Doppler US of the liver made simple

Aerobic Training and Ointment Effect on range of motion, von Willebrand factor, vascular endothelial factor and Femoral Artery Hemodynamics in Joint Contracture: A Rat Model

OBJECTIVE

Using a rat model, we investigated the effect of multidisciplinary rehabilitation, including aerobic training and ointment, on the ROM, vWF, VEGF content, and femoral artery hemodynamics in rats with joint contracture.

METHODS

A total of 44 Wistar rats were divided into the normal control group (NC, eight rats) and the experimental group (EG). A joint contracture model was established for the rats in the EG group by an external fixator. After fixator removal, 32 rats are further divided into the MC, SC, RE, and SR groups (n = 8). Before and after the 42 day intervention, the ROM, vWF, VEGF, PS, ED, and RI were measured using X-ray imaging, ELISA, and color Doppler ultrasound, respectively.

RESULTS

After fixator removal, ROM for EG group was lower than that of the NC group (p < .01). After the intervention, ROM for the SR, RE, and SC groups was improved. The ROM for the SR group reached a similar value for NC group. vWF and VEGF levels in SR group were lower than in the MC, SC, and RE groups (p < .05), and had a similar value to the NC groups. PS value for SR and RE groups was higher than the MC and SC groups. The RI value for SR group was higher than that of NC and MC groups.

CONCLUSION

Multidisciplinary rehabilitation used in this study can treat joint contracture synergistically. It improves the ROM of the joint, reduces the content of vWF and VEGF, and improves the femoral artery hemodynamics.

The resistive and pulsatility indices of the dorsal metatarsal artery for the screening of peripheral lower artery disease in patients with and without diabetes

BACKGROUND

In lower extremity peripheral artery disease (PAD), the ankle-brachial index (ABI) is an easily reproducible diagnostic tool for PAD, but it loses reliability when > 1.4 due to calcification of the vessel wall. Patients with diabetes are at higher risk for wall calcification. In order to overcome the limitation and reliability of ABI, particularly in patients with diabetes, we decided to assess resistive (RI) and pulsatility index (PI) by ultrasound doppler of the dorsal metatarsal artery (DMA).

RESULTS

We therefore analyzed 51 legs (32 patients), evaluating the correlation between PI, RI, and ABI. Patients with diabetes were 21 (65.6 %), accounting for 33 legs (64.7 %). Out of 51 legs assessed, 37 (72.5 %) cases had compressible arteries, whereas in 14 legs (27.5 %) ABI was not calculable due to wall calcification. PAD was significantly associated with lower both RI and PI of the DMA (both p < 0.000). RI, but not PI, showed a significant correlation (r = 0.535) with ABI, when ABI was less than 1.4, but not when ABI > 1.4. When analyzed separately, patients with diabetes showed a similar figure in comparison with those without diabetes (r = 0.600), RI, but not PI, showed a significant correlation with ABI.

CONCLUSION

Dorsal metatarsal artery resistive index (MARI) showed a significant inverse correlation with PAD, similarly to ABI, irrespective of the presence of diabetes. MARI seems to be an effective screening tool for PAD even in patients with wall calcification. Further studies are needed for confirming the results of the present pilot study.

Portal vein pulsatility: An important sonographic tool assessment of systemic congestion for critical ill patients

In this editorial we comment on the article by Kuwahara et al, published in the recent issue of the World Journal of Cardiology. In this interesting paper, the authors showed a correlation between portal vein pulsatility ratio, examined by bedside ultrasonography, and prognosis of hospitalized patients with acute heart failure. Systemic congestion is being notoriously underdetected in the acutely ill population with conventional methods like clinical examination, biomarkers, central venous pressure estimation and X-rays. However, congestion should be a key therapeutic target due to its deleterious effects to end organ function and subsequently patient prognosis. Doppler flow assessment of the abdominal veins is gaining popularity worldwide, as a valuable tool in estimating comprehensively congestion and giving a further insight into hemodynamics and patient management.

The Portal Venous Pulsatility Index and Main Portal Vein Diameter as Surrogate Markers for Liver Fibrosis in Nonalcoholic Fatty Liver Disease and Metabolic-Dysfunction-Associated Steatotic Liver Disease

(1) Background: Despite numerous noninvasive methods for assessing liver fibrosis, effective ultrasound parameters remain limited. We aimed to identify easily measurable ultrasound parameters capable of predicting liver fibrosis in patients with nonalcoholic fatty liver disease (NAFLD) and metabolic-dysfunction-associated steatotic liver disease (MASLD); (2) Methods: The data of 994 patients diagnosed with NAFLD via ultrasound at the Armed Forces Goyang Hospital were retrospectively collected from June 2022 to July 2023. A liver stiffness measurement (LSM) ≥ 8.2 kPa was classified as significant fibrosis. Liver steatosis with cardiometabolic risk factors was defined as MASLD. Two ultrasound variables, the portal venous pulsatility index (VPI) and main portal vein diameter (MPVD), were measured; (3) Results: Of 994 patients, 68 had significant fibrosis. Significant differences in VPI (0.27 vs. 0.34, p < 0.001) and MPVD (10.16 mm vs. 8.98 mm, p < 0.001) were observed between the fibrotic and non-fibrotic groups. A logistic analysis adjusted for age and body mass index (BMI) revealed that only VPI (OR of 0.955, p = 0.022, VPI on a 0.01 scale) and MPVD (OR of 1.501, p < 0.001) were significantly associated with significant liver fibrosis. In the MASLD cohort (n = 939), VPI and MPVD were associated with significant fibrosis. To achieve better accuracy in predicting liver fibrosis, we established a nomogram that incorporated MPVD and VPI. The established nomogram was validated in the test cohort, yielding an area under the receiver operating characteristic curve of 0.821 for detecting significant liver fibrosis; (4) Conclusions: VPI and MPVD, as possible surrogate markers, are useful in predicting significant fibrosis in patients with NAFLD and MASLD.

No need for fasting prior to doppler ultrasound of pediatric liver transplants: A self-controlled study

BACKGROUND

Children frequently undergo routine Doppler-ultrasound (DUS) after liver transplantation (LT) for which they are fasted, but this may cause hunger and discomfort.

OBJECTIVE

To determine if DUS measurements, with focus on the portal vein (PV), are affected by prandial changes, and if this affects distress and feasibility of the DUS.

MATERIALS AND METHODS

Children were prospectively included to undergo a pre- and postprandial DUS on the same day at 6 months after LT. Pre- and anastomotic PV peak systolic velocity (PSV), and hepatic artery and hepatic vein DUS measurements were obtained. Pre- and postprandial measurements, and relative postprandial change of PV velocity ratio (VR) compared to PV anastomotic PSV, were compared using paired-sample t-tests and intraclass correlation coefficients (ICC). Obscuration by bowel gas, difficulty of DUS, and impact of fasting were assessed using 5-point rating scales.

RESULTS

Twenty-eight children (median age 3.5 years, IQR 1.6-10.8) were included; four were subsequently excluded because they were not fasted (N = 2) or withdrew consent for the second DUS (N = 2). Measurements between pre- and postprandial DUS, and relative postprandial change of VR compared to PV anastomotic PSV, were not significantly different (p > .05). Test consistency was good (ICC = 0.69, 95% CI = 0.29-0.67) for PV anastomotic PSV, and excellent (95% CI = 0.61-0.93) for PV VR. Obscuration by bowel gas or ease of DUS did not change after eating (p > .05). The majority (16/28, 57.2%) found fasting difficult, and several (13/28, 46.4%) got upset when fasted.

CONCLUSION

Children with an LT do not need to be fasted for routine DUS, which may decrease the burden of the examination.

