Superb microvascular imaging for the detection of parenchymal perfusion in normal and undescended testes in young children

Superb Microvascular Imaging in Pediatric Focal Nodular Hyperplasia

OBJECTIVE

To investigate superb microvascular imaging (SMI), a novel Doppler ultrasound technique that can visualize low-velocity microvascular flow, for assessing pediatric focal nodular hyperplasia (FNH).

PATIENTS AND METHODS

Nine FNH lesions in 6 patients were enrolled. On SMI and color Doppler imaging (CDI), intralesional vascularity was assessed visually and categorized as typical spoke-wheel pattern (central vessel radiating from the center to the periphery), multifocal spoke-wheel pattern, and nonspecific pattern. We compared the vascular features of the lesions between SMI and CDI and evaluated vascular patterns according to lesion size.

RESULTS

In terms of vascularity pattern, the typical spoke-wheel pattern of FNH was noted more frequently on SMI (67%) than on CDI (11%; P < 0.05). In addition, a multifocal spoke-wheel pattern was noted in all remaining lesions (33%) on SMI. On the contrary, a nonspecific vascular pattern was detected in the majority (78%) of CDI. Regarding the lesion size and vascularity on SMI, the typical spoke-wheel pattern was seen more frequently in the small FNH group than in the large FNH group. The intralesional vascular signal was detected more frequently on SMI (100%) than on CDI (89%).

CONCLUSION

SMI is feasible in evaluating FNH in children and has a greater ability to demonstrate the spoke-wheel pattern than CDI.

Contrast-enhanced ultrasound findings in testicular torsion and non-testicular torsion

PURPOSE

Testicular torsion requires emergency surgery; thus, prompt and correct diagnosis is very important. Ultrasound with color Doppler is usually the first-choice modality for diagnosis; however, skill and experience are required for confident diagnosis. Recently, contrast-enhanced ultrasound for the diagnosis of testicular torsion has been reported, but there have been only a few reports. This study aimed to compare contrast-enhanced ultrasound findings in cases of testicular torsion and non-testicular torsion.

METHODS

Patients who underwent contrast-enhanced ultrasound for acute scrotum at our institution between April 2010 and January 2023 were divided into testicular torsion (n = 17) and non-testicular torsion (n = 16) groups. The respective contrast-enhanced ultrasound findings were retrospectively examined and compared.

RESULTS

In 16 out of 17 cases of testicular torsion, the parenchyma of the affected testis was not enhanced. In the remaining case, reduced contrast enhancement was observed; however, it was still notably less than that observed on the unaffected testis. On the other hand, in all cases of non-testicular torsion (n = 16), the parenchyma of the affected testis was notably enhanced.

CONCLUSION

Contrast-enhanced ultrasound is considered an easy and accurate method for diagnosing testicular torsion.

Comparison of conventional Doppler imaging techniques and superb microvascular imaging in determination of vascularization in undescended testes

Aim

Our aim was to gain an idea about testicular injury by comparing the reduced volume, which is one of the indirect indicators of testicular damage in undescended testes, and by evaluating the reduced microvascular blood flow by superb microvascular imaging, and also to determine whether superb microvascular imaging modes could detect microvascular blood flow in more detail in the decreased volume of undescended testes.

Material and methods

We compared testicular blood flow in undescended testes via conventional Doppler imaging, color superb microvascular imaging, and monochrome superb microvascular imaging techniques with contralateral normally located testis and normal control group. Each sample of testicular tissue was evaluated using a qualitative method. Spot color encoding and linear flow color encoding counts determined in testicular parenchyma were counted separately and expressed as numerical data. The localization of the examined testes in the grayscale was noted (proximal inguinal canal, medial inguinal canal, distal inguinal canal, and scrotal). The volume of undescended testes was calculated automatically via a formula for volume.

Results

Monochrome superb microvascular imaging is significantly superior in visualizing the vascularity of undescended testes compared with color Doppler, power Doppler and color superb microvascular imaging (p = 0.001). Also, undescended testes have a significantly lower blood flow compared with contralateral normal testes (p = 0.001). The volume of undescended testes was significantly lower than the contralateral normal testes.

Conclusions

The volume, structure and blood flow are indirect signs of testicular damage in undescended testes. Monochrome superb microvascular imaging can detect vascularity in undescended testes better than the conventional Doppler imaging technique and color superb microvascular imaging. Based on our findings, we can report that monochrome superb microvascular imaging can be used to evaluate testicular injury and vascularity of undescended testes.

A rare case of bilateral testicular metastasis from ileocecal NET: multiparametric US detection

Testicular metastasis are rare findings and bilateral metastasis of testes are extremely rare. Here we are describing for the first time a case of bilateral testicular metastasis in a patient with a known ileocecal valve NET using an in-depth ultra-sound studying including microvascular flow imaging (MV-flow), ultra-sound new technique, able to detect small vessel slow-signal.

Microvascular Flow Imaging: A State-of-the-Art Review of Clinical Use and Promise

Vascular imaging with color and power Doppler is a useful tool in the assessment of various disease processes. Assessment of blood flow, from infarction and ischemia to hyperemia, in organs, neoplasms, and vessels, is used in nearly every US investigation. Recent developments in this area are sensitive to small-vessel low velocity flow without use of intravenous contrast agents, known as microvascular flow imaging (MVFI). MVFI is more sensitive in detection of small vessels than color, power, and spectral Doppler, reducing the need for follow-up contrast-enhanced US (CEUS), CT, and MRI, except when arterial and venous wash-in and washout characteristics would be helpful in diagnosis. Varying clinical applications of MVFI are reviewed in adult and pediatric populations, including its technical underpinnings. MVFI shows promise in assessment of several conditions including benign and malignant lesions in the liver and kidney, acute pathologic abnormalities in the gallbladder and testes, and superficial lymph nodes. Future potential of MVFI in different conditions (eg, endovascular repair) is discussed. Finally, clinical cases in which MVFI correlated and potentially obviated additional CEUS, CT, or MRI are shown.

Ultrasound manifestations and clinical features of nonpalpable testis in children

To explore the value of ultrasound in the preoperative diagnosis of nonpalpable testis (NPT) in children. A retrospective study of 254 cases with NPT from May 2017 to December 2021. The preoperative ultrasound examination results were compared with the surgical exploration and pathological results. There were 254 cases (312 testes) NPT has got surgery in our centre. The surgical age were from 6 month to 12 years old, the median age was 2.33 years. There were 103 cases (136 testes) diagnosed as intra-abdominal testis (IAT) by preoperative ultrasound, and 80 cases (103 testes) of extra-abdominal testis (EAT), 71 cases (73 testes) of non-viable testis (NVT). There were 102 cases (135 testes) consistented as IAT by the diagnostic laparoscopy, the preoperative ultrasound's coincidence of IAT was 99.02%. There were 80 cases (103 testes) consistented as EAT by the diagnostic laparoscopy, the preoperative ultrasound's coincidence rate was100%. There were 62 cases (62 testes) consistented as NVT by the diagnostic laparoscopy, there were 9 cases (11 testes) misdiagnosed, the preoperative ultrasound's coincidence rate was 84.9%. Ultrasound can provide valuable information for the preoperative diagnosis of children with nonpalpable testicles, and especially good at identifying the EAT and IAT with normal testicular morphology.

