4, osteogenic sarcoma - 1, olfactory neuroblastoma - 1, metastasis of renal cancer in orbit - 1) there was an intense accumulation of labeled erythrocytes in the projection of the affected area in all phases of the nuclear study. In patients with adenoma of the lacrimal gland, cranioorbital meningioma, orbital pseudo tumor, as well as in 1 patient with lacrimal gland adenocarcinoma, no pathological accumulation of in vivo labeled 99mTs erythrocytes in the lesion was observed at any stage of the study.Conclusion. According to the results of scintigraphic studies: (1) patients with orbital hemangioma had no accumulation of in vivo 99mTs labeled red blood cells in the vascular (dynamic) phase of the study and had hyperfixation of radiotracer in delayed planar scintigraphy and single-photon emission computerized tomography; (2) intensive accumulation of labeled 99mTs erythrocytes in tumor vascular (dynamic) phase of the study as well as in delayed planar scintigraphy and single-photon emission computerized tomography was characteristic of malignant neoplasms with hypervascularization.

Ultrasound and contrast enhanced ultrasound sonography evaluation of intestinal acute graft-vs-host disease

SUMMARY Intestinal acute graft-vs-host disease (I-GVHD) is a life-threatening complication after allografting. Non-invasive bedside procedures to evaluate extension and treatment response are still lacking. Standard ultrasound sonography (US) detects bowel wall thickening (BWT) in I-GVHD and helps to identify its extension (single or multiple sites at once). Color doppler US detects blood flow at arterioles level. Contrast-enhanced ultrasound sonography (CEUS) can detect microcirculation changes (MVC) of the bowel wall at capillary level, real time, and even bedside. CEUS allows evaluating, with dedicated software, quantitatively wash-in and washout curves of blood flowing through the thickened bowel wall, giving time intensity curves, which help to monitor treatment response as for Chron’s disease. Patients with I-GVHD with clinical relevant improvement may still have quiescent active disease. CEUS allows identifying, qualitatively and quantitatively, patients with I-GVHD with clinical improvement but with still active disease.

Pediatric Laparoendoscopic Single-site Partial Nephrectomy: Initial Report

We present a case of transumbilical laparoendoscopic single-site surgery (LESS) for partial nephrectomy in a child. On May 22, 2009, we performed LESS partial nephrectomy on a 7-year-old girl with a 3.5-cm renal mass. The surgery was performed using a homemade single-port device inserted through a single 3-cm umbilical incision. LESS partial nephrectomy was performed with hilar clamping and suturing of the renal defect. The duration of the operation was 210 minutes, and the warm ischemic time was 42 minutes. The suturing required 35 minutes, and the estimated blood loss was 10 mL. Histopathological analysis revealed a 3.5-cm metanephric adenoma with a clean surgical margin. The patient was discharged without intraoperative or postoperative complications. On follow-up, Doppler ultrasound sonography showed the kidney was normal in appearance, size, and echogenicity. Split renal function was calculated to be 47.5% for the left kidney upon dimercaptosuccinic acid renal scintigraphy. LESS partial nephrectomy was safe and feasible for removal of a renal mass in a child. Additional development of applicable instruments and refinement of the suturing technique are needed.

Doppler ultrasound sonography of the supratrochlear artery in temporal arteritis (author's transl)

The risk of ocular involvement in temporal arteritis is difficult to assess in the individual case. Using Doppler ultrasound sonography a clearly reduced flow or arrest of flow in the supratrochlear artery of the amaurotic side could be demonstrated in three patients. Attempts to compress branches of the external carotid artery caused no change of flow behaviour. Doppler sonography thus permits assessment of involvement of orbital vessels. This indicates the risk of loss of vision.

MCA Vmean and the arterial lactate-to-pyruvate ratio correlate during rhythmic handgrip

Regulation of cerebral blood flow during physiological activation including exercise remains unknown but may be related to the arterial lactate-to-pyruvate (L/P) ratio. We evaluated whether an exercise-induced increase in middle cerebral artery mean velocity (MCA Vmean) relates to the arterial L/P ratio at two plasma lactate levels. MCA Vmean was determined by ultrasound Doppler sonography at rest, during 10 min of rhythmic handgrip exercise at approximately 65% of maximal voluntary contraction force, and during 20 min of recovery in seven healthy male volunteers during control and a approximately 15 mmol/l hyperglycemic clamp. Cerebral arteriovenous differences for metabolites were obtained by brachial artery and retrograde jugular venous catheterization. Control resting arterial lactate was 0.78 +/- 0.09 mmol/l (mean +/- SE) and pyruvate 55.7 +/- 12.0 micromol/l (L/P ratio 16.4 +/- 1.0) with a corresponding MCA Vmean of 46.7 +/- 4.5 cm/s. During rhythmic handgrip the increase in MCA Vmean to 51.2 +/- 4.6 cm/s was related to the increased L/P ratio (23.8 +/- 2.5; r2 = 0.79; P < 0.01). Hyperglycemia increased arterial lactate and pyruvate to 1.9 +/- 0.2 mmol/l and 115 +/- 4 micromol/l, respectively, but it did not significantly influence the L/P ratio or MCA Vmean at rest or during exercise. Conversely, MCA Vmean did not correlate significantly, neither to the arterial lactate nor to the pyruvate concentrations. These results support that the arterial plasma L/P ratio modulates cerebral blood flow during cerebral activation independently from the plasma glucose concentration.