Cornelian Cherry (Cornus mas L.) Fruit Extract Lowers SREBP-1c and C/EBPα in Liver and Alters Various PPAR-α, PPAR-γ, LXR-α Target Genes in Cholesterol-Rich Diet Rabbit Model

Cornelian cherry (Cornus mas L.) fruits, abundant in iridoids and anthocyanins, are natural products with proven beneficial impacts on the functions of the cardiovascular system and the liver. This study aims to assess and compare whether and to what extent two different doses of resin-purified cornelian cherry extract (10 mg/kg b.w. or 50 mg/kg b.w.) applied in a cholesterol-rich diet rabbit model affect the levels of sterol regulatory element-binding protein 1c (SREBP-1c) and CCAAT/enhancer binding protein α (C/EBPα), and various liver X receptor-α (LXR-α), peroxisome proliferator-activated receptor-α (PPAR-α), and peroxisome proliferator-activated receptor-γ (PPAR-γ) target genes. Moreover, the aim is to evaluate the resistive index (RI) of common carotid arteries (CCAs) and aortas, and histopathological changes in CCAs. For this purpose, the levels of SREBP-1c, C/EBPα, ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette transporter G1 (ABCG1), fatty acid synthase (FAS), endothelial lipase (LIPG), carnitine palmitoyltransferase 1A (CPT1A), and adiponectin receptor 2 (AdipoR2) in liver tissue were measured. Also, the levels of lipoprotein lipase (LPL), visceral adipose tissue-derived serine protease inhibitor (Vaspin), and retinol-binding protein 4 (RBP4) in visceral adipose tissue were measured. The RI of CCAs and aortas, and histopathological changes in CCAs, were indicated. The oral administration of the cornelian cherry extract decreased the SREBP-1c and C/EBPα in both doses. The dose of 10 mg/kg b.w. increased ABCA1 and decreased FAS, CPT1A, and RBP4, and the dose of 50 mg/kg b.w. enhanced ABCG1 and AdipoR2. Mitigations in atheromatous changes in rabbits' CCAs were also observed. The obtained outcomes were compared to the results of our previous works. The beneficial results confirm that cornelian cherry fruit extract may constitute a potentially effective product in the prevention and treatment of obesity-related disorders.

Utility of portal vein pulsatility fraction in patients undergoing corrective surgery for tetralogy of Fallot

BACKGROUND

Right ventricle dysfunction is common after corrective surgery for tetralogy of Fallot and is associated with significant morbidity and mortality. We aimed to determine whether an increased portal vein pulsatility fraction (PVPF) was associated with worse clinical outcomes.

METHODS

In a prospective, observational, single-centre study, PVPF and other commonly used parameters of right ventricle function were assessed in patients of all ages undergoing corrective surgery for tetralogy of Fallot intraoperatively, with transesophageal echocardiography, before and after bypass, and post-operatively, with transthoracic echocardiography, at days 1, 2, at extubation, and at ICU discharge. The correlation was tested between PVPF and mechanical ventilation duration, prolonged ICU stay, mortality, and right ventricle function.

RESULTS

The study included 52 patients, and mortality was in 3 patients. PVPF measurement was feasible in 96% of the examinations. PVPF in the immediate post-operative period had sensitivity of 73.3% and a specificity of 74.3% in predicting the occurrence of the composite outcome of prolonged mechanical ventilation, ICU stay, or mortality. There was a moderate negative correlation of PVPF with right ventricle fractional area change and right ventricle global longitudinal strain (r = -0.577, p < 0.001 and r = 0.465, p < 0.001, respectively) and a strong positive correlation with abnormal hepatic vein waveform (rho = 0.749, p < 0.001).

CONCLUSION

PVPF is an easily obtainable bedside parameter to assess right ventricular dysfunction and predict prolonged mechanical ventilation, prolonged ICU stay, and mortality.

Colour Doppler study of blood flow in the portal vein in relation to blood flow in the milk vein, milk yield and body condition of dairy cows during dry period and lactation

In dairy cows, the liver supports the increased nutrient demands of the udder for milk production. Blood flow is key for the transport of these nutrients. This study investigated portal vein blood flow volume (PVBFVol) in relation to daily milk yield (DMY), milk vein blood flow volume (MVBFVol) and body condition parameters of high-producing dairy cows, starting from late lactation, throughout dry period, and consecutive early lactation. Seventeen repeated examinations were performed on 19 Holstein cows and 313 measurement days were finally included. Vein morphology and blood flow were examined via B-mode and spectral Doppler (triplex) ultrasonography, respectively. Body condition parameters recorded were body condition score (BCS), backfat thickness (BFT) measurement with ultrasonography, heart girth circumference (HG) and withers height (WH). Longitudinal relationship of PVBFVol with MVBFVol, DMY, BCS, BFT, HG and WH was analyzed with linear mixed models, with random intercept effects, using restricted cubic splines. A significant increase of 8.28% (p < 0.01) in PVBFVol appeared for every 1 L/min increase in MVBFVol in the univariable model. PVBFVol presented a significant negative association with BCS (p < 0.01) and BFT (p = 0.02), while interaction with production stage was significant, too. PVBFVol significantly increased by 0.38% (p = 0.04) for every 1 kg increase in DMY in the multivariable model. In conclusion, the increased PVBFVol during lactation accompanies the escalation in metabolic activity of the liver and the increased blood circulation through the udder, coping with the udder's escalating nutrient demands for milk synthesis.

Imaging of Uterine Transplantation

Uterus transplantation (UTx) is a novel procedure being studied as a treatment of absolute uterine factor infertility. Imaging plays an important role throughout the life cycle of a uterus transplant. In this review, we will first describe the surgical technique of UTx. The article will then focus on the importance of imaging in the evaluation of potential recipients and donors and during the immediate post-surgical time course as graft viability is established. Imaging as part of including in vitro fertilization, pregnancy, and complications will also be discussed.

Doppler-ultrasound reference values after pediatric liver transplantation: a consecutive cohort study

OBJECTIVES

Doppler ultrasound (DUS) is the main imaging modality to evaluate vascular complications of pediatric liver transplants (LT). The current study aimed to determine reference values and their change over time.

METHODS

A consecutive cohort of pediatric patients undergoing an LT were retrospectively included between 2015 and 2020. Timepoints for standardized DUS were intra-operative and postoperative (day 0), days 1-7, months 1 and 3, and years 1 and 2. DUS measurements of the hepatic artery (HA), portal vein (PV), and hepatic vein(s) (HV) were included if there were no complications during 2 years follow-up. Measurements consisted of: peak systolic velocity (PSV) and resistive index (RI) for the HA, PSV for the PV, and venous pulsatility index (VPI) for the HV. Generalized estimating equations were used to analyze change over time.

RESULTS

One hundred twelve pediatric patients with 123 LTs were included (median age 3.3 years, interquartile range 0.7-10.1). Ninety-five HAs, 100 PVs, and 115 HVs without complications were included. Reference values for HA PSV and RI, PV PSV, and HV VPI were obtained for all timepoints (4043 included data points in total) and presented using 5th-95th percentiles and threshold values. All reference values changed significantly over time (p = 0.032 to p < 0.001).

CONCLUSIONS

DUS reference values of hepatic vessels in children after LT are presented, reference values change over time with specific vessel-dependent patterns. Timepoint-specific reference values improve the interpretation of DUS values and may help to better weigh their clinical significance.

KEY POINTS

• Doppler ultrasound reference values of pediatric liver transplantations are not static but change over time. Applying the correct reference values for the specific timepoint may further improve the interpretation of the measurements. • The pattern of change over time of Doppler ultrasound measurements differs between the hepatic vessel and measurement; knowledge of these patterns may help radiologists to better understand normal postoperative hemodynamic changes.

Assessing Enhanced Acoustic Absorption From Sonosensitive Perfluorocarbon Emulsion With Magnetic Resonance-Guided High-Intensity Focused Ultrasound and a Percolated Tissue-Mimicking Flow Phantom

OBJECTIVE

Sonosensitive high-boiling point perfluorocarbon F₈TAC₁₈-PFOB emulsions previously exhibited thermal enhancement during focused ultrasound heating in ex vivo pig livers, kidneys and a laminar flow phantom. The main objectives of this study were to evaluate heating under turbulent conditions, observe perfusion effects, quantify heating in terms of acoustic absorption and model the experimental data.

