The effect of loading dose of magnesium sulfate on uterine, umbilical, and fetal middle cerebral arteries Doppler in women with severe preeclampsia: A case control study

SYNOPSIS IV MgSO4 administration in women with severe preeclampsia resulted in a decrease in umbilical artery, uterine artery, and fetal middle cerebral artery Doppler indices.

OBJECTIVE

To evaluate Doppler parameters of the umbilical artery (UmA), uterine artery (UA), and fetal middle cerebral artery (MCA) before and after MgSO4 administration in women with severe preeclampsia.

METHODS

A case control study included 100 pregnant women with severe preeclampsia. Umbilical artery, uterine artery, and fetal middle cerebral artery Doppler were measured before and 20 minutes after intravenous administration of 6 g of magnesium sulfate.

RESULTS

There was a significant difference between maternal systolic blood pressure (173.20 ± 22.72 vs. 156.60 ± 19.18), diastolic blood pressure (109.60 ± 9.14 vs. 101.90 ± 10.05), and heart rate (80.52 ± 11.52 vs. 88.48 ± 12.08) before and after administration of MgSO4 in the studied patients (p value < 0.001). There was a significant difference between umbilical artery, middle cerebral artery, and uterine artery Doppler parameters before and after administration of MgSO4 in the studied patients (p value < 0.001). There was no significant difference between umbilical artery/middle cerebral artery with regard to RI and PI. However, there was significant difference with regard to the S/D ratio (p value < 0.001). The decrease in the values of Doppler parameters before and after administration of MgSO4 was more in the middle cerebral artery than in the umbilical artery.

CONCLUSION

Intravenous administration of magnesium sulfate in pregnant women with severe preeclampsia resulted in a decrease in umbilical artery, uterine artery, and fetal middle cerebral artery Doppler indices with reduced resistance to blood flow in these vessels.

The role of contrast-enhanced ultrasound imaging in the follow-up of patients post-endovascular aneurysm repair

Endovascular aneurysm repair is a minimally invasive technique for the treatment of abdominal aortic aneurysms. Patients who undergo endovascular aneurysm repair are potentially at risk of developing problems related to the graft such as the development of endoleaks. Endoleaks can cause expansion of the aneurysmal sac, which can potentially lead to rupture. It is for this reason that lifelong surveillance of patients is required to assess the graft and the aneurysmal sac. This article discusses the role of contrast-enhanced ultrasound in the follow-up of patients post-endovascular aneurysm repair. Contrast-enhanced ultrasound is rapidly becoming a powerful, accurate and cost-effective tool to complement computed tomography in the follow-up of endovascular aneurysm repair patients. Real-time imaging of contrast filling into the arterial system means that contrast-enhanced ultrasound is an excellent problem-solving tool, particularly when assessing for the type and anatomy of endoleaks. In some instances, contrast-enhanced ultrasound can detect endoleaks when other modalities are equivocal.

[Renal hemodynamic in hydronephrosis concurrent with hepatobiliary system disorders, its dynamics in the course of treatment]

This article examines measurements of renal vascular ultrasound in 85 patients with hydronephrosis concurrent with disorders of the gallbladder and biliary tract, depending on severity and dynamics during treatment. The estimation of blood flow changes depending on applied renoprotective and hepatoprotective therapy is provided.

Vascular complications after adult living donor liver transplantation: Evaluation with ultrasonography

Living donor liver transplantation (LDLT) has been widely used to treat end-stage liver disease with improvement in surgical technology and the application of new immunosuppressants. Vascular complications after liver transplantation remain a major threat to the survival of recipients. LDLT recipients are more likely to develop vascular complications because of their complex vascular reconstruction and the slender vessels. Early diagnosis and treatment are critical for the survival of graft and recipients. As a non-invasive, cost-effective and non-radioactive method with bedside availability, conventional gray-scale and Doppler ultrasonography play important roles in identifying vascular complications in the early postoperative period and during the follow-up. Recently, with the detailed vascular tracing and perfusion visualization, contrast-enhanced ultrasound (CEUS) has significantly improved the diagnosis of postoperative vascular complications. This review focuses on the role of conventional gray-scale ultrasound, Doppler ultrasound and CEUS for early diagnosis of vascular complications after adult LDLT.

Contrast sonovenography - Is this the answer to complex deep vein thrombosis imaging?

BACKGROUND

Deep vein thrombosis (DVT) is a potentially fatal condition causing significant morbidity and mortality in the patient population. Ultrasound (USS) is the mainstay for detecting DVT. This can sometimes be difficult in hostile limbs due to factors such as large body habitus and oedema. This pilot study investigated contrast-enhanced ultrasound (CEUS) as a viable method to improve visualisation of the venous system of the lower limb.

METHODS

Patients at high risk for DVT were selected after an initial negative USS. A follow-up scan was performed 1 week later utilising standard B-mode imaging with a curvilinear 3-5 MHz transducer array. After the fundamental scan, intravenous Sonovue™ contrast was administered and visualisation of the proximal limb veins and visualisation gains in distance were mapped onto a proforma.

RESULTS

Twelve patients were selected. Visualisation was not improved in the common femoral vein (CFV) but increases in full visualisation were demonstrated in the femoral vein (FV) and popliteal vein (Pop V) from (n = 8) 67% and (n = 10) 83-100% in both veins, respectively. Significant gains in visualisation distance were observed in the posterior tibial vein (PTV) (p = 0.0005) and peroneal vein (Per V) (p = 0.02) with increased full visualisation of the Per V from (n = 3) 25% to (n = 7) 58%.

CONCLUSION

CEUS is a viable and clinically safe method for increasing visualisation of the deep venous system. It has the potential to improve visualisation of the lower limb venous system, reducing follow-up costs and diagnostic uncertainty for patients and the clinician.

Uterine lavage is efficient to recover endometrial cytology sample and does not interfere with fertility rate after artificial insemination in cows

Productivity rates directly depend on the fertility of a herd, which in turn can be influenced by many factors. Semen deposited in the female reproductive tract is foreign to the body and, in response to this invasion, produces an inflammatory reaction, which is characterized by rapid infusion of polymorphonuclear (PMN) cells. Techniques to obtain an endometrial sample are usually invasive and can mask the true inflammatory response. Ultrasound is a noninvasive technique and can contribute to the diagnosis of postartificial insemination (AI) inflammatory response in cattle. The present study was divided into two experiments. The aim of experiment 1 was to compare two methods of endometrial cytology collection, uterine cytobrush (UC) and uterine lavage (UL), and their effects on uterine hemodynamics that provide information about blood flow. The two methods were evaluated by Doppler ultrasound using the spectral and color modes. For that purpose, 19 Nellore cows were synchronized for timed AI and subjected to UC (n = 9) or UL (n = 10). The techniques were performed 4 hours after AI. The results showed that both techniques allow collection of a good quality sample and with enough PMN cells to perform counting. More PMN cells were obtained by UL than UC. There was no difference in uterine blood flow between the UC and UL groups in any of the periods evaluated (34 hours before and 4, 24, and 48 hours after collection of uterine sample). On the basis of results of experiment 1, the effect of UL on fertility was studied in experiment 2. A total of 128 Nellore cows were synchronized for TAI; 35 cows were subjected to endometrial cytology by UL 4 hours after AI, and 93 were not submitted to any procedure (control). Pregnancy diagnosis was performed by transrectal ultrasound 30 days after AI. Pregnancy rates did not differ between UL (54.29%) and control (56.99%) groups. The results of this study showed that UL allows the collection of more representative cells of the surface of the uterus than UC technique and causes no damage to the reproductive tract. Moreover, UL did not affect pregnancy rate when performed 4 hours after AI.