The clinical application of ultrasonography with superb microvascular imaging-a review

Superb microvascular imaging (SMI) is among the latest doppler ultrasound methods. It uses an advanced clutter filter to eliminate artifacts caused by breathing, movement and retains the low-speed blood signals in microvessels. The great advantage of SMI is that it can intuitively detect very slow blood signals in microvessels, providing clinicians with more significant information about flow distribution in the target area. Therefore, it is speculated that SMI has important application value. The purpose of this article is to outline the application of SMI in different parts of the body.

An Innovative Ultrasound Technique for Early Detection of Kidney Dysfunction: Superb Microvascular Imaging as a Reference Standard

Background: Superb microvascular imaging (SMI) is an innovative ultrasound image processing technique that provides greater detail and better visualization of small branching vessels. We assume that SMI will provide sufficient information regarding the severity of chronic kidney disease (CKD) and reflecting histological changes. Aims: The aims was to assess the capabilities of SMI imaging regarding the early detection of kidney dysfunction and renal fibrosis in comparison to the reference standard renal biopsy for the early diagnosis of kidney fibrosis. Methods: SMI was performed in patients (n = 52) with CKD stage 2–5, where some of them underwent biopsy proven CKD and fibrosis as part of the diagnosis. In addition, biochemical tests were performed, including kidney function tests, urine collection for proteinuria, and the estimation of GFR by MDRD or CKD-EPI eGFR in CKD patients and healthy controls (n = 17). All subjects underwent SMI, where vascularity is expressed as the SMI index (a low index reflects low vascularity/fibrosis and vice versa). Results: The SMI vascular index was significantly lower in CKD patients as compared with healthy controls (72.2 ± 12.9 vs. 49.9 ± 16.7%, p < 0.01). Notably, a moderate correlation between the SMI index and eGFR was found among the CKD patients (r = 0.56, p < 0.001). Similarly, a strong correlation was found between SCr and the SMI index of the diseased subjects (r = −0.54, p < 0.001). In patients who underwent renal biopsy, the SMI index corresponded with the histological alterations and CKD staging. Conclusions: This study demonstrated that SMI imaging may be utilized in CKD patients of various stages for the evaluation of chronic renal morphological changes and for differentiation between CKD grades.

Added Value of Superb Microvascular Imaging and Virtual Touch Imaging Quantification in Assisting Thyroid Cancer Classification

This prospective study determined the value added by superb microvascular imaging (SMI) and Virtual Touch imaging quantification (VTIQ) to conventional ultrasonography in classifying malignant and benign thyroid nodules. One hundred eighty-three thyroid nodules (TNs) in 120 patients (112 benign and 71 malignant TNs) were evaluated. SMI revealed noticeable variance between benign and malignant TNs (p < 0.001). Malignant nodules tended to have rich vascularity (grade 3: 38/71, 53.5%) compared with benign nodules (grade 3: 33/112, 29.5%). There is a statistically significant difference between malignant and benign TNs with respect to shear-wave speed (SWS) values (all p values <0.001). The SWS mean, maximum and ratio of malignant nodules were 3.97 ± 1.34, 4.79 ± 1.70 and 1.25 ± 0.39, respectively. The SWS mean, maximum and ratio of benign nodules were 2.65 ± 0.42, 2.97 ± 0.46 and 1.15 ± 0.35, respectively. With respect to area under the curve values, the combined use of SMI or VTIQ improved the diagnostic performance of classifying malignant and benign TNs compared with that of ultrasonography alone. The combination of three modalities achieved the greatest area under the curve values (0.9811, 95% confidence interval: 0.95529-1.000), followed by US + VTIQ (0.9747, 0.94543-1.000), US + SMI (0.9032, 0.85345-0.95391) and ultrasonography (0.8291, 0.76417-0.89403).

The Diagnostic Value of Superb Microvascular Imaging in Prediction of Uterine Artery Embolization Treatment Response in Uterine Leiomyomas

OBJECTIVES

We aimed to determine if superb microvascular imaging (SMI) can predict response to uterine artery embolization (UAE) as compared with power Doppler ultrasound.

METHODS

The blood flow and the volume of the dominant leiomyoma was evaluated by power Doppler ultrasonography (PDUS) and SMI 1 day before and 3 months after the UAE procedure. SMI and PDUS blood flow were classified to 4 grades of vascularity. The change in fibroid volume in Grades 0-2 (hypovascular group) was compared to the hypervascular Grade 3 group.

RESULTS

Twenty-eight women (mean age, 40.9 years; range, 33-53 years) were examined with PDUS and SMI before and 3 months after UAE. The volume reduction was statistically significantly higher hypervascular group (P < .05). When we accept 30% or more volume reduction as a good response to UAE, the positive predictive value, negative predictive value, sensitivity, specificity, and accuracy of SMI were 100, 64, 73.6, 100, and 82.1%, respectively. There was excellent agreement between the two blinded observers in SMI measurements.

CONCLUSIONS

SMI, with its high reproducibility, provides further microvessel information than PDUS in uterine fibroids. It may be a useful tool in prediction of response to UAE treatment and improve counseling and patient selection for UAE versus medical or surgical treatment options.

Analysis of vascularization in thyroid gland nodes with superb microvascular imaging (SMI) and CD34 expression histology: a pilot study

Background

The Doppler sonography technique known as "superb microvascular imaging" (SMI) is advancing sonographic micro vascularization imaging in various disciplines. In this study, we aimed to determine whether SMI could reliably reproduce the blood flow in thyroid nodes and whether malignancy could be diagnosed, based on vascularization properties. Immunhistochemical staining by CD34 and SMI where used to determine the vascularization of nodes in terms of quantified vascularization parameters gained by computational evaluation.

Methods

We used image analysis programs to investigate whether the quantitative value for vascularization strength in the thyroid node, measured with SMI, was correlated with the actual degree of vascularization, determined microscopically. We included 16 patients that underwent thyroid resections. We prepared thyroid gland tissue slices for immunohistochemistry and labelled endothelial cells with CD34 to visualize blood vessels microscopically. We used image analysis programs, ImageJ, to quantify SMI Doppler sonographic measurements and CellProfiler to quantify CD34 expression in histological sections. We evaluated the numeric values for diagnostic value in node differentiation. Furthermore, we compared these values to check for correlations.