METHODS

In this study, similar perfluorocarbon emulsions were circulated at incremental concentrations of 0.07, 0.13, 0.19 and 0.25% v:v through a percolated turbulent flow phantom, more representative of the biological tissue than a laminar flow phantom. The concentrations represent the droplet content in only the perfused fluid, rather than the droplet concentration throughout the entire cross-section. The temperature was measured with magnetic resonance thermometry, during focused ultrasound sonications of 67 W, 95% duty cycle and 33 s duration. These were used in Bioheat equation simulations to investigate in silico the thermal phenomena. The temperature change was compared with the control condition by circulating de-gassed and de-ionized water through the flow phantom without droplets.

RESULTS

With these 1.24 µm diameter droplets at 0.25% v:v, the acoustic absorption coefficient increased from 0.93 ± 0.05 at 0.0% v:v to 1.82 ± 0.22 m^-1 at 0.25% v:v using a 0.1 mL s^-1 flow rate. Without perfusion at 0.25% v:v, an increase was observed from 1.23 ± 0.07 m^-1 at 0.0% v:v to 1.65 ± 0.17 m^-1.

CONCLUSION

The results further support previously reported thermal enhancement with F₈TAC₁₈-PFOB emulsion, quantified the increased absorption at small concentration intervals, illustrated that the effects can be observed in a variety of visceral tissue models and provided a method to simulate untested scenarios.

Hepatic Venous Stasis Index Reflects Hepatic Congestion and Predicts Adverse Outcomes in Patients With Heart Failure

Background It has been reported that the hepatic vein waveforms determined by abdominal ultrasonography can assess hepatic congestion in patients with heart failure (HF). However, the parameter that quantifies hepatic vein waveforms has not been established. We suggest the hepatic venous stasis index (HVSI) as the novel indicator to evaluate hepatic congestion quantitatively. To examine the clinical significance of HVSI in patients with HF, we aimed to clarify the associations of HVSI with the parameters of cardiac function and right heart catheterization, as well as that with prognosis, in patients with HF. Methods and Results We performed abdominal ultrasonography, echocardiography, and right heart catheterization in patients with HF (n=513). The patients were divided into 3 groups based on HVSI as follows: HVSI 0 (HVSI=0, n=253), low HVSI (HVSI 0.01-0.20, n=132), and high HVSI (HVSI>0.20, n=128). We examined the associations of HVSI with parameters of cardiac function and right heart catheterization and followed up for cardiac events defined as cardiac death or worsening HF. There was a significant increase in level of B-type natriuretic peptide, inferior vena cava diameter, and mean right atrial pressure with increasing HVSI. During the follow-up period, cardiac events occurred in 87 patients. In the Kaplan-Meier analysis, cardiac event rate increased across increasing HVSI (log-rank, P=0.002). Conclusions HVSI assessed by abdominal ultrasonography reflects hepatic congestion and right-sided HF and is associated with adverse prognosis in patients with HF.

Portal vein congestion index in patients with and without chronic liver disease

Aim of the study

Portal vein congestion index has shown promise in detecting early portal venous hemodynamic changes in chronic liver disease. The aim of this study was to compare the portal vein congestion index of adult patients with chronic liver disease to that of healthy controls, and to evaluate the differences in portal vein congestion index, if any, between the common etiologies of chronic liver disease (chronic viral hepatitis, alcoholic liver disease, and non-alcoholic fatty liver disease).

Method and materials

Eighty participants with chronic liver disease and 80 healthy controls had their sociodemographic variables, anthropometric indices, liver size/echotexture, spleen size, presence of ascites, and portal vein parameters (diameter, cross-sectional area, velocity, and congestion index) evaluated. P ≤0.05 was considered statistically significant.

Results

There were 48 (60%) males and 32 (40%) females in the control group, while 56 (70%) males and 24 (30%) females were included in the chronic liver disease group (p = 0.185). Of the eighty people with chronic liver disease, 57 (71.2%) were diagnosed with alcoholic liver disease, while 23 (28.8%) were diagnosed with chronic viral hepatitis. There were no cases of non-alcoholic fatty liver disease during the study period. The mean liver spans of the control and chronic liver disease groups were 13.45 ± 0.85 cm and 16.50 ± 4.96 cm, respectively. All the controls had normal hepatic parenchymal echogenicity, while 45 (56.3%) subjects with chronic liver disease (36 alcoholic liver disease and 9 chronic viral hepatitis) had increased hepatic echogenicity. The mean values of the portal vein congestion index for the control and chronic liver disease groups were 0.0775 ± 0.02 cm/sec and 0.1037 ± 0.03 cm/sec, respectively (p <0.0001).

Conclusion

The chronic liver disease group showed a significantly higher mean portal vein congestion index than the control group.

Effect of Hepatic Pathology on Liver Regeneration: The Main Metabolic Mechanisms Causing Impaired Hepatic Regeneration

Liver regeneration has been studied for many decades, and the mechanisms underlying regeneration of normal liver following resection are well described. However, no less relevant is the study of mechanisms that disrupt the process of liver regeneration. First of all, a violation of liver regeneration can occur in the presence of concomitant hepatic pathology, which is a key factor reducing the liver's regenerative potential. Understanding these mechanisms could enable the rational targeting of specific therapies to either reduce the factors inhibiting regeneration or to directly stimulate liver regeneration. This review describes the known mechanisms of normal liver regeneration and factors that reduce its regenerative potential, primarily at the level of hepatocyte metabolism, in the presence of concomitant hepatic pathology. We also briefly discuss promising strategies for stimulating liver regeneration and those concerning methods for assessing the regenerative potential of the liver, especially intraoperatively.

Hepatic artery and portal vein Doppler ultrasound reference values in children aged 0-17 years old

Introduction

Doppler ultrasound of the portal vein peak systolic velocity and hepatic artery peak systolic velocity and resistive index in children is often performed during abdominal ultrasound for the assessment of liver and other abdominal pathology. However, evidence-based reference values are not available. We aimed to determine these reference values and to investigate whether they are age-dependent.

Methods

Children who underwent abdominal ultrasound between 2020 and 2021 were retrospectively identified. Patients without hepatic or cardiac abnormalities at the time of ultrasound or during at least 3 months follow-up were eligible for the study. Ultrasound without hepatic hilum portal vein peak systolic velocity and/or hepatic artery peak systolic velocity and resistive index measurements were excluded. Age-dependent changes were analyzed using linear regression. Normal range reference values were described using percentiles for all ages, and for age subgroups.

Results

One-hundred ultrasound examinations performed in 100 healthy children aged 0-17.9 years (median 7.8 years, interquartile range 1.1-14.1 years) were included. Ninety-nine portal vein peak systolic velocity and 80 hepatic artery peak systolic velocity and resistive index measurements were obtained. There was no significant association between portal vein peak systolic velocity and age (β = -0.056, p = 0.68). There were significant associations between age and hepatic artery peak systolic velocity, and between age and hepatic artery resistive index (β = -0.873, p = 0.04 and β = -0.004, p < 0.001, respectively). Detailed reference values were provided for all ages, and for age subgroups.

Conclusion

Reference values for the hepatic hilum portal vein peak systolic velocity, hepatic artery peak systolic velocity, and hepatic artery resistive index in children were established. Portal vein peak systolic velocity is not age-dependent, whereas hepatic artery peak systolic velocity and hepatic artery resistive index decrease when children get older.

Evaluation of Portal, Splenic, and Hepatic Vein Flows in Children Undergoing Congenital Heart Surgery

OBJECTIVE

Little is known about changes in portal, splenic, and hepatic vein flow patterns in children undergoing congenital heart surgery. This study aimed to determine the characteristics of portal, splenic, and hepatic vein flow patterns using ultrasonography in children undergoing cardiac surgery.

DESIGN

Single-center, prospective observational study.

SETTING

Tertiary children's hospital, operating room.