The short term fetal cardiovascular effects of corticosteroids used in obstetrics

Background: Corticosteroids are widely used in obstetrics due to their striking effect on perinatal morbidity and mortality of premature neonates. Despite this, relatively few studies have explored short term fetal effects of corticosteroids as measured by ultrasound. Objectives: 1) To present a literature review of short term fetal cardiovascular effects of corticosteroids 2) To describe the protocol of a current observational study (SUPER-A*STEROID) of cardiovascular effects of dexamethasone and betamethasone in the first week after their administration. This trial is nested within the A*STEROID blinded multicentre randomised controlled trial of the two steroid preparations. Findings: Existing data suggest corticosteroids have little effect on the major measured fetal blood vessels when the baseline ultrasound is normal. In the compromised fetus, where the umbilical artery end-diastolic flow is abnormal prior to maternal corticosteroids, flow is temporarily restored in approximately 50% of cases. Whether such changes are beneficial is uncertain. Very little data exist that directly compare the short-term effects of betamethasone and dexamethasone. The SUPER- A*STEROID study described will help provide this information.

Uterine blood flow evaluation in bitches suffering from cystic endometrial hyperplasia (CEH) and CEH-pyometra complex

Doppler ultrasound is a useful diagnosis tool to evaluate uterine blood flow in different canine reproductive states. The aim of this study was to describe and compare uterine blood flow in bitches suffering from cystic endometrial hyperplasia (CEH) and CEH-pyometra complex (CEH-P). Ninety diestrous bitches were clinically, hematologically, and ultrasonographically classified into four groups: (1) clinical signs, leukocytosis, CEH, and uterine luminal contents (CEH-P, n = 31); (2) asymptomatic bitches with CEH and uterine contents (CEH-C, n = 15); (3) asymptomatic bitches with CEH without uterine contents (CEH, n = 16); and (4) normal diestrous bitches (ND, n = 28). The widest cross-sectional diameter and uterine wall thickness (W) of uterine horns were measured using two-dimensional ultrasound. Peak systolic velocity and end diastolic velocity of uterine arteries were measured by Doppler ultrasound in all the bitches. Peak systolic velocity and end diastolic velocity were higher in CEH-P than in CEH-C, CEH, and ND (P < 0.01); although both parameters did not show differences among the latter three groups (P > 0.1). Conversely, resistance index (RI) reported lower values in CEH-P than that in the other three groups (P < 0.01), being ND higher (P < 0.01) than both CEH-C and CEH which did not differ between themselves (P > 0.1). When all the bitches were considered, correlation between RI and cross-sectional diameter was r = -0.69 (P < 0.01) and between RI and uterine wall thickness was r = -0.02 (P > 0.1). It is concluded that the uterine artery blood flow velocity of bitches suffering from pyometra was higher, not only from normal bitches, but also from females with endometrial hyperplasia. Furthermore, endometrial hyperplasia, accompanied or not by luminal contents, had a higher blood flow velocity than normal uterus. Hemodynamic parameters appear as useful markers to differentiate uterine pathologic conditions.

Standards of the Polish Ultrasound Society. Ultrasound examination of the portal system and hepatic vessels

Increased incidence of liver diseases, the development of liver surgery and other invasive methods for managing portal hypertension, plus an increasing number of liver transplant procedures pose more and more new challenges for ultrasonography. Ultrasonography, being an effective and clinically verified modality, has been used for several decades for diagnosing diseases of the liver, its vessels and portal hypertension. It is used for both initial and specialist diagnosis (performed in reference centers). The diagnostic value of ultrasonography largely depends on the knowledge of anatomy, physiology, pathophysiology and clinical aspects as well as on the mastering of the scanning technique. In the hands of an experienced physician, it is an accurate and highly effective diagnostic tool; it is of little use otherwise. The paper presents elements of anatomy, physiology and pathophysiology which make the portal system exceptional and the knowledge of which is crucial and indispensable for a correct examination and, above all, for the correct interpretation of results. The authors also present requirements regarding the equipment. Moreover, various technical aspects of the examination are presented and the normal morphological picture and hemodynamic parameters of healthy individuals are described. The authors discuss the most common clinical situations and rare cases during ultrasound examinations. The paper is based on the experience of the author who works in the largest center of liver diseases in Poland, and on the current literature.

Doppler ultrasound study and venous mapping in chronic venous insufficiency

Chronic venous insufficiency of the lower limbs is very prevalent. In recent decades, Doppler ultrasound has become the method of choice to study this condition, and it is considered essential when surgery is indicated. This article aims to establish a method for the examination, including venous mapping and preoperative marking. To this end, we review the venous anatomy of the lower limbs and the pathophysiology of chronic venous insufficiency and explain the basic hemodynamic concepts and the terminology required to elaborate a radiological report that will enable appropriate treatment planning and communication with other specialists. We briefly explain the CHIVA (the acronym for the French term "cure conservatrice et hémodynamique de l'insuffisance veineuse en ambulatoire"=conservative hemodynamic treatment for chronic venous insufficiency) strategy, a minimally invasive surgical strategy that aims to restore correct venous hemodynamics without resecting the saphenous vein.

[Clinical and pathomorphological features of chronic prostatitis in chemical industry workers]

During periodic screening on the chemical industry, an increased incidence of chronic prostatitis in workers at sulfuric acid section was revealed. Detailed examination has revealed features of the clinical picture of the pathological process that develops in the prostate gland of workers exposed to harmful labor conditions. Complex pathomorphologic analysis of prostate biopsies of workers with chronic abacterial prostatitis found fundamental differences of morphological manifestations observed in other forms of chronic prostatitis. They include the prevalence of dystrophic and atrophic changes of glandular components with the presence of focuses of simple and small acinar atrophy, reduction of the microvasculature vessels, progressive fibrosis of the stroma with the phenomena of periglandular and perivascular sclerosis, as a rule, in the absence of inflammatory cell infiltration. Doppler ultrasound data indicated a change in hemodynamics, accompanied by a decrease in blood flow in the prostate gland.

Reliability of Doppler Assessment of the Middle Cerebral Artery in the Near and Far Fields in Healthy and Anemic Fetuses

OBJECTIVES

The purpose of this study was to assess the reliability of the middle cerebral artery pulsatility index (PI) and peak systolic velocity (PSV) at the proximal portions of the near- and far-field vessel sites in healthy and anemic fetuses.

METHODS

The middle cerebral artery PSV and PI were prospectively assessed in 50 normal singleton pregnancies. The Doppler waveforms for the middle cerebral artery PI and the PSV were recorded independently by 2 operators at the most proximal portions of the near- and far-field sites. Data for the PSV and PI at the proximal portions of both the near- and the far-field sites were also retrospectively collected in 7 anemic fetuses.

RESULTS

No significant difference between the operators was detected for the middle cerebral artery PSV (P = .60) and PI (P = .88) measured in the conventionally used near-field proximal site in the 50 healthy fetuses. No significant difference between the proximal portions of the near- and far-field sites was detected for the PSV (P = .53) and PI (P = .23) in healthy or anemic fetuses.

CONCLUSIONS

The findings of this study suggest that the use of the far-field vessel is an acceptable alternative for measurement of the middle cerebral artery PI and PSV when investigation of the near-field vessel is technically difficult.

Choroidal thickness and retinal vascular caliber correlations with internal carotid artery Doppler variables

PURPOSE

Decreased retinal arteriolar caliber and increased retinal venular caliber have been associated with increased cardiovascular mortality. This study aimed to evaluate correlations of choroidal thickness and retinal vascular caliber measurements with internal carotid artery (ICA) Doppler ultrasound variables.

METHODS

In this cross-sectional and observational study, 43 eyes and ICAs of 43 healthy volunteers were examined. Spectral domain optical coherence tomography was used to measure subfoveal choroidal thickness (SFCT) and retinal vascular caliber. The ICA Doppler ultrasonographic parameters were diameter, flow volume, peak-systolic velocity, end-diastolic velocity, resistance index (RI), and pulsatility index (PI).

RESULTS

Negative correlations emerged between ICA RI and SFCT (p = 0.017, r = -0.36) as well as between ICA PI and retinal arteriolar caliber (p = 0.015, r = -0.37). A negative linear correlation appeared between ICA diameter and SFCT (p = 0.005, r = -0.42), although ICA diameter and flow volume showed no association with retinal vessel caliber (p > 0.05).

CONCLUSIONS

Choroidal thickness is negatively correlated with ICA diameter and ICA RI, while retinal arteriolar caliber is inversely related with ICA PI in normal volunteers.