Results

Among the 16 nodes studied, three harboured malignant tumours (18.75%): two papillary and one follicular carcinoma. Among the 13 benign lesions (81.25%), four harboured follicular adenomas. Malignant and benign nodes were not significantly different in sonographic (0.88 ± 0.89 vs. 1.13 ± 0.19; p = 0.2790) or immunohistochemical measurements of vascularization strength (0.05 ± 0.05 vs. 0.08 ± 0.06; p = 0.2260).

Conclusion

We found a positive, significant correlation (r = 0.55588; p = 0.0254) between SMI (quantitative values for vascularization strength) and immunohistochemistry (CD34 staining) evaluations of thyroid nodes.

Microvascular imaging ultrasound (MicroV) and power Doppler vascularization analysis in a pediatric population with early scrotal pain onset

INTRODUCTION

The power Doppler is a useful tool in the evaluation of pediatric acute scrotal pain. Nonetheless, it may have some inherent limitations in scrotal vascularization analysis, potentially causing unnecessary surgery. The microvascular imaging ultrasound (MicroV) is an innovative Doppler technique able to improve the detection of very low flow. This retrospective study aims to compare both power Doppler and MicroV in the evaluation of a pediatric population with early-stage scrotal pain onset, first in testis vascularization analysis, and second in their diagnostic performances.

MATERIALS AND METHODS

69 patients met the following inclusion criteria, age < 18-year-old, a clinical diagnosis of acute scrotal disease, pain onset ≤ 6 h, ultrasound examination (including B-mode, power Doppler, and MicroV), 3-months follow-up. For both power Doppler and MicroV, through a defined vascularization scale, it was evaluated the agreement in vascularization detection, and the sensitivity and specificity in US diagnostic abilities.

RESULTS

Retrospective diagnoses were of 8 testicular torsion, 15 orchi-epididymitis, and 46 children with other scrotal conditions. Power Doppler provided inconclusive US evaluation in 37.68% of the cases, while MicroV only in the 1.45% (p < 0.0001). Testicular torsion and orchi-epididymitis were identified, respectively, with MicroV in 100% (sensitivity, specificity, PPV, NPV, and accuracy of 100%) and 80% of patients (80% sensitivity, 100% specificity and PPV, 94.73% NPV, 95.65% accuracy); with power Doppler the identification was, respectively, of 87.5% (87.5% sensitivity, 100% specificity and PPV, 98.38% NPV and accuracy) and of 73.3% (73.33% sensitivity, 98.14% specificity, 91.66% PPV, 92.98% NPV, 92.75% accuracy).

CONCLUSIONS

Our findings indicate that MicroV is a reliable technique in vascularization detection of pediatric testes, being able also to detect vascularization in healthy testicles with no-flow at power Doppler examination. Moreover, MicroV could be a valuable ally in the US diagnostic of children with early-stage scrotal pain onset.

Application of Superb Microvascular Imaging in the Diagnosis of Vascular Erectile Dysfunction

To compare the difference between superb microvascular imaging (SMI) and color doppler flow imaging (CDFI) on vascular grading and blood flow display rate of the penile cavernous artery of vascular erectile dysfunction (ED), and to evaluate the length of time to obtain blood flow spectrum. 68 patients with ED were preformed for the examination of SMI and CDFI. The difference between the two techniques on vascular grading and blood flow display rate were compared. Hemodynamic parameters, namely peak systolic velocity (PSV), end diastolic velocity (EDV), and resistant index (RI) and the length of time obtained blood flow spectrum were compared. SMI was more sensitive to assess vascular grading and blood flow display rate than CDFI (P < 0.05). Hemodynamic parameters (PSV, EDV, and RI) measured by SMI and CDFI were well correlated (r = 0.981, P < 0.001; r = 0.879, P < 0.001; r = 0.937, P < 0.001). The duration of time necessary obtained the spectrums of grade 3 and grade 4 blood flow was shorter than that of grade 1 and grade 2, and SMI was comparatively shorter than CDFI (P < 0.05). In conclusion, SMI detected the blood flow of the penile cavernous artery better and maked the examination time shorter than CDFI, which can be considered as a more effective technique to diagnose vascular ED.

Use of contrast enhanced ultrasound in testicular diseases: A comprehensive review

Background

Contrast‐enhanced ultrasound (CEUS) is a sonographic technique that increases the diagnostic accuracy of ultrasound and color Doppler ultrasound (CDUS) when studying testicular abnormalities. However, its role in clinical practice is still debatable because there are no accepted standards regarding how and when this technique should be used for patients with testicular disease.

Objectives

To perform a nonsystematic review of the current literature to highlight the strength and flaws of performing CEUS and to provide a critical overview of current research evidence on this topic.

Materials and methods

A thorough search of published peer‐reviewed studies in PubMed was performed using proper keywords.

Results

Strong enhancement of neoplastic lesions (both benign and malignant) during CEUS aids in differential diagnosis with non‐neoplastic lesions, which usually appears either nonenhanced or enhanced in a manner similar to that of the surrounding parenchyma. CEUS enhancement has a high predictive value in the identification of neoplastic lesions, whereas a similar or complete absence of enhancement may be interpreted as strong evidence of benignity, although there are exceptions. Literature on quantitative analysis is still scarce, though promising, particularly in distinguishing benign from malignant neoplasms. Furthermore, CEUS may be useful in many emergency situations, such as acute scrotum, blunt scrotal trauma, and focal infarction of the testis. Finally, CEUS can help increase the probability of sperm recovery in azoospermic males.

Discussion and conclusion

CEUS is a safe, easy‐to‐perform, and cost‐effective diagnostic tool that can provide a more accurate diagnosis in testicular lesions and acute scrotal disease. However, further studies with larger cohorts are required to refine the differential diagnosis between benign and malignant neoplasms. Finally, these preliminary results can instigate the development of innovative research on pre‐testicular sperm extraction to increase the chances of sperm recovery.

Clinical Applications of Superb Microvascular Imaging in the Superficial Tissues and Organs: A Systematic Review

Superb microvascular imaging (SMI) is an innovative Doppler technique for vascular examination. It uses an intelligent algorithm that efficiently separates low-speed flow signals from motion artifacts so that it can assess microvessels and the vessel distribution in detail. This article reviews the clinical applications of SMI in the disorders of superficial tissues and organs including thyroid nodules, breast tumors and lymph node diseases etc. More information of diseases that are closely associated with angiogenesis can be shown by SMI than other noninvasive examinations. Although some limitations exist, this safe and convenient technique is becoming acceptable and would play a more important role in disease diagnosis and therapeutic responses evaluation.