PARTICIPANTS

Children undergoing cardiac surgery.

MEASUREMENT AND MAIN RESULTS

The authors obtained ultrasound data from the heart, inferior vena cava, portal, splenic, and hepatic veins before and after surgeries. In the biventricular group, which included children with atrial and ventricular septal defects and pulmonary stenosis (n = 246), the portal pulsatility index decreased from 38.7% to 25.6% (p < 0.001) after surgery. The preoperative portal pulsatility index was significantly higher in patients with pulmonary hypertension (43.3% v 27.4%; p < 0.001). In the single-ventricle group (n = 77), maximum portal vein flow velocities of Fontan patients were significantly lower (13.5 cm/s) compared with that of patients with modified Blalock-Taussig shunt (19.7 cm/s; p = 0.035) or bidirectional cavopulmonary shunt (23.1 cm/s; p < 0.001). The cardiac index was inversely correlated with the portal pulsatility index in the bidirectional cavopulmonary shunt and Fontan circulation. (β = -5.693, r² = 0.473; p = 0.001) The portal pulsatility index was correlated with splenic venous pulsatility and hepatic venous atrial reverse flow velocity in biventricular and single-ventricle groups.

CONCLUSIONS

The characteristics of venous Doppler patterns in the portal, splenic, and hepatic veins differed according to congenital heart disease. Further studies are required to determine the association between splanchnic venous Doppler findings and clinical outcomes in this population.

Population pharmacokinetics of sublingually administered tacrolimus in infants and young children with liver transplantation

AIMS

Pharmacokinetics of tacrolimus after sublingual administration is not characterized in paediatric liver transplant patients. Therefore, we aimed to develop a population pharmacokinetic model of sublingually administered tacrolimus in patients who cannot swallow the capsules due to their age, sedation status and/or mechanical ventilation during the first weeks post-transplantation.

METHODS

Demographic, clinical and pharmacological variables, including tacrolimus whole blood concentrations obtained from therapeutic drug monitoring and data from dense-sampling pharmacokinetic profiles, were recorded in 26 paediatric patients with biliary atresia who underwent liver transplantation between 2016 and 2021. Population pharmacokinetic analysis was performed with NONMEM v7.4.

RESULTS

Disposition of tacrolimus was best characterized by a 2-compartment model with clearance achieving half of the maximum elimination capacity (CL_MAX  = 4.1 L/h) at 4.6 days post-transplantation (T₅₀ ). Compared to sedated patients, nonsedated status showed an increased first-order absorption rate constant (1.1 vs. 0.1 h^-1 ) and a 24% reduction in bioavailability (F_NS ) at 14 days post-transplant. The model was able to explain the oral absorption pattern in nonsedated patients as the result of gut bioavailability (0.9) and hepatic extraction ratio, with the latter being responsible for first-pass effects. Estimates of interindividual variability remained moderate (25.9% for the gut bioavailability) to high (79.8% for the apparent volume of distribution of the central compartment, and 101% for T₅₀ ).

CONCLUSION

A population pharmacokinetic model of sublingually administered tacrolimus in paediatric patients was developed to characterize different absorption mechanisms. Once the model is externally validated, the effect of post-transplant time on clearance and the sedation status may be considered in routine dosing management.

Imaging Features of Main Hepatic Resections: The Radiologist Challenging

Liver resection is still the most effective treatment of primary liver malignancies, including hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), and of metastatic disease, such as colorectal liver metastases. The type of liver resection (anatomic versus non anatomic resection) depends on different features, mainly on the type of malignancy (primary liver neoplasm versus metastatic lesion), size of tumor, its relation with blood and biliary vessels, and the volume of future liver remnant (FLT). Imaging plays a critical role in postoperative assessment, offering the possibility to recognize normal postoperative findings and potential complications. Ultrasonography (US) is the first-line diagnostic tool to use in post-surgical phase. However, computed tomography (CT), due to its comprehensive assessment, allows for a more accurate evaluation and more normal findings than the possible postoperative complications. Magnetic resonance imaging (MRI) with cholangiopancreatography (MRCP) and/or hepatospecific contrast agents remains the best tool for bile duct injuries diagnosis and for ischemic cholangitis evaluation. Consequently, radiologists should be familiar with the surgical approaches for a better comprehension of normal postoperative findings and of postoperative complications.

Prevalence of extra-hepatic incidental findings on ultrasound screening for hepatocellular carcinoma

PURPOSE

Abdominal ultrasound is a cost-effective method for screening for hepatocellular carcinoma (HCC) in high-risk individuals. Currently, at many institutions the protocol for obtaining HCC screening ultrasounds includes a traditional examination of the right upper quadrant, including the pancreas and right kidney. There is no consensus on the role of imaging of extra-hepatic structures and there are limited data describing the frequency and clinical significance of incidental findings discovered during HCC screening. The purpose of this retrospective study is to assess the prevalence and significance of extra-hepatic incidental findings during HCC screening ultrasounds.

METHODS

A single-center retrospective review of all right upper quadrant HCC screening ultrasounds identified 432 HCC screening ultrasounds performed on 294 adults over a 2.5-year period. Findings in all organs evaluated were recorded. Any incidental finding was classified as minor, moderate, or major clinical significance.

RESULTS

At least one extra-hepatic finding was documented in 57.4% of examinations. The most common extra-hepatic findings occurred in the gallbladder (40.3%), most commonly gallstones (25.4%). Four moderate clinically significant incidental findings were recorded (0.9%). Only one of these incidental findings required specific imaging follow up (0.2%). No major clinical significance incidental findings were identified.

CONCLUSIONS

Potentially clinically significant incidental findings during ultrasound HCC screenings are rare. Incidental findings identified on HCC screening did not result in significant additional follow-up imaging or interventions.

Clinical Outcomes and Patency after Transjugular Intrahepatic Portosystemic Shunt Reduction for Overshunting Adverse Events

PURPOSE

To assess clinical outcomes and patency after transjugular intrahepatic portosystemic shunt (TIPS) reduction for overshunting adverse events.

MATERIALS AND METHODS

This multicenter, retrospective observational study included 33 patients (male-to-female ratio, 20:13; mean age, 59 years; mean Model for End-Stage Liver Disease [MELD] score, 15) who underwent TIPS reduction between 2007 and 2020. Procedure indications included medically refractory hepatic encephalopathy (HE) (85%), post-TIPS hepatic insufficiency (HI) (12%), and heart failure (3%). The measured outcomes included improvement in HE (classified using the West Haven system) and HI, patency of reduced TIPS, and transplant-free survival (TFS).

RESULTS

TIPS reductions were successfully performed using parallel stent (94%) or other (6%) techniques at a median of 120 days after TIPS creation (HE, median, 164 days; HI, median, 5 days). The portosystemic pressure gradient increased from a mean of 10 to 17 mm Hg (P < .001). The overall HE rate after TIPS reduction was 54%; HE was persistent, improved, and resolved in 21%, 32%, and 46% cases, respectively. In patients with HI, the MELD score increased from a mean of 22 before TIPS to 34 after TIPS (P = .061), but without improvement (0%) in HI after TIPS reduction (mean MELD score, 30; P = .266). Recurrent ascites occurred in 14% of the patients. The median shunt patency was 961 days (95% confidence interval, 476-1,447). The 30-day, 6-month, 1-year, and 3-year shunt patency rates were 92%, 81%, 74%, and 37%, respectively. The median TFS was not reached. The 30-day, 6-month, 1-year, and 3-year survival rates were 97%, 90%, 81%, and 60%, respectively.

CONCLUSIONS

Although TIPS reduction may be an effective and durable approach to treat post-TIPS medically refractory HE, shunt reduction may not achieve meaningful benefit for HI.