Detection of Right-to-Left Cardiac Shunt in the Absence of Transcranial Acoustic Bone

PURPOSE

Paradoxical thrombotic embolism via right-to-left cardiac shunt (RLS) is a risk factor of cryptogenic ischemic stroke. Transtemporal Doppler (TTD) is a valid method used in the detection of patent foramen ovale (PFO). Temporal acoustic bone windows are missing with increasing age and in some younger subjects. We studied prospectively whether Doppler ultrasound of the cervical arteries (submandibular internal carotid artery [ICA] and vertebral artery [VA]) is an alternative, when compared to TTD, in the detection and quantification of PFO.

MATERIAL AND METHODS

A total of 94 patients with sufficient temporal bone windows suffering from recent ischemic stroke underwent TTD and ICA (n = 51) or TTD and VA (n = 43). After injection of microbubbles, the numbers of artificial high-intensity signals (HITS) were recorded at rest and after Valsalva maneuver.

RESULTS

For 47 patients in the ICA group, an RLS was found at rest in 23 patients and after Valsalva in 28 patients. At rest, sensitivity was 100%, specificity 96%, positive predictive value (ppv) 95.6%, and negative predictive value (npv) 100%. After Valsalva, sensitivity was 100%, specificity 95%, ppv 96.4%, npv 100%. For 43 patients in the VA group an RLS was found at rest in 14 patients and after Valsalva in 19 patients. At rest, sensitivity was 71.4%, specificity 100%, ppv 100%, and npv 87.8%. After Valsalva, 94.4%, 96%, 94.4%, and 96%, respectively. Pearson's correlations of the number of HITS between TTD and ICA and between TTD and VA were highly significant.

CONCLUSIONS

When transcranial acoustic bone windows are missing, Doppler ultrasound of the cervical submandibular ICA and VAs are valid screening methods to detect RLS due to a PFO.

Doppler ultrasound and calcification score: improving vascular access surveillance

AIM

Vascular access (VA) dysfunction limits hemodialysis delivery, which increases morbidity and mortality. The most com mon cause of VA failure is thrombosis, due to flow limiting stenosis resulting from neointimal hyperplasia. This occurs not only due to hemodynamic factors but also by systemic ones related to vascular atherosclerosis, inflammation and calcification, which has developed a simple vascular calcification score (SVCS) predictor of vascular calcification and arterial stiffness. The NKF-K/DOQ recommends several diagnostic procedures for VA surveillance. Blood access flow (Qa) has predictive power for the detection of stenosis. Our aim was to evaluate the role of systemic factors, especially SCVS, on Qa.

MATERIAL AND METHODS

Transversal study in 50 patients. Qa value was obtained with Blood Temperature Monitor and Doppler method. Pearson coefficient evaluated correlation between them. Clinical, lab and radiological variables were recorded and non-parametric tests evaluated how both Qa varied with them.

RESULTS

Pearson's corelation between DU-Qa and TD-Qa was 0.851 (p-value <0.001). DU-Qa varied significantly with age (p = 0.012), VA type (p = 0.021), SCVS (p = 0.030), intra-access arterial pressure (p = 0.015) and time on dialysis (p = 0.002). BTM-Qa varied significantly with diabetes status (p = 0.027), age (p = 0.017), first VA status (p = 0.036), intra-access arterial pressure (p = 0.028) and dialysis time (p = 0.001). Nevertheless, gender, hypertensive status and analitical parameters did not change the flow values.

CONCLUSION

Higher SVCS was associated only with lower DU-Qas, giving this method an advantage towards the indirect one. Additionally, a simple method like SVCS may be used to guide new surveillance recommendations accordingly to risk stratification.

Reversed portal flow: Clinical influence on the long-term outcomes in cirrhosis

AIM: To elucidate the natural history and the longitudinal outcomes in cirrhotic patients with non-forward portal flow (NFPF).

METHODS: The present retrospective study consisted of 222 cirrhotic patients (120 males and 102 females; age, 61.7 ± 11.1 years). The portal hemodynamics were evaluated at baseline and during the observation period using both pulsed and color Doppler ultrasonography. The diameter (mm), flow direction, mean flow velocity (cm/s), and mean flow volume (mL/min) were assessed at the portal trunk, the splenic vein, the superior mesenteric vein, and the collateral vessels. The average values from 2 to 4 measurements were used for the data analysis. The portal flow direction was defined as follows: forward portal flow (FPF) for continuous hepatopetal flow; bidirectional flow for to-and-fro flow; and reversed flow for continuous hepatofugal flow. The bidirectional flow and the reversed flow were classified as NFPF in this study. The clinical findings and prognosis were compared between the patients with FPF and those with NFPF. The median follow-up period was 40.9 mo (range, 0.3-156.5 mo).

RESULTS: Twenty-four patients (10.8%) demonstrated NFPF, accompanied by lower albumin level, worse Child-Pugh scores, and model for end-stage liver disease scores. The portal hemodynamic features in the patients with NFPF were smaller diameter of the portal trunk; presence of short gastric vein, splenorenal shunt, or inferior mesenteric vein; and advanced collateral vessels (diameter > 8.7 mm, flow velocity > 10.2 cm/s, and flow volume > 310 mL/min). The cumulative incidence rates of NFPF were 6.5% at 1 year, 14.5% at 3 years, and 23.1% at 5 years. The collateral vessels characterized by flow velocity > 9.5 cm/s and those located at the splenic hilum were significant predictive factors for developing NFPF. The cumulative survival rate was significantly lower in the patients with NFPF (72.2% at 1 year, 38.5% at 3 years, 38.5% at 5 years) than in those with forward portal flow (84.0% at 1 year, 67.8% at 3 years, 54.3% at 5 years, P = 0.0123) using the Child-Pugh B and C classifications.

CONCLUSION: NFPF has a significant negative effect on the prognosis of patients with worse liver function reserve, suggesting the need for careful management.

Assessment of Spectral Doppler for an Array-Based Preclinical Ultrasound Scanner Using a Rotating Phantom

Velocity measurement errors were investigated for an array-based preclinical ultrasound scanner (Vevo 2100, FUJIFILM VisualSonics, Toronto, ON, Canada). Using a small-size rotating phantom made from a tissue-mimicking material, errors in pulse-wave Doppler maximum velocity measurements were observed. The extent of these errors was dependent on the Doppler angle, gate length, gate depth, gate horizontal placement and phantom velocity. Errors were observed to be up to 172% at high beam-target angles. It was found that small gate lengths resulted in larger velocity errors than large gate lengths, a phenomenon that has not previously been reported (e.g., for a beam-target angle of 0°, the error was 27.8% with a 0.2-mm gate length and 5.4% with a 0.98-mm gate length). The error in the velocity measurement with sample volume depth changed depending on the operating frequency of the probe. Some edge effects were observed in the horizontal placement of the sample volume, indicating a change in the array aperture size. The error in the velocity measurements increased with increased phantom velocity, from 22% at 2.4 cm/s to 30% at 26.6 cm/s. To minimise the impact of these errors, an angle-dependent correction factor was derived based on a simple ray model of geometric spectral broadening. Use of this angle-dependent correction factor reduces the maximum velocity measurement errors to <25% in all instances, significantly improving the current estimation of maximum velocity from pulse-wave Doppler ultrasound.

Initial kidney graft resistance index and the long-term cardiovascular mortality in transplanted patients: a paired grafts analysis

BACKGROUND

Cardiovascular complications remain the most frequent cause of death in kidney transplant recipients. We analysed the prognostic value of early measured resistance index (RI) in the aspect of long-term cardiovascular mortality. In order to eliminate potential donor-related confounders, we analysed the mortality of recipients, transplanted with organs procured from the same donor, in whom the initial RI values substantially differed.

METHODS

Doppler sonography was performed in 725 consecutive kidney graft recipients early after transplantation. We identified 133 pairs (266 patients) who received their kidney grafts from the same donor and their initial RI values differed by >0.1.