Cerebral superb microvascular imaging in preterm neonates: in vivo evaluation of thalamic, striatal, and extrastriatal angioarchitecture

PURPOSE

To explore the potential of superb microvascular imaging (SMI) in visualizing brain microvessels in preterm neonates of different gestational ages (GA).

METHODS

In this retrospective, observational pilot study, 15 preterm newborns were equally divided into GA groups: extremely (GA < 28 weeks), very (28-31 weeks), and moderate to late (32-37 weeks) preterm. All patients underwent conventional transcranial ultrasounds during the first day of life following the American Institute of Ultrasound in Medicine practice guidelines. SMI was then performed; based on their SMI morphology and location, brain microvessels were classified as extrastriatal (cortical and medullary), striatal, or thalamic. Two examiners independently classified vessels as visible or invisible. To assess the association between vessel visibility and GA, binomial logistic regression analysis (separate for each microvessel group) was performed, taking visibility as a dependent variable and both examiners and GA as predictor variables.

RESULTS

A statistically significant difference among GA groups was found in sex (P = 0.030), birth weight (P = 0.007), and Apgar score within 1 min after birth (P = 0.024). Microvascular visibility increased with GA for superficial vessels (P < 0.05 for both cortical and medullary), while striatal and thalamic vessels were visible in all neonates irrespective of their GA.

CONCLUSIONS

SMI technology shows promise to assess brain microvasculature in preterm neonates, even potentially providing data on early brain development.

Narrative review of multiparametric ultrasound in parotid gland evaluation

Disorders affecting parotid gland represent a heterogeneous group comprising congenital, inflammatory and neoplastic diseases which show a focal or diffuse pattern of appearance. The differentiation of neoplastic from non-neoplastic conditions of parotid glands is pivotal for the diagnostic imaging. Frequently there is evidence of overlapping between the clinical and the imaging appearance of the various pathologies. The parotid gland is also often object of study with the combination of different techniques [ultrasound-computed tomography-magnetic resonance imaging (US-CT-MRI), ex.]. Compared to other dominant methods of medical imaging, US has several advantages providing images in real-time at lower cost, and without harmful use of ionizing radiation and of contrast enhancement. B-mode US, and the microvascular pattern color Doppler are usually used as first step evaluation of parotid lesions. Elastography and contrast-enhanced US (CEUS) has opened further possible perspectives to improve the differentiation between benign and malignant parotid lesions. The characterization of the parotid tumors plays a crucial role for their treatment planning and for the prediction of possible surgical complications. We present, here an updated review of the most recurrent pathologies of parotid gland focusing on the diagnostic power of multiparametric US including CEUS and ultrasound elastography (USE); limitations, advantages and the main key-points will be presented.

Comparison of Superb Microvascular Imaging With Other Doppler Methods in Assessment of Testicular Vascularity in Cryptorchidism

Superb microvascular imaging (SMI) is a new Doppler technique. Superb microvascular imaging can observe microvascular and low-velocity blood flow. Superb microvascular imaging is available in 2 modes: color SMI (cSMI) and monochrome SMI (mSMI). To evaluate testicular flow, we have compared color Doppler ultrasound (CDUS), power Doppler ultrasound (PDUS), Advanced Dynamic Flow (ADF), cSMI, and mSMI techniques.Fifty-six participants less than 36 months of age were included in the study (mean age, 18.21 ± 1.5 months). One of the testes examined was in the scrotal sac, and the other was undescended testis (UT), and its location was at the level of the lower/middle inguinal canal. Testicular vascularization was evaluated with the CDUS, PDUS, ADF, and SMI techniques. Spot and linear signal encoding detected in the parenchyma were recorded between 0 and III for each technique. At the level of the testicle hilus, the outer boundary of the testicle was drawn manually along the long axis of each testis, and the vascularity index (VI) was automatically calculated from this area on the cSMI method.There was no significant relationship between normal and undescended testicles in terms of age, weight, height, testicle volume, and VI. Superb microvascular imaging was found to be superior in showing testicular vascularity, especially UT. The power of detecting Doppler signal in mSMI is significantly higher than in other methods (P < 0.001). The most valuable method according to the power of detecting testicular vascularity was mSMI. Next were cSMI, ADF, PDUS, and CDUS.In conclusion, the SMI technique should be included in vascular examination in pediatric patients with UT. The SMI technique can play an important role in assessing vascularization of UT.

Ultrasonographic Demonstration of the Tissue Microvasculature in Children: Microvascular Ultrasonography Versus Conventional Color Doppler Ultrasonography

Microvascular ultrasonographic imaging is the most recent and unique Doppler ultrasound technique. It uses an advanced clutter filter that can remove clutter artifacts and preserve the low-velocity microvascular flow signal. The potential advantages of microvascular ultrasonography are its superiority in detection and visualization of the small blood vessels in tissues, providing radiologists with more information on the vascular structures. Therefore, it has shown particular value in the clinical fields. The aim of this study was to provide microvascular ultrasonographic images for the tissue microvasculature, including the brain, thyroid gland, kidney, urinary bladder, small bowel, ovary, testis, lymph node, and hemangiomas in children, focusing on the comparison with conventional color Doppler ultrasonographic images.

Quantitative Imaging in Pediatric Hepatobiliary Disease

Pediatric hepatobiliary imaging is important for evaluation of not only congenital or structural disease but also metabolic or diffuse parenchymal disease and tumors. A variety of ultrasonography and magnetic resonance imaging (MRI) techniques can be used for these assessments. In ultrasonography, conventional ultrasound imaging as well as vascular imaging, elastography, and contrast-enhanced ultrasonography can be used, while in MRI, fat quantification, T2/T2^* mapping, diffusion-weighted imaging, magnetic resonance elastography, and dynamic contrast-enhanced MRI can be performed. These techniques may be helpful for evaluation of biliary atresia, hepatic fibrosis, nonalcoholic fatty liver disease, sinusoidal obstruction syndrome, and hepatic masses in children. In this review, we discuss each tool in the context of management of hepatobiliary disease in children, and cover various imaging techniques in the context of the relevant physics and their clinical applications for patient care.

Microvascular Flow Imaging of Residual or Recurrent Hepatocellular Carcinoma after Transarterial Chemoembolization: Comparison with Color/Power Doppler Imaging

Objective

To determine the feasibility of microvascular flow imaging (MVFI) in comparison with color/power Doppler imaging (CDI/PDI) for detection of intratumoral vascularity in suspected post-transarterial chemoembolization (TACE) residual or recurrent hepatocellular carcinomas (HCCs) by using contrast-enhanced ultrasonography (CEUS) or hepatic angiography (HA) findings as the reference standard.