Abdominal Vascular Evaluation

The vascular lab (VL) is instrumental in diagnosing vascular diseases such as renal artery stenosis and mesenteric ischemia or following a patient after transjugular intrahepatic portal systemic shunt (TIPS) creation. This article discusses indications, protocol, and diagnostic criteria for abdominal vascular ultrasound. The vascular lab can be used to investigate pathology in the abdomen either as a preliminary screening tool to evaluate for a pathology such as mesenteric artery stenosis in a patient with food fear and weight loss, renal artery stenosis in a patient with refractory hypertension or renal failure, or as a diagnostic tool in follow up after a patient has undergone a transjugular intrahepatic portal systemic shunt (TIPS) for portal hypertension. The technical success of duplex ultrasonography of the abdomen can be compromised by respiratory motion, obesity, and intestinal gas. Therefore, duplex scanning is performed in the fasting state particularly in elective outpatient cases. In emergent cases when pathology such as acute mesenteric ischemia is suspected evaluation with CT angiography may be best.

A Review of Blood-mimicking Fluid Properties Using Doppler Ultrasound Applications

Doppler imaging ultrasound characterization and standardization requires blood that is called blood mimicking fluid for the exam. With recognized internal properties, acoustic and physical features of this artificial blood. Both acoustical and physical merits set in the International Electrotechnical Commission (IEC) scale are determined as regular values, where the components utilized in the artificial blood preparation must have values identical to the IEC values. An artificial blood is commercially available in the medical application and may not be suitable in the mode of ultrasonic device or for rate of new imaging technique. It is sometimes qualified to have the strength to produce sound features and simulate blood configuration for particular implementations. In the current review article, appropriate artificial blood components, fluids, and measurements are described that have been created using varied materials and processes that have modified for medical applications.

Abdominal applications of quantitative 4D flow MRI

4D flow MRI is a quantitative MRI technique that allows the comprehensive assessment of time-resolved hemodynamics and vascular anatomy over a 3-dimensional imaging volume. It effectively combines several advantages of invasive and non-invasive imaging modalities like ultrasound, angiography, and computed tomography in a single MRI acquisition and provides an unprecedented characterization of velocity fields acquired non-invasively in vivo. Functional and morphological imaging of the abdominal vasculature is especially challenging due to its complex and variable anatomy with a wide range of vessel calibers and flow velocities and the need for large volumetric coverage. Despite these challenges, 4D flow MRI is a promising diagnostic and prognostic tool as many pathologies in the abdomen are associated with changes of either hemodynamics or morphology of arteries, veins, or the portal venous system. In this review article, we will discuss technical aspects of the implementation of abdominal 4D flow MRI ranging from patient preparation and acquisition protocol over post-processing and quality control to final data analysis. In recent years, the range of applications for 4D flow in the abdomen has increased profoundly. Therefore, we will review potential clinical applications and address their clinical importance, relevant quantitative and qualitative parameters, and unmet challenges.

The Role of Imaging in Peripheral Interventions

Patient evaluation is critical to identify and quantitate patient's disease. Aside from the patient's history and physical examination, imaging can help confirm and determine the extent of disease. Imaging can aid in treatment planning once the decision to proceed to intervention has been made. This chapter will discuss the role of imaging before and after peripheral arterial interventions and how it may improve intervention outcomes. It will discuss the value of the arterial noninvasive examinations (ankle-brachial index, toe-brachial index, pulse volume recordings, and arterial duplex ultrasound), computed tomographic angiograms, magnetic resonance angiogram, and intravascular ultrasound.

Characterization of Doppler spectrum of hepatic veins in dogs with pulmonary hypertension

Pulmonary hypertension (PH) triggers hemodynamic changes within the right heart, which may affect hepatic venous flow. The aims of this study were three-fold: to investigate, prospectively, the reliability of the hepatic vein Doppler waveform to diagnose and characterize the magnitude of PH in dogs; to evaluate whether a correlation exists between hepatic venous flow waves and the structural and functional characteristics of the right ventricle (RV); and to determine whether age, gender, body weight, heart rate (HR), heart rhythm and systolic blood pressure affect the hepatic venous waveform pattern. A cross-sectional observational study was carried out in 43 dogs with varying degrees of PH and a control group of 15 healthy dogs. The velocities of the hepatic A, S, V and D spectral waves and the phasic pattern varied according to the severity of PH. Weak to moderate correlations were documented between hepatic vein waves and age, HR, and the structural and functional variables of the RV. A D Wave cut-off of 11.6 cm ∙ s-1 had a sensitivity of 100% and specificity of 35% for differentiation of dogs with severe PH from healthy dogs. Doppler assessment of hepatic venous flow was shown to be a reliable technique for screening dogs for PH.

Assessment of hepatic arterial hemodynamics with 4D flow MRI: in vitro analysis of motion and spatial resolution related error and in vivo feasibility study in 20 volunteers

OBJECTIVES

To assess the ability of four-dimensional (4D) flow MRI to measure hepatic arterial hemodynamics by determining the effects of spatial resolution and respiratory motion suppression in vitro and its applicability in vivo with comparison to two-dimensional (2D) phase-contrast MRI.

METHODS

A dynamic hepatic artery phantom and 20 consecutive volunteers were scanned. The accuracies of Cartesian 4D flow sequences with k-space reordering and navigator gating at four spatial resolutions (0.5- to 1-mm isotropic) and navigator acceptance windows (± 8 to ± 2 mm) and one 2D phase-contrast sequence (0.5-mm in -plane) were assessed in vitro at 3 T. Two sequences centered on gastroduodenal and hepatic artery branches were assessed in vivo for intra - and interobserver agreement and compared to 2D phase-contrast.

RESULTS

In vitro, higher spatial resolution led to a greater decrease in error than narrower navigator window (30.5 to -4.67% vs -6.64 to -4.67% for flow). In vivo, hepatic and gastroduodenal arteries were more often visualized with the higher resolution sequence (90 vs 71%). Despite similar interobserver agreement (κ = 0.660 and 0.704), the higher resolution sequence had lower variability for area (CV = 20.04 vs 30.67%), flow (CV = 34.92 vs 51.99%), and average velocity (CV = 26.47 vs 44.76%). 4D flow had lower differences between inflow and outflow at the hepatic artery bifurcation (11.03 ± 5.05% and 15.69 ± 6.14%) than 2D phase-contrast (28.77 ± 21.01%).

CONCLUSION

High-resolution 4D flow can assess hepatic artery anatomy and hemodynamics with improved accuracy, greater vessel visibility, better interobserver reliability, and internal consistency.

KEY POINTS

• Motion-suppressed Cartesian four-dimensional (4D) flow MRI with higher spatial resolution provides more accurate measurements even when accepted respiratory motion exceeds voxel size. • 4D flow MRI with higher spatial resolution provides substantial interobserver agreement for visualization of hepatic artery branches. • Lower peak and average velocities and a trend toward better internal consistency were observed with 4D flow MRI as compared to 2D phase-contrast.

Imaging Features of Main Posthepatectomy Complications: A Radiologist’s Challenge

In the recent years, the number of liver resections has seen an impressive growth. Usually, hepatic resections remain the treatment of various liver diseases, such as malignant tumors, benign tumors, hydatid disease, and abscesses. Despite technical advancements and tremendous experience in the field of liver resection of specialized centers, there are moderately high rates of postoperative morbidity and mortality, especially in high-risk and older patient populations. Although ultrasonography is usually the first-line imaging examination for postoperative complications, Computed Tomography (CT) is the imaging tool of choice in emergency settings due to its capability to assess the whole body in a few seconds and detect all possible complications. Magnetic resonance cholangiopancreatography (MRCP) is the imaging modality of choice for delineating early postoperative bile duct injuries and ischemic cholangitis that may arise in the late postoperative phase. Moreover, both MDCT and MRCP can precisely detect tumor recurrence. Consequently, radiologists should have knowledge of these surgical procedures for better comprehension of postoperative changes and recognition of the radiological features of various postoperative complications.