Enhanced cerebral CO2 reactivity during strenuous exercise in man

Light and moderate exercise elevates the regional cerebral blood flow by approximately 20% as determined by ultrasound Doppler sonography (middle cerebral artery mean flow velocity; MCA V(mean)). However, strenuous exercise, especially in the heat, appears to reduce MCA V(mean) more than can be accounted for by the reduction in the arterial CO(2) tension (P(a)CO(2)). This study evaluated whether the apparently large reduction in MCA V(mean) at the end of exhaustive exercise relates to an enhanced cerebrovascular CO(2) reactivity. The CO(2) reactivity was evaluated in six young healthy male subjects by the administration of CO(2) as well as by voluntary hypo- and hyperventilation at rest and during exercise with and without hyperthermia. At rest, P(a)CO(2) was 5.1 +/- 0.2 kPa (mean +/- SEM) and MCA V(mean) 50.7 +/- 3.8 cm s(-1) and the relationship between MCA V(mean) and P(a)CO(2 )was linear (double-log slope 1.1 +/- 0.1). However, the relationship became curvilinear during exercise (slope 1.8 +/- 0.1; P < 0.01 vs. rest) and during exercise with hyperthermia (slope 2.3 +/- 0.3; P < 0.05 vs. control exercise). Accordingly, the cerebral CO(2) reactivity increased from 30.5 +/- 2.7% kPa(-1) at rest to 61.4 +/- 10.1% kPa(-1) during exercise with hyperthermia (P < 0.05). At exhaustion P(a)CO(2) decreased 1.1+/- 0.2 kPa during exercise with hyperthermia, which, with the determined cerebral CO(2) reactivity, accounted for the 28 +/- 10% decrease in MCA V(mean). The results suggest that during exercise changes in cerebral blood flow are dominated by the arterial carbon dioxide tension.

Acupuncture using laser needles modulates brain function: first evidence from functional transcranial Doppler sonography and functional magnetic resonance imaging

Acupuncture using laser needles is a new totally painless stimulation method which has been described for the first time. This paper presents an experimental double-blind study in acupuncture research in healthy volunteers using a new optical stimulation method. We investigated 18 healthy volunteers (mean age +/- SD: 25.4 +/- 4.3 years; range: 21-30 years; 11 female, 7 male) in a randomized controlled cross-over trial using functional multidirectional transcranial ultrasound Doppler sonography (fTCD; n = 17) and performed functional magnetic resonance imaging (fMRI) in one volunteer. Stimulation of vision-related acupoints resulted in an increase of mean blood flow velocity in the posterior cerebral artery measured by fTCD [before stimulation (mean +/- SE): 42.2 +/- 2.5; during stimulation: 44.2 +/- 2.6; after stimulation: 42.3 +/- 2.4 cm/s, n.s.]. Mean blood flow velocity in the middle cerebral artery decreased insignificantly. Significant changes (p < 0.05) of brain activity were demonstrated in the occipital and frontal gyrus by fMRI. Optical stimulation using properly adjusted laser needles has the advantage that the stimulation cannot be felt by the patient (painless and no tactile stimulation) and the operator may also be unaware of whether the stimulation system is active. Therefore true double-blind studies in acupuncture research can be performed.

A Case of Pulmonary Sequestration Diagnosed by Doppler Sonography

Pulmonary Sequestration is a rare congenital malformation during embryouic development which results in a cystic mass of nonfunctioning lung tissue. A diagnosis of a pulmonary sequestration has traditionally relied upon identifying the pathological arterial vessels by arteriography, computed tomography, and magnetic resonance imaging. We reported a case of pulmonary sequestration diagnosed by Doppler sonography and subsequent CT angiography. A 21-year-old-woman admitted to hospital for an investigation of recurrent pneumonia with left lower chest pain. A doppler ultrasound sonography showed an aberrant blood supply from the descending thoracic aorta to the left lower chest lesion. The pulmonary sequestration was confirmed by the subsequent CT angiograph.

Dialyzer Blood Flow Less Affects Access Recirculation in Hemodialysis Patients with Higher Access Blood Flow.

It has been known that access recirculation is positively related to dialyzer blood flow and is negatively related to access blood flow in the vascular access in hemodialysis patients. The present study was designed to examine whether an increase in access recirculation generated by an increase in dialyzer blood flow is related to access blood flow. All patients had native end-to-side arteriovenous anastomoses at the radial site. We measured access recirculation at two different dialyzer blood flow rates (85 and 170 ml/min) using a three-needle technique. Access blood flow rates (mean 668 ml/min ranging from 493 to 1038 ml/min) were measured using Doppler ultrasound sonography. We confirmed that an increase in dialyzer blood flow rate led to an increase in access recirculation (5.4±1.1 vs. 9.9±1.9%, p<0.05), and that access recirculation was negatively related to the access blood flow rate (y=-30.78x+972.20, r=-0.79, p<0.05). We further found a negative correlation between the increase in access recirculation generated by the increase in dialyzer blood flow rate and access blood flow rate (y=-33.88x+821.57, r=-0.75, p<0.05). These results suggested that dialyzer blood flow less affects access recirculation when access blood flow is higher.