Materials and Methods

One hundred HCCs (mean size, 2.2 cm) in 100 patients treated with TACE were included in this prospective study. CDI, PDI, and MVFI were performed in tandem for evaluating intratumoral vascularity of the lesions by using an RS85 ultrasound scanner (Samsung Medison Co., Ltd.). Intratumoral vascularity in each technique was assessed by two radiologists in consensus by using a 5-point scale. Then, one of the two radiologists and another radiologist performed additional image review in the reverse order (MVFI-PDI-CDI) for evaluation of intra- and interobserver agreements. Results were then compared with those of either HA or CEUS as the reference. The McNemar test, logistic regression analysis, and intraclass correlation coefficient (ICC) were used.

Results

CEUS or HA revealed intratumoral vascularity in 87% (87/100) of the tumors. Sensitivity (79.3%, 69/87) and accuracy (80.0%, 80/100) of MVFI were significantly higher than those of CDI (sensitivity, 27.6% [24/87]; accuracy, 37.0% [37/100]) or PDI (sensitivity, 36.8% [32/87]; accuracy, 44.0% [44/100]) (all p < 0.05). CDI, PDI, and MVFI presented excellent intraobserver (ICCs > 0.9) and good interobserver agreements (ICCs > 0.6).

Conclusion

MVFI demonstrated significantly higher sensitivity and accuracy than did CDI and PDI for the detection of intratumoral vascularity in suspected residual or recurrent HCCs after TACE.

Acute scrotal pain in pediatric patients: diagnosis with an innovative Doppler technique (MicroV)

Acute scrotal pain is one of the most frequent symptoms in pediatric patients visited in the Emergency Department. Ultrasonography with color and power Doppler represents the first-line method that clinicians use to carry out the differential diagnosis between spermatic cord torsion and inflammation, but sensitivity and specificity are 63-100% and 97-100%, respectively; this variability may be related to operator's experience and testis vascular hemodynamics and also to machine performance and patient age. Recent technological innovations have made possible to create a new Doppler mode called ultrasound microvascular imaging. This technique exploits algorithms capable of separating low frequencies of static tissue artifacts from ones of very weak flows. It is known as MicroV (from Esaote) and Superb microvascular imaging (from Toshiba). It provides both macrocirculation vascular maps, as a typical Doppler feature, and microcirculation vascular maps. Furthermore, the use of background subtraction could improve the visibility of small vascular structures. We report a case of a pediatric patient suffering from acute scrotal pain assessed ultrasonographically with this innovative Doppler technique (MicroV) that may give more confidence in detecting testicular vascular signals if compared with traditional Doppler techniques.

Ultrasound Microflow Imaging Technology for Diagnosis of Adhesive Capsulitis of the Shoulder

OBJECTIVES

To assess the diagnostic accuracy of Superb Microvascular Imaging (SMI; Canon Medical Systems, Otawara, Japan) at the subcoracoid triangle for adhesive capsulitis of the shoulder, to compare the diagnostic value of SMI with that of conventional ultrasound (US) and power Doppler ultrasound (PDUS) findings, and to investigate the correlation between vascular flow on SMI with clinical features.

METHODS

Our study included 39 patients with a diagnosis of adhesive capsulitis and 35 healthy patients as a control group. The echogenicity in the rotator interval and coracohumeral ligament thickness were assessed with conventional US. Vascular flow in the subcoracoid fat triangle was evaluated with SMI and PDUS (SMI and PDUS areas). A receiver operating characteristic curve analysis was performed to evaluate diagnostic accuracy. The correlation between US findings and the range of motion, pain intensity, and duration of symptoms was also evaluated.

RESULTS

The SMI area was higher in the adhesive capsulitis group than in the control group (2.95 versus 0 mm² ; P < .01). The visualization of vascular flow at the subcoracoid fat triangle was superior with SMI compared with PDUS (P < .01). In the receiver operating characteristic analysis, the SMI area showed higher diagnostic performance, with an area under the curve of 0.90 compared with other US findings. The area of SMI vascular flow was also negatively correlated with external rotation and forward flexion (P < .05) in the adhesive capsulitis group.

CONCLUSIONS

Measurement of vascular flow at the subcoracoid fat triangle using SMI facilitated the diagnosis of adhesive capsulitis. Superb Microvascular Imaging was superior to PDUS in diagnostic performance. Vascular flow was negatively correlated with the range of motion of external rotation and forward flexion.

Ultrasonographic superb microvascular imaging for emergency surgery of intracerebral hemorrhage

Ultrasonography (US) has been used as a reliable imaging modality, providing real-time information during neurosurgical operations. One recent innovative US technique, superb microvascular imaging (SMI), visualizes small vessels and flow, which are not detected with standard US with doppler. We apply SMI to intraoperative US monitoring in emergency surgery for intracerebral hemorrhage (ICH). Eleven consecutive patients with ICH underwent endoscopic emergency surgery under US monitoring with SMI. After performing a small craniotomy, US images were obtained using SMI, a fusion technique, and a contrast agent technique, with the probe on the brain surface during surgery. Fusion images were obtained with the probe on the head before craniotomy in some patients. Animated US images with SMI could differentiate hematoma containing no vessels from brain tissue, and flow images using SMI and contrast agent techniques clarified the borderlines. Animated fusion images of intraoperative US and preoperative CT provided information on the extent of hematoma and residual hematoma during emergency surgery. We made various fusion CT images showing intracranial hematoma with US probes and decided on the skin incision line before beginning surgery, as if we were using a neuronavigation system. US with SMI, contrast agent, and fusion techniques provide information on the extent of intracranial hematoma and residual hematoma with no vessels and no flow. Monitoring by US and fusion CT images is useful for ICH surgery as a next-generation neuronavigator.

Scrotal Ultrasound Is Not Routinely Indicated in the Management of Cryptorchidism, Retractile Testes, and Hydrocele in Children

Cryptorchidism, or undescended testes, is the most common congenital genitourinary anomaly. A failure or delay of treatment may result in reduced fertility or an increased risk of testicular cancer. The American Urological Association (AUA) recommends that a scrotal ultrasound (SUS) not be performed in the preoperative management of cryptorchidism. This study investigated how likely pediatricians were to perform SUS despite the AUA guidelines. We retrospectively studied 243 patients referred to a single pediatric urology practice for clinically diagnosed testis pathology including undescended testis, hydrocele, and retractile testis over a 4-year period (January 1, 2015, to December 30, 2018). A total of 72 patients (29.6%) underwent a SUS ordered by their pediatrician prior to the pediatric urology visit. Pediatricians should be aware that SUS performed prior to pediatric urological evaluation does not alter management and is associated with a significant financial cost in patients with cryptorchidism or hydrocele.

Evaluation of Ovarian Vascularity in Children by Using the "Superb Microvascular Imaging" Ultrasound Technique in Comparison With Conventional Doppler Ultrasound Techniques

OBJECTIVES

The aim of this study was to assess the feasibility of the novel "superb microvascular imaging" (SMI) Doppler ultrasound technique to detect ovarian vascularity in healthy children and to compare it with the conventional Doppler ultrasound techniques.