Venous Excess Doppler Ultrasound for the Nephrologist: Pearls and Pitfalls

The role of venous congestion in abnormal kidney function is being increasingly recognized. It is well known that unresolved congestion is associated with adverse kidney and overall outcomes in patients with heart failure. Similarly, any condition that leads to elevated central venous pressure, such as pulmonary hypertension, can result in impaired kidney perfusion by increasing its afterload. Point-of-care ultrasonography (POCUS) enables the clinician to objectively assess hemodynamics at the bedside and, thereby, guide patient management. Lung POCUS has received widespread attention in the recent past because of the relative ease of the technique, but it reflects only left heart pressures and not venous congestion. Although inferior vena cava POCUS is used to estimate right atrial pressure, its isolated use cannot demonstrate organ congestion. Moreover, it is associated with several technical and conceptual limitations. Recently, venous excess Doppler ultrasound has emerged as a tool to assess venous congestion at the organ level in real time. Severe flow abnormalities in hepatic, portal, and kidney parenchymal veins have shown to predict the risk of congestive kidney injury. In addition, it helps to objectively monitor the efficacy of decongestive therapy. In this review, we provide a brief overview of various components of venous excess Doppler ultrasound and share our perspective on incorporating this novel tool in nephrology practice.

Clinical Applications of 4D Flow MRI in the Portal Venous System

Evaluation of the hemodynamics in the portal venous system plays an essential role in many hepatic pathologies. Changes in portal flow and vessel morphology are often indicative of disease.Routinely used imaging modalities, such as CT, ultrasound, invasive angiography, and MRI, often focus on either hemodynamics or anatomical imaging. In contrast, 4D flow MRI facilitiates a more comprehensive understanding of pathophysiological mechanisms by simultaneously and noninvasively acquiring time-resolved flow and anatomical information in a 3D imaging volume.Though promising, 4D flow MRI in the portal venous system is especially challenging due to small vessel calibers, slow flow velocities, and breathing motion. In this review article, we will discuss how to account for these challenges when planning and conducting 4D flow MRI acquisitions in the upper abdomen. We will address patient preparation, sequence acquisition, postprocessing, quality control, and analysis of 4D flow data.In the second part of this article, we will review potential clinical applications of 4D flow MRI in the portal venous system. The most promising area for clinical utilization is the diagnosis and grading of liver cirrhosis and its complications. Relevant parameters acquired by 4D flow MRI include the detection of reduced or reversed flow in the portal venous system, characterization of portosystemic collaterals, and impaired response to a meal challenge. In patients with cirrhosis, 4D flow MRI has the potential to address the major unmet need of noninvasive detection of gastroesophageal varices at high risk for bleeding. This could replace many unnecessary, purely diagnostic, and invasive esophagogastroduodenoscopy procedures, thereby improving patient compliance with follow-up. Moreover, 4D flow MRI offers unique insights and added value for surgical planning and follow-up of multiple hepatic interventions, including transjugular intrahepatic portosystemic shunts, liver transplantation, and hepatic disease in children. Lastly, we will discuss the path to clinical implementation and remaining challenges.

Assessing Fluid Intolerance with Doppler Ultrasonography: A Physiological Framework

Ultrasonography is becoming the favored hemodynamic monitoring utensil of emergentologists, anesthesiologists and intensivists. While the roles of ultrasound grow and evolve, many clinical applications of ultrasound stem from qualitative, image-based protocols, especially for diagnosing and managing circulatory failure. Often, these algorithms imply or suggest treatment. For example, intravenous fluids are opted for or against based upon ultrasonographic signs of preload and estimation of the left ventricular ejection fraction. Though appealing, image-based algorithms skirt some foundational tenets of cardiac physiology; namely, (1) the relationship between cardiac filling and stroke volume varies considerably in the critically ill, (2) the correlation between cardiac filling and total vascular volume is poor and (3) the ejection fraction is not purely an appraisal of cardiac function but rather a measure of coupling between the ventricle and the arterial load. Therefore, management decisions could be enhanced by quantitative approaches, enabled by Doppler ultrasonography. Both fluid ‘responsiveness’ and ‘tolerance’ are evaluated by Doppler ultrasound, but the physiological relationship between these constructs is nebulous. Accordingly, it is argued that the link between them is founded upon the Frank–Starling–Sarnoff relationship and that this framework helps direct future ultrasound protocols, explains seemingly discordant findings and steers new routes of enquiry.

Application of POCUS in patients with COVID-19 for acute respiratory distress syndrome management: a narrative review

COVID-19 has inflicted the world for over two years. The recent mutant virus strains pose greater challenges to disease prevention and treatment. COVID-19 can cause acute respiratory distress syndrome (ARDS) and extrapulmonary injury. Dynamic monitoring of each patient's condition is necessary to timely tailor treatments, improve prognosis and reduce mortality. Point-of-care ultrasound (POCUS) is broadly used in patients with ARDS. POCUS is recommended to be performed regularly in COVID-19 patients for respiratory failure management. In this review, we summarized the ultrasound characteristics of COVID-19 patients, mainly focusing on lung ultrasound and echocardiography. Furthermore, we also provided the experience of using POCUS to manage COVID-19-related ARDS.

Clinical-laboratory and ultrasound parallels of changes in the liver and thyroid gland in diffuse toxic goiter

Detection of liver dysfunction in patients with diffuse toxic goiter (DTG) at an early stage allows for correcting it in time with appropriate therapy; therefore, diagnosing hepatobiliary system lesions in these patients is an important medical issue. We examined 62 patients, divided into two groups depending on the duration of the disease. The first group included patients with a disease duration of up to two years, the second group - patients with a disease duration of more than two years. The study and comparison of laboratory and multiparametric ultrasound criteria of liver and thyroid dysfunction were performed. Analysis of ultrasound signs of hepatobiliary system lesions in patients in the two groups showed that they were more common in the second group. There is a correlation between the stiffness of the parenchyma of the thyroid gland and liver and the duration of the disease, the level of free thyroxine (T4f), and antibodies to thyroid-stimulating hormone receptors (ArTTG). Increased liver stiffness was more common in patients with ArTTG levels above 20 IU/ml, and the degree of F1 fibrosis was higher at T4f greater than 50 pmol/l. To assess the condition of a patient with DTG and the need to correct treatment tactics, it is advisable to use the criteria of multiparametric ultrasound examination of the hepatobiliary system and thyroid gland.

Point of care venous Doppler ultrasound: Exploring the missing piece of bedside hemodynamic assessment

Accurate assessment of the hemodynamic status is vital for appropriate management of patients with critical illness. As such, there has been a constant quest for reliable and non-invasive bedside tools to assess and monitor circulatory status in order to ensure end-organ perfusion. In the recent past, point of care ultrasonography (POCUS) has emerged as a valuable adjunct to physical examination in various specialties, which basically is a clinician-performed bedside ultrasound to answer focused questions. POCUS allows visualization of the internal anatomy and flow dynamics in real time, guiding apt interventions. While both arterial (forward flow) and venous (organ outflow or afterload) limbs of hemodynamic circuit are important for tissue perfusion, the venous side remains relatively under-explored. With recent data underscoring the deleterious consequences of iatrogenic volume overload, objective evaluation of venous congestion is gaining attention. Bedside Doppler ultrasound serves this purpose and aids in diagnosing and monitoring the congestion/venous blood flow pattern. In this article, we summarize the rationale for integrating this technology into routine care of patients with volume-related disorders, discuss the normal and abnormal waveforms, limitations, and future directions.

Complications of transjugular intrahepatic portosystemic shunt (TIPS) in the era of the stent graft - What the interventionists need to know?

Transjugular intrahepatic portosystemic shunt (TIPS) is created between a hepatic vein (HV) and the portal vein (PV) to alleviate the symptoms of portal hypertension. Despite high procedural success rates, a myriad of complications may occur at every step of TIPS creation. These complications may be attributable to the procedure itself or the shunt. Portal vein puncture is the most challenging and rate-limiting step, with extrahepatic portal vein puncture being the most devastating tabletop complication. Hepatic encephalopathy is the most common shunt-related complication after TIPS. Unlike bare metallic stents, covered stents have a longer patency rate and lower incidence of TIPS dysfunction. Most of the TIPS dysfunction that occurs with stent-grafts is due to technical errors and mechanical factors. TIPS revision often requires a combination of angioplasty, mechanical thrombectomy, and thrombolytics with a need for additional stenting in some cases. This review article focuses on procedure and shunt-related complications, as well as preventive and management strategies.