RESULTS

During 109 ± 37 months of follow-up after transplantation, 84 patients lost their graft and 29 died, 14 of them due to cardiovascular causes. Two groups of paired patients with higher RI and lower RI did not differ significantly with respect to their age, BMI, HLA mismatch and cold ischaemia time. There were more patients with diabetes in the higher RI group (14.3 versus 6.8%). Survival analysis revealed a higher mortality for cardiovascular (8.3 versus 2.3%, P = 0.02) and all causes (14.3 versus 7.5%, P = 0.06) among patients with higher initial RI values. In the Cox regression model, not including age, a higher RI value was a strong predictor of cardiovascular death (HR = 4.88), independent of previous cardiovascular episodes (HR = 6.78). Both these variables lost its significance as a predictors after inclusion of age in the regression model.

CONCLUSION

Increased intrarenal resistance index in the early posttransplant period may help to identify the recipients with increased cardiovascular risk.

Delayed Transcranial Echo-Contrast Bolus Arrival in Unilateral Internal Carotid Artery Stenosis and Occlusion

Some patients with internal carotid artery (ICA) occlusion or stenosis are at risk of developing a hemodynamic stroke. Transcranial ultrasonography using an echo-contrast bolus technique might be able to assess the extent of hemodynamic compromise. We describe a transcranial Doppler sonographic method that analyzes the differences in echo-contrast bolus arrival between both middle cerebral arteries after intravenous echo-contrast application. Ten patients with 50%-79% ICA stenosis, 10 patients with 80%-99% ICA stenosis and 22 patients with ICA occlusion were studied and compared with 15 age-matched controls. There were significant increases in delayed filling of the middle cerebral artery in both 80%-99% stenoses and occlusions compared with controls. The extent of the observed delays did not correlate with vasomotor reactivity. Echo-contrast bolus arrival time can be used to gain additional information on the intracranial hemodynamic effects of extracranial carotid artery disease that seems to be independent of the established ultrasound indices.

A comparison of Doppler waveform parameters versus flow-mediated vascular dilation of the brachial artery in pregnant women

OBJECTIVE

Flow mediated dilation of the brachial artery is impaired with endothelial dysfunction. We previously identified that brachial artery waveforms were changed in preeclamptic women. We therefore sought to compare Doppler waveform analysis with flow mediated vascular dilation (FMVD) measurements in pregnant women.

STUDY DESIGN

A cross sectional study of 71 pregnant women at >20weeks gestation comparing FMVD measurements with Doppler waveform parameters was performed. Research was conducted at three hospitals and two geographic settings; (1) Yale-New Haven Hospital in New Haven, CT, (2) Mount Hope Maternity and (3) Port of Spain General Hospital in Trinidad. Brachial artery Doppler waveform measurements were done at baseline and 90s post cuff-release. From the Doppler waveforms we assessed percent change in Peak Systolic Velocity (% ΔPSV), systolic acceleration, acceleration time and pulsatility index and compared them with the percent change in FMVD. Statistical analysis using Student's t tests and correlation coefficient was done as necessary.

RESULTS

Correlation analysis between the % change in the Doppler waveform parameters and the % change in mean FMVD identified only the waveform parameter of % ΔPSV as significantly correlated (p=0.040).

CONCLUSION

FMVD remains the gold standard for assessment of endothelial dysfunction. A correlation was observed between the Doppler measured % ΔPSV and FMVD, which may allow it to be used to assess endothelial dysfunction changes under different conditions was identified.

Real-time ultrasound: Key factor in identifying celiac artery compression syndrome

The median arcuate ligament syndrome (MALS) or celiac artery compression syndrome (CACS) is a rare entity, presenting clinically with postprandial abdominal pain and weight loss. The diagnosis is made on computed tomography (CT) angiography, which reveals extrinsic compression of the proximal part of the celiac artery by the median arcuate ligament, producing a characteristic hooked appearance. We report a case of the celiac artery compression syndrome, diagnosed by Doppler USG evaluation.

Hemodynamic effects of proximal supra-aortic artery stenosis on anterior cerebral artery

Alternating flow in the anterior cerebral artery is a rare finding, associated with innominate artery stenosis. We present a series of four patients with this finding on transcranial color coded sonography, under basal conditions. In all of these patients, vascular studies detected an ipsilateral proximal stenosis, three in the innominate artery and, for the first time, one at the left common carotid artery origin. Successful angioplasties with stenting were performed, resulting for the first time in the normalization of orthograde flow in all cases. We conclude that an early systolic hemodynamic compromise in the first segment of the anterior cerebral artery, in the form of alternating flow, is an indirect indicator of ipsilateral proximal stenosis in the supra-aortic arteries, either in the innominate artery or at the origin of the left common carotid artery.

Role of 3-D ultrasound in clinical obstetric practice: evolution over 20 years

The use of 3-D ultrasound in obstetrics has undergone dramatic development over the past 20 years. Since the first publications on this application in clinical practice, several 3-D ultrasound techniques and rendering modes have been proposed and applied to the study of fetal brain, face and cardiac anatomy. In addition, 3-D ultrasound has improved calculations of the volume of fetal organs and limbs and estimations of fetal birth weight. And furthermore, angiographic patterns of fetal organs and the placenta have been assessed using 3-D power Doppler ultrasound quantification. In this review, we aim to summarize current evidence on the clinical relevance of these methodologies and their application in obstetric practice.

Incidence of A-V Fistulas after Renal Biopsy of Native and Transplanted Kidney - Two Centers Experience

AIM:

The aim of the study is to make a retrospective analysis of the incidence of AV fistulas after renal biopsy (RB) of native and transplanted kidney.

MATERIALS AND METHODS:

Five hundred and sixteen (516) RB were analyzed. One hundred twenty nine (129) were native kidneys RB performed in Clinic of Nephrology (CN), 190 were performed in Clinic of Nephrology and transplantation (CNT) and 197 were transplanted kidney biopsies from the same clinic. Biopsy technique type Gun with needle 14G, 16 and 18 G was used in CN, CNT used the same technique with needles 16G. Doppler ultrasound was made for A-V fistulas diagnosis.

RESULTS:

The A-V fistulas incidence was 0.8%. The frequency of A-V fistulas registered in CN was significantly higher than that registered in CNT (2.3% vs. 0.5%, p < 0.01). Biopsies performed by 14 G needles provide a higher percentage of A-V fistulas compared to those done by 16 G. (3.3% vs. 2.4%, p < 0.5). The frequency of the A-V fistulas in native and transplanted kidneys in CNT was similar (0.5% vs. 0.5%, p > 0.05).

CONCLUSION:

The A-V fistulas incidence is very low. The needle thickness is an important factor relevant to the risk of occurrence of A-V fistulas.

Comparison of muscle BOLD responses to arterial occlusion at 3 and 7 Tesla

PURPOSE

The purpose of this study was to determine the feasibility of muscle BOLD (mBOLD) imaging at 7 Tesla (T) by comparing the changes in R2* of muscle at 3 and 7T in response to a brief period of tourniquet-induced ischemia.

METHODS

Eight subjects (three male), aged 29.5 ± 6.1 years (mean ± standard deviation, SD), 167.0 ± 10.6 cm tall with a body mass of 62.0 ± 18.0 kg, participated in the study. Subjects reported to the lab on four separate occasions including a habituation session, two MRI scans, and in a subset of subjects, a session during which changes in blood flow and blood oxygenation were quantified using Doppler ultrasound (U/S) and near-infrared spectroscopy (NIRS) respectively. For statistical comparisons between 3 and 7T, R2* rate constants were calculated as R2* = 1/T2*.

RESULTS

The mean preocclusion R2* value was greater at 7T than at 3T (60.16 ± 2.95 vs. 35.17 ± 0.35 s(-1), respectively, P < 0.001). Also, the mean ΔR2 *END and ΔR2*POST values were greater for 7T than for 3T (-2.36 ± 0.25 vs. -1.24 ± 0.39 s(-1), respectively, Table 1).

CONCLUSION

Muscle BOLD contrast at 7T is as much as six-fold greater than at 3T. In addition to providing greater SNR and CNR, 7T mBOLD studies may offer further advantages in the form of greater sensitivity to pathological changes in the muscle microcirculation.