METHODS

This prospective study included 140 girls, aged 3 to 18 years, for which an abdominal ultrasound study was requested in the pediatrics outpatient clinics for suspicion of nonovarian pathologies. Nineteen individuals were excluded from the study due to incomplete ultrasound scanning. For the remaining 121 cases, gray scale ultrasound evaluation was performed followed by color Doppler imaging, power Doppler imaging, advanced dynamic flow, color SMI, and monochrome SMI to detect the presence and degree of vascularity in the ovaries. Ultrasound scanning was performed for all participants by the same doctor by using curvilinear probe via the suprapubic approach, and the images were independently evaluated by 3 different observers. The images were assessed with regard to the degree of vascularity and the presence of artifacts.

RESULTS

A total of 146 ovaries (42 right, 54 left, and 25 bilateral) were examined by sonography. The mean interrater agreement regarding the detection of vascularity was moderate for the color Doppler imaging, power Doppler imaging, advanced dynamic flow, and monochrome SMI techniques (κ = 0.514-0.551) and substantial for the color SMI technique (κ = 0.636) (P < .001). The techniques were found to be statistically significant for detecting vascularity: monochrome SMI > color SMI > power Doppler imaging > color Doppler imaging > advanced dynamic flow (P < .001).

CONCLUSION

SMI is a promising tool that can detect ovarian vascularity more effectively than the conventional Doppler ultrasound techniques.

Characterization of Placental Microvasculature Using Superb Microvascular Imaging

Superb Microvascular Imaging (SMI; Canon Medical Systems, Tustin, CA) uses clutter suppression to extract flow signals at rapid frame rates, which provides high-resolution vessel-branching details without the need for contrast agents. The potential diagnostic benefits of SMI, as described in other areas of medicine, requires further exploration during pregnancy. In this pictorial essay, we demonstrate the complementary use of SMI compared to conventional Doppler ultrasound and how it may improve our ability to characterize placental microvascular patterns without the need for ultrasound contrast agents.

Seeing the Unseen: Evaluating Testicular Vascularity in Neonates by Using the Superb Microvascular Imaging Ultrasound Technique

OBJECTIVES

To evaluate testicular vascularity in neonates by using the novel Superb Microvascular Imaging (SMI; Toshiba Medical Systems Corporation, Tokyo, Japan) ultrasound (US) technique and to compare this technique to conventional Doppler US techniques.

METHODS

A total of 140 healthy neonates between 2 and 60 days old who were admitted for routine screening were included in the study. However, in 9 cases, the Doppler study could not be completed. In the remaining 131 cases, color Doppler imaging (CDI), power Doppler imaging (PDI), Advanced Dynamic Flow (ADF; Toshiba Medical Systems), and monochrome SMI (mSMI) techniques were performed on a single representative testicle. Real-time cine images were captured for 5 to 10 seconds for each technique by using a high-frequency (7.2-14-MHz) linear transducer. The images were evaluated by 3 observers using a grading system to quantify the degree of vascularity and artifact interference.

RESULTS

A total of 131 testicles (74 right and 57 left) were evaluated, and vascularity was shown in 110 (84%) testicles with CDI, 109 (83%) with PDI, 94 (72%) with ADF, and 128 (98%) with mSMI by the consensus of all observers. The Doppler techniques were ranked from highest to lowest in the following order based on the degree of vascularity detected: mSMI > PDI > CDI > ADF (P < .001). Based on the presence of artifacts, the Doppler techniques were ranked as follows from high to low: ADF > CDI > PDI > mSMI (P < .001).

CONCLUSIONS

Superb Microvascular Imaging is a promising US technique that appears to detect testis vascularity better than conventional Doppler US techniques; however, further research is needed to support the results of this study.

Visibility of the graft hepatic artery using superb microvascular imaging in liver transplantation recipients: initial experience

Background Hepatic artery (HA) obstruction is one of the most threatening complications following liver transplantation (LT); however, conventional color Doppler imaging (CDI) suffers from technical limitations regarding the visualization of fine vessels and low-velocity blood flow. Purpose To test the visibility of HA in postoperative evaluation of LT using a superb microvascular imaging (SMI). Material and Methods This retrospective study was approved by our institutional review board. Fifty-five consecutive patients (58 grafts; mean age = 56 years) who underwent LT with Doppler ultrasonography (US) on postoperative day 1 were included. We compared the subjective visibility of HA and objective measurements of HA caliber, visible HA length on CDI, monochrome SMI (mSMI), contrast-enhanced mSMI (CE-mSMI), and contrast harmonic imaging (CHI). Reproducibility of HA caliber measurements on SMI techniques were also evaluated by using intraclass correlation coefficients (ICCs). Results The subjective image quality for visibility of HA tended to be graded higher with mSMI than CDI, and with CE-mSMI than mSMI ( P < 0.001). The overall reproducibility of HA caliber measurements was good to excellent for both mSMI and CE-mSMI (ICC = 0.674-0.855). HA caliber measurements on mSMI and CE-mSMI strongly correlated with CHI ( R = 0.785, 0.798, P < 0.001), while mean HA length on mSMI was significantly longer than on CDI (1.88 ± 0.83 vs. 1.42 ± 1.01cm, P = 0.004), and even longer on CE-mSMI (vs. 3.28 ± 1.11 cm, P < 0.001). Conclusion The mSMI technique shows good reproducibility and correlates well with currently used methods for postoperative evaluation of HA in LT recipients. It is further improved by administration of an US contrast agent.

Microvessel ultrasound of neonatal brain parenchyma: feasibility, reproducibility, and normal imaging features by superb microvascular imaging (SMI)

Objectives

To evaluate the feasibility and reproducibility of superb microvascular imaging (SMI) of the neonatal brain and to describe normal imaging features.

Methods

We performed transcranial ultrasound with SMI in 19 healthy term-born neonates. SMI was done according to a structured examination protocol, using two linear 18 MHz and 14 MHz transducers. Superficial and deep scans were acquired in the coronal and sagittal planes, using the left and right superior frontal gyri as anatomical landmarks. All SMI views were imaged by monochrome and colour SMI and evaluated with respect to visibility of extrastriatal (i.e. cortical and medullary) and striatal microvessels.

Results

We have described normal morphologic features of intraparenchymal brain microvasculature as “short parallel” cortical vessels, “smoothly curved” medullary vessels, and deep striatal vessels. In general, SMI performance was better on coronal views than on sagittal views. On superficial coronal scans, cortical microvessels were identifiable in 90–100%, medullary microvessels in 95–100%. On deep scans, cortical and medullary microvessels were visible in all cases, while striatal microvessels were identifiable in 71% of cases.