Congestive hepatopathy: the role of the radiologist in the diagnosis

The liver has a complex vascularization and is subjected to a high metabolic demand, making it vulnerable to hemodynamic changes. As a result, several pathologies can develop, one of which is congestive hepatopathy. This disease occurs secondary to various cardiovascular conditions that generate a persistent passive venous congestion in the liver, which in the long term can culminate in fibrosis and cirrhosis, which in turn increases the risk of developing hepatocellular carcinoma. In order to avoid this outcome, early diagnosis is crucial; however, both the clinical presentation and laboratory tests are unspecific, and they are only altered in advanced stages of the disease. One form of early detection is through imaging findings, there being various useful modalities such as Doppler ultrasonography (US), computed tomography, and magnetic resonance imaging. The purpose of this article is to detail the imaging findings of congestive hepatopathy in the different available modalities, with special emphasis on Doppler US, highlighting the role of the radiologist in the suspicion of this disease. We summarize the pathophysiologic mechanisms of congestive hepatopathy, clinical findings, and provide description of its main differential diagnoses.

Portal vein thrombosis in patients with chronic liver diseases: From conventional to quantitative imaging

Portal vein thrombosis is a pathological condition characterized by the lumen occlusion of the portal vein and its intrahepatic branches, commonly associated to chronic liver diseases. Portal vein thrombosis is often asymptomatic and discovered as an incidental finding in the follow-up of chronic hepatopathy. Imaging plays a pivotal role in the detection and characterization of portal vein thrombosis in patients with hepatocellular carcinoma. Ultrasound and Color-Doppler ultrasound are usually the first-line imaging modalities for its detection, but they have limits related to operator-experience, patient size, meteorism and the restrained field-of view. Unenhanced cross-sectional imaging doesn't provide specific signs of portal vein thrombosis except under certain specific circumstances. Conventional contrast-enhanced imaging can depict portal vein thrombosis as an endoluminal filling defect best detected in venous phase and can differentiate between non-neoplastic and neoplastic thrombus based on the contrast enhanced uptake, but not always rule-out the malignant nature. Functional and quantitative imaging techniques and software seem to be more accurate. The purpose of this work is to provide the reader with an accurate overview focused on the main imaging features of portal vein thrombosis.

Limited added value of Doppler ultrasound of the liver after recent contrast-enhanced computed tomography

PURPOSE

The aim of this study is to assess the added diagnostic value of Doppler ultrasound of the liver (DUL) performed within 3 days of contrast-enhanced CT (CECT) for the diagnosis of portal vein (PV) or hepatic vein (HV) thrombosis.

METHODS

Adult patients were included if they underwent DUL within three days after a CECT of the abdomen in the emergency or inpatient setting. Retrospective review of clinical data and imaging reports was performed. In patients with discrepant or positive findings on CECT and/or DUL with respect to PV or HV thrombosis, image review was performed by three fellowship-trained abdominal radiologists in consensus.

RESULTS

The final cohort consisted of 468 patients. Of these, 26 (5.6%) patients had equivocal findings for thrombosis on CECT, and DUL could make a confident diagnosis of positive or negative in 18 (69%) patients. Additionally, there were 2 (0.4%) patients with PV or HV thrombosis on DUL following a limited CECT, and 2 (0.4%) patients who developed interval PV thrombosis between CECT and DUL.

CONCLUSION

DUL after CECT added diagnostic value for PV and/or HV thrombosis in less than 5% of patients. The patency of PV and HV is often not explicitly mentioned in CECT reports at our institution, which may lead to uncertainty for the referring provider as to whether the PV and HV were adequately evaluated. Few CECT have false positive or missed or underreported findings, and a careful review of the original CECT should be performed if DUL is requested.

Imaging findings of en bloc simultaneous liver-kidney transplantation

Simultaneous liver-kidney transplantations (SLKTs) are increasing in incidence, and the en bloc surgical approach is associated with a unique spectrum of vascular complications. En bloc SLKTs have a common arterial supply from the celiac axis and post-operative assessment with Doppler ultrasound can help to localize vascular lesions as either proximal in the shared arterial supply or distal in the organ-specific arteries. Venous complications predominantly include thrombosis or stenosis of the portal vein, hepatic veins, renal vein, or IVC, but have a much lower incidence. Radiologists familiar with the post-operative anatomy and complications can provide meaningful and accurate assessment to help direct clinical care. The purpose of this article is to provide a targeted review of SLKT, review the post-surgical anatomy associated with en bloc SLKT, and review the imaging evaluation of vascular complications associated with SLKT.

Diagnostic accuracy of Doppler ultrasound for detecting hepatic artery stenosis after liver transplantation

AIM

To evaluate the diagnostic accuracy of Doppler ultrasound (DUS) in detecting hepatic artery stenosis (HAS) after liver transplantation using computed tomography angiography (CTA) as the reference standard.

MATERIALS AND METHODS

This study included data from January 2005 to November 2017, where DUS of the hepatic artery of living and deceased donor liver grafts were compared with the reference standard, CTA. DUS parameters, such as intrahepatic artery (IHA) peak systolic velocity (PSV), resistive index (RI), systolic acceleration time (SAT); and extrahepatic artery (EHA) PSV were taken. The optimum cut-off was estimated using area under the receiver operating characteristic curve (AUC). Multivariable logistic regression analysis was developed to predict HAS.

RESULTS

Ninety-nine liver transplant cases were retrieved, 50 met the inclusion criteria where nine patients had significant HAS. HAS patients had a significantly low IHAPSV with a cut-off of 35.1 cm/s (sensitivity 53.8%, specificity 78.4%, AUC 0.701). IHARI had a significantly low RI with a cut-off 0.585 (sensitivity 86.7%, specificity 85.4%, AUC 0.913). The IHASAT cut-off was 0.045 seconds (sensitivity 80%, specificity 91.4%, AUC 0.857). The EHAPSV cut-off was 197.4 cm/s (sensitivity 50%, specificity 99.1%, AUC 0.648). The prediction model using DUS parameters IHARI and IHASAT demonstrated good discrimination with an AUC of 0.930 (95% CI: 0.843, 1.000; sensitivity 93.3%, specificity 88%).

CONCLUSION

A prediction model using the DUS parameters IHARI and IHASAT showed good diagnostic accuracy of 88.6% for monitoring liver transplant patients. If validated externally, this DUS model could be utilised to diagnose HAS in liver transplant recipients.

Ultrasound Findings and Laboratory Predictors of Early Mortality in Patients With Severe Yellow Fever

OBJECTIVE. Yellow fever is a hemorrhagic disease caused by an arbovirus endemic in South America; outbreaks have occurred in recent years. The purpose of this study was to describe abdominal ultrasound findings in patients with severe yellow fever and correlate them with clinical and laboratory data. MATERIALS AND METHODS. A retrospective cohort study was performed between January and April 2018. The subjects were patients admitted to an ICU with polymerase chain reaction-confirmed yellow fever. Bedside sonography was performed within 48 hours of admission. Images were independently analyzed by two board-certified radiologists. Laboratory test samples were collected within 12 hours of image acquisition. Multivariable logistic regression analysis was performed to identify 30-day mortality predictors; p < .05 was considered statistically significant. RESULTS. Forty-six patients (40 [87%] men, six [13%] women; mean age, 47.5 ± 15.2 years) were evaluated with bedside sonography. Laboratory tests showed high serum levels of aspartate aminotransferase (5319 U/L), total bilirubin (6.2 mg/dL), and creati-nine (4.3 mg/dL). Twenty-six (56.5%) patients died within 30 days of admission (median time to death, 5 days [interquartile range, 2-9 days]). The most frequent ultrasound findings were gallbladder wall thickening (80.4%), increased renal cortex echogenicity (71.7%), increased liver parenchyma echogenicity (65.2%), perirenal fluid (52.2%), and ascites (30.4%). Increased renal echogenicity was associated with 30-day mortality (84.6% versus 55.0%; p = .046) and was an independent predictor of this outcome after multivariate analysis (odds ratio, 10.89; p = .048). CONCLUSION. Reproducible abdominal ultrasound findings in patients with severe yellow fever may be associated with severity of disease and prognosis among patients treated in the ICU.