Recent developments in vascular ultrasound technology

This article describes four technologies relevant to vascular ultrasound which are available commercially in 2015, and traces their origin back through the research literature. The technologies are 3D ultrasound and its use in plaque volume estimation (first described in 1994), colour vector Doppler for flow visualisation (1994), wall motion for estimation of arterial stiffness (1968), and shear wave elastography imaging of the arterial wall (2010). Overall these technologies have contributed to the understanding of vascular disease but have had little impact on clinical practice. The basic toolkit for vascular ultrasound has for the last 25 years been real-time B-mode, colour flow and spectral Doppler. What has changed over this time is improvement in image quality. Looking ahead it is noted that 2D array transducers and high frame rate imaging continue to spread through the commercial vascular ultrasound sector and both have the potential to impact on clinical practice.

Doppler ultrasound for diagnosis of soft tissue sarcoma: efficacy of ultrasound-based screening score

BACKGROUND

The utility of ultrasound imaging in the screening of soft-part tumours (SPTs) has been reported. We classified SPTs according to their blood flow pattern on Doppler ultrasound and re-evaluated the efficacy of this imaging modality as a screening method. Additionally, we combined Doppler ultrasound with several values to improve the diagnostic efficacy and to establish a new diagnostic tool.

PATIENTS AND METHODS

This study included 189 cases of pathologically confirmed SPTs (122 cases of benign disease including SPTs and tumour-like lesions and 67 cases of malignant SPTs). Ultrasound imaging included evaluation of vascularity by colour Doppler. We established a scoring system to more effectively differentiate malignant from benign SPTs (ultrasound-based sarcoma screening [USS] score).

RESULTS

The mean scores in the benign and malignant groups were 1.47 ± 0.93 and 3.42 ± 1.30, respectively. Patients with malignant masses showed significantly higher USS scores than did those with benign masses (p < 1 × 10(-10)). The area under the curve was 0.88 by receiver operating characteristic (ROC) analysis. Based on the cut-off value (3 points) calculated by ROC curve analysis, the sensitivity and specificity for a diagnosis of malignant SPT was 85.1% and 86.9%, respectively.

CONCLUSIONS

Assessment of vascularity by Doppler ultrasound alone is insufficient for differentiation between benign and malignant SPTs. Preoperative diagnosis of most SPTs is possible by combining our USS score with characteristic clinical and magnetic resonance imaging findings.

Vascular Doppler ultrasonographic indices in cirrhosis: a case-control study with emphasis on the common carotid arteries

PURPOSE

To compare vascular Doppler waveform indices, particularly in the common carotid arteries, between cirrhotic and healthy subjects.

MATERIALS AND METHODS

A total of 60 patients with Class-B cirrhosis and 60 healthy matched counterparts were enrolled in this prospective study. Vascular Doppler waveform parameters including resistance and/or pulsatility indices (RI and PI, respectively) were obtained from the common carotid, renal, celiac, superior mesenteric, femoral and brachial arteries.

RESULTS

Compared to patients, healthy subjects had significantly higher mean PI and RI obtained from the common carotid (1.53 ± 0.20 vs. 1.43 ± 0.14, p = 0.03; 0.75 ± 0.02 vs. 0.72 ± 0.02, p < 0.001, respectively) and celiac arteries (2.00 ± 0.36 vs. 1.81 ± 0.34, p = 0.03; 0.80 ± 0.03 vs. 0.78 ± 0.02, p < 0.001, respectively). Both the mean PI and RI derived from the renal arteries, in contrast, were significantly higher in patients compared to that in controls (1.05 ± 0.13 vs. 1.11 ± 0.07, p = 0.03; 0.59 ± 0.03 vs. 0.63 ± 0.03, p < 0.001, respectively). The mean vascular impedance values obtained from the remaining arteries were comparable between the two groups.

CONCLUSIONS

Blood flow increases in the common carotid and celiac arteries of Class-B cirrhotic patients with elevated renovascular impedance.

Loss of echogenicity and onset of cavitation from echogenic liposomes: pulse repetition frequency independence

Echogenic liposomes (ELIP) are being developed for the early detection and treatment of atherosclerotic lesions. An 80% loss of echogenicity of ELIP has been found to be concomitant with the onset of stable and inertial cavitation. The ultrasound pressure amplitude at which this occurs is weakly dependent on pulse duration. It has been reported that the rapid fragmentation threshold of ELIP (based on changes in echogenicity) is dependent on the insonation pulse repetition frequency (PRF). The study described here evaluates the relationship between loss of echogenicity and cavitation emissions from ELIP insonified by duplex Doppler pulses at four PRFs (1.25, 2.5, 5 and 8.33 kHz). Loss of echogenicity was evaluated on B-mode images of ELIP. Cavitation emissions from ELIP were recorded passively on a focused single-element transducer and a linear array. Emissions recorded by the linear array were beamformed, and the spatial widths of stable and inertial cavitation emissions were compared with the calibrated azimuthal beamwidth of the Doppler pulse exceeding the stable and inertial cavitation thresholds. The inertial cavitation thresholds had a very weak dependence on PRF, and stable cavitation thresholds were independent of PRF. The spatial widths of the cavitation emissions recorded by the passive cavitation imaging system agreed with the calibrated Doppler beamwidths. The results also indicate that 64%-79% loss of echogenicity can be used to classify the presence or absence of cavitation emissions with greater than 80% accuracy.

Diabetic symmetric polyneuropathy is associated with increased aortal stiffening but not cerebral angiopathy in type 1 diabetes

INTRODUCTION

Diabetic symmetric polyneuropathy (DSP) and cerebral microangiopathy are common complications of type 1 diabetes (T1DM). However, little is known about associations between DSP, cerebral microcirculation and macrovascular injury in T1DM. We aimed to assess relationships between those complications.

MATERIAL AND METHODS

We examined 42 patients (25 females; mean age 37.1±5.6years) with T1DM (mean disease duration 20.6±6.1years). DSP was diagnosed with the use of quantitative vibration sensory testing (QVST) and Michigan Neuropathy Screening Instrument (MNSI). Cerebral microvasculature was evaluated with measurements of vasomotor reactivity reserve (VMR) and pulsatility index (PI) of middle cerebral artery, macroangiopathic injury by measuring intima-media complex thickness (IMT) in the common carotid artery and carotid-femoral pulse-wave velocity (PWV).

RESULTS

Patients with DSP (33.3%) showed higher PWV than those without DPS (10.5 vs 9.1m/s; P=0.03); no differences concerning VMR, PI or IMT existed. There were correlations between PWV and vibration perception thresholds (VPT) (r=0.44; P=0.004) and MNSI score (r=0.43; P=0.003); VPT showed impact on PWV (beta 0.34; P<0.03).

CONCLUSIONS

DSP is associated with systemic macroangiopathy, reflected by increased carotid-femoral PWV, but not with the cerebral macro- and microangiopathy.

Changes in vitelline and utero-placental hemodynamics: implications for cardiovascular development

Analyses of cardiovascular development have shown an important interplay between heart function, blood flow, and morphogenesis of heart structure during the formation of a four-chambered heart. It is known that changes in vitelline and placental blood flow seemingly contribute substantially to early cardiac hemodynamics. This suggests that in order to understand mammalian cardiac structure-hemodynamic functional relationships, blood flow from the extra-embryonic circulation needs to be taken into account and its possible impact on cardiogenesis defined. Previously published Doppler ultrasound analyses and data of utero-placental blood flow from human studies and those using the mouse model are compared to changes observed with environmental exposures that lead to cardiovascular anomalies. Use of current concepts and models related to mechanotransduction of blood flow and fluid forces may help in the future to better define the characteristics of normal and abnormal utero-placental blood flow and the changes in the biophysical parameters that may contribute to congenital heart defects. Evidence from multiple studies is discussed to provide a framework for future modeling of the impact of experimental changes in blood flow on the mouse heart during normal and abnormal cardiogenesis.

Renal artery stenosis on duplex ultrasound due to inferior vena cava filter leg impingement

We present a case study of renal artery duplex findings for new onset of hypertension in a young woman with a history of inferior vena cava filter placed a year prior and failed percutaneous retrieval. Duplex ultrasound showed significantly elevated velocities in the mid-right renal artery, consistent with renal artery stenosis. Computed tomography angiography images suggested that a leg from the inferior vena cava filter was impinging on her right renal artery, with perforation through the vena cava possibly into the wall of her duodenum. Open surgical intervention was required to disentangle the filter legs from the wall of the duodenum and relieve impingement on the right renal artery with thrombolysis of clot found within the right renal artery.