Conclusions

Cerebral SMI ultrasound is feasible and well-reproducible and provides a novel non-invasive imaging tool for the assessment of intraparenchymal brain microvasculature (extrastriatal and striatal microvessels) in neonates without the use of contrast.

Key Points

• Superb microvascular imaging (SMI) of the neonatal brain is feasible and reproducible.

• SMI depicts extrastriatal and striatal microvessels.

• SMI detects two types of extrastriatal microvessels: cortical and medullary.

Electronic supplementary material

The online version of this article (10.1007/s00330-018-5743-1) contains supplementary material, which is available to authorized users.

Efficacy of Superb Microvascular Imaging for Diagnosing Acute Cholecystitis: Comparison with Conventional Ultrasonography

We evaluated the diagnostic performance of ultrasonography (US) plus superb microvascular imaging (SMI) compared with conventional US alone for diagnosing acute cholecystitis. We included 54 patients with suspected biliary disease. The SMI pixel count showing flow signal was measured in the region of interest of the gallbladder bed of the liver. Two radiologists independently evaluated imaging features and rated five-point diagnostic likelihood level before versus after the additional SMI using the cutoff SMI pixel count. The SMI pixel count was significantly higher in acute than in non-acute cholecystitis (169.84 vs. 27.48, p < 0.001). The optimal SMI cutoff pixel count for predicting acute cholecystitis obtained by receiver operating characteristic curve was 56.67(82.8% sensitivity, 92.0% specificity). The area under the curve value was significantly higher after the additional SMI than before (0.798-0.863 vs. 0.701-0.736, p < 0.05). US plus SMI could objectively improve diagnostic performance compared with conventional US for acute cholecystitis.

Diagnostic performances of superb microvascular imaging, shear wave elastography and shape index in pediatric lymph nodes categorization: a comparative study

OBJECTIVE

To determine the diagnostic utility of a vascularity index via superb microvascular imaging in lymph nodes of children with malignant lymphoma and acute lymphadenitis compared to normal lymph nodes.

METHODS

We performed a retrospective study for multiparametric lymph node (LN) evaluation. Malignant lymphoma diagnosed via histopathological examination and lymph nodes receiving an acute lymphadenitis diagnosis based on clinical and laboratory findings constituted the study subgroups. We calculated a shape index [SI (percent of shortest to longest diameter)] using grayscale ultrasonography and elasticity and velocity values via shear wave elastography (SWE) as well as a vascularity index (VI) using superb microvascular imaging (SMI) for comparison with normal lymph nodes.

RESULTS

45 lymph nodes diagnosed with malignant lymphoma, 72 lymph nodes diagnosed with acute lymphadenitis and 146 normal lymph nodes were evaluated. For differentiating lymphoma from normal lymph nodes, vascularity index cut-off values higher than 15% represented a diagnostic accuracy of 95%; cut-off elasticity values higher than 17 kPa exhibited a diagnostic accuracy of 99%. Optimal VI, elasticity, velocity and SI cut-off values in differentiating lymphoma from lymphadenitis were 15%, 17 kPa, 2.45 m sn^-1 (p < 0.001) and 65% (p < 0.002) with calculated diagnostic accuracies of 83, 87, 88 and 68%, respectively.

CONCLUSION

Vascularity index values obtained via superb microvascular imaging and SWE would be reasonably useful in differentiating malignant lymphoma and acute lymphadenitis from normal LNs. SWE would be more efficient in distinguishing malignant lymph nodes from acute lymphadenitis compared with superb microvascular imaging. Advances in knowledge: Vascularity index by superb microvascular imaging would be a novel Doppler parameter in differentiating both lymphoma from lymphadenitis and also lymphadenitis from normal lymph nodes.

Evaluation of parotid glands in healthy children and adolescents using shear wave elastography and superb microvascular imaging

OBJECTIVES

We aim to determine parotid gland elasticity values from healthy children and adolescents using shear wave elastography (SWE). We also define the degree of vascularity using superb microvascular imaging (SMI), power Doppler (PD), and color Doppler (CD) and compare SMI with CD and PD.

MATERIALS AND METHODS

A total of 100 cases, comprising 50 girls and 50 boys, with ages ranging from 3 to 17 years were included in this prospective study. SWE, SMI, PD, and CD measurements were taken from both parotid glands, and the relationships with sex, age, and body mass index (BMI) were determined. The SMI was compared with the PD and CD.

RESULTS

The median elasticity values measured with SWE were 8.37 ± 2.09 kPa and 1.68 ± 0.26 m/s on the right and 8.33 ± 2.04 kPa and 1.69 ± 0.26 m/s on the left. There were significant positive correlations present for those aged below and above 10 years and for BMI with elasticity values. The median vascular spot numbers measured using SMI, PD, and CD were 5 ± 1.70, 3.5 ± 1.45, and 2 ± 1.1 on the right and 4 ± 1.7, 4 ± 1.43, and 2 ± 1.05 on the left, respectively. The median values obtained with SMI were significantly higher than the median values obtained with both PD and CD.

CONCLUSION

This study determined the reference SWE, SMI, PD, and CD values for normal parotid glands in healthy children and adolescents. Elasticity values were affected by age and BMI. There was no correlation between vascularity values and age, sex, or BMI. SMI provided more detailed information about vascularity compared with the other methods.

Testicular ultrasensitive Doppler preliminary experience: a feasibility study

Background Ultrasensitive Doppler is a novel non-invasive ultrasound (US) Doppler technique that improves sensitivity and resolution for the detection of slow flow. Purpose To investigate the feasibility of ultrasensitive Doppler (USD) for testicular disease diagnosis, using both qualitative and quantitative results. Material and Methods This prospective study was conducted in 160 successive men referred for scrotal US including B-mode and conventional Color-Doppler. A new USD sequence and algorithm dedicated to academic research were implemented into the US system. The quality criterion for a successful examination was the detection of well delineated intratesticular vessels. Qualitative USD results were described in terms of tumor vascular architecture and flow intensity for different pathologies for 41 patients. The testicular vascularization (TV), defined as a vessel's surface ratio, was quantified using customized MATLAB® software and compared in azoospermic and normal patients. Results USD was acquired successfully in 153/160 patients (95.6%). The tumor vascular architecture differed depending on the nature of the tumors. Leydig cell tumors exhibited mostly circumferential vascularization, while germ cell tumors exhibited straight vessels through the tumors, or anarchic vascular maps. USD improved the diagnostic performance of testicular Doppler US in a case of incomplete spermatic cord torsion and acute epididymitis. The reproducibility of TV measurements established an interclass correlation of 0.801. Non-Klinefelter syndrome non-obstructive azoospermia patients exhibited a lower TV compared to normal patients, to Klinefelter syndrome, and to obstructive azoospermia patients ( P < 0.002, P < 0.005, and P < 0.05, respectively). Conclusion Testicular USD can become a promising technique for improving US diagnosis of tumors, acute scrotum, and for determining infertility status.