Compatibility and Validation of a Recent Developed Artificial Blood through the Vascular Phantom Using Doppler Ultrasound Color- and Motion-mode Techniques

Background:

Doppler technique is a technology that can raise the predictive, diagnostic, and monitoring abilities in blood flow and suitable for researchers. The application depends on Doppler shift (shift frequencies), wherein the movement of red blood cells away from the probe is determined by the decrease or increase in the ultrasound (US) frequency.

Methods:

In this experiment, the clinical US (Hitachi Avious [HI] model) system was used as a primary instrument for data acquisition and test the compatibility, efficacy, and validation of artificial blood (blood-mimicking fluid [BMF]) by color- and motion-mode. This BMF was prepared for use in the Doppler flow phantom.

Results:

The motion of BMF through the vessel-mimicking material (VMM) was parallel and the flow was laminar and in the straight form (regular flow of BMF inside the VMM). Moreover, the scale of color velocity in the normal range at that flow rate was in the normal range.

Conclusion:

The new BMF that is being valid and effective in utilizing for US in vitro research applications. In addition, the clinical US ([HI] model) system can be used as a suitable instrument for data acquisition and test the compatibility, efficacy, and validation at in vitro applications (BMF, flow phantom components).

Early Effects of Laparoscopic Sleeve Gastrectomy and Laparoscopic One-Anastomosis Gastric Bypass on Portal Venous Flow: a Prospective Cohort Study

BACKGROUND

Portal vein thrombosis (PVT) is an infrequent, yet potentially lethal, complication of bariatric surgery. The aim of this prospective, non-randomized, cohort study is to compare between laparoscopic sleeve gastrectomy (LSG) and laparoscopic one-anastomosis gastric bypass (LOAGB) in terms of their early postoperative effects on portal venous flow and patency.

METHODS

Forty-nine morbidly obese patients were allocated to one of 2 groups (A or B). Group A patients underwent LSG, whereas group B patients underwent LOAGB. Portal venous Doppler ultrasound scanning was performed preoperatively and 2 weeks postoperatively in all cases, in order to assess the portal venous flow (PVF) in terms of flow direction and peak systolic velocity (PSV); as well as to assess the portal venous patency and exclude PVT. The mean change in PSV (ΔPSV) and the mean percentage change in PSV (%ΔPSV) were determined in both groups.

RESULTS

In all cases (group A (n = 26); group B (n = 23)), the direction of PVF was "hepatopetal" both preoperatively and 2 weeks postoperatively. The mean ΔPSV and the mean %ΔPSV were higher in LSG patients "group A" (- 0.84 cm/s and 3.25% respectively) compared with LOAGB patients "group B"(- 0.06 cm/s and 0.27% respectively); P = 0.038 and 0.039 respectively. The mean change in PSV was in the negative direction in both groups, i.e., "deceleration." No cases of PVT were reported in the study.

CONCLUSIONS

Laparoscopic sleeve gastrectomy is associated with greater reduction in portal venous peak systolic flow velocity in the early postoperative period, compared with laparoscopic one-anastomosis gastric bypass.

Liver Congestion Assessed by Hepatic Vein Waveforms in Patients With Heart Failure

Background

It has been reported that the pattern of hepatic vein (HV) waveforms determined by abdominal ultrasonography is useful for the diagnosis of hepatic fibrosis in patients with chronic liver disease. We aim to clarify the clinical implications of HV waveform patterns in patients with heart failure (HF).

Methods

We measured HV waveforms in 350 HF patients, who were then classified into 3 categories based on their waveforms: those with a continuous pattern (C group); those whose V wave ran under the baseline (U group), and those with a reversed V wave (R group). We performed right-heart catheterization, and examined the rate of postdischarge cardiac events, such as cardiac death and rehospitalization due to worsening HF.

Results

The number of patients in each of the 3 HV waveform groups was as follows: C group, n = 158; U group, n = 152, and R group, n = 40. The levels of B-type natriuretic peptide (R vs C and U; 245.8 vs 111.7 and 216.6 pg/mL; P < 0.01) and mean right atrial pressure (10.5 vs 6.7 and 7.2 mm Hg; P < 0.01) were highest in the R group compared with the other groups. The Kaplan-Meier analysis found that cardiac event–free rates were lowest in the R group among all groups (log-rank P < 0.001). In the multivariable Cox proportional hazard analysis, the R group was found to be an independent predictor of cardiac events (hazard ratio, 4.90; 95% confidence interval, 2.23-10.74; P < 0.01).

Conclusion

Among HF patients, those with reversed V waves had higher right atrial pressure and were at higher risk of adverse prognosis.

Functional Hemodynamic Monitoring With a Wireless Ultrasound Patch

In this Emerging Technology Review, a novel, wireless, wearable Doppler ultrasound patch is described as a tool for resuscitation. The device is designed, foremost, as a functional hemodynamic monitor-a simple, fast, and consistent method for measuring hemodynamic change with preload variation. More generally, functional hemodynamic monitoring is a paradigm that helps predict stroke volume response to additional intravenous volume. Because Doppler ultrasound of the left ventricular outflow tract noninvasively measures stroke volume in realtime, it increasingly is deployed for this purpose. Nevertheless, Doppler ultrasound in this manner is cumbersome, especially when repeat assessments are needed. Accordingly, peripheral arteries have been studied and various measures from the common carotid artery Doppler signal act as windows to the left ventricle. Yet, handheld Doppler ultrasound of a peripheral artery is susceptible to human measurement error and statistical limitations from inadequate beat sample size. Therefore, a wearable Doppler ultrasound capable of continuous assessment minimizes measurement inconsistencies and smooths inherent physiologic variation by sampling many more cardiac cycles. Reaffirming clinical studies, the ultrasound patch tracks immediate SV change with excellent accuracy in healthy volunteers when cardiac preload is altered by various maneuvers. The wearable ultrasound also follows jugular venous Doppler, which qualitatively trends right atrial pressure. With further clinical research and the application of artificial intelligence, the monitoring modalities with this new technology are manifold.

Point of Care Ultrasonography for Objective Assessment of Heart Failure: Integration of Cardiac, Vascular, and Extravascular Determinants of Volume Status

BACKGROUND

Lingering congestion portends poor outcomes in patients with heart failure (HF) and is a key target in their management. Studies have shown that physical exam has low yield in this setting and conventional methods for more precise assessment and monitoring of volume status (e.g., body weight, natriuretic peptides, and chest radiography) have significant inherent shortcomings.

SUMMARY

Point of care ultrasonography (POCUS) is a noninvasive versatile bedside diagnostic tool that enhances the sensitivity of conventional physical examination to gauge congestion in these patients. It also aids in monitoring the efficacy of decongestive therapy and bears prognostic significance. In this narrative review, we discuss the role of focused sonographic assessment of the heart, venous system, and extravascular lung water/ascites (i.e., the pump, pipes, and the leaks) in objective assessment of fluid volume status. Key Messages: Since each of the discussed components of POCUS has its limitations, a combinational ultrasound evaluation guided by the main clinical features would be the key to reliable assessment and effective management of congestion in patients with HF.

A large asymptomatic portal vein aneurysm in an old man

Ultrasound (US) is a useful tool in diagnosis and follow-up of portal vein aneurysms (PVA). In the absence of international surgical guidelines on PVAs, US can be effectively used in follow-up of asymptomatic patients not suitable for surgery.