Are there any relationships between umbilical artery Pulsatility Index and macrosomia in fetuses of type I diabetic mothers?

OBJECTIVE

To establish whether there are relationships between umbilical artery Pulsatility Index (PI) and fetal macrosomia in pregnancies complicated by type I diabetes.

METHODS

In a retrospective observational study, 102 singleton pregnant women with type I diabetes were considered. Umbilical artery PI was measured by Doppler ultrasonography within one week from delivery and related to neonatal weight. Pregnancies were grouped according to birtweight in macrosomic group (≥4000 g) and normal growth group (<4000 g). Relationships between umbilical artery PI and birth weight and birth weight centile were tested by Pearson's correlation analysis. Further umbilical artery PI values were compared between macrosomic and normally grown fetuses.

RESULTS

Birth weight was ≥4000 g in 24 pregnancies (23.5%). A significant relationship was found between umbilical artery PI and neonatal weight (r = 0.512; p < 0.01) and neonatal weight centile (r = 0.400; p < 0.01). Umbilical artery PI were significantly lower (t = -6.013; p < 0.001) in the macrosomic group (0.78; 95% confidence interval (CI) 0.73-0.84) than in the normal growth group (1.00; 95% CI 0.97-1.04).

CONCLUSIONS

In pregnancies complicated by type I diabetes there is a significant relationship between umbilical artery PI value before delivery and absolute birth weight and birth weight centile. Macrosomic fetuses show a significant reduction in umbilical artery PI when compared with diabetic pregnancies without fetal overgrowth.

Packed red blood cell transfusion (PRBC) attenuates intestinal blood flow responses to feedings in pre-term neonates with normalization at 24 hours

OBJECTIVE

To determine whether packed red blood cell (PRBC) transfusion affects post-prandial superior mesenteric artery blood flow velocities (SMA BFVs) in very-low birth weight (VLBW) neonates and if so, at what time point after transfusion restoration of previous SMA BFV patterns occurs.

DESIGN/METHODS

VLBW pre-term neonates, older than 14 days and tolerating bolus enteral feedings administered every 3 h were enrolled in this prospective observational study. Pulsed Doppler ultrasound was used to measure pre- and post-prandial (at 45 min) time-averaged mean, peak and end diastolic velocities (TAMV, PSV, EDV) immediately before and after 15 ml/kg of PRBC transfusion was given over 3 h; patent ductus arteriosus (PDA) status was also evaluated. Subsequent pre- and post-prandial SMA BFVs were recorded 24 and 48 h after the transfusion.

RESULTS

Pre- and post-prandial measurements were obtained for 21 out of 25 enrolled infants. Post-prandial SMA BFVs were attenuated during the feedings immediately after transfusion; at 24 and 48 h after transfusion, changes in post-prandial SMA BFVs were similar to those measured prior to transfusion; the presence of the PDA did not affect results.

CONCLUSIONS

PRBC transfusion blunted SMA BFV responses to feedings immediately after the transfusion with normalization observed 24 h post-transfusion.

Application of high frequency color Doppler ultrasound in the monitoring of rheumatoid arthritis treatment

The aim of the present study was to explore the use of high frequency color Doppler ultrasound to measure synovial thickness and blood flow to assess the therapeutic value of the recombinant human tumor necrosis factor (TNF) II receptor antibody fusion protein in rheumatoid arthritis (RA) treatment. A total of 36 clinically-diagnosed patients with RA were treated with methotrexate tablets or the recombinant TNF-receptor antibody fusion protein for 24 weeks. Joint synovial thickness and synovial blood flow integrity were monitored by high frequency color Doppler in the second metacarpophalangeal joint in one hand. The correlation of the erythrocyte sedimentation rate, C-reactive protein (CRP) and 28-joint disease activity score (DAS28) with the ultrasound parameters were analyzed. Metacarpophalangeal second joint 2 (MCP2) synovial thickness, wrist joint synovial thickness and MCP2 synovial blood flow, prior and subsequent to the treatment, have a high correlation with DAS28 (P<0.05), and the MCP2 synovial blood flow integral has a strong correlation with CRP. Evaluating the wrist joint synovial thickness and synovial integrity of the second metacarpophalangeal joint using high frequency ultrasound detection can effectively evaluate the disease status in patients with RA. This procedure is potentially valuable as a means of evaluating the curative effects of RA treatments.

Potential use of Doppler perfusion index in detection of occult liver metastases from colorectal cancer

Many clinical and preclinical studies demonstrated that measurements of liver hemodynamic [Doppler perfusion index (DPI)] may be used to accurately diagnose and predict liver metastases from primary colorectal cancer in a research setting. However, Doppler measurements have some serious limitations when applied to general population. Ultrasound is very operator-dependent, and requires skilled examiners. Also, many conditions may limit the use of Doppler ultrasound and ultrasound in general, such as the presence of air in digestive tract, cardiac arrhythmias, vascular anomalies, obesity and other conditions. Therefore, in spite of the results from clinical studies, its value may be limited in everyday practice. On the contrary, scientific research of the DPI in detection of liver metastases is of great importance, since current research speaks strongly for the presence of systemic vasoactive substance responsible for observed hemodynamic changes. Identification of such a systemic vasoactive substance may lead to the development of a simple and reproducible laboratory test that may reliably identify the presence of occult liver metastases and therefore increase the success of adjuvant chemotherapy through better selection of patients. Further research in this subject is therefore of great importance.

Umbilical and fetal middle cerebral artery Doppler reference ranges in a twin population followed longitudinally from 24 to 38 weeks' gestation

OBJECTIVE

To construct monochorionic diamniotic (MCDA) and dichorionic diamniotic (DCDA) twin reference ranges for umbilical artery (UA) pulsatility index (PI), UA resistance index (RI), fetal middle cerebral artery (MCA) PI and peak systolic velocity (PSV) and cerebroplacental ratio (CPR) from 24 weeks' to 38 weeks' gestation and compare these with published normal values for singleton pregnancies.

METHODS

This prospective multicenter cohort study included 1028 unselected twin pairs recruited over a 2-year period. Participants with dichorionic twins underwent fortnightly ultrasound surveillance from 24 weeks' gestation, with monochorionic twins being followed every 2 weeks from 16 weeks until delivery. A total of 7536 fetal Doppler examinations in 618 twin pregnancies were included in the analysis, with reference ranges for MCDA and DCDA pregnancies constructed for each of the Doppler indices using multilevel modeling.

RESULTS

UA-PI and UA-RI appear to be higher in twins than in singletons, and MCA-PI and MCA-PSV appear to be lower. The CPR also appears to be lower in twins than in singletons. Similar MCA indices were observed in MCDA and DCDA twins.

CONCLUSION

We have established longitudinal reference ranges for UA-PI and UA-RI, MCA-PI and MCA-PSV and CPR in twin pregnancies, which appear to differ from those in singleton pregnancies. The derived twin-specific reference ranges may be more appropriate in the surveillance of these high-risk pregnancies. Applying the singleton CPR cut-off of ≤ 1.0 may lead to a large number of false-positive diagnoses of cerebral redistribution in twin fetuses.