Diagnostic Performance of Superb Microvascular Imaging and Other Sonographic Modalities in the Assessment of Lateral Epicondylosis

OBJECTIVES

The aim of this study was to compare the diagnostic performance of different sonographic modalities for diagnosing lateral epicondylosis.

METHODS

A total of 50 symptomatic and 50 asymptomatic common extensor tendons in 44 patients with lateral epicondylosis, and 25 healthy participants were prospectively examined by B-mode sonography, color Doppler imaging, power Doppler imaging, Superb Microvascular Imaging (SMI; Toshiba Medical Systems Corporation, Tokyo, Japan), and strain elastography. We evaluated blood flow in common extensor tendons by using a grading system with color Doppler imaging, power Doppler imaging, and SMI. The diagnostic performance of the modalities was compared.

RESULTS

When a cutoff value of hypoechogenicity was used for the mean strain ratio, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy rates were 92.0%, 94%.0, 93.9%, 92.2%, and 93.0%, respectively. When a cutoff point of grade 1 was used, the sensitivity, specificity, PPV, NPV, and accuracy rates were 26.0%, 10.0%, 10.0%, 57.5%, and 63.0, for color Doppler imaging; 40.0%, 10.0%, 10.0%, 62.5%, and 70.0% for power Doppler imaging; and 84.0%, 94.0%, 93.0%, 85.5%, and 89.0% for SMI. When a cutoff value of 3.94 was used for the mean strain ratio, the sensitivity, specificity, PPV, NPV, and accuracy rates were 78.0%, 92.0%, 90.7%, 80.7%, and 85.0%, respectively. A statistically significant correlation was detected between SMI, strain elastography, and visual analog scale scores (P < .001).

CONCLUSIONS

The combination of SMI and B-mode sonography was found to have excellent diagnostic performance for lateral epicondylosis. Neovascularzation in patients' tendons with lateral epicondylosis was identified much better with SMI compared to color or power Doppler imaging.

Fibrosis imaging: Current concepts and future directions

Fibrosis plays an important role in many different pathologies. It results from tissue injury, chronic inflammation, autoimmune reactions and genetic alterations, and it is characterized by the excessive deposition of extracellular matrix components. Biopsies are routinely employed for fibrosis diagnosis, but they suffer from several drawbacks, including their invasive nature, sampling variability and limited spatial information. To overcome these limitations, multiple different imaging tools and technologies have been evaluated over the years, including X-ray imaging, computed tomography (CT), ultrasound (US), magnetic resonance imaging (MRI), positron emission tomography (PET) and single-photon emission computed tomography (SPECT). These modalities can provide anatomical, functional and molecular imaging information which is useful for fibrosis diagnosis and staging, and they may also hold potential for the longitudinal assessment of therapy responses. Here, we summarize the use of non-invasive imaging techniques for monitoring fibrosis in systemic autoimmune diseases, in parenchymal organs (such as liver, kidney, lung and heart), and in desmoplastic cancers. We also discuss how imaging biomarkers can be integrated in (pre-) clinical research to individualize and improve anti-fibrotic therapies.

Ultrasonography of pediatric urogenital emergencies: review of classic and new techniques

Urogenital emergencies are fairly common in the pediatric population, and a timely and correct diagnosis is necessary to avoid possible future infertility. In this field, ultrasonography is essential, as it has the advantages of being radiation-free and readily accessible. In particular, a high-frequency transducer allows precise evaluation of the morphology and vascularity of the scrotum, which is on the surface of the body. Beyond conventional techniques, new advanced imaging techniques have been developed, including elastography and contrast-enhanced ultrasonography. However, several pitfalls remain in the diagnosis of urogenital diseases using ultrasonography. Thus, accurate knowledge and sufficient experience with the technique are essential for making a correct diagnosis. This review provides an overview of pediatric urogenital emergency pathologies and recent ultrasonography techniques.

Ultrasound-based imaging methods of the kidney-recent developments

In recent years, several novel ultrasound (US)-based techniques have emerged for kidney diagnostic imaging, including tissue stiffness assessment with elastography, Ultrasensitive Doppler techniques, and contrast-enhanced ultrasonography to assess renal microvascularization. Renal elastography has become available with the development of noninvasive quantitative techniques, following the rapidly growing field of liver fibrosis diagnosis. With the increased incidence of chronic kidney disease, noninvasive diagnosis of renal fibrosis can be of critical value. However, it is difficult to simply extend the application of US elastography from one organ to the other due to anatomic and technical issues. Today, renal elastography appears to be a promising application that, however, still requires optimization and validation. New ultrasensitive Doppler techniques improve the detection of slow blood flow and can be used alone or after administration of US contrast agents. These microbubble-based agents are extremely well tolerated and can be administered even in cases of impaired renal function. Despite the lack of approval, they improve the characterization of atypical renal masses, complex cystic renal masses, and peripheral vascular disorders. Dynamic contrast-enhanced US is based on quantification of the signal intensity from region of interest and mathematical fits of the time-intensity curves. Perfusion-related parameters can be extracted for the monitoring of vascular changes in the renal parenchyma and in tumors in order to evaluate drug response. This estimation of renal perfusion depends on many parameters that should be kept constant for follow-up studies, and, when possible, an internal reference should be used to normalize the measurements.

Usefulness of Microvascular Ultrasonography in Differentiating Metastatic Lymphadenopathy from Tuberculous Lymphadenitis

This study was undertaken to evaluate the usefulness of vascular pattern analysis on microvascular ultrasonography in distinguishing metastatic lymphadenopathy from tuberculous lymphadenitis, compared with conventional power Doppler ultrasonography, and to evaluate inter-observer agreement for microvascular ultrasonography. Thirty-four patients with metastatic lymphadenopathy and 27 patients with tuberculous lymphadenitis were included. The level of inter-observer agreement was excellent or good for all aspects of vascular pattern analysis on both ultrasonographic examinations. Vascular distribution, internal vascularity and internal vascular features of lymph nodes on microvascular ultrasonography differed significantly different (p ≤ 0.002) between metastatic lymphadenopathy and tuberculous lymphadenitis. A central vascular pattern with displacement was prevalent in metastasis, and an avascular pattern was more frequent in tuberculosis. Internal vascularity of metastasis was higher than that of tuberculosis. Vascular patterns on power Doppler ultrasonography did not differ significantly. Vascular pattern analysis using microvascular ultrasonography can be helpful in differentiating metastatic lymphadenopathy from tuberculous lymphadenitis with good inter-observer agreement.