Prevalence of Achilles and patellar tendinopathy and their association to intratendinous changes in adolescent athletes

Achilles (AT) and patellar tendons (PT) are commonly affected by tendinopathy in adult athletes but prevalence of symptoms and morphological changes in adolescents is unclear. The study aimed to determine prevalence of tendinopathy and intratendinous changes in ATs and PTs of adolescent athletes. A total of 760 adolescent athletes (13.0 ± 1.9 years; 160 ± 13 cm; 50 ± 14 kg) were examined. History, local clinical examination, and longitudinal Doppler ultrasound analysis for both ATs and PTs were performed including identification of intratendinous echoic changes and vascularization. Diagnosis of tendinopathy was complied clinically in case of positive history of tendon pain and tendon pain on palpation. Achilles tendinopathy was diagnosed in 1.8% and patellar tendinopathy in 5.8%. Vascularizations were visible in 3.0% of ATs and 11.4% of PTs, hypoechogenicities in 0.7% and 3.2% as well as hyperechogenicities in 0% and 0.3%, respectively. Vascularizations and hypoechogenicities were statistically significantly more often in males than in females (P ≤ 0.02). Subjects with patellar tendinopathy had higher prevalence of structural intratendinous changes than those without PT symptoms (P ≤ 0.001). In adolescent athletes, patellar tendinopathy is three times more frequent compared with Achilles tendinopathy. Longitudinal studies are necessary to investigate physiological or pathological origin of vascularizations and its predictive value in development of tendinopathy.

Roles of ultrasound and power Doppler ultrasound for diagnosis of Hashimoto thyroiditis in anti-thyroid marker-positive euthyroid subjects

PURPOSE

The present study was performed to investigate the contribution of ultrasonographic (US) findings to diagnosis in anti-thyroid marker-positive patients with normal hormone levels among euthyroid subjects with Hashimoto's thyroiditis (HT).

METHODS

Forty premenopausal euthyroid patients with a median age of 32 years (range, 20-44 years) with normal levels of free triiodothyronine (FT3) and free thyroxine (FT4), and elevated anti-thyroid peroxidase (TPO) antibodies were enrolled in this study. A control group of 46 healthy individuals with a median age of 29 years (range, 18-43 years) was composed of randomly selected volunteers. The examinations included basic morphometric (measurement of thyroid gland dimensions in three axes, the volume of each thyroid lobe, and the total thyroid volume), morphological grayscale imaging (echogenicity, nodularity, septations, undulation of the margins, and reactive lymph nodes), and thyroid gland vascularity.

RESULTS

There were no statistically significant differences in morphometric parameters of the thyroid gland between the study and control groups. There were significant differences in the presence of nodularity, undulation of the gland margins, septations inside the glands, infrathyroidal and/or pretracheal reactive lymph nodes, and increased vascularity on power Doppler imaging between the groups. The use of all parameters together yielded a sensitivity of 90%, specificity of 84.8%, positive predictive value (PPV) of 83.7%, negative predictive value (NPV) of 90.7%, and accuracy of 87.2% for diagnosis of HT.

CONCLUSIONS

US and power Doppler US are helpful for the diagnosis of HT in anti-thyroid marker-positive patients with normal thyroid hormone levels.

Esophageal varix predictive performance of lower esophageal Doppler signals during the swallowing process

The objective of this study was to assess whether the swallowing action can improve the display of lower esophageal Doppler signals (LEDS) during transabdominal ultrasound (TUS). Eighty-four patients with cirrhosis underwent both TUS and endoscopic examination for esophageal varices (EVs). LEDS were assessed under the esophageal resting state and during the swallowing process. Univariate analysis indicated that spleen diameter, spleen vein diameter, portal vein diameter, LEDS and left gastric vein hepatofugal flow were significantly associated with the presence of EVs. No LEDS were detected in patients without EVs at rest or during swallowing. Of the 69 patients with EVs, LEDS could be detected in 21 cases (30.4%) in the esophageal resting state and in 58 cases (84.1%) during the swallowing process. Compared with the esophageal resting state, the swallowing action can significantly improve display of LEDS during TUS (p = 0.000), which may be beneficial for TUS detection of EVs.

Audio spectrum analysis of umbilical artery Doppler ultrasound signals applied to a clinical material

Analysis of umbilical artery flow velocity waveforms characterized by pulsatility index (PI) is used to evaluate fetoplacental circulation in high-risk pregnancies. However, an experienced sonographer may be able to further differentiate between various timbres of Doppler audio signals. Recently, we have developed a method for objective audio signal characterization; the method has been tested in an animal model. In the present pilot study, the method was for the first time applied to human pregnancies. Doppler umbilical artery velocimetry was performed in 13 preterm fetuses before and after two doses of 12 mg betamethasone. The auditory measure defined by the frequency band where the spectral energy had dropped 15 dB from its maximum level (MAXpeak-15 dB ), increased two days after betamethasone administration (p = 0.001) parallel with a less pronounced decrease in PI (p = 0.04). The new auditory parameter MAXpeak-15 dB reflected the changes more sensitively than the PI did.

The S curve: a novel morphological finding in the internal carotid artery in patients with fibromuscular dysplasia

Fibromuscular dysplasia (FMD) is a non-atherosclerotic vascular disease commonly affecting the renal and internal carotid arteries (ICAs). A previously unrecognized finding is a redundancy of the mid-distal ICA in FMD patients causing an 'S'-shaped curve. Carotid artery duplex ultrasounds were reviewed in 116 FMD patients to determine S-curve prevalence. FMD patients with an S curve were matched to four control patients divided equally into two groups: (1) age and sex-matched and (2) age ≥70 and sex-matched. S curves were present in 37 (32%) FMD patients. Of these, nine (24%) had angiographic evidence of FMD in their ICA only, 13 (35%) had renal artery FMD only, and 15 (41%) had both ICA and renal FMD. Two patients in the age and sex-matched group had S curves (odds ratio 16.86, 95% CI 3.92-72.48; p<0.0001) while 12 (16.2%) patients in the age ≥70 and sex-matched group had S curves (odds ratio 2.42, 95% CI 1.16-5.03; p=0.016). In conclusion, the S curve is a novel morphological pattern of the mid-distal ICA. While the S curve may not be specific, its presence in individuals <70 years old should alert the clinician to the possibility that FMD is present.

Assessment of flow distribution in the mouse fetal circulation at late gestation by high-frequency Doppler ultrasound

This study used high-frequency ultrasound to evaluate the flow distribution in the mouse fetal circulation at late gestation. We studied 12 fetuses (embryonic day 17.5) from 12 pregnant CD1 mice with 40 MHz ultrasound to assess the flow in 11 vessels based on Doppler measurements of blood velocity and M-mode measurements of diameter. Specifically, the intrahepatic umbilical vein (UVIH), ductus venosus (DV), foramen ovale (FO), ascending aorta (AA), main pulmonary artery (MPA), ductus arteriosus (DA), descending thoracic aorta (DTA), common carotid artery (CCA), inferior vena cava (IVC), and right and left superior vena cavae (RSVC, LSVC) were examined, and anatomically confirmed by micro-CT. The mouse fetal circulatory system was found to be similar to that of the humans in terms of the major circuit and three shunts, but characterized by bilateral superior vena cavae and a single umbilical artery. The combined cardiac output (CCO) was 1.22 ± 0.05 ml/min, with the left ventricle (flow in AA) contributing 47.8 ± 2.3% and the right ventricle (flow in MPA) 52.2 ± 2.3%. Relative to the CCO, the flow percentages were 13.6 ± 1.0% for the UVIH, 10.4 ± 1.1% for the DV, 35.6 ± 2.4% for the DA, 41.9 ± 2.6% for the DTA, 3.8 ± 0.3% for the CCA, 29.5 ± 2.2% for the IVC, 12.7 ± 1.0% for the RSVC, and 9.9 ± 0.9% for the LSVC. The calculated flow percentage was 16.6 ± 3.4% for the pulmonary circulation and 31.2 ± 5.3% for the FO. In conclusion, the flow in mouse fetal circulation can be comprehensively evaluated with ultrasound. The baseline data of the flow distribution in normal mouse fetus serve as the reference range for future studies.

Renal transplantation parenchymal complications: what Doppler ultrasound can and cannot do

Kidney transplantation is the treatment of choice in end-stage renal disease, given the better quality of life of transplanted patients when compared with patients on maintenance dialysis. In spite of surgical improvements and new immunosuppressive regimens, parts of transplanted grafts still develop chronic dysfunction. Ultrasonography, both in B-mode and with Doppler ultrasound, is an important diagnostic tool in case of clinical conditions which might impair kidney function. Even though ultrasonography is considered fundamental in the diagnosis of vascular and surgical complications of the transplanted kidney, its role is not fully understood in case of parenchymal complications of the graft. The specificity of Doppler is low both in case of acute complications, such as acute tubular necrosis, drugs toxicity and acute rejection, and in case of chronic conditions, such as chronic allograft nephropathy. Single determinations of resistance indices present low diagnostic accuracy, which is higher in case of successive measurements performed during the follow-up of the graft. Modern techniques such as tissue pulsatility index, maximal fractional area and contrast-enhanced ultrasound increase ultrasonography diagnostic power in case of parenchymal complications of the transplanted kidney.

Chronic assessment of cerebral hemodynamics during rat forepaw electrical stimulation using functional ultrasound imaging

Functional ultrasound imaging is a method recently developed to assess brain activity via hemodynamics in rodents. Doppler ultrasound signals allow the measurement of cerebral blood volume (CBV) and red blood cells' (RBCs') velocity in small vessels. However, this technique originally requires performing a large craniotomy that limits its use to acute experiments only. Moreover, a detailed description of the hemodynamic changes that underlie functional ultrasound imaging has not been described but is essential for a better interpretation of neuroimaging data. To overcome the limitation of the craniotomy, we developed a dedicated thinned skull surgery for chronic imaging. This procedure did not induce brain inflammation nor neuronal death as confirmed by immunostaining. We successfully acquired both high-resolution images of the microvasculature and functional movies of the brain hemodynamics on the same animal at 0, 2, and 7 days without loss of quality. Then, we investigated the spatiotemporal evolution of the CBV hemodynamic response function (HRF) in response to sensory-evoked electrical stimulus (1 mA) ranging from 1 (200 μs) to 25 pulses (5s). Our results indicate that CBV HRF parameters such as the peak amplitude, the time to peak, the full width at half-maximum and the spatial extent of the activated area increase with stimulus duration. Functional ultrasound imaging was sensitive enough to detect hemodynamic responses evoked by only a single pulse stimulus. We also observed that the RBC velocity during activation could be separated in two distinct speed ranges with the fastest velocities located in the upper part of the cortex and slower velocities in deeper layers. For the first time, functional ultrasound imaging demonstrates its potential to image brain activity chronically in small animals and offers new insights into the spatiotemporal evolution of cerebral hemodynamics.

The relationship between blood pressure and sciatic nerve blood flow velocity in rats with insulin-treated experimental diabetes

Peripheral nerve blood flow (NBF) does not autoregulate but, instead, responds passively to changes in mean arterial pressure (MAP). How this relationship is impacted by insulin-treated experimental diabetes (ITED) is unknown. We tested the hypothesis that ITED will reduce NBF across a range of MAP in Sprague Dawley rats. Following 10 weeks of control or ITED conditions, conscious MAP (tail-cuff) was measured, and under anaesthesia, the MAP (carotid artery catheter, pressure transducer) and NBF (Doppler ultrasound, 40 MHz) responses to sodium nitroprusside (60 µg/kg) and phenylephrine (12 µg/kg) infusion were recorded (regression equations for MAP vs NBF were created for each rodent). Thereafter, motor nerve conduction velocity (MNCV) and nerve vascularization (haematoxylin and eosin stain) were determined. Conscious MAP was higher and MNCV was lower in the ITED group (p < 0.01). In response to drug infusions, the ΔMAP and ΔNBF were similar between groups (p ≥ 0.18). Estimated conscious NBF (based on substituting conscious MAP values into each individual regression equation) was greater in the ITED group (p < 0.01). Sciatic nerve vascularization was similar between groups (p ≥ 0.50). In contrast to the hypothesis, NBF was not reduced across a range of MAP. In spite of increased estimated conscious NBF values, MNCV was reduced in rats with ITED.

Acute transplant renal artery thrombosis due to distal renal artery stenosis: A case report and review of the literature

BACKGROUND

Acute renal artery thrombosis is a devastating complication of renal transplantation that can result in graft loss if not detected early. Surgical and technical errors are the major cause of renal artery thrombosis. In this article, for the first time, we are reporting a case of acute renal artery thrombosis that developed early post-transplantation due to distal renal artery stenosis.

CASE PRESENTATION

A 71-year-old woman presented with nausea, vomiting and decreased urine output 7 days after a deceased donor kidney transplant. Doppler ultrasound showed absent renal and venous flow in the transplanted kidney. Transplant renal artery angiogram showed renal artery thrombosis. Catheterization and thrombectomy were done in the occluded renal artery. After thrombectomy, renal angiogram showed distal renal artery stenosis which was dilated by stenting. Post-stenting angiogram showed good blood flow in the entire renal arterial system. However, the patient(,)s kidney function did not improve within next 24 hours and the patient eventually lost the kidney. Kidney biopsy showed widespread kidney infarction with no evidence of rejection.

CONCLUSIONS

Our case shows that renal artery thrombosis can develop due to distal renal artery stenosis and if not detected early could result in graft loss.

The deformation and longitudinal excursion of median nerve during digits movement and wrist extension

The use of electronic devices, such as mobile phones and computers, has increased drastically among the young generation, but the potential health effects of carpal tunnel syndrome (CTS) on university students has not been comprehensively examined. Thirty-one university students aged 18 to 25 y with no symptoms of CTS were successfully recruited in this study. By using noninvasive ultrasonography, the morphological characteristics of the median nerve of each volunteer, and the extent of its longitudinal excursion movement under experimental conditions, in which a real operating environment of electronic devices was simulated, were quantified. The results demonstrated that the median nerve at the carpal tunnel inlet was flattened during wrist extension: the flattening ratio increased from 3.40 ± 0.91 at the neutral position to 4.10 ± 1.11 at the angle of 30° and 4.09 ± 1.11 at the angle of 45°. In addition, the median nerve became swollen after the students performed rapid mobile-phone keying for 5 min, indicated by a significant increase in the cross-sectional area from 6.05 ± 0.97 mm(2) to 7.56 ± 1.39 mm(2). Passive longitudinal excursion was observed at the median nerve when the students performed mouse-clicking (2.4 ± 1.0 mm) and mobile-phone keying tasks (1.7 ± 0.6 mm), with the mouse-clicking task generating a greater extent of longitudinal excursion than the mobile-phone keying task did. In conclusion, the findings of the present study verify the potential harm caused by using electronic devices while maintaining an inappropriate wrist posture for a substantial period.

Assessment of flow distribution in the mouse fetal circulation at late gestation by high-frequency Doppler ultrasound

This study used high-frequency ultrasound to evaluate the flow distribution in the mouse fetal circulation at late gestation. We studied 12 fetuses (embryonic day 17.5) from 12 pregnant CD1 mice with 40 MHz ultrasound to assess the flow in 11 vessels based on Doppler measurements of blood velocity and M-mode measurements of diameter. Specifically, the intrahepatic umbilical vein (UVIH), ductus venosus (DV), foramen ovale (FO), ascending aorta (AA), main pulmonary artery (MPA), ductus arteriosus (DA), descending thoracic aorta (DTA), common carotid artery (CCA), inferior vena cava (IVC), and right and left superior vena cavae (RSVC, LSVC) were examined, and anatomically confirmed by micro-CT. The mouse fetal circulatory system was found to be similar to that of the humans in terms of the major circuit and three shunts, but characterized by bilateral superior vena cavae and a single umbilical artery. The combined cardiac output (CCO) was 1.22 ± 0.05 ml/min, with the left ventricle (flow in AA) contributing 47.8 ± 2.3% and the right ventricle (flow in MPA) 52.2 ± 2.3%. Relative to the CCO, the flow percentages were 13.6 ± 1.0% for the UVIH, 10.4 ± 1.1% for the DV, 35.6 ± 2.4% for the DA, 41.9 ± 2.6% for the DTA, 3.8 ± 0.3% for the CCA, 29.5 ± 2.2% for the IVC, 12.7 ± 1.0% for the RSVC, and 9.9 ± 0.9% for the LSVC. The calculated flow percentage was 16.6 ± 3.4% for the pulmonary circulation and 31.2 ± 5.3% for the FO. In conclusion, the flow in mouse fetal circulation can be comprehensively evaluated with ultrasound. The baseline data of the flow distribution in normal mouse fetus serve as the reference range for future